Prematurity Linked to Altered Lung Function During Exercise, High Blood Pressure in Adults

Released: 24-Apr-2014 11:00 AM EDT
Embargo expired: 29-Apr-2014 3:45 PM EDT
Source Newsroom: Federation of American Societies for Experimental Biology (FASEB)
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Citations Experimental Biology, April-2014

Newswise — San Diego, CA (April 29, 2014) — Advances in medicine have greatly contributed to the survival of extremely preterm infants in the US. However, the picture of long-term health effects related to prematurity is still unclear. Researchers at the University of Oregon compared lung function among adults who were born extremely preterm (at less than 28 weeks), very preterm (at less than 32 weeks), and full term (~39–40 weeks). Steven Laurie, PhD, will present the research team’s findings in a poster session on Tuesday, April 29, at the Experimental Biology meeting (San Diego Convention Center from 12:45–3:00 PM PST).

Laurie et al. studied three groups at rest and during exercise: young adults who were born extremely to very preterm and developed a lung condition called bronchopulmonary dysplasia (BPD), preterm adults who didn’t develop BPD (PRE), and full-term adult control subjects (CONT). They found that the PRE subjects had a harder time handling the increased blood flow from the heart during exercise than the BPD and CONT subjects. The vascular function of the lungs during exercise suggested that the PRE adults may also be at increased risk of developing high lung blood pressure.

From the researchers: “Healthy young humans have lungs designed to easily handle the increased blood flow from the heart during exercise. However, adults born extremely to very preterm have abnormally developed lungs, which may result in lungs that are unable to handle the demands of exercise. Surprisingly, the BPD subjects appear to have lungs that exhibit a normal response and accommodate the increased blood flow during exercise, suggesting a protective role of the oxygen treatments they received as infants. However, PRE subjects who did not receive the same level of oxygen treatment during their first few weeks of life appear to develop elevated blood pressure in their lungs during exercise as adults.”

Full Abstract
Augmented pulmonary artery pressure response during exercise in adults born extremely preterm but not in those with bronchopulmonary dysplasia

Advances in perinatal care in the post surfactant era have increased survivability of infants born extremely preterm <32 weeks gestation) yet long-term cardiopulmonary consequences of prematurity in adulthood remain largely unexplored. We studied adults who developed new bronchopulmonary dysplasia (BPD 22.7 yrs) preterm subjects who did not develop BPD (PRE 21.1 yrs) and fullterm controls (CONT 22.7 yrs) at rest and during cycle ergometer exercise in the forward leaning aerobar position. Subjects exercised for 3 min at 25% 50% and 75% of their maximum workload attained at VO2max from a separate visit. We measured metabolic rate and pulmonary artery systolic pressure (PASP) with ultrasonography at rest and during exercise. There were no differences in PASP between the groups at rest. At 50% and 75% VO2max PASP was higher in PRE subjects than in BPD and CONT subjects which were not significantly different from each other at any exercise intensity. The slope of the PASP to VO2 relationship was significantly greater in PRE subjects compared to BPD and CONT. These data suggest PRE subjects have a reduced ability for the pulmonary vasculature to accommodate increases in cardiac output during exercise compared to CONT and BPD subjects. Further research is needed to determine if this augmented pressure response during exercise may predispose PRE subjects to developing pulmonary arterial hypertension.

NOTE TO JOURNALISTS: To schedule an interview with a member of the research team, please contact Stacy Brooks at sbrooks@the-aps.org or (240) 432-9697.

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