*Article* **Local Growth Hormone Therapy for Pressure Ulcer Healing on a Human Skin Mouse Model**

**Lara Cristóbal 1,2,3, Nerea de los Reyes 1, Miguel A. Ortega 2,3,4, Melchor Álvarez-Mon 2,3,5, Natalio García-Honduvilla 2,3,4,6, Julia Buján 2,3,4 and Andrés A. Maldonado 2,3,7,\***


Received: 10 August 2019; Accepted: 20 August 2019; Published: 26 August 2019

**Abstract:** The growth hormone is involved in skin homeostasis and wound healing. We hypothesize whether it is possible to improve pressure ulcer (PU) healing by locally applying the recombinant human growth hormone (rhGH) in a human skin mouse model. Non-obese diabetic/severe combined immunodeficient mice (*n* = 10) were engrafted with a full-thickness human skin graft. After 60 days with stable grafts, human skin underwent three cycles of ischemia-reperfusion with a compression device to create a PU. Mice were classified into two groups: rhGH treatment group (*n* = 5) and control group (*n* = 5). In the rhGH group for local intradermal injections, each had 0.15 mg (0.5IU) applied to the PU edges, once per week for four weeks. Evaluation of the wound healing was conducted with photographic and visual assessments, and histological analysis was performed after complete wound healing. The results showed a healing rate twice as fast in the rhGH group compared to the control group (1.25 ± 0.33 mm2/day versus 0.61 ± 0.27 mm2/day; *p*-value < 0.05), with a faster healing rate during the first 30 days. The rhGH group showed thicker skin (1953 ± 457 μm versus 1060 ± 208 μm; *p*-value < 0.05) in the repaired area, with a significant decrease in collagen type I/III ratio at wound closure (62 days, range 60–70). Local administration of the rhGH accelerates PU healing in our model. The rhGH may have a clinical use in pressure ulcer treatment.

**Keywords:** growth hormone; human skin graft; pressure ulcer treatment; wound healing
