Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2016; 22(17): 4321-4329
Published online May 7, 2016. doi: 10.3748/wjg.v22.i17.4321
Growth hormone abolishes the negative effects of everolimus on intestinal wound healing
Markus Alexander Küper, Sebastian Trütschel, Jürgen Weinreich, Alfred Königsrainer, Stefan Beckert
Markus Alexander Küper, Sebastian Trütschel, Jürgen Weinreich, Alfred Königsrainer, Stefan Beckert, Department of General, Visceral and Transplant Surgery, University of Tübingen, 72076 Tübingen, Germany
Markus Alexander Küper, BG Trauma Center, University of Tübingen, D-72076 Tübingen, Germany
Author contributions: Küper MA, Königsrainer A and Beckert S concepted the study; Küper MA, Trütschel S and Weinreich J performed the animal studies and did the laboratory work; Küper MA, Trütschel S and Beckert S interpreted the results and did literature research; all authors wrote and revised this manuscript.
Institutional review board statement: Tierschutzgesetz in der Fassung der Bekanntmachung vom 18.05.2006.
Institutional animal care and use committee statement: All procedures were reviewed and approved by the Institutional animal care and use committee of the university of Tubingen.
Conflict-of-interest statement: All authors declare that they do not have any conflict of interest regarding this study.
Data sharing statement: The original datasets and histological specimen are available from the corresponding author at mkueper@hotmail.com.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Markus Alexander Küper, MD, BG Trauma Center, University of Tübingen, Schnarrenbergstraße 95, D-72076 Tübingen, Germany. mkueper@hotmail.com
Telephone: +49-7071-6063920 Fax: +49-7071-6061002
Received: January 9, 2016
Peer-review started: January 10, 2016
First decision: January 28, 2016
Revised: February 10, 2016
Accepted: March 2, 2016
Article in press: March 2, 2016
Published online: May 7, 2016
Processing time: 111 Days and 12.4 Hours
Abstract

AIM: To investigate whether the simultaneous treatment with human growth hormone (hGH) abolishes the negative effects of everolimus on anastomotic healing.

METHODS: Forty-eight male Sprague-Dawley-rats were randomized to three groups of 16 animals each (I: vehicle; II: everolimus 3 mg/kg po; III: everolimus 3 mg/kg po + hGH 2.5 mg/kg sc). Animals were pre-treated with hGH and/or everolimus daily for seven days. Then a standard anastomosis was created in the descending colon and treatment was continued for another seven days. The anastomosis was resected in toto and the bursting pressure was assessed as a mechanical parameter of intestinal healing. Moreover, biochemical (Hydroxyproline, PCNA, MPO, MMP-2 and MMP-9) and histological (cell density, angiogenesis, amount of granulation tissue) parameters of intestinal healing were assessed.

RESULTS: Anastomotic bursting pressure was significantly reduced by everolimus and a simultaneous treatment with hGH resulted in considerably higher values (I: 134 ± 19 mmHg, II: 85 ± 25 mmHg, III: 114 ± 25 mmHg; P < 0.05, I vs II; P = 0.09, I vs III and II vs III) Hydroxyproline concentration was significantly increased by hGH compared to everolimus alone (I: 14.9 ± 2.5 μg/mg, II: 8.9 ± 3.6 μg/mg, III: 11.9 ± 2.8 μg/mg; P < 0.05, I vs II/III and II vs III). The number of MPO-positive cells was reduced significantly by hGH compared to everolimus alone (I: 10 ± 1 n/mm², II: 15 ± 3 n/mm², III: 9 ± 2 n/mm²; P < 0.05, I vs II and II vs III), while the number of PCNA-positive cells were increased by hGH (I: 28 ± 3 /mm², II: 12 ± 3 /mm², III: 26 ± 12 /mm²; P < 0.05, I vs II and II vs III). Corresponding to these biochemical findings, HE-histology revealed significantly increased amount of granulation tissue in hGH-treated animals.

CONCLUSION: Inhibition of intestinal wound healing by everolimus is partially neutralized by simultaeous treatment with hGH. Both inflammation as well as collagen deposition is influenced by hGH.

Keywords: Wound healing; Everolimus; Human growth hormone; Immunosuppression; mTOR-inhibitor; Growth hormone; Anastomotic healing

Core tip: Patients undergoing transplantation are set onto immunosuppressive medication afterwards. One agent is everolimus out of the group of the mTOR-inhibitors. Everolimus has been shown to inhibit healing of intestinal anastomoses by influencing the inflammatory phase of wound healing. Human growth hormone (hGH) has been shown to improve wound healing by increasing the amount of collagen in the wound. In this animal study we could demonstrate for the first time that a combined perioperative treatment with everolimus and hGH results in improved intestinal wound healing compared with everolimus alone. These results might be a step towards safer immunosuppression in transplanted patients.