Cellular and molecular mechanisms of intestinal fibrosis

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.

Combination of corticosteroids and 5-aminosalicylates or corticosteroids alone for patients with moderate-severe active ulcerative colitis:A global survey of physicians'practice

AIM To examine treatment decisions of gastroenterologists regarding the choice of prescribing 5-aminosalycilates(5ASA) with corticosteroids(CS) versus corticosteroids alone for patients with active ulcerative colitis(UC). METHODS A cross-sectional questionnaire exploring physicians' attitude toward 5ASA + CS combination therapy vs CS alone was developed and validated. The questionnaire was distributed to gastroenterology experts in twelve countries in five continents. Respondents' agreement with stated treatment choices were assessed by standardized Likert scale. Background professional characteristics of respondents were analyzed for correlation with responses. RESULTS Six hundred and sixty-four questionnaires were distributed and 349 received(52.6% response rate). Of 340 eligible respondents, 221(65%) would continue 5ASA in a patient hospitalized for intravenous CS treatment due to a moderate-severe UC flare, while 108(32%) would stop the 5ASA(P < 0.001), and 11(3%) are undecided. Similarly, 62% would continue 5ASA in an out-patient starting oral CS. However, only 140/340(41%) would proactively start 5ASA in a hospitalized patient not receiving 5ASA before admission. Most(94%) physicians consider the safety profile of 5ASA as very good. Only 52% consider them inexpensive, 35% perceive them to be expensive and 12% are undecided. On multi-variable analysis, less years of practice and perception of a plausible additive mechanistic effect of 5ASA + CS were positively associated with the decision to continue 5ASA with CS. CONCLUSION Despite the absence of data supporting its benefit, most gastroenterologists endorse combination of 5ASA + CS for patients with active moderate-to-severe UC. Randomized controlled trials are needed to assess if 5ASA confer any benefit for these patients.

Diagnostic delay in inflammatory bowel diseases in a German population

BACKGROUND Early diagnosis is key to prevent bowel damage in inflammatory bowel disease(IBD).Risk factor analyses linked with delayed diagnosis in European IBD patients are scarce and no data in German IBD patients exists.AIM To identify risk factors leading to prolonged diagnostic time in a German IBD cohort.METHODS Between 2012 and 2022,430 IBD patients from four Berlin hospitals were enrolled in a prospective study and asked to complete a 16-item questionnaire to determine features of the path leading to IBD diagnosis.Total diagnostic time was defined as the time from symptom onset to consulting a physician(patient waiting time)and from first consultation to IBD diagnosis(physician diagnostic time).Univariate and multivariate analyses were performed to identify risk factors for each time period.RESULTS The total diagnostic time was significantly longer in Crohn’s disease(CD)compared to ulcerative colitis(UC)patients(12.0 vs 4.0 mo;P<0.001),mainly due to increased physician diagnostic time(5.5 vs 1.0 mo;P<0.001).In a multivariate analysis,the predominant symptoms diarrhea(P=0.012)and skin lesions(P=0.028)as well as performed gastroscopy(P=0.042)were associated with longer physician diagnostic time in CD patients.In UC,fever was correlated(P=0.020)with shorter physician diagnostic time,while fatigue(P=0.011)and positive family history(P=0.046)were correlated with longer physician diagnostic time.CONCLUSION We demonstrated that CD patients compared to UC are at risk of long diagnostic delay.Future efforts should focus on shortening the diagnostic delay for a better outcome in these patients.

Fibrogenesis in inflammatory bowel disease——A bright road ahead

Intestinal fibrosis is a frequent complication of inflammatory bowel diseases (IBD),and can lead to stricture formation and intestinal obstruction. Clinically apparent stenosis occurs in more than 30% of patients with Crohn's disease (CD) and about 5%~10% of patients with ulcerative colitis (UC) [l -2],and its management represents an important and frequent challenge in clinical practice. Despite its tremendous clinical impact the tools we currently have to address this challenge are limited (l)Anti-inflammatory therapies are only a temporizing measure to relieve obstruction and re-obstruction is frequent, necessitating endoscopic balloon dilation or surgical intervention(3 5)No specific anti-fibrotic therapy exists at present, and therefore it is critical to understand the mechanisms of intestinal fibrogenesis to develop targeted therapeutic approaches.