Chrysalin
Healing & RecoveryAlso known as: TP508, Thrombin Peptide 508, Chrysalin Peptide, rusalatide acetate
Mechanism
Chrysalin (TP508) is a 23-amino-acid peptide derived from human thrombin — the enzyme that forms blood clots. But instead of promoting clotting, TP508 activates tissue repair pathways that are normally triggered at wound sites when thrombin is present. It accelerates bone fracture healing, wound closure, and tissue regeneration by stimulating stem cell recruitment and new blood vessel formation. It reached Phase 2 clinical trials for bone fracture repair, showing faster healing of distal radius (wrist) fractures.
Technical detail
Chrysalin/TP508 (rusalatide acetate) is a 23-amino-acid synthetic peptide (residues 508-530 of human prothrombin). It represents the receptor-binding domain of thrombin but lacks proteolytic (clotting) activity. Mechanism: binds a non-proteolytic thrombin receptor on stem cells and endothelial cells (distinct from PAR-1), activating: (1) Angiogenesis — VEGF-independent neovascularization, endothelial cell proliferation and tube formation; (2) Stem cell recruitment — mobilizes mesenchymal stem cells to injury sites; (3) Osteogenesis — stimulates osteoblast differentiation and bone matrix deposition (BMP-2 pathway synergy); (4) Nitric oxide signaling — activates eNOS for vasodilation and tissue perfusion at injury sites; (5) Anti-inflammatory — reduces TNF-α and IL-1β at injury sites. Phase I/II for distal radius fractures: accelerated radiographic healing by 37% vs. placebo (injected at fracture site during casting). Also studied for diabetic foot ulcers. OrthoLogic (now Capstone Therapeutics) was the developer.