Adherence to fast track measures in colorectal surgery-a survey among German and Austrian surgeons.

PURPOSE: The effectiveness of modern perioperative treatment concepts has been demonstrated in several studies and meta-analyses. Despite good evidence, limited implementation of the fast track (FT) concept is still a widespread concern. To assess the status quo in Austrian and German hospitals, a survey on the implementation of FT measures was conducted among members of the German Society of General and Visceralsurgery (DGAV), the German Society of Coloproctology (DGK) and the Austrian Society of Surgery (OEGCH) to analyze where there is potential for improvement. METHODS: Twenty questions on perioperative care of colorectal surgery patients were sent to the members of the DGAV, DGK and OEGCH using the online survey tool SurveyMonkey®. Descriptive data analysis was performed using Microsoft Excel. RESULTS: While some of the FT measures have already been routinely adopted in clinical practice (e.g. minimally invasive surgical approach, early mobilization and diet buildup), for other components there are discrepancies between current recommendations and present implementation (e.g. the use of local nerve blocks to provide opioid-sparing analgesia or the use of abdominal drains). CONCLUSION: The implementation of the FT concept in Austria and Germany is still in need of improvement. Particularly regarding the use of abdominal drains and postoperative analgesia, there is a tendency to stick to traditional structures. To overcome the issues with FT implementation, the development of an evidence-based S3 guideline for perioperative care, followed by the founding of a surgical working group to conduct a structured education and certification process, may lead to significant improvements in perioperative patient care.

Treatment with the 5-Lipoxygenase Antagonist Zileuton Protects Mice from Postoperative Ileus.

INTRODUCTION: Previous work of our group showed that lipoxygenase (LOX) pathways become activated upon surgical manipulation of the bowel wall and revealed a beneficial immune modulating role of the LOX-derived anti-inflammatory mediator protectin DX in postoperative ileus (POI). While we found a particular role of 12/15-LOX in the anti-inflammatory LOX action during POI, the role of 5-LOX, which produces the pro-inflammatory leukotriene B4 (LTB4), remained unknown. The purpose of this study was to investigate the role of 5-LOX within the pathogenesis of POI in a mouse model. METHODS: POI was induced by intestinal manipulation (IM) of the small bowel in C57BL/6, 5-LOX-/-, and CX3CR1GFP/+. Mice were either treated with a vehicle or with the synthetic 5-LOX antagonist zileuton or were left untreated. Cellular localization of 5-LOX and LTB4 release were visualized by immunofluorescence or ELISA, respectively. POI severity was quantified by gastrointestinal transit (GIT) and leukocyte extravasation into the muscularis externa (ME) by immunohistochemistry. RESULTS: 5-LOX expression was detected 24 h after IM within infiltrating leukocytes in the ME. LTB4 levels increased during POI in wild type but not in 5-LOX-/- after IM. POI was ameliorated in 5-LOX-/- as shown by decreased leukocyte numbers and normalized GIT. Zileuton normalized the postoperative GIT and reduced the numbers of infiltrating leukocytes into the ME. DISCUSSION/CONCLUSION: Our data demonstrate that 5-LOX and its metabolite LTB4 play a crucial role in POI. Genetic deficiency of 5-LOX and pharmacological antagonism by zileuton protected mice from POI. 5-LOX antagonism might be a promising target for prevention of POI in surgical patients.

Update on surgical management of enteroatmospheric fistulae in intestinal failure patients.

PURPOSE OF REVIEW: The surgical management of enteroatmospheric fistula (EAF) in patients with intestinal failure represents a major challenge for a surgical team and requires proficiency in sepsis management, nutritional support and prehabilitation, beside expertise in visceral and abdominal wall surgery. This review provides an update on the current recommendations and evidence. RECENT FINDINGS: Reconstructive surgery should be performed at a minimum of 6-12 months after last laparotomy. Isolation techniques and new occlusion devices may accelerate spontaneous EAF closure in selected cases. Chyme reinfusion supports enteral and parenteral nutrition. Stapler anastomosis and failure to close the fascia increase the risk of EAF recurrence. Posterior component separation, intraoperative fascial tension and biological meshes may be used to accommodate fascial closure. SUMMARY: Timing of reconstructive surgery and previous optimal conservative treatment is vital for favorable outcomes. Wound conditions, nutritional support and general patient status should be optimal before attempting a definitive fistula takedown. Single stage procedures with autologous gut reconstruction and abdominal wall reconstruction can be complex but well tolerated.

