The Ghrelin/GHSR-1a Axis Attenuates Preeclampsia-like Features with Decidual Macrophage Reprogramming and Improved Placental Remodeling

Preeclampsia (PE) is a severe pregnancy-specific hypertensive disorder characterized by immune microenvironment dysregulation at the maternal–fetal interface, with decidual macrophage phenotypic imbalance being a key pathological feature. The Ghrelin/growth hormone secretagogue receptor-1a (GHSR-1a) axis exerts immunomodulatory and anti-inflammatory effects, but its role in regulating decidual macrophage infiltration and phenotypic marker expression in PE remains unclear. In this study, we first detected the expression of the Ghrelin/GHSR-1a axis in decidual tissues from 10 healthy pregnant women and 12 PE patients via immunohistochemistry (IHC). We then established a lipopolysaccharide (LPS)-induced PE-like rat model to investigate the axis’s functional role and underlying mechanisms. Intriguingly, clinical analysis revealed a severity-dependent compensatory escalation of the Ghrelin/GHSR-1a axis in PE decidual tissues, potentially representing an endogenous antagonistic response to pregnancy-associated pathological stress. In the animal model, exogenous Ghrelin supplementation reversed LPS-induced PE-like phenotypes, including hypertension, proteinuria, fetal growth restriction (FGR), and placental dysfunction, and alleviated pathological damage to the maternal liver, kidney, and placenta. Mechanistically, Ghrelin modulated decidual macrophage phenotypic marker expression by downregulating the M1 marker CD86 and upregulating the M2 marker CD163 and promoted trophoblast invasion and spiral artery remodeling by restoring laminin, α-cytokeratin 7 (α-CK7), and α-smooth muscle actin (α-SMA) expression in placental tissue. All protective effects of Ghrelin were abrogated by co-administration of D-lys-3-GHRP-6, a specific GHSR-1a antagonist, confirming the dependence on the Ghrelin/GHSR-1a axis. Collectively, our findings suggest that the Ghrelin/GHSR-1a axis is compensatorily upregulated in PE and may exert a protective role by regulating decidual macrophage phenotypic marker expression and improving placental function, providing preliminary evidence that this axis merits further investigation as a potential research target for PE.