SAT670 Is Myostatin A Biomarker Of Skeletal Muscle Mass?

Disclosure: L. Orioli: None. S. Samaras: None. P. Lause: None. M. de Barsy: None. J.M. Thissen: None. A. Loumaye: None. Rationale: Our study aims to determine whether myostatin is a biomarker of muscle mass in cancer cachexia and obesity. Methods: The ACTICA study included cancer patients with and without cachexia. The MYDIASECRET study included obese patients evaluated before and 3 months after bariatric surgery. Body composition was assessed using bioelectrical impedance analysis (BIA101 device, Akern). Skeletal muscle mass (SMM) and appendicular SMM (ASMM) were calculated from Janssen’s and Sergi’s equations, respectively. Results were expressed as indexes (kg/m²). Myostatin plasma concentrations were determined using ELISA. Spearman’s coefficient was used to correlate muscle mass indexes and myostatin. Results: The ACTICA study included 143 patients of whom 70 with cachexia. SMM index (SMMI) and ASMM index (ASMMI) were lower in patients with cachexia compared to those without cachexia (SMMI: 8.0 kg/m² [6.7-9.5] vs 9.0 kg/m² [7.8-10.1], p=0.004; ASMMI: 6.2 kg/m² [5.5-7.1] vs 7.2 kg/m² [6.4-7.8], p<0.001). Myostatin was also lower in patients with cachexia (1434 pg/mL [999-2118] vs 2149 pg/mL [1551-2984], p<0.001). Myostatin was positively correlated with SMMI and ASMMI (SMMI: R=0.500, p<0.001; ASMMI: R=0.479, p<0.001). The MYDIASECRET study included 62 patients. SMMI and ASMMI were decreased after surgery (SMMI: -0.8 kg/m², p<0.001; ASMMI: -1.1 kg/m², p<0.001). Myostatin was also decreased after surgery (1773 pg/mL [1440-2309] vs 2582 pg/mL [1708-3522], p<0.001). Myostatin was positively correlated with SMMI before (R=0.388, p=0.002) and after surgery (R=0.435, p<0.001). Change in myostatin after surgery was also positively correlated with change in SSMI (R=0.287, p=0.023). Conclusion: Myostatin is positively correlated with muscle mass indexes in different conditions, suggesting its potential role as a biomarker of muscle mass. Presentation: Saturday, June 17, 2023