Evidence of higher intramyocellular fat among normal and overweight Indians with prediabetes

Authors : Sucharita S, Pranathi R, Correa M, Keerthana P, Ramesh LJ, Bantwal G, Venkatappa HM, Mahadev KP, Thomas T, Bosch RJ, Harridge SDR, Kurpad AV

Publication Year : 2019

Abstract :

The rise in prevalence rates of Type 2 Diabetes among Indians is well recognized. The research focus has been primarily to understand the changes in insulin sensitivity and beta cell dysfunction among Indians with Type 2 Diabetes. However, no data are available on the role of peripheral tissue, in particular intramyocellular lipid (IMCL) content and its impact on glucose homeostasis among Indians with prediabetes.

28 male subjects (20-40 year) were studied. 13 with prediabetes (BMI ranging from 25.4 ± 2.9 kg/m2) and 15 controls (BMI ranging from 24.6 ± 2.8 kg/m2) were recruited. Body composition by dual energy X-ray absorptiometry (DXA), insulin sensitivity, insulin secretion rates were derived using the minimal model of C-peptide secretion and kinetics rates and skeletal muscle strength of the lower limb (quadriceps) was assessed using Isokinetic dynamometry. From muscle biopsy samples of the vastus lateralis, IMCL fat content (Oil red O staining) was determined.

The prediabetes group were older compared to controls (P less than 0.01), but had similar BMI. The muscle to fat ratio, plasma Insulin, C peptide, HOMA-IR and HOMA % B were also comparable between the groups. IMCL fat content (%) was significantly higher in the prediabetes group compared to controls (7.0 ± 0.7% vs. 2.0 ± 0.3%, P less than 0.01). This difference persisted even after controlling for age. Overall the IMCL fat content (%) was positively and significantly associated with HbA1c (r = 0.76, P less than 0.01). HOMA-IR was significantly correlated with central (android, trunk) adiposity (kg) (r = 0.71, P less than 0.01) but not with IMCL (%).

This is the first direct evidence of existence of significantly higher lipid levels within skeletal muscle cells among normal and overweight young Indians with prediabetes. However, there was no association between IMCL and HOMA-IR among the prediabetes group.