Influence of misoprostol, a synthetic prostaglandin E1 analog, on the healing of colonic anastomoses in rats

Effects of Lornoxicam on Anastomotic Healing: A Randomized, Blinded, Placebo-Control Experimental Study

Introduction and Aim. With the implementation of multimodal analgesia regimens, Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) are often administered for optimal pain control and reduction of opioid use. The aim of the study was to examine the effects of lornoxicam, a NSAID, on anastomotic healing employing an animal model. Materials and Methods. A total of 28 Wistar rats were randomly assigned in two groups. All animals underwent ascending colonic transection followed by an end-to-end hand sewn anastomosis. Group 1 received intraperitoneally lornoxicam before and daily after surgery. Group 2 received intraperitoneally an equal volume of placebo. Half of the animals in each group were euthanized on the 3rd pod and the remaining on the 7th pod. Macro- and microscopic indicators of anastomotic healing were compared using a two-tailed Fisher exact test. Results. The lornoxicam group significantly decreased fibroblast in growth and reepithelization of the mucosa at the anastomotic site on the 3rd pod and significantly increased occurrence of deep reaching defects, necrosis, and microabscess on the 7th pod. Conclusion. Lornoxicam administration during the perioperative period adversely affects histologic parameters of intestinal anastomotic healing. These effects of lornoxicam administration were not found to induce significant increase of anastomotic dehiscence in the rat model.

Effect of infliximab on the healing of intestinal anastomosis. An experimental study in rats

BACKGROUND AND AIM

Infliximab is effective in the induction and maintenance of remission in Crohn's disease. Whether, the perioperative administration of anti-TNF-a compromises intestinal healing leading to anastomotic failure and increased risk of postoperative complications, remains controversial. The aim of the study was to evaluate the effect of Infliximab on intestinal anastomosis healing.

METHODS

Fifty six wistar rats were divided into 4 groups: (a) 20 rats were subjected to excision of part of the terminal ileum followed by anastomosis which was evaluated on the 3rd or 7th postoperative day; (b) 20 rats received Infliximab and thereafter, the same surgical protocol as group (a) was followed; (c) 8 rats received Infliximab and served as relative control group; and (d) 8 served as absolute control group. Bursting pressure was used for testing intestinal healing. Additionally, the anastomoses were examined macroscopically, histologically and immunohistochemically for TGFb1, MMP1, MMP2 and Collagen V. The results were confirmed by Western blot analysis.

RESULTS

There were no significant differences in bursting pressures and septic intra-abdominal events among non-Infliximab (a) and Infliximab-treated (b) groups. Infliximab-treated (b) group showed mild to moderate inflammation, whereas the non-Infliximab (a) group exhibited severe inflammation. Expression of TGFb1, MMP2 and collagen V was significantly higher in the Infliximab-treated (b) group.

CONCLUSION

Infliximab seems to influence intestinal healing in terms of less inflammatory activity and higher tissue remodeling activity.

The effect of carbon dioxide pneumoperitoneum on the healing colonic anastomosis in rats

PURPOSE

To investigate the effects of pneumoperitoneum on colonic anastomosis healing.

METHODS

Colonic anastomosis was performed in 120 rats divided into four groups: Group I - pneumoperitoneum before laparotomy, Group II - pneumoperitoneum after laparorrhaphy, Group III - pneumoperitoneum before laparotomy and after laparorrhaphy, Group IV - no pneumoperitoneum (control group). Pneumoperitoneum pressure was 5 mmHg. Animals were killed on the 3rd, 7th and 14th postoperative day. Histopathological features, anastomosis breaking strength, collagen histomorphometry and hydroxyproline concentration were assessed.

RESULTS

Breaking strength between groups: (day 3, p=0.165; day 7, p=0.219; day 14, p=0.539). Histopathology revealed that group II had, on day 7, less infiltration of mononuclear cells (p=0.006), greater infiltration of polymorphonuclear cells (p=0.001) and greater necrosis (p=0.001); and on day 14, less fibrosis. Histomorphometry revealed a decrease in collagen in groups I and III (p<0.001) on day 7 and an increase in groups I and II on day 14 (p<0.001). Hydroxyproline concentration was similar for groups on days 3 (p=0.152), 7 (p=0.913) or 14 (p=0.981).

