Xifu Liu

A Phase II, Randomized, Double-Blind, Multicenter, Based on Standard Therapy, Placebo-Controlled Study of the Efficacy and Safety of Recombinant Human Neuregulin-1 in Patients With Chronic Heart Failure

OBJECTIVES The purpose of this study was to assess the safety and efficacy of recombinant human neuregulin-1 (rhNRG-1) in chronic heart failure (CHF) patients. BACKGROUND Neuregulin-1 plays important roles in maintaining cardiomyocyte structure and cardiac pumping functionality and physiology. Previously, rhNRG-1 was proven to be effective in treating heart failure in animals by reducing end-diastolic volume (EDV) and end-systolic volume (ESV) and increasing left ventricular ejection fraction (LVEF%). METHODS A total of 44 CHF patients designated as New York Heart Association functional class II or III were enrolled in a double-blind, randomized manner and treated with a placebo or rhNRG-1 (0.3, 0.6, or 1.2 microg/kg/day) for 10 days, in addition to standard therapies. The follow-up period was 90 days; left ventricular function and structure measured by magnetic resonance imaging were the primary end points. RESULTS Although not statistically different from placebo, the LVEF% was significantly increased by 27.11 +/- 31.12% (p = 0.009) at day 30 after rhNRG-1 treatment in the 0.6-microg/kg group, whereas it was only increased 5.83 +/- 25.75% in the placebo group (p = 0.49). In addition, there were decreases in ESV (-11.58 +/- 12.74%, p = 0.002) and EDV (-5.64 +/- 10.03%, p = 0.05) in the 0.6-microg/kg/day group at day 30; more importantly, both ESV and EDV levels continued to decrease at day 90 (-20.79 +/- 17.03% and -14.03 +/- 13.17%, respectively), accompanied by a sustained increase in LVEF%. This suggests that short-term treatment with rhNRG-1 results in a long-term reversal of remodeling. The effective dose was proven to be tolerable and safe for CHF patients. CONCLUSIONS rhNRG-1 improved the cardiac function of CHF patients by increasing the LVEF% and showed the capability of antiremodeling by decreasing ESV and EDV compared with pre-treatment. (A Randomized, Double-Blind, Multi-Center, Placebo Parallel controlled, Standard Therapy Based Phase II Clinical Trial to Evaluate the Efficacy and Safety of Recombinant Human Neuregulin-1 for Injection in Patients with Chronic Heart Failure; ChiCTR-TRC-00000414).

Parenteral administration of recombinant human neuregulin‐1 to patients with stable chronic heart failure produces favourable acute and chronic haemodynamic responses

Neuregulin‐1 (NRG‐1) plays a critical role in the adaptation of the heart to injury, inhibiting apoptosis and inducing cardiomyocyte proliferation. We have shown previously that rhNRG‐1 improves cardiac function and survival in animal models of cardiomyopathy. Here we report the first human study aimed at exploring the acute and chronic haemodynamic responses to recombinant human NRG‐1 (beta2a isoform; rhNRG‐1) in patients with stable chronic heart failure (CHF).

Neuregulin 1 Sustains the Gene Regulatory Network in Both Trabecular and Nontrabecular Myocardium

Rationale: The cardiac gene regulatory network (GRN) is controlled by transcription factors and signaling inputs, but network logic in development and it unraveling in disease is poorly understood. In development, the membrane-tethered signaling ligand Neuregulin (Nrg)1, expressed in endocardium, is essential for ventricular morphogenesis. In adults, Nrg1 protects against heart failure and can induce cardiomyocytes to divide. Objective: To understand the role of Nrg1 in heart development through analysis of null and hypomorphic Nrg1 mutant mice. Methods and Results: Chamber domains were correctly specified in Nrg1 mutants, although chamber-restricted genes Hand1 and Cited1 failed to be activated. The chamber GRN subsequently decayed with individual genes exhibiting decay patterns unrelated to known patterning boundaries. Both trabecular and nontrabecular myocardium were affected. Network demise was spatiotemporally dynamic, the most sensitive region being the central part of the left ventricle, in which the GRN underwent complete collapse. Other regions were partially affected with graded sensitivity. In vitro, Nrg1 promoted phospho-Erk1/2–dependent transcription factor expression, cardiomyocyte maturation and cell cycle inhibition. We monitored cardiac pErk1/2 in embryos and found that expression was Nrg1-dependent and levels correlated with cardiac GRN sensitivity in mutants. Conclusions: The chamber GRN is fundamentally labile and dependent on signaling from extracardiac sources. Nrg1–ErbB1/4–Erk1/2 signaling critically sustains elements of the GRN in trabecular and nontrabecular myocardium, challenging our understanding of Nrg1 function. Transcriptional decay patterns induced by reduced Nrg1 suggest a novel mechanism for cardiac transcriptional regulation and dysfunction in disease, potentially linking biomechanical feedback to molecular pathways for growth and differentiation.

Cardiac functional improvement in rats with myocardial infarction by up-regulating cardiac myosin light chain kinase with neuregulin.

