Tuberculosis-related Mood Disorders: Probiotics as a Next-Generation Strategy

Abstract

Introduction: Tuberculosis-related mood disorders are well-known but least researched. As frequent comorbidity of tuberculosis (TB), depression is linked to poor adherence to treatment for a number of illnesses. The exact causal mechanism and pathways behind TB disease and associated mental illnesses are unclear. The disease's severity and duration impact the occurrence of depression, and MDR-TB enhances this risk. To summarise the information on the association between depression and unfavourable outcomes of TB treatment, we carried out a narrative review. Objective: The objective of this study is to provide an overview of probiotics as a cutting-edge treatment for mood disorders linked to tuberculosis. Methods: A systematic stepwise online database research was done for systematic reviews, original studies, and review papers published on probiotics and mental disorders associated with tuberculosis in PubMed/MEDLINE, Google Scholar, and Web of Science. The reference lists for these articles were also used as sources for the bibliography Results: The gut microbiota and the brain are connected by neuroendocrine-immune pathways. The diversity and abundance of microbiota Proteobacteria, Actinobacteria Bacteroides, and Firmicutes are reduced in tuberculosis patients. Through the stimulation of different immunological responses or visceral sensory pathways, these changes in the gut microbiome may be a contributing factor in emotional instability and mood disorders. Probiotics also lessen the stress response caused by cortisol, in addition to releasing neurotransmitters, including GABA, serotonin, noradrenaline, acetylcholine, and dopamine, in various brain regions. Probiotics are the most prevalent in the sensory brain network of the brain, which controls the brain's core processing of emotions and sensations. In addition, they produce short-chain fatty acids (SCAFs) from the bacterial fermentation of fibre in the colon, such as butyrate, which inhibits histone deacetylase, binds to G protein-coupled receptors, and serves as an energy metabolite. Butyrate plays a significant role in maintaining brain health by having antimanic and antidepressant effects. Several clinical research on patients with MDD has revealed that probiotics have favourable effects on depressive symptoms. Conclusion: The central dopamine system, inflammation, the BDNF system, and the gut-brain axis are all recognised to play crucial roles in the pathogenesis of MDD. Commercial probiotics that generate butyrate-producing SCFAs and those resistant to metabolic disorders (such as Bacteroidetes) may be beneficial for tuberculosis-related MDD during and after treatment. In this situation, using bacteria that produce SCFA could be a cutting-edge method of treating clinical MDD.