BACKGROUND: Despite aggressive dietary modification, lipid lowering medications, and other medical therapy, vascular proliferative diseases continue to account for 50% of all mortality in the United States. It is a significant medical and socioeconomic problem contributing to the mortality of multiple diseases including myocardial infarction (MI), stroke, renal failure, and peripheral vascular disease. With a growing number of children becoming obese and an increase in the number of patients with co-morbidities such as metabolic syndrome and Type 2 diabetes mellitus, epidemiological studies project the morbidity and mortality of these diseases to increase. Among these vascular proliferative diseases are primary atherosclerosis, vascular restenosis, and allograft vasculopathy, all of which are the result of chronic inflammation believed to stem from initial endothelial injury. Once activated by any number of potential injurious agents, endothelial cells (ECs) secrete cytokines that act on multiple cell types. Stimulation of resident vascular smooth muscle cells (VSMCs) results in a phenotypic switch from a normally contractile state to a proliferative state. Following this phenotypic shift, VSMCs migrate from the media to the intima of the artery where they begin secretion of both pro- and anti-inflammatory cytokines. Vascular proliferative disease ensues as a result of the autocrine and paracrine signaling of these cytokines between many different cell types including ECs, VSMCs, macrophages, and T-cells. As a result of the integral role pro- and anti-inflammatory cytokines play in the development of vascular proliferative diseases, they have become the subject of intense study in the field of cardiovascular research. Interleukin-19 (IL-19) is a newly described member of the IL-10 sub-family of anti-inflammatory cytokines. Discovered in 2000, it was originally only thought to be basally expressed in monocytes and lymphocytes, however in 2005 our lab discovered that while uninjured arteries have no detectable IL-19, arteries of patients with vascular proliferative diseases have notable IL-19 expression. Since its discovery in multiple cell types of injured arteries, our lab has subsequently shown that IL-19 inhibits proliferation, migration, spreading, production of reactive oxygen species (ROSs), and expression of pro-inflammatory genes in VSMCs, while in ECs IL-19 has been shown to promote angiogenesis, proliferation, migration, and spreading. AIMS and HYPOTHESIS: The first aim of the current study is to show that IL-19 is expressed in atherosclerotic plaque, and to test that IL-19 can reduce experimental atherosclerosis in susceptible mice. The second aim of the study is to show that IL-19 can regulate development of intimal hyperplasia in a murine model of restenosis. For both aims, we sought to identify potential intracellular signaling mechanisms of IL-19 which produce the observed effect. These aims directed our overall hypothesis that the anti-inflammatory properties of IL-19 can attenuate the vascular response to injury in various animal models of vascular proliferative disease. METHODS and RESULTS: The first aim of this dissertation showed that LDLR-/- mice fed an atherogenic diet and injected with either 1.0ng/g/day or 10.0ng/g/day rmIL-19 had significantly less plaque area in the aortic arch compared with controls (p<0.0001). Weight gain and serum lipid levels were not significantly different. IL-19 could halt, but not reverse expansion of existing plaque. Gene expression in splenocytes from IL-19 treated mice demonstrated immune cell Th2 polarization, with decreased expression of T-bet, IFNgamma, IL-1β and IL-12β, and increased expression of GATA3 messenger ribonucleic acid (mRNA). A greater percentage of lymphocytes were Th2 polarized in IL-19 treated mice. Cellular characterization of plaque by immunohistochemistry demonstrated IL-19 treated mice have significantly less macrophage infiltrate compared with controls (p<0.001). Intravital microscopy revealed significantly less leukocyte adhesion in wild-type mice injected with IL-19 and fed an atherogenic diet compared with controls. Treatment of cultured EC, VSMC, and bone marrow-derived macrophages (BMDM) with IL-19 resulted in a significant decrease in chemokine mRNA, and in the mRNA-stability protein HuR. In the second aim of this dissertation we showed that IL-19 attenuates vascular restenosis in response to carotid artery ligation. Carotid artery ligation of hyper-responsive friend leukemia virus B (FVB) wild-type mice injected with 10ng/g/day rIL-19 had significantly lower neointima/media ratio (I/M) compared with phosphate buffered saline (PBS) controls (p=0.006). Conversely, carotid artery of IL-19-/- mice demonstrated significantly higher I/M ratio compared with wild-type mice (p=0.04). Importantly, the increased I/M ratio in the knockout mice could be rescued by injection of 10ng/g/day IL-19 (p=0.04). VSMC explanted from IL-19-/- mice proliferated significantly more rapidly compared with wild-type (p=0.04). Surprisingly, in this model, IL-19 does not modulate adoptive immunity. Rather, addition of IL-19 to cultured wild-type VSMC did not significantly decrease VSMC proliferation, but could rescue proliferation in IL-19-/- VSMC to wild-type levels (p=0.02). IL-19-/- VSMC expressed significantly greater levels of inflammatory mRNA including IL-1β, TNFα, and MCP-1 in response to TNFα stimulation (p<0.01 for all). No polarization of adaptive immunity was noted in these mice. CONCLUSIONS: These data are the first to report that IL-19 is a potent inhibitor of experimental atherosclerosis via diverse mechanisms including immune cell polarization, decrease in macrophage adhesion, and decrease in gene expression. In addition, these data are also the first to show that IL-19 plays a previously unrecognized protective role in vascular restenosis. Together, these data suggest IL-19 is both anti-atherogenic and anti-restenotic and may identify IL-19 as a novel therapeutic to limit vascular inflammation. / Physiology

Introdução: A reestenose pós tratamento endovascular de lesões ateroscleróticas em artérias periféricas é a principal desvantagem desta técnica minimamente invasiva. A inflamação vascular após angioplastia com balão e/ou implante de stent desempenha um papel importante na proliferação de células do músculo liso vascular e posterior crescimento de uma neoíntima, e vários marcadores inflamatórios têm sido referidos como potenciais preditores dessa complicação, porém os fatores que contribuem para a estenose intra-stent no segmento vascular periférico não foram completamente elucidados. Recentemente, tem-se sugerido que a superfície revestida de stents recobertos possa impedir a reestenose de forma mais eficaz do que os stents convencionais. Objetivo: Avaliar o papel do sistema calicreína-cinina (SCC), do óxido nítrico (NO) e das metaloproteinases (MMP), mediadores inflamatórios importantes e que contribuem ativamente para a reparação de tecidos, no processo de reestenose arterial devido a hiperplasia intimal, pós angioplastia com stent recoberto no segmento fêmoro-poplíteo, com a intenção de contribuir com novas medidas terapêuticas. Método: Foi realizado um estudo prospectivo envolvendo 27 pacientes submetidos à angioplastia com stent revestido no segmento fêmoro-poplíteo, selecionados no Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP/USP. Foram estudados os seguintes marcadores: sistema calicreína-cininas - com quantificação dos substratos (cininogênio de alto e baixo peso molecular - CAPM / CBPM) e da atividade das enzimas (calicreína plasmática e tecidual e cininase II); a determinação dos níveis de nitrito e nitratos para a avaliação de óxido nítrico; dosagem das MMPs 2 e 9 e dos níveis circulantes de seus inibidores (inibidores teciduais das metaloproteinases - TIMPs [1 e 2]). Amostras de sangue foram coletadas antes do implante do stent, 24 horas e seis meses após o procedimento. Foi realizado ultrasson Doppler após seis meses, e, na presença de alterações, realizada angiografia para comprovação da presença de reestenose. Resultados: Quatro (14,8%) dos vinte sete pacientes estudados desenvolveram reestenose (>= 50%) em seis meses. Esses pacientes tiveram níveis significativamente mais baixos de CAPM (24h, P <0,05) e de CBPM (antes - P <0,05; 24 horas P <0,01; 6 meses P <0,05); níveis mais baixos de TIMP 2 ( seis meses P<0,05) comparados ao grupo sem reestenose. As atividades da calicreína plasmática e tecidual, da cininase II, NO e MMPs tiveram comportamento semelhante entre os pacientes com e sem reestenose. Conclusão: As taxas de reestenose foram baixas com o uso de stents revestidos no segmento fêmoro-poplíteo comparativamente aos índices publicados de stents não revestidos. Os pacientes que desenvolveram reestenose mostraram níveis reduzidos de cininogênios e de TIMP-2 (seis meses após a angioplastia). Por outro lado, não foi possível demonstrar a participação do óxido nítrico e das metaloproteinases no processo de reestenose / Background: Restenosis after endovascular treatment of atherosclerotic lesions in the peripheral circulation is the major drawback of this minimally invasive technique. Vascular inflammation after balloon angioplasty or stent implantation plays an important role in smooth muscle cells proliferation and subsequent neointima growth, and various inflammatory