Systemic inflammation with enhanced brain activation contributes to more severe delay in postoperative ileus

Postoperative paralytic ileus following debulking surgery in ovarian cancer patients

Aim

This study aims to evaluate the incidence of postoperative ileus (POI) following cytoreductive surgery in epithelial ovarian cancer (EOC) patients and its impact on anastomotic leakage occurrence and postoperative complications.

Methods

A total of 357 surgeries were performed on 346 ovarian cancer patients between 1/2010 and 12/2020 at our institution. The postoperative course regarding paralytic ileus, anastomotic leakage, and postoperative complications was analyzed by Fisher's exact test and through ordinal logistic regression.

Results

A total of 233 patients (65.3%) returned to normal gastrointestinal functions within 3 days after surgery. A total of 123 patients (34.5%) developed POI. There were 199 anastomoses in 165 patients and 24 leakages (12.1%). Postoperative antibiotics (p 0.001), stoma creation (p 0.0001), and early start of laxatives (p 0.0048) significantly decreased POI, while anastomoses in general (p 0.0465) and especially low anastomoses (p 0.0143) showed increased POI rates. Intraoperative positive fluid excess >5,000 cc was associated with a higher risk for POI (p 0.0063), anastomotic leakage (p 0.0254), and severe complications (p 0.0012).

Conclusion

Postoperative antibiotics, an early start with laxatives, and stoma creation were associated with reduced POI rates. Patients with anastomoses showed an increased risk for POI. Severe complications, anastomotic leakages, and POI were more common in the case of intraoperative fluid balance exceeding 5,000 cc.

Effect of multimodal preemptive analgesia on postoperative gastrointestinal function and clinical outcome in patients undergoing laparoscopic colorectal surgery

OBJECTIVE

This study aimed to investigate the effects of multimodal preemptive analgesia on postoperative gastrointestinal function and clinical outcomes in patients undergoing laparoscopic colorectal surgery.

METHODS

This prospective study included a total of 108 patients undergoing elective laparoscopic colorectal surgery from June 2019 to June 2020. The patients were divided into the control group and the study group according to the random number table method. Patients in the study group were given flurbiprofen axetil and oxycodone before skin incision combined with bilateral transverse abdominis plane block (TAPB) before anaesthesia induction. In the control group, patients were given sufentanil and flurbiprofen axetil combined with bilateral TAPB in postanaesthesia care unit (PACU). The incidence of postoperative gastrointestinal dysfunction (POGD), I-FEED score, inflammatory factor levels, rehabilitation indicators, postoperative pain assessment and other organ complications were observed and compared between the two groups.

RESULTS

The incidence of POGD in the study group was lower compared to the control group, and the difference was statistically significant (P < .05). The study group had lower total and mean scores of I-FEED at 24, 48, 72 and 96 hours after surgery; however, the differences were not statistically significant (P > .05). On the first and third day after operation, Lipopolysaccharide (LPS), C-reactive protein (CRP), Tumour necrosis factor (TNF-α) and Interleukins6 (IL-6) levels of the study group decreased significantly (P < .05). The reduction in inflammation factor levels from 1d to 3d was significantly greater than that of the control group (P < .05).

CONCLUSION

The strategy of multimodal preemptive analgesia can effectively prevent the onset of POGD and may accelerate rehabilitation. In short, multimodal preemptive analgesia provides a novel prevention strategy for patients undergoing laparoscopic colorectal surgery.

Post-operative ileus: definitions, mechanisms and controversies

Post-operative ileus (POI) is a syndrome of impaired gastrointestinal transit which occurs following abdominal surgery. There are few effective targeted therapies for ileus, and research has been limited by inconsistent definitions and an incomplete understanding of the underlying pathophysiology. Despite considerable effort, there remains no widely-adopted definition of ileus, and recent work has identified variation in outcome reporting is a major source of heterogeneity in clinical trials. Outcomes should be clearly-defined, clinically-relevant, and reflective of the underlying biology, impacts on hospital resources and quality of life. Further collaborative efforts will be needed to develop consensus definitions and a core outcome set for postoperative gastrointestinal recovery. Investigation into the pathophysiology of POI has been hindered by use of low-resolution techniques and difficulties linking cellular mechanisms to dysmotility patterns and clinical symptoms. Recent evidence has suggested the common assumption of post-operative GI paralysis is incorrect, and that the distal colon becomes hyperactive following surgery. The post-operative inflammatory response is important in the pathophysiology of ileus, but the time course of this in humans remains unclear, with the majority of evidence coming from animal models. Future work should investigate dysmotility patterns underlying ileus, and identify biomarkers which may be used to diagnose, monitor and stratify patients with ileus.

