Stent-Based Gene Delivery for Coronary Disease.

Percutaneous coronary interventions (PCI) are the mainstay for treatment of advanced coronary disease. A majority of PCI involve deployment of a stent in the affected vascular segment. This chapter introduces the concept of using stents as a platform for delivering gene therapies to the vasculature with the overarching aim of mitigating in-stent restenosis (ISR), late stent thrombosis (LST), and neoatherosclerosis (NA), a triad of delayed complications that reduce the overall success rate of PCI. The chapter provides a detailed methodology for coatless reversible attachment of adenoviral (Ad) and adeno-associated viral (AAV) vectors to the metal stent struts along with representative in vitro and in vivo results.

ADA gene haplotype is associated with coronary-in-stent-restenosis.

BACKGROUND: Cardiovascular diseases (CVDs) are the most common and the first cause of death worldwide. While some studies have investigated the association of the Adenosine Deaminase (ADA) gene with CDVs, its roles on in-stent restenosis (ISR) has not been studied. METHODS AND RESULTS: In this study, we investigated the role of ADA gene variants in both genetic and haplotype models on the risk of ISR. 91 samples were included in this study. The subjects were divided into two groups regarding having or not-having ISR (n = 40 ISR+ and n = 51 ISR-). The genotyping for G22A (rs73598374) and A4223C (rs452159) polymorphisms was performed using PCR-RFLP method. Statistical analysis was performed by SPSS v. 20 and Haploview 4.2 softwares. The basic demographic conditions in ISR groups were statistically similar. There was a significant association between A allele of rs452159 ISR groups after adjustment (allelic model: P value = 0.028, OR(95%CI) = 0.366(0.149-0.899)), while rs73598374 polymorphism shows no significant association with ISR. In haplotype analysis, the GA (G:rs73598374/A:rs452159) haplotype decreased the risk of ISR (P value = 00.025, OR(95%CI) = 0.382(0.161-0.907)). CONCLUSIONS: This study suggests that A allele of ADA rs452159 polymorphism and GA (G:rs73598374/A:rs452159) haplotype may be related to decreased risk of ISR in CAD patients receiving drug-eluting stent and offers more observational studies on ADA variants in other populations to generate a potential haplotype panel for ISR risk assessment.

Circulating microRNA-21 as Stable Blood-Based Markers for Patients With ISR After PCI.

It recently has been reported that the in-stent restenosis (ISR) of expanded area after percutaneous coronary intervention (PCI) within six months can become a serious postoperative complication. A real-time quantitative PCR was used to analyze the expression of serum miR-21 in 33 ISR and 37 non-ISR patients after PCI. Expression of miR-21 was significantly higher in the ISR group compared with that in the NISR group, and a similar trend also occurred in factor- (TNF-α) level, Interleukin -6 (IL-6) level, and plaque area (PLA). However, a contrary trend occurred in the external elastic membrane area (EEM) and minimal lumen area (MLA). This study suggests that the increased expression of serum miR-21 is related to ISR after PCI, and miR-21 can be a new predictor of ISR.

Myostatin Inhibits Vascular Smooth Muscle Cell Proliferation and Local 14q32 microRNA Expression, But Not Systemic Inflammation or Restenosis.

Myostatin is a negative regulator of muscle cell growth and proliferation. Furthermore, myostatin directly affects the expression of 14q32 microRNAs by binding the 14q32 locus. Direct inhibition of 14q32 microRNA miR-495-3p decreased postinterventional restenosis via inhibition of both vascular smooth muscle cell (VSMC) proliferation and local inflammation. Here, we aimed to investigate the effects of myostatin in a mouse model for postinterventional restenosis. In VSMCs in vitro, myostatin led to the dose-specific downregulation of 14q32 microRNAs miR-433-3p, miR-494-3p, and miR-495-3p. VSMC proliferation was inhibited, where cell migration and viability remained unaffected. In a murine postinterventional restenosis model, myostatin infusion did not decrease restenosis, neointimal area, or lumen stenosis. Myostatin inhibited expression of both proliferation marker PCNA and of 14q32 microRNAs miR-433-3p, miR-494-3p, and miR-495-3p dose-specifically in cuffed femoral arteries. However, 14q32 microRNA expression remained unaffected in macrophages and macrophage activation as well as macrophage influx into lesions were not decreased. In conclusion, myostatin did not affect postinterventional restenosis. Although myostatin inhibits 14q32 microRNA expression and proliferation in VSMCs, myostatin had no effect on macrophage activation and infiltration. Our findings underline that restenosis is driven by both VSMC proliferation and local inflammation. Targeting only one of these components is insufficient to prevent restenosis.

miR-18a-5p Promotes Proliferation and Migration of Vascular Smooth Muscle Cells by Activating the AKT/Extracellular Regulated Protein Kinases (ERK) Signaling Pathway.

BACKGROUND microRNAs (miRNAs) play important roles in abnormal proliferation and migration of vascular smooth muscle cells (VSMCs), which lead to restenosis in coronary artery disease. Nevertheless, the role of miR-18a-5p and how it works in VSMCs remain unknown. MATERIAL AND METHODS miR-18a-5p expression was determined by fluorescence quantitative real-time polymerase chain reaction (qRT-PCR) analysis of tissues from 20 patients with stent restenosis, and rats with carotid artery injury, as well as VSMCs. A cell viability assay was used to measure cell proliferation. Cell migration abilities were assessed by transwell migration assay and wound healing assays. To identify miR-18a-5p targets, a dual-luciferase reporter assay was performed. Western blot analysis and immunofluorescence techniques were used to assess the protein expression levels of AKT and ERK. The rescue effects of miR-18a-5p on the proliferation or migration of VSMCs were evaluated after exposure to the AKT inhibitor MK-2206 and ERK inhibitor PD98059. RESULTS The expression level of miR-18a-5p was significantly higher in the blood serum of patients with stent restenosis and in rats with carotid artery injury, and the expression of AKT and ERK was higher after carotid artery injury. The proliferation and migration abilities of VSMCs were accelerated by the overexpression of miR-18a-5p. It was found that miR-18a-5p directly modulates AKT/ERK signaling. Upregulated miR-18a-5p increased the protein expression levels of AKT and ERK and we found a positive correlation between miR-18a-5p expression level and expression of AKT and ERK. Additionally, the promoting effect of miR-18a-5p on VSMCs proliferation, migration, and invasion was reversed by ERK inhibitor or AKT inhibitor. CONCLUSIONS miR-18a-5p can promote proliferation of VSMCs by activating the AKT/ERK signaling pathway.

Potential of circulating pro-angiogenic microRNA expressions as biomarkers for rapid angiographic stenotic progression and restenosis risks in coronary artery disease patients underwent percutaneous coronary intervention.

BACKGROUND: This study aimed to investigate the correlation of pro-angiogenic microRNA (miRNA) expressions with rapid angiographic stenotic progression (RASP) and restenosis risks in coronary artery disease (CAD) patients underwent percutaneous coronary intervention (PCI) with drug-eluting stents (DES). METHODS: A total of 286 CAD patients underwent PCI with DES were consecutively recruited in this study. Plasma samples were collected before PCI operation, and 14 pro-angiogenic miRNAs were measured by real-time quantitative reverse transcription-polymerase chain reaction. Rapid angiographic stenotic progression at nontarget lesions and restenosis at stented lesions were evaluated by quantitative coronary angiography at 12 months after PCI operation. RESULTS: The occurrence rates of RASP and restenosis were 39.5% and 22.4%, respectively. Let-7f, miR-19a, miR-19b-1, miR-92a, miR-126, miR-210, and miR-296 were decreased in RASP patients than non-RASP patients, among which let-7f, miR-19a, miR-126, miR-210, and miR-296 independently correlated with lower RASP occurrence by multivariate analysis, followed by receiver-operating characteristic (ROC) curve exhibited that these five miRNAs showed great value in predicting RASP risk with area under curve (AUC) 0.879 (95% CI: 0.841-0.917). Besides, let-7f, miR-19a, miR-92a, miR-126, miR-130a, and miR-210 were reduced in restenosis patients than non-restenosis patients, among them miR-19a, miR-126, miR-210, and miR-378 independently correlated with lower restenosis occurrence by multivariate analysis, followed by ROC curve disclosed that these four miRNAs had good value in predicting restenosis risk with AUC 0.776 (95% CI: 0.722-0.831). CONCLUSIONS: Circulating let-7f, miR-19a, miR-126, miR-210, and miR-296 independently correlate with reduced RASP risk, while miR-19a, miR-126, miR-210, and miR-378 independently correlate with decreased restenosis risk in CAD patients underwent PCI with DES.

miR-146a and miR-146b predict increased restenosis and rapid angiographic stenotic progression risk in coronary heart disease patients who underwent percutaneous coronary intervention.

OBJECTIVE: This study aimed to investigate the potential of microRNA (miR)-146a and miR-146b for predicting restenosis and rapid angiographic stenotic progression (RASP) risk in coronary heart disease (CHD) patients who underwent percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation. METHODS: In total, 255 CHD patients who underwent PCI with DES were enrolled, and their baseline, procedural, and post procedure characteristics were recorded. Plasma samples were obtained before PCI treatment to detect the miR-146a and miR-146b expression by reverse transcription quantitative polymerase chain reaction. Besides, restenosis and RASP occurrences were assessed based on coronary angiograms at 12 months after the surgery. RESULTS: The occurrence rates of restenosis and RASP were 9.0% and 32.9% respectively in CHD patients who underwent PCI with DES. Furthermore, miR-146a and miR-146b expressions were elevated in CHD patients with restenosis compared with CHD patients without restenosis. Subsequent receiver operating characteristic (ROC) curve analysis showed that miR-146a (area under the curve (AUC), 0.674; 95% CI, 0.567-0.781) and miR-146b (AUC, 0.801; 95% CI, 0.729-0.875) could predict increased restenosis risk, among which miR-146b numerically exhibited a better predictive value for higher restenosis risk. Besides, miR-146a and miR-146b expressions were raised in CHD patients with RASP compared with CHD patients without RASP. Followed ROC curve analysis illuminated that miR-146a (AUC, 0.772; 95% CI, 0.714-0.829) and miR-146b (AUC, 0.706; 95% CI, 0.644-0.769) presented similar values in predicting elevated RASP risk. CONCLUSION: miR-146a and miR-146b predict increased restenosis and RASP risk in CHD patients who underwent PCI with DES.

miR-196a2 (rs11614913) polymorphism is associated with coronary artery disease, but not with in-stent coronary restenosis.

OBJECTIVE: The aim of the study was to evaluate the association of miRNA-146a G/C (rs2910164), and miRNA-196a2 C/T (rs11614913) polymorphisms with the presence of coronary artery disease (CAD) and/or restenosis in patients with coronary stent. MATERIALS AND METHODS: The polymorphisms were determined in 218 patients with CAD who underwent coronary artery stenting (66 with restenosis and 152 without restenosis) and 611 healthy controls using 5' exonuclease TaqMan assays. RESULTS: The distribution of both polymorphisms was similar in patients with and without restenosis. However, when the whole group of patients (with and without restenosis) was compared to healthy controls, under co-dominant, dominant and additive genetic models, the T allele of the miRNA-196a2 C/T (rs11614913) polymorphism was associated with increased risk of CAD (OR = 2.18, Pco-dom = 0.006, OR = 1.86, Pdom = 0.002, and OR = 1.52, Padd = 0.002, respectively). All models were adjusted for age, type 2 diabetes mellitus, dyslipidemia, hypertension and smoking habit. The "GT" haplotype was associated with increased risk of developing CAD (OR = 1.36, P = 0.046). CONCLUSIONS: Our data suggests that the T allele of the miRNA-196a2 C/T (rs11614913) polymorphism is associated with the risk of developing CAD, but no association with restenosis was observed.

Fufang-Zhenzhu-Tiaozhi Capsule reduces restenosis via the downregulation of NF-kappaB and inflammatory factors in rabbits.

BACKGROUND: To investigate the effects of a Chinese herbal medicine Fufang-Zhenzhu Tiaozhi Capsule (FTZ) on restenosis and elucidate the mechanism of action. METHODS: A restenosis model was established by balloon rubbing the endothelium of the abdominal aorta followed by high fat diet. Rabbits were divided into blank control group, restenosis group, FTZ group (0.66 mg/kg/day), atorvastatin group (5 mg/kg/day) and FTZ + atorvastatin group (n = 8). Vascular stenosis was analyzed by X-ray. Serum levels of chemokines and cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-12 (IL-12), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) were measured by ELISA. The levels of NF-κB, IκB-α, P-IκBα, IKK-α, and P-IKKα/ß from injured abdominal arteries were detected by Western blotting. RESULTS: Restenosis was induced successfully via abdominal artery balloon injuries and high fat diet. Restenosis was significantly decreased in FTZ group compared with restenosis group (P < 0.05). FTZ group had markedly reduced serum lipid levels (P < 0.05). In addition, the levels of TNF-α, IL-1, IL-6, IL-8, IL-12, ICAM-1 and MCP-1 decreased by FTZ treatment (P < 0.05). The expression of NF-κB in the atherosclerotic lesions was significantly attenuated in FTZ group (P < 0.05). CONCLUSION: FTZ could reduce restenosis via reducing NF-κB activity and inflammatory factor expression within the atherosclerotic lesion in a rabbit restenosis model. FTZ may be a new therapeutic agent for restenosis.

