Intimal Area Research Articles

Deficiency of transcription factor E4BP4 suppresses neointimal formation after vascular injury

Abstract Aim In addition to traditional risk factors such as hypertension, diabetes, and dyslipidemia, chronic inflammation is deeply involved in the onset and pathogenesis of atherosclerotic diseases. Furthermore, diurnal fluctuations are observed in the rupture of atherosclerotic plaques and the onset of myocardial infarction. There are still many patients for whom medical treatments such as statins and antihypertensive drugs do not respond adequately, and new treatment methods are expected. E4BP4 (also known as NFIL3) is a basic leucine zipper (bZIP)-type transcription factor associated with circadian rhythms and cell viability, and it has been reported that E4BP4 regulates inflammation. Therefore, to investigate how the circadian transcription factor E4BP4 which is involved in inflammation, we decided to examine the role of E4BP4 in neointimal formation after vascular injury. Methods and Results Using E4BP4-deficient (E4BP4−/−) and wild-type (WT) mice, we investigated neointimal formation 2 weeks after femoral artery injury induced by an external vascular cuff model. Intimal and medial area were measured, and the intima/media ratio was calculated. Systolic blood pressure was similar between groups (WT mice: 92 ± 5 mmHg [n = 5] vs. E4BP4−/− mice: 90 ± 4 mmHg [n = 5]). And there was no significant difference in baseline body weight between groups (WT mice: 22.4 ± 0.8 g [n = 5] vs. E4BP4−/− mice: 22.0 ± 1.1 g [n = 5]). The mean intimal area and the intima/media ratio of E4BP4−/− mice decreased by 86 % (WT mice: 3,683 ± 512 μm2 [n = 10] vs. E4BP4−/− mice: 521 ± 363 μm2 [n = 10]; P < 0.0001) and 97% (WT mice: 0.33 ± 0.05 vs. E4BP4−/− mice: 0.01 ± 0.03; P < 0.0001), compared with WT mice. However, we observed no significant difference in the medial area (WT mice: 11,019 ± 358 μm2 vs. E4BP4−/− mice: 11,281 ± 401 μm2; P = NS) between groups (Figure). Immunohistochemistry for NK cell (NKp46) revealed the percentage of NKp46 positive area in the adventitia of E4BP4−/− mice was significantly lower compared with WT mice at 14 days post-injury (P <0.05). Furthermore, the positive area of IL-6 (P<0.05), TNF-α (P<0.05) and IFN-γ (P<0.05) in the intima of E4BP4−/− mice tended to be much smaller than those of WT mice. Our findings indicate that E4BP4 might induce vascular inflammation following vascular injury. Conclusions Deficiency of E4BP4 reduced the inflammatory cytokines and suppressed neointimal formation after injury. We also observed a decrease in NKp46, suggesting that NK cell development is impaired by E4BP4 deficiency. The present study is the first to demonstrate that E4BP4 plays an important role in the increase of neointimal formation after injury in vivo, thus suggesting that E4BP4 inhibition may represent a useful strategy to inhibit vascular inflammation.Neointimal formation after cuff injury

Diesel exhaust particles activate macrophages and IRF5 expression in atherosclerosis

Abstract Introduction Over 20% of global deaths related to cardiovascular disease have been attributed in part to air pollution, particularly fine particulate matter (PM2.5) (1). In highly trafficked urban areas, smaller ultrafine diesel exhaust particles (DEP) represent a significant proportion of PM2.5. DEP is associated with the progression of atherosclerosis and increased plaque susceptibility to rupture (2). We have previously shown that interferon regulatory factor 5 (IRF5) has a key role in necrotic core formation, a distinguishing feature of vulnerable atherosclerotic plaques, by rendering macrophages defective at efferocytosis (3). Pronounced elevation of IRF5 is also seen in symptomatic carotid plaques, particularly in the rupture-prone shoulder regions (4). Purpose We examined the effect of DEP on macrophage phenotype and IRF5 expression in atherosclerosis. Methods Bone marrow-derived macrophages (BMDMs) from C57BL/6 mice, differentiated with GM-CSF (to mimic inflammatory macrophages) or M-CSF (mimicking homeostatic resident macrophages) were incubated with PBS or DEP (10 µg/mL) in vitro for 18 hours. Expression of inflammatory cytokines (IL-6, IL-12α), macrophage polarisation markers CD11c (itgax, inflammatory) and CD206 (mrc1, resident anti-inflammatory) and IRF5 was quantified by real-time PCR. In addition, high fat-fed ApoE-/- mice were exposed to saline or DEP (35 µL at 1 mg/mL) twice weekly for 5 weeks by pulmonary administration. The pan-macrophage marker CD64, CD206 and IRF5 were quantified in paraffin-embedded sections of brachiocephalic artery lesions by immunohistochemistry. Results In M-CSF-differentiated murine macrophages incubated with DEP, significant fold increases in gene expression (relative to PBS control) were observed: IRF5 (1.4-fold), IL-6 (31.5-fold) and IL-12α (5.8-fold) while CD206 (0.8-fold) decreased (Figure 1a, n = 5, p<0.05, two-tailed paired t-tests). CD11c expression was unchanged. No statistically significant differences were detected in GM-CSF-differentiated macrophages. In the brachiocephalic arteries of DEP-exposed ApoE-/- mice we observed increases in CD64+ macrophages (28.2±7.4 vs 15.5±5.6) and IRF5 (16.6±3.6 vs 10.1±3.4) expression, while CD206 expression decreased (4.1±0.9 vs 11.0±1.2) in comparison to saline-exposed mice (Figure 1b mean±SD, n = 5, p<0.05, two-tailed unpaired t-tests, data expressed as % of intima area). Conclusion DEP promotes CD64+ macrophages and IRF5 expression in murine atherosclerosis, while inflammation and IRF5 is induced in vitro, but only in M-CSF-differentiated murine BMDMs. This suggests that DEP has no impact on inflammatory macrophages but could switch homeostatic resident macrophages to a more inflammatory phenotype via the activation of IRF5. Therefore, IRF5 is a promising candidate for further investigation into the initial macrophage response to inhaled particles that leads to the exacerbation of vascular disease.