Effect of transcutaneous vagus nerve stimulation on muscle activity in the gastrointestinal tract (transVaGa): a prospective clinical trial.

PURPOSE: Postoperative ileus (POI) is a common complication after abdominal surgery. Invasive stimulation of the cervical vagus nerve is known to reduce inflammatory response and ameliorated POI after surgery in a mouse model. However, the transcutaneous vagus nerve stimulation (tVNS) is a possible non-invasive approach. In this clinical study, we aimed to investigate the effect of tVNS on the activation of the stomach muscle in humans. METHODS: Patients requiring open laparotomy were screened for this prospective proof of concept clinical study. After open laparotomy, muscle activity of the stomach was measured by a free running electromyography (EMG) before and during tVNS on the ear. Frequency and amplitude of compound gastric action potentials were the electrophysiological parameters we assessed to reveal the changes in electro motor gastric activity. Gastrin levels as a surrogate marker for vagus nerve activation was analyzed before, 1 and 3 h after tVNS. RESULTS: Fourteen patients were included, no severe adverse events and no medical device related adverse events occurred. tVNS led to significant reduction of action potential frequency and significant elevation of action potential amplitude in the stomach compared to control. Gastrin levels were significantly elevated 3 h after tVNS compared to levels before tVNS. CONCLUSION: Application of tVNS is a safe and feasible procedure during surgical intervention. Our results provide evidence that tVNS activates efferent visceral vagal fibers. Therefore, this low risk and easy to perform method could be useful to prevent postoperative ileus. CLINICAL TRIAL REGISTER NUMBER: DRKS00013340.

Postoperative ileus involves interleukin-1 receptor signaling in enteric glia.

BACKGROUND & AIMS: Postoperative ileus (POI) is a common consequence of abdominal surgery that increases the risk of postoperative complications and morbidity. We investigated the cellular mechanisms and immune responses involved in the pathogenesis of POI. METHODS: We studied a mouse model of POI in which intestinal manipulation leads to inflammation of the muscularis externa and disrupts motility. We used C57BL/6 (control) mice as well as mice deficient in Toll-like receptors (TLRs) and cytokine signaling components (TLR-2(-/-), TLR-4(-/-), TLR-2/4(-/-), MyD88(-/-), MyD88/TLR adaptor molecule 1(-/-), interleukin-1 receptor [IL-1R1](-/-), and interleukin (IL)-18(-/-) mice). Bone marrow transplantation experiments were performed to determine which cytokine receptors and cell types are involved in the pathogenesis of POI. RESULTS: Development of POI did not require TLRs 2, 4, or 9 or MyD88/TLR adaptor molecule 2 but did require MyD88, indicating a role for IL-1R1. IL-1R1(-/-) mice did not develop POI; however, mice deficient in IL-18, which also signals via MyD88, developed POI. Mice given injections of an IL-1 receptor antagonist (anakinra) or antibodies to deplete IL-1α and IL-1ß before intestinal manipulation were protected from POI. Induction of POI activated the inflammasome in muscularis externa tissues of C57BL6 mice, and IL-1α and IL-1ß were released in ex vivo organ bath cultures. In bone marrow transplantation experiments, the development of POI required activation of IL-1 receptor in nonhematopoietic cells. IL-1R1 was expressed by enteric glial cells in the myenteric plexus layer, and cultured primary enteric glia cells expressed IL-6 and the chemokine monocyte chemotactic protein 1 in response to IL-1ß stimulation. Immunohistochemical analysis of human small bowel tissue samples confirmed expression of IL-1R1 in the ganglia of the myenteric plexus. CONCLUSIONS: IL-1 signaling, via IL-1R1 and MyD88, is required for development of POI after intestinal manipulation in mice. Agents that interfere with the IL-1 signaling pathway are likely to be effective in the treatment of POI.

Current knowledge on regulation and impairment of motility after intestinal transplantation.

