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.     

The effect of parenteral nutrition on the healing of abdominal wall wounds and colonic anastomoses in protein-malnourished rats

The effect of postoperative parenteral nutrition on the healing of abdominal wall wounds and colonic anastomoses in protein-malnourished rats was studied. The healing of laparotomy wounds and colonic anastomoses was assessed by bursting pressure measurement on the fifth postoperative day. Compared with control animals on a normal diet (group A), rats on a low-protein diet given postoperative dextrose-saline solution (group B) had significantly lower abdominal wall and colonic anastomotic bursting strengths. The detrimental effects of protein malnutrition could be completely reversed for abdominal wall wounds and partially reversed for colonic anastomoses in rats on a low-protein diet given postoperative parenteral nutrition (group C). Autoradiographic studies showed a marked decrease in the activity of wound fibroblasts that was restored by the administration of postoperative parenteral nutrition. Serum protein measurements showed a closer correlation of colonic anastomotic healing to serum albumin than to serum transferrin values but showed no correlation with abdominal wall wound healing.     

Histoacryl blue versus sutured left colonic anastomosis: experimental study

BACKGROUND: Cyanoacrylates have been advocated as a protective seal in colonic anastomosis to prevent leakage. In order to assess the effects of n-butyl-2-cyanoacrylate on left colonic anastomosis it was compared to the sutured anastomosis in the rat. METHODS: Forty male Wistar albino rats were divided into two groups of 20 each. On days 3 and 7, 10 animals in each group were killed. The comparisons between n-butyl-2-cyanoacrylate and sutured groups were made with respect to outcome measures including anastomotic leakage, anastomotic stricture, peritonitis and wound infections, and adhesion formation, anastomotic bursting pressure, histological appearance of the anastomotic area. RESULTS: Although the adhesion formation was significantly more extensive in the n-butyl-2-cyanoacrylate group on day 3 (P < 0.001), there was no significant difference between the groups on day 7. The more inflammatory reaction also occurred in the n-butyl-2-cyanoacrylate group. The mean +/- SD anastomotic bursting pressure was significantly higher in the suture group than in the n-butyl-2-cyanoacrylate group (63 +/- 14 mmHg vs 43 +/- 8 mmHg) on day 3. The bursting pressure was also found to be higher on day 7 in the suture group (187 +/- 26 mmHg vs 49 +/- 12 mmHg, P < 0.0001). The suture group had a significantly higher bursting pressure on day 7 compared to day 3 (P < 0.05). CONCLUSIONS: Left colonic anastomosis with n-butyl-2-cyanoacrylate in rats does not improve the healing process; on the contrary, it has a negative influence during the first week. As a consequence, the routine use of n-butyl-2-cyanoacrylate in colonic anastomosis in the clinical situation does not appear to be justifiable.     

Experimental study of the influence of intestinal flora on the healing of intestinal anastomoses.

BACKGROUND: The beneficial effects of the normal intestinal flora on wound healing in the skin have already been confirmed, and this study attempted to elucidate the influence of the intestinal flora on the healing process in intestinal anastomoses. METHODS: Five groups of rats were studied: germ-free, conventional, monocontaminated with Lactobacillus acidophilus La5 or Escherichia coli X7 and ex-germ-free (conventionalized). All animals underwent ileal and colonic resections followed by anastomoses. Seven days later they were killed and the bursting pressure and hydroxyproline concentration of the anastomoses were measured. The microbiological status of the animals was confirmed weekly. RESULTS: No bacteria were detected in the germ-free rats and no other bacteria were found in the monocontaminated animals. Conventional rats had a significantly higher anastomotic bursting pressure both in the ileum compared with rats monocontaminated with L. acidophilus, and in the colon compared with germ-free rats. The ex-germ-free rats also showed a significantly higher bursting pressure than germ-free animals and rats monocontaminated with either L. acidophilus or E. coli in the ileum and colon. CONCLUSION: The presence of the intestinal flora enhanced the healing of intestinal anastomoses. The data suggest that this effect depends on differences in the types of bacteria in the intestine.     

Locally applied molgramostim improves wound healing at colonic anastomoses in rats after ligation of the common bile duct.

