TCF7L2 polymorphism is associated with low nitric oxide release, endothelial dysfunction and enhanced inflammatory response after myocardial infarction.

BACKGOUND: The favorable effects of insulin during myocardial infarction (MI) remain unclear due to the divergence between mechanistic studies and clinical trials of exogenous insulin administration. The rs7903146 polymorphism of the transcription factor 7-like 2 (TCF7L2) gene is associated with attenuated insulin secretion. METHODS: In non-diabetic patients with ST-elevation MI (STEMI), using such a model of genetically determined down-regulation of endogenous insulin secretion we investigated the change in plasma insulin, C-peptide, interleukin-2 (IL-2), C-reactive protein (CRP), and nitric oxide (NOx) levels between admission (D1) and the fifth day after MI (D5). Coronary angiography and flow-mediated dilation (FMD) were performed at admission and 30 days after MI, respectively. Homeostasis Model Assessment estimated insulin secretion (HOMA2%ß) and insulin sensitivity (HOMA2%S). RESULTS: Although glycemia did not differ between genotypes, carriers of the T-allele had lower HOMA2%ß and higher HOMA2%S at both D1 and D5. As compared with non-carriers, T-allele carriers had higher plasma IL-2 and CRP at D5, higher intracoronary thrombus grade, lower FMD and NOx change between D1 and D5 and higher 30-day mortality. CONCLUSION: In non-diabetic STEMI patients, the rs7903146 TCF7L2 gene polymorphism is associated with lower insulin secretion, worse endothelial function, higher coronary thrombotic burden, and higher short-term mortality. GENERAL SIGNIFICANCE: During the acute phase of MI, a lower capacity of insulin secretion may influence clinical outcome.

Glycosylated hemoglobin is associated with decreased endothelial function, high inflammatory response, and adverse clinical outcome in non-diabetic STEMI patients.

OBJECTIVE: Chronic dysglycemia was recently identified as a predictor for adverse outcomes in patients with ST-elevation myocardial infarction (STEMI) treated by percutaneous coronary intervention. Data for non-diabetic patients who underwent thrombolysis is scarce. In this context, we aimed to study the effect of HbA1c on cardiovascular outcome after STEMI. METHODS: A prospective cohort of 326 non-diabetic STEMI individuals was used for the analyses. We measured plasma glucose, hemoglobin A1c [HbA1c], lipid profile, C-reactive protein (CRP), and nitrate/nitrite (NOx) upon admission and five days after STEMI (D5). Flow-mediated dilation (FMD) was performed 30 days after STEMI. During clinical follow-up, we assessed patients for incident diabetes (progression to HbA1c ≥ 6.5%) and major adverse cardiac events (MACE), defined as a composite of fatal and non-fatal MI, sudden cardiac death, and angina requiring hospitalization. RESULTS: Using ROC-curve analysis, a 5.8% HbA1c best predicted MACE with a sensitivity of 75% and specificity of 53% (AUC 0.673, p = 0.001). Patients were categorized as high HbA1c if ≥ 5.8% and low HbA1c if <5.8%. Compared with patients with low HbA1c, those with high HbA1c presented with 20% higher CRP-D5 (p = 0.009) and 19% higher ΔCRP (p = 0.01), a 32% decrease in ΔNOx (p < 0.001), and 33% lower FMD (p < 0.001). After a median follow-up of 1.9 (1.1-2.8) years, patients with high HbA1c had more incident diabetes (HR 2.3 95% CI 1.01-5.2; p = 0.048) and MACE (HR 3.32 95% CI 1.09-10.03; p = 0.03). CONCLUSION: Non-diabetic STEMI patients with high HbA1c present with decreased endothelial function and increased inflammatory response and long-term risk of MACE.