PURPOSE OF REVIEW: Understanding the key mechanisms impacting on intestinal graft motility is paramount for successful intestinal transplantation. In this review, we will discuss causes of graft hypomotility and hypermotility, rooted in changes of the intrinsic nervous system, local inflammatory processes, adaptive immune responses, and more. RECENT FINDINGS: Recently, it has been shown that the gut microbiome closely interacts with the structural integrity and rejection processes in the small intestine. After the ischemia/reperfusion injury is overcome, the absence of rejection is important to maintain graft motor function. The interstitial cells of Cajal, with their pacemaker function, play an important role by regulating propulsive intestinal motility in the initial absence of extrinsic signaling. Local inflammatory and immunological changes in the tunica muscularis of transplanted intestines also result in dysmotility, both after ischemia/reperfusion and during rejection. SUMMARY: Motility of the transplanted intestine is crucial for transplant outcome and depends on multiple factors. Extrinsic denervation and changes in the intrinsic intestinal nervous system, local inflammation in the tunica muscularis, acute and chronic rejection, changes in the microbiome with Toll-like receptor activation, stasis of intestinal contents with bacterial translocation, all multifactorially result in impaired graft motility. These factors must be individually acknowledged and addressed to obtain adequate graft function.

First-Line Treatment for Advanced Hepatocellular Carcinoma: A Three-Armed Real-World Comparison.

Background and Aim: There are several existing systemic 1st- line therapies for advanced hepatocellular carcinoma (HCC), including atezolizumab/bevacizumab (Atez/Bev), sorafenib and lenvatinib. This study aims to compare the effectiveness of these three 1st-line systemic treatments in a real-world setting for HCC, focusing on specific patient subgroups analysis. Methods: A total of 177 patients with advanced HCC treated with Atez/Bev (n = 38), lenvatinib (n = 21) or sorafenib (n = 118) as 1st line systemic therapy were retrospectively analyzed and compared. Primary endpoints included objective response rate (ORR), progression-free survival (PFS) and 15-month overall survival (15-mo OS). Subgroups regarding liver function, etiology, previous therapy and toxicity were analyzed. Results: Atez/Bev demonstrated significantly longer median 15-month OS with 15.03 months compared to sorafenib with 9.43 months (p = 0.04) and lenvatinib with 8.93 months (p = 0.05). Similarly, it had highest ORR of 31.6% and longest median PFS with 7.97 months, independent of etiology. However, significantly superiority was observed only compared to sorafenib (ORR: 4.2% (p < 0.001); PFS: 4.57 months (p = 0.03)), but not comparing to lenvatinib (ORR: 28.6% (p = 0.87); PFS: 3.77 months (p = 0.10)). Atez/Bev also resulted in the longest PFS in patients with Child-Pugh A and ALBI 1 score and interestingly in those previously treated with SIRT. Contrary, sorafenib was non inferior in patients with impaired liver function. Conclusion: Atez/Bev achieved longest median PFS and 15-mo OS independent of etiology and particularly in patients with stable liver function or prior SIRT treatment. Regarding therapy response lenvatinib was non-inferior to Atez/Bev. Finally, sorafenib seemed to perform best for patients with deteriorated liver function.

Oral CPSI-2364 treatment prevents postoperative ileus in swine without impairment of anastomotic healing.

BACKGROUND: Postoperative ileus (POI) is an iatrogenic complication of abdominal surgery, mediated by a severe inflammation of the muscularis externa (ME). We demonstrated that orally applicated CPSI-2364 prevents POI in rodents by blockade of p38 MAPK pathway and abrogation of NO production in macrophages. In the present experimental swine study we compared the effect of orally and intravenously administered CPSI-2364 on POI and examined CPSI-2364 effect on anastomotic healing. METHODS: CPSI-2364 was administered preoperatively via oral or intravenous route. POI was induced by intestinal manipulation of the small bowel. ME specimens were examined by quantitative PCR for CCL2 chemokine gene expression and myeloperoxidase activity. Functional analyzes included measurement of ileal smooth-muscle ex vivo contractility, in vivo intestinal and colonic transit. Furthermore, anastomotic healing of a rectorectostomy after CPSI-2364 treatment was assessed by perianastomotic hydroxyproline concentration, a histochemically evaluated healing score and anastomotic bursting pressure (ABP). RESULTS: CPSI-2364 abolished inflammation of the ME and improved postoperative smooth muscle contractility and intestinal transit independently of its application route. Hydroxyproline concentration and ABP measurement revealed no wound healing disturbances after oral or intravenous CPSI-2364 treatment whereas histological scoring demonstrated delayed anastomotic healing after intravenous treatment. CONCLUSION: CPSI-2364 effectively prevents POI in swine independently of its application route. Impairment of anastomotic healing could be observed after intravenous but not oral preoperative CPSI-2364 treatment. Subsumed, an oral preoperative administration of CPSI-2364 appears to be a safe and efficient strategy for prophylaxis of POI.

