AIM： To investigate whether microproteinuria in patients with inflammatory bowel disease （IBD） is associated with the disease activity or the treatment with 5-aminosalicylic acid （5-ASA）. METHODS： We prospective...AIM： To investigate whether microproteinuria in patients with inflammatory bowel disease （IBD） is associated with the disease activity or the treatment with 5-aminosalicylic acid （5-ASA）. METHODS： We prospectively studied microproteinuria in 86 consecutive patients with IBD, 61 with ulcerative colitis （UC） and 25 with Crohn＇s disease （CD）, before as well as 2 and 6 months after their inclusion in the study. Forty-six patients received 5-ASA for a period of 28.8 months （range 1-168 too）. Microalbuminuria （mALB） and urine levels of the renal tubular proteins β2-microglobulin （β2mGLB） and β-N-acetyI-D-glucosamidase （β-NAG） as well as the creatinine clearance were determined in a 12-h overnight urine collection. Tumor necrosis factor-α （TNF-α） serum levels were also measured. RESULTS： A total of 277 measurements （194 in UC patients and 83 in CD patients） were performed. The prevalence of abnormal microoproteinuria in UC and CD patients was 12.9% and 6.0% for mALB, 22.7% and 27.7% for B2mGLB, and 11.3% and 8.4% for β-NAG, respectively, mALB was not associated with IBD activity. β2mGLB and B-NAG urine levels were correlated to UC activity （UCAI： P〈0.01; UCEI： P〈0.005）. mALB in UC patients and β-NAG urine levels in CD patients were related to TNF-α serum levels. An association was noticed between microproteinuria and smoking habit. Treatment with 5-ASA was not correlated to the severity of microproteinuria or to the changes of creatinine clearance.CONCLUSION： Microproteinuria is mainly associated with UC and its activity but not affected by 5-ASA.展开更多
Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by chronic relapsing intestinal inflammation. It has been a worldwide health-care problem with a continually inc...Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by chronic relapsing intestinal inflammation. It has been a worldwide health-care problem with a continually increasing incidence. It is thought that IBD results from an aberrant and continuing immune response to the microbes in the gut, catalyzed by the genetic susceptibility of the individual. Although the etiology of IBD remains largely unknown, it involves a complex interaction between the genetic, environmental or microbial factors and the immune responses. Of the four components of IBD pathogenesis, most rapid progress has been made in the genetic study of gut inflammation. The latest internationally collaborative studies have ascertained 163 susceptibility gene loci for IBD. The genes implicated in childhood-onset and adult-onset IBD overlap, suggesting similar genetic predispositions. However, the fact that genetic factors account for only a portion of overall disease variance indicates that microbial and environmental factors may interact with genetic elements in the pathogenesis of IBD. Meanwhile, the adaptive immune response has been classically considered to play a major role in the pathogenesis of IBD, as new studies in immunology and genetics have clarified that the innate immune response maintains the same importance in inducing gut inflammation. Recent progress in understanding IBD pathogenesis sheds lights on relevant disease mechanisms, including the innate and adaptive immunity, and the interactions between genetic factors and microbial and environmental cues. In this review, we provide an update on the major advances that have occurred in above areas. (C) 2014 Baishideng Publishing Group Co., Limited. All rights reserved.展开更多
Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), rep- resents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with...Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), rep- resents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal mac- rophages play an important role in the mucosal im- mune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major con- tributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cyto- kine therapies have been developed and tested for the treatment of IBD patients.展开更多
Theories explaining the etiopathogenesis of inflammatory bowel disease （IBD） have been proposed ever since Crohn＇s disease （CD） and ulcerative colitis （UC） were recognized as the two major forms of the disease....Theories explaining the etiopathogenesis of inflammatory bowel disease （IBD） have been proposed ever since Crohn＇s disease （CD） and ulcerative colitis （UC） were recognized as the two major forms of the disease. Although the exact cause（s） and mechanisms of tissue damage in CD and UC have yet to be completely understood, enough progress has occurred to accept the following hypothesis as valid： IBD is an inappropriate immune response that occurs in genetically susceptible individuals as the result of a complex interaction among environmental factors, microbial factors, and the intestinal immune system. Among an almost endless list of environmental factors, smoking has been identified as a risk factor for CD and a protective factor for UC. Among microbial factors, no convincing evidence indicates that classical infectious agents cause IBD, while mounting evidence points to an abnormal immune response against the normal enteric flora as being of central importance. Gut inflammation is mediated by cells of the innate as well as adaptive immune systems, with the additional contribution of non-immune cells, such as epithelial, mesenchymal and endothelial cells, and platelets.展开更多
Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important ro...Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important roles in the development of IBD either by causing inflammation directly or indirectly through an altered immune system. New technologies have allowed researchers to be able to quantify the various components of the microbiome, which will allow for future developments in the etiology of IBD. Various components of the mucosal immune system are implicated in the pathogenesis of IBD and include intestinal epithelial cells, innate lymphoid cells, cells of the innate (macrophages/monocytes, neutrophils, and dendritic cells) and adaptive (T-cells and B-cells) immune system, and their secreted mediators (cytokines and chemokines). Either a mucosal susceptibility or defect in sampling of gut luminal antigen, possibly through the process of autophagy, leads to activation of innate immune response that may be mediated by enhanced toll-like receptor activity. The antigen presenting cells then mediate the differentiation of naïve T-cells into effector T helper (Th) cells, including Th1, Th2, and Th17, which alter gut homeostasis and lead to IBD. In this review, the effects of these components in the immunopathogenesis of IBD will be discussed.展开更多
Inflammatory bowel disease (IBD) is traditionally con- sidered to be common in the Western world, and its incidence has sharply increased since the early 1950s. In contrast, until the last decade, low prevalence and i...Inflammatory bowel disease (IBD) is traditionally con- sidered to be common in the Western world, and its incidence has sharply increased since the early 1950s. In contrast, until the last decade, low prevalence and incidence rates have been reported from other parts of the world including Eastern Europe, South America, Asia and the Pacific region. Recent trends indicate a change in the epidemiology of IBD with previously low incidence areas now reporting a progressive rise in the incidence, while in West European and North American countries the figures have stabilized or slightly increased, with decreasing incidence rates for ulcerative colitis. Some of these changes may represent differences in diagnostic practices and increasing awareness of the disease. The quality of studies is also variable. Additional epidemio- logic studies are needed to better define the burden of illness, explore the mechanism of association with envi- ronmental factors, and identify new risk factors.展开更多
Underweight and specific nutrient deficiencies are frequent in adult patients with inflammatory bowel disease(IBD).In addition,a significant number of children with IBD,especially Crohn's disease(CD) have impaired...Underweight and specific nutrient deficiencies are frequent in adult patients with inflammatory bowel disease(IBD).In addition,a significant number of children with IBD,especially Crohn's disease(CD) have impaired linear growth.Nutrition has an important role in the management of IBD.In adults with CD,enteral nutrition(EN) is effective in inducing clinical remission of IBD,although it is less efficient than corticosteroids.Exclusive EN is an established primary therapy for pediatric CD.Limited data suggests that EN is as efficient as corticosteroids for induction of remission.Additional advantages of nutritional therapy are control of inflammation,mucosal healing,positive benefits to growth and overall nutritional status with minimal adverse effects.The available evidence suggests that supplementary EN may be effective also for maintenance of remission in CD.More studies are needed to confirm these findings.However,EN supplementation could be considered as an alternative or as an adjunct to maintenance drug therapy in CD.EN does not have a primary therapeutic role in ulcerative colitis.Specific compositions of enteral dietselemental diets or diets containing specific components-were not shown to have any advantage over standard polymeric diets and their place in the treatment of CD or UC need further evaluation.Recent theories suggest that diet may be implicated in the etiology of IBD,however there are no proven dietary approaches to reduce the risk of developing IBD.展开更多
The etiopathology of inflammatory bowel disease （IBD） remains elusive. Accumulating evidence suggests that the abnormality of innate and adaptive immunity responses plays an important role in intestinal inflam- mati...The etiopathology of inflammatory bowel disease （IBD） remains elusive. Accumulating evidence suggests that the abnormality of innate and adaptive immunity responses plays an important role in intestinal inflam- mation. IBD including Crohn＇s disease （CD） and ulcerative colitis （UC） is a chronic inflammatory disease of the gastrointestinal tract, which is implicated in an inappropriate and overactive mucosal immune response to luminal flora. Traditionally, CD is regarded as a Thl- mediated inflammatory disorder while UC is regarded as a Th2-1ike disease. Recently, Th17 cells were identified as a new subset of T helper cells unrelated to Thl or Th2 cells, and several cytokines [e.g. interleukin （IL）-21, IL-23] are involved in regulating their activation and differentiation. They not only play an important role in host defense against extracellular pathogens, but are also associated with the development of autoimmunity and inflammatory response such as IBD. The identification of Th17 cells helps us to explain some of the anomalies seen in the Thl/Th2 axis and has broadened our understanding of the immunopathological effects of Th17 cells in the development of IBD.展开更多
