The prevention of colorectal anastomotic leakage with tissue adhesives in a contaminated environment is associated with the presence of anti-inflammatory macrophages

In Situ Forming Injectable Gelatin-Based Antibacterial Bioadhesives for Preventing Postoperative Leakage and Abdominal Adhesions

Postoperative anastomotic leakage (AL) and abdominal adhesions are two major complications after intestinal surgery, with an incidence of 2-25% for AL and 93% for adhesion. Until now, there is no method addressing AL and abdominal adhesions simultaneously. In this work, Bi-PEG-succinimidyl succinate (PEG-NHS), amino-gelatin (Agel) is combined with cefoperazone-sulbactam (SCF) to prepare a multifunctional bioadhesive (SCF/SEAgel) for the postoperative leakage and adhesion prevention. SCF/SEAgel possesses a great sealing capability for tissue, with a bursting pressure of 54 kPa. The loaded SCF endows the systems with good antibacterial properties. The in vivo antiadhesion experiments show that SCF/SEAgel possesses better anti-adhesion properties than the commercially used sodium hyaluronate gel. In the cecum leakage model, the SCF/SEAgel effectively seals the leakage with a survival rate of 100%, superior to commercial products (Sainaoning). Meanwhile, it significantly reduces tissue adhesion. Finally, the laparoscopic surgery with dogs shows that the SCF/SEAgel can be injected through minimally invasive surgery, demonstrating its ease of use. Combined with its great biocompatibility, SCF/SEAgel is very promising in intestinal surgery.

Alpha-1-antitrypsin improves anastomotic healing in intestinal epithelial cells model

PURPOSE

Intestinal anastomosis is a routine procedure in pediatric surgery, with leakage being a significant complication. Human alpha1-antitrypsin (AAT), whose physiological serum concentrations range from 0.9-2.0 mg/ml, is known to accelerate wound healing and stimulate the expression of cell proliferation-related genes. We hypothesized that AAT might enhance anastomotic healing.

METHODS

In a monolayer of non-tumorigenic HIEC-6 epithelial cells derived from fetal intestine a scratch was created. Standard medium without (control) or with AAT (0.5 and 1 mg/ml) was added. Cells were observed using a Life-Cell Imaging System. Cell proliferation was assessed, and the expression of proliferation-related genes was measured by qRT-PCR.

RESULTS

In the presence of AAT, the scratch closed significantly faster. Cells treated with 1 mg/ml AAT showed 53% repopulation after 8 h and 97% after 18 h, while control cells showed 24% and 60% repopulation, respectively (p < 0.02). The treatment with AAT induced HIEC-6-cell proliferation and significantly increased the mRNA-expression of CDKN1A, CDKN2A, ANGPTL4, WNT3 and COL3A1 genes. AAT did not change the mRNA-expression of CXCL8 but decreased levels of IL-8 as compared to controls.

CONCLUSION

At physiological concentrations AAT accelerates the confluence of intestinal cells and increases cell proliferation. The local administration of AAT may bear therapeutic potential to improve anastomotic healing.

Suture reinforcement using a modified cyanoacrylate glue to prevent anastomotic leak in colorectal surgery: a prospective multicentre randomized trial : The Rectal Anastomotic seaL (ReAL) trial

BACKGROUND

Anastomotic leakage (AL) is the most frequent life-threating complication following colorectal surgery. Several attempts have been made to prevent AL. This prospective, randomized, multicentre trial aimed to evaluate the safety and efficacy of nebulised modified cyanoacrylate in preventing AL after rectal surgery.

METHODS

Patients submitted to colorectal surgery for carcinoma of the high-medium rectum across five high-volume centres between June 2021 and January 2023 entered the study and were randomized into group A (anastomotic reinforcement with cyanoacrylate) and group B (no reinforcement) and followed up for 30 days. Anastomotic reinforcement was performed via nebulisation of 1 mL of a modified cyanoacrylate glue. Preoperative features and intraoperative and postoperative results were recorded and compared. The study was registered at ClinicalTrials.gov (ID number NCT03941938).

