sirolimus and Hyperplasia

Topics: Chronic Disease; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Hyperplasia; Hypertension, Portal; Immunosuppressive Agents; Liver; Liver Regeneration; Male; Middle Aged; Sirolimus

Exaggerated neointimal hyperplasia is considered as the primary mechanism for increased restenosis in patients with diabetes mellitus (DM) treated with bare-metal stent. However, the vessel response in DM and non-DM treated with different drug-eluting stents (DES) has not been systematically evaluated.. We investigated 3D intravascular ultrasound (postprocedure and 6 to 9 months) in 971 patients (267 with DM and 704 without DM) treated with sirolimus- (n=104), paclitaxel- (n=303), zotarolimus- (n=391), or everolimus- (n=173) eluting stents. Volumetric data were standardized by length as volume index (VI). At postprocedure, lumen VI at the stented segment was significantly smaller in DM than in non-DM, whereas vessel VI was similar between the 2 groups. At follow-up, neointimal obstruction and maximum cross-sectional narrowing (neointimal area/stent area) were not significantly different between the 2 groups with no interaction for the DES type. Consequently, lumen VI was smaller in DM than in non-DM at follow-up. In the reference segments, residual plaque burden at postprocedure was significantly greater in DM than in non-DM, although change in lumen VI was similar between the 2 groups. The arterial responses at the reference segments also showed no interaction for the DES type.. DM and non-DM lesions showed similar vessel response in both in-stent and reference segments regardless of the DES type. In the DES era, the follow-up lumen in DM patients seems to be determined primarily by the smaller lumen at postprocedure rather than exaggerated neointima within the stent or plaque proliferation at the reference segments.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Diabetes Mellitus; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Linear Models; Male; Middle Aged; Multicenter Studies as Topic; Multivariate Analysis; Neointima; Paclitaxel; Predictive Value of Tests; Prosthesis Design; Randomized Controlled Trials as Topic; Retrospective Studies; Risk Factors; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional

The benefit of drug-eluting stents (DES) is the remarkable reduction in the rates of both restenosis and target lesion revascularization. However, the risk of thrombotic complications extends further in DES-implanted arteries compared with those treated with bare-metal stents (BMS). Moreover, in-stent thrombosis (IST) and delayed arterial healing in DES-treated arteries have been identified by histological examination. At autopsy, proliferation of a monolayer composed of endothelium-like cells over stent struts in DES receiving arteries has been observed; however, these cells are negative for well-accepted endothelial cell markers. An inflammatory reaction against the stent struts is apparent after implantation of BMS and paclitaxel-eluting stents, whereas after sirolimus-eluting stents (SES), minimal inflammation is seen up to 6 months after device implantation. IST and in-stent restenosis, both possibly related to a hypersensitivity phenomena, are peculiar to DES, albeit relatively infrequent. A case of enhanced neointimal hyperplasia at 6 months after SES implantation with massive inflammatory reaction including eosinophils, and fibrin deposition is reported here. Observation of the morphological alterations after DES implantation by imaging techniques may furnish important information, but lack of precise comparative data between vascular imaging and histopathology leads to improper interpretation of imaging. Ex vivo imaging using angioscopy, intravascular ultrasound, and optical coherency tomography of SES implantation is presented and the images are compared with the corresponding pathological section.

Topics: Coronary Vessels; Drug-Eluting Stents; Humans; Hyperplasia; Inflammation; Neointima; Paclitaxel; Risk Factors; Sirolimus; Thrombosis

Intimal hyperplasia is central to the pathology of vein graft re-stenosis, and despite considerable advances in our understanding of vascular biology since it was first described 100 years ago, it is still a significant clinical problem. Recent decades have seen the development of many new therapeutic agents aimed at treating this condition, but the successes of laboratory studies have not been replicated in the clinic yet. This review discusses these therapeutic agents, how their modes of action relate to the pathogenesis of vein graft intimal hyperplasia, and considerations of ways in which such therapy may be improved in the future.

Topics: Animals; Anticoagulants; Atherosclerosis; Cell Proliferation; Coronary Artery Bypass; Graft Occlusion, Vascular; Humans; Hyperplasia; Muscle, Smooth, Vascular; Platelet Aggregation Inhibitors; Saphenous Vein; Shear Strength; Sirolimus; Stress, Mechanical; Tunica Intima; Vascular Patency; Veins

The only routinely available tool for assessing many features of stent implantation, intravascular ultrasound (IVUS) has become indispensable in trials of drug-eluting stents (DESs) and is currently the best way to identify or exclude causes of DES failure. Although IVUS resolution is not sufficient for determining reendothelialization, serial (postprocedure and follow-up) IVUS can measure intimal hyperplasia (IH), assess acute and late incomplete stent apposition, detect the presence and persistence of edge dissections, assess vascular responses such as remodeling, study edge effects, compare overlapping with nonoverlapping segments, and look for causes of restenosis and thrombosis. Percentage IH volume is one IVUS measure of efficacy that has been routinely assessed and compared in studies of DESs; IH volume and external elastic membrane, luminal, and stent cross-sectional area are others. This review details and evaluates IVUS findings in the important clinical trials conducted with the first-generation DESs: a sirolimus-eluting stent, a polymeric paclitaxel-eluting stent, and a nonpolymeric paclitaxel-eluting stent. IVUS results apparent in DES failure (restenosis and thrombosis) are also examined.

Topics: Anti-Bacterial Agents; Coronary Restenosis; Coronary Thrombosis; Drug-Eluting Stents; Humans; Hyperplasia; Sirolimus; Tunica Intima; Ultrasonography, Interventional

The goal of this study was to use angioscopy to investigate the amount of neointimal coverage after sirolimus-eluting stent (SES) implantation.. Sirolimus-eluting stents reduce intimal hyperplasia.. We used angioscopy to evaluate 37 consecutive stented coronary artery lesions (15 SES and 22 bare-metal stents [BMS]) in 25 patients (18 men, 7 women) at 3 to 6 months after stent implantation. Angioscopic evaluation focused on: 1) neointimal coverage of stent struts, and 2) the existence of thrombi. The degree of neointimal coverage was classified as grade 0 when there was no neointimal coverage (similar to immediately after the implantation); grade 1 when stent struts bulged into the lumen, but were covered and still translucently visible; grade 2 when stent struts were visible but not clearly seen (not translucent); and grade 3 when stent struts were not visible because they were embedded in the neointima.. Thrombi were identified in eight stented segments, tended to be more common with SES (p = 0.14), but were not seen on angiography. Three of the 15 SES (20%) had grade 0 neointimal coverage, and only 2 SES (13.3%) had complete coverage (grades 2/3). In contrast, all 22 BMS showed complete intimal coverage (grades 2/3). Thrombi were more common in stents with incomplete neointimal coverage (p = 0.09).. The SES had incomplete neointimal coverage three to six months after implantation, and this was associated with subclinical thrombus formation.

Topics: Aged; Angioscopy; Blood Vessel Prosthesis Implantation; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Coronary Thrombosis; Delayed-Action Preparations; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Sirolimus; Stents; Tunica Intima; Wound Healing

Restenosis is a direct result of vessel injury, local inflammation, and remodeling following balloon angioplasty and coronary stenting resulting in luminal narrowing. The process involves a complex interplay of released growth factors that stimulate smooth muscle cells (SMCs) to migrate and proliferate, as well as activating endothelial cells (ECs) at injury sites. The latter re-establishes the luminal endothelial monolayer that keeps a barrier to circulating cells from underlying extracellular matrix and SMCs. Understanding the cellular mechanisms of intimal hyperplasia and re-endothelialization is important in that uncontrolled cellular processes account for coronary luminal narrowing, leading to the recurrence of clinical symptoms, hospitalizations, and repeat interventions. The evolution of drug-eluting stents that inhibit intimal hyperplasia has revolutionized percutaneous coronary interventions in that potential late luminal narrowing is attenuated. Sirolimus and paclitaxel are two medications utilized for their efficacy at inhibiting intimal hyperplasia and subsequent clinical events. The effects of these drugs on EC biology have not been well investigated. This article discusses basic cellular processes of vessel repair after balloon angioplasty and stenting, and focuses on the differential molecular mechanisms of sirolimus and paclitaxel towards proliferation and migration. These drugs inhibit both SMC and EC proliferation, but by different mechanisms, and paclitaxel inhibits EC migration, whereas sirolimus does not. Their discriminating effects towards re-endothelialization may clinically differentiate these two drugs. Inhibiting re-endothelialization may translate into more adverse clinical events.

Topics: Antineoplastic Agents, Phytogenic; Blood Vessel Prosthesis Implantation; Coated Materials, Biocompatible; Coronary Restenosis; Coronary Vessels; Endothelium, Vascular; Humans; Hyperplasia; Immunosuppressive Agents; Paclitaxel; Prosthesis Design; Sirolimus; Stents; Tunica Intima

The development of stent has been a major advance in the treatment of obstructive coronary artery disease since the introduction of balloon angioplasty. However, neointimal hyperplasia occurring within the stent leading to in-stent restenosis is a main obstacle in the long-term success of percutaneous coronary intervention (PCI). The recent introduction of drug-eluting stents (DES) contributes a major breakthrough to interventional cardiology. Many large randomized clinical trials using DES have shown a remarkable reduction in angiographic restenosis and target vessel revascularization when compared with bare metal stents. The results of these trials also appear to be supported by evidence from everyday practice and non-controlled clinical trials. However, the expanded applications of DES, especially in treating complex lesions such as left main trunk, bifurcation, saphenous vein graft lesions, or in-stent restenosis, are still under evaluation with ongoing studies. With the availability of different types of DES in the market, the issue of cost should not be a deterrent and DES will eventually be an economically viable option for all patients. The adoption of DES in all percutaneous coronary intervention may become a reality in the near future. In this review article, we summarize the recent development and progress of DES as well as compare and update the results of clinical trials.

Topics: Angioplasty, Balloon, Coronary; Anti-Inflammatory Agents; Coated Materials, Biocompatible; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug Carriers; Growth Inhibitors; Humans; Hyperplasia; Paclitaxel; Prosthesis Design; Sirolimus; Stents; Thrombosis; Treatment Outcome; Tunica Intima

The use of intracoronary stents represent a major breakthrough in the armamentarium of interventional cardiology. Stents reduce significantly the incidence of recurrent stenosis (in-stent restenosis) via an improved post-procedure luminal diameter and an abrogation of the constrictive remodeling of the arterial wall. However, stent-related arterial injury results in intense proliferative and inflammatory responses and severe intimal hyperplasia, which, in 20% to 40% of the patients, may end up with clinically significant in-stent restenosis. Efficient prevention of in-stent restenosis has yet to be found. Systemic treatments have failed because they don't take into account the specific physiopathology and, most importantly, the focal nature of in-stent intimal hyperplasia. Hence, local prevention appears to be a straightforward approach to the unsolved issue of in-stent restenosis. In situ beta- or gamma-irradiation (brachytherapy) has received much attention as a curative treatment of in-stent restenosis but is not indicated for prevention. In contrast, drug-releasing stents have been tested in experimental models and have already provided very promising results in randomized clinical trials. Most of clinical studies have been performed with the antiproliferative agents sirolimus and paclitaxel, but other agents are under scrutiny. In addition, important research is carried out, in which the efficacy of antiproliferative genes is investigated. Clearly, drug-releasing stents are on the verge of profoundly modifying our practice of interventional cardiology. However, several questions remain unanswered as regard to the long term efficacy/toxicity and the cost-effectiveness of this new approach.

Topics: Animals; Coronary Restenosis; Drug Delivery Systems; Humans; Hyperplasia; Paclitaxel; Sirolimus; Stents; Tunica Intima

The short-term efficacy of drug-eluting stents has been validated in the coronary circulation, particularly with the drugs rapamycin and paclitaxel. The physical environment of the infrainguinal arteries is very different from the coronary circulation. Self-expanding stents are necessary in the femoropopliteal segment, which is subject to recurrent external forces. These include flexion at the knee, compression within the adductor hiatus, rotation and longitudinal compression. Thus, the properties required of a drug coating is likely be very different from those used in coronary arteries. This would appear to be borne out by SIROCCO, the only published study to date evaluating drug-eluting stents in the noncoronary circulation. SIROCCO began as a prospective randomized 36 patient trial comparing rapamycin coated to uncoated self-expanding SMART stents in the femoropopliteal segment. The first phase of SIROCCO demonstrated reduction of intimal hyperplasia by rapamycin. However, the study is being repeated to optimize the rate of drug elution, and multiple stent fractures seen in the first phase of the study necessitated modification of stent design. Considerable further study of drug eluting stents will be required in each vascular bed to determine the ideal stent/drug combination, and to establish clinical efficacy.

Topics: Animals; Arterial Occlusive Diseases; Femoral Artery; Humans; Hyperplasia; Paclitaxel; Popliteal Artery; Radiography; Recurrence; Sirolimus; Stents; Tunica Intima; Vascular Patency

One of the major advancements in interventional cardiology has been the introduction of drug-eluting stents (DES). By incorporating anti-proliferative agents onto the surface of the stent, neointimal hyperplasia occurring within the stent, which is the main cause of in-stent restenosis (ISR), is markedly reduced. Stents coated with agents, like sirolimus or paclitaxel, when compared to bare metal stents (BMS), had shown remarkable reduction in binary restenosis and target vessel revascularisation (TVR) rates in large randomised clinical trials. The final hurdle of percutaneous coronary intervention (PCI) seems to have been overcome. However, there are still many uncertainties that need to be clarified. The long-term safety of DES remains a major concern; in particular, stent thrombosis and incomplete stent apposition. In the real world, there is a tendency to implant DES in smaller vessels, longer lesions, and complex lesions, as these are high risk for ISR and would yield the greatest benefit. Whether the excellent results of clinical trials of DES can be replicated in these more complex lesions is still unknown and awaits further studies. Although early experience with DES in complex lesions had shown improved results, a higher number of ISR were seen. Finally, the high cost of these devices has precluded their use in all patients undergoing PCI and deliberation among healthcare policy-makers on who should receive DES has centred not only on financial, but also legal and ethical issues. As DES has not completely eliminated ISR and not all patients can afford DES, ISR may survive the initial assault of DES, albeit considerably less in number, for now.

Topics: Coronary Restenosis; Humans; Hyperplasia; Metals; Paclitaxel; Prosthesis Design; Sirolimus; Stents; Thrombosis; Tunica Intima

To assess the vessel-healing pattern of Ultimaster drug-eluting stent using optical frequency domain imaging. Our hypothesis is that biodegradable polymer-based drug-eluting technology allows complete very early strut coverage.. The DISCOVERY 1TO3 study (Evaluation With OFDI of Strut Coverage of Terumo New Drug Eluting Stent With Biodegradable Polymer at 1, 2, and 3 Months) is a prospective, single-arm, multicenter study. A total of 60 patients with multivessel disease requiring staged procedure at 1 month were treated with Ultimaster. Optical frequency domain imaging was acquired at baseline, 1, 2, and 3 months. The primary end point is optical frequency domain imaging-assessed strut coverage at 3 months. Mean age of patients was 67.2±9.9 years, and 73.3% were male, and 36.7% presented with acute coronary syndrome. A total of 132 lesions were treated, with average 1.4 lesions per patient treated at baseline and 1.1 lesions treated at 1 month. Strut coverage at 3 months of single implanted stents (n=71, primary end point) was 95.2±5.2% and of combined single and overlapped stents was 95.4±4.9%. Strut coverage of combined single and overlapped stents at 1 (n=49) and 2 months (n=38) was 85.1±12.7% and 87.9±10.8%, respectively. The median neointimal hyperplasia thickness was 0.04, 0.05, and 0.06 mm, whereas mean neointimal hyperplasia obstruction was 4.5±2.4%, 5.2±3.4%, and 6.6±3.3% at 1, 2, and 3 months, respectively.. Nearly complete strut coverage was observed in this complex population very early after implantation of Ultimaster drug-eluting stent.. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01844843.

Topics: Absorbable Implants; Aged; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Europe; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Polyesters; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Risk Factors; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome; Wound Healing

Persistence of stent polymer coating has been associated with incomplete endothelialization, expansive vessel remodeling, neoatherosclerosis, and delayed healing associated with inflammation that may contribute to late adverse events.. The BICARE (Lepu Medical, Beijing, China) stent is a novel polymer-free, nanotechnology-based stent eluting sirolimus and probucol. As a first in human feasibility study, patients with a single de novo native coronary stenosis <30 mm in length and with reference vessel diameter from 2.5 to 4.0 mm underwent revascularization with the BICARE stent. The primary endpoint of target lesion failure (TLF) was assessed at 30 days. Secondary endpoints included in-stent late lumen loss and proportion of uncovered or malapposed stent struts by optical coherence tomography at 4-month angiographic surveillance.. Among 32 consecutive patients (age, 55.7 ± 8.7 years; men, 62.5%; diabetes, 18.8%), the average baseline reference vessel diameter and lesion length were 2.85 ± 0.48 mm and 15.0 ± 5.6 mm, respectively. At 30 days there was no occurrence of TLF. At 4 months (angiographic follow-up, N=32), angiographic in-stent late loss was 0.14 ± 0.19 mm, and the in-stent binary restenosis rate was 3.1%. Complete strut coverage was 98.2% with 0.2% malapposition among 16,751 analyzed struts. At 18 months, TLF occurred in 3 (9.4%) patients related to repeat revascularization with no adverse safety events identified.. The preliminary feasibility and safety of a polymer-free, dual-drug eluting stent are demonstrated by absence of early adverse safety events and favorable angiographic suppression of neointimal hyperplasia. Stent imaging suggests favorable healing with extensive stent strut coverage and very low malapposition. These findings further inform comparison with biopermanent polymer DES.

Topics: Cardiovascular Agents; China; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Drug Combinations; Drug-Eluting Stents; Feasibility Studies; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Probucol; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

To evaluate the effects of the everolimus-eluting Xience™/Promus™ stent (EES) and the sirolimus-eluting Cypher™ stent (SES) on intimal hyperplasia (IH) in diabetic patients.. Patients with diabetes mellitus have increased risk of in-stent restenosis after coronary stent implantation due to intimal hyperplasia (IH).. In a sub study of the Randomized Comparison of Everolimus-Eluting and Sirolimus-Eluting Stents in Patients Treated with Percutaneous Coronary Intervention (SORT OUT IV trial), serial intravascular ultrasound (IVUS) 10-month follow-up data were available in 88 patients, including 48 EES and 40 SES treated patients. IVUS endpoints included IH volume, in-stent % volume obstruction and changes in external elastic membrane (EEM) volume.. Compared with the SES group, IH volume was increased in the EES group [median (interquartile range): 2.8 mm(3) (0.0-12.6) vs. 0.0 mm(3) (0.0-1.1), P = 0.001]. In-stent % volume obstruction was increased in EES compared to SES [median (interquartile range): 1.6% (0.0-8.2) vs. 0.0% (0.0-1.0), P = 0.001]. Peri-stent external elastic membrane (EEM) volume: (post procedure vs. follow-up EES [300 mm(3) (219-491) vs. 307 mm(3) (223-482), P = 0.73] and SES [316 mm(3) (235-399) vs. 323 mm(3) (246-404), P = 0.05]) and peri-stent plaque volume: EES [163 mm(3) (103-273) vs. 184 mm(3) (115-291), P = 0.18] and SES [186 mm(3) (139-248) vs. 175 mm(3) (153-243), P = 0.26]) were unchanged in both groups. In the proximal reference segment a significant increase in plaque area was seen in the EES group only, without vascular remodeling.. In diabetic patients, EES stent implantation was associated with increased IH volume obstruction without involvement of vascular remodeling.

Topics: Aged; Cardiovascular Agents; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Diabetic Angiopathies; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prosthesis Design; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional; Vascular Remodeling

This study sought to assess device-specific outcomes after implantation of bare-metal stents (BMS), zotarolimus-eluting Endeavor Sprint stents (ZES-S), paclitaxel-eluting stents (PES), or everolimus-eluting stents (EES) (Medtronic Cardiovascular, Santa Rosa, California) in all-comer patients undergoing percutaneous coronary intervention.. Few studies have directly compared second-generation drug-eluting stents with each other or with BMS.. We randomized 2,013 patients to BMS, ZES-S, PES, or EES implantation. At 30 days, each stent group received up to 6 or 24 months of clopidogrel therapy. The key efficacy endpoint was the 2-year major adverse cardiac event (MACE) including any death, myocardial infarction, or target vessel revascularization, whereas the cumulative rate of definite or probable stent thrombosis (ST) was the key safety endpoint.. Clinical follow-up at 2 years was complete for 99.7% of patients. The MACE rate was lowest in EES (19.2%; 95% confidence interval [CI]: 16.0 to 22.8), highest in BMS (32.1%; 95% CI: 28.1 to 36.3), and intermediate in PES (26.2%; 95% CI: 22.5 to 30.2) and ZES-S (27.8%; 95% CI: 24.1 to 31.9) groups (chi-square test = 18.9, p = 0.00029). The 2-year incidence of ST in the EES group (1%; 95% CI: 0.4 to 2.2) was similar to that in the ZES-S group (1.4%; 95% CI: 0.7 to 2.8), whereas it was lower compared with the PES (4.6%, 95% CI: 3.1 to 6.8) and BMS (3.6%; 95% CI: 2.4 to 5.6) groups (chi-square = 16.9; p = 0.0001).. Our study shows that cumulative MACE rate, encompassing both safety and efficacy endpoints, was lowest for EES, highest for BMS, and intermediate for PES and ZES-S groups. EES outperformed BMS also with respect to the safety endpoints with regard to definite or probable and definite, probable, or possible ST. (PROlonging Dual antiplatelet treatment after Grading stent-induced Intimal hyperplasia studY [PRODIGY]; NCT00611286).

Topics: Aged, 80 and over; Chi-Square Distribution; Clopidogrel; Coronary Restenosis; Coronary Thrombosis; Drug Administration Schedule; Drug Therapy, Combination; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Italy; Kaplan-Meier Estimate; Male; Metals; Middle Aged; Myocardial Infarction; Neointima; Paclitaxel; Percutaneous Coronary Intervention; Platelet Aggregation Inhibitors; Prosthesis Design; Risk Factors; Sirolimus; Stents; Ticlopidine; Time Factors; Treatment Outcome

Restenosis is a frequent complication of coronary stent implantation, especially bare metal stent (BMS) implantation. The everolimus-eluting stent (EES) has previously been shown to be efficacious in the treatment of de novo lesions. We performed this study to evaluate clinical, angiographic and IVUS results after EES implantation for the treatment of BMS ISR. XERES was a prospective, multicentre, nationwide study, enrolling 97 consecutive patients with in-stent restenosis (ISR) after BMS implantation across 20 centres in France. Suitable lesions had a reference vessel diameter between 2.5 mm and 4 mm, a length ≤22 mm and a diameter stenosis between 50 and 100%. The primary endpoint was angiographic in-stent late loss (LL) as determined by quantitative coronary angiography (QCA) at nine-month follow-up. QCA was required to be performed in each included patient and IVUS was performed in a subgroup of 27 patients. At nine-month follow-up, the in-stent late loss was 0.35±0.63 mm. The rate of in-stent binary restenosis was 12.22%, including two complete occlusions. The average volume of neointimal hyperplasia was 15.6±9.9 mm3. The in-stent percent volume obstruction was 8.5±5.2%. The in-segment percent area and diameter obstruction were 32±17% and 27±11%, respectively. Two initial malappositions were persistent and two other patients had late acquired stent malapposition. The cumulative incidence of major adverse cardiac events (MACE) was 10.1%. EES for the treatment of bare metal in-stent restenosis seemed safe and efficacious.

Topics: Adult; Aged; Aged, 80 and over; Coronary Angiography; Coronary Restenosis; Drug-Eluting Stents; Everolimus; Female; Follow-Up Studies; France; Humans; Hyperplasia; Male; Middle Aged; Myocardial Infarction; Neointima; Prospective Studies; Sirolimus; Stents; Thrombosis; Ultrasonography, Interventional

Nobori is a novel biolimus A9-eluting stent (BES) coated with a biodegradable polymer only on the abluminal side, which degrades over 6-9 months post-stent deployment. The course of vessel reaction after deployment at these time points remains unclear.. We serially evaluated 28 BES implanted in de novo coronary lesions of 23 patients using optical coherence tomography (OCT) at 6 and 12 months post-stenting. Standard OCT variables, the percentage of stent with peri-strut low-intensity area (PLIA, a region around stent struts homogenously showing lesser intensity than the surrounding tissue, suggesting fibrin deposition or impaired neointima maturation) and that with in-stent thrombi were evaluated. There was a significant, but small increase in neointimal thickness (72 ± 23 to 82 ± 25 µm, P=0.006) from the 6- to the 12-month follow-up, without a significant decrease in minimum lumen area (P=0.30). The incidences of uncovered and malapposed struts were low at 6 months and reduced further at 12 months (3.96 ± 3.97% to 1.51 ± 1.63%, P=0.001, and 0.50 ± 1.84% to 0.06 ± 0.24%, P=0.20, respectively). The frequency of stent with PLIA decreased during the follow-up (57% to 32%, P=0.05) and that with in-stent thrombi also numerically decreased (7% to 0%, P=0.24).. Neointimal hyperplasia was persistently suppressed following BES implantation up to 12 months. Simultaneously, favorable vessel healing was achieved at 6 months without a delaying adverse reaction for up to 12 months.

Topics: Aged; Biodegradable Plastics; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Neointima; Regeneration; Sirolimus; Tomography, Optical Coherence

This study was designed to compare neointimal hyperplasia and peri-stent arterial remodeling after implantation of everolimus-eluting stent (EES) versus sirolimus-eluting stent (SES) using intravascular ultrasound (IVUS). The study population was a subgroup of 278 patients from the EXCELLENT trial, a randomized study comparing EES to SES in de novo coronary artery lesions (total n = 1,443, 3:1 randomization) who underwent post-PCI and 9-month follow-up IVUS evaluation. There were 209 patients in the EES group and 69 in the SES group. Baseline clinical and angiographic characteristics were similar between the two groups except for age and target lesion locations. At 9 months, percent neointimal volume obstruction did not differ between EES and SES (2.6 ± 4.0 % vs. 2.5 ± 4.8 %, p = 0.814). However, the relative change in the vessel (4.3 ± 13.7 % vs. 8.8 ± 18.6 %, p = 0.030) and plaque volume index (4.2 ± 17.4 % vs. 10.5 ± 22.3 %, p = 0.016) of the stented segment from post-intervention to follow-up was significantly less with EES than with SES. In addition, positive peri-stent vascular remodeling defined as an increase in vessel volume index >10 % (27.8 vs. 42.0 %, p = 0.027) and late acquired stent malapposition (LASM, 1.9 vs. 15.9 %, p < 0.001) were observed less frequently with EES than SES. EES and SES were similarly effective in reducing neointimal hyperplasia. However, positive peri-stent vascular remodeling and LASM occurred less frequently with EES than SES.

Topics: Aged; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Logistic Models; Male; Middle Aged; Multivariate Analysis; Neointima; Odds Ratio; Percutaneous Coronary Intervention; Predictive Value of Tests; Prosthesis Design; Republic of Korea; Risk Factors; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional

Everolimus-eluting stents (EES) have shown favorable clinical outcomes. However, there have been no studies evaluating early vascular response after EES implantation. We designed a prospective study to compare the neointimal response between zotarolimus-eluting stents (ZES) and EES at 3 and 12 months using serial optical coherence tomography examinations.. Sixty patients who underwent 3-month and 12-month follow-up optical coherence tomography (36 EES, 24 ZES) were included. Neointimal coverage and malapposition were evaluated using a strut-based analysis at both 3 and 12 months. Neointimal hyperplasia area and thrombus were assessed. ZES showed a higher incidence of covered struts (81.5 vs. 77.1%, P<0.0001) and lower incidence of malapposed struts (1.4 vs. 2.3%, P=0.001) than EES at 3 months. However, at 12 months, EES showed a slightly higher incidence of covered struts (96.4 vs. 93.6%, P<0.0001) and a lower incidence of malapposed struts (0.9 vs. 1.1%, P=0.03) than ZES. Neointimal hyperplasia area was greater in the ZES group than in the EES group at both 3 and 12 months (0.77 vs. 0.49 mm, P=0.03 and 1.50 vs. 0.97 mm, P=0.01, respectively). No significant difference in the incidence of thrombus was observed at both 3 and 12 months.. ZES showed rapid neointimal healing compared with EES at 3 months. However, at 12 months, EES had a slightly better vascular healing profile than ZES.

Topics: Aged; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Observer Variation; Odds Ratio; Percutaneous Coronary Intervention; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Reproducibility of Results; Republic of Korea; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome; Wound Healing

Histologic experimental studies have reported incomplete neointimal healing in overlapping with respect to nonoverlapping segments in drug-eluting stents (DESs), but these observations have not been confirmed in human coronary arteries hitherto. On the contrary, angiographic and optical coherence tomography studies suggest that DES overlap elicits rather an exaggerated than an incomplete neointimal reaction.. Optical coherence tomography studies from 2 randomized trials including sirolimus-eluting, biolimus-eluting, everolimus-eluting, and zotarolimus-eluting stents were analyzed at 9- to 13-month follow-up. Coverage in overlapping segments was compared versus the corresponding nonoverlapping segments of the same stents, using statistical pooled analysis.. Forty-two overlaps were found in 31 patients: 11 in sirolimus-eluting stents, 3 in biolimus-eluting stents, 17 in everolimus-eluting stents, and 11 in zotarolimus-eluting stents. The risk ratio of incomplete coverage was 2.35 (95% CI 1.86-2.98) in overlapping versus nonoverlapping segments. Thickness of coverage in overlaps was only 85% (95% CI 81%-90%) of the thickness in nonoverlaps. Significant heterogeneity of the effect was observed, especially pronounced in the comparison of thickness of coverage (I(2) = 90.31).. The effect of overlapping DES on neointimal inhibition is markedly heterogeneous: on average, DES overlap is associated with more incomplete and thinner coverage, but in some cases, the overlap elicits an exaggerated neointimal reaction, thicker than in the corresponding nonoverlapping segments. These results might help to understand why overlapping DES is associated with worse clinical outcomes, both in terms of thrombotic phenomena and in terms of restenosis and revascularization.

Topics: Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Everolimus; Feasibility Studies; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Neointima; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Incomplete stent endothelialization is associated with late and very late stent thrombosis. In a post hoc analysis of the BASE-ACS trial, we sought to assess neointimal coverage and coronary flow reserve (CFR) 9 months after implantation of titanium-nitride-oxide-coated bioactive stents (BAS) versus everolimus-eluting stents (EES) in patients with acute coronary syndrome (ACS). In the BASE-ACS trial, 827 patients with ACS were randomized to receive either BAS or EES. In the current study, we examined neointimal growth and strut coverage by optical coherence tomography and CFR by trans-thoracic echocardiography in 28 consecutive non-diabetic patients with the culprit lesion in the left anterior descending coronary artery. The primary endpoints were binary stent strut coverage and CFR at 9-month follow-up. A total of 13 patients were included in the BAS group (2,033 struts); 15 in the EES group (2,898 struts). Binary stent strut coverage was higher and malapposed struts lower with BAS versus EES (99.4 vs 89.2, and 0.2 vs 4.6%, respectively, p < 0.001 for both). Neointimal hyperplasia thickness was greater with BAS versus EES (274.2 vs 100.1 μm, respectively, p < 0.001). CFR was lower with EES versus BAS (2.2 ± 0.8 vs. 3.0 ± 0.5, respectively, p = 0.001). Abnormal CFR (<2.5) were detected in 10 patients in the EES group versus one in the BAS group (p = 0.002). The current study demonstrated that in patients with ACS, BAS resulted in improved neointimal stent strut coverage and better coronary vasodilator function as compared with EES at 9-month follow-up.

Topics: Acute Coronary Syndrome; Cardiovascular Agents; Coated Materials, Biocompatible; Coronary Circulation; Coronary Vessels; Drug-Eluting Stents; Echocardiography, Doppler, Color; Echocardiography, Doppler, Pulsed; Everolimus; Humans; Hyperplasia; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Single-Blind Method; Sirolimus; Stents; Time Factors; Titanium; Tomography, Optical Coherence; Treatment Outcome; Vasodilation

The purpose of this pre-specified analysis of the PROlonging Dual antiplatelet treatment after Grading stent-induced Intimal hyperplasia studY (PRODIGY) was to assess device-specific outcomes relative to different duration of dual antiplatelet therapy (DAPT) after Everolimus- (EES), Paclitaxel (PES), Zotarolimus- (ZES-S) eluting, or bare metal stents (BMS).. We randomized 2013 patients to BMS, ZES-S, PES, or EES implantation. At 30 days, each stent group underwent up to 6 or 24 months clopidogrel therapy. The primary endpoint, which was a composite of death, myocardial infarction, or cerebrovascular accident, did not differ in patients receiving BMS [HR: 0.89 (95% CI: 0.54-1.45)], PES [HR: 0.74 (95% CI: 0.43-1.25)], or EES [HR: 0.63 (95% CI: 0.33-1.21)] implantation across DAPT groups, whereas it was significantly higher in ZES-S patients undergoing long when compared with short-term DAPT therapy (HR: 2.85, P = 0.0018), with positive interaction testing (P-value = 0.004). At the 6-month landmark analysis, heterogeneity across stent types persisted for the primary study endpoint and other secondary clinical outcomes, whereas patients receiving PES showed a significantly higher rate of definite, probable and definite, probable, possible stent thrombosis in the short DAPT regimen. No association in absolute or relative terms was noted between stent potency in inhibiting intimal hyperplasia and greater vulnerability to shorter DAPT therapy.. Our study suggests that optimal duration of DAPT may be stent-specific and it does not support a clear association between stent potency and vulnerability to shorter DAPT therapy. Trial Registration clinicaltrials.gov Identifier: NCT00611286. http://clinicaltrials.gov/ct2/show/NCT00611286?term=prodigy&rank=2.

Topics: Aged; Clopidogrel; Coronary Restenosis; Coronary Vessels; Drug Administration Schedule; Drug Therapy, Combination; Drug-Eluting Stents; Everolimus; Female; Graft Occlusion, Vascular; Humans; Hyperplasia; Male; Myocardial Infarction; Platelet Aggregation Inhibitors; Sirolimus; Stents; Stroke; Ticlopidine; Tunica Intima

The Sparrow stent system (Biosensors International) consists of a self-expanding, ultra-thin nitinol stent mounted within a 0.014″ guidewire designed for small or tortuous coronary lesions. We compared the intravascular ultrasound (IVUS) findings between the novel self-expanding sirolimus-eluting stent (Sparrow-SES) and a conventional balloon-expandable sirolimus-eluting stent (Cypher-SES) in patients with small coronary disease.. We examined 14 lesions treated with the Sparrow-SES from CARE II, compared with 22 small vessel lesions treated with Cypher-SES. IVUS examination was performed post-procedure and 8 months later. Volumetric data were standardized by length as volume index (VI; mm³/mm).. While baseline stent VI trended smaller in Sparrow-SES, follow-up stent VI became similar between the 2 groups due to a significant increase of stent VI in self-expanding Sparrow-SES during the follow-up period. At 8 months, Sparrow-SES showed greater neointima than Cypher-SES (0.8 ± 0.6 mm³/mm vs 0.2 ± 0.2 mm³/mm; P<.001). However, the decrease in lumen VI was only 0.3 ± 0.7 mm³/mm in Sparrow-SES, as compared to 0.1 ± 0.3 mm³/mm in Cypher-SES (P=.259), since the late loss due to neointimal hyperplasia was partly counterbalanced by the chronic stent expansion in Sparrow-SES.. While 8-month follow-up of Sparrow-SES revealed greater amounts of neointimal hyperplasia compared with conventional Cypher-SES, chronic stent expansion preserved the lumen by increasing stent volume. This novel, guidewire-based, self-expanding stent system designed to be delivered through complex anatomies may be useful to treat patients with small-caliber coronary lesions by offering sufficient lumen preservation at follow-up.

Topics: Aged; Coronary Disease; Coronary Vessels; Drug-Eluting Stents; Equipment Design; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Neointima; Prospective Studies; Retrospective Studies; Single-Blind Method; Sirolimus; Treatment Outcome; Ultrasonography, Interventional

The purpose of this study was to investigate the vascular response of the everolimus-eluting stent (EES) compared with the paclitaxel-eluting stent (PES) using serial intravascular ultrasound (IVUS).. Data were obtained from the SPIRIT III trial, a multicentre, 2:1 randomised, controlled study comparing EES and PES in de novo native coronary artery lesions. IVUS images were eligible for volumetric analysis at eight-month follow-up in 158 lesions (EES: 113, PES: 45). At eight months, EES had a smaller neointimal volume index (VI: mm3/mm) (EES: 0.4±0.4 vs. PES: 0.8±0.8 mm3/mm, p=0.002) and also a smaller % neointimal obstruction (EES: 7.1±6.7% vs. PES: 11.1±10.5%, p=0.005) compared with PES. While there was no significant change in vessel VI with EES, there was a significant increase in vessel VI in PES during eight-month follow-up (EES: 0.1±1.2 vs. PES: 1.2±0.8 mm3/mm, p=0.001). There were no statistical differences in the frequency of edge dissection or incomplete stent apposition between the two groups.. Detailed IVUS analysis confirmed significantly less neointimal hyperplasia with EES compared with PES. While there was no increase in vessel volume with EES during the eight-month follow-up period, vessel enlargement was seen at the stented segment in PES.

Topics: Aged; Cardiovascular Agents; Chi-Square Distribution; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Japan; Male; Middle Aged; Neointima; Paclitaxel; Percutaneous Coronary Intervention; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Registries; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional; United States

As a substudy of the large, randomized ZEST (Comparison of the Efficacy and Safety of Zotarolimus-Eluting Stent with Sirolimus-Eluting and PacliTaxel-Eluting Stent for Coronary Lesions) trial comparing first- and second-generation drug-eluting stents, we evaluated intimal hyperplasia (IH) and vascular changes using volumetric intravascular ultrasound analysis.. Complete angiographic and volumetric intravascular ultrasound data immediately after stenting and at 9-month follow-up were available in 162 patients with 183 lesions: 61 sirolimus-eluting stents (SES), 64 paclitaxel-eluting stents (PES), and 58 zotarolimus-eluting stents (ZES). External elastic membrane, stent, lumen, and peristent plaque volumes (external elastic membrane minus stent) were normalized by stent length. Percent IH volumes were calculated as [IH volume/stent volume]×100, %. Reduction of minimal luminal area) was greater in PES than SES (-1.4±1.5 mm(2) versus -0.7±0.9 mm(2), P=0.003), whereas minimal luminal area change in ZES was not significantly different from SES (-1.2±1.0 mm(2) versus -0.7±0.9 mm(2), P=0.055). Percent IH volume was less in SES compared with PES (9.8±6.0% versus 17.5±11.2%, P=0.002) or with ZES (9.8±6.0% versus 18.2±7.6%, P=0.005). Comparing ZES versus PES, there were no significant differences in %IH volume (17.5±11.2% versus 18.2±7.6%, P=0.779) or changes in normalized lumen volume (-1.2±1.3 mm(2) versus -1.1±0.8 mm(2), P=0.452). Late stent malapposition was identified in 8 (13%) SES and 2 (3%) PES but in no ZES (P=0.050). Angiographic restenosis was detected in 6 lesions (3 PES and 3 ZES).. The degree of neointimal growth in ZES was similar to that in PES but less than that in SES. ZES had no late stent malappositions.. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00418067.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Sirolimus; Tunica Intima; Ultrasonography, Interventional

The NEVO sirolimus-eluting stent (NEVO SES) is a novel cobalt-chromium stent combining sirolimus release from reservoirs with bioabsorbable polymer to reduce spatial and temporal polymer exposure. The aim of this study was to assess the arterial response to the NEVO SES in a randomized, blinded comparison versus the surface-coated TAXUS Liberte paclitaxel-eluting stent (TAXUS Liberté PES) in human native coronary lesions using intravascular ultrasound (IVUS).. The NEVO ResElution-I IVUS substudy enrolled 100 patients (1:1 randomization). In addition to standard IVUS variables, uniformity of neointimal distribution within stents was evaluated in 3 dimensions by computing mean neointimal thickness within 12 equally spaced radial sectors on every 1-mm cross section along the stented segment. The NEVO SES showed significantly less neointimal proliferation (neointimal obstruction: 5.5±11.0% versus 11.5±9.7%, P=0.02), resulting in less late lumen area loss and smaller maximum cross-sectional narrowing at 6 months. The absolute variability of neointima distribution, assessed by the standard deviation of neointimal thickness within each stent, was significantly reduced with the NEVO SES compared with the TAXUS Liberté PES(0.04±0.04 mm versus 0.10±0.07 mm, P<0.0001). TAXUS Liberté PES showed significantly greater positive vessel remodeling than the NEVO SES (Δvessel volume index: 1.30±1.36 mm(3)/mm versus 0.36±0.63 mm(3)/mm, respectively, P=0.003).. The NEVO SES with focal release of sirolimus from reservoirs achieved significantly greater and more consistent suppression of neointimal hyperplasia than the surface-coated TAXUS Liberté PES. This was associated with less positive remodeling and no increased morphological or morphometric abnormalities surrounding the stent or at the stent margins.. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00714883.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Artery Disease; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Paclitaxel; Prospective Studies; Single-Blind Method; Sirolimus; Ultrasonography, Interventional

Patients with diabetes mellitus have increased risk of in-stent restenosis after coronary stent implantation due to neointimal hyperplasia (NIH). The aim of this study was to use quantitative coronary angiography (QCA) and volumetric intravascular ultrasound (IVUS) to evaluate the effects of the sirolimus-eluting Cypher® stent (SES) and the zotarolimus-eluting Endeavor® stent (ZES) on angiographic late lumen loss and intima hyperplasia in diabetic patients.. In the DiabeDES III trial, 127 patients were randomised to SES or ZES stent implantation. Angiographic 10-month follow-up data were available in 105 patients, including 48 SES and 57 ZES treated patients. Angiographic endpoints were in-stent late lumen loss and minimal lumen diameter. IVUS endpoints included NIH volume and in-stent percent volume obstruction. Baseline clinical characteristics and lesion parameters were similar in the two groups. At 10-month follow-up, angiographic in-stent late lumen loss (0.14±0.37 mm vs. 0.74±0.45 mm, p<0.001) was reduced and minimum lumen diameter was higher (2.36±0.53 mm vs. 1.96±0.65, p<0.001) in the SES group as compared to the ZES group. As compared to the ZES group, NIH volume was significantly reduced in the SES group (median [interquartile range]: 0.0 mm3 [0.0 to 1.2] vs. 16.5 mm3 [6.2 to 31.1], p<0.001). In-stent% volume obstruction was significantly reduced in SES as compared to ZES (median [interquartile range]: 0.0% [0.0-0.7] vs. 13.0% [6.7-20.8], p<0.001).. In diabetic patients, the SES reduced angiographic late lumen loss and inhibited NIH more effectively than ZES.

