Urinary tissue kallikrein excretion in black African women with severe pre‐eclampsia

Abstract

A study of tissue kallikrein excretion in African women with severe pre-eclampsia. Random untimed urine samples were collected from all women (n=198) recruited to this study; 66 women with severe pre-eclampsia, 66 normotensive pregnant women of similar length of gestation and 66 normotensive non-pregnant women. Urine specimens were analyzed for urinary tissue kallikrein using a selective, synthetic chromogenic tripeptide substrate (S2266) having the sequence H-D-Val-Leu-Arg-pNA. Urinary tissue kallikrein levels were decreased in women with severe pre-eclampsia compared with those of gestation matched normotensive pregnant women at 28 weeks of gestation (1.55+/-0.95 vs. 3.02+/-1.35 ng TK/microg protein; p<0.0001) and at near delivery date (1.21+/-0.53 vis. 3.11+/-1.2 ng TK/microg protein; p<0.0001). In the normotensive pregnant group, there was no significance difference in urinary tissue kallikrein excretion close at delivery date compared to 28 weeks of gestation (3.02+/-1.35 vs. 3.11+/-1.21 ngTK/microg protein; p=0.23). No statistical difference in urinary tissue kallikrein excretion was observed between normotensive pregnant and normotensive non pregnant women (3.02+/-1.35 vs. 2.97+/-1.12 ngTK/microg protein; p=0.16). Urinary tissue kallikrein excretion correlated positively with urinary creatinine levels at 28 weeks of gestation (r=0.69; p<0.0001) and close to delivery date (r=0.84; p<0.0001). There was no correlation between neonatal birthweight and urinary tissue kallikrein levels (r=-0.44; p=0.41). The decreased levels of urinary tissue kallikrein excretion in pre-eclamptic patients suggests an etiological role for this serine protease in hypertensive disorders of pregnancy.