Inflammation, Impaired Motility, and Permeability in a Guinea Pig Model of Postoperative Ileus

The Effect of CKD-495, Eupacidin, and Their Marker Compounds on Altered Permeability in a Postoperative Ileus Animal Model

Background and Objectives: Postoperative ileus (POI) is a delay in gastrointestinal transit following surgery that leads to various complications. There is limited understanding of its effective treatment options. CKD-495 and eupacidin are natural products licensed for treating mucosal lesions in acute and chronic gastritis; however, little is known about their effects on intestinal permeability. This study evaluated the effects of CKD-495, eupacidin, and its components (eupatilin and cinnamic acid) on intestinal permeability in an animal model of POI. Materials and Methods: Guinea pigs underwent surgical procedures and were randomly assigned to different treatment groups. Drugs were administered orally prior to surgery. Intestinal permeability, leukocyte count, and the expression of calprotectin and tight junction proteins were measured in the harvested ileum tissue. Results: The intestinal permeability and leukocyte count were higher in the POI group than in the control group. The pre-administration of CKD-495, cinnamic acid, eupacidin, and eupatilin effectively prevented these changes in the POI model. No significant differences were observed in the expression of tight junction proteins. Conclusions: CKD-495, cinnamic acid, eupacidin, and eupatilin exerted protective effects against increased intestinal permeability and inflammation in an animal model of POI. These natural products have potential as therapeutic options for the treatment of POI.

Alterations of Prostanoid Expression and Intestinal Epithelial Barrier Functions in Ileus

INTRODUCTION

Intestinal manipulation (IM)-induced inflammation could contribute to postoperative ileus (POI) pathophysiology via the modulation of prostanoid pathways. To identify the prostanoids involved, we aimed to characterize the profile of prostanoids and their synthesis enzyme expression in a murine model of POI and to determine whether the altered prostanoids could contribute to POI.

METHODS

Four or 14 h after IM in mice, gastrointestinal (GI) motility and intestinal epithelial barrier (IEB) permeability were assessed in vivo and ex vivo in Ussing chambers. Using high sensitivity liquid chromatography-tandem mass spectrometry, we characterized the tissue profile of polyunsaturated fatty acid metabolites in our experimental model. Finally, we evaluated in vivo the effects of the prostanoids studied upon IM-induced gut dysfunctions.

RESULTS

We first showed that 14 h after IM was significantly faster than jejunal transit at 4 h post-IM, although it remained significantly increased compared to the control. In contrast, we showed that IM-induced inflammation increase in jejunum permeability was similar after four and 14 h. We next showed that expression of prostacyclin synthase and hemopoietic prostaglandin-D synthase mRNA and their products were significantly reduced 14 h after IM as compared to controls. Furthermore, 15-deoxy-delta 12,14-Prostaglandin J2 reduced the IM-induced inflammation increase in IEB permeability but had no effect on GI motility. In contrast, PGI2 increased IM-induced IEB permeability and motility dysfunctions.

CONCLUSIONS

Arachidonic acid derivative contributes differentially to GI dysfunction in POI. The decrease of 15-deoxy-delta 12,14-Prostaglandin J2 levels induced by IM could contribute to impaired GI dysfunctions in POI and could be considered as putative therapeutic targets to restore barrier dysfunctions associated with POI.

A critical role for erythropoietin on vagus nerve Schwann cells in intestinal motility

BACKGROUND

Dysmotility and postoperative ileus (POI) are frequent major clinical problems post-abdominal surgery. Erythropoietin (EPO) is a multifunctional tissue-protective cytokine that promotes recovery of the intestine in various injury models. While EPO receptors (EPOR) are present in vagal Schwann cells, the role of EPOR in POI recovery is unknown because of the lack of EPOR antagonists or Schwann-cell specific EPOR knockout animals. This study was designed to explore the effect of EPO via EPOR in vagal nerve Schwann cells in a mouse model of POI.

