cyclic-gmp and Carotid-Stenosis

Long-term results of surgical vessel reconstruction are compromised by restenosis caused by neointimal hyperplasia. Recent studies suggest that reduced cyclic guanosine monophosphate signaling is associated with neointima formation. In a rat model of endarterectomy, we investigated the effect of pharmacologic inhibition of cyclic guanosine monophosphate degradation on neointima formation by using the selective phosphodiesterase-5 inhibitor vardenafil.. Carotid endarterectomy was performed in male Sprague-Dawley rats by means of incision of the right common carotid artery with removal of intima. Four groups were studied: unoperated control rats (n = 4), sham-operated rats (n = 9), control rats with endarterectomy (n = 9), or endarterectomized rats treated with vardenafil (10 mg/kg/day) postoperatively (n = 9). After 3 weeks, vessel compartment areas were measured by means of conventional microscopy with hematoxylin and eosin staining. Immunohistochemical analysis was performed to confirm neointima formation and the local cyclic guanosine monophosphate content. Plasma levels of cyclic guanosine monophosphate were determined by means of enzyme immunoassay. Student's t test was used for statistical evaluation.. Immunohistochemical analysis demonstrated intensive staining for transforming growth factor beta1 and alpha-smooth muscle actin in the control neointima. Vardenafil significantly reduced the stenosis grade (24.64% +/- 7.46% vs 54.12% +/- 10.30% in the control group, P < .05) and expression of transforming growth factor beta1, as well as alpha-smooth muscle actin, in the neointima. The immunohistochemical score for cyclic guanosine monophosphate was higher in the treated neointima (4.80 +/- 0.76 vs 2.84 +/- 0.40 in the control group, P < .05), and increased plasma cyclic guanosine monophosphate levels were found by means of enzyme immunoassay as well (84.65 +/- 12.77 pmol/mL vs 43.50 +/- 3.30 pmol/mL in the control group, P < .05).. Treatment with vardenafil can be considered a new possibility to prevent neointimal hyperplasia after endarterectomy.

Topics: Actins; Animals; Carotid Artery, Common; Carotid Stenosis; Cyclic GMP; Endarterectomy, Carotid; Hyperplasia; Imidazoles; Immunohistochemistry; Male; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Rats; Rats, Sprague-Dawley; Recurrence; Sulfones; Transforming Growth Factor beta1; Triazines; Tunica Intima; Vardenafil Dihydrochloride

Topics: Animals; Carotid Artery Injuries; Carotid Stenosis; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Cyclic GMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 5; Disease Models, Animal; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Purines; Recurrence; Signal Transduction; Sildenafil Citrate; Sulfones; Vasodilation

Nitric oxide (NO) is of crucial importance for smooth muscle cell (SMC) function and exerts numerous, and sometimes opposing, effects on vascular restenosis. Although cGMP-dependent protein kinase type I (cGKI) is a principal effector of NO, the molecular pathway of vascular NO signaling in restenosis is unclear. The purpose of this study was to examine the functional role of the smooth muscle cGMP/cGKI signaling cascade in restenosis of vessels.. Tissue-specific mouse mutants were generated in which the cGKI protein was ablated in SMCs. We investigated whether the absence of cGKI in SMCs would affect vascular remodeling after carotid ligation or removal of the endothelium. No differences were detected between the tissue-specific cGKI mutants and control mice at different time points after vascular injury on a normolipidemic or apoE-deficient background. In line with these results, chronic drug treatment of injured control mice with the phosphodiesterase-5 inhibitor sildenafil elevated cGMP levels but had no influence on the ligation-induced remodeling.. The genetic and pharmacological manipulation of the cGMP/cGKI signaling indicates that this pathway is not involved in the protective effects of NO, suggesting that NO affects vascular remodeling during restenosis via alternative mechanisms.

Topics: Animals; Apolipoproteins E; Carotid Artery Injuries; Carotid Artery, Common; Carotid Stenosis; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Cyclic GMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 5; Disease Models, Animal; Ligation; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Purines; Recurrence; Signal Transduction; Sildenafil Citrate; Sulfones; Time Factors

Hemoglobin-based oxygen carriers (HBOCs) have been developed primarily for their oxygenating function and possible use as an alternative to red blood cells during surgery or after major trauma. However, their effect on hemostasis has not been studied extensively. We compared the effects on hemostasis of bovine-derived hemoglobin solution (HBOC-201) with gelatin solution and saline infusion in an experimental model of arterial thrombosis and bleeding. After anesthesia, the Folts model was constructed in 30 rabbits. The common carotid artery was exposed, and a 60% stenosis was induced. A compression injury of the artery was then produced, which triggered a series of cyclic episodes of thrombosis (cyclic flow reductions [CFRs]). After the number of baseline CFRs was counted, animals were assigned randomly to one of three groups (n = 10 each): saline (control), gelatin, or HBOC-201 solution. The effect of studied solutions was observed by recording the number of CFRs during another period and was compared with that of saline. Ear immersion bleeding time was recorded after each CFR period. Gelatin and HBOC-201 had similar effects, manifested by significantly decreased CFRs (from median of 7 to 1 and 6 to 1, respectively) and significantly lengthened bleeding time (from 88 to 98 s and 81 to 102 s, respectively; P < 0.05). Saline infusion had no significant effect on CFRs or bleeding time. HBOC-201 and gelatin had similar effects marked by a reduction in the arterial thrombosis rate and increased bleeding time in rabbits.. In a rabbit thrombosis and hemorrhagic model, a polymerized bovine-derived hemoglobin solution and a gelatin solution infusion decreased arterial thrombosis and lengthened bleeding time.