markers have been reported as potential predictors of this complication, but the factors that contribute to the in-stent stenosis in peripheral vascular segment have not been fully elucidated. Recently, it has been suggested that the coated surface of stents grafts can prevent restenosis more effectively than conventional stents. Objective: The aim of this study was to evaluate the role of the kallikrein-kinin system (KKS), nitric oxide (NO) and metalloproteinases (MMPs), wich are important inflammatory mediators and actively contribute to tissue repair, in the process of arterial restenosis due to intimal hyperplasia, with the aim of developing new interventions. Method: Single-center prospective study with 27 patients with peripheral artery disease (PAD) requiring percutaneous transluminal angioplasty (PTA) and stenting, in the femoropopliteal segment, using coated stents grafts, was performed. The following markers were studied: kallikreinkinin system using the quantification of proteins (high and low weight Molecular kininogen HMWK / LMWK), verification of enzyme activity (tissue kallikrein, plasma kallikrein and kininase II), determination of nitrite and nitrates levels for evaluation of nitric oxide, MMPs 2 and 9 circulating levels and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs 1 and 2]). Serum samples were collected before stent implantation, 24 h and six months after the procedure. Doppler ultrasound was performed after six months, and in the presence of any changes, an angiography was performed to prove the presence of restenosis. Results: Four (14,8%) of the treated patients developed restenosis (>50%) within 6 months. These patients had significantly lower levels of HMWK (24 hours, P < .05), LMWK (before - P < .05; 24 hours - P < .01; 6 months - P < .05) and lower levels of TIMP 2 (6 months < .05) compered to no restenosis group. The activities of plasma and tissue kallikrein, kininase II, NO and MMP had similar behavior among patients with and without restenosis. Conclusion: Restenosis rates were low with the use of coated stents in the femoropopliteal segment compared to published bare metal stents results. Patients with restenosis showed reduced levels of kininogens and TIMP-2 (six months after angioplasty) in patients who developed restenosis. Moreover, it was not possible to demonstrate the involvement of nitric oxide and metalloproteinases in the restenosis process

During atherosclerosis and restenosis, there is an extensive amount of collagen synthesis and degradation. Changes in the types of collagen present can have profound effects on vascular smooth muscle cell (SMC) proliferation and migration. Type VIII collagen, which is normally present at low levels within the mature vascular system, is greatly increased during atherogenesis. The central theme of this thesis is to determine the role of type VIII collagen in the pathogenesis of atherosclerosis and restenosis. In the first study, we demonstrated the importance of type VIII collagen in SMC migration and proliferation. SMCs from type VIII collagen-deficient mice display increased adhesion and decreased spreading, migration, and proliferation compared to SMCs from wild-type mice. Treatment of SMCs from type VIII collagen-deficient mice with exogenous type VIII collagen can rescue the defects. In the second study, we determined that type VIII collagen exerts its effects through regulation of MMP-2 expression. Type VIII collagen-deficient SMCs have decreased levels of MMP-2 and are impaired in chemotaxis toward PDGF-BB and in their ability to contract thick collagen gels. We found that decreasing endogenous MMP-2 levels in normal SMCs or adding exogenous collagen to type VIII collagen-deficient SMCs is sufficient to recapitulate the type VIII collagen-deficient or wild-type SMC phenotype, respectively. In the third study, we investigated the contribution of type VIII collagen to intimal hyperplasia after mechanical injury in the mouse. We found that type VIII collagen-deficient mice display a 35% reduction in intimal hyperplasia and attenuated vessel remodeling after femoral artery wire injury, establishing a role for type VIII collagen in restenosis. The results of the work presented in this thesis demonstrate that production of type VIII collagen confers an SMC phenotype with a greater propencity for proliferation and migration. These effects are in part mediated through regulation of MMP-2 expression and activation. We conclude that the increases in type VIII collagen production that occur during atherosclerosis and restenosis contribute to the capacity of SMCs to alter the existing extracellular matrix in a manner which permits enhanced migration.

Vascular endothelial cell loss initiates directional migration of medial smooth muscle cells into the arterial intima contributing to in-stent restenosis, atherosclerosis and coronary arterial by-pass graft failure. N-cadherin is a cell-cell adhesion molecule that mediates the interaction between vascular endothelial cells and the innermost smooth muscle cells to stabilize the arterial wall. Upon injury, I reasoned that relocalization of N-cadherin on the inner most smooth muscle cells to the posterior-lateral borders stimulates cell polarization to enable directional migration. Using an in vitro scratch-wound model to stimulate cell polarity and locally remove cell-cell contacts at one pole of smooth muscle cells, I found that N-cadherin localization provides signaling cues via a Cdc42/GSK pathway that promote polarized reorganization of the cytoskeleton and directional cell migration. I also found that N-cadherin was important to functions of lamellipodia at the anterior of migrating cells. In lamellipodia, actin polymerization drives protrusion of the leading edge and coincident, but more posterior, actin depolymerization results in retrograde flow of actin and associated plasma membrane structures. Using live cell imaging, I found that clusters of N-cadherin-GFP repeatedly accumulated at the leading edge specifically at the neck of large pinocytotic vesicles called macropinosomes that were internalized and transported away from the leading edge. This localization is consistent with a role for N-cadherin in closure and scission of vesicles during macropinocytosis. These are the first studies to examine polarity in migrating vascular smooth muscle cells, and advance our understanding concerning cell-cell adhesions in controlling directional cell migration. My results suggest that N-cadherin may serve as a viable target for the treatment of arterial stenosis that would limit smooth muscle cell migration and stabilize the arterial wall. Furthermore, I report on a novel localization and function of N-cadherin in the biogenesis of macropinosomes in the lamellipodia that contribute to cell protrusion.

Vascular endothelial cell loss initiates directional migration of medial smooth muscle cells into the arterial intima contributing to in-stent restenosis, atherosclerosis and coronary arterial by-pass graft failure. N-cadherin is a cell-cell adhesion molecule that mediates the interaction between vascular endothelial cells and the innermost smooth muscle cells to stabilize the arterial wall. Upon injury, I reasoned that relocalization of N-cadherin on the inner most smooth muscle cells to the posterior-lateral borders stimulates cell polarization to enable directional migration. Using an in vitro scratch-wound model to stimulate cell polarity and locally remove cell-cell contacts at one pole of smooth muscle cells, I found that N-cadherin localization provides signaling cues via a Cdc42/GSK pathway that promote polarized reorganization of the cytoskeleton and directional cell migration. I also found that N-cadherin was important to functions of lamellipodia at the anterior of migrating cells. In lamellipodia, actin polymerization drives protrusion of the leading edge and coincident, but more posterior, actin depolymerization results in retrograde flow of actin and associated plasma membrane structures. Using live cell imaging, I found that clusters of N-cadherin-GFP repeatedly accumulated at the leading edge specifically at the neck of large pinocytotic vesicles called macropinosomes that were internalized and transported away from the leading edge. This localization is consistent with a role for N-cadherin in closure and scission of vesicles during macropinocytosis. These are the first studies to examine polarity in migrating vascular smooth muscle cells, and advance our understanding concerning cell-cell adhesions in controlling directional cell migration. My results suggest that N-cadherin may serve as a viable target for the treatment of arterial stenosis that would limit smooth muscle cell migration and stabilize the arterial wall. Furthermore, I report on a novel localization and function of N-cadherin in the biogenesis of macropinosomes in the lamellipodia that contribute to cell protrusion.

