Circulating endothelial-derived apoptotic microparticles and insulin resistance in non-diabetic patients with chronic heart failure

BACKGROUND: The objective of this study was to assess the relationship between insulin resistance and apoptotic endothelial-derived microparticles (EMPs) in patients with chronic heart failure (CHF). METHODS: The study involved 300 CHF patients (186 males) aged 48-62 years with angiographically proven coronary artery disease and/or previously defined myocardial infarction. Insulin resistance was assessed by the homeostasis model assessment for insulin resistance (HOMA-IR). EMPs phenotype was determined by flow cytofluorometry. RESULTS: Depending on HOMA-IR cut-off point (over and <2.77 mmol/L×μU/mL) all patients were divided into two cohorts with (n=171) or without (n=129) IR, respectively. Circulating EMPs were higher in CHF patients with IR than in patients without IR. Interestingly, EMPs were directly related to NYHA functional class of CHF, HOMA-IR, NT-pro-BNP, hs-CRP and BMI. There was a significant association between the level of EMPs and HbA1c, gender (r=0.318, p<0.001 for male), age and smoking. On univariate and multivariate regression analysis we found that the NYHA class of CHF,NT-pro-BNP, hs-CRP, and left ventricular ejection fraction (LVEF) appeared to be independent predictors of increased circulatory apoptotic EMPs. The addition of HOMA-IR to the standard model (NYHA class CHF) improved the relative IDI by 19.9% for increased EMPs. For category-free NRI, 10% of events and 24% of non-events were correctly reclassified by the addition of HOMA-IR to the standard model for increased circulating EMPs. CONCLUSIONS: IR may be a contributing factor increasing circulating levels of apoptotic EMPs in non-diabetic CHF patients.