RESULTS

Out of 152 patients, 133 (control group, n = 72; cyanoacrylate group, n = 61) completed the follow-up. ALs were detected in nine patients (12.5%) in the control group (four grade B and five grade C) and in four patients (6.6%), in the cyanoacrylate group (three grade B and one grade C); however, despite this trend, the differences were not statistically significant (p = 0.36). However, Clavien-Dindo complications grade > 2 were significantly higher in the control group (12.5% vs. 3.3%, p = 0.04). No adverse effects related to the glue application were reported.

CONCLUSION

The role of modified cyanoacrylate application in AL prevention remains unclear. However its use to seal colorectal anastomoses is safe and could help to reduce severe postoperative complications.

Clinical results after external reinforcement of colorectal anastomosis: a systematic review

OBJECTIVE

The aim of this review is to describe and assess the existing methods to cover colorectal anastomoses with biomaterials and their clinical impact in reducing anastomotic leakage (AL).

SUMMARY BACKGROUND DATA

The most serious complication in colorectal surgery is AL. Despite improvements in its diagnosis and management, AL remains an unresolved issue. To prevent its appearance and clinical consequences, different external reinforcement techniques with synthetic or biomaterials have been described.

METHODS

A systematic review search of the available literature until June 2022 was performed, looking for all literature regarding external reinforcement of colonic or colorectal anastomoses. After the review process, a classification of materials was proposed into solid and liquid materials, and an assessment of their clinical impact was performed. The study protocol has been registered at PROSPERO and has been reported in the line with PRISMA and AMSTAR Guidelines 11,12 .

RESULTS

Ninety-seven articles that fulfilled inclusion criteria, were identified and revised. Overall, 18 of the selected articles focused on human clinical trials and 79 on animal models. Only fibrin sealants, collagen patches, and omentoplasty have shown positive results in humans.

CONCLUSIONS

Fibrin sealants, collagen patches, and omentoplasty are, so far, the most studied biomaterials. However, further studies are required to confirm these findings before definite recommendations can be made.

Bio-Inspired Self-Healing, Shear-Thinning, and Adhesive Gallic Acid-Conjugated Chitosan/Carbon Black Composite Hydrogels as Suture Support Materials

The occurrence of leakage from anastomotic sites is a significant issue given its potential undesirable complications. The management of anastomotic leakage after gastrointestinal surgery is particularly crucial because it is directly associated with mortality and morbidity in patients. If adhesive materials could be used to support suturing in surgical procedures, many complications caused by leakage from the anastomosis sites could be prevented. In this study, we have developed self-healing, shear-thinning, tissue-adhesive, carbon-black-containing, gallic acid-conjugated chitosan (CB/Chi-gallol) hydrogels as sealing materials to be used with suturing. The addition of CB into Chi-gallol solution resulted in the formation of a crosslinked hydrogel with instantaneous solidification. In addition, these CB/Chi-gallol hydrogels showed enhancement of the elastic modulus (G') values with increased CB concentration. Furthermore, these hydrogels exhibited excellent self-healing, shear-thinning, and tissue-adhesive properties. Notably, the hydrogels successfully sealed the incision site with suturing, resulting in a significant increase in the bursting pressure. The proposed self-healing and adhesive hydrogels are potentially useful in versatile biomedical applications, particularly as suture support materials for surgical procedures.

Cyanoacrylate in Colorectal Surgery: Is It Safe?

