253. Sublingual microvascular density and glycocalyx barrier dynamics, during and after normal and preeclamptic pregnancy

Abstract

Introduction The apical surface of the vascular endothelium comprises a complex meshwork of membrane-bound proteoglycans and glycoproteins, the glycocalyx. The glycocalyx has important vasoregulatory roles; e.g., growth factor binding, signal transduction, coagulation and permeability. Glycocalyx damage has been implicated in several vascular diseases. Hypothesis Glycocalyx structural barrier integrity and microvascular perfusion are reduced in women with preeclampsia (PE). Methods We evaluated 17 women with PE and 27 with uncomplicated pregnancy (NL), just prior to delivery (LD) and at 24–48 h postpartum (PP). The sublingual microvasculature was interrogated using sidestream-darkfield imaging to compare glycocalyx integrity, microvascular density and percentage of perfused vascular segments. Glycocalyx integrity (for vessels 5–25 μm) was measured as depth of the RBC accessible region(AR), in which greater AR signifies diminished ability of glycocalyx to exclude RBCs. Plasma soluble syndecan-1, a shed glycocalyx component, was measured by ELISA. Results Microvascular density (segments/mm2) was greater in NL-LD (478 ± 28) compared to PE-LD (378 ± 35 p = 0.002), decreasing in both NL-PP (355 ± 28) and PE-PP (306 ± 35). Perfusion was not different between groups. AR in NL-LD (2.33 ± 0.05microns) was surprisingly greater than PE-LD (2.17 ± 0.06 p = 0.03), or NL-PP (2.19 ± 0.05 p = 0.05) but not different from PE-PP (2.26 ± 0.06). The change in AR between timepoints (LD-PP) indicates postpartum improvement in barrier function in NL (but not PE) group (−0.09 ± 0.4 vs 0.08 ± 0.3 p = 0.05). Maternal plasma syndecan-1 was higher in NL-LD (1126 ± 110.3 ng/mL) compared to PE-LD (715.5 ± 112.1 ng/mL; p = 0.008), and declined in both groups PP (NL-PP 210 ± 98, PE-PP 173 ± 120; NS). Conclusion Women with PE exhibited a reduction in functional microvascular density compared to NL. The increase in RBC accessibility(AR) in NL compared to PE was opposite to our hypothesis. This reduction in endothelial glycocalyx barrier function was accompanied by a higher level of circulating syndecan-1 prior to delivery in NL. The physiologic significance of these glycocalyx changes remain to be determined. Funding PO1-HD-30367, R21-HD-83659, AHA16SFRN27810001