Human breast milk has long been considered “liquid gold” among doctors treating premature babies in a neonatal intensive care unit (NICU). Breastfed “premature babies” are, on average, healthier than formula-fed babies. However, why that is true remains a mystery.
Newswise — New research from the Institute for Genome Sciences (IGS) at the University of Maryland School of Medicine (UMSOM), published online in mBio magazine in June found that it’s not just the content of breast milk that makes the difference. It’s also how babies digest it.
The investigation, led by Bing Ma, Ph.D., Assistant Professor of Microbiology and Immunology at UMSOM and an IGS researcher, discovered a strain of the bacterium Bifidobacterium breve, or B. breve, in the intestines of breastfed infants who received larger volumes of breast milk than their counterparts. Those premature babies absorbed nutrients better because they developed an intact intestinal wall a week after birth. B. breve was much less common in both formula-fed and breastfed babies with “leaky gut.” Babies with leaky gut do not develop a barrier to protect against bacteria and digested food from entering the bloodstream. For the first time, the team also found that the way B. breve metabolizes breast milk keeps breastfed babies healthier and allows them to gain weight by strengthening their underdeveloped intestinal barrier.
An immature or “leaky” gut can lead to necrotizing enterocolitis (NEC), which is the third leading cause of death for newborns in the United States and worldwide. In fact, NEC affects up to 10 percent of premature babies with a devastating mortality rate of up to 50 percent.
“Our discovery could lead to promising and practical clinical interventions to strengthen the gut of infants and thereby increase survival rates for the most vulnerable preterm infants,” said Dr. Ma.
Bifidobacteria in the gut or microbiome have long been known to have health benefits. It includes a diverse set of strains that have very different properties. Some strains are only found in adults; some are mostly in their teens. One strain, Bifidobacterium infantis, has been observed predominantly in term infants.
The researchers followed 113 premature babies who were born between 24 and 32 weeks of gestation. This study found Bifidobacterium breve (B. breve) only in premature infants who had improved intestinal barrier function within a week after birth. Dr. Ma and her colleagues discovered that Bifidobacterium breve is genetically equipped to digest nutrients within the cell membrane rather than the more typical external digestion process in which bacteria secrete digestive enzymes onto nutrients to break them down.
At the most basic level, the gut microbiome in these preemies breastfed with more B. breve metabolizes carbohydrates differently than it does with formula. The researchers say they hypothesize that this metabolism process then strengthens and matures the intestinal barrier faster, protecting fragile newborns from disease.
“We now know that it is not just breast milk that helps premature babies develop their intestinal barrier faster,” said Dr. Ma. “We will need to find the best way to prophylactically administer B. breve early in life. life, rather than relying on the transmission of breast milk or even the mother’s gut or vaginal microbiota during the birthing process. This is especially critical in formula-fed premature babies.”
Dr. Ma said more studies are needed to determine whether B. breve originated in breast milk, the intestine, the mother’s vagina, or even the environment.
E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs at the University of Maryland, Baltimore, the John Z. and Akiko K. Bowers Distinguished Professor and Dean of UMSOM said, “This research can have far-reaching impact globally. Ultimately, it could save thousands of premature babies from permanent disability or death associated with an immature, leaky gut that allows deadly bacteria to enter.”
Authors from the Genome Sciences Institute include Dr. Ma; Michael France, PhD, postdoctoral fellow; Elias McComb, BS, Research Technician; Lindsay Rutt, MS, Laboratory Research Manager; Pawal Gajer, PhD, Research Associate, Microbiology and Immunology; Li Fu, BS, laboratory research specialist; Hongqiu Yang, PhD, Microbiome Service Laboratory; Mike Humphrys, MS, Director of the Microbiome Services Laboratory; Luke J. Tallon, BA, Executive Scientific Director, Maryland Genomics; Lisa Sadzewicz, PhD, Executive Director, Maryland Genomics Administration; Y Dr Jacques RavelProfessor of Microbiology and Immunology, Associate Director, Genomics and Acting Director, IGS.
Authors from other departments within the University of Maryland School of Medicine include Sripriya Sundararajan, MBBS, MD, Associate Professor of Pediatrics and Neonatal Director of OB-MFM Relations; Gita Nadimpalli, MD, PhD, MPH, graduate research assistant; Jose M. Lemme-Dumit, PhD, Post-Doc Fellow, Pediatrics; Elise Janofsky, Pediatrics; Lisa S. Roskes, MD, Pediatrics; Dr. Marcela F. Pasetti, Professor of Pediatrics, Microbiology and Immunology; Y Dr. Rose M. ViscardiEmeritus Professor of Pediatrics and Medicine.
This study was supported in part by a 2018 Gerber Foundation award (project identifier 6361), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health (grant number R21DK123674), and the Institute of Clinical and Translational Research (ICTR) at the University of Maryland Accelerated Translational Incubator Pilot (ATIP) Award.
The authors have no conflict of interest.
About the University of Maryland School of Medicine
Now in its third century, the University of Maryland School of Medicine was chartered in 1807 as the first public medical school in the United States. It continues today as one of the world’s fastest-growing, premier biomedical research companies, with 46 academic departments, centers, institutes, and programs, and a faculty of more than 3,000 physicians, scientists, and allied health professionals. including members of the National Academy of Medicine and the National Academy of Sciences, and a two-time distinguished recipient of the Albert E. Lasker Award for Medical Research. With an operating budget of more than $1.3 billion, the School of Medicine works closely with the University of Maryland Medical Center and Medical System to provide research-intensive academic and clinical care for nearly 2 million patients each year. . The School of Medicine has nearly $600 million in extramural funding, with most of its academic departments ranking highly among all medical schools in the country for research funding. As one of seven professional schools that make up the campus of the University of Maryland, Baltimore, the School of Medicine has a total population of nearly 9,000 faculty and staff, including 2,500 students, trainees, residents, and fellows. The combined Medical School and Medical System (“Maryland University of Medicine”) has an annual budget of more than $6 billion and an economic impact of nearly $20 billion on the state and local community. Ranked eighth among public medical schools for research productivity (as profiled by the Association of American Medical Colleges), the School of Medicine is an innovator in translational medicine, with 606 active patents and 52 start-ups. In the latest US News & World Report ranking of the best medical schools, published in 2021, the UM School of Medicine is ranked No. 9 out of 92 public medical schools in the US, and in the Top 15 percent (#27) of all 192 public and private US medical schools. The School of Medicine works locally, nationally, and globally, with research and treatment facilities in 36 countries around the world. Visit medschool.umaryland.edu
About the Genome Sciences Institute: the Institute of Genome Sciences (IGS) at the University of Maryland School of Medicine has revolutionized genomic discovery in medicine, agriculture, environmental science and biodefense since its founding in 2007. IGS researchers investigate areas of genomics and the microbiome to better understand health and disease, including treatments, cures, and prevention. IGS researchers are also leading the development of the new field of microbial forensics. IGS is a leading center for major biological initiatives currently underway, including the NIH-funded project Human Microbiome Project (HMP) and the one sponsored by the NIAID Center for Genomic Sequencing of Infectious Diseases (GSCID). Follow us on Twitter @GenomeScience.