Effects of a high body mass index on the short-term outcomes and prognosis after radical gastrectomy

PURPOSE

This study aimed to investigate the effects of a high body mass index (BMI) on the outcomes of radical gastrectomy for gastric cancer.

METHODS

We conducted a retrospective cohort study of 1729 patients with stage I to III gastric cancer who received open radical gastrectomy from February 2003 to August 2011. The patients were divided into 3 groups according to their BMI: a low BMI group (BMI < 18.5 kg/m²), normal BMI group (18.5 ≤ BMI < 25 kg/m²), and high BMI group (BMI ≥ 25 kg/m²).

RESULTS

A total of 871 patients were included in the final analysis, of which the median BMI was 22.7 kg/m² (range 13.6-44.9 kg/m²). A high BMI increased the risk of postoperative intestinal fistula but not the risk of a reduced number of examined lymph nodes or hospital death. Furthermore, a high BMI did not negatively affect the overall survival (OS) of gastric cancer patients.

CONCLUSIONS

A high BMI increased the operative morbidity after radical gastrectomy for gastric cancer. However, a high BMI did not negatively affect the quality of lymphadenectomy or the OS of gastric cancer patients in experienced high-volume centers. A careful approach during operation and meticulous perioperative management are required for gastric cancer patients with a high BMI.

Traditional Chinese Medicine Da-Cheng-Qi-Tang Ameliorates Impaired Gastrointestinal Motility and Intestinal Inflammatory Response in a Mouse Model of Postoperative Ileus

This study was to explore the therapeutic effect and mechanism of the traditional Chinese medicine with the formula Da-Cheng-Qi-Tang (T-DCQT) and a modified Da-Cheng-Qi-Tang (M-DCQT) in a postoperative ileus (POI) mouse model. POI was induced via small bowel manipulation, and T-DCQT or M-DCQT was given by enema. The intestinal motility was measured with a charcoal mixture gavage. The intestinal tissues were collected for further studies by histopathological, qPCR, immunohistochemical staining, and Western blotting. Levels of inflammatory cytokines in blood were determined using a high-throughput liquid chip. We found that gastrointestinal dysfunction was alleviated after administration of either a T-DCQT or M-DCQT enema. Increased expression of NF-κB, p38 MAPK, and TLR4 in the intestinal tissues of POI mice were reversed following treatment. IL-1α, IL-6, MIP-1β, and IL-17 levels were significantly reduced at 24 h and 48 h following treatment, while the MCP-1 level was only observed to be reduced at 24 h after the treatment. Furthermore, compared with the T-DCQT effect, M-DCQT treatment was more effective in alleviating the increased IL-6, MIP-1β, and IL-1α levels. So, we draw a conclusion that T-DCQT or M-DCOT could ameliorate the POI-associated inflammatory response and improve GI motility in a POI mouse model.

The clinical and economical impact of postoperative ileus in patients undergoing colorectal surgery

BACKGROUND

Colorectal surgery is associated with postoperative ileus (POI). Despite its widespread manifestation, the influence of POI on recovery, quality of life (QoL), and costs is largely unknown. The aim of this study was to assess whether the inflammatory processes found in experimental studies are also evident in patients undergoing colorectal surgery. In addition, the impact of POI on short and long-term QoL and costs was investigated.

METHODS

We analyzed the outcomes of the SANICS-II trial, including prospective evaluation of inflammatory parameters in blood samples, costs from a societal perspective and QoL, using validated questionnaires. Outcomes were compared between patients with and without POI, and in particular patients with POI as unique complication.

KEY RESULTS

A total of 265 patients (POI, n = 66 vs non-POI, n = 199) were included and 38/66 had POI as only complication. CRP levels were significantly increased on postoperative day (POD) 1, 2, 3, and 4 in patients with POI. Furthermore, plasma levels of cytokines IL-6, Il-8 and IL-10 were significantly increased the first 2 days after resection. Patients with POI had a higher overall complication rate and a reduced QoL 3 months postoperatively, even in the only POI group. Moreover, mean societal cost per patient with POI was 38%-47% higher at 3 months postoperatively.

CONCLUSIONS & INFERENCES

Supporting findings from experimental studies, inflammatory parameters were increased in patients with only POI and comparable with all patients with POI. These results demonstrate the impact and large contribution of POI in postoperative inflammation, costs and QoL in patients undergoing colorectal surgery.