Simulation analysis of different types of balloon dilatation catheters for the treatment of intracranial arterial stenosis.

The application of balloon dilation catheters in the management of intracranial arterial stenosis has been gradually increasing. However, studies on the feasibility and effectiveness of different types of balloons remain relatively scarce. In this study, catheter models of three different materials were designed to simulate balloon crimping,splitting, and dilatation processes. A compliant balloon produces large deformations with poor dilatation and a stress concentration phenomenon. During dilatation, the shear stress generated in the intima and lesion area by the semi-compliant balloon was smaller than that generated by the non-compliant balloon. These results demonstrate the feasibility of using semi-compatible balloons.

Correlation between preoperative cephalic vein pathological types and autogenous arteriovenous fistula (AVF) maturation in patients with stage 5 chronic kidney disease.

To explore the correlation between preoperative cephalic vein pathological types and the maturation of autogenous arteriovenous fistula (AVF) in patients with chronic kidney disease (CKD), providing new ideas and methods for clinical prediction of fistula maturation. A retrospective analysis was performed in 80 patients who underwent AVF creation surgery from June 2021 to June 2023 at our hospital. Patients were followed up for 6 months. Patients were classified into the mature group (n = 57) and the power loss group (n = 23) based on the AVF maturation status. Preoperative excised venous tissues were examined using Masson's trichrome staining to compare the intimal area (Ia), medial area (Ma), lumen diameter (Ld), average intimal thickness (Avg It), and average medial thickness (Avg Mt), along with the calculations and comparisons of Ia/Ma, Avg It/Avg Mt ratios. Factors influencing AVF power loss were identified using the multifactorial logistic regression analysis. Ia, Ia/Ma, and Ld were lower in the power loss group compared to the mature group (P < 0.01). No significant difference was found in Avg Mt and Avg It/Avg Mt levels between the two groups (P > 0.05). The level of Avg It was higher in the power loss group (P < 0.05). Avg It was a risk factor (P < 0.001), while Ld was a protective factor for AVF power loss (P < 0.05). The levels of Avg It and Ld in preoperative cephalic vein tissue before AVF formation were correlated with AVF power loss. Early monitoring may improve therapeutic outcomes and prognosis of patients with stage 5 CKD.

Arterial Histology in Amputated Limbs with Chronic Limb-Threatening Ischemia and Cadaver Limbs

ObjectiveThe study objectives were to 1) elucidate the histopathological and structural alterations in the femoral to popliteal arteries and tibial or more distal arteries in patients with chronic limb-threatening ischemia through detailed histomorphological and histopathological examinations of the lower limb arteries in the amputated limbs; and 2) elucidate the basic structure of the entire lower extremity, from the external iliac artery to the digital artery, based on histomorphological examinations of cadaver limbs. MethodsWe examined the histopathology and histomorphology of lower limb arteries harvested from 22 amputated limbs and that from 11 cadavers without lower limb issues. Sixty-three sections from the amputated limbs were categorized into femoropopliteal, tibial, and distal segments. Five hundred ten sections (from the external iliac artery to the digital artery) from the cadavers were categorized as femoropopliteal segments, tibial and distal segments, and others. The modified American Heart Association classification was used for the histopathological analysis, and the advanced lesion was defined as the presence of progressive atherosclerotic lesion. In the histomorphological analyses, we calculated %stenosis, %medial area as the medial area divided by the area within the external elastic lamina × 100, and %intimal area as the intimal area divided by the area within the external elastic lamina × 100. ResultsIn amputated limbs, advanced lesions and calcification in the medial area were more prevalent in the femoropopliteal segments than in the tibial and distal segments (advanced lesion: 8/10 vs. 18/42, p=0.048; calcification: 10/10 vs. 28/42, p=0.037), while %stenosis and prevalence of luminal thrombi were comparable. Significant inverse correlations were noted between %medial area and external elastic lamina diameter in both amputated (r=-0.641, p<0.001) and cadaver limbs (r=-0.775, p<0.001). In the femoropopliteal segments of the amputated limbs, luminal stenosis was solely caused by intimal lesions, whereas in the tibial and distal segments, medial area thickening contributed to luminal stenosis when intimal lesions were less pronounced. When the external elastic lamina diameter was entered as a covariate, the medial area of the 178 cadaver tibial and distal segments with minimal intimal lesions (<40% intimal area) was significantly greater when >75% stenosis was present in the femoropopliteal segments (p<0.001). ConclusionAdvanced lesions in the tibial and distal segments are less prevalent compared to the femoropopliteal segments. Medial area thickening may contribute to luminal stenosis in the tibial and distal segments when intimal lesions were less pronounced, which may be secondary to a significant proximal occlusive lesion.

