Increased urinary albumin leakage is related to injuries of glomerular glycocalyx and podocytes, and associated with tubular dysfunction in preeclampsia

Abstract

Objective: The pathogenesis of preeclampsia (PE) is known to be endothelial cell damage; however, the existence of dysfunction in glomerular endothelial glycocalyx, podocytes and tubules remains unclear. The glomerular endothelial glycocalyx, basement membrane, podocytes, and tubules are permeability barriers against albumin excretion. This study aimed to assess the relationship between urinary albumin leakage and injuries of the glomerular endothelial glycocalyx, podocytes, and tubules in patients with PE.

Methods: A total of 81 women with uncomplicated pregnancies (control, n = 22), PE (PE, n = 36), or gestational hypertension (GH) (GH, n = 23) were enrolled. We assessed urinary albumin and serum hyaluronan for glycocalyx injuries, podocalyxin for podocytes injuries, and urinary N-acetyl-β-d-glucosaminidase (NAG) and liver-type fatty acid-binding protein (l-FABP) for renal tubular dysfunctions.

Results: The serum hyaluronan and the urinary podocalyxin levels were higher in the PE and GH groups. The urinary NAG and l-FABP levels were higher in the PE group. Urinary NAG and l-FABP levels positively correlated with urinary albumin excretion.

Conclusions: Our findings suggest that increased urinary albumin leakage is related to injuries of the glycocalyx and podocytes, and associated with tubular dysfunction in pregnant women with PE. The clinical trial described in this paper was registered at the UMIN Clinical Trials Registry under registration number UMIN000047875. URL of registration: https://centre6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000054437.

Keywords: Glycocalyx; Liver-type fatty acid-binding protein; N-acetyl-β-d-glucosaminidase; Podocyte; Preeclampsia; Urinary albumin.