During atherosclerosis and restenosis, there is an extensive amount of collagen synthesis and degradation. Changes in the types of collagen present can have profound effects on vascular smooth muscle cell (SMC) proliferation and migration. Type VIII collagen, which is normally present at low levels within the mature vascular system, is greatly increased during atherogenesis. The central theme of this thesis is to determine the role of type VIII collagen in the pathogenesis of atherosclerosis and restenosis. In the first study, we demonstrated the importance of type VIII collagen in SMC migration and proliferation. SMCs from type VIII collagen-deficient mice display increased adhesion and decreased spreading, migration, and proliferation compared to SMCs from wild-type mice. Treatment of SMCs from type VIII collagen-deficient mice with exogenous type VIII collagen can rescue the defects. In the second study, we determined that type VIII collagen exerts its effects through regulation of MMP-2 expression. Type VIII collagen-deficient SMCs have decreased levels of MMP-2 and are impaired in chemotaxis toward PDGF-BB and in their ability to contract thick collagen gels. We found that decreasing endogenous MMP-2 levels in normal SMCs or adding exogenous collagen to type VIII collagen-deficient SMCs is sufficient to recapitulate the type VIII collagen-deficient or wild-type SMC phenotype, respectively. In the third study, we investigated the contribution of type VIII collagen to intimal hyperplasia after mechanical injury in the mouse. We found that type VIII collagen-deficient mice display a 35% reduction in intimal hyperplasia and attenuated vessel remodeling after femoral artery wire injury, establishing a role for type VIII collagen in restenosis. The results of the work presented in this thesis demonstrate that production of type VIII collagen confers an SMC phenotype with a greater propencity for proliferation and migration. These effects are in part mediated through regulation of MMP-2 expression and activation. We conclude that the increases in type VIII collagen production that occur during atherosclerosis and restenosis contribute to the capacity of SMCs to alter the existing extracellular matrix in a manner which permits enhanced migration.

<p>Covering the metal surface of blood-contacting cardiovascular implants (stents, ventricular assist devices) with functional endothelium may reduce the incidence of clotting and restenosis complications and also reduce the need for risky anticoagulation therapy following implantation of such devices. We developed a novel cell therapy for seeding autologous endothelium onto blood-contacting vascular stents at the point of care to reduce thrombosis and stent restenosis. The proposed research tested the following hypotheses: (1) autologous endothelial cells (ECs) can spread on titanium (Ti) tubes and reduce thrombosis on the Ti surface <italic>in vivo</italic>; (2) shear stresses on the surfaces of an implanted carotid artery stent will be conducive to EC retention and function under arterial flow; and (3) nitinol stents seeded with ECs at the point of care will remain adherent and functional after stent deployment and arterial fluid shear stress conditions <italic>in vitro</italic> and <italic>in vivo</italic>. Based on the experiments reported herein, the primary conclusions of the dissertation are as follows: (1) autologous ECs significantly reduce thrombosis on Ti surfaces implanted into the bloodstream <italic>in vivo</italic>; (2) shear stresses on stent surfaces under carotid artery flow conditions are sufficiently low to be compatible with EC retention and function; (3) ECs seeded onto nitinol stents by infusion at the point of care are retained and spread to form a functional layer following deployment and arterial flow conditions both <italic>in vitro</italic> and <italic>in vivo</italic>.</p> / Dissertation

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

