Epithelial overexpression of interleukin-32alpha in inflammatory bowel disease

Interleukin (IL)-32 is a recently described proinflammatory cytokine, characterized by induction of nuclear factor (NF)-kappaB activation. We studied IL-32alpha expression in the inflamed mucosa of inflammatory bowel disease (IBD). We also investigated mechanisms regulating IL-32alpha expression. Tissue samples were obtained endoscopically or surgically from patients with ulcerative colitis (UC) (n = 10), Crohn's disease (CD) (n = 10), ischaemic colitis (n = 4) and normal colorectal tissues (n = 10). IL-32alpha expression was evaluated by standard immunohistochemical procedure. IL-32 mRNA expression was analysed by Northern blot. IL-32alpha was expressed weakly by colonic epithelial cells from normal individuals and subjects with ischaemic colitis. In the inflamed mucosa of IBD patients, epithelial IL-32alpha expression was increased markedly. In UC and CD patients, IL-32alpha expression was enhanced in affected mucosa compared to non-affected mucosa. In intestinal epithelial cell lines, expression of IL-32alpha mRNA and protein was enhanced by IL-1beta, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha. A combination of TNF-alpha plus IFN-gamma exerted synergistic effects. IL-32alpha induction by IL-1beta and/or TNF-alpha was mediated by NF-kappaB activation. Epithelial IL-32alpha expression was increased in IBD patients, and in CD patients in particular. IL-32alpha might be involved in the pathophysiology of IBD as a proinflammatory cytokine and a mediator of innate immune response.     

Management of inflammatory bowel disease with infliximab and other anti-tumor necrosis factor alpha therapies

Inflammatory bowel disease (IBD), most commonly referring to Crohn's disease and ulcerative colitis, is a chronic and disabling condition with an increasing incidence in southern Europe. The etiology of IBD remains unknown, but the characteristic disproportionate inflammatory response in the gut may develop through various mechanisms at the cellular and subcellular level. Tumor necrosis factor (TNF) alpha is one crucial mediator of this abnormal immune response, and in recent years, biological therapies targeting TNFα have significantly improved the management of IBD refractory to conventional therapies. Infliximab is the best studied anti-TNFα agent, and is currently approved in the European Union for adults and children with Crohn's disease and adults with ulcerative colitis; adalimumab is indicated for Crohn's disease in adults but not children, while certolizumab was not approved in the European Union for Crohn's disease. Infliximab has confirmed efficacy in adults with Crohn's disease (including fistulizing disease) and ulcerative colitis, with benefits observed in both clinical remission and mucosal healing, it is similarly effective in children with Crohn's disease. Evidence suggests that early treatment with infliximab may improve the natural course of the disease. Adalimumab showed efficacy in adults with Crohn's disease and more limited data suggest efficacy in children with Crohn's disease. Although certolizumab pegol has also shown promising data in adults with Crohn's disease, data in children are lacking. Anti-TNFα agents are generally well tolerated, although careful monitoring for adverse events such as infections, infusion reactions, lymphomas and demyelinating diseases is warranted. A definitive causal relationship between anti-TNFα agents and various adverse events is difficult to establish, as the underlying disease and concomitant immunosuppression also predispose patients to such events. Infliximab has not been associated with an increased incidence of serious events, and adalimumab and certolizumab are also generally well tolerated in clinical trials. Both adalimumab and certolizumab pegol are associated with lower levels of drug antibodies compared with infliximab. Reactivation of latent tuberculosis is a potential risk with any anti-TNFα agent, and identification and treatment is required before initiating therapy. Although causal relationships are difficult to establish, caution is advised with anti-TNFα compounds in patients developing neurological symptoms suggestive of demyelinating disease, or in those at high risk of malignancy. Infliximab is also generally well tolerated in children; however, data are scarce for the other compounds. No increased risks associated with pregnancy have been observed for infliximab or adalimumab, but caution in pregnancy and during breast-feeding is currently advocated. In terms of future research, more long-term data are needed for both certolizumab pegol in Crohn's disease and adalimumab in ulcerative colitis. More research on the benefits of early biological treatment on disease progression is needed. In summary, the anti-TNFα inhibitors represent a momentous advance in the treatment of Crohn's disease and ulcerative colitis refractory to conventional treatments. They offer significant benefits in quality of life and mucosal healing, and may have the potential to change the evolution of the disease when given early.     