A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms. In this review, we provide an overview about the major ...A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms. In this review, we provide an overview about the major components of this protective system as for example an intact epithelium, the synthesis of various antimicrobial peptides (AMPs) and the formation of the mucus layer. We highlight the crucial importance of their correct functioning for the maintenance of a proper intestinal function and the prevention of dysbiosis and disease. Barrier disturbances including a defective production of AMPs, alterations in thickness or composition of the intestinal mucus layer, alterations of pattern-recognition receptors, defects in the process of autophagy as well as unresolved endoplasmic reticulum stress result in an inadequate host protection and are thought to play a crucial role in the pathogenesis of the inflammatory bowel diseases Crohn’s disease and ulcerative colitis.展开更多
Inflammatory bowel disease （IBD） includes two similar yet distinct conditions called ulcerative colitis （UC） and Crohn＇s disease （CD）. These diseases affect the digestive system and cause the inflammation of in...Inflammatory bowel disease （IBD） includes two similar yet distinct conditions called ulcerative colitis （UC） and Crohn＇s disease （CD）. These diseases affect the digestive system and cause the inflammation of intestinal tissue, form sores and bleed easily. Most children with IBD are diagnosed in late childhood and adolescence. However, both UC and CD have been reported as early as in infancy. Most information pertaining to the epidemiology of IBD is based upon adult studies. Symptoms include abdominal pain, cramping, fatigue and diarrhea. Genetic factors play a significant role in determining IBD susceptibility. Epidemiological data support a genetic contribution to the pathogenesis of IBD. Recently, numerous new genes have been identified as being involved in the genetic susceptibility to IBD： TNF- 308A, CARD15 （NOD2）, MIF-173, N-acetyltransferase 2 （NAT2）, NKG2D （natural killer cell 2D）, STAT6 （signal transducer and activator of transcription 6）, CTLA-4 （cytotoxic T lymphocyte antigen-4）, MICA-MICB （major histocompatibility complex A and B）, HLA-DRB1, HLA class-Ⅱ, IL-18, IL-4, MICA-A5, CD14, TI R4, Fas-670, p53 and NF-kB. The characterization of these novel genes has the potential to identify therapeutic agents and aid clinical assessment of phenotype and prognosis in patients with IBD （UC and CD）.展开更多
Helicobacter pylori(H.pylori)infection is one of the most widely spread infectious diseases in humans.It can cause chronic gastritis,peptic ulcer disease and gastric malignancies and has been associated with extra-gas...Helicobacter pylori(H.pylori)infection is one of the most widely spread infectious diseases in humans.It can cause chronic gastritis,peptic ulcer disease and gastric malignancies and has been associated with extra-gastric disorders.H.pylori elicit a chronic systemic inflammatory response which,under certain conditions,may trigger autoimmune reactions and may be implicated in the pathogenesis of autoimmune diseases.Although the pathogenesis of inflammatory bowel disease(IBD)is unknown,it is thought to result from complex interactions between environmental factors and microbiota in the gut of individuals who are genetically susceptible.Several bacterial and viral agents have been implicated in the aetiology of IBD.In theory,H.pylori infection could be involved in the pathogenesis of IBD by inducing alterations in gastric and/or intestinal permeability or by causing immunological derangements resulting in absorption of antigenic material and autoimmunity via various immunological pathways.Similar mechanisms may also be responsible for the co-existence of IBD with other autoimmune diseases and/or extra-intestinal manifestations.However,the epidemiological data fail to support this association.Infact,various studies indicate that the prevalence of H.pylori infection is low in patients with IBD,suggesting a protective role for this infection in the development of IBD.In this report,we aim to shed light on proposed mechanisms and confounding factors underlying the potential link between H.pylori infection and IBD.展开更多
Vitamin D deficiency is commonly diagnosed among patients with inflammatory bowel disease (IBD). Patients with IBD are at risk of low bone density and increased fractures due to low vitamin D levels, long standing dis...Vitamin D deficiency is commonly diagnosed among patients with inflammatory bowel disease (IBD). Patients with IBD are at risk of low bone density and increased fractures due to low vitamin D levels, long standing disease, and frequent steroid exposures; as a result, it is well established that vitamin D supplementation in this population is important. There is increasing support for the role of vitamin D in strengthening the innate immune system by acting as an immunomodulator and reducing inflammation in experimental and human IBD. The active form of vitamin D, 1,25(OH)D3, acts on T cells to promote T helper (Th)2/regulatory T responses over Th1/Th17 responses; suppresses dendritic cell inflammatory activity; induces