Circulating tumour DNA and risk of recurrence in patients with asymptomatic versus symptomatic colorectal cancer.

BACKGROUND: Multiple initiatives aim to develop circulating tumour DNA (ctDNA) tests for early cancer detection in asymptomatic individuals. The few studies describing ctDNA-testing in both asymptomatic and symptomatic patients report lower ctDNA detection in the asymptomatic patients. Here, we explore if asymptomatic patients differ from symptomatic patients e.g. by including a 'low-ctDNA-shedding' and 'less-aggressive' subgroup. METHODS: ctDNA assessment was performed in two independent cohorts of consecutively recruited patients with asymptomatic colorectal cancer (CRC) (Cohort#1: n = 215, Cohort#2: n = 368) and symptomatic CRC (Cohort#1: n = 117, Cohort#2: n = 722). RESULTS: After adjusting for tumour stage and size, the odds of ctDNA detection was significantly lower in asymptomatic patients compared to symptomatic patients (Cohort#1: OR: 0.4, 95%CI: 0.2-0.8, Cohort#2: OR: 0.7, 95%CI: 0.5-0.9). Further, the recurrence risk was lower in asymptomatic patients (Cohort#1: sHR: 0.6, 95%CI: 0.3-1.2, Cohort#2: sHR: 0.6, 95%CI: 0.4-1.0). Notably, ctDNA-negative asymptomatic patients had the lowest recurrence risk compared to the symptomatic patients (Cohort#1: sHR: 0.2, 95%CI: 0.1-0.6, Cohort#2: sHR: 0.3, 95%CI: 0.2-0.6). CONCLUSIONS: Our study suggests that asymptomatic patients are enriched for a 'low-ctDNA-shedding-low-recurrence-risk' subgroup. Such insights are needed to guide ctDNA-based early-detection initiatives and should prompt discussions about de-escalation of therapy and follow-up for ctDNA-negative asymptomatic CRC patients.

Non-TGFß profibrotic signaling in ulcerative colitis after in vivo experimental intestinal injury in humans.

Although impaired regeneration is important in many gastrointestinal diseases including ulcerative colitis (UC), the dynamics of mucosal regeneration in humans are poorly investigated. We have developed a model to study these processes in vivo in humans. Epithelial restitution (ER) and extracellular matrix (ECM) regulation after an experimental injury of the sigmoid colonic mucosa was assessed by repeated high-resolution endoscopic imaging, histological assessment, RNA sequencing, deconvolution analysis, and 16S rDNA sequencing of the injury niche microbiome of 19 patients with UC in remission and 20 control subjects. Human ER had a 48-h lag before induction of regenerative epithelial cells [wound-associated epithelial (WAE) and transit amplifying (TA) cells] along with the increase of fibroblast-derived stem cell growth factor gremlin 1 mRNA (GREM1). However, UC deconvolution data showed rapid induction of inflammatory fibroblasts and upregulation of major structural ECM collagen mRNAs along with tissue inhibitor of metalloproteinase 1 (TIMP1), suggesting increased profibrotic ECM deposition. No change was seen in transforming growth factor ß (TGFß) mRNA, whereas the profibrotic cytokines interleukin 13 (IL13) and IL11 were upregulated in UC, suggesting that human postinjury responses could be TGFß-independent. In conclusion, we found distinct regulatory layers of regeneration in the normal human colon and a potential targetable profibrotic dysregulation in UC that could lead to long-term end-organ failure, i.e., intestinal damage.NEW & NOTEWORTHY The study reveals the regulatory dynamics of epithelial regeneration and extracellular matrix remodeling after experimental injury of the human colon in vivo and shows that human intestinal regeneration is different from data obtained from animals. A lag phase in epithelial restitution is associated with induction of stromal cell-derived epithelial growth factors. Postinjury regeneration is transforming growth factor ß-independent, and we find a profibrotic response in patients with ulcerative colitis despite being in remission.

