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Purpose Surgery initiates pro-inflammatory mediator cascades leading to a variably pronounced sterile inflammation (SIRS). SIRS is associated with intestinal paralysis and breakdown of intestinal barrier and might result in abdominal sepsis. Technological progress led to the development of a neurostimulator for transcutaneous auricular vagal nerve stimulation (taVNS), which is associated with a decline in inflammatory parameters and peristalsis improvement in rodents and healthy subjects via activation of the cholinergic anti-inflammatory pathway. Therefore, taVNS might be a strategy for SIRS prophylaxis. Methods The NeuroSIRS-Study is a prospective, randomized two-armed, sham-controlled, double-blind clinical trial. The study is registered at DRKS00016892 (09.07.2020). A controlled endotoxemia is used as a SIRS-mimicking model. 2 ng/kg bodyweight lipopolysaccharide (LPS) will be administered after taVNS or sham stimulation. The primary objective is a reduction of clinical symptoms of SIRS after taVNS compared to sham stimulation. Effects of taVNS on release of inflammatory cytokines, intestinal function, and vital parameters will be analyzed. Discussion TaVNS is well-tolerated, with little to no side effects. Despite not fully mimicking postoperative inflammation, LPS challenge is the most used experimental tool to imitate SIRS and offers standardization and reproducibility. The restriction to healthy male volunteers exerts a certain bias limiting generalizability to the surgical population. Still, this pilot study aims to give first insights into taVNS as a prophylactic treatment in postoperative inflammation to pave the way for further clinical trials in patients at risk for SIRS. This would have major implications for future therapeutic approaches.

Purpose Postoperative Ileus (POI) remains an important complication for patients after abdominal surgery with an incidence of 10–27% representing an everyday issue for abdominal surgeons. It accounts for patients’ discomfort, increased morbidity, prolonged hospital stays, and a high economic burden. This review outlines the current understanding of POI pathophysiology and focuses on preventive treatments that have proven to be effective or at least show promising effects. Methods Pathophysiology and recommendations for POI treatment are summarized on the basis of a selective literature review. Results While a lot of therapies have been researched over the past decades, many of them failed to prove successful in meta-analyses. To date, there is no evidence-based treatment once POI has manifested. In the era of enhanced recovery after surgery or fast track regimes, a few approaches show a beneficial effect in preventing POI: multimodal, opioid-sparing analgesia with placement of epidural catheters or transverse abdominis plane block; μ-opioid-receptor antagonists; and goal-directed fluid therapy and in general the use of minimally invasive surgery. Conclusion The results of different studies are often contradictory, as a concise definition of POI and reliable surrogate endpoints are still absent. These will be needed to advance POI research and provide clinicians with consistent data to improve the treatment strategies.

Introduction: Postoperative ileus (POI) is a common complication after abdominal surgery. Until today, an evidence-based treatment of prolonged POI is still lacking, which can be attributed to the poor quality of clinical trials. Various different surrogate markers used to define POI severity are considered to be the cause of low-quality trials making it impossible to derive treatment recommendation. The SmartPill®, which is able to record pH values, temperature and pressure after ingestion, could be an ideal tool to measure transit times and peristalsis and therefore analyze POI severity. Unfortunately, the device has no approval for postoperative use due to safety concerns. The primary objective of the study is to determine safety of the SmartPill® in patients undergoing surgery. Secondary objectives were the quality of the recorded data and the suitability of the SmartPill® for analyzing intestinal motility after different surgical procedures. Methods: The PIDuSA Study is a prospective, 2-arm, open-label trial. At the end of surgery, the SmartPill® was applied to 49 patients undergoing abdominal surgery having a high risk for impaired intestinal motility and 15 patients undergoing extra-abdominal surgery. Patients were visited daily to access safety data of the SmartPill® on the basis of adverse and serious adverse events (AEs/SAEs). Suitability and data quality were investigated by analyzing data completeness and feasibility to determine transit times and peristalsis for all sections of the gastrointestinal tract. Results: In total, 179 AEs and 8 SAEs were recorded throughout the study affecting 42 patients in the abdominal (158 AEs) and 9 patients in the extra-abdominal surgery group (21 AEs, p = 0.061); none of them were device related. Primary capsule failure was observed in 5 patients, ultimately resulting in an impossibility of data analysis in only 3 patients (4.4%). 9% of the recorded data were incomplete due to the patient’s incompliance in keeping the receiver close to the body. In 3 patients (4.4%), isolated small bowel transit could not be determined due to pH alterations as a result of prolonged POI. Discussion: Our study demonstrates that the use of the SmartPill® is safe after surgery but requires a reasonable patient compliance to deliver meaningful data. An objective analysis of transit times and peristalsis was possible irrespective of type and site of surgery in over 95% indicating that the SmartPill® has the potential to deliver objective parameters for POI severity in future clinical trials. However, in some patients with prolonged POI, analysis of small bowel transit could be challenging.

Background: Liver cirrhosis is a relevant comorbidity with increasing prevalence. Postoperative decompensation and development of complications in patients with cirrhosis remains a frequent clinical problem. Surgery has been discussed as a precipitating event for decompensation and complications of cirrhosis, but the underlying pathomechanisms are still obscure. The aim of this study was to analyze the role of abdominal extrahepatic surgery in cirrhosis on portal pressure and fibrosis in a preclinical model.Methods: Compensated liver cirrhosis was induced using tetrachlormethane (CCL4) inhalation and bile duct ligation (BDL) models in rats, non-cirrhotic portal hypertension by partial portal vein ligation (PPVL). Intestinal manipulation (IM) as a model of extrahepatic abdominal surgery was performed. 2 and 7 days after IM, portal pressure was measured in-vivo. Hydroxyproline measurements, Sirius Red staining and qPCR measurements of the liver were performed for evaluation of fibrosis development and hepatic inflammation. Laboratory parameters of liver function in serum were analyzed.Results: Portal pressure was significantly elevated 2 and 7 days after IM in both models of cirrhosis. In the non-cirrhotic model the trend was the same, while not statistically significant. In both cirrhotic models, IM shows strong effects of decompensation, with significant weight loss, elevation of liver enzymes and hypoalbuminemia. 7 days after IM in the BDL group, Sirius red staining and hydroxyproline levels showed significant progression of fibrosis and significantly elevated mRNA levels of hepatic inflammation compared to the respective control group. A progression of fibrosis was not observed in the CCL4 model.Conclusion: In animal models of cirrhosis with continuous liver injury (BDL), IM increases portal pressure, and development of fibrosis. Perioperative portal pressure and hence inflammation processes may be therapeutic targets to prevent post-operative decompensation in cirrhosis.