antibacterial activity; and regulates cytokine production in favor of an anti-inflammatory response. Murine and human IBD studies support a therapeutic role of vitamin D in IBD. Risk factors for vitamin D deficiency in this population include decreased sunlight exposure, disease duration, smoking, and genetics. Vitamin D normalization is associated with reduced risk of relapse, reduced risk of IBD-related surgeries, and improvement in quality of life. Vitamin D is an inexpensive supplement which has been shown to improve IBD outcomes. However, further research is required to determine optimal serum vitamin D levels which will achieve beneficial immune effects, and stronger evidence is needed to support the role of vitamin D in inducing disease response and remission, as well as maintaining this improvement in patients’ disease states.展开更多
AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochr...AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochrane Library databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines(period: 1985-2018) to identify studies reporting population-based data on the incidence of pediatriconset(< 19 years at diagnosis) IBD in full manuscripts. Two authors carried out screening and data extraction. Choropleth interactive maps and temporal trends were used to illustrate the international differences and incidences of and changes in IBD and subtypes.RESULTS In total, one hundred forty studies reporting data from 38 countries were considered in this review. The highest annual pediatric incidences of IBD were 23/100000 person-years in Europe, 15.2/100000 in North America, and 11.4/100000 in Asia/the Middle East and Oceania. The highest annual incidences of Crohn's disease(CD) were 13.9/100000 in North America and 12.3/100000 in Europe. The highest annual incidences of ulcerative colitis(UC) were 15.0/100000 in Europe and 10.6/100000 in North America. The highest annual incidences of IBD-unclassified(IBD-U) were 3.6/100000 in Europe and 2.1/100000 in North America. In the time-trend analyses, 67% of CD, 46% of UC and 11% of IBD-U studies reported an increasing incidence(P < 0.05). The risk of IBD is increasing among firstgeneration of migrant populations.CONCLUSION Globally, the incidence of IBD varies greatly by geographical areas. The steadily increasing incidence of pediatric IBD over time indicates its emergence as a global disease, suggesting that studies should investigate the environmental risk factors among pediatric cohorts.展开更多
The pool of microbes inhabiting our body is known as “microbiota” and their collective genomes as “microbiome”. The colon is the most densely populated organ in the huma...The pool of microbes inhabiting our body is known as “microbiota” and their collective genomes as “microbiome”. The colon is the most densely populated organ in the human body, although other parts, such as the skin, vaginal mucosa, or respiratory tract, also harbour specific microbiota. This microbial community regulates some important metabolic and physiological functions of the host, and drives the maturation of the immune system in early life, contributing to its homeostasis during life. Alterations of the intestinal microbiota can occur by changes in composition (dysbiosis), function, or microbiota-host interactions and they can be directly correlated with several diseases. The only disease in which a clear causal role of a dysbiotic microbiota has been demonstrated is the case of Clostridium difficile infections. Nonetheless, alterations in composition and function of the microbiota have been associated with several gastrointestinal diseases (inflammatory bowel disease, colorectal cancer, or irritable bowel syndrome), as well as extra-intestinal pathologies, such as those affecting the liver, or the respiratory tract (e.g., allergy, bronchial asthma, and cystic fibrosis), among others. Species of Bifidobacterium genus are the normal inhabitants of a healthy human gut and alterations in number and composition of their populations is one of the most frequent features present in these diseases. The use of probiotics, including bifidobacteria strains, in preventive medicine to maintain a healthy intestinal function is well documented. Probiotics are also proposed as therapeutic agents for gastrointestinal disorders and other pathologies. The World Gastroenterology Organization recently published potential clinical applications for several probiotic formulations, in which species of lactobacilli are predominant. This review is focused on probiotic preparations containing Bifidobacterium strains, alone or in combination with other bacteria, which have been tested in human clinical 展开更多
Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosom...Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosomal instability, microsatellite instability, and hypermethylation, also play a role in colitis-associated colon carcinogenesis. Colon cancer risk in inflammatory bowel disease increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and degree of inflammation of the bowel. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid and statins. To reduce CRC mortality in IBD, colonoscopic surveillance with random biopsies remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Patients with small intestinal Crohn’s disease are at increased risk of small bowel adenocarcinoma. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal- anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. Other extra intestinal cancers, such as hepatobiliary and hematopoietic cancer, have shown variable incidence rates. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.展开更多
Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in s...Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelialand endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic proc-ess, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.展开更多
文摘AIM： To investigate whether microproteinuria in patients with inflammatory bowel disease （IBD） is associated with the disease activity or the treatment with 5-aminosalicylic acid （5-ASA）. METHODS： We prospectively studied microproteinuria in 86 consecutive patients with IBD, 61 with ulcerative colitis （UC） and 25 with Crohn＇s disease （CD）, before as well as 2 and 6 months after their inclusion in the study. Forty-six patients received 5-ASA for a period of 28.8 months （range 1-168 too）. Microalbuminuria （mALB） and urine levels of the renal tubular proteins β2-microglobulin （β2mGLB） and β-N-acetyI-D-glucosamidase （β-NAG） as well as the creatinine clearance were determined in a 12-h overnight urine collection. Tumor necrosis factor-α （TNF-α） serum levels were also measured. RESULTS： A total of 277 measurements （194 in UC patients and 83 in CD patients） were performed. The prevalence of abnormal microoproteinuria in UC and CD patients was 12.9% and 6.0% for mALB, 22.7% and 27.7% for B2mGLB, and 11.3% and 8.4% for β-NAG, respectively, mALB was not associated with IBD activity. β2mGLB and B-NAG urine levels were correlated to UC activity （UCAI： P〈0.01; UCEI： P〈0.005）. mALB in UC patients and β-NAG urine levels in CD patients were related to TNF-α serum levels. An association was noticed between microproteinuria and smoking habit. Treatment with 5-ASA was not correlated to the severity of microproteinuria or to the changes of creatinine clearance.CONCLUSION： Microproteinuria is mainly associated with UC and its activity but not affected by 5-ASA.
基金Supported by Grants from the National Natural Science Foundation of China,No.81270477
文摘Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by chronic relapsing intestinal inflammation. It has been a worldwide health-care problem with a continually increasing incidence. It is thought that IBD results from an aberrant and continuing immune response to the microbes in the gut, catalyzed by the genetic susceptibility of the individual. Although the etiology of IBD remains largely unknown, it involves a complex interaction between the genetic, environmental or microbial factors and the immune responses. Of the four components of IBD pathogenesis, most rapid progress has been made in the genetic study of gut inflammation. The latest internationally collaborative studies have ascertained 163 susceptibility gene loci for IBD. The genes implicated in childhood-onset and adult-onset IBD overlap, suggesting similar genetic predispositions. However, the fact that genetic factors account for only a portion of overall disease variance indicates that microbial and environmental factors may interact with genetic elements in the pathogenesis of IBD. Meanwhile, the adaptive immune response has been classically considered to play a major role in the pathogenesis of IBD, as new studies in immunology and genetics have clarified that the innate immune response maintains the same importance in inducing gut inflammation. Recent progress in understanding IBD pathogenesis sheds lights on relevant disease mechanisms, including the innate and adaptive immunity, and the interactions between genetic factors and microbial and environmental cues. In this review, we provide an update on the major advances that have occurred in above areas. (C) 2014 Baishideng Publishing Group Co., Limited. All rights reserved.
文摘Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), rep- resents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal mac- rophages play an important role in the mucosal im- mune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major con- tributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cyto- kine therapies have been developed and tested for the treatment of IBD patients.
基金Supported by a grant from the Broad Medical Research Program toS.D
文摘Theories explaining the etiopathogenesis of inflammatory bowel disease （IBD） have been proposed ever since Crohn＇s disease （CD） and ulcerative colitis （UC） were recognized as the two major forms of the disease. Although the exact cause（s） and mechanisms of tissue damage in CD and UC have yet to be completely understood, enough progress has occurred to accept the following hypothesis as valid： IBD is an inappropriate immune response that occurs in genetically susceptible individuals as the result of a complex interaction among environmental factors, microbial factors, and the intestinal immune system. Among an almost endless list of environmental factors, smoking has been identified as a risk factor for CD and a protective factor for UC. Among microbial factors, no convincing evidence indicates that classical infectious agents cause IBD, while mounting evidence points to an abnormal immune response against the normal enteric flora as being of central importance. Gut inflammation is mediated by cells of the innate as well as adaptive immune systems, with the additional contribution of non-immune cells, such as epithelial, mesenchymal and endothelial cells, and platelets.