A natural tetrahydropyrimidine, ectoine, ameliorates ischemia reperfusion injury after intestinal transplantation in rats.

BACKGROUND/AIMS: Ischemia reperfusion (I/R) injury after small bowel transplantation leads to inflammatory reactions and loss of structural integrity with subsequent graft contractile dysfunction in the early postoperative phase. The natural tetrahydropyrimidine ectoine (1-,4-,5-,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid; THP) protects the ileal mucosa and muscularis against effects of I/R injury in an experimental model of isolated graft reperfusion. The effects of THP treatment were evaluated in an established experimental intestinal transplant model. METHODS: Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (6 h cold ischemia time). Perioperative THP treatment (intraluminal/intravascular) groups were compared to vehicle-treated animals (after 3 and 24 h) and non-transplanted controls (n = 5/group). Park's score defined the effects of I/R injury. The infiltration of neutrophils, monocytes and macrophages, mRNA expression of IL-6 and TNF-α, serum levels of IL-6 and NO and smooth muscle contractility were evaluated. RESULTS: Improved graft outcome after intraluminal and intravascular THP treatment was defined by considerably ameliorated neutrophil infiltration and less histological signs of I/R injury (p ≤ 0.05). In the presence of THP, mRNA expression of IL-6 and TNF-α and IL-6 and NO serum levels were reduced and smooth muscle function was improved. CONCLUSION: THP treatment offers protection against the effects of I/R injury in intestinal transplantation in vivo, however, only as supplementary treatment option.

Immune mediators of postoperative ileus.

UNLABELLED: CLINICAL BACKGROUND: In all patients undergoing abdominal surgery, a transient phase of interruption of bowel motility, named postoperative ileus (POI) occurs. POI is often accepted as an unavoidable "physiological" response and a self-limiting complication after surgery although it has a significant impact on patient morbidity with prolonged hospitalization and increased costs. Annual economic burden has been estimated as much as US $1.47 billion in the USA (Iyer et al. in J Manag Care Pharm 15(6):485-494, 2009). PATHOPHYSIOLOGY: The pathophysiology has been elucidated within the last decades, demonstrating that both, neurogenic and inflammatory mechanisms are involved in response to the surgical trauma. It is now generally accepted that POI pathogenesis processes in two phases: a first neurogenic phase is accountable for the immediate postoperative impairment of bowel motility. This is followed by a second immunological phase that can last for days and mainly affects strength and length of POI. More recent findings demonstrate a bidirectional interaction between the nervous and the immune system, and this interaction significantly contributed to our present understanding of POI pathophysiology. Although nerval mechanisms have a significant impact in the early phase of POI, the contribution of the immune system and subsequently its manipulation has risen as the most promising strategy in prevention or treatment of the clinically relevant prolonged form of POI. AIMS: The present manuscript will give an update on the inflammatory responses, the involved cell types, and participating immune mediators in POI.

Preoperative short-term parenteral administration of polyunsaturated fatty acids ameliorates intestinal inflammation and postoperative ileus in rodents.