Abdominal surgery results in an activation of immune cells of the bowel wall and a consecutive cytokine and nitric oxide (NO) release leading to an inflammation of the muscularis externa and a bowel paralysis, the so-called postoperative ileus (POI). In addition to the local inflammation, major surgical trauma can also lead to a variable pronounced systemic inflammation up to its maximum variant, the systemic inflammatory response syndrome (SIRS), with hypotension, capillary leak and a breakdown of the intestinal barrier function followed by multi-organ dysfunction (MODS). Until now, neither for SIRS nor for POI, a prophylaxis or an evidence-based treatment exists. Since the pioneering work from Kevin Tracey and his group in the late 90s characterizing the role of the vagus nerve in inflammation and describing the cholinergic anti-inflammatory pathway (CAIP) for the first time, substantial efforts have been made in the research field of neuro-immune interactions. Today, the anti-inflammatory potential of vagus nerve stimulation is moving more and more into focus resulting in new therapeutic approaches. This review focuses on the role of the CAIP in the development of SIRS and POI. Furthermore, new therapeutic options like transcutaneous vagus nerve stimulation are highlighted.

Interactions between the peripheral nervous system and resident macrophages (MMs) modulate intestinal homeostatic functions. Activation of β2-adrenergic receptors on MMs has been shown to reduce bacterial challenges. These MMs are also crucial for the development of bowel inflammation in postoperative ileus (POI), an iatrogenic, noninfectious inflammation-based motility disorder. However, the role of the sympathetic nervous system (SNS) in the immune modulation of these MMs during POI or other noninfectious diseases is largely unknown. By employing 6-OHDA-induced denervation, we investigated the changes in the muscularis externa by RNA-seq, quantitative PCR, and flow cytometry. Further, we performed transcriptional phenotyping of sorted CX3CR1+ MMs and ex vivo LPS/M-CSF stimulation on these MMs. By combining denervation with a mouse POI model, we explored distinct changes on CX3CR1+ MMs as well as in the muscularis externa and their functional outcome during POI. Our results identify SNS as an important mediator in noninfectious postoperative inflammation. Upon denervation, MMs anti-inflammatory genes were reduced, and the muscularis externa profile is shaped toward a proinflammatory status. Further, denervation reduced MMs anti-inflammatory genes also in the early phase of POI. Finally, reduced leukocyte infiltration into the muscularis led to a quicker recovery of bowel motility in the late phase of POI.

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation (tVNS) across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation(VNS) and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice. ispartof: Frontiers In Human Neuroscience vol:14 pages:1-47 ispartof: location:Switzerland status: published

Postoperative ileus (POI) is triggered by an innate immune response in the muscularis externa (ME) and is accompanied by bacterial translocation. Bacteria can trigger an innate immune response via toll-like receptor (TLR) activation, but the latter’s contribution to POI has been disproved for several TLRs, including TLR2 and TLR4. Herein we investigated the role of double-stranded RNA detection via TLR3 and TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling pathway in POI. POI was induced by small bowel intestinal manipulation in wt, TRIF-/-, TLR3-/-, type I interferon receptor-/- and interferon-β reporter mice, all on C57BL/6 background, and POI severity was quantified by gene expression analysis, gastrointestinal transit and leukocyte extravasation into the ME. TRIF/TLR3 deficiency reduced postoperative ME inflammation and prevented POI. With bone marrow transplantation, RNA-sequencing, flow cytometry and immunohistochemistry we revealed a distinct TLR3-expressing radio-resistant MHCIIhiCX3CR1- IBA-1+ resident macrophage population within the deep myenteric plexus. TLR3 deficiency in these cells, but not in MHCIIhiCX3CR1+ macrophages, reduced cytokine expression in POI. While this might not be an exclusive macrophage-privileged pathway, the TLR3/TRIF axis contributes to proinflammatory cytokine production in MHCIIhiCX3CR1- IBA-1+ macrophages during POI. Deficiency in TLR3/TRIF protects mice from POI. These data suggest that TLR3 antagonism may prevent POI in humans.

Postoperative ileus (POI) is an intestinal dysmotility frequently occurring after abdominal surgery. An orchestrated neuroimmune response within the muscularis externa (ME) involves activation of resident macrophages, enteric glia and infiltration of blood-derived leukocytes. Interleukin-1 receptor type-I (IL1R1) signalling on enteric glia has been shown to be involved in POI development. Herein we investigated the distinct role of the IL1R1 ligands interleukin (IL) -1α and IL-1β and focused on the mechanism of IL-1β production. IL-1α and IL-1β deficient mice were protected from POI. Bone-marrow transplantation studies indicated that IL-1α originated from radio-resistant cells while IL-1β was released from the radio-sensitive infiltrating leukocytes. Mouse strains deficient in inflammasome formation identified the absent in melanoma 2 (AIM2) inflammasome to be crucial for IL-1β production in POI. Mechanistically, antibiotic-treated mice revealed a prominent role of the microbiome in IL-1β production. Our study provides new insights into distinct roles of IL-1α and IL-1β signalling during POI. While IL-1α release is most likely an immediate passive response to the surgical trauma, IL-1β production depends on AIM2 inflammasome formation and the microbiome. Selective interaction in this pathway might be a promising target to prevent POI in surgical patients.

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. 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. 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. 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. DRKS00013340.

