The effects of iloprost on colonic anastomotic healing in rats under obstructive ileus conditions

Background

The aim of this study was to investigate the effects of iloprost, on colonic anastomotic healing in rats, under obstructive ileus conditions.

Materials and methods

Eighty male Albino rats were randomized into four groups of 20 animals each. They underwent colonic resection followed by an inverted anastomosis. The rats of group 1 (control) and group 2 (ileus) received 3 mL of saline 0.9% intraperitoneally and those of group 3 (iloprost), and group 4 (ileus + iloprost) iloprost (2 μg/kg of body weight), immediately postoperatively and daily until the day of sacrifice. Each group was further divided into two equal subgroups, depending on the day of sacrifice. The animals of subgroup “a” were sacrificed on the fourth postoperative day, whereas those of “b” on the eighth day. Macroscopic and histologic assessment was performed, whereas anastomotic bursting pressures and the tissue concentrations in hydroxyproline and collagenase I were evaluated.

Results

Means of bursting pressure, neoangiogenesis, fibroblast activity, and hydroxyproline concentration were significantly increased in group 4 compared with group 2. In addition, on the fourth postoperative day, the inflammatory cell infiltration and the collagenase I concentration were significantly decreased in group 4 compared with group 2. Moreover, on the eighth postoperative day, collagen deposition was significantly increased in group 4 compared with group 2.

Conclusions

Iloprost after intraperitoneal administration reverses the negative effect of obstructive ileus. It promotes not only the angiogenic activity but also collagen formation, resulting in increased bursting pressures on the fourth and eighth postoperative days.     

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.     

吻合口漏患者结肠组织中基质胶原代谢异常的研究

目的探讨结肠术后患者吻合口漏与结肠组织中基质胶原代谢的关系。方法通过生物化学方法测定 16例吻合口漏患者和 16例对照组患者结肠组织中基质胶原的总量并通过免疫组化分别测定基质胶原Ⅰ ,Ⅲ和基质胶原酶 1,基质胶原酶 13的含量。结果吻合口漏组结肠组织基质胶原的总量和基质胶原Ⅰ ,Ⅲ含量远低于对照组 (t=3 417,t=2 841,t =2 2 6 1,P <0 0 1)。吻合口漏组分别为 (2 2 6± 0 34 ) μg/mg ,(1 0 8± 0 2 3)p·μm2 和 (1 11± 0 2 6 )p·μm2 ,而对照组分别为 (3 33±0 41) μg/mg ,(1 6 3± 0 31)p·μm2 和 (1 39± 0 37)p·μm2 。且基质胶原Ⅰ /Ⅲ的比值吻合口漏组也低于对照组 (t=1 938,P <0 0 5 ) ,分别为 0 97± 0 2 5和 1 17± 0 2 4。吻合口漏组 16例中有 13例基质胶原酶 13阳性 ,而对照组 16例中仅 2例阳性 (χ2 =12 74,P <0 0 1)。结论吻合口漏的发生与术前结肠组织中基质胶原的数量和质量相关 ,可能与基质胶原酶 13的异常表达有关     

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.     

The effect of intraoperative colonic lavage withN G -nitro-l-arginine methyl ester (l-NAME) on anastomotic healing in the presence of left-sided colonic obstruction in the rat

-arginine methyl ester (L-NAME) on the healing of colonic anastomosis in the presence of a left-sided obstruction in the rat was investigated. Left-sided colonic obstruction was created in 144 Wistar rats. The obstruction site was excised 24 h later and anastomosis was performed after either no irrigation or colonic lavage with either saline, povidone iodine (PI), short-chain fatty acids (SCFA), L-NAME, or glutamine, in 24 animals each. Animals were killed on days 3 and 6, and a 4-cm colonic segment with the anastomosis at the center was excised. Bursting pressure (BP) and hydroxyproline (HP) content were measured. In the saline, PI, and SCFA groups, BP was higher (P < 0.05, P < 0.05, and P < 0.001, respectively) and HP concentration was similar compared with controls. Both the BP and HP concentrations were higher in the glutamine group compared with controls (P < 0.001). BP was lower (P < 0.05) and HP concentration was similar in the L-NAME group compared with the control group. Colonocyte nutrition and tissue perfusion are the mainstays of anastomotic healing. Intraoperative colonic lavage with L-NAME suppresses colonic anastomotic healing in the presence of a left-sided obstruction. (Received for publication on Mar. 29, 1999; accepted on Nov. 11, 1999)     