PURPOSE: Abdominal surgery results in an inflammation of the intestinal muscularis externa (ME), subsequently leading to postoperative ileus (POI). Polyunsaturated fatty acids (PUFA) are known to modulate inflammation. The aim of this study was to analyze the effect of preoperative parenteral administration of marine (n-3) or soybean (n-6) PUFA lipid emulsions (PUFA-LE) on POI and tissue fatty acid profiles. METHODS: Rodents underwent intestinal manipulation (IM) after 5 days of parenteral administration of 10-mL/kg body weight saline, (n-3), or (n-6) PUFA-LE. Sham animals received saline treatment without IM. In rats, postoperative inflammation was quantified by ME neutrophil levels and NO production in organ culture, and ME function was determined by an in vitro contractility measurement. Additionally, in vivo gastrointestinal transit (GIT) was analyzed in mice. Lipopolysaccharide-induced IL-6 expression of rat bone marrow-derived mononuclear cells and ME was analyzed. Fatty acids were measured by gas chromatography in rat blood, bone marrow cells, and ME. RESULTS: The (n-3) PUFA-LE reduced neutrophil levels and NO production after IM and improved in vitro jejunal contractility and GIT time. The (n-6) PUFA-LE significantly reduced postoperative inflammation and tended to improve intestinal motility (P < 0.06). Interestingly, (n-6) PUFA-LE significantly reduced the levels of arachidonic acid in ME (-63%), while (n-3) PUFA-LE reduced arachidonic acid (-20%) and additionally raised EPA (+550%). CONCLUSION: Short-term preoperative parenteral administration of (n-3) or (n-6) PUFA-LE significantly alters tissue-specific fatty acid profiles. Preoperative parenteral PUFA-LE supplementation, preferably by marine (n-3) PUFA, ameliorates postoperative intestinal inflammation and dysmotility and could be a promising therapeutic option in POI prophylaxis.

Don't fear the (small) bite: A narrative review of the rationale and misconceptions surrounding closure of abdominal wall incisions.

Background: The most common complications related to the closure of abdominal wall incisions are surgical site infections, wound dehiscence and the development of an incisional hernia. Several factors relating to the surgical technique and the materials used have been identified and analysed over the years, as mirrored in the current recommendations of the European Hernia Society, but some misconceptions still remain that hinder wide implementation. Method: A literature search was performed in the PubMed and GoogleScholar databases on 15 July 2021 and additionally on 30 March 2022 to include recent updates. The goal was to describe the scientific background behind the optimal strategies for reducing incisional hernia risk after closure of abdominal wall incisions in a narrative style review. Results: An aponeurosis alone, small bites/small steps continuous suture technique should be used, using a slowly resorbable USP 2/0 or alternatively USP 0 suture loaded in a small ½ circle needle. The fascial edges should be properly visualised and tension should be moderate. Conclusion: Despite the reproducibility, low risk and effectiveness in reducing wound complications following abdominal wall incisions, utilisation of the recommendation of the guidelines of the European Hernia Society remain relatively limited. More work is needed to clear misconceptions and disseminate the established knowledge and technique especially to younger surgeons.

Colonic anastomotic healing in the context of altered macrophage function and endotoxemia.

PURPOSE: Prevention of perioperative activation of intestinal muscularis macrophages is a promising intervention to avoid post-traumatic gastrointestinal tract dysfunction. However, impaired macrophage function could have deleterious consequences on anastomotic healing, especially in complications aggravating the healing process itself, such as infectious problems either as preexisting local inflammation or infection (e.g., complicated diverticulitis) or endotoxemia due to early postoperative infections (e.g., pneumonia). Aim of this study was to investigate colonic anastomotic healing in macrophage-depleted mice in the presence of endotoxemia. METHODS: Colonic anastomoses were performed, and mice were randomized into six groups (wild type; wild type with endotoxemia; pharmacological depletion of macrophages; pharmacological depletion with endotoxemia; genetically conditioned within the gut muscularis macrophage-deficient osteopetrotic mice; osteopetrotic mice with endotoxemia). Anastomotic tissues were removed 2, 5, and 10 days after surgery and used for functional, histological, biochemical, and molecular investigations. RESULTS: After pharmacological pretreatment, an almost complete depletion of macrophages was found in the muscularis up to 24 h postoperatively. Bursting pressure was significantly lower than 10 days after anastomotic procedure in osteopetrotic mice during endotoxemia, in marked contrast to transient pharmacologically macrophage-depleted mice. Pharmacological depletion during endotoxemia did not affect hydroxyproline concentration. Finally, in osteopetrotic mice during endotoxemia, collagen-3 expression was significantly lower compared to controls. CONCLUSIONS: In our current model, we demonstrate that perioperative pharmacological macrophage depletion and inactivation transiently diminishes muscularis macrophages and does not affect intestinal anastomotic healing in the presence of endotoxemia. However, a long-lasting macrophage absence or dysfunction impairs anastomotic healing and could be a risk factor for postoperative anastomotic leakage.

