Construction and application of therapeutic metal-polyphenol capsule for peripheral artery disease

Lesions of patients with peripheral artery disease (PAD) are in a harmful microenvironment, which features increased oxidative stress and inflammatory infiltration. Hence, it is essential to improve the microenvironment along with angiogenesis. In this study, metal-polyphenol capsules (Cu-EGCG), which combines the therapeutic anti-inflammatory and antioxidant activities of EGCG and the angiogenic activity of copper ions, were synthesized through coordination between EGCG and copper ions. The sustained release of the copper ions from Cu-EGCG was demonstrated in vitro, and biocompatible Cu-EGCG can scavenge intracellular ROS, reduce cell death in the presence of cytotoxic levels of ROS, and decrease the expression of pro-inflammatory cytokines (TNF-alpha, IL-6). Moreover, Cu-EGCG induced the secretion of vascular endothelial growth factor (VEGF) in a hindlimb ischaemia model of PAD. More importantly, the upregulated expression of platelet endothelial cell adhesion molecule-1 (CD31) and proliferating cell nuclear antigen (PCNA) in ischaemic tissues indicated the remarkable effect of Cu-EGCG on angiogenesis. In addition, Cu-EGCG showed significant blood recovery in ischaemic hindlimbs. Taking these results together, biocompatible Cu-EGCG with therapeutic functions holds great potential applications for PAD therapy.