Protein translation and degradation signaling in skeletal muscle following total hip arthroplasty with or without an essential amino acid supplement

Abstract

Total hip arthroplasty (THA) and other major orthopedic surgical procedures lead to severe atrophy of skeletal muscles around the affected area. This atrophy can persist two years or longer. As these surgeries are often performed on older patients already suffering from atrophy, further loss of muscle mass can seriously impact quality of life. Attenuation of muscle loss post‐THA is critical for rapid recovery of mobility and function. The purpose of this study was to determine the effects of an essential amino acid supplement (EAA) on signaling pathways regulating muscle mass in THA patients. THA patients were given normal standard of care or an AA (Travasol 10%) during surgery and EAA capsules thrice daily post‐surgery. Muscle samples obtained perioperatively and at discharge from acute care were analyzed via Western blot for markers of protein translation and degradation and compared to matched controls (CON). Patients who did not receive the EAA supplement had significantly lower phosphorylated 4EBP1 perioperatively. Calpastatin levels were significantly lower at discharge in both groups relative to perioperative and CON. Interestingly, atrogin‐1 levels were lower than CON in both THA groups at both time points. No differences were found in other pathways. Based off these markers, the EAA supplement might act through 4EBP1 to modulate protein synthesis, but does not likely have any effect on degradation.