Anastomotic leakage (AL) of a gastrointestinal (GI) anastomosis continues to be an important complication in GI surgery. Since its introduction more than 60 years ago, Cyanoacrylate (CA) has gained popularity in colorectal surgery to provide "prophylaxis" against AL. However, although in surgical practice it is increasingly used, evidence on humans is still lacking. The aim of this study is to analyze in humans the safety of CA to seal colorectal anastomosis. All consecutive patients from Jannuary 2022 through December 2022 who underwent minimally invasive colorectal surgery were retrospectively analyzed from a prospectively maintained database. Inclusion criteria were a histological diagnosis of cancer, a totally minimally invasive procedure, and the absence of intraoperative complications. 103 patients were included in the study; N-butyl cyanoacrylate with metacryloxisulfolane (Glubran 2®) was used to seal colorectal anastomosis, no adverse reactions to CA or postoperative complications related to inflammation and adhesions occurred; and only one case of AL (0.9%) was recorded. We can consider this study an important proof of concept on the safety of CA to seal colorectal anastomosis. It opens the possibility of starting prospective and comparative studies in humans to evaluate the effectiveness of CA in preventing colorectal AL.

The Impact of Phase-Specific Macrophage Depletion on Intestinal Anastomotic Healing

Intestinal anastomotic healing (AH) is critical in colorectal surgery, since disruptive AH leads to anastomotic leakage, a feared postoperative complication. Macrophages are innate immune cells and are instrumental in orchestrating intestinal wound healing, displaying a functional dichotomy as effectors of both tissue injury and repair. The aim of this study was to investigate the phase-specific function and plasticity of macrophages during intestinal AH. Transgenic CD11b diphtheria toxin receptor (CD11b-DTR) mice were used to deplete intestinal macrophages in a temporally controlled manner. Distal colonic end-to-end anastomoses were created in CD11b-DTR, and wild-type mice and macrophages were selectively depleted during either the inflammatory (day 0–3), proliferative (day 4–10), or reparative (day 11–20) phase of intestinal AH, respectively. For each time point, histological and functional analysis as well as gene set enrichment analysis (GSEA) of RNA-sequencing data were performed. Macrophage depletion during the inflammatory phase significantly reduced the associated inflammatory state without compromising microscopic AH. When intestinal macrophages were depleted during the proliferative phase, AH was improved, despite significantly reduced perianastomotic neoangiogenesis. Lastly, macrophages were depleted during the reparative phase and GSEA revealed macrophage-dependent pathways involved in collagen remodeling, cell proliferation, and extracellular matrix composition. However, AH remained comparable at this late timepoint. These results demonstrate that during intestinal AH, macrophages elicit phase-specific effects, and that therapeutic interventions must critically balance their dual and timely defined role.

Peritoneal cytokines as a predictor of colorectal anastomotic leaks on postoperative day 1: a systematic review and meta-analysis

BACKGROUND

Anastomotic leakage (AL) is a major complication of colorectal surgery resulting in morbidity, mortality and poorer quality of life. The early diagnosis of AL is challenging due to the poor positive predictive value of tests available and reliance on clinical presentation which may be delayed. The aim of this systematic review was to assess the applicability of peritoneal cytokine levels as an early predictive test of AL in postoperative colorectal cancer patients.

METHODS

A comprehensive literature search was performed from inception to January 2021, in MEDLINE and EMBASE databases using MeSH and non-MeSH terms in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies evaluating peritoneal cytokines in the context of AL were included in this review.

RESULTS

Two hundred ninety-two abstracts were screened, 30 full manuscripts evaluated, and 12 prospective studies were included. There were 8 peritoneal cytokines evaluated (interleukin [IL]-1β, IL-6, IL-8, IL-10, vascular endothelial growth factor [VEGF], tumour necrosis factor alpha [TNF alpha] and matrix metalloproteinase [MMP]2 and MMP9) between AL and non-AL groups on postoperative day 1. Those that included IL-6 (7 studies), IL-10 (4 studies), TNF alpha (6 studies) and MMP9 (2 studies) were included in the meta-analysis. IL-10 was the only cytokine in the meta-analysis that was significantly (p < 0.05) raised in drain fluid on postoperative day 1 in AL patients.