Smooth muscle cells clonally expand in a murine carotid allograft model complicated by immune reactions to reporter transgenes

Background and aimsMost experimental studies of allograft vasculopathy (AV) have relied on transplantation between major histocompatibility complex-mismatched inbred mouse strains, but this leads to the complete eradication of donor smooth muscle cells (SMCs) and lesions formed by recipient cells. This is unlike human AV which is thought to form mainly by donor SMCs. Here, we studied sources of neointimal cells in a minor histocompatibility antigen-mismatched AV model by combining male-to-female orthotopic carotid transplantations and lineage tracing by SMC-specific expression of fluorescent proteins. MethodsTo track SMC-derived cells in allograft vasculopathy, we used male donor mice with SMC-restricted Cre recombination of the mT/mG reporter transgene, which switches expression of membrane-bound red fluorescent protein (RFP) to green fluorescent protein (GFP), or the stochastically recombining Confetti reporter transgene, which yields a mosaic expression of four fluorescent proteins. Donor carotid segments were harvested and orthotopically allografted to female recipients that were wildtype or had non-recombined reporter transgenes. Inhibition of T cell responses by CTLA4Ig was used in some experiments. Sections of lesions harvested after 4 weeks were analyzed by fluorescence microscopy. ResultsDonor-derived SMCs survived and gave rise to part of the neointimal cells in experiments where carotid segments from recombined mT/mG male mice were transplanted into wild-type or non-recombined mT/mG female mice. Sex-mismatched transplants developed significant lesions, increasing the intimal and medial area 4.6-fold (p = 0.038) and 2.0-fold (p = 0.024) compared to sex- and fluorescence-matched controls, respectively. Interestingly, sex-matched fluorescence-positive transplants developed intimal lesions in 50% of fluorescence-naïve recipient controls. To study the clonal structure of the neointimal donor-derived SMC lineage cells, we then transplanted male carotids with heterozygous or homozygous recombined Confetti transgenes into female recipients. These transplants developed lesions with few surviving donor SMCs, indicating that expression of the Confetti reporter increased rejection and donor-specific SMC death. Some of the few remaining donor SMCs underwent clonal expansion. CTLA4Ig administration at the time of surgery did not improve SMC survival in mT/mG or Confetti transplants. ConclusionMale-to-female transplant models feature donor-derived SMCs, some of which undergo clonal expansion, but immune rejection to fluorescence reporters appears to bias results in lineage tracing models. Overcoming these challenges with alternative reporter transgenes or tolerant recipients is necessary to study the mechanisms by which donor SMCs contribute to allograft vasculopathy.

An arteriovenous fistula model: Carotid artery-posterior facial vein fistula in rats.

To describe an alternative arteriovenous fistula (AVF) model involving anastomosis of the common carotid artery (CCA) with the posterior facial vein (PFV). Twenty-two male Sprague-Dawley rats (age 6-8 weeks) were used to establish the AVF model involving end-to-side anastomosis of PFV and CCA. The peak velocity of the CCA and the diameter of the outflow vein were recorded at 7, 14, and 42 days after the operation using Doppler ultrasound. Pathological examination of the intimal lesions was performed at 14 and 42 days after operation. One rat died within 24 h after surgery related to anesthesia. The patency rates at days 7, 14, and 42 were 85.7%, 81%, and 81%, respectively. The diameter of the carotid artery in rats is approximately 0.8 mm. The diameter of the outflow vein was increased by 1.7-fold and 2.2-fold at 7 days (1.1 ± 0.118 mm) and 14 days (1.4 ± 0.073 mm). At 42 days (1.96 ± 0.101 mm) after operation, the diameter was 3-fold greater compared to the unoperated control rat. The peak systolic flow velocity of the carotid artery at 7 days (593 ± 17.36 mm/s) and 14 days (767 ± 13.64 mm/s) after surgery was significantly greater compared to the control rat (314 ± 15.13 mm/s). The rate of increase was fastest at 7 days and leveled off from 14 to 42 days (875 ± 26 mm/s) after surgery. At 14 days, the intima area showed a nearly 50-fold increase (230 ± 9.93 μm2 × 103) compared to control (area 5 ± 0.37 μm2 × 103). Comparing 6 weeks with 2 weeks (280 ± 10.54 μm2 × 103) after surgery, the intima area increased 1.2 times. The CCA-PFV fistula in rats is a viable alternative AVF model.