CONCLUSION

Carbon dioxide does not impair the healing of colonic anastomosis in rats.

Effects of bromopride on the healing of left colonic anastomoses in rats with induced abdominal sepsis

PURPOSE

To evaluate the effects of bromopride on the healing of left colonic anastomoses in rats with induced abdominal sepsis.

METHODS

Forty rats were divided into two groups to receive either bromopride (experimental group- E) or saline (control group- C). Each group was divided into subgroups of ten animals each to be euthanized on third (E3 and C3) or seventh day (E7 and C7) after surgery. Sepsis was induced by cecal ligation and puncture. The rats underwent segmental left colon resection and end-to-end anastomosis. Adhesion formation, tensile strength and hydroxyproline concentration were assessed. Histomorphometry of collagen and histopathological analysis were also performed.

RESULTS

On postoperative third day, anastomoses in bromopride-treated animals showed lower tensile strength (p=0.02) and greater reduction in hydroxyproline concentration (p=0.04) than in control animals. There was no statistical difference in these parameters on seventh day, and the remaining parameters were similar across subgroups. Collagen content was also similar across subgroups.

CONCLUSION

In the presence of abdominal sepsis, the administration of bromopride was associated with decreased tensile strength and hydroxyproline concentration in left colonic anastomoses in rats three days after surgery.

Evaluation of the effects of S-methylisothiourea hemisulfate, an inducible nitric oxide synthase inhibitor, on the healing of colonic anastomosis in rats

PURPOSE

To evaluate the effects of S-methylisothiourea hemisulfate (SMT) on the healing of colonic anastomosis in rats.

METHODS

Sixty rats Wistar were distributed into two groups of 30 animals: experimental (E) and control C). The animals of experimental group received intraperitoneal SMT at 50 mg/kg/dose every 12 hours for 72 hours. The control group received intraperitoneal saline at the same volume of SMT. The rats were subdivided into subgroups groups of 10 for euthanasia on the third, seventh, and 14th postoperative days (POD). We evaluated clinical and weight evolution, breaking strength and histopathology; also, a blood sample was collected for serum dosage of nitrite/nitrate.

RESULTS

There was more vascular neoformation (p=0.006) and granulation (p=0.002) in the E3 group, and more mononuclear infiltrates in the C3 group (p=0.041). There was also more edema in the C14 group (p=0.008). There was no statistically significant difference in breaking strength, nitrite/nitrate dosage, and the remaining histopathological parameters.

CONCLUSION

The use of S-methylisothiourea hemisulfate improved the healing of colonic anastomosis in rats on the third postoperative day by accelerating the proliferative stage of healing, but without interfering with the breaking strength of the anastomosis.

Does metoclopramide impair anastomotic healing of the left colon of rats?

PURPOSE: To evaluate the effects of metoclopramide on the formation of adhesion and the healing of left colonic anastomoses in rats. METHODS: Forty rats underwent sectioning of the left colon and end-to-end anastomosis and were divided into two groups of 20 animals for the administration of metoclopramide (experimental group - E) or saline solution (control group - C). Each group was divided into subgroups of 10 animals each to be killed on the third (E3 and C3) or seventh postoperative day (E7 and C7). Adhesion was assessed, and a colonic segment containing the anastomosis was removed for analysis of breaking strength and hydroxyproline concentration. RESULTS: There were no deaths or dehiscence on the 3rd postoperative day. There was one death and one blocked anastomotic dehiscence in the E7 group. No significant differences between groups were found in the analysis of clinical outcome, intra-cavity adhesion, adhesion to the anastomosis or breaking strength on the 3rd and 7th postoperative day. Hydroxyproline concentration was higher in the control group on the 3rd (p=0.006) but not on the 7th postoperative day (p=0.241). CONCLUSION: Metoclopramide did not have harmful effects on the healing of intestinal anastomoses in rats.

