The effect of Bosentan on healing of colonic anastomosis

Therapeutic improvement of colonic anastomotic healing under complicated conditions: A systematic review

AIM: To identify therapeutic agents for the prophylaxis of gastrointestinal anastomotic leakage (AL) under complicated conditions.

METHODS: The PubMed and EMBASE databases were searched for English articles published between January 1975 and September 2014. Studies with the primary purpose of improving anastomotic healing in the colon or rectum under complicated preoperative and/or intraoperative conditions were included. We excluded studies investigating the adverse effects or risk assessment of an active intervention. Furthermore, investigations of biophysical materials, sealants, electrical stimulation and nutrients were excluded. The primary study outcome was biomechanical anastomotic strength or AL. The meta-analysis focused on therapeutic agents that were investigated in one animal model using the same outcome by at least three independent research groups.

RESULTS: The 65 studies included were divided into 7 different complicated animal models: Bowel ischemia, ischemia/reperfusion, bowel obstruction, obstructive jaundice, peritonitis, chemotherapy and radiotherapy. In total, 48 different therapeutic compounds were examined. The majority of investigated agents (65%) were reported as beneficial for anastomotic healing. Twelve of the agents (25%) were tested more than once in the same model, whereas 13 (27%) of the agents were tested in two or more models of complicated healing. Two therapeutic agents met our inclusion criteria for the meta-analysis. Postoperative hyperbaric oxygen therapy significantly increased anastomotic bursting pressure in ischemic colon anastomoses by a mean of 28 mmHg (95%CI: 17 to 39 mmHg, P < 0.00001). Granulocyte macrophage-colony stimulating factor failed to show a significant increase in anastomotic bursting pressure (95%CI: -20 to 21 mmHg, P = 0.97) vs controls in experimental chemotherapeutic models.

CONCLUSION: This systematic review identified potential therapeutic agents, but more studies are needed before concluding that any of these are useful for AL prophylaxis.

Effect of Ozone Therapy (OT) on Healing of Colonic Anastomosis in a Rat Model of Peritonitis

BACKGROUND

Ozone is a three-oxygen molecule (O3). Ozone therapy (OT) is systematically effective when pathological inflammatory and immunologic processes are activated. Among of these conditions are wound healing, macular degeneration related to aging, and conditions that are ischemic or infectious.

AIMS

The aim of this study was to determine the effects of OT on wound healing of intestinal anastomosis in the presence of peritonitis in a rat model.

STUDY DESIGN

Animal experimentation.

METHODS

A total of 40 Wistar albino rats were randomized into four groups (n=10) including: sham (S), peritonitis (P), ozone 0 (O0), and ozone 24 (O24). In group S, only cecal dissection was carried out. The S group had only a cecal dissection and intestinal anastomosis performed, but no peritonitis. In all other groups, cecal ligation and puncture (CLP) followed the cecal dissection to induce bacterial peritonitis. 24 h after puncture, a cecal resection and ileocolic anastomosis were performed. In group P, 24 h after CLP, a cecal resection and ileocolic anastomosis were performed and no ozone was administered. In group O0, immediately after the anastomosis, and in group O24, starting 24 hours after the anastomosis, an intraperitoneal 1 mg/kg/day ozone administration was applied for seven days. On the seventh day the animals were sacrificed, the anastomotic bursting pressures (BP) and the hydroxyproline values of the anastomotic tissues were measured, and histopathologic examination of the anastomotic segment was carried out.

RESULTS

The highest BP was in group S, with 211±23.13 mmHg. The mean BP of group P was 141±56.25 mmHg, which was significantly lower than in the other two peritonitis groups that received ozone therapy, group O0 and O24, where it was 192±22 and 166±45 mmHg, respectively (p<0.05). The difference in the BP between groups O0 and O24 was not statistically significant (p>0.05). Histopathologic analyses of the anastomotic segments determined there was significantly more oedema and necrosis in the control group rats, and collagen deposition in the anastomotic tissue was significantly higher in the ozone-treated groups on postoperative day 7. Hydroxyproline levels were significantly higher in groups O0 and O24 compared to the peritonitis group (P).

CONCLUSION

Ozone therapy has a beneficial effect on anastomotic healing of the colon in the presence of peritonitis.

