Neointimal Thickness Research Articles

The effects of glycaemic variability on intimal hyperplasia and plaque stability after stenting via autophagy-mediated G3BP1/NLRP3 inflammasome.

BackgroundThe objective of this study was to investigate the effects of glycaemic variability (GV) on intimal hyperplasia and plaque stability after coronary stenting via autophagy-mediated G3BP1/NLRP3 inflammasome signalling.MethodsIn the clinical study, between July 2017 and December 2017, 95 patients with acute myocardial infarction (AMI) and diabetes mellitus (DM) comorbidity received stent implantation. The patients were followed up for 2 years after discharge. The patients were divided into a low-GV (n=61) and high-GV (n=34) group, and the incidence of recurrent AMI was measured. In the animal study, thirteen pigs were divided into a sham (n=3), low-GV DM (n=5) and high-GV DM group (n=5). Intima samples were analysed by optical coherence tomography 22 weeks after coronary stenting. Becn1, LC3B, p62, G3BP1 and NLRP3 protein levels in the intima were examined by western blot. In vitro experiments with THP-1 cells were also conducted.ResultsIn the high-GV group, patients exhibited a higher recurrent AMI, greater neointimal thickness, increased p62 and NLRP3 expression, and decreased Becn1, LC3B and G3BP1 expression compared with the low-GV group (P<0.05). The effects of high GV could be abolished by rapamycin but were aggravated by 3-methyladenine.ConclusionsGV might impact the intimal hyperplasia and plaque stability via autophagy-mediated G3BP1/NLRP3 inflammasome signalling. GV and the autophagy-mediated G3BP1/NLRP3 inflammasome may be promising targets for the treatment of coronary heart disease.

The association of diabetes mellitus with neointimal formation following deployment of second-generation drug-eluting stents: an optical coherence tomographic study.

The purpose of this study was to evaluate the association of diabetes mellitus (DM) with neointimal formation after implantation of second-generation drug-eluting stent (DES) visualized by optical coherence tomography (OCT). Patients with single de novo coronary artery disease treated with second-generation DES between June 2014 and June 2017 in our department underwent OCT examination at 1-year follow-up and were enrolled in this retrospective study. The primary end point was in-stent mean neointimal thickness (MNT), and secondary end points included uncovered stent strut, minimal lumen area (MLA), neointimal burden, neointimal hyperplasia (NIH) patterns and stent thrombosis (ST) after 1 year of OCT follow-up. A total of 68 patents with DM (DM group) and 216 patients without DM (non-DM group) were enrolled. At 1-year follow-up, the DM group compared with the non-DM group, showed: MNT [160 (85-245) μm vs. 120 (60-220) μm, P = 0.038] and neointimal burden [21.4 (8.3-30.1)% vs. 14.0 (5.7-26.1)%, P = 0.023] to be significantly increased. Concurrently, MLA [4.60 (3.53-6.06) mm vs. 5.76 (4.28-7.20) mm2, P = 0. 0.002] was significantly reduced. Interestingly, the degree of uncovered struts (7.3 ± 7.1% vs. 7.7 ± 6.7%, P = 0.704), NIH patterns (P = 0.984), and ST (7.9% vs. 7.4%, P = 0.88) were comparable between the two groups. After propensity score matching, the MNT [160 (90-240) μm vs. 110 (60-220) μm, P = 0.048] and neointimal burden [21.4 (8.3-30.1)% vs. 15.4 (5.6-26.3)%, P = 0.044] remained significantly different in the DM compared to the non-DM group. DM leads to significant increase in MNT and neointimal burden even with second-generation DES, nevertheless stent strut coverage, ST and NIH characteristics remained comparable among the cohorts at 1-year.