BACKGROUND: Several systemic factors, including jaundice, long-term corticosteroid therapy, diabetes and malnutrition, increase the risk of anastomotic dehiscence. The local application of molgramostim (recombinant human granulocyte-macrophage colony stimulating factor) has been reported to improve impaired dermal wound healing. Since jaundice, one of the systemic risk factors for anastomotic dehiscence, causes significant impairment of anastomotic healing, we hypothesized that locally injected molgramostim could improve the healing of bowel anastomoses in bile-duct-ligated rats used as an experimental model for jaundice. METHODS: Eighty-six Sprague-Dawley rats were randomized into 4 groups of 20-22 animals each as follows: group 1--colonic anastomosis only; group 2--laparotomy followed 7 days later by colonic anastomosis; group 3--common-bile-duct ligation (CBDL) followed 7 days later by colonic anastomosis (control group); group 4--CBDL followed by colonic anastomosis with locally applied molgramostim. Laparotomy was performed under anesthesia in group 2 rats. In groups 3 and 4, laparotomy was followed by ligation and dissection of the common bile duct. After 7 days, colonic anastomosis was performed; in group 4 rats, molgramostim (50 microg) was injected into the perianastomotic area. On postoperative day 3, rats were killed, and the bursting pressures and hydroxyproline levels measured. Two rats from each group were selected for histopathological examination. RESULTS: The mean bursting pressure in group 4 was significantly higher than that in group 3 (37.8 v. 30.5 mm Hg [p < 0.01]). The mean hydroxyproline level in group 3 was significantly lower than that of the other groups (2.7 v. 3.1-3.5 mg/g tissue [p < 0.01]). On histopathological examination, specimens from group 4 rats showed an increased mononuclear cell population and a smaller gap on the anastomotic line than those from group 3. CONCLUSION: The local injection of molgramostim improves healing of the impaired wound in rats subjected to CBDL.     

Activated protein C prevents deleterious effects of remote reperfusion injury caused by intestinal ischemia on wound healing in the left colonic anastomoses: an experimental study in the murine model

Background

Activated protein C (APC) is a serine protease with anticoagulant and antiinflammatory activities. The delaying effects of remote reperfusion injury on the wound-healing process in colonic anastomoses have been previously shown. In this study, we aimed to investigate whether APC protects against deleterious systemic effects of intestinal ischemia/reperfusion (I/R) injury on colonic anastomotic wound healing process.

Methods

Male Wistar-albino rats were randomly allocated into 4 groups, and a left colonic anastomosis was performed in all animals: (1) sham-operated group, simultaneously with left colonic anastomosis, the superior mesenteric artery and collateral branches were divided from the celiac axis, and the inferior mesenteric artery were isolated but not occluded (group 1, n = 12), (2) sham + APC group, identical to group 1 except for APC treatment (100 μg/kg, intravenously, 15 minutes before construction of the colonic anastomosis), (group 2, n = 12), (3) intestinal I/R group, 60 minutes of superior mesenteric ischemia followed by reperfusion (group 3, n = 12), and (4) APC-treated group, (100 μg/kg, intravenously, 15 minutes before reperfusion) (group 4, n = 12). All animals were sacrificed, and colonic anastomotic bursting pressures were measured in vivo on day 7. Tissue samples were obtained for analysis of hydroxyproline contents, nitrate/nitrite levels, and activities of oxidative and antioxidative enzymes. The plasma levels of proinflammatory cytokines and D-dimer were also measured.

Results

Intestinal I/R led to significant decreases in colonic anastomotic bursting pressures, tissue hydroxyproline contents, and activities of antioxidative enzymes, along with increases in tissue nitrate/nitrite levels, activities of oxidative enzymes, and plasma levels of proinflammatory cytokines and D-dimer (P < .05). However, APC treatment led to significant increases in colonic anastomotic bursting pressures, tissue hydroxyproline contents, and activities of antioxidative enzymes, along with decreases in tissue nitrate/nitrite levels, activities of oxidative enzymes, and plasma levels of proinflammatory cytokines and D-dimer (P < .05).

