Diversion of intestinal flow decreases the numbers of interleukin 4 secreting and interferon gamma secreting T lymphocytes in small bowel mucosa

[Morphological predictors of water-electrolyte disorders in patients with preventive ileostomy after rectal resection for cancer]

OBJECTIVE

To analyze morphological changes in wall of functioning and non-functioning small intestine in patients with preventive ileostomy and to determine histological predictors of water-electrolyte disorders.

MATERIAL AND METHODS

We prospectively analyzed 57 patients >18 years old who underwent rectal resection with preventive ileostomy between January 2022 and November 2023. Anthropometric data included gender, age, body mass index, ECOG and ASA classes. Complications associated with large losses through ileostomy were water-electrolyte disorders, dehydration and acute renal failure with repeated hospitalization. Morphological analysis implied intraoperative full-layer biopsy of small intestine on anterior abdominal wall (ileostomy). Intraoperative biopsy of efferent and afferent loops was also carried out. Tissue samples were examined by light microscopy. We analyzed mean height of mucous membrane villi and depth of crypts, as well as their ratio. Fibrosis and swelling of submucosa were evaluated too. The results were analyzed in the SPSS Statistics 20 software.

RESULTS

Mean height of intestinal villi <465 microns (p=0.028), ratio of their height to crypt depth <4.38 (p=0.034) and submucosal fibrosis (p=0.031) significantly affected malabsorption and readmission of patients. The risk of readmission was 11.5 and 5.5 times higher in univariate analysis. Multivariate analysis revealed in-hospital dehydration with resumption of infusion therapy as a predictor of readmission (p=0.046).

CONCLUSION

Ileostomy is a certain stress for the patient's body. Not every patient is able for adaptation. One of the adaptation mechanisms is hypertrophy of mucous membrane villi involved in digestion. This mechanism is less pronounced in patients with repeated hospitalizations. Preoperative morphological examination of ileum mucosa may be an additional objective predictor of possible complications of preventive ileostomy.

The Pathology and Physiology of Ileostomy

An ileostomy is a surgery that is commonly performed to protect low pelvic anastomoses or prevent high-risk anastomotic leakages. However, various postoperative complications remain of major concern. After an ileostomy, the distal intestinal segment is left open for an extended period and is in a non-functional state. Consequently, the intestinal mucosa, smooth muscle, and microbiota undergo significant changes that are closely related to postoperative recovery and complications. A systematic description of these changes is necessary to understand the relationship among them and take more effective measures for postoperative intervention.

Effects of intraepithelial lymphocyte-derived cytokines on intestinal mucosal barrier function

The mucosal surface of the gastrointestinal tract directly interacts with the mucosal lumen, which is continuously exposed to foreign antigens. Specialized intraepithelial lymphocytes (IELs), located between the basolateral surfaces of the epithelial cells, are important as the first line of defense against microbes as well as for their role in the maintenance of epithelial barrier homeostasis. Although IELs are mainly composed of T cells, they are phenotypically and functionally distinct from T cells in peripheral blood or the spleen. Not only are IELs stimulated by the antigens of the intestinal lumen but are they also stimulated by regulatory immune cells. The integrity of the intestinal mucosal barrier is closely tied to the IEL function. Cytokines produced by IELs modulate the cellular functions that trigger the downstream signaling pathways and mediate the barrier homeostasis. In this review, we will address the broad spectrum of cytokines that are derived from IELs and the functional regulation of these cytokines on the intestinal barrier.

Pitfalls in the interpretation of nonneoplastic mucosal biopsies in inflammatory bowel disease

This review provides a summary of common diagnostic problems encountered by both pathologists and gastroenterologists when evaluating patients with diarrhea and in whom inflammatory bowel disease (IBD) is suspected. The two most common forms of IBD, ulcerative colitis (UC) and Crohn's disease (CD), may, in certain settings, show overlapping endoscopic and pathologic features, potentially resulting in diagnostic confusion. For instance, some cases of UC may show unusual CD-like features, such as rectal sparing, discontinuous disease, aphthous ulceration, ileal or extracolonic involvement, and granulomatous inflammation, all of which may be evident in mucosal biopsy specimens. CD may also present as a diffuse, superficial pancolitis with ileal sparing that mimics the endoscopic and histologic appearance of UC. Furthermore, other forms of colitis, such as microscopic colitis, diverticulitis, diversion colitis, and nonsteroidal anti-inflammatory drug (NSAID)-induced colonic injury may also show IBD-like changes in mucosal biopsies. The potential diagnostic pitfalls faced by physicians, as well as features that aid in the distinction among these entities, are discussed in detail in this review.

