Appendectomy and protection against ulcerative colitis

Appendiceal periappendicitis and ulcerative colitis: Relationship and research advances

The prevalence of ulcerative colitis (UC) has been increasing in China, reaching about 11.6 per 100000. The diagnostic process for this disease is extremely lengthy and complex, significantly impacting the patient's health. UC typically starts in the rectum and sigmoid colon, and when patients with distal colitis also present with appendiceal periappendicitis, this condition is considered a "skip lesion" of UC. This phenomenon may be related to the appendix's role as an immune organ and its immunological connection to the pathogenesis of UC. Appendiceal periappendicitis combined with rectal inflammation can facilitate the diagnosis of UC. However, there is still no consensus on the pathogenesis, treatment prognosis, and clinical significance of appendiceal periappendicitis. This paper reviews the recent literature and provides a comprehensive analysis of appendiceal periapp-endicitis.

Prior Appendicectomy and Gut Microbiota Re-Establishment in Adults after Bowel Preparation and Colonoscopy

Emerging evidence suggests that the human vermiform appendix is not a vestigial organ but rather an immunological organ of biological relevance. It is hypothesised that the appendix acts as a bacterial 'safe house' for commensal gut bacteria and facilitates re-inoculation of the colon after disruption through the release of biofilms. To date, no studies have attempted to explore this potential mechanistic function of the appendix. We conducted a pre-post intervention study in adults (n = 59) exploring re-establishment of the gut microbiota in those with and without an appendix after colonic disruption via bowel preparation and colonoscopy. Gut microbiota composition was measured one week before and one month after bowel preparation and colonoscopy using 16S rRNA sequencing. We observed between group differences in gut microbiota composition between those with (n = 45) and without (n = 13) an appendix at baseline. These differences were no longer evident one-month post-procedure, suggesting that this procedure may have 'reset' any potential appendix-related differences between groups. Both groups experienced reductions in gut microbiota richness and shifts in beta diversity post-procedure, with greater changes in those without an appendix, and there were five bacterial genera whose re-establishment post-procedure appeared to be moderated by appendicectomy status. This small experimental study provides preliminary evidence of a potential differential re-establishment of the gut microbiota after disruption in those with and without an appendix, warranting further investigation into the potential role of the appendix as a microbial safe house.

Antibiotic Use in the 12 Months Prior to Ileal Pouch-Anal Anastomosis Increases the Risk for Pouchitis

BACKGROUND & AIMS

Pouchitis is the most common complication after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC); however, clinical and environmental risk factors for pouchitis remain poorly understood. We explored the relationship between specific clinical factors and the incidence of pouchitis.

METHODS

We established a population-based cohort of all adult persons in Denmark undergoing proctocolectomy with IPAA for UC from 1996-2020. We used Cox proportional hazard modeling to assess the impact of antibiotic, nonsteroidal anti-inflammatory drug (NSAID) exposure, and appendectomy on diagnosis of acute pouchitis in the first 2 years after IPAA surgery.

RESULTS

Among 1616 eligible patients, 46% developed pouchitis in the first 2 years after IPAA. Antibiotic exposure in the 12 months before IPAA was associated with an increased risk of pouchitis (adjusted hazard ratio [aHR], 1.41; 95% confidence interval [CI], 1.22-1.64) after adjusting for anti-tumor necrosis factor alpha use and sex. Compared with persons without any antibiotic prescriptions in the 12 months before IPAA, the risk of pouchitis was increased in those with 1 or 2 courses of antibiotics in that period (aHR, 1.30; 95% CI, 1.11-1.52) and 3 or more courses (aHR, 1.77; 95% CI, 1.41-2.21). NSAID exposure in the 12 months before IPAA and appendectomy were not associated with risk of acute pouchitis (P = .201 and P = .865, respectively).

CONCLUSIONS

In this population-based cohort study, we demonstrated that antibiotic exposure in the 12 months before IPAA is associated with an increased risk of acute pouchitis. Future prospective studies may isolate specific microbial changes in at-risk patients to drive earlier interventions.

Association of diet and outdoor time with inflammatory bowel disease: a multicenter case-control study using propensity matching analysis in China

Objective

To investigate the association between dietary and some other environmental factors and the risk of inflammatory bowel diseases (IBD) in Chinese population.

Materials and methods

A multicenter case-control study was conducted involving 11 hospitals across China. A total of 1,230 subjects were enrolled consecutively, and diet and environmental factor questionnaires were collected. IBD patients were matched with healthy controls (HC) using propensity-score matching (PSM) at a 1:1 ratio with a caliper value of 0.02. Multivariate conditional logistic regression analyses were performed to evaluate the associations between diet, environmental factors, and IBD.

Results

Moderate alcohol and milk consumption, as well as daily intake of fresh fruit, were protective factors for both Crohn's disease (CD) and ulcerative colitis (UC). Conversely, the consumption of eggs and chocolate increased the risk of IBD. Outdoor time for more than 25% of the day was a protective factor only for CD. In eastern regions of China, CD patients had higher egg consumption and less outdoor time, while UC patients consumed more chocolate. IBD patients from urban areas or with higher per capita monthly income consumed more fruit, eggs, and chocolate.

