Decreased free sphingoid base concentration in the plasma of patients with chronic systolic heart failure
Purpose: In recent years, the role of sphingolipids in pathophysiology of the heart attracted much attention. Ceramide was found to be involved in the pathogenesis of cardiac dysfunction in animal models of ischemia/reperfusion injury, type 2 diabetes and lipotoxic cardiomyopathy. On the other hand, sphingosine-1-phosphate (S1P), has been shown to possess potent cardioprotective properties. The aim of the present study was to examine plasma concentrations of major sphingolipids in patients with chronic heart failure (HF). Material and Methods: The subjects were divided into two major groups: 1) with chronic systolic HF (n=47), and 2) healthy age-matched controls (n=15). Patients in the former group were further divided according to the underlying cause of HF (ischemic heart disease or idiopathic dilated cardiomyopathy, n=29 and 18, respectively). Results: Plasma concentrations of S1P, sphinganine-1-phosphate and ceramide observed in both groups of HF patients were very close to these noted in the healthy controls, and no statistically significant differences were found. However, the level of free sphingosine and sphinganine in the plasma of patients with HF decreased by 25 and 27%, respectively, as compared to the control subjects. This effect was independent from the underlying cause of HF as the mean concentrations of these sphingoid bases in patients with ischemic and idiopathic HF were virtually the same. Conclusions: We conclude that chronic heart failure is associated with decreased concentration of free sphingoid bases in the plasma. However, despite lower availability of substrates required for synthesis of cardioprotective sphingoid base-1 phosphates, their plasma level remains stable.