umirolimus and Inflammation

Biodegradable polymer-based drug-eluting stents are thought to be safer than durable polymer-based stents. However, the long-term vascular response remains unclear. The aim of this study was to compare the biocompatibility of durable polymer-based sirolimus-eluting (SES) and everolimus-eluting (EES) stents with biodegradable polymer-based biolimus-eluting (BES) stents in a porcine coronary model. Stents were implanted in porcine coronaries. Acetylcholine challenge tests and optical coherence tomography (OCT) examination were performed at one month. Animals were sacrificed at three and six months (n=6 each), and the stents were analysed histologically. At one month, acetylcholine challenge tests revealed a trend towards greatest vasoconstriction in SES, less in BES, and least in EES, but the differences were not significant. OCT analysis demonstrated the highest incidence of uncovered struts in SES, followed by BES, while EES showed almost complete strut coverage (41.7±27.0%, 24.5±23.8%, 0.4±0.8%, respectively; p=0.004). Upon histological analysis at three months, SES showed a significantly higher inflammatory score than BES and EES (2.9±1.4, 0.8±0.9, 0.5±0.4, respectively; p=0.001), and this was maintained at six months (1.6±1.5, 0.3±0.3, 0.4±0.6, respectively; p=0.049). While SES showed an increased inflammatory reaction, EES and BES showed minimal inflammation. These results indicate that the late inflammatory reaction does not necessarily depend on degradability of the polymer, if the combination of the drug, metal, and polymer is biocompatible.

Topics: Absorbable Implants; Acetylcholine; Animals; Coated Materials, Biocompatible; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Everolimus; Inflammation; Materials Testing; Models, Animal; Neointima; Polymers; Sirolimus; Swine; Tomography, Optical Coherence; Vasodilator Agents

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 current study sought to examine inflammation at the stented segments of Nobori (Terumo Corporation, Tokyo, Japan) and Cypher (Cordis, Miami, Florida) drug-eluting stents (DES), as well as free radical production and endothelial function of the adjacent nonstented segments in a pig coronary model.. Nobori is a novel DES, incorporating a biolimus A9-eluting biodegradable polymer coated only on the abluminal surface of the stent. These unique features may favorably affect inflammation and endothelial function, as compared to the currently marketed DES. Presently, pre-clinical data on direct comparison of the various generations of DES are not available.. A total of 18 DES were implanted in pig coronary arteries and subsequently explanted at 1 month. Stented segments were assessed by angiography and histology. Ex vivo vasomotor function and superoxide production in segments proximal and distal to the stent were determined. The vasoconstriction, endothelial-dependent relaxation, and endothelial-independent relaxation of proximal and distal nonstented segments were measured.. Histological evaluation revealed lower inflammatory response with Nobori than with Cypher DES. There is trend for lower angiographic percentage diameter stenosis in Nobori versus Cypher groups (p = 0.054). There was increased endothelium-dependent relaxation, decreased endothelin-1-mediated contraction, and less superoxide production in the vessel segments proximal and distal to Nobori versus Cypher stents.. Our data show significantly lower inflammatory response in the stented segments, and rapid recovery of endothelial function of peristent segments in the Nobori group compared with Cypher DES group at 1 month in porcine coronary artery model.

Topics: Angioplasty, Balloon, Coronary; Animals; Cardiovascular Agents; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Dose-Response Relationship, Drug; Drug-Eluting Stents; Endothelium, Vascular; Inflammation; Japan; Models, Animal; Prosthesis Design; Recovery of Function; Sirolimus; Superoxides; Sus scrofa; Time Factors; Vasoconstriction; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents

The time-dependent changes in endothelial and healing properties of coronary arteries implanted with a biodegradable polymer-based biolimus A9-eluting stent (BioPol-BES) have not been investigated. We evaluated the short-term and the long-term in vivo response of BioPol-BES, as compared to a permanent polymer-based sirolimus-eluting stent (PermPol-SES), and a bare metal stent (BMS).. Overlapping stents were placed in 33 swine (n=11 for BES, SES, and BMS, respectively) for two and four weeks and single stents in 30 miniature pigs (n=18 for BES, n=9 for SES, n=3 for BMS) for three, nine and 15-month evaluations. The vessel patency, arterial healing and endothelialisation were assessed by angiography, histopathology and scanning electron microscopy. At four weeks, the endothelialisation at overlapping stent regions was greater with BioPol-BES (87.8±3.7%) and BMSs (98.0±0.4%) than with PermPol-SES (66.4±3.2%). The inflammation score in vessels implanted with single BioPol-BES increased slightly from three to 15 months (0.00±0.00 to 0.28±0.14), while this increase was more pronounced with PermPol-SES (0.11±0.07 to 1.56±0.68). Compared to BMS moderate lymphocyte infiltration was seen with BioPol-BES, and marked granulomatous formation with PermPol-SES.. The level of endothelial coverage in BioPol-BES was comparable to BMS at four weeks, with no significant increase of inflammatory reaction up to 15 months.

Topics: Angioplasty, Balloon; Animals; Cardiovascular Agents; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Endothelial Cells; Granuloma; Inflammation; Lactic Acid; Lymphocytes; Metals; Microscopy, Electron, Scanning; Models, Animal; Polyesters; Polymers; Prosthesis Design; Sirolimus; Swine; Swine, Miniature; Time Factors; Ultrasonography; Vascular Patency; Wound Healing

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