INFLUENCE OF Β-CATENIN ON THE PROLIFERATION OF VASCULAR SMOOTH MUSCLE CELLS AND THE DEVELOPMENT OF CARDIAC ALLOGRAFT VASCULOPATHY IN MICE

Objectives: β-Catenin is the central signaling molecule in the canonical wnt pathway. Blocking its actions is associated with anti-proliferative effects on different cell lines including vascular smooth muscle cells (VSMCs), which play amajor role in the development of cardiac allograft vasculopathy (CAV) after heart transplantation. Aim of this study was to analyse the inhibition of β-Catenin as potential target to prevent CAV. Methods: VSMCs from mouse (muSMCs) and human (huSMCs) arteries were cultivated with increasing concentrations of the β-Catenin signaling inhibitors XAV-939, ICG-001 or PKF118-310. The reduced proliferation ability of muSMCs and huSMCs was detected using PrestoBlue Cell Viability Reagent. To verify β-Catenin inhibition as the mechanism of action, expression of its target genes Axin2, Cyclin D1 and p21 was analyzed. Additionally, the inhibitors were used in vivo to treat mice after aortic transplantation to evaluate the effect on reducing CAV by measuring neointimal thickness (n=8 / group). Additionally, the amount of neointimal β-Catenin was examined by immunofluorescence staining and expression of several inflammatory cytokines was analyzed by Taqman PCR. Results: All β-Catenin signaling inhibitors showed a dose-dependent proliferation inhibition of cultivated muSMCs and huSMCs. PKF118-310 led to cell death in the highest concentrations used. In vivo though, no relevant reduction in CAV was detectable after treatment with XAV-939 or ICG-001. Respective experiments with PKF118-310 are conducted at the moment. Interestingly, neointimal percentages of β-Catenin were reduced after XAV-939 and ICG-001. ICG-001 treatment also led to reduced expression of INFγ, TNFα and IL-6 while this could not be found after XAV-939 application. β-Catenin target gene expression is currently analyzed. Conclusion: In vitro, strong anti-proliferative effects of the β-Catenin inhibitors were detected on cultured VSMC, whereas no relevant inhibition of CAV development in a mouse model could be seen. We would speculate at this stage, that this is attributable to the complexity of the wnt/ β-Catenin pathway on the one hand as well as that of CAV development on the other hand. Deutsche Stiftung für Herzforschung.

Inhibition of programmed death-1 decreases neointimal hyperplasia after patch angioplasty.

Neointimal hyperplasia remains an obstacle after vascular interventions. Programmed death-1 (PD-1) antibody treatment decreases tumor cell proliferation and secretion of inflammatory factors, and several antineoplastic drugs show efficacy against neointimal hyperplasia. We hypothesized that inhibition of PD-1 inhibits neointimal hyperplasia in a rat patch angioplasty model. In a rat aorta patch angioplasty model, four groups were compared: the control group without treatment, a single dose of humanized PD-1 antibody (4 mg/kg) injected immediately after patch angioplasty, PD-1 antibody-coated patches, and BMS-1 (PD-1 inhibitor)-coated patches. Patches were harvested (Day 14) and analyzed. After patch angioplasty, PD-1-positive cells were present. Inhibition of PD-1 using both intraperitoneal injection of humanized PD1 antibody as well as using patches coated with humanized PD1 antibody significantly decreased neointimal thickness (p = 0.0199). There were significantly fewer PD-1 (p = 0.0148), CD3 (p = 0.0072), CD68 (p = 0.0001), CD45 (p = 0.001), and PCNA (p < 0.0001)-positive cells, and PCNA/α-actin dual positive cells (p = 0.0005), in the treated groups. Patches coated with BMS-1 showed similarly decreased neointimal thickness and accumulation of inflammatory cells. Inhibition of PD-1 using PD-1 antibody or its inhibitor BMS-1 can significantly decrease neointimal thickness in vascular patches. Inhibition of the PD-1 pathway may be a promising therapeutic strategy to inhibit neointimal hyperplasia.

Successful Reduction of Neointimal Hyperplasia on Stainless Steel Coronary Stents by Titania Nanotexturing.

Bare metal stents (BMSs) of stainless steel (SS) were surface engineered to develop nanoscale titania topography using a combination of physical vapor deposition and thermochemical processing. The nanoleafy architecture formed on the stent surface remained stable and adherent upon repeated crimping and expansion, as well as under flow. This titania nanoengineered stent showed a preferential proliferation of endothelial cells over smooth muscle cells in vitro, which is an essential requirement for improving the in vivo endothelialization, with concurrent reduction of intimal hyperplasia. The efficacy of this surface-modified stent was assessed after implantation in rabbit iliac arteries for 8 weeks. Significant reduction in neointimal thickening and thereby in-stent restenosis with complete endothelial coverage was observed for the nanotextured stents, compared to BMSs, even without the use of any antiproliferative agents or polymers as in drug-eluting stents. Nanotexturing of stents did not induce any inflammatory response, akin to BMSs. This study thus indicates the effectiveness of a facile titania nanotopography on SS stents for coronary applications and the possibility of bringing this low-priced material back to clinics.