Conclusions

This study reveals an association between specific foods, outdoor time, and the emergence of IBD in the Chinese population. The findings emphasize the importance of a balanced diet, sufficient outdoor time and activities, and tailored prevention strategies considering regional variations.

Epidemiologic profile of inflammatory bowel disease in Eastern Mediterranean Region (EMRO) countries: a systematic review and meta-analysis

BACKGROUND

Inflammatory bowel disease (IBD) consists of two main types: Crohn's disease (CD) and ulcerative colitis (UC). The epidemiology of IBD patients has not been comprehensively studied in EMRO countries; therefore, we conducted this meta-analysis to study the epidemiology of this disease in these countries.

METHODS

We searched four international databases, namely Scopus, Web of Knowledge (ISI), Medline/PubMed, and ProQuest, from inception up to the end of May 2023. The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guideline was used to carry out this systematic review and meta-analysis investigation. Using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist, the quality of the selected papers was assessed.

RESULTS

Based on the results of this study, the incidence of UC in EMRO countries was 2.65 per 100,000 (95% CI: 1.39-3.90), and the incidence of CD was 1.16 per 100,000 (95% CI: 0.73-1.59). The most commonly involved intestinal segment in CD was the terminal ileum (44.7%, 95% CI: 34.7-55.2), followed by the ileum (29.8%, 95% CI: 22.2-38.6), and colon (18.7%, 95% CI: 10.8-30.4). However, in UC patients, extensive colitis was the most common finding (32.3%, 95% CI: 26.4-38.8), followed by proctosigmoiditis (27.9%, 95% CI: 21.1-35.8), left-sided colitis (27.4%, 95% CI: 22.7-32.7), and proctitis (22.6%, 95% CI: 17.5-28.5).

CONCLUSION

As a result, we were able to establish the traits of IBD patients in EMRO nations. UC patients had a higher incidence than CD patients. The most common regions of involvement in CD and UC patients, respectively, were the colon and pancolitis. Compared to UC patients, CD patients had a higher history of appendectomy.

Environmental and Microbial Factors in Inflammatory Bowel Disease Model Establishment: A Review Partly through Mendelian Randomization

Inflammatory bowel disease (IBD) is a complex condition resulting from environmental, microbial, immunologic, and genetic factors. With the advancement of Mendelian randomization research in IBD, we have gained new insights into the relationship between these factors and IBD. Many animal models of IBD have been developed using different methods, but few studies have attempted to model IBD by combining environmental factors and microbial factors. In this review, we examine how environmental factors and microbial factors affect the development and progression of IBD, and how they interact with each other and with the intestinal microbiota. We also summarize the current methods for creating animal models of IBD and compare their advantages and disadvantages. Based on the latest findings from Mendelian randomization studies on the role of environmental factors in IBD, we discuss which environmental and microbial factors could be used to construct a more realistic and reliable IBD experimental model. We propose that animal models of IBD should consider both environmental and microbial factors to better mimic human IBD pathogenesis and to reveal the underlying mechanisms of IBD at the immune and genetic levels. We highlight the importance of environmental and microbial factors in IBD pathogenesis and offer new perspectives and suggestions for improving experimental animal modeling. Our goal is to create a model that closely resembles the clinical picture of IBD.

Is there a link between appendicitis and the risk of diverticular disease?: a large German cohort study

PURPOSE

Appendicitis, characterized by inflammation of the vermiform appendix, is a common abdominal emergency necessitating appendectomy. Recent evidence suggests a potential link between appendicitis and subsequent diverticular disease, yet population-based studies investigating this association are limited.

METHODS

Utilizing the Disease Analyzer database encompassing data from over 1000 primary care practices in Germany, we conducted a retrospective cohort study. We included 25,379 adults diagnosed with appendicitis and an equal number of matched controls without appendicitis. The incidence of diverticular disease over a 10-year follow-up period was compared between the two cohorts. Cox regression analysis was performed to assess the association between appendicitis and diverticular disease, adjusting for potential confounders.

RESULTS

Our findings revealed a significant association between appendicitis and subsequent diverticular disease (HR: 1.76; 95% CI: 1.57-1.97), with an increased risk observed across all age groups. Notably, this association was stronger in men (HR: 2.00; 95% CI: 1.68-2.37) than in women (HR: 1.58; 95% CI: 1.36-1.84). The cumulative 10-year incidence of diverticular disease was higher in patients with appendicitis (6.5%) compared to those without (3.6%). Additionally, we observed a clear age-dependent increase in the incidence of diverticular disease.

