Gut Microbiome and Pharmacokinetic Variability in Tuberculosis and Diabetes

PROJECT SUMMARY/ABSTRACT There are significant knowledge gaps in understanding the mechanisms and biological predictors of low drug exposures and treatment failure in patients with tuberculosis (TB) and type 2 diabetes mellitus (DM). To address the impact of DM on poor TB outcomes, we propose an interdisciplinary mentored research and training plan to investigate gut microbiome-mediated variation of anti-TB drug pharmacokinetics (PK) in DM and non-DM TB patients in an ongoing prospective, observational PK trial investigating isoniazid, rifampin, and pyrazinamide in TB patients. Specific Aim 1 will quantify the effect of DM and gut microbiota alpha diversity on the bioavailability of oral anti-TB drugs in patients treated for active TB, by linking pharmacometric modeling with DM and measures of the gut dysbiosis in active TB patients with and without DM. Specific Aim 2 will characterize the relationship of gut microbiota alpha diversity and diabetes in patients with active TB, by conducting a comprehensive prospective analysis of the human gut microbiome from clinical stool specimens. Upon successful completion of the proposed K23 research, we expect our contribution to 1) establish the previously undescribed impact of the human gut microbiome as a significant covariate to explain the heterogeneity of drug PK in patients receiving active TB treatment and, 2) demonstrate the distinctive relationship between DM and gut microbiome diversity and composition among patients with TB. These contributions will be significant because they are expected to provide strong scientific justification for a novel mechanism for the previously unexplained variability of anti-TB drug PK and TB treatment response among patients with TB/DM. The proposed research is innovative because it aims to identify the gut microbiome as a novel mechanism underlying the heterogeneity of anti-TB drug PK. The overall goal of this K23 proposal is to train Navaneeth Narayanan, PharmD, MPH for a career as an independent investigator in pharmacomicrobiomics, the study of the effect of microbiome variation on therapeutic response by regulating drug PK and pharmacodynamics (PD), with a specific career emphasis on the treatment and outcomes of TB and other infectious diseases. The career development plan includes training in human microbiome research, under the mentorship of Dr. Martin Blaser, and pharmacometrics, an interdisciplinary science of quantitative clinical pharmacology and systems biology that involves expertise in mathematical modeling to characterize and predict drug PK and PD. Dr. Narayanan will also be mentored by Dr. Scott Heysell, an international expert in anti-TB pharmacology and TB clinical research. The proposed K23 project will provide an integrated plan of mentored patient-oriented research, career development activities, and formal training in microbiome research and pharmacometrics. Guided by expert mentors and collaborators, the research and training activities outlined in this application will enable Dr. Narayanan to mature into an independent clinical/translational researcher. These opportunities will equip this investigator with a larger set of skills to answer important and novel questions about global infectious diseases.