Vein Source Influences Neointimal Response in Rat Vein-to-Artery Grafts

BackgroundVein graft stenosis is a major complication of coronary artery bypass surgery and peripheral arterial bypass procedures. Experimental models of this clinical complication have used in vivo grafting procedures, relying on the relatively modest neointimal thickening in these models as a surrogate for clinical graft stenosis without regard to the donor site origin of the vein graft. Materials and methodsIn a standard rat model of vein grafting, three different donor sites were used to supply veins used as interpositional grafts to the femoral artery: the superficial inferior epigastric vein, the common femoral vein, and the posterior facial vein (distal branch of the jugular vein). Grafts were harvested as 4 wk and histomorphometrically evaluated for the extent of neointimal formation and lumen narrowing. ResultsThe posterior facial vein showed significantly thicker neointima and a greater extent of lumen narrowing than the other two graft sources, despite having a similar diameter to the femoral vein and nearly twice the initial diameter of the epigastric vein. ConclusionsThe source of donor graft material can greatly influence the extent of neointimal response after interpositional vein grafting to arterial flow. These findings support use of the posterior facial vein graft over other more standard donor vein grafts in research directed at understanding the causes and prevention of vein graft stenosis.

Combinatorial therapy of sirolimus and heparin by nanocarrier inhibits restenosis after balloon angioplasty ex vivo.

Aim: To develop poly(lactide-co-glycolide)-graft-polyethylenimine (PgP) as a dual drug-delivery carrier for sirolimus (SR) and heparin (Hep) to inhibit restenosis after balloon angioplasty. Materials & methods: SR was loaded in the hydrophobic core and negatively charged Hep complexed with the positively charged hydrophilic shell of PgP. SR- and Hep-loaded PgP was tested on rat aortic smooth muscle cells in vitro and injured porcine coronary arteries after balloon angioplasty ex vivo. Results & conclusion: SR and Hep loading efficiency in PgP were approximately 37 and 82%, respectively. SR- and Hep-loaded PgP treatment decreased smooth muscle cell proliferation up to 14days post-treatment and decreased proliferation, collagen deposition and neointimal thickness and increased patency in porcine coronary arteries after balloon angioplasty ex vivo.

Endothelin-1, endothelin receptor antagonists, and vein graft occlusion in coronary artery bypass surgery: 20 years on and still no journey from bench to bedside.

The saphenous vein is the most commonly used bypass graft in patients with coronary artery disease. During routine coronary artery bypass, grafting the vascular damage inflicted on the vein is likely to stimulate the release of endothelin-1, a potent endothelium-derived vasoconstrictor that also possesses cell proliferation and inflammatory properties, conditions associated with vein graft failure. In both in vitro and in vivo studies, endothelin receptor antagonists reduce neointimal thickening. The mechanisms underlying these observations are multifactorial and include an effect on cell proliferation and cell/tissue damage. Much of the data supporting the beneficial action of endothelin-1 receptor antagonism at reducing intimal thickening and occlusion in experimental vein grafts were published over 20 years ago. The theme of the recent ET-16 conference in Kobe was "Visiting Old and Learning New". This short review article provides an overview of studies showing the potential of endothelin receptor antagonists to offer an adjuvant therapeutic approach for reducing saphenous vein graft failure and poses the question why this important area of research has not been translated from bench to bedside given the potential benefit for coronary artery bypass patients.

Oscillatory shear stress induces the transition of EPCs into mesenchymal cells through ROS/PKCζ/p53 pathway