CONCLUSIONS

Peritoneal IL-10 was significantly raised on postoperative day 1 in patients who subsequently developed AL. This may be a useful early predictor of AL and aid in an earlier diagnosis for postoperative colorectal patients. The range of cytokines investigated within the literature is limited and from heterogeneous studies which suggests more research is needed.

Anastomotic healing in a rat model of peritonitis after non-steroidal anti-inflammatory drug administration

The tissue inflammatory response can influence the outcome of anastomotic healing. Anastomotic leakage represents a dreadful complication after gastrointestinal surgery, in particular sepsis and intra-abdominal infections impair the restorative process of colic anastomoses. It has been debated whether the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) is a risk factor for dehiscence, since many patients receive NSAIDs in the early postoperative period. Our aim was, for the first time, to analyze the morpho-functional effects of postoperative administration of two commonly used NSAIDs, Diclofenac and Ketorolac, on the healing process of colo-colic anastomoses constructed under condition of fecal peritonitis in a rat model. Sixty adult male rats underwent two surgical procedures: peritonitis induction and colo-colic anastomosis, and were divided into three groups: 20 rats received saline; 20 rats 4 mg/kg Diclofenac and 20 rats 5 mg/kg Ketorolac. We assessed anastomosis strength, morphological features of tissue wound healing, immunohistochemical metalloproteinase 9 (MMP9) expression and collagen deposition and content by Sirius red staining and hydroxyproline level. We found no significant difference in bursting pressure, collagen content and organization and morphological features between the groups, except a significantly reduced presence of inflammatory cells and MMP9 expression in the groups treated with NSAIDs. Our findings showed that Diclofenac and Ketorolac administration did not affect post-surgical healing and did not increase the leakage risk of colo-colic anastomoses during peritonitis.

Adipose-Derived Mesenchymal Stromal Cells Improve the Healing of Colonic Anastomoses Following High Dose of Irradiation Through Anti-Inflammatory and Angiogenic Processes

Cancer patients treated with radiotherapy (RT) could develop severe late side effects that affect their quality of life. Long-term bowel complications after RT are mainly characterized by a transmural fibrosis that could lead to intestinal obstruction. Today, surgical resection is the only effective treatment. However, preoperative RT increases the risk of anastomotic leakage. In this study, we attempted to use mesenchymal stromal cells from adipose tissue (Ad-MSCs) to improve colonic anastomosis after high-dose irradiation. MSCs were isolated from the subcutaneous fat of rats, amplified in vitro, and characterized by flow cytometry. An animal model of late radiation side effects was induced by local irradiation of the colon. Colonic anastomosis was performed 4 wk after irradiation. It was analyzed another 4 wk later (i.e., 8 wk after irradiation). The Ad-MSC-treated group received injections several times before and after the surgical procedure. The therapeutic benefit of the Ad-MSC treatment was determined by colonoscopy and histology. The inflammatory process was investigated using Fluorine-182-Fluoro-2-Deoxy-d-Glucose Positron Emission Tomography and Computed Tomography (¹⁸F-FDG-PET/CT) imaging and macrophage infiltrate analyses. Vascular density was assessed using immunohistochemistry. Results show that Ad-MSC treatment reduces ulcer size, increases mucosal vascular density, and limits hemorrhage. We also determined that 1 Ad-MSC injection limits the inflammatory process, as evaluated through ¹⁸F-FDG-PET-CT (at 4 wk), with a greater proportion of type 2 macrophages after iterative cell injections (8 wk). In conclusion, Ad-MSC injections promote anastomotic healing in an irradiated colon through enhanced vessel formation and reduced inflammation. This study also determined parameters that could be improved in further investigations.