Analysis of the tensile strength on the healing of the abdominal wall of rats treated with infliximab

PURPOSE: To evaluate the effects of infliximab, a murine/human chimeric monoclonal antibody, on the tensile strength of abdominal wall surgical wounds. METHODS: Sixty Wistar healthy male rats with initial body weight between 215 and 390 g and 60 and 90 days of age were randomly assigned into two groups, E (Experimental) and C (Control) with 30 animals each. Group E animals received a single subcutaneous dose of 5mg/Kg of infliximab, and Group C animals received equivalent subcutaneous volume of a solution of 0.9% NaCl. After 48h, animals from both groups were submitted to a 4 cm median incision in the abdominal wall, including all layers that had been reconstituted with continuous suture of the aponeurotic muscle and skin, with 5.0 nylon thread. Then, Group E animals were separated by simple allotment into three subgroups named E3, E7 and E14 with ten animals each, and those from group C into C3, C7, C14 and were submitted, respectively, the reoperation and euthanasia at the third, seventh and fourteenth postoperative day. The anterior abdominal wall, which was resected during reoperation, was cut with No 15 scalpel lamina perpendicularly to the surgical wound. Each specimen, in the form of a 6 cm x 2 cm strip, was fixed by the extremity so that the suture line was equidistant from the fixation points of the dynamometer, in order to undergo the tensile strength test. The dynamometer, which was gauged for each series of measures, was calibrated to apply velocity to the 25 mm/min rupture test; the rupture value was expressed in N (Newton). Prior to euthanasia, the abdominal vena cava was identified and punctured in order to collect blood for TNF-α dosage. RESULTS: The mean tensile strength found for animals from subgroups E3, E7, E14, C3, C7, C14 were, respectively, 16.03, 18.69, 27.01, 28.40, 27.22, 29.15 and 24.30 N. In the results of the multiple comparisons tests, significant differences (p<0.05) was found between subgroups E3 and E7 compared with C3, C7 and C14. CONCLUSION: The infliximab interfered in the healing of the abdominal wall wound decreasing the rupture strength in the inflammatory and proliferative phases.

Effects of enoxaparin on the healing of abdominal wall in rats: study on breaking strength and histopatology

PURPOSE: To evaluate the influence of enoxaparin on the abdominal wall healing. METHODS: Sixty Wistar male rats were randomly distributed into two experimental groups. Group E: consisted of 30 rats, submitted to abdominal suture and treated with enoxaparin in a dose of 1 mg/kg of body weight, subcutaneously administered from immediate postoperative until the 7th day; Group C: consisted of 30 rats submitted to abdominal suture and treated with the equivalent dose per volume of NaCl 0.9%. The animals were submitted to median laparotomy and were operated again at the 3rd, 7th or 14th postoperative day for the resection of the anterior abdominal wall. The tissue's stretching resistance was tested and a histopathological evaluation was performed. Through Mann-Whitney's U test, a statistical analysis was conducted considering significant values for p <0.05. RESULTS: The tensile breaking strength presented a median of 0.64N for group C and 0.41N for group E (p=0.60) at the 3rd postoperative day; of 2.27N for group C and of 4.32N for group E (p=0.01) at the 7th POD; of 5.72N for group C and of 6.62N for group E (p=0.97) at the 14th POD. In relation to the histopathological study, the results did not show significant statistical differences, except for the amount of collagen at the 7th POD, which medians were 2 on group C and 1 on group E (p=0.007). CONCLUSION: Considering the conditions in which this study was conducted, the administration of enoxaparin led to an strengthening of the tissue's breaking resistance at the 7th POD; on the histopathological exam, a significant difference was observed at the 7th POD, with a better collagen disposition on group C.

Selective cyclo-oxygenase 2 inhibition affects ileal but not colonic anastomotic healing in the early postoperative period

BACKGROUND

Selective cyclo-oxygenase 2 (COX-2) inhibitors are increasingly prescribed in the perioperative period. Recent recognition of a possible role for COX-2 in wound healing has raised concerns about the safety of their use in surgical practice. Therefore, the influence of celecoxib, a selective COX-2 inhibitor, on early anastomotic healing was investigated.

