Circulating C-Terminal Agrin Fragment: A Potential Marker for Sarcopenia Among Type 2 Diabetes

Undetected onset of sarcopenia among individuals with chronic diseases especially Type 2 Diabetes Mellitus (T2D) makes it important to be evaluated. The feasibility of diagnosing sarcopenia in a clinical setup might be a difficult task. Circulating markers including C-terminal agrin fragment (CAF) are emerging as an alternative. Hence, the objectives of the study were to compare circulating CAF levels between T2D, prediabetes (PD) and healthy controls and to study its association with sarcopenic index, muscle mass, strength and quality.

Ninety-nine participants (n = 42, T2D; n = 33, PD; n = 24, healthy controls) aged 18 to 60 yrs were recruited. HOMA (homeostatic model assessment) indices were derived using plasma glucose and insulin. All participants underwent lipid profiling, muscle strength including quality (isokinetic dynamometer), body composition (Dual energy X-ray Absorptiometry (DXA)) and sarcopenic index (appendicular skeletal muscle mass/body weight) assessment. Serum samples were used to estimate CAF levelsusing enzyme-linked immunosorbent assay (ELISA).

Median CAF level was significantly higher among T2D group compared to PD and control groups (P < 0.0001). Circulating CAF levels correlated positively with age and glycated haemoglobin (HbA1c) (both, P < 0.001) and negatively with HOMA-B and muscle quality (both, P < 0.001), and sarcopenic index (P = 0.07). Multivariable analysis demonstrated that the odds of being in the highest tertile category was 7.67, 95% C.I. (2.10, 29.3) among T2D.

Circulating CAF levels were significantly higher among T2D compared to PD and control study groups along with reduced skeletal muscle quality. This suggests that the circulating CAF level has the potential to be considered as a clinical marker to evaluate sarcopenia among T2D.