Proteomics early after heart transplantation and relation to coronary intimal changes and prognosis

BackgroundLong-term survival after heart transplantation (HTx) is limited by cardiac allograft vasculopathy (CAV). The pathogenesis of CAV is poorly understood, and treatment has not yet been well-established. In this exploratory study, we aimed to identify novel immune and non-immune biomarkers correlated to CAV development, and biomarkers predicting CAV related events. MethodsUsing a proteomic panel, 92 cardiovascular disease-related proteins were evaluated in 26 de novo HTx patients at 3- and 12-months post transplantation. Intima area changes were assessed using optical coherence tomography (OCT). Major adverse cardiac events (MACE) included significant CAV progression, heart failure, and cardiovascular death. ResultsMedian follow up was 6.8 years. We found changes in four inflammatory biomarkers: Matrix metalloproteinase 3 (MMP-3) and matrix metalloproteinase 2 (MMP-2) were significantly increased after 3 months in the group of patients with highest intima proliferation, and after 12 months in patients experiencing MACE, respectively. Monocyte chemotactic protein 1 (MCP-1) was increased after 12 months in patients experiencing MACE. Platelet derived growth factor subunit A (PDGF-A) was significantly increased after 3 months in the group of patients with highest intima proliferation. ConclusionsWe identified four biomarkers that may be associated with CAV development which differed significantly between groups of intima proliferation and MACE; MMP-2, MMP-3, MCP-1 and PDGF-A. Further studies are needed to examine whether our findings offer the basis to seek for new markers of graft vasculopathy or treatment options.

Regular transient limb ischemia improves endothelial function and inhibits endothelial cell apoptosis to prevent atherosclerosis in rabbit

AimsRegular transient limb ischemia (RTLI) can prevent atherosclerosis (AS) progression in hypercholesterolemic rabbits. This study aimed to investigate the minimum effective intensity and possible mechanisms of RTLI for preventing atherosclerosis.MethodsEighty rabbits were divided into eight groups: normal (N), high cholesterol (H), three RTLI [three RTLI cycles every other day (R3qod), three RTLI cycles daily (R3qd), and six RTLI cycles daily (R6qd), each cycle of RTLI included 5 min of limb ischemia followed by 5 min limb reperfusion], and three correlated sham RTLI [sham ischemia for 30 min once every other day (S3qod), sham ischemia for 30 min once daily (S3qd), and sham ischemia for 60 min once daily (S6qd)]. Rabbits in group N were kept normally, while the others were fed 1% cholesterol diet for 12 weeks. The RTLI and sham RTLI groups were received RTLI or sham RTLI procedure, respectively. The plaque area in the thoracic aorta was determined by oil red O staining, and quantifying the ratio of plaque area to intimal area (PA/IA). Endothelium-dependent and -independent relaxation were also determined. Endothelial cell were isolated from abdominal aorta of rabbits, and the apoptosis ratio was detected using flow cytometry.ResultsThe PA/IA and early apoptotic cell ratio was significantly lower as well as the endothelium-dependent relaxation response was higher in group R6qd than those in groups H and S6qd, while those in the R3qod group was not significantly different from those in groups H and S3qod, as well as those in the R3qd group showed no significant difference compared to those in groups H and S3qd.ConclusionsSix cycles of RTLI daily was the optimal effective intensity to prevent AS progression in rabbits. Endothelial function improvement and apoptosis inhibition might contribute to the anti-AS effects.

Role of C/EBP Homologous Protein in Vascular Stenosis After Carotid Artery Injury.

