209. The microvascular endothelial glycocalyx: impaired barrier function in preeclampsia with small gestational age neonates

Abstract

Introduction The glycocalyx, the endothelial lining of membrane-bound proteoglycans and glycoproteins, serves as a functional barrier between flowing red blood cells (RBC) and the endothelial cell membrane. Recent studies suggest that damage to the glycocalyx, which can be reflected by deeper radial penetration of RBC into the glycocalyx, contributes to microvascular dysfunction. Hypothesis We hypothesized that women with preeclampsia, especially those who deliver a small-for-gestational age neonate (PE + SGA, birthweight Methods We compared 30 women with a normotensive pregnancy (NP) to 30 women with preeclampsia (PE), matched for gestational age at time of analysis and presence/absence of labor. Using sidestream dark field imaging of the sublingual microcirculation, we measured 1) the accessibility of the RBC into the glycocalyx layer (perfused boundary region, PBR), defined as the difference between median and maximal RBC column widths, and 2) the microvascular density (total length of perfused microvessels/mm2 area). In healthy vessels, PBR is relatively small due to limited penetration of RBC into the glycocalyx. Results We observed no significant group differences in microvascular density (229 ± 75 mm/mm2 PE, 247 ± 88 mm/mm2 NP, P = 0.48) or PBR (2.20 ± 0.22 μm PE, 2.14 ± 0.30 μm NP, P = 0.14). However, the subset of women with PE + SGA (n = 12) evidenced a significant reduction in vascular density (205 ± 67 vs 306 ± 71 mm/mm2, P Discussion The increase in RBC encroachment (PBR) into the microvascular glycocalyx in PE + SGA compared to NP indicates a change in glycocalyx structure which may be associated with a reduced vascular protective function of the glycocalyx, possibly contributing to endothelial and microvascular dysfunction. Funded by NIH-NICHD (P01 HD030367, R21 HD083659), and AHA16SFRN27870000.