Thiopurines and the Risk of Cancer in Patients With Inflammatory Bowel Disease and Reference Individuals Without Inflammatory Bowel Disease - A Danish Nationwide Cohort Study (1996-2018).

BACKGROUND & AIMS: Thiopurine therapy is a cornerstone in the treatment of inflammatory bowel disease (IBD). We aimed to assess the effect of thiopurines on cancer risk in IBD according to drug exposure and age. METHODS: Danish national registers were used to identify incident IBD patients, exposure to drugs, and status of cancers, in 1996 to 2018. Cox regressions were used to compare cancer risks in IBD and non-IBD individuals and to assess IBD patients' cumulative drug exposure and the association to first cancer, excluding non-melanoma skin cancer. RESULTS: We followed 43,419 patients with IBD for a median of 8.2 years (interquartile range, 3.7-14.2 years) after IBD diagnosis. Cancer was reported in 3128 (7.2%) patients with IBD. The risk of cancer was increased in patients with IBD in all age categories compared with non-IBD individuals (<50 years: adjusted hazard ratio [aHR], 1.59; 95% confidence interval [CI], 1.43-1.77; 50-65 years: aHR, 1.31; 95% CI, 1.19-1.44; and >65 years: aHR, 1.14; 95% CI, 1.05-1.24). Monotherapy (aHR, 1.36; 95% CI, 1.17-1.57) and combination therapy (aHR, 2.49; 95% CI, 1.64-3.78) were associated with an increased risk of cancer compared to unexposed patients with IBD. Among elderly patients (>65 years), the aHR was 2.79 (95% CI, 1.24-6.28) in those receiving combination therapy. In patients discontinuing thiopurines, aHRs returned to the level of unexposed (aHR, 0.89; 95% CI, 0.78-1.01). The aHR was positively associated with cumulative thiopurine exposure and in patients with >5 years of exposure, reaching an aHR of 1.36 (95% CI, 1.15-1.61). CONCLUSIONS: Thiopurines were associated with increased hazard of cancer, especially when used in combination therapy in the elderly. The hazard increased by 36% when patients were exposed to thiopurines for more than 5 years. Reassuringly, the hazard returned to baseline after discontinuation of thiopurines.

Infant Ustekinumab Clearance, Risk of Infection, and Development After Exposure During Pregnancy.

BACKGROUND: Evidence on ustekinumab safety in pregnancy is gradually expanding, but its clearance in the postnatal period is unknown. The aim of this study was to investigate ustekinumab concentrations in umbilical cord blood and rates of clearance after birth, as well as how these correlate with maternal drug concentrations, risk of infection, and developmental milestones during the first year of life. METHODS: Pregnant women with inflammatory bowel disease were prospectively recruited from 19 hospitals in Denmark and the Netherlands between 2018 and 2022. Infant infections leading to hospitalization/antibiotics and developmental milestones were assessed. Serum ustekinumab concentrations were measured at delivery and specific time points. Nonlinear regression analysis was applied to estimate clearance. RESULTS: In 78 live-born infants from 76 pregnancies, we observed a low risk of adverse pregnancy outcomes and normal developmental milestones. At birth, the median infant-mother ustekinumab ratio was 2.18 (95% confidence interval, 1.69-2.81). Mean time to infant clearance was 6.7 months (95% confidence interval, 6.1-7.3 months). One in 4 infants at 6 months had an extremely low median concentration of 0.015 µg/mL (range 0.005-0.12 µg/mL). No variation in median ustekinumab concentration was noted between infants with (2.8 [range 0.4-6.9] µg/mL) and without (3.1 [range 0.7-11.0] µg/mL) infections during the first year of life (P = .41). CONCLUSIONS: No adverse signals after intrauterine exposure to ustekinumab were observed with respect to pregnancy outcome, infections, or developmental milestones during the first year of life. Infant ustekinumab concentration was not associated with risk of infections. With the ustekinumab clearance profile, live attenuated vaccination from 6 months of age seems of low risk.

Spine and Sacroiliac Joint Involvement in Newly Diagnosed Patients With Inflammatory Bowel Disease: Clinical and MRI Findings From a Population-Based Cohort.