The detection of in-stent restenosis is important in clinical practice by providing useful information to guide therapy. The objectives of this study were to evaluate the effectiveness of the exercise test (ET) in the detection of restenosis after percutaneous transluminal coronary angioplasty with stent conventional implantation (Stent-ATC) and, as a gold standard, coronary angiography. We studied 25 asymptomatic patients, aged between 44 and 83 years, who underwent PTCA-Stent for at least six months. The patients underwent TE employing the Bruce protocol. The positivity criteria for ischemia was ST segment depression > 1mm, measured at the J point and with horizontal or descending. The results obtained in TE were compared with those of coronary angiography is considered the in-stent restenosis lesions with obstruction > 50%. We estimated the sensitivity and specificity and positive predictive value and negative procedure. Of the individuals studied, 10 (40%) had in-stent restenosis by angiographic criteria, and only 3 (12%) had positive TST tests for ischemia. The relationship between the TE and coronary angiography was not significant (p = 0.315), indicating that the tests are independent. The concordance between the diagnoses was low (Kappa coefficient: 0.151), the same occurring with the sensitivity (20%). The specificity of the test was high (93%) and positive predictive value 65.56% and negative predictive value 63.63%. The overall efficiency of the test is estimated with accuracy low 63.98%. We conclude that the TE has low sensitivity and high specificity in detecting in-stent restenosis in asymptomatic patients. The overall efficiency of ET is low. / A detecção da reestenose intrastent é importante na prática clínica fornecendo informações úteis para a orientação terapêutica. Os objetivos deste estudo foram, avaliar a eficácia do teste ergométrico (TE) na detecção de reestenose após angioplastia transluminal coronariana com implante de stent convencional (ATC-stent), comparando este método com os resultados obtidos com a cineangiocoronariografia. Foram estudados 25 pacientes assintomáticos, com idade entre 44 e 83 anos, que realizaram ATC-stent há, no mínimo, seis meses e no máximo um ano. Os pacientes foram submetidos ao TE empregando-se o protocolo de Bruce. O critério de positividade para isquemia foi o infra-desnivelamento do segmento ST > 1mm, aferido no ponto J e com morfologia horizontal ou descendente. Os resultados obtidos no TE foram comparados com aqueles da cineangiocoronariografia sendo considerada como reestenose intrastent a presença de lesões com obstrução >50%. Foram estimadas a sensibilidade e especificidade e o valor preditivo positivo e negativo do procedimento. Dos indivíduos estudados, 10 (40%) apresentaram reestenose intrastent pelo critério angiográfico e apenas 3 (12%) tiveram TE positivo para isquemia. A relação entre o TE e a cineangiocoronariografia não foi significativa (p=0,315), indicando que os testes são independentes. A concordância entre os diagnósticos foi baixa (coeficiente Kappa: 0,151), o mesmo ocorrendo com a sensibilidade (20%). A especificidade do TE foi elevada (93%), sendo o valor preditivo positivo 65,56% e o valor preditivo negativo 63,63%. A eficiência global do teste é baixa com acurácia estimada em 63,98%. Em conclusão, nas condições estudadas o TE tem baixa sensibilidade e alta especificidade na detecção de reestenose intrastent em pacientes assintomáticos. A eficiência global do TE é baixa. / Mestre em Ciências da Saúde

Introdução: A reestenose pós tratamento endovascular de lesões ateroscleróticas em artérias periféricas é a principal desvantagem desta técnica minimamente invasiva. A inflamação vascular após angioplastia com balão e/ou implante de stent desempenha um papel importante na proliferação de células do músculo liso vascular e posterior crescimento de uma neoíntima, e vários marcadores inflamatórios têm sido referidos como potenciais preditores dessa complicação, porém os fatores que contribuem para a estenose intra-stent no segmento vascular periférico não foram completamente elucidados. Recentemente, tem-se sugerido que a superfície revestida de stents recobertos possa impedir a reestenose de forma mais eficaz do que os stents convencionais. Objetivo: Avaliar o papel do sistema calicreína-cinina (SCC), do óxido nítrico (NO) e das metaloproteinases (MMP), mediadores inflamatórios importantes e que contribuem ativamente para a reparação de tecidos, no processo de reestenose arterial devido a hiperplasia intimal, pós angioplastia com stent recoberto no segmento fêmoro-poplíteo, com a intenção de contribuir com novas medidas terapêuticas. Método: Foi realizado um estudo prospectivo envolvendo 27 pacientes submetidos à angioplastia com stent revestido no segmento fêmoro-poplíteo, selecionados no Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP/USP. Foram