Molecular and cellular mechanisms underlying postoperative paralytic ileus by various immune cell types

Fucoidan improves intestinal peristaltic function in rats with postoperative ileus

The effect of fucoidan on postoperative ileus (POI) has not been studied. In this study, how fucoidan ameliorates POI in a rat POI model was investigated. The results showed that in the model animals, when the first defecation time was prolonged, the amount of food consumed decreased, the small intestinal propulsion rate dramatically slowed, and the motility index (MI%) of the small intestine decreased. In vitro experiments revealed that the contractile response of small intestinal smooth muscle strips to carbachol (CCh) was reduced. Immunohistochemistry revealed evident macrophage infiltration in the intestinal muscularis. However, after oral pretreatment with fucoidan, the time to first defecation decreased, and food intake, the small intestinal propulsion rate, and MI% of the small intestine increased. Additionally, the contractile response of the intestinal strips to CCh became stronger, and macrophage infiltration decreased. Mechanistically, fucoidan alleviated POI by exerting anti-inflammatory and antioxidant effects as well as likely through the TrkB/ERK1/2/Akt signalling pathways. When POI occurred, the expression levels of inflammatory factors in the intestines significantly increased while the phosphorylation of TrkB, ERK1/2, and Akt significantly decreased; malondialdehyde (MDA) levels in the intestines increased but the levels of superoxide dismutase (SOD) and glutathione (GSH) decreased. In contrast, after pretreatment with fucoidan, the expression levels of inflammatory factors decreased; the phosphorylation levels of TrkB, ERK1/2, and Akt increased; the MDA level decreased; and SOD and GSH levels increased. Thus, fucoidan alleviated POI-induced impairment of rat intestinal motility through anti-inflammatory and antioxidant effects possibly associated with the TrkB/ERK1/2 and Akt signalling pathways.

Docosahexaenoic acid (DHA) promotes recovery from postoperative ileus and the repair of the injured intestinal barrier through mast cell-nerve crosstalk

The objective of this study was to investigate the neuroimmune mechanisms implicated in the enhancement of gastrointestinal function through the administration of oral DHA. Mast cell-deficient mice (KitW-sh) and C57BL/6 mice were used to establish postoperative ileus (POI) models. To further validate our findings, we conducted noncontact coculture experiments involving dorsal root ganglion (DRG) cells, bone marrow-derived mast cells (BMMCs) and T84 cells. Furthermore, the results obtained from investigations conducted on animals and cells were subsequently validated through clinical trials. The administration of oral DHA had ameliorative effects on intestinal barrier injury and postoperative ileus. In a mechanistic manner, the anti-inflammatory effect of DHA was achieved through the activation of transient receptor potential ankyrin 1 (TRPA1) on DRG cells, resulting in the stabilization of mast cells and increasing interleukin 10 (IL-10) secretion in mast cells. Furthermore, the activation of the pro-repair WNT1-inducible signaling protein 1 (WISP-1) signaling pathways by mast cell-derived IL-10 resulted in an enhancement of the intestinal barrier integrity. The current study demonstrated that the neuroimmune interaction between mast cells and nerves played a crucial role in the process of oral DHA improving the intestinal barrier integrity of POI, which further triggered the activation of CREB/WISP-1 signaling in intestinal mucosal cells.

The effect of early oral postoperative feeding on the recovery of intestinal motility after gastrointestinal surgery: a systematic review and meta-analysis of randomized clinical trials

Background and aims

Postoperative ileus is a frequent condition, leading to complications and a longer hospital stay. Few studies have demonstrated the benefit of early oral feeding in preventing ileus after gastrointestinal surgery. This study aims to evaluate the efficacy of early versus delayed oral feeding on the recovery of intestinal motility, length of hospital stay, and complications.

Methods

We conducted a systematic review and meta-analysis of randomized control trials, searching PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, and the ClincalTrials.gov until 31 December 2022. We evaluated the first passage of the stool, the first flatus, complications, length of postoperative stay, and vomiting. We assessed the risk of bias using the Cochrane risk of bias tool (version 2) for randomized trials and the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation methodology.

Results

We included 34 studies with a median sample size of 102 participants. With a moderate certainty of the evidence, the early oral feeding may reduce the time taken for the first passage of the stool (MD -0.99 days; CI 95% -1.25, -0.72), the first flatus (MD -0.70 days; CI 95% -0.87, -0.53), and the risk of complications (RR 0.69; CI 95% 0.59-0.80), while with a low certainty of evidence, it may reduce the length of stay (MD -1.31 days; CI 95% -1.59, -1.03). However, early feeding likely does not affect the risk of vomiting (RR 0.90; CI 95% 0.68, 1.18).