RESULTS

The structural features of EPOR and its activation by EPO-mediated dimerization were understood using structural analysis. Later, using the Cre-loxP system, we developed a myelin protein zero (Mpz) promoter-driven knockout mouse model of Schwann cell EPOR (MpzCre-EPOR^flox/flox / Mpz-EPOR-KO) confirmed using PCR and qRT-PCR techniques. We then measured the intestinal transit time (ITT) at baseline and after induction of POI with and without EPO treatment. Although we have previously shown that EPO accelerates functional recovery in POI in wild type mice, EPO treatment did not improve functional recovery of ITT in POI of Mpz-EPOR-KO mice.

CONCLUSIONS

To the best of our knowledge, this is the first pre-clinical study to demonstrate a novel mouse model of EPOR specific knock out on Schwan cells with an effect in the gut. We also showed novel beneficial effects of EPO through vagus nerve Schwann cell-EPOR in intestinal dysmotility. Our findings suggest that EPO-EPOR signaling in the vagus nerve after POI is important for the functional recovery of ITT.

Inflammation and Impaired Gut Physiology in Post-operative Ileus: Mechanisms and the Treatment Options

Post-operative ileus (POI) is the transient cessation of coordinated gastrointestinal motility after abdominal surgical intervention. It decreases quality of life, prolongs length of hospital stay, and increases socioeconomic costs. The mechanism of POI is complex and multifactorial, and has been broadly categorized into neurogenic and inflammatory phase. Neurogenic phase mediated release of corticotropin-releasing factor (CRF) plays a central role in neuroinflammation, and affects both central autonomic response as well hypothalamic-pituitary-adrenal (HPA) axis. HPA-stress axis associated cortisol release adversely affects gut microbiota and permeability. Peripheral CRF (pCRF) is a key player in stress induced gastric emptying and colonic transit. It functions as a local effector and interacts with the CRF receptors on the mast cell to release chemical mediators of inflammation. Mast cells proteases disrupt epithelial barrier via protease activated receptor-2 (PAR-2). PAR-2 facilitates cytoskeleton contraction to reorient tight junction proteins such as occludin, claudins, junctional adhesion molecule, and zonula occludens-1 to open epithelial barrier junctions. Barrier opening affects the selectivity, and hence permeation of luminal antigens and solutes in the gastrointestinal tract. Translocation of luminal antigens perturbs mucosal immune system to further exacerbate inflammation. Stress induced dysbiosis and decrease in production of short chain fatty acids add to the inflammatory response and barrier disintegration. This review discusses potential mechanisms and factors involved in the pathophysiology of POI with special reference to inflammation and interlinked events such as epithelial barrier dysfunction and dysbiosis. Based on this review, we recommend CRF, mast cells, macrophages, and microbiota could be targeted concurrently for efficient POI management.

Pre-habilitation before colorectal cancer surgery could improve postoperative gastrointestinal function recovery: a case-matched study

PURPOSE

While its effect is controverted, multimodal pre-habilitation could be used to improve the postoperative course following colorectal cancer surgery. However, by increasing lean body mass, pre-habilitation could reduce the time needed to recover gastrointestinal (GI) functions. The aim was to assess the impact of pre-habilitation before colorectal cancer surgery on postoperative GI motility recovery.

METHODS

This is a matched retrospective study based on a prospective database including patients undergoing colorectal surgery without pre-habilitation (NPH) (2016-2018) and with pre-habilitation (PH group) (2018-2019). The main outcome measure was the time to GI-3 recovery (tolerance to solid food and flatus and/or stools).

RESULTS

One hundred thirteen patients were included, 37 underwent pre-habilitation (32.7%). The patient's age, the surgical procedure, the surgical access, the rate of synchronous metastasis, the rate of preoperative chemoradiotherapy, and the rate of stoma were more important in the PH group. Conversely, the rate of patients with an ASA score of > 2 was higher in the NPH group. By matching patients according to age, gender and surgical procedure, 84 patients were compared (61 in the NPH group and 23 in the PH group). The mean of GI-3 recovery was significantly lower in the PH group. The other endpoints were not significantly different but time to GI function recovery and medical morbidity tended to be higher in the NPH group. Compliance with the enhanced recovery program was significantly higher in the PH group.

CONCLUSION

Pre-habilitation before colorectal cancer surgery reduced time to GI function recovery and may increase compliance with the enhanced recovery program.

Altered Intestinal Permeability and Drug Repositioning in a Post-operative Ileus Guinea Pig Model

Background/Aims

The aim of this study is to identify the alteration in intestinal permeability with regard to the development of post-operative ileus (POI). Moreover, we investigated drug repositioning in the treatment of POI.

