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Nature of glomerular dysfunction in pre-eclampsia

1998; Elsevier BV; Volume: 54; Issue: 4 Linguagem: Inglês

10.1046/j.1523-1755.1998.00097.x

1523-1755

Richard A. Lafayette, Maurice L. Druzin, Richard Sibley, Geraldine C. Derby, Tahira Y Malik, Phil Huie, Catherine Polhemus, William M. Deen, Bryan D. Myers,

Pregnancy and Medication Impact

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 reported. 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 by biopsy and mathematical modeling were used to estimate the glomerular ultrafiltration coefficient (K f ). Glomeruli from healthy female kidney transplant donors served as structural controls ( N = 8). Results The GFR in PET was depressed below the control level, 91 ± 23 versus 149 ± 34 ml/min/1.73m 2 , respectively ( P < 0.0001). In contrast, renal plasma flow and oncotic pressure were similar in the two groups ( P = NS). A reduction in the 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 × 10 -9 m/sec/PA. Mesangial cell interposition also curtailed effective filtration surface area. Together, these changes lowered the computed single nephron K f in PET below control, 4.26 versus 6.78 nl/min · mm Hg, respectively. Conclusion The proportionate (∼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.