Na+/K+-ATPase DR region antibody ameliorated cardiac hypertrophy and fibrosis in rats with 5/6 nephrectomy.

The enzyme Na+/K+-ATPase (NKA) is important in the heart. Reductions in NKA activity and expression have often been observed in chronic kidney disease (CKD)-related heart injury. Previously, our group found that an antibody targeting the NKA1α1 subunit's DR extracellular region (897DVEDSYGQQWTYEQR911) stimulated NKA activities and produced cardioprotective effects against ischemic injury and isoproterenol-induced cardiac remodeling. In here, we assessed whether DRm217, a specific DR antibody, exhibits cardioprotective effects in chronic renal failure models. In 5/6 nephrectomy (5/6 Nx) surgery to mimic CKD in Sprague Dawley rat, we observed that NKA activity and expression were depressed in the hearts of 5/6 Nx rats. DRm217, an NKA DR region antibody, alleviated heart hypertrophy and cardiac fibrosis under 5/6 Nx conditions. Further studies revealed that DRm217 inhibited Src activation and reduced reactive oxygen species (ROS) levels in hearts under 5/6 Nx conditions. Our findings imply that NKA could be a treatment target in CKD-related cardiac diseases. Prevention of CKD-induced myocardial injury by DRm217 provides an appealing therapeutic alternative.