Methods

An experimental POI model was developed using guinea pigs. To measure intestinal permeability, harvested intestinal membranes of the ileum and proximal colon was used in an Ussing chamber. To identify the mechanisms associated with altered permeability, we measured leukocyte count and expression of calprotectin, claudin-1, claudin-2, and mast cell tryptase. We compared control, POI, and drug groups (mosapride [0.3 mg/kg and 1 mg/kg, orally], glutamine [500 mg/kg, orally], or ketotifen [1 mg/kg, orally] with regard to these parameters.

Results

Increased permeability after surgery significantly decreased after administration of mosapride, glutamine, or ketotifen. Leukocyte counts increased in the POI group and decreased significantly after administration of mosapride (0.3 mg/kg) in the ileum, and mosapride (0.3 mg/kg and 1 mg/kg), glutamine, or ketotifen in the proximal colon. Increased expression of calprotectin after surgery decreased after administration of mosapride (0.3 mg/kg), glutamine, or ketotifen in the ileum and proximal colon, and mosapride (1 mg/kg) in the ileum. The expression of claudin-1 decreased significantly and that of claudin-2 increased after operation. After administration of glutamine, the expression of both proteins was restored. Finally, mast cell tryptase levels increased in the POI group and decreased significantly after administration of ketotifen.

Conclusions

The alteration in intestinal permeability is one of the factors involved in the pathogenesis of POI. We repositioned 3 drugs (mosapride, glutamine, and ketotifen) as novel therapeutic agents for POI.

Present and Future Therapeutic Approaches to Barrier Dysfunction

There is converging and increasing evidence, but also uncertainty, for the role of abnormal intestinal epithelial barrier function in the origin and development of a growing number of human gastrointestinal and extraintestinal inflammatory disorders, and their related complaints. Despite a vast literature addressing factors and mechanisms underlying changes in intestinal permeability in humans, and its connection to the appearance and severity of clinical symptoms, the ultimate link remains to be established in many cases. Accordingly, there are no directives or clinical guidelines related to the therapeutic management of intestinal permeability disorders that allow health professionals involved in the management of these patients to carry out a consensus treatment based on clinical evidence. Instead, there are multiple pseudoscientific approaches and commercial propaganda scattered on the internet that confuse those affected and health professionals and that often lack scientific rigor. Therefore, in this review we aim to shed light on the different therapeutic options, which include, among others, dietary management, nutraceuticals and medical devices, microbiota and drugs, and epigenetic and exosomes-manipulation, through an objective evaluation of the scientific publications in this field. Advances in the knowledge and management of intestinal permeability will sure enable better options of dealing with this group of common disorders to enhance quality of life of those affected.

Intestinal Barrier, Claudins and Mycotoxins

The intestinal barrier is the main barrier against all of the substances that enter the body. Proper functioning of this barrier guarantees maintained balance in the organism. Mycotoxins are toxic, secondary fungi metabolites, that have a negative impact both on human and animal health. It was postulated that various mycotoxins may affect homeostasis by disturbing the intestinal barrier. Claudins are proteins that are involved in creating tight junctions between epithelial cells. A growing body of evidence underlines their role in molecular response to mycotoxin-induced cytotoxicity. This review summarizes the information connected with claudins, their association with an intestinal barrier, physiological conditions in general, and with gastrointestinal cancers. Moreover, this review also includes information about the changes in claudin expression upon exposition to various mycotoxins.

Ileus in Acute Pancreatitis Correlates with Severity of Pancreatitis, Not Volume of Fluid Resuscitation or Opioid Use: Observations from Mid-West Cohort