Tumor necrosis factor family members and inflammatory bowel disease

Summary: Tumor necrosis factor (TNF) is one of the most potent effector cytokines in the pathogenesis of inflammatory bowel disease (IBD). Previous studies strongly implicate the critical involvement of several TNF family members in human IBD. This review focuses on the recent studies of TNF family members in IBD development. In particular, we discuss the findings about LIGHT (homologous to lymphotoxins, inducible expression, competes with herpes simplex virus glycoprotein D for herpes viral entry mediator, a receptor expressed on T lymphocytes) in the pathogenesis of IBD, and the potential mechanisms by which LIGHT induces IBD. Such mechanisms may also apply to other TNF family members.     

Hypoxia inducible factor-1alpha deficiency affects chondrogenesis of adipose-derived adult stromal cells

Increased cartilage-related disease, poor regeneration of cartilage tissue, and limited treatment options have led to intense research in tissue engineering of cartilage. Adipose-derived adult stromal cells (ADAS) are a promising cell source for skeletal tissue engineering; understanding ADAS cellular signaling and chondrogenesis will advance cell-based therapies in cartilage repair. Chondrocytes are unique-they are continuously challenged by a hypoxic microenvironment. Hypoxia inducible factor-1-alpha (HIF-1alpha), a critical mediator of a cell's response to hypoxia, plays a significant role in chondrocyte survival, growth arrest, and differentiation. By using an established in vitro 3-dimensional micromass system, we investigated the role of HIF-1alpha in chondrogenesis. Targeted deletion of HIF-1alpha in ADAS substantially inhibited the chondrogenic pathway specifically. In marked contrast, deletion of HIF-1alpha did not affect osteogenic differentiation but enhanced adipogenic differentiation. This study demonstrates the critical and specific interplay between HIF-1alpha and chondrogenesis in vitro.     

Hypoxia inducible factor‐1α‐induced interleukin‐33 expression in intestinal epithelia contributes to mucosal homeostasis in inflammatory bowel disease

Intestinal epithelial cells (IECs), an important barrier to gut microbiota, are subject to low oxygen tension, particularly during intestinal inflammation. Hypoxia inducible factor‐1α (HIF‐1α) is expressed highly in the inflamed mucosa of inflammatory bowel disease (IBD) and functions as a key regulator in maintenance of intestinal homeostasis. However, how IEC‐derived HIF‐1α regulates intestinal immune responses in IBD is still not understood completely. We report here that the expression of HIF‐1α and IL‐33 was increased significantly in the inflamed mucosa of IBD patients as well as mice with colitis induced by dextran sulphate sodium (DSS). The levels of interleukin (IL)?33 were correlated positively with that of HIF‐1α. A HIF‐1α‐interacting element was identified in the promoter region of IL‐33, indicating that HIF‐1α activity regulates IL‐33 expression. Furthermore, tumour necrosis factor (TNF) facilitated the HIF‐1α‐dependent IL‐33 expression in IEC. Our data thus demonstrate that HIF‐1α‐dependent IL‐33 in IEC functions as a regulatory cytokine in inflamed mucosa of IBD, thereby regulating the intestinal inflammation and maintaining mucosal homeostasis.     

Keratinocyte growth factor is highly overexpressed in inflammatory bowel disease.

Recently we demonstrated an important function of keratinocyte growth factor (KGF) in wound re-epithelialization. As KGF is mitogenic for various epithelial cells, we speculated about a role of KGF in epithelial repair processes of other organs as seen in a variety of inflammatory diseases. Here we demonstrate a strikingly increased expression of KGF in surgical specimens from patients suffering from Crohn's disease and ulcerative colitis. The levels of KGF expression strongly correlated with the degree of inflammation as assessed by histological analysis of adjacent tissue and expression analysis of the pro-inflammatory cytokine interleukin-1 beta. The highest levels of KGF mRNA and protein were found in mesenchymal cells of the lamina propria, particularly in highly inflamed areas. As the KGF receptor is expressed in intestinal epithelial cells, KGF seems to act in a paracrine manner to stimulate proliferation of these cells. These data suggest a crucial role of KGF in epithelial repair after injury caused by inflammatory processes.     

