Difficult-to-treat, chronic wounds in preclinical models healed with normal scar-free skin after treatment with an acellular product discovered at Mayo Clinic. Derived from platelets, the purified exosomal product, known as PEP, was used to deliver healing messages into cells of preclinical animal models of ischemic wounds. The Mayo Clinic research team documented restoration of skin integrity, hair follicles, sweat glands, skin oils and normal hydration.