The recovery of gastrointestinal functions is an important determinant of course of acute pancreatitis and the timing of hospital discharge. Here, we evaluated association between fluid resuscitation volume and opioid use with clinically significant ileus development in patients with acute pancreatitis. Consecutive adults admitted with acute pancreatitis between January 2014 and December 2019 to our academic and two community hospital were included. The Bedside Index for Severe Acute Pancreatitis (BISAP) and systemic inflammatory response syndrome (SIRS) were used to predict severity of pancreatitis based on their readily availability. Severity of pancreatitis was determined based on the Revised Atlanta classification. Fluid resuscitation volume and opioid use were collected as administered on day 1 and day 2.Clinically significant ileus was determined based on treating physician's assessment. Forty-nine (11%) of 441 unique patients included in the study developed clinically significant ileus. Demographics of patients with or without ileus were similar between the two groups. On univariate analysis, the presence of SIRS syndrome (< 0.001), a > 3 BISAP score (p < 0.001), and severity of pancreatitis (p < 0.001) were associated with ileus, mean fluid resuscitation volume (5.6L vs 5.5L, p = 0.888) and cumulative median morphine-equivalent units (12 vs 12, p = 0.232) on day 1 and day 2 were not. However, ileus development was associated with increased hospital length of stay and admission to intensive care unit. On observations, clinically significant ileus development is associated with severity of acute pancreatitis, not with fluid resuscitation volume or opioid analgesia dose used in current standard of care.

An altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of postoperative ileus

BACKGROUND

The aim of this study is to investigate the altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of the postoperative ileus (POI).

METHODS

A laparotomy with cecal manipulation was performed to induce POI in guinea pigs. Fecal pellets were collected before the operation (the baseline) and 1, 3, and 5 days after the operation. The extracted fecal DNA was amplified and sequenced using the Illumina MiSeq sequencing system. The same POI procedures were performed after oral pretreatment of the probiotics for 7 days before operation. The effect of the probiotics on the selected taxa and fecal acetate were evaluated, as were the butyrate levels. The colonic transit was assessed by measurement of the fecal pellet output.

KEY RESULTS

The communities of the baseline and POI groups indicated significantly distinct composition. The genera Bifidobacterium and Lactobacillus were more abundant in the baseline group compared with the POI groups, and Bacteroides and Blautia were more abundant in the POI groups. Decreased abundances of the species Bifidobacterium bifidum and Bifidobacterium longum after the POI procedure were significantly increased in the probiotics group. The decreased fecal butyrate level after the POI procedure was significantly increased, and colonic transit was significantly improved in the probiotics group.

CONCLUSIONS AND INFERENCES

POI induces gut bacterial dysbiosis. Moreover, pretreatment of probiotics before operation restores the beneficial bacterial species, butyrate production, and bowel movement. The modulation of gut microbiota may help the treatment and prevention of POI.

Early oral nutrition improves postoperative ileus through the TRPA1/CCK1-R-mediated mast cell-nerve axis

Background

The mechanism of early oral nutrition that regulates the mast cell-nerve axis to improve postoperative ileus (POI) remains unclear. This study aims to investigate whether early oral nutrition can improve POI through Transient receptor potential ankyrin-1 (TRPA1)/cholecystokinin 1 receptor (CCK1-R) in the mast cell-nerve axis.

Methods

Experiment 1: Male Sprague-Dawley (SD) rats were randomly divided into the TRPA1 inhibitor + oral nutrition group (TI + ON + POI), oral nutrition group (ON + POI), POI group (POI) and sham surgery group (Sham). Nine rats in each group were treated. Experiment 2: Primary cultures of mast cells and dorsal root ganglion cells were created, and a non-contact co-culture system was established. The cells were divided into the dorsal root ganglion (DRG) group, mast cell group, DRG + mast cell group, TRPA1 inhibitor or enhancer group, mast cell stabilizer or enhancer group, CCK1-R inhibitor or enhancer group. The results of expression of TRPA1, CCK1-R and histamine in colon tissue, portal vein blood, supernatant or dorsal root ganglia, intestinal transport test and mast cell morphology were analysed.

Results

In experiment 1, Early oral nutrition could alleviate the degranulation and activation of mast cells and alleviate the inflammatory reaction of intestinal wall muscles (P<0.05). Early oral nutrition improved POI by stabilizing mast cells with TRPA1. TRPA1 inhibitor decreased CCK1-R concentrations in portal vein blood and CCK1-R expression in colonic smooth muscle (P<0.05). In experiment 2, the change in mast cell function regulated the secretion of CCK1-R by neurons, CCK1-R negatively regulated the degranulation and activation of mast cells (P<0.05), and mast cells positively regulated the expression of TRPA1 protein in DRG (P<0.05).