Inhibition of DNA methyltransferase-1 instigates the expression of DNA methyltransferase-3a in angioplasty-induced restenosis.

Increased expression of DNA methyltransferase-1 (DNMT1) associates with the progression of many human diseases. Because DNMT1 induces cell proliferation, drugs that inhibit DNMT1 have been used to treat proliferative diseases. Because these drugs are nonspecific inhibitors of DNMT1, subsidiary events or the compensatory mechanisms that are activated in the absence of DNMT1 limit their therapeutic application. Here, we studied the molecular mechanisms that occur during angioplasty-induced restenosis and found that DNMT1 inhibition in both in vitro and in vivo approaches resulted in the induction of DNA methyltransferase-3a (DNMT3a) expression. In vascular smooth muscle cells (VSMCs), the microRNA hsa-miR-1264 mimic, specifically inhibiting DNMT1, induced nuclear expression of DNMT3a. On the contrary, there was no induced expression of DNMT3a in VSMCs that were transfected with hsa-miR-1264 inhibitor. Further, ectopic expression of suppressor of cytokine signaling 3 (SOCS3) through adeno-associated virus (AAV)-mediated gene delivery in the coronary arteries of Yucatan microswine showed inhibition of both DNMT1 and DNMT3a in vivo. These findings show the existence of an inter-regulatory mechanism between DNMT1 and DNMT3a where, in the absence of DNMT1, induction of DNMT3a compensates for the loss of DNMT1 functions, suggesting that the inhibition of both DNMT1 and DNMT3a are required to prevent restenosis.

Local adventitial anti-angiogenic gene therapy reduces growth of vasa-vasorum and in-stent restenosis in WHHL rabbits.

BACKGROUND: Antiproliferative drugs in drug eluting stents (DES) are associated with complications due to impaired re-endothelialization. Additionally, adventitial neovascularization has been suggested to contribute to in-stent restenosis (ISR). Since Vascular Endothelial Growth Factors (VEGFs) are the key mediators of angiogenesis, we investigated feasibility and efficacy of local gene therapy for ISR utilizing soluble decoy VEGF receptors to reduce biological activity of adventitial VEGFs. METHOD: Sixty-nine adult WHHL rabbit aortas were subjected to endothelial denudation. Six weeks later catheter-mediated local intramural infusion of 1.5x10e10 pfu adenoviruses encoding soluble VEGF Receptor-1 (sVEGFR1), sVEGFR2, sVEGFR3 or control LacZ and bare metal stent implantation were performed in the same aortic segment. Marker protein expression was assessed at 6d in LacZ cohort. Immunohistochemistry, morphometrical analyses and angiography were performed at d14, d42 and d90. RESULTS: Transgene expression was localized to adventitia. All decoy receptors reduced the size of vasa-vasorum at 14d, AdsVEGFR2 animals also had reduced density of adventitial vasa-vasorum, whereas AdsVEGFR3 increased the density of vasa-vasorum. At d42, AdsVEGFR1 and AdsVEGFR2 reduced ISR (15.7 ±â€¯6.9% stenosis, P < 0.01 and 16.5 ±â€¯2.7%, P < 0.05, respectively) vs. controls (28.3 ±â€¯7.6%). Moreover, AdsVEGFR-3 treatment led to a non-significant trend in the reduction of adventitial lymphatics at all time points and these animals had significantly more advanced neointimal atherosclerosis at 14d and 42d vs. control animals. CONCLUSIONS: Targeting adventitial neovascularization using sVEGFR1 and sVEGFR2 is a novel strategy to reduce ISR. The therapeutic effects dissipate at late follow up following short expression profile of adenoviral vectors. However, inhibition of VEGFR3 signaling accelerates neoatherosclerosis.

The Relationship between VEGFA and TGFB1 Polymorphisms and Target Lesion Revascularization after Elective Percutaneous Coronary Intervention.

BACKGROUND AND AIM: The specific association between genetic variation and in-stent restenosis is still only partly understood. The aim of this study is to analyze the relationship between functional polymorphisms in the genes encoding vascular endothelial growth factor A (VEGF-A; rs699947) and transforming growth factor beta 1 (TGF-ß1; rs1800470) and target lesion revascularization (TLR) risk. METHODS: A total of 676 patients (805 lesions) with stable coronary artery disease (SCAD) who received elective percutaneous coronary intervention (PCI) with at least one bare-metal stent implantation were included. The primary study endpoint was TLR at a 4-year follow-up. RESULTS: The TLR rate was higher in patients with the VEGFA A/A genotype (15.4%) than in patients with the VEGFA A/C (7.9%) and C/C (8.9%) genotypes (p = 0.009). The VEGFA A/A genotype, after adjustment for clinical and procedural covariates, remained significantly and independently associated with the TLR (hazard ratio-2.09 [95% confidence interval 1.32-3.33, p = 0.0017]). However, we found no association between TLR and the TGFB1 genotype. CONCLUSION: The VEGFA A/A genotype is significantly and independently associated with TLR risk in Polish SCAD patients who received elective PCI with bare-metal stent implantation.

Association between VEGF Gene Polymorphisms and In-Stent Restenosis after Coronary Intervention Treated with Bare Metal Stent.

Background. In-stent restenosis (ISR) is the gradual narrowing of the vessel lumen after coronary stent implantation due to the increase in vascular smooth muscle cell proliferation. Vascular endothelial growth factor (VEGF) protein plays an important role in this process. Our aim was to analyze the association of single nucleotide polymorphisms of the VEGF gene (rs2010963 and rs6999447) with the occurrence of ISR after coronary artery bare metal stent (BMS) implantation. Methods. 205 patients with a history of BMS implantation and a repeated coronarography were prospectively enrolled. Patients were assigned to diffuse restenosis group (n = 105) and control group (n = 100) and VEGF genotypes were determined. Results. Diffuse ISR was significantly more frequently observed in patients with homozygous normal genotype of rs2010963 polymorphism, and this polymorphism was independently associated with diffuse ISR. Conclusions. RS2010963 is associated with higher incidence of development of diffuse coronary ISR in patients treated with BMS implantation.

Stent-mediated gene and drug delivery for cardiovascular disease and cancer: A brief insight.

This review concisely recapitulates the different existing modes of stent-mediated gene/drug delivery, their considerable advancement in clinical trials and a rationale for other merging new technologies such as nanotechnology and microRNA-based therapeutics, in addition to addressing the limitations in each of these perpetual stent platforms. Over the past decade, stent-mediated gene/drug delivery has materialized as a hopeful alternative for cardiovascular disease and cancer in contrast to routine conventional treatment modalities. Regardless of the phenomenal recent developments achieved by coronary interventions and cancer therapies that employ gene and drug-eluting stents, practical hurdles still remain a challenge. The present review highlights the limitations that each of the existing stent-based gene/drug delivery system encompasses and therefore provides a vision for the future with respect to discovering an ideal stent therapeutic platform that would circumvent all the practical hurdles witnessed with the existing technology. Further study of the improvisation of next-generation drug-eluting stents has helped to overcome the issue of restenosis to some extent. However, current stent formulations fall short of the anticipated clinically meaningful outcomes and there is an explicit need for more randomized trials aiming to further evaluate stent platforms in favour of enhanced safety and clinical value. Gene-eluting stents may hold promise in contributing new ideas for stent-based prevention of in-stent restenosis through genetic interventions by capitalizing on a wide variety of molecular targets. Therefore, the central consideration directs us toward finding an ideal stent therapeutic platform that would tackle all of the gaps in the existing technology.

Diagnostic value of microRNA-143 in predicting in-stent restenosis for patients with lower extremity arterial occlusive disease.

