The resistance of internal mammary artery (IMA) toward atherosclerosis is not well understood. In plasma, homocysteine (Hcy) occurs in reduced, oxidized, homocysteine thiolactone and a component of proteins as a result of N- or S-homocysteinylation. We evaluated S/N-homocysteinylated protein levels in IMA fragments of patients undergoing coronary artery bypass grafting, and whether they were affected by genetic common variants. We tested whether tHcy, Hcy-S-protein levels, genotypes or Hcy-induced methylation modifications were related to differences in iNOS, Ddah2, and eNOS gene expression between territories. A small percentage of Hcy-S-proteins were found in IMA fragments. The Mthfr C677T (rs1801133) and Pon-1 Leu55Met (rs854560) variants were associated with Hcy-S-proteins. We observed a gradual difference according to Hcy-S-protein levels in the methylation degree of the Ddah2 gene promoter in aortic, but not in IMA, fragments. No correlation between the degree of methylation and the Ddah2 gene expression levels was found in both types of analyzed fragments. Total Hcy but not Hcy-S-proteins correlated with iNOS promoter methylation. Analyzed variants seem to contribute to the in vivo Hcy binding properties to IMA. The contribution of the Hcy-derived methylation modifications to Ddah2 and eNOS gene expression seems to be tissue-specific and independent of the Ddah2/ADMA/eNOS pathway. Hcy-derived methylation modifications to the iNOS gene promoter contribute to a lesser extent to iNOS gene expression.

Background Endothelial progenitor cells (EPCs) are circulating angiogenic cells with endothelial features associated with risk for stroke. We aimed to delve into their functional characteristics. EPCs were isolated and cultured from Ischemic Stroke (IS) patients and predictors of their variance evaluated. Methods This is a single-center observational study evaluating 187 consecutively hospitalized patients with IS. EPCs were isolated from blood samples. The number of circulating angiogenic cells (CACs), colony-forming units (CFU-ECs) and the emergence of late outgrowths endothelial cells (LOECs) were counted. We collected clinical variables and measured the stromal cell-derived factor 1 alpha (SDF1α) serum levels. We also examined the relative telomere length and the expression of osteogenic gene markers in CACs. Results CACs counts and CFU-ECs colony numbers were positively correlated (rho = 0.41, p < 0.001, n = 187). We found significant differences according to whether thrombolytic treatment was performed in the distribution of CFU-ECs (odds ratio (OR) = 2.5; 95% confidence interval (CI) 1.01–6.35; p = 0.042) and CACs (OR = 4.45; 95% IC 1.2–15.5; p = 0.012). The main determinants of CACs variation were the number of risks factors, thrombolysis treatment, arterial hypertension, LOECs occurrence, and the vascular endothelial growth factor expression, whereas CFU-ECs variations depended on hemoglobin content and the relative reduction in the National Institutes of Health Stroke Scale (NIHSS) criteria. The main predictors of LOECs appearance were thrombolysis and length of hospital stay. Conclusions Our study supports the relevance of patient risk factors and treatments in the analysis of the functional properties of EPCs.