Agonistic Angiotensin II Type 1 Receptor Autoantibodies in Postpartum Women with a History of Preeclampsia

Activating angiotensin II type 1 autoantibodies (AT1-AAs) develop in women with preeclampsia and may contribute to the disorder. Insulin resistance and serum concentrations of the antiangiogenic soluble fms-like tyrosine kinase 1 (sFlt-1) are also increased in women with preeclampsia compared with normal pregnancy. sFlt-1 and insulin resistance decrease substantially after delivery; however, significant group differences persist postpartum. Women who have had preeclampsia are at increased cardiovascular risk later in life. We measured AT1-AAs in groups of women with previous preeclampsia (n=29) and previous normal pregnancies (n=35) 18+/-9 months after the first completed pregnancy. These women had had sFlt-1, insulin resistance homeostasis model assessment score, and related cardiovascular risk factors measured. Activating antibodies were detected by the chronotropic response of cultured neonatal rat cardiomyocytes coupled with receptor-specific antagonists (losartan and prazosin). AT1-AAs were detected in 17.2% of women with previous preeclampsia versus 2.9% of women with previous uncomplicated pregnancies (P<0.05). In contrast, there was no difference in the prevalence of autoantibodies against the alpha1-adrenoceptor (10% of previous preeclamptic versus 14% of previous normal pregnant). Women with activating autoantibodies had significantly increased sFlt-1, reduced free vascular endothelial growth factor, and higher insulin resistance homeostasis model assessment values compared with autoantibody-negative women. These data suggest that, as with sFlt-1 and insulin resistance, the AT1-AA does not regress completely after delivery and, secondarily, that correlations exist among these variables. The impact of AT1-AA after preeclampsia, especially in the context of cardiovascular risk, remains to be determined.