Page 4 - Introduction to FMT

FMT Introduction

Core tip: Fecal microbiota transplantation (FMT) achieved a successful cure rate in recurrent Clostridium
difficile infection. Although there is a deficiency of randomized controlled trials, the present review
reveals that FMT could be a promising rescue therapy in extra-intestinal disorders associated with gut
microbiota, including metabolic diseases, neuropsychiatric disorders, autoimmune diseases, allergic
disorders, and tumors.

INTRODUCTION

The human intestinal tract is home to up to 10 microbes, outnumbering human cells within our bodies by
tenfold[1,2]. The number and diversity of bacteria differ according to the different anatomical areas,
ranging from the proximal to the distal gastrointestinal tract, with the colon harboring most of the
intestinal microbiota[3]. Such an environment developed by host-bacteria associations is termed as being
mutualistic. Four predominant bacterial phyla are identified in the human intestine: Bacteroidetes,
Firmicutes, Actinobacteria, and Proteobacteria[4].

Rather than simply occupying space in our bodies, the intestinal microbiota is essential to nutrient
metabolism, opportunistic pathogens defense[5], immune system development, and intestinal-barrier
function regulation[3,6,7]. The specific balance of intestinal microbial diversity differs by individual
according to variations (such as sanitation, social behaviors, and genetics)[8,9]. The beneficial balance of
the intestinal microbial ecosystem can be disrupted by a series of factors, which includes antimicrobial
drugs, vaccination, and dietary shifts[3]. Previous studies have suggested that intestinal microbiota
alterations have been implicated in many gastrointestinal diseases and even systemic illnesses, such as
metabolic diseases[10,11], neuropsychiatric conditions[12], autoimmune diseases[13], allergic disorders[14],
and tumors[15].

FMT Introduction