New research on what happens as a newborn is delivered and takes its first breath may shed light on a potential contributor to sudden infant death syndrome (SIDS).
A team led by doctors from the University of Virginia School of Medicine discovered a signaling system within the brainstem that activates almost immediately at birth to support early breathing.
The findings help researchers understand how breathing transitions from its initially fragile state to a stable and robust physiological system that supplies the body with oxygen throughout a lifetime. Before birth, breathing is not required, so the transition at birth is a highly vulnerable time.
"Birth is traumatic for the newborn, as the baby has to independently take control over various important body functions, including breathing," explained Douglas Bayliss, chairman of the university's department of pharmacology. "We think that activation of this support system at birth provides an extra safety factor for this critical period."
In this signaling system in mice, a specific gene is turned on immediately at birth in a cluster of neurons that regulate breathing selectively, according to the researchers. The gene produces what's called a peptide neurotransmitter, a chain of amino acids that sends messages between neurons. The transmitter, called PACAP, starts to be released by the neurons just as the newborn emerges into the world.
In the study in mice, suppressing the peptide led to breathing problems and dangerous pauses in breathing, which suggests that the neuropeptide system may contribute to SIDS, the study authors said. But research in animals doesn't always pan out in humans.
The leading cause of infant mortality in Western countries, SIDS is the sudden and unexplained death of a child less than 1 year old. It is attributed to a combination of genetic and environmental factors, including temperature.
The new research, published Dec. 2 in the journal Nature, suggests that problems with the neuropeptide system may increase babies' susceptibility to SIDS and other breathing problems.
PACAP is the first signaling molecule shown to be massively and specifically turned on at birth by the breathing network, and it has been linked genetically to SIDS in babies. The causes of SIDS likely are complex, and there may be other important factors to discover, the researchers noted.
"These findings raise the interesting possibility that additional birth-related changes may occur in the control systems for breathing and other critical functions," Bayliss said in a university news release. "We wonder if this could be a general design principle in which fail-safe support systems are activated at this key transition period, and that understanding those may help us better treat disorders of the newborn."
The U.S. Centers for Disease Control and Prevention has more about SIDS.
SOURCE: University of Virginia Health System, news release, Dec. 4, 2020