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-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.

Intestinal macrophages and their interaction with the enteric nervous system in health and inflammatory bowel disease

Over the past decades, there has been an increasing understanding of cellular and molecular mechanisms that mediate modulation of the immune system by the autonomic nervous system. The discovery that vagal nerve stimulation (VNS) attenuates endotoxin-induced experimental sepsis paved the way for further studies investigating neuro-immune interaction. In particular, great attention is now given to intestinal macrophages: several studies report the existence of both intrinsic and extrinsic neural mechanisms by which intestinal immune homoeostasis can be regulated in different layers of the intestine, mainly by affecting macrophage activation through neurotransmitter release. Given the important role of inflammation in numerous disease processes, such as inflammatory bowel disease (IBD), cholinergic anti-inflammatory mechanisms are under intense investigation both from a basic and clinical science perspective in immune-mediated diseases such as IBD. This review discusses recent insights on the cross-talk between enteric neurons and the immune system, especially focusing on macrophages, and provides an overview of basic and translational aspects of the cholinergic anti-inflammatory response as therapeutic alternative to reinstall immune homoeostasis in intestinal chronic inflammation.

Alterations in the gut barrier and involvement of Toll-like receptor 4 in murine postoperative ileus

BACKGROUND

The changes in the gut barrier (GB) and associated mechanisms in postoperative ileus (POI) are still unclear. Toll-like receptor 4 (TLR4) is involved in inflammation, which may cause GB dysfunction and POI. Here, the roles of the GB in POI in relation to TLR4-dependent signaling pathways were explored.

METHODS

POI was induced by small bowel manipulation in wild-type (WT) and TLR4-knockout (TLR4-/-) mice. Twenty-four hours after manipulation, indices of gastrointestinal (GI) transit, GB structure and function, inflammation, and related signaling pathways were analyzed.

KEY RESULTS

Normal GI motility and GB function were not affected by TLR4 knockout. Compared with WT POI mice, TLR4-/-POI mice showed milder GI transit retardation, GB dysfunction, and inflammatory responses. In WT mice, GB disorder was characterized by colonic goblet cells depletion, increased gut claudin-2 expression, and decreased CD4+/CD8+ ratios in intestinal Peyer's patches. Green fluorescent protein-tagged Escherichia coli in the gut was detected in plasma and extraintestinal organs, followed with increased plasma lipopolysaccharide. These changes displayed in WT POI mice were less severe in TLR4-/-POI mice. Furthermore, the mRNA and protein expression of interleukin-6, monocyte chemotactic protein-1, pp38 and pJNK in the intestine, and TNF-α level in plasma were significantly increased in WT, but not TLR4-/-POI mice.

CONCLUSIONS & INFERENCES

These results indicate that GB is impaired in the experimental POI, with inflammation being involved in this pathological process. TLR4 deficiency alleviated GB dysfunction and suppressed inflammation by disrupting the activation of mitogen-activated protein kinase signaling pathways, thereby ameliorating POI.

Postoperative ileus following major colorectal surgery

BACKGROUND

Postoperative ileus (POI) is characterized by delayed gastrointestinal recovery following surgery. Current knowledge of pathophysiology, clinical interventions and methodological challenges was reviewed to inform modern practice and future research.

METHODS

A systematic search of MEDLINE and Embase databases was performed using search terms related to ileus and colorectal surgery. All RCTs involving an intervention to prevent or reduce POI published between 1990 and 2016 were identified. Grey literature, non-full-text manuscripts, and reanalyses of previous RCTs were excluded. Eligible articles were assessed using the Cochrane tool for assessing risk of bias.

RESULTS

Of 5614 studies screened, 86 eligible articles describing 88 RCTs were identified. Current knowledge of pathophysiology acknowledges neurogenic, inflammatory and pharmacological mechanisms, but much of the evidence arises from animal studies. The most common interventions tested were chewing gum (11 trials) and early enteral feeding (11), which are safe but of unclear benefit for actively reducing POI. Others, including thoracic epidural analgesia (8), systemic lidocaine (8) and peripheral μ antagonists (5), show benefit but require further investigation for safety and cost-effectiveness.

CONCLUSION

POI is a common condition with no established definition, aetiology or treatment. According to current literature, minimally invasive surgery, protocol-driven recovery (including early feeding and opioid avoidance strategies) and measures to avoid major inflammatory events (such as anastomotic leak) offer the best chances of reducing POI.

