Posts tagged SIDS

Research at the University of Adelaide has shed new light onto the possible causes of sudden infant death syndrome (SIDS), which could help to prevent future loss of children’s lives.

In a world-first study, researchers in the University’s School of Medical Sciences have found that telltale signs in the brains of babies that have died of SIDS are remarkably similar to those of children who died of accidental asphyxiation.

"This is a very important result. It helps to show that asphyxia rather than infection or trauma is more likely to be involved in SIDS deaths," says the leader of the project, Professor Roger Byard AO, Marks Professor of Pathology at the University of Adelaide and Senior Specialist Forensic Pathologist with Forensic Science SA.

The study compared 176 children who died from head trauma, infection, drowning, asphyxia and SIDS.

Researchers were looking at the presence and distribution of a protein called β-amyloid precursor protein (APP) in the brain. This “APP staining”, as it’s known, could be an important tool for showing how children have died. This is the first time a detailed study of APP has been undertaken in SIDS cases.

"All 48 of the SIDS deaths we looked at showed APP staining in the brain," Professor Byard says.

"The staining by itself does not necessarily tell us the cause of death, but it can help to clarify the mechanism.

"The really interesting point is that the pattern of APP staining in SIDS cases - both the amount and distribution of the staining - was very similar to those in children who had died from asphyxia."

Professor Byard says that in one case, the presence of APP staining in a baby who had died of SIDS led to the identification of a significant sleep breathing problem, or apnoea, in the deceased baby’s sibling.

"This raised the possibility of an inherited sleep apnoea problem, and this knowledge could be enough to help save a child’s life," Professor Byard says.

"Because of the remarkable similarity in SIDS and asphyxia cases, the question is now: is there an asphyxia-based mechanism of death in SIDS? We don’t know the answer to that yet, but it looks very promising."

This study was conducted at the University of Adelaide by visiting postdoctoral researcher Dr Lisbeth Jensen from Aarhus University Hospital, Denmark, and was funded by SIDS and Kids South Australia. The results have been published in the journal Neuropathology and Applied Neurobiology.

"This work also fits in very well with collaborative research that is currently being undertaken between the University of Adelaide and Harvard University, on chemical changes in parts of the brain that control breathing," Professor Byard says.

(Source: adelaide.edu.au)

When mice are born lacking the master gene Atoh1, none breathe well and all die in the newborn period. Why and how this occurs could provide new answers about sudden infant death syndrome (SIDS), but the solution has remained elusive until now.

Research led by Baylor College of Medicine and the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital demonstrates that when the gene is lacking in a special population of neurons called RTN (retrotrapezoid nucleus), roughly half the young mice die at birth. Those who survive are less likely to respond to excess levels of carbon dioxide as adults. A report of their work appears online in the journal Neuron.

"The death of mice at birth clued us in that Atoh1 must be needed for the function of some neurons critical for neonatal breathing, so we set out to define these neurons," said Dr. Huda Zoghbi, senior author of the report and director of the Neurological Research Institute and a professor of molecular and human genetics, neuroscience, neurology and pediatrics at BCM. Zoghbi is also a Howard Hughes Medical Institute investigator.

"We took a genetic approach to find the critical neurons," said Wei-Hsiang Huang, a graduate student in the Program in Developmental Biology at BCM who works in Zoghbi’s laboratory. With careful studies to "knockout" the activity of the gene in a narrower and narrower area in the brain, they slowly eliminated possible neurons to determine that loss of Atoh1 in the RTN neurons was the source of the problem.

"Discovering that Atoh1 is indeed critical for the RTN neurons to take their right place in the brainstem and connect with the breathing center helped us uncover why they are important for neonatal breathing," said Zoghbi.

"This population of neurons resides in the ventral brainstem," said Huang. "When there is a change in the makeup of the blood (lack of oxygen or buildup of carbon dioxide), the RTN neurons sense that and tell the body to change the way it breathes." A defect in these neurons can disrupt this response.

"Without Atoh1 the mice have significant breathing problems because they do not automatically adjust their breathing to decrease carbon dioxide and oxygenate the blood," he said.

It turns out the findings from this mouse study are relevant to human studies.

"A paper just published reports that developmental abnormalities in the RTN neurons of children with sudden infant death syndrome or sudden unexplained intrauterine death may be linked to altered ventilatory response to carbon dioxide", said Huang (Lavezzi, A.M., et al., Developmental alterations of the respiratory human retrotrapezoid nucleus in sudden unexplained fetal and infant death, Auton. Neurosci. (2012), doi:10.1016/j.autneu.2012.06.005).

(Source: bcm.edu)