PURPOSE: This study was conducted to explore the diagnostic value of microRNA-143 (miRNA-143) in predicting in-stent restenosis (ISR) of lower extremity arterial occlusive disease (LEAOD). METHODS: From February 2012 to March 2015, 165 patients (112 males and 53 females) with LEAOD undergoing interventional treatment were enrolled in this study. Serum miRNA-143 expression was detected using quantitative real-time polymerase chain reaction (qRT-PCR). Patients were assigned into the restenosis and non-restenosis groups according to routine surveillance postoperative angiography. A logistic regression analysis was conducted to analyze the risk factors for ISR in LEAOD patients. A receiver operating characteristic (ROC) curve was drawn to evaluate the diagnostic value of miRNA-143 in predicting ISR for LEAOD patients. RESULTS: There were 74 and 91 patients in the restenosis and non-restenosis groups, respectively. Before the treatment, there were significant differences in history of diabetes, smoking status, blood sugar level (BSL) at admission, low-density lipoprotein cholesterol (LDL-C) level, and stent diameter between the restenosis and non-restenosis groups (all P < 0.05). Serum miRNA-143 expression was lower in the restenosis group than in the non-restenosis group (P < 0.05). Serum miRNA-143 expression in the restenosis group was correlated with smoking status, history of diabetes, BSL, and LDL-C (all P < 0.05). Logistic regression analysis demonstrated that miRNA-143, LDL-C, and smoking status were correlated with the postoperative ISR (all P < 0.05). ROC curve analysis revealed that the area under the curve (AUC) of miRNA-143 in predicting ISR for LEAOD patients was 0.866. CONCLUSION: Our results indicate that miRNA-143 can be a promising tool for predicting the ISR in LEAOD patients.

Therapeutic Effect of Akt1 siRNA Nanoparticle Eluting Coronary Stent on Suppression of Post-Angioplasty Restenosis.

For effective treatment of restenosis, therapeutic genes are delivered locally from a coated stent at the site of injury, leading to inhibition of smooth muscle proliferation and neo-intimal hyperplasia while promoting re-endothelialization. In a previous study, we delivered Akt1 siRNA nanoparticles (ASNs) from a hyaluronic acid (HA)-coated stent surface to specifically suppress the pro-proliferative Akt1 protein in smooth muscle cells (SMCs). In the present study, therapeutic efficacy was investigated in a rabbit restenosis model after percutaneous implantation of an ASN-immobilized stent in a rabbit iliac artery. Quantitative and qualitative analyses of in-stent restenosis were investigated in an in vivo animal model by micro-CT imaging and SEM observation, respectively. Proliferation status and neo-intima formation of the vascular tissues located near ASN-immobilized stents were analyzed by immunohistochemical staining using anti-Akt1 and anti-Ki67 antibodies and histological analyses, such as hematoxylin and eosin staining and Verhoeff's elastic stain. Re-endothelialization after implantation of an ASN-immobilized stent was also analyzed via immunohistochemistry using an anti-CD31 antibody. To elucidate the molecular mechanism related to reducing SMC proliferation and subsequent inhibition of in-stent restenosis in vivo, protein and mRNA expression of Akt1 and downstream signaling proteins were analyzed after isolating SMC-rich samples from the treated vasculature. The implanted Akt1 siRNA-eluting stent efficiently mitigated in-stent restenosis without any side effects and can be considered a successful substitute to current drug-eluting stents.

The Relationships between Polymorphisms in Genes Encoding the Growth Factors TGF-ß1, PDGFB, EGF, bFGF and VEGF-A and the Restenosis Process in Patients with Stable Coronary Artery Disease Treated with Bare Metal Stent.

BACKGROUND: Neointima forming after stent implantation consists of vascular smooth muscle cells (VSMCs) in 90%. Growth factors TGF-ß1, PDGFB, EGF, bFGF and VEGF-A play an important role in VSMC proliferation and migration to the tunica intima after arterial wall injury. The aim of this paper was an analysis of functional polymorphisms in genes encoding TGF-ß1, PDGFB, EGF, bFGF and VEGF-A in relation to in-stent restenosis (ISR). MATERIALS AND METHODS: 265 patients with a stable coronary artery disease (SCAD) hospitalized in our center in the years 2007-2011 were included in the study. All patients underwent stent implantation at admission to the hospital and had another coronary angiography performed due to recurrence of the ailments or a positive result of the test assessing the coronary flow reserve. Angiographically significant ISR was defined as stenosis >50% in the stented coronary artery segment. The patients were divided into two groups-with angiographically significant ISR (n = 53) and without significant ISR (n = 212). Additionally, the assessment of late lumen loss (LLL) in vessel was performed. EGF rs4444903 polymorphism was genotyped using the PCR-RFLP method whilst rs1800470 (TGFB1), rs2285094 (PDGFB) rs308395 (bFGF) and rs699947 (VEGF-A) were determined using the TaqMan method. RESULTS: Angiographically significant ISR was significantly less frequently observed in the group of patients with the A/A genotype of rs1800470 polymorphism (TGFB1) versus patients with A/G and G/G genotypes. In the multivariable analysis, LLL was significantly lower in patients with the A/A genotype of rs1800470 (TGFB1) versus those with the A/G and G/G genotypes and higher in patients with the A/A genotype of the VEGF-A polymorphism versus the A/C and C/C genotypes. The C/C genotype of rs2285094 (PDGFB) was associated with greater LLL compared to C/T heterozygotes and T/T homozygotes. CONCLUSIONS: The polymorphisms rs1800470, rs2285094 and rs6999447 of the TGFB1, PDGFB and VEGF-A genes, respectively, are associated with LLL in patients with SCAD treated by PCI with a metal stent implantation.