Topics: Aged; Angioplasty, Balloon, Laser-Assisted; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Diabetes Complications; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Neointima; Risk Factors; Single-Blind Method; Sirolimus; Treatment Outcome; Ultrasonography, Interventional

Inconsistent results in outcomes have been observed between the genders after drug-eluting stent implantation. The aim of this study was to investigate gender differences in neointimal proliferation for the Endeavor zotarolimus-eluting stent (ZES) and the Driver bare-metal stent (BMS). A total of 476 (n = 391 ZES, n = 85 BMS) patients whose volumetric intravascular ultrasound analyses were available at 8-month follow-up were studied. At 8 months, neointimal obstruction and maximum cross-sectional narrowing (CSN) were significantly lower in women than in men receiving ZES (neointimal obstruction 15.5 ± 9.5% vs 18.2 ± 10.9%, p = 0.025; maximum CSN 30.3 ± 13.2% vs 34.8 ± 15.0%, p = 0.007). Conversely, these parameters tended to be higher in women than in men receiving BMS (neointimal obstruction 36.3 ± 15.9% vs 27.5 ± 17.2%, p = 0.053; maximum CSN 54.3 ± 18.6% vs 45.6 ± 18.3%, p = 0.080). There was a significant interaction between stent type and gender regarding neointimal obstruction (p = 0.001) and maximum CSN (p = 0.003). Multivariate linear regression analysis revealed that female gender was independently associated with lower neointimal obstruction (p = 0.027) and maximum CSN (p = 0.004) for ZES but not for BMS. Compared to BMS, ZES were independently associated with a reduced risk for binary restenosis in both genders (odds ratio for women 0.003, p = 0.001; odds ratio for men 0.191, p <0.001), but the magnitude of this risk reduction with ZES was significantly greater in women than men (p = 0.015). In conclusion, female gender is independently associated with decreased neointimal hyperplasia in patients treated with ZES. The magnitude of risk reduction for binary restenosis with ZES is significantly greater in women than in men.

Topics: Angioplasty, Balloon, Coronary; California; Coronary Restenosis; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Myocardial Infarction; Neointima; Prognosis; Prosthesis Design; Retrospective Studies; Risk Factors; Sex Distribution; Sex Factors; Sirolimus

To assess the efficacy of the sirolimus-eluting stent when implanted in smaller caliber vessels using three-dimensional intravascular ultrasound (IVUS) analysis.. One hundred and twenty-three patients (69 sirolimus-coated Bx Velocity and 54 control) who underwent successful three-dimensional IVUS at follow up comprised this IVUS substudy from the SIRIUS (SIRolImUS-coated Bx Velocity stent in the treatment of patients with de novo coronary artery lesions) population. To evaluate the impact of vessel size, 2 groups were created using QCA reference vessel diameter (RVD; large vessel group: RVD>/=2.75 mm and small vessel group: RVD<2.75 mm).. Sirolimus-eluting stents significantly reduced neointimal hyperplasia by the same relative magnitude within the stent in small vessels as well as in large vessels. Although sirolimus-eluting stents had favorable effects on lumen area at stent edges in larger vessels, the effect was less in smaller vessels, especially at the proximal edge. IVUS-detected adverse vessel response, such as late-acquired incomplete apposition, did not increase in smaller vessels even with relatively higher dose exposure.. Sirolimus-eluting stents showed inhibition of neointimal hyperplasia in small vessels compared to bare metal stents with no increase of vascular complications.

Topics: Angioplasty, Balloon, Coronary; Coronary Artery Disease; Coronary Restenosis; Drug-Eluting Stents; Humans; Hyperplasia; Imaging, Three-Dimensional; Immunosuppressive Agents; Sirolimus; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

We designed a randomized trial exploiting optical coherence tomography (OCT) to assess coverage and apposition of overlapping bare-metal stents (BMS) and drug-eluting stents (DES) in human coronary arteries.. Overlapping DES impair healing in animals. Optical coherence tomography allows accurate in vivo assessment of stent strut coverage and apposition.. Seventy-seven patients with long coronary stenoses were randomized to overlapping sirolimus-eluting stents (SES), paclitaxel-eluting stents (PES), zotarolimus-eluting stents (ZES), or BMS. The primary goal of the study was to determine the rate of uncovered/malapposed struts in overlap versus nonoverlap segments, according to stent type, at 6-month follow-up with OCT.. A total of 53,047 struts were analyzed. The rate of uncovered/malapposed struts was 1.5 +/- 3.4% and 0.6 +/- 2.7% in overlap versus nonoverlap BMS (p = NS), respectively, and 4.3 +/- 11% and 3.6 +/- 8% in overlap versus nonoverlap DES (p = NS), respectively. There were no differences in the rates of uncovered/malapposed struts between overlapping BMS and DES, likely due to low frequency of uncovered/malapposed struts in ZES (0.1 +/- 0.4%), which offset the higher rates observed in SES (6.7 +/- 9.6%) and PES (6.7 +/- 16.5%, p < 0.05). Overlap segments showed greater neointimal volume obstruction versus nonoverlap segments in all DES (p < 0.05 for all DES types). Strut-level neointimal thickness at overlap and nonoverlap segments were lowest in SES (0.16 +/- 0.1 mm and 0.12 +/- 0.1 mm, respectively) compared with PES (0.27 +/- 0.1 mm and 0.20 +/- 0.1 mm, respectively), ZES (0.40 +/- 0.16 mm and 0.33 +/- 0.13 mm, respectively), and BMS (0.55 +/- 0.31 mm and 0.53 +/- 0.25 mm, respectively, p < 0.05).. As assessed by OCT the impact of DES on vascular healing was similar at overlapping and nonoverlapping sites. However, strut malapposition, coverage pattern, and neointimal hyperplasia differ significantly according to DES type. (Optical Coherence Tomography for Drug Eluting Stent Safety [ODESSA]; NCT00693030).

Topics: Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Angiography; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Feasibility Studies; Female; Humans; Hyperplasia; Male; Metals; Middle Aged; Paclitaxel; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Sirolimus; Stents; Time Factors; Tomography, Optical Coherence; Treatment Outcome; Ultrasonography, Interventional

Previous studies suggested that asymmetric stent expansion did not affect suppression of neointimal hyperplasia (NIH) after sirolimus-eluting stents (SES) implantation. The aim of this study was to evaluate the effects of stent eccentricity (SE) on NIH between SES versus paclitaxel-eluting stents (PES) using an intravascular ultrasound (IVUS) analysis from the randomized trial.. Serial IVUS data were obtained from Post-stent Optimal Expansion (POET) trial, allocated randomly to SES or PES. Three different SE (minimum stent diameter divided by maximum stent diameter) were evaluated; SE at the lesion site with maximal %NIH area (SE-NIH), SE at the minimal stent CSA [SE-minimal stent area (SE-MSA)], and averaged SE through the entire stent (SE-mean). We classified each drug-eluting stents (DES) into the concentric (≥ mean SE) and eccentric groups (< mean SE) based on the mean value of SE.. Among 301 enrolled patients, 233 patients [SES (n = 108), PES (n = 125)] underwent a follow-up IVUS. There was no significant correlation between %NIH area and SE-NIH (r = - 0.083, p = 0.391) or SE-MSA (r = - 0.109, p = 0.259) of SES. However, SE-NIH of PES showed a weak but significant correlation with %NIH area (r = 0.269, p < 0.01). As to the associations between SEmean and NIH volume index, SES revealed no significant correlation (r = - 0.001, p = 0.990), but PES showed a weak but significant correlation (r = 0.320, p < 0.01). However, there was no difference in the restenosis rate between the eccentric versus concentric groups of both DES.. This study suggests that lower SE of both SES and PES, which means asymmetric stent expansion, may not be associated with increased NIH.

Topics: Aged; Angiography; Coronary Restenosis; Drug-Eluting Stents; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Paclitaxel; Sirolimus; Tunica Intima; Ultrasonography, Interventional

To investigate the mechanistic basis underlying antirestenosis and the antiatherogenic effect of pioglitazone in patients with type 2 diabetes mellitus who were undergoing zotarolimus-eluting stent implantation.. Recent studies highlight the beneficial effect of pioglitazone in attenuating neointimal growth after stent implantation. Patients with coronary artery diseases were randomly assigned to pioglitazone (n=47) or placebo (n=47) after stent implantation. Pioglitazone significantly reduced neointimal hyperplasia within the stented lesion and attenuated total plaque burden in the in-segment regions of the stent, as assessed by intravascular ultrasonography at the 8-month follow-up. These changes were preceded by reduced circulating natural killer (NK) cells, diminished interleukin 6 and monocyte chemoattractant protein-1 levels, and downregulation of chemokine receptor 2 at 2 days after stent implantation; and an elevated interleukin 10 level at 10 days after implantation. Furthermore, the proliferation and migration of vascular smooth muscle cells were inhibited in the presence of pioglitazone-treated patient serum, demonstrating that the antiproliferative effects of pioglitazone occurred concurrently with its antiinflammatory action.. Our data present early cellular and immunologic changes by pioglitazone that might have been associated with antirestenotic and antiatherogenic effects in diabetic patients. Inhibiting proinflammatory responses while promoting antiinflammatory circuits, together with an antiproliferative action, may, in part, account for the antirestenotic effect of pioglitazone by altering vascular remodeling processes in the early phase.

Topics: Adult; Aged; Angioplasty, Balloon, Coronary; Biomarkers; Blood Glucose; Cardiovascular Agents; Cell Movement; Cell Proliferation; Cells, Cultured; Chemokine CCL2; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug-Eluting Stents; Female; Glycated Hemoglobin; Humans; Hyperplasia; Hypoglycemic Agents; Inflammation Mediators; Insulin; Interleukin-6; Killer Cells, Natural; Lipids; Male; Middle Aged; Myocytes, Smooth Muscle; Pioglitazone; Prospective Studies; Prosthesis Design; Receptors, CCR2; Republic of Korea; Single-Blind Method; Sirolimus; Thiazolidinediones; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Sirolimus-eluting stents (SES) have been shown to reduce intimal hyperplasia (IH) within the stent. Although angiographic studies have suggested focal distribution of IH, these data are limited by its spatial resolution and the minimal amount of IH. Therefore, the exact distribution pattern of SES IH remains unclear. Ninety-six SIRIUS trial patients who underwent SES (51) or bare metal stent (45) implantation and three-dimensional IVUS at 8 months follow-up were enrolled. Neointimal area (stent-lumen area) was obtained at every 0.5-mm interval throughout the stented segment. The length of each stent with IVUS-detectable neointima was determined and divided by the stented length in each case to normalize the data. Even with IVUS, IH was detectable in very limited SES stented segments (median 8% of total stented length) compared to the diffuse nature of IH within BMS with only 5 stented lesions having segments free from IH. In 25% (13 of 51) of patients, no IH was detectable within whole SES stented segments. In conclusion, SES has reduced not only the total amount of IH, but also limited the distribution. These data suggest that local conditions (heterogeneity of biological responses of particular plaques, pharmacokinetics, or their combination) may play a role in IH following SES implantation.

Topics: Angioplasty, Balloon, Coronary; Coronary Artery Disease; Drug-Eluting Stents; Humans; Hyperplasia; Immunosuppressive Agents; Sirolimus; Tunica Intima; Ultrasonography, Interventional

We tested two novel drug-eluting stents (DES), covered with a biodegradable-polymer carrier and releasing paclitaxel or sirolimus, which were compared against a bare metal stent (primary objective). The DES differed by the drug, but were identical otherwise, allowing to compare the anti-restenosis effects of sirolimus versus paclitaxel (secondary objective).. The efficacy of novel DES with biodegradable polymers should be tested in the context of randomized trials, even when using drugs known to be effective, such as sirolimus and paclitaxel.. Overall, 274 patients with de novo coronary lesions in native vessels scheduled for stent implantation were randomly assigned (2:2:1 ratio) for the paclitaxel (n = 111), sirolimus (n = 106), or bare metal stent (n = 57) groups. Angiographic follow-up was obtained at 9 months and major cardiac adverse events up to 12 months.. Both paclitaxel and sirolimus stents reduced the 9-month in-stent late loss (0.54-0.44 mm, 0.32-0.43 mm, vs. 0.90-0.45 mm respectively), and 1-year risk of target vessel revascularization and combined major adverse cardiac events (P < 0.05 for both, in all comparisons), compared with controls. Sirolimus stents had lower late loss than paclitaxel stents (P < 0.01), but similar 1-year clinical outcomes. There were no differences in the risk of death, infarction, or stent thrombosis among the study groups.. Both novel DES were effective in reducing neointimal hyperplasia and 1-year re-intervention, compared to bare metal stents. Our findings also suggest that sirolimus is more effective than paclitaxel in reducing angiographic neointima, although this effect was not associated with better clinical outcomes.

Topics: Aged; Angioplasty, Balloon, Coronary; Brazil; Cardiovascular Agents; Cardiovascular Diseases; Coated Materials, Biocompatible; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Drug-Eluting Stents; Female; Humans; Hyperplasia; Kaplan-Meier Estimate; Male; Metals; Middle Aged; Myocardial Infarction; Paclitaxel; Proportional Hazards Models; Prosthesis Design; Risk Assessment; Sirolimus; Stents; Thrombosis; Time Factors; Treatment Outcome

The aim of this study was to compare the vessel response between zotarolimus-eluting stents (ZES) and paclitaxel-eluting stents (PES) using intravascular ultrasound.. The ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial was a randomized controlled study of zotarolimus-eluting, phosphorylcholine-coated, cobalt-alloy stents for the treatment of de novo coronary lesions compared with using PES for the same treatment.. Data were obtained from patients with serial (baseline and 8-months follow-up) intravascular ultrasound analysis available (n = 198). Volumetric analysis was performed for vessel, lumen, plaque, stent, and neointima. Cross-sectional narrowing (given as percentage) was defined as neointimal area divided by stent area. Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. Subsegment analysis was performed at every matched 1-mm subsegment throughout the stent.. At follow-up, the ZES group showed significantly greater percentage of neointimal obstruction (16.6 +/- 12.0% vs. 9.9 +/- 8.9%, p < 0.01) and maximum cross-sectional narrowing (31.8 +/- 16.1% vs. 25.2 +/- 14.9%, p < 0.01) with smaller minimum lumen area than the PES group did. However, the incidence of maximum cross-sectional narrowing >50% was similar in the 2 groups. Neointima-free frame ratio was significantly lower in the ZES group. In overall analysis, whereas the PES group showed positive remodeling during follow-up (13.7 +/- 4.2 mm(3)/mm to 14.3 +/- 4.3 mm(3)/mm), the ZES group showed no significant difference (12.7 +/- 3.6 mm(3)/mm to 12.9 +/- 3.5 mm(3)/mm). In subsegment analysis, significant focal positive vessel remodeling was observed in 5% of ZES and 25% of PES cases (p < 0.05).. There were different global and focal vessel responses for ZES and PES. Both drug-eluting stents showed a similar incidence of lesions with severe narrowing despite ZES having a moderate increase in neointimal hyperplasia compared with neointimal hyperplasia in PES. There was a relatively lower neointima-free frame ratio in ZES, suggesting a greater extent of neointimal coverage. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269).

Topics: Aged; Alloys; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coated Materials, Biocompatible; Cobalt; Coronary Artery Disease; Coronary Restenosis; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Phosphorylcholine; Prosthesis Design; Single-Blind Method; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional; United States

The RESOLUTE trial examined the safety and efficacy of a next-generation zotarolimus-eluting coronary stent, Resolute (Medtronic CardioVascular Inc., Santa Rosa, California).. Revascularization benefits associated with current drug-eluting stents are often diminished in the presence of complex coronary lesions and in certain patient cohorts. Resolute uses a new proprietary polymer coating that extends the duration of drug delivery to match the longer healing duration often experienced in more complex cases.. The RESOLUTE trial was a prospective, nonrandomized, multicenter study of the Resolute stent in 139 patients with de novo coronary lesions with reference vessel diameters > or =2.5 and < or =3.5 mm and lesion length > or =14 and < or =27 mm. The primary end point was 9-month in-stent late lumen loss by quantitative coronary angiography. Secondary end points included major adverse cardiac events (MACE) at 30 days, 6, 9, and 12 months; acute device, lesion, and procedure success; and 9-month target vessel failure (TVF), target lesion revascularization (TLR), stent thrombosis, neointimal hyperplastic (NIH) volume, and percent NIH volume obstruction.. The 9-month in-stent late lumen loss was 0.22 +/- 0.27 mm. Cumulative MACE were 4.3%, 4.3%, 7.2%, and 8.7% at 30 days, 6, 9, and 12 months, respectively. Acute lesion, procedure, and device success rates were 100.0%, 95.7%, and 99.3%, respectively. At 9 months, TLR was 0.0%, TVF was 6.5%, stent thrombosis was 0.0%, NIH volume was 6.55 +/- 7.83 mm(3), and percent NIH volume obstruction was 3.73 +/- 4.05%.. In this feasibility study, the Resolute stent demonstrated low in-stent late lumen loss, minimal neointimal hyperplastic ingrowth, low TLR, no stent thrombosis, and acceptable TVF and MACE. (The RESOLUTE Clinical Trial; NCT00248079).

Topics: Aged; Angioplasty, Balloon, Coronary; Australia; Cardiovascular Agents; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Drug-Eluting Stents; Feasibility Studies; Female; Humans; Hyperplasia; Kaplan-Meier Estimate; Male; Middle Aged; Myocardial Infarction; New Zealand; Prospective Studies; Prosthesis Design; Sirolimus; Thrombosis; Time Factors; Treatment Outcome; Ultrasonography, Interventional; United States

The newly developed Nobori coronary stent coated with a bioresorbable polymer, polylactic acid, and the antiproliferative agent Biolimus A9 has the potential to reduce restenosis by suppressing neointima formation.. We conducted a randomized (2:1), controlled trial comparing the Biolimus A9-eluting stent Nobori and the paclitaxel-eluting stent Taxus Liberté, in 243 patients (153 Nobori and 90 Taxus) at 29 centers in Europe, Asia, and Australia. Patients with previously untreated lesions in up to 2 native coronary arteries were considered for enrollment. The primary end point was in-stent late loss at 9 months, whereas secondary end points included other quantitative coronary angiography parameters, such as in-segment late loss and the rate of restenosis as well as key intravascular ultrasound parameters. Clinical secondary end points were stent thrombosis and composite of major adverse cardiac events comprising death, myocardial infarction, and target vessel revascularization. At 9 months, the in-stent late loss was significantly lower in the Nobori group compared with the Taxus group (0.11+/-0.30 mm versus 0.32+/-0.50 mm) reaching both the primary hypothesis of noninferiority of Nobori stent versus Taxus Liberté stent (P<0.001) and the secondary hypothesis of superiority (P=0.001). This finding was confirmed by a significant reduction in binary restenosis from 6.2% in Taxus to 0.7% in Nobori (P=0.02) and neointimal volume obstruction, detected by intravascular ultrasound, from 5.5+/-7.2% in Taxus to 1.8+/-5.2% in Nobori (P=0.01). The major adverse cardiac events rate was 4.6% in the Nobori and 5.6% in the Taxus cohort of patients. The stent thrombosis rate was 0% in the Nobori arm and 4.4% in the Taxus arm.. The NOBORI 1 clinical trial confirmed its primary hypothesis--noninferiority of the Nobori Biolimus A9-eluting stent versus the Taxus Liberté stent in reducing neointimal proliferation. Both stents showed a low major adverse cardiac events rate in the studied population.

Topics: Angioplasty, Balloon, Coronary; Asia; Australia; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Europe; Female; Humans; Hyperplasia; Male; Middle Aged; Myocardial Infarction; Paclitaxel; Prospective Studies; Risk Assessment; Sirolimus; Thrombosis; Time Factors; Treatment Outcome; Ultrasonography, Interventional

To evaluate effects of sirolimus-eluting stents (SES) compared to bare-metal stents (BMS) at stent edges in patients with acute myocardial infarction (AMI).. Clinical, angiographic, intravascular ultrasound (lVUS) and virtual histology (VH)-IVUS results were obtained and analysed in 20 SES and 20 BMS AMI patients at the index procedure and at nine months follow-up. Quantitative angiography and IVUS showed a trend toward decreases in mean lumen diameter, vessel volume, minimum lumen area and mean lumen area at both stent edges of BMS, and at the proximal edge of SES. At the distal stent edge, a significant difference between BMS and SES treated patients in mean lumen area was found (D-0.8+/-1.6 mm2 versus D0.2+/-0.8 mm2 respectively, p=0.04). Furthermore, in-stent SES had a larger lumen volume (SES: 167.7+/-59.2 mm3 versus BMS: 125.1+/-43.8 mm3; p=0.02) and less neointima volume (7.3+/-9.1 mm3 versus 53.2+/-35.1 mm3; p<0.001). Neither SES nor BMS demonstrated a significant effect on plaque composition at follow-up VH-IVUS analysis.. A significant difference between SES and BMS treated patients was observed with respect to mean lumen diameter distal to the stented segment which suggests a downstream effect of sirolimus elution.

Topics: Adult; Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Metals; Middle Aged; Myocardial Infarction; Prosthesis Design; Sirolimus; Stents; Time Factors; Treatment Outcome; Ultrasonography, Interventional

Diabetes has been reported as an independent predictor of restenosis after drug-eluting stent implantation. The purpose of this study was to assess the long-term impact of increased drug dose in sirolimus-eluting stents (SES) on neointimal hyperplasia (NIH) in diabetic patients using volumetric intravascular ultrasound analysis.. The 3D trial is a multicenter, prospective, randomized, feasibility study of double-dose (280 microg/cm2) or conventional single-dose (140 microg/cm2) SES for the treatment of de novo coronary lesions in diabetic patients. To evaluate long-term efficacy, complete serial volumetric analyses (baseline, 6-month and 2-year follow up) were performed in 39 diabetic patients (17 single-dose, 22 double-dose). Each volume was divided by stent length to acquire volume index, expressed as mm3/mm. Percent neointimal volume was calculated as (neointimal volume/stent volume) x 100 at follow up.. Volumetric analysis showed similar results over time between the 2 stent groups (p = NS for all). At 2-year follow up, minimal increases in NIH area and percent NIH were observed in both groups, which translated into a decrease in lumen volume index compared to baseline (p < 0.05 for all). No late-acquired incomplete stent apposition was observed in either group.. The current single dose of sirolimus in SES is effective in inhibiting NIH in diabetic patients up to 2 years. In this patient subset, double-dose SES did not confer additional NIH suppression at 2-year follow up compared to conventional single-dose SES.

Topics: Blood Vessel Prosthesis Implantation; Coronary Restenosis; Diabetic Angiopathies; Dose-Response Relationship, Drug; Drug-Eluting Stents; Feasibility Studies; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Prospective Studies; Sirolimus; Tunica Intima; Ultrasonography, Interventional

Patients with diabetes have increased risk of in-stent restenosis after coronary stent implantation owing to neointimal hyperplasia (NIH). The aim of the study was to evaluate the extent and distribution of NIH with intravascular ultrasound (IVUS) after coronary artery stenting with sirolimus-eluting (Cypher) or paclitaxel-eluting (Taxus) stents in diabetic patients.. One hundred and thirty diabetic patients were randomized to Cypher or Taxus stent implantation. IVUS was performed at 8 month follow-up. NIH volume was significantly reduced in the Cypher group when compared with the Taxus group: median (inter-quartile range) 0.0 (0.0-0.0) vs. 8.0 mm(3) (0.1-33.0), P < 0.001. Per cent NIH volume was also significantly lower in Cypher stents compared with Taxus stents: median (inter-quartile range) 0.0 (0.0-0.0) vs. 7.5% (0.1-27.0), P < 0.001. NIH was covering 5.4% of the stent length in the Cypher stents compared with 46.1% in the Taxus stents (P < 0.001). The incidence of diffuse NIH was significantly higher for Taxus than for Cypher stents (42.9 vs. 3.5%, P < 0.001). Taxus stents had more often NIH at the proximal stent edge compared with Cypher stents (45.1 vs. 7%, P < 0.001) and no Cypher stents had NIH at the distal stent edge compared with 35.5% of the Taxus stents (P < 0.001).. In diabetic patients, the Cypher stent, compared with the Taxus stent, inhibited NIH more effectively and had a more focal NIH pattern including less involvement of the stent edges.

Topics: Angioplasty, Balloon, Coronary; Coronary Restenosis; Coronary Vessels; Diabetic Angiopathies; Drug-Eluting Stents; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Paclitaxel; Sirolimus; Treatment Outcome; Tunica Intima; Ultrasonography

The aim of this study was to examine the impact of overlapping bare-metal stent (BMS) and three different formulations of drug-eluting stent (DES) on intimal hyperplasia (IH) response of patients with diabetes mellitus (DM).. Forty-nine DM patients treated with overlapping BMS (19 lesions), sirolimus-eluting stent (SES 12 lesions), paclitaxel-eluting stent (PES 8 lesions) or tacrolimus-eluting stent (TES 10 lesions) were studied. Baseline and 9-month follow-up volumetric intravascular vascular ultrasound (IVUS) and quantitative coronary angiography (QCA) analysis were performed in the entire stented segment and in the overlapped (OL) and non-overlapped (non-OL) subsegments. Clinical outcomes were evaluated at 1-year follow-up.. Post-procedure (PO-) QCA measurements were similar in all stent groups, and between OL and non-OL subsegments in each individual type of stents. Percent IH was lower in SES and PES vs. BMS (p < 0.05). Percent IH was significantly greater in OL subsegment compared with non-OL subsegment in BMS (p < 0.05), but not in all type of DES groups. SES showed significantly less %IH compared with PES and TES in OL and non-OL subsegments. Vessel area at the OL remained unchanged from PO to FU in all type of DES and BMS groups. There were no aneurysm formation and no stent thrombosis up to 1-year follow-up.. Overlapping BMS is associated with enhanced IH response in diabetic patients, whereas overlapping DES, particularly SES and PES, appear effective to inhibit IH without detectable late vascular adverse effects.

Topics: Analysis of Variance; Coronary Angiography; Coronary Disease; Diabetes Complications; Drug-Eluting Stents; Female; Humans; Hyperplasia; Imaging, Three-Dimensional; Male; Paclitaxel; Prospective Studies; Sirolimus; Stents; Tacrolimus; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Wall shear stress (WSS) has been associated with neointimal hyperplasia (NIH) following bare metal stent (BMS) implantation. Drug-eluting stents (DES) almost abolish NIH. Conversely, diabetes mellitus amplifies NIH response. The association between WSS and arterial wall response following DES and BMS implantation in diabetic patients remains to be evaluated.. The study involved 20 diabetic patients randomized to BMS (n = 9) or sirolimus-eluting stent (SES; n = 11) implantation in native coronary arteries. A computational fluid dynamic model applied 3D intravascular ultrasound (IVUS) and two-plane angiographic to measure WSS (Pa). IVUS assessments were performed post-procedure and at 9-months follow-up. The target segment encompassed the stent plus 5 mm distal and proximal edges. A total of 93 subsegments were evaluated: in-stent segments divided in three subsegments (proximal, mid and distal; n = 60) and proximal and distal edges (n = 33).. Stent length was similar between BMS (17.4 +/- 7.3 mm) and SES (19.8 +/- 6.8 mm) groups. NIH was observed in all BMS subsegments (n = 27) versus one subsegment in the SES group (n = 33). WSS ranged from 0.52 to 4.20 Pa in the BMS and from 0.42 to 3.06 Pa in the SES group. There was no correlation between WSS and NIH in either stent group. In addition, there were no correlation between the change of external elastic membrane (EEM) or plaque growth at the edges and WSS.. WSS was not associated with NIH after implantation of SES or BMS in diabetic patients. Plaque growth or the change of EEM at the edges were not associated with WSS either.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Computer Simulation; Coronary Angiography; Coronary Circulation; Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Diabetic Angiopathies; Drug-Eluting Stents; Female; Hemorheology; Humans; Hyperplasia; Image Interpretation, Computer-Assisted; Imaging, Three-Dimensional; Male; Metals; Middle Aged; Models, Cardiovascular; Pulsatile Flow; Sirolimus; Stents; Stress, Mechanical; Time Factors; Treatment Outcome; Ultrasonography, Interventional

The goal of this work was to verify whether the superiority of the sirolimus-eluting stent (SES) in inhibiting neointimal hyperplasia could be demonstrated in complex coronary lesions.. Both the SES (Cypher, Cordis, Miami Lakes, Florida) and the paclitaxel-eluting stent (PES) (Taxus, Boston Scientific, Natick, Massachusetts) have shown a marked reduction in neointimal hyperplasia compared with bare-metal stents. Intravascular ultrasound (IVUS) is the best method to assess arterial response to stent deployment, but few IVUS data are available comparing complex lesions treated with SES or PES.. We prospectively randomized patients with complex lesions to SES or PES implantation. Intravascular ultrasound and quantitative angiography were performed post-procedure and at 9 months. Mean neointimal hyperplasia area (NIHA), percent of NIHA (NIHA%), mean peristent plaque area (PSPA), and percent of PSPA (PSPA%) were calculated. The primary end point was NIHA% at follow-up. Secondary end points included change in PSPA% and angiographic late luminal loss at follow-up.. Of the 100 patients enrolled, 42 receiving the SES and 43 receiving the PES had adequate IVUS assessment. Vessel, plaque, and lumen areas were comparable at follow-up, but NIHA% was significantly lower with SES than PES (7.4 +/- 4.2% vs. 15.4 +/- 8.1%; p < 0.001). A significant reduction in PSPA% was observed with SES (-4 +/- 10% vs. 0 +/- 8%; p = 0.01). Late loss was significantly lower with SES (0.16 +/- 0.19 mm vs. 0.32 +/- 0.33 mm; p = 0.003).. The SES shows a significantly higher inhibition of neointimal hyperplasia compared with PES in complex lesions. However, both stents have excellent IVUS and angiographic results at 9 months. A significant reduction in peri-stent plaque is observed only with SES.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Stenosis; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Paclitaxel; Radiography; Sirolimus; Stents; Tubulin Modulators; Tunica Intima; Ultrasonography, Interventional

Using serial intravascular ultrasound (IVUS), the efficacy of reduced-dose sirolimus-eluting stents (SESs) in the prevention of neointimal hyperplasia (NH) and maintenance of luminal patency in human coronary arteries was evaluated.. In the animal model, a broad therapeutic window regarding sirolimus doses in suppressing NH has been reported.. Serial cross-sectional and volumetric IVUS analyses were performed in 44 patients treated with SES that contained lower sirolimus doses (either 45% or 70%) than standard SES. For cross-sectional analysis, minimum lumen area (MLA) was measured. Percent (%) NH volumetric obstruction was calculated as 100 x NH volume/stent volume.. IVUS measurements were similar between the two drug-dose groups. At 12 months follow-up, only one case developed late incomplete stent apposition. Between 4 and 12 months, a slight increase of in-stent % area loss and % NH obstruction was noted (3.5% +/- 10.4% to 6.7% +/- 10.7% and 1.9% +/- 5.0% to 4.4% +/- 8.0%, respectively). The majority of studied cases, however, sustained less than a 10% volumetric (93% of studied cases) and area loss (75% of studied cases) in the stented segment up to 12 months. At 12 months, % area loss within the stented segments and 5-mm reference segments were comparable (7.0% +/- 19.6% versus 6.7% +/- 10.7%).. Although slight increases of NH were noted, SESs, delivering two reduced drug doses, appeared to be effective for maintaining luminal patency during 12 months follow-up.

Topics: Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Dose-Response Relationship, Drug; Drug-Eluting Stents; Humans; Hyperplasia; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional; Vascular Patency

The results of 2 randomized controlled trials of the Endeavor zotarolimus-eluting stent (ZES; Medtronic Vascular, Santa Rosa, CA) were recently reported: ENDEAVOR II, in which the Endeavor stent was compared with the Driver bare metal stent (BMS; Medtronic Vascular), and ENDEAVOR III, in which the Endeavor stent was compared with the first-generation Cypher sirolimus-eluting stent (SES; Cordis Corporation, Miami Lakes, FL). To examine in detail the vascular responses to the Endeavor stent, serial intravascular ultrasound (IVUS) analyses were performed in subsets of patients in the 2 trials at baseline and 8-month follow-up. The investigators report results for various IVUS parameters and compare those with published results for the first-generation SES and paclitaxel-eluting stent (PES). The ZES demonstrated significantly improved effectiveness and equivalent safety compared with the BMS in ENDEAVOR II. Although the ZES seems to be slightly less effective at inhibiting intimal hyperplasia than the SES and PES, early results are indicative of an acceptable safety profile. This finding may be due in part to the relatively complete and uniform neointimal coverage associated with the ZES.

Topics: Anti-Bacterial Agents; Coronary Disease; Double-Blind Method; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Tunica Intima; Ultrasonography

The aim of this intravascular ultrasound (IVUS) study was to assess the efficacy of the AXXESS Plus stent system for the treatment of bifurcation coronary lesions.. The AXXESS Plus is a novel bifurcation drug-eluting stent, comprised of a self-expanding flare-shaped stent platform and bioabsorbable polymer coating that releases Biolimus A9.. Data were obtained from the AXXESS PLUS trial, a prospective, multicenter, nonrandomized, single-arm study to evaluate safety and efficacy. Six-month follow-up IVUS analysis was available in 49 cases. Volumetric analysis using Simpson's method within the AXXESS stent, and cross-sectional analysis at the ostium of main branch and/or side branch was performed. Impact of bifurcation angle on stent expansion at the carina was also evaluated.. Within the AXXESS stent, neointimal volume obstruction percentage was 2.3% +/- 2.2%, with a minimum lumen area of 7.9 +/- 2.6 mm(2). Lumen area was 5.2 +/- 1.7 mm(2) at main branch ostium, and 4.0 +/- 1.5 mm(2) at side branch ostium. In two cases, incomplete stent apposition was observed at the proximal edge of the AXXESS stent. In one case, a gap between the AXXESS stent and an additional stent was observed. Greater bifurcation angle inversely correlated with smaller stent area at side branch ostium (r = -0.54, P = 0.03) but not at main branch ostium (r = -0.2, P = 0.29).. This novel self-expanding, drug-eluting bifurcation stent demonstrated effective lesion coverage along with significant neointimal suppression equivalent to current generation balloon-expandable drug-eluting stent technology.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Prospective Studies; Prosthesis Design; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

The aim of this study was to assess neointimal hyperplasia following sirolimus-eluting (SES) and paclitaxel-eluting stents (PES) implantation in a patients with complex coronary disease.. Between January to December 2004, 70 patients were enrolled in this study (SES = 37; PES = 33. The primary objective was to assess the efficacy of SES and PES on neointimal proliferation inhibition in patients with complex coronary lesions by volumetric 3D intravascular ultrasound (IVUS) assessment at six-month follow-up.. Baseline clinical, demographic or angiographic characteristics were well balanced in both groups. All procedures as well as hospitalisation were uneventful. The percentage of B2/C lesions in our study was > 90% in both groups. The IVUS-assessed in-stent mean neointimal hyperplasia volume was significantly lower in lesions treated with SES compared to PES (4.1 +/- 11 mm3 vs. 17.4 +/- 23 mm3, p < 0.002) at 6 month follow-up. No difference in both MACE (3.0 versus 6.0%, p = NS) and restenosis (5.4 versus 9.1%, p = NS) were found. The in-segment late loss at six month was 0.26 mm in the SES and 0.48 mm in the PES group (p = NS).. The present study showed reduced neointimal proliferation after sirolimuseluting as compared to paclitaxel-eluting stents in patients with complex coronary artery disease. Both SES and PES were associated with low rate of angiographic restenosis or major adverse cardiovascular events.

Topics: Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Artery Disease; Drug Delivery Systems; Female; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Prospective Studies; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional; Vascular Patency

A predefined intravascular ultrasound (IVUS) substudy was performed to evaluate the vascular effects of sirolimus-eluting stent (SES) versus bare-metal stent (BMS).. The Diabetes and Sirolimus-Eluting Stent (DIABETES) trial is a prospective, multicenter, randomized, controlled trial aimed at demonstrating the efficacy of the SES compared with BMS in diabetic patients.. Serial intravascular ultrasound analyses were performed in 140 lesions (SES = 75; BMS = 65) immediately after stent implantation and at nine-month follow-up. Vessel, luminal, and stent mean areas and volumes were evaluated at both edges and within the stented segment. Qualitative assessment of residual dissections and stent apposition were also performed.. Baseline clinical and angiographic characteristics were similar between groups. At 9 months, in-stent neointimal hyperplasia (NIH) mean area and volume were significantly reduced in the SES group (median NIH area 0.01 mm2 [0.0 to 0.1] vs. 2.0 mm2 [1.0 to 2.9] and median NIH volume 0.11 mm3 [0 to 2.1] vs. 35.3 mm3 [16.6 to 62.6]; both p < 0.0001). In the SES group, stent edges evidenced significant increase in lumen dimensions mainly due to significant increase in vessel volume, whereas those of the BMS group presented vessel shrinkage leading to significant lumen reduction. Late acquired incomplete stent apposition was observed in 11 lesions (14.7%) in the SES group and 0 in the BMS group (p = 0.001). At one year, no stent thromboses occurred in malapposed stents.. The SES implantation effectively inhibits NIH in diabetic patients. The antirestenotic effect of SES is also appreciated at the stent edges. Late acquired stent malapposition is a frequent phenomenon in diabetic patients treated with SES.

Topics: Aged; Coronary Angiography; Coronary Disease; Diabetic Angiopathies; Equipment Design; Female; Follow-Up Studies; Humans; Hyperplasia; Imaging, Three-Dimensional; Male; Metals; Middle Aged; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

The aim of the study was to compare the angioplasty mechanisms of drug (sirolimus)-eluting stent (DES) implantation and vascular brachytherapy (VBT) for the treatment of in-stent restenosis (ISR) as assessed by intravascular ultrasound (IVUS).. We performed IVUS in 53 patients (28 DES, 25 VBT) before and after angioplasty of ISR and at 6-month follow-up. Cross-sectional areas of the external elastic membrane, the stent, and the lumen were measured. Plaque + media, peristent plaque, and intimal hyperplasia areas were calculated, respectively.. Clinical and IVUS baseline characteristics did not differ between groups at baseline. After the index procedure, the lumen at the stent site was smaller in the DES group (DES 6.7 +/- 2.0 mm2 vs VBT 7.5 +/- 2.2 mm2, P = .042). Because of less intimal hyperplasia (DES 0.2 +/- 0.5 mm2 vs VBT 0.7 +/- 0.7 mm2, P = .043), the lumen dimensions revealed no difference between groups at follow-up (DES 6.5 +/- 2.3 mm2 vs VBT 6.8 +/- 2.2 mm2, P = .374). At the reference site, the index procedure led to a similar increase of plaque + media (DES 0.9 +/- 0.9 mm2 vs VBT 0.6 +/- 1.2 mm2, P = .150). At follow-up, the plaque + media was significantly smaller in the DES group (DES 8.0 +/- 6.6 mm2 vs VBT 9.9 +/- 7.8 mm2, P = .013).. Drug-eluting stent for the treatment of ISR more effectively inhibits neointima formation when compared with VBT. Yet insufficient stent expansion might be a reason for device failure and should be avoided. At the reference site, lumen loss by an increased plaque burden, as has been well recognized following VBT, is not present with DES.

Topics: Aged; Angioplasty, Balloon; Beta Particles; Brachytherapy; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug Implants; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Stents; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

The effect of lesion characteristics on neointimal hyperplasia after sirolimus-eluting stent implantation was examined in 45 patients who underwent successful preinterventional intravascular ultrasound. There were no differences in neointimal hyperplasia between the moderate/severe calcified lesion group (calcium arc >120 degrees ) and the non/mild calcified lesion group or between the positive vessel remodeling group (external elastic membrane area at the minimal lumen area site larger than that at the proximal reference site) and negative vessel remodeling group. No correlation between preinterventional plaque burden and neointimal hyperplasia was found. In patients who have coronary artery disease, sirolimus-eluting stents continue to demonstrate striking suppression of neointimal proliferation, irrespective of lesion characteristics previously associated with greater restenotic risk.

