Plasma Metabolomic Profiles Reflective of Glucose Homeostasis in Non-Diabetic and Type 2 Diabetic Obese African-American Women

Insulin resistance progressing to type 2 diabetes mellitus (T2DM) is marked by a broad perturbation of macronutrient intermediary metabolism. Understanding the biochemical networks that underlie metabolic homeostasis and how they associate with insulin action will help unravel diabetes etiology and should foster discovery of new biomarkers of disease risk and severity. We examined differences in plasma concentrations of >350 metabolites in fasted obese T2DM vs. obese non-diabetic African-American women, and utilized principal components analysis to identify 158 metabolite components that strongly correlated with fasting HbA1c over a broad range of the latter (r = −0.631; p<0.0001). In addition to many unidentified small molecules, specific metabolites that were increased significantly in T2DM subjects included certain amino acids and their derivatives (i.e., leucine, 2-ketoisocaproate, valine, cystine, histidine), 2-hydroxybutanoate, long-chain fatty acids, and carbohydrate derivatives. Leucine and valine concentrations rose with increasing HbA1c, and significantly correlated with plasma acetylcarnitine concentrations. It is hypothesized that this reflects a close link between abnormalities in glucose homeostasis, amino acid catabolism, and efficiency of fuel combustion in the tricarboxylic acid (TCA) cycle. It is speculated that a mechanism for potential TCA cycle inefficiency concurrent with insulin resistance is “anaplerotic stress” emanating from reduced amino acid-derived carbon flux to TCA cycle intermediates, which if coupled to perturbation in cataplerosis would lead to net reduction in TCA cycle capacity relative to fuel delivery

Therapeutic effect of glibenclamide in a fixed combination with metformin or phenformin in NIDDM patients

The combination of a sulfonylurea with a biguanide improves the pancreatic p-cell insulin secretion and the insulin utilization in peripheral tissues in NIDDM. This open, crossover, randomised and prospective study was designed to compare the effects of the fixed combination glibenclamide-metformin (GL-METF) - 2.5 and 400 mg respectively, with the fixed combination glibenclamide-phenformin (GL-PHEN) - 2.5 and 25 mg respectively, on NIDDM diabetes control. Thirty NIDDM patients, in ideal metabolic control, who were being treated with GL-PHEN were divided in two groups. One group received GL-PHEN for 12 weeks followed by 12 weeks treatment with GL-METF and the reverse treatment was given to the second group. A statistically significant decrease of post-prandial blood glucose (p = 0.034) and glycosylated haemo-globin (p &lt; 0.02) values was observed under GL-METF treatment compared to those with GL-PHEN. The values of lactic acid were within normal limits during both treatments. The insulin secretion after breakfast was similar with both drug compounds. The BMI of the patients remained the same during a follow-up study of 24 weeks. Lipid metabolism did not change significantly during the trial and the safety parameters (renal and liver function, full blood count) remained unchanged. In conclusion, the administration of GL-METF leads to better diabetes control in NIDDM patients compared to that of GL-PHEN