CONCLUSION

This large-scale population-based study provides valuable insights into the interaction between appendicitis and diverticular disease. The study underscores the need for further research elucidating the underlying mechanisms linking appendicitis to diverticular disease. Probiotics emerge as a potential therapeutic avenue warranting exploration in the management of both conditions. These findings have important implications for clinical practice, highlighting the importance of considering appendicitis as a potential risk factor for diverticular disease, particularly in men. Further investigation is warranted to validate these findings and explore potential therapeutic interventions targeting the shared pathophysiological pathways underlying both conditions.

Long-term outcomes after appendicectomy as experimental treatment for patients with therapy-refractory ulcerative colitis

This study assessed 25 patients with severe ulcerative colitis undergoing appendicectomy. During a median postoperative follow-up of 7.5 years, the median duration of clinical response, as observed in 15 patients, was 80 months; the median duration of endoscopic improvement, as observed in 12 of patients, was 46 months.

Relationship between human herpesvirus 6 infection and inflammatory bowel disease using novel biomarker

Objective

Inflammatory bowel disease (IBD) is closely related to stress and fatigue. Human herpesvirus 6B (HHV-6B) is reactivated by stress and fatigue and is associated with IBD. This study aimed to clarify the relationship between IBD and HHV-6B.

Methods

Antibody titers to SITH-1, a protein specific to HHV-6B latent infection, were measured in 163 patients with IBD (107 with ulcerative colitis [UC] and 56 with Crohn's disease [CD]); clinical and endoscopic scores and depression scores of UC and CD were analyzed to examine the relationship between SITH-1 and IBD. The SITH-1 cut-off value was set as 1.96, according to known reports.

Results

In patients with UC, C-reactive protein (CRP) level was significantly higher (1.5 vs 0.6 mg/L, P = 0.006) and disease exacerbation within 6 months after entry was significantly more common in the SITH-1 (+) group (20% vs 0%, P < 0.001). In the subanalysis comparing with and without UC exacerbation, the optimal cut-off value for SITH-1 to detect UC exacerbation was 3.44 (area under the curve: 0.81; 95% confidence interval: 0.72-0.90). CRP levels, SITH-1 levels, and disease activity scores by the clinical or endoscopic index were significantly higher in the exacerbation group than in the non-exacerbation group (2.6 vs 0.9 mg/L, P = 0.03; 4.90 vs 1.71, P < 0.001; 4 vs 3, P = 0.03; 5 vs 3, P = 0.02; respectively).

Conclusion

Patients with UC with high titers of SITH-1 have high disease activity and frequent disease exacerbation. SITH-1 can be associated with UC disease activity.

The appendix and ulcerative colitis - an unsolved connection

The appendix is thought to have a role in the pathogenesis of ulcerative colitis, but the nature and basis of this association remains unclear. In this Perspective, we consider the biology of the appendix with respect to its immunological function and the microbiome, and how this relates to evidence that supports the involvement of the appendix in ulcerative colitis. In experimental models, removal of the inflamed appendix prevents colitis, and in human observational studies, appendectomy is associated with protection against ulcerative colitis. Further, among people who develop ulcerative colitis, appendectomy before diagnosis might influence the course and outcomes of the disease - some evidence suggests that it protects against colectomy but could increase the risk of colorectal cancer. Appendectomy after onset of ulcerative colitis seems to have disparate consequences. Clinical trials to understand whether appendectomy has a role in the treatment of ulcerative colitis are ongoing. Major questions about the role of the appendix in the pathogenesis of ulcerative colitis remain unanswered, and further research is needed to establish whether the connection is clinically relevant.

Evaluation of appendectomy as a potential risk factor for immune checkpoint inhibitor-associated enterocolitis

Aims: The relationship between appendectomy and immune checkpoint inhibitor (ICI) enterocolitis was explored. Methods: Patients who began ICIs between July 2010 and September 2020 (n = 10,907) were included. The exposure group included patients with evidence of appendectomy prior to ICIs in operative notes (n = 380). The control group included patients with evidence of normal appendix in radiologic reports (n = 3602). ICI enterocolitis was defined as histopathologic evidence of colitis or enteritis attributed to ICIs. The association between appendectomy and ICI enterocolitis was characterized by multivariate logistic regression. Results: 248 patients (6.2%) developed ICI enterocolitis. The odds of ICI enterocolitis were similar among those with prior appendectomy and those without appendectomy (adjusted odds ratio: 0.82; 95% CI: 0.49-1.36; p = 0.449). Conclusion: No association was found between prior appendectomy and ICI enterocolitis.

Human intestinal B cells in inflammatory diseases

The intestinal lumen contains an abundance of bacteria, viruses and fungi alongside ingested material that shape the chronically active intestinal immune system from early life to maintain the integrity of the gut epithelial barrier. In health, the response is intricately balanced to provide active protection against pathogen invasion whilst tolerating food and avoiding inflammation. B cells are central to achieving this protection. Their activation and maturation generates the body's largest plasma cell population that secretes IgA, and the niches they provide support systemic immune cell specialization. For example, the gut supports the development and maturation of a splenic B cell subