Luteolin Alleviates Vascular Senescence Through Retinoic Acid-Peroxisome Proliferator-Activated Receptor Signaling...

Background: Although luteolin (Lut) is well recognized for its anti-inflammatory and antioxidant effects, its potential role in preventing vascular senescence remains underexplored in primary vascular aging. This study aimed to investigate the anti-vascular-aging effects of Lut in both cellular and murine aging models and to elucidate its conserved molecular mechanisms across species. Methods: Canine and feline vascular endothelial cells (cVECs and fVECs) were subjected to doxorubicin-induced senescence, while senescence-accelerated mice prone 8 (SAMP8) received an 8-week dietary supplementation with Lut. Senescence markers, inflammatory cytokines, antioxidant activities, vascular biomechanics, and histological changes were assessed. Transcriptomic and metabolomic analyses were combined to identify molecular pathways. Statistical significance was determined by one-way analysis of variance with Tukey's or Games-Howell post hoc tests (p < 0.05). Results: Lut markedly reduced senescence-associated β-galactosidase activity, suppressed interleukin-6 and matrix metalloproteinase expression (p < 0.05), and enhanced superoxide dismutase activity and nicotinamide adenine dinucleotide levels (p < 0.05) in cVECs, fVECs, and SAMP8 sera. In aged mice, Lut alleviated arterial wall thickening and vascular inflammation, improved vascular biomechanics and systemic oxygenation (p < 0.05), and attenuated cardiac and hepatic inflammatory infiltration. Multi-omics analyses in cVECs revealed that Lut targets aldehyde dehydrogenase 1 to increase 9-cis retinoic acid, thereby activating the retinol X receptor-peroxisome proliferator-activated receptor (PPAR) network, which accelerates lipid clearance and oxidation. Consistent activation of this pathway was validated in murine vascular transcriptomes. Conclusions: These findings demonstrate that Lut delays vascular aging by activating the retinoic acid-PPAR axis and reprogramming lipid metabolism. This conserved mechanism was consistently observed in doxorubicin-induced cVEC senescence and the SAMP8 model, underscoring the robustness of Lut's action across distinct contexts of vascular aging.