// Azin Jafari 1 , Hanno Matthaei 1 , Sven Wehner 1 , Tolga Tonguc 1 , Jorg C. Kalff 1 and Steffen Manekeller 1 1 Department of Surgery, University Hospital Bonn, Germany Correspondence to: Steffen Manekeller, email: steffen.manekeller@ukb.uni-bonn.de Keywords: SOS; sinusoidal obstruction syndrome; bevacizumab; colorectal cancer; CRC Received: December 21, 2017 Accepted: March 17, 2018 Published: April 24, 2018 ABSTRACT Background: Thanks to modern multimodal treatment the ouctome of patients with colorectal cancer has experienced significant improvements. As a downside, agent specific side effects have been observed such as sinusoidal obstruction syndrome (SOS) after oxaliplatin chemotherapy (OX). Bevazicumab targeting VEGF is nowadays comprehensively used in combination protocols with OX but its impact on hepatotoxicity is thus far elusive and focus of the present study. Results: After MCT administration 67% of animals developed SOS. GOT serum concentration significantly increased in animals developing SOS ( p < 0.001). Subsequent to MCT administration 100% of animals treated with Anti-VEGF developed SOS. In contrast, animals receiving VEGF developed SOS merely in 40% while increasing the VEGF dose led to a further decrease in SOS development to 25%. MMP 9 concentration in animals developing SOS was significantly higher compared to controls ( p < 0,001). Additional treatment with Anti-VEGF increased the MMP 9 concentration significantly ( p < 0,05). Conclusions: Preservation of liver function is a central goal in both curative and palliative treatment phases of patients with CRC. Thus, knowledge about hepatotoxic side effects of chemotherapeutic and biological agents is crucial. From the results it can be concluded that Anti-VEGF exacerbates SOS paralleled by MMP 9 production. Therefore, OX-Bevacizumab combination therapies should be administered with caution, especially if liver parenchyma damage is apparent. Methods: Male Sprague-Dawley rats were gavaged Monocrotaline (MCT) to induce SOS. Recombinant VEGF or an Anti-VEGF antibody was administered to MCT-treated rats and the hepatotoxic effect monitored in defined time intervals. MMP 9 expression in the liver was measured by ELISA.

Postoperative ileus (POI) is an intestinal dysmotility frequently occurring after abdominal surgery. An orchestrated neuroimmune response within the muscularis externa (ME) involves activation of resident macrophages, enteric glia and infiltration of blood-derived leukocytes. Interleukin-1 receptor type-I (IL1R1) signalling on enteric glia has been shown to be involved in POI development. Herein we investigated the distinct role of the IL1R1 ligands interleukin (IL) -1α and IL-1β and focused on the mechanism of IL-1β production. IL-1α and IL-1β deficient mice were protected from POI. Bone-marrow transplantation studies indicated that IL-1α originated from radio-resistant cells while IL-1β was released from the radio-sensitive infiltrating leukocytes. Mouse strains deficient in inflammasome formation identified the absent in melanoma 2 (AIM2) inflammasome to be crucial for IL-1β production in POI. Mechanistically, antibiotic-treated mice revealed a prominent role of the microbiome in IL-1β production. Our study provides new insights into distinct roles of IL-1α and IL-1β signalling during POI. While IL-1α release is most likely an immediate passive response to the surgical trauma, IL-1β production depends on AIM2 inflammasome formation and the microbiome. Selective interaction in this pathway might be a promising target to prevent POI in surgical patients.

Postoperative ileus (POI) is a common complication after abdominal surgery characterized by motility disturbances leading to increased morbidity and mortality in surgical patients. Intestinal manipulation of the murine small bowel is an established animal model resulting in an increased postsurgical inflammation within the intestinal muscular externa and a delayed gastrointestinal transit. Some analgesics have been shown to affect inflammation. In this study, we compared the immunomodulatory effects of two different analgesics. Mice were treated with tramadol, metamizole or saline as a control in our established POI model. The postoperative inflammatory response was assessed by gene expression of pro-inflammatory cytokines at different time points and immunocytes extravasation into the muscularis externa. Functional motility analyses were performed by a gastrointestinal transit measurement. Metamizole application reduced the pro-inflammatory response after surgery and improved gastrointestinal motility, while tramadol showed no alteration in cytokine gene expression, influx of immunocytes and gastrointestinal transit compared with the controls. In conclusion. we suggest tramadol as analgesia in immunological studies on POI in mice as it does not affect the underlying inflammation of POI.

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-1β as well as leukocyte infiltration and gastrointestinal transit were analyzed at different time points after IM. IL-6, TNFα, and IL-1β 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.

Purpose Laparoscopic surgery (LS) has proved superior compared to conventional surgery (CS) regarding morbidity, length of hospital stay, rate of wound infection and time until recovery. An improved preservation of the postoperative immune function is assumed to contribute to these benefits though the role of the local peritoneal immune response is still poorly understood. Our study investigates the peritoneal immune response subsequent to abdominal surgery and compares it between laparoscopic and conventional surgery to find an immunological explanation for the clinically proven benefits of LS. Methods Wistar rats (N = 140) underwent laparoscopic cecum resection (LCR; N = 28), conventional cecum resection (CCR; N = 28), laparoscopic sham operation (LSO; N = 28), conventional sham operation (CSO; N = 28), or no surgical treatment (CTRL; N = 28). Postoperatively, peritoneal lavages were performed, leukocytes isolated and analyzed regarding immune function and phagocytosis activity. Results Immune function was inhibited postoperatively in animals undergoing LCR or CCR compared to CTRL reflected by a lower TNF-α (CTRL 3956.65 pg/ml, LCR 2018.48 pg/ml (p = 0.023), CCR 2793.78 pg/ml (n.s.)) and IL-6 secretion (CTRL 625.84 pg/ml, LCR 142.84 pg/ml (p = 0.009), CCR 169.53 pg/ml (p = 0.01)). Phagocytosis was not affected in rats undergoing any kind of surgery compared to CTRL. Neither cytokine secretion nor phagocytosis activity differed significantly between laparoscopic and conventional surgery. Conclusions According to our findings the benefits associated with LS compared to CS cannot be explained by differences in the postoperative peritoneal innate immune response. Further studies are needed to elucidate the causes for a more favorable postoperative outcome in patients after LS compared to CS.

Objective: Postoperative ileus (POI) is an inflammation-mediated complication of abdominal surgery, characterized by intestinal dysmotility and leukocyte infiltration into the muscularis externa (ME). Previous studies indicated that interleukin (IL)-10 is crucial for the resolution of a variety of inflammation-driven diseases. Herein, we investigated how IL-10 affects the postoperative ME inflammation and found an unforeseen role of IL-10 in POI. Design: POI was induced by a standardized intestinal manipulation (IM) in C57BL/6 and multiple transgenic mouse strain including C-C motif chemokine receptor 2-/-, IL-10-/-, and LysMcre/IL-10fl/fl mice. Leukocyte infiltration, gene and protein expression of cytokines, chemokines, and macrophage differentiation markers as well as intestinal motility were analyzed. IL-10 serum levels in surgical patients were determined by ELISA. Results: IL-10 serum levels were increased in patient after abdominal surgery. In mice, a complete or leucocyte-restricted IL-10 deficiency ameliorated POI and reduced the postoperative ME neutrophil infiltration. Infiltrating monocytes were identified as main IL-10 producers and undergo IL-10-dependent M2 polarization. Interestingly, M2 polarization is not crucial to POI development as abrogation of monocyte infiltration did not prevent POI due to a compensation of the IL-10 loss by resident macrophages and neutrophils. Organ culture studies demonstrated that IL-10 deficiency impeded neutrophil migration toward the surgically traumatized ME. This mechanism is mediated by reduction of neutrophil attracting chemokines. Conclusion: Monocyte-derived macrophages are the major IL-10 source during POI. An IL-10 deficiency decreases the postoperative expression of neutrophil-recruiting chemokines, consequently reduces the neutrophil extravasation into the postsurgical bowel wall, and finally protects mice from POI.