AimsStudies indicate that the pattern of shear stress determines the direction of endothelial progenitor cells (EPCs) differentiation. However, the mechanism remains largely unknown. Herein, we try to identify the role of oscillatory shear stress (OSS) in the transdifferentiation of EPCs into mesenchymal cells and the mechanism involved. Materials and methodsOSS was applied to EPCs using the flow chamber system in vitro. Matrigel, Boyden chamber, and healing assay were used to observe the changes in EPCs function. Further, 2′,7′-dichlorofluorescein diacetate (DCFH-DA) probe and/or western blot were performed to detect the expression of reactive oxygen species (ROS), p53 and PKCζ in EPCs. EPCs transduced with Lentivirus carrying Tp53 were implanted into the arterial vessel in the balloon injured rat model, and neointimal thickening was verified by HE staining. Key findingsOSS enhanced the expression of mesenchymal cell markers alpha-smooth muscle actin (α-SMA) and smooth muscle 22 alpha (SM22α) on EPCs. In the meantime, OSS time-dependently decreased p53 expression in EPCs, which was partially abolished by treatment with ROS scavenger N-acetylcysteine (NAC) or protein kinase C zeta (PKCζ) inhibitor Go6983. Moreover, the p53 agonist tenovin-1 attenuated the changes of OSS-mediated the mesenchymal cell markers and EPCs function. Besides, we also found that transplanting EPCs transfected with LV-Tp53 significantly inhibited neointimal thickening and promoted reendothelialization in vivo. SignificanceThis study demonstrates OSS-induced EPC transdifferentiation into mesenchymal cells and ROS/PKCζ/p53 pathway play an essential role in it. It may serve as a promising therapeutic target for cardiovascular disease in the future.

Healthy Strut Coverage After Coronary Stent Implantation: An Ex Vivo Human Autopsy Study.

Struts have been considered as covered when tissue overlying the struts is >0 μm by optical coherence tomography (OCT). However, there is no confirmatory study to validate this definition by histology which is the gold standard. The aim of the present study was to assess the appropriate cutoff value of neointimal thickness of stent strut coverage by OCT with histology confirmation. We performed ex vivo OCT imaging of human coronary arteries with stents at autopsy. A total of 46 stents in 39 vessels from 25 patients were examined in this study, and a total of 165 cross-sectional images were co-registered with histology to determine the optimal cutoff value for strut coverage by OCT which was defined as luminal endothelial cells with 2 abluminal layers of smooth muscles cells and matrix. Considering the resolution of OCT is 10 to 20 μm, the cutoff values were assessed at ≥20, ≥40, and ≥60 μm. A total of 2235 struts were reviewed by histology, 1216 were considered as well-matched struts which were analyzed in this study. By histology, 160 struts were identified as uncovered, while 1056 struts were covered. The OCT assessment without consideration of neointimal thickness yielded a poor specificity of 37.5% and sensitivity 100%. Of 3 cutoff values, the cutoff value of ≥40 μm yielded the best sensitivity (99.3%), specificity (91.0%), positive predictive value (98.6%), and negative predictive value (95.6%) as compared with ≥20 and ≥60 μm. Neointimal thickness ≥40 μm by OCT yielded the most accurate cutoff value to identify stent strut coverage validated by histology.

Everolimus-Eluting Biodegradable Abluminal Coating Stent versus Durable Conformal Coating Stent: Termination of the Inflammatory Response Associated with Neointimal Healing in a Porcine Coronary Model.

Objectives We evaluated the effect of the different carrier systems on early vascular response through histological analysis and scanning electron microscopy using a porcine model. Background Although Synergy™ and Promus PREMIER™ share an identical stent material and drug elution (everolimus), they use different drug carrier systems: biodegradable abluminal coating polymer or durable conformal coating polymer, respectively. However, data regarding the impact of the different coating systems on vessel healing are currently limited. Methods Twelve Synergy™ and Promus PREMIER™ were implanted in 12 swine. Histopathological analysis of the stented segments was performed on the 2nd and 14th days after implantation. Morphometric analysis of the inflammation and intimal fibrin content was also performed. Results On the 2nd day, neointimal thickness, percentage of neointimal area, and inflammatory and intimal fibrin content scores were not significantly different between the two groups. On the 14th day, the inflammatory and intimal fibrin content scores were significantly lower in Synergy™ versus those observed in Promus PREMIER™. In Synergy™, smooth muscle cells were found and the neointimal layers were smooth. In contrast, inflammatory cells were observed surrounding the struts of Promus PREMIER™. Conclusions These results demonstrate that termination of reactive inflammation is accelerated after abluminal coating stent versus implantation of conformal coating stent.

Comparison of neointimal coverage between ultrathin biodegradable polymer-coated sirolimus-eluting stents and durable polymer-coated everolimus-eluting stents: 6 months optical coherence tomography follow-up from the TAXCO study.

