Ultra-short peptides from edible dock protein alleviate vascular dysfunction in ovariectomy-induced menopausal rats by preserving immune homeostasis

Postmenopausal estrogen deficiency predisposes women to atherosclerosis and cardiovascular pathologies. Edible dock protein-derived enzymatic hydrolysates (EDP), rich in ultra-short peptides, exhibit potential vascular protective properties, yet their efficacy in postmenopausal settings remains undefined. Utilizing an ovariectomized (OVX) rat model, we demonstrate that EDP, while not restoring estrogen/progesterone levels, significantly counteracted OVX-induced hyperlipidemia (reduced total cholesterol/low-density lipoprotein cholesterol, LDL-C) and rescued acetylcholine-mediated vasodilation in high-dose treatment (H-EDP). Single-cell transcriptomics of thoracoabdominal aortas revealed OVX-driven immune dysregulation: monocyte/macrophage expansion, T-cell depletion, disrupted Treg/Th17 equilibrium, and pro-inflammatory T cell receptor (TCR)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. EDP rebalanced lymphoid populations (Treg/Th17 restoration), suppressed pro-inflammatory mediators, and enhanced anti-inflammatory transforming growth factor-β (TGF-β) signaling. In myeloid compartments, EDP attenuated neutrophilia and monocytosis while inhibiting atherogenic metabolism. Endothelial analysis highlighted EDP-enhanced lymphangiogenesis and immune-endothelial crosstalk via CXC chemokine ligand 12 (CXCL12)/CXC chemokine receptor 4 (CXCR4) axis. Smooth muscle cells exhibited EDP-mediated recovery of contractile SMC-Des populations, and modulation of leukocyte recruitment through vascular cell adhesion molecule-1 (VCAM1)-Integrin α4β1 interactions. Fibroblast profiling showed EDP-induced expansion of Fibro-Barx1 subsets, restoring ECM homeostasis via Jag1-Notch2 pathways. Critically, EDP achieved these effects independent of estrogen restoration, establishing it as a hormone-independent therapeutic strategy to mitigate vascular dysfunction and immune-metabolic dysregulation in estrogen-deficient states.