New research sheds light on the molecular basis of crib death

Sudden Infant Death Syndrome (SIDS) is a condition that unexpectedly and unexplainably takes the lives of seemingly healthy babies aged between a month and a year.

Now researchers of the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, have developed a mouse model of the so-called crib or cot death, which remains the leading cause of death during the first year of life in developed countries. The model, published in this week’s issue of Science, reveals that an imbalance of the neuronal signal serotonin in the brainstem is sufficient to cause sudden death in mice.

The brainstem, the lower part of the brain that forms the link to the spinal cord, coordinates many fundamental functions including control over cardiovascular and respiratory systems. Victims of SIDS show alterations in those brainstem neurons that communicate using the signalling molecule serotonin. Cornelius Gross and his group at the EMBL Mouse Biology Unit modified the serotonin system of mice to understand the role of this signalling molecule in the brainstem. They overexpressed an important receptor that regulates serotonin signalling, called serotonin 1A autoreceptor.

“At first sight the mice were normal. But then they suffered sporadic and unpredictable drops in heart rate and body temperature. More than half of the mice eventually died of these crises during a restricted period of early life. It was at that point that we thought it might have something to do with SIDS,” says Gross.

Until now it was unclear how changes in serotonin signalling in the brainstem of SIDS infants are involved in sudden death. The findings in the mouse show that deficits in serotonin signalling in the brainstem can be sufficient to cause sudden death and strongly support the idea that a congenital serotonin defect could play a critical role in SIDS.

Serotonin neurons in the brainstem communicate to nerve cells in the spinal cord that innervate the heart and organs involved in temperature regulation such as brown fat tissue. This signalling is defective in the mouse model of SIDS. For example, when placed into a cold chamber the animals cannot properly activate brown fat tissue to produce heat. This inability to activate fundamental body systems under certain conditions is likely to explain why the mice succumb to sudden death.

While a complete block of serotonin signalling does not lead to death, upsetting its intricate balance by overexpressing serotonin 1A autoreceptor can. In response to serotonin the receptor initiates a negative feedback mechanism that reduces serotonin release and dampens down the signal to the body. The researchers caution, however, that it is unlikely that the exact same molecular mechanism leads to SIDS in humans. Nevertheless, the mouse model will help to shed light on how serotonin signalling, when dysfunctional, can be life-threatening.

“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. Ultimately, we hope it will give new ideas to doctors about how to diagnose babies at risk for SIDS,” says Enrica Audero, who carried out the research in Gross’ lab.

Media Contact

Anna-Lynn Wegener EMBL

More Information:

http://www.embl.de

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors