Interleukin 10 promoter region polymorphisms in inflammatory bowel disease in Tunisian population

Biological, genetic and epigenetic markers in ulcerative colitis

In this review, we have summarized the existing knowledge of ulcerative colitis (UC) markers based on current literature, specifically, the roles of potential new biomarkers, such as circulating, fecal, genetic, and epigenetic alterations, in UC onset, disease activity, and in therapy response. UC is a complex multifactorial inflammatory disease. There are many invasive and non-invasive diagnostic methods in UC, including several laboratory markers which are employed in diagnosis and disease assessment; however, colonoscopy remains the most widely used method. Common laboratory abnormalities currently used in the clinical practice include inflammation-induced alterations, serum autoantibodies, and antibodies against bacterial antigens. Other new serum and fecal biomarkers are supportive in diagnosis and monitoring disease activity and therapy response; and potential salivary markers are currently being evaluated as well. Several UC-related genetic and epigenetic alterations are implied in its pathogenesis and therapeutic response. Moreover, the use of artificial intelligence in the integration of laboratory biomarkers and big data could potentially be useful in clinical translation and precision medicine in UC management.

Associations between CD24 gene polymorphisms and inflammatory bowel disease: A meta-analysis

AIM: To evaluate the relationships between CD24 gene polymorphisms and the risk of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD).

METHODS: The PubMed, Web of Science and Cochrane Library databases were searched (up to May 30, 2014). The search terms “CD24”, “inflammatory bowel disease”, “Crohn’s disease”, “Ulcerative colitis”, “IBD”, “CD” or “UC”; and “polymorphism”, “mutation” or “variant” were used. Association studies were limited to the English language, but no limitations in terms of race, ethnicity or geographic area were employed. Stata SE12 software was used to calculate the pooled odds ratios (ORs) with 95% confidence intervals (CIs). P < 0.05 was considered statistically significant. The information was independently extracted from each eligible study by two investigators. Two common polymorphisms, C170T (rs8734) and TG1527del (rs3838646), in the CD24 gene were assessed.

RESULTS: A total of three case-control studies including 2342 IBD patients and 1965 healthy controls were involved in this meta-analysis. The patients and controls were from Caucasian cohorts. The three articles included in this meta-analysis all conformed to Hardy-Weinberg equilibrium. This meta-analysis revealed that there were no significant associations between the two CD24 polymorphisms and the risk for IBD (all P > 0.05). However, in a disease subgroup analysis, we found that the CD24 C170T polymorphism was associated with an increased risk of UC in a dominant model (OR = 1.79, 95%CI: 1.15-2.77, P = 0.009) and an additive model (OR = 1.87, 95%CI: 1.19-2.93, P = 0.007), but this relationship was not present for CD. The CD24 TG1570del polymorphism was significantly associated with CD in the additive model (OR = 1.24, 95%CI: 1.01-1.52, P = 0.037).

CONCLUSION: Our findings provide evidence that the CD24 C170T polymorphism might contribute to the susceptibility to UC, and the CD24 TG1527del polymorphism might be associated with the risk of CD.

Pro- and anti-inflammatory cytokine gene single-nucleotide polymorphisms in inflammatory bowel disease

Anti-inflammatory cytokines have an important role in disease, tumour and transplant processes. Alterations in the regulation of several cytokines have been implicated in a variety of inflammatory disorders, including IBD (inflammatory bowel disease) [Crohn's disease (CD) and ulcerative colitis (UC)]. Cytokine polymorphisms are also known to affect the level of gene expression. Thus, the aim of this study was to determine the relationship between cytokine polymorphisms and the IBD pathologies in a Spanish population. Polymorphisms analysis was performed using PCR-SSOP using a microbeads luminex assay. The following polymorphisms were determined: TNFα [-238G/A (rs361525) and -308G/A (rs1800629)], IFNγ [+874A/T (rs62559044)], TGFβ [+869C/T (rs1982073) and +915G/C (rs1800471)], IL10 [-1082A/A (rs1800896), -592A/C (rs1800872), -819C/T (rs1800871)], IL6 [-174C/G (rs1800795)], IL12p40 [3'UTR -1188A/C (rs3212227)], IL1α [-889C/T (rs1800587)], IL1β [-511C/T (rs1143634) and +3962C/T (rs1143633)], IL1R [Pst-1 1970C/T] and IL1RA [Mspa-1 11100C/T]. No statistical differences in TNFα, IFNγ, TGFβ, IL10, IL6, IL1α, IL1β, IL1R and IL1Ra genotypes and allele distributions between the IBD groups and healthy controls were found. However, we observed significant differences in the 3'UTR -1188A/C polymorphism of IL12p40. So -1188A allele was increased in patients with UC and the -1188C allele (high IL12p40 production) was increased in patients with CD with respect to controls. These data are in concordance with the fact that CD has been shown to be associated with a Th1 T-cell-mediated inflammation model and high IL12/IFNγ production at histological affected sites. These data suggest that cytokine polymorphisms in TNFα, IFNγ, TGFβ, IL10, IL6 and IL1α, IL1β, IL1R and IL1Ra cytokine gene do not seem to be relevant in IBD susceptibility and IL12p40 3'UTR -1188A/C polymorphism seems to be associated with a differential IBD development.