Mechanical strain and TLR4 synergistically induce cell-specific inflammatory gene expression in intestinal smooth muscle cells and peritoneal macrophages.

Mechanical trauma of the gut is an unavoidable event in abdominal surgery. Former studies demonstrated that intestinal manipulation induces a strong inflammation within the tunica muscularis. We hypothesized that mechanical strain initiates or aggravates proinflammatory responses in intestinal smooth muscle cells (iSMC) or macrophages. First, an appropriate isolation and culture method for neonatal rat iSMC was established. Purified iSMC and primary peritoneal macrophages (pMacs) were subjected to static or cyclic strain, and gene expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), IL-6, and IL-1ß was analyzed by quantitative PCR. Supernatants from stretched iSMC were transferred to untreated pMacs or contrariwise, and medium transfer-triggered inflammatory gene expression was measured in unstretched cells. Finally, we investigated the synergistic effect of static strain on LPS-induced proinflammatory gene expression. Although cyclic strain failed, static strain significantly induced iNOS, COX-2, and IL-1ß mRNA in iSMC. pMacs showed an increase in all inflammatory genes investigated as well as macrophage inflammatory protein (MIP)-1α and MIP-2 mRNA after static strain. Both cell entities liberated unknown mediators in response to stretch that mutually stimulated iNOS gene expression. Finally, mechanostimulation amplified LPS-induced iNOS and IL-1ß gene expression in iSMC as well as COX-2 and IL-6 mRNA in pMacs. In conclusion, static strain initiates proinflammatory gene expression in iSMC and pMacs and triggers a bidirectional paracrine communication between both cultured cell entities via the liberation of unknown mediators. Furthermore, static strain synergistically operates with Toll-like receptor 4 ligation in a cell-specific manner. Hence, this study demonstrates that mechanical strain functions as an immunomodulatory stimulus in abdominal cells.

Inhibition of p38 mitogen-activated protein kinase pathway as prophylaxis of postoperative ileus in mice.

BACKGROUND & AIMS: Postoperative ileus, an iatrogenic complication of abdominal surgery, is mediated by severe inflammation of the tunica muscularis. Macrophages that reside in the muscularis have important roles in initiating the inflammation. We investigated whether activation of the p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase is involved in the genesis of postoperative ileus, and whether p38-MAPK inhibition by the macrophage-specific inhibitor semapimod prevents intestinal dysmotility. METHODS: Postoperative ileus was induced by intestinal manipulation of the small bowel in mice. Protein kinase phosphorylation was assessed by immunoblotting of muscularis externa preparations. Proinflammatory gene expression was quantified by real-time polymerase chain reaction. Myeloperoxidase histochemistry for neutrophils was performed in jejunal segments. Nitric oxide production was measured by Griess reaction in smooth-muscle organ culture supernatants. Jejunal contractility was assessed within an organ bath setup. Intestinal motility was analyzed by gastrointestinal and colonic transit measurements. RESULTS: High levels of p38-MAPK and stress-activated protein kinase phosphorylation were observed immediately after intestinal manipulation. Semapimod treatment led to a significant decrease of p38-MAPK phosphorylation in macrophages; proinflammatory gene expression of macrophage inflammatory protein-1alpha, interleukin-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule-1; and neutrophil infiltration. Furthermore, semapimod completely abrogated nitric oxide production within the tunica muscularis. Subsequently, semapimod prevented the suppression of smooth muscle contractility and small intestinal and colonic motility after intestinal manipulation. CONCLUSION: A single preoperative semapimod administration prevents intestinal macrophage activation and subsequent gastrointestinal dysmotility induced by abdominal surgery. Semapimod inhibits p38-MAPK and nitric oxide production in macrophages, making it a promising strategy for prophylaxis of postoperative ileus.

The effect of sealing with a fixed combination of collagen matrix-bound coagulation factors on the healing of colonic anastomoses in experimental high-risk mice models.