Impact of visceral fat on surgical complications and long-term survival of patients with gastric cancer after radical gastrectomy

BACKGROUND/OBJECTIVES

The aim of this study was to examine the impact of visceral fat on surgical complications and long-term survival for patients undergoing radical gastrectomy.

SUBJECTS/METHODS

From 2009 to 2013, 859 patients who underwent curative resection for gastric cancer were enrolled from a prospectively maintained database. Visceral fat area (VFA) was assessed by preoperative CT scans. Patients were divided into two groups by VFA. Perioperative variables and postoperative outcomes were compared between the high VFA group and low VFA group. Univariable and multivariable analysis were performed to investigate independent risk factors of postoperative complications and survival.

RESULTS

Some 859 patients were included in the study, 308 of whom were classified as high VFA. High VFA was correlated with advance age (P = 0.020), higher albumin levels (P = 0.001), hemoglobin levels (P < 0.05), ASA grade (P = 0.043) and Charlson Comorbidity Index (P = 0.004). Relative to patients with low VFA, those with high VFA had longer surgical durations (P = 0.004), higher rate of postoperative complications (P = 0.004), and longer hospital stays (P = 0.004). High VFA was identified as the only determinant for surgical complications by logistic regression analysis (OR, 2.236, 95% CI, 1.537-3.254; P < 0.001). Cox proportional hazards regression revealed no correlation between VFA and overall survival (OS) or disease-free survival (DFS).

CONCLUSIONS

Increased VFA independently predicts surgical complications in patients after gastrectomy. However, VFA is not a prognostic biomarker of OS or DFS in patients with gastric cancer.

Postoperative Ileus: Pathophysiology, Current Therapeutic Approaches

Postoperative ileus, which develops after each abdominal surgical procedure, is an iatrogenic disorder characterized by a transient inhibition of gastrointestinal motility. Its pathophysiology is complex involving pharmacological (opioids, anesthetics), neural, and immune-mediated mechanisms. The early neural phase, triggered by activation of afferent nerves during the surgical procedure, is short lasting compared to the later inflammatory phase. The latter starts after 3-6 h and lasts several days, making it a more interesting target for treatment. Insight into the triggers and immune cells involved is of great importance for the development of new therapeutic strategies. In this chapter, the pathogenesis and the current therapeutic approaches to treat postoperative ileus are discussed.

Relation between postoperative ileus and anastomotic leakage after colorectal resection: a post hoc analysis of a prospective randomized controlled trial

AIM

Anastomotic leakage (AL) following abdominal surgery is a critical determinant of postoperative recovery, of which the aetiology is largely unknown. Interestingly, interventions aimed at reducing the inflammatory response and postoperative ileus (POI) have an unexpected effect on AL. The aim of this study was to investigate the relation of POI with inflammation and AL after colorectal resection.

METHOD

A post hoc analysis of a prospective randomized controlled trial in which patients underwent a colorectal resection was performed. Patients undergoing a colorectal resection were stratified into having or not having POI. The incidence of AL and other clinical parameters was registered prospectively. Intestinal fatty acid binding protein (I-FABP, a marker for tissue damage) and the inflammatory response in plasma and colon tissue were determined.

RESULTS

AL was present in nine of 43 patients in the POI group, and in one of 65 in the group without POI (P < 0.001). There was a significant association between POI and AL (OR 12.57, 95% CI: 2.73-120.65; P = 0.0005). Patients with POI had significantly higher plasma levels of soluble tumour necrosis factor receptor 1 (TNFRSF1A) at 4 h postoperatively (0.89 ng/l, interquartile range 0.56) than patients without POI (0.80 ng/l, interquartile range 0.37; P = 0.04) and higher plasma levels of C-reactive protein on the second day postoperatively (234 ± 77 vs 163 ± 86 mg/l; P = 0.001). Patients who developed AL had significantly higher plasma levels of I-FABP compared with patients without AL at 24 h after onset of surgery.

CONCLUSION

POI is associated with a higher prevalence of AL and an increased inflammatory response.

Electroacupuncture for the prevention of postoperative gastrointestinal dysfunction in participants undergoing vascular laparotomy under general anesthesia: a randomized controlled trial

Background

Postoperative gastrointestinal dysfunction (PGD) is a common complication following laparotomy under general anesthesia (GA). Abdominal distension occurs in 8–28% of surgeries within 24 h postoperatively. The present study aimed to analyze the efficacy of electroacupuncture (EA) for the prevention of PGD by applying preoperative EA stimulation of PC6 (Neiguan), ST36 (Zusanli), and ST37 (Shangjuxv) bilaterally twice within 24 h prior to surgery, compared with no acupuncture treatment.

