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Study sheds light on cot death factors

04/07/2008

Research published today could help to identify new risk factors for cot death, scientists claim.

Cot death, or sudden infant death syndrome (SIDS), is a condition that unexpectedly takes the lives of seemingly healthy babies aged between a month and a year.

Using a mouse model of SIDS, researchers at the European Molecular Biology Laboratory in Monterotondo, Italy, found that an imbalance of a molecule involved in signalling in the body - named serotonin - is sufficient to cause sudden death.

While the researchers say it is unlikely that the exact same molecular mechanism leads to SIDS in humans, they argue in the journal Science that the mouse model will help to shed light on how serotonin signalling, when not working how it should, can be life-threatening.

Serotonin neurons in the brainstem communicate to nerve cells in the spinal cord that stimulate the heart and organs involved in temperature regulation such as brown fat tissue.

In the study the scientists increased an important receptor that controls serotonin signalling, called serotonin 1A autoreceptor.

After appearing normal for a while the mice then suffered sporadic and unpredictable drops in heart rate and body temperature.

More than half the mice eventually died as a result.

Until now it was unclear how changes in serotonin signalling in the brainstem of SIDS infants are involved in sudden death, the researchers claim.

They add that the findings in mice show deficits in serotonin signalling in the brainstem can be sufficient to cause sudden death and strongly support the idea that a genetic serotonin defect could play a critical role in SIDS.

"We hope the mouse model will help identify risk factors for SIDS. One open question is whether like in SIDS, the animals die during sleep and whether we can identify which mice will die by looking at their heart rate or body temperature before the crisis," said researcher Enrica Audero.

"Ultimately, we hope it will give new ideas to doctors about how to diagnose babies at risk for SIDS."