Genetic update on inflammatory factors in ulcerative colitis: Review of the current literature

Ulcerative colitis (UC) is one of the main types of inflammatory bowel disease, which is caused by dysregulated immune responses in genetically predisposed individuals. Several genetic factors, including interleukin and interleukin receptor gene polymorphisms and other inflammation-related genes play central role in mediating and modulating the inflammation in the human body, thereby these can be the main cause of development of the disease. It is clear these data are very important for understanding the base of the disease, especially in terms of clinical utility and validity, but summarized literature is exiguous for challenge health specialist that can used in the clinical practice nowadays. This review summarizes the current literature on inflammation-related genetic polymorphisms which are associated with UC. We performed an electronic search of Pubmed Database among publications of the last 10 years, using the following medical subject heading terms: UC, ulcerative colitis, inflammation, genes, polymorphisms, and susceptibility.

Interleukin and interleukin receptor gene polymorphisms in inflammatory bowel diseases susceptibility

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), represents a group of chronic inflammatory disorders caused by dysregulated immune responses in genetically predisposed individuals. Genetic markers are associated with disease phenotype and long-term evolution, but their value in everyday clinical practice is limited at the moment. IBD has a clear immunological background and interleukins play key role in the process. Almost 130 original papers were revised including meta-analysis. It is clear these data are very important for understanding the base of the disease, especially in terms of clinical utility and validity, but text often do not available for the doctors use these in the clinical practice nowadays. We conducted a systematic review of the current literature on interleukin and interleukin receptor gene polymorphisms associated with IBD, performing an electronic search of PubMed Database from publications of the last 10 years, and used the following medical subject heading terms and/or text words: IBD, CD, UC, interleukins and polymorphisms.

Interleukin-10-1082A/G polymorphism and inflammatory bowel disease susceptibility: a meta-analysis based on 17,585 subjects

A large number of studies have shown that the interleukin-10 (IL-10)-1082A/G polymorphism is implicated in susceptibility to inflammatory bowel disease (IBD). However, the results are inconsistent. We performed this meta-analysis to estimate the association between -1082A/G polymorphism in the IL-10 gene and IBD susceptibility. A total number of 18 case-control studies including 17,585 subjects were identified. No association was found between -1082A/G polymorphism and ulcerative colitis (UC) susceptibility. However, increased risk of Crohn's disease (CD) was associated with -1082A/G polymorphism in the dominant genetic model (GG+GA vs. AA: OR=1.22, 95% CI: 1.02-1.46, P=0.028) and the heterozygote comparison (GA vs. AA: OR=1.28, 95% CI: 1.05-1.55, P=0.015). The results of this meta-analysis provide evidence for the association between IL-10-1082A/G polymorphism and susceptibility of CD. Due to several limitations in the present study, well-designed epidemiological studies with large sample size among different ethnicities should be performed in the future.

