Discovery Leads to Clue in SIDS Deaths

By Anastacia Mott Austin

An accidental discovery by scientists studying serotonin in mice may help lead researchers to answers about Sudden Infant Death Syndrome (SIDS) in humans.

Researchers at Italy’s European Molecular Biology Laboratory were examining connections between serotonin levels and anxiety and aggression in lab mice.

What they discovered was that many of the gene-altered mice, whose serotonin regulating systems were faulty, died suddenly.

Not only that, but changes in heart rate and body temperature just prior to the deaths had similarities to what is believed happens to human infants who die of SIDS.

The results of the study is published in the July 4th issue of Science journal.

The neurotransmitter serotonin is involved with temperature and heart rate regulation, and problems with these two body functions are known to be risk factors in SIDS.

Experts have known for a while that heart rate fluctuations are involved in SIDS risk, and stomach sleeping for babies is known to create greater heart rate changes. The successful campaign to put babies on their backs to sleep has reportedly lowered deaths from SIDS.

Another risk factor, temperature regulation, has been mitigated by parents’ being warned to not overbundle their babies before sleeping, so they don’t get too warm.

Other common sense advice to avoid smoking around babies and make sure pillows and heavy blankets are not placed in cribs have helped make sure infants don’t get exposed to too much carbon dioxide while sleeping, or suffocate on soft bedding.

SIDS rates have steadily decreased since the success of these campaigns, but 2,000 infants still die each year of the bewildering disease. Infants who die of SIDS can appear to be perfectly healthy just hours before their deaths.

The serotonin regulation link can be added to the arsenal of information experts need to help prevent SIDS.

"This mouse model is important," said SIDS expert Marian Willinger, from the National Institute of Child Health and Human Development, to reporters at a press conference. "Causing dysfunction in brainstem serotonin can lead to death in a majority of affected animals."

The study’s results won’t provide any concrete solutions, but rather an additional clue to the puzzle about the disorder.

Added Dr. Rachel Moon, a SIDS expert from the Children’s National Medical Center, "Some babies are more at risk, and these environmental factors could overwhelm the baby's capabilities." Dr. Moon said that for these at-risk infants, lifesaving modifications (like an alarm system that notifies parents when a baby stops breathing) could be made. "If you could identify which babies are at risk, you could be a little more specific in who you insist make behavioral changes and modifications."