Chronic heart failure with reduced and mildly reduced left ventricle ejection fraction: relationship between mitochondrial respiratory dysfunction of peripheral blood mononuclear cells and iron deficiency

Objectives  To compare respiratory parameters of peripheral blood mononuclear cell mitochondria and iron metabolism indicators in patients with different NYHA functional classes of ischemic heart failure (HF).

Methods  This single center, prospective, non-blinded study enrolled 20 patients with diagnosed chronic HF of ischemic genesis with reduced and mildly reduced left ventricle ejection fraction. The maximum oxygen consumption at the peak of the exercise test (VO₂ peak), iron metabolism parameters and respiratory activity of peripheral blood mononuclear cell mitochondria were assessed.

Results  Among the patients, a half of individuals were diagnosed with iron deficiency. Subgroups of patients with different HF severity did not significant differ in VO₂ peak (P = 0.209), serum iron (P = 0.468) and ferritin (P = 0.235) levels. But there was a trend in increasing in these parameters with increasing NYHA HF functional class. Respiratory control coefficient (RC) in NAD-dependent and FAD-dependent mitochondrial oxidation were lower in patients with NYHA HF III functional class compared to individuals with NYHA HF I functional class (P = 0.028 and P = 0.040, respectively). Serum iron (P = 0.026), ferritin (P = 0.045) levels, transferrin saturation (P = 0.006) were negatively correlated with RC in NAD-dependent mitochondrial oxidation.

Conclusions  In aggravation of ischemic HF NYHA FC, there is a decrease in RC of PBMC mitochondria during the oxidation of NAD-dependent and FAD-dependent substrates. In the whole sample, patients with laboratory-confirmed iron deficiency accounted a half of the total number. Iron metabolism parameters had a paradoxical inverse relationship with the level of RC in PBMC mitochondria of patients with HF.