Effects of oral-glucose load on the gene expression of peripheral blood mono-nuclear cells in Asian-Indian men.

The objective of this study was to perform a global, non-targeted gene expression analysis by microarray, to understand the immune cell gene regulation at fasting and in response to oral glucose load and how this regulation is different in Asian-Indian men with normal glucose tolerance (NGT) and pre-diabetes (PD). Through observing real-time gene expression changes, this study highlights 1. the importance of acute metabolic challenges like oral glucose load in regulating the immune cell gene expression and function. 2. How insulin resistance and pre-diabetes causes severe perturbation of baseline gene expression and thus alters the response to oral glucose load as well. PBMCs were isolated from fasting (8-12 hours) and 2 hour-post 75 gm. oral glucose load blood samples of healthy (NGT) and pre-diabetic (PD) Asian-Indian men. RNA was isolated and after due quality check, was used to hybridize on the array. A total of 28 RNA samples were hybridized (6 NGT fasting samples, 6 NGT 2-hour samples, 9 PD fasting samples and 7 PD 2-hour samples). A total of three comparisons were carried out in this study, listed as follows : 1) 2-hour post glucose load versus fasting (control) in NGT subjects with fold change cut-off >1.5 and p value cut-off of < 0.05 in paired Student’s t-test, 2) 2-hour post glucose load versus fasting (control) for PD with fold change cut-off >1.5 and p value cut-off of < 0.05 in paired Student’s t-test and 3) fasting PD versus fasting NGT (control) with fold change cut-off >2.0 and p value cut-off of < 0.05 in un-paired Student’s t-test