Elevated basal intestinal mucosal cytokine levels in asymptomatic first-degree relatives of patients with Crohn’s disease

Nutritional Lipids and Mucosal Inflammation

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammation in the intestine. Given their role in regulation of inflammation, long-chain n-3 polyunsaturated fatty acids (PUFAs) represent a potential supplementary therapeutic approach to current drug regimens used for IBD. Mechanistically, there is ample evidence for an anti-inflammatory and pro-resolution effect of long-chain n-3 PUFAs after they incorporate into cell membrane phospholipids. They disrupt membrane rafts and when released from the membrane suppress inflammatory signaling by activating PPAR-γ and free fatty acid receptor 4; furthermore, they shift the lipid mediator profile from pro-inflammatory eicosanoids to specialized pro-resolving mediators. The allocation of long-chain n-3 PUFAs also leads to a higher microbiome diversity in the gut, increases short-chain fatty acid-producing bacteria, and improves intestinal barrier function by sealing epithelial tight junctions. In line with these mechanistic studies, most epidemiological studies support a beneficial effect of long-chain n-3 PUFAs intake on reducing the incidence of IBD. However, the results from intervention trials on the prevention of relapse in IBD patients show no or only a marginal effect of long-chain n-3 PUFAs supplementation. In light of the current literature, international recommendations are supported that adequate diet-derived n-3 PUFAs might be beneficial in maintaining remission in IBD patients.

Mend Your Fences: The Epithelial Barrier and its Relationship With Mucosal Immunity in Inflammatory Bowel Disease

The intestinal epithelium can be easily disrupted during gut inflammation as seen in inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn's disease. For a long time, research into the pathophysiology of IBD has been focused on immune cell-mediated mechanisms. Recent evidence, however, suggests that the intestinal epithelium might play a major role in the development and perpetuation of IBD. It is now clear that IBD can be triggered by disturbances in epithelial barrier integrity via dysfunctions in intestinal epithelial cell-intrinsic molecular circuits that control the homeostasis, renewal, and repair of intestinal epithelial cells. The intestinal epithelium in the healthy individual represents a semi-permeable physical barrier shielding the interior of the body from invasions of pathogens on the one hand and allowing selective passage of nutrients on the other hand. However, the intestinal epithelium must be considered much more than a simple physical barrier. Instead, the epithelium is a highly dynamic tissue that responds to a plenitude of signals including the intestinal microbiota and signals from the immune system. This epithelial response to these signals regulates barrier function, the composition of the microbiota, and mucosal immune homeostasis within the lamina propria. The epithelium can thus be regarded as a translator between the microbiota and the immune system and aberrant signal transduction between the epithelium and adjacent immune cells might promote immune dysregulation in IBD. This review summarizes the important cellular and molecular barrier components of the intestinal epithelium and emphasizes the mechanisms leading to barrier dysfunction during intestinal inflammation.

A subgroup of first-degree relatives of Crohn's disease patients shows a profile of inflammatory markers in the blood which is more typical of Crohn's disease patients than of normal individuals

Introduction. Family member with IBD is the greatest risk factor for developing the disease. The hematological profile of first-degree relatives (FDRs) of Crohn's disease (CD) patients was studied in order to identify healthy FDRs at risk to develop disease. Materials and methods. Thirty CD patients, 90 FDRs, and 28 non-related individuals (controls) were enrolled. Hematological profile and C-reactive protein were determined. Results. All hematological parameters were significantly different in CD patients compared to controls, with significantly higher levels of CRP, WBC, PMN, MONO, and PLT and lower Hb and lymphocyte count. The hematological profile of FDRs showed values between the controls and CD patients with ten FDRs that their parameters matched those of CD patients and significantly different from other FDRs. This group was defined as high-risk relatives (HRRs). Conclusions. Analysis of the hematological profile and CRP level might be proven as a fast, reliable, and less money-consuming tool to identify FDRs with a probable increased risk to develop the disease.