Topics: Animals; Bleeding Time; Blood Platelets; Blood Substitutes; Carotid Arteries; Carotid Artery Thrombosis; Carotid Stenosis; Cattle; Chemistry, Pharmaceutical; Cyclic GMP; Gelatin; Hemodynamics; Hemorrhage; Hemostasis; Male; Platelet Aggregation; Rabbits

Adrenomedullin (AM) is a potent vasodilator expressed in tissues relevant to cardiovascular function. AM peptide has been shown to inhibit the proliferation and migration of vascular smooth muscle cells in vitro. However, the effect of AM on blood vessels after vascular injury in vivo has not been elucidated. In order to explore the potential roles of AM in vascular biology, we evaluated the effect of AM by local gene delivery on neointima formation in balloon-injured rat artery. Adenovirus carrying the human AM cDNA under the control of cytomegalovirus promoter/enhancer (Ad.CMV-hAM) was generated by homologous recombination. After delivery of Ad.CMV-hAM into rat left carotid artery, we identified the expression of human AM mRNA in the left carotid artery, but not in the right carotid artery, heart or kidney by reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern blot analysis. Following local AM gene delivery, we observed a 51% reduction in intima/media ratio at the injured site as compared with that of control rats injected with the luciferase gene (n=7, P<0.01). AM gene transfer resulted in regeneration of endothelium as compared to the control. AM gene delivery significantly increased cGMP levels in balloon-injured arteries. These results indicate that AM contributes to reduction of neointima formation by promotion of re-endothelialization and inhibition of vascular smooth muscle cell proliferation via cGMP-dependent signaling pathway.

Topics: Adenoviridae; Adrenomedullin; Angioplasty, Balloon; Animals; Arterial Occlusive Diseases; Carotid Arteries; Carotid Stenosis; Cyclic AMP; Cyclic GMP; Gene Expression; Genetic Vectors; Humans; Models, Biological; Peptides; Rats; RNA, Messenger; Tunica Intima

Long-term intravenous infusion of high-dose C-type natriuretic peptide (CNP) is known to prevent neointimal formation after vascular injury. Ultrasound (US) irradiation during microbubbles (MBs) infusion (US/MBs) has been used for local delivery of bioactive agents. We examined whether short-term infusion of CNP could also inhibit neointimal development and whether combined US/MBs treatment at the beginning of the CNP infusion could enhance its effect.. In the rat carotid artery-balloon injury model, the intima/media area (I/M) ratio 14 days after injury was compared among various short-term post-injury treatments. For combined US/MBs, a commercial echocardiograph (1.8 MHz, mechanical index 1.0) and albumin-coated octafluoropropane gas MBs were used.. Infusion of high-dose CNP (1.0 microg/kg/min) immediately after injury for only 24 h successfully reduced the I/M ratio (0.18+/-0.05) to 18% of the ratio in control rats (1.00+/-0.13) that underwent only balloon injury. Although low-dose CNP (0.1 microg/kg/min for 24 h) alone was not effective in reducing the I/M ratio (0.83+/-0.18), combined US/MBs treatment for the first 80 min of the infusion markedly reduced the I/M ratio (0.17+/-0.07), which persisted until 28 days after injury (0.16+/-0.04).. The effects of CNP on the events occurring early after arterial injury may be important in preventing subsequent neointimal development. Thus, intravenous infusion of CNP with US/MBs at its initiation may provide a clinically feasible anti-restenosis therapy applicable immediately after vascular interventions.

