Plasma proteome changes in subjects with Type 2 diabetes mellitus with a low or high early insulin response

Circulating proteins contribute to the pathogenesis of T2DM (Type 2 diabetes mellitus) in various ways. The aim of the present study was to investigate variations in plasma protein levels in subjects with T2DM and differences in beta-cell function, characterized by the EIR (early insulin response), and to compare these protein levels with those observed in individuals with NGT (normal glucose tolerance). Ten subjects with NGT+high EIR, ten with T2DM+high EIR, and ten with T2DM+low EIR were selected from the community-based ULSAM (Uppsala Longitudinal Study of Adult Men) cohort. Plasma protein profiling was performed using SELDI-TOF (surface-enhanced laser-desorption ionization-time-of-flight) MS. In total, nine plasma proteins differed between the three study groups (P<0.05, as determined by ANOVA). The levels of two forms of transthyretin, haemoglobin alpha-chain and haemoglobin beta-chain were decreased in plasma from subjects with T2DM compared with subjects with NGT, irrespective of the EIR of the subjects. Apolipoprotein H was decreased in plasma from individuals with T2DM+high EIR compared with subjects with NGT. Four additional unidentified plasma proteins also varied in different ways between the experimental groups. In conclusion, the proteins detected in the present study may be related to the development of beta-cell dysfunction.