Context: Metabolomic profiling of amino acids and acylcarnitines has revealed consistent patterns associated with metabolic disease.
Objective: This study used metabolomic profiling to identify analytes associated with insulin sensitivity (SI) and conversion to type 2 diabetes (T2D).
Design: A multiethnic cohort from the Insulin Resistance Atherosclerosis Study.
Patients: A total of 196 subjects (European American, Hispanic, and African American) were selected to represent extremes of the SI distribution and conversion to T2D between baseline and followup exams.
Main outcome: Mass spectrometry-based profiling of 69 metabolites. Subjects participated in a frequently sampled i.v. glucose tolerance test to measure SI and acute insulin response. T2D status was determined by a 2-hour oral glucose tolerance test.
Results: Logistic regression analysis from 72 high and 75 low SI subjects revealed significantly decreased glycine and increased valine, leucine, phenylalanine, and combined glutamine and glutamate (P = .0079-7.7 × 10(-6)) in insulin-resistant subjects. Ethnic-stratified results were strongest in European Americans. Comparing amino acid profiles between subjects that converted to T2D (76 converters; 70 nonconverters) yielded a similar pattern of associations: decreased glycine and increased valine, leucine, and combined glutamine and glutamate (P = .016-.00010). Importantly, β-cell function as a covariate revealed a similar pattern of association.
Conclusions: A distinct pattern of differences in amino acids were observed when comparing subjects with high and low levels of SI. This pattern was associated with conversion to T2D, remaining significant when accounting for β-cell function, emphasizing a link between this metabolic profile and insulin resistance. These results demonstrate a consistent metabolic signature associated with insulin resistance and conversion to T2D, providing potential insight into underlying mechanisms of disease pathogenesis.