Conclusion

This review suggests that early oral feeding after gastrointestinal surgery may lead to a faster intestinal recovery, shorter postoperative stays, and fewer complications. However, careful interpretation is needed due to high heterogeneity and the moderate-to-low quality of evidence. Future studies should focus on the type and starting time of early oral feeding.

New insights into muscularis macrophages in the gut: from their origin to therapeutic targeting

Muscularis macrophages, as the most abundant immune cells in the intestinal muscularis externa, exhibit tissue protective phenotype in the steady state. Owing to tremendous advances in technology, we now know the fact that muscularis macrophages are a heterogeneous population of cells which could be divided into different functional subsets depending on their anatomic niches. There is emerging evidence showing that these subsets, through molecular interactions with their neighbours, take part in a wide range of physiological and pathophysiological processes in the gut. In this review, we summarize recent progress (particularly over the past 4 years) on distribution, morphology, origin and functions of muscularis macrophages and, where possible, the characteristics of specific subsets in response to the microenvironment they occupy, with particular emphasis on their role in muscular inflammation. Furthermore, we also integrate their role in inflammation-related gastrointestinal disorders, such as post-operative ileus and diabetic gastroparesis, in order to propose future therapeutic strategies.

Involvement of iNOS-induced reactive enteric glia cells in gastrointestinal motility disorders of postoperative Ileus mice

Postoperative ileus (POI) is the cessation or reduction of gastrointestinal (GI) motility after surgery. Reactive enteric glial cells (EGCs) are critical for maintaining bowel function. However, the triggering mechanisms and downstream effects of reactive EGCs in POI were poorly understood. The goal of this current study was to investigate whether the inducible nitric oxide synthase (iNOS)-driven reactive EGCs participated in GI motility disorders and mechanisms underlying altered GI motility in POI. Intestinal manipulation (IM)-induced POI mice and iNOS-/- mice were used in the study. Longitudinal muscle and myenteric plexuses (LMMPs) from the distal small intestine were stained by immunofluorescence. Our results found that the GI motility disorders occurred in the IM-induced POI mice, and reactive EGCs were observed in LMMPs. Glial metabolic inhibitor gliotoxin fluorocitrate (FC) treatment or iNOS gene knockout attenuated GI motility dysfunction. In addition, we also found that FC treatment or iNOS gene knockout significantly inhibited the fluorescence intensity macrophage colony-stimulating factor (M-CSF), which reduced M2 phenotype macrophages activation in LMMPs of IM-induced POI mice. Our findings demonstrated that iNOS-driven reactive EGCs played a key role and were tightly linked to the MMs homeostasis in the POI mice. EGCs are emerging as a new frontier in neurogastroenterology and a potential therapeutic target.

Nomogram for predicting prolonged postoperative ileus in colorectal cancer based on age and inflammatory markers

Aim: To explore the relationship between inflammatory markers and prolonged postoperative ileus (PPOI), and to establish a nomogram for predicting PPOI. Patients & methods: The data of 229 patients were analyzed retrospectively. Univariate and multivariate logistic regression analysis were used to analyze the risk factors affecting the occurrence of PPOI. The predictive model of PPOI was established and verified internally. Results: Postoperative PPOI occurred in 87 (38.0%) of all 229 patients. Our study showed that age, preoperative neutrophil-lymphocyte ratio and changes in neutrophil-lymphocyte ratio were independent risk factors for PPOI. Conclusion: The nomograms established based on these independent risk factors have good predictive efficacy and may be able to guide clinicians to individualize the diagnosis and treatment.

Paralytic Ileus during Treatment of Pulmonary and Renal Tuberculosis in a Non-Human Immunodeficiency Virus Patient: An Unusual Presentation of Tuberculosis-immune Reconstitution Inflammatory Syndrome

Paralytic ileus as tuberculosis-immune reconstitution inflammatory syndrome (TB-IRIS) is extremely rare. We herein report a 44-year-old man with pulmonary and renal tuberculosis who developed paralytic ileus 14 days after starting antituberculosis therapy (ATT) despite an initial favorable response to ATT. Paralytic ileus was successfully managed with conservative care. He initially required hemodialysis because of obstructive uropathy due to renal tuberculosis, but he was able to withdraw from dialysis after placement of ureteral stents. TB-IRIS can affect organs other than the original sites of tuberculosis, and the combined use of steroids may be effective for its prevention and treatment.