How microbes shape human health: an interview with Andrei Osterman
In his work on the human microbiome, Sanford Burnham Prebys professor Andrei Osterman, Ph.D., has shown how the organisms living within us can be leveraged to boost human health for a humanitarian cause – the plight of malnourished children.
Describe your research aimed to improve the gut microbiome in malnourished children.
In infants, it’s been well-established that conditions of severe poverty and food insecurity cause a delayed development of gut microbes, and that this results in stunted growth, numerous syndromes, and even death. My team has been collaborating with researchers at Washington University in St. Louis to develop foods that are designed to enhance the microbiome, and we’ve found that these can actually work to correct some of these pathologies.
One study involved introducing microbes from undernourished Bangladeshi children into the guts of mice. When these mice were then fed a typical Bangladeshi diet, they exhibited a weaker immune response to the oral cholera vaccine. More importantly, this poor response could be repaired by establishing a more normal gut microbiome in the mice and providing them supplements to boost these microbes’ propagation.
What else can we learn from this research that could be applied more broadly?
From a humanitarian perspective, the progress we’ve made is so valuable that there is no question we will continue the work. But studying the microbiome in infants, regardless of their food security, can also provide us with new insights into the importance of the microbiome in human health.
In a more recent study with collaborators from University of California San Diego and University of Southern California, we found that adding corn syrup to infant formula can enhance the populations of beneficial microbes they might otherwise have gotten from breast milk.
We hope this is the first of many studies we work on with this team, because the transition of infants from breast milk or formula to conventional foods is thought to be the most drastic example of how the microbiome changes with diet. Studying infants and their diets at this early point in life could help reveal fundamental truths that we’ll be able to translate to other syndromes related to the microbiome in children and adults worldwide, regardless of food security.
And this isn’t just speculation. Another study with the team in St. Louis used the same methods as the malnutrition study to develop supplementary foods, called “fiber snacks,” to correct microbiome imbalances in people with obesity. One might think that obesity would be the total opposite of malnutrition, but the microbiome is a key player in both.
More broadly, gut microbes are already the most well-studied part of the human microbiome, and the list of health associations with these microbes extend well beyond the digestive tract, even into the immune system, affecting the risk for diseases like cancer or diabetes. There’s also a growing body of evidence that suggests that gut microbes can have a direct effect on the brain. For example, the microbiome is being studied closely in connection to autism spectrum disorder, since many people on the spectrum experience concurrent gastrointestinal syndromes.
What would you say is important to know for people not familiar with the subject?
We need to acknowledge that our body and many of its problems have a huge microbiome component. The human body is a complex organism, and we are still learning how the microbiome influences and is influenced by different health conditions. The next step is to incorporate the role of the microbiome into the design of new diagnostics and therapeutics—because this undoubtedly influences their effectiveness. We can’t ignore this aspect of our biology, and the time is ripe to improve our understanding of it and leverage it to our advantage. Moving forward, this is going to help us solve so many problems—from issues we’ve already started looking at like obesity and malnutrition, all the way through to problems we aren’t even aware of yet.
What are the next steps for you and your team?
What we’re really interested in now is exploring new genomic technologies that are starting to revolutionize the field. The latest development is something called MAG genomics, short for metagenomically assembled genomes. This involves looking at the big picture, sequencing DNA from the whole microbiome at once in a way that is much faster and of much better quality than we’ve ever been capable of before. It’s like the difference between watching a movie on a clunky pixelated monitor from the 80’s and seeing that same movie on an HD monitor. Methods like this are moving us into a new paradigm in biomedical research, one that may be more complex, but also one that has the potential to substantially improve health outcomes for people around the world.