INTRODUCTION: In patients with inflammatory bowel disease (IBD), co-occurring spondyloarthritis (SpA) leads to poorer outcomes and impaired quality of life, highlighting the importance of early detection and effective treatment. This is the first study to assess the prevalence and distribution of axial symptoms and magnetic resonance imaging (MRI)-detected involvement of the spine and sacroiliac joints (SIJs) in early IBD. METHODS: Newly diagnosed patients with IBD from a prospective, population-based cohort were consecutively recruited. Rheumatological interview, clinical, ultrasound, and MRI assessment for SIJ and spine inflammatory and structural lesions were made using validated scoring methods and consensus definitions of axial SpA (axSpA). RESULTS: Of 110 patients (ulcerative colitis: 70, Crohn's disease: 40, mean age of 42 years, and 40% male), 48 (44.9%) reported back and/or buttock pain, and 10 (9.1%) had inflammatory back pain. Seventeen (16.7%) patients had MRI findings indicative of axSpA; only 10 of these patients had axial symptoms. Inflammatory MRI lesions were present in SIJs and the spine of 27 (26.5%) and 30 (30.3%) patients, respectively. The Assessment of SpondyloArthritis International Society classification criteria for axSpA were met in 11 (10%) cases. MRI findings typical of axSpA were associated with peripheral joint and entheseal inflammation detected by ultrasound ( P = 0.04). No differences in clinical or imaging findings were found between patients with ulcerative colitis and Crohn's disease. DISCUSSION: One-in-6 newly diagnosed patients with IBD had MRI findings indicative of axSpA. As 40% of these patients were asymptomatic, this suggests that axSpA is underdiagnosed in early IBD. Multidisciplinary collaboration is essential to ensure early detection of axial inflammation and to enable optimal therapy preventing future structural damage and disability.

IAPs and RIPK1 mediate LPS-induced cytokine production in healthy subjects and Crohn's disease.

Innate immune activity fuels intestinal inflammation in Crohn's disease (CD), an inflammatory bowel disease. Identification and targeting of new molecular regulators of the innate activity are warranted to control the disease. Inhibitor of apoptosis proteins (IAPs) regulate both cell survival and inflammatory signaling. We investigated the effects of IAP inhibition by second mitochondria-derived activator of caspases (SMAC) mimetics (SMs) on innate responses and cell death to pathogen-associated molecular patterns in peripheral blood mononuclear cells (PBMCs) and monocytes. IAPs inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory interleukin (IL)-1ß, IL-6. Likewise, LPS (but not muramyl dipeptide or Escherichia coli) induced TNF-α was inhibited in CD and control PBMCs. The SM effect was partially reversed by inhibition of receptor-interacting serine/threonine-protein kinase 1 (RIPK1). The effect was mainly cell death independent. Thus, IAP inhibition by SMs leads to reduced production of proinflammatory cytokines and may be considered in the efforts to develop new therapeutic strategies to control CD.

Development of an algorithm combining blood-based biomarkers, fecal immunochemical test, and age for population-based colorectal cancer screening.

BACKGROUND AND AIMS: Implementation of screening modalities have reduced the burden of colorectal cancer (CRC), but high false positive rates pose a major problem for colonoscopy capacity. We aimed to create a tailored screening algorithm that expands the fecal immunochemical test (FIT) with a blood specimen and current age to improve selection of individuals for diagnostic colonoscopy. METHODS: In this prospective multicenter study, 8 blood-based biomarkers (carcinoembryonic antigen, ferritin, high-sensitivity C-reactive protein, human epididymis protein 4, Cyfra21-1, hepsin, interleukin 8, and osteoprotegerin) were investigated in 1977 FIT-positive individuals from the Danish national CRC screening program undergoing follow-up colonoscopy. Specimens were analyzed on Architect i2000, Architect c8000 (both from Abbott, Chicago, IL, USA), or Luminex xMAP machines (MilliporeSigma, St. Louis, Mo, USA). FIT analyses and blood-based biomarker data were combined with clinical data (ie, age and colonoscopy findings) in a cross-validated logistic regression model (algorithm) benchmarked against a model solely using the FIT result (FIT model) applying different cutoffs for FIT positivity. RESULTS: The cohort included individuals with CRC (n = 240), adenomas (n = 938), or no neoplastic lesions (n = 799). The cross-validated algorithm combining the 8 biomarkers, quantitative FIT result, and age performed superior to the FIT model in discriminating CRC versus non-CRC individuals (area under the receiver operating characteristic curve, 0.77 vs 0.67, respectively; P < .001). When discriminating individuals with either CRC or high- or medium-risk adenomas versus low-risk adenomas or clean colorectum, the areas under the receiver operating characteristic curve were 0.68 versus 0.64 for the algorithm and FIT model, respectively. CONCLUSIONS: The algorithm presented here can improve patient allocation to colonoscopy, reducing colonoscopy burden without compromising cancer and adenoma detection rates or vice versa.

Prediction of Relapse After Anti-Tumor Necrosis Factor Cessation in Crohn's Disease: Individual Participant Data Meta-analysis of 1317 Patients From 14 Studies.

BACKGROUND & AIMS: Tools for stratification of relapse risk of Crohn's disease (CD) after anti-tumor necrosis factor (TNF) therapy cessation are needed. We aimed to validate a previously developed prediction model from the diSconTinuation in CrOhn's disease patients in stable Remission on combined therapy with Immunosuppressants (STORI) trial, and to develop an updated model. METHODS: Cohort studies were selected that reported on anti-TNF cessation in 30 or more CD patients in remission. Individual participant data were requested for luminal CD patients and anti-TNF treatment duration of 6 months or longer. The discriminative ability (concordance-statistic [C-statistic]) and calibration (agreement between observed and predicted risks) were explored for the STORI model. Next, an updated prognostic model was constructed, with performance assessment by cross-validation. RESULTS: This individual participant data meta-analysis included 1317 patients from 14 studies in 11 countries. Relapses after anti-TNF cessation occurred in 632 of 1317 patients after a median of 13 months. The pooled 1-year relapse rate was 38%. The STORI prediction model showed poor discriminative ability (C-statistic, 0.51). The updated model reached a moderate discriminative ability (C-statistic, 0.59), and included clinical symptoms at cessation (hazard ratio [HR], 2.2; 95% CI, 1.2-4), younger age at diagnosis (HR, 1.5 for A1 (age at diagnosis ≤16 years) vs A2 (age at diagnosis 17 - 40 years); 95% CI, 1.11-1.89), no concomitant immunosuppressants (HR, 1.4; 95% CI, 1.18-172), smoking (HR, 1.4; 95% CI, 1.15-1.67), second line anti-TNF (HR, 1.3; 95% CI, 1.01-1.69), upper gastrointestinal tract involvement (HR, 1.3 for L4 vs non-L4; 95% CI, 0.96-1.79), adalimumab (HR, 1.22 vs infliximab; 95% CI, 0.99-1.50), age at cessation (HR, 1.2 per 10 years younger; 95% CI, 1-1.33), C-reactive protein (HR, 1.04 per doubling; 95% CI, 1.00-1.08), and longer disease duration (HR, 1.07 per 5 years; 95% CI, 0.98-1.17). In subanalysis, the discriminative ability of the model improved by adding fecal calprotectin (C-statistic, 0.63). CONCLUSIONS: This updated prediction model showed a reasonable discriminative ability, exceeding the performance of a previously published model. It might be useful to guide clinical decisions on anti-TNF therapy cessation in CD patients after further validation.

Coronavirus disease 2019, immune-mediated inflammatory diseases and immunosuppressive therapies - A Danish population-based cohort study.

