Nature of glomerular dysfunction in pre-eclampsia

Background. Pre-eclampsia is characterized by hypertension, proteinuria and edema. Simultaneous studies of kidney function and structure have not been repel-red. We wished to explore the degree and nature of glomerular dysfunction in pre-eclampsia. Methods. Physiologic techniques were used to estimate glomerular filtration rate (GFR, renal plasma flow and afferent oncotic pressure immediately after delivery in consecutive patients with pre-eclampsia (PET; N = 13). Healthy mothers completing an uncomplicated pregnancy served as functional controls (N = 12). A morphometric analysis of glomeruli obtained bl biopsy and mathematical modeling were used to estimate the glomerular ultrafiltration coefficient (K-f). Glomeruli from healthy female kidney transplant donors sen ed as structural controls ((N = 8). Results. The GFR in PET was depressed below the control level, 91 +/- 23 versus 149 +/- 34 ml/min/1.73 m(2), respectively (P < 0.0001). In contrast. renal plasma flow and oncotic pressure were similar in the two groups (P = NS). A reduction in thr density and size of endothelial fenestrae and subendothelial accumulation of fibrinoid deposits lowered glomerular hydraulic permeability in PET compared to controls. 1.81 Versus 2.58 x 10(-9) m/sec/PA. Mesangial cell interposition also curtailed effective filtration surface area. Together. these changes lowered the computed single: nephron It, in PET below control. 4.26 versus 6.78 nl/min . mm Hg. respectively. Conclusion. The proportionate (similar to 40%) depression of K-f for single nephrons and GFR suggests that hypofiltration in PET does not have a hemodynamic basis, but is a consequence of structural changes that lead to impairment of intrinsic glomerular ultrafiltration capacity.