(Rev Méd Chile 2009; 137: 1273-82).

The influence of raised fibrinogen levels on outcome in stable outpatients with peripheral arterial disease (PAD) has not been consistently investigated. We used data from the Factores de Riesgo y ENfermedad Arterial (FRENA) registry to compare ischemic events, major bleeding, and mortality in stable outpatients with PAD, according to their baseline plasma fibrinogen levels. Of 1363 outpatients with PAD recruited in FRENA, 558 (41%) had fibrinogen levels >450 mg/100 mL. Over 18 months, 43 patients presented with acute myocardial infarction, 37 had an ischemic stroke, 51 underwent limb amputation, 19 had major bleeding, and 90 died. Compared to patients with normal levels, those with raised fibrinogen levels had an over 2-fold higher rate of ischemic stroke (rate ratio [RR]: 2.30; 95% confidence interval [CI]: 1.19-4.59), limb amputation (RR: 2.58; 95% CI: 1.46-4.67), or death (RR: 2.27; 95% CI: 1.49-3.51) and an over 3-fold higher rate of major bleeding (RR: 3.90; 95% CI: 1.45-12.1). On multivariate analysis, patients with raised fibrinogen levels had an increased risk of developing subsequent ischemic events (hazard ratio [HR]: 1.61; 95% CI: 1.11-2.32) and major bleeding (HR: 3.42; 95% CI: 1.22-9.61). Stable outpatients with PAD and raised plasma fibrinogen levels had increased rates of subsequent ischemic events and major bleeding.

Diabetes mellitus entails increased atherosclerotic burden and medial arterial calcification, but the precise mechanisms are not fully elucidated. We aimed to investigate the implication of CD36 in inflammation and calcification processes orchestrated by vascular smooth muscle cells (VSMCs) under hyperglycemic and atherogenic conditions. We examined the expression of CD36, pro-inflammatory cytokines, endoplasmic reticulum (ER) stress markers, and mineralization-regulating enzymes by RT-PCR in human VSMCs, cultured in a medium containing normal (5 mM) or high glucose (22 mM) for 72 h with or without oxidized low-density lipoprotein (oxLDL) (24 h). The uptake of 1,1′-dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate-fluorescently (DiI) labeled oxLDL was quantified by flow cytometry and fluorimetry and calcification assays were performed in VSMC cultured in osteogenic medium and stained by alizarin red. We observed induction in the expression of CD36, cytokines, calcification markers, and ER stress markers under high glucose that was exacerbated by oxLDL. These results were confirmed in carotid plaques from subjects with diabetes versus non-diabetic subjects. Accordingly, the uptake of DiI-labeled oxLDL was increased after exposure to high glucose. The silencing of CD36 reduced the induction of CD36 and the expression of calcification enzymes and mineralization of VSMC. Our results indicate that CD36 signaling is partially involved in hyperglycemia and oxLDL-induced vascular calcification in diabetes.