Conclusion

This study clearly showed that APC treatment prevented the delaying effects of remote I/R injury on colonic anastomotic wound healing process. Further clinical studies are required to determine whether APC has a useful role in the enhancement of colonic anastomotic wound healing after particular operations in which I/R injury occurs.     

Effects of a membrane-permeable radical scavenger, Tempol, on healing of colonic anastomoses in the cecal ligation and puncture model of polymicrobial sepsis in rats

BACKGROUND: Tempol (Sigma-Aldrich, Steinheim, Germany) is a stable piperidine nitroxide of low molecular weight that permeates biologic membranes and scavenges superoxide anions in vitro. In recent animal studies, the delaying effect of intraperitoneal sepsis on the healing of colonic anastomoses has been shown. In this study we aimed to investigate the effects of Tempol on the healing of colonic anastomoses in the presence of polymicrobial sepsis. METHODS: Anastomosis of the left colon was performed on the day after cecal ligation and puncture (CLP) in 30 rats that were divided into 3 groups: sham-operated control (laparotomy and cecal mobilization, group I, n = 10), CLP (group II, n = 10), Tempol-treated group (30 mg/kg intravenously before the construction of colonic anastomosis, group III, n = 10). On postoperative day 6, all animals were killed and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, malondialdehyde (MDA), and glutathione (GSH) levels. RESULTS: There was a statistically significant increase in MPO activity and MDA levels in the CLP group (group II), along with a decrease in GSH levels, anastomotic HP contents, and bursting pressure values when compared with controls (group I). However, Tempol treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP contents, and GSH levels, along with a decrease in MPO activity and MDA levels in group III (P < .05). CONCLUSIONS: This study showed that Tempol treatment significantly prevented the delaying effect of CLP-induced polymicrobial sepsis on anastomotic healing in the left colon. Further clinical studies are needed to clarify whether Tempol may be a useful therapeutic agent to increase the safety of the anastomosis during particular surgeries in which sepsis-induced organ injury occurs.     

Evaluation of anastomotic strength and drug safety after short-term sunitinib administration in rabbits

Background

Sunitinib (Sutent) is a Food and Drug Administration–approved receptor tyrosine kinase inhibitor found to reduce postoperative adhesion formation in animal models. The objective of the present study was to evaluate anastomotic healing and potential drug-related toxicities after short-term sunitinib administration in New Zealand White rabbits.

Materials and methods

Under an approved study protocol, 40 rabbits underwent a laparotomy followed by colonic transection and anastomosis. Animals were randomly assigned to treatment with oral sunitinib (10 mg/kg/d) or placebo, received one preoperative dose followed by 10 postoperative doses, and were divided into two groups following the procedure: group I animals were euthanized on completion of drug treatment and group II animals were euthanized 30 d after completion of treatment. Prior to study completion, animals underwent an echocardiogram and laboratory test results were obtained. At necropsy, intestinal bursting strength (in mmHg) was evaluated.

Results

All animals survived until designated euthanasia. There was no evidence of intra-abdominal sepsis or intestinal obstruction. Sunitinib-treated animals were found to have lower intestinal anastomotic strength compared with placebo-treated animals, as measured by bursting pressure at euthanasia, and a greater percentage of bursting at the anastomosis. On echocardiography, all ejection and shortening fractions were within established normal reference values. There were no significant differences in liver enzymes between animals. There were no wound infections, dehiscence, or delayed wound healing in any animal.

Conclusions

These results caution against the administration of sunitinib in cases involving intestinal anastomoses because of the elevated risk of anastomotic leak. No evidence of cardiotoxicity, hepatotoxicity, or detrimental effect on wound healing was found in any animal.     

