Abstract 134: The Effect of Low Birth Weight on the Microcirculation in the 1 St Year of Life

Introduction: Capillary rarefaction, defined as a reduction in capillary density, is an established hallmark of essential hypertension. Low birth weight (LBW) infants, known to have an increased risk of developing hypertension as adults, were unexpectedly found to have a significantly higher capillary density at birth when compared to normal birth weight (NBW) infants. We therefore hypothesised that there is a microcirculatory window in the 1st year of life of LBW infants, during which a process of extensive capillary loss, known as “hyperpruning”, occurs. Methods: The George’s Capillary Rarefaction Offspring Study (G-CROS) is a longitudinal, multi-centre study of which 284 infants were NBW, born at term, and 77 were LBW. Intravital microscopy was used to measure the functional (also known as basal) capillary density (BCD), and the structural (also known as maximal) capillary density (MCD) at birth, 3 months, 6 months and 12 months. Results: LBW infants had a significantly higher capillary density at birt...