Science

Milestone study links patterns of gut bacteria genes to several human diseases

Milestone study links patterns...
New research affirms how astonishingly complex the relationship between our general health and the trillions of micro-organisms living in our gut is
New research affirms how astonishingly complex the relationship between our general health and the trillions of micro-organisms living in our gut is
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New research affirms how astonishingly complex the relationship between our general health and the trillions of micro-organisms living in our gut is
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New research affirms how astonishingly complex the relationship between our general health and the trillions of micro-organisms living in our gut is

There are trillions of micro-organisms living inside every one of us. Most of these tiny tenants reside in our gut, and perhaps one of the most important medical discoveries of the past few decades has been understanding just how much of a role these organisms play in our general health and well-being.

Exactly how the bacteria living in our gut influences disease is a question many researchers are trying to answer. However, unpacking the vast complexity of the human microbiome is proving to be an immense challenge.

Chirag Patel, from Harvard Medical School's Blavatnik Institute, has been working for years to try and find connections between bacterial composition in the gut and human disease. In 2019 Patel and colleagues published their first study attempting to catalog all the genes in the collective human microbiome.

This initial study reported an astounding 46 million genes, chronicled from just 3,500 human microbiome samples. Even more striking was the finding that around half of all those genes identified were unique to a single human microbiome sample.

The stunning genetic diversity detected in this early study suggested every person’s microbiome could be so unique there may be no universal "one-size-fits-all" approach to targeting gut bacteria for disease treatment. The complex nature of microbiome science may be daunting to some but Patel and colleagues from Harvard Medical School and the Joslin Diabetes Center were up for the challenge, seeing this as a biostatistics problem that can be solved by finding the right computational model.

“The ultimate goal of computational science is to generate hypotheses from a huge swath of data,” explains Braden Tierney, first author on the new study. “Our work shows that this can be done and opens up so many new avenues for research and inquiry that we are only limited by the time, people, and resources needed to run those tests.”

Instead of trying to home in on single bacterial species that correlates with a certain disease in everyone – a possibly futile pursuit – the new study introduces the concept of “microbiome architectures”. These are collections of microbial features that can be more universally linked with certain diseases.

“… we compute architecture by identifying the complete set of associations between the microbiome and a given host disease,” the researchers write in the study. "The concept and construction of architectures sidesteps the challenge of building grand views of a 'normal' microbiome. Architectures instead enable the identification of specific (but still holistic) microbial factors associated with specific host phenotypes across sources of metagenomic variation.”

The new study set out to identify patterns of bacterial genes that could be linked to certain human diseases. Seven specific human diseases were chosen for this particular study, including type 2 diabetes, colorectal cancer and atherosclerotic cardiovascular disease.

Specific clusters of bacterial genes were found to consistently correlate with various diseases. Interestingly, heart disease, inflammatory bowel disease, and liver cirrhosis all shared strikingly similar genetic signatures, suggesting gut bacteria may play a role in the development of these diseases.

The research also found no consistent association between a bacterial species called Solobacterium moorei and colon cancer. This counters prior research detecting a link between that species and colon cancer.

However, particular genes from a subspecies of Solobacterium moorei could be reliably associated with colon cancer. Patel notes this discovery affirms specific bacterial strains and gene signatures are more relevant to human disease risk than general bacterial families.

“This opens a window for the development of tests using cross-disease, gene-based indicators of patient health,” says Tierney. “We’ve identified genetic markers that we think could eventually lead to tests, or just one test, to identify associations with a number of medical conditions.”

The new research explicitly makes clear it was not designed to offer insights into how certain bacteria could play a role in the development of disease. Future research will have to dig into those questions. Instead, this work is looking to find universal patterns of bacterial genes that correlate with disease in order to inform future research, and possibly influence the development of novel diagnostic tools.

The new study was published in Nature Communications.

Source: Harvard University

5 comments
5 comments
BlueOak
About all this does is expose how massively complex the human body is.

The study picked seven diseases and went looking for gut bugs. Hardly proves anything since it might the reverse of cause and effect... the gut bugs might simply be there as a result of the diseases rather than those bugs *causing* the diseases. Yawn...
Ornery Johnson
Blue Oak, the authors specifically state that their research was not attempting to definitively link any particular bacterial species to a given disease. They simply say that their techniques may allow further research that can more definitively look at whether such "associations" are actually caused by the presence of these bacteria.
Karmudjun
An interesting report here Rich, Thanks!
You have to hand it to Harvard to look beyond our complexity and investigate how the microbiome matches up with various diseases afflicting humankind. Not only looking into the microbiome complexity - but drilling down into the actual genetic strains of the gut biome. We are indeed hosts for more cells in our gut than we have cells in our body, but seeking correlation between different strains of the same bacteria and incidence of illness? Awesome.
The immense impact of this study will be seen in years to come as more advanced research in other locations increase the statistical strength of these studies. As we may all know - or not - stress causes stomach ulcers and "yawn" Helicobacter pylori is implicated - but what genes of H. pylori are expressed in the incidences of ulceration? More research required and more cohorts needed to verify any such findings. Since we've known about the bacterial milieu and incidence of diseases for more than a decade, I'm glad the associations addressed here were statistically analyzed even if they were drilling into the bacterial genes expressed rather than the actual presence of the bacteria. Good findings. Some may dismiss - but each refined research finding furthers our knowledge and maybe will improve your children's lives.
PassingBy2
Wild guess?
It's not just 'humans' with gut bacteria?
Ron Grace
Exciting new developments ,wish the research “Luck”?in their future work.