Leukocyte labile iron pool in patients with systolic heart failure

Data regarding sources of oxidative stress in the failing myocardium are sparse. Leukocytes actively participate in the oxidative damage observed in human heart failure (HF). The intracellular labile iron pool (LIP) represents a source of toxic reactive oxygen species.

We studied patients with chronic systolic HF who had a left ventricular ejection fraction (LVEF) 45%. We examined the LIP status in different populations of leukocytes in HF patients and we investigated its association with clinical and laboratory parameters, including conventional inflammatory markers.

Sixty patients were finally included in the analysis (mean age: 67 ± 11 years, 54 men, 42 with ischemic cardiomyopathy). The multivariate logistic regression analysis showed that only LIP in granulocytes (OR: 0.73; 95% CI: 0.55-0.98; p=0.039) and right ventricular systolic pressure (RVSP) (OR: 0.95; 95% CI: 0.92-0.99; p=0.027) were independently associated with severe LV systolic dysfunction (LVEF30%). The correlation analysis revealed that LVEF was inversely associated with LIP in granulocytes (Spearman's rho: -0.39, p=0.002), LIP in monocytes (Spearman's rho: -0.35, p=0.007), and RVSP (Spearman's rho: -0.43, p=0.003). No significant correlation between LVEF and inflammatory indexes was noted.

LIP in granulocytes is independently associated with the severity of LV dysfunction in patients with systolic HF. Intracellular redox active iron may represent a source of leukocyte reactive oxygen species in this setting.