Correlation between cyclical epithelial barrier dysfunction and bacterial translocation in the relapses of intestinal inflammation

BACKGROUND

Although several factors have been implicated in the pathogenesis of inflammatory bowel disease (IBD), the mechanisms underlying the recurrent relapses have not yet been clarified. We hypothesized that epithelial barrier dysfunction, associated with intestinal motor disturbances, could play a key role in exacerbation of inflammatory illness due to an increased uptake of luminal antigen and bacterial translocation.

METHODS

Indomethacin administration to rats induced a long-lasting oscillation of active and quiescent phases of inflammation associated with phases of hypo and hypermotility. Rats selected at either active or quiescent phase and from 2 to 60 days after indomethacin treatment were used. Short-circuit current; conductance and HRP flux were evaluated in small intestinal segments mounted in Ussing Chambers. Enterocyte endosomes containing HRP and ultrastructural damage were assessed by electron microscopy. Bacterial translocation was determined by cultures from mesenteric lymph nodes.

RESULTS

Rats with induced enteritis in both phases demonstrated a long-lasting increase of epithelial paracellular permeability. In contrast, transcellular permeability was only disturbed during the active phases, coinciding with bacterial translocation and the increase in inflammatory parameters. Furthermore, although mithochondrial damage was observed throughout the inflammatory state, alterations were worse during the active phase.

CONCLUSIONS

The sustained enhancement of paracellular permeability could facilitate the constant passage of luminal antigens through the mucosa, and hence, be the basis for chronicity. By contrast, transcellular permeability only increases during the active phases, when hypomotility and bacterial translocation are also present, suggesting this factor may play a critical role in the course of acute relapses in IBD.

Protective effect of angelica sinensis polysaccharide on experimental immunological colon injury in rats

AIM: To study the effect of angelica sinensis polysaccharide (ASP) on immunological colon injury and its mechanisms in rats.

METHODS: Immunological colitis model of rats was induced by intracolon enema with 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) and ethanol. The experimental animals were randomly divided into normal control, model control, 5-aminosalicylic acid therapy groups and three doses of ASP therapy groups. The 6 groups were treated intracolonically with normal saline, normal saline, 5-aminosalicylic acid (100 mg·kg^-1), and ASP daily (8: 00 am) at the doses of 200, 400 and 800 mg·kg^-1 respectively for 21 days 7 d following induction of colitis. The rat colon mucosa damage index (CMDI), the histopathological score (HS), the score of occult blood test (OBT), and the colonic MPO activity were evaluated. The levels of SOD, MDA, NO, TNF-α, IL-2 and IL-10 in colonic tissues were detected biochemically and immunoradiometrically. The expressions of TGF-β and EGF in colonic tissues were also determined immunochemically.

RESULTS: Enhanced colonic mucosal injury, inflammatory response and oxidative stress were observed in colitis rats, which manifested as significant increases of CMDI, HS, OBT, MPO activity, MDA and NO contents, as well as the levels of TNF-α and IL-2 in colonic tissues, although colonic TGF-β protein expression, SOD activity and IL-10 content were significantly decreased compared with the normal control (P < 0.01). However, these parameters were found to be significantly ameliorated in colitis rats treated intracolicly with ASP at the doses of 400 and 800 mg·kg^-1 (P < 0.05-0.01). Meantime, colonic EGF protein expression in colitis rats was remarkably up-regulated.

CONCLUSION: ASP has a protective effect on immunological colon injury induced by TNBS and ethanol enema in rats, which was propably due to the mechanism of antioxidation, immunomodulation and promotion of wound repair.

Comparison of therapeutic efficacy between tumor-derived heat shock protein 70 and interleukine-2

AIM

To compare and analyze the therapeutic effect of tumor-derived heat shock protein 70 and globally accepted interleukin-2, to evaluate the anti-tumor capacity of HSP70, and to provide significant information for HSP70 administration to treat human cancers.

METHODS

Cell Culture, techniques for protein extraction and purification, SDS-PAGE, Western-blot and animal experiment were used in this study.

