Topical Erythropoietin Treatment Accelerates the Healing of Cutaneous Burn Wounds in Diabetic Pigs Through an Aquaporin-3–Dependent Mechanism Saher Hamed, 1 Yehuda Ullmann, 2 Dana Egozi, 2 Aviad Keren, 3 Essam Daod, 2 Omer Anis, 2 Hoda Kabha, 1 Mark Belokopytov, 1 Manal Ashkar, 1 Rona Shofti, 3 Asaph Zaretsky, 3 Michal Schlesinger, 3 Luc Teot, 4 and Paul Y. Liu 5 Diabetes 2017;66:2254–2265 | https://doi.org/10.2337/db16-1205 We have previously reported that the topical application of erythropoietin (EPO) to cutaneous wounds in rats and mice with experimentally induced diabetes accelerates their healing by stimulating angiogenesis, reepithelialization, and collagen deposition, and by suppressing the inflammatory response and apoptosis. Aquaporins (AQPs) are integral membrane proteins whose function is to regulate intracel- lular fluid hemostasis by enabling the transport of water and glycerol. AQP3 is the AQP that is expressed in the skin where it facilitates cell migration and proliferation and re- epithelialization during wound healing. In this report, we provide the results of an investigation that examined the contribution of AQP3 to the mechanism of EPO action on the healing of burn wounds in the skin of pigs with experi- mentally induced type 1 diabetes. We found that topical EPO treatment of the burns accelerated their healing through an AQP3-dependent mechanism that activates angiogenesis, triggers collagen and hyaluronic acid synthesis and the for- mation of the extracellular matrix (ECM), and stimulates reepithelialization by keratinocytes. We also found that incorporating fibronectin, a crucial constituent of the ECM, into the topical EPO-containing gel, can potentiate the accel- erating action of EPO on the healing of the burn injury. According to the U.S. Centers for Disease Control and Pre- vention, .400 million people worldwide have diabetes. The Centers for Disease Control and Prevention also estimates that 5% of these individuals will develop a diabetic skin ulcer (DSU) and that 1% will require a lower-extremity am- putation. Despite many advances in wound care and man- agement (1), wound healing in diabetes is delayed because all phases of the orchestrated cascade of cellular and bio- chemical events of wound healing are disrupted (2–4). Additionally, the healing of a DSU is delayed because of impaired angiogenesis, insufficient blood flow, increased in- flammation, diminished proliferation of fibroblasts (5), and reduced reepithelialization by keratinocytes (6–8). The glycoprotein hormone erythropoietin (EPO) regulates red blood cell mass and is an approved drug for treating anemia. EPO also has nonhematopoietic targets in the skin, and we have shown (9) that these targets participate in the healing of skin wounds. We previously reported that the healing of cutaneous wounds in rats and mice with exper- imentally induced diabetes is accelerated after the topical application of recombinant human EPO to the cutaneous wounds by stimulating angiogenesis, reepithelialization, and collagen deposition, and by suppressing the inflamma- tory response and apoptosis (10). The beneficial actions of EPO on wound healing in diabetes are complemented by fibronectin (FN). FN facilitates the formation of the pro- visional wound matrix and prevents its dissociation (11). Aquaporins (AQPs) are integral membrane proteins whose function is to regulate intracellular fluid hemostasis by enabling the transport of water and glycerol. AQPs are expressed in the plasma membranes of keratinocytes in the basal layer of the skin and the medullary collecting ducts of 1 Department of Research & Development, Remedor Biomed Ltd, Nazareth Illit, Israel 2 Department of Plastic Surgery, Rambam Health Care Campus, Haifa, Israel 3 Skin Research Laboratory, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel 4 Department of Plastic & Reconstructive Surgery and Wound Healing, Hopital Lapeyronie, Montpellier, France 5 Department of Plastic Surgery, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, RI Corresponding author: Saher Hamed, saher@remedor.com. Received 4 October 2016 and accepted 24 April 2017. © 2017 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals .org/content/license. 2254 Diabetes Volume 66, August 2017 COMPLICATIONS Downloaded from http://diabetesjournals.org/diabetes/article-pdf/66/8/2254/537786/db161205.pdf by guest on 31 January 2024