Results for “Microvessels”

PubMed2026

Effect of Bariatric Surgery on Improvement of Retinal Microvasculature in Patients With Obesity: A Systematic Review and Meta-Analysis.

Obesity is associated with adverse retinal microvascular changes, including narrower central retinal arteriolar equivalent (CRAE), wider central retinal venular equivalent (CRVE) and lower arteriovenous ratio (AVR). Although bariatric surgery improves cardiometabolic risk, its effect on retinal microvascular calibre remains uncertain. We systematically searched the Cochrane Library, PubMed, ScienceDirect and Scopus up to June 2026. Prospective cohort studies reporting CRAE, CRVE or AVR before and after bariatric surgery in patients with obesity were included. Risk of bias was assessed using the Newcastle-Ottawa Scale. Pooled mean differences (MD) with 95% confidence intervals (CI) were calculated using a random-effects model. Eight prospective cohort studies including 283 patients were included. Seven studies contributed to the CRAE and CRVE analyses, and seven contributed to the AVR analysis. Bariatric surgery was associated with a significant increase in CRAE (MD = +4.02 μm, CI [0.26-7.78], p = 0.04). Sensitivity analysis excluding one study showed a stronger and more consistent effect (MD = +5.41 μm, CI [4.59-6.22], p < 0.01). CRVE significantly decreased after surgery (MD = -6.75 μm, CI [-7.42 to -6.07], p < 0.01), while AVR significantly increased (MD = +0.03, CI [0.02-0.05], p < 0.01). Sensitivity analyses suggested that the direction of effect was generally robust, although between-study heterogeneity was present. Bariatric surgery may be associated with favourable retinal microvascular changes in patients with obesity, reflected by increased CRAE and AVR and decreased CRVE.

Humans↗

PubMed2026

Adaptive proteomic remodeling and eNOS upregulation in luminal endothelium and perivascular adipose tissue of patent saphenous vein grafts after CABG.

OBJECTIVE: Long-term patency of saphenous vein grafts (SVGs) remains a significant challenge in coronary artery bypass grafting (CABG). The biological factors underlying successful human grafts are poorly understood. We aimed to characterize the structural and molecular features associated with successful graft function. METHODS: Patent and occluded SVG and internal thoracic artery (ITA) grafts were obtained from explanted hearts of CABG patients undergoing heart transplantation for end-stage heart failure not attributable to graft failure, along with freshly harvested ITA and SVG controls. Samples underwent histomorphological analysis, immunohistochemistry (IHC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics. RESULTS: Patent ITA (ITA-P) showed minimal intimal hyperplasia with medial reinforcement, whereas patent SVGs (SVG-P) had organized, α-smooth muscle actin (αSMA)-positive myofibroblast-rich neointima. Endothelial nitric oxide synthase (eNOS) was markedly upregulated in patent grafts at two sites-the luminal endothelium and adventitial microvessels within perivascular adipose tissue (PVAT)-and lost at both sites in occluded SVG (SVG-O). Adventitial CD31-positive microvessels were significantly increased in patent grafts. Proteomically, ITA-P and SVG-P shared a largely common adaptive proteome enriched in translation, RNA processing, and extracellular matrix (ECM) organization, with shared upstream activation of NR4A3, EGFR, and STAT1, and conduit-specific signatures (IGF-1/RUNX2 in ITA-P; RETN/SRC/PTGES in SVG-P). PTGES was strongly expressed in the adventitia of SVG-P. CONCLUSIONS: Patent arterial and venous bypass grafts exhibited a shared adaptive phenotype characterized by dual-site upregulation of eNOS in both the luminal endothelium and the perivascular microvessels/PVAT. In SVG-P, PTGES was co-upregulated alongside eNOS, indicating a mechanistic link between the proteomic and IHC findings. These findings highlight the perivascular compartment as a site of adaptive, eNOS-associated changes in patent vein grafts.

Humans↗