Tannin-based adhesive for protection of colonic anastomosis in the open abdomen

This study was aimed to evaluate the effect of tannin acid- polyethylene glycol (TP) adhesive on the wound healing process of primary colonic anastomosis in the open abdomen (OA). Adhesion strength test, degradation and hemostatic ability of TP were investigated. In a rat model, after standard colonic anastomoses, rats were divided into three groups: OA group; OA + FG (fibrin glue) group; OA + TP group. Five days after surgery, body weight, anastomotic bursting pressure (ABP), and histology of anastomotic tissue were evaluated. Performance of adhesion strength and hemostatic ability of TP was better than that of FG. The weight of TP decreased by over 50% after 11-day incubation. All rats survived well after surgery. Compared to OA group and OA + FG group, OA + TP group showed a significant improvement in body weight, ABP and healing state. Application of TP adhesive, used as an auxiliary treatment of colonic anastomosis operation, improved the wound strength and promoted the anastomotic healing after OA.

Integrated approach to colorectal anastomotic leakage: Communication, infection and healing disturbances

Colorectal anastomotic leakage (CAL) remains a major complication after colorectal surgery. Despite all efforts during the last decades, the incidence of CAL has not decreased. In this review, we summarize the available strategies regarding prevention, prediction and intervention of CAL and categorize them into three categories: communication, infection and healing disturbances. These three major factors actively interact during the onset of CAL. We aim to provide an integrated approach to CAL based on its etiology. The intraoperative air leak test, intraoperative endoscopy, radiological examinations and stoma construction mainly aim to detect and to prevent communication between the intra- and extra-luminal content. Other strategies including postoperative drainage, antibiotics, and infectious-parameter evaluation are intended to detect and prevent anastomotic or peritoneal infection. Most currently available interventions for CAL focus on the control of communication and infection, while strategies targeting the healing disturbances such as lifestyle changes, oxygen therapy and evaluation of metabolic biomarkers still lack wide clinical application. This simplified categorization may contribute to an integrated understanding of CAL. We strongly believe that this integrated approach should be taken into consideration during clinical practice. An integrated approach to CAL could contribute to a better understanding of the etiology of CAL and eventually better patient outcome.

Sutureless closure of colonic defects with tissue adhesives: an in vivo study in the rat

BACKGROUND

Tissue adhesives (TAs) in gastrointestinal surgery are gradually gaining acceptance. Before implementation as colonic sealants, an evaluation of the sealing capability of a TA when in contact with fecal matter, as in a leaking anastomosis, is needed. In this study, we used clinically available TAs for the sutureless closure of colonic defects evaluating mechanical strength and tissue healing.

METHODS

A total of 160 rats were divided into 8 groups. Two .5-cm incisions were created, one in the proximal and another in the distal colon. Incisions were sealed with a TA: Histoacryl Flex, Bioglue, Dermabond, Tissucol, Duraseal Xact, gelatin-resorcinol-formaldehyde or Glubran 2. A control group was included in which the colonic defects were not sealed. Follow-up time was 3 or 10 days. Clinical complication rate, bursting pressure, and histopathologic analysis was included.

RESULTS

Leakage rates in the TA groups were highest for Duraseal Xact, Bioglue, and gelatin-resorcinol-formaldehyde at 3 and 10 days. The cyanoacrylates Glubran 2, Histoacryl Flex, and Omnex, and the fibrin glue Tissucol showed the lowest overall clinical complication rates while maintaining the highest bursting pressure at day 10. Histoacryl Flex exhibited significantly higher collagen formation at day 10 than the other TAs.

CONCLUSIONS

This experimental model evaluates the protective effect of a TA seal on a leaking colonic defect. We found large differences in leakage rates and inertness of the tested TAs. The cyanoacrylates Histoacryl Flex, Omnex, and Glubran 2 as well as the fibrin glue Tissucol demonstrated the lowest leakage rates and the most inert histopathologic profile while maintaining high mechanical strength.