Asociación de polimorfismos del gen factor de necrosis tumoral (TNF) con el desarrollo de reestenosis de stent post angioplastía coronaria / Polymorphisms of tumor necrosis factor gen: are they associated to stent restenosis after coronary angioplasty?

Introducción: La intervención coronaria percutánea (PCI en inglés) con implante de stent coronario es uno de los procedimientos más utilizados para la revascularización miocárdica en condiciones agudas o crónicas. Múltiples factores se han relacionado con la restenosis de stent, incluyendo aspectos clínicos, angiográficos, genéticos y epigenéticos. La respuesta inflamatoria en gran parte está determinada genéticamente y probablemente sea el rol más importante en la restenosis. El factor de necrosis tumoral a (TNF-α;) es un mediador clave en la respuesta inflamatoria actuando en sitios de injuria tisular inducida por el daño de las paredes del vaso. Objetivo: Determinar la asociación entre polimorfismos genéticos del TNF y restenosis en pacientes coronarios sometidos a angioplastía. Métodos: Se diseñó un estudio de casos y controles incidentes no pareados, aprobado por el comité de ética institucional. Se incluyeron pacientes con cardiopatía coronaria sometidos a PCI con implante de stent BMS o DES, con un tiempo de control angiográfico mayor de 6 meses. Los casos fueron definidos como aquellos pacientes con estenosis de stent >50% y como controles aquellos con estenosis <50%, con respecto del lumen del vaso de referencia. Se efectuó la genotipificación de los polimorfismos rs361525 (-238G/A) y rs1799964 (-1031 T/C) del gen TNF mediante PCR en tiempo real mediante sondas alelo-específicas. Además, se registraron variables clínicas y demográficas. Resultados: Se incluyó en este estudio de análisis de genotipificación del polimorfismo del gen TNF 82 pacientes como casos, y 102 controles. No hubo diferencias significativas en las siguientes variables clínicas y demográficas: edad (63.7 ± 10.5 vs. 65.4 ± 9.6 años; p=0.24), género masculino (75 vs. 69%, p=0.5), IMC (28.5 ± 3.6 vs. 28 ± 3.8 Kg/m2; p=0.78) y tabaquismo (79 vs. 77%; p=0.7). En contraste, se observó una diferencia significativa en la frecuencia de DM-2 casos y controles (43.2 vs. 26.5%; p=0.03) y %HbA1c entre ambos grupos (6.78 ± 1.5 vs. 6.1 ± 0.8%; p=0.01). Respecto a las variantes genéticas estudiadas, no hubo diferencias significativas en la frecuencia relativa del alelo mutado tanto para el polimorfismo rs361525 (Alelo A, casos: 0.06 vs. controles: 0.08; p=0.37), como para la variante rs1799964 (Alelo C, casos: 0.2 vs. controles: 0.2; p=0.96). Las OR asociadas a dichos alelos fueron 0.68 (I.C. 95%= 0.29 - 1.59) y 0.99 (I.C. 95%= 0.58 - 1.67), respectivamente; confirmando la ausencia de asociación. Conclusión: Nuestros datos sugieren que las variantes genéticas estudiadas no están relacionadas al desarrollo de restenosis en los sujetos estudiados, y probablemente en nuestra población los factores clínicos sean más determinantes para el desarrollo de reestenosis coronaria post angioplastía que los factores genéticos.