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-1β 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-1β 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.

Postoperative peritoneal adhesions are common sequelae of abdominal surgery. Acute as well as chronic complications, including bowel obstruction, abdominal pain and infertility can arise from adhesion formation. So far, the only reliable treatment is surgical adhesiolysis, which in turn is accompanied by an increased risk of adhesion recurrence. Despite significant progress in modern perioperative medicine, only limited prophylactic approaches are available and atraumatic surgery is still the most important factor.Current research concepts focus on two major antiadhesion strategies: firstly, the intraoperative placement of mechanical barriers and secondly novel immunomodulation concepts. Clinical data about the use of antiadhesive barriers show a heterogeneous outcome. Promising data have arisen from the immunomodulatory approaches and now require a step-up development from experimental to clinical trial level.The present review gives a short overview about the current research on the pathophysiology and prevention of peritoneal adhesions. The promising data are encouraging and require realization of carefully designed prospective clinical trials.

Der postoperative Ileus (POI) ist definiert als ein vorubergehender Stillstand der koordinierten Darmperistaltik nach operativen Eingriffen, der eine ausreichende Passage des Darminhalts bzw. die Toleranz der oralen Nahrungsaufnahme verhindert. Dieses haufige Krankheitsbild ist verbunden mit einem Anstieg der perioperativen Morbiditat, einer Verlangerung der Krankenhausverweildauer und einer Erhohung der Kosten. Die Pathogenese des POI ist multifaktoriell: Neben einer Peristaltikhemmung durch inhibitorische neuronale Reflexbogen und der Gabe von Opioiden spielen, insbesondere bei der protrahierten und uber Tage andauernden Form, immunologische Mechanismen eine entscheidende Rolle. Hierbei kommt es durch das chirurgische Trauma zu einer Aktivierung von residenten Makrophagen der Tunica muscularis (ME), was letztlich zu einer Freisetzung von proinflammatorischen Mediatoren und einer Ausbreitung der Entzundung auf den gesamten Gastrointestinaltrakt fuhrt. Bis heute existieren weder eine Prophylaxe noch eine evidenzbasierte Therapie. Da die gangigen Konzepte (z. B. die Gabe von Prokinetika) in randomisierten Studien keinen signifikanten Vorteil erbringen konnten, erscheint nach aktueller Datenlage das fruhe Eingreifen in die immunologischen Prozesse eine erfolgversprechende Option zur Prophylaxe des POI zu sein. Ziel dieses Manuskripts ist es, eine Ubersicht uber die dem POI zugrunde liegenden immunologischen Prozesse zu verfassen und nachfolgend einen Fokus auf aktuelle Therapiemasnahmen und zukunftige potenzielle Optionen der Prophylaxe des POIs zu setzen.

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.

Standardized intestinal manipulation (IM) leads to local bowel wall inflammation subsequently spreading over the entire gastrointestinal tract. Previously, we demonstrated that this so-called gastrointestinal field effect (FE) is immune-mediated. The aim of this study was to investigate the role of secondary lymphoid organs [mesenteric lymph nodes (MLN), gut-associated lymphoid tissue (GALT)] in IM-mediated FE by employing mice with deficient secondary lymphoid organs (aly/aly, MLN ex) or by administration of 2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol (FTY720), an immunomodulating agent that inhibits emigration of lymphocytes out of lymphoid organs. Small bowel muscularis, and colonic muscularis from wild-type mice as control, from aly/aly mice, FTY720-treated mice (daily dose of 1.0 mg/kg mouse ip starting 3 days before surgical procedure), and wild-type mice that had undergone removal of mesenteric lymph nodes before IM (MLN ex mice) were obtained after selective IM of the jejunum or sham operation. FE was analyzed by measuring transit time of orally administered fluorescent dextran in the gastrointestinal tract [geometric center (GC) of fluorescent dextran], colonic transit time, infiltration of myeloperoxidase-positive cells, and circular smooth muscle contractility. Furthermore, mRNA levels of inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1α] were determined by Taqman-PCR. We observed a significantly reduced upregulation of proinflammatory cytokines (IL-6, TNF-α, MIP-1α) in colonic muscularis of MLN ex mice, aly/aly mice, and FTY720-treated mice compared with wild-type mice. Contractility of circular muscularis strips of the colon but not the jejunum was significantly improved in aly/aly mice and FTY720-treated wild-type mice. Additionally, inflammation of the colon determined by the number of myeloperoxidase-positive cells and colonic transit time were significantly improved in aly/aly mice, FTY720-treated wild-type mice, and in MLN ex mice. In summary, lack of secondary lymphoid organs (MLN + GALT) in aly/aly mice or administration of FTY720 abrogated FE after IM as opposed to wild-type mice. These data demonstrate that secondary lymphoid organs are involved in the propagation of FE and postoperative ileus. FTY720 indirectly affects FE by inhibiting migration of activated T cells from the jejunum and adjacent secondary lymphoid organs to the colon. These findings support the crucial role of the adaptive immune system in FE, most likely by a sphyngosine 1-phosphate-dependent mechanism.