Effect of calcitonin gene-related peptide on anastomotic healing in the presence of endotoxin

BACKGROUND: Intestinal anastomotic healing is a complex procedure in which several mediators, cytokines and other substances play roles, as well as calcitonin gene-related peptide (CGRP). CGRP is capable of stimulating DNA synthesis and cell proliferation in endothelial cells by increasing vasodilatation and inflammatory response and promoting epithelial, vascular and mesothelial cell proliferation. This study was undertaken to investigate whether CGRP has a beneficial effect on intestinal anastomotic healing, even in septic conditions. METHODS: Four groups of 10 rats were administered normal saline (0.5 mL), lipopolysaccharide (LPS) (0.5 mg/kg), CGRP (0.5 mL 6.5 x 10(-10) mol/L) and LPS + CGRP (0.5 mg/kg + 0.5 mL 6.5 x 10(-10) mol/L) via intraperitoneal route, respectively, 24 h prior to operation and postoperatively. All rats underwent ileo-ileal end-to-end anastomosis. Anastomotic bursting pressure and tissue hydroxyproline levels were measured on postoperative day 7. RESULTS: Calcitonin gene-related peptide was found to have positive effects on both parameters of healing. The LPS-injected group showed intestinal anastomotic healing disorder suggesting impaired collagen production, which showed improvement after CGRP administration. CONCLUSIONS: Calcitonin gene-related peptide increases anastomotic wound healing in experimental intestinal anastomosis in the presence of endotoxin.     

Effects of pneumoperitoneum with or without colostomy on rat colonic anastomotic healing

Background: Elevated intra‐abdominal pressure and colostomy have adverse effects on colonic anastomoses. The aim of the present study was to investigate the effects of laparoscopic colon surgery with and without diverting colostomy on healing of colonic anastomoses in an experimental model. Methods: Thirty‐six male rats were divided into three equal groups: group 1, control (colonic anastomosis and anaesthesia for 180 min only); group 2, 180 min pneumoperitoneum and colonic anastomosis; and group 3, similar to group 2 with a proximal colostomy. On day 7, bursting pressures, tissue hydroxyproline and nitric oxide concentrations and histopathological inflammation scores were determined and compared. Results: Mean bursting pressures were higher in the control group than the two pneumoperitoneum groups (P = 0.0003). Mean tissue hydroxyproline concentrations showed no difference (P > 0.05). Mean tissue nitric oxide concentrations were significantly increased in the control group (P = 0.0013). Histopathological scores demonstrated increased inflammatory response in group 3 compared to the controls (P = 0.0009). Conclusion: Pneumoperitoneum delays collagen maturation and impairs anastomotic strength in the colon. Following pneumoperitoneum, performance of a diverting loop colostomy to protect the anastomosis will not have additional detrimental effects on anastomotic healing.     

Upregulation of VEGFR1 in a rat model of esophagogastric anastomotic healing

Introduction: Anastomotic leakage after gastrointestinal surgery is a significant cause of morbidity and mortality. Esophagogastric and colorectal anastomoses are vulnerable to leakage. Extended knowledge of growth factors and their receptors is needed to understand anatomic healing.

Methods: The expression pattern of vascular growth factor receptor (VEGFR1-3), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFRα/β) and keratinocyte growth factor receptor (KGFR) were analyzed by semiquantitative-PCR in the rat intestinal tract and in esophagogastric anastomosis 5d after surgery.

Results: VEGFR1, VEGFR2, EGFR, KGFR and PDGFRα expression was observed throughout the intestinal tract including esophagus, stomach, small bowl and colon. VEGFR3 was not found in gastric samples and PDGFRβ expression was not detected in the small bowl.