Methods

The study participants were assessed and selected from participants undergoing vascular laparotomy under GA at the Liver and Vascular Surgery Unit in West China Hospital of Sichuan University. The selected participants were randomly allocated to two groups: routine-treatment (RT) and EA group receiving EA at PC6, ST36, and ST37. A computer-generated list of random numbers was used to determine the allocation of the participants, with numbered opaque sealed envelopes containing the randomization schedule. Eligible participants were all adults aged 18 years or above who were scheduled to undergo vascular laparotomy under GA within 24 h and had no history of EA treatment. The exclusion criteria included participants with serious systemic disease and history of EA treatment. While the RT group received standard treatments, the EA group received additional EA treatments. During each treatment session, EA stimulation was performed for a duration of 20 min at a frequency of 15 Hz with a continuous wave. All such participants received two EA treatments within 24 h before surgery. The outcomes were measured in three metrics: incidence and degree of abdominal distension; first times of flatus and defecation; and duration of hospitalization.

Results

Forty-three participants were recruited, of whom 42 participants successfully completed the study. Each group contained 21 participants. The incidence of abdominal distension (42.8, 76.2%) and degree of abdominal distension were significantly reduced in the EA group (P = 0.03 and P = 0.03, respectively). In comparisons of the first times of flatus (3.05 ± 0.58, 3.29 ± 0.42 days) and defecation (2.81 ± 0.51, 3.20 ± 0.55 days) and duration of hospitalization (5.33 ± 0.68, 5.75 ± 0.66 days), the EA group was superior to the RT group to some extent (P = 0.13, P = 0.02, and P = 0.04, respectively).

Conclusions

Preoperative EA at PC6, ST36, and ST37 might be useful for preventing PGD, thereby improving gastrointestinal function recovery.

Trial registration This study is registered with the Chinese Clinical Trial Registry: ChiCTR-TRC-13003649

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-016-0122-9) contains supplementary material, which is available to authorized users.

Electroacupuncture treatment partly promotes the recovery time of postoperative ileus by activating the vagus nerve but not regulating local inflammation

Postoperative ileus (POI) after abdominal surgery significantly lowers the life quality of patients and increase hospital costs. However, few treatment strategies have successfully shortened the duration of POI. Electroacupuncture (EA) is a modern way of administering acupuncture and widely used in various gastrointestinal (GI) diseases in the world. Here, we studied the effect of EA on POI and its underlying mechanisms. Intestinal manipulation resulted in significant delays of GI transit, colonic transit and gastric emptying. Surgery also up-regulated c-fos in nucleus of the solitary tract (NTS) and induced inflammation response in the small intestine. Further, operation and inhale anesthesia inhibited NTS neuron excitation duration for the whole observation time. EA administered at ST36 indeed shortened the recovery time of GI and colonic transit, and significantly increased the gastric emptying. EA also significantly activated the NTS neurons after operation. However, there was no anti-inflammation effect of EA during the whole experiment. Finally, atropine blocked the regulatory effect of EA on GI function, when it was injected after surgery, but not before surgery. Thus, the regulatory effect of EA on POI was mainly mediated by exciting NTS neurons to improve the GI tract transit function but not by activating cholinergic anti-inflammatory pathway.

The digestive tract as the origin of systemic inflammation

Failure of gut homeostasis is an important factor in the pathogenesis and progression of systemic inflammation, which can culminate in multiple organ failure and fatality. Pathogenic events in critically ill patients include mesenteric hypoperfusion, dysregulation of gut motility, and failure of the gut barrier with resultant translocation of luminal substrates. This is followed by the exacerbation of local and systemic immune responses. All these events can contribute to pathogenic crosstalk between the gut, circulating cells, and other organs like the liver, pancreas, and lungs. Here we review recent insights into the identity of the cellular and biochemical players from the gut that have key roles in the pathogenic turn of events in these organ systems that derange the systemic inflammatory homeostasis. In particular, we discuss the dangers from within the gastrointestinal tract, including metabolic products from the liver (bile acids), digestive enzymes produced by the pancreas, and inflammatory components of the mesenteric lymph.