Benign Mucinous Cystadenoma of the Appendix Report of 3 Cases. Review of the Literature

Backgrounds/Aims: Inflammation during the early phase of anastomotic wound healing is an essential cellular response and is suppressed by corticosteroids. The anti-inflammatory effect of corticosteroids is largely responsible for its impairment of wound healing in bowel anastomosis. Beta-D-glucan, a commonly used macrophage activator, has been shown to improve anastomotic wound healing under normal conditions. In the present study, we have investigated the effects of beta-D-glucan on anastomotic wound healing in rats treated with long-term corticosteroid. Methodology: 92 male Sprague-Dawley rats were randomized into four groups. 1: control, 2: control + beta-D-glu-can, 3: steroid, 4: steroid + beta-D-glucan. Methylprednisolone (5mg/kg) was injected IM daily for 14 days in groups 3 and 4. After 14 days, following anaesthesia and laparotomy, colonic anastomosis was performed 3 cm away from the peritoneal reflection of rectum. In groups 2 and 4, 100mg/kg beta-D-glucan was administered orally for 7 days before laparotomy. On postoperative day 3, relaparotomies were performed and bursting pressures, hydroxyproline levels and histopathological specimens were studied.

Results: The mean values of bursting pressures groups were 50.8 (95% CI 46.99-56.50), 58.2 (95% CI 54.49-61.90), 32.0 (95% CI 29.21-34.98), 45.9 (95% CI 43.09-48.80) respectively. The differences of the mean values of the groups between group 1 and 2 and also 3 were significant (p = 0.002, p < 0.001). The mean values of hydroxyproline of the groups were 3.8 (95% CI 3.56-4.06), 4.7 (95% CI 4.50-5.04), 2.9 (95% CI 2.73-3.20), 3.9 (95% CI 3.65-4.22) respectively. The differences of the values of the groups between control (group1) and group 2 and also group 3 were significant (p = 0.001, p < 0.001). In histopathological examination, increased macrophages and fibroblast population were observed in specimens from beta-D-glucan-treated animals.

Conclusion: The results indicate that in rat model, oral administration of beta-D-glucan causes a significant improvement in the healing of anastomotic wound impaired by long-term corticosteroid administration.     

Insulin-like growth factor I and truncated keratinocyte growth factor accelerate healing of left-sided colonic anastomoses

BACKGROUND: Human full-length keratinocyte growth factor (KGF) promotes healing of colon anastomoses in rats through mechanisms other than enhancement of collagen synthesis. Since insulin-like growth factor (IGF) I increases matrix synthesis, the aim of this study was to evaluate the effect of systemic truncated KGF (tKGF), IGF-I and combined tKGF-IGF-I administration on the healing of colonic anastomoses in rats. METHODS: Rats underwent laparotomy, division of the left colon, and sigmoidosigmoidostomy. tKGF (1 mg/kg), IGF-I (1 mg/kg), tKGF-IGF-I (both 1 mg/kg) or vehicle was administered intraperitoneally in four groups (n = 18 per group) 12 h before surgical intervention, and then once daily until killing (six animals per group; 2, 4 and 6 days after surgery). Bursting pressure measurements, histological evaluation, morphometric analysis, mucin and collagen staining, and 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry of the anastomotic site were undertaken. RESULTS: Administration of tKGF, IGF-I and the combination of both growth factors significantly increased anastomotic bursting pressure at postoperative day 2 (63, 71 and 113 per cent respectively), day 4 (68, 83 and 80 per cent) and day 6 (48, 43 and 43 per cent) compared with the control group. No intergroup differences were found. Histological examination, mucin and BrdU staining, and measurement of colonic crypt depth indicated less inflammation, increased acidic mucin content, a higher crypt cell proliferation rate and thickened mucosal layer in the growth factor-treated animals than in controls. Enhanced collagen staining was observed only in IGF-treated animals. CONCLUSION: tKGF and IGF-I markedly accelerate the healing of colonic anastomoses in rats. However, combined administration of the two growth factors does not show additional benefit. Both growth factors may be acting to accelerate host reparative processes as well as to enhance protection of the anastomotic wound bed.     