Topics: Blood Vessel Prosthesis Implantation; Coated Materials, Biocompatible; Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Disease Progression; Double-Blind Method; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Postoperative Complications; Prospective Studies; Prosthesis Failure; Risk Factors; Severity of Illness Index; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

The effectiveness of SES to reduce the risk of restenosis was initially demonstrated in short lesions using stent implantation with routine pre-dilatation and post-dilatation. This intravascular ultrasound (IVUS) substudy of the E-SIRIUS trial sought to evaluate local arterial responses to sirolimus-eluting stents (SES) delivered with a stent implantation technique allowing direct stenting and only selectively applying high-pressure post-dilatation.. IVUS was performed immediately after intervention and at 8-month follow-up in 51 patients randomised to either bare-metal stents (BMS; Bx-Velocitytrade mark; N=20) or SES (Cyphertrade mark N=31). Direct stenting was allowed (24%) and post-dilation was performed only selectively (32%). Lumen dimensions, intimal hyperplasia and vessel remodeling were compared between SES and BMS. Subsequently, results of SES in the E-SIRIUS IVUS substudy (N=31) were compared to those of SES in the IVUS substudy of the SIRIUS trial (N=137). SES in SIRIUS IVUS substudy were delivered with 100% pre-dilatation and 77% post-dilatation. Baseline stent and reference segment measurements were similar between BMS and SES in E-SIRIUS IVUS patients. Using SES there was a 96% reduction in intimal hyperplasia volume within the stented segment (1.8+/-4.9 vs 50.6+/-39.7 mm3, P<0.001) and a significantly larger minimal lumen cross sectional area at 8-month follow-up (4.5+/-1.1 vs 2.3+/-0.9 mm2, P<0.001). No vessel remodeling was observed with the use of SES. The applied stent implantation technique resulted in a minimal stent/reference vessel area ratio of 0.75+/-0.17 in E-SIRIUS SES as compared to 0.84+/-0.23 in SIRIUS SES (P=0.046). Mean intimal hyperplasia cross-sectional area at follow-up was 0.1+/-0.2 mm2 in the SES group of E-SIRIUS and 0.5+/-0.8 mm2 in the SES group of SIRIUS (P=0.003).. An implantation technique of SES which includes direct stenting and minimizes the use of high-pressure post-dilatation results in less optimal stent expansion. However, follow-up results compare very favourable to those of BMS and are characterised by even less intimal hyperplasia than after a more forceful implantation of SES.

Topics: Aged; Blood Vessel Prosthesis Implantation; Coated Materials, Biocompatible; Coronary Restenosis; Coronary Vessels; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Prosthesis Design; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

To assess whether asymmetric stent expansion affects suppression of neointimal hyperplasia after sirolimus-eluting stent implantation, 64 patients in the SIRolImUS-coated Bx Velocity stent trial who underwent single 18-mm stent implantation and 3-dimensional intravascular ultrasonography at 8-month follow-up were enrolled. To assess the longitudinal stent asymmetric expansion, 2 cross sections with a maximal/minimal stent area were chosen in each patient. To assess for tomographic stent asymmetric expansion, stent eccentricity was determined by dividing the minimum stent diameter by the maximum stent diameter. At the 2 cross sections with a maximal/minimal stent area, a sirolimus-eluting stent reduced neointimal hyperplasia significantly with no interaction between the treatment and stent areas. A sirolimus-eluting stent also significantly reduced neointimal hyperplasia in the concentric and eccentric stent groups.

Topics: Angioplasty, Balloon, Coronary; Blood Vessel Prosthesis Implantation; Coated Materials, Biocompatible; Coronary Stenosis; Double-Blind Method; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Postoperative Complications; Prospective Studies; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Patients with diabetes mellitus have less favourable outcomes after percutaneous coronary intervention (PCI) than non-diabetics. We performed a subgroup analysis of the multicentre RAVEL trial to examine the impact of the sirolimus-eluting stent (SES) on outcomes in diabetic patients. The RAVEL study randomized 238 patients to treatment with either sirolimus-eluting or bare metal stents. Forty-four patients were diabetic; 19 received sirolimus-eluting stents and 25 were treated with bare metal stents. The differences in outcomes between diabetic and non-diabetic patients treated with SES (n=101) were also assessed. Follow-up angiography was performed at 6 months. Major adverse cardiac events (MACE) defined as death, myocardial infarction (MI), or target lesion revascularization (TLR) were analysed at 12-month follow-up. Six-month in-stent late lumen loss was significantly lower for the diabetic SES than the bare stent group (0.07+/-0.2 vs 0.82+/-0.5mm; P<0.001) and similar to that in non-diabetics treated with SES (-0.03+/-0.27mm). There was zero restenosis in the SES groups (diabetic and non-diabetic) compared to a 42% rate in the diabetic population assigned to bare metal stents (P=0.001). After 12 months, there was one non-Q-wave MI and one non-cardiac death in the diabetic SES group, while 12 patients in the bare metal stent group had MACE (one death, two MI, nine TLR) (P=0.01)-an event-free survival rate of 90% vs 52%, respectively (P<0.01). There were no TLRs in both SES groups compared to 36% rate in the diabetic bare metal stent group (P=0.007). Conclusion Diabetics treated with SES were associated with a virtual abolition of neointimal proliferation and low event rates at long-term follow-up.

Topics: Coronary Restenosis; Coronary Stenosis; Diabetic Angiopathies; Disease-Free Survival; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Sirolimus; Stents; Tunica Intima

Everolimus, an active immunosuppressive and antiproliferative agent of the same family as sirolimus (rapamycin), has demonstrated significant reduction of neointimal proliferation in animal studies. The First Use To Underscore restenosis Reduction with Everolimus (FUTURE) I trial was the first in-human experience to evaluate the safety and efficacy of everolimus-eluting stents (EES), coated with a bioabsorbable polymer, compared with bare metal stents (BMS).. FUTURE I was a prospective, single-blind, randomized trial that enrolled 42 patients with de novo coronary lesions (EES 27, BMS 15). Patient and lesion characteristics were comparable between the groups. Major adverse cardiac event rates were low at 30 days and 6 months, without any early or late stent thrombosis for either group (P=NS). Between 6 and 12 months, there were no additional reports of major adverse cardiac events. The 6-month angiographic in-stent restenosis rate was 0% versus 9.1% (1 patient) (P=NS), with an associated late loss of 0.11 mm versus 0.85 mm (P<0.001), and the in-segment restenosis rate was 4% (1 patient) and 9.1% (1 patient) (P=NS) for EES and BMS, respectively. Intravascular ultrasound analysis revealed a significant reduction of percent neointimal volume in EES compared with BMS (2.9+/-1.9 mm3/mm versus 22.4+/-9.4 mm3/mm, P<0.001). There was no late stent malapposition in either group. The safety and efficacy of the EES appeared to be sustained at 12 months.. In this initial clinical experience, EES with bioabsorbable polymer demonstrated a safe and efficacious method to reduce in-stent neointimal hyperplasia and restenosis.

Topics: Aged; Anticoagulants; Catheterization; Cineangiography; Coated Materials, Biocompatible; Comorbidity; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Drug Implants; Everolimus; Female; Follow-Up Studies; Growth Inhibitors; Humans; Hyperplasia; Immunosuppressive Agents; Lactic Acid; Male; Middle Aged; Myocardial Infarction; Polyesters; Polymers; Prospective Studies; Single-Blind Method; Sirolimus; Stainless Steel; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Conventional sirolimus-eluting stent (SES) implantation typically follows balloon predilation. The impact of direct SES implantation on in-stent neointimal hyperplasia and the adjacent reference segments has not been evaluated. The aim of this study was to analyze direct and conventional SES implantation techniques by angiography and serial intravascular ultrasound. Fifty-three patients with single de novo coronary lesions underwent successful conventional (n = 26) and direct (n = 27) SES implantation. At 6-month follow-up, similar in-stent late luminal loss and decreased neointimal hyperplasia volume were seen in the 2 groups, preserving the luminal dimensions at the edges of the stents.

Topics: Angioplasty, Balloon, Coronary; Blood Vessel Prosthesis Implantation; Coronary Angiography; Coronary Vessels; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Outcome Assessment, Health Care; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

The goal of this intravascular ultrasound investigation was to provide a more detailed morphological analysis of the local biological effects of the implantation of a sirolimus-eluting stent compared with an uncoated stent.. In the RAVEL trial, 238 patients with single de novo lesions were randomized to receive either an 18-mm sirolimus-eluting stent (Bx VELOCITY stent, Cordis) or an uncoated stent (Bx VELOCITY stent). In a subset of 95 patients (sirolimus-eluting stent=48, uncoated stent=47), motorized intravascular ultrasound pullback (0.5 mm/s) was performed at a 6-month follow-up. Stent volumes, total vessel volumes, and plaque-behind-stent volumes were comparable. However, the difference in neointimal hyperplasia (2+/-5 versus 37+/-28 mm3) and percent of volume obstruction (1+/-3% versus 29+/-20%) at 6 months between the 2 groups was highly significant (P<0.001), emphasizing the nearly complete abolition of the proliferative process inside the drug-eluting stent. Analysis of the proximal and distal edge volumes showed no significant difference between the 2 groups in external elastic membrane or lumen and plaque volume at the proximal and distal edges. There was also no evidence of intrastent thrombosis or persisting dissection at the stent edges. Although there was a higher incidence of incomplete stent apposition in the sirolimus group compared with the uncoated stent group (P<0.05), it was not associated with any adverse clinical events at 1 year.. Sirolimus-eluting stents are effective in preventing neointimal hyperplasia without creating edge effect and without affecting the plaque burden behind the struts.

Topics: Blood Vessel Prosthesis Implantation; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Double-Blind Method; Drug Administration Routes; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional; Vascular Patency

Early results of sirolimus-eluting stent implantation showed a nearly complete abolition of neointimal hyperplasia. The question remains, however, whether the early promising results will still be evident at long-term follow-up. The objective of our study was to evaluate the efficiency of sirolimus-eluting stent implantation for up to 2 years of follow-up.. Fifteen patients with de novo coronary artery disease were treated with 18-mm sirolimus-eluting Bx-Velocity stents (Cordis) loaded with 140 microg sirolimus/cm2 metal surface area in a slow release formulation. Quantitative angiography (QCA) and intravascular ultrasound (IVUS) were performed according to standard protocol. Sirolimus-eluting stent implantation was successful in all 15 patients. During the in-hospital course, 1 patient died of cerebral hemorrhage after periprocedural administration of abciximab, and 1 patient underwent repeat stenting after 2 hours because of edge dissection that led to acute occlusion. Through 6 months and up to 2 years of follow-up, no additional events occurred. QCA analysis revealed no significant change in stent minimal lumen diameter or percent diameter stenosis, and 3-dimensional IVUS showed no significant deterioration in lumen volume. In 2 patients, additional stenting was performed because of significant lesion progression remote from the sirolimus-eluting stent.. Sirolimus-eluting stents showed persistent inhibition of neointimal hyperplasia for up to 2 years of follow-up.

Topics: Abciximab; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Blood Vessel Prosthesis Implantation; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Drug Implants; Female; Follow-Up Studies; Humans; Hyperplasia; Immunoglobulin Fab Fragments; Immunosuppressive Agents; Male; Middle Aged; Platelet Aggregation Inhibitors; Reoperation; Sirolimus; Stents; Time; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

The need for repeated treatment of restenosis of a treated vessel remains the main limitation of percutaneous coronary revascularization. Because sirolimus (rapamycin) inhibits the proliferation of lymphocytes and smooth-muscle cells, we compared a sirolimus-eluting stent with a standard uncoated stent in patients with angina pectoris.. We performed a randomized, double-blind trial to compare the two types of stents for revascularization of single, primary lesions in native coronary arteries. The trial included 238 patients at 19 medical centers. The primary end point was in-stent late luminal loss (the difference between the minimal luminal diameter immediately after the procedure and the diameter at six months). Secondary end points included the percentage of in-stent stenosis of the luminal diameter and the rate of restenosis (luminal narrowing of 50 percent or more). We also analyzed a composite clinical end point consisting of death, myocardial infarction, and percutaneous or surgical revascularization at 1, 6, and 12 months.. At six months, the degree of neointimal proliferation, manifested as the mean (+/-SD) late luminal loss, was significantly lower in the sirolimus-stent group (-0.01+/-0.33 mm) than in the standard-stent group (0.80+/-0.53 mm, P<0.001). None of the patients in the sirolimus-stent group, as compared with 26.6 percent of those in the standard-stent group, had restenosis of 50 percent or more of the luminal diameter (P<0.001). There were no episodes of stent thrombosis. During a follow-up period of up to one year, the overall rate of major cardiac events was 5.8 percent in the sirolimus-stent group and 28.8 percent in the standard-stent group (P<0.001). The difference was due entirely to a higher rate of revascularization of the target vessel in the standard-stent group.. As compared with a standard coronary stent, a sirolimus-eluting stent shows considerable promise for the prevention of neointimal proliferation, restenosis, and associated clinical events.

Topics: Coronary Disease; Coronary Restenosis; Coronary Vessels; Delayed-Action Preparations; Double-Blind Method; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Myocardial Infarction; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

We investigated the role of a sirolimus-embedded silk microneedle (MN) wrap as an external vascular device for drug delivery efficacy, inhibition of neointimal hyperplasia, and vascular remodeling. Using dogs, a vein graft model was developed to interpose the carotid or femoral artery with the jugular or femoral vein. The control group contained four dogs with only interposed grafts; the intervention group contained four dogs with vein grafts in which sirolimus-embedded silk-MN wraps were applied. After 12-weeks post-implantation, 15 vein grafts in each group were explanted and analyzed. Vein grafts applied with the rhodamine B-embedded silk-MN wrap showed far higher fluorescent signals than those without the wrap. The diameter of vein grafts in the intervention group decreased or remained stable without dilatation; however, it increased in the control group. The intervention group had femoral vein grafts with a significantly lower mean neointima-to-media ratio, and had vein grafts with an intima layer showing a significantly lower collagen density ratio than the control group. In conclusion, sirolimus-embedded silk-MN wrap in a vein graft model successfully delivered the drug to the intimal layer of the vein grafts. It prevented vein graft dilatation, avoiding shear stress and decreasing wall tension, and it inhibited neointimal hyperplasia.

Topics: Animals; Carotid Arteries; Dogs; Drug Delivery Systems; Hyperplasia; Neointima; Sirolimus

Intimal hyperplasia (IH) is a major cause of vascular restenosis after bypass surgery, which progresses as a series of processes from the acute to chronic stage in response to endothelial damage during bypass grafting. A strategic localized drug delivery system that reflects the pathophysiology of IH and minimizes systemic side effects is necessary. In this study, the sequential release of sirolimus, a mechanistic target of rapamycin (mTOR) inhibitor, and statin, an HMG-COA inhibitor, was realized as a silk fibroin-based microneedle device in vivo. The released sirolimus in the acute stage reduced neointima (NI) and vascular fibrosis through mTOR inhibition. Furthermore, rosuvastatin, which was continuously released from the acute to chronic stage, reduced vascular stiffness and apoptosis through the inactivation of Yes-associated protein (YAP). The sequential release of sirolimus and rosuvastatin confirmed the synergistic treatment effects on vascular inflammation, VSMC proliferation, and ECM degradation remodeling through the inhibition of transforming growth factor (TGF)-beta/NF-κB pathway. These results demonstrate the therapeutic effect on preventing restenosis with sufficient vascular elasticity and significantly reduced IH in response to endothelial damage. Therefore, this study suggests a promising strategy for treating coronary artery disease through localized drug delivery of customized drug combinations.

Topics: Animals; Cell Proliferation; Disease Models, Animal; Fibroins; Humans; Hyperplasia; Rosuvastatin Calcium; Sirolimus; TOR Serine-Threonine Kinases

Various preclinical studies with developed Eustachian tube (ET) stents are in progress but have not yet been clinically applied. ET stent is limited by stent-induced tissue hyperplasia in preclinical studies. The effectiveness of sirolimus-eluting cobalt-chrome alloy stent (SES) in suppressing stent-induced tissue hyperplasia after stent placement in the porcine ET model was investigated. Six pigs were divided into two groups (i.e., the control and the SES groups) with three pigs for each group. The control group received an uncoated cobalt-chrome alloy stent (n = 6), and the SES group received a sirolimus-eluting cobalt-chrome alloy stent (n = 6). All groups were sacrificed 4 weeks after stent placement. Stent placement was successful in all ETs without procedure-related complications. None of the stents was able to keep its round shape as original, and mucus accumulation was observed inside and around the stent in both groups. On histologic analysis, the tissue hyperplasia area and the thickness of submucosal fibrosis were significantly lower in the SES group than in the control group. SES seems to be effective in suppressing stent-induced tissue hyperplasia in porcine ET. However, further investigation was required to verify the optimal stent materials and antiproliferative drugs.

Topics: Animals; Chromium Alloys; Cobalt; Drug-Eluting Stents; Eustachian Tube; Hyperplasia; Sirolimus; Stents; Swine; Treatment Outcome

A novel drug eluting retrievable vena cava filter (RVCF) with a heparin-modified poly(ε-caprolactone) (hPCL) coating containing rapamycin was prepared by electrospraying. The in vitro drug release pattern showed that the encapsulated rapamycin in the coating can be sustainably released within one month, whereas activated partial thromboplastin time (APTT) and in vitro cell culture showed that the drug eluting RVCF can effectively extend blood clotting time and inhibit smooth muscle cell (SMC) and endothelial cell (EC) proliferation, respectively. The as-prepared drug eluting RVCF and corresponding commercial RVCF were implanted into the vena cava of sheep. The retrieval operation at a predetermined time point showed that the drug eluting RVCF had a much higher retrieval rate than the commercial RVCF. Comprehensive investigations, including histological, immunohistological and immunofluorescence analyses, on explanted veins were carried out. The results demonstrated that the as-prepared RVCF possessed excellent antihyperplasia properties in vivo, significantly improving the retrieval rate and extending the in vivo dwelling time in sheep. Consequently, the drug eluting RVCF has promising potential for application in the clinic to improve RVCF retrieval rates.

Topics: Animals; Device Removal; Heparin; Hyperplasia; Pulmonary Embolism; Retrospective Studies; Sheep; Sirolimus; Treatment Outcome; Vena Cava Filters

Neointimal hyperplasia is a persistent complication after vascular interventions, and it is also the leading cause of vascular graft restenosis and failure after arterial interventions, so novel treatment methods are needed to treat this complication. We hypothesized that adventitial injection of HA/SA hydrogel loaded with PLGA rapamycin nanoparticle (hydrogel-PLGA-rapamycin) could inhibit neointimal hyperplasia in a rat aortic wire injury model. The HA/SA hydrogel was fabricated by the interaction of hyaluronic acid (HA), sodium alginate (SA), and CaCO

Topics: Adventitia; Animals; Endothelial Cells; Hyaluronic Acid; Hydrogels; Hyperplasia; Nanoparticles; Neointima; Rats; Rats, Sprague-Dawley; Rhodamines; Sirolimus; Vascular System Injuries

Balloon angioplasty, stent implantation, and application of an arterial clamp during surgery can induce artery injury such as elastin breaks and endothelium injury, but there is little research focused on the injury induced by these therapeutic manipulations. We established a simple and reproducible small animal aortic injury model and examined intramural injection as a potential therapeutic method to alleviate injury.. The abdominal aorta of male Sprague Dawley (SD) rats or C57BL/6 J mice was clamped sequentially throughout its length. Transforming growth factor β1 (TGFβ1), SB431542, lipopolysaccharide (LPS), Necrostatin-1 (Nec-1), rapamycin, or MHY1485 contained in Pluronic gel was injected intramurally at day 0 or day 7. Animals were fed with chow containing 0.25% beta-aminopropionitrile (BAPN) to evaluate the influence of BAPN. All samples were harvested and examined by immunohistochemistry and immunofluorescence.. The clamped rat aorta showed luminal dilation, elastin fiber breaks, neointimal hyperplasia, and dissection (days 0-90). Intramural injection of TGFβ1, rapamycin and Nec-1 showed a protective effect on the injured aorta, whereas SB431542, MHY1485 and LPS showed more severe wall damage. The aortic lumen in rats fed with BAPN was significantly larger than in control rats (day 7). Mouse aorta showed similar injury with neointimal hyperplasia and elastin fiber breaks.. The rodent arterial injury model is reproducible and may mimic early changes of arterial injury. The model accommodates intramural injection of different drugs that may show mechanisms of arterial injury. Although this is a preliminary animal model, the intramural injection method may have potential clinical application in the future.

Topics: Aminopropionitrile; Animals; Aorta, Abdominal; Disease Models, Animal; Elastin; Hyperplasia; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Neointima; Poloxamer; Rats; Rats, Sprague-Dawley; Sirolimus

Loading and eluting drugs on self-expandable metallic stents (SEMSs) can be challenging in terms of fabrication, mechanical stability, and therapeutic effects. In this study, a flexible 3D nanonetworked silica film (NSF) capable of withstanding mechanical stress during dynamic expansion is constructed to function as a drug delivery platform on an entire SEMS surface. Despite covering a broad curved area, the synthesized NSF is defect-free and thin enough to increase the stent strut diameter (110 µm) by only 0.4 percent (110.45 µm). The hydrophobic modification of the surface enables loading of 4.7 times the sirolimus (SRL) concentration in NSF than Cypher, polymer-coated commercial stent, which is based on the same thickness of coating layer. Furthermore, SRL-loaded NSF exhibits a twofold delay in release compared to the control group without NSF. The SRL-loaded NSF SEMS significantly suppresses stent-induced tissue hyperplasia than the control SEMS in the rat esophagus (all variables, p < 0.05). Thus, the developed NSF is a promising polymer-free drug delivery platform to efficiently treat esophageal stricture.

Topics: Animals; Drug-Eluting Stents; Esophagus; Hyperplasia; Polymers; Rats; Silicon Dioxide; Sirolimus

Neointimal hyperplasia is a complex process after vascular interventions, acute platelet deposition and smooth muscle cell proliferation both contributed to this process. There are still no perfect solutions to solve this problem. Rivaroxaban is a novel anticoagulant that has been widely used in clinic, it has a good pharmacological effects both in vivo and in vitro. Chitosan microparticle rapamycin (MP-rapa) was fabricated, interspaces of polyglycolic acid (PGA) scaffold were used as a reservoir of MP-rapa, and the scaffold was coated with hyaluronic acid rivaroxaban (MP-rapa-riva). Scanning electronic microscopy (SEM) photographs were taken and water contact angles were measured, rat inferior vena cava (IVC) patch venoplasty model was used; patches were harvested at day 14 and examined by immunohistochemistry and immunofluorescence. SEM photographs showed the microparticles rapamycin were inside the interspace of the scaffold, hyaluronic acid rivaroxaban was also successfully coated onto the surface of the scaffold. There was a thinner neointima, fewer proliferating cell nuclear antigen (PCNA) positive cells, fewer macrophages in the MP-rapa and MP-rapa-riva grafts compared to the control PGA graft. The result showed that this scaffold with dual anticoagulation and antiproliferation functions can effectively inhibit venous neointimal hyperplasia, although this is an animal experiment, it showed promising potential clinical application in the future.

Topics: Animals; Chitosan; Hyaluronic Acid; Hyperplasia; Neointima; Rats; Rivaroxaban; Sirolimus; Tunica Intima

Following vein grafting, the vein must adapt to arterial hemodynamics, which can lead to intimal hyperplasia (IH) and restenosis. Moreover, endothelial-to-mesenchymal transition (EndMT) components are highly associated with IH. Therefore, in this study, we aimed to design an extravascular film loaded with rapamycin (extravascular rapamycin film [ERF]) to limit vein graft stenosis. The film exhibited stable physicochemical properties as well as in vivo and in vitro biocompatibility. In vivo, the film inhibited the EndMT by activating the autophagy pathway. Moreover, rapamycin enhanced this biological effect. Collectively, these findings highlighted the applicability of ERF as a new therapeutic target for preventing vein graft restenosis.

Topics: Autophagy; Constriction, Pathologic; Humans; Hyperplasia; Sirolimus

Intimal hyperplasia caused by vascular injury is an important pathological process of many vascular diseases, especially occlusive vascular disease. In recent years, Nano-drug delivery system has attracted a wide attention as a novel treatment strategy, but there are still some challenges such as high clearance rate and insufficient targeting.. In this study, we report a biomimetic ROS-responsive MM@PCM/RAP nanoparticle coated with macrophage membrane. The macrophage membrane with the innate "homing" capacity can superiorly regulate the recruitment of MM@PCM/RAP to inflammatory lesion to enhance target efficacy, and can also disguise MM@PCM/RAP nanoparticle as the autologous cell to avoid clearance by the immune system. In addition, MM@PCM/RAP can effectively improve the solubility of rapamycin and respond to the high concentration level of ROS accumulated in pathological lesion for controlling local cargo release, thereby increasing drug availability and reducing toxic side effects.. Our findings validate that the rational design, biomimetic nanoparticles MM@PCM/RAP, can effectively inhibit the pathological process of intimal injury with excellent biocompatibility.

Topics: Animals; Biomimetic Materials; Cell Membrane; Cell Proliferation; Cell Survival; Hyperplasia; Macrophages; Male; Mice; Mice, Inbred C57BL; Nanoparticle Drug Delivery System; Reactive Oxygen Species; Sirolimus; Tunica Intima; Zebrafish

In the last few years, the use of oral sirolimus has shown promising results in the treatment of some complex vascular anomalies, and recently, it has been used in patients with Sturge-Weber syndrome (SWS). We present the case of an 11-year-old girl with the diagnosis of SWS and hemifacial overgrowth treated with oral sirolimus. Throughout the eight months of follow-up, improvement of the port-wine birthmark, intraocular pressure, and neurocognitive development was noted. The mTOR inhibitors may be useful in the treatment of some patients with SWS.

Topics: Child; Face; Facial Asymmetry; Female; Humans; Hyperplasia; Port-Wine Stain; Sirolimus; Sturge-Weber Syndrome

The DESSOLVE III OCT substudy aimed to compare serially neointimal hyperplasia volume obstruction (%VO) between the thin-strut MiStent with early polymer elimination and nine-month sustained drug release from microcrystalline sirolimus and the durable polymer-coated everolimus-eluting XIENCE stent at six and 24 months after implantation.. The efficacy endpoint was %VO, calculated as abluminal neointimal volume/stent volume. Thirty-six patients (MiStent 16 patients, 16 lesions; XIENCE 20 patients, 22 lesions) underwent serial OCT evaluation at both six and 24 months. At six months, mean abluminal %VO was significantly lower in the MiStent group than in the XIENCE group (14.54±3.70% vs 19.11±6.70%; p=0.011), whereas the difference in %VO between the two groups decreased at 24 months (20.88±5.72% vs 23.50±7.33%; p=0.24). There was no significant difference in percentage malapposed struts and percentage uncovered struts between the two groups at both time points.. In the serial comparative OCT analysis of the MiStent versus the XIENCE, the MiStent showed a more favourable efficacy for preventing neointimal formation with comparable strut tissue coverage, as compared with the XIENCE at six months, but this difference in %VO decreased at 24 months so that the difference in neointima at 24 months was no longer significant.

Topics: Coronary Artery Disease; Drug-Eluting Stents; Everolimus; Humans; Hyperplasia; Neointima; Percutaneous Coronary Intervention; Polymers; Prosthesis Design; Sirolimus; Stents; Tomography, Optical Coherence; Treatment Outcome

For the surgical treatment of coronary artery disease, renal artery stenosis and other peripheral vascular diseases, there is significant demand for small diameter (inner diameter <6 mm) vascular grafts. However, autologous grafts are not always available when the substitute vascular grafts are severely diseased. In our previous work, hybrid small-diameter vascular grafts were successfully fabricated by combining electrospun polycaprolactone (PCL) and decellularized rat aorta (DRA). However, histological assessments of these grafts revealed the development of intimal hyperplasia, indicating potential negative impacts on the long-term patency of these grafts. To address this challenge, PCL nanofibers blended with rapamycin (RM) were electrospun outside the decellularized vascular graft to fabricate a RM-loaded hybrid tissue-engineered vascular graft (RM-HTEV), endowing the graft with a drug delivery function to prevent intimal hyperplasia. RM-HTEV possessed superior mechanical properties compared to DRA and exhibited a sustained drug release profile. To evaluate the applicability of RM-HTEV in vivo, abdominal aorta transplantation was performed on rats. Doppler sonography showed that the grafts were functional for up to 8 weeks in vivo. Moreover, histological analysis of explanted grafts 12 weeks postimplantation demonstrated that RM-HTEV significantly decreased neo-intimal hyperplasia compared with HTEV, without impairing reendothelialization and M2 macrophage polarization. Overall, RM-HTEV represents a promising strategy for developing small-diameter vascular grafts with great clinical translational potential. STATEMENT OF SIGNIFICANCE: In this study, a new type of rapamycin-loaded hybrid tissue-engineered vascular graft (RM-HTEV) was fabricated using electrospinning technology. The unique hybrid bi-layer structure endowed the RM-HTEV with multi-functionality: the exterior rapamycin-loaded electrospun PCL nanofibrous layer enhanced the mechanical properties of the graft and possessed drug releasing property; the interior decellularized aorta layer with porous structure could facilitate cell proliferation and migration. In in vivo implantation experiment, RM-HTEV exhibited satisfying long-term patency rate and significantly inhibited intimal hyperplasia without impairing re-endothelialization and M2 macrophage polarization. This strategy is expected to be a promising strategy for developing bioactive small-diameter vascular grafts with great clinical tran

Topics: Animals; Aorta, Abdominal; Bioprosthesis; Blood Vessel Prosthesis; Drug Delivery Systems; Hyperplasia; Male; Rats; Rats, Sprague-Dawley; Sirolimus; Tunica Intima; Vascular Grafting

Vein graft restenosis has an adverse impact on bridge vessel circulation and patient prognosis after coronary artery bypass grafting.. We used the extravascular supporter α-cyanoacrylate (α-CA), the local application rapamycin/sirolimus (RPM), and a combination of the two (α-CA-RPM) in rat models of autogenous vein graft to stimulate vein graft change. The aim of our study was to observe the effect of α-CA, RPM, and α-CA-RPM on vein hyperplasia.. Fifty healthy Sprague Dawley (SD) rats were randomized into the following 5 groups: sham, control, α-CA, RPM, and α-CA-RPM. Operating procedure as subsequently described was used to build models of grafted rat jugular vein on carotid artery on one side. The level of endothelin-1 (ET-1) was determined by enzyme-linked immunosorbent assay (ELISA). Grafted veins were observed via naked eye 4 weeks later; fresh veins were observed via microscope and image-processing software in hematoxylin-eosin (HE) staining and immunohistochemistry after having been fixed and stored" (i.e. First they were fixed and stored, and second they were observed); α-Smooth Muscle Actin (αSMA) and von Willebrand factor (vWF) were measured with reverse transcription-polymerase chain reaction (RT-PCR). Comparisons were made with single-factor analysis of variance and Fisher's least significant difference test, with p < 0.05 considered significant.. We found that intimal thickness of the α-CA, RPM, and α-CA-RPM groups was lower than that of the control group (p < 0.01), and the thickness of the α-CA-RPM group was notably lower than that of the α-CA and RPM groups (p < 0.05).. RPM combined with α-CA contributes to inhibiting intimal hyperplasia in rat models and is more effective for vascular patency than individual use of either α-CA or RPM.

Topics: Actins; Animals; Carotid Arteries; Cell Proliferation; Coronary Artery Bypass; Cyanoacrylates; Disease Models, Animal; Drug Combinations; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Graft Occlusion, Vascular; Hyperplasia; Jugular Veins; Male; Random Allocation; Rats, Sprague-Dawley; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima

Topics: Animals; Cyanoacrylates; Hyperplasia; Muscle, Smooth, Vascular; Rats; Sirolimus; Tunica Intima

PIK3CA-related overgrowth spectrum (PROS) are overgrowth diseases involving mesenchymal tissues caused by postzygotic variants in the PIK3CA gene. Fibro-Adipose hyperplasia or Overgrowth (FAO) belongs to PROS. We reported the beneficial effect of oral low-dose sirolimus therapy in a child affected by progressive FAO in term of stabilization of the disease, good tolerability, and easy management.

Topics: Absorptiometry, Photon; Adipose Tissue; Child, Preschool; Fetal Macrosomia; Genetic Predisposition to Disease; Humans; Hyperplasia; Magnetic Resonance Imaging; Mosaicism; Sirolimus; Treatment Outcome

The aim of this study was to compare neointima proliferation in three drug-eluting stents (DES) produced by the same company (Balton, Poland) which are covered with a biodegradable polymer and elute sirolimus (concentration: 1.0 and 1.2 µg/mm

Topics: Absorbable Implants; Aged; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Polymers; Predictive Value of Tests; Prosthesis Design; Risk Factors; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by aggressive and symmetric polyarthritis. Mammalian target of rapamycin (mTOR) was reported to be a new target for RA therapy and its inhibitor rapamycin can significantly reduce the invasive force of fibroblast-like synoviocytes. Here, we determined the effect of curcumin to alleviate inflammation and synovial hyperplasia for the therapy of RA.. Collagen-induced arthritis (CIA) was developed in Wistar rats and used as a model resembling RA in humans. Rats were treated with curcumin (200 mg/kg) and the mTOR inhibitor rapamycin (2.5 mg/kg) daily for 3 weeks. Effects of the treatment on local joint, peripheral blood, and synovial hyperplasia in the pathogenesis of CIA were analyzed.. Curcumin and rapamycin significantly inhibited the redness and swelling of ankles and joints in RA rats. Curcumin inhibited the CIA-induced mTOR pathway and the RA-induced infiltration of inflammatory cells into the synovium. Curcumin and rapamycin treatment inhibited the increased levels of proinflammatory cytokines including IL-1β, TNF-α, MMP-1, and MMP-3 in CIA rats.. Our findings show that curcumin alleviates CIA-induced inflammation, synovial hyperplasia, and the other main features involved in the pathogenesis of CIA via the mTOR pathway. These results provide evidence for the anti-arthritic properties of curcumin and corroborate its potential use for the treatment of RA.

Topics: Animals; Anti-Inflammatory Agents; Antirheumatic Agents; Arthritis, Experimental; Collagen Type II; Curcumin; Hyperplasia; Inflammation Mediators; Interleukin-1beta; Male; Matrix Metalloproteinase 1; Matrix Metalloproteinase 3; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Rats, Wistar; Signal Transduction; Sirolimus; Synovial Membrane; Synovitis; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha

We aimed to investigate the safety and efficacy of XINSORB bioresorbable sirolimus-eluting scaffold in porcine model. XINSORB scaffolds and metallic Firebird2™ stents were randomly implanted into minipigs' coronary arteries. Angiography, optical coherent tomography (OCT) and histopathological analyses were performed at post-procedure and 14-, 28-, 90-, 180-day follow-up. Thirty-two minipigs were enrolled. Eight XINSORB scaffolds and 8 Firebird2 stents were examined at each time point. Quantitative coronary angiography showed that in-scaffold late luminal loss (LLL) of XINSORB scaffold was 0.26 ± 0.13, 0.50 ± 0.16, 0.88 ± 0.29 and 0.43 ± 0.24 mm at 14-, 28, 90-, and 180-day follow-up respectively, and the corresponding diameter stenosis (DS) was 7.3 ± 4.7, 12.0 ± 9.5, 22.1 ± 8.0, and 16.0 ± 9.5%. Neither in-scaffold LLL nor DS of XINSORB scaffold was significantly different in comparison with Firebird2 stent. No difference of luminal area, device area, neointimal hyperplasia, and area stenosis was detected between two devices under OCT. Scaffold area of XINSORB remained steady through the observation. Histopathology revealed the similar findings. The greatest late recoil of XINSORB scaffold was about 4.12% at 90-day follow-up, which was comparable to Firebird2 stent. Both devices showed low injury or inflammation of vessel wall. XINSORB scaffold showed early neointimal coverage on struts within 28 days under scanning electron microscopy. XINSORB scaffold suppressed neointimal hyperplasia as effectively as Firebird2 did without obvious late device recoil during the 180 days follow-up. It is feasible to carry out clinical trial to investigate the safety and efficacy of XINSORB scaffold for patients with coronary artery diseases.

Topics: Animals; Cardiac Catheterization; Cardiovascular Agents; Coated Materials, Biocompatible; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Hyperplasia; Metals; Microscopy, Electron, Scanning; Models, Animal; Neointima; Percutaneous Coronary Intervention; Prosthesis Design; Prosthesis Failure; Sirolimus; Swine; Swine, Miniature; Time Factors; Tomography, Optical Coherence

Prosthetic grafts and patches are commonly used in cardiovascular surgery, however neointimal hyperplasia remains a significant concern, especially under low flow conditions. We hypothesized that delivery of rapamycin from nanoparticles (NP) covalently attached to patches allows sustained site-specific delivery of therapeutic agents targeted to inhibit localized neointimal hyperplasia. NP were covalently linked to pericardial patches using EDC/NHS chemistry and could deliver at least 360 ng rapamycin per patch without detectable rapamycin in serum; nanoparticles were detectable in the liver, kidney and spleen but no other sites within 24 hours. In a rat venous patch angioplasty model, control patches developed robust neointimal hyperplasia on the patch luminal surface characterized by Eph-B4-positive endothelium and underlying SMC and infiltrating cells such as macrophages and leukocytes. Patches delivering rapamycin developed less neointimal hyperplasia, less smooth muscle cell proliferation, and had fewer infiltrating cells but retained endothelialization. NP covalently linked to pericardial patches are a novel composite delivery system that allows sustained site-specific delivery of therapeutics; NP delivering rapamycin inhibit patch neointimal hyperplasia. NP linked to patches may represent a next generation of tissue engineered cardiovascular implants.

Topics: Angioplasty; Animals; Drug Carriers; Growth Inhibitors; Histocytochemistry; Hyperplasia; Nanoparticles; Neointima; Rats; Sirolimus; Transplants; Treatment Outcome

Constitutive activation of the mammalian target of rapamycin (mTOR) complexes mTORC1 and mTORC2 is associated with pulmonary hypertension (PH) and sustained growth of pulmonary artery (PA) smooth muscle cells (SMCs). We investigated whether selective mTORC1 activation in SMCs induced by deleting the negative mTORC1 regulator tuberous sclerosis complex 1 gene (TSC1) was sufficient to produce PH in mice. Mice expressing Cre recombinase under SM22 promoter control were crossed with TSC1(LoxP/LoxP) mice to generate SM22-TSC1(-/-) mice. At 8 weeks of age, SM22-TSC1(-/-) mice exhibited PH with marked increases in distal PA muscularization and Ki67-positive PASMC counts, without systemic hypertension or cardiac dysfunction. Marked activation of the mTORC1 substrates S6 kinase and 4E-BP and the mTORC2 substrates p-Akt(Ser473) and glycogen synthase kinase 3 was found in the lungs and pulmonary vessels of SM22-TSC1(-/-) mice when compared with control mice. Treatment with 5 mg/kg rapamycin for 3 weeks to inhibit mTORC1 and mTORC2 fully reversed PH in SM22-TSC1(-/-) mice. In chronically hypoxic mice and SM22-5HTT(+) mice exhibiting PH associated with mTORC1 and mTORC2 activation, PH was maximally attenuated by low-dose rapamycin associated with selective mTORC1 inhibition. Cultured PASMCs from SM22-TSC1(-/-), SM22-5HTT(+), and chronically hypoxic mice exhibited similar sustained growth-rate enhancement and constitutive mTORC1 and mTORC2 activation; both effects were abolished by rapamycin. Deletion of the downstream mTORC1 effectors S6 kinase 1/2 in mice also activated mTOR signaling and induced PH. We concluded that activation of mTORC1 signaling leads to increased PASMC proliferation and subsequent PH development.

Topics: Animals; Cell Proliferation; Cells, Cultured; Chronic Disease; Gene Deletion; Hyperplasia; Hypertension, Pulmonary; Hypoxia; Lung; Male; Metformin; Mice; Microfilament Proteins; Muscle Proteins; Muscle, Smooth; Myocytes, Smooth Muscle; Pulmonary Artery; Ribosomal Protein S6 Kinases, 90-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 1 Protein; Tumor Suppressor Proteins

Ovarian cancer is a disease of older women. However, the molecular mechanisms of ovarian aging and their contribution to the pathogenesis of ovarian cancer are currently unclear. mTOR signalling is a major regulator of aging as suppression of this pathway extends lifespan in model organisms. Overactive mTOR signalling is present in up to 80% of ovarian cancer samples and is associated with poor prognosis. This study examined the role of mTOR signalling in age-associated changes in ovarian surface epithelium (OSE). Histological examination of ovaries from both aged mice and women revealed OSE cell hyperplasia, papillary growth and inclusion cysts. These pathological lesions expressed bonafide markers of ovarian cancer precursor lesions, Pax8 and Stathmin 1, and were presented with elevated mTOR signalling. To understand whether overactive mTOR signalling is responsible for the development of these pathological changes, we analysed ovaries of the Pten trangenic mice and found significant reduction in OSE lesions compared to controls. Furthermore, pharmacological suppression of mTOR signalling significantly decreased OSE hyperplasia in aged mice. Treatment with mTOR inhibitors reduced human ovarian cancer cell viability, proliferation and colony forming ability. Collectively, we have established the role of mTOR signalling in age-related OSE pathologies and initiation of ovarian cancer.

