Effect of iloprost on impaired anastomotic healing caused by 5-fluorouracil plus leucovorin

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.

International consensus statement regarding the use of animal models for research on anastomoses in the lower gastrointestinal tract

PURPOSE

This project aimed to reach consensus on the most appropriate animal models and outcome measures in research on anastomoses in the lower gastrointestinal tract (GIT). The physiology of anastomotic healing remains an important research topic in gastrointestinal surgery. Recent results from experimental studies are limited with regard to comparability and clinical translation.

METHODS

PubMed and EMBASE were searched for experimental studies investigating anastomotic healing in the lower GIT published between January 1, 2000 and December 31, 2014 to assess currently used models. All corresponding authors were invited for a Delphi-based analysis that consisted of two online survey rounds followed by a final online recommendation survey to reach consensus on the discussed topics.

RESULTS

Two hundred seventy-seven original articles were retrieved and 167 articles were included in the systematic review. Mice, rats, rabbits, pigs, and dogs are currently being used as animal models, with a large variety in surgical techniques and outcome measures. Forty-four corresponding authors participated in the Delphi analysis. In the first two rounds, 39/44 and 35/39 participants completed the survey. In the final meeting, 35 experts reached consensus on 76/122 items in six categories. Mouse, rat, and pig are considered appropriate animal models; rabbit and dog should be abandoned in research regarding bowel anastomoses. ARRIVE guidelines should be followed more strictly.

CONCLUSIONS

Consensus was reached on several recommendations for the use of animal models and outcome measurements in research on anastomoses of the lower GIT. Future research should take these suggestions into account to facilitate comparison and clinical translation of results.

Systematic review of experimental studies on intestinal anastomosis

BACKGROUND

The contribution of animal research to a reduction in clinical intestinal anastomotic leakage is unknown, despite numerous experimental studies. In view of the current societal call to replace, reduce and refine animal experiments, this study examined the quality of animal research related to anastomotic healing and leakage.

METHODS

Animal studies on intestinal anastomotic healing were retrieved systematically from PubMed and Embase. Study objective, conclusion and animal model were recorded. Reporting quality and internal validity (reporting of randomization and blinding) were assessed.

RESULTS

A total of 1342 studies were identified, with a rising publication rate. The objectives of most studies were therapeutic interventions (64·8 per cent) and identification of risk factors (27·5 per cent). Of 350 articles studying experimental therapies, 298 (85·1 per cent) reported a positive effect on anastomotic healing. On average, 44·7 per cent of relevant study characteristics were not reported, in particular details on anastomotic complications (31·6 per cent), use of antibiotics (75·7 per cent), sterile surgery (83·4 per cent) and postoperative analgesia (91·4 per cent). The proportion of studies with randomization, blinding of surgery and blinding of primary outcome assessment has increased in the past two decades but remains insufficient, being included in only 62·4, 4·9 and 8·5 per cent of publications respectively. Animal models varied widely in terms of species, method to compromise healing, intestinal segment and outcome measures used.

CONCLUSION

Animal research on anastomotic leakage is of poor quality and still increasing, contrary to societal aims. Reporting and study quality must improve if results are to impact on patients.

Pharmacological interventions for improved colonic anastomotic healing: A meta-analysis

AIM: To identify pharmaceuticals for the prophylaxis of anastomotic leakage (AL), we systematically reviewed studies on anastomosis repair after colorectal surgery.

METHODS: We searched PubMed and EMBASE for articles published between January 1975 and December 2012. We included studies in English with the primary purpose of promoting healing of anastomoses made in the colon or rectum under uncomplicated conditions. We excluded studies on adverse events from interventions, nutritional interventions or in situ physical supporting biomaterials. The primary outcome was biomechanical strength or AL. We performed meta-analyses on therapeutic agents investigated by three or more independent research groups using the same outcome. The DerSimonian-Laird method for random effects was applied with P < 0.05.

