Lipoprotein Subfractions in Patients with Sarcopenia and Their Relevance to Skeletal Muscle Mass and Function.

Objective: Loss of skeletal muscle mass is a characteristic of aging. Growing evidence suggests the role of fatty acids and their derived lipid intermediates in the regulation of skeletal muscle and function. However, the exact association between lipoprotein subfractions and sarcopenia in elderly individuals remains unclear. In this study, we aimed to investigate the levels of lipoprotein subfractions in sarcopenia patients and their relationship with skeletal muscle mass and function. yMethods: A total of 84 elderly Chinese subjects aged >= 65 years who did not have diseases that obviously affected lipid metabolism were included. Concentrations of lipoprotein subfractions, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), HDL2, HDL3, low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), VLDL3, LDL-particle (LDL-P), lipoprotein (a) and remnant-like particle cholesterol (RLP-C), were determined by vertical auto profile. Triglyceride (TG) was measured by an enzymatic colorimetric assay. The skeletal muscle index (SMI) was assessed by bioelectrical impedance analysis. Handgrip strength was measured using a hand-held dynamometer. Results: The levels of TC, TG, LDL-C, LDL-P, IDL, VLDL, VLDL3, RLP-C and C-reactive protein were significantly higher in sarcopenia patients than in controls (p < 0.05). Pearson Product-Moment Correlation Coefficient analysis showed that the TC, TG, LDL-C, IDL, VLDL, VLDL3, and RLP-C levels were negatively associated with the SMI; The TG, IDL, VLDL, VLDL3, and RLP-C were negatively correlated with handgrip strength. In multivariate stepwise regression analysis, the VLDL and RLP-C levels were significantly correlated with the SMI. The sensitivity and specificity of the combined measurement of VLDL and RLP-C in predicting sarcopenia were 69.8% and 92.5% (AUC: 0.831; 95% CI:(0.739, 0.924); p < 0.05). Conclusion: The occurrence of sarcopenia is associated with disorders of lipid metabolism, particularly VLDL and RLP-C.