The study aims to explore the fluctuating expression of C/EBP Homologous Protein (CHOP) following rat carotid artery injury and its central role in vascular stenosis. Using in vivo rat carotid artery injury models and in vitro ischemia and hypoxia cell models employing human aortic endothelial cells (HAECs) and vascular smooth muscle cells (T/G HA-VSMCs), a comprehensive investigative framework was established. Histological analysis confirmed intimal hyperplasia in rat models. CHOP expression in vascular tissues was assessed using Western blot and immunohistochemical staining, and its presence in HAECs and T/G HA-VSMCs was determined through RT-PCR and Western blot. The study evaluated HAEC apoptosis, inflammatory cytokine secretion, cell proliferation, and T/G HA-VSMCs migration through Western blot, ELISA, CCK8, and Transwell migration assays. The rat carotid artery injury model revealed substantial fibrous plaque formation and vascular stenosis, resulting in an increased intimal area and plaque-to-lumen area ratio. Notably, CHOP is markedly elevated in vessels of the carotid artery injury model compared to normal vessels. Atorvastatin effectively mitigated vascular stenosis and suppresses CHOP protein expression. In HAECs, ischemia and hypoxia-induced CHOP upregulation, along with heightened TNFα, IL-6, caspase3, and caspase8 levels, while reducing cell proliferation. Atorvastatin demonstrated a dose-dependent suppression of CHOP expression in HAECs. Downregulation of CHOP or atorvastatin treatment led to reduced IL-6 and TNFα secretion, coupled with augmented cell proliferation. Similarly, ischemia and hypoxia conditions increased CHOP expression in T/G HA-VSMCs, which was concentration-dependently inhibited by atorvastatin. Furthermore, significantly increased MMP-9 and MMP-2 concentrations in the cell culture supernatant correlated with enhanced T/G HA-VSMCs migration. However, interventions targeting CHOP downregulation and atorvastatin usage curtailed MMP-9 and MMP-2 secretion and suppressed cell migration. In conclusion, CHOP plays a crucial role in endothelial injury, proliferation, and VSMCs migration during carotid artery injury, serving as a pivotal regulator in post-injury fibrous plaque formation and vascular remodeling. Statins emerge as protectors of endothelial cells, restraining VSMCs migration by modulating CHOP expression.

The Role of Matrix Metalloproteinases in Thoracic Aortic Disease: Are They Indicators for the Pathogenesis of Dissections?

The pathogenesis of aortic aneurysm and dissection continues to be under discussion. Extracellular matrix (ECM) remodeling processes in the aortic wall are hypothesized to be involved in the development of the disorders. Therefore, in a histological study, we investigated the expression of metalloproteases 1 and 9 (MMP1 and MMP9) and their inhibitors (TIMP 1 and TIMP 2) in cardiac surgery patients. In parallel, we studied the aortic roots by echocardiography. Clinical reports of 111 patients (30 women and 81 men) who suffered from aortic aneurysms and aortic dissection were evaluated and studied by transesophageal echocardiography. Seven patients who had coronary heart disease served as "healthy controls". All patients underwent the necessary surgical procedure according to the diagnosed aortic disease in the period from 2007 to 2015. A tissue sample of the aortic biopsies was collected from each patient during surgery. Immunohistochemical staining was performed for MMP1 and MMP9 and TIMP1 and TIMP2 as well. Vascularization was monitored by a CD 31 antibody. In direct comparison, the expressions are not homogeneous. We found the smallest changes in the intima area at all. TIMP 1 and TIMP 2 distribution increases from the lumen of the vessel outward in the wall layers of the aorta. In the case of arteriosclerotic changes, intima had a capillarization, but not in the media. An opposite pattern was found in the dissected aortas. There are differences in the vascularization between the aneurysm and dissection and the different layers, respectively. A different remodeling process of the ECM in comparison to the vascular layers must be hypothesized. Reading the patterns of staining and with regard to the known inhibitory effect of MMP9 on ECM remodeling, but especially TIMP 2 on neoangiogenesis, disturbed nutrition, and dysfunctional vasa vasorum remodeling must be assumed as causes of dissection.

Shizukaol C alleviates trimethylamine oxide-induced inflammation through activating Keap1-Nrf2-GSTpi pathway in vascular smooth muscle cell

BackgroundCardiovascular disease is one of the main causes of global mortality, and there is an urgent need for effective treatment strategies. Gut microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) promotes the development of cardiovascular diseases, and shizukaol C, a natural sesquiterpene isolated from Chloranthus multistachys with various biological activities, might exhibit beneficial role in preventing TMAO-induced vascular inflammation. PurposeThe purpose of this study was to investigate the anti-inflammatory effects and the underlying mechanisms of shizukaol C on TMAO-induced vascular inflammation. MethodsThe effect and underlying mechanism of shizukaol C on TMAO-induced adhesion molecules expression, bone marrow-derived macrophages (BMDM) adhesion to VSMC were evaluated by western blot, cell adhesion assay, co-immunoprecipitation, immunofluorescence assay, and quantitative Real-Time PCR, respectively. To verify the role of shizukaol C in vivo, TMAO-induced vascular inflammation model were established using guidewire-induced injury on mice carotid artery. Changes in the intima area and the expression of GSTpi, VCAM-1, CD68 were examined using haematoxylin-eosin staining, and immunofluorescence assay. ResultsOur data demonstrated that shizukaol C significantly suppressed TMAO-induced adhesion molecule expression and the bone marrow-derived macrophages (BMDM) adhesion in vascular smooth muscle cells (VSMC). Mechanically, shizukaol C inhibited TMAO-induced c-Jun N-terminal kinase (JNK)-nuclear factor-kappa B (NF-κB)/p65 activation, and the JNK inhibition was dependent on the shizukaol C-mediated glutathione-S-transferase pi (GSTpi) expression. By further molecular docking and protein-binding analysis, we demonstrated that shizukaol C directly binds to Keap1 to induce Nrf2 nuclear translocation and upregulated GSTpi expression. Consistently, our in vivo experiment showed that shizukaol C elevated the expression level of GSTpi in carotid arteries and alleviates TMAO-induced vascular inflammation. Conclusion: Shizukaol C exerts anti-inflammatory effects in TMAO-treated VSMC by targeting Keap1 and activating Nrf2-GSTpi signaling and resultantly inhibits the downstream JNK-NF-κB/p65 activation and VSMC adhesion, and alleviates TMAO-induced vascular inflammation in vivo, suggesting that shizukaol C may be a potential drug for treating TMAO-induced vascular diseases.