RESULTS: Of the 56 different therapeutic agents assessed, 7 met our inclusion criteria for the meta-analysis. The prostacyclin analog iloprost increased the weighted mean of the early bursting pressure of colonic anastomoses in male rats by 60 mmHg (95%CI: 30-89) vs the controls, and the immunosuppressant tacrolimus increased this value by 29 mmHg (95%CI: 4-53) vs the controls. Erythropoietin showed an enhancement of bursting pressure by 45 mmHg (95%CI: 14-76). The anabolic compound growth hormone augmented the anastomotic strength by 21 mmHg (95%CI: 7-35), possibly via the up-regulation of insulin-like growth factor-1, as this growth factor increased the bursting pressure by 61 mmHg (95%CI: 43-79) via increased collagen deposition. Hyperbaric oxygen therapy increased the bursting pressure by 24 mmHg (95%CI: 13-34). Broad-spectrum matrix metalloproteinase inhibitors increased the bursting pressure by 48 mmHg (95%CI: 31-66) on postoperative days 3-4. In the only human study, the AL incidence was not significantly reduced in the 103 colorectal patients treated with aprotinin (11.7%) compared with the 113 placebo-treated patients (9.7%).

CONCLUSION: This systematic review identified only one randomized clinical trial and seven therapeutic agents from pre-clinical models that could be explored further for the prophylaxis of AL after colorectal surgery.

Effects of TachoSil and 5-fluorouracil on colonic anastomotic healing

BACKGROUND

The administration of intraperitoneal (IP) 5-fluorouracil (5-FU) during the early postoperative period after cytoreductive surgery can decrease local cancer recurrence but may also cause impairment of the anastomotic healing. This study examined the effects of the use of this therapy and of the anastomotic sealing with TachoSil, a fibrin-thrombin coated sealant (FTCS), on the healing of colon anastomoses.

MATERIALS AND METHODS

Forty male rats were divided into four groups (1-4, 10 rats each) that underwent transection and anastomosis of the left colon. The anastomoses were covered with FTCS in groups 2 and 4. Saline solution (2 mL/d-groups 1 and 2) or 5-FU (20 mg/kg/d; groups 3 and 4) was administered IP once daily for 3 d. Bursting pressure (BP) was recorded, and the anastomoses were examined macroscopically and graded histologically.

RESULTS

The relative weight loss was significantly higher in group 3 than in the other groups (P = 0.0004). Anastomotic dehiscence, postoperative adhesion formation, perianastomotic collections, and preanastomotic dilatation did not differ significantly among groups. BP was significantly lower in group 3 compared with all other groups (P = 0.001). Neoangiogenesis was significantly lower in group 3 compared with groups 1 and 2 (P = 0.05). Fibroblastic activity was significantly higher in group 1 compared with group 3 (P = 0.035). Inflammatory cell infiltration and collagen deposition did not differ significantly among groups.

CONCLUSIONS

Our results shown that the early postoperative IP chemotherapy with 5-FU impaired the healing of colon anastomoses. However, anastomotic sealing with FTCS reversed some of the negative effects of this therapy.

Iloprost reduces colonic injury in ischemic colitis in rats

PURPOSE

Evaluate the effects of iloprost administration in the early period of ischemic colitis and the mechanism that how these effects develop.

METHODS

Thirty two Wistar albino female rats with an average weight of 220g were divided into four groups of eight rats. In group 1 the rats were given iloprost and sacrificed after 24 hours and in group 2 they were sacrificed after 24 hours without any iloprost. The rats in group 3 were administrated iloprost and sacrificed after 72 hours and in group 4 they were sacrificed at 72th hour without iloprost. The differences between the groups as tissue damage, vascularization or apoptosis were assessed statistically.

RESULTS

Oxidative damage and apoptosis were less pronounced and vascularization was better developed in rats that were given iloprost and sacrificed at 24th hour later in contrast to the rats that were not treated with iloprost. But there was no statistical difference among the groups at 72th hour.

CONCLUSION

Iloprost inhibited leucocyte infiltration, decreased proinflammatory cytokines and enhanced angiogenesis so that the oxidative stress and inflammatory response decreased resulting in lesser tissue damage.

The integrity of colonic anastomoses following the intraperitoneal administration of oxaliplatin

INTRODUCTION

The purpose of this experimental study was to determine the effect of oxaliplatin on the integrity of colonic anastomoses which were under oxaliplatin administration.

MATERIALS AND METHODS

Thirty rats were randomized to two groups. After resection of a 1-cm segment of the transverse colon, an end-to-end sutured anastomosis was performed. Rats of the control group were injected with 3 ml of 0.9% sodium chloride solution and in the oxaliplatin group with 2.4 mg/kg of oxaliplatin intraperitoneally immediately after surgery and for seven postoperative days. All rats were sacrificed on the tenth postoperative day, and the anastomoses were examined macroscopically and graded histologically. Rats were measured for anastomotic bursting pressures and tissue hydroxyproline levels.