Neoadjuvant antiangiogenic therapy with tamoxifen does not impair gastrointestinal anastomotic repair in the rat

Introduction Antiangiogenic therapy has the potential to moderate tumour and micrometastatic growth. Its use in the perioperative period is attractive but its potential to compromise wound and anastomotic healing is a cause for concern. Tamoxifen is antiangiogenic but also favourably modifies some aspects of wound healing. We hypothesised that tamoxifen would not adversely affect skin wound and gut anastomotic healing. Methods A previously established model of tamoxifen, administered orally at antiangiogenic doses (20 mg/ml arachais oil/day), was used. Animals received two days pretreatment prior to laparotomy and small bowel anastomosis. Treatment was continued until completion of the study. The principal outcome measures are survival, macroscopic wound and anastomotic healing, anastomotic bursting pressure and PVA sponge granuloma hydroxyproline (OHP) content. Results Tamoxifen treated animals had fewer complications of skin wound healing than controls (4.5%vs. 19.5%; χ² 4.65, 1 d.f., P < 0.05). There was no significant difference in adhesion formation or macroscopic complications of anastomotic healing. Anastomotic bursting pressure was greater in tamoxifen treated animals at postoperative day 3 (39 ± 4.4 vs. 22.5 ± 3.5 mmHg; P < 0.01) and equal to that of controls on postoperative day 5 (144.4 ± 9.4 vs. 127.3 ± 10.9 mmHg; P = ns). Tamoxifen treated animals weighed significantly less than placebo controls from postoperative day 3 with no difference in mortality between groups (χ² = 0.06, 1df, P = ns). PVA sponge granuloma OHP content on day 7 was higher in tamoxifen‐treated animals (2.93 ± 0.4 vs. 1.4 ± 0.4 mg OHP/mg dry sponge weight; P = 0.03). Conclusion Antiangiogenic therapy with tamoxifen has no demonstrable adverse effects on wound or anastomotic repair and its perioperative use is compatible with successful early surgical outcomes.     

Effect of matrix metalloproteinase inhibition on colonic anastomotic healing in rats

Wound strength depends on the balance between collagen synthesis and degradation; however, the role of collagen breakdown in wound healing is still not well understood. We investigated the role of matrix metalloproteinases in wound healing by using BE16627B, a matrix metalloproteinase inhibitor. Identical surgical procedures consisting of a colonic anastomosis (single-layer, inverted) and implantation of an osmotic pump in the back were performed in male Sprague-Dawley rats weighing 270 to 290 grams. The animals were randomly assigned to receive either BE16627B (n = 10) dissolved in dimethylsulfoxide and diluted with ethylene glycol at a dosage of 2.4 mg/rat/day for 3 days or the vehicle solution alone (n = 11). The solutions were administered through the surgically implanted osmotic pumps. The animals were killed 4 days after surgery, and the colonic bursting pressure (mm Hg) and hydroxyproline concentration (μg/mg wet tissue, index of collagen) were measured. The administration of BE16627B enhanced colonic anastomotic healing, as measured by the increase in the colonic bursting pressure (160 ±12 vs. 125 ±7 mm Hg; P <0.05) and the increase in the soluble fraction of collagen (0.27 ± 0.01 vs. 0.21 ± 0.01 μg/mg wet tissue; P <0.01) in the anastomosis. Histologic examination of the tissue revealed that the use of BE 1662 7B resulted in the preservation of the multilayered colonic structure and increased the network of collagen between both ends of the colon in the thickening submucosal layer. These findings demonstrate that the inhibition of matrix metalloproteinase activity influences colonic anastomotic healing, indicating a potential mechanism for enhancing anastomotic healing. Supported by a Grant-in-Aid for Scientific Research (C) from the Japan Society for the Promotion of Science. Presented at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 21–24, 2000.     

Effects of Pyrrolidine Dithiocarbamate on Healing of Colonic Anastomoses in the Cecal Ligation and Puncture Model of Intraperitoneal Sepsis in Rats

Introduction Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. In recent animal studies, the delaying effect of intraperitoneal sepsis on healing of colonic anastomoses has been demonstrated. In this study, we aimed to investigate the effects of PDTC on healing of colonic anastomoses in the presence of intraperitoneal sepsis induced by a rodent model of cecal ligation and puncture (CLP). Methods Anastomosis of the left colon was performed on the day following CLP in 30 rats that were divided into three groups: sham-operated control (laparotomy and cecal mobilization, group I, n =10), cecal ligation and puncture (CLP) (group II, n = 10), PDTC-treated group (100 mg/kg IV before construction of the colonic anastomosis) (group III, n = 10). On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of colonic anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, and malondialdehyde (MDA) and glutathione (GSH) levels. Results There was a statistically significant increase in the activity of MPO and MDA levels in the CLP group (group II) along with a decrease in GSH levels, colonic anastomotic HP contents, and bursting pressure values when compared to controls (group I). However, PDTC treatment led to a statistically significant increase in the tissue HP contents, GSH levels, and colonic anastomotic bursting pressure values, along with a decrease in MPO activity and MDA levels in group III (p < 0.05). Conclusions This study showed that PDTC treatment significantly prevented the delaying effect of CLP-induced intraperitoneal sepsis on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to increase the safety of the anastomosis during particular operations where sepsis-induced injury occurs.     

