Colonic Wound Healing Research Articles

Small intestinal submucosa for reinforcement of colonic anastomosis

Different materials have been evaluated for anastomotic reinforcement to prevent gastrointestinal anastomotic leakage. In this experimental study, small intestinal submucosa (SIS) was tested as a sealing for stapled colonic anastomosis in a porcine model. The aims of this study were to determine the macroscopic and microscopic outcomes and to evaluate the safety and feasibility of applying SIS for anastomotic sealing. Circular stapled anastomoses were performed in 18 pigs. Standard anastomosis in the control group (n = 8) was compared to an SIS-sealed anastomosis in the study group (n = 10). After 30 days, anastomotic segments were examined for macroscopic and microscopic regeneration and their resistance to mechanical stress. Furthermore, animal survival and clinical course were evaluated. None of the animals developed anastomotic leakage, intraabdominal abscess, or peritonitis. Shrinkage of SIS was evident in nine of ten animals. Encapsulation and displacement of the SIS patches were seen in two animals. Quantity of anastomotic granulation tissue and rate of complete mucosal coverage of anastomotic line were increased in SIS-sealed anastomoses without reaching significance. Moreover, no significant differences were found in the rate of survival of the animals, anastomotic stricture formation, intraabdominal adhesions, anastomotic bursting pressure, and microscopic healing parameters of the anastomosis between stapled colonic standard anastomosis and anastomosis protected by SIS. The results of this study indicate a safe use of SIS for anastomotic reinforcement in a porcine model. Adverse effects like strictures, increased adhesions, and anastomotic abscesses were absent. Promoting effects on colonic wound healing by SIS were microscopically evident. The results argue for a careful clinical evaluation in humans.

The Effects of Resveratrol on the Healing of Left Colonic Anastomosis

Introduction: Resveratrol (RSV) is a natural polyphenolic compound found in grape skins and the red wine which improves histological reorganization of the regenerating tissue in dermal wound healing. Since anastomotic healing possesses paramount importance to prevent complications in colorectal surgery, the present study is aimed to evaluate the effect of RSV on the healing of experimental left colonic anastomoses. Methods: Thirty-two male Wistar albino rats were randomized into two groups and subjected to colonic anastomosis. The study group was treated with RSV and the control group received tap water instead. The rats were sacrificed 3 and 7 days postoperatively. Wound complications, intra-abdominal abscesses, and anastomotic leaks and stenosis were recorded. Four types of assessment were performed: bursting pressure, hydroxyproline (OHP) content, histopathology, and biochemical analysis. Results: Compared to the control group, the RSV-treated rats displayed a higher bursting pressure (p <. 001) and anastomotic OHP content (p <. 05)]. RSV treatment leads to significant increase in PON activity at both time points and decrease in malondialdehyde levels on postoperative day 3 (p <. 001). Histopathological analysis revealed that RSV administration leads to a better anastomotic healing in terms of mucosal ischemia, neovascularization, reepithelialization, fibroblast, and lymphocyte infiltration. Conclusion: The study results suggest that exogenous RSV administration exerts a positive effect on experimental colonic wound healing in the rat. Although the precise cellular mechanisms by which RSV enhances anastomotic wound healing is not clear, stimulation of neovascularization, generation of collagen synthesis, inhibition of overinflammation, and restriction of oxidative injury seems to be of paramount importance.

Effects of a static magnetic field on wound healing: results in experimental rat colon anastomoses