基金Supported by NIH KO8 DK093578CCFA Career Development Award 3467(DQS)F Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute
文摘Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important roles in the development of IBD either by causing inflammation directly or indirectly through an altered immune system. New technologies have allowed researchers to be able to quantify the various components of the microbiome, which will allow for future developments in the etiology of IBD. Various components of the mucosal immune system are implicated in the pathogenesis of IBD and include intestinal epithelial cells, innate lymphoid cells, cells of the innate (macrophages/monocytes, neutrophils, and dendritic cells) and adaptive (T-cells and B-cells) immune system, and their secreted mediators (cytokines and chemokines). Either a mucosal susceptibility or defect in sampling of gut luminal antigen, possibly through the process of autophagy, leads to activation of innate immune response that may be mediated by enhanced toll-like receptor activity. The antigen presenting cells then mediate the differentiation of naïve T-cells into effector T helper (Th) cells, including Th1, Th2, and Th17, which alter gut homeostasis and lead to IBD. In this review, the effects of these components in the immunopathogenesis of IBD will be discussed.
文摘Inflammatory bowel disease (IBD) is traditionally con- sidered to be common in the Western world, and its incidence has sharply increased since the early 1950s. In contrast, until the last decade, low prevalence and incidence rates have been reported from other parts of the world including Eastern Europe, South America, Asia and the Pacific region. Recent trends indicate a change in the epidemiology of IBD with previously low incidence areas now reporting a progressive rise in the incidence, while in West European and North American countries the figures have stabilized or slightly increased, with decreasing incidence rates for ulcerative colitis. Some of these changes may represent differences in diagnostic practices and increasing awareness of the disease. The quality of studies is also variable. Additional epidemio- logic studies are needed to better define the burden of illness, explore the mechanism of association with envi- ronmental factors, and identify new risk factors.
文摘Underweight and specific nutrient deficiencies are frequent in adult patients with inflammatory bowel disease(IBD).In addition,a significant number of children with IBD,especially Crohn's disease(CD) have impaired linear growth.Nutrition has an important role in the management of IBD.In adults with CD,enteral nutrition(EN) is effective in inducing clinical remission of IBD,although it is less efficient than corticosteroids.Exclusive EN is an established primary therapy for pediatric CD.Limited data suggests that EN is as efficient as corticosteroids for induction of remission.Additional advantages of nutritional therapy are control of inflammation,mucosal healing,positive benefits to growth and overall nutritional status with minimal adverse effects.The available evidence suggests that supplementary EN may be effective also for maintenance of remission in CD.More studies are needed to confirm these findings.However,EN supplementation could be considered as an alternative or as an adjunct to maintenance drug therapy in CD.EN does not have a primary therapeutic role in ulcerative colitis.Specific compositions of enteral dietselemental diets or diets containing specific components-were not shown to have any advantage over standard polymeric diets and their place in the treatment of CD or UC need further evaluation.Recent theories suggest that diet may be implicated in the etiology of IBD,however there are no proven dietary approaches to reduce the risk of developing IBD.
基金Supported by Grants From the National Natural Science Foundation of China,No.30770988 and No.30971358
文摘The etiopathology of inflammatory bowel disease （IBD） remains elusive. Accumulating evidence suggests that the abnormality of innate and adaptive immunity responses plays an important role in intestinal inflam- mation. IBD including Crohn＇s disease （CD） and ulcerative colitis （UC） is a chronic inflammatory disease of the gastrointestinal tract, which is implicated in an inappropriate and overactive mucosal immune response to luminal flora. Traditionally, CD is regarded as a Thl- mediated inflammatory disorder while UC is regarded as a Th2-1ike disease. Recently, Th17 cells were identified as a new subset of T helper cells unrelated to Thl or Th2 cells, and several cytokines [e.g. interleukin （IL）-21, IL-23] are involved in regulating their activation and differentiation. They not only play an important role in host defense against extracellular pathogens, but are also associated with the development of autoimmunity and inflammatory response such as IBD. The identification of Th17 cells helps us to explain some of the anomalies seen in the Thl/Th2 axis and has broadened our understanding of the immunopathological effects of Th17 cells in the development of IBD.
