Introduction:
Heart failure (HF) nowadays in western countries is an immense problem largely due to its social impact as well as an economic burden. A widely accepted biomarker-based strategy to establish prognosis and predict re-hospitalization events in HF is lacking. Currently, besides natriuretic peptides and cardiac troponins, a variety of molecules are being studied. Phoenixin (PNX) is a neuropeptide mainly involved in the regulation of gonadotropin secretion. Recently, a significant cardioprotective effect of PNX was reported.

Aim:
The aim of this study was to measure PNX plasma concentration in a group of HF with reduced ejection fraction (HFrEF) patients and to compare it to levels found in HF-negative participants.

Material and methods:
A group of 74 HFrEF patients and a control group consisting of 40 participants without systolic or diastolic myocardial dysfunction were studied. Each individual underwent anthropometric measurements, laboratory testing, clinical and echocardiographic examination. To evaluate PNX plasma concentration, an immunoenzymatic assay (ELISA) was performed.

Results and discussion:
PNX plasma concentration in the HFrEF group was not statistically different than in the control group. No significant correlation between PNX level and age, sex, BMI, HF etiology, diabetes or atrial fibrillation presence was found. PNX concentration correlated positively with total and LDL cholesterol blood levels in HFrEF patients. A negative correlation was found with creatinine in HFrEF, uric acid and triglycerides levels as well as AlAT activity in the control group.

Conclusions:
There is no significant difference in PNX plasma concentration between HF and non-HF individuals. PNX role in cardiovascular disease requires further investigation.