INVESTIGATING THE INFLUENCE OF SEROTONIN AND FECAL SHORT CHAIN FATTY ACIDS (SCFAs) ON GUT MICROBIOT A BRAIN AXIS IN HEALTHY SUBJECTS

Abstract

Human digestive tract is colonized by numerous symbiotic microorganisms that possess an ability to orchestrate host metabolic and physiological process. The relative abundance of between symbionts and pathobionts in gut has a profound impact in modulation of host health and disease. The human super organism resulting from complex gut microbiota interaction with host has a profound role in human neurophysiology. Microbial metabolites are usually bioactive compound that have ability to manipulate immune system, protect gut epithe lial barrier and regulate host neuronal health . Diet and gut flora together have produced symbiotic which have been deemed effective in bidirectional communication between enteric and central nervous system. Dietary compounds that are indigestible reach unabsorbed to intestines where gut microbiota utilize them to gain energy and thereby producing end products that are hi ghly beneficial for host. These gut microbiota derived metabolites either directly or indirectly effect the crosstalk between host gut and brain via several pathways like HPA, BBB and vagal nerve. SCFAs are low molecular weight that have ability to influence the communication between gut and CNS but has demonstrated a role as neuroprotective compound. Furthermore, it triggers the production of other important neuroactive compounds such as serotonin from EC cells which have been implicated in overall health of nervous system. Imbalance in serotonin levels is usually associated with a dysbiotic gut which leads to inflammation and thereby progression of psych iatric or neurodegenerative disease. Therefore, it extremely important to understand role of such compounds in maintain homeostasis in human body. Population samples from three distinct region with a different dietary pattern and lifestyle were assessed based on effect of these patterns on their SCFAs and serotonin concentrations. Total 35 serum and fecal samples of healthy individuals were analyzed for microbiology and serotonin respectively. Highest incidence of serum serotonin was found in Sindh region mainly due to hi gher consumption antioxidant rich food. A profound impact of dietary habits was discovered on serum serotonin levels. The subsequent impact of serotonin correlated with the brain health of these individuals. It was observed that dietary patterns influence the serum serotonin levels through microbiota modulated activity which was thereby is responsible for maintaining a homeostatic balance promoting a healthy brain activity in all subjects.