Morphometric Analysis of Coronary Arteries: An Autopsy Study from a Tertiary Hospital at Kolar, Karnataka, India

Introduction: The incidence and prevalence of Coronary Artery Disease (CAD) are rising worldwide, particularly in India. CAD can be asymptomatic in the general population. Aim: To analyse the significance of morphometric measurements of the coronary arteries in autopsy cases of unnatural deaths. Materials and Methods: This was a retrospective cross-sectional autopsy study conducted from January to December 2020 in the Department of Pathology in collaboration with the Department of Forensic Medicine at Sri Devaraj Urs Medical College, Kolar, Karnataka, India. Cases of deaths due to unnatural causes were considered. Morphometric parameters such as Luminal Area (LA), Internal Elastic Lamina Area (IELA), External Elastic Lamina Area (EELA), width of the intima at maximal thickness, width of the media at maximal thickness, intimal area, medial area, percentage of luminal narrowing, Intimal Thickness Index (ITI), and Intima to Media Ratio (IMR) were estimated using a Zeiss microscope on Verhoeff-Van-Gieson (VVG) stained tissue sections and analysed with ZEN software. All data were entered into a Microsoft Excel spreadsheet and analysed using Statistical Package for the Social Sciences (SPSS) version 22.0. Results: A total of 80 autopsy cases were considered for the current research, of which 62 were males and 18 were females. The mean age of the cases was 37.6 years. Two cases (11.1%) among females and nine cases (14.5%) among males had asymptomatic atherosclerotic lesions in their coronary arteries. With increasing age, the percentage of asymptomatic atherosclerotic cases also increased. The p-values for the width of the intima at maximal intimal thickness and IMR were 0.005 and 0.027, respectively, between the non atherosclerotic and atherosclerotic groups. Conclusion: The morphometric parameters, such as the width of the intima at maximal intimal thickness and IMR, predict the presence of atherosclerotic lesions/CAD in the asymptomatic general population. This information can be used to implement preventive measures and inform health policy by the medical community

Cardiac allograft vasculopathy in heart transplanted recipients: The multivessel study

BackgroundCardiac Allograft Vasculopathy (CAV) is a prevailing complication following heart transplantation. We aimed to investigate if CAV causes equal vascular remodeling in the major coronary arteries using quantitative Optical Coherence Tomography (OCT) and to explore the prognostic potential of OCT derived measurements from each coronary artery. Methods64 heart transplanted patients had a combined total of 114 full three-vessel OCTs and coronary angiographies performed between 2013 and 2019. OCT pullbacks were categorized by angiographic CAV classification. Registration of disease progression was censored on July 1, 2022. ResultsOCT recordings were classified as follows: No significant CAV, n = 73; mild CAV, n = 18; moderate CAV, n = 13 and severe CAV, n = 10. From inter-coronary comparison of severe CAV, we found significant differences by both average lumen/intima ratio (p<0.0001) and average intima/media ratio (p<0.0001). The left descending artery (LAD) showed increasingly smaller luminal areas and larger intimal areas within CAV groups compared with the remaining coronary arteries. No differences were seen between major coronary arteries without significant CAV.LAD derived average intima/media ratio (HR: 3.39; 95% CI: 1.33 to 8.63; p = 0.01) and average lumen/intima ratio (HR: 2.77; 95% CI: 1.09 to 7.05; p = 0.03) were the strongest predictors of CAV progression. LAD predictions were superior to predictions based on all three coronary arteries. ConclusionsLAD derived OCT measurements were increasingly affected by CAV compared with the circumflex and right coronary artery. Average lumen/intima and intima/media ratios were the strongest predictors of CAV progression.