基金Supported by Robert Bosch Foundation,Stuttgart,Germany
文摘A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms. In this review, we provide an overview about the major components of this protective system as for example an intact epithelium, the synthesis of various antimicrobial peptides (AMPs) and the formation of the mucus layer. We highlight the crucial importance of their correct functioning for the maintenance of a proper intestinal function and the prevention of dysbiosis and disease. Barrier disturbances including a defective production of AMPs, alterations in thickness or composition of the intestinal mucus layer, alterations of pattern-recognition receptors, defects in the process of autophagy as well as unresolved endoplasmic reticulum stress result in an inadequate host protection and are thought to play a crucial role in the pathogenesis of the inflammatory bowel diseases Crohn’s disease and ulcerative colitis.
基金Supported by The Science Foundation of Health Bureau of Shaanxi Province,China,No.04D26
文摘Inflammatory bowel disease （IBD） includes two similar yet distinct conditions called ulcerative colitis （UC） and Crohn＇s disease （CD）. These diseases affect the digestive system and cause the inflammation of intestinal tissue, form sores and bleed easily. Most children with IBD are diagnosed in late childhood and adolescence. However, both UC and CD have been reported as early as in infancy. Most information pertaining to the epidemiology of IBD is based upon adult studies. Symptoms include abdominal pain, cramping, fatigue and diarrhea. Genetic factors play a significant role in determining IBD susceptibility. Epidemiological data support a genetic contribution to the pathogenesis of IBD. Recently, numerous new genes have been identified as being involved in the genetic susceptibility to IBD： TNF- 308A, CARD15 （NOD2）, MIF-173, N-acetyltransferase 2 （NAT2）, NKG2D （natural killer cell 2D）, STAT6 （signal transducer and activator of transcription 6）, CTLA-4 （cytotoxic T lymphocyte antigen-4）, MICA-MICB （major histocompatibility complex A and B）, HLA-DRB1, HLA class-Ⅱ, IL-18, IL-4, MICA-A5, CD14, TI R4, Fas-670, p53 and NF-kB. The characterization of these novel genes has the potential to identify therapeutic agents and aid clinical assessment of phenotype and prognosis in patients with IBD （UC and CD）.
文摘Helicobacter pylori(H.pylori)infection is one of the most widely spread infectious diseases in humans.It can cause chronic gastritis,peptic ulcer disease and gastric malignancies and has been associated with extra-gastric disorders.H.pylori elicit a chronic systemic inflammatory response which,under certain conditions,may trigger autoimmune reactions and may be implicated in the pathogenesis of autoimmune diseases.Although the pathogenesis of inflammatory bowel disease(IBD)is unknown,it is thought to result from complex interactions between environmental factors and microbiota in the gut of individuals who are genetically susceptible.Several bacterial and viral agents have been implicated in the aetiology of IBD.In theory,H.pylori infection could be involved in the pathogenesis of IBD by inducing alterations in gastric and/or intestinal permeability or by causing immunological derangements resulting in absorption of antigenic material and autoimmunity via various immunological pathways.Similar mechanisms may also be responsible for the co-existence of IBD with other autoimmune diseases and/or extra-intestinal manifestations.However,the epidemiological data fail to support this association.Infact,various studies indicate that the prevalence of H.pylori infection is low in patients with IBD,suggesting a protective role for this infection in the development of IBD.In this report,we aim to shed light on proposed mechanisms and confounding factors underlying the potential link between H.pylori infection and IBD.
基金Supported by A graduate studentship from the Center of Excellence for Gastrointestinal and Immunity Research(CEGIIR)and the Alberta Innovates-Health Solutions Inflammatory Bowel Disease Consortium to Reich KM
文摘Vitamin D deficiency is commonly diagnosed among patients with inflammatory bowel disease (IBD). Patients with IBD are at risk of low bone density and increased fractures due to low vitamin D levels, long standing disease, and frequent steroid exposures; as a result, it is well established that vitamin D supplementation in this population is important. There is increasing support for the role of vitamin D in strengthening the innate immune system by acting as an immunomodulator and reducing inflammation in experimental and human IBD. The active form of vitamin D, 1,25(OH)D3, acts on T cells to promote T helper (Th)2/regulatory T responses over Th1/Th17 responses; suppresses dendritic cell inflammatory activity; induces antibacterial activity; and regulates cytokine production in favor of an anti-inflammatory response. Murine and human IBD studies support a therapeutic role of vitamin D in IBD. Risk factors for vitamin D deficiency in this population include decreased sunlight exposure, disease duration, smoking, and genetics. Vitamin D normalization is associated with reduced risk of relapse, reduced risk of IBD-related surgeries, and improvement in quality of life. Vitamin D is an inexpensive supplement which has been shown to improve IBD outcomes. However, further research is required to determine optimal serum vitamin D levels which will achieve beneficial immune effects, and stronger evidence is needed to support the role of vitamin D in inducing disease response and remission, as well as maintaining this improvement in patients’ disease states.