METHODS

Celecoxib, in doses of 15, 50 or 200 mg per kg per day, was given daily from the day before operation onwards to male Wistar rats that received both ileal and colonic anastomoses. Anastomotic strength was assessed by measuring the breaking strength and bursting pressure on the third day after operation. A second group received a dose of 50 mg per kg per day and a colonic anastomosis only, and healing was assessed on the third and fifth day after surgery.

RESULTS

Expression of COX-2 protein was upregulated in the anastomotic area. Administration of celecoxib, at all doses tested, resulted in a significantly higher ileal dehiscence rate than in control rats (P = 0.002). In contrast, colonic anastomoses healed normally within the same animals. The latter was confirmed in rats with colonic anastomoses only.

CONCLUSION

In this model, administration of the COX-2 inhibitor celecoxib affected ileal but not colonic anastomotic healing in the early postoperative period.

Clinical review: Healing in gastrointestinal anastomoses, Part I

Gastrointestinal healing is a topic rarely reviewed in the literature, yet it is of paramount importance to the surgeon. Failure of anastomotic healing may lead to life-threatening complications, additional surgical procedures, increased length of stay, increased cost, long-term disability, and reduced quality of life for the patient. The goal of this article is to review the biological response to wounded tissue, to outline discrete differences between skin and gastrointestinal healing, to discuss local and systemic factors important to gastrointestinal healing, and to compare methods of measuring collagen content and strength of the newly formed anastomosis. Part II of this review will focus on techniques and therapies available to optimize anastomotic healing.

Extrato de Passiflora edulis na cicatrização de anastomose colônica em ratos: estudo morfológico e tensiométrico

INTRODUÇÃO: Pesquisas de novas substâncias com finalidades terapêuticas têm sido realizadas procurando isolar, extrair ou purificar novos compostos de origem vegetal. A Passiflora edulis (maracujá), espécie pertencente à família Passifloracea, originária das regiões tropicais e subtropicais do continente americano, é popularmente usada como sedativo, analgésico e antinflamatório e no tratamento de lesões cutâneas, feridas e erisipelas. OBJETIVO: Avaliar a cicatrização de anastomoses colônicas em ratos, que receberam extrato hidroalcoólico de Passiflora edulis no trans-operatório. MÉTODOS: Foram utilizados 40 ratos Wistar, distribuídos em dois grupos de 20 animais cada, denominados: grupo Passiflora (GP) e grupo controle (GC). Os ratos de cada grupo foram separados em dois subgrupos de 10 animais cada, avaliados no 3º e 7º dia do pós-operatório. O procedimento cirúrgico constou de secção da alça colônica esquerda, 5cm acima da reflexão peritoneal com preservação da arcada vascular e anastomose término-terminal em plano único. O grupo Passiflora recebeu dose única intraperitoneal do extrato hidroalcoólico de Passiflora edulis na dose de 250 mg/Kg. O grupo controle recebeu dose única de solução salina intraperitoneal em volume igual ao GP. Os parâmetros avaliados foram: aspectos macroscópicos da parede e cavidade abdominal, aderências perianastomóticas, pressão de ruptura à insuflação de ar, reação inflamatória tecidual da anastomose que constou de polimorfonucleares, monomorfonucleares e proliferação fibroblástica. RESULTADOS: Os aspectos macroscópicos não apresentaram diferenças significantes entre os grupos. Não ocorreu nenhuma deiscência de anastomose nos grupos estudados. Com relação à pressão de ruptura à insuflação de ar, observou-se que a média foi significantemente maior no subgrupo que recebeu o extrato de Passiflora no 3º dia (P3), cuja pressão foi 42,6 ± 17,8 mmHg em comparação ao subgrupo controle (C3), cuja pressão foi 25,4 ± 14,1 mmHg, p=0,028. O mesmo não ocorreu no 7º dia, onde o subgrupo C7 apresentou pressão de ruptura de 187,3 ± 39,5 mmHg, enquanto o subgrupo P7, apresentou pressão de ruptura de 203,0 ± 50,0 mmHg, p=0,447. Na análise histológica, os polimorfonucleares foram mais freqüentes no subgrupo C3, em comparação ao subgrupo P3, com diferença significante (p=0,034). Os monomorfonucleares (MMN) e proliferação fibroblástica foram mais freqüentes no subgrupo P3, com diferença significante, onde p=0,02 para MMN, e p=0,001 para proliferação fibroblástica. No 7º dia, houve diferença significante em todas as variáveis histológicas coradas pela hematoxilina-eosina e Tricômico de Masson (p<0,05) no subgrupo que recebeu o extrato de Passiflora. CONCLUSÃO: A administração peroperatória do extrato hidroalcoólico de Passiflora edulis influencia de forma significante na cicatrização das anastomoses colônicas em ratos.