Topics: Aging; Animals; Blotting, Western; Cell Line, Tumor; Cell Survival; Epithelial Cells; Epithelium; Female; Humans; Hyperplasia; Immunosuppressive Agents; Mice, Inbred C57BL; Mice, Transgenic; Ovary; PTEN Phosphohydrolase; Sirolimus; TOR Serine-Threonine Kinases

In-stent hyperplasia (ISH) may develop in regions of low endothelial shear stress (ESS), but the relationship between the magnitude of low ESS, the extent of ISH, and subsequent clinical events has not been investigated.. We assessed the association of poststent ESS with neointimal ISH and clinical outcomes in patients treated with percutaneous coronary interventions (PCI). Three-dimensional coronary reconstruction was performed in 374 post-PCI patients at baseline and 6 to 10 months follow-up as part of the PREDICTION Study. Each vessel was divided into 1.5-mm-long segments, and we calculated the local ESS within each stented segment at baseline. At follow-up, we assessed ISH and the occurrence of a clinically indicated repeat PCI for in-stent restenosis. In 246 total stents (54 overlapping), 100 (40.7%) were bare-metal stents (BMS), 104 (42.3%) sirolimus-eluting stents, and 42 (17.1%) paclitaxel-eluting stents. In BMS, low ESS post-PCI at baseline was independently associated with ISH (β=1.47 mm(2) per 1-Pa decrease; 95% CI, 0.38-2.56; P<0.01). ISH was minimal in drug-eluting stents. During follow-up, repeat PCI in BMS was performed in 21 stents (8.5%). There was no significant association between post-PCI ESS and in-stent restenosis requiring PCI.. Low ESS after BMS implantation is associated with subsequent ISH. ISH is strongly inhibited by drug-eluting stents. Post-PCI ESS is not associated with in-stent restenosis requiring repeat PCI. ESS is an important determinant of ISH in BMS, but ISH of large magnitude to require PCI for in-stent restenosis is likely attributed to factors other than ESS within the stent.

Topics: Aged; Coronary Restenosis; Drug-Eluting Stents; Early Diagnosis; Female; Follow-Up Studies; Hemodynamics; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Sirolimus; Stents; Stress, Mechanical; Treatment Outcome

Although previous optical coherence tomography (OCT) studies reported that restenosis tissue after implantation of a drug-eluting stent (DES) was composed of a variety of cells, the clinical significance of morphologic characteristics for in-stent neointimal tissue as assessed by OCT has not been clarified. We experienced a patient with stable angina who underwent percutaneous coronary intervention with a 2.5 × 18-mm DES implantation 6 months before the OCT examination. OCT imaging showed a mild intimal hyperplasia (39 % neointimal hyperplasia) with eccentric, heterogeneous tissue, predominantly of low signal intensity. Seventeen months after the initial procedure, OCT revealed a significant increase in percent neointimal hyperplasia of 58 %, with morphologically different intimal tissue of concentric homogeneous high intensity in the stented segments. This finding suggests that low-intensity intimal tissue morphology detected by OCT could be a morphometric predictor of late neointimal tissue growth after DES implantation.

Topics: Aged; Chest Pain; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Everolimus; Humans; Hyperplasia; Male; Neointima; Percutaneous Coronary Intervention; Sirolimus; Tomography, Optical Coherence

The study of kidney cancer pathogenesis and its treatment has been limited by the scarcity of genetically defined animal models. The FLCN gene that codes for the protein folliculin, mutated in Birt-Hogg-Dubé syndrome, presents a new target for mouse modeling of kidney cancer. Here we developed a kidney-specific knockout model by disrupting the mouse Flcn in the proximal tubules, thus avoiding homozygous embryonic lethality or neonatal mortality, and eliminating the requirement of loss of heterozygosity for tumorigenesis. This knockout develops renal cysts and early onset (6 months) of multiple histological subtypes of renal neoplasms featuring high tumor penetrance. Although the majority of the tumors were chromophobe renal cell carcinomas in affected mice under 1 year of age, papillary renal cell carcinomas predominated in the kidneys of older knockout mice. This renal neoplasia from cystic hyperplasia at 4 months to high-grade renal tumors by 16 months represented the progression of tumorigenesis. The mTOR and TGF-β signalings were upregulated in Flcn-deficient tumors, and these two activated pathways may synergetically cause renal tumorigenesis. Treatment of knockout mice with the mTOR inhibitor rapamycin for 10 months led to the suppression of tumor growth. Thus, our model recapitulates human Birt-Hogg-Dubé kidney tumorigenesis, provides a valuable tool for further study of Flcn-deficient renal tumorigenesis, and tests new drugs/approaches to their treatment.

Topics: Animals; Antibiotics, Antineoplastic; Carcinogenesis; Carcinoma, Renal Cell; Cysts; Disease Models, Animal; Hyperplasia; Kidney Neoplasms; Kidney Tubules, Proximal; Mice; Mice, Knockout; Proto-Oncogene Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transforming Growth Factor beta; Tumor Suppressor Proteins

In this study, we examined the impact of rapamycin on mTORC1 signaling during 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced keratinocyte proliferation and skin tumor promotion in both wild-type (FVB/N) and BK5.Akt(WT) mice. TPA activated mTORC1 signaling in a time-dependent manner in cultured primary mouse keratinocytes and a mouse keratinocyte cell line. Early activation (15-30 min) of mTORC1 signaling induced by TPA was mediated in part by PKC activation, whereas later activation (2-4 h) was mediated by activation of EGFR and Akt. BK5.Akt(WT) transgenic mice, where Akt1 is overexpressed in basal epidermis, are highly sensitive to TPA-induced epidermal proliferation and two-stage skin carcinogenesis. Targeting mTORC1 with rapamycin effectively inhibited TPA-induced epidermal hyperplasia and hyperproliferation as well as tumor promotion in a dose-dependent manner in both wild-type and BK5.Akt(WT) mice. A significant expansion (∼threefold) of the label retaining cell (LRC) population per hair follicle was observed in BK5.Akt(WT) mice compared to FVB/N mice. There was also a significant increase in K15 expressing cells in the hair follicle of transgenic mice that coincided with expression of phospho-Akt, phospho-S6K, and phospho-PRAS40, suggesting an important role of mTORC1 signaling in bulge-region keratinocyte stem cell (KSC) homeostasis. After 2 weeks of TPA treatment, LRCs had moved upward into the interfollicular epidermis from the bulge region of both wild-type and BK5.Akt(WT) mice. TPA-mediated LRC proliferation and migration was significantly inhibited by rapamycin. Collectively, the current data indicate that signaling through mTORC1 contributes significantly to the process of skin tumor promotion through effects on proliferation of the target cells for tumor development.

Topics: Animals; Antibiotics, Antineoplastic; Calcium-Calmodulin-Dependent Protein Kinases; Cell Line; Cell Movement; Cell Proliferation; Cell Transformation, Neoplastic; Chromones; ErbB Receptors; Female; Flavonoids; Hair Follicle; Hyperplasia; Keratinocytes; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred ICR; Mice, Transgenic; Morpholines; Multiprotein Complexes; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase C; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Skin Neoplasms; Tetradecanoylphorbol Acetate; TOR Serine-Threonine Kinases

We aimed to compare the vascular effects exclusive to antiproliferative agents by using identical stent and biodegradable polymeric matrices eluting everolimus (BP-EES) (Carlo; Balton) and paclitaxel (BP-PES) (Luc-Chopin2; Balton) in the porcine model of coronary injury. A total of 37 stents were implanted with 110% overstretch in the coronary arteries of 14 domestic pigs: 13 BP-PES, 16 BP-EES and eight bare metal stents (BMS) (Chopin2; Balton). Coronary angiography was performed after 28 and 90 days, the animals were sacrificed and the stented segments harvested for histopathological evaluation. At 28 days, BP-PES most effectively limited angiographic late loss (LL PES: 0.15±0.1 vs. EES: 0.40±0.3 vs. BMS: 0.5±0.2 mm; p=0.04) and neointimal thickness (NT) in histology (PES: 0.12 [0.1-0.2] vs. EES: 0.38 [0.3-0.4] vs. BMS: 0.35 [0.3-0.4] mm; p<0.01). The BP-PES had lower endothelialisation (EES: 100% vs. PES: 40±4% vs. BMS: 97.5±5%; p<0.01) and slightly higher inflammation scores (EES: 1 vs. PES: 2.1±0.3 vs. BMS: 1; p<0.01). At three months, LL remained unchanged in the EES and BMS groups in contrast to an increase in the PES group (EES: 0.38±0.3 vs. PES: 0.52±0.4 vs. BMS: 0.51±0.3 mm; p=0.69). NT stabilised at 90 days in the EES group in comparison to a fourfold increase in the PES group and a 30% increase in the BMS group (EES: 0.35 [0.3-0.5] vs. PES: 0.53 [0.5-0.8] vs. BMS: 0.46 [0.4-0.5] mm: p=0.07). Stent endothelialisation and inflammation were comparable at 90 days in all groups. Temporal differences in vascular response were seen by the delivery of different antiproliferative agents. In contrast to everolimus, paclitaxel seems to induce a slightly higher degree of inflammation in the short term, potentially leading to further neointimal hyperplasia in the long term.

Topics: Absorbable Implants; Animals; Coated Materials, Biocompatible; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Endothelium, Vascular; Everolimus; Hyperplasia; Inflammation; Models, Animal; Neointima; Paclitaxel; Polymers; Sirolimus; Stents; Swine

Open vascular reconstructions frequently fail due to the development of recurrent disease or intimal hyperplasia (IH). This paper reports a novel drug delivery method using a rapamycin-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs)/pluronic gel system that can be applied periadventitially around the carotid artery immediately following the open surgery. In vitro studies revealed that rapamycin dispersed in pluronic gel was rapidly released over 3 days whereas release of rapamycin from rapamycin-loaded PLGA NPs embedded in pluronic gel was more gradual over 4 weeks. In cultured rat vascular smooth muscle cells (SMCs), rapamycin-loaded NPs produced durable (14 days versus 3 days for free rapamycin) inhibition of phosphorylation of S6 kinase (S6K1), a downstream target in the mTOR pathway. In a rat balloon injury model, periadventitial delivery of rapamycin-loaded NPs produced inhibition of phospho-S6K1 14 days after balloon injury. Immunostaining revealed that rapamycin-loaded NPs reduced SMC proliferation at both 14 and 28 days whereas rapamycin alone suppressed proliferation at day 14 only. Moreover, rapamycin-loaded NPs sustainably suppressed IH for at least 28 days following treatment, whereas rapamycin alone produced suppression on day 14 with rebound of IH by day 28. Since rapamycin, PLGA, and pluronic gel have all been approved by the FDA for other human therapies, this drug delivery method could potentially be translated into human use quickly to prevent failure of open vascular reconstructions.

Topics: Adventitia; Animals; Carotid Arteries; Cell Proliferation; Cell Survival; Drug Delivery Systems; Hyperplasia; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nanoparticles; Phosphorylation; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases; Sirolimus

Intimal hyperplasia produces restenosis (re-narrowing) of the vessel lumen following vascular intervention. Drugs that inhibit intimal hyperplasia have been developed, however there is currently no clinical method of perivascular drug-delivery to prevent restenosis following open surgical procedures. Here we report a poly(ε-caprolactone) (PCL) sheath that is highly effective in preventing intimal hyperplasia through perivascular delivery of rapamycin. We first screened a series of bioresorbable polymers, i.e., poly(lactide-co-glycolide) (PLGA), poly(lactic acid) (PLLA), PCL, and their blends, to identify desired release kinetics and sheath physical properties. Both PLGA and PLLA sheaths produced minimal (<30%) rapamycin release within 50days in PBS buffer. In contrast, PCL sheaths exhibited more rapid and near-linear release kinetics, as well as durable integrity (>90days) as evidenced in both scanning electron microscopy and subcutaneous embedding experiments. Moreover, a PCL sheath deployed around balloon-injured rat carotid arteries was associated with a minimum rate of thrombosis compared to PLGA and PLLA. Morphometric analysis and immunohistochemistry revealed that rapamycin-loaded perivascular PCL sheaths produced pronounced (85%) inhibition of intimal hyperplasia (0.15±0.05 vs 1.01±0.16), without impairment of the luminal endothelium, the vessel's anti-thrombotic layer. Our data collectively show that a rapamycin-loaded PCL delivery system produces substantial mitigation of neointima, likely due to its favorable physical properties leading to a stable yet flexible perivascular sheath and steady and prolonged release kinetics. Thus, a PCL sheath may provide useful scaffolding for devising effective perivascular drug delivery particularly suited for preventing restenosis following open vascular surgery.

Topics: Animals; Cardiovascular Agents; Carotid Artery Injuries; Carotid Stenosis; Cell Proliferation; Chemistry, Pharmaceutical; Delayed-Action Preparations; Disease Models, Animal; Drug Carriers; Hyperplasia; Kinetics; Linear Models; Male; Neointima; Polyesters; Rats; Rats, Sprague-Dawley; Sirolimus; Solubility; Technology, Pharmaceutical

The mTOR pathway has recently been suggested as a new potential target for therapy in adrenocortical carcinomas (ACCs). The aim of the current study is to describe the expression of the mTOR pathway in normal adrenals (NAs) and pathological adrenals and to explore whether there are correlation between the expression of these proteins and the in vitro response to sirolimus. For this purpose, the MTOR, S6K1 (RPS6KB1), and 4EBP1 (EIF4EBP1) mRNA expression were evaluated in ten NAs, ten adrenal hyperplasias (AHs), 17 adrenocortical adenomas (ACAs), and 17 ACCs by qPCR, whereas total(t)/phospho(p)-MTOR, t/p-S6K, and t/p-4EBP1 protein expression were assessed in three NAs, three AHs, six ACAs, and 20 ACCs by immunohistochemistry. The effects of sirolimus on cell survival and/or cortisol secretion in 12 human primary cultures of adrenocortical tumors (ATs) were also evaluated. In NAs and AHs, layer-specific expression of evaluated proteins was observed. S6K1 mRNA levels were lower in ACCs compared with NAs, AHs, and ACAs (P<0.01). A subset of ATs presented a moderate to high staining of the evaluated proteins. Median t-S6K1 protein expression in ACCs was lower than that in ACAs (P<0.01). Moderate to high staining of p-S6K1 and/or p-4EBP1 was observed in most ATs. A subset of ACCs not having moderate to high staining had a higher Weiss score than others (P<0.029). In primary AT cultures, sirolimus significantly reduced cell survival or cortisol secretion only in sporadic cases. In conclusion, these data suggest the presence of an activated mTOR pathway in a subset of ATs and a possible response to sirolimus only in certain ACC cases.

Topics: Adaptor Proteins, Signal Transducing; Adrenal Cortex; Adrenal Cortex Neoplasms; Adrenocortical Adenoma; Adrenocortical Carcinoma; Adult; Antibiotics, Antineoplastic; Cell Cycle Proteins; Cell Line, Tumor; Child; Child, Preschool; Humans; Hyperplasia; Phosphoproteins; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Messenger; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Uterine leiomyomata are the most common tumors found in the female reproductive tract. Despite the high prevalence and associated morbidities of these benign tumors, little is known about the molecular basis of uterine leiomyoma development and progression. Loss of the Tuberous Sclerosis 2 (TSC2) tumor suppressor has been proposed as a mechanism important for the etiology of uterine leiomyomata based on the Eker rat model. However, conflicting evidence showing increased TSC2 expression has been reported in human uterine leiomyomata, suggesting that TSC2 might not be involved in the pathogenesis of this disorder. We have produced mice with conditional deletion of the Tsc2 gene in the myometria to determine whether loss of TSC2 leads to leiomyoma development in murine uteri. Myometrial hyperplasia and increased collagen deposition was observed in Tsc2(cKO) mice compared with control mice, but no leiomyomata were detected by post-natal week 24. Increased signaling activity of mammalian target of rapamycin complex 1, which is normally repressed by TSC2, was also detected in the myometria of Tsc2(cKO) mice. Treatment of the mutant mice with rapamycin significantly inhibited myometrial expansion, but treatment with the progesterone receptor modulator, mifepristone, did not. The ovaries of the Tsc2(cKO) mice appeared normal, but half the mice were infertile and most of the other half became infertile after a single litter, which was likely due to oviductal blockage. Our study shows that although TSC2 loss alone does not lead to leiomyoma development, it does lead to myometrial hyperplasia and fibrosis.

Topics: Animals; Female; Fertility; Fibrosis; Gene Deletion; Hyperplasia; Leiomyoma; Mechanistic Target of Rapamycin Complex 1; Mesoderm; Mice; Mullerian Ducts; Multiprotein Complexes; Myometrium; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

The serial changes in neointimal tissues were compared between everolimus-eluting stent (EES) and bare-metal stent (BMS) in the porcine coronary artery using optical coherence tomography (OCT).. Serial (1, 3, and 6 month follow-up after stent implantation) OCT examinations were performed in 15 swine with 15 BMS- and 15 EES-treated lesions in porcine coronary arteries.. In BMS-implanted lesions, neointimal volume decreased from 7.3 mm(3) to 6.9 mm(3) and 6.4 mm(3) at 1, 3, and 6 months follow-up without statistical significance (P = 0.369). At the time points of 1, 3, and 6 months, neointimal tissue appearance was mainly a homogeneous pattern (80.0%, 93.3%, and 100%, resp.), while the other pattern was layered. In contrast, in EES-implanted lesions, neointimal volume significantly increased from 4.8 mm(3) to 9.8 mm(3) between 1 and 3 months but significantly decreased to 8.6 mm(3) between 3 and 6 months (P < 0.001). Between 1 and 3 months, the layered pattern of neointimal tissue increased from 26.7% to 66.7% but decreased to 20.0% between 3 and 6 months.. EES had a biphasic pattern of neointimal amounts that correlated with changes in neointimal morphology.

Topics: Animals; Blood Vessel Prosthesis; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Everolimus; Hyperplasia; Neointima; Sirolimus; Sus scrofa; Tomography, Optical Coherence

Previous intravascular ultrasound studies have shown that echolucent neointimal hyperplasia occasionally appears after bare-metal stent (BMS) or sirolimus-eluting stent (SES) implantation. Optical coherence tomography (OCT) studies have also demonstrated that paclitaxel-eluting stent (PES) restenosis exhibited similar images showing low signal intensity areas (LSIA) surrounding stent struts and three-layer appearance (TLA). The aim of the present study was to investigate the clinical significance of LSIA on OCT images in various types of stents. Fifty nine consecutive patients who underwent scheduled follow-up coronary angiography and OCT were enrolled. There was no significant difference in the prevalence of LSIA among the 3 stent groups (BMS 30%, SES 19%, PES 28%, P = 0.70). LSIA thickness was larger in the PES group than in the other stent groups (BMS 0.51 ± 0.21 mm, SES 0.35 ± 0.06 mm, PES 0.87 ± 0.19 mm, P < 0.01). The ratio of LSIA thickness to the neointimal thickness was also larger in PES compared with other stents (BMS 53 ± 9 %, SES 57 ± 8 %, PES 77 ± 5 %, P < 0.01). Also, LSIA thickness in patients with in-stent restenosis (ISR) was significantly larger than in those without ISR (0.37 ± 0.37 mm versus 0.12 ± 0.26 mm, P = 0.048). Our results suggest that LSIA might be involved in excessive neointimal formation, and that the healing response after PES implantation might be different from BMS or SES.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Disease; Coronary Restenosis; Female; Humans; Hyperplasia; Immunosuppressive Agents; Japan; Male; Middle Aged; Neointima; Outcome Assessment, Health Care; Paclitaxel; Postoperative Complications; Prospective Studies; Sirolimus; Stents; Tomography, Optical Coherence; Tubulin Modulators

Two patients who underwent simultaneous kissing stenting with sirolimus-eluting stents in the left main coronary artery were investigated with optical coherence tomography (OCT) at just more than 1 year postoperatively. In both cases, follow-up angiogram indicated complete coverage of the new metal carina with a membranous diaphragm, yet OCT showed varying tissue-coverage patterns transitioning from stent inflow to stent outflow. These patterns included single-strut coverage, bridge-like membrane formation between more than 1 strut, and end-to-end coverage of the carina; no uncovered stent struts were detected. OCT also demonstrated mixed patterns of tissue characteristics on the metal carina, ranging from poor endothelialization to modest neointima formation. These varying tissue characteristics suggest that the process of tissue coverage in the metal carina is different from that occurring on the vessel wall; this may indicate delayed healing in the carina.

Topics: Aged; Aged, 80 and over; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Endothelium, Vascular; Female; Humans; Hyperplasia; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

PTEN is one of the most frequently mutated tumor suppressor genes in human cancers. The role of PTEN in carcinogenesis has been validated by knockout mouse models. PTEN heterozygous mice develop neoplasms in multiple organs. Unfortunately, the embryonic lethality of biallelic excision of PTEN has inhibited the study of complete PTEN deletion in the development and progression of cancer. By crossing PTEN conditional knockout mice with transgenic mice expressing a tamoxifen-inducible Cre-ER(T) under the control of a chicken actin promoter, we have generated a tamoxifen-inducible mouse model that allows temporal control of PTEN deletion. Interestingly, administration of a single dose of tamoxifen resulted in PTEN deletion mainly in epithelial cells, but not in stromal, mesenchymal or hematopoietic cells. Using the mT/mG double-fluorescent Cre reporter mice, we demonstrate that epithelial-specific PTEN excision was caused by differential Cre activity among tissues and cells types. Tamoxifen-induced deletion of PTEN resulted in extremely rapid and consistent formation of endometrial in situ adenocarcinoma, prostate intraepithelial neoplasia and thyroid hyperplasia. We also analyzed the role of PTEN ablation in other epithelial cells, such as the tubular cells of the kidney, hepatocytes, colonic epithelial cells or bronchiolar epithelium, but those tissues did not exhibit neoplastic growth. Finally, to validate this model as a tool to assay the efficacy of anti-tumor drugs in PTEN deficiency, we administered the mTOR inhibitor everolimus to mice with induced PTEN deletion. Everolimus dramatically reduced the progression of endometrial proliferations and significantly reduced thyroid hyperplasia. This model could be a valuable tool to study the cell-autonomous mechanisms involved in PTEN-loss-induced carcinogenesis and provides a good platform to study the effect of anti-neoplastic drugs on PTEN-negative tumors.

Topics: Adenocarcinoma; Alleles; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Endometrial Neoplasms; Endometrium; Epithelial Cells; Everolimus; Female; Gene Deletion; Humans; Hyperplasia; Integrases; Male; Mice; Mice, Knockout; Precancerous Conditions; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; PTEN Phosphohydrolase; Recombination, Genetic; Sirolimus; Stromal Cells; Tamoxifen; Thyroid Gland; Thyroid Neoplasms

Restenosis after angioplasty remains a serious complication in clinical cardiology. This study aims to investigate the stealth colloidal systems for local intra-arterial drug delivery. Micelles from polyethylene glycol conjugated with phosphatidylethanolamine and PEGylated liposomes loaded with sirolimus were prepared and characterized with regard to their loading efficiency, particle size distribution, zeta potential, morphology, nuclear magnetic resonance spectroscopy, drug release profile and stability. The antirestenotic effects of the sirolimus-loaded micelles (14 nm) and liposomes (90 nm) were evaluated and compared in the rat carotid injury model following local intravascular delivery. In comparison to control groups, treatment of balloon injured rats with drug loaded micelles and nanoliposomes significantly reduced vascular stenosis by 42% and 19%, respectively (P<0.05). In addition, the luminal area was significantly enlarged by 39% and 60% following treatment with sirolimus-loaded liposomes and micelles, respectively (P<0.05). Immunohistochemistry revealed that sirolimus-loaded nanocarriers suppressed cell proliferation (Ki67-positive cells) as compared to control groups without affecting the density of smooth muscle actin staining. These results suggest that both colloidal nanocarriers could serve as effective intramural drug delivery systems for the treatment of restenosis; however, phospholipid based micelles provided better antirestenotic effects than PEGylated liposomes.

Topics: Angioplasty, Balloon, Coronary; Animals; Carotid Artery Injuries; Hyperplasia; Lipids; Liposomes; Male; Micelles; Neointima; Polyethylene Glycols; Rats; Rats, Sprague-Dawley; Sirolimus

Endometrial cancer is the most commonly diagnosed gynecologic malignancy worldwide; yet the tumor microenvironment, especially the fibroblast cells surrounding the cancer cells, is poorly understood. We established four primary cultures of fibroblasts from human endometrial cancer tissues (cancer-associated fibroblasts, CAFs) using antibody-conjugated magnetic bead isolation. These relatively homogenous fibroblast cultures expressed fibroblast markers (CD90, vimentin and alpha-smooth muscle actin) and hormonal (estrogen and progesterone) receptors. Conditioned media collected from CAFs induced a dose-dependent proliferation of both primary cultures and cell lines of endometrial cancer in vitro (175%) when compared to non-treated cells, in contrast to those from normal endometrial fibroblast cell line (51%) (P<0.0001). These effects were not observed in fibroblast culture derived from benign endometrial hyperplasia tissues, indicating the specificity of CAFs in affecting endometrial cancer cell proliferation. To determine the mechanism underlying the differential fibroblast effects, we compared the activation of PI3K/Akt and MAPK/Erk pathways in endometrial cancer cells following treatment with normal fibroblasts- and CAFs-conditioned media. Western blot analysis showed that the expression of both phosphorylated forms of Akt and Erk were significantly down-regulated in normal fibroblasts-treated cells, but were up-regulated/maintained in CAFs-treated cells. Treatment with specific inhibitors LY294002 and U0126 reversed the CAFs-mediated cell proliferation (P<0.0001), suggesting for a role of these pathways in modulating endometrial cancer cell proliferation. Rapamycin, which targets a downstream molecule in PI3K pathway (mTOR), also suppressed CAFs-induced cell proliferation by inducing apoptosis. Cytokine profiling analysis revealed that CAFs secrete higher levels of macrophage chemoattractant protein (MCP)-1, interleukin (IL)-6, IL-8, RANTES and vascular endothelial growth factor (VEGF) than normal fibroblasts. Our data suggests that in contrast to normal fibroblasts, CAFs may exhibit a pro-tumorigenic effect in the progression of endometrial cancer, and PI3K/Akt and MAPK/Erk signaling may represent critical regulators in how endometrial cancer cells respond to their microenvironment.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Cell Adhesion Molecules; Cell Proliferation; Cell Separation; Cytokines; Endometrial Neoplasms; Endometrium; Enzyme Activation; Epithelial Cell Adhesion Molecule; Epithelial Cells; Female; Fibroblasts; Humans; Hyperplasia; MAP Kinase Signaling System; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Sirolimus; Thy-1 Antigens; Tumor Cells, Cultured

Sirolimus (rapamycin) is used in drug-eluting stent strategies and proved clearly superior in this application compared with other immunomodulators such as pimecrolimus. The molecular basis of this action of sirolimus in the vascular system is still incompletely understood. Measurements of cell proliferation in human coronary artery smooth muscle cells (hCASM) demonstrated a higher antiproliferative activity of sirolimus compared with pimecrolimus. Although sirolimus lacks inhibitory effects on calcineurin, nuclear factor of activated T-cell activation in hCASM was suppressed to a similar extent by both drugs at 10 μM. Sirolimus, but not pimecrolimus, inhibited agonist-induced and store-operated Ca(2+) entry as well as cAMP response element binding protein (CREB) phosphorylation in human arterial smooth muscle, suggesting the existence of an as-yet unrecognized inhibitory effect of sirolimus on Ca(2+) signaling and Ca(2+)-dependent gene transcription. Electrophysiological experiments revealed that only sirolimus but not pimecrolimus significantly blocked the classical stromal interaction molecule/Orai-mediated, store-operated Ca(2+) current reconstituted in human embryonic kidney cells (HEK293). A link between Orai function and proliferation was confirmed by dominant-negative knockout of Orai in hCASM. Analysis of the effects of sirolimus on cell proliferation and CREB activation in an in vitro model of arterial intervention using human aorta corroborated the ability of sirolimus to suppress stent implantation-induced CREB activation in human arteries. We suggest inhibition of store-operated Ca(2+) entry based on Orai channels and the resulting suppression of Ca(2+) transcription coupling as a key mechanism underlying the antiproliferative activity of sirolimus in human arteries. This mechanism of action is specific for sirolimus and not a general feature of drugs interacting with FK506-binding proteins.

Topics: Aorta; Calcium Channels; Calcium Signaling; Cardiovascular Agents; Cell Proliferation; Coronary Vessels; Cyclic AMP Response Element-Binding Protein; Dose-Response Relationship, Drug; Gene Knockout Techniques; HEK293 Cells; Humans; Hyperplasia; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NFATC Transcription Factors; ORAI1 Protein; Phosphorylation; Sirolimus; Stents; Tacrolimus; Time Factors; Tissue Culture Techniques; Transcription, Genetic; Transfection

This study sought to assess stent-vessel interactions after drug-eluting stent (DES) implantation in unprotected left main coronary artery (ULM) by frequency-domain optical coherence tomography (FD-OCT).. Percutaneous coronary intervention using DES in ULM has been increasingly performed in routine practice. Recently, FD-OCT assessments of DES-vessel interactions have been used as surrogates for DES safety; however, there are no FD-OCT studies in ULM.. We prospectively enrolled 33 consecutive patients with ULM disease treated with sirolimus- (n = 11) and everolimus-eluting stents (n = 22). FD-OCT assessments were performed post-percutaneous coronary intervention and at 9-month follow-up. Three different segments of ULM were compared: distal (DIS), bifurcation (BIF), and ostial-body (BODY). The primary endpoints were percentages of uncovered and malapposed struts at 9-month follow-up, and the secondary endpoint was neointimal hyperplasia area.. We analyzed 25,873 stent struts. Significant differences were demonstrated for percentage of uncovered struts (3.4%, 11.7%, and 18.7%, respectively for DIS, BIF, and BODY; p < 0.05 for all the comparisons). Malapposition was also more common in BODY (5.3%) than in DIS (0.6%) and BIF (2.0%) segments (p < 0.05 for BODY vs. DIS, and BODY vs. BIF). Equivalent neointimal hyperplasia areas were demonstrated in all segments. Acute malapposition rates led to different patterns of DES-vessel interactions at 9-month follow-up.. Distinct patterns of DES-vessel interactions were demonstrated in different segments of ULM. Acute stent strut malapposition affects these findings.

Topics: Aged; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Chronic renal failure (CRF) is associated with increased cardiovascular mortality, and medial vascular smooth muscle cell (VSMC) hypertrophy, proliferation, and calcification play a pivotal role in uremic vasculopathy. Glucose transporter-1 (GLUT1) facilitates the transport of glucose into VSMCs, and GLUT1 overexpression associated with high glucose influx leads to a stimulation of VSMC proliferation. However, the role of GLUT1 in uremic vasculopathy remains unclear. This study aimed to identify changes in the expression of GLUT1 in VSMCs in the setting of experimental uremia and investigate whether Akt/tuberous sclerosis complex subunit 2 (TSC2)/mammalian target of rapamycin (mTOR)/ribosomal S6 protein kinase (S6K) signaling, which plays a crucial role in VSMC proliferation and glucose metabolism, is involved in the regulation of GLUT1 expression.. In vivo experimental CRF was induced in Wistar rats by 5/6 nephrectomy, and the GLUT1 expression in aortic tissue was determined by the reverse transcriptase-polymerase chain reaction, immunoblotting, and immunohistochemical staining. Indoxyl sulfate (IS) is a uremic retention solute proven with pro-proliferative effect on rat VSMCs, and we further studied the expression of GLUT1 in rat A7r5 rat embryonic aortic cells stimulated by IS in the presence or absence of phloretin, a GLUT1 inhibitor, to explore the pathogenic role of GLUT1 in uremic vasculopathy. The contribution of Akt/TSC2/mTOR/S6K signaling in modifying the GLUT1 expression was also assessed.. Eight weeks after 5/6 nephrectomy, aortic tissue obtained from CRF rats exhibited increased wall thickness and VSMC hypertrophy, hyperplasia, and degeneration. Compared with the sham-operated control group, the messenger (m)RNA and protein abundance of GLUT1 were both markedly increased in CRF rats. In vitro, IS induced a significant increase in expression of GLUT1 protein as well as pro-proliferative cyclin D1 and p21 mRNA and a modest increase in expression of antiapoptotic p53 mRNA in A7r5 cells, whereas inhibition of GLUT1 mediated glucose influx reduced the pro-proliferative and antiapoptotic effects of IS. In addition to increased GLUT1 expression, IS significantly suppressed Akt and TSC2 phosphorylation after 6-hour and 12-hour treatment, but increased S6K phosphorylation after 3-hour treatment. Inactivation of mTOR downstream signaling by rapamycin treatment inhibited S6K phosphorylation and abolished the stimulatory effect of IS on GLUT1 expression.. In vivo and in vitro experimental CRF displayed prominent GLUT1 upregulation in VSMCs. The uremic toxin IS stimulated proliferation of VSMCs possibly through induction of GLUT1 expression. The Akt/TSC/mTOR/S6K signaling pathway may be one of the mechanisms underlying the upregulation of GLUT1 expression in uremic VSMCs.

Topics: Animals; Aorta; Apoptosis; Blotting, Western; Cell Line; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; Disease Models, Animal; Glucose; Glucose Transporter Type 1; Hyperplasia; Hypertrophy; Immunohistochemistry; Indican; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nephrectomy; Phloretin; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Renal Insufficiency; Reverse Transcriptase Polymerase Chain Reaction; Ribosomal Protein S6 Kinases; RNA, Messenger; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Protein p53; Tumor Suppressor Proteins; Up-Regulation; Uremia

Topics: Adipose Tissue; Adult; Biopsy; Humans; Hyperplasia; Immunosuppressive Agents; Kidney; Kidney Diseases; Kidney Transplantation; Lipomatosis; Male; Sirolimus; Time Factors; Tomography, X-Ray Computed

To report the four-month and nine-month angiographic results as well as one-year clinical follow-up from the first-in-man study with the silicon carbide and sirolimus-eluting bioabsorbable polymer (poly-L-lactic acid (PLLA) polymer) -coated cobalt-chromium Orsiro stent.. A group of 30 patients with documented myocardial ischaemia related to a single de novo coronary stenosis up to 22 mm in length, in vessels with a 2.5 to 3.5 mm reference diameter, and between >50% and <90% diameter stenosis were enrolled at two sites. The primary endpoint of the study was in-stent late lumen loss at nine months. The secondary endpoints included major adverse cardiac events (MACE) at one year defined as the composite of cardiac death, ischaemia-driven target lesion revascularisation (TLR) and target vessel myocardial infarction (MI). Procedural success was 100%. Angiographic late lumen loss was 0.12±0.19 mm and 0.05±0.22 mm at four and nine months respectively. At one-year clinical follow-up, the composite MACE was 10% with one patient who died from cardiac death and two patients who had ischaemia-driven target lesion revascularisation. There was no report of MI or stent thrombosis.. The Orsiro drug-eluting stent demonstrated potency with low rates of in-stent neointimal hyperplasia and cardiovascular events but warrants further evaluation in a larger population cohort with longer follow-up time points.

Topics: Aged; Carbon Compounds, Inorganic; Chromium Alloys; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Incidence; Male; Middle Aged; Myocardial Infarction; Neointima; Percutaneous Coronary Intervention; Prospective Studies; Silicon Compounds; Sirolimus; Treatment Outcome

Recent studies reported favorable angiographic and clinical outcomes after everolimus-eluting stent (EES) implantation. However, there were no studies to assess vascular responses after EES implantation using optical coherence tomography (OCT). Therefore, the OCT findings in EES were investigated and compared with those in sirolimus-eluting stent (SES). Follow-up OCT studies were performed in 110 lesions (40 EES and 70 SES) of 104 patients at 9 months after stent implantation. The strut apposition, neointimal hyperplasia (NIH) thickness and stent coverage on each stent struts were evaluated. The mean NIH thickness was significantly greater in EES-treated lesions than in SES-treated lesions (115 ± 52 μm vs. 89 ± 58 μm, P = 0.001, respectively). The percentage of uncovered strut was significantly smaller in EES-treated lesions than in SES-treated lesions (4.4 ± 4.7% vs. 10.5 ± 12.7%, P = 0.016, respectively). There was no significant difference in the percentage of malapposed strut between the two groups (0.4 ± 0.8% in EES vs. 1.7 ± 4.5% in SES, P = 0.344). The incidence of intracoronary thrombus was significantly lower in EES-treated lesions than in SES-treated lesions (5.0% vs. 34.3%, P < 0.001, respectively). EES showed a significantly lower incidence of uncovered stent struts and intracoronary thrombus than SES in 9-month follow-up OCT examination. Compared to SES, EES might have more favorable vascular responses after stent implantation.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Male; Middle Aged; Neointima; Predictive Value of Tests; Registries; Republic of Korea; Retrospective Studies; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

To quantify with in vivo OCT and histology, the device/vessel interaction after implantation of the bioresorbable vascular scaffold (BVS). We evaluated the area and thickness of the strut voids previously occupied by the polymeric struts, and the neointimal hyperplasia (NIH) area covering the endoluminal surface of the strut voids (NIH(EV)), as well as the NIH area occupying the space between the strut voids (NIH(BV)), in healthy porcine coronary arteries at 2, 3 and 4 years after implantation of the device. Twenty-two polymeric BVS were implanted in the coronary arteries of 11 healthy Yucatan minipigs that underwent OCT at 2, 3 and 4 years after implantation, immediately followed by euthanasia. The areas and thicknesses of 60 corresponding strut voids previously occupied by the polymeric struts and the size of 60 corresponding NIH(EV) and 49 NIH(BV) were evaluated with both OCT and histology by 2 independent observers, using a single quantitative analysis software for both techniques. At 3 and 4 years after implantation, the strut voids were no longer detectable by OCT or histology due to complete polymer resorption. However, analysis performed at 2 years still provided clear delineation of these structures, by both techniques. The median [ranges] areas of these strut voids were 0.04 [0.03-0.16] and 0.02 [0.01-0.07] mm(2) by histology and OCT, respectively. The mean (±SD) thickness by histology and OCT was 220 ± 40 and 120 ± 20 μm, respectively. The median [ranges] NIH(EV) by histology and OCT was 0.07 [0.04-0.20] and 0.03 [0.01-0.08] mm(2), while the mean (±SD) NIH(BV) by histology and OCT was 0.13 ± 0.07 and 0.10 ± 0.06 mm(2). Our study indicates that in vivo OCT of the BVS provides correlated measurements of the same order of magnitude as histomorphometry, and is reproducible for the evaluation of certain vascular and device-related characteristics. However, histology systematically gives larger values for all the measured structures compared to OCT, at 2 years post implantation.

Topics: Absorbable Implants; Angioplasty, Balloon, Coronary; Animals; Cardiovascular Agents; Coronary Vessels; Everolimus; Feasibility Studies; Hyperplasia; Models, Animal; Neointima; Pilot Projects; Sirolimus; Swine; Swine, Miniature; Time Factors; Tissue Scaffolds; Tomography, Optical Coherence

Previous optical coherence tomography (OCT) studies in patients with drug-eluting stents (DESs)-related very late stent thrombosis (VLST) were scarce. Therefore, we investigated OCT findings of VLST after implantation of DESs. Using OCT, we analyzed the status of stent struts and neointimal characteristics in 18 patients who developed VLST after DES implantation. These results were compared to those in 57 patients with neointimal hyperplasia causing >40% diameter stenosis. Lipid-laden neointima was defined as a region with marked signal attenuation and a diffuse border. Four (22.2%) of 18 patients with VLST had ruptured and lipid-laden neointima inside DESs without uncovered or malapposed stent struts. In the remaining 14 patients who developed VLST without neointimal rupture, uncovered and malapposed struts were observed in nine and seven patients, respectively, and lipid-laden neointima in four patients. Lipid-laden neointima was more frequently observed in four patients with neointimal rupture than in 14 patients without neointimal rupture (100% vs. 28.6%, respectively, P = 0.023). Of 57 patients with neointimal hyperplasia, eight (14.0%) had lipid-laden neointima. Time to OCT study after DES implantation was significantly longer in the eight patients with lipid-laden neointima than in 49 patients without lipid-laden neointima (45.5 ± 17.7 months vs. 11.7 ± 7.2 months, respectively, P < 0.001). Lipid-laden neointima was detected in some patients with neointimal hyperplasia > 1 year after DES implantation. In addition to uncovered or malapposed struts, rupture of lipid-laden neointima inside DESs was identified in some patients with DES-related VLST.

Topics: Adult; Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Lipid Metabolism; Male; Middle Aged; Neointima; Paclitaxel; Predictive Value of Tests; Prosthesis Design; Republic of Korea; Risk Assessment; Risk Factors; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Haemodialysis vascular access dysfunction caused by aggressive venous neointimal hyperplasia is a major problem for haemodialysis patients with synthetic arteriovenous (AV) grafts. Several different strategies to prevent venous stenosis by inhibiting smooth muscle cell proliferation and migration using local delivery of potent antiproliferative agents are currently under investigation. We performed this study to evaluate the efficacy of sirolimus-eluting vascular grafts in preventing stenosis and to compare the effectiveness of sirolimus-coated grafts with that of paclitaxel-coated vascular grafts that we characterized in a previous study.. AV grafts were implanted laterally between the common carotid artery and external jugular vein of 14 female Landrace pigs. Three types of grafts were implanted: grafts coated with 1.08 μg/mm(2) sirolimus (low dose, n = 6), grafts coated with 2.41 μg/mm(2) sirolimus (high dose, n = 2) and uncoated control grafts (n = 6). Animals were sacrificed 6 weeks after surgery. Cross-sections of the venous anastomoses were analysed to determine the percentage of luminal stenosis in each group, and immunohistochemistry was performed to identify the cellular phenotypes of the neointimal hyperplasia and tissues adjacent to the implanted grafts.. Compared with the control group, neointimal hyperplasia in the venous anastomoses of the groups implanted with sirolimus-coated vascular grafts was significantly suppressed without infection. The mean ± standard error values for the percentage of luminal stenosis were 75.7 ± 12.7% in the control group and 22.2 ± 1.41% in the low-dose sirolimus-coated group. Myofibroblasts and fibroblasts were the major cell types found in the neointimal hyperplasia.. Neointimal hyperplasia was effectively suppressed by sirolimus-eluting grafts. However, the inhibitory effects of sirolimus-eluting grafts were weaker than those observed for paclitaxel-coated grafts in our previous study.

