NMR based human gut metabolomic profiling reveals altered metabolites associated with pulmonary and extra-pulmonary...

Tuberculosis remains one of the world's deadliest infectious diseases. The pathophysiology of the two manifestations of Mycobacterium tuberculosis infection, pulmonary TB (PTB) and extrapulmonary TB (EPTB) is still not fully understood. Understanding the metabolic profile of both disease manifestations in patients is important for developing therapeutic approaches and molecular diagnosis.

The current study aimed to elucidate differences in the gut metabolic profile of PTB and EPTB patients compared to healthy controls (HCs).

We used an untargeted approach through ¹H Nuclear Magnetic Resonance (NMR) spectroscopy to perform metabolomic profiling of stool samples from 77 TB patients [pulmonary TB (PTB, n = 33), cervical lymph node TB (CrLNTB, n = 30), abdominal TB (ATB, n = 14)], and 30 HCs. Multivariate and univariate analyses were performed to identify the differential gut metabolites associated with TB patients.

PTB patients showed greater metabolic perturbation than either EPTB group, with 24 metabolites significantly altered compared to 13 in ATB and 12 in CrLNTB, relative to HCs (adjusted p < 0.05). Each TB subtype displayed distinct metabolic profiles, yet several metabolites were commonly altered across all TB groups, including valine, N-formyl-L-methionine, choline, dimethylsulfone, tryptophan, valerate, N-acetylglutamate, creatine, and malonate. In the combined TB cohort versus controls, the most discriminatory metabolites were valine and N-formyl-L-methionine (AUC ≥ 0.80). Overall, these findings offer insights into the gut metabolome of TB patients in India and characterize for the first time metabolic perturbations in EPTB patients.

The study highlights the metabolic disruptions associated with PTB and EPTB patients.