Introduction Postoperative ileus (POI) is a frequent complication after abdominal surgery (AS). Until today, neither a prophylaxis nor an evidence-based therapy exists. This originates from the absence of objective parameters evaluating the severity and duration of POI resulting in clinical trials of modest quality. The SmartPill®, a capsule which frequently measures pH value, temperature and intraluminal pressure after swallowing, offers an elegant option for analysing gastrointestinal (GI) transit times and smooth muscle activity in vivo. As the use in patients in the first months after AS is not covered by the marketing authorisation, we aim to investigate the safety and feasibility of the SmartPill® immediately after surgery. Additionally, we analyse the influence of prokinetics and laxatives as well as standardised physiotherapy on postoperative bowel contractility, as scientific evidence of its effects is still lacking. Methods and analysis The PIDuSA study is a prospective, single-centre, two-arm, open-label trial. The SmartPill® will be applied to 55 patients undergoing AS having a high risk for POI and 10 patients undergoing extra-abdominal surgery rarely developing POI. The primary objective is the safety of the SmartPill® in patients after surgery on the basis of adverse device effects/serious adverse device effects (ADE/SADE). The sample size suggests that events with a probability of 3% could be seen with a certainty of 80% for at least once in the sample. Secondary objective is the analysis of postoperative intestinal activity in the GI tract in both groups. Furthermore, clinical signs of bowel motility disorders will be correlated to the data measured by the SmartPill® to evaluate its significance as an objective parameter for assessing POI severity. Additionally, effects of prokinetics, laxatives and physiotherapy on postoperative peristaltic activity recorded by the SmartPill® will be analysed. Ethics and dissemination The protocol was approved by the federal authority (94.1.05-5660-8976) and the local ethics committee (092/14-MPG). Findings will be disseminated through publications and conference presentations. Trial registration number NCT02329912; Pre-results.

In recent years, multimodal treatment approaches have led to an increased median survival time of patients with colorectal liver metastases. In particular, this results from new perioperative chemotherapy regimens, which in turn are accompanied by an increased risk of perioperative bleeding and/or liver failure due to the hepatotoxic side effects. Nineteen to 58 % of patients treated with oxaliplatin develop sinusoidal obstruction syndrome (SOS). The influence of preexisting SOS on liver surgery remains controversial. Animals were operated 4 days after SOS induction with monocrotaline and received either vascular occlusion in the form of Pringle maneuver (PM) or hepatectomy (LR; 70 %) or a combination of both (LR + PM). Postoperative liver function was assessed by determination of liver enzyme levels, bile production, and tissue oxygen saturation. Preexisting SOS impaired morbidity after liver resection, reflected by elevated liver enzyme levels, reduced bile secretion, and low liver tissue oxygenation levels. Mortality was increased by up to 25 %. Additional ischemia in the form of PM showed no further impact in the LR ± PM group compared to LR alone. PM without LR results in high enzyme distribution in the SOS group. SOS significantly affects the outcome after liver resection in our experimental rat model only without PM and showed no protective effect in ischemia in the form of PM.

Clinical evidence suggests that recurrent acute cellular rejection (ACR) may trigger chronic rejection and impair outcome after intestinal transplantation. To test this hypothesis and clarify underlying molecular mechanisms, orthotopic/allogenic intestinal transplantation was performed in rats. ACR was allowed to occur in a MHC-disparate combination (BN-LEW) and two rescue strategies (FK506monotherapy vs. FK506+infliximab) were tested against continuous immunosuppression without ACR, with observation for 7/14 and 21 days after transplantation. Both, FK506 and FK506+infliximab rescue therapy reversed ACR and resulted in improved histology and less cellular infiltration. Proinflammatory cytokines and chemotactic mediators in the muscle layer were significantly reduced in FK506 treated groups. Increased levels of CD4, FOXP3 and IL-17 (mRNA) were observed with infliximab. Contractile function improved significantly after FK506 rescue therapy, with a slight benefit from additional infliximab, but did not reach nontransplanted controls. Fibrosis onset was detected in both rescue groups by Sirius-Red staining with concomitant increase of the fibrogenic mediator VEGF. Recovery from ACR could be attained by both rescue therapy regimens, progressing steadily after initiation of immunosuppression. Reversal of ACR, however, resulted in early stage graft fibrosis. Additional infliximab treatment may enhance physiological recovery of the muscle layer and enteric nervous system independent of inflammatory reactions.

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.

Ischemia-reperfusion injury leads to impaired smooth muscle function and inflammatory reactions after intestinal transplantation. In previous studies, infliximab has been shown to effectively protect allogenic intestinal grafts in the early phase after transplantation with resulting improved contractility. This study was designed to reveal protective effects of infliximab on ischemia-reperfusion injury in isogenic transplantation.Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (3 h cold ischemia). Five groups were defined: non-transplanted animals with no treatment (group 1), isogenic transplanted animals with vehicle treatment (groups 2/3) or with infliximab treatment (5 mg/kg body weight intravenously, directly after reperfusion; groups 4/5). The treated animals were sacrificed after 3 (group 2/4) or 24 h (group 3/5). Histological and immunohistochemical analysis, TUNEL staining, real-time RT-PCR, and contractility measurements in a standard organ bath were used for determination of ischemia-reperfusion injury.All transplanted animals showed reduced smooth muscle function, while no significant advantage of infliximab treatment was observed. Reduced infiltration of neutrophils was noted in the early phase in animals treated with infliximab. The structural integrity of the bowel and infiltration of ED1-positive monocytes and macrophages did not improve with infliximab treatment. At 3 h after reperfusion, mRNA expression of interleukin (IL)-6, TNF-α, IL-10, and iNOS and MCP-1 displayed increased activation in the infliximab group.The protective effects of infliximab in the early phase after experimental small bowel transplantation seem to be unrelated to ischemia-reperfusion injury. The promising effects in allogenic transplantation indicate the need for further experiments with infliximab as complementary treatment under standard immunosuppressive therapy. Further experiments should focus on additional infliximab treatment in the setting of acute rejection.

Localized abdominal surgery can lead to disruption of motility in the entire gastrointestinal tract (postoperative ileus). Intestinal macrophages produce mediators that paralyze myocytes, but it is unclear how the macrophages are activated, especially those in unmanipulated intestinal areas. Here we show that intestinal surgery activates intestinal CD103(+)CD11b(+) dendritic cells (DCs) to produce interleukin-12 (IL-12). This promotes interferon-γ (IFN-γ) secretion by CCR9(+) memory T helper type 1 (T(H)1) cells which activates the macrophages. IL-12 also caused some T(H)1 cells to migrate from surgically manipulated sites through the bloodstream to unmanipulated intestinal areas where they induced ileus. Preventing T cell migration with the drug FTY720 or inhibition of IL-12, T-bet (T(H)1-specific T box transcription factor) or IFN-γ prevented postoperative ileus. CCR9(+) T(H)1 memory cells were detected in the venous blood of subjects 1 h after abdominal surgery. These findings indicate that postoperative ileus is a T(H)1 immune-mediated disease and identify potential targets for disease monitoring and therapy.

Gut manipulation and ischemia/reperfusion evoke an inflammatory response within the intestinal muscularis that contributes to dysmotility. We hypothesize that resident macrophages play a key role in initiating the inflammatory cascade. Isogenic small bowel transplantation was performed in Lewis rats. The impact of recovery of organs on muscularis inflammation was investigated by comparing cold whole-body perfusion after versus prior to recovery. The role of macrophages was investigated by transplantation of macrophage-depleted gut. Leukocytes were counted using muscularis whole mounts. Mediator expression was determined by real-time RT-PCR. Contractility was assessed in a standard organ bath. Both organ recovery and ischemia/reperfusion induced leukocyte recruitment and a significant upregulation in IL-6, MCP-1, ICAM-1 and iNOS mRNAs. Although organ recovery in cold ischemia prevented early gene expression, peak expression was not changed by modification of the recovery technique. Compared to controls, transplanted animals showed a 65% decrease in smooth muscle contractility. In contrast, transplanted macrophage-depleted isografts exhibited significant less leukocyte infiltration and only a 19% decrease in contractile activity. In summary, intestinal manipulation during recovery of organs initiates a functionally relevant inflammatory response within the intestinal muscularis that is massively intensified by the ischemia reperfusion injury. Resident muscularis macrophages participate in initiating this inflammatory response.

Background Laparoscopic Surgery has become a worldwide standard procedure for a variety of indications. This has been attributed to a milder postoperative inflammatory response by the innate immune system potentially mediated through immune mediators released by the visceral adipose tissue (VAT). However, an in vivo experimental evidence is lacking and is the issue of our present study. Methods Male Wistar rats (N = 24) underwent standardized surgical procedures of conventional cecum resection (CCR), conventional sham operation, laparoscopic cecum resection (LCR), or laparoscopic sham operation. Cytokine expression of leptin, resistin, and IL-6 was analyzed in VAT before and after resection by quantitative RT-PCR. Results Postoperative leptin gene expression was reduced in the CCR and LCR groups, while expression was not significantly affected in both sham groups compared to the preoperative levels. In contrast, IL-6 expression was not affected in the LCR group, but was significantly elevated in the CCR cohort. The IL-6 expression was significantly higher in CCR compared to LCR. Resistin expression levels did not differ between all groups. Conclusions Our study underlines the role of immunological involvement of VAT in the postoperative phase. Low leptin levels seem to act as a stimulator for energy uptake in order to cope with postoperative stress. A lower IL-6 expression in the LCR compared to the CCR group may indicate a weaker inflammatory activity potentially adding to the clinical benefits observed in patients undergoing LS.

Aims Postoperative ileus (POI) is a frequent complication after abdominal surgery, resulting from an inflammation of the muscularis externa (ME). So far no valid biomarker for occurrence, duration or intensity of POI exists. Extravasation of monocytes and neutrophils from blood circulating into the postoperative ME is well known as a hallmark of POI. In a previous study we demonstrated that a low abundant subset of T H 1 cells, activated by IL-12, can be detected in the peripheral blood of a small subset of patients in response to abdominal surgery. The aim of the present study was to investigate if these specific T H 1 cells, IL-12 or circulating leukocyte levels could act as a valid marker for POI occurrence. Main methods At different time points, blood samples of patients undergoing abdominal or extraabdominal surgery were collected. Serum levels of IL-12 or T H 1 cells as well as neutrophils and monocytes were analyzed. Data were compared between both groups and correlated with clinical signs of POI. Key findings Time until first flatus and defecation as well as solid food tolerances are delayed after abdominal compared to extraabdominal surgery. Circulating IL-12 levels and numbers of T H 1 cells, neutrophils and monocytes did not differ between both groups. Significance While previous experiments indicated that specific T H 1 cells play a crucial role in POI dissemination, our present data from a larger human cohort demonstrate that they do not seem to be suitable to distinguish between abdominal and extraabdominal surgery. Furthermore neither T H 1 cells nor leukocytes or serum IL-12 levels are appropriate biomarkers for POI in a clinical setting.

Resolution of inflammation is an active counter-regulatory mechanism involving polyunsaturated fatty acid-derived proresolving lipid mediators. Postoperative intestinal motility disturbances, clinically known as postoperative ileus, occur frequently after abdominal surgery and are mediated by a complex inflammation of the intestinal muscularis externa. Herein, we tested the hypothesis that proresolving lipid mediators are involved in the resolution of postoperative ileus. In a standardized experimental model of postoperative ileus, we detected strong expression of 12/15-lipoxygenase within the postoperative muscularis externa of C57BL/6 mice, predominately located within CX3CR1+/Ly6C+ infiltrating monocytes rather than Ly6G+ neutrophils. Mass spectrometry analyses demonstrated that a 12/15-lipoxygenase increase was accompanied by production of docosahexaenoic acid-derived lipid mediators, particularly protectin DX and resolvin D2, and their common precursor 17-hydroxy docosahexaenoic acid. Perioperative administration of protectin DX, but not resolvin D2 diminished blood-derived leukocyte infiltration into the surgically manipulated muscularis externa and improved the gastrointestinal motility. Flow cytometry analyses showed impaired Ly6G+/Ly6C+ neutrophil extravasation after protectin DX treatment, whereas Ly6G-/Ly6C+ monocyte numbers were not affected. 12/15-lipoxygenase-deficient mice, lacking endogenous protectin DX synthesis, demonstrated increased postoperative leukocyte levels. Preoperative intravenous administration of a docosahexaenoic acid-rich lipid emulsion reduced postoperative leukocyte infiltration in wild-type mice but failed in 12/15-lipoxygenase-deficient mice mice. Protectin DX application reduced leukocyte influx and rescued 12/15-lipoxygenase-deficient mice mice from postoperative ileus. In conclusion, our results show that 12/15-lipoxygenase mediates postoperative ileus resolution via production of proresolving docosahexaenoic acid-derived protectin DX. Perioperative, parenteral protectin DX or docosahexaenoic acid supplementation, as well as modulation of the 12/15-lipoxygenase pathway, may be instrumental in prevention of postoperative ileus.

Understanding social context is an important skill for robots that share a space with humans. In this paper, we address the problem of recognizing gender, a key piece of information when interacting with people and understanding human social relations and rules. Unlike previous work which typically considered faces or frontal body views in image data, we address the problem of recognizing gender in RGB-D data from side and back views as well. We present a large, gender-balanced, annotated, multi-perspective RGB-D dataset with full-body views of over a hundred different persons captured with both the Kinect v1 and Kinect v2 sensor. We then learn and compare several classifiers on the Kinect v2 data using a HOG baseline, two state-of-the-art deep-learning methods, and a recent tessellation-based learning approach. Originally developed for person detection in 3D data, the latter is able to learn the best selection, location and scale of a set of simple point cloud features. We show that for gender recognition, it outperforms the other approaches for both standing and walking people while being very efficient to compute with classification rates up to 150 Hz.