Th2 Cytokines Down-Regulate TLR Expression and Function in Human Intestinal Epithelial Cells

TLRs serve important immune and nonimmune functions in human intestinal epithelial cells (IECs). Proinflammatory Th1 cytokines have been shown to promote TLR expression and function in IECs, but the effect of key Th2 cytokines (IL-4, IL-5, IL-13) on TLR signaling in IECs has not been elucidated so far. We stimulated human model IECs with Th2 cytokines and examined TLR mRNA and protein expression by Northern blotting, RT-PCR, real-time RT-PCR, Western blotting, and flow cytometry. TLR function was determined by I-kappaBalpha phosphorylation assays, ELISA for IL-8 secretion after stimulation with TLR ligands and flow cytometry for LPS uptake. IL-4 and IL-13 significantly decreased TLR3 and TLR4 mRNA and protein expression including the requisite TLR4 coreceptor MD-2. TLR4/MD-2-mediated LPS uptake and TLR ligand-induced I-kappaBalpha phosphorylation and IL-8 secretion were significantly diminished in Th2 cytokine-primed IECs. The down-regulatory effect of Th2 cytokines on TLR expression and function in IECs also counteracted enhanced TLR signaling induced by stimulation with the hallmark Th1 cytokine IFN-gamma. In summary, Th2 cytokines appear to dampen TLR expression and function in resting and Th1 cytokine-primed human IECs. Diminished TLR function in IECs under the influence of Th2 cytokines may protect the host from excessive TLR signaling, but likely also impairs the host intestinal innate immune defense and increases IEC susceptibility to chronic inflammation in response to the intestinal microenvironment. Taken together, our data underscore the important role of Th2 cytokines in balancing TLR signaling in human IECs.

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Expression of Th1/Th2 cytokines in intestinal mucosa of ulcerative colitis

AIM

To investigate the effects of the expression of Th1/Th2 cytokines in intestinal mucosa with ulcerative colitis.

METHODS

Thirty patients (24 males, 6 females, age 18-79 years) with severe ulcerative colitis (UC) were examined by colonoscope, the diagnosis was confirmed by histological method. Bacterial infection was excluded through consecutive stool cultures twice. And ameba, schistosomiasis, gastroen-terological cancer and endocrine diseases were also excluded. Ulcerative colitis was found in omni-colon (n = 15) , sigmoid (n = 9), rectum (n = 6), respectively. Its clinical categories included relapse (n = 20), persistent (n = 7) and initial (n = 3).They were treated by Sulphasalazine (SASP) and glucocorticoid after histological diagnosis. Eight weeks later, they were re-examined by colonoscope. The expression of cytokines in the intestinal mucosa of UC patients were detected by a semi-quantitative assay, reverse transcription-polymerase chain reaction(RT-PCR) before and after treatment respectively.

RESULTS

Comparison with control groups, the expression of TNF-α, IL-2 was increased but IL-4 was decreased in the intestinal mucosa in acute stage. Sulphasalazine (SASP) and glucocorticoid inhibited inflammation by reducing the expression of TNF-α from 1.22±0.02 to 0.78±0.08 (P<0.01) and of IL-2 from 0.82±0.06 to 0.47±0.04 (P<0.01), and elevate the expression of IL-10 from 0.68±0.03 to 0.91±0.02(P<0.01).

CONCLUSION

There is an imbalance of Th1 and Th2 phenotype cytokine in patients with ulcerative colitis.

SYSTEMIC AND LOCAL SECRETIONS OF CYTOKINES AND NITRIC OXIDE IN MASSIVE BOWEL RESECTED RATS WITH OR WITHOUT SMALL BOWEL SEGMENT REVERSAL

Our previous study suggested that small bowel segment reversal stimulates jejunal hyperplasia, but that the elevated serum interleukin (IL-)6 eliminates whole-body anabolism in massive bowel resected rats. The aim of this study was to investigate systemic and local secretions of cytokines and nitric oxide (NO) in relation to whole-body and tissue responses in rats that underwent massive bowel resection with small bowel segment reversal. Seventy percent small bowel resection was performed in Wistar rats with (REV) or without (CON) a 5 cm reversed small bowel segment. Sham operation (SHAM) was performed on a third group of rats. Twelve days after surgery the REV group had significantly lower weight gain and greater serum levels of NO, IL-2 and IL-6 than the CON and SHAM groups. The weights of the livers in the REV and CON groups were significantly heavier, but these groups had lower levels of protein, tumour-necrosis factor-alpha, IL-2 and IL-6 than the SHAM group. The cecum weights of the REV group were significantly higher with increased protein and NO levels, but decreased IL-6 levels compared with the CON and SHAM groups. In the proximal small intestine the REV group had significantly increased protein levels and mucosal dry weights, but decreased interferon-gamma and IL-2 compared with the CON and SHAM groups. Our results suggested that cytokines and NO may have endocrine and paracrine/autocrine actions in regulating whole-body and tissue responses.