AimThe TAXCO study was designed to compare the degree of neointimal coverage and the prevalence of malapposition at 6 months subsequent to implantation of ultrathin biodegradable polymer‐coated sirolimus‐eluting stents (SES) and durable polymer‐coated everolimus‐eluting stents (EES) of thin strut thickness using optical coherence tomography (OCT).MethodsThe TAXCO study included a total of 42 patients who gave consent and underwent OCT examination between August 2017 and September 2017. Of 42, five patients' OCT examinations were of insufficient quality for quantitative analysis. Thus, the OCT analysis group consisted of 37 patients. Among them, 16 patients were treated with Xience (Abbott Vascular) and 21 with Tetriflex (Sahajanand Medical Technologies Pvt. Ltd., Surat, India), 6 (±1) months earlier at our institution. The OCT was performed using a C7 Dragonfly™ imaging catheter (St. Jude Medical Inc.). All OCT images were analyzed at an independent core laboratory (Cardiovascular Research Center, São Paulo, Brazil) by analysts who were blinded to patient and procedural information.ResultsA total of 763 crosssections (6,882 struts) were analyzed in Xience group, and 1,127 crosssections (9,968 struts) in Tetriflex group. At 6 months, on per‐lesion basis, no significant differences were observed between Xience group and Tetriflex group in mean percentage of uncovered struts (1.87 ± 3.86 vs. 2.42 ± 3.46, p = .137) and malapposed struts (0.05 ± 0.2 vs. 0.21 ± 0.69, p = .302). Strut‐level neointimal thickness also did not differ between Xience group and Tetriflex group (0.18 ± 0.12 vs. 0.14 ± 0.08 mm, p = .286).ConclusionThis OCT study found no significant difference in strut coverage and neointimal thickness at 6 months after implantation of biodegradable polymer‐coated Tetriflex, when compared with durable polymer‐coated Xience.

Non‐Perfused Coronary Arteries Are Able to Maintain Structural Integrity in Developing Scar Tissue Following a Transmural Myocardial Infarction

IntroductionWhereas considerable effort has been devoted to identify a suitable source of contractile cells to be used for replacement of a post‐myocardial infarction (MI) scar with the newly‐formed cardiac muscle tissue, an exploration for the viable routes of arterial blood supply to the sites of regenerating myocardium remained mostly neglected. However, the presence of a sustainable blood delivery system seems imperative for survival of newly‐grown myocardium.HypothesisWe hypothesize that if the vessels of the original arterial bed, remaining in post‐MI region, will be able to maintain their structural integrity for the duration of post‐MI scar formation they can potentially be suitable for use as a natural blood delivery system to support the regenerating myocardium.MethodsA large transmural MI was induced in middle‐aged, male Sprague‐Dawley rats by permanent ligation of the left coronary artery. Post‐MI rats were euthanized 3, 7 and 14 days after occlusion and their hearts were processed to paraffin for morphological evaluation. Sham‐operated rats were used as age‐matched controls. Serial sections from each heart were stained with various histological techniques or with an anti‐smooth muscle alpha‐actin antibody. Images were captured using a Leica DM 4000B microscope and analyzed by Image‐Pro Analyzer v.7.0 software. Statistical analysis was performed using Prism 6 software package.ResultsWe found that whereas most arterioles and small arteries within an infarcted region have undergone necrosis during 3 days after MI, the medium‐sized and larger arteries appeared to preserve their structural integrity up to 14 days post‐MI. Quantitative assessment showed that surviving residual arteries continued to maintain their structural parameters, such as external diameter, lumen diameter, wall thickness and wall‐to‐lumen ratio, during 7 post‐MI days. However, in 14‐day‐old scars, some non‐perfused arteries began to demonstrate the evidence of noticeable neointimal thickening, composed of activated smooth muscle cells, that narrowed the vessel lumen and led to a significant increase in wall‐to‐lumen ratio (0.35±0.02 in post‐MI rats vs. 0.11±0.01 in sham‐operated rats, P&lt;0.0001). Moreover, the majority of remaining vessels showed a various degree of degenerative changes, including perivascular and intravascular collagen accumulation, disintegration of internal elastic lamina and patchy disappearance of smooth muscle cells from the vessel media.ConclusionOur findings reveal that a number of large and medium‐sized coronary arteries, residing in post‐infarcted region, were capable of maintaining their structural integrity during two post‐MI weeks. This observation supports a concept that these vessels can be used as a potential route for reestablished arterial blood supply that would be necessary to facilitate the replacement of scar tissue by newly‐formed cardiac muscle.Support or Funding InformationNew Jersey Health Foundation

Pre-Clinical Investigation of Keratose as an Excipient of Drug Coated Balloons.

