title: Sex-specific differences in peripheral microvascular blood flow in preterm infants.
abstract: Microvascular blood flow is related to physiologic instability in newborn preterm infants. We investigated sex-specific differences in basal microvascular blood flow and the ability of the microvasculature to respond to vasoactive stimuli following preterm birth. Ninety-six infants in two gestational age groups (24-28 and 29-36 wk) were studied on days 1-5 of life. Laser Doppler flowmetry was used to measure baseline microvascular blood flow and vasodilatation in response to acetylcholine and local warming. A significant interaction of gestational age and sex was observed for baseline flow at 24 h of age. In the 24-28 wk group, male infants had higher baseline flow than females. Male, but not female, infants born at 24-28 wk exhibited a significant relationship between baseline flow and vasodilatory response to acetylcholine at 24 h of age. By 120 h of age, both sexes exhibited similar responses. Infants born at 24-28 wk exhibited greater vasodilatation in response to local warming than those born at 29-36 wk at 24, 72, and 120 h of age. Sex-specific differences in microvascular blood flow and vasodilatory capacity in the immediate newborn period may affect the transitional circulation, contributing to excess of morbidity and mortality in preterm males.
authors: Mother and Babies Research Centre, University of Newcastle, Newcastle, NSW 2305, Australia.
authors: Michal J
authors: MJ
authors: Stark
authors: Vicki L
authors: VL
authors: Clifton
authors: Ian M R
authors: IM
authors: Wright
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging / Q000502:physiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012727:Sex Characteristics; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D000109:Acetylcholine