Multiple factors have been associated to the development of stent restenosis after coronary angioplasty (PCA). including clinical, angiographic, genetic and epigenetic factors. The inflammatory response is genetically determined and it may be the most important factor. Tumor necrosis factor a (TNFα) is a potent mediator of this response at the endothelial wall. Aim: To determine the association between TNFα; genetic polymorphisms and stent restenosis. Methods: A case-control study was performed in patients submitted to PTCA with stent implantation(-bare metal or drug eluting stent) at least 6 months prior to the study. Cases were defined by the presence of >50% intra stent stenosis. PCR was used for type classification of polymorphisms rs361525 (-238G/A) y rs1799964 (-1031 T/C) of the TNFα; gene. Results: 82 cases and 102 controls were included. No differences were observed in clinical and demographic variables: age (63.7 ± 10.5 vs. 65.4 ± 9.6 years, p=0.24, for cases and controls, respectively), male gender (75 vs. 69%, p=0.5), BMI (28.5 ± 3.6 vs. 28 ± 3.8 Kg/m2, p=0.78) and active smoking (79 vs. 77%, p=0.7). In contrast, Diabetes was more frequent in cases than in controls (43.2 vs. 26.5%, p=0.03). There was no difference in the relative frequency of mutations of the rs361525 polymorphism (Allele A, 0.06 vs 0.08, p=0.37 for cases and controls, respectively) nor for variant rs1799964 (0.2 in both cases and controls). Non significant associations were confirmed by Odd ratios with 0 included in the 95% confidence interval. Conclusion: No association of genetic polymorphisms of TNFa and stent restenosis was found, which suggests that clinical factors my be more important for the development of post PTCA stent restenosis.

miR-599 Inhibits Vascular Smooth Muscle Cells Proliferation and Migration by Targeting TGFB2.

Aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) play a crucial role in the pathogenesis of cardiovascular diseases including coronary heart disease, restenosis and atherosclerosis. MicroRNAs are a class of small, non-coding and endogenous RNAs that play critical roles in VSMCs function. In this study, we showed that PDGF-bb, as a stimulant, promoted VSMCs proliferation and suppressed the expression of miR-599. Moreover, overexpression of miR-599 inhibited VSMCs proliferation and also suppressed the PCNA and ki-67 expression. In addition, we demonstrated that ectopic expression of miR-599 repressed the VSMCs migration. We also showed that miR-599 inhibited type I collagen, type V collagen and proteoglycan expression. Furthermore, we identified TGFb2 as a direct target gene of miR-599 in VSMCs. Overexpression of TGFb2 reversed miR-599-induced inhibition of VSMCs proliferation and type I collagen, type V collagen and proteoglycan expression. In conclusion, our findings suggest miR-599 plays a crucial role in controlling VSMCs proliferation and matrix gene expression by regulating TGFb2 expression.

The C4280A (rs5705) gene polymorphism of the renin (REN) gene is associated with risk of developing coronary artery disease, but not with restenosis after coronary stenting.

The aim of the present study was to evaluate the role of AGT and REN gene polymorphisms as susceptibility markers for coronary artery disease (CAD) and/or restenosis after coronary stent placement in a group of Mexican patients. Five polymorphisms of the AGT (rs699, rs4762, rs5051, rs5049, rs5046) and two of the REN (rs5707, rs5705) genes were analyzed by 5' exonuclease TaqMan genotyping assays in 240 patients with CAD who underwent coronary artery stenting (76 with restenosis and 164 without restenosis). A group of 610 individuals without clinical and familial antecedents of cardiovascular diseases were included as controls. The results showed that the distribution of AGT and REN polymorphisms were similar in patients with and without restenosis. However, when the whole group of patients (with and without restenosis) was compared to healthy controls, under co-dominant, dominant, heterozygous and additive models, the REN A4280C (rs5705) polymorphism was associated with increased risk of CAD (OR=1.76, PCo-dom=0.006, OR=1.81, PDom=0.001, OR=1.75, PHet=0.003 and OR=1.59, PAdd=0.003, respectively). All models were adjusted for age, gender, diabetes, dyslipidemia, hypertension and smoking habit. The TC haplotype of the REN gene was associated with increased risk of CAD (OR=1.53, P=0.014). The data suggest that the REN C4280A (rs5705) polymorphism plays an important role in the risk of developing CAD with the highest risk for C allele, but do not support its role as a risk factor for developing restenosis after coronary stenting.