Macrophages from IBD patients exhibit defective tumour necrosis factor-α secretion but otherwise normal or augmented pro-inflammatory responses to infection

Defects in macrophage function have been implicated in the establishment of Crohn's disease (CD). However, the response of macrophages from CD patients to live bacteria, particularly Mycobacterium avium subsp. paratuberculosis (MAP), has not been addressed. Considering MAP has long been associated to CD, our objective was to assess whether macrophages from CD patients showed impaired inflammatory response to infection by MAP comparing to M. avium subsp. avium (MA) and other live intestinal commensal bacteria. Human peripheral blood monocyte-derived macrophages were obtained from CD patients, ulcerative colitis (UC) patients and controls. Following in vitro infection with MAP, MA, Escherichia coli or Enterococcus faecalis, cytokine levels and cell surface receptor expression were evaluated at different time points. Macrophages from CD patients showed impaired TNF-α secretion in response to bacterial challenge, but augmented IL-23 secretion and preserved IL-12 secretion and CD-40 expression. In addition, CD macrophages showed low IL-10 secretion. Macrophages from IBD patients showed increased expression of TLR-2 and -4, unaffected by infection. Differences in cytokine secretion observed after bacterial challenge were not MAP-specific, as other bacteria (E. coli and MA) showed similar effects. Macrophages from UC patients showed a less compromised TNF-α synthesis in response to mycobacterial infection than CD macrophages, with increased constitutive IL-12 secretion, and preserved IL-10 secretion. The increased IL-23 levels in response to infection and decreased IL-10 production observed in macrophages from CD patients may contribute to the inflammatory exacerbation observed in those patients.

A novel mouse model of inflammatory bowel disease links mammalian target of rapamycin-dependent hyperproliferation of colonic epithelium to inflammation-associated tumorigenesis

Inflammatory bowel disease (IBD) is a high-risk condition for human colorectal cancer. However, our mechanistic understanding of the link between inflammation and tumorigenesis in the colon is limited. Here we established a novel mouse model of colitis-associated cancer by genetically inactivating signal transducer and activator of transcription 3 (Stat3) in macrophages, with partial deletion in other myeloid and lymphoid cells. Inflammation developed in the colon of mutant mice spontaneously, and tumor lesions, including invasive carcinoma, arose in the inflamed region of the intestine with a frequency similar to that observed in human IBD patients. The development of both inflammation and tumors in the mutant mice required the presence of microflora. Indeed, inflammation was associated with disruption of colonic homeostasis, fulminant epithelial/tumor cell proliferation, and activation of the mammalian target of rapamycin (mTOR)-Stat3 pathway in epithelial and tumor cells. The activation of this pathway was essential for both the excess proliferation of epithelial/tumor cells and the disruption of colonic homeostasis in the mutant mice. Notably, a similar abnormal up-regulation of mTOR-Stat3 signaling was consistently observed in the colonic epithelial cells of human IBD patients with active disease. These studies demonstrate a novel mouse model of IBD-colorectal cancer progression in which disrupted immune regulation, mTOR-Stat3 signaling, and epithelial hyperproliferation are integrated and simultaneously linked to the development of malignancy.

A novel mouse model of inflammatory bowel disease links mammalian target of rapamycin-dependent hyperproliferation of colonic epithelium to inflammation-associated tumorigenesis

Inflammatory bowel disease (IBD) is a high-risk condition for human colorectal cancer. However, our mechanistic understanding of the link between inflammation and tumorigenesis in the colon is limited. Here we established a novel mouse model of colitis-associated cancer by genetically inactivating signal transducer and activator of transcription 3 (Stat3) in macrophages, with partial deletion in other myeloid and lymphoid cells. Inflammation developed in the colon of mutant mice spontaneously, and tumor lesions, including invasive carcinoma, arose in the inflamed region of the intestine with a frequency similar to that observed in human IBD patients. The development of both inflammation and tumors in the mutant mice required the presence of microflora. Indeed, inflammation was associated with disruption of colonic homeostasis, fulminant epithelial/tumor cell proliferation, and activation of the mammalian target of rapamycin (mTOR)-Stat3 pathway in epithelial and tumor cells. The activation of this pathway was essential for both the excess proliferation of epithelial/tumor cells and the disruption of colonic homeostasis in the mutant mice. Notably, a similar abnormal up-regulation of mTOR-Stat3 signaling was consistently observed in the colonic epithelial cells of human IBD patients with active disease. These studies demonstrate a novel mouse model of IBD-colorectal cancer progression in which disrupted immune regulation, mTOR-Stat3 signaling, and epithelial hyperproliferation are integrated and simultaneously linked to the development of malignancy.