Effect of F11 Receptor/Junctional Adhesion Molecule-A–derived Peptide on Neointimal Hyperplasia in a Murine Model

PurposeTo determine whether inhibition of the F11 receptor/JAM-A (F11R) using F11R-specific antagonist peptide 4D results in inhibition of smooth muscle cell (SMC) proliferation and migration in vivo, known as neointimal hyperplasia (NIH), using a mouse focal carotid artery stenosis model (FCASM). Materials and MethodsThe mouse FCASM was chosen to test the hypothesis because the dominant cell type at the site of stenosis is SMC, similar to that in vascular access stenosis. Fourteen C57BL/6 mice underwent left carotid artery (LCA) partial ligation to induce stenosis, followed by daily injection of peptide 4D in 7 mice and saline in the remaining 7 mice, and these mice were observed for 21 days and then euthanized. Bilateral carotid arteries were excised for histologic analysis of the intima and media areas. ResultsThe mean intimal area was significantly larger in control mice compared with peptide 4D–treated mice (0.031 mm2 [SD ± 0.024] vs 0.0082 mm2 [SD ± 0.0103]; P = .011). The mean intima-to-intima + media area ratio was significantly larger in control mice compared with peptide 4D–treated mice (0.27 [SD ± 0.13] vs 0.089 [SD ± 0.081]; P = .0079). NIH was not observed in the right carotid arteries in both groups. ConclusionsPeptide 4D, an F11R antagonist, significantly inhibited NIH in C57BL/6 mice in a FCASM.

Safety and Efficacy of an Innovative Everolimus-Coated Balloon in a Swine Coronary Artery Model.

Drug-coated balloons have been used as a non-stenting treatment in coronary and peripheral artery disease. Until recently, only sirolimus- and paclitaxel-coated balloons have been investigated in clinical trials. We evaluated the safety and efficacy of an innovative everolimus-coated balloon (ECB) in a swine coronary artery model. thirty-two swine coronary arteries were prepared through dilatation with a non-coated angioplasty balloon in a closed-chest model. During a period of 90 days, the following four groups (four animals per group, two coronary arteries per animal) were compared for safety and efficacy: A, Rontis ECB with 2.5 μg/mm2 of drug per balloon surface; B, Rontis ECB with 7.5 μg/mm2; C, Rontis Europa Ultra bare balloon; and D, Magic Touch, Concept Medical, sirolimus-coated balloon with a drug load of 1.3 μg/mm2. Differences in local biological effects (arterial reaction scores) and surface of intimal area (mm2) were not statistically significant between the treatment groups. Numerically, group A showed the lowest intimal area and intimal mean thickness, while group B showed the lowest stenosis among all groups. ECB was safe and effective in a porcine coronary artery model. The dose of everolimus may play a role in the biocompatibility of the balloon.

Inhibitory effect of cilostazol on intimal hyperplasia and smooth muscle cell proliferation in a rabbit carotid artery anastomosis model

Objectives: This study aims to investigate the effect of cilostazol on intimal hyperplasia and smooth muscle cell proliferation in a rabbit carotid artery anastomosis model. Materials and methods: A total of 16 New Zealand male rabbits weighing 2 to 3 kg were used in this study. The rabbits were divided into two groups with eight in each group as Group A and Group B. A vertical neck incision was made in an appropriate position for all group rabbits and the right carotid artery was dissected. The same artery was transected and anastomosis using 8/0 polypropylene was performed with a continuous anastomosis technique. Group A was assigned as the control group and no medication was given. Cilostazol was administrated to Group B at a dose of 25 mg/kg twice a day per oral for 21 days. At the end of Day 21, the anastomosis segments of the right carotid artery and contralateral carotid artery of all rabbits were sent to the histology laboratory for analysis. The lumen diameter, lumen area, intimal area, medial area, and intima/media area ratio were estimated. Results: In the serial sections, the mean lumen diameter of Group B was found to be significantly higher than Group A (p=0.001). The lumen area of Group B was significantly higher than Group A (p=0.001). The section series were evaluated and the area of the intima of Group B was significantly lower than Group A (p=0.001). The medial area of Group B was significantly larger than Group A (p=0.001). The intima/media area ratio was significantly higher in Group A (p=0.001). Conclusion: Cilostazol may be useful for preventing intimal hyperplasia and smooth muscle cell proliferation after vascular surgery.

External stenting for saphenous vein grafts in coronary artery bypass grafting: A meta-analysis.

