Study analyzes children’s gut bacteria; finds promise that early intervention might prevent disease

For every cell in our bodies that makes us human, 10 bacteria ride along to help determine how healthy a human we become. Most of them live in our intestines.Scientists, who have identified about 10,000 species of gut bacteria, are beginning to discover the intricate relationships between those microbes and how their imbalance may trigger human diseases. Generally, investigators have believed that such a microbiota map is drawn by the time a child is two years of age – a result of genetics, diet, how she was born (delivered), when and how frequently she used antibiotics, and other factors.

Now, public health research led by a University of North Carolina at Chapel Hill faculty member adds credence to the idea that certain interventions may be used to correct microbial imbalances in children and that the window of time during which to make those adjustments may be longer than previously thought. These “windows of opportunity,” the study reports, may be used to “promote health and prevent or mitigate disease processes.”

The study, led by Tamar Ringel-Kulka, MD, MPH, research assistant professor of maternal and child health at Gillings School of Global Public Health, was published online May 23 in the journal PLOS One.

Ringel-Kulka and colleagues characterized the composition of intestinal microbes in 51 subjects from a single geographical region in the U.S. – central North Carolina – and specifically compared the microbes and their environment, or the microbiome, from healthy children ages 12 to 48 months with that of healthy adults, ages 21 to 65 years.

Using a technology called the human intestinal tract chip (HITChip), the researchers, in collaboration with investigators at the University of Finland and Wageningen University in the Netherlands, conducted a phylogenetic mircroarray analysis, that is, they examined the biochemical structures to determine the structures’ genetic history and evolution.

The researchers extended their analysis beyond children who previously had been studied (those up to age two) to include three- and four-year-olds. Their findings suggest that the peak of bacterial diversity is not yet reached at these young ages, likely because the “accumulation of environmental and dietary exposures over time leads to an increase in diversity with age.”

It is known that low microbial diversity in adults has been associated with certain disease conditions including inflammatory bowel diseases and irritable bowel syndrome.

 

In children, emerging data suggest that compositional changes in gut bacteria in early life later may lead to disease development. The use of antibiotics early in life, for instance, is associated with increased risk for asthma and Crohn’s disease in late childhood and adulthood. Infants’ reduced diversity in intestinal bacteria is associated with higher risk for allergic rhinitis as the child grows, and lower levels of one microbe – Bifidobacteria – are associated with overweight at age 7.

 

The lack of maturity and diversity of the child’s gut bacteria suggests that the intestinal microorganisms still may be vulnerable to external exposures. The positive side of the vulnerability, however, is that there may be a period at an early age during which interventions may be made to prevent disease or improve the likelihood of health.With additional research, the authors aim to better understand the colonization process through early and late childhood. Future studies, the authors state, should take into account factors such as diet, gut physiology and other variables, which may contribute to establishment/colonization of intestinal microbes.

 

In addition to Ringel-Kulka, study co-authors are Jing Chen, MSc, Jarkko Salojärvi, PhD, Airi Palva, PhD, Willem M. de Vos, PhD, and Reetta Satokari, PhD, of the University of Helsinki (Finland) Department of Veterinary Biosciences in the Division of Microbiology and Epidemiology; and Yehuda Ringel, MD, and Ian Carroll, PhD, of the University of North Carolina at Chapel Hill’s Division of Gastroenterology and Hepatology in the School of Medicine. Willem de Vos also is affiliated with the Haartman Institute at the University of Helsinki and the laboratory of microbiology at The Netherlands’ Wageningen University.The study, “Intestinal Microbiota in Healthy U.S. Young Children and Adults – a High Throughput Microarray Analysis,” is available online.

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Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or dpesci@unc.edu.