PURPOSE: Experimental and clinical studies on the sealing of colorectal anastomoses in order to reduce the rate of leakage have previously been performed with divergent results. However, comparatively few studies have been performed on anastomotic healing using a fibrin glue-coated patch. The aim of this experimental basic scientific study in mice was to investigate the effect of fibrin glue-coated collagen patches on the healing process of colonic anastomoses in situations of adverse healing process (technical deficiency and peritonitis). METHODS: Colonic anastomoses were carried out in 206 mice and randomized into six groups (I: complete anastomoses, II: sealed complete anastomoses, III: incomplete anastomoses, IV: sealed incomplete anastomoses, V: complete anastomoses in the presence of bacterial peritonitis, VI: sealed complete anastomoses in the presence of bacterial peritonitis). Tissues from the anastomoses were removed and used for functional, histochemical, molecular, and biochemical investigations. RESULTS: The evaluation of postoperative course data revealed the beneficial effect of additional sealing with a fixed combination of collagen matrix-bound coagulation factors I and IIa (Tachosil(®), Nycomed Austria, Linz) in high-risk experimental anastomotic healing. Sealing incomplete anastomoses resulted in significantly lower lethality and leakage rates, as well as significantly higher bursting pressure values and histopathologic scores. Collagen 1 and 3 expressions and hydroxyproline concentrations are greatly increased with additional sealing in all high-risk anastomoses. CONCLUSIONS: In our current model, we demonstrate that additionally sealing high-risk experimental colonic anastomoses provides a positive effect on the healing process. The effect on the molecular level in particular seems to be essential and requires further experimental studies to evaluate the mechanism.

Risk Factors for Postoperative Morbidity and Mortality after Small Bowel Surgery in Patients with Cirrhotic Liver Disease-A Retrospective Analysis of 76 Cases in a Tertiary Center.

(1) Purpose: As it is known, patients with liver cirrhosis (LC) undergoing colon surgery or hernia surgery have high perioperative morbidity and mortality. However, data about patients with LC undergoing small bowel surgery is lacking. This study aimed to analyze the morbidity and mortality of patients with LC after small bowel surgery in order to determine predictive risk factors for a poor outcome. (2) Methods: A retrospective analysis was performed of all patients undergoing small bowel surgery between January 2002 and July 2018 and identified 76 patients with LC. Postoperative complications were analyzed using the classification of Dindo/Clavien (D/C) and further subdivided (hemorrhage, pulmonary complication, wound healing disturbances, renal failure). A total of 38 possible predictive factors underwent univariate and multivariate analyses for different postoperative complications and in-hospital mortality. (3) Results: Postoperative complications [D/C grade ≥ II] occurred in 90.8% of patients and severe complications (D/C grade ≥ IIIB) in 53.9% of patients. Nine patients (11.8%) died during the postoperative course. Predictive factors for overall complications were "additional surgery" (OR 5.3) and "bowel anastomosis" (OR 5.6). For postoperative mortality, we identified the model of end-stage liver disease (MELD) score (OR 1.3) and portal hypertension (OR 5.8) as predictors. The most common complication was hemorrhage, followed by pulmonary complications, hydropic decompensation, renal failure, and wound healing disturbances. The most common risk factors for those complications were portal hypertension (PH), poor liver function, emergency or additional surgery, ascites, and high ASA score. (4) Conclusions: LC has a devastating influence on patients' outcomes after small bowel resection. PH, poor liver function, high ASA score, and additional or emergency surgery as well as ascites were significant risk factors for worse outcomes. Therefore, PH should be treated before surgery whenever possible. Expansion of the operation should be avoided whenever possible and in case of at least moderate preoperative ascites, the creation of an anastomotic ostomy should be evaluated to prevent leakages.

Chronic rejection after intestinal transplantation: A systematic review of experimental models.

Intestinal transplantation (ITX) constitutes a salvage treatment for irreversible intestinal failure and failure of parenteral nutrition. Chronic rejection (CR) remains the key obstacle for long-term intestinal graft survival but the pathomechanisms are incompletely understood. This study systematically reviews experimental models addressing CR after ITX in order to summarize current knowledge on CR pathogenesis and identify promising experimental strategies. A systematic literature search was conducted in line with the PRISMA guidelines, and 68 out of 677 articles qualified for the final analysis. The average methodological quality of the studies was suboptimal with 7 out of 11 points as assessed by a modified Oxford Centre for Evidence-Based Medicine score. Histology of the chronically rejected graft was almost universally integrated as outcome parameter but we found significant heterogeneity in utilized transplant techniques, organ preservation, immunosuppression and time points of CR-assessment. Several studies identified cellular and humoral immunologic mechanisms in chronic intestinal rejection. Yet, neither preventive nor therapeutic strategies against CR have been successfully introduced into human intestinal transplantation highlighting the persistent need for optimized experimental models. In this review, we aim to improve the translational value of forthcoming investigations on CR by discussing the experimental status quo and potential innovative approaches.