Background Research has shown that pulsed electromagnetic fields (EMFs) promote wound healing in experimental colonic anastomosis; however, the effects of static EMFs in this setting have not been investigated to date. Methods Fifty male Wistar rats were used. Ten served as controls for mechanical strength testing, and the other 40 underwent descending colon resection and anastomosis. Twenty of these 40 animals (M group) had NeFeB magnets placed in contact with the anastomosis site (magnetic field strength at the site 390 to 420 G). The other 20 animals (sham [S] group) had nonmagnetized NeFeB bars of the same dimensions and weight implanted. Half of the animals in each group were killed and assessed for healing parameters on postoperative day 3 (M3 and S3 groups) and the other half on postoperative day 7 (M7 and S7 groups). Four types of assessment were done: gross healing, mechanical strength, hydroxyproline deposition, and histopathology. Results There were no differences between the M and S animals with respect to gross healing parameters. The mechanical strength was also not different between groups (23.8 ± 12.7 and 24.7 ± 9.6 mm Hg for M3 and S3, respectively; P = .863 and 91.3 ± 65.4 and 94.8 ± 55.9 mm Hg for M7 and S7, respectively; P = .902). Similarly, hydroxyproline deposition was not different between groups on postoperative day 3 or day 7. On postoperative day 3, the M group had significantly higher scores than the S group for fibroblast infiltration (2.4 ± 0.7 vs 1.4 ± 0.7, respectively; P = .008) and capillary formation (2.5 ± 0.7 vs 0.9 ± 0.4, respectively; P <.001). However, these effects were reversed and did not endure by day 7. Conclusions The study results suggest that static EMF has no effect on experimental colonic wound healing in the rat.

The healing of colon anastomosis covered with fibrin glue after early postoperative intraperitoneal chemotherapy

After colon resection for colonic cancer, the administration of antineoplastic agents may prolong survival by killing residual cancer calls and preventing metastasis, but may also slow anastomotic healing. This study was designed to determine the effects of 5-fluorouracil (5-FU) and leucovorin (LEV), injected intraperitoneally, on the healing of colonic anastomoses with or without fibrin glue (FG) covering. Sixty rats were randomized to one of four groups. After resection of a transverse colon segment, an end-to-end sutured anastomosis was performed. Rats in the 5-FU+LEV and the 5- FU+LEV+FG groups received 5-FU+LEV intraperitoneally. The colonic anastomoses of the rats in the FG group and in the 5-FU+LEV+FG group were covered with fibrin glue. All rats were killed on postoperative day 8. Bursting pressure measurements were recorded and the anastomoses were examined macroscopically and histologically. The leakage rate of the anastomoses was significantly different among groups. Specifically, the leakage rate was significantly higher in the 5-FU+LEV group (40%) than in the FG and in the 5-FU+LEV+FG groups where there were no leakages (p=0.017). The mean adhesion formation score was significantly higher in rats of the 5-FU+LEV group, compared to the control (p=0.023), the FG (p=0.006) and the 5-FU+LEV+FG (p=0.006) groups. Bursting pressures were significantly lower in the 5-FU+LEV group than in the other groups (p<0.001). Also, bursting pressures were significantly lower in the control group compared to the FG and 5-FU+LEV+FG groups (p<0.001). Rats in the 5-FU+LEV+FG group had significantly greater neoangiogenesis and fibroblast activity than those in the 5-FU+LEV group (p=0.025). The early intraperitoneal postoperative administration of 5-fluorouracil plus leucovorin impaired colonic wound healing. However, the application of fibrin glue prevented the deleterious effect of chemotherapy.

Effect of blood transfusion on gene expression of transforming growth factor beta-1 and the alpha subunit of interleukin 2 receptor in a model of colonic wound healing

Blood transfusions have been shown in the past to compromise wound healing in experimental models of colonic anastomosis. Transforming growth factor beta (TGFbeta) has been proposed to play a major role in the process of colonic wound healing, and its expression is believed to be modulated by interleukin-2 (IL2). According to an earlier report, the postoperative administration of the histamine receptor-2 antagonist ranitidine increases the blood levels of soluble IL2 receptor in humans undergoing abdominal surgery and could thus affect molecular determinants of colonic anastomosis. In this study we examined the effect of blood transfusions, with and without ranitidine administration, on the gene expression of TGFbeta(1) and the specificity-conveying alpha subunit of the receptor for IL2, in rat perianastomotic tissue. Analysis of gene expression by semiquantitative RT-PCR revealed a tendency for downregulation of both genes, albeit in a statistically nonsignificant manner. This effect was not prevented by the postoperative administration of ranitidine. On the other hand, there appears to be a significant correlation between expression of TGFbeta(1) and that of IL2 receptor alpha subunit, irrespective of treatment.