Semiquantitative analyses of the VEGFR1, PDGFRα and EGFR expression in esophagogastric anastomotic tissues revealed a 2-fold upregulation of the VEGFR1 in gastric samples, while no change was observed in the esophageal anastomotic side.

Conclusion: Our results revealed a distinct expression pattern of the investigated growth factor receptors in rat intestinal tract. Showing higher expression levels of growth factor receptors at the gastric anastomotic tissue at the fifth postoperative day suggests a different contribution of the gastric and the esophageal side to the anastomotic healing.     

The role of the spleen on colonic anastomotic healing.

The role of the spleen on wound healing remains unclear. This study investigates the effect of splenectomy on the healing of colonic anastomoses. Twenty-six Wistar rats were assigned into four groups: sham, splenectomy, anastomoses, and splenectomy and anastomoses. The rats underwent a standardized left colonic resection and primary anastomoses, and/or splenectomy. Bursting pressure and hydroxyproline content were used to evaluate anastomotic healing, five days postoperatively. No differences were found in the bursting pressure and hydroxyproline content between the groups. The present results indicate that splenectomy has no negative effect on the healing of colonic anastomoses in rats.     

Vasopressor use after initial damage control laparotomy increases risk for anastomotic disruption in the management of destructive colon injuries

Background

Management of destructive colon injuries during damage control (DC) laparotomy is debated. The authors reviewed a single institution's experience with destructive colon injuries to identify risk factors for anastomotic failure after colon reconstruction.

Methods

The authors identified all trauma patients sustaining destructive colon injuries between 2002 and 2011 from their medical center's trauma registry. Anastomotic leak was defined as suture or staple line disruption or enteral fistula formation.

Results

Of 171 identified patients, 68 had DC procedures, 41 (60%) had subsequent anastomoses performed during the same hospitalization, and 27 (40%) were diverted. The colon anastomotic leak rate in patients who underwent DC laparotomy was higher than in patients who were reconstructed at the primary operation in a non-DC setting (17% vs 6%, P = .09). The use of vasopressors after the initial DC operation more than quadrupled the leak rate to 50% (P = .02).

Conclusions

Colonic anastomotic disruptions yield deadly consequences, and diversion rather than anastomosis should be used in patients who require vasopressor support after the initial DC procedure.     

非甾体抗炎药物对结直肠吻合口愈合影响的研究进展

背景 非甾体抗炎药物(non-steroidal anti-inflammatory drugs,NSAIDs)是一类具有抗炎、镇痛和解热等作用的药物,其主要通过抑制环氧化物酶阻断花生四烯酸合成前列腺素而发挥解热、镇痛、抗炎作用.近年来,NSAIDs与麻醉药品并用于围手术期镇痛取得了良好的临床效果,尤其被广泛应用于手术后镇痛. 目的 吻合口漏是结直肠外科最严重的并发症之一,NSAIDs是否影响结直肠吻合口的愈合、增加吻合口漏的发生率文献报道不一. 内容 总结近年来关于NSAIDs对人体及实验动物结直肠吻合口愈合影响的代表性文献. 趋向 为手术后合理、安全使用NSAIDs提供参考,并总结NSAIDs对结直肠吻合口愈合影响的可能的机制.     

Modulation of growth factor and cytokine expression by nitric oxide during rat colon anastomotic healing

