When babies are born too early, they run the risk of developing problems in the lungs, brain, kidneys and more. Now, from the University of Washington, scientists found that heart function later in life is also a concern for preterm babies.
Preterm birth is normally defined as a baby born before 37 weeks of pregnancy have been completed, according to the Centers for Disease Control and Prevention. Around two percent of all births in the United States are preterm.
In the present study, scientists found that inflammatory reactions that accompany an infection prevent normal heart development, which relies of specific gene activity. This complication may not be evident during infancy or childhood, but researchers believe the consequences to come to fruition in adulthood.
"This study is the first to show that the gene program for heart development in preterm babies is interrupted in preterm babies exposed to fetal infection and inflammation, which may lead to incomplete heart development," explained co-study leader Timothy Mitchell. "This incomplete development, in turn, may be lead to the higher risk of abnormal heart rhythms and heart failure seen when preterm babies reach adulthood."
Mitchell and other researchers made the connection between preterm birth and heart disease later in life by investigating certain gene networks. Activity in these networks is interrupted by inflammatory protein levels that spike during fetal infection.
In their study, the researchers used a preterm birth animal model believed to be one of the closest to human pregnancy: heart tissue from pigtail macaque monkeys. Pregnant mothers were infected with bacteria that often cause infections in human mothers and lead to preterm birth.
Compared to heart tissue from healthy preterm monkeys, bacteria-infected tissue showed signs of altered gene expression. Three of the genes identified, NPPA, MYH6, ACE2, have been associated with heart disease and/or heart development in the past. Additionally, researchers saw evidence of altered gene network expression linked to heart and blood vessel formation.
"We are only beginning to understand the health risks that infection and inflammation pose to the developing fetus, particularly in the setting of an early preterm birth," explained co-study leader Lakshmi Rajagopal. "We need a better understanding of how bacteria invade the uterus to cause preterm birth so that we can develop therapies to prevent fetal infections.”
The present study was published in the journal American Journal of Obstetrics & Gynecology.