Interleukin-1 receptor antagonist VNTR-polymorphism in inflammatory bowel disease

Both genetic and environmental factors have been implicated in the etiology of inflammatory bowel diseases (IBD) i.e., Crohn's disease (CD) and ulcerative colitis (UC). Polymorphisms in cytokine genes are likely to influence an individual's predisposition to IBD. In intron 2 of the interleukin-1 receptor antagonist (IL-1ra) gene, a variable number of an 86-bp tandem repeat (VNTR) polymorphism leads to the existence of five different alleles. In order to analyze the association between certain IL-1ra VNTR-alleles and IBD, we investigated the IL-1ra genotype and allele frequencies in 342 unrelated IBD patients and in 401 healthy control individuals. CD patients were also genotyped for the three main associated variants in the NOD2/CARD15 gene. In the IBD group, a significant decrease in the frequency of IL-1ra allele 1 (P=0.048) compared to controls was observed. The frequency of IL-1ra genotype 1/1 was significantly lower in the IBD population vs the control group (P=0.018). Analysis of the CD population without NOD2 homozygotes and compound heterozygotes revealed a more significant decrease in IL-1ra genotype 1/1 compared to controls (P=0.038). These results support the hypothesis that the IL-1ra VNTR-polymorphism could be among the genetic factors that are of importance in IBD susceptibility.     

Neuroinflammation in inflammatory bowel disease

Inflammatory bowel disease is a chronic intestinal inflammatory condition, the pathology of which is incompletely understood. Gut inflammation causes significant changes in neurally controlled gut functions including cramping, abdominal pain, fecal urgency, and explosive diarrhea. These symptoms are caused, at least in part, by prolonged hyperexcitability of enteric neurons that can occur following the resolution of colitis. Mast, enterochromaffin and other immune cells are increased in the colonic mucosa in inflammatory bowel disease and signal the presence of inflammation to the enteric nervous system. Inflammatory mediators include 5-hydroxytryptamine and cytokines, as well as reactive oxygen species and the production of oxidative stress. This review will discuss the effects of inflammation on enteric neural activity and potential therapeutic strategies that target neuroinflammation in the enteric nervous system.     

Dysplasia in inflammatory bowel disease

The risk of neoplasia in ulcerative colitis and Crohns colitis increases with both the duration and the extent of disease. In patients with extensive or pancolitis, the cancer risk increases dramatically 8 to 10 years after the first onset of disease. Childhood onset of colitis and primary sclerosing cholangitis further increase the risk of developing colorectal carcinoma. The performance of surveillance endoscopy to identify dysplastic precursor lesions via endoscopic biopsy specimens has become the main management strategy to combat this risk. Biopsies should be classified as negative for dysplasia, indefinite for dysplasia, low-grade dysplasia, or high-grade dysplasia according to standard criteria. A prophylactic colectomy is the procedure of choice when high-grade dysplasia or low-grade dysplasia associated with a lesion or mass is present. Some centers also recommend a colectomy for the presence of low-grade dysplasia in flat mucosa. Given these management recommendations, care should be taken not to overcall reactive epithelial changes in the face of active colitis. All diagnoses of dysplasia should be confirmed, preferably by a pathologist experienced in interpreting gastrointestinal biopsies.     

激素性股骨头坏死过程中低氧诱导因子1α与骨细胞凋亡

背景：激素性股骨头缺血坏死发病机制未明,缺血缺氧是其根本原因,缺氧状态下低氧诱导因子1α参与多种信号通路传导。作者的前期研究发现,骨细胞凋亡与激素性股骨头缺血坏死存在关联。 目的：分析低氧诱导因子1α和骨细胞凋亡是否与激素性股骨头缺血坏死存在关联。 方法：选健康5月龄新西兰白兔20只,随机分为空白对照组和实验组,每组10只。实验组兔给予激素联合内毒素制备激素性股骨头缺血坏死模型。最后一次给药后第4周处死所有实验动物,取双侧后肢股骨头,光镜与电子显微镜下观察形态与超微结构变化,计算各组空缺骨陷窝;应用免疫组织化学技术检测低氧诱导因子1α表达,应用TUNEL法检测骨细胞凋亡。 结果与结论：实验组空缺骨陷窝率高于空白对照组(P < 0.01);实验组骨细胞凋亡高于空白对照组(P < 0.01);实验组低氧诱导因子1α低于空白对照组(P < 0.01);实验组中低氧诱导因子1α表达与细胞凋亡率呈负相关(r=-0.675),实验组中空缺骨陷窝率与细胞凋亡率呈正相关(r=0.793)。结果说明,在激素性股骨头缺血坏死早期,低氧诱导因子1α的低表达与骨细胞凋亡存在相关性,二者参与了激素性股骨头缺血坏死的病理变化过程,骨细胞的死亡方式为凋亡。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Probiotics and inflammatory bowel disease

