Disrupted Serotonergic and Sympathoadrenal Systems in Patients with Chronic Heart Failure May Serve as New Therapeutic Targets and Novel Biomarkers to Assess Severity, Progression and Response to Treatment

Background: It is well established that the serotonergic system (SS) plays important roles in the pathogenesis of cardiovascular diseases. However, the impact of serotonin and its inter-relation with the sympathoadrenal system (SAS) in chronic heart failure (CHF) is poorly understood. Methods: Utilizing high-performance liquid chromatography with electrochemical detection, we determined blood plasma levels of serotonin (5-hydroxy-triptamine, [5-HT]p), 5- hydroxy-indole-acetic acid ([5-HIAA]p), epinephrine ([E]p), norepinephrine ([NE]p), 3,4-dihydroxy-L-phenyl-alanine ([DOPA]p), dopamine ([DA]p) and the platelet concentration of serotonin ([5-HT]pt) in CHF patients with different morphofunctional alterations of myocardium. The morphofunctional alterations included diastolic dysfunction (DD), diastolic dysfunction with left ventricular hypertrophy (DD&LVH), and diastolic and systolic dysfunction (D&SD). Results: All CHF groups showed significant rises of [5-HT]p and [5-HT]pt. DD&LVH and D&SD individuals also had increased [5-HIAA]p. Levels of SAS blood biomarkers were also significantly changed. The correlation between SS and SAS was increased in CHF and corresponded with disease severity. Conclusions: These results clearly demonstrate that in CHF patients significant changes in SS and SAS occur, which are thought to relate to the morphofunctional alterations of myocardium. The observed changes in the levels of these biomarkers may serve as potential surrogates to monitor severity of disease, to evaluate response to drug treatment, and as a rational basis for new therapeutic approaches.