Introduction Intestinal manipulation leads to local bowel wall inflammation that subsequently spreads over the entire gastrointestinal tract. Previously, this gastrointestinal field effect had been demonstrated by us in a rodent model. We herein postulated an immunologic mechanism mediated by activated leukocytes. The aim of this study was to investigate the activation, maturation and migration of dendritic cells (DC) of the intestinal smooth muscle following surgical trauma and i.p. lipopolysaccharide challenge. Methods Mice underwent standardized intestinal manipulation or iP LPS administration and tissues (intestinal muscularis, Peyer’s patches, mesenteric lymph nodes, and spleen) were obtained at various times after manipulation. DC were isolated by tissue digestion and separated by CD11c-iMAG. The harvested DC were analyzed by FACS. The activation pattern of DC was analyzed by polymerase chain reaction. Results We found a significant increase in DC within the intestinal muscularis, the Peyer’s patches and the mesenteric lymph nodes at 6 and 12 hours following intestinal manipulation and injection of LPS. There was an upregulation of the costimulatory molecules major histocompatibility complex II, CD40, CD80, CD86, and CD205 in the DC after intestinal manipulation. CCR-2, CCR-5, CCR-7, CCL-19, and interleukin-12a were upregulated in a time- and tissue-dependent manner. Conclusion Intestinal manipulation or LPS challenge induced a recruitment of DC into the muscularis externa and mesenteric lymph nodes combined with an upregulation of costimulatory immunocompetent molecules and migratory surface markers in DCs. These findings demonstrate a precondition for an immunologic response and a possible immunologically mediated gastrointestinal field effect.

BACKGROUND Resident macrophages within the tunica muscularis are known to play a crucial role in initiating severe inflammation in response to ischemia reperfusion injury after intestinal transplantation contributing to graft dysmotility, bacterial translocation, and possibly, acute rejection. The p38 mitogen-activated protein kinase is a key player in the signaling of proinflammatory cytokine synthesis in macrophages. Therefore, we investigated the effects of CPSI-2364, an apparent macrophage-specific inhibitor of the p38 mitogen-activated protein kinase pathway in an isogenic intestinal rat transplantation model. METHODS Recipient and donor animals were treated perioperatively with CPSI-2364 (1 mg/kg, intravenously) or vehicle solution. Nontransplanted animals served as control. Animals were killed 30 min, 3 hr, and 18 hr after reperfusion. RESULTS CPSI-2364 treatment resulted in significantly less leukocyte infiltration and significantly improved graft motor function (18 hr). Messenger RNA expression of proinflammatory cytokines (interleukin 6) and kinetic active mediators (NO) was reduced by CPSI-2364 in the early phase after transplantation. Histologic evaluation revealed the protective effects of CPSI-2364 treatment by a significantly less destruction of mucosal integrity at all time points. Perioperative treatment with CPSI-2364 improves graft motor function through impaired inflammatory responses to ischemia reperfusion injury by inhibition of proinflammatory cytokines and suppression of nitric oxide production in macrophages. CONCLUSIONS CPSI-2364 presents as a promising complementary pharmacological approach preventing postoperative dysmotility for clinical intestinal transplantation.

Postoperative ileus (POI) is an iatrogenic complication of abdominal surgery, mediated by a severe inflammation of the muscularis externa (ME). Previously, we demonstrated that intravenous application of the tetravalent guanylhydrazone semapimod (CNI-1493) prevents POI, but the underlying mode of action could not definitively be confirmed. Herein, we investigated the effect of a novel orally active salt of semapimod (CPSI-2364) on POI in rodents and distinguished between its inhibitory peripheral and stimulatory central nervous effects on anti-inflammatory vagus nerve signaling. Distribution of radiolabeled orally administered CPSI-2364 was analyzed by whole body autoradiography and liquid scintillation counting. POI was induced by intestinal manipulation with or without preoperative vagotomy. CPSI-2364 was administered preoperatively via gavage in a dose- and time-dependent manner. ME specimens were assessed for p38-MAP kinase activity by immunoblotting, neutrophil extravasation, and nitric oxide production. Furthermore, in vivo gastrointestinal (GIT) and colonic transit were measured. Autoradiography demonstrated a near-exclusive detection of CPSI-2364 within the gastrointestinal wall and contents. Preoperative CPSI-2364 application significantly reduced postoperative neutrophil counts, nitric oxide release, GIT deceleration, and delay of colonic transit time, while intraoperatively administered CPSI-2364 failed to improve POI. CPSI-2364 also prevents postoperative neutrophil increase and GIT deceleration in vagotomized mice. Orally administered CPSI-2364 shows a near-exclusive dispersal in the gastrointestinal tract and effectively reduces POI independently of central vagus nerve stimulation. Its efficacy after single oral dosage affirms CPSI-2364 treatment as a promising strategy for prophylaxis of POI.

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).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.The present manuscript will give an update on the inflammatory responses, the involved cell types, and participating immune mediators in POI.

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. 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. 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

Significant improvements of graft and patient survival have been achieved over the past 20 years in the field of intestinal transplantation. Tacrolimus monotherapy with corticosteroids, or in combination with sirolimus is the most commonly used immunosuppressive regimen. Early (24h) after experimental allogenic small bowel transplantation in rats, sirolimus reduces the cellular and molecular inflammatory response with subsequent graft dysmotility more efficiently than tacrolimus, with contrary effects at 7 days after transplantation. This study evaluates three immunosuppressive strategies in the post-acute phase after intestinal transplantation - tacrolimus or sirolimus monotherapy and the combination therapy of tacrolimus with infliximab. After orthotopic intestinal transplantation between Brown Norway and Lewis rats, animals received 14 days of immunosuppressive treatment. Histology, infiltration of neutrophils, monocytes and macrophages, cytokine and mediator mRNA expression (real time RT-PCR) and smooth muscle function in a standard organ bath were assessed at 14 days after transplantation in all treatment groups and isogenic controls. Allogenic transplanted rats without immunosuppressive therapy and non-transplanted animals served as further control. Tacrolimus prevented acute rejection and graft dysmotility more effectively (p ≥ 0.05) than sirolimus. Reduced mRNA expression levels of CD4, IFN-γ, IL-6, IL-10, iNOS, NFκB, TNF-α and MCP-1 (p ≤ 0.05) were observed in tacrolimus treated animals compared to sirolimus. Additional infliximab application did not influence the cellular and molecular inflammatory response in the post-acute phase after transplantation. In conclusion, the severe cellular and molecular inflammatory response in allogenic transplanted grafts without immunosuppressive therapy is ameliorated by all three immunosuppressive regimens, but tacrolimus was found to be more efficient than sirolimus at 14 days after transplantation. Our findings do not rule out the usage of sirolimus as single immunosuppressive therapy, but indicate and confirm the potency and effectivity of tacrolimus as basis immunosuppressant in the field of intestinal transplantation.