Inflammatory bowel disease (IBD) is characterised by a chronic dysregulation of the inflammatory response in the gastrointestinal tract. While the pathogenesis is unclear, studies have demonstrated that the gastrointestinal tracts of patients with IBD are populated with increased levels of adherent and pathogenic bacteria. This evidence, combined with growing data accumulated from genetic studies as well as animal models of IBD, indicates that an aberrant response to altered enteric flora plays a significant role in the disease process. Current therapies for IBD have been directed towards the development of anti-inflammatory agents and immunomodulators to attenuate the inflammatory response in the gastrointestinal tract. Antibiotics are also partially effective in the treatment of IBD, presumably by altering the bowel flora. However, it is clear from clinical trials that immunomodulators and antibiotics are not effective in a large proportion of patients with IBD and other therapeutic alternatives need to be pursued. Probiotics are microbial supplements capable of recolonising the bowel with non-pathogenic strains of bacteria or yeast. Probiotics have long been shown to be beneficial in both infectious and non-infectious digestive disorders. Growing evidence indicates that probiotics may be effective in the treatment of specific clinical IBD conditions. This article addresses the current evidence for the role of enteric flora in the pathogenesis of IBD and the clinical evidence supporting the use of probiotics in specific clinical IBD conditions.     

Localization of TNF alpha in ileocolonic biopsies of patients with inflammatory bowel disease

BackgroundAlthough antitumor necrosis factor alfa (TNFα) agents are widely used to treat patients with inflammatory bowel diseases (IBD) - both Crohn's disease (CD) and ulcerative colitis (UC) - there is still some uncertainty in the cell type expressing TNFα in human ileo-colonic segments.AimsWe investigated the immunohistochemical (IHC) expression of TNFα in the ileo-colonic segments of patients with both active CD and UC, to establish its anatomic and cellular localization in the inflamed sites. Our aim was to identify patients potentially resistant to anti TNFα agents.Patients and methodsIleo-colonic slides of complete histological mapping of patients with CD and UC before any treatment was started were obtained, and serial sections assessed for TNFα expression, together with IHC markers for lymphocytes, macrophages, and plasma cells.ResultsTNFα was expressed in almost all inflamed segments of IBD patients, albeit with different strength, and was present, in addition to lymphocytes and, to a lesser extent, to macrophages, in plasma cells, where it had a strong positivity, as also demonstrated by colocalization of specific IHC staining. The expression of TNFα was mostly focal in CD patients and more diffuse in UC patients, likely due to the different patterns of inflammation (transmural and mucosal) of the two entities.ConclusionsIn IBD, TNFα is strongly expressed also in plasma cells, and it is easily evidenced by conventional IHC techniques. It remains to be established whether this observation might be useful in future to establish in routine biopsy samples whether patients may be responsive to treatments toward this cytokine.     

Precancer and cancer in inflammatory bowel disease

The risk of cancer in inflammatory bowel disease (IBD) is increased although it remains low. A clinical subgroup of patients with extensive or total ulcerative colitis and a history of symptoms for more than 10 yr is at greatest risk. In these patients biopsy evidence of epithelial dysplasia has successfully been used as a marker for increased cancer risk. A classification system for dysplasia has recently been devised, consisting of 3 categories: negative, indefinite and positive for dysplasia. The criteria for each category are discussed. For patients at high risk who decline prophylactic colectomy, a cancer surveillance programme involving periodic clinical assessment, sigmoidoscopy, colonoscopy and rectal and colonic biopsies has provided a reasonable alternative.     

Rheumatic manifestations in inflammatory bowel disease

Musculoskeletal symptoms (articular, periarticular and muscular involvement, osteoporosis and related fractures, and fibromyalgia) are the most common frequent extra-intestinal manifestations of inflammatory bowel disease (IBD) and affect 6–46% of patients. IBD-related arthropathy is one of a group of inflammatory arthritides known as seronegative spondyloarthropathies (SpA), which also includes idiopathic ankylosing spondylitis (AS), reactive arthritis, psoriatic arthritis, and undifferentiated SpA.The articular involvement in IBD significantly affects the patients’ quality of the life. Although magnetic resonance imaging (MRI) is still the gold standard for assessing entheseal involvement, ultrasonography (US) is a non-invasive and easily reproducible means of detecting early pathological changes in SpA patients. It can identify characteristic features of SpA such as enthesitis, bone erosions, synovitis, bursitis, and tenosynovitis and is therefore helpful for diagnostic purposes.Anti-TNF drugs should be used to treat AS patients with axial and peripheral symptoms (arthritis and enthesitis) who have persistently high levels of disease activity despite conventional treatment, and adalimumab and infliximab can also be beneficially used in patients with IBD.