;Resize=(1200,627)&impolicy=perceptual&quality=mediumHigh&hash=cbe9a31fdf809243761830aefdd0129449523e65984e78b751f06c97e0569d37 "Sudden infant death: Researchers find possible cause")
Scientists may have found a biological cause for cot death – a previously unexplained death of some infants in their first year of life.
The researchers found that many of these children have an abnormality in a serotonin receptor in the brainstem. This docking site is considered an important part of breath control and an emergency response designed to prevent nocturnal oxygen deprivation and suffocation. In addition to risk factors such as babies lying on their stomachs, this anomaly could promote infant death.
Sudden infant death syndrome hits infants under the age of one year seemingly out of nowhere: the children die in their sleep without any previous illness or other recognizable cause. In Germany, around 100 children are affected each year, compared to around 1,000 in the past. The cause of infant death syndrome is unclear. However, we now know that the position of the infant in the cot can play an important role: sleeping on the stomach increases the risk.
Search for clues in the brainstem
Studies also suggest that sudden infant death syndrome could be related to a failure of breathing control: if a sleeping person does not get enough oxygen, an “emergency mechanism” in the brain stem is normally activated. This triggers particularly deep breaths and wakes up the sleeper. However, it is unclear why this “alarm” apparently fails in some infants, causing them to suffocate in their sleep. However, there are initial indications that the affected children have a deficiency of the hormone serotonin in the brainstem.
Robin Hayes from Harvard Medical School in Boston and his colleagues may have discovered a new lead. For their study, they analyzed brainstem tissue samples from 70 children who had died of sudden brain death in the area around San Diego, California. Samples from infants with other causes of death served as comparison material. The researchers looked for anomalies in the cells and their docking sites that could explain the lack of breath control.
Abnormality in a serotonin docking site
In fact, they found what they were looking for: Compared to the control samples, the infant death victims showed subtle changes in a special serotonin receptor. This docking site, known as 5-HT2A/C, showed abnormalities in 58 of the 70 infant death victims, while this only occurred in twelve cases in the comparison group. As a result of these changes, the serotonin can only be bound to a reduced extent, as Hayes and his team explain.
According to the research team, this receptor abnormality could be one of the reasons why some infants fail to control their breathing. “In rodents, activation of the 5-HT2A/C receptor contributes to wakefulness and respiratory control, and this protects the brain from oxygen starvation during sleep,” the scientists explain. If the receptor is not formed correctly, this protective mechanism could be weakened or even fail.
Three trigger factors for infant death
Accordingly, the sudden infant death could be due to a combination of three factors, as the team explains. The first: Infants go through a critical phase of their cardiorespiratory development in their first year of life, the system of respiratory control only matures in this phase. The second factor is external influences such as sleeping on your stomach, which can cause insufficient blood and oxygen supply. The third factor is the newly discovered biological abnormality in the brainstem that inhibits breath control and the “alarm” mechanism.
How exactly the receptor anomaly is linked to breathing control in infants and whether it can actually be the trigger for sudden infant death must now be clarified by further studies. This will be made more difficult by the fact that the subtle anomalies in the serotonin docking sites in the brainstem have so far only been detectable in tissue samples. “Right now, we don’t have a way to detect children with such biological abnormalities in the serotonin system,” says Hayes.
Prevention is key
The team emphasizes that it is therefore all the more important for parents to follow the recommendations for sleeping position and bedding for babies. This includes letting babies sleep on their backs and avoiding prone or side positions. In addition, there should be no pillows, skins or cuddly toys in the child’s head area. A sleeping bag instead of a blanket is also a possible protective measure. (Journal of Neuropathology & Experimental Neurology, 2023; doi: 10.1093/jnen/nlad030)
Quelle: Oxford University Press USA
Von Nadja Podbregar