A Double-Blinded Randomized Clinical Study on the Therapeutic Effect of Gastrografin in Prolonged Postoperative Ileus After Elective Colorectal Surgery

BACKGROUND

Postoperative ileus is a common problem with significant clinical and economic consequences. We hypothesized that Gastrografin may have therapeutic utility by accelerating the recovery of postoperative ileus after colorectal surgery. The aim of this trial was to study the impact of oral Gastrografin administration on postoperative prolonged ileus (PPI) after elective colorectal surgery.

METHODS

The main endpoint of this randomized, double-blinded, controlled trial was time of resolution of PPI. The secondary endpoints were overall hospital length of stay, time to start oral intake, time to first passage of flatus or stools, time of need of nasogastric tube, and need of parenteral nutrition. Included criteria were patients older than 18 years, operated for colonic neoplasia, inflammatory bowel disease, or diverticular disease. There were two treatments: Gastrografin administration and placebo. The sample size was calculated taking into account the average length of postoperative ileus after colorectal resection until tolerance to oral intake. Statistical analysis showed that 29 subjects in each group were needed.

RESULTS

Twenty-nine patients per group were randomized. Groups were comparable for age, gender, ASA Physical Status Classification System, stoma construction, and surgical technique. No statistical differences were observed in mean time to resolution between the two groups, 9.1 days (CI 95%, 6.51-11.68) in Gastrografin group versus 10.3 days (CI 6.96-10.29) in Placebo group (P = 0.878). Even if not statistically significant, time of resolution of PPI, overall length of stay, time of need of nasogastric tube, and time to tolerance of oral intake were shorter in the G group.

CONCLUSIONS

Gastrografin does not accelerate significantly the recovery of prolonged postoperative ileus after elective colorectal resection when compared with placebo. However, it seems to clinically improve all the analyzed variables.

Smooth muscle and neural dysfunction contribute to different phases of murine postoperative ileus

BACKGROUND

Postoperative ileus (POI) is characterized by a transient inhibition of gastrointestinal (GI) motility after abdominal surgery mediated by the inflammation of the muscularis externa (ME). The aim of this study was to identify alterations in the enteric nervous system that may contribute to the pathogenesis of POI.

METHODS

Gastrointestinal transit, contractility of isolated smooth muscle strips and inflammatory parameters were evaluated at different time points (1.5 h to 10 days) after intestinal manipulation (IM) in mice. Immune-labeling was used to visualize changes in myenteric neurons.

KEY RESULTS

Intestinal manipulation resulted in an immediate inhibition of GI transit recovering between 24 h and 5 days. In vitro contractility to K(+) (60 mM) or carbachol (10(-9) to 10(-4) M) was biphasically suppressed over 24 h after IM (with transient recovery at 6 h). The first phase of impaired myogenic contractility was associated with increased expression of TNF-α, IL-6 and IL-1α. After 24 h, we identified a significant reduction in electrical field stimulation-evoked contractions and relaxations, lasting up to 10 days after IM. This was associated with a reduced expression of chat and nos1 genes.

CONCLUSIONS & INFERENCES

Intestinal manipulation induces two waves of smooth muscle inhibition, most likely mediated by inflammatory cytokines, lasting up to 3 days after IM. Further, we here identify a late third phase (>24 h) characterized by impaired cholinergic and nitrergic neurotransmission persisting after recovery of muscle contractility. These findings illustrate that POI results from inflammation-mediated impaired smooth muscle contraction, but also involves a long-lasting impact of IM on the enteric nervous system.

Prediction of Prolonged Postoperative Ileus After Radical Gastrectomy for Gastric Cancer: A Scoring System Obtained From a Prospective Study

Currently, there is a paucity of study investigating postoperative ileus in gastric cancer surgery. This prospective study aims to identify the risk factors for prolonged postoperative ileus (PPOI) and to use these risk factors to generate a risk stratification scoring system for the occurrence of PPOI.Patients who underwent radical gastrectomy for gastric cancer were included in this study. A multivariate logistic analysis was applied to identify independent risk factors for PPOI and to generate the scoring system. A receiver operating characteristic curve was generated and the area under the curve was calculated to demonstrate the predictive power of the scoring system.Finally, 296 patients were included and analyzed, of whom 96 (32.4%) developed PPOI. The multivariate analysis showed that age ≥65 years, operative duration ≥4 hours, tumor-node-metastasis (TNM) stage = III, open/converted operative technique, and total postoperative opiates dose (TOD) ≥0.3 mg/kg were independent risk factors for PPOI. Based on these factors, a risk stratification scoring system was generated, classified by low-risk (score 0-2), moderate-risk (score 3-4), and high-risk (score 5-6) groups. The incidence of PPOI increased by 7.5-fold from low-risk to high-risk group. The area under the curve of the scoring system was 0.841 (95% CI, 0.793-0.890), indicating a good predictive capability for the occurrence of PPOI.We have identified independent risk factors for the occurrence of PPOI and used these factors to construct a risk stratification scoring system.

