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BIDDEFORD, Maine

JAMA publishes research on link between SIDS and serotonin conducted by team that includes UNE Professor David Mokler

In a collaboration with researchers at Children's Hospital Boston, University of New England Professor of Pharmacology David Mokler, Ph.D., has played a key role in research that has linked sudden infant death syndrome (SIDS) with low production of serotonin in the brainstem.  

The findings, published in the Feb. 3, 2010 issue of The Journal of the American Medical Association, may give a concrete approach to identifying babies at risk for SIDS, the leading cause of death for infants between 1 and 12 months old in the United States. 

Dr. Mokler, a professor in UNE's College of Osteopathic Medicine, is a contributing author to the paper.  UNE graduate Jill Hoffman, College of Arts and Sciences class of 2003, is also a contributing author.

SIDS and the Brainstem

SIDS has been linked to the area of the brain called the brainstem.  In the brainstem, serotonin helps to regulate some of the body's involuntary actions, such as breathing, heart rate and blood pressure during sleep. The researchers believe that a low serotonin level impairs the function of the brainstem circuits that regulate these activities, putting a baby at risk for sudden death from stresses such as rebreathing carbon dioxide when sleeping in the face-down position.

Dr.  Mokler, who conducts research at the UNE Center for Excellence in the Neurosciences on the Biddeford Campus, is well-known for his research on the serotonin systems of the brain.  This research study involved a comparison of brainstem samples from infants dying of SIDS compared to brainstems of infants dying from other, known causes.  

Dr. Mokler developed a protocol that measures the level of serotonin in the brainstem tissue in the babies who died of SIDS.  Tissue samples from the brainstem were obtained from autopsies and provided by research partners at the San Diego County Medical Examiner's Office in California.

The Results

The results showed that compared with controls, the serotonin levels in the lower brainstem were 26 percent lower in the SIDS cases compared to controls, while the tryptophan hydroxylase (the enzyme that helps make serotonin) levels were 22 percent lower. 

Levels of binding to serotonin receptors were also lower by more than 50 percent. The consistency and correlation of these findings with each other reinforce the idea that SIDS in the majority of cases is a disorder of serotonin in the brainstem, the researchers say.

The future goal of this work is to devise a test to identify infants with a serotonin brainstem defect early, and to develop preventive treatments that would correct the serotonin deficiency.

Dr. Mokler states, "This research greatly advances our understanding of this devastating syndrome.  This paper verifies and extends these serotonin deficiencies in the brain; from here, the research will move to other areas, such as investigating a possible genetic link to unusually low serotonin levels."

Other Risk Factors

While this study provides strong evidence for a biological cause of SIDS, it also shows that other risk factors, such as the baby sleeping on its stomach, alcohol consumption by the mother during pregnancy, and exposure to smoking, can increase the risk. Of the SIDS infants in the current study, 95 percent died with at least one risk factor, and 88 percent died with at least two.

Media Coverage

The research, when it was published on Feb. 3rd, was covered by more than 60 TV, print and online media outlets around the world, such as The New York Times, The Today Show on NBC, Good Morning America on ABC, CNN, USA Today, the Los Angeles Times, the Boston Globe, The Washington Post, Sydney Morning Herald, London Telegraph, Reuters, Business Week and Science Daily, to name a few.

This study was supported by funds from the First Candle/SIDS Alliance, CJ Martin Overseas Fellowship, the CJ Murphy Foundation, the National Institute of Child Health and Development, and the Developmental Disabilities Research Center at Children's Hospital Boston.

Citation: Jhodie R. Duncan, PhD, David S. Paterson, PhD, Jill M. Hoffman, BS, David J. Mokler, PhD, Natalia S. Borenstein, MS, Richard A. Belliveau, BA, Henry F. Krous, MD, Elisabeth A. Haas, BA, Christina Stanley, MD, Eugene E. Nattie, MD, Felicia L. Trachtenberg, PhD, Hannah C. Kinney, MD. Brainstem serotonergic deficiency in Sudden Infant Death Syndrome. JAMA Feb. 3, 2010, Vol. 303, No. 5.

About the University of New England

The University of New England is Maine’s largest independent university, with two beautiful coastal campuses in Maine, a one-of-a-kind study abroad campus in Tangier, Morocco, and an array of flexible, accredited online degrees. In an uncommonly welcoming and supportive community, we offer hands-on learning, empowering students to make a positive impact in a world full of challenges. The state’s top provider of health professionals, we are home to Maine’s only medical college, Maine’s only dental college, a variety of other interprofessionally aligned health care degree programs, as well as nationally recognized programs for marine science degrees, natural and social sciences degrees, arts and humanities degrees, and business degrees.