Misoprostol therapeutics revisited

Misoprostol, a prostaglandin E1 analog, is a racemate of four stereoisomers. On administration it rapidly de-esterifies to its active form, misoprostolic acid. Misoprostolic acid is 85% albumin bound and has a half-life of approximately 30 minutes. It is excreted in urine as inactive metabolites. No significant drug interactions have been reported. Besides its gastrointestinal protective and uterotonic activities, misoprostol regulates various immunologic cascades. It inhibits platelet-activating factor and leukocyte adherence, and modulates adhesion molecule expression. It protects against gut irradiation injury, experimental gastric cancer, enteropathy, and constipation. It improves nutrient absorption in cystic fibrosis. Misoprostol has utility in acetaminophen and ethanol hepatotoxicity, hepatitis, and fibrosis. It is effective in asthmatics and aspirin-sensitive asthmatic and allergic patients. It lowers cholesterol and severity of peripheral vascular diseases, prolongs survival of cardiac and kidney transplantation, synergizes cyclosporine, and protects against cyclosporine-induced renal damage. It works against drug-induced renal damage, interstitial cystitis, lupus nephritis, and hepatorenal syndrome. It is useful in periodontal disease and dental repair. Misoprostol enhances glycosoaminoglycan synthesis in cartilage after injury. It prevents ultraviolet-induced cataracts and reduces intraocular pressure in glaucoma and ocular hypertension. It synergizes antiinflammatory and analgesic effects of diclofenac or colchicine and has been administered to treat trigeminal neuralgic pain. It reduces chemotherapy-induced hair loss and recovery time from burn injury, and is effective in treating sepsis, multiple sclerosis, and pancreatitis.

Healing in the gastrointestinal tract

Healing in the GI tract is rapid when free of complications: Unlike cutaneous healing, in which progress can be observed on a daily basis and intervention instituted early if necessary, healing of the intestinal anastomosis is anatomically obscured from inspection, allowing the surgeon only the patient's parameters of general well-being to judge the success of the operation. For the same reason, complications usually require re-operation, with the associated morbidity of a laparotomy and additional general anesthetic. This places a great responsibility on the surgeon to be cognizant of all the preoperative, intraoperative, and postoperative factors relating to anastomotic healing that might compromise the healing process. Bearing these in mind, along with attention to technical detail, should limit complications to an acceptable level. Patients most at risk are (1) those who perioperatively develop physiologic problems that lead to shock, hypoxia, and resultant anastomotic ischemia, (2) those with radiation-induced tissue injury, (3) those with sepsis, and (4) those with preoperative bowel obstruction. Malnourishment, malignancy, diabetes, steroids, and age also influence outcome to varying degrees. Future advancement in the field of GI healing lies in our ability to manipulate the early struggle between collagen synthesis and collagen breakdown. A profound understanding of the molecular and biochemical pathways and the factors that control them will bring us closer to this goal. Clinically, this may be accomplished by the introduction of wound healing enhancers into the anastomotic site, possibly by incorporating them into suture materials, biofragmentable anastomotic rings, or staple materials. Already much is known about the influence of different cytokines and growth factors on collagen regulation, knowledge that will help resolve many of the long-standing problems associated with GI surgery.