Locally applied granulocyte-macrophage colony-stimulating factor improves the impaired bowel anastomoses in rats with long-term corticosteroid treatment

Inflammation is an essential component of the first phase of anastomotic wound healing, and it is suppressed by corticosteroids. The anti-inflammatory effect of corticosteroids is largely responsible for the impairment of wound healing in bowel anastomosis. It has been reported that local application of granulocyte-macrophage colony-stimulating factor (GM-CSF) improves the healing process in dermal wounds. In the present study, we investigated the effects of locally injected GM-CSF on anastomotic wound healing in long-term corticosteroid treated rats. Eighty male Sprague-Dawley rats were randomized into four groups. (1) control, (2) steroid, (3) steroid + local GM-CSF, (4) steroid + systemic GM-CSF. In groups 2, 3, and 4, methylprednisolone (5 mg/kg) was injected IM daily for 14 days. After 14 days, following anesthesia and laparotomy, colonic anastomosis was performed 3 cm away from the peritoneal reflection. In group 3, 50 mg GM-CSF was injected into the perianastomotic area. In group 4, 50 mg GM-CSF was applied subcutaneously. On postoperative day 3, repeat laparotomies were performed and bursting pressures, hydroxyproline levels, and histopathology examinations were studied. The mean values of bursting pressures and hydroxyproline levels in group 3, treated with steroid + local GM-CSF, were significantly higher than that of the group 2 and group 4 values. In the histopathology examination, the mean score of group 3 was significantly higher than that of groups 2 and 4. Our study indicates that local application of GM-CSF significantly improves the impaired anastomotic wound healing in rats treated with long-term corticosteroid.     

Differential effect of tacrolimus on dermal and intestinal wound healing.

Tacrolimus, used in organ transplantation, inhibits cellular immune function. Little is known about the effect on dermal and colonic healing. Groups of 10 rats underwent dorsal skin incision, and polyvinyl alcohol sponges were implanted subcutaneously. Beginning at the day of wounding, rats were treated intraperitoneal with 1.0 or 2.0 mg tacrolimus/kg/day. Animals were sacrificed 10 d later to determine wound breaking strength and reparative collagen deposition. Expression of transforming growth factor (TGF)-beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma was studied in wounds. Groups of 8 rats underwent laparotomy and left colonic anastomosis. These rats were treated by subcutaneous injections with 2.0 or 5.0 mg tacrolimus/kg. Animals were sacrificed 5 d later to test colonic bursting pressure and reparative collagen deposition. Expression of TGF-beta, TNF-alpha, IFN-gamma, and CD4 and CD8 in the anastomosis was investigated. Tacrolimus impaired dermal healing (p < .05). This was paralleled by decreased expression of TGF-beta (stimulates healing) and increased expression of IFN-gamma and TNF-alpha (both inhibit healing) (p < .05). In contrast, tacrolimus did not inhibit healing of colonic anastomoses. No effect was seen on the expression of TGF-beta, TNF-alpha, IFN-gamma, and CD4 and CD8 in colonic anastomoses. We concluded that tacrolimus differentially effects tissue healing and expression of cellular mediators in dermal and intestinal wounds.     