Cytokines as Early Markers of Colorectal Anastomotic Leakage: A Systematic Review and Meta-Analysis

Purpose. Colorectal anastomotic leakage (CAL) is one of the most severe complications after colorectal surgery. This meta-analysis evaluates whether systemic or peritoneal inflammatory cytokines may contribute to early detection of CAL. Methods. Systematic literature search was performed in the acknowledged medical databases according to the PRISMA guidelines to identify studies evaluating systemic and peritoneal levels of TNF, IL-1β, IL-6, and IL-10 for early detection of CAL. Means and standard deviations of systemic and peritoneal cytokine levels were extracted, respectively, for patients with and without CAL. The meta-analysis of the mean differences was carried out for each postoperative day using Review Manager. Results. Seven articles were included. The meta-analysis was performed with 5 articles evaluating peritoneal cytokine levels. Peritoneal levels of IL-6 were significantly higher in patients with CAL compared to patients without CAL on postoperative days 1, 2, and 3 (P < 0.05). Similar results were found for peritoneal levels of TNF but on postoperative days 3, 4, and 5 (P < 0.05). The articles regarding systemic cytokine levels did not report any significant difference accordingly. Conclusion. Increased postoperative levels of peritoneal IL-6 and TNF are significantly associated with CAL and may contribute to its early detection.

Hyperbaric oxygen therapy improves colorectal anastomotic healing

PURPOSE

Hyperbaric oxygen treatment (HBOT) has been found to improve the healing of poorly oxygenated tissues. This study aimed to investigate the influence of HBOT on the healing in ischemic colorectal anastomosis.

METHODS

Forty Wistar rats were randomly divided into a treatment group that received HBOT for 10 consecutive days (7 days before and 3 days after surgery), or in a control group, which did not receive the therapy. Colectomy with an ischemic anastomosis was performed in all rats. In each group, the rats were followed for 3 or 7 days after surgery to determine the influence of HBOT on anastomotic healing.

RESULTS

Five rats from each group died during follow-up. No anastomotic dehiscence was seen in the HBOT group, compared to 37.5 % and 28.6 % dehiscence in the control group on postoperative day (POD) 3 and 7, respectively. The HBOT group had a significantly higher bursting pressure (130.9 ± 17.0 mmHg) than the control group (88.4 ± 46.7 mmHg; p = 0.03) on POD 3. On POD 3 and POD 7, the adhesion severity was significantly higher in the control groups than in the HBOT groups (p < 0.005). Kidney function (creatinine level) of the HBOT group was significantly better than of the control group on POD 7 (p = 0.001). Interestingly, a significantly higher number of CD206+ cells (marker for type 2 macrophages) was observed in the HBOT group at the anastomotic area on POD 3.

CONCLUSION

Hyperbaric oxygen enhanced the healing of ischemic anastomoses in rats and improved the postoperative kidney function.

Colorectal anastomotic healing: why the biological processes that lead to anastomotic leakage should be revealed prior to conducting intervention studies

BACKGROUND

Anastomotic leakage (AL) remains the most dreaded complication after colorectal surgery and causes high morbidity and mortality. The pathophysiology of AL remains unclear, despite numerous studies that have been conducted on animals and humans, probably due to the undetermined healing process of colorectal anastomoses. Increasing basic knowledge on this healing process may shed more light on causal factors of AL, and additionally reduce the quantity and accelerate the quality of experimental studies. In this debate article, our aim was to provide different perspectives on what is known about the colorectal healing process in relation to wound healing and AL.

DISCUSSION

Since knowledge on anastomotic healing is lacking, it remains difficult to conclude which factors are essential in preventing AL. This is essential information in the framework of humane animal research, where the focus should lie on Replacement, Reduction and Refinement (3Rs). While many researchers compare anastomotic healing with wound healing in the skin, there are substantial recognized differences, e.g. other collagen subtypes and different components involved. Based on our findings in literature as well as discussions with experts, we advocate stop considering anastomotic healing in the gastrointestinal tract and cutaneous healing as a similar process. Furthermore, intervention studies should at least address the anastomotic healing process in terms of histology and certain surrogate markers. Finally, the anastomotic healing process ought to be further elucidated - with modern techniques to achieve 3Rs in animal research--to provide starting points for potential interventions that can prevent AL.

