Human epididymis protein 4 indicates progression of cardiac fibrosis in Heart Failure with preserved Ejection Fraction

Abstract

Abstract Background Cardiac fibrosis is one of the main causes of diastolic dysfunction in heart failure with preserved ejection fraction (HFpEF). Human epididymis protein 4 (HE4) is a novel pro-fibrotic protein expressed especially in activated fibroblast, so-call myofibroblast [1]. Although our previous study showed that HE4 functioned as a secretory factor promoting cardiac fibrosis in dilated cardiomyopathy [2], little is known about the role of HE4 in HFpEF. Purpose The aim of this study is to evaluate the pathophysiological role of HE4 in HFpEF and the association between serum HE4 levels and clinical course of HFpEF. Methods In basic research, we administered high-fat diet and NOS inhibitor (L-NAME) to mice for 5 weeks to induce HFpEF. We analyzed echocardiographic findings and mRNA expressions of fibrosis-related genes including HE4 by real time PCR. In clinical research, we measured serum HE4 levels of 79 patients with HFpEF and divided these patients into low and high HE4 group using median values of HE4 (102.0 pmol/L). Then, we evaluated their mortality and cardiovascular events retrospectively. Results In vivo, the administration of high fat diet and L-NAME induced significant increase in left ventricular mass on echocardiography compared with control group (p=0.006). The mRNA expressions of aSMA and collagen3a1 in heart tissue was upregulated in HFpEF model mice (p=0.008 and p=0.003, respectively). Furthermore, the mRNA expression of HE4 was also upregulated in HFpEF model mice (n=6) than in control mice (n=5), although these differences did not reach statistical significance (p=0.238). In vitro, recombinant HE4 upregulated mRNA expression of pro-fibrotic genes, such as periostin (p=0.001), collagen3a1 (p=0.037), aSMA (p=0.095), and PAI-1 (p=0.17), indicating HE4 facilitate the activation of fibroblast and cardiac fibrosis although some did not reach statistical significance. In clinical research, Kaplan-Meier curve revealed that the rate of all cause death and rehospitalization for worsening heart failure were significantly higher in the high than the low HE4 group, suggesting HE4 can predicts prognosis in patients with HFpEF. Conclusion HE4 induces the activation of cardiac fibroblasts and is upregulated in the heart of HFpEF model mice. Furthermore, it is a useful biomarker for predicting cardiovascular events in patients with HFpEF. Funding Acknowledgement Type of funding sources: None.