基金Supported by the“On Our Own Feet Movement-P?áteléstonozky”-Endowment Programand Research Project Progress Q-39
文摘AIM To perform a comprehensive review and provide an up-to-date synopsis of the incidence and trends of inflammatory bowel disease(IBD). METHODS We systematically searched the MEDLINE(source Pub Med), EMBASE and Cochrane Library databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines(period: 1985-2018) to identify studies reporting population-based data on the incidence of pediatriconset(< 19 years at diagnosis) IBD in full manuscripts. Two authors carried out screening and data extraction. Choropleth interactive maps and temporal trends were used to illustrate the international differences and incidences of and changes in IBD and subtypes.RESULTS In total, one hundred forty studies reporting data from 38 countries were considered in this review. The highest annual pediatric incidences of IBD were 23/100000 person-years in Europe, 15.2/100000 in North America, and 11.4/100000 in Asia/the Middle East and Oceania. The highest annual incidences of Crohn's disease(CD) were 13.9/100000 in North America and 12.3/100000 in Europe. The highest annual incidences of ulcerative colitis(UC) were 15.0/100000 in Europe and 10.6/100000 in North America. The highest annual incidences of IBD-unclassified(IBD-U) were 3.6/100000 in Europe and 2.1/100000 in North America. In the time-trend analyses, 67% of CD, 46% of UC and 11% of IBD-U studies reported an increasing incidence(P < 0.05). The risk of IBD is increasing among firstgeneration of migrant populations.CONCLUSION Globally, the incidence of IBD varies greatly by geographical areas. The steadily increasing incidence of pediatric IBD over time indicates its emergence as a global disease, suggesting that studies should investigate the environmental risk factors among pediatric cohorts.
基金Supported by The Spanish Ministry of Economy and Competitiveness and by FEDER European Union funds,projects No.AGL2010-14952,No.AGL2010-16525 and No.AGL2012-33278
文摘The pool of microbes inhabiting our body is known as “microbiota” and their collective genomes as “microbiome”. The colon is the most densely populated organ in the human body, although other parts, such as the skin, vaginal mucosa, or respiratory tract, also harbour specific microbiota. This microbial community regulates some important metabolic and physiological functions of the host, and drives the maturation of the immune system in early life, contributing to its homeostasis during life. Alterations of the intestinal microbiota can occur by changes in composition (dysbiosis), function, or microbiota-host interactions and they can be directly correlated with several diseases. The only disease in which a clear causal role of a dysbiotic microbiota has been demonstrated is the case of Clostridium difficile infections. Nonetheless, alterations in composition and function of the microbiota have been associated with several gastrointestinal diseases (inflammatory bowel disease, colorectal cancer, or irritable bowel syndrome), as well as extra-intestinal pathologies, such as those affecting the liver, or the respiratory tract (e.g., allergy, bronchial asthma, and cystic fibrosis), among others. Species of Bifidobacterium genus are the normal inhabitants of a healthy human gut and alterations in number and composition of their populations is one of the most frequent features present in these diseases. The use of probiotics, including bifidobacteria strains, in preventive medicine to maintain a healthy intestinal function is well documented. Probiotics are also proposed as therapeutic agents for gastrointestinal disorders and other pathologies. The World Gastroenterology Organization recently published potential clinical applications for several probiotic formulations, in which species of lactobacilli are predominant. This review is focused on probiotic preparations containing Bifidobacterium strains, alone or in combination with other bacteria, which have been tested in human clinical
文摘Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosomal instability, microsatellite instability, and hypermethylation, also play a role in colitis-associated colon carcinogenesis. Colon cancer risk in inflammatory bowel disease increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and degree of inflammation of the bowel. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid and statins. To reduce CRC mortality in IBD, colonoscopic surveillance with random biopsies remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Patients with small intestinal Crohn’s disease are at increased risk of small bowel adenocarcinoma. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal- anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. Other extra intestinal cancers, such as hepatobiliary and hematopoietic cancer, have shown variable incidence rates. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.
文摘Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelialand endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic proc-ess, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.