Postoperative Hemodynamic Index Measurement With Miniaturized Dynamic Light Scattering Predicts Colorectal Anastomotic Healing

INTRODUCTION

Perioperative bowel perfusion (local hemodynamic index [LHI]) was measured with a miniaturized dynamic light scattering (mDLS) device, aiming to determine whether anastomotic perfusion correlates with the anastomotic healing process and whether LHI measurement assists in the detection of anastomotic leakage (AL) in colorectal surgery.

METHODS

A partial colectomy was performed in 21 male Wistar rats. Colonic and anastomotic LHIs were recorded during operation. On postoperative day (POD) 3, the rats were examined for AL manifestations. Anastomotic LHI was recorded before determining the anastomotic bursting pressure (ABP). The postoperative LHI measurements were repeated in 15 other rats with experimental colitis. Clinical manifestations and anastomotic LHI were also determined on POD3. Diagnostic value of LHI measurement was analyzed with the combined data from both experiments.

RESULTS

Intraoperative LHI measurement showed no correlation with the ABP on POD3. Postoperative anastomotic LHI on POD3 was significantly correlated with ABP in the normal rats (R(2) = 0.52; P < .001) and in the rats with colitis (R(2) = 0.63; P = .0012). Anastomotic LHI on POD3 had high accuracy for identifying ABP <50 mm Hg (Area under the curve = 0.86; standard error = 0.065; P < .001). A cutoff point of 1236 yielded a sensitivity of 100% and a specificity of 65%. On POD3, rats with LHIs <1236 had significantly higher dehiscence rates (40% vs 0%), more weight loss, higher abscess severity, and lower ABPs (P < .05); worse anastomotic inflammation and collagen deposition were also found in the histological examination.

CONCLUSION

Our data suggest that postoperative evaluation of anastomotic microcirculation with the mDLS device assists in the detection of AL in colorectal surgery.

Reducing colorectal anastomotic leakage with tissue adhesive in experimental inflammatory bowel disease

BACKGROUND

Anastomotic leakage after gastrointestinal surgery remains a challenging clinical problem. This study aimed to investigate the effectiveness of TissuCol (fibrin glue), Histoacryl Flex (n-butyl-2-cyanoacrylate), and Duraseal (polyethylene glycol) on colorectal anastomotic healing during experimental colitis.

METHODS

We first performed colectomy 7 days after 10 mg trinitrobenzene sulfonic acid (TNBS)-induced colitis to validate a rat TNBS-colitis-colectomy model. Subsequently, this TNBS-colitis-colectomy model was used in 73 Wistar rats that were stratified into a colitis group (CG, no adhesive), a TissuCol group (TG), a Histoacryl group (HG), and a Duraseal group (DG). Anastomotic sealant was applied with one adhesive after constructing an end-to-end hand-sewn anastomosis. Clinical manifestations, anastomotic bursting pressure, and immunohistochemistry of macrophage type-one (M1) and type-two (M2) was performed on postoperative day (POD)3 or POD7.

RESULTS

TNBS-caused mucosal and submucosal colon damage and compromised anastomotic healing (i.e., abscess formation and low anastomotic bursting pressure). On POD3, higher severity of abscesses was seen in CG. Average anastomotic bursting pressure was 53.2 ± 35.5 mm Hg in CG, which was significantly lower than HG (134.4 ± 27.5 mm Hg) and DG (95.1 ± 54.3 mm Hg) but not TG (83.4 ± 46.7 mm Hg). Furthermore, a significantly higher M2/M1 index was found in HG. On POD7, abscesses were only seen in CG (6/9) but not in other groups; HG had the lowest severity of adhesion.

CONCLUSIONS

We describe the first surgical IBD model by performing colectomy in rats with TNBS-induced colitis, which causes intra-abdominal abscess formation and compromises anastomotic healing. Anastomotic sealing with Histoacryl Flex prevents these complications in this model. Alternative activation of macrophages seems to be involved in its influence on anastomotic healing.