Doxycycline improves wound strength after intestinal anastomosis in the rat

BACKGROUND: The strength of intestinal anastomoses is relatively low in the first days after operation, possibly as a result of localized degradation of the supporting matrix by enzymes from the matrix metalloproteinase (MMP) family. The aim of this study was to examine whether doxycycline, a drug known to inhibit MMP activity, could enhance anastomotic strength. METHODS: Male Wistar rats received anastomoses in both ileum and colon. From the day before operation onwards, animals were treated daily with doxycycline (orally or subcutaneously) in a dose of 10 mg/day or with saline only. Rats were killed 1, 3, or 5 days after operation, and anastomotic bursting pressure and breaking strength were measured. At day 3, anastomotic hydroxyproline levels were measured, MMP (gelatinase) activity was analyzed by gelatin zymography, and anastomotic histology was examined. RESULTS: Doxycycline enhanced wound strength, but only at day 3, when it was at its lowest. Subcutaneous administration of 10 mg/day increased median colonic and ileal breaking strength by 27% (P =.0019) and 104% (P =.0376), respectively. Colonic bursting pressure was increased by 93% (P =.0002). Wound histology was similar in experimental and control groups. CONCLUSIONS: Administration of doxycycline enhances anastomotic strength and should be investigated further as a means to preserve anastomotic integrity.     

Prevention of intra-abdominal adhesions using the antiangiogenic COX-2 inhibitor celecoxib

OBJECTIVE: To determine the effects of COX-2 specific inhibitors on postoperative adhesion formation. SUMMARY AND BACKGROUND DATA: Intra-abdominal adhesions are the major cause of intestinal obstruction and secondary infertility after surgical procedures. Because adhesion synthesis requires angiogenesis, and cyclooxygenase-2 enzyme (COX-2) inhibitors have antiendothelial activity, we tested COX-2 inhibitors in a murine model of intra-abdominal adhesion formation. METHODS: A silicone patch was secured to the lateral abdominal wall of groups of C57BL/6 mice, followed by cecal abrasion to promote adhesion formation. Beginning on the day of surgery, mice were treated with the selective COX-2 agents, celecoxib or rofecoxib, and the nonspecific COX inhibitors, aspirin, naproxen, ibuprofen, or indomethacin. Animals were treated for 10 days and killed. A second group (celecoxib, rofecoxib, aspirin) was treated for 10 days and observed for an additional 25 days. After treatment, intra-abdominal adhesions were scored using a standard method. The patch was subjected to immunohistochemistry with the endothelial-specific marker, CD31. RESULTS: Animals treated with selective and nonselective COX-2 inhibitors, except aspirin, had significantly fewer adhesions than control animals. Celecoxib produced a maximal reduction in adhesion formation compared with rofecoxib and the nonselective COX-2 inhibitors at 10 days. After 25 days, celecoxib and rofecoxib, but not aspirin, had fewer adhesions than control mice. Adhesions from mice treated with celecoxib had reduced microvessel density compared with rofecoxib, the nonselective COX inhibitors, and control animals. CONCLUSIONS: Selective COX-2 inhibitors, in particular celecoxib, provide durable inhibition of intra-abdominal adhesions through an antiangiogenic mechanism.     

Influence of intraperitoneal phospholipid dosage on adhesion formation and wound healing at different intervals after surgery

BACKGROUND: Adjuvant therapy is needed to prevent adhesion formation as a major cause of postoperative morbidity and mortality. The efficacy of phospholipids (PLs) has been proven; however, information on dosage and drug safety are still outstanding. MATERIALS AND METHODS: Forty-eight Chinchilla rabbits underwent median laparotomy, abrasion of the peritoneum, jejunal anastomosis, and an electrocautery incision of the liver. The operation was completed by intraperitoneal administration of PLs in two different concentrations (30 mg/kg and 70 mg/kg body weight). In the control group, the abdomen was closed without additional treatment. Adhesion area, anastomotic bursting pressure, tensile strength of the midline incision, and healing of the liver wound were assessed on days 3, 5, 7, and 10, respectively. RESULTS: The mean areas of adhesions in the control group were slightly larger than in the PL groups after 3 days and 5 days. On day 7 and day 10, both PL groups presented with significantly smaller adhesion areas (P<0.05). In all groups, we measured equal anastomotic bursting pressures on the 3rd, 5th, and 10th postoperative days. After 7 days, the mean value of the PL 70-mg group (17.2 kPa) was significantly lower than in the other groups (control 22.1 kPa, PL 30 mg 20.7 kPa; P<0.05). The tensile strengths of the laparotomy wound measured after intervals of 5 days and 7 days were not statistically different. On day 3, it was reduced after 30 mg PL but enhanced after 70 mg PL, whereas 10 days after surgery the strength increased with the PL dosage. The inflammatory reparative response to hepatic injury, jejunal anastomosis, and midline incision was not affected by PLs as assessed by histological analysis. CONCLUSION: These results prove the efficacy of PLs in adhesion prevention in two concentrations. The findings reveal an unimpeded healing of anastomoses, laparotomy wounds, and liver incisions at different periods after surgery.     