Mast cell degranulation inhibits motor patterns of human ileum and sigmoid colon in vitro: relevance for postoperative ileus

BACKGROUND

Local release of mast cell proteases during gastrointestinal surgery is associated with the inhibition of motility and postoperative ileus (POI). We determined whether activation of intramuscular mast cell affects the motor patterns of the human ileum and colon and whether proteases are involved.

METHODS

Motor response of ileal and colonic circular muscle strips was measured in organ bath. Mast cell degranulation was induced by compound 48/80 (c48/80; 25-675 μg/mL). Motor response was quantified as tone, rhythmic phasic contractions (RPCs) and contractions to electric field stimulation (EFS; 40 Hz), and bethanechol-evoked contractions. Ketotifen (10(-6) mol/L) and a protease inhibitor cocktail (P8340) were used to evaluate the role of mast cell mediators.

KEY RESULTS

(a) c48/80 impaired the spontaneous and the electrically evoked motor response in small bowel and colonic strips (sigmoid colon EC50 : 460.0 μg/mL for RPCs and 8.9 μg/mL for electrically evoked contraction amplitudes) and bethanechol-evoked contractions. (b) Preincubation with ketotifen (10(-6) mol/L, 1 h) prevented the impairment of RPCs and EFS-evoked contractions in the sigmoid colon and ileum but not in the right colon. (c) Preincubation with P8340 also prevented the impairment of contractions in the sigmoid colon but not in the ileum or the right colon.

CONCLUSIONS & INFERENCES

Mast cell degranulation by c48/80 inhibits the spontaneous and the nerve-mediated motor response in the human ileum and colon. The effect is partially mediated by mast cell proteases and could be relevant in the pathophysiology of POI.

The contribution of mast cells to postoperative ileus in experimental and clinical studies

The persistent phase of postoperative ileus (POI) is mediated by inflammatory activation of the resident myeloid immune cell population in the gut wall, likely elicited by neurogenic activation. Mast cells are thought to play a critical role in this inflammatory response and involvement of mast cells in POI has been investigated and described thoroughly in experimental studies. Intestinal manipulation (IM) leads to degranulation of mast cells, resulting in an increase in mast cell proteases in peritoneal fluid and gut tissue. The inflammatory infiltrate formed in the intestinal wall thereby impairs gastrointestinal motility. In the clinical study by Berdun et al., the experimentally known association between mast cell degranulation and delayed motility is shown in a clinical setting. These findings are important and open up therapeutic opportunities to reduce or prevent POI. In this mini-review, the role of mast cells in POI is discussed. Furthermore, an update is given on the involvement of the inflammatory response in POI and potential therapeutic strategies.

Clinical endpoint, early detection, and differential diagnosis of postoperative ileus: a systematic review of the literature

BACKGROUND

This systematic review summarizes evidence regarding clinical endpoints, early detection, and differential diagnosis of postoperative ileus (POI).

METHODS

Using MEDLINE, EMBASE, Cochrane, and Web-of-Science, we identified 2,084 articles. Risk of bias and level of evidence (LOE) of the included articles were determined, and relevant results were summarized.

RESULTS

Eleven articles were included, most of which with substantial risks of bias. Bowel motility studies revealed that defecation together with solid food tolerance is the most representative clinical endpoint of POI (LOE: 2b); other clinical signs (e.g. bowel sounds, passage of flatus) did not correlate with a full recovery of bowel motility. Inflammatory parameters including interleukin (IL)-6, IL-1, and TNF-α might assist in an early detection of prolonged POI (LOE: 4). Clinical manifestations (e.g. nausea, vomiting, abdominal distension, bowel sounds, flatus) and X-ray examinations provided limited aid to the differential diagnosis of POI, while CT with Gastrografin had the best specificity and sensitivity (both 100%; LOE: 1c).

CONCLUSIONS

Postoperative defecation together with tolerance of solid food intake seems to be the best clinical endpoint of POI. CT has the best differential diagnostic value between POI and other complications. Prospective studies with a high LOE are in great need.