Autologous saphenous vein grafts (SVGs) are the most commonly used bypass conduits in coronary artery bypass grafting (CABG) with multivessel coronary artery disease. Although external support devices for SVGs have shown promising outcomes, the overall efficacy and safety remains controversial. We aimed to evaluate external stenting for SVGs in CABG versus non-stented SVGs. MEDLINE, EMBASE, Cochrane Library and clinicaltrails.gov were searched for randomized controlled trials (RCTs) to evaluate external-stented SVGs versus non-stented SVGs in CABG up to 31 August 2022. The risk ratio and mean difference with 95% confidence interval were analysed. The primary efficacy outcomes included intimal hyperplasia area and thickness. The secondary efficacy outcomes were graft failure (≥50% stenosis) and lumen diameter uniformity. We pooled 438 patients from three RCTs. The external stented SVGs group showed significant reductions in intimal hyperplasia area (MD: -0.78, p < 0.001, I2 = 0%) and thickness (MD: -0.06, p < 0.001, I2 = 0%) compared to the non-stented SVGs group. Meanwhile, external support devices improved lumen uniformity with Fitzgibbon I classification (risk ratio (RR):1.1595, p = 0.05, I2 = 0%). SVG failure rates were not increased in the external stented SVGs group during the short follow-up period (RR: 1.14, p = 0.38, I2 = 0%). Furthermore, the incidences of mortality and major cardiac and cerebrovascular events were consistent with previous reports. External support devices for SVGs significantly reduced the intimal hyperplasia area and thickness, and improved the lumen uniformity, assessed with the Fitzgibbon I classification. Meanwhile, they did not increase the overall SVG failure rate.

Effectiveness of Rex shunt for improving the abnormal portal hemodynamics and portal venous pathology in EHPVO animal model.

To investigate the feasibility of the re-patent EHPVO (r-EHPVO) as an animal model of Rex shunt and the effectiveness of Rex shunt in improving abnormal portal hemodynamics and portal venous pathology of EHPVO. A total of 18 New Zealand white rabbits were randomly divided into three groups: normal control (NC) group, extrahepatic portal venous obstruction (EHPVO) group, and r-EHPVO group. The main portal vein was dissected only in the NC group. The main portal vein was narrowed by a cannula in the EHPVO group. The cannula narrowing the main portal vein was removed to restore the portal blood flow into the liver on day 14 in the r-EHPVO group. The portal pressure, splenic size, blood flow velocity, and diameter of the portal vein were measured on days 14 and 28. The shear stress (SS) and circumferential stress (CS) of the portal vein were calculated. The proximal end of the main portal vein was collected on day 28 for further pathological analysis, and the thickness and area of the intima and media were measured by Image J software. The portal pressure, splenic size, SS, CS, intima and media thickness, the ratio of intimal to medial area (I/M), and the ratio of intimal area to the sum of intimal and medial area (I/I + M) were compared among the three groups. The correlation between SS and intimal thickness and between CS and medial thickness were analyzed. On day 28, the portal pressure of the EHPVO group was significantly higher than that of the NC and r-EHPVO groups, but no significant difference was detected in the portal pressure between r-EHPVO and NC groups. The length and thickness of the spleen in the EHPVO and r-EHPVO groups were significantly higher than those in the NC group (P < 0.01) but were significantly lower in the r-EHPVO group than those in the EHPVO group (P < 0.05). The SS was significantly lower in the EHPVO group than in NC and r-EHPVO groups (P < 0.05) but was significantly higher in the NC group than in the r-EHPVO group (P = 0.003). The CS was significantly higher in the EHPVO and r-EHPVO groups than that in the NC group (P < 0.05) but was significantly lower in the r-EHPVO group than that in the EHPVO group (P < 0.001). The intimal thickness, I/M, and I/I + M of the EHPVO group were significantly higher than those of the NC and r-EHPVO groups (P < 0.05), but no significant difference was observed between the NC and r-EHPVO groups (P > 0.05). The SS is negatively related to intimal thickness (r = - 0.799, P < 0.001). The r-EHPVO model is feasible as an animal model of the Rex shunt. The Rex shunt could be beneficial to improving the abnormal portal hemodynamic and portal venous intimal hyperplasia by restoring the portal blood flow into the liver.

Optimization of a local type rabbit model for arteriovenous fistula, focused on study neointimal hyperplasia

Link of Video Abstract: https://youtu.be/8kcI8mX5A6Y Background: Hemodialysis vascular access dysfunction is a significant cause of morbidity and mortality in hemodialysis patients. Over the past decades, numerous animal models have been developed. However, there needs to be more animal model protocol with rabbits to investigate neointimal hyperplasia in the arteriovenous fistula. This study aimed to explore an alternative rabbit model using a wild-type local model for investigating neointimal hyperplasia in the arteriovenous fistula. Methods: One local-type male rabbit performed arteriovenous fistula, in which the right carotid communis artery was anastomosed end-to-side to the right internal jugular vein. When examining vascular tissue, measurements were taken of the thicknesses of the tunica intima and tunica media, as well as the areas of the tunica intima and tunica media, vascular diameters, and vascular lumen areas. Result: We successfully induced neointimal hyperplasia in local-type rabbits, indicated by increased tunica intima thickness after 28 days of the arteriovenous fistula procedure. Conclusion: Optimation of the Rabbit model using a wild-type local model for investigating neointimal hyperplasia in arteriovenous fistula may be susceptible and considered as it is accessible and cost-effective besides producing the same outcome as a laboratory rabbit