We have previously shown that inhibition of nitric oxide generated by inducible nitric oxide synthase (iNOS) results in impaired colon anastomotic healing. Therefore, we proceeded to assess whether disruption of iNOS activity alters the normal pattern of growth factor expression during anastomotic healing. Two groups of male Sprague-Dawley rats underwent distal colonic division and anastomosis, jugular venous catheterization and subcutaneous placement of polyvinyl alcohol sponges. The first group (n = 10) received q8 hour intravenous injections of 10 mg/kg L-N-iminoethyl-lysine (L-NIL, a selective inhibitor of iNOS), while the second group (n = 12) received equal volumes of saline. On postoperative day 5, animals were sacrificed and anastomotic bursting pressure was determined. Histologic sections of the anastomosis were subjected to in situ hybridization versus mRNA of the proteins listed below. Positive controls were reacted with a poly-thymidine (poly-T) probe versus ubiquitous mRNA poly-adenine tails. Positively stained cells were quantified using a calibrated optical grid encompassing 0.5 mm² area centered over the anastomosis. Results are reported as the number of positive cells per 1000 cells positive for poly-T. L-NIL treated animals demonstrated an 18% decrease in wound fluid NOX compared to controls (29.2 ± 1.2 vs. 34.6 ± 2.0 iM, mean ± SEM; P = 0.035). This corresponded to a 17% decrease in anastomotic bursting pressure (153 ± 4 vs. 182 ± 8 mm Hg, mean ± SEM; P < 0.05). L-NIL also markedly increased the number of cells expressing transforming growth factor-β, tumor necrosis factor-ct, vascular endothelial growth factor, and both inducible and endothelial forms of nitric oxide synthase. L-NIL had no effect on the expression of basic fibroblast growth factor. The data demonstrate that iNOS inhibition markedly disrupts the profile of cytokine and growth factor mRNA normally expressed during anastomotic healing. This provides in vivo evidence that NO modulates gene expression during anastomotic healing. Presented at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, California, May 21–24, 2000 (poster presentation). This work was supported by funding from grants NIH #GM54566(AB) and NIH #T32 DK07713-03.     

Effects of trapidil on the healing of colonic anastomoses in an experimental rat model

Background: Trapidil has various properties including vasodilatation, inhibition of lipid peroxidation and platelet aggregation as well as, and reduction of, the inflammatory response to injury. The aim of the present study was to investigate the effects of trapidil on dexamethasone‐impaired colonic anastomotic healing in an experimental rat model. Methods: Twenty‐four Wistar rats underwent colonic transsection and primary anastomosis. Rats were divided into four groups of six: group 1 (G1), control; group 2 (G2) trapidil, 8 mg/kg per day intravenously; group 3 (G3) dexamethasone, 0.1 mg/kg per day intramuscularly; and group 4 (G4) dexamethasone 0.1 mg/kg intramuscularly and trapidil 8 mg/kg intravenously per day, for 1 week. Anastomotic bursting pressure, hydroxyproline level, histopathological grading, malondialdehyde and nitrite/nitrate levels were determined. Results: Dexamethasone‐impaired anastomotic healing was found to be improved by trapidil administration in terms of anastomotic bursting pressure and hydroxyproline content (P = 0.026, and P = 0.017). In addition, histopathological examination revealed an increase in fibroblast proliferation and collagen deposition (P = 0.004, and P = 0.015) and a decrease in leucocyte infiltration (P = 0.004). Moreover, serum nitrite/nitrate and malondialdehyde levels decreased when G3 was compared to G4 (P < 0.001, P= 0.38). Conclusions: Trapidil may improve the dexamethasone‐impaired anastomotic healing due to its preventive effects on inflammatory response and lipid peroxidation in rats.     

Effect of fibrin sealant on the healing colonic anastomosis in the rat

Fibrin adhesives have been advocated as a protective seal in colonic anastomosis to prevent leakage. In order to assess the effect of fibrin glue sealing we compared the healing of sutured colonic anastomosis in the rat (group 1) with the addition of human-derived fibrin sealant (group 2). As a control for a possible reaction to foreign protein, in group 3 the sutured anastomosis was sealed with specially prepared rat fibrin adhesive. On days 2, 4 and 7, ten animals in each group were killed. Adhesion formation was scored and the in situ bursting pressure was measured. The collagen concentration and degradation were estimated by measuring hydroxyproline. Adhesion formation was significantly increased in groups 2 and 3 compared with the control group. On days 2 and 7 the bursting pressure was not different between the groups. On day 4 the bursting pressure in groups 2 and 3 was significantly lower than in group 1 (P less than 0.001). These findings correspond with the results of collagen measurements. On day 4 the concentration of hydroxyproline was significantly reduced in groups 2 and 3. Histological examination showed infiltration of neutrophilic granulocytes into the sealant on days 2 and 4; on day 7 the sealant had vanished. From these results it is concluded that fibrin sealing of the colonic anastomosis in the rat does not improve healing, as demonstrated by bursting pressure and hydroxyproline concentration. On the contrary, it seems to have a negative influence.     

