Gut microbiota: a new aspect that should be taken into more consideration when assessing the toxicity of chemicals or the adverse effects and efficacy of drugs

Pharmacological Efficacy/Toxicity of Drugs: A Comprehensive Update About the Dynamic Interplay of Microbes

Oral ingestion is a common, easy to access, route for therapeutic drugs to be delivered. The conception of the gastrointestinal tract as a passive physiological compartment has evolved toward a dynamic perspective of the same. Thus, microbiota plays an important role in contributing with additional metabolic capacities to its host as well as to its phenotypic heterogeneity. These adaptations in turn influence the efficacy and toxicity of a broad range of drugs. Notwithstanding, xenobiotics and therapeutic drugs affecting the microbiome's activity also significantly impact metabolism affecting different organs and tissues, and thereby drugs' toxicity/efficacy effects. Other physiological interfaces (i.e., gut, lungs, and skin) also represent complex media with features about microbiota's composition. In addition, there have been described key regulatory effects of microbes on immunotherapy, because of its potential harnessing the host immune system, mental disorders by modulating neuroendocrine systems and cancer. These alterations are responsible of physiological variations in the response(s) between individuals and populations. However, the study of population-based differences in intestinal microbial-related drug metabolism has been largely inferential. This review outlines major reciprocal implications between drugs and microbes regulatory capacities in pharmacotherapy.

Etiology of inflammatory bowel disease: a unified hypothesis

Inflammatory bowel disease (IBD), including both ulcerative colitis (UC) and Crohn's disease (CD), emerged and dramatically increased for about a century. Despite extensive research, its cause remains regarded as unknown. About a decade ago, a series of findings made me suspect that saccharin may be a key causative factor for IBD, through its inhibition on gut bacteria and the resultant impaired inactivation of digestive proteases and over digestion of the mucus layer and gut barrier (the Bacteria-Protease-Mucus-Barrier hypothesis). It explained many puzzles in IBD such as its emergence and temporal changes in last century. Recently I further found evidence suggesting sucralose may be also linked to IBD through a similar mechanism as saccharin and have contributed to the recent worldwide increase of IBD. This new hypothesis suggests that UC and CD are just two symptoms of the same morbidity, rather than two different diseases. They are both caused by a weakening in gut barrier and only differ in that UC is mainly due to increased infiltration of gut bacteria and the resultant recruitment of neutrophils and formation of crypt abscess, while CD is mainly due to increased infiltration of antigens and particles from gut lumen and the resultant recruitment of macrophages and formation of granulomas. It explained the delayed appearance but accelerated increase of CD over UC and many other phenomena. This paper aims to provide a detailed description of a unified hypothesis regarding the etiology of IBD, including the cause and mechanism of IBD, as well as the relationship between UC and CD.