Lysosomal enzymuria in preeclampsia.

We hypothesize that the preeclamptic patient has proximal tubule epithelial injury, which leads to the release of lysosomal enzymes, and that the excretion of these enzymes might serve as a diagnostic or predictive marker in preeclamptic women. The study group consisted of 14 women with preeclampsia (10 severe and 4 mild, as defined by The American College of Obstetricians and Gynecologists criteria) and 28 normotensive controls with singleton pregnancies at 27 to 41 weeks. There were no significant differences between the two groups for gestational age, maternal age, or race. Maternal serum and urine specimens were prospectively obtained and analyzed for beta-glucuronidase, beta-hexosaminidase, alpha-galactosidase, beta-galactosidase, and alpha-mannosidase using fluorometric assays. Median serum and urine activities and fractional excretions of each of the five hydrolases were compared between the two study groups using the Mann-Whitney two-sample rank test. The serum enzyme activities of beta-hexosaminidase (P = 0.002), alpha-galactosidase (P = 0.0001), and alpha-mannosidase (P = 0.02) were significantly lower in preeclamptic patients than in controls. The urine enzyme activities of beta-glucuronidase (P = 0.001), alpha-galactosidase (P = 0.002), beta-galactosidase (P 0.0003), and alpha-mannosidase (P = 0.003) were significantly higher in the preeclamptic patients. The fractional enzyme excretions of all five lysosomal hydrolases were higher in preeclamptic patients than in controls with P < or = 0.0003 for each enzyme. Preeclampsia is associated with a significant decrease in serum activities of three of the five hydrolases studied, a significant increase in urine enzyme activities in four of the five hydrolases studied, and a significant increase in the fractional excretion of all five lysosomal hydrolases.