Complement factor H-point mutation promotes the development of preeclampsia-like phenotype with multiparity in mice

Preeclampsia, a severe pregnancy disorder associated with the placenta, remains incompletely understood in terms of its pathogenesis. Studies have suggested a link between complement activation and preeclampsia. In normal pregnancy, there is a moderate balance between complement-activating factor and regulatory protein. Fourteen percent of patients with preeclampsia/hemolysis, elevated liver enzymes and low platelet syndrome (HELLP syndrome) have a genetic mutation in complement regulators, leading to impaired regulation of the alternative complement pathway. However, the direct association between this and the precise role of pregnancy in triggering preeclampsia via complement system activation remains elusive.

Here, we evaluated the clinicopathological characteristics of preeclampsia in female mice harboring heterozygous mutations in complement factor H (CFH) (FH^W/R). Blood pressure, 24-h urine protein, blood biochemistry, routine blood tests, circulating complement activation factors, placental pathology, local complement activation and vascular activation were detected in both groups of mice.

Along with complement activation, these mice manifested hallmark features of human preeclampsia, including hypertension, proteinuria, increased lactic dehydrogenase, reduced placental weight, restricted fetal growth, characteristic histological alterations in the placenta and kidney, disrupted placental angiogenesis and renal endothelial cell injury.

We induced the key features of human preeclampsia in mice with heterozygous mutations in complement factor H,which suggest that individuals with increased genetic susceptibility to complement system overactivation may constitute a population which may have an increased risk to develop preeclampsia like phenotype of hypertension.