Theaflavin-3,3′-digallate stabilizes vulnerable plaques by reprogramming metabolic homeostasis in neovascularization via HK2/TIGAR

Background

The leakage of vasa vasorum (VV) and intraplaque hemorrhage (IPH) pose significant risk for the instability and rupture of atherosclerosis (AS) plaques. The development of novel herbal monomers for anti-AS therapy has emerged as an increasingly promising strategy in combating cardiovascular diseases and stroke, which are frequently triggered by the rupture of vulnerable plaques.

Purpose

This study aimed to explore the protective effects of theaflavin-3,3′-digallate (TFDG) on plaque stability and its underlying mechanisms in preventing IPH through promoting VV maturation.

Methods

A carotid vulnerable plaque mouse model was established via tandem stenosis surgery. Non-targeted metabolomics and proteomics were integrated to identify the metabolic targets of TFDG. Molecular docking, co-immunoprecipitation, and western blotting were employed to elucidate the interactions within the HK2/TIGAR/MAPK pathway. Additionally, the expression levels of inflammatory cytokines and the energy metabolism status associated with metabolic reprogramming were evaluated.

Results

TFDG significantly modulated key serum inflammatory cytokines (IL-6, IL-1β, MCP-1, IL-4, NO) and lipid profiles (LDL, TC, HDL, TG), while suppressing AS plaque formation in Apoe^−/− mice. Quantitative analysis revealed that TFDG treatment increased fibrous cap thickness by 9.78 µm (p = 0.0085) and reduced lipid core size by 21% (p = 0.0004). Furthermore, TFDG improved the organization of the vascular lumen, restored pericyte synaptic function, and increased pericyte coverage by 8.42% (p < 0.001), while concomitantly decreasing pericyte apoptosis. These effects collectively reduced the incidence of IPH from 56.25% to 26.67%, thereby enhancing plaque stability. At the molecular level, TFDG downregulated HK2 expression and rebalanced the dynamics between glycolysis and OXPHOS through the TIGAR/p38/JNK signaling axis, thereby shifting VV metabolism toward a low-energy state. This mechanism consequently inhibited excessive pathological vascular sprouting and promoted a 24% increase in pericyte quiescence and adhesion (p = 0.0037), ultimately stabilizing the microvascular network architecture within plaques. While focusing on male mice adheres to standard protocols for AS modeling, future investigations should explicitly address potential sex differences in disease progression.

Conclusion

This study demonstrates that TFDG effectively inhibits AS progression via the HK2/TIGAR/MAPK axis, specifically by promoting the maturation of VV within plaques to reduce the incidence of IPH. The findings suggest that TFDG exhibits substantial potential for preventing acute cardiovascular and cerebrovascular events. The results provide promising directions and preliminary experimental evidence for future research aimed at preventing vulnerable plaque rupture.