Topics: Analysis of Variance; Animals; Carotid Artery Injuries; Carotid Stenosis; Catheter Ablation; Combined Modality Therapy; Cyclic GMP; Male; Natriuretic Peptide, C-Type; Rats; Rats, Sprague-Dawley; Tunica Intima; Ultrasonic Therapy; Ultrasonography

YC-1, a synthetic benzyl indazole derivative, is capable of stimulating endogenous vessel wall cyclic guanosine monophosphate (cGMP) production and attenuating the remodeling response to experimental arterial angioplasty. In an effort to investigate the mechanisms of this YC-1-mediated vasoprotection, we examined the influence of soluble YC-1 or YC-1 incorporated in a polyethylene glycol (PEG) hydrogel on cultured rat vascular smooth muscle cell (SMC) cGMP synthesis, SMC proliferation, and platelet function. Results demonstrate that soluble YC-1 stimulated SMC cGMP production in a dose-dependent fashion, while both soluble and hydrogel-released YC-1 inhibited vascular SMC proliferation in a dose-dependent fashion without effects on cell viability. Platelet aggregation and adherence to collagen were both significantly inhibited in a dose-dependent fashion by soluble and hydrogel-released YC-1. Arterial neointima formation following experimental balloon injury was significantly attenuated by perivascular hydrogel-released YC-1. These results suggest that YC-1 is a potent, physiologically active agent with major anti-proliferative and anti-platelet properties that may provide protection against vascular injury through cGMP-dependent mechanisms.

Topics: Angioplasty, Balloon; Animals; Arterial Occlusive Diseases; Blood Platelets; Carotid Stenosis; Cell Adhesion; Cell Division; Cells, Cultured; Cyclic GMP; Dose-Response Relationship, Drug; Hydrogels; Indazoles; Muscle, Smooth, Vascular; Platelet Aggregation Inhibitors; Polyethylene Glycols; Rats; Rats, Sprague-Dawley

The pathobiologic process of arterial stenosis following balloon angioplasty continues to be an enigmatic problem in clinical settings. This research project investigates the ability of YC-1, a benzyl indazole derivative that sensitizes sGC/cGMP, to stimulate endogenous cGMP and attenuate balloon injury-induced neointima (NI) formation in the rat carotid artery. Northern and Western blot analyses revealed enhanced acute expression of iNOS and inducible heme oxygenase (HO-1) mRNA and protein in the injured artery. The contralateral uninjured artery also demonstrated acute HO-1 mRNA and protein induction without detectable iNOS expression. Perivascular application of YC-1 immediately following injury significantly stimulated acute vessel wall cGMP compared to untreated controls. YC-1 treated sections demonstrated significant reduction in NI area (-74%), NI area/medial wall area (-72%), and NI thickness (-76%) 2 weeks post-injury. These results directly implicate YC-1 as a potent new therapeutic agent capable of reducing post-angioplasty stenosis through endogenous CO- and/or NO-mediated, cGMP-dependent processes.

Topics: Angioplasty, Balloon; Animals; Carotid Arteries; Carotid Artery Injuries; Carotid Stenosis; Cyclic GMP; Gene Expression Regulation, Enzymologic; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Indazoles; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Platelet Aggregation Inhibitors; Rats; Rats, Sprague-Dawley; Recurrence; RNA, Messenger; Transcription, Genetic; Tunica Intima

To clarify relationships between the (endothelial vasodilatory and vasoconstrictive function) and leukocyte inflammatory mediators in subjects with asymptomatic atherosclerosis, we measured (intraplatelet cyclic 3',5'-guanosine monophosphate [cGMP] and cyclic 3',5'-adenosine monophosphate [cAMP]), plasma endothelin (ET-1), and plasma neopterin in 197 subjects with asymptomatic atherosclerosis (median age 63 years, range 49-69 years). We measured neutrophil protease 4 (NP4), tumor necrosis factor (TNFmu), soluble tumor necrosis factor receptor-1 (sTNFR-1), and neutrophil gelatinase associated lipocalin (NGAL) in 152 of the 197 subjects. Intraplatelet cGMP correlated inversely with plasma ET-1 (r=-0.22; p=0.01), which confirms earlier in vitro data of the inhibitory effect of ET-1 on NO production and/or the cGMP mediated inhibitory effect of NO on ET-1 production. Plasma neopterin as well as NP4 correlated directly with intraplatelet cGMP (r=0.24; p<0.01 and r=0.33; p<0.001, respectively). Intraplatelet cAMP correlated directly with plasma TNFmu (r=0.17; p<0.05) and sTNFR-1 (r=0.20; p<0.05). The relationship between leukocyte derived inflammatory mediators and intraplatelet cyclic nucleotides suggest an antiaggregating effect of leukocytes upon platelets, which may constitute a negative feedback mechanism that inhibits platelet activation during the atherosclerotic inflammatory process.

Topics: Aged; Arteriosclerosis; Blood Platelets; Carotid Artery, Common; Carotid Stenosis; Cyclic AMP; Cyclic GMP; Cytokines; Endothelin-1; Female; Humans; Inflammation; Leukocytes; Male; Middle Aged; Myeloblastin; Neopterin; Platelet Aggregation; Prospective Studies; Risk Factors; Serine Endopeptidases; Ultrasonography

Topics: Animals; Biological Assay; Carotid Stenosis; Cell Line; Cerebral Infarction; Cyclic GMP; Female; Fibroblasts; Humans; Ischemic Attack, Transient; Male; Middle Aged; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Nitric Oxide; Rats