Intestinal Microbiome: A Step Toward Personalized Medicine?

 Natalya Alekhina

A hidden universe                   

Over the past decade, the research on the human intestinal microbiome has grown exponentially. The gut has transformed from the body's most underrated organ to an unexplored universe of trillions of microbial species that engage in complex interactions with one another and the human host. While much about the composition of the microbiome and the intricate mechanisms guiding the interactions between the microbiome and immune system remain unknown, an increasing amount of research studies point to the significant role intestinal microbes play in many essential bodily functions including inflammation, metabolism, and even mood.

A shifting paradigm

My initial interest in the intestinal microbiome was spiked by a brilliant and witty book by Giulia Enders eloquently titled “Gut”. Dr. Enders embarks on a captivating journey through the digestive tract exploring the microscopic processes that take place in the gut and have a very significant effect on the overall health of the organism. It turns out that gut-healthy foods are essential not only for bowel regularity but also for nourishing the right kind of bacteria in the digestive tract that can protect their host from inflammation, leaky gut syndrome, obesity, and even cancer. A whole industry that emerged around probiotics, prebiotics, synbiotics, functional nutrition, and digestive enzymes is a manifestation of the paradigm shift in how the microbiome is perceived.

Exploring the unknown

The National Institutes’ of Health Human Microbiome Project conducted between 2007 and 2016, was one of the initial attempts to understand the microbial composition of the human microbiome and to establish the connection between microbial diversity and certain chronic conditions in human hosts. Though this extensive study has shed some light on the complexity of the microbiome, many of the insights gained in the process generated additional questions. Is there such thing as a "normal" or "standard" microbiome? How do foods we eat and medications we take affect the microbial diversity of the digestive tract? Can other factors such as the host's age, gender, ethnicity, exercise habits, chronic health conditions, and diet alter the composition of the microbiome? And most importantly, can the intestinal microbiome be manipulated to improve health outcomes? Studies on fecal microbiome transplant (FMT) in patients with antibiotic-resistant Clostridium difficile colitis suggest that this is indeed possible.

What is next?                            

 

 Though FMT is an expensive and invasive procedure, it holds the promise of using microbiome manipulation as a potential avenue for the treatment of certain medical conditions. With this in mind, new intriguing avenues of microbiome research are being explored, such as the connection between microbiome composition and obesity, the role of gut bacteria in the incidence of certain cancers, the effects of the maternal microbiome on newborn's gut health, and the "gut-brain" connection to name a few. While these topics are still there for microbiome researchers to ponder, one thing appears clear: we are witnessing a paradigm shift in how the intestinal microbiome is perceived and studied, with new insights bridging the gap between research and personalized medicine.

References

Enders, Enders, J., & Shaw, D. (2015). Gut. Greystone Books.

Ideacity. (2017, August 30). Giulia Enders | The Secret Life of the Gut [Video]. YouTube. https://www.youtube.com/watch?v=BJ-C99FwRHQ

NIH Human Microbiome Project - Home. (2007). Human Microbiome Project Data Portal. Retrieved April 13, 2022, from https://hmpdacc.org/