AIMS Recombinant human neuregulin-1 (rhNRG-1) improves cardiac function in experimental heart failure models, but the underlying mechanism remains largely unknown. In this study, we evaluated whether rhNRG-1 could improve cardiac function via the cardiac myosin light chain kinase/myosin light chain 2 ventricular (cMLCK/MLC-2v) pathway in rats with myocardial infarction (MI). METHODS AND RESULTS Rats with MI were intravenously infused with rhNRG-1 (5 µg/kg/h) for 7 days through osmotic pumps. The mechanism of action of rhNRG-1 was investigated by assaying the non-infarcted myocardium with gene chips. The cMLCK expression, phosphorylated MLC-2v and cardiac function were significantly up-regulated, as assessed by real-time PCR, Western blot and echocardiography, in those animals treated with rhNRG-1. Moreover, the restoration of rhNRG-1-induced sarcomeric organization in serum-free cultured neonatal rat cardiomyocytes with rhNRG-1 was inhibited by cMLCK RNA interference or ML-7, an inhibitor of MLCKs. Adenovirus containing the rat cMLCK coding region was injected into non-infarcted myocardium, and cardiac function was monitored using echocardiography and a haemodynamic machine. The dP/dt and fractional shortening decreasing significantly after MI, and improved by 15.7 and 32.1%, respectively, following local cMLCK application (all P < 0.05). CONCLUSION Our results suggest that cMLCK is a downstream effector of rhNRG-1 involved in rhNRG-1-induced cardiac function improvement, and that myocardial cMLCK up-regulation can improve cardiac function in rats with MI.

A recombinant human neuregulin-1 peptide improves preservation of the rodent heart after prolonged hypothermic storage.

Background. Donor hearts are subjected to ischemia-reperfusion injury during transplantation. Recombinant human neuregulin (rhNRG)-1 peptide attenuates myocardial injury in various animal models of cardiomyopathy. Supplementing the organ-storage solution, Celsior (C), with glyceryl trinitrate (GTN) and cariporide improves cardiac preservation after hypothermic storage. We hypothesized that the addition of rhNRG-1 to C would improve cardiac preservation after hypothermic storage and provide incremental benefit in combination with GTN and cariporide. Methods. An isolated working rat heart model was used. To assess the effect of rhNRG-1, hearts were stored for 6 hr at 4°C in C±rhNRG-1 (14 nM). To assess the effect of using a combination of prosurvival kinase activators on cardiac preservation, the ischemic storage time was extended to 10 hr and hearts stored in C±rhNRG-1 (14 nM)±GTN (0.1 mg/mL)±Cariporide (10 &mgr;M). Hearts were subsequently reperfused, cardiac function remeasured, and tissue collected for protein analysis and immunohistochemistry. Optimal timing of rhNRG-1 administration was also assessed. Results. rhNRG-1 supplemented C improved functional recovery after 6 hr of storage (cardiac output recovery [mean±SEM]: control 1.4%±0.6%; rhNRG-1+C 21.1%±7.9%; P<0.05). After 10-hr storage, no improvement in functional recovery was observed with rhNRG-1, GTN, or cariporide alone; however, GTN combined with cariporide did improve recovery (P<0.01), which was further enhanced by the addition of rhNRG-1 (P<0.01). Functional improvements were accompanied by increased phosphorylation of Akt, ERK1/2, STAT3, and GSK-3&bgr; and reduced cleaved caspase-3 (P<0.01). Conclusions. rhNRG-1 given together with other activators of prosurvival pathways improves preservation of the rat heart and shows promise for increasing the cold-ischemic life of donor hearts in transplantation.

Neuregulin-1/ErbB Signaling and Chronic Heart Failure

Neuregulin-1 (NRG-1), a cardioactive growth factor released from endothelial cells, is indispensable for cardiac development, structural maintenance, and functional integrity of the heart. In recent years, a growing number of studies have focused on NRG-1 and members of the ErbB family that serve as receptors for NRG-1 in order to better understand the role of this signaling pathway in physiology and pathophysiology of the heart. An essential role for NRG-1 and ErbB in heart development and functionality has been suggested by studies in conditional NRG-1/ErbB-deficient mice and by the cardiac-related side effects of anti-ErbB2 antibody therapies used for treatment of breast cancer. In vitro and in vivo studies using recombinant human neuregulin-1 (rhNRG-1), which contains the epidermal growth factor (EGF)-like domain (necessary for ErbB2/ErbB4 activation), have further supported the hypothesis that NRG-1 plays an important role in heart function. Consistent with other studies, expression of rhNRG-1 not only restored normal cardiomyocytic structure altered by nutritional deficiency in cell cultures, but also improved the pumping function of the heart in several animal models of chronic heart failure (CHF). As a result of these findings, proteins involved in the NRG-1/ErbB-signaling pathway have been explored as potential drug targets for treatment of heart failure. Clinical trials to evaluate the safety and efficacy of rhNRG-1 have been conducted in both China and Australia. As predicted, rhNRG-1 treatment improved both cardiac function and reversed remodeling of the heart. Therefore, rhNRG-1 may represent a new drug for treatment of CHF with a novel therapeutic mechanism.