HOW MICROBIOTA INFLUENCES HEALTH AND DISEASE? - by Dr.T.V.Rao MD

HOW MICROBIOTA INFLUENCES HEALTH AND DISEASE? - by Dr.T.V.Rao MD We the humans and many little creatures too are diverse, it was though in the past Genes alone made the difference to species, and differentiated to many Phyla and families, we are familiar with Major histocompatibility complex, and the understanding was better when we started doing transplantation and more thinking started with cancer biology. Today the thinking on human disease, survival and cure of many diseases is changing towards understanding the little one as we call as normal flora (Micro biota) colonising the humans. The word micro biota represents an ensemble of microorganisms that resides in a previously established environment. The human body is colonized by a vast number of microbes, collectively referred to as the human microbiota. The link between these microbes and our health is the focus of a growing number of research initiatives, and new insights are emerging rapidly Human beings have clusters of bacteria in different parts of the body, such as in the surface or deep layers of skin (skin microbiota), the mouth (oral micro biota), the vagina (vaginal micro biota), and so on. Microbes associated with the human body include eukaryotes, archaea, bacteria and viruses, with bacteria alone estimated to outnumber human cells within an individual by an ordered of magnitude. Our gut microbiota contains tens of trillions of bacteria – ten times more cells than in our body. Our knowledge of these communities and their gene content, referred to collectively as the human micro biome, The US NIH-funded Human Micro biome Project Consortium (HMP) brought together a broad collection of scientific experts to explore these microbial communities and their relationships with their human hosts. Human’s health today guided by normal flora as is defined today as Micro biota which has greater influence on health and disease, the human gut is the greatest colonisers of many bacteria, is home to trillions of microorganisms, and there is vast diversity within this gut micro biota. Research into the association of the gut micro biota with health and disease (including, among others, diet and nutrition, obesity, IBD and cancer) continues to expand, with the field advancing at a rapid pace. The complex microbial communities that reside on or within the human body have a vital role in health and disease. Interest in the gut micro biota—arguably the highest density of micro-organisms in the human body—has rapidly increased in the past few years. It contains tens of trillions of microorganisms, including at least 1000 different species of known bacteria with more than 3 million genes (150 times more than human genes). Microbiota can, in total, weigh up to 2 kg. One third of our gut microbiota is common to most people, while two thirds are specific to each one of us. In other words, the microbiota in your intestine is like an individual identity card. Furthermore, the advent of advanced Meta genomic sequencing has finally enabled the diversity within the gut micro biota to be fully appreciated; the majority of bacteria resident in the gut are not easily cultured using traditional microbiological techniques. Testament to the importance of the gut micro biota in human disease is the growing number of conditions now linked to dysbiosis of the resident micro biota, including, amongst others, IBD, cancer, obesity, neurological diseases and cardiovascular disease. As we come to accept the gut micro biota as a human microbial 'organ' central to human health and disease, understanding the host–micro biota relationship is vital, and targeting the gut micro biota is likely to become a future therapy for a number of conditions. Just how we can manipulate the resident gut micro biota to our benefit is yet to be fully determined, but new insights are emerging rapidly and ongoing research is needed. More than 1,000 different known bacterial species can be found in human gut microbiota, but only 150 to 170 predominate in any given subject. The changing composition of the human micro biota is linked with alterations in human behaviour and the rising prevalence of immunoallergic and metabolic disorders. The composition of our microbiota evolves throughout our entire life, from birth to old age, and is the result of different environmental influences. Gut micro biota’s balance can be affected during the ageing process and, consequently, the elderly have substantially different microbiota to younger adults. Although it can adapt to change, a loss of balance in gut microbiota may arise in some specific situations. This is called dysbiosis. Dysbiosis may be linked to health problems such as functional bowel disorders, inflammatory bowel disease, allergies, obesity and diabetes. Use of Antibiotics has counterproductive effect on the Gut flora. However, the effect of antibiotics on the intestinal microbiota has not been extensively scrutinized other than in studies on the induction of antibiotic resistance in commensal bacteria following treatment. The studies show that microbiota imbalance predisposes the host to more severe enteropathogenic infections including Pseudomembranous colitis. The peer reviewed observations could be part of the explanation for the high rates of nosocomial infections, when antibiotics are abundantly used, makes many venerable to morbidity and mortality. In the past only Immunology was though as an important factor protecting the humans however the current science is changing that Immunology with normal Microbiota makes the difference in human survival. (Read the Special issues in Nature)

Dr.T.V.Rao MD Professor of Microbiology Freelance writer.