Study: Sudden Infant Death Syndrome Linked to Brain Chemical in Mice

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Cornelius Gross, a researcher at the Monterotondo, Italy-based European Molecular Biology Laboratory and co-author of the study, genetically modified the mice to produce low levels of the brain-signaling protein serotonin. As a result, the mice suffered drops in heart rate and showed signs of SIDS, and many died at an early age. Serotonin controls heartbeat and breathing, and depleted levels lead to early deaths.

Gross and his team hope to identify the serotonin imbalances early on and prevent crib deaths. By measuring serotonin levels, the babies can be given proper care.

William Fifer, professor of psychiatry and pediatrics at Columbia who advised the study's authors told Bloomberg:

This is one more significant source of information that shows that serotonin deficiency may be the key in SIDS…Research in this area has been painstakingly slow.

Previously, the parents were warned to monitor their babies regularly and to avoid exposure to smoke, cluttered cribs or tummy sleeping, which may cause SIDS. The public awareness helped reduce SIDS deaths in babies from as high as 6,000 in the 1980s, but still the doctors had no clear answer as to what caused this deadly disease.

Two years ago scientists at Children’s Hospital Boston and Harvard Medical School performed autopsies on 31 SIDS babies and found they had abnormal levels of serotonin in their brains.

Serotonin acts as a chemical messenger in the brain that transmits signals between nerve cells. Among its many effects, the chemical helps regulate sleep, appetite and mood, as well as body temperature and breathing rates during periods of excitement.

In this mice study, the researchers genetically modified the mice to create a serotonin imbalance in their brains. Then they introduced the mice to slight external temperature changes; they died because they couldn’t cope with it. Cornelius Gross told Bloomberg:

The serotonin system can be lethal if it's not regulated in some way.

The babies that have the serotonin imbalance and when they sleep on their stomach are prevented from reacting to changes, so they breathe their own exhaled carbon dioxide, leading to their death due to SIDS. Normal healthy babies just roll over and breathe fresh oxygen.

It is a great start by the Italian researchers and hopefully scientists will eliminate SIDS in the near future.