SERCA2a gene therapy can improve symptomatic heart failure in δ-sarcoglycan-deficient animals

Velvet Antler Ameliorates Cardiac Function by Restoring Sarcoplasmic Reticulum Ca2+-ATPase Activity in Rats With Heart Failure After Myocardial Infarction

Objective: Velvet antler (VA; cornu cervi pantotrichum), a well-known traditional Chinese medicine, has been shown to exert cardioprotective effects. The purpose of this study was to investigate the effect of VA on heart failure (HF) caused by ischemia-reperfusion, and explore its possible mechanism from the regulation of sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase 2 alpha (SERCA2a).

Methods: A rat model of HF was established by ligating the left anterior descending coronary artery of male Sprague–Dawley rats (n = 88). One week after surgery, VA (200, 400, or 800 mg/[kg day⁻¹]) or enalapril (1 mg/[kg day⁻¹]) was administered daily for the next 4 weeks. Heart function was detected by echocardiography and histopathological analysis. The serum BNP level was measured by ELISA, and the expression of SERCA2a, PLB, PLB-Ser¹⁶, and PKA was determined by western blotting. SERCA2a and PLB mRNA levels were determined by real-time quantitative PCR.

Results: Compared with the sham group, cardiac function in the HF group, including the serum BNP level, heart mass index, myocardial collagen deposition, and left ventricular ejection fraction, was markedly reduced; however, these changes could be reversed by VA treatment. In addition, VA (200 mg/[kg·d⁻¹]) inhibited the decrease of SERCA2a and PLB mRNA levels and SERCA2a, PLB, PLB-Ser¹⁶, and PKA protein expression and restored the activity of SERCA2a and PKA. Enalapril affected only PLB protein expression.

Conclusion: VA can improve myocardial fibrosis and ventricular remodeling in rats, thereby helping to restore cardiac function. The underlying mechanism may be related to the upregulation of the expression and activation of PKA and PLB and the restoration of the expression and activity of SERCA2a.

Novel Therapies for Heart Failure - Where Do They Stand?

Despite advances in therapy, patients with heart failure (HF) continue to experience unacceptably high rates of hospitalization and death, as well as poor quality of life. As a consequence, there is an urgent need for new treatments that can improve the clinical course of the growing worldwide population of HF patients. Serelaxin and ularatide, both based on naturally occurring peptides, have potent vasodilatory as well as other effects on the heart and kidneys. For both agents, phase 3 studies that are designed to determine whether they improve outcomes in patients with acute HF have completed enrollment. TRV027, a biased ligand for the type 1 angiotensin receptor with effects that extend beyond traditional angiotensin-receptor blockers is also being studied in the acute HF population. Omecamtiv mecarbil, an inotropic agent that improves myocardial contractility by a novel mechanism, and vericiguat, a drug that stimulates soluble guanylate cyclase, are both being developed to treat patients with chronic HF. Finally, despite the negative results of the CUPID study, gene transfer therapy continues to be explored as a means of improving the function of the failing heart. The basis for the use of these drugs and their current status in clinical trials are discussed. (Circ J 2016; 80: 1882-1891).

Gene therapy for heart failure

Heart failure is a major public health problem throughout the world and it is likely that its prevalence will continue to grow over the next several decades. Despite advances in the treatment of heart failure, morbidity and mortality remain unacceptably high. Gene transfer therapy provides a novel strategy for targeting abnormalities in cardiac cells that adversely affect cardiac function. New vectors for gene delivery, mainly adeno-associated viruses (AAVs) that are preferentially taken up by cardiomyocytes, can result in sustained transgene expression. The cardiac isoform of sarco(endo)plasmic reticulum Ca(2+)ATPase (SERCA2a) plays a major role in regulating calcium levels in cardiomyocytes. Abnormal calcium handling by the failing heart caused by a reduction in SERCA2a activity adversely affects both systolic and diastolic function. The Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID) study was a Phase 2a double-blind, randomized, placebo-controlled, dose-finding study that was performed in patients with advanced heart failure due to systolic dysfunction. Eligible patients received AAV/SERCA2a or placebo by direct antegrade infusion into the coronary circulation. At the end of 12 months, patients receiving high-dose therapy (i.e. 1×10(13) DNase Resistant Particles) had evidence of favorable changes in several clinically relevant domains compared to patients treated with placebo. There were no safety concerns at any dose of AAV/SERCA2a. Patients treated with AAV/SERCA2a exhibited a striking reduction in cardiovascular events that persisted through 36 months of follow-up compared to patients who received placebo. Transgene expression was detected in the myocardium of patients receiving AAV/SERCA2a gene therapy as long as 31 months after delivery. A second Phase 2b study, CUPID 2, designed to confirm this favorable effect on heart failure events, is currently underway with the results expected to be presented later in 2015. Additional studies using other vectors and targets are in planning or underway making gene transfer therapy one of the most exciting new approaches under development for treating heart failure.

Duchenne muscular dystrophy gene therapy in the canine model

Duchenne muscular dystrophy (DMD) is an X-linked lethal muscle disease caused by dystrophin deficiency. Gene therapy has significantly improved the outcome of dystrophin-deficient mice. Yet, clinical translation has not resulted in the expected benefits in human patients. This translational gap is largely because of the insufficient modeling of DMD in mice. Specifically, mice lacking dystrophin show minimum dystrophic symptoms, and they do not respond to the gene therapy vector in the same way as human patients do. Further, the size of a mouse is hundredfolds smaller than a boy, making it impossible to scale-up gene therapy in a mouse model. None of these limitations exist in the canine DMD (cDMD) model. For this reason, cDMD dogs have been considered a highly valuable platform to test experimental DMD gene therapy. Over the last three decades, a variety of gene therapy approaches have been evaluated in cDMD dogs using a number of nonviral and viral vectors. These studies have provided critical insight for the development of an effective gene therapy protocol in human patients. This review discusses the history, current status, and future directions of the DMD gene therapy in the canine model.