BACKGROUND: Limited data exist regarding the disease course of coronavirus disease 2019 (COVID-19) and its relationship with immunosuppressants among patients with immune-mediated inflammatory diseases (IMIDs). Therefore, this study aims to investigate the association between COVID-19, frequent rheumatological, dermatological, gastrointestinal, and neurological IMIDs and immunosuppressants. METHODS: We conducted a Danish population-based cohort study including all residents living within Capital Region of Denmark and Region Zealand from January 28th, 2020 until September 15th, 2020 with the only eligibility criterion being a test for SARS-CoV-2 via reverse transcription-polymerase chain-reaction. Main outcomes included development of COVID-19, COVID-19-related hospitalization and mortality. RESULTS: COVID-19 was less common among patients with IMIDs than the background population (n = 328/20,513 (1.60%) and n = 10,792/583,788(1.85%), p < 0.01, respectively). However, those with IMIDs had a significantly higher risk of COVID-19-related hospitalization (31.1% and 18.6%, p < 0.01, respectively) and mortality (9.8% and 4.3%, p < 0.01, respectively), which were associated with patients older than 65 years, and presence of comorbidities. Furthermore, systemic steroids were independently associated with a severe course of COVID-19 (Odds ratio (OR) = 3.56 (95%CI 1.83-7.10), p < 0.01), while biologic therapies were associated with a reduced risk hereof (OR = 0.47 (95%CI 0.22-0.95), p = 0.04). Patients suspending immunosuppressants due to COVID-19 had an increased risk of subsequent hospitalization (OR = 3.59 (95%CI 1.31-10.78), p = 0.02). CONCLUSION: This study found a lower occurrence, but a more severe disease course, of COVID-19 among patients with IMIDs, which was associated with the use of systemic steroids for IMIDs and suspension of other immunosuppressants. This study emphasizes the importance of weighing risks before suspending immunosuppressants during COVID-19.

Efficacy of ustekinumab for active perianal fistulizing Crohn's disease: a systematic review and meta-analysis of the current literature.

BACKGROUND: Although the number of biological therapies for the treatment of Crohn's disease (CD) is rapidly increasing, their efficacy in inducing healing of fistulas in perianal Crohn's disease (pCD) is practically unknown, although they occur in up to 50% of patients with CD. OBJECTIVE: We aimed to investigate the clinical effectiveness of ustekinumab for pCD in a systemic review and meta-analysis. METHODS: Studies describing the efficacy of ustekinumab on fistulas in pCD in PubMed and EMBASE database from inception until 22 September 2020, were assessed in a systemic review and meta-analysis. The random-effect model was applied for the meta-analysis. RESULTS: The systematic review of the current literature yielded 2,243 studies of which nine studies with a total of 396 patients were found eligible for inclusion. The pooled proportions of patients experiencing fistula response were 41.0% (95% CI 23.9-60.6%9), I 2 = 85%, 39.7% (95% CI 24.3-57.4%), I 2 = 69% and 55.9% (95% CI 40.8-69.9%, I 2 = 67% at weeks 8, 24, and 52, respectively. Regarding fistula remission, the pooled proportions were 17.1% (95% CI 8.1-32.7%), I 2 = 45%, 17.7% (95% CI 1.8-71.9%), I 2 = 68%, and 16.7% (95% CI 3.0-56.5%, I 2 = 51% at week 8, 24, and 52, respectively. CONCLUSION: In this systematic review with meta-analysis, we found a signal of efficacy of ustekinumab on fistulizing pCD, emphasizing that these patients might benefit from this therapy.

Vedolizumab as first-line biological therapy in elderly patients and those with contraindications for anti-TNF therapy: a real-world, nationwide cohort of patients with inflammatory bowel diseases.