Topics: Animals; Arteriovenous Shunt, Surgical; Carotid Arteries; Cell Proliferation; Constriction, Pathologic; Female; Graft Occlusion, Vascular; Hyperplasia; Jugular Veins; Models, Animal; Neointima; Paclitaxel; Polytetrafluoroethylene; Renal Dialysis; Sirolimus; Swine; Vascular Grafting

To evaluate the effect of a polymer-free Biolimus A9-eluting stent [BioFreedom (BF)], compared with that of a biodegradable polymer-based Biolimus A9-eluting stent [BioMatrix Flex (BMF)] and a bare metal stent (BMS) in balloon denuded and radiated hypercholesterolemic rabbit iliac arteries.. Rabbits were fed with 1% cholesterol diet (n = 14) for 14 days, both iliac arteries were balloon denuded and radiated, and then rabbits were switched to 0.15% cholesterol diet. After 4 weeks, BF (n = 8), BMF (n = 8), and BMS (n = 8) were deployed in denuded and radiated areas. Four weeks later animals were euthanized, arterial segments were processed for morphometry.. The neointimal area in vessels implanted with BF stents was significantly less than that seen in vessels implanted with BMS (0.90 mm(2) ± 0.14 vs. 1.29 mm(2) ± 0.23, P <0.01). Percent fibrin and fibrin score were higher with BMF stents compared to BMS (P <0.03 and <0.04) and giant cell number was significantly higher with both BMF and BF stents (P < 0.01 for both). Percent endothelialization was significantly higher and % uncovered struts were lower with BMS compared to either BMF or BF stents (P < 0.05 for both).. This study demonstrates that compared to BMS, BF stents significantly decreased neointimal hyperplasia.

Topics: Absorbable Implants; Angioplasty, Balloon; Animals; Atherosclerosis; Cardiovascular Agents; Constriction, Pathologic; Disease Models, Animal; Drug-Eluting Stents; Fibrin; Hypercholesterolemia; Hyperplasia; Iliac Artery; Inflammation; Male; Metals; Neointima; Plaque, Atherosclerotic; Polymers; Prosthesis Design; Rabbits; Sirolimus; Stents; Time Factors

The authors investigate whether the combination of anti-CD34 antibody with DES is win-win cooperation.. DES may reduce the risk of restenosis compared to bare-metal stents (BMS), but they were found to inhibit the healing process of intima.. Fifteen BMS, 17 DES, and 16 combined anti-CD34 antibody and DES were randomly implanted in the coronary arteries of 22 minipigs. Ten minipigs were followed up to 2 weeks. The stenting coronary segments were examined by histological examination and scanning electron microscopy after in vivo coronary angiography and intracoronary optical coherence tomography (OCT) examinations. The other 12 minipigs were followed up to 3 months. Coronary angiography and intracoronary OCT examination were performed in vivo and histological examination was performed on the stenting coronary segments.. After 2 weeks, the neointimal covering level of the DES was lower than that in BMS, but the covering level of the combined stents was even better than the BMS. After 3 months, neointimal hyperplasia was significant in the BMS, but not in the other two types of stents. The in-stent late lumen loss of the combined stents even showed a decreasing tendency when compared with the DES.. The combination of anti-CD34 antibody and DES can not only well offset the short-term inhibitory effect on re-endothelialization but also slightly enhance the long-term antiproliferative effect.

Topics: Angioplasty, Balloon, Coronary; Animals; Antibodies; Antigens, CD34; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Hyperplasia; Metals; Microscopy, Electron, Scanning; Neointima; Prosthesis Design; Sirolimus; Stents; Swine; Swine, Miniature; Time Factors; Tomography, Optical Coherence

Non stent based delivery of antiproliferative agents using drug coated balloon catheters may offer additional flexibility and efficacy in a broad range of applications. The lipophilic antiproliferative drug zotarolimus makes it a potential candidate for balloon delivery. The aim of the present study was to evaluate the safety and efficacy of a prototype zotarolimus coated balloon (ZCB) catheter in comparison to a zotarolimus eluting stent (ZES) in the porcine coronary overstretch model.. Eighty-four stents (diameters 3.0 and 3.5 mm; length 15 mm) were implanted in LAD and Cx of 42 domestic pigs: control (TriMaxx, Abbott, polymer coated stent without drug, implanted with uncoated PCI catheter, n = 56); ZES (ZoMaxx, Abbott, stent coated with zotarolimus in polymer, implanted with uncoated PCI catheter, n = 14); ZCB (TriMaxx, Abbott, polymer coated stent without drug, implanted with zotarolimus coated PCI catheter, n = 14). Drug content of the vessel wall (n = 9) was measured about 10-30 min post intervention with ZCB in additional pigs.. Immediately after ZCB treatment 101 ± 31 μg of zotarolimus was detected in the coronary arteries. After 28 days ZES led to a reduction of neointimal area from 4.32 ± 1.45 to 3.32 ± 1.11 mm2 (P = 0.019 vs. control). The effect of neointimal inhibition was more pronounced with the novel ZCB (2.79 ± 1.43 mm², P = 0.001 vs. control). Inflammation score was significantly reduced in vessels treated with the ZCB (0.75 ± 0.86 compared to control (1.45 ± 0.94, P = 0.013) and ZES (1.65 ± 0.90, P = 0.012).. Zotarolimus coated balloons and stents were found to effectively reduce neointimal proliferation in the porcine coronary model. Inflammation scores were significantly reduced after treatment with the coated balloon. Zotarolimus balloon coating might be a novel option in preventing and treating restenosis.

Topics: Angioplasty, Balloon, Coronary; Animals; Coronary Restenosis; Coronary Vessels; Disease Models, Animal; Drug-Eluting Stents; Hyperplasia; Neointima; Sirolimus; Swine

Topics: Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Equipment Failure; Humans; Hyperplasia; Neointima; Sirolimus; Tomography, Optical Coherence

The main complication of aortocoronary reconstruction with vein grafts is restenosis in the course of time. The aim was to assess the effect of a periadventitial polyester mesh releasing sirolimus on intimal hyperplasia of autologous grafts. We implanted v. jugularis ext. into a. carotis communis in rabbits. The vein graft was either intact, or was wrapped with a pure polyester mesh, or with a sirolimus-releasing mesh. Three and six weeks after surgery, the veins were subjected to standard histological staining and the thicknesses of the tunica intima, the media and the intima-media complex were measured. Wrapping the vein with a mesh releasing sirolimus or with a pure mesh decreased the thickness of the intima in comparison with a vein graft by 73 ± 11% or 73 ± 8% after 3 weeks, and by 73 ± 9% or 59 ± 12% after 6 weeks, respectively. Sirolimus-releasing meshes reduced the thickness of the media by 65 ± 9% and 20 ± 12% after 3 and 6 weeks. The thickness of the intima-media complex in grafts with sirolimus-releasing meshes decreased by 60 ± 6% and 30 ± 13% in comparison with pure PES meshes, after 3 and 6 weeks, respectively. A periadventitial polyester mesh releasing sirolimus has the potential to become an effective device in preventing vein graft restenosis.

Topics: Animals; Cell Count; Cell Proliferation; Chinchilla; Drug Implants; Graft Occlusion, Vascular; Hyperplasia; Immunohistochemistry; Immunosuppressive Agents; Male; Muscle, Smooth, Vascular; Paraffin Embedding; Polyesters; Proliferating Cell Nuclear Antigen; Rabbits; Sirolimus; Surgical Mesh; Tissue Fixation; Tunica Intima; Tunica Media; Veins

Synthetic arteriovenous (AV) hemodialysis grafts are plagued by hyperplasia resulting in occlusion and graft failure yet there are no clinically available preventative treatments. Here the delivery and degradation of a sirolimus-laden polymer gel were monitored in vivo by magnetic resonance imaging (MRI) and its efficacy for inhibiting hyperplasia was evaluated in a porcine model of AV graft stenosis. Synthetic grafts were placed between the carotid artery and ipsilateral jugular vein of swine. A biodegradable polymer gel loaded with sirolimus (2.5mg/mL) was immediately applied perivascularly to the venous anastomosis, and reapplied by ultrasound-guided injections at one, two and three weeks. Control grafts received neither sirolimus nor polymer. The lumen cross-sectional area at the graft-vein anastomosis was assessed in vivo by non-invasive MRI. The explanted tissues also underwent histological analysis. A specifically developed MRI pulse sequence provided a high contrast-to-noise ratio (CNR) between the polymer and surrounding tissue that allowed confirmation of gel location after injection. Polymer signal decreased up to 80% at three to four weeks after injection, slightly faster than its degradation kinetics in vitro. The MR image of the polymer was confirmed by visual assessment at necropsy. On histological assessment, the mean hyperplasia surface area of the treated graft was 52% lower than that of the control grafts (0.43mm(2) vs. 0.89mm(2); p<0.003), while the minimum cross-sectional lumen area, as measured on MRI, was doubled (5.3mm(2) vs 2.5mm(2); p<0.05). In conclusion, customized MRI allowed non-invasive monitoring of the location and degradation of drug delivery polymer gels in vivo. Perivascular application of sirolimus-laden polymer yielded a significant decrease in hyperplasia development and an increase in lumen area at the venous anastomosis of AV grafts.

Topics: Animals; Antibiotics, Antineoplastic; Drug Carriers; Gels; Graft Occlusion, Vascular; Hyperplasia; Polyethylene Glycols; Polyglactin 910; Renal Dialysis; Sirolimus; Sus scrofa

Delayed endothelialization contributes to stent thrombosis of current drug-eluting stents. The asymmetrical coating technique provides an anti-proliferative effect abluminally without affecting luminal endothelialization. Layer-by-layer self-assembled chitosan/heparin (C/H LBL) has been proved to promote re-endothelialization. A novel stent system, C/H LBL coated luminally and sirolimus released abluminally (C/H LBL-SES), was fabricated.. Bare metal stents (BMS), traditionally circumferential sirolimus-eluting stents (SES), and C/H LBL-SES were implanted into porcine coronary arteries. At the 7, 14 and 28 days follow-up (FU), angiography, intravascular ultrasound (IVUS), vasomotor function induced by acetylcholine (Ach), scanning-electron microscopy and histopathology were performed. Remodeling index (RI) was based on IVUS and defined as cross-sectional area (CSA) of vessel at in-stent segment divided by CSA of reference vessel and expressed as a percentage with a normal range from 0.95 to 1.05.. Thirty-eight mini pigs were enrolled and 74 stents (BMS = 23, C/H LBL = 28, SES = 23) were implanted in this study. At 28 days after implantation, the diameter stenosis of C/H LBL-SES by quantitative coronary angiography was 18.8 ± 2.5 %, the area stenosis by histomorphometry was 24.2 ± 2.9 %, which were comparable to that of SES and superior to BMS. At 14 days, re-endothelialization of C/H LBL-SES was almost completed, while only about 50 % of surface of SES was covered by endothelium. At 7, 14 and 28 days FU, although C/H LBL-SES suffered a greater vasoconstriction induced by Ach infusion than BMS (P < 0.05), it behaved better than SES (P < 0.01). No sign of stent malapposition was detected, while RI was within the normal range by IVUS. No acute or subacute thrombotic events occurred in all three groups.. The asymmetrically designed C/H LBL-SES successfully inhibited neointima hyperplasia, while diminishing vasoconstriction after Ach-stress. Endothelialization of C/H LBL-SES was less affected compared with traditionally circumferentially coated SES.

Topics: Acetylcholine; Animals; Cardiovascular Agents; Chitosan; Coated Materials, Biocompatible; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Disease Models, Animal; Drug-Eluting Stents; Endothelial Cells; Heparin; Hyperplasia; Metals; Microscopy, Electron, Scanning; Neointima; Percutaneous Coronary Intervention; Prosthesis Design; Sirolimus; Swine; Swine, Miniature; Time Factors; Ultrasonography, Interventional; Vasoconstriction

Recent studies have reported the development of neoatherosclerosis inside stents and subsequent acute coronary syndrome secondary to disruption of neointimal hyperplasia. The aim of the study was to compare the characteristics of neointimal hyperplasia and its time course between bare metal stents (BMSs) and drug-eluting stents (DESs) using optical coherence tomography. A total of 138 stents were divided into 3 groups according to the follow-up period: early phase, <9 months (25 BMSs and 27 DESs); intermediate phase, ≥9 and <48 months (18 BMSs and 43 DESs); and delayed phase, ≥48 months (13 BMSs and 12 DESs). Optical coherence tomographic analysis included the presence of lipid-laden intima, percentage of lipid-rich plaque, and signal attenuation. The optical coherence tomographic findings were compared between the BMSs and DESs in each period, and the difference between the periods was also determined. In the early phase, a greater incidence of lipid-laden plaque (37% vs 8%, p = 0.02) and a greater percentage of lipid-rich plaque (12.9 ± 25.1% vs 1.2 ± 4.3%, p = 0.01) were found in the DESs than in the BMSs. In the intermediate phase, the DES group continuously showed a significantly greater incidence of lipid-laden plaque (63% vs 28%, p = 0.03) and greater percentage of lipid-rich plaque (24.8 ± 28.1% vs 4.1 ± 7.3%, p <0.01). In addition, signal attenuation was greater in the DES group, suggesting early changes in neointimal hyperplasia properties. In the delayed phase, lipid-laden plaque was the predominant type in both groups. In conclusion, lipid-rich neoatherosclerosis develops inside stents earlier in DESs than in BMSs. After 48 months, most restenotic stents will have developed lipid-laden neointima in both groups.

Topics: Acute Coronary Syndrome; Atherosclerosis; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Incidence; Male; Massachusetts; Middle Aged; Myocardial Ischemia; Myocardial Revascularization; Neointima; Sirolimus; Time Factors; Tomography, Optical Coherence

A novel self-expanding, drug-eluting stent (DES) was designed to slowly release everolimus in order to prevent restenosis after percutaneous peripheral intervention. The purpose of this experimental animal study was to test the hypothesis that long-term local, stent-mediated delivery of everolimus would reduce neointimal hyperplasia in porcine iliac arteries.. The iliac arteries of 24 Yucatan mini-swine were percutaneously treated with overlapping 8- × 28-mm self-expanding nitinol stents loaded with everolimus (225 μg/cm2 stent surface area) formulated in a poly(ethylene-co-vinyl alcohol) copolymer intended to deliver the drug in a sustained fashion over about 6 months (DES). Bare nitinol self-expanding stents (bare metal stent [BMS]) were implanted in an identical fashion on the contralateral side to serve as controls. After 3, 6, or 12 months, the animals were sacrificed and the stented arteries perfusion-fixed for histomorphometric analysis.. The chronic presence of everolimus in arterial tissue reduced stent-induced inflammation after 3 months (inflammation score: BMS 2.29±0.44 vs DES 0.17±0.17; P=.001) and 6 months (BMS 2.06±0.43 vs DES 0.50±0.5; P=.007), although some late inflammation was observed after drug exhaustion (BMS 1.00±0.25 vs DES 2.56±0.62 after 12 months; P=not significant [NS]). Treatment with locally delivered everolimus significantly reduced neointimal hyperplasia after 3 months (neointimal thickness: BMS 0.79±0.20 vs DES 0.37±0.04 mm; P=.03) and 6 months (BMS 0.73±0.14 vs DES 0.41±0.08 mm; P=.05), although the effect had dissipated after 12 months (BMS 0.68±0.11 vs DES 0.67±0.11 mm; P=NS). Remarkably, stent-induced neoatherosclerosis, characterized by the histologic presence of foamy macrophages and cholesterol clefts, was significantly attenuated by treatment with everolimus (atherogenic change scores at 3 months: BMS 0.56±0.15 vs DES 0.04±0.04; P=.003; 6 months: BMS 0.84±0.23 vs DES 0.00±0.00; P=.004; and 12 months: BMS 0.09±0.10 vs DES 0.19±0.19; P=NS).. In this experimental animal model, local arterial stent-mediated delivery of everolimus inhibited the formation of neointimal hyperplasia and neoatherosclerosis during the first 6 months. The effect was transient, however, as arterial morphology and histology appeared similar to control stented arteries after 12 months.

Topics: Animals; Atherosclerosis; Disease Models, Animal; Drug-Eluting Stents; Endovascular Procedures; Everolimus; Graft Occlusion, Vascular; Hyperplasia; Iliac Artery; Immunosuppressive Agents; Neointima; Sirolimus; Swine; Swine, Miniature

Topics: Angina, Unstable; Cardiovascular Agents; Coronary Angiography; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Humans; Hyperplasia; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prosthesis Design; Sirolimus; Thrombectomy; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Stent-based delivery of sirolimus has been shown to reduce neointimal hyperplasia significantly. However, the long-term effect of the polymer is thought to initiate and sustain an inflammatory response and contribute to the occurrence of late complications. Our study aimed to evaluate the efficacy and safety of the BuMA biodegradable drug-coated sirolimus-eluting stent (BSES) for inhibiting neointimal hyperplasia in a porcine coronary model.. Four types of stents were implanted at random in different coronary arteries of the same pig: BSES (n = 24), bare metal stent (BMS) (n = 24), biodegradable polymer coated stent without drug (PCS) (n = 24) and only poly (n-butyl methacrylate) base layer coated stent (EGS) (n = 23). In total, 26 animals underwent successful random placement of 95 oversized stents in the coronary arteries. Coronary angiography was performed after 28 days, 90 days and 240 days of stent implantation. After 14 days, 28 days, 90 days and 240 days, 6 animals at each timepoint were sacrificed for histomorphologic analysis.. The 28-day, 90-day and 240-day results of quantitative coronary angiography (QCA) showed reduction in luminal loss (LL) in the BSES group when compared with the BMS group; (0.20 ± 0.35) mm vs. (0.82 ± 0.51) mm (P = 0.035), (0.20 ± 0.30) mm vs. (0.93 ± 0.51) mm (P = 0.013), and (0.18 ± 0.16) mm vs. (0.19 ± 0.24) mm (P = 0.889), respectively. By 28-day, 90-day and 240-day histomorphomeric analysis results, there was also a corresponding significant reduction in neointimal tissue proliferation with similar injury scores of BSES compared with the BMS control; average neointimal area (0.90 ± 0.49) mm(2) vs. (2.16 ± 1.29) mm(2) (P = 0.049), (1.53 ± 0.84) mm(2) vs. (3.41 ± 1.55) mm(2) (P = 0.026), and (2.43 ± 0.95) mm(2) vs. (3.12 ± 1.16) mm(2) (P = 0.228), respectively. High magnification histomorphologic examination revealed similar inflammation scores and endothelialization scores in both the BSES and BMS groups.. The BuMA biodegradable drug-coated sirolimus-eluting stents can significantly reduce neointimal hyperplasia and in-stent restenosis. Re-endothelialization of the BuMA stent is as good as that of the BMS in the porcine coronary model due to the reduced inflammation response to the BuMA stent.

Topics: Absorbable Implants; Animals; Coronary Angiography; Drug-Eluting Stents; Female; Hyperplasia; Neointima; Polymers; Sirolimus; Swine

Despite the expressive reduction in the intimal hyperplasia (IH) formation after DES implantation at the mid-term, late restenosis has been recently noticed. Our objective was to determine, by means of serial angiography (QCA) and intravascular ultrasound (IVUS) at two different time points, whether the occurrence of the "late catch-up" phenomenon occurs after sirolimus-eluting stent (SES) implantation. Thirty-eight non-complex patients treated with a single 18-mm SES who had systematic serial QCA and IVUS analyses at mean 8 and 20 months were enrolled. Primary endpoint is to evaluate the temporal course of IH formation after SES implantation, by comparing QCA in-stent late loss and IVUS percent IH obstruction between the invasive follow-ups. Mean cohort age was 59.3 years and 31.6% were diabetics. Baseline reference vessel diameter was 2.8 ± 0.4 mm and lesion length was 11.5 ± 3.5 mm. Left anterior descending artery was the most frequent target vessel (55.3%). Between 8 and 20 months, a non-significant increase in in-stent late loss from 0.10 ± 0.18 to 0.15 ± 0.30 mm (P = 0.38) was observed. By IVUS, a slight increase in the percent IH obstruction (1.03 ± 2.13 to 1.76 ± 1.87%, P = 0.12) was detected between the two evaluations. Interestingly, all the neoformed tissue accrued from 8 to 20 months accumulated in the distal portion of the stent. In the non-complex scenario, SES implantation was associated with a minimal, non-significant increase in the IH volume between 8 and 20 months.

Topics: Aged; Analysis of Variance; Angioplasty, Balloon, Coronary; Brazil; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Predictive Value of Tests; Prosthesis Design; Risk Assessment; Risk Factors; Sirolimus; Time Factors; Tomography, X-Ray Computed; Treatment Outcome; Ultrasonography, Interventional

Optical coherence tomography is a high-resolution imaging technology that allows in vivo assessment of neointimal hyperplasia and strut coverage after coronary stenting.. Assessment of spatial distribution of healing, 6 months after zotarolimus-eluting stent implantation.. Forty-two zotarolimus-eluting stents were monitored by optical coherence tomography 6 months after implantation. Mean neointimal strut coverage thickness and percentage of neointimal hyperplasia were measured every millimetre. Non-covered strut ratios were assessed on each slice. In addition, the spatial distribution of neointimal hyperplasia and strut coverage were analysed longitudinally on five stent segments and axially on each slice.. There were no clinical events at 6 months under dual antiplatelet therapy. The optical coherence tomography analysis showed a mean neointimal hyperplasia thickness of 333±147μm and neointimal hyperplasia obstruction of 36.1±12.3%. The percentage of covered struts at 6 months was very high (98.9%). Only 6/745 slices analysed (0.8%) had non-covered strut ratios exceeding 30%. There was no significant heterogeneity in either longitudinal or axial neointimal hyperplasia distribution. No thrombi were observed.. This optical coherence tomography study found relatively constant neointimal hyperplasia thickness, regardless of the zotarolimus-eluting stent length or diameter. This spatially homogeneous neointimal hyperplasia was associated with near-total coverage of all struts, 6 months after implantation.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Drug Therapy, Combination; Drug-Eluting Stents; Female; France; Humans; Hyperplasia; Male; Middle Aged; Platelet Aggregation Inhibitors; Prospective Studies; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome; Tunica Intima

Nanoparticles (NPs) possess several advantages as a carrier system for intracellular delivery of therapeutic agents. Rapamycin is an immunosuppressive agent which also exhibits marked antiproliferative properties. We investigated whether rapamycin-loaded NPs can reduce neointima formation of vein graft disease in a rat model.. Poly(lactic-co-glycolic acid) (PLGA) NPs-containing rapamycin was prepared using an oil/water solvent evaporation technique. The size and morphology of the NP were determined by dynamic light scattering methodology and electron microscopy. In vitro cytotoxicity of blank, rapamycin-loaded PLGA NPs was studied using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Excised rat jugular vein was treated ex vivo with blank NPs, or rapamycin-loaded NPs, and then interposed back into the carotid artery position using a cuff technique. Grafts were harvested for 21 days and subjected to morphometric analysis as well as immunohistochemical analysis and Western blotting.. Rapamycin was efficiently loaded in PLGA NPs with an encapsulation efficiency of 87.6%. The average diameter of NPs was 180.3 nm. The NPs-containing rapamycin at 1 ng/mL significantly inhibited vascular smooth muscular cells proliferation. Measurement of rapamycin levels in vein grafts showed that the concentration of rapamycin in vein grafts at 3 weeks after grafting was 0.9 ± 0.1 μg/g. In grafted veins without treatment, intima-media thickness was 300.4 ± 181.5 μm at 21 days after grafting, whereas veins treated with rapamycin-loaded NPs showed a reduction of intimal-media thickness of 150.2 ± 62.5 μm (p = 0.001). Cell proliferation was measured by proliferating cell nuclear antigen immunohistochemistry staining. As expected, proliferating cell nuclear antigen index declined from 83.4% ± 7.4% to 66.2% ± 4.5% in vein grafts after 3 weeks (p = 0.002). Platelet endothelial cell adhesion molecule (PECAM-1/CD31) staining was used to measure luminal endothelial coverage in grafts and indicated a high level of endothelialization at 21 days after grafting, with no significant effect of blank or rapamycin-loaded NPs group. Western blot analysis showed that treatment with rapamycin-loaded PLGA NPs markedly attenuated phosphorylation and activation of S6 kinase 1 phosphorylation and inactivation of 4E (eIF4E)-binding protein 1, both in vascular smooth muscular cells and vein grafts at 7 and 21 days after grafting.. We conclude that sustained-release rapamycin from rapamycin-loaded NPs inhibits vein graft thickening without affecting the endothelial cells in rat carotid vein-to-artery interposition grafts; thus, this may be a promising therapy for the treatment of vein graft disease.

Topics: Animals; Blotting, Western; Cardiovascular Agents; Carotid Arteries; Carrier Proteins; Cell Proliferation; Cells, Cultured; Delayed-Action Preparations; Drug Carriers; Endothelial Cells; Graft Survival; Hyperplasia; Immunohistochemistry; Intracellular Signaling Peptides and Proteins; Jugular Veins; Lactic Acid; Light; Male; Microscopy, Electron, Transmission; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nanoparticles; Phosphoproteins; Phosphorylation; Platelet Endothelial Cell Adhesion Molecule-1; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases; Scattering, Radiation; Sirolimus; Solubility; Tunica Intima; Vascular Grafting

Nanoparticles possess several advantages as a carrier system for intracellular delivery of therapeutic agents. Rapamycin is an immunosuppressive agent which also exhibits marked antiproliferative properties. We investigated whether rapamycin-loaded nanoparticles(NPs) can reduce neointima formation in a rat model of vein graft disease.. Poly(lactic-co-glycolic acid) (PLGA) NPs containing rapamycin was prepared using an oil/water solvent evaporation technique. Nanoparticle size and morphology were determined by dynamic light scattering methodology and electron microscopy. In vitro cytotoxicity of blank, rapamycin-loaded PLGA (RPLGA) NPs was studied using MTT Assay. Excised rat jugular vein was treated ex vivo with blank-NPs, or rapamycin-loaded NPs, then interposed back into the carotid artery position using a cuff technique. Grafts were harvested at 21 days and underwent morphometric analysis as well as immunohistochemical analysis.. Rapamycin was efficiently loaded in PLGA nanoparticles with an encapsulation efficiency was 87.6%. The average diameter of NPs was 180.3 nm. The NPs-containing rapamycin at 1 ng/ml significantly inhibited vascular smooth muscular cells proliferation. Measurement of rapamycin levels in vein grafts shown that the concentration of rapamycin in vein grafts at 3 weeks after grafting were 0.9 ± 0.1 μg/g. In grafted veins without treatment intima-media thickness was 300.4 ± 181.5 μm after grafting 21 days. Whereas, Veins treated with rapamycin-loaded NPs showed a reduction of intimal-media thickness of 150.2 ± 62.5 μm (p = 0.001). CD-31 staining was used to measure luminal endothelial coverage in grafts and indicated a high level of endothelialization in 21 days vein grafts with no significant effect of blank or rapamycin-loaded NPs group.. We conclude that sustained-release rapamycin from rapymycin loaded NPs inhibits vein graft thickening without affecting the reendothelialization in rat carotid vein-to-artery interposition grafts and this may be a promising therapy for the treatment of vein graft disease.

Topics: Animals; Anti-Bacterial Agents; Disease Models, Animal; Endothelium, Vascular; Graft Survival; Hyperplasia; Jugular Veins; Male; Microscopy, Electron, Transmission; Muscle, Smooth, Vascular; Nanoparticles; Neointima; Rats; Rats, Sprague-Dawley; Sirolimus

It has been suggested that sirolimus-eluting stents (SES) provoke a more sustained inflammatory response (IR) in neointimal hyperplasia (NIH). The purpose of this study was to compare morphological vessel characteristics, including post-stent IR in NIH, between patients with SES and bare metal stents (BMS) using optical coherence tomography (OCT).. Thirty-seven patients underwent OCT at their post-stent follow-up. OCT signal-intensity deviation (normalized standard-deviation; OCT-NSD) values in NIH were compared between the 2 groups. In addition, the serum concentration of high-sensitivity C-reactive protein (hs-CRP) was measured. Stent-malapposition rate (1.78% vs. 0.7%; P = 0.016), uncovered stent-strut rate (16% vs. 3.7%; P = 0.0002), peri-stent ulcer like appearance (PSUA; 50% vs. 0%; P = 0.006) were all significantly higher in the SES group than in the BMS group, respectively. The OCT-NSD value was also significantly higher in the SES group than in the BMS group (0.213 ± 0.005 vs. 0.198 ± 0.005; P < 0.001), as was the hs-CRP level (2.54 ± 1.89 vs. 0.64 ± 0.3 mg/L; P = 0.0006). In addition, a significant positive correlation was found between hs-CRP and OCT-NSD (r = 0.471; P = 0.0025).. PSUA-morphology was specific in the SES group, and higher levels of OCT-NSD and hs-CRP after SES implantation suggest sustained IR in NIH compared with following BMS implantation. These different characteristics may be some of the background that promotes thrombus formation as a late-stage post-stent complication of SES.

Topics: Aged; Angioplasty, Balloon, Coronary; Biomarkers; C-Reactive Protein; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Inflammation; Male; Metals; Middle Aged; Neointima; Sirolimus; Stents; Tomography, Optical Coherence; Ultrasonography, Interventional

To determine the efficacy of sirolimus-eluting bioabsorbable magnesium alloy stents (SEBMAS) in restenosis prevention.. A balloon-expandable bioabsorbable magnesium alloy stent (BMAS) was created and coated with biodegradable poly(lactic acid-co-trimethylene carbonate) that contained the antiproliferative drug sirolimus (140 ± 40 µg/cm²). Both the uncoated BMAS and the coated SEBMAS were deployed 2 cm apart in balloon-injured infrarenal abdominal aortas of 20 New Zealand white rabbits. The stented aortic segments were removed at 30, 60, 90, and 120 days (5 rabbits per interval) after implantation. The average stent strut sectional area of each group was measured to evaluate the degree of magnesium corrosion and to forecast the biodegradation time profile of the magnesium stent. Histology and histopathology of the sectioned stented aortic segments were performed to evaluate neointima formation, endothelialization, and inflammation.. The SEBMAS degraded gradually after being implanted into the rabbit aorta, and total biocorrosion occurred after ~120 days. In all groups, the lumen area was significantly greater, but the neointimal area was significantly smaller in SEBMAS segments compared with the uncoated BMAS segments (p < 0.05) at all time points. There was no significant difference in the injury or inflammation scores between the groups. Endothelialization was delayed at 30 days in the SEBMAS segments vs. the uncoated BMAS segments.. SEBMAS further reduces intimal hyperplasia and improves the lumen area when compared to uncoated BMAS; however, it delays vascular healing and endothelialization.

Topics: Alloys; Angioplasty; Animals; Aorta, Abdominal; Aortic Diseases; Arterial Occlusive Diseases; Cardiovascular Agents; Cell Proliferation; Coated Materials, Biocompatible; Constriction, Pathologic; Dioxanes; Disease Models, Animal; Drug-Eluting Stents; Endothelial Cells; Hyperplasia; Lactic Acid; Magnesium; Male; Polyesters; Polymers; Prosthesis Design; Rabbits; Secondary Prevention; Sirolimus; Time Factors; Wound Healing

Aberrant activation of phosphoinositide-3-kinase (PI3K)/Akt signaling has been implicated in the development and progression of multiple human cancers. During the process of skin tumor promotion induced by treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), activation of epidermal Akt occurs as well as several downstream effectors of Akt, including the activation of mTORC1. Rapamycin, an established mTORC1 inhibitor, was used to further explore the role of mTORC1 signaling in epithelial carcinogenesis, specifically during the tumor promotion stage. Rapamycin blocked TPA-induced activation of mTORC1 as well as several downstream targets. In addition, TPA-induced epidermal hyperproliferation and hyperplasia were inhibited in a dose-dependent manner with topical rapamycin treatments. Immunohistochemical analyses of the skin from mice in this multiple treatment experiment revealed that rapamycin also significantly decreased the number of infiltrating macrophages, T cells, neutrophils, and mast cells seen in the dermis following TPA treatment. Using a two-stage skin carcinogenesis protocol with 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as the promoter, rapamycin (5-200 nmol per mouse given topically 30 minutes prior to TPA) exerted a powerful antipromoting effect, reducing both tumor incidence and tumor multiplicity. Moreover, topical application of rapamycin to existing papillomas induced regression and/or inhibited further growth. Overall, the data indicate that rapamycin is a potent inhibitor of skin tumor promotion and suggest that signaling through mTORC1 contributes significantly to the process of skin tumor promotion. The data also suggest that blocking this pathway either alone or in combination with other agents targeting additional pathways may be an effective strategy for prevention of epithelial carcinogenesis.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antibiotics, Antineoplastic; Anticarcinogenic Agents; Blotting, Western; Carcinogens; Humans; Hyperplasia; Mice; Neoplasm Staging; Papilloma; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Skin Neoplasms; Tetradecanoylphorbol Acetate; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Autologous vein grafts used as aortocoronary bypasses are often prone to intimal hyperplasia, which results in stenosis and occlusion of the vein. The aim of this study was to prevent intimal hyperplasia using a newly developed perivascular system with sustained release of sirolimus. This system of controlled drug release consists of a polyester mesh coated with a copolymer of L-lactic acid and epsilon-caprolactone that releases sirolimus. The mesh is intended for wrapping around the vein graft during surgery. The mesh releasing sirolimus was implanted in periadventitial position onto arteria carotis communis of rabbits, and neointimal hyperplasia was then assessed. We found that implanted sirolimus-releasing meshes reduced intima thickness by 47+/-10 % compared to a vein graft after 3 weeks. The pure polyester mesh decreased vein intima thickness by 35+/-9 %. Thus, our periadventitial system for controlled release of sirolimus prevented the development of intimal hyperplasia in autologous vein grafts in vivo in rabbits. A perivascularly applied mesh releasing sirolimus is a promising device for preventing stenosis of autologous vein grafts.

Topics: Animals; Cardiovascular Agents; Cell Proliferation; Drug Carriers; Graft Occlusion, Vascular; Hyperplasia; Jugular Veins; Polyesters; Rabbits; Sirolimus; Tunica Intima

Drug-eluting stents proved to minimize neointimal hyperplasia in coronary vessels. Hyperplastic reaction is the most common unwelcome event related to the use of metal mesh stents in the ureter. We evaluated the effect of zotarolimus-eluting stent (ZES) Endeavor Resolute in the porcine and rabbit ureter.. A ZES and a bare metal stent (BMS) were inserted in each ureter of 10 pigs and 6 rabbits. The insertion was performed by the retrograde approach. CT was used for the evaluation of porcine ureters while intraoperative intravenous urography (IVU) was used for rabbit ureters. The follow-up included CT or IVU every week for the following 4 weeks for pigs and 8 weeks for rabbits. Renal scintigraphies were performed before stent insertion and during the third week in all animals. Optical coherence tomography (OCT) has been used for the evaluation of the luminal and intraluminal condition of the ureters with stents. Histopathologic examination of the these ureters embedded in glycol-methacrylate was performed.. Hyperplastic reaction was present in both stent types. BMSs in seven porcine ureters were completely obstructed while porcine ureters with ZES stents had hyperplastic tissue that did not result in obstruction. Two rabbit ureters with BMS stents were occluded while no ZES was associated with ureteral obstruction. The function of the seven porcine renal units and the two rabbit units with obstructed ureters with stents was compromised. The OCT revealed increased hyperplastic reaction in the ureters with BMS stents in comparison with those with ZESs. Although, hyperplastic reaction was present in all cases, pathologic examination revealed significantly more hyperplastic reaction in BMSs.. ZESs in the pig and rabbit ureter were not related to hyperplastic reaction resulting in stent occlusion. These stents were related to significantly lower hyperplastic reaction in comparison with BMSs while inflammation rates were similar for both stent types.

Topics: Animals; Drug-Eluting Stents; Female; Hyperplasia; Inflammation; Kidney; Metals; Prosthesis Implantation; Rabbits; Radionuclide Imaging; Sirolimus; Sus scrofa; Tomography, Optical Coherence; Tomography, X-Ray Computed; Ureter; Urography; Urothelium

Although the use of drug-eluting stents (DES) has been shown to limit neointimal hyperplasia in clinical coronary artery disease treatment, currently available DES may adversely affect re-endothelialization (RE) and thus increase fateful stent thrombosis. As stromal cell derived factor 1a (SDF-1a) plays an essential role in the regulation of endothelial progenitor cells (EPCs) mobilization, homing, and differentiation in response to vascular injury, we assumed that SDF-1a may enhance EPCs adhesion and attenuate delayed RE associated with DES.. Biologically active recombinant human SDF-1a (rhSDF-1a) was first produced using an Escherichia coli expression system. Twenty-four male rabbits were then underwent sirolimus-eluting stents implantation in aorta abdominalis. After operation, they were randomly divided into two groups and subcutaneously injected daily with 50 μg/kg rhSDF-1a or the same volume of saline for 7 days.. With the application of scanning electron microscopy (SEM) and histological analysis, we found that rhSDF-1a significantly promoted RE on days 7, 14, 28 and inhibited neointimal hyperplasia on day 28 after stent implantation.. Our results revealed a potential role of rhSDF-1a in facilitating RE and inhibiting neointimal proliferation after DES implantation, leading to a conclusion that this protein may be a potential candidate agent for the treatment of in-stent restenosis and stent thrombosis.

Topics: Animals; Aorta, Abdominal; Chemokine CXCL12; Drug-Eluting Stents; Endothelium, Vascular; Humans; Hyperplasia; Male; Microscopy, Electron, Scanning; Neointima; Rabbits; Recombinant Proteins; Sirolimus; Time Factors

To clarify the specific molecular events of progressive tubular damage in chronic renal failure (CRF), we conducted microarray analyses using isolated proximal tubules from subtotally nephrectomized (Nx) rats as a model of CRF. Our results clearly demonstrated time-dependent changes in gene expression profiles localized to proximal tubules. The expression of mitosis-specific genes Cyclin B2 and Cell division cycle 2 (Cdc2) was significantly and selectively increased in the proximal tubules during the compensated period but decreased to basal level in the end-stage period. Administration of everolimus, a potent inhibitor of mammalian target of rapamycin, markedly reduced compensatory hypertrophy and hyperplasia of epithelial cells, which was accompanied by complete abolishment of the expression of Cyclin B2 and Cdc2 enhancement; renal function was then severely decreased. Treatment with the Cdc2 inhibitor 2-cyanoethyl alsterpaullone clearly decreased epithelial cell hyperplasia, based on staining of phosphorylated histone H3 and Ki-67, while hypertrophy was not inhibited. In conclusion, we have demonstrated roles of Cyclin B2 and Cdc2 in the epithelial hyperplasia in response to Nx. These results advance the knowledge of the contribution of cell cycle regulators, especially M phase, in pathophysiology of tubular restoration and/or degeneration, and these two molecules are suggested to be a marker for the proliferation of proximal tubular cells in CRF.

Topics: Animals; CDC2 Protein Kinase; Cell Cycle; Cell Cycle Proteins; Cyclin B2; Cyclin-Dependent Kinases; Everolimus; Hyperplasia; Immunosuppressive Agents; Intracellular Signaling Peptides and Proteins; Kidney Failure, Chronic; Kidney Tubules; Male; Mitosis; Protein Array Analysis; Protein Serine-Threonine Kinases; Rats; Rats, Wistar; Reproducibility of Results; Sirolimus; TOR Serine-Threonine Kinases; Up-Regulation

This study reports on a dual drug-eluting stent (DDES) that has an anti-proliferative and an anti-thrombotic in a biodegradable polymer-coated onto a cobalt-chromium stent. The DDES was prepared by spray coating the bare metal stent with a biodegradable polymer loaded with sirolimus and triflusal, to treat against restenosis and thrombosis, respectively. The 2-layered dual-drug coated stent was characterized in vitro for surface properties before and after expansion, as well as for possible delamination by cross-sectioning the stent in vitro. The in vitro anti-platelet behavior of the triflusal-loaded films was investigated by using dynamic platelet adhesion measurements. Additionally, the in vitro degradation and release study of the films and the stents w/single sirolimus and dual sirolimus-triflusal in different formulations were examined. Finally, in vivo studies (in a porcine carotid artery model) were performed for acute thrombosis, inflammation and restenosis at 30 days. The in vitro results show DDES can sustain release both anti-proliferation drug (sirolimus) and anti-thrombosis drug (triflusal), two drugs were controlled in different rates to effectively reduce thrombosis and proliferation at the same time. In vivo results show a significant reduction in restenosis with dual-drug eluting stent compared with the controls (a bare metal stent, a sirolimus coated and a pure polymer-coated stent). The reduction in restenosis with a dual sirolimus-triflusal eluting stent is associated with an inhibition of inflammation, especially thrombus formation, suggesting that such dual-drug eluting stents have a role to play for the treatment of coronary artery disease.

