Type 2 diabetes is a rapidly growing health problem, yet the available tools for diagnosis of type 2 diabetes and prediabetes are unsatisfactory. Plasma glucose measurements are imprecise measures of incipient disease and glycated hemoglobin assays are relatively insensitive and are subject to a number of interferences. Type 2 diabetes frequently is coincident with """"""""metabolic syndrome"""""""", which is characterized by co-occurrence of insulin resistance, obesity, hypertension, inflammation and oxidative stress. Oxidative stress and glycation chemistry both generate reactive oxidants and electrophilic intermediates that covalently modify proteins. We hypothesize that diabetes and pre-diabetes generate combinations of glycation, oxidative and electrophilic adduction on serum albumin and that these modification signatures can serve as biomarkers for emerging disease. In the R21 phase of this project, we will apply liquid chromatography-tandem mass spectrometry (LC-MS-MS)-based proteomics approaches to identify modified albumin forms present in plasma of individuals with normal glucose tolerance, type 2 diabetes and pre-diabetes. We will characterize relative differences in levels of the markers between sample groups and develop a prototype database of modified albumin forms and supporting datasets. In the R33 phase of the project, we will chemically characterize the markers and develop highly sensitive, specific LC-MS-MS assays for albumin adducts and evaluate the utility of these candidate markers. We also will assess the occurrence of these albumin modifications in dyslipidemias, obesity and hypertension in the absence of diabetes to evaluate the ability of these markers to distinguish type 2 diabetes from related diseases. These studies will bring the most sensitive and specific analytical proteomics technologies available to identify new markers for type 2 diabetes and pre-diabetes.