BACKGROUND: Data from real-life populations about vedolizumab as first-line biological therapy for ulcerative colitis (UC) and Crohn's disease (CD) are emerging. OBJECTIVE: To investigate the efficacy and safety of vedolizumab in bio-naïve patients with UC and CD. METHODS: A Danish nationwide cohort study was conducted between November 2014 and November 2019. Primary outcomes were clinical remission, steroid-free clinical remission, and sustained clinical remission from weeks 14 through 52. RESULTS: The study included 56 patients (UC:31, CD:25) who initiated treatment with vedolizumab mainly because of contraindications to anti-TNFs, of whom 54.8 and 24.0%, respectively received systemic steroids at the initiation. Rates of clinical remission at weeks 6, 14, and 52 were 32.0, 48.0, and 40.0%, respectively, in UC, and 36.8, 36.8, and 47.4% in CD. Steroid-free clinical remission at week 52 was achieved among 36.0 and 47.4% of UC and CD patients, while sustained clinical remission was achieved in 32.0 and 36.8%. Lack of remission was associated with being female (68.8 vs. 11.1%, p = .01) in UC and non-structuring, non-penetrating behavior in CD (90.0 vs. 44.4%, p = .03); however, this was not confirmed in multivariate analysis. Discontinuation due to primary non-response occurred in 20.0 and 5.3% of UC and CD patients, respectively, while rates of secondary loss of response were 12.0 and 5.3% after 52 weeks of follow-up. Vedolizumab was well-tolerated as only one UC patient experienced a serious adverse event. CONCLUSION: Vedolizumab is effective in the achievement of short-term, long-term, and steroid-free clinical remission in bio-naïve UC and CD patients.

Asymptomatic Carriers Contribute to Nosocomial Clostridium difficile Infection: A Cohort Study of 4508 Patients.

BACKGROUND & AIMS: Nosocomial infections with Clostridium difficile present a considerable problem despite numerous attempts by health care workers to reduce risk of transmission. Asymptomatic carriers of C difficile can spread their infection to other patients. We investigated the effects of asymptomatic carriers on nosocomial C difficile infections. METHODS: We performed a population-based prospective cohort study at 2 university hospitals in Denmark, screening all patients for toxigenic C difficile in the intestine upon admittance, from October 1, 2012, to January 31, 2013. Screening results were blinded to patients, staff, and researchers. Patients were followed during their hospital stay by daily registration of wards and patient rooms. The primary outcomes were rate of C difficile infection in exposed and unexposed patients and factors associated with transmission. RESULTS: C difficile infection was detected in 2.6% of patients not exposed to carriers and in 4.6% of patients exposed to asymptomatic carriers at the ward level (odds ratio for infection if exposed to carrier, 1.79; 95% confidence interval, 1.16-2.76). Amount of exposure correlated with risk of C difficile infection, from 2.2% in the lowest quartile to 4.2% in the highest quartile of exposed patients (P = .026). Combining the load of exposure to carriers and length of stay seemed to have an additive effect on the risk of contracting C difficile. CONCLUSIONS: In a population-based prospective cohort study in Denmark, we found that asymptomatic carriers of toxigenic C difficile in hospitals increase risk of infection in other patients.

Cellular inhibitor of apoptosis protein 2 controls human colonic epithelial restitution, migration, and Rac1 activation.

Identification of pathways involved in wound healing is important for understanding the pathogenesis of various intestinal diseases. Cellular inhibitor of apoptosis protein 2 (cIAP2) regulates proliferation and migration in nonepithelial cells and is expressed in human colonocytes. The aim of the study was to investigate the role of cIAP2 for wound healing in the normal human colon. Wound tissue was generated by taking rectosigmoidal biopsies across an experimental ulcer in healthy subjects after 5, 24, and 48 h. In experimental ulcers, the expression of cIAP2 in regenerating intestinal epithelial cells (IECs) was increased at the wound edge after 24 h (P < 0.05), returned to normal after reepithelialization, and correlated with the inflammatory reaction in the experimental wounds (P < 0.001). cIAP2 was induced in vitro in regenerating Caco2 IECs after wound infliction (P < 0.01). Knockdown of cIAP2 caused a substantial impairment of the IEC regeneration through inhibition of migration (P < 0.005). cIAP2 overexpression lead to formation of migrating IECs and upregulation of expression of RhoA and Rac1 as well as GTP-activation of Rac1. Transforming growth factor-ß1 enhanced the expression of cIAP2 but was not upregulated in wounds in vivo and in vitro. NF-κB and MAPK pathways did not affect cIAP2 expression. cIAP2 is in conclusion a regulator of human intestinal wound healing through enhanced migration along with activation of Rac1, and the findings suggest that cIAP2 could be a future therapeutic target to improve intestinal wound healing.