Background: Drug-coated balloons (DCBs), which deliver anti-proliferative drugs with the aid of excipients, have emerged as a new endovascular therapy for the treatment of peripheral arterial disease. In this study, we evaluated the use of keratose (KOS) as a novel DCB-coating excipient to deliver and retain paclitaxel. Methods: A custom coating method was developed to deposit KOS and paclitaxel on uncoated angioplasty balloons. The retention of the KOS-paclitaxel coating, in comparison to a commercially available DCB, was evaluated using a novel vascular-motion simulating ex vivo flow model at 1 h and 3 days. Additionally, the locoregional biological response of the KOS-paclitaxel coating was evaluated in a rabbit ilio-femoral injury model at 14 days. Results: The KOS coating exhibited greater retention of the paclitaxel at 3 days under pulsatile conditions with vascular motion as compared to the commercially available DCB (14.89 ± 4.12 ng/mg vs. 0.60 ± 0.26 ng/mg, p = 0.018). Histological analysis of the KOS–paclitaxel-treated arteries demonstrated a significant reduction in neointimal thickness as compared to the uncoated balloons, KOS-only balloon and paclitaxel-only balloon. Conclusions: The ability to enhance drug delivery and retention in targeted arterial segments can ultimately improve clinical peripheral endovascular outcomes.

A GLP-1 Analog Liraglutide Reduces Intimal Hyperplasia After Coronary Stent Implantation via Regulation of Glycemic Variability and NLRP3 Inflammasome/IL-10 Signaling in Diabetic Swine.

ObjectiveThis study aimed to explore whether treatment with the glucagon-like peptide-1 (GLP-1) analog liraglutide reduces intimal hyperplasia after coronary stent implantation via regulation of glycemic variability, the NLRP3 inflammasome, and IL-10 in diabetic swine.MethodsFifteen pigs were divided into a diabetes mellitus (DM) group (n = 6), a DM + liraglutide treatment group (L group) (n = 6) and a sham group (n = 3). A total of 24 everolimus-eluting stents were implanted in the left anterior descending and right coronary arteries at 3 weeks. A novel continuous glucose monitoring system (GMS) was used for 2 weeks. The means and standard deviations (SDs) were measured and calculated by the GMS. At 22 weeks, the lumen area (LA), neointimal thickness (NIT), neointimal area (NIA), and percent area stenosis (%AS) were analyzed by optical coherence tomography. Plasma tumor necrosis factor-α, interleukin-6, and interleukin-10 were assayed by ELISA. The intima protein expression levels of NLRP3, interleukin-1β, interleukin-18 and interleukin-10 were examined using Western blot analysis. Histology was used to evaluate the healing response. In an in vitro study, THP-1 cells were divided into control, high glucose (HG), HG + liraglutide, and HG + liraglutide + Exe(9–39) (a GLP-1 receptor inhibitor) groups.ResultsThe L group had a lower SD, NIT, NIA, and %AS; a larger LA; reduced inflammation and injury scores; lower expression levels of tumor necrosis factor-α, interleukin-6, NLRP3, interleukin-1β, and interleukin-18; and higher expression of interleukin-10 compared with those of the DM group (p < 0.05). In the in vitro study, similar results were obtained in the HG + liraglutide group, and Exe(9–39) abolished the effect of liraglutide (p < 0.05).ConclusionsLiraglutide treatment reduces intimal hyperplasia after stent implantation via regulation of glycemic variability, the NLRP3 inflammasome, and IL-10 in diabetic pigs in a GLP-1 receptor-dependent manner. Reducing the inflammation induced by glycemic variability may be one of the cardioprotective mechanisms of liraglutide.

Efficacy of Zotarolimus-Eluting Stents in Treating Diabetic Coronary Lesions: An Optical Coherence Tomography Study.

