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ARS Home » Pacific West Area » Davis, California » Western Human Nutrition Research Center » Obesity and Metabolism Research » Research » Research Project #436046

Research Project: Drug-Vitamin Interactions Mediated by the Thiamine Transporter, SLC19A3

Location: Obesity and Metabolism Research

Project Number: 2032-51530-025-14-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Feb 1, 2019
End Date: Apr 30, 2020

Objective:
Recent findings suggest that metformin and other medications commonly used in the overwieght/obese population, can inhibit SLC19A3-mediated intestinal absorption of thiamine resulting in a previously unrecognized drug-vitamin interaction. This drug-vitamin interaction can contribute to thiamine deficiency associated with various diseases present in the obese population, including metformin-induced hyperlactatemia and lactic acidosis. At University of California, San Francisco, efforts will be made to understand the scope of compound classes that can interact with this transporter, and evaluate their efficacy in a humanized mouse model in collaboration with Tufts University. At the Western Human Nutrition Research Center (WHNRC), targeted profiling of B1 vitamers will be used to evaluate impact on thiamine uptake and metabolism and the variance of this response in healthy individuals, while metabolomics will be used to determine if a pre-deficiency metabolic signature exists which reflects a reduction in the activity of enzymes dependent on thiamine pyrophosphate (TPP), the active metabolite of thiamine.

Approach:
To assess the variability in individual metformin-thiamine interactions, thiamine vitamer pharmacokinetics will be characterized in healthy volunteers. Using a randomized crossover study design in healthy volunteers, (a) determine the effects of metformin on the absorption and disposition of thiamine and its major metabolites and (b) explore metabolic signatures reflecting the activity of TPP-dependent enzymes following administration of thiamine, metformin and thiamine plus metformin. In particular, we will determine the pharmacokinetic properties of thiamine, and its two major metabolites, TMP (thiamine monophosphate), and TPP in healthy volunteers treated with thiamine (orally) alone and thiamine plus metformin. Key metabolites and metabolic ratios associated with TPP-dependent enzymes will be measured.