Effect of aging on the healing of colonic anastomoses in rats

PURPOSE: To evaluate the healing of the colonic anastomoses in old and young adult rats. METHODS: Fifty six Wistar rats were allocated in two groups, the young animals aged on average 110 days and the old animals aged average 762 days. Under anesthesia, the rats underwent a midline laparotomy and the colon was sectioned 2 cm above the peritoneal deflection. An end-to-end interrupted one layer colonic anastomosis was performed and the animals sacrificed on the 3rd, 7th, 14th and 21st postoperative days. A 4 cm segment of colon containing the anastomosis was submitted to bursting pressure tests. The paraffin-embedded tissue blocs were sectioned and stained with haematoxylin and eosin and Sirius Red. Histochemical methods such as PCNA, LCA and CD34 were also used. RESULTS: The colonic anastomosis resistance was greater in the old rats group on the 3rd postoperative day (p=0,0000). Collagen concentration was higher in the anastomosis of the young animals on the 14th and 21st postoperative days (p=0,0475, p=0,0346 respectively), with a significantly greater concentration of collagen type I. The concentration of collagen type III, the epithelial lining rate and the angiogenesis were similar in the study groups. CONCLUSION: Despite some differences between the two groups regarding the healing process and considering that failures in the colonic anastomosis wound healing could not be demonstrated, we can concluded that aging itself does not interfere in the wound healing process.

Sustained local application of low-dose epidermal growth factor on steroid-inhibited colonic wound healing

Background/purpose The effects of locally administered low-dose epidermal growth factor in a steroid-inhibited wound healing were investigated in a rat model. Methods Long-acting release of epidermal growth factor was enabled using microspheres embedded in gelatin sponge. Study groups consisted of 60 rats with 10 in each: colonic anastomosis only (C), plus pure gelatin sponge (CG), plus epidermal growth factor loaded sponge (CE), colonic anastomosis and steroid (S), plus gelatine sponge (SG), and plus epidermal growth factor-loaded gelatine sponge (SE) groups. Bursting pressure and wound hydroxy-proline content were measured. Bursting sites were recorded. Collagen deposits, inflammation, and foreign body reactions were evaluated. Results Bursting pressure and hydroxy-proline contents were found lowest in the S and highest in the CE groups ( P < .01). There was almost no difference between C and SE groups. Bursts were encountered in peri-anastomotic normal colon sites in the nonsteroid-treated C, CG, and CE groups. They were noted overwhelmingly at the anastomosis in steroid-inhibited S, SG, and SE groups. Histopathology results showed a standstill at the inflammatory phase of healing in S and SG groups. The best healing was observed in the CE group. Degree of collagen accumulation was well correlated with bursting pressure and hydroxy-proline content data with a negligible foreign body reaction to gelatine sponge. Conclusions Continuous local epidermal growth factor administration by microspheres in gelatin increases wound collagen and further enhances healing in colonic anastomoses even with steroid inhibition.

Estudos biomecânicos da ação de aderências sobre anastomose cólica: trabalho experimental em ratos

OBJETIVO: Avaliar a ação de aderências sobre anastomose em cólon descendente de ratos por meio de análises biomecânicas. MÉTODOS: Noventa ratos foram distribuídos igualmente em três grupos. O Grupo 1 submeteu-se ao teste Pressão de Ruptura à Distensão por Líquido, enquanto que os Grupos 2 e 3, aos testes Força de Ruptura à Tração e Tensão Resultante Final de Ruptura à Tração, respectivamente. Cada grupo foi subdividido em 3 subgrupos contendo 10 animais. Um subgrupo foi analisado com as aderências deixadas intactas ao redor da anastomose; em outro, as aderências foram removidas, enquanto no último não se permitiu a fixação de aderências nas anastomoses por meio de proteção com película de polivinilcloreto (P.V.C.). RESULTADOS: A eutanásia ocorreu no quinto dia pós-operatório e os subgrupos com as aderências intactas nas anastomoses apresentaram maior resistência à ruptura em relação aos subgrupos com aderências removidas. Os subgrupos com ausência de aderências nas anastomoses apresentaram menor resistência à ruptura (Grupo1-p=0,0001, Grupo 2-p=0,0003 e Grupo3-p=0,0001). CONCLUSÃO: Aderências constituem influências benéficas sobre a anastomose, aumentando a sua resistência mecânica na fase inicial do reparo tecidual.

