Effects of stress hyperglycemia on acute myocardial infarction: role of inflammatory immune process in functional cardiac outcome

Abstract

Objective: Stress hyperglycemia has been associated with increased mortality in patients with myocardial infarction (MI). We examined the association between plasma glucose levels, circulating inflammatory markers, T-cell activation, and functional cardiac outcome in patients with first MI.

Research design and methods: Echocardiographic parameters, circulating levels of interleukin-18 (IL-18), C-reactive protein (CPR), and the percent of CD16-CD56, CD4/CD8, CD152, and HLA-DR expression were investigated in 108 patients with acute MI on admission to the emergency ward.

Results: Our review found that 31 new hyperglycemic patients (glycemia >or=7 mmol/l) had higher infarct segment length (P < 0.05) and myocardial performance index (P < 0.02) and reduced transmitral Doppler flow (P < 0.05), pulmonary flow analysis (P < 0.02), and ejection fraction (P < 0.05) compared with 36 hyperglycemic diabetic patients and 41 normoglycemic patients. Plasma IL-18 and CRP were higher in the hyperglycemic than in the normoglycemic patients (P < 0.005), with the highest values in patients with new hyperglycemia (P < 0.05). Hyperglycemic patients had a higher percent of CD16+/CD56+ cells and CD4/CD8 ratio (P < 0.01), whereas they had lower CD152 expression (which has a negative regulatory function in T-cell activation) compared with normoglycemic patients (P < 0.001).

Conclusions: During MI, hyperglycemia is associated with increased levels of inflammatory markers, enhanced expression of cytotoxic T-cells, and reduced expression of T-cells, which are implicated in limiting the immune process. An increased inflammatory immune process seems a likely mechanism linking acute hyperglycemia to poor cardiac outcome in MI patients.