Conclusions

Early enteral nutrition can improve POI through the TRPA1/CCK1-R-mediated mast cell-nerve axis. TRPA1 positively regulates CCK1-R to stabilize mast cells, but TRPA1 is not the target of the downstream CCK1-R pathway.

Effects of 17β-Estradiol on Colonic Permeability and Inflammation in an Azoxymethane/Dextran Sulfate Sodium-Induced Colitis Mouse Model

Background/Aims

Intestinal barrier dysfunction is a hallmark of inflammatory bowel diseases (IBDs) such as ulcerative colitis. This dysfunction is caused by increased permeability and the loss of tight junctions in intestinal epithelial cells. The aim of this study was to investigate whether estradiol treatment reduces colonic permeability, tight junction disruption, and inflammation in an azoxymethane (AOM)/dextran sodium sulfate (DSS) colon cancer mouse model.

Methods

The effects of 17β-estradiol (E2) were evaluated in ICR male mice 4 weeks after AOM/DSS treatment. Histological damage was scored by hematoxylin and eosin staining and the levels of the colonic mucosal cytokine myeloperoxidase (MPO) were assessed by enzyme-linked immunosorbent assay (ELISA). To evaluate the effects of E2 on intestinal permeability, tight junctions, and inflammation, we performed quantitative real-time polymerase chain reaction and Western blot analysis. Furthermore, the expression levels of mucin 2 (MUC2) and mucin 4 (MUC4) were measured as target genes for intestinal permeability, whereas zonula occludens 1 (ZO-1), occludin (OCLN), and claudin 4 (CLDN4) served as target genes for the tight junctions.

Results

The colitis-mediated induced damage score and MPO activity were reduced by E2 treatment (p<0.05). In addition, the mRNA expression levels of intestinal barrier-related molecules (i.e., MUC2, ZO-1, OCLN, and CLDN4) were decreased by AOM/DSS-treatment; furthermore, this inhibition was rescued by E2 supplementation. The mRNA and protein expression of inflammation-related genes (i.e., KLF4, NF-κB, iNOS, and COX-2) was increased by AOM/DSS-treatment and ameliorated by E2.

Conclusions

E2 acts through the estrogen receptor β signaling pathway to elicit anti-inflammatory effects on intestinal barrier by inducing the expression of MUC2 and tight junction molecules and inhibiting pro-inflammatory cytokines.

Corticotrophin-releasing factor-mediated effects of DA-9701 in Postoperative Ileus Guinea Pig Model

BACKGROUND

Postoperative ileus (POI) is abdominal surgery-induced impaired gastrointestinal (GI) motility. We aimed to investigate the effects of DA-9701, a prokinetic agent formulated from Pharbitis Semen and Corydalis tuber, likely mediated via corticotrophin-releasing factor (CRF) pathways, in a POI model.

METHODS

A laparotomy with cecal manipulation was performed to induce POI in guinea pigs. GI transit was measured based on charcoal migration after intragastric administration of DA-9701 1, 3, and 10 mg kg^-1 . CRF1 receptor antagonist, CP-154 526 (subcutaneous) or agonist, human/rat (h/r) CRF (intraperitoneal) was injected. Then, plasma adrenocorticotropic hormone (ACTH) levels were measured, and the average intensity of the CRF expression was analyzed in the proximal colon and hypothalamus, and c-Fos in the hypothalamus.

KEY RESULTS

DA-9701 significantly increased delayed GI transit in POI in a dose-dependent manner and decreased plasma ACTH levels at 10 mg kg^-1 . CP-154 526 significantly decreased plasma ACTH levels but was not as effective on GI transit as DA-9701 was. h/r CRF did not significantly affect GI transit and plasma ACTH levels. No significant difference was observed in GI transit and plasma ACTH levels in both groups administered DA-9701 with h/r CRF and h/r CRF alone. CRF expression in the proximal colon decreased after DA-9701 administration, but not significantly, compared with levels in POI alone. However, CRF expression in the hypothalamus was significantly lower in the DA-9701-pretreated POI than in the untreated POI.

CONCLUSIONS AND INFERENCES

The DA-9701-induced improvement in GI transit and inhibition of plasma ACTH levels was mediated by the central CRF pathway.