Topics: Animals; Antibiotics, Antineoplastic; Coated Materials, Biocompatible; Drug Delivery Systems; Drug-Eluting Stents; Humans; Hyperplasia; Materials Testing; Platelet Adhesiveness; Platelet Aggregation Inhibitors; Salicylates; Sirolimus; Surface Properties; Swine; Thrombosis

Regenerative capacity is progressively lost with age. Here we show that pregnancy markedly improved liver regeneration in aged mice concomitantly with inducing a switch from proliferation-based liver regeneration to a regenerative process mediated by cell growth. We found that the key mediator of this switch was the Akt/mTORC1 pathway; its inhibition blocked hypertrophy, while increasing proliferation. Moreover, pharmacological activation of this pathway sufficed to induce the hypertrophy module, mimicking pregnancy. This treatment dramatically improved hepatic regenerative capacity and survival of old mice. Thus, cell growth-mediated mass reconstitution, which is relatively resistant to the detrimental effects of aging, is employed in a physiological situation and holds potential as a therapeutic strategy for ameliorating age-related functional deterioration.

Topics: Aging; Animals; Antibiotics, Antineoplastic; Cell Proliferation; Female; Hepatectomy; Hepatocytes; Hyperplasia; Hypertrophy; Liver; Liver Regeneration; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Multiprotein Complexes; Pregnancy; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

This study aimed to evaluate the impact of angiographic and intravascular ultrasound (IVUS) features on clinical outcome in nondiabetic and type 2 diabetic patients after percutaneous coronary intervention (PCI) with sirolimus-eluting stent (SES) implantation.. Repeat coronary angiography with IVUS imaging was performed after SES-based PCI for de-novo lesions in 128 diabetic and 327 nondiabetic patients (189 lesions and 504 lesions, respectively). The rate of major adverse cardiac events including cardiac death, non fatal myocardial infarction (MI), and target lesion revascularization during clinical follow-up was recorded.. In-stent and in-segment late loss, intimal hyperplasia volume, and percentage volumetric obstruction were similar, but stented external elastic membrane cross-sectional area and reference/stented segment ratio were lower in diabetic than in nondiabetic patients. Incomplete stent apposition (ISA) was less frequent, but occurrence of new coronary lesions was higher in diabetic than in nondiabetic patients. Despite similar target lesion revascularization, cumulative survival rates freedom from composite cardiac death and nonfatal MI or major adverse cardiac events were reduced in diabetic patients. Cox proportional hazards model identified diabetes, left ventricular ejection fraction, minimal stent CSA, maximal ISA area, atherosclerotic progression and lesion length as independent predictors of non fatal MI or mortality at follow-up.. In diabetic patients, PCI with SES implantation neutralizes the excess risk of intimal hyperplasia and decreases occurrence of ISA, but could not modify the propensity of increased adverse clinical outcomes at follow-up.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Diabetes Mellitus, Type 2; Drug-Eluting Stents; Female; Heart Diseases; Humans; Hyperplasia; Kaplan-Meier Estimate; Male; Middle Aged; Myocardial Infarction; Predictive Value of Tests; Proportional Hazards Models; Risk Assessment; Risk Factors; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional

We compared the effect of arterial remodeling on intimal hyperplasia (IH) after the implantation of a sirolimus-eluting stent (SES) and a paclitaxel-eluting stent (PES).. The study population consisted of patients with positive or intermediate remodeling and negative remodeling.. Sixty-nine patients had positive or intermediate remodeling and 107 patients had negative remodeling. At follow-up, late loss was significantly larger (0.58 +/- 0.65 vs. 0.38 +/- 0.55 mm; p = 0.026) in the patients with positive or intermediate remodeling. The IH volume (22.6 +/- 26.2 vs. 12.4 +/- 17.4 mm(3); p = 0.002) and the percent IH (12.9 +/- 14.8 vs. 7.0 +/- 9.6%; p = 0.002) were significantly higher in the patients with positive or intermediate remodeling. Compared to negative remodeling, the IH volume was higher in the PES patients with positive or intermediate remodeling, but this difference was not noted in the SES patients. Multiple-regression analysis revealed that arterial remodeling was a significant independent variable for predicting IH volume in the PES patients (p = 0.018). A positive correlation was found between the remodeling index and the IH volume in the PES patients (r = 0.234, p = 0.028), but not in the SES patients.. This prospective observational intravascular ultrasound study showed that drug-eluting stents may have a different effect on reducing IH accumulation in lesions with preinterventional positive remodeling characteristics which may be related to the different properties of the drug and delivery platform.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Paclitaxel; Regression Analysis; Sirolimus; Tubulin Modulators; Tunica Intima; Ultrasonography, Interventional

The aim of this study was to evaluate the vascular response after everolimus-eluting stent (EES) implantation in the SPIRIT III Japan Registry (JAPAN) compared to EES implantation in the SPIRIT III United States (USA) trial using serial intravascular ultrasound (IVUS) analysis. Data were obtained from the JAPAN and the randomized EES arm of the USA trial. Serial (postprocedure and 8-month follow-up) IVUS analysis was available in 199 lesions (JAPAN 82, USA 117) of 183 patients (JAPAN 73, USA 110). Although no difference was observed in vessel size in the reference segment between the 2 groups, postprocedure minimum lumen area and stent volume index were significantly greater in the JAPAN arm (minimum lumen area 5.8 +/- 2.2 vs 5.1 +/- 1.5 mm(2), p = 0.03; stent volume index 7.0 +/- 2.4 vs 6.3 +/- 1.7 mm(3)/mm, p = 0.03). Postprocedure incomplete stent apposition (ISA) was less frequently observed in the JAPAN arm (15.9% vs 33.3%, p = 0.006), possibly related to higher maximum balloon pressure and/or more postdilatation without excess tissue prolapse or edge dissection. In the JAPAN arm, percent neointimal obstruction and maximum percent cross-sectional narrowing were significantly lower at 8-month follow-up (percent neointimal obstruction 3.5 +/- 4.2% vs 6.8 +/- 6.4%, p = 0.0004). Late acquired ISA was infrequent in the 2 arms. In conclusion, comparative IVUS analysis between the JAPAN and USA arms showed more optimal stent deployment in the JAPAN arm as evidenced by the lower incidence of postprocedure ISA and larger minimum lumen area after the procedure. Moreover, there was less neointimal hyperplasia in patients with EES implants from the JAPAN arm compared to the USA arm.

Topics: Aged; Coronary Artery Disease; Drug-Eluting Stents; Everolimus; Female; Humans; Hyperplasia; Immunosuppressive Agents; Japan; Male; Middle Aged; Randomized Controlled Trials as Topic; Sirolimus; Ultrasonography, Interventional; United States

We investigated the impact of arterial injury on neointimal hyperplasia following implantation of drug-eluting stents (DES).. A total of 196 patients with 223 segments (sirolimus-eluting stents [SES]: 104, paclitaxel-eluting stents [PES]: 119) underwent intravascular ultrasound eight months after DES implantation. Arterial injury was defined as the balloon-to-artery ratio (BAR). Segments were categorised into two groups: high BAR defined as BAR>1.1 (120 segments), and low BAR defined as BAR < or =1.1 (103 segments). Baseline clinical characteristics were similar for both groups. Although reference vessel diameter was smaller, stent diameter, maximal balloon pressure and balloon diameter were higher in the high BAR compared with the low BAR group. Lumen (7.10±1.91 vs. 6.25±1.69, p=0.001), stent (7.31±1.95 vs. 6.41±1.80, p=0.001), and external elastic membrane (17.1±4.9 vs. 14.8±4.0, p<0.0001) areas (mm2) were higher, but neointimal hyperplasia (0.21±0.36 vs. 0.16±0.48, p=0.42) area (mm2) was similar in the high BAR compared with the low BAR group. Arterial injury as assessed by BAR was not associated with the amount of neointimal hyperplasia (R2=0.003, p=0.40).. Arterial injury does not correlate with the amount of neointimal hyperplasia following DES implantation. Conventionally aggressive DES implantation techniques do not adversely affect long-term outcome with respect to restenosis.

Topics: Aged; Angioplasty, Balloon, Coronary; Animals; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Sirolimus; Tunica Intima; Ultrasonography, Interventional

The ZoMaxx I and II trials were randomized controlled studies of the zotarolimus-eluting, phosphorylcholine-coated, TriMaxx stent for the treatment of de novo coronary lesions. The aim of this study was to compare the vessel response between zotarolimus- (ZES) and paclitaxel-eluting stents (PES) using intravascular ultrasound (IVUS).. Data were obtained from the ZoMaxx I and II trials, in which a standard IVUS parameter was available in 263 cases (baseline and 9-months follow up). Neointima-free frame ratio was calculated as the number of frames without IVUS-detectable neointima divided by the total number of frames within the stent. While an increase in vessel and plaque was observed in PES from baseline to follow up, there was no significant change in ZES. At follow up, % neointimal obstruction was significantly higher (15.4 ± 8.8% vs 11.3 ± 9.7%), and minimum lumen area at follow up was significantly smaller in ZES compared to PES. However, the incidence of IVUS-defined restenosis (maximum cross-sectional narrowing >60%) was similar in the 2 groups (3.2% vs 6.7%). Neointima-free frame ratio was significantly lower in ZES. There were 5 cases of late incomplete stent apposition in PES and none in ZES.. These IVUS results demonstrate a similar incidence of severe narrowing between these 2 DES. There was a moderate increase in neointimal hyperplasia that was associated with a greater extent of neointimal coverage in ZES compared with PES.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Chi-Square Distribution; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Multicenter Studies as Topic; Paclitaxel; Prosthesis Design; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

We have shown that the combination of sirolimus and imatinib synergistically inhibits denudation-induced neointimal hyperplasia in rats. We have now dissected the mechanisms behind this synergy and evaluated its long-term efficacy.. After aortic denudation injury, rats received established submaximal doses of sirolimus (1.0 mg/kg/day), imatinib (10.0 mg/kg/day), the combination of these, or vehicle per os from 3 days before the operation until 14 days after injury. Vessel histology and complete blood counts were monitored until 90 days after injury. Neointimal cell outgrowth, migration and proliferation were evaluated in ex vivo vessel cultures. Quantitative real-time polymerase chain reaction and immunohistochemistry were used for gene and protein expression analysis.. The combination therapy caused a synergistic decrease in the number of neointimal nuclei and area throughout the observation period. It also prevented postinjury thrombocytosis and leukocytosis, and almost abolished neointimal cell outgrowth and migration. Furthermore, the combination therapy resulted in upregulation of smooth muscle cell (SMC) markers SM22alpha and cysteine and glycine-rich protein 2, and of the anti-apoptotic BCL2 mRNA.. Combination therapy confers superior long-term vasculoprotection, possibly by inhibition of postoperative thrombocytosis and leukocytosis, inhibition of neointimal cell migration to the injury site and maintenance of cell integrity by inhibition of apoptosis and SMC dedifferentiation.

Topics: Animals; Aorta; Benzamides; Blood Cell Count; Drug Synergism; Hyperplasia; Imatinib Mesylate; LIM Domain Proteins; Male; Microfilament Proteins; Muscle Proteins; Muscle, Smooth, Vascular; Nuclear Proteins; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrimidines; Rats; Rats, Wistar; Sirolimus; Tunica Intima; von Willebrand Factor

Atherosclerosis, restenosis, and posttransplant graft atherosclerosis are characterized by endothelial damage, infiltration of inflammatory cells, and proliferation of smooth muscle cells. The CXCR3-activating chemokines interferon-gamma inducible protein 10 (IP10) and MIG (monokine induced by interferon-gamma) have been implicated in vascular repair and remodeling. The underlying molecular mechanisms, however, remain elusive. Here, we show that wire-mediated arterial injury induced local and systemic expression of IP10 and MIG, resulting in enhanced recruitment of CXCR3(+) leukocytes and hematopoietic progenitor cells. This was accompanied by profound activation of mammalian target of rapamycin complex (mTORC)1, increased reactive oxygen species production, apoptosis, and intimal hyperplasia. Genetic and pharmacological inactivation of CXCR3 signaling not only suppressed recruitment of inflammatory cells but also abolished mTORC1 activation, reduced reactive oxygen species generation, and blocked apoptosis of vascular cells, resulting in significant reduction of intimal hyperplasia in vivo. In vitro, stimulation of T cells with IP10 directly activated mTORC1 and induced generation of reactive oxygen species and apoptosis in an mTORC1-dependent manner. These results strongly indicate that CXCR3-dependent activation of mTORC1 directly links stimulation of the Th1 immune system with the proliferative response of intimal cells in vascular remodeling.

Topics: Animals; Apoptosis; Cardiovascular Agents; Carrier Proteins; Cell Proliferation; Chemokine CXCL10; Chemokine CXCL9; Chemotaxis; Disease Models, Animal; Everolimus; Femoral Artery; Hematopoietic Stem Cells; Humans; Hyperplasia; Inflammation; Jurkat Cells; Mice; Mice, Inbred BALB C; Mice, Knockout; Phosphotransferases (Alcohol Group Acceptor); Reactive Oxygen Species; Receptors, CXCR3; Signal Transduction; Sirolimus; Th1 Cells; Time Factors; TOR Serine-Threonine Kinases

Neointimal hyperplasia is the first step in a cascade leading to a reduced patency rate of saphenous vein grafts in comparison to arterial grafts in coronary artery bypass grafting. Using cultured human saphenous vein grafts as a model for coronary artery bypass grafting, we investigated if the mammalian target of rapamycin inhibitor everolimus attenuates neointimal hyperplasia.. Saphenous vein grafts from 10 patients undergoing coronary artery bypass grafting were processed as follows: from each patient, one segment served as baseline control at day 0. Two segments were cultured in a neointimal hyperplasia model separately. One received no treatment and the other everolimus (1 microM). All vein grafts underwent histomorphometric analysis, assessment of proliferation by Ki-67 immunostaining and quantification of phospho-S6 ribosomal protein using western blot analysis.. Everolimus treatment resulted in reduced neointimal hyperplasia (thickness 3.7+/-1.2 microm) compared to untreated controls (10.1+/-2.5 microm, p=0.008). The intima/intima+media-ratio was reduced in the everolimus group (0.10+/-0.02) compared to untreated controls (0.24+/-0.07, p=0.008). The number of Ki-67 positive proliferating cells in everolimus treated vein grafts (15+/-7 cells/high power field) showed a tendency of reduction compared to untreated controls (36+/-20 cells/high power field, p=0.036). Finally, everolimus treatment resulted in downregulation of S6 ribosomal protein phosphorylation in comparison to untreated controls.. Everolimus is able to reduce neointimal proliferation in cultured human saphenous vein grafts by inhibition of the mammalian target of rapamycin, even though different transfection methods are to be evaluated for a clinical application in coronary artery bypass grafting.

Topics: Blotting, Western; Coronary Artery Bypass; Everolimus; Humans; Hyperplasia; Immunosuppressive Agents; Ki-67 Antigen; Organ Culture Techniques; Ribosomal Protein S6 Kinases; Saphenous Vein; Sirolimus; Tunica Intima; Vascular Patency

Restenosis still occurs, even with the sirolimus-eluting stent (SES), and the precise mechanisms have not yet been elucidated. In the present case, focal in-stent stenosis was discovered on angiography 16 months after SES implantation. Intravascular ultrasound revealed an echolucent homogeneous zone, which has been termed "black hole". A sample of stenotic tissue retrieved by aspiration revealed neointimal hyperplasia, composed of proteoglycans and smooth muscle cells with scanty cellularity. Furthermore, infiltration of many macrophages and T lymphocytes coexisted in the restenotic tissue. These findings suggest that delayed healing is 1 of the mechanisms of SES restenosis.

Topics: Aged; Angioplasty, Balloon, Coronary; Biopsy, Needle; Cardiovascular Agents; Coronary Angiography; Coronary Restenosis; Drug-Eluting Stents; Humans; Hyperplasia; Macrophages; Male; Sirolimus; T-Lymphocytes; Tunica Intima; Ultrasonography, Interventional

Numerical simulations entail modeling assumptions that impact outcomes. Therefore, characterizing, in a probabilistic sense, the relationship between the variability of model selection and the variability of outcomes is important. Under certain assumptions, the stochastic collocation method offers a computationally feasible alternative to traditional Monte Carlo approaches for assessing the impact of model and parameter variability. We propose a framework that combines component shape parameterization with the stochastic collocation method to study the effect of drug depot shape variability on the outcome of drug diffusion simulations in a porcine model. We use realistic geometries segmented from MR images and employ level-set techniques to create two alternative univariate shape parameterizations. We demonstrate that once the underlying stochastic process is characterized, quantification of the introduced variability is quite straightforward and provides an important step in the validation and verification process.

Topics: Algorithms; Anastomosis, Surgical; Animals; Antibiotics, Antineoplastic; Computer Simulation; Finite Element Analysis; Hyperplasia; Models, Animal; Models, Biological; Models, Statistical; Monte Carlo Method; Polytetrafluoroethylene; Prostheses and Implants; Sirolimus; Swine

Long lesions and complex vessel anatomy frequently require the use of overlapping stents to treat a lesion. The purpose of this study was to evaluate the long-term effects of overlapping the Axxess Biolimus A9 eluting stent (BES) with two of the most commonly used, commercially available drug eluting stents. These stents were compared to BxVelocity bare metal (BMS) stents in a porcine coronary stent-injury model.. Nineteen juvenile farm swine, 25-35 kg in weight, 3-6 months in age were utilised. Each animal received an Axxess stent to their coronary artery as permitted by the individual animal's anatomy. A second stent, either a Cypher, sirolimus eluting stent (SES) or, a Taxus, paclitaxel eluting stent (PES), or a BxVelocity bare metal stent (BMS) were implanted in an overlapped fashion. The animals were then followed for either 28 or 180 days as specified by a randomisation scheme. At the end of each follow-up period, they were euthenised, and the vessels containing the overlapping stents were harvested, processed into histological sections, and analysed. Compared to bare metal stents, overlapped segments using DES exhibited delayed vascular healing compared to both the proximal and distal non-overlap sites at each of the follow-up time point. Overall, in the non-overlap stent segments, SES induced significantly more inflammation and neointimal hyperplasia compared to PES and BMS.. In this study of BMS and two different types of DES overlapped with the Axxess Biolimus A9 eluting stent, we found that while there was a delay in the degree of vascular healing with DES compared to BMS, the specific type of DES that was overlapped with BES did not affect the behaviour of the overlap zone in terms of most of the histomorphometric measures at 28 or 180 days. This was true whether the stent was drug eluting or bare metal. More inflammation with delayed healing was seen in the SES compared to PES and BMS.

Topics: Angioplasty, Balloon, Coronary; Animals; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Hyperplasia; Inflammation; Models, Animal; Nickel; Paclitaxel; Platelet Aggregation Inhibitors; Prosthesis Design; Sirolimus; Stents; Swine; Time Factors; Titanium; Wound Healing

Maintaining arterial duct patency by stent implantation may be advantageous in congenital heart disease management algorithms. Rapamycin, an immunosuppressant drug that demonstrates antiproliferative properties and inhibits smooth muscle cell migration, may deter the intimal hyperplasia that occurs during spontaneous closure and after-stent implantation of the arterial duct.. Twenty-eight Yorkshire piglets (7 to 11 days old; weight, 2.2 to 4.9 kg) underwent stent implantation of the arterial duct (rapamycin-eluting (n=14) or bare metal (n=14) stents, 3.5-mm diameter) and were euthanized at 2, 4, and 6 weeks. Dissected arterial ducts were analyzed for lumen diameter, smooth muscle cell, and extracellular matrix components. Isolated arterial duct-derived smooth muscle cells were cultured in the presence or absence of rapamycin. Cellular proliferation rates were assessed by Ki-67 detection and [(3)H]-thymidine incorporation. No significant neointimal proliferation was present in either stent type at 2 weeks. At 4 weeks, the median luminal diameters of the bare metal stents were 87% (P=0.009), 54% (P=0.004), and 77% (P=0.004) that of the drug-eluting stents at the middle and aortic and pulmonary artery ends, respectively. At 6 weeks, the median luminal diameters of the bare metal stents were 0% (P=0.18), 5% (P=0.25), and 61% (P=0.13) that of the drug-eluting stents at the same respective levels. Complete histological occlusion was found in at least 1 level of the lumen in 9 pigs: 1 (17%) in the BMS group at 4 weeks, 5 (83%) in the BMS group at 6 weeks, and 3 (50%) in the DES group at 6 weeks. In vitro studies demonstrated 50%-lower proliferation rates in rapamycin-treated cultures of duct-derived smooth muscle cell cultures (P<0.001).. Rapamycin has antiproliferative actions on the arterial duct. Drug-eluting stents may be a more efficient tool than current palliative options for maintaining patency in critically duct-dependent states, but there may be a finite time-related benefit.

Topics: Animals; Animals, Newborn; Cell Division; Cells, Cultured; Drug-Eluting Stents; Ductus Arteriosus; Elastin; Heart Defects, Congenital; Hyperplasia; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Sirolimus; Sus scrofa; Tunica Intima; Ultrasonography

The aim of this study was to compare efficacy of low- and high-dose sirolimus release (25, 40, or 100 microg) from hydroxyapatite (HAp) with Cypher (Cordis, Johnson & Johnson, Warren, New Jersey) (111 microg sirolimus) in porcine coronary arteries.. Polymer-based sirolimus-eluting stents such as Cypher interfere with vascular healing, probably due to the permanent presence of the polymer coating and the high sirolimus dose. The use of low-dose sirolimus and inert nonpolymeric but biodegradable coatings such as HAp might be more appropriate.. Stents (n = 68) were implanted, guided by quantitative coronary angiography. All swine received clopidogrel and acetylsalicylic acid during 28 days follow-up. Safety of the coating in absence of drugs was studied by comparing HAp with and without a lipid-based release regulating layer (HApR) with bare-metal stents. Efficacy was studied by comparing the release of 25, 40, and 100 microg sirolimus with Cypher.. The safety study (without drug) revealed no differences in neointimal thickening in response to HAp and HApR with complete healing in all groups. Dose response analysis showed that neointimal thickening was similar in all groups regardless of sirolimus dose, with a normal appearance of the endothelium. There was, however, a dose-dependent increase in fibrinoid (p = 0.028), considered to be a marker of delayed healing. The Cypher stent induced the highest amount of fibrinoid.. Reducing the dose of sirolimus eluting from a biocompatible HAp coated stent reduces signs of delayed vascular healing, without affecting neointimal hyperplasia.

Topics: Angioplasty, Balloon, Coronary; Animals; Aspirin; Cardiovascular Agents; Clopidogrel; Coated Materials, Biocompatible; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Durapatite; Hyperplasia; Lipids; Materials Testing; Models, Animal; Platelet Aggregation Inhibitors; Prosthesis Design; Sirolimus; Stainless Steel; Surface Properties; Sus scrofa; Ticlopidine; Wound Healing

We sought to assess changes in antirestenotic efficacy of drug-eluting stents (DES) by restudying subjects at 2 time points after coronary stenting (6 to 8 months and 2 years) and to compare differences in time courses of late luminal loss (LLL) between 3 different DES platforms in use at our institution.. DES therapy is associated with low levels of LLL at 6 to 8 months. The temporal course of neointimal formation after this time point remains unclear.. This prospective, observational, systematic angiographic follow-up study was conducted at 2 centers in Munich, Germany. Patients underwent stenting with permanent-polymer rapamycin-eluting stents (RES), polymer-free RES, or permanent-polymer paclitaxel-eluting stents (PES). The primary end point was delayed LLL (the difference in in-stent LLL between 6 to 8 months and 2 years).. Of 2,588 patients undergoing stenting, 2,030 patients (78.4%) had 6- to 8-month angiographic follow-up and were enrolled in the study. Target lesion revascularization was performed in 259 patients; these patients were not considered for further angiographic analysis. Of 1,771 remaining patients, 1,331 had available 2-year reangiographic data (75.2%). Overall mean (SD) delayed LLL was 0.12 +/- 0.49 mm (0.17 +/- 0.50 mm, 0.01 +/- 0.42 mm, and 0.13 +/- 0.50 mm in permanent-polymer RES, polymer-free RES, and permanent-polymer PES groups, respectively [p < 0.001]). In multivariate analysis, only stent type (in favor of polymer-free RES) predicted delayed LLL.. Ongoing erosion of luminal caliber beyond 6 to 8 months after the index procedure is observed following DES implantation. Absence of permanent polymer from the DES platform seems to militate against this effect.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Restenosis; Drug-Eluting Stents; Female; Germany; Humans; Hyperplasia; Logistic Models; Male; Middle Aged; Paclitaxel; Polymers; Prospective Studies; Prosthesis Design; Risk Assessment; Sirolimus; Time Factors; Treatment Outcome

Topics: Angioplasty, Balloon, Coronary; Animals; Cardiovascular Agents; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Humans; Hyperplasia; Paclitaxel; Polymers; Prosthesis Design; Risk Assessment; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima

Sirolimus was originally used as an immunosuppressant drug but recent reports have indicated that it may have other potential biological effects as an anticancer drug. The chemopreventive efficacy of sirolimus was evaluated in an experimental model of invasive urinary bladder cancer.. ICR mice received N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water for a period of twelve weeks. Sirolimus was administered 5 days a week. Animals were sacrificed either one or four weeks after their final treatment. Ki-67 was immunohistochemically analysed in paraffin-embedded tissue.. No evidence of host toxicity was found. The incidence of BBN-induced invasive urothelial carcinoma was significantly reduced in mice treated with sirolimus. Preneoplastic and neoplastic lesions exhibited a significant decrease in cellular proliferation.. Histopathological and immunohistochemical studies showed that sirolimus reduced tumour incidence and proliferation. Sirolimus should be considered for further in vitro and in vivo studies in order to provide evidence of effectiveness.

Topics: Animals; Antibiotics, Antineoplastic; Butylhydroxybutylnitrosamine; Carcinoma in Situ; Carcinoma, Papillary; Hyperplasia; Immunoenzyme Techniques; Male; Mice; Mice, Inbred ICR; Sirolimus; Urinary Bladder Neoplasms

There is a hypothesis that advanced neointimal stent coverage may protect against stent thrombosis. In the present study, differences in neointimal growth and prevalence of in-stent thrombus between paclitaxel- and sirolimus-eluting stent (PES and SES) were evaluated by optical coherence tomography (OCT).. Follow-up angiographic and OCT examinations at approximately 6 months were performed for 40 patients (20 PES, 20 SES). Late loss was measured by quantitative coronary angiography. Neointimal hyperplasia (NIH) thickness on stent struts was measured by cross-sectional OCT images at 1 mm intervals. After measuring the NIH area in each cross-section, NIH volume was calculated as integral of NIH area within the stent. Late loss, NIH thickness, and NIH volume were greater for PES than for SES (0.42 +/-0.44 vs 0.13 +/-0.12 mm, 118 +/-141 vs 31 +/-39 mum, 53.2 +/-30.5 vs 24.3 +/-14.0 mm(3); P<0.05, respectively). In-stent thrombus was found more frequently in PES than in SES (50 vs 15%; P=0.02).. Although the degree of neointimal growth in PES was generally greater, in-stent thrombus was more common compared with SES. Presence of thrombus in first-generation drug-eluting stents was not related to advanced neointimal growth.

Topics: Adult; Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Stenosis; Coronary Thrombosis; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Platelet Aggregation Inhibitors; Risk Assessment; Risk Factors; Severity of Illness Index; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome; Tunica Intima

Topics: Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Restenosis; Coronary Stenosis; Drug-Eluting Stents; Humans; Hyperplasia; Myocardial Infarction; Prosthesis Design; Sirolimus; Thrombosis; Time Factors; Treatment Outcome

The aim of this study was to explore the determinants of neointimal coverage after sirolimus-eluting stent (SES).. Although SES has significantly reduced in-stent restenosis by inhibiting neointimal hyperplasia, insufficient neointimal coverage after stenting might result in adverse outcomes.. We evaluated 28 SES lesions with both angioscopy and intravascular ultrasound (IVUS). Quantitative assessments of the lesions and stent expansion were performed by IVUS at the time of stent implantation, and degree of neointimal coverage was judged by angioscopy at follow-up (11 +/- 6 months) whether the stent struts were embedded by the neointima ("complete/incomplete" neointimal coverage).. "Complete" coverage was identified in 10 (36%), and "incomplete" coverage was identified in 18 (64%). Time from the stenting to angioscopy as well as the lesion and procedural characteristics were similar between the complete and incomplete coverage groups. The IVUS parameters were also similar, except for the final minimum stent cross-sectional area (CSA) (7.0 +/- 1.8 mm(2) in complete vs. 5.3 +/- 1.9 mm(2) in incomplete, p = 0.02) and lumen CSA at the distal reference site (6.1 +/- 1.4 mm(2) in complete vs. 4.9 +/- 1.2 mm(2) in incomplete, p = 0.02). The ratio of the stent area to the vessel area was significantly larger in the complete coverage than in the incomplete coverage group (0.52 +/- 0.11 vs. 0.39 +/- 0.09, p = 0.002).. Adequate stent sizing relative to the vessel size might contribute to the angioscopically complete neointimal coverage after SES implantation.

Topics: Adult; Aged; Angioplasty, Balloon, Coronary; Angioscopy; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Female; Humans; Hyperplasia; Male; Middle Aged; Prosthesis Design; Retrospective Studies; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Topics: Angioplasty, Balloon, Coronary; Angioscopy; Cardiovascular Agents; Cell Proliferation; Coronary Angiography; Coronary Stenosis; Coronary Vessels; Drug-Eluting Stents; Humans; Hyperplasia; Prosthesis Design; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima; Ultrasonography, Interventional

Recent intravascular ultrasound (IVUS) studies of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) have demonstrated a significant reduction in neointimal hyperplasia (NIH) based on simple coronary lesions. In this study, we evaluated the efficacy of SES and PES using IVUS in complex coronary lesions.. Eighty-seven patients in whom 95 drug-eluting stents (66 SES and 29 PES) were implanted in complex coronary lesions were enrolled in this study. Case selection was based on the availability of IVUS and quantitative coronary angiographic (QCA) examinations at the index procedure and at follow-up. The neointimal volume index (volume/length: NIVI) and percent neointimal volume (% NIV) were calculated. The longitudinal length of stented segments without IVUS-detectable NIH was also evaluated.. The baseline patient demographics were similar between the SES and PES groups. At follow-up, no significant differences were observed in the vessel, plaque, or stent volume indices between the two groups. However, the NIVI and % NIV were significantly lower in the SES group (p<0.01). The longitudinal length of stented segments without IVUS-detectable NIH was significantly higher in the SES group (p<0.01). The net gain was significantly larger in the SES group (2.3+/-0.7 vs. 2.0x0.6 mm, p=0.025), while the rate of major adverse cardiac events was similar between the two groups.. Although SES showed significantly greater suppression of NIH at follow-up, both stents were highly effective at inhibiting NIH in complex coronary lesions.

Topics: Adult; Aged; Coronary Angiography; Coronary Artery Disease; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Sirolimus; Tunica Intima; Ultrasonography, Interventional

Preprocedual C-reactive protein (CRP) has been reported to correlate with in-stent restenosis following bare-metal stent implantation. The aim of this study was to investigate the impact of preprocedural inflammation on neointimal hyperplasia assessed by intravascular ultrasound (IVUS) following everolimus-eluting stent (EES) implantation.. We identified 134 patients meeting the following criteria: 1) patients treated with EES; 2) those with stable or unstable angina; and 3) patients available for high-sensitivity (hs)-CRP before the procedure and volumetric IVUS analysis at follow up. We divided the patients into two groups on the basis of hs-CRP levels (< 3 or > or = 3 mg/L) before the procedure and compared IVUS parameters. Volume index (volume/length) was calculated for vessel (VVI), plaque (PVI), neointima (NIV), stent (SVI), and lumen (LVI). Percent neointimal volume (%NIV) was calculated as (NIV/SVI) x 100. Cross-sectional narrowing (CSN) was defined as neointimal area divided by stent area (%).. There was no significant difference in VVI, PVI, or LVI at either baseline or 8-month follow up between the two groups. At 8-month follow up, there was also no significant difference in %NIV (4.93 +/- 5.66% vs. 4.98 +/- 5.25% p = 0.959) and maximum %CSN (16.81 +/- 13.62% vs. 18.14 +/- 13.91%; p = 0.608) as well as VVI, PVI, and LVI between the two groups. Furthermore, hs-CRP did not correlate with %NIV (r = 0.044; p = 0.610) and maximum %CSN (r = 0.086, p = 0.321) at follow up. There was no significant difference in incidence of late-acquired incomplete stent apposition between the two groups (1.2% vs. 0%; p = 0.512).. Our results suggest that preprocedural inflammation does not affect neointimal hyperplasia following EES implantation.

Topics: Aged; Angina, Unstable; C-Reactive Protein; Drug-Eluting Stents; Everolimus; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Inflammation; Male; Middle Aged; Sirolimus; Tunica Intima; Ultrasonography, Interventional

Growth factor-dependent cell proliferation can cause in-stent neointimal hyperplasia. The study aim was to evaluate whether oral everolimus inhibits the intimal proliferation associated with the implantation of prosthetic pulmonary valved stents.. Prosthetic pulmonary valves were implanted in 12 pigs (mean bodyweight 25 kg) using a transcatheter technique. Tricuspid valves were prepared from a titanium-coated polymer and sewn into a self-expanding nitinol stent (diameter 20 mm). Valved stents were implanted in the pulmonary position, where they remained for three months. In six animals, treatment with 2 mg/kg everolimus (Certican; Novartis) per day was started three days before implantation and continued throughout the course of the experiment. The other six pigs acted as controls. Adjuvant anticoagulation treatment consisted of acetylsalicylic acid and oral clopidogrel. After three months, hemodynamic valve function was investigated at catheterization and with MRI. At postmortem investigation the valved stents were explanted and subjected to macroscopic, histological and electron microscopic examination.. There were no adverse side effects due to everolimus treatment. The overall mean everolimus plasma level during the study was 4.2 +/- 2.4 ng/ml. MRI revealed intact valve function with a regurgitation fraction of 7.3 +/- 4.2% in controls and 4.3 +/- 3.1% in the everolimus group (p <0.01). On macroscopic inspection and histological examination, the everolimus group showed only a thin tissue coverage of the stent struts. The valve cusps were free from intimal thickening, and electron microscopy showed a thin continuous cellular coating. In contrast, substantial neointimal formation was noted in controls. Tissue neogenesis was pronounced at the base of the valve, extended to the valve cusps, and caused valve thickening and foreshortening.. The oral administration of everolimus effectively inhibits tissue neogenesis in pulmonary valved stents in pigs.

Topics: Animals; Cell Proliferation; Everolimus; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Hemodynamics; Hyperplasia; Immunosuppressive Agents; Microscopy, Electron, Scanning; Pulmonary Valve; Sirolimus; Stents; Swine; Tunica Intima

Despite the use of the sirolimus (rapamycin) drug-eluting coronary stent, diabetics are at increased risk of developing in-stent restenosis for unclear reasons. Hyperleptinemia, which often coexists with diabetes and metabolic syndrome, is an independent risk factor for progression of coronary artery disease. It has not been determined whether elevated circulating leptin decreases the efficacy of the sirolimus drug-eluting stent in inhibiting neointimal hyperplasia, the process underlying restenosis after stenting. Here we show that leptin activates the mammalian target of rapamycin (mTOR) signaling pathway in primary murine vascular smooth muscle cells (VSMC) and stimulates VSMC proliferation in a PI3K-dependent fashion. Exogenous leptin, administered at levels comparable to those found in obese humans, promotes neointimal VSMC hyperplasia in a murine femoral artery wire injury model. Leptin significantly increases the dose of the mTOR inhibitor sirolimus that is required for effective inhibition of neointimal formation. Combination therapy with LY294002, a PI3K inhibitor, and sirolimus effectively inhibits leptin-enhanced neointimal hyperplasia. These data show that, in the setting of hyperleptinemia, higher doses of an mTOR inhibitor, or combination therapy with mTOR and PI3K inhibitors, inhibits neointimal hyperplasia after arterial injury. These studies may explain the higher rates of restenosis observed in diabetics treated with a sirolimus-eluting coronary stent and suggest a potential novel therapeutic approach for inhibiting in-stent restenosis in such patients.

Topics: Animals; Antibiotics, Antineoplastic; Cells, Cultured; Female; Humans; Hyperplasia; Leptin; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Receptors, Leptin; Signal Transduction; Sirolimus; Stents; TOR Serine-Threonine Kinases; Tunica Intima

It recently has been hypothesized that a larger late loss may have a protective role against stent thrombosis. The relationship between angiographic late loss and the presence of thrombus based on angioscopic findings within paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) was investigated in this study.. Prospective 6-month follow-up angiographic and angioscopic examinations were performed on 18 patients for PES and on 20 patients for SES. Late loss was measured by quantitative coronary angiography. Angioscopic neointimal stent coverage (NSC) grade was classified as follows: 0=uncovered struts without neointima, 1=visible struts through thin neointima, and 2=no visible struts. In each patient, maximum NSC, minimum NSC, and the existence of thrombus were evaluated. Late loss and maximum NSC were greater in PES than in SES (0.38+/-0.43 versus 0.10+/-0.23 mm; P=0.02 and P=0.0004, respectively). Late loss was correlated with maximum NSC (grade 0, 0.06+/-0.01 mm; grade 1, 0.10+/-0.05 mm; and grade 2, 0.48+/-0.46 mm), whereas there was no correlation between late loss and minimum NSC. The prevalence of patients with uncovered struts did not differ (44% of PES, 40% of SES; P=0.78). In-stent thrombus was found more frequently in PES than in SES (72% versus 40%, P=0.046) despite no occurrence of stent thrombosis. Only within PES were thrombi found in the segments of NSC grade 2 associated with large late loss.. The present study suggests that angiographic large late loss was not associated with a low risk of in-stent thrombus.

Topics: Aged; Angioscopy; Blood Vessel Prosthesis Implantation; Coronary Angiography; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Paclitaxel; Sirolimus

A significant fraction of vascular smooth muscle cells (VSMCs) undergo rapid apoptosis after balloon angioplasty. In this study, we tested the hypothesis that protecting VSMCs from undergoing apoptosis prevents the cascade of events that lead to intimal hyperplasia.. Rapamycin-loaded gel-like nanoparticles (mean diameter, 54+/-5 nm) were infused locally in a rat carotid artery model of vascular injury. The drug has both antiapoptotic and antiproliferative effects on VSMCs and hence was selected for the current study. Localized delivery of nanoparticles sustained the drug level in the target artery for >2 weeks; demonstrated significant inhibition of hyperplasia (intima/media ratio, 1.5+/-0.02 versus 2.7+/-0.6; P<0.01); and most importantly, re-endothelialized the injured artery (endothelium coverage: treated 82% versus control 28%). We also demonstrated inhibition of activation of caspase-3/7 enzymes in the treated artery, preventing VSMCs from undergoing apoptosis and subsequent infiltration of macrophages.. It may be postulated that the localized delivery of rapamycin inhibited apoptosis of VSMCs, minimizing the inflammatory response to the injury and, thus, creating conditions conducive to vascular repair (re-endothelialization). Unlike stenting, which can lead to thrombosis and increased risk for in-stent restenosis, our approach could eliminate or minimize long-term complications because the injured artery undergoes a natural process of re-endothelialization.

Topics: Animals; Apoptosis; Cardiovascular Agents; Carotid Arteries; Caspase Inhibitors; Cells, Cultured; Endothelium, Vascular; Hyperplasia; Immunohistochemistry; In Situ Nick-End Labeling; Macrophages; Male; Muscle, Smooth, Vascular; Nanoparticles; Rats; Rats, Sprague-Dawley; Sirolimus; Tunica Intima

This study evaluated the inflammatory reaction at the site of overlapping drug-eluting stents (DES) in a porcine model of in-stent restenosis.. Twenty bare metal stents (BMS) (group I; n=10), 20 sirolimus-eluting stents (SES) (group II: n=10), 20 paclitaxel-eluting stent (PES) (group III: n=10), and 10 PES and 10 SES (group IV: n=10) were overlapped in the left anterior descending coronary arteries of 40 pigs. Follow-up coronary angiography and histopathology were performed at 4 weeks after stenting. For the overlapped segments, the minimal luminal diameter at 4 weeks was smaller in group I than in the other groups (1.78+/-0.13 mm, 2.79+/-0.09 mm, 2.90+/-0.04 mm, 2.80+/-0.07 mm, respectively; p<0.001), and the neointimal area (5.51+/-0.58 mm2, 2.38+/-0.53 mm2, 2.07+/-0.37 mm2, 2.39+/-0.58 mm2, respectively; p<0.001) and area stenosis (68.74+/-4.02%, 27.79+/-4.73%, 23.66+/-3.24%, 27.63+/-4.07%, respectively; p<0.001) were higher in group I than in the other groups; however, the inflammatory score was higher in group III than in the other groups (1.80+/-0.42, 2.10+/-0.32, 2.90+/-0.31, 2.50+/-0.52, respectively; p<0.001) and the endothelization score was lower in group III than in the other groups (2.80+/-0.42, 2.30+/-0.67, 1.30+/-0.48, 2.10+/-0.74, respectively; p<0.001).. Compared with BMS, DES inhibit neointimal hyperplasia, but inflammation and poor endothelization occur at the site of overlapping stents.