Fabrication and implantation of miniature dual-element strain gages for measuring in vivo gastrointestinal contractions in rodents

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an area of productive research with over 1,400 published animal studies in just the last 5 years. Numerous techniques have been developed for quantifying smooth muscle activity of the stomach, small intestine, and colon. In vitro and ex vivo techniques offer powerful tools for mechanistic studies of GI function, but outside the context of the integrated systems inherent to an intact organism. Typically, measuring in vivo smooth muscle contractions of the stomach has involved an anesthetized preparation coupled with the introduction of a surgically placed pressure sensor, a static pressure load such as a mildly inflated balloon or by distending the stomach with fluid under barostatically-controlled feedback. Yet many of these approaches present unique disadvantages regarding both the interpretation of results as well as applicability for in vivo use in conscious experimental animal models. The use of dual element strain gages that have been affixed to the serosal surface of the GI tract has offered numerous experimental advantages, which may continue to outweigh the disadvantages. Since these gages are not commercially available, this video presentation provides a detailed, step-by-step guide to the fabrication of the current design of these gages. The strain gage described in this protocol is a design for recording gastric motility in rats. This design has been modified for recording smooth muscle activity along the entire GI tract and requires only subtle variation in the overall fabrication. Representative data from the entire GI tract are included as well as discussion of analysis methods, data interpretation and presentation.

Endogenous vagal activation dampens intestinal inflammation independently of splenic innervation in postoperative ileus

Postoperative ileus is encountered by patients undergoing open abdominal surgery and is characterized by intestinal inflammation associated with impaired gastrointestinal motility. We recently showed that inflammation of the gut muscularis triggered activation of the vagal efferent pathway mainly targeting the inflamed zone. In the present study we investigate further the modulatory role of endogenous activation of the vagal motor pathway on the innate immune response. Intestinal or splenic denervation was performed two weeks prior to intestinal manipulation (IM) or laparotomy (L). Twenty-four hour post-surgery, the gastrointestinal transit, immune cell influx, and pro-inflammatory cytokine levels were measured in the gut muscularis. Manipulation of the small intestine led to a delay in intestinal transit, an influx of leukocytes and increased pro-inflammatory cytokine expression. Surgical lesion of the vagal branch that selectively innervates the small intestine did not further delay the intestinal transit but significantly enhanced the expression levels of the pro-inflammatory cytokines IL-1β and IL-6 in the gut muscularis. Splenic denervation did not affect intestinal inflammation or gastrointestinal transit after intestinal manipulation. Our study demonstrates that selective vagotomy, leaving the splenic innervation intact, increases surgery-induced intestinal inflammation. These data suggest that endogenous activation of the vagal efferent pathway by intestinal inflammation directly dampens the local immune response triggered by intestinal manipulation independently of the spleen.

The spleen responds to intestinal manipulation but does not participate in the inflammatory response in a mouse model of postoperative ileus

Background

Postoperative ileus is characterized by a transient impairment of the gastrointestinal motility after abdominal surgery. The intestinal inflammation, triggered by handling of the intestine, is the main factor responsible for the prolonged dysmotility of the gastrointestinal tract. Secondary lymphoid organs of the intestine were identified as essential components in the dissemination of inflammation to the entire gastrointestinal tract also called field effect. The involvement of the spleen, however, remains unclear.

Aim

In this study, we investigated whether the spleen responds to manipulation of the intestine and participates in the intestinal inflammation underlying postoperative ileus.

Methods

Mice underwent Laparotomy (L) or Laparotomy followed by Intestinal Manipulation (IM). Twenty-four hours later, intestinal and colonic inflammation was assessed by QPCR and measurement of the intestinal transit was performed. Analysis of homeostatic chemokines in the spleen was performed by QPCR and splenic cell populations analysed by Flow Cytometry. Blockade of the egress of cells from the spleen was performed by administration of the Sphingosine-1-phosphate receptor 1 (S1P₁) agonist CYM-5442 10 h after L/IM.

Results

A significant decrease in splenic weight and cellularity was observed in IM mice 24 h post-surgery, a phenomenon associated with a decreased splenic expression level of the homeostatic chemokine CCL19. Splenic denervation restored the expression of CCL19 and partially prevented the reduction of splenocytes in IM mice. Treatment with CYM-5442 prevented the egress of splenocytes but did not ameliorate the intestinal inflammation underlying postoperative ileus.

Conclusions

Intestinal manipulation results in two distinct phenomena: local intestinal inflammation and a decrease in splenic cellularity. The splenic response relies on an alteration of cell trafficking in the spleen and is partially regulated by the splenic nerve. The spleen however does not participate in the intestinal inflammation during POI.

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.