Histochemical Evaluation of Placental Dipeptidyl Peptidase IV (CD26) in Pre-eclampsia: Enzyme Activity in Villous Trophoblast Indicates an Enhanced Likelihood of Gestational Hypertensive Disorders

PROBLEM: To determine whether differences in placental dipeptidyl peptidase IV (DPP IV, CD26) activities occurred in hypertensive complicated pregnancies as compared with uncomplicated pregnancies. METHOD: DPP IV activity was detected with H‐Gly‐Pro‐4M2NA as the substrate in placental cryostat sections from 65 patients with gestational hypertension and 67 patients with uncomplicated pregnancies. The graduated intensities of the reaction product in the villous trophoblast were scored semiquantitatively by light microscopy and were related to the relative frequencies of hypertensive disorders (proportional odds model). After detection of enzyme activity, the same tissue samples were homogenized and used for kinetic fluorometric measurements. RESULTS: Enhanced villous trophoblastic DPP IV activity was significantly associated with an increased frequency of proteinuric hypertension in pregnant women (cumulative odds ratio θ1 = 1.6; P < 0.01). CONCLUSION: This study demonstrates for the first time that increased villous trophoblastic DPP IV activity indicates an increased likelihood of the presence and of the severity of hypertensive disorders in pregnancy.