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. 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. 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. 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.

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).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.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.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.

Background. The mechanical trauma of the gut is an unavoidable consequence of abdominal surgery leading to postoperative ileus (POI). Former studies revealed that activation of resident macrophages in the muscularis externa (ME) is an initial step in the inflammatory cascade resulting in massive inflammation of the bowel wall with intestinal dysmotility [1, 2]. The aim of this study was to investigate the efficacy of the macrophage-specific c-Raf-pathway inhibitor CPSI 2364 in preventing POI in swine. Additionally, we investigated disturbances of intestinal wound repair, as macrophage-function is essential in this process [3]. Materials and Methods. Swine were treated orally with placebo or 1mg/kg CPSI 2364 before standardized intestinal manipulation. 24 h later swine were sacrificed and the whole digestive tract was removed for further investigation. Inflammation within the ME of the small bowel was quantified using RT-PCR (MCP-1) and a myeloperoxidase-assay. To examine smooth muscle function, jejunal muscularis strips were exposed to an increasing concentration of a muscarinic agonist in an in vitro organ bath and contractility was analyzed. Furthermore intestinal transit time was measured in vivo. In a second experiment swine received an anastomosis of the colon to examine intestinal wound repair. On postoperative day 6 mRNA levels of wound healing parameters (VEGF, Collagen 1 and 3) and perianastomotic hydroxyproline concentration were examined. To assess mechanical strength bursting pressure was measured. Results. After treatment with CPSI 2364 a significant inflammatory reduction within the ME on mRNA- and cell-level could be demonstrated. Furthermore, smooth muscle function was improved, resulting in an accelerated intestinal transit time and an elevated contractility. Clinical course and perianastomotic mRNA-levels, hydroxyproline concentration or bursting pressure showed no evidence of impaired intestinal wound healing. Conclusion. Preoperative application of CPSI 2364 reduces postoperative inflammation within the ME subsequently preventing POI. A detrimental influence of CPSI 2364 on intestinal wound repair could not be demonstrated.

Introduction: Abdominal surgery results in the inflammation of the tunica muscularis (ME), subsequently leading to postoperative ileus (POI) [1]. Previously, we demonstrated that inhibition of macrophage function and cytokine production prevents rodents from POI [2]. Omega-3 and omega-6 polyunsaturated fatty acids (PUFA) are known to exert anti- or proinflammatory effects, respectively. The aim of this study was to analyze the effect of omega-3 and omega-6 PUFA on POI in rodents. Methods: Male rats and mice underwent intestinal manipulation (IM) after 5 days preoperative enteral or parenteral application of vehicle, omega-3 (Omegaven®) or omega-6 (Lipovenos®-MCT) PUFA-enriched emulsions (1 ml/100 g bodyweight, once daily). Erythrocyte membranes were analyzed by gas chromatography for fatty acid composition. Inflammatory activity was determined by detection of neutrophils 24 h after IM. Production of nitric oxide (NO) from ME specimen was determined by Griess reaction. Contractility of jejunal ME strips was measured in vitro in an organ bath setup. Gastrointestinal and colonic transits were determined in vivo. Results: Omegaven treatment significantly increased omega-3 to omega-6 PUFA rates in erythrocytes (1 : 9), compared to untreated controls (1 : 15). Furthermore, Omegaven reduced neutrophil levels (–35 %) and NO production (–38 %) after IM and improved contractility and gastrointestinal and colonic transit time. Interestingly, enteral Omegaven treatment showed increased NO production and tended toward increased neutrophils levels. In all experiments, Lipovenos-MCT treatment solely showed a trend to reduced inflammation and improved motility. Conclusion: Perioperative parenteral omega-3 PUFA enriched nutrition reduces intestinal inflammation and prevents postoperative ileus.

Background Postoperative ileus is mediated through a severe inflammation of the tunica muscularis. Inhibition of initially involved muscularis macrophages could be a promising clinical approach to prevent postoperative ileus. The aim of this study was to investigate whether pharmacologic or genetic depletion of these inflammatory cells influences anastomotic healing. Methods Standardized ileal anastomoses were performed and the mice were randomized into 4 groups: (1) wild type; (2) pharmacologically depleted and inactivated, by means of chlodronate liposomes and gadolinium chloride; (3) heterozygous osteopetrosis littermates; (4) genetically depleted osteopetrosis mutant mice. Tissues from the anastomoses were removed 2, 5, and 14 days after surgery and used for molecular (collagen 1 and 3, matrix metalloproteinases 2, 9, and 13 expressions), histochemical (anastomotic healing score, cross polarization microscopy) and functional (anastomotic bursting pressure) investigations. Results RT-PCR measurements demonstrated that the investigated genetic events were similar between controls and macrophage-depleted groups. Comparison of histologic healing scores and bursting pressure values showed no significant differences between the groups. Finally, cross polarization microscopy on picrosirius-red stained sections revealed no obvious disturbance in production and deposition of collagen. Conclusion In our current model we demonstrate that transient perioperative pharmacologic and genetic muscularis macrophage inhibition does not affect intestinal anastomotic healing. These results call for further investigations to establish a pharmacologic prophylaxis for the prevention of postoperative ileus.

Background The mechanical trauma of the gut is an unavoidable consequence of abdominal surgery leading to massive inflammation of the entire bowel wall and subsequently in postoperative ileus [1]. Further studies revealed the activation of the resident macrophages in the tunica muscularis as an initial step in the inflammatory cascade [2]. The aim of this study was to investigate the effectivity of the macrophage-specific c-Raf-Kinase Inhibitor CPSI 2364 in preventing postoperative ileus in rodents and swine.