RESULTS

Both IL-2 and HSP70 showed therapeutic effect in tumor-bearing mice. The best effect was observed in 100 000 U IL-2 and 10 μg HSP70 administrations, and partial efficacy was found in 50000 U IL-2 and 5 μg HSP70 administrations. The effect of 100000 U IL-2 was nearly as good as that of 5 μg HSP70. About 40 % mice receiving HSP70 10 μg administration survived over 90 days, the average survival period of this group was over 56.8 days, whereas the control group was 17.3 days, IL-2 50 000 group, 26.3 days, IL-2 100 000 group, 36.6 days, and 5 μg HSP70 group, 27.7 days. Significant difference was found (P<0.05) when compared with the HSP70 10 μg group and control group.

CONCLUSION

HSP70 has a specific anti-tumor effect and obviously exceeded IL-2 .Those data provide significant information for the treatment of human cancers.

Relationship between overexpression of NK-1R, NK-2R and intestinal mucosal damage in acute necrotizing pancreatitis

AIM: To study the expression of neurokinin-1 receptor (NK-1R) and neurokinin-2 receptor (NK-2R) in distal ileum of acute necrotizing pancreatitis (ANP) and to evaluate the relationship between expression of these two receptors and intestinal mucosal damage.

METHODS: A total of 130 adult Sprague-Dawley rats were randomly divided into two groups: the rats in ANP group (n = 80) were induced by the retrograde intraductal infusion of 30 g·L^-1 sodium taurocholate. And the rats in normal control group (n = 50) received laparotomy only. Sacrifices were made 6 h, 12 h, 24 h and 48 h later in ANP and normal control group after induction respectively. Intestinal mucosal permeability was studied by intrajejunal injection of 1.5mCi radioactive isotope ^99mTc-diethlene triamine pentacetic acid (DTPA) and the radioactivity of ^99mTc-DTPA content in urine was measured 6 h, 12 h, 24 h and 48 h after induction. Then the pancreas and intestine were prepared for pathology. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the mRNA expression of NK-1R and NK-2R, and Western blot was used to investigate the protein level of NK-1R and NK-2R.

RESULTS: In ANP rats, serious histologic damages in intestinal mucosa were observed, and the radioactivity of ^99mTc-DTPA in urine increased significantly in the ANP group. RT-PCR revealed that NK-1R and NK-2R mRNA level was overexpressed in the distal ileum of ANP as compared with the normal control group. Western blot discovered stronger NK-1R (14-fold increase) and NK-2R (9-fold increase) immunoreactivity in the intestinal mucosa of ANP rats. Moreover, the overexpression of NK-1R was associated with mucosal pathological score (r = 0.77, P < 0.01) and intestinal permeability (r = 0.68, P < 0.01) in ANP rats.

CONCLUSION: NK-1R and NK-2R contribute to disrupted neuropeptides loop balance, deteriorate intestinal damage, and are involved in pathophysiological changes in ANP.

Elevated basal intestinal mucosal cytokine levels in asymptomatic first-degree relatives of patients with Crohn’s disease

AIM: To determine levels of cytokines in colonic mucosa of asymptomatic first degree relatives of Crohn’s disease patients.

METHODS: Cytokines (Interleukin (IL) 1-Beta, IL-2, IL-6 and IL-8) were measured using ELISA in biopsy samples of normal looking colonic mucosa of first degree relatives of Crohn’s disease patients (n = 9) and fro m normal controls (n = 10) with no family history of Crohn’s disease.

RESULTS: Asymptomatic first degree relatives of patients with Crohn’s disease had significantly higher levels of basal intestinal mucosal cytokines (IL-2, IL-6 and IL-8) than normal controls. Whether these increase d cytokine levels serve as phenotypic markers for a genetic predisposition to de veloping Crohn’s disease later on, or whether they indicate early (pre-cli nical) damage has yet to be further defined.

CONCLUSION: Asymptomatic first degree relatives of Crohn’s disease patients have higher levels of cytokines in their normal-looking intestinal mucosa compared to normal controls. This supports the hypothesis that increased cytokines may be a cause or an early event in the inflammatory cascade of Crohn’s disease and are not merely a result of the inflammatory process.