Diabetes mellitus (DM) plays an important role in restenosis and late in-stent thrombosis (ST).The current study using optical coherence tomography (OCT) aims to compare target lesion neointima in patients with or without diabetes after zotarolimus-eluting stent (ZES) treatment. OCT images of 90,212 struts and quantitative coronary angiography (QCA) in 62 patients (32 with DM and 30 without DM) with 69 de novo coronary lesions (34 DM and 35 non-DM) both after ZES implantation and 12 ± 1month angiographic follow-up were recorded. Patient characteristics, lesion characteristics, clinical outcomes, and OCT findings including neointimal thickness, coverage, malapposition, and intimal morphology were analyzed. Baseline patient characteristics and lesion characteristics data were similar between the two groups. Higher neointimal thickness (0.14 ± 0.09mm vs. 0.09 ± 0.04mm, p = 0.021), more neovascularization (3.03 ± 6.24 vs. 0.52 ± 1.87, p = 0.017) and higher incidence of layered signal pattern (12.19 ± 19.91% vs. 4.28 ± 9.02%, p = 0.049) were observed in diabetic lesions comparing with non-diabetic lesions. No differences were found in malapposition, uncovered percentage, and thrombus between the two groups (all p > 0.05). Occurrence of clinical adverse events was also similar during the follow-up period (p > 0.05). Although more neointimal proliferation and more neovascularization were found in diabetic coronary lesions whencompared with non-diabetic lesions, treatment with ZES showed similar stent malapposition rate at 1-year follow-up. The data indicated that ZES treatment could possibly beeffective in treating diabetic coronary lesions. ClinicalTrials.gov identifier, NCT01747356.

Hyaluronic acid-heparin conjugated decellularized human great saphenous vein patches decrease neointimal thickness.

Although the science of implantable materials has advanced therapeutic options in vascular surgery, graft failure is still a problem in need of a durable solution. With the development of coating and decellularization techniques, coated prosthetic grafts have become an option; however, whether decellularized human saphenous vein can be conjugated and implanted is not known. Human great saphenous vein (GSV) was harvested and decellularized and hyaluronic acid (HA)-heparin was conjugated to the GSV; water contact angles (WCA), morphology, and sulfur element change were measured before and after heparin bonding. GSV patches were implanted into the rat inferior vena cava and aorta; patches were harvested (Day 14) and analyzed. HA-heparin was successfully conjugated to the decellularized human GSV with altered morphology and reduced WCA. The HA-heparin coated decellularized GSV patch was anti-thrombotic in vitro, and significantly decreased neointimal thickness both in patch venoplasty and angioplasty in a rat model. Both CD90 and nestin positive cells participated in neointima formation. These data show that HA-heparin coated human GSV patches decrease neointimal thickness when used both in venoplasty and arterioplasty. Tissue engineered decellularized human GSV is a promising vascular prosthesis.

Effect of resveratrol combined with atorvastatin on re-endothelialization after drug-eluting stents implantation and the underlying mechanism

AimsTo explore whether the combination of atorvastatins and resveratrol is superior to each individual drug alone regarding re-endothelialization after drug-eluting stents (DESs) implantation. Materials and methodsNinety-four rabbits were randomized into control, atorvastatin, resveratrol, and combined medication groups. Abdominal aorta injury was induced via ballooning, followed by DES implantation. Neointimal formation and re-endothelialization after stent implantation were assessed via optical coherence tomography and scanning electron microscopy. The effects of resveratrol and atorvastatin on bone marrow-derived mesenchymal derived stem cells (BMSCs) were assessed. Key findingsCompared with the findings in the resveratrol and atorvastatin groups, the neointimal area and mean neointimal thickness were greater in the combined medication group, which also exhibited improved re-endothelialization. Compared with the effects of monotherapy, combined treatment further protected BMSCs against rapamycin-induced apoptosis and improved cell migration. Combined medication significantly upregulated Akt, p-Akt, eNOS, p-eNOS, and CXCR4 expression in BMSCs compared with the effects of monotherapy, and these effects were abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. SignificanceThe combination of atorvastatin and resveratrol has the potential of accelerating re-endothelialization after stent implantation, reducing the risk of thrombosis and improving the safety of DESs.

Sugen-morphine model of pulmonary arterial hypertension.