RESULTS

The body weight changes were significantly greater in the oxaliplatin group (p = 0.005). Anastomotic dehiscence occurred only in the oxaliplatin group. The adhesion formation was significantly increased in the group of oxaliplatin compared to the control group (p = 0.001). The colonic bursting pressure was significantly lower in the oxaliplatin group compared to the control group (p < 0.001). The mean inflammatory cell infiltration was significantly lower in the oxaliplatin group (1.00 vs. 2.33, p < 0.001). The mean neoagiogenesis was significantly lower in the oxaliplatin group (0.80 vs. 2.20, p < 0.001). The mean collagen deposition was significantly lower in the oxaliplatin group and the mean fibroblast activity was significantly lower in the oxaliplatin group (1.27 vs. 2.53, p < 0.001). Hydroxyproline concentration was significantly lower in the oxaliplatin group (p < 0.001).

CONCLUSION

Intra- and postoperative intraperitoneal administration of oxaliplatin definitely impairs healing of colonic anastomoses in rats.

Covering the colon anastomoses with amniotic membrane prevents the negative effects of early intraperitoneal 5-FU administration on anastomotic healing

PURPOSE

This study investigated whether covering the colonic anastomoses with amniotic membrane (AM) protects the anastomotic healing from the adverse effects of immediate 5-fluorouracil (5-FU) administration.

METHODS

One hundred twenty wistar albino rats were randomized to one of four groups (I-IV, 30 rats in each) and underwent a standardized left colon resection and anastomoses. The anastomoses of the rats in groups II (AM) and IV (5-FU + AM) were covered with AM. Saline solution (2 ml/day; groups I (control) and II) or 5-FU (20 mg/kg/day; groups III (5-FU) and IV) was administered to the rats intraperitoneally once daily from the day of operation until sacrificed. Half of each group was sacrificed on the postoperative day 4 (IA, IIA, IIIA, and IVA) and other half on the postoperative day 8 (IB, IIB, IIIB, and IVB), and their anastomoses were evaluated when sacrificed.

RESULTS

The dehiscence rate of anastomotic dehiscence and adhesion formation were significantly higher in groups IIIA and IIIB compared with groups IVA and IVB, respectively. Bursting pressure was significantly higher in the 5-FU + AM groups than in the 5-FU groups. The inflammatory cell infiltration was significantly lower in groups IIIA and IVA compared with group IA, in groups IIIB and IVB compared with group IB, and in group IVA compared with group IIIA. Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline levels were significantly higher in the 5FU + AM groups compared with control and 5-FU groups. Malondialdehyde levels were significantly higher in the 5-FU groups than in the 5-FU + AM groups.

CONCLUSION

Covering colon anastomoses with AM protects them, preventing leakage and reversing the negative effects of 5-FU administration.

Healing of colonic anastomoses after immediate postoperative intraperitoneal administration of oxaliplatin

AIM

The aim of this experimental study was to investigate the effect of intraperitoneal administration of oxaliplatin on the healing of colonic anastomoses when injected immediately after colon resection.

MATERIALS AND METHODS

Thirty male Wistar rats were used. During the operation, the rats were randomized to two groups of 15 rats each. Immediately after colonic anastomoses were performed, the rats were injected intraperitoneally with either 3 ml of 0.9% NaCl solution or oxaliplatin (2.4 mg/kg body weight) depending on their group. All rats were killed on the eighth postoperative day. The anastomoses were examined macroscopically. The anastomotic bursting pressures were recorded, the anastomoses graded histologically, and the hydroxyproline tissue contents determined.

RESULTS

Anastomotic leakage was noted in four rats (26.7%) of the oxaliplatin group, whereas no anastomotic dehiscence was detected among rats of the control group (p = 0.016). The adhesion formation at the anastomotic sites and the inflammatory cell infiltration were significantly higher in the oxaliplatin group than in the control group (p = 0.001). The bursting pressures (p = 0.001), the hydroxyproline tissue content (p = 0.001), the neoangiogenesis (p = 0.033), the fibroblast activity (p = 0.001), and the collagen deposition (p = 0.001) were significantly lower in the oxaliplatin group in comparison to the control group.

CONCLUSION

The immediate postoperative intraperitoneal administration of oxaliplatin seems to impair healing of colonic anastomoses in rats.