A comparison of two anastomotic techniques in the jejunum of the goat

This study was carried out to test two different anastomotic techniques to identify advantages and disadvantages of each technique in goats. All animals were under local infiltration anaesthesia. A five-cm length of jejunum was resected from the first part of the jejunum and end to end anastomosis using 3-0 Polygalactin-910 with one row of sero-submoucosal interrupted sutures (SSIS) group, and one row of horizontal mattress interrupted sutures (HMIS) group. Two animals from each group were euthanized on the 4th, 14th and 21st postoperative days. A 7-cm segment of jejunum including the anastomosed area was resected from each animal. There was no significant adhesion between anastomosis area and surrounded tissues observed in SSIS animals, while there was significant adhesion between anastomosis area and surrounded tissues which were observed in HMIS animals. Stenosis degree was lower in the SSIS than the HMIS group. The bursting pressure was higher in the SSIS than the HMIS group. Macroscopic evaluation indicated that the anastomotic line mucosa was abridged better with less local edema in the SSIS group. Histological evaluation in the SSIS group showed almost all parameters such as epithelial recovery and repair of submucosal-mucosal layer demonstrated better healing compared to the HMIS group.

Does sildenafil reverse the adverse effects of ischemia on ischemic colon anastomosis: yes, 'no'

INTRODUCTION

Sildenafil may lead an improvement in anastomotic healing of ischemic left colon anastomosis.

METHODS

Thirty-six male Wistar albino rats were randomized into four experimental groups (n=9 in each group). In group 1, a well-perfused left colonic segment was transected, and free ends were anatomosed. In groups 2, 3 and 4 animals underwent a standardized surgical procedure to induce ischemic left colon anastomosis. Group 2 animals received only tap water. In groups 3 and 4 animals received 10mg/kg/body-weight and 20mg/kg/body-weight sildenafil, single dose a day during 4 days, respectively. Rats were sacrificed on day 4 following operation. Anastomotic integrity, intra-peritoneal adhesion scores, anastomotic bursting pressures and tissue hydroxyproline levels were recorded. Histopathological examination of the anastomosis was also performed.

RESULTS

There was no statistically significant difference among groups with respect to anastomotic integrity (p=0.142) but ischemia decreased the anastomotic bursting pressure. The mean bursting pressure values were 78.8+/-24.1, 43.3+/-26, 55.1+/-32.4, and 43.3+/-20.4 in groups 1, 2, 3, and 4, respectively. Group 1 had the highest values whereas; there was no statistically significant difference between groups 1 and 3. There was no statistically significant difference among groups 2, 3, and 4 with respect to tissue hydroxyproline levels, adhesion scores and the Chiu scores. The highest inflammatory cell presence in the granulation tissue was detected in group 2, whereas the lowest was detected in group 4 (p=0.0001). The highest fibroblast infiltration in the granulation tissue was detected in group 1 (p=0.045).

DISCUSSION

Our results showed that 10mg/kg sildenafil decreased the adverse effects of ischemia on the healing of ischemic left colon anastomosis. Additional investigations are needed to confirm the effects of phosphodiesterase-5 inhibitors in ischemic colon anastomosis models.

The effects of endothelin receptor blockade by bosentan on the healing of a bowel anastomosis in an experimental Crohn's disease model

OBJECTIVE

It was previously described that endothelins may contribute to the pathogenesis of Crohn's disease. In this study, it was aimed to investigate the effects of endothelin receptor blockade by bosentan on the healing of a bowel anastomosis in an experimental Crohn's disease model.

MATERIAL AND METHODS

Twenty-eight Sprague-Dawley rats were divided into four groups. Groups I and II were used as sham-operated and control groups, respectively. Bowel inflammation induced by intrajejunal injection of iodoacetamide in groups III and IV. Rats in group IV were treated with oral preparation of bosentan 60 mg/kg/day. Three days after induction of the inflammation, partial resection of test loop and anastomosis was performed. Re-laparotomy was performed, anastomosis bursting pressures and peritonitis scores were measured, and tissue samples were obtained for the measurements of tissue hydroxylproline level and mucosal damage index 4 days later.

RESULTS

The mean mucosal damage index and peritonitis score of group IV were significantly lower, and the mean tissue hydroxyproline level and anastomotic bursting pressure of group IV were significantly higher than those of group III.

CONCLUSION

The blockade of endothelin receptors by bosentan decreases the severity of iodoacetamide induced intestinal inflammation, increases the wound healing in the inflamed intestinal tissue, and decreases the severity of peritonitis.