Selective cyclooxygenase-2 inhibition impairs glomerular capillary healing in experimental glomerulonephritis

Selective cyclooxygenase-2 (COX-2) inhibitors have anti-inflammatory activity and reduce proteinuria in experimental membranous glomerulonephritis. Antiangiogenic properties of COX-2 inhibitors were recently reported. Whether these properties are relevant to the glomerular healing process in inflammatory glomerular diseases was investigated. For evaluation of the effects of selective COX-2 inhibitors on the glomerular healing process in a rat model of mesangioproliferative glomerulonephritis (induced by anti-Thy 1.1 antibody), a selective COX-2 inhibitor (rofecoxib or celecoxib) or vehicle was administered daily from day 1 after disease induction until euthanasia on day 6. Additional nephritic rats were treated with rofecoxib or vehicle from day 1 to day 10 and were monitored until day 28. Selective COX-2 inhibition led to significant increases in mesangiolysis (up to +71%) on days 2 and 6 and in albuminuria (up to 3.1-fold) on day 6. This augmentation of glomerular capillary damage was associated with rarefaction of glomerular endothelial cells, whereas the proliferation and activation of mesangial cells were not affected. No significant effects on the glomerular influx of polymorphonuclear neutrophils or the infiltration and proliferation of monocytes/macrophages at day 2 were noted. These effects were independent of systemic hemodynamic features, because rofecoxib did not affect systolic BP on day 2 or 5. Nephritic rats treated with rofecoxib for 10 d demonstrated persistent glomerular injury at day 28, as indicated by increased albuminuria (10-fold) and mesangial type IV collagen deposition (+24%). In normal rats, 5-d administration of rofecoxib failed to induce albuminuria or morphologic renal damage. In conclusion, selective COX-2 inhibitors impair glomerular capillary repair after mesangiolysis in rats with anti-Thy 1.1 glomerulonephritis. These data suggest that selective COX-2 inhibitors should be used with caution among patients with inflammatory endocapillary glomerular disorders.     

The effect of an angiotensin converting enzyme inhibitor on intestinal wound healing

BACKGROUND: Dehiscence of intestinal anastomosis is associated with high mortality and morbidity rates. Angiotensin II is a potent agent in the acceleration of wound repair. Angiotensin converting enzyme (ACE) inhibitors have antifibrogenic effects. AIM: This study was performed to investigate the effect of ACE inhibitors on healing of intestinal anastomosis. MATERIALS AND METHODS: Forty-five male Wistar albino rats were divided into three groups. Ileum was divided above 10 cm from ileocecal valve after laparotomy and a single-layer ileoileal anastomosis was performed. While no treatment was given to rats in group 1, Lisinopril (an ACE inhibitor) was given to rats in group 2 and group 3 for post-operative 7 days in drinking water at 50 and 5 mg/l concentrations, respectively. Estimated amounts of supplied lisinopril were 6.5 and 0.65 mg/kg/day in groups. On post-operative 8th day, relaparotomy was performed and anastomosis-bursting pressures were measured. Then blood and tissue samples were taken for serum transforming growth factor beta-1 and tissue hydroxyproline measurements and histopathological examinations. RESULTS: High dose of lisinopril impaired the all parameters of anastomotic wound healing including bursting pressure, tissue hydoxyproline level, collagen deposition and epithelization (P < 0.001, group 2 versus groups 1 and 3). But low dose of lisinopril had no effect on those parameters (P > 0.05, group 1 versus group 3). CONCLUSION: It was concluded that lisinopril has impaired intestinal wound healing in a dose dependent manner and low doses of lisinopril can be safely used on patients with intestinal anastomosis.