Reciprocal regulation of gastrointestinal homeostasis by SHP2 and STAT-mediated trefoil gene activation in gp130 mutant mice.

The intracellular signaling mechanisms that specify tissue-specific responses to the interleukin-6 (IL-6) family of cytokines are not well understood. Here, we evaluated the functions of the two major signaling pathways, the signal transducers and activators of transcription 1 and 3 (STAT1/3) and the Src-homology tyrosine phosphatase 2 (SHP2)-Ras-ERK, emanating from the common signal transducer, gp130, in the gastrointestinal tract. Gp130(757F) mice, with a 'knock-in' mutation abrogating SHP2-Ras-ERK signaling, developed gastric adenomas by three months of age. In contrast, mice harboring the reciprocal mutation ablating STAT1/3 signaling (gp130(Delta STAT)), or deficient in IL-6-mediated gp130 signaling (IL-6(-/-) mice), showed impaired colonic mucosal wound healing. These gastrointestinal phenotypes are highly similar to the phenotypes exhibited by mice deficient in trefoil factor 1 (pS2/TFF1) and intestinal trefoil factor (ITF)/TFF3, respectively, and corresponded closely with the capacity of the two pathways to stimulate transcription of the genes encoding pS2/TFF1 and ITF/TFF3. We propose a model whereby mucosal wound healing depends solely on activation of STAT1/3, whereas gastric hyperplasia ensues when the coordinated activation of the STAT1/3 and SHP2-Ras-ERK pathways is disrupted.

Regulation of matrix metalloproteinases in a model of colonic wound healing in a rabbit.

Matrix metalloproteinases occur in the colon at an anastomosis but not in the normal colon. Matrix metalloproteinase synthesis can be regulated by cytokines, for example interleukin-1 beta and growth factors, such as transforming growth factor beta and basic fibroblast growth factor. The aim of this study was to investigate the regulation of matrix metalloproteinases at an anastomosis by identifying the cell types that synthesize matrix metalloproteinases, examining factors that might regulate their synthesis, determining whether they occur in an active form, and assessing the effect of suture type on these parameters. An anastomosis was formed in the distal colon of rabbits using either polyglactin or polydioxanone and the animals were killed six hours or seven days later. The distribution of matrix metalloproteinases and cytokines and the cell types were assessed by immunohistochemistry. Matrix metalloproteinase-2, matrix metalloproteinase-3, and matrix metalloproteinase-9 were detected also by zymography. Immunohistochemistry showed that matrix metalloproteinases were restricted to the suture line. Although zymography demonstrated that matrix metalloproteinase-2 was present mainly in an active form, matrix metalloproteinase-9 and matrix metalloproteinase-3 were present in the pro-form. The active form of matrix metalloproteinase-3 occurred more often in the polydioxanone-sutured rabbits. With the exception of matrix metalloproteinase-9, the matrix metalloproteinases were synthesized by fibroblasts. Interleukin-1 beta and transforming growth factor beta were more widespread than in the normal colon and were localized adjacent to the matrix metalloproteinases. Basic fibroblast growth factor was also more widespread postoperatively but occurred deeper in the anastomosis than the matrix metalloproteinases. This study has shown that interleukin-1 beta and transforming growth factor beta may regulate the synthesis of the matrix metalloproteinases by fibroblasts and that minor differences that occur in the matrix metalloproteinase profile are dependent on the suture type.

A ação dos ácidos graxos de cadeia curta na cicatrização de anastomoses colônicas: estudo experimental em ratos

