PACAP-38 and PAC1 Receptor Alterations in Plasma and Cardiac Tissue Samples of Heart Failure Patients

Pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) is a multifunctional neuropeptide, which may play a role in cardioprotection. However, little is known about the presence of PACAP-38 in heart failure (HF) patients. The aim of our study was to measure the alterations of PACAP-38 like immunoreactivity (LI) in acute (n = 13) and chronic HF (n = 33) and to examine potential correlations between PACAP-38 and HF predictors (cytokines, NT-proBNP). Tissue PACAP-38 LI and PAC1 receptor levels were also investigated in heart tissue samples of patients with HF. Significantly higher plasma PACAP-38 LI was detected in patients with acute HF, while in chronic HF patients, a lower level of immunoreactivity was observed compared to healthy controls (n = 13). Strong negative correlation was identified between plasma PACAP-38 and NT-proBNP levels in chronic HF, as opposed to the positive connection seen in the acute HF group. Plasma IL-1 beta, IL-2 and IL-4 levels were significantly lower in chronic HF, and IL-10 was significantly higher in patients with acute HF. PACAP-38 levels of myocardial tissues were lower in all end-stage HF patients and lower PAC1 receptor levels were detected in the primary dilated cardiomyopathy group compared to the controls. We conclude that PACAP-38 and PAC1 expression correlates with some biomarkers of acute and chronic HF; therefore, further studies are necessary to explore whether PACAP could be a suitable prognostic biomarker in HF patients.

Automated summary

This study aimed to investigate the presence of PACAP-38 in heart failure (HF) patients and its correlation with HF predictors. The results showed that plasma PACAP-38 immunoreactivity was higher in acute HF patients, while lower in chronic HF patients. In addition, a positive correlation between plasma PACAP-38 and NT-proBNP levels was observed in acute HF, but a negative correlation in chronic HF. The levels of cytokines IL-1 beta, IL-2, IL-4 were lower in chronic HF, and IL-10 was higher in acute HF. PACAP-38 levels in myocardial tissues were lower in all end-stage HF patients. The study suggests that PACAP-38 may be a potential prognostic biomarker in HF.