Pulmonary arterial hypertension is a fatal disease associated with pulmonary vascular remodeling and right ventricular hypertrophy. Pre-clinical animal models that reproduce the human pulmonary arterial hypertension process and pharmacological response to available therapies are critical for future drug development. The most prevalent animal model reproducing many aspects of angioobliterative forms of pulmonary arterial hypertension is the rat Sugen/hypoxia model in which Sugen, a vascular endothelial growth factor receptor antagonist, primarily causes initiation of endothelial injury and later in the presence of hypoxia promotes proliferation of apoptosis-resistant endothelial cells. We previously demonstrated that exposure of human pulmonary microvascular endothelium to morphine and HIV-proteins results in initial apoptosis followed by increased proliferation. Here, we demonstrate that the double-hit of morphine and Sugen 5416 (Sugen–morphine) in rats leads to the development of pulmonary arterial hypertension with significant medial hypertrophy of pre-acinar pulmonary arteries along with neo-intimal thickening of intra-acinar vessels. In addition, the pulmonary smooth muscle and endothelial cells isolated from Sugen–morphine rats showed hyperproliferation and apoptotic resistance, respectively, in response to serum starvation. Our findings support that the dual hit model of Sugen 5416 and morphine provides another experimental strategy to induce significant pulmonary vascular remodeling and development of severe pulmonary arterial hypertension pathology in rats without exposure to hypoxia.

Toll-like receptor 2-deficiency on bone marrow-derived cells augments vascular healing of murine arterial lesions

AimsNeointimal hyperplasia contributes to arterial restenosis after percutaneous transluminal coronary angioplasty or vascular surgery. Neointimal thickening after arterial injury is determined by inflammatory processes. We investigated the role of the innate immune receptor toll-like receptor 2 (TLR2) in neointima formation after arterial injury in mice. Materials and methodsCarotid artery injury was induced by 10% ferric chloride in C57Bl/6J wild type (WT), TLR2 deficient (B6.129-Tlr2tm1Kir/J, TLR2−/−) and WT mice treated with a TLR2 blocking antibody. 21 days after injury, carotid arteries were assessed histomorphometrically and for smooth muscle cell (SMC) content. To identify the contribution of circulating cells in mediating the effects of TLR2-deficiency, arterial injury was induced in WT/TLR2−/−-chimeric mice and the paracrine modulation of bone marrow-derived cells from WT and TLR2−/− on SMC migration compared in vitro. Key findingsTLR2−/− mice and WT mice treated with TLR2 blocking antibodies exhibited reduced neointimal thickening (23.7 ± 4.2 and 6.5 ± 3.0 vs. 43.1 ± 5.9 μm, P < 0.05 and P < 0.01), neointimal area (5491 ± 1152 and 315 ± 76.7 vs. 13,756 ± 2627 μm2, P < 0.05 and P < 0.01) and less luminal stenosis compared to WT mice (8.5 ± 1.6 and 5.0 ± 1.3 vs. 22.4 ± 2.2%, both P < 0.001n = 4–8 mice/group). The phenotypes of TLR2−/− vs. WT mice were completely reverted in WT/TLR2−/− bone marrow chimeric mice (5.9 ± 1.5 μm neointimal thickness, 874.2 ± 290.2 μm2 neointima area and 2.7 ± 0.6% luminal stenoses in WT mice transplanted with TLR2−/− bone marrow vs. 23.6 ± 5.1 μm, 3555 ± 511 μm2 and 12.0 ± 1.3% in WT mice receiving WT bone marrow, all P < 0.05, n = 6/group). Neointimal lesions of WT and WT mice transplanted with TLR2−/− bone marrow chimeric mice showed increased numbers of SMC (10.8 ± 1.4 and 12.6 ± 1.4 vs. 3.8 ± 0.9 in TLR2−/− and 3.5 ± 1.1 cells in WT mice transplanted with TLR2−/− bone marrow, all P < 0.05, n = 6). WT bone marrow cells stimulated SMC migration more than TLR2-deficient bone marrow cells (1.7 ± 0.05 vs. 1.3 ± 0.06-fold, P < 0.05, n = 7) and this effect was aggravated by TLR2 stimulation and diminished by TLR2 blockade (1.1 ± 0.03-fold after stimulation with TLR2 agonists and 0.8 ± 0.02-fold after TLR2 blockade vs. control treated cells defined as 1.0, P < 0.05, n = 7). SignificanceTLR2-deficiency on hematopoietic but not vessel wall resident cells augments vascular healing after arterial injury. Pharmacological blockade of TLR2 may thus be a promising therapeutic option to improve vessel patency after iatrogenic arterial injury.