Non-invasive transcutaneous auricular vagus nerve stimulation prevents postoperative ileus and endotoxemia in mice.

BACKGROUND: The cholinergic anti-inflammatory pathway comprises the perception of peripheral inflammation by afferent sensory neurons and reflex activation of efferent vagus nerve activity to regulate inflammation. Activation of this pathway was shown to reduce the inflammatory response and improve outcome of postoperative ileus (POI) and sepsis in rodents. Herein, we tested if a non-invasive auricular electrical transcutaneous vagus nerve stimulation (tVNS) affects inflammation in models of POI or endotoxemia. METHODS: Mice underwent tVNS or sham stimulation before and after induction of either POI by intestinal manipulation (IM) or endotoxemia by lipopolysaccharide administration. Some animals underwent a preoperative right cervical vagotomy. Neuronal activation of the solitary tract nucleus (NTS) and the dorsal motor nucleus of the vagus nerve (DMV) were analyzed by immunohistological detection of c-fos+ cells. Gene and protein expression of IL-6, MCP-1, IL-1ß as well as leukocyte infiltration and gastrointestinal transit were analyzed at different time points after IM. IL-6, TNFα, and IL-1ß serum levels were analyzed 3 hours after lipopolysaccharide administration. RESULTS: tVNS activated the NTS and DMV and reduced intestinal cytokine expression, reduced leukocyte recruitment to the manipulated intestine segment, and improved gastrointestinal transit after IM. Endotoxemia-induced IL-6 and TNF-α release was also reduced by tVNS. The protective effects of tVNS on POI and endotoxemia were abrogated by vagotomy. CONCLUSION: tVNS prevents intestinal and systemic inflammation. Activation of the DMV indicates an afferent to efferent central circuitry of the tVNS stimulation and the beneficial effects of tVNS depend on an intact vagus nerve. tVNS may become a non-invasive approach for treatment of POI.

Intestinal manipulation affects mucosal antimicrobial defense in a mouse model of postoperative ileus.

AIM: To explore the effects of abdominal surgery and interleukin-1 signaling on antimicrobial defense in a model of postoperative ileus. METHODS: C57BL/6 and Interleukin-1 receptor type I (IL-1R1) deficient mice underwent intestinal manipulation to induce POI. Expression of mucosal IL-1α, IL-1ß and IL-1R1 and several antimicrobial peptides and enzymes were measured by quantitative PCR or ELISA, western blotting or immunohistochemistry. Bacterial overgrowth was determined by fluorescent in-situ hybridization and counting of jejunal luminal bacteria. Translocation of aerobic and anaerobic bacteria into the intestinal wall, mesenteric lymph nodes, liver and spleen was determined by counting bacterial colonies on agar plates 48h after plating of tissue homogenates. Antimicrobial activity against E. coli and B. vulgatus was analyzed in total and cationic fractions of small bowel mucosal tissue homogenates by a flow cytometry-based bacterial depolarization assay. RESULTS: Jejunal bacterial overgrowth was detected 24h after surgery. At the same time point, but not in the early phase 3h after surgery, bacterial translocation into the liver and mesenteric lymph nodes was observed. Increased antimicrobial activity against E. coli was induced within early phase of POI. Basal antimicrobial peptide and enzyme gene expression was higher in the ileal compared to the jejunal mucosa. The expression of lysozyme 1, cryptdin 1, cryptdin 4 and mucin 2 were reduced 24h after surgery in the ileal mucosa and mucin 2 was also reduced in the jejunum. Postoperative IL-1α and IL-1ß were increased in the postoperative mucosa. Deficiency of IL-1R1 affected the expression of antimicrobial peptides during homeostasis and POI. CONCLUSION: Small bowel antimicrobial capacity is disturbed during POI which is accompanied by bacterial overgrowth and translocation. IL-1R1 is partially involved in the gene expression of mucosal antimicrobial peptides. Altered small bowel antimicrobial activity may contribute also to POI development and manifestation in patients undergoing abdominal surgery.