Topics: Animals; Cell Proliferation; Coronary Restenosis; Coronary Stenosis; Coronary Vessels; Disease Models, Animal; Drug-Eluting Stents; Endothelium, Vascular; Female; Hyperplasia; Inflammation; Paclitaxel; Sirolimus; Stents; Swine; Tunica Intima

Cardiac allograft vasculopathy (CAV) is a major cause of death after heart transplantation (HT). The reduced bioavailability of endothelium-derived nitric oxide may play a role in endothelial vasodilator dysfunction and thus in the structural changes characterizing CAV. A potential contributor to endothelial pathobiology is asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor. It was hypothesized that ADMA concentrations may influence CAV progression during the first postoperative year.. Thirty-two consecutive HT recipients underwent intravascular ultrasound evaluation at month 1 and year 1 after HT. Immunosuppression included mycophenolate mofetil (MMF, n=16) and sirolimus (n=16). Change in intimal volume greater than the median and vascular remodeling were major outcome measures.. Plasma ADMA levels were associated with subsequent development of intimal hyperplasia (risk ratio [95% confidence interval] =2.72 [1.06-6.94]; P=0.038), and plasma ADMA levels greater than 0.70 micromol/L most accurately identified patients who would have developed intimal hyperplasia. However, ADMA levels did not correlate with negative coronary remodeling. Treatment with sirolimus, as compared with MMF, was associated with significantly lower ADMA levels (0.65+/-0.12 vs. 0.77+/-0.10 micromol/L; P<0.01) and less intimal hyperplasia (risk ratio [95% confidence interval] = 0.08 [0.01-0.56]; P=0.01).. Elevated plasma ADMA is associated with coronary intimal hyperplasia, supporting the importance of nitric oxide synthase inhibition in CAV pathogenesis. Treatment with sirolimus (rather than MMF) is associated with lower ADMA levels and reduced risk of accelerated CAV.

Topics: Adult; Aged; Arginine; Biomarkers; Heart Transplantation; Humans; Hyperplasia; Immunosuppressive Agents; Longitudinal Studies; Middle Aged; Sirolimus; Transplantation, Homologous; Tunica Intima; Ultrasonography; Vascular Diseases

To investigate the efficacy of the malononitrilamide FK778 to prevent vascular smooth muscle cell (SMC) migration/proliferation, and vascular fibrosis, the key events in restenosis development using in vivo and in vitro studies.. Since the high rate of restenosis after percutaneous transluminal coronary angioplasty limited its long-term success, the implementation of locally delivered antiproliferative/immunosuppressive agents became advantageous.. Rats underwent balloon denudation of the abdominal aorta and received sirolimus, tacrolimus, or FK778 for 28 days in varying doses. Aortas were harvested for histologic evaluation, profibrotic gene expression, and organ chamber studies. Antifibrotic, antiproliferative and antimigratory effects of the immunosuppressants were further evaluated in vitro.. Histology of untreated animals revealed marked intimal hyperplasia with moderate luminal obliteration. Neointima formation was dose-dependently attenuated by all three agents with FK778 and sirolimus being most efficacious. Organ chamber relaxation studies showed a leftward shift of the nitroglycerin and the acetylcholine dose-responses in all treatment groups, indicating diminished endothelial dysfunction. In vivo, only FK778 treatment revealed a significant downregulation of the TGF-beta/vasorin system which could be explained by upregulation of the TGF-beta-inhibitory mediator SMAD7. In vitro, FK778 showed most potent antiproliferative and antimigratory effects on SMC compared with sirolimus and tacrolimus. Only the antiproliferative effect of FK778 was due to pyrimidine synthesis blockade and could be reversed by uridine supplementation.. The malononitrilamide FK778 proved highly efficacious against restenosis development by targeting two major components of intimal hyperplasia: SMC proliferation/migration and vascular fibrosis. Thus, the introduction of malononitrilamide-loaded stents may be a promising effort for future strategies.

Topics: Alkynes; Animals; Aorta, Abdominal; Carrier Proteins; Cell Movement; Cell Proliferation; Endothelium, Vascular; Graft Occlusion, Vascular; Hyperplasia; Immunosuppressive Agents; Isoxazoles; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nitriles; Rats; Rats, Inbred Lew; RNA, Messenger; Sirolimus; Smad7 Protein; Tacrolimus; Transforming Growth Factor beta1; Tunica Intima; Vasodilation; Vasodilator Agents

Recently, reports of stent fracture with focal restenosis have suggested that it is another mechanism of in-stent restenosis after implantation of sirolimus-eluting stents. However, the mechanism by which strut disruption occurs remains unknown. Current reports of in-stent restenosis suggest that fracture of drug-eluting stents is different from bare-metal stents, and can progress to restenosis and reocclusion. We report on a patient with a fractured stent in a patent coronary artery that progressed to diffuse neointimal hyperplasia presenting with acute myocardial infarction 2 years after stent placement.

Topics: Coronary Angiography; Coronary Artery Disease; Disease Progression; Drug Delivery Systems; Equipment Failure; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Myocardial Infarction; Sirolimus; Stents; Treatment Failure; Tunica Intima

Late stent thrombosis (LST) after Cypher and Taxus drug-eluting stent placement has emerged as a major concern. Although the clinical predictors of LST have been reported, specific morphological and histological correlates of LST remain unknown.. From a registry totaling 81 human autopsies of drug-eluting stents, 46 (62 lesions) had a drug-eluting stent implanted >30 days. We identified 28 lesions with thrombus and compared those with 34 of similar duration without thrombosis using computer-guided morphometric and histological analyses. LST was defined as an acute thrombus within a coronary artery stent in place >30 days. Multiple logistic generalized estimating equations modeling demonstrated that endothelialization was the best predictor of thrombosis. The morphometric parameter that best correlated with endothelialization was the ratio of uncovered to total stent struts per section. A univariable logistic generalized estimating equations model of occurrence of thrombus in a stent section versus ratio of uncovered to total stent struts per section demonstrated a marked increase in risk for LST as the number of uncovered struts increased. The odds ratio for thrombus in a stent with a ratio of uncovered to total stent struts per section >30% is 9.0 (95% CI, 3.5 to 22).. The most powerful histological predictor of stent thrombosis was endothelial coverage. The best morphometric predictor of LST was the ratio of uncovered to total stent struts. Heterogeneity of healing is a common finding in drug-eluting stents with evidence of LST and demonstrates the importance of incomplete healing of the stented segment in the pathophysiology of LST.

Topics: Aged; Angioplasty, Balloon, Coronary; Anthropometry; Aspirin; Clopidogrel; Coronary Restenosis; Coronary Thrombosis; Death, Sudden, Cardiac; Drug Implants; Drug Utilization; Endothelium, Vascular; Equipment Design; Equipment Failure; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Myocardial Infarction; Odds Ratio; Paclitaxel; Platelet Aggregation Inhibitors; Sirolimus; Stents; Ticlopidine; Tunica Intima; Wound Healing

Topics: Angioplasty, Balloon, Coronary; Clinical Trials as Topic; Contrast Media; Coronary Aneurysm; Coronary Thrombosis; Drug Implants; Equipment Failure; Follow-Up Studies; Humans; Hyperplasia; Multicenter Studies as Topic; Paclitaxel; Sirolimus; Sodium Chloride; Stents; Tunica Intima; Ultrasonography, Interventional

Stent thrombosis may occur late after drug-eluting stent (DES) implantation, and its cause remains unknown. The present study investigated differences of the stented segment between patients with and without very late stent thrombosis with the use of intravascular ultrasound.. Since January 2004, patients presenting with very late stent thrombosis (> 1 year) after DES implantation underwent intravascular ultrasound. Findings in patients with very late stent thrombosis were compared with intravascular ultrasound routinely obtained 8 months after DES implantation in 144 control patients, who did not experience stent thrombosis for > or = 2 years. Very late stent thrombosis was encountered in 13 patients at a mean of 630+/-166 days after DES implantation. Compared with DES controls, patients with very late stent thrombosis had longer lesions (23.9+/-16.0 versus 13.3+/-7.9 mm; P<0.001) and stents (34.6+/-22.4 versus 18.6+/-9.5 mm; P<0.001), more stents per lesion (1.6+/-0.9 versus 1.1+/-0.4; P<0.001), and stent overlap (39% versus 8%; P<0.001). Vessel cross-sectional area was similar for the reference segment (cross-sectional area of the external elastic membrane: 18.9+/-6.9 versus 20.4+/-7.2 mm2; P=0.46) but significantly larger for the in-stent segment (28.6+/-11.9 versus 20.1+/-6.7 mm2; P=0.03) in very late stent thrombosis patients compared with DES controls. Incomplete stent apposition was more frequent (77% versus 12%; P<0.001) and maximal incomplete stent apposition area was larger (8.3+/-7.5 versus 4.0+/-3.8 mm2; P=0.03) in patients with very late stent thrombosis compared with controls.. Incomplete stent apposition is highly prevalent in patients with very late stent thrombosis after DES implantation, suggesting a role in the pathogenesis of this adverse event.

Topics: Aged; Angioplasty, Balloon, Coronary; Anthropometry; Coronary Angiography; Coronary Thrombosis; Coronary Vessels; Drug Implants; Equipment Failure; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Multicenter Studies as Topic; Paclitaxel; Randomized Controlled Trials as Topic; Sirolimus; Stents; Time Factors; Tunica Intima; Ultrasonography, Interventional

Topics: Coronary Angiography; Coronary Restenosis; Coronary Vessels; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Stents; Tomography, Optical Coherence; Tunica Intima

Observational clinical studies have shown that patients with diabetes have less favorable results after percutaneous coronary intervention compared with the non-diabetic counterparts, but its mechanism remains unclear. The aim of this study was to examine the changes of neointimal hyperplasia after sirolimus-eluting stent (SES) implantation in a diabetic porcine model, and to evaluate the impact of aortic inflammation on this proliferative process.. Diabetic porcine model was created with an intravenous administration of a single dose of streptozotocin in 15 Chinese Guizhou minipigs (diabetic group); each of them received 2 SES (Firebird, Microport Co, China) implanted into 2 separated major epicardial coronary arteries. Fifteen non-diabetic minipigs with SES implantation served as controls (control group). At 6 months, the degree of neointimal hyperplasia was determined by repeat coronary angiography, intravascular ultrasound (IVUS) and histological examination. Tumor necrosis factor (TNF)-alpha protein level in the aortic intima was evaluated by Western blotting, and TNF-alpha, interleukin (IL)-1beta and IL-6 mRNA levels were assayed by reverse transcription and polymerase chain reaction.. The distribution of stented vessels, diameter of reference vessels, and post-procedural minimal lumen diameter were comparable between the two groups. At 6-month follow-up, the degree of in-stent restenosis (40.4 +/- 24.0% vs. 20.2 +/- 17.7%, p < 0.05), late lumen loss (0.33 +/- 0.19 mm vs. 0.10 +/- 0.09 mm, p < 0.001) by quantitative angiography, percentage of intimal hyperplasia in the stented area (26.7 +/- 19.2% vs. 7.3 +/- 6.1%, p < 0.001) by IVUS, and neointimal area (1.59 +/- 0.76 mm2 vs. 0.41 +/- 0.18 mm2, p < 0.05) by histological examination were significantly exacerbated in the diabetic group than those in the controls. Significant increases in TNF-alpha protein and TNF-alpha, IL-1beta and IL-6 mRNA levels were observed in aortic intima in the diabetic group.. Neointimal hyperplasia persisted at least up to 6 months after SES implantation in diabetic porcine, which may be partly related to an exaggerated inflammatory response within the blood vessel wall. Our results provide theoretical support for potential direct beneficial effects of anti-diabetic and anti-inflammation medications in reducing the risk of restenosis after stenting.

Topics: Animals; Catheters, Indwelling; Coronary Vessels; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Disease Models, Animal; Hyperplasia; Male; Sirolimus; Stents; Swine; Tunica Intima

Stenosis at a vascular anastomotic site has been a significant clinical issue. We tested the hypothesis that rapamycin-eluting biodegradable poly L-lactic acid and epsilon-caprolactone copolymer (PLA-CL) film applied externally can inhibit neointimal hyperplasia in a canine vascular anastomosis model.. Femoral artery graft interposition was performed in 25 beagles. Beagles were divided into five groups (five in each): graft interposition without PLA-CL film (control); with PLA-CL film only; and PLA-CL containing rapamycin 8 microg, 80 microg, and 800 microg. Orthotopic arterial graft interposition was performed on the left side and vein graft from the ipsilateral femoral vein was interposed on the right. Morphometric and immunochemical analyses were performed at four-week intervals.. In arterial graft models, the ratio of intimal area (intimal area divided by the entire vessel area) was significantly reduced in all the three rapamycin-eluting film groups compared with control (0.19, 0.07, 0.05, and 0.38 in 8 microg, 80 microg, 800 microg groups and control, respectively, p < 0.05). In vein graft models, the ratio of intimal area was significantly decreased only in the 800 microg rapamycin group compared with control (0.33 vs 0.54, p < 0.05). Inhibition of neointimal growth was associated with reduced cell proliferation, as evidenced by proliferating cell nuclear antigen immunostaining and diminished alpha-actin positive vascular smooth muscle cells.. Rapamycin-eluting biodegradable PLA-CL film applied externally can inhibit neointimal hyperplasia of arterial and vein grafts in a canine model. The inhibitory effect of rapamycin-eluting film against neointimal growth is more pronounced in the arterial graft than the vein graft.

Topics: Anastomosis, Surgical; Animals; Biofilms; Disease Models, Animal; Dogs; Femoral Artery; Hyperplasia; Sirolimus; Tunica Intima; Vascular Surgical Procedures

Interferon (IFN)-gamma, a cytokine characteristically expressed in arteriosclerotic diseases, acts directly on vascular smooth muscle cells to induce cellular proliferation and intimal expansion. Signaling by the mammalian target of rapamycin raptor complex, known as mTORC1, is associated with cell growth and is active within arteriosclerotic lesions but is not known to be triggered by proinflammatory factors in vascular smooth muscle cells. We investigated the mechanisms for the proarteriosclerotic effects of IFN-gamma in the absence of leukocytes by exploiting the species specificity of this cytokine in a chimeric model of immunodeficient mouse recipients bearing human coronary artery grafts and intravenously inoculated with adenovirus encoding a human IFN-gamma transgene. We found that IFN-gamma-mediated vascular smooth muscle cell proliferation and intimal expansion were associated with phosphorylation of the mTORC1 effector ribosomal protein S6 kinase 1, that the graft morphological changes and S6 kinase 1 activation were inhibited by the mTORC1 inhibitor rapamycin in vivo, and that IFN-gamma-induced mTORC1 signaling was dependent on phosphatidylinositol 3-kinase activity under serum-free conditions in vitro. Our work establishes an immunologic stimulus for mTORC1 signaling in vascular smooth muscle cells, emphasizes that mTORC1 activation is critical in immune-mediated vascular remodeling, and provides further mechanistic insight into the successful clinical application of rapamycin therapy for atherosclerosis and graft arteriosclerosis.

Topics: Adaptor Proteins, Signal Transducing; Adenoviridae; Animals; Aorta; Cell Proliferation; Cells, Cultured; Chromones; Coronary Artery Disease; Coronary Vessels; Enzyme Inhibitors; Gene Transfer Techniques; Genetic Vectors; Graft Rejection; Humans; Hyperplasia; Immunosuppressive Agents; Interferon-gamma; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, SCID; Morpholines; Multiprotein Complexes; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proteins; Regulatory-Associated Protein of mTOR; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Time Factors; Tissue Culture Techniques; TOR Serine-Threonine Kinases; Transcription Factors; Transplantation, Heterologous; Tunica Intima

Amplification of the HER2 (ErbB2, c-Neu) proto-oncogene in breast cancer is associated with poor prognosis and high relapse rates. HER2/ErbB2, in conjunction with ErbB3, signals through the Akt/phosphatidylinositol 3-kinase pathway and leads to the activation of mammalian target of rapamycin (mTOR), a critical mRNA translation regulator that controls cell growth. Gene expression analysis of mammary tumors collected from mouse mammary tumor virus-c-Neu transgenic mice revealed that mRNA levels of several mTOR pathway members were either up-regulated (p85/phosphatidylinositol 3-kinase and p70S6 kinase) or down-regulated (eIF-4E-BP1) in a manner expected to enhance signaling through this pathway. Treatment of these mice with the mTOR inhibitor rapamycin caused growth arrest and regression of primary tumors with no evidence of weight loss or generalized toxicity. The treatment effects were due to decreased proliferation, associated with reduced cyclin D1 expression, and increased cell death in primary tumors. Whereas many of the dead epithelial cells had the histopathologic characteristics of ischemic necrosis, rapamycin treatment was not associated with changes in microvascular density or apoptosis. Rapamycin also inhibited cellular proliferation in lung metastases. In summary, data from this preclinical model of ErbB2/Neu-induced breast cancer show that inhibition of the mTOR pathway with rapamycin blocks multiple stages of ErbB2/Neu-induced tumorigenic progression.

Topics: Animals; Antibiotics, Antineoplastic; Cell Death; Cell Proliferation; Endothelial Cells; Enzyme Activation; Epithelium; Hyperplasia; Lung Neoplasms; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Transgenic; Protein Kinases; Rats; Receptor, ErbB-2; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Adaptor Proteins, Signal Transducing; Adenoviridae; Animals; Cell Proliferation; Chromones; Coronary Artery Disease; Coronary Vessels; Enzyme Inhibitors; Gene Transfer Techniques; Graft Rejection; Humans; Hyperplasia; Immunosuppressive Agents; Interferon-gamma; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, SCID; Morpholines; Multiprotein Complexes; Muscle, Smooth, Vascular; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proteins; Regulatory-Associated Protein of mTOR; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Transcription Factors; Transplantation, Heterologous; Tunica Intima

The phenotypic plasticity of mature vascular smooth muscle cells (VSMCs) facilitates angiogenesis and wound healing, but VSCM dedifferentiation also contributes to vascular pathologies such as intimal hyperplasia. Insulin/insulin-like growth factor I (IGF-I) is unique among growth factors in promoting VSMC differentiation via preferential activation of phosphatidylinositol 3-kinase (PI3K) and Akt. We have previously reported that rapamycin promotes VSMC differentiation by inhibiting the mammalian target of rapamycin (mTOR) target S6K1. Here, we show that rapamycin activates Akt and induces contractile protein expression in human VSMC in an insulin-like growth factor I-dependent manner, by relieving S6K1-dependent negative regulation of insulin receptor substrate-1 (IRS-1). In skeletal muscle and adipocytes, rapamycin relieves mTOR/S6K1-dependent inhibitory phosphorylation of IRS-1, thus preventing IRS-1 degradation and enhancing PI3K activation. We report that this mechanism is functional in VSMCs and crucial for rapamycin-induced differentiation. Rapamycin inhibits S6K1-dependent IRS-1 serine phosphorylation, increases IRS-1 protein levels, and promotes association of tyrosine-phosphorylated IRS-1 with PI3K. A rapamycin-resistant S6K1 mutant prevents rapamycin-induced Akt activation and VSMC differentiation. Notably, we find that rapamycin selectively activates only the Akt2 isoform and that Akt2, but not Akt1, is sufficient to induce contractile protein expression. Akt2 is required for rapamycin-induced VSMC differentiation, whereas Akt1 appears to oppose contractile protein expression. The anti-restenotic effect of rapamycin in patients may be attributable to this unique pattern of PI3K effector regulation wherein anti-differentiation signals from S6K1 are inhibited, but pro-differentiation Akt2 activity is promoted through an IRS-1 feedback signaling mechanism.

Topics: Antibiotics, Antineoplastic; Cell Differentiation; Elafin; Enzyme Activation; Humans; Hyperplasia; Insulin Receptor Substrate Proteins; Isoenzymes; Muscle Proteins; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Phosphoproteins; Phosphorylation; Protein Kinases; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tunica Intima; Wound Healing

C-reactive protein (CRP) is an inflammatory marker that predicts cardiac events in patients with coronary syndromes. However, data on the relationship between the CRP level and in-stent restenosis are contradictory. The objective of this study was to investigate the relationship between the basal CRP level and the neointimal hyperplasia volume measured by intracoronary ultrasound 4 months after implantation of a zotarolimus-eluting stent.. The study included 40 consecutive patients who underwent zotarolimus-eluting stent implantation. Patients were divided into quartiles according to their preprocedural CRP level. Intracoronary ultrasound was performed after stent implantation and at 4 months, and the neointimal hyperplasia volume was determined using Simpson's rule. Correlation and linear regression analyses were used to evaluate the relationships between variables. Multivariate analysis was used to identify variables that were independently related to neointimal hyperplasia volume.. The patients' mean age was 58 (8) years, 55% were male, and 40% had diabetes mellitus. There was no difference in baseline characteristics between the quartiles. The hyperplasia volumes were 4.8 (4.2) microl and 15.8 (10.0) microl in the first and fourth quartiles, respectively (P< .001). There was a significant positive correlation between the CRP level and neointimal hyperplasia volume (r = 0.64, P=.0001). The CRP level, the postimplantation lumen volume, and the final deployment pressure were all independent predictors of neointimal hyperplasia.. In this study, an independent correlation was observed between the CRP level before zotarolimus-eluting stent implantation and the neointimal hyperplasia volume at 4-month follow-up.

Topics: C-Reactive Protein; Coronary Vessels; Drug Delivery Systems; Female; Humans; Hyperplasia; Imaging, Three-Dimensional; Male; Middle Aged; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

The aim of this study was to examine the anti-inflammatory effect of abciximab-coated stent in a porcine coronary overstretch restenosis model. Ten abciximab-coated stents, ten sirolimus-eluting stents (SES), and ten paclitaxel-eluting stents (PES) were deployed with oversizing (stent/artery ratio 1.3:1) in porcine coronary arteries, and histopathologic analysis was done at 28 days after stenting. There were no significant differences in the neointima area normalized to injury score and inflammation score among the three stent groups (1.58 +/- 0.43 mm(2), 1.57 +/-0.39 mm(2) in abciximab-coated stent group vs. 1.69 +/- 0.57 mm(2), 1.72 +/- 0.49 mm(2) in the SES group vs. 1.92 +/- 0.86 mm(2), 1.79 +/- 0.87 mm(2) in the PES group, respectively). In the neointima, most inflammatory cells were lymphohistiocytes. Significant positive correlations were found between the extent of inflammatory reaction and the neointima area (r=0.567, p<0.001) and percent area stenosis (r=0.587, p<0.001). Significant correlations were found between the injury score and neointimal area (r=0.645, p<0.001), between the injury score and the inflammation score (r=0.837, p<0.001), and between the inflammation score and neointimal area (r=0.536, p=0.001). There was no significant difference in the inflammatory cell counts normalized to injury score among the three stent groups (75.5 +/- 23.1/microL in abciximabcoated stent group vs. 78.8 +/- 33.2/microL in the SES group vs. 130.3 +/- 46.9/microL in the PES group). Abciximab-coated stent showed comparable inhibition of inflammatory cell infiltration and neointimal hyperplasia with other drug-eluting stents in a porcine coronary restenosis model.

Topics: Abciximab; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Antibodies, Monoclonal; Arteries; Constriction, Pathologic; Coronary Restenosis; Disease Models, Animal; Drug-Eluting Stents; Female; Hyperplasia; Immunoglobulin Fab Fragments; Inflammation; Paclitaxel; Sirolimus; Swine; Tunica Intima

Accelerated arteriosclerosis remains a major limitation to therapeutic interventions such as angioplasty, stent deployment, and solid organ transplantation. Rapamycin, a powerful new immunosuppressant set to replace calcineurin inhibitors in the transplant setting, and imatinib mesylate, a receptor tyrosine kinase inhibitor, are both angioprotective. Here, we explored the pharmacological and therapeutic interactions of these two agents in a rat model of neointimal hyperplasia.. Wistar rats, subjected to balloon catheter-induced aortic injury, received daily drug treatment until postoperative day 14 and were subsequently sacrificed or followed up to day 40 without further treatment. Development of neointimal lesions was assessed histologically and immunohistochemically. Steady-state rapamycin levels in whole blood were determined by HPLC-UV.. Rapamycin and imatinib, administered individually or in combination, produced no signs of overt toxicity. Continuous postoperative therapy with either rapamycin (0.5-1.5 mg/kg/day) or imatinib (2- 50 mg/kg/day) dose-dependently suppressed neointimal hyperplasia on day 14. Combined treatment (0.5 or 1 + 10 mg/kg/day, respectively) showed a trend towards synergistic action on day 14. Withdrawal of medication on day 14 nullified the early therapeutic effect of either agent by day 40. In contrast, early combination therapy (1 + 10 mg/kg/day) achieved long-term suppression of neointimal hyperplasia by approximately 81%. Notably, coadministration of imatinib appeared to reduce exposure to rapamycin, although this finding did not reach statistical significance.. Short-term combination therapy with rapamycin and imatinib is well tolerated and produces synergistic, sustained suppression of neointimal hyperplasia in rats. Subject to clinical evaluation, this new drug regimen may afford definitive prophylaxis against accelerated arteriosclerosis.

Topics: Angioplasty, Balloon; Animals; Aorta, Abdominal; Arteriosclerosis; Benzamides; Drug Synergism; Hyperplasia; Imatinib Mesylate; Male; Piperazines; Protein-Tyrosine Kinases; Pyrimidines; Rats; Rats, Wistar; Sirolimus

The addition of drug elution to coronary stents plays an integral role in coronary restenosis prevention. The present study was undertaken to determine the mechanism of action and the in vitro and in vivo efficacy of zotarolimus, a new chemical entity designed specifically for elution from phosphorylcholine (PC)-coated stents, for the reduction of neointimal hyperplasia in porcine coronary arteries.. In vitro studies of Zotarolimus bound to FKBP-12 potently inhibited smooth muscle cells (SMCs) and endothelial cell (EC) proliferation. Twenty PC-only and 20 stents eluting zotarolimus 10 microg/mm were implanted in the coronary arteries of 20 domestic juvenile swine. After 28 days, zotarolimus stents exhibited less area stenosis (22.4+/-8.6 vs. 35.7+/-13%, P = 0.01), less neointimal area (1.69+/-0.55 vs. 2.78+/-1.07 mm(2), P = 0.01), less neointimal thickness (0.25+/-0.07 vs. 0.38+/-0.13 mm, P = 0.01), and greater lumen area (6.07+/-1.39 vs. 5.02+/-1.3 mm2, P = 0.01). All arteries in both the polymer-only and polymer/drug stent showed near-complete healing and minimal toxicity. Zotarolimus did not affect the extrastent segments nor alter the overall artery size (external elastic lamina cross-sectional area 9.18+/-1.19 vs. 9.06+/-1.28 mm2, P = 0.7).. Zotarolimus binds to FKBP-12 and in vitro inhibits SMC and EC proliferation. Zotarolimus applied to PC-coated stents reduces neointima in the swine coronary model after 28 days. These results suggest potentially promising human clinical application for coronary stenting with this polymer/drug combination.

Topics: Animals; Coronary Restenosis; Coronary Vessels; Drug Implants; Hyperplasia; Immunosuppressive Agents; Sirolimus; Stents; Swine; Tunica Intima

This study aimed at evaluating reduction in intimal hyperplasia volume following angioplasty using sirolimus-eluting stents (Cypher) compared with thin-strut bare-metal stents (Pixel) in patients with small vessels.. Eighty patients with coronary artery disease were prospectively included in two consecutive series, the first using sirolimus-eluting stents (50) and the second using bare-metal stents (30).. The use of sirolimus-eluting stents reduced: in-stent net volume obstruction [5.0% (SE = 0.77) x 39.0% (SE = 4.72), p < 0.001], in-stent late loss [0.25 mm (SE = 0.03) x 1,11 mm (SE = 0.13), p < 0.001], in-segment late loss [0.30 mm (SE = 0.04) x 0.83 mm (SE = 0.11), p < 0.001], in-stent restenosis (0% x 33.3%, p < 0.001) and in-segment restenosis (4% x 36.7%, p < 0.001). The event-free survival rate was 96% in the sirolimus-eluting stent group versus 86.7% in the bare-metal stent group (BMS) (p = 0.190).. Sirolimus-eluting stents are superior to thin-strut bare-metal stents in reducing intimal hyperplasia (less in-stent obstruction and less late lumen loss) in patients with small vessels. The use of these stents significantly reduced angiographic restenosis at eight months.

Topics: Adolescent; Adult; Angioplasty, Balloon, Coronary; Antibiotics, Antineoplastic; Coronary Restenosis; Coronary Stenosis; Drug Implants; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Metals; Middle Aged; Prospective Studies; Sirolimus; Stents; Tunica Intima

To assess the impact of expansion grade of sirolimus eluting stent on intimal hyperplasia with intravascular ultrasound (IVUS).. A total of 75 patients implanted with sirolimus eluting stents for at least 8 months were enrolled in this study and IVUS could be performed in 76 stents of 73 patients and 2 patients were excluded due to total coronary occlusion. External elastic membrane (EEM) cross-sectional areas (CSA) at stent inlet and outlet, at in-stent minimal CSA; in-stent CSA, cavity CSA, intimal area (in-stent area-cavity area), maximal and minimal diameter of stent, and symmetry index of stent (minimal diameter of stent/maximal diameter of stent) were measured.. Five out of 76 stents of 73 patients developed intimal hyperplasia and intimal proliferation was inhibited by sirolimus eluting stent in patients with either minimal stent CSA/EEM CSA < 0.5 (n = 56) or >or= 0.5 (n = 20), minimal stent CSA/reference CSA < 0.9 (n = 44) or >or= 0.9 (n = 32), minimal stent CSA < 5 mm(2) (n = 25) or CSA >or= 5 mm(2) (n = 51), symmetry index of stent at minimal CSA of stent < 0.9 (n = 37) or >or= 0.9 (n = 39) during IVUS follow up.. Sirolimus eluting stent inhibited intimal hyperplasia independent of stent expansion grade.

Topics: Coronary Angiography; Coronary Artery Disease; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Tunica Intima; Ultrasonography, Interventional

The purpose of this study was to evaluate the long-term effects of the DEVAX AXXESS biolimus eluting stent (BES) in a porcine coronary model, compared with those of bare metal stent (BMS) and polymer only stent (POS) controls.. Excessive neointimal growth has been identified as a major cause of late failure of percutaneous coronary interventions. The effect of drug eluting from self-expanding stents for prevention of neointimal hyperplasia has not been studied before. The DEVAX AXXESS is a self-expanding nickel titanium stent, coated with antiproliferative compound-biolimus.. Twenty juvenile farm swine, 25-35 kg in weight, 3-6 months in age were used. Each animal received a stent to the left anterior descending artery, left circumflex or right coronary arteries as permitted per anatomy. The chronic vascular response after BES implantation was compared with that after BMS and POS implantation at 28, 90, and 180 days follow-up.. The 28-day outcome by quantitative coronary angiography (QCA) showed significant increase in minimal luminal diameter (MLD) in the BES (MLD: 2.90 +/- 0.97, 2.39 +/- 0.90, 1.59 +/- 0.91; P = 0.009) compared with BMS and POS, respectively. By histomorphometric analysis, there was also a corresponding significant reduction in neointimal tissue proliferation in the BES (average neointimal area: 2.78 +/- 0.07, 5.46 +/- 0.66, 8.42 +/- 0.85; P = 0.002) compared with that in BMS and POS controls, respectively at 28-days follow-up. At 90 and 180 days, the mean neointimal area was not significantly different between the BES and the controls.. BES favorably modulates the neointimal tissue formation for 28 days, in the porcine coronary model. Long-term inhibition of neointimal hyperplasia is not sustained most likely because of the delayed cellular proliferation and inflammation in the vessel wall.

Topics: Alloys; Animals; Coated Materials, Biocompatible; Coronary Angiography; Hyperplasia; Immunosuppressive Agents; Models, Animal; Polyesters; Prosthesis Design; Sirolimus; Stents; Swine; Time Factors; Tunica Intima

Topics: Coronary Angiography; Coronary Disease; Coronary Restenosis; Coronary Vessels; Humans; Hyperplasia; Immunosuppressive Agents; Risk Factors; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

To investigate whether rapamycin (RPM) can reduce the neointima formation in the autologous vein graft, thus to provide support for its clinical application.. Twenty-four male rabbits were made external jugular vein-to-common carotid artery models and then were divided into 4 equal groups at random: blank-control group; F-127 control group receiving local application of 0.5 ml 20% F-127 around the vein graft; low-dose RPM group, receiving local application of 0.5 ml 20% F-127 containing RPM of 50 microg/cm(2); and high dose RPM group, receiving local application of 0.5 ml 20% F-127 containing RPM of 100 microg/cm2. The rabbits were killed 3 weeks later and the samples of vein graft bridge were taken to undergo light microscopy. The ratio of intima to media thickness and restenosis rate (ratio of lumina to lumina plus intima area) were measured. Immunohistochemistry was used to detect the proliferating cell nuclear antigen (PCNA) positive cells so as to indicate the degree of cell proliferation. The apoptosis cells were detected by TUNEL to indicate the degree of cell apoptosis.. The intima thickness levels of the low- and high-dose RPM groups were 29 microm +/- 10 microm and 16 microm +/- 8 microm respectively, both significantly lower than those of the blank-control group and F-127 control group (90 microm +/- 11 microm and 85 microm +/- 11 microm respectively, all P < 0.05). The restenosis rate (lumina area/total area ratio) of the low- and high-dose RPM groups were 0.80 +/- 0.36 and 0.91 +/- 0.13 respectively, both significantly higher than those of the blank-control group and F-127 control group (0.58 +/- 0.11 and 0.65 +/- 0.47 respectively, all P < 0.05). The cell proliferation indicis of vascular smooth muscle cells (VSMCs) of the low- and high-dose RPM groups were 20% +/- 9% and 14% +/- 6% respectively, both significantly lower than those of the blank-control group and F-127 control group (31% +/- 7% and 35% +/- 6%, all P < 0.05). The cell apoptosis indicis of the low- and high-dose RPM groups were 33% +/- 7% and 36% +/- 7% respectively, both significantly lower than those of the blank-control group and F-127 control group (16% +/- 6% and 18.% +/- 8% respectively, all P < 0.05).. Local delivery of slow-releasing RPM by F-127 effectively inhibits the neointima hyperplasia in vein graft by a mechanism of reducing the VSMC proliferation and inducing cell apoptosis.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Carotid Artery, Common; Delayed-Action Preparations; Dose-Response Relationship, Drug; Hyperplasia; Immunohistochemistry; In Situ Nick-End Labeling; Jugular Veins; Male; Proliferating Cell Nuclear Antigen; Rabbits; Random Allocation; Sirolimus; Tunica Intima

The neointimal coverage and intracoronary thrombi within stented segments at 6 months after implantation between sirolimus-eluting stents (SESs) and bare metal stents (BMSs) were compared by direct visualization using angioscopy.. Forty-six patients (36 stable angina and 10 acute coronary syndrome) were treated with 33 SESs and 33 BMSs. Immediately after and 6 months after stenting, each of the stented segments, edge body, and overlapping segment were observed by angioscopy and the grade of neointimal coverage over the stents was classified as 0: absent neointima, 1: visible struts through thin neointima, or 2: invisible struts. The existence of thrombi was also evaluated. The average grade of the neointimal coverage at 6 months follow-up was lower in the SES than that in the BMS (edge: 1.4+/-0.7 vs. 1.9+/-0.2, body: 1.0+/-0.5 vs. 1.8+/-0.5, overlapping segment: 0.6+/-0.7 vs. 1.8+/-0.5; P<0.0001, P<0.0001, P=0.0069, respectively). The frequency of persistence of thrombus was significantly higher in the SESs than that in the BMSs (86 vs. 29%, respectively; P=0.031).. The present study suggested a delayed neointimal stent coverage and slower thrombus disappearance process in the SESs in comparison to the BMSs.

Topics: Aged; Angina Pectoris; Coronary Angiography; Coronary Thrombosis; Coronary Vessels; Drug Implants; Female; Follow-Up Studies; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Observer Variation; Recurrence; Sirolimus; Stents; Tunica Intima

To investigate the effect of Sirolimus on vein graft neointima hyperplasia via oral administration compared with local delivery, and find out an effective and safe way to provide support for clinical application.. A rabbit external jugular vein-to-common carotid artery model was established. Twenty-four healthy rabbits were divided into 4 groups at random: blank-control group, F-127 control group, group 3 that received locally applied slow-releasing Sirolimus with F-127, group 4 that received oral Sirolimus (the commercial name Rapamune). The ratio of intima to medium thickness and re-stenosis rate (ratio of lumina to lumina plus intima area) were measured, PCNA positive cells by immunohistochemical staining were detected to indicate the degree of cell proliferation, and apoptosis cells detected by TUNEL.. Compared with blank-control group, neointima hyperplasia was inhibited significantly in group 3 and group 4 [intima thickness were (90.11 +/- 10.99) microm versus (29.38 +/- 10.45) microm, (18.29 +/- 9.03) microm, respectively]. Re-stenosis rate was reduced (lumina area/ total area ratio were 0. 58 +/- 0.11 versus 0.80 +/- 0.16, 0.77 +/- 0.16, respectively). Proliferation of VSMC was inhibited (cell proliferation indexes were 31.03%+/-6.80% versus 20.32% +/- 9.19%, 16.22% +/- 5.85%, respectively) and cell apoptosis level raised (cell apoptosis indexes were 16.27% +/- 6.49% versus 33.39% +/- 7.05%, 33.42% +/- 7.11%, respectively). There was no significant difference between group 3 and group 4.. Both locally applied slow-releasing Sirolimus and oral Rapamune could inhibit vein graft neointima hyperplasia; Administration via local delivery was preferred for little side-effect on the whole body. This conclusion provides support for clinical application.

Topics: Animals; Apoptosis; Carotid Artery, Common; Cell Proliferation; Coronary Restenosis; Graft Occlusion, Vascular; Hyperplasia; Immunohistochemistry; Immunosuppressive Agents; In Situ Nick-End Labeling; Jugular Veins; Male; Proliferating Cell Nuclear Antigen; Rabbits; Random Allocation; Sirolimus; Tunica Intima

A direct coronary stenting technique using drug-eluting stents may decrease drug-eluting stent efficacy due to possible damage to the surface coating of the stent. The DIRECT is a multicenter, prospective, nonrandomized trial designed to evaluate the direct stenting strategy for the sirolimus-eluting Bx-Velocity stent compared with the historical control (SIRIUS trial, stenting with predilation). Volumetric and cross-sectional intravascular ultrasound analyses at 8-month follow-up were performed in 115 patients (DIRECT n= 64, control n = 51). Patient and lesion characteristics were comparable between groups. The DIRECT group achieved an equivalent uniform expansion index, defined as minimum stent area/maximum stent area x 100, compared with the control group (65.9 +/- 11.7 vs 63.1 +/- 12.7, p = NS). At 8-month follow-up, vessel, stent, lumen, and neointimal volume index (volume in cubic millimeters/length in millimeters) and percent neointimal volume were similar between the DIRECT and control groups (vessel volume index 13.9 +/- 4.40 vs 15.0 +/- 3.83; stent volume index 6.83 +/- 2.02 vs 6.94 +/- 2.04; lumen volume index 6.71 +/- 2.04 vs 6.81 +/- 2.07; neointimal volume index 0.14 +/- 0.24 vs 0.16 +/- 0.23; percent neointimal volume 3.73 +/- 6.97 vs 3.14 +/- 5.32, p = NS for all). In addition, in-stent neointimal hyperplasia distribution was significantly smaller near the distal stent edge (0.22 vs 0.098 mm(3)/mm, p = 0.01 for an average neointimal volume index within 3 mm from the distal stent edge). In conclusion, direct coronary stenting with the sirolimus-eluting Bx-Velocity stent is equally effective in terms of uniform stent expansion and long-term quantitative intravascular ultrasound results compared with conventional stenting using predilation. This strategy appears to be associated with less neointimal hyperplasia near the distal stent edge.

Topics: Coronary Stenosis; Coronary Vessels; Dilatation; Female; Humans; Hyperplasia; Male; Middle Aged; Prospective Studies; Sirolimus; Stents; Ultrasonography, Interventional

The neointimal hyperplasia (IH) distribution pattern of in-stent restenotic lesions after sirolimus-eluting stent (SES) implantation has not been well described. We identified 48 in-stent restenotic lesions (41 patients) after SES implantation and performed volumetric intravascular ultrasound analyses. Lumen area, stent area, and IH area at the minimal lumen area site were 2.7 +/- 1.0, 5.4 +/- 1.9, and 2.7 +/- 1.4 mm(2), respectively. IH area at the minimal lumen site was larger in the group with a stent area > or =5.0 mm(2) than the group with a stent area <5.0 mm(2) (3.7 +/- 1.3 vs 1.9 +/- 0.8 mm(2), p <0.001). There were fewer visualized stent struts in lesions with a minimum stent area > or =5.0 mm(2) at the minimum lumen site compared with those with a stent area <5.0 mm(2) (0.69 +/- 0.25 vs 0.83 +/- 0.16, p = 0.04). When we compared lesions in patients with diabetes mellitus with patients without diabetes, minimum lumen areas, percent IH at minimal lumen area, percent IH, and neointima-free stent length were identical. In conclusion, (1) lesions without SES underexpansion at the minimum lumen site had more IH and greater nonuniform stent strut distribution compared with restenotic SESs that were underexpanded, and (2) the IH response did not appear to be more aggressive in patients with diabetes mellitus than in those without diabetes mellitus.