Os ácidos graxos de cadeia curta (AGCC) derivam da fermentação das fibras ingeridas na dieta e atuam como substrato das células da mucosa colônica. O presente estudo tem como objetivo avaliar a ação dos AGCC na cicatrização do cólon. Utilizaram-se 16 ratos fêmea divididos em 2 grupos de 8 animais. No grupo controle (HC) os animais foram submetidos à cirurgia de Hartmann e infusão pós-operatória de solução salina isotônica via retal por 7 dias. No grupo experimento (HA) a solução salina foi substituída por solução isosmolar contendo AGCC. Nos animais do grupo controle, a pressão média de ruptura do segmento distal do cólon foi de 128,37 mmHg, sendo este valor de 137,25 mmHg no grupo experimento (p=0,5693). A avaliação histológica em hematoxilina-eosina foi semelhante nos dois grupos estudados. A densitometria do colágeno demonstrou concentração significativamente maior de colágeno maduro (tipo I) no grupo experimento, quando comparado com o grupo controle (p=0,0094). O colágeno total também foi mais encontrado no grupo experimento, comparado-se com o grupo controle (p=0,0371). Conclui-se que os ratos submetidos à infusão intraluminal de AGCC têm maior concentração de colágeno maduro e total na linha de sutura do coto retal, quando comparados com o grupo controle.

Cicatrização de anastomoses do cólon esquerdo com doença inflamatória: estudo experimental em ratos

Complicações relacionadas com a anastomose são descritas com freqüência nas cirurgias para o tratamento da doença inflamatória do cólon. Para conhecer a interferência da inflamação na cicatrização de anastomoses 40 ratos Wistar são utilizados e divididos em 2 grupos. Um deles serviu de controle e no outro induziu-se doença inflamatória com ácido acético 10% por sondagem retal. No sétimo dia procedeu-se à laparotomia em ambos os grupos, colotomia e anastomose término-terminal com pontos separados em plano único. Avaliadas no terceiro e sétimo dias, pode-se verificar que o número de complicações no grupo de animais com doença inflamatória foi maior assim como a mortalidade. As deiscências com peritonite foi a situação mais comum (p=0,0222). A capacidade de suportar pressão, nas anastomoses que evoluíram sem complicações foi menor nestes cólons, porém a diferença quando comparada ao controle não foi significante (p=0,0836). Verificou-se que as anastomoses construídas em cólons com doença inflamatória apresentavam maior concentração de colágeno total, com predomínio de colágeno imaturo (tipo III) (p=0,0000) enquanto que nas feitas em cólons normais predominava colágeno maduro (tipo I) (p=0,0102). Observou-se ainda que a organização do colágeno era menor, no terceiro dia, nas anastomoses com doença inflamatória. Entretando a análise da reação inflamatória ao nível da anastomose foi semelhante nos dois grupos. Estes resultados permitem sugerir que a doença inflamatória leva a aumento do número de deiscências provavelmente pelo atraso da maturação e ordenação do colágeno.

Comparison of two closure techniques for the repair of experimental colonic perforations.

Primary repair of penetrating wounds of the colon is gaining increasing acceptance in surgical practice. This study compared two techniques for the repair of experimental colonic perforations in the presence of peritonitis. Multiple colonic perforations were created in the colon of 24 pigs. Following a 6-h delay the perforations were closed either by local excision and suture or by skin staples applied to the seromuscular layers of the colon. The repairs were assessed biomechanically and histologically for up to 14 days after surgery. All animals had diffuse peritonitis at the time of colonic repair. Stapled repairs were completed significantly faster than sutured repairs (mean(s.d.) 4.8(1.6) versus 30.7(4.0) min, P < 0.001). Bio- mechanical evaluation of repairs revealed no significant differences between the two techniques. Histological examination of repairs closed by staples demonstrated more advanced healing compared with suture closure, on the basis of tissue apposition and inflammatory changes. Experimental colonic injuries may be treated successfully by primary repair in the presence of peritonitis. The use of skin staples for repair does not appear to prejudice colonic wound healing.

Should Colon-Penetrating Small Missiles Be Removed? An Experimental Study of Retrocolic Wound Tracks

Small-fragment injury to the colon may occur in approximately 5% of battlefield casualties. The surgical management aims to reduce the risk of retrocolic infection and provide optimal conditions for colonic wound healing. This study aimed to quantify the risk of retrocolic infection. Steel fragments were fired through exteriorized porcine colon and caught in 20% gelatin. The fragments, and resultant tracks, were extracted and subjected to quantitative bacteriological examination to determine the extent of contamination. The median bacterial count for complete tracks was 1.2 104 CFU/g (interquartile range 1.8 103 to 2.7 104). Counts were highest in the initial 1 cm of the track and reduced along its length. This study does not support wound track excision or missile fragment removal in cases of retrocolic trauma following penetrating colonic injury. Either or both procedures will increase local trauma and are likely to prejudice colonic wound repair.