Regulation of antiapoptotic and cytoprotective pathways in colonic epithelial cells in ulcerative colitis.

Ulcerative colitis is an inflammatory bowel disease involving the colon resulting in bloody diarrhea and increased risk of colorectal cancer in certain patient subgroups. Increased apoptosis in the epithelial cell layer causes increased permeability, especially during flares; this leads to translocation of luminal pathogens resulting in a continued inflammatory drive. The present work investigates how epithelial apoptosis is regulated in ulcerative colitis. The main results are that Fas mediated apoptosis is inhibited during flares of ulcerative colitis, probably by an upregulation of cellular inhibitor of apoptosis protein 2 (cIAP2) and cellular FLICE-like inhibitory protein. cIAP2 is upregulated in regenerative epithelial cells both in ulcerative colitis and in experimental intestinal wounds. Inhibition of cIAP2 decreases wound healing in vitro possibly through inhibition of migration. Altogether, it is shown that epithelial cells in ulcerative colitis responds to the hostile microenvironment by activation of cytoprotective pathways that tend to counteract the cytotoxic effects of inflammation. However, the present studies also show that epithelial cells produce increased amounts of reactive oxygen species during stimulation with tumor necrosis factor-α and interferon-γ resulting in DNA instability. The combined effect of increased DNA-instability and decreased apoptosis responses could lead to neoplasia.

Muramyl dipeptide responsive pathways in Crohn's disease: from NOD2 and beyond.

Crohn's disease (CD) is one of main disease entities under the umbrella term chronic inflammatory bowel disease. The etiology of CD involves alterations in genetic, microbiological, and immunological factors. This review is devoted to the role of the bacterial wall compound muramyl dipeptide (MDP) for the activation of inflammatory pathways involved in the pathogenesis of CD. The importance of this molecule is underscored by the fact that (1) MDP, which is found in most Gram-negative and -positive bacteria, is able to trigger several immunological responses in the intestinal system, and (2) that alterations in several mediators of the MDP response including-but not restricted to-nucleotide oligomerization domain 2 (NOD2) are associated with CD. The normalization of MDP signaling is one of several important factors that influence the intestinal inflammatory response, a fact which emphasizes the pathogenic importance of MDP signaling for the pathogenesis of CD. The important aspects of NOD2 and non-NOD2 mediated effects of MDP for the development of CD are highlighted, as well as how alterations in these pathways might translate into the development of new therapeutic strategies.

Biologics and targeted synthetic medicines for ulcerative colitis and Crohn's disease.

Ulcerative colitis and Crohn's disease are chronic inflammatory bowel diseases. Recent pivotal phase 3 trials involving treatments like interleukin-23-, sphingosin-1-phosphate- and Janus kinase inhibitors have demonstrated notable effectiveness. However, they have also unveiled significant side effects such as herpes zoster, lymphopenia and bradycardia. The introduction of novel treatments raises valid concerns necessitating increased collaboration with diverse medical specialities to address potentially severe side effects, and this is vital for enhancing the future care of individuals with inflammatory bowel diseases, as argued in this review.

Intestinal ultrasound in inflammatory bowel disease.

Intestinal ultrasound (IUS) is non-invasive, fast, cheap, and well-tolerated and requires no preparation and is thus applicable as a point-of-care monitoring tool of inflammatory bowel disease (IBD). Evidence suggests that IUS is comparable to other standard monitoring modalities, i.e., endoscopy, MRI, calprotectin, and C-reactive protein and might be more accurate in predicting response to treatment at an early stage consequently allowing for timely optimised treatment. This review finds that integrating IUS as the standard of care in every IBD outpatient clinic and as the primary outcome in future medical trials seems inevitable.