Topics: Aged; Coronary Restenosis; Coronary Vessels; Diabetes Complications; Female; Humans; Hyperplasia; Male; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

Rapamycin is an immunosuppressive agent with marked antiproliferative properties and is effective in reducing in stent restenosis and vein graft neointimal hyperplasia. Apoptosis is one mechanism counterbalancing cellular proliferation. We therefore investigated the role of apoptosis in rapamycin treated vein grafts in a mouse model.. C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a cuff technique. In the treatment group 200 microg of rapamycin were applied locally in pluronic gel. The control group did not receive local treatment. Vein grafts were harvested at 4 weeks postoperatively and underwent morphometric analysis as well as immunohistochemical analysis for apoptosis (TUNEL).. In grafted veins without treatment (controls) neointimal thickness was 50 (12-58) microm at 4 weeks postoperatively. In 200 microg rapamycin treated grafts the neointimal thickness was 17 (5-55) microm. Rapamycin treated vein grafts showed a significantly increased rate of apoptosis in the adventitia as compared with controls (P=0.032). In the neointima the apoptosis rate was lower in both groups with no significant difference between rapamycin treated grafts and controls.. We conclude that treatment of experimental vein grafts with rapamycin is associated with an increased apoptosis rate in the vascular wall and a trend towards reduction of neointimal hyperplasia. These results suggest that apoptosis may be a beneficial antiproliferative component for the treatment of vein graft disease.

Topics: Animals; Apoptosis; Coronary Restenosis; Graft Occlusion, Vascular; Hyperplasia; Immunosuppressive Agents; In Situ Nick-End Labeling; Mice; Mice, Inbred BALB C; Sirolimus; Stents; Tunica Intima

The patency of arteriovenous (AV) expanded polytetrafluoroethylene (ePTFE) hemodialysis grafts is severely compromised by intimal hyperplasia (IH) at the venous anastomosis and in the venous outflow tract. We addressed the potential of primary placement of a sirolimus-eluting stent (SES) in a validated porcine model.. In 25 pigs, ePTFE AV grafts were created bilaterally between the carotid artery and the jugular vein, whereupon a self-expandable nitinol stent (14 SESs and 11 bare-metal stents) was implanted over the venous anastomosis in 1 of the 2 grafts. After exclusion of technical failures and 1 unilateral occlusion, 16 pigs (9 SESs and 7 bare-metal stents) were included for further analysis. After 28 days, we measured graft flow and performed quantitative angiography. The pigs were then euthanized, and grafts with adjacent vessels were excised for histological analysis. Minimal luminal diameter was substantially larger in the SES group compared with unstented controls (5.9+/-0.2 versus 3.8+/-0.4 mm, respectively, P=0.01), which was accompanied by more prominent graft flow (SES, 1360+/-89 mL/min versus unstented, 861+/-83 mL/min, P=0.05). IH at the venous anastomosis was 77% less in the SES group compared with unstented controls (0.44+/-0.05 versus 1.92+/-0.5 mm2, respectively, P=0.01), whereas IH increased markedly when bare-metal stents were used (5.7+/-1.4 mm2, P=0.05).. SESs in the venous outflow of AV grafts significantly reduce IH and increase vessel diameter and graft flow compared with unstented grafts. These findings suggest that SESs have the potential to improve primary patency of AV grafts in hemodialysis patients.

Topics: Animals; Arteriovenous Anastomosis; Blood Vessel Prosthesis; Follow-Up Studies; Hyperplasia; Models, Animal; Polytetrafluoroethylene; Regional Blood Flow; Renal Dialysis; Sirolimus; Stents; Swine; Tunica Intima

The serine/threonine kinase AKT and its downstream mediator mammalian target of rapamycin (mTOR) are activated in lung adenocarcinoma, and clinical trials are under way to test whether inhibition of mTOR is useful in treating lung cancer. Here, we report that mTOR inhibition blocked malignant progression in K-ras(LA1) mice, which undergo somatic activation of the K-ras oncogene and display morphologic changes in alveolar epithelial cells that recapitulate those of precursors of human lung adenocarcinoma. Levels of phospho-S6(Ser236/235), a downstream mediator of mTOR, increased with malignant progression (normal alveolar epithelial cells to adenocarcinoma) in K-ras(LA1) mice and in patients with lung adenocarcinoma. Atypical alveolar hyperplasia, an early neoplastic change, was prominently associated with macrophages and expressed high levels of phospho-S6(Ser236/235). mTOR inhibition in K-ras(LA1) mice by treatment with the rapamycin analogue CCI-779 reduced the size and number of early epithelial neoplastic lesions (atypical alveolar hyperplasia and adenomas) and induced apoptosis of intraepithelial macrophages. LKR-13, a lung adenocarcinoma cell line derived from K-ras(LA1) mice, was resistant to treatment with CCI-779 in vitro. However, LKR-13 cells grown as syngeneic tumors recruited macrophages, and those tumors regressed in response to treatment with CCI-779. Lastly, conditioned medium from primary cultures of alveolar macrophages stimulated the proliferation of LKR-13 cells. These findings provide evidence that the expansion of lung adenocarcinoma precursors induced by oncogenic K-ras requires mTOR-dependent signaling and that host factors derived from macrophages play a critical role in adenocarcinoma progression.

Topics: Adenocarcinoma; Adenoma; Animals; Cell Line, Tumor; Cell Transformation, Neoplastic; Disease Progression; Enzyme Activation; Genes, ras; Hyperplasia; Lung Neoplasms; Macrophages, Alveolar; Mice; Mutation; Precancerous Conditions; Protein Kinase Inhibitors; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pulmonary Alveoli; Ribosomal Protein S6 Kinases; Sirolimus; TOR Serine-Threonine Kinases

To evaluate the efficacy of limited short-term systemic administration of rapamycin to prevent neointimal intimal hyperplasia (NIH) in a double-injury rat model of restenosis.. Aortic lesions were induced by perivascular placement of silicone cuffs around the aorta of 36 Lewis rats. After 3 weeks, the cuffs were removed, and the vessels were subjected to secondary balloon injury. Rapamycin (sirolimus) was intravenously administered for 5 days in dosages of 0.5 or 2 mg/kg/d beginning at various time points relative to the balloon injury: (1) days -2 to +2, (2) days 1 to 5, or (3) days 7 to 11. For each treatment period, 6 rats received the 5-day course of the lower or higher dose of rapamycin. Eight rats served as controls undergoing 2-stage injury without rapamycin treatment. Morphometry and immunohistochemistry were performed at 21 days after angioplasty.. NIH and intimal alpha-actin expression were inhibited by both dosages when treatment started 2 days before or 1 day after angioplasty. Results were statistically significant for the lower dose when started 1 day after angioplasty (p < 0.01) and for the higher dose when initiated 2 days before the intervention (p < 0.05). Treatment commencing at 7 days did not reduce NIH in either dosage group.. In a double-injury rat model, NIH can be inhibited by short-term systemic rapamycin, but suppression of early cell migration and proliferation is pivotal. A limited peri-interventional antiproliferative therapy may be of value as an adjunct to control restenosis after balloon angioplasty and/or stenting.

Topics: Actins; Angioplasty, Balloon; Animals; Aorta, Abdominal; Arterial Occlusive Diseases; Cell Count; Disease Models, Animal; Dose-Response Relationship, Drug; Follow-Up Studies; Hyperplasia; Immunosuppressive Agents; Male; Muscle, Smooth, Vascular; Rats; Rats, Inbred Lew; Secondary Prevention; Sirolimus; Time Factors; Treatment Outcome; Tunica Intima

Although effective coverage of challenging coronary lesions has warranted the use of overlapping drug-eluting stents, the histopathological response to stent overlap is unknown.. The arterial reaction to overlapping Cypher or Taxus drug-eluting stents was examined in rabbits with bare metal stents, BxVelocity or Express, serving as controls. Single iliac artery balloon injury was followed by placement of 2 overlapping 3.0-mm-diameter drug-eluting stents or bare metal stents in 60 animals (mean length of overlap, 9.8+/-3.6 mm). Stented arteries were harvested at 28 and 90 days for histology. Overlapped segments exhibited delayed healing compared with proximal and distal nonoverlapping sites at 28 days. Overlapped segments in Taxus stents induced significantly more luminal heterophils/eosinophils and fibrin deposition than Cypher; peristrut giant cell infiltration, however, was more frequent in the latter. Overlapping bare metal stents also showed mild delayed healing compared with nonoverlapped segments, but not to the same extent as drug-eluting stents. Although neointimal thickness within the overlap was similar in 28- and 90-day Cypher stents, there was a significant increase with Taxus (P=0.03).. Compared with bare metal stents, drug-eluting stents further delay arterial healing and promote inflammation at sites of overlap. Taxus stents induced greater fibrin deposition, medial cell loss, heterophils/eosinophils, and late neointimal hyperplasia. Patients receiving overlapping drug-eluting stents need more frequent follow-up than patients with nonoverlapping stents.

Topics: Animals; Catheterization; Drug Therapy, Combination; Fibrin; Hyperplasia; Iliac Artery; Inflammation; Paclitaxel; Rabbits; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Wound Healing

This study sought to evaluate the long-term arterial response after sirolimus-eluting stent implantation.. Sirolimus-eluting stents are effective in inhibiting neointimal hyperplasia without affecting plaque volume behind the stent struts at six months.. Serial quantitative intravascular ultrasound and computer-assisted grayscale value analysis over four years were performed in 23 event-free patients treated with sirolimus-eluting stents.. In the first two years, the mean plaque volume (155.5 +/- 42.8 mm3 post-procedure and 156.8 +/- 57.7 mm3 at two years, p = 0.86) and plaque compositional change expressed as mean percent hypoechogenic tissue of the plaque behind the stent struts (78.9 +/- 8.6% post-procedure and 78.2 +/- 8.9% at two years, p = 0.67) did not significantly change. However, significant plaque shrinking (change in plaque volume = -18.4 mm3, p = 0.02) with an increase in plaque echogenicity (change in percent hypoechogenic tissue = -7.8%, p < 0.0001) was observed between two and four years. The mean neointimal volume increased over four years from 0 to 8.4 +/- 5.8 mm3 (p < 0.0001). However, no further statistically significant change occurred between two and four years (7.0 +/- 6.7 mm3 vs. 8.4 +/- 5.8 mm3, p = 0.25).. Between two and four years after sirolimus-eluting stent implantation, peri-stent tissue shrank with a concomitant increase in echogenicity. These intravascular ultrasound findings suggest that late chronic artery responses may evolve for up to four years after sirolimus-eluting stent implantation. In addition, the fact that the neointima does not significantly change from two to four years may suggest that the biological phenomenon of a delayed healing response has begun to subside.

Topics: Combined Modality Therapy; Coronary Artery Disease; Diagnosis, Computer-Assisted; Drug Delivery Systems; Female; Humans; Hyperplasia; Male; Middle Aged; Sirolimus; Stents; Time Factors; Tunica Intima; Ultrasonography, Interventional

Sirolimus and paclitaxel eluted from stents inhibit cell proliferation and other cellular processes by dramatically different mechanisms. In this study, the effects of sirolimus and paclitaxel on cultured human coronary artery smooth muscle and endothelial cell function or cell cycle changes in balloon-injured arteries were directly compared. Both sirolimus and paclitaxel inhibited smooth muscle and endothelial cell proliferation. However, only paclitaxel inhibited smooth muscle and endothelial cell migration at low (nM) concentrations. Sirolimus arrested smooth muscle and endothelial cells in the G0/G1 phase of the cell cycle without inducing apoptosis while paclitaxel produced apoptosis in both cell types at low nanomolar concentrations. Although both agents blocked neointimal formation, sirolimus applied locally to injured rat carotid arteries increased the percentage of cycling vascular cells in G0/G1 without inducing apoptosis while paclitaxel increased the percentage of cycling cells in S and G2/M phases while inducing apoptosis. These results suggest that sirolimus reduces neointimal hyperplasia through a cytostatic mechanism while paclitaxel produces apoptotic cell death.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Carotid Artery Injuries; Cell Cycle; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Coronary Vessels; Dose-Response Relationship, Drug; Drug Delivery Systems; Endothelial Cells; Hyperplasia; Male; Muscle, Smooth, Vascular; Paclitaxel; Rats; Rats, Inbred Lew; Sirolimus; Stents; Tunica Intima

We tested the hypothesis that rapamycin coated onto, and eluted from, expanded polytetrafluoroethylene (ePTFE) grafts would diminish neointimal hyperplasia in a porcine model.. Rapamycin (also called sirolimus) was coated onto the luminal surface of 6-mm-internal-diameter thin-walled ePTFE grafts by using an adhesive polymer that allows timed release of the drug. An adhesive polymer that allows timed release of rapamycin from ePTFE was developed with commercially available chemicals and applied on 6-mm ePTFE grafts. Graft integrity was characterized by scanning electron microscopy, and rapamycin levels were quantified by using high-performance liquid chromatography. Twenty-two mongrel pigs were randomized into three groups: untreated ePTFE (n = 6), adhesive-only coated ePTFE (n = 6), or adhesive- and rapamycin-coated ePTFE (n = 10). End-to-side unilateral aortoiliac bypasses were performed by using 6-mm-internal-diameter ePTFE grafts and standardized anastomotic lengths. Unilateral end-to-side aortoiliac ePTFE grafts (6-mm internal diameter) were inserted by using polypropylene sutures, 6-0 proximally and 7-0 distally; all anastomoses were 12 mm long. All animals received aspirin (325 mg orally) daily. All animals were given oral aspirin (325 mg) daily beginning on the day before surgery. At 28 days, the animals were killed, and the grafts were explanted in continuity with the adjacent aortic cuff and the outflow iliac artery. Variables compared between groups included graft patency, distal anastomotic length and cross-sectional narrowing, and intimal thickness at the arterial-graft junction indexed to the adjacent graft thickness. Microscopic analysis was performed with hematoxylin and eosin and Masson trichrome stains on paraffin sections. A pathologist blinded to experimental groups graded sections for collagen deposition, neointima formation, inflammatory cellular infiltrates, medial necrosis, and aneurysmal degeneration.. All animals survived until they were killed without clinical evidence of limb ischemia or graft infection. Preplanned t tests in the context of one-way analysis of variance showed no difference in outcome measures between the untreated ePTFE and adhesive-only coated ePTFE groups; therefore, they were combined in further comparisons with the adhesive- and rapamycin-coated ePTFE group. The Rapamycine eluting expanded polytetrafluoroethylene group had longer anastomoses (85.6% vs 60.6% of the initial anastomotic length maintained; P < .0001) and less cross-sectional narrowing in the outflow graft (16.2% vs 28.5%; P = .0007) when compared with the other two groups by using two-tailed Student t tests. There was no evidence of medial necrosis or aneurysmal degeneration. All patent grafts had complete endothelialization on hematoxylin and eosin sections. Rapamycin was detectable and quantifiable in the arterial wall at 28 days after implantation.. Rapamycin can be coated onto and eluted from ePTFE by using a nonionic polymer and a simple coating technique. At 4 weeks after implantation, the rapamycin-eluting ePTFE grafts demonstrate gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with non-drug-eluting ePTFE. Four weeks after implantation in a porcine model, rapamycin-eluting ePTFE grafts demonstrated gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with untreated and adhesive-only coated ePTFE grafts.. Rapamycin-eluting ePTFE grafts decrease neointimal hyperplasia in a porcine model. Further studies are needed to evaluate whether patency will be improved. Rapamycin-eluting ePTFE grafts may allow the use of prosthetic grafts in situations in which autologous vein is unavailable and in which neointimal hyperplasia is pronounced, such as in small-diameter (<6-mm) vessels typical of infrapopliteal interventions.

Topics: Anastomosis, Surgical; Animals; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Coated Materials, Biocompatible; Graft Occlusion, Vascular; Hyperplasia; Immunosuppressive Agents; Male; Microscopy, Electron, Scanning; Polytetrafluoroethylene; Sirolimus; Tunica Intima

Modern immunosuppressive agents such as tacrolimus and rapamycin are claimed to be associated with a reduction in vascular narrowing, a central feature of chronic rejection. This study assesses the effect of cyclosporine, tacrolimus and rapamycin on the development of intimal thickening, fibrosis-associated genes and deposition of extracellular matrix (ECM) proteins in a model of intimal hyperplasia. Male Sprague-Dawley rats received either no treatment or 5 mg/kg cyclosporine, 0.1 mg/kg tacrolimus or 0.05 mg/kg rapamycin. Animals underwent left common carotid balloon angioplasty, and intima medial ratios, pro-fibrotic gene expression and ECM accumulation were calculated at 14 and 28 days. Cyclosporine was associated with increased intimal thickening compared to controls ( P < 0.004). Tacrolimus had no effect on intimal thickening, whilst rapamycin significantly inhibited intimal thickening at both 14 and 28 days ( P < 0.004 and P < 0.026, respectively). All groups significantly inhibited matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1, transforming growth factor (TGF)-beta and collagen III expression at 14 days ( P < 0.001), but increased ECM deposition. However, rapamycin marginally reduced ECM deposition compared to cyclosporine ( P < 0.06). Treatment with cyclosporine was associated with worsening of vascular narrowing, whilst rapamycin showed a beneficial reduction in intimal thickening. Treatment with all immunosuppressive agents resulted in increased ECM deposition. Rapamycin may halt the progression of vascular narrowing compared to both cyclosporine and tacrolimus.

Topics: Angioplasty, Balloon; Animals; Carotid Artery, Common; Collagen Type III; Cyclosporine; Extracellular Matrix Proteins; Fibrosis; Gene Expression; Hyperplasia; Immunosuppressive Agents; Male; Matrix Metalloproteinase Inhibitors; Rats; Rats, Sprague-Dawley; Sirolimus; Tacrolimus; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta; Tunica Intima

Drug-eluting stents have been investigated as a treatment option for in-stent restenosis after bare metal stenting. However, it remains unclear whether overlapping drug-eluting stents have a toxic effect on the vessel wall. The aim of this study was to analyze the 1-year intravascular ultrasound findings after 2 overlapping sirolimus-eluting stent implantations in patients with in-stent restenosis lesions. Eight patients required 2 sirolimus-eluting stents, 18 mm in length, for full lesion coverage; these stents were implanted with >1-mm overlap. At 1-year follow-up, there were no significant quantitative changes in intravascular ultrasound measurements within the overlapped segment.

Topics: Coronary Restenosis; Coronary Vessels; Drug Delivery Systems; Female; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Retrospective Studies; Sirolimus; Stents; Ultrasonography

Rapamycin is an immunosuppressive agent which also exhibits marked antiproliferative properties. Rapamycin coated stents have been demonstrated to suppress restenosis in experimental and clinical studies of percutaneous coronary catheter intervention. We investigated whether rapamycin can reduce neointima formation in a mouse model of vein graft disease.. C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a previously described cuff technique. In the treatment group, 100 microg or 200 microg of rapamycin was applied locally in pluronic gel. The control group did not receive local treatment. Grafts were harvested at 1, 2, 4, and 6 weeks and underwent morphometric analysis as well as immunohistochemical analysis.. In grafted veins without treatment (controls), median intimal thickness was 9.6 (6.4 to 29)microm, 11.9 (7.9 to 39.9)microm, 46.6 (12.4 to 57.7)microm, and 57.5 (32.5 to 71.1)microm after 1, 2, 4, and 6 weeks, respectively. Treatment with 100 microg or 200 microg rapamycin showed a dose dependent reduction of intimal thickness. In the 200 microg rapamycin treatment group the intimal thickness was 4.3 (3.4 to 5.6)microm, 3.8 (3.2 to 6.3)microm, 17.1 (4.8 to 63)microm, and 33.9 (11.3 to 80.3)microm after 1, 2, 4, and 6 weeks, respectively. This difference of intimal thickness of 200 microg treated animals compared with controls was statistically significant at 1 and 2 weeks. Immunohistochemically the reduction of intimal thickness was associated with a decreased amount of infiltration of CD-8 positive cells and a decreased amount of metallothionein positive cells in the rapamycin treated grafts.. We conclude that perivascular application of rapamycin inhibits neointimal hyperplasia of vein grafts in a mouse model. These results suggest that rapamycin may have a therapeutic potential for the treatment of vein graft disease.

Topics: Animals; Coronary Restenosis; Disease Models, Animal; Excipients; Hyperplasia; Immunohistochemistry; Immunosuppressive Agents; Male; Mice; Mice, Inbred C57BL; Poloxamer; Sirolimus; Tunica Intima

Myointimal hyperplasia (MIH) after vascular intervention is a major problem. Recent reports describing elimination of within-stent restenosis by means of rapamycin-eluting stents prompted us to examine the effect of systemic oral rapamycin on MIH induced by arterial trauma. We studied the effect of oral rapamycin on MIH after rabbit aorta balloon injury. Thirty-five New Zealand white rabbits (2.5-3 kg) had aortic injury and were given either no rapamycin (control), 0.1 (low dose) rapamycin mg/kg/day, or 0.4 mg/kg/day (high dose). Rapamycin was started 1 week before injury and continued for 3 (4 weeks total) or 6 weeks (7 weeks total) post-injury. Sections were analyzed to measure aortic intima/media area ratios (I:M) at either 3 or 6 weeks. At 3 weeks, the I:M (mean +/- SD) for controls was 0.53 +/- 0.1; for low dose, 0.17 +/- 0.13; and for high dose, 0.24 +/- 0.07 (p < 0.001 vs. control). At 6 weeks, the I:M for controls was 0.52 +/- 0.12; for low dose-4 weeks, 0.29 +/- 0.15; low dose-7 weeks, 0.33 +/- 0.07; and high dose-4 weeks, 0.47 +/- 0.16. At 6 weeks only the difference between the low dose-4 weeks and control I:M ratios was significant (p = 0.018). The results confirm earlier studies showing that systemic rapamycin inhibits MIH after arterial injury when drug therapy is started before injury. Therapy for 3 or 6 weeks after injury yields similar inhibition, indicating that exposure to the drug early in the response to injury is more important than prolonged exposure. We observed a paradoxical relation between dose and degree of MIH inhibition, with the low dose being more effective than the high dose at both time intervals studied. Overall, the results suggest that oral rapamycin therapy might be a useful adjunct to clinical interventions at risk for development of MIH.

Topics: Administration, Oral; Animals; Antibiotics, Antineoplastic; Aorta; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Hyperplasia; Models, Cardiovascular; Rabbits; Sirolimus; Time Factors; Tunica Intima

Topics: Coronary Angiography; Coronary Stenosis; Drug Implants; Humans; Hyperplasia; Immunosuppressive Agents; Male; Middle Aged; Proteoglycans; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

The Akt/mammalian target of rapamycin (mTOR)/4E-BP1 pathway is considered to be a central regulator of protein synthesis, involving the regulation of cell proliferation, differentiation, and survival. The inhibitors of mTOR as anticancer reagents are undergoing active evaluation in various malignancies including breast cancer. However, the activation status of the Akt/mTOR/4E-BP1 pathway and its potential roles in breast cancers remain unknown. Thus, we examined 165 invasive breast cancers with specific antibodies for the phosphorylation of Akt, mTOR, and 4E-BP1 by immunohistochemistry and compared them with normal breast epithelium, fibroadenoma, intraductal hyperplasia, and ductal carcinoma in situ. We discovered that the phosphorylation of Akt, mTOR, and 4E-BP1 increased progressively from normal breast epithelium to hyperplasia and abnormal hyperplasia to tumor invasion. Phosphorylated Akt, mTOR, and 4E-BP1 were positively associated with ErbB2 overexpression. Survival analysis showed that phosphorylation of each of these three markers was associated with poor disease-free survival independently. In vitro, we further confirmed the causal relationship between ErbB2 overexpression and mTOR activation, which was associated with enhanced invasive ability and sensitivity to a mTOR inhibitor, rapamycin. Our results, for the first time, demonstrate the following: (a) high levels of phosphorylation of Akt, mTOR, and 4E-BP1 in breast cancers, indicating activation of the Akt/mTOR/4E-BP1 pathway in breast cancer development and progression; (b) a link between ErbB2 and the Akt/mTOR/4E-BP1 pathway in breast cancers in vitro and in vivo, indicating the possible role of Akt/mTOR activation in ErbB2-mediated breast cancer progression; and (c) a potential role for this pathway in predicting the prognosis of patients with breast cancer, especially those treated with mTOR inhibitors.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Antibiotics, Antineoplastic; Biomarkers, Tumor; Breast Neoplasms; Carcinoma, Intraductal, Noninfiltrating; Carrier Proteins; Cell Cycle Proteins; Cell Proliferation; Disease Progression; Female; Gene Expression Profiling; Genes, erbB-2; Humans; Hyperplasia; Immunohistochemistry; Middle Aged; Neoplasm Invasiveness; Phosphoproteins; Phosphorylation; Protein Kinases; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Sirolimus; Survival Analysis; TOR Serine-Threonine Kinases

Little is known about causes of intimal hyperplasia (IH) after sirolimus-eluting stent (SES) implantation.. Intravascular ultrasound was performed in 24 lesions with intra-SES restenosis and a comparison group of 25 nonrestenotic SESs. To assess stent strut distribution, the maximum interstrut angle was measured with a protractor centered on the stent, and the visible struts were counted and normalized for the number of stent cells. In SES restenosis patients, minimum lumen site was compared with image slices 2.5, 5.0, 7.5, and 10.0 mm proximal and distal to this site. The minimum lumen site had a smaller IVUS lumen area at follow-up (2.7+/-0.9 versus 6.2+/-1.9 mm2; P<0.01), larger maximum interstrut angle (135+/-39 degrees versus 72+/-23 degrees; P<0.01), larger IH area (3.4+/-1.5 versus 0.6+/-1.1 mm2; P<0.01) and thickness (0.7+/-0.3 versus 0.1+/-0.2 mm; P<0.01) at maximum interstrut angle, and fewer stent struts (4.9+/-1.0 versus 6.0+/-0.5; P<0.01) even when normalized for the number of stent cells (0.78+/-0.15 versus 0.97+/-0.07; P<0.01). Compared with nonrestenotic SES, the restenosis lesions also had a smaller minimal lumen area, larger IH area, thicker IH at maximum interstrut angle, fewer stent struts, and larger maximum interstrut angle. Multivariate analysis identified the number of visualized stent struts normalized for the number of stent cells and maximum interstrut angle as the only independent IVUS predictor of IH cross-sectional area (P<0.01 and P<0.01), minimum lumen area (P<0.01 and P<0.01), and IH thickness (P<0.01 and P<0.01).. The number and distribution of stent struts affect the amount of neointima after SES implantation.

Topics: Aged; Angioplasty, Balloon, Coronary; Coronary Angiography; Coronary Restenosis; Coronary Stenosis; Drug Implants; Equipment Design; Equipment Failure; Female; Humans; Hyperplasia; Male; Middle Aged; Single-Blind Method; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

Intravascular ultrasound studies were performed at angiographic follow-up on 121 native coronary lesions treated with 1 bare metal stent (n = 50), high-dose dexamethasone-eluting stents (n = 18), non-polymer-based paclitaxel-eluting stents (n = 18), or sirolimus-eluting stents (n = 35). Paclitaxel- and sirolimus-eluting stents reduced mean intimal hyperplasia thickness compared with bare metal stents by 49% and 90% (p = 0.048 and p <0.001), respectively, whereas mean intimal hyperplasia thickness treated with dexamethasone-eluting stents was similar to those lesions treated with bare metal stents.

Topics: Coronary Restenosis; Coronary Vessels; Dexamethasone; Humans; Hyperplasia; Paclitaxel; Prosthesis Design; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

In this study, we assess the value of sirolimus eluting stent (SES) implantation in patients with complex in-stent restenosis (ISR).. The treatment of ISR remains a therapeutic challenge, since many pharmacological and mechanical approaches have shown disappointing results. The SESs have been reported to be effective in de-novo coronary lesions.. Sixteen patients with severe, recurrent ISR in a native coronary artery (average lesion length 18.4 mm) and objective evidence of ischemia were included. They received one or more 18 mm Bx VELOCITY SESs (Cordis Waterloo, Belgium). Quantitative angiographic and three-dimensional intravascular ultrasound (IVUS) follow-up was performed at four months, and clinical follow-up at nine months.. The SES implantation (n = 26) was successful in all 16 patients. Four patients had recurrent restenosis following brachytherapy, and three patients had totally occluded vessels preprocedure. At four months follow-up, one patient had died and three patients had angiographic evidence of restenosis (one in-stent and two in-lesion). In-stent late lumen loss averaged 0.21 mm and the volume obstruction of the stent by IVUS was 1.1%. At nine months clinical follow-up, three patients had experienced four major adverse cardiac events (two deaths and one acute myocardial infarction necessitating repeat target vessel angioplasty).. The SES implantation in patients with severe ISR lesions effectively prevents neointima formation and recurrent restenosis at four months angiographic follow-up.

Topics: Adult; Aged; Coronary Angiography; Coronary Restenosis; Female; Humans; Hyperplasia; Male; Middle Aged; Recurrence; Sirolimus; Stents; Treatment Outcome; Tunica Intima; Ultrasonography

This study evaluates the response of the coronary vessel wall to implantation of the sirolimus-eluting stent (SES), Bx-VELOCITY, by using serial intravascular ultrasound. SESs have a major impact on the inhibition of in-stent neointimal hyperplasia. However, changes in the vessel wall and behind stent struts in animal models and humans have not been evaluated after SES implantation. Thirty-four patients who received a SES (n = 24) or a Bx-VELOCITY bare stent (BS) (n = 10) for single de novo coronary lesions and had serial motorized pullback 3-dimensional intravascular ultrasound were included. Stent, lumen, and vessel volumes were similar in the 2 groups at baseline. At follow-up, significantly larger lumen and lower neointimal hyperplasia volumes (0.7 vs 33 mm(3), p = 0.001) were seen in the SES group compared with the BS group. There was no significant difference between SES and BS in either the vessel volume (+2.4% vs +0.7%, p = NS) or the plaque behind stent volume change (+3.4% vs +2.5%, p = NS) from after the procedure to late follow-up. The stent edges also showed no significant difference between postprocedural and follow-up measurements, either in patients receiving SESs or BSs. No stented or edge segment required redilatation in the SES group, whereas 2 patients underwent repeat percutaneous coronary angioplasty in the BS group. In the SES group, 1 patient (4%) showed late acquired incomplete stent apposition. Thus, the SES is effective in inhibiting neointimal hyperplasia without affecting vessel volume and plaque behind the stent.

Topics: Angioplasty, Balloon, Coronary; Coronary Disease; Coronary Vessels; Female; Follow-Up Studies; Humans; Hyperplasia; Imaging, Three-Dimensional; Male; Middle Aged; Sirolimus; Stents; Tunica Intima; Ultrasonography, Interventional

Allograft vasculopathy remains the leading cause of late allograft failure following transplantation and can be inhibited by the antiproliferative drug rapamycin. This study assessed the efficacy of combining rapamycin therapy with calcineurin inhibition.. Male Sprague-Dawley rats received rapamycin 0.05 mg/kg daily and either tacrolimus 0.1 mg/kg or cyclosporin 5 mg/kg daily, and findings were compared with those in an untreated control group. Animals underwent left common carotid artery balloon angioplasty; the artery was explanted after 2 weeks. Morphometric analysis was performed on transverse sections and the intima : media ratio was calculated. Profibrotic gene expression was measured with competitive reverse transcriptase-polymerase chain reaction at 14 and 28 days. Proliferation was determined with proliferating cell nuclear antigen at 14 and 28 days. Extracellular matrix deposition was quantified with Sirius red.. The combination of rapamycin and tacrolimus was associated with the greatest reduction in intimal thickening. Furthermore, treatment with rapamycin and tacrolimus significantly attenuated extracellular matrix deposition compared with rapamycin and cyclosporin (P < 0.02).. The effects of rapamycin in combination with tacrolimus were better than those observed with rapamycin and cyclosporin.

Topics: Animals; Calcineurin Inhibitors; Carotid Artery, Common; Cell Division; Cyclosporine; Drug Therapy, Combination; Hyperplasia; Immunosuppressive Agents; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Rats; Rats, Sprague-Dawley; Sirolimus; Tacrolimus; Tissue Inhibitor of Metalloproteinase-1; Tunica Intima

Topics: Angioplasty, Balloon, Coronary; Coronary Disease; Coronary Restenosis; Coronary Vessels; Humans; Hyperplasia; Immunosuppressive Agents; Randomized Controlled Trials as Topic; Sirolimus; Stents

Topics: Anti-Bacterial Agents; Coated Materials, Biocompatible; Coronary Vessels; Humans; Hyperplasia; Polymers; Sirolimus; Stents; Tunica Intima

Immunosuppressive agents have been proposed to reduce neointimal hyperplasia in synthetic vascular grafts. Thus, the purpose of the present study was to evaluate the safety and efficacy of rapamycins (systemic vs. local vs. oral administration) and mycophenolate mofetil (MMF) to reduce intimal hyperplasia in infrarenal synthetic vascular grafts of the rat.. Fifty-four Wistar rats (250 g) completed the study after a synthetic vascular graft (ePTFE, Gore-tex, 2 mm diameter, 10 mm length) was implanted end-to-end in the infrarenal aorta. The animals were divided into three groups: group 1 consisted of 12 control animals, group 2 consisted of 37 rats receiving rapamycins, either per os (RAD, 1.5 or 3 mg/kg), intraperitoneally (RPM, 1.5 or 3 mg/kg) or locally (RPM soaking of the graft); and in group 3 (n=5), MMF (40 mg/kg) was administered orally. The animals were followed weekly with weight controls and signs of toxicity for 30 (n=37) and 60 (n=17) days, respectively. All animals were sacrificed and underwent histological examination at completion of the study.. All animals survived in groups 1 and 3, but five died in group 2. The weight gain was normal in all groups, except for the subgroup 2a receiving high dose rapamycins orally. All rats in group 3 suffered from diarrhea, whereas animals receiving high dose rapamycins showed toxic signs (hair loss, wound healing problems). Histological examination showed a significant increase in intimal hyperplasia in group 1 (0.03+/-0.01 and 0.14+/-0.05 microm after 30 and 60 days, respectively; P<0.01). Rapamycins in either application or dosage had no significant effect on intimal hyperplasia.. Local or systemic administration of rapamycins has no effect on intimal hyperplasia in synthetic vascular grafts. In contrast, toxic signs with weight loss were observed in animals treated with high dose rapamycins, but not in those treated with MMF. Thus, in the rat model, immunosuppression with rapamycins or MMF cannot be recommended for the prevention of intimal hyperplasia in the synthetic vascular graft model.

Topics: Anastomosis, Surgical; Animals; Blood Vessel Prosthesis; Hyperplasia; Immunosuppressive Agents; Models, Animal; Mycophenolic Acid; Polytetrafluoroethylene; Rats; Rats, Wistar; Sirolimus; Tunica Intima; Vascular Patency

Rapamycin, an immunosuppressant and antiproliferative agent, reduces intimal hyperplasia after arterial injury in animal models and in a preliminary study in humans. Rapamycin treatment reportedly increases expression of p27, a cyclin-dependent kinase inhibitor. This mechanism was tested using a p27-deficient (p27 -/-) murine model. Aortic smooth muscle cells from wild-type (WT) and p27 -/- mice were isolated and cultured. Cell proliferation, assessed by cell count and (3)H-thymidine incorporation, was inhibited significantly by rapamycin in WT and p27 -/- cells at concentrations of 1 ng/ml, 10 ng/ml, and 100 ng/ml (p < 0.05, versus control). The in vivo effect on intimal hyperplasia was studied in p27 -/- and WT mice after femoral artery transluminal injury. Rapamycin treatment was started 2 days before injury and maintained for 2 weeks (1 mg/kg per 48 hours, ip). No significant differences in intima-to-media ratio were found between WT (1.1 +/- 0.1) and p27 -/- mice (1.0 +/- 0.1) 4 weeks after injury. Rapamycin significantly (p < 0.05) reduced intima-to-media ratios in both WT (0.7 +/- 0.1) and p27 -/- mice (0.5 +/- 0.1), compared with untreated mice. p27 deficiency did not alter the arterial wall proliferative response to injury. The inhibitory effect of rapamycin on intimal hyperplasia occurred via a p27-independent mechanism. The in vitro data showed that this effect was mediated through decreased proliferation and enhanced apoptosis.

Topics: Animals; Aorta; Apoptosis; Cell Cycle Proteins; Cell Division; Cyclin-Dependent Kinase Inhibitor p27; Female; Gene Deletion; Hyperplasia; Immunosuppressive Agents; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microtubule-Associated Proteins; Muscle, Smooth, Vascular; Sirolimus; Tumor Suppressor Proteins; Tunica Intima; Wounds, Nonpenetrating

Topics: Angioplasty, Balloon, Coronary; Animals; Calcineurin Inhibitors; Carrier Proteins; Cell Cycle Proteins; Cell Division; Cell Movement; Clinical Trials as Topic; Clopidogrel; Coronary Artery Disease; Cyclin-Dependent Kinase Inhibitor p27; Down-Regulation; Graft Occlusion, Vascular; Humans; Hyperplasia; Macromolecular Substances; Phosphotransferases (Alcohol Group Acceptor); Platelet Aggregation Inhibitors; Signal Transduction; Sirolimus; Stents; Tacrolimus; Tacrolimus Binding Protein 1A; Ticlopidine; TOR Serine-Threonine Kinases; Tumor Suppressor Proteins; Tunica Media; Vascular Patency

The purpose of this study was to determine the efficacy of stent-based delivery of sirolimus (SRL) alone or in combination with dexamethasone (DEX) to reduce in-stent neointimal hyperplasia. SRL is a potent immunosuppressive agent that inhibits SMC proliferation by blocking cell cycle progression.. Stents were coated with a nonerodable polymer containing 185 microgram SRL, 350 microgram DEX, or 185 microgram SRL and 350 microgram DEX. Polymer biocompatibility studies in the porcine and canine models showed acceptable tissue response at 60 days. Forty-seven stents (metal, n=13; SRL, n=13; DEX, n=13; SRL and DEX, n=8) were implanted in the coronary arteries of 16 pigs. The tissue level of SRL was 97+/-13 ng/artery, with a stent content of 71+/-10 microgram at 3 days. At 7 days, proliferating cell nuclear antigen and retinoblastoma protein expression were reduced 60% and 50%, respectively, by the SRL stents. After 28 days, the mean neointimal area was 2.47+/-1.04 mm(2) for the SRL alone and 2.42+/-1.04 mm(2) for the combination of SRL and DEX compared with the metal (5.06+/-1.88 mm(2), P<0.0001) or DEX-coated stents (4.31+/-3.21 mm(2), P<0.001), resulting in a 50% reduction of percent in-stent stenosis.. Stent-based delivery of SRL via a nonerodable polymer matrix is feasible and effectively reduces in-stent neointimal hyperplasia by inhibiting cellular proliferation.

Topics: Animals; Anti-Bacterial Agents; Biocompatible Materials; Blotting, Western; Chemokine CCL2; Coronary Disease; Coronary Vessels; Dexamethasone; Disease Models, Animal; Dogs; Drug Delivery Systems; Drug Synergism; Female; Hyperplasia; Interleukin-6; Male; Polymers; Proliferating Cell Nuclear Antigen; Retinoblastoma Protein; Sirolimus; Stents; Swine; Tunica Intima

The potent immunosuppressant ascomycin (1b) was selectively alkylated at the C-32 carbinol, thus providing esters and amides of 32-ascomycinyloxyacetic acid (4, AOAA). These compounds present structural variation at the FKBP/calcineurin interface. While the native carboxylic acid 4 shows no activity in vitro, esters and simple amides of 4 exhibit potent immunosuppression in the human MLR assay. Moreover, amides show inhibitory activity in the rat popliteal lymph node hyperplasia assay. Surprisingly, FKBP binding was weakened by several orders of magnitude when secondary hydrophobic aryl amides of 4 were tested, while maintaining potent immunosuppressive efficacy in vitro.

Topics: Animals; Calcineurin; Carrier Proteins; DNA-Binding Proteins; Heat-Shock Proteins; Humans; Hyperplasia; Immunosuppressive Agents; Lymph Nodes; Lymphocyte Culture Test, Mixed; Rats; Rats, Inbred Lew; Structure-Activity Relationship; Tacrolimus; Tacrolimus Binding Proteins

Mice lacking p27(Kip1) have been created by gene targeting in embryonic stem cells. These mice are larger than the control animals, with thymus, pituitary, and adrenal glands and gonadal organs exhibiting striking enlargement. CDK2 activity is elevated about 10-fold in p27(-/-) thymocytes. Development of ovarian follicles seems to be impaired, resulting in female sterility. Similar to mice with the Rb mutation, the p27(-/-) mice often develop pituitary tumors spontaneously. The retinas of the mutant mice show a disturbed organization of the normal cellular layer pattern. These findings indicate that p27(Kip1) acts to regulate the growth of a variety of cells. Unexpectedly, the cell cycle arrest mediated by TGFbeta, rapamycin, or contact inhibition remained intact in p27(-/-) cells, suggesting that p27(Kip1) is not required in these pathways.

Topics: Animals; Base Sequence; Body Constitution; Cell Cycle; Cell Cycle Proteins; Cell Division; Cyclin-Dependent Kinase Inhibitor p27; Cyclin-Dependent Kinases; DNA Primers; DNA, Complementary; Enzyme Inhibitors; Female; Gene Expression; Gene Targeting; Genes, Tumor Suppressor; Heterozygote; Hyperplasia; Infertility, Female; Male; Mice; Mice, Knockout; Microtubule-Associated Proteins; Molecular Sequence Data; Phenotype; Pituitary Neoplasms; Polyenes; Retinal Dysplasia; Sirolimus; Tissue Distribution; Transforming Growth Factor alpha; Tumor Suppressor Proteins