Temporal Expression of TGF-β1, EGF, and PDGF-BB in a Model of Colonic Wound Healing

Background.Dehiscence of colonic anastomoses is a multifactorial phenomenon. One mechanism by which this can occur is a deficiency of colonic submucosal collagen. Peptide growth factors (PGFs) have been shown to play a role in the synthesis, deposition, and maturation of collagen. Specifically, in tissues other than the colon, the transforming growth factor-beta (TGF-β1) gene has been shown to be temporally associated with expression of the procollagen gene. This study examines the temporal expression of the TGF-β1, epidermal growth factor (EGF), and platelet-derived growth factor B (PDGF-BB) genes and their temporal relationship to the expression of the procollagen type 1 (PROC I) gene.Materials and methods.Forty-eight Sprague-Dawley rats underwent transection of the descending colon with primary anastomosis. Perianastomotic colonic tissue was harvested on Day 0 and postoperative days 3, 5, 6, 7, and 14. Colonic tissue was analyzed using semiquantitative reverse transcriptase-polymerase chain reaction and primers specific for the TGF-β1, EGF, and PDGF-B growth factors. Relative expression ratios of PGFs and PROC I genes were calculated versus a constitutive gene.Results.The data show that although all three of the PGFs genes were expressed in healing postoperative colonic tissue, only TGF-β1showed a significant increase in its level of expression versus a constitutive gene from a mean ratio of 0.4 ± 0.08 on Day 0 to a mean ratio of 1.9 ± 0.27 on Day 7 (P< 0.0001 by ANOVA). The PROC I gene also showed a significant increase in expression (P< 0.001 by ANOVA) in the postoperative period which temporally correlated with the increase in the expression of the TGF-β1gene (r= 0.89,P< 0.05).Conclusions.The temporal correlation between an increase in the gene expression of TGF-β1and PROC I is initial evidence that that TGF-β1plays a significant role in collagen metabolism in a healing colonic anastomosis.

The effect of tacrolimus on colon anastomotic healing

We have shown that the immunosuppressant tacrolimus (TA), used in solid organ transplantation, decreases wound mechanical strength and collagen deposition in dermal wound healing~ Failure of colonic healing has a major impact on surgical morbidity and mortality. Whether tacrolimus affects the outcome of colonic healing, however, is not known. We, therefore, studied the effect of systemic treatment with tacrolimus on standard parameters of colonic wound healing in rats. Groups of eight Sprague Dawley rats underwent laparotomy and single layer 6-0 prolene inverted left colon anastomosis. Beginning at the day of wounding, rats were treated once daily by s.c. injections with 2.0, or 5.0 mg TA/kg. Rats were sacrificed at postoperative day five for determination of colonic bursting pressure (BP) and hydroxyproline content of anastomoses (OHP), an index of reparative collagen deposition. Splenic lymphocytes were tested for proliferative activity (3H-thymidine uptake ). Tacrolimus levels in blood, obtained by cardiac puncture at the day of sacrific e, were measured by ELISA.

Variations of magnesium, iron, copper and zinc during the colonic wound healing process: experimental study on rabbits.

The role of trace elements in the wound-healing process is still controversial. Their variations within a normal colonic wound healing have never been studied. An experimental study on rabbits was designed to study magnesium, iron, copper and zinc variations in blood, normal colonic walls and colonic anastomoses on each of the first 7 postoperative days. No major variations of Mg could be observed. Fe decreased in blood as well as in colonic walls and anastomoses. Cu increased in blood, whereas it decreased in colonic walls and anastomoses. Zn decreased in blood, whereas it increased in colonic walls without significant changes in anastomoses. The role of Fe seemed to be rather difficult to understand. Plasma mobilization seems to explain the local use of Zn, while early tissue release with further return in blood occurred for Cu. The importance of a well-balanced nutritional status is underlined to prevent and correct the variations of trace elements in the postoperative course.