estudados os seguintes marcadores: sistema calicreína-cininas - com quantificação dos substratos (cininogênio de alto e baixo peso molecular - CAPM / CBPM) e da atividade das enzimas (calicreína plasmática e tecidual e cininase II); a determinação dos níveis de nitrito e nitratos para a avaliação de óxido nítrico; dosagem das MMPs 2 e 9 e dos níveis circulantes de seus inibidores (inibidores teciduais das metaloproteinases - TIMPs [1 e 2]). Amostras de sangue foram coletadas antes do implante do stent, 24 horas e seis meses após o procedimento. Foi realizado ultrasson Doppler após seis meses, e, na presença de alterações, realizada angiografia para comprovação da presença de reestenose. Resultados: Quatro (14,8%) dos vinte sete pacientes estudados desenvolveram reestenose (>= 50%) em seis meses. Esses pacientes tiveram níveis significativamente mais baixos de CAPM (24h, P <0,05) e de CBPM (antes - P <0,05; 24 horas P <0,01; 6 meses P <0,05); níveis mais baixos de TIMP 2 ( seis meses P<0,05) comparados ao grupo sem reestenose. As atividades da calicreína plasmática e tecidual, da cininase II, NO e MMPs tiveram comportamento semelhante entre os pacientes com e sem reestenose. Conclusão: As taxas de reestenose foram baixas com o uso de stents revestidos no segmento fêmoro-poplíteo comparativamente aos índices publicados de stents não revestidos. Os pacientes que desenvolveram reestenose mostraram níveis reduzidos de cininogênios e de TIMP-2 (seis meses após a angioplastia). Por outro lado, não foi possível demonstrar a participação do óxido nítrico e das metaloproteinases no processo de reestenose / Background: Restenosis after endovascular treatment of atherosclerotic lesions in the peripheral circulation is the major drawback of this minimally invasive technique. Vascular inflammation after balloon angioplasty or stent implantation plays an important role in smooth muscle cells proliferation and subsequent neointima growth, and various inflammatory markers have been reported as potential predictors of this complication, but the factors that contribute to the in-stent stenosis in peripheral vascular segment have not been fully elucidated. Recently, it has been suggested that the coated surface of stents grafts can prevent restenosis more effectively than conventional stents. Objective: The aim of this study was to evaluate the role of the kallikrein-kinin system (KKS), nitric oxide (NO) and metalloproteinases (MMPs), wich are important inflammatory mediators and actively contribute to tissue repair, in the process of arterial restenosis due to intimal hyperplasia, with the aim of developing new interventions. Method: Single-center prospective study with 27 patients with peripheral artery disease (PAD) requiring percutaneous transluminal angioplasty (PTA) and stenting, in the femoropopliteal segment, using coated stents grafts, was performed. The following markers were studied: kallikreinkinin system using the quantification of proteins (high and low weight Molecular kininogen HMWK / LMWK), verification of enzyme activity (tissue kallikrein, plasma kallikrein and kininase II), determination of nitrite and nitrates levels for evaluation of nitric oxide, MMPs 2 and 9 circulating levels and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs 1 and 2]). Serum samples were collected before stent implantation, 24 h and six months after the procedure. Doppler ultrasound was performed after six months, and in the presence of any changes, an angiography was performed to prove the presence of restenosis. Results: Four (14,8%) of the treated patients developed restenosis (>50%) within 6 months. These patients had significantly lower levels of HMWK (24 hours, P < .05), LMWK (before - P < .05; 24 hours - P < .01; 6 months - P < .05) and lower levels of TIMP 2 (6 months < .05) compered to no restenosis group. The activities of plasma and tissue kallikrein, kininase II, NO and MMP had similar behavior among patients with and without restenosis. Conclusion: Restenosis rates were low with the use of coated stents in the femoropopliteal segment compared to published bare metal stents results. Patients with restenosis showed reduced levels of kininogens and TIMP-2 (six months after angioplasty) in patients who developed restenosis. Moreover, it was not possible to demonstrate the involvement of nitric oxide and metalloproteinases in the restenosis process