EXPRESSION OF RENIN AND ANGIOTENSINOGEN GENES IN PREECLAMPTIC AND NORMAL HUMAN PLACENTAL TISSUE

Objective: We have quantitated renin activity and angiotensinogen and measured the expression of renin and angiotensinogen genes in placenta s from normal and preeclamptic subjects to determine if tissue renin s ystem parameters are elevated in preeclampsia. Methods: Tissue renin a ctivity and tissue levels of angiotensinogen were measured by enzymati c techniques, and renin and angiotensinogen mRNA were quantitated by b lot hybrodization in placentae from young nulliparous black women with preeclampsia and normal controls. Main Outcome: Placental ischemia is considered one of the etiological factors of preeclampsia. All compon ents of the renin system are present in human placenta, and enhanced e xpression of this system may contribute to placental ischemia. Results : Tissue active renin concentration was slightly elevated in preeclamp tics (130 +/- 20 ng Al/mg protein/h) versus controls (80 +/- 20), but angiotensinogen levels did not differ. In preeclamptic placentae renin mRNA was also elevated (249 +/- 35 versus 207 +/- 42 arbitrary densit y units/mug total RNA), and angiotensinogen mRNA levels were the same as normal placentae. In normal, but not in preeclamptic placentae, a s ignificant linear correlation was apparent between renin mRNA and tota l renin concentration (r = 0.87, p < 0.002). Conclusions: Tissue renin systems may well contribute to the hypertension associated with pregn ancy; however, larger study populations will be required to verify thi s.