Overviews of how human health is affected by host and microbiome activity are presented in three papers by the integrative Human Microbiome Project (iHMP), published online in Nature and Nature Medicine this week. This initiative investigated changes in the microbiome and host in inflammatory bowel disease (IBD), prediabetes, and pregnancy and preterm birth. The findings help efforts to characterize these conditions and predict patient outcomes, and may in the future contribute to treatment.
The human microbiome (the genomes of microorganisms that reside within the human body) varies between individuals, populations and environments, and is known to influence human health and disease. The iHMP explores the temporal dynamics of the microbiome and host (such as immune responses and metabolism) using multi-omic methods in order to understand the microbial-host interplay in these conditions.
Curtis Huttenhower and colleagues studied 132 individuals with IBD and healthy control participants. In a Nature paper, the authors identify alterations in the composition of the microbiome, changes in host- and microbiome-derived molecules in the gut, and shifts in gene expression. The study provides the most comprehensive description to date of host and microbial activities in IBD and could provide insights into disease onset and progression, the authors conclude.
In a second Nature paper, Michael Snyder’s group reports the interplay between host and microbiome activity in prediabetes - a condition that can lead to type 2 diabetes, but is often undiagnosed. The researchers studied 106 healthy and prediabetic individuals over four years, analysing molecular, genetic and microbial changes. They discovered patterns that define early disease development, which may enable early detection of type 2 diabetes in some cases.
A paper in Nature Medicine describes the contribution of the vaginal microbiome to the risk of premature birth, the incidence of which is over 10% worldwide. Gregory Buck and colleagues studied 1,527 women through pregnancy, revealing changes in the vaginal microbiome associated with risk of preterm births (at less than 37 weeks’ gestation), particularly in women of African descent. For example, women who delivered preterm had lower levels of Lactobacillus crispatus, previously reported to be associated with women's health, than those who had full-term pregnancies. They also identified a number of different bacteria that were over-represented in women who delivered preterm. This work may aid future efforts to predict preterm birth early in pregnancy.
The project is also discussed in a Perspective article and Comment piece.