Effects of Cholerella sp. microalgae extract on colonic anastomosis in rats with protein–energy malnutrition

Objective  Algae, which are used as supplementary nutrients in various countries, are products rich in protein, vitamins and minerals. The aim of this study was to investigate the effects of algae extracts on the healing of colonic anastomosis in malnourished rats. Method  Seventy‐two rats were randomized to three groups. Group 1 was fed with standard diet for 15 days, before and after the colonic anastomosis. Groups 2 and 3 were fed with a malnutrition diet for 15 days prior to colonic anastomosis and then with the basic diet for 15 days there after. Group 3 also received an extract of algae derived from Cholerella sp. via oral gavage postoperatively, in addition to the basic diet. Rats were killed on the 3rd, 7th and 15th postoperative day. Blood samples were collected to evaluate prealbumin, transferring and albumin levels. Anastomotic bursting pressures (BPs), histopathology and tissue hydroxyproline levels were evaluated after killing. Results  In group 3, the prealbumin level on the 3rd postoperative day and transferrin and albumin levels on the 7th and 15th postoperative days were significantly increased compared with the other groups (P < 0.05). Tissue hydroxyproline levels and anastomotic BPs of group 3 were significantly higher than in group 2 on the 3rd, 7th and 15th postoperative days (P < 0.05). Histopathological examination of the anastomosis revealed significantly better healing patterns for group 3 than for groups 1 and 2 (P < 0.05). Conclusion  Extract derived from Cholerella sp. microalgae has favourable effects on healing of experimental colon anastomoses.     

Effects of intraperitoneal chemotherapy on anastomotic healing in the rat

The effect of perioperative intraperitoneal (ip) (2 mg/kg) vs intravenous (iv) (1.5 mg/kg) mitomycin-C on healing of intestinal anastomoses was studied in rats after jejunal section and anastomosis. When the animals were killed 7 days after surgery 52.8% in the ip group had an anastomotic leak (41.2% causing death of the animals), compared to 20% in the iv group and none in the control group. Mean anastomotic bursting pressure was 156 mm Hg in the ip group, 178 mm Hg in the iv group, and 203 mm Hg in controls (P less than 0.01). Hydroxyproline content of the intestinal segment containing the anastomosis was 2.26 micrograms/mg in the ip group, 3.49 in the iv, and 4.91 in controls (ip vs controls, P less than 0.01). Histological examination of the anastomoses in rats given ip mitomycin showed significantly "slower" anastomotic healing than in iv rats and controls. Electron microscopy showed that the mean diameter of collagen fibers was significantly smaller (P less than 0.05) in ip rats (34 nm) than iv (51 nm) and controls (79 nm). An intraoperative bolus of mitomycin thus significantly impaired the healing of a jejunal anastomosis in the rat, more so after ip than iv injection. Thus in clinical practice ip adjuvant chemotherapy after surgery should perhaps be delayed until wound repair has reached an advanced stage.     

Airway anastomotic healing in the rat tracheal autograft

The healing of airway anastomoses after tracheal autotransplantation was studied in a rat model. Tracheal autotransplantation in length of five tracheal cartilaginous rings was performed in 46 PVGr1 female rats. The animals were sacrificed and divided into six groups as follows: 0-day control group, and 3-, 7-, 14-, 21- and 28-day study groups (n = 6-7/group). In laser Doppler measurements, blood flow was significantly increased in the lower anastomosis after day 7 and in the upper anastomosis after day 21 compared with the control group (p < 0.05). The breaking strength of the tracheal autograft increased after day 7 compared with the control group (p < 0.05). The total collagen content of the lower anastomosis was significantly decreased on days 3 and 7 compared with the control group (p < 0.05), but thereafter it increased constantly. In the upper anastomosis on days 3 and 7, there were significant histological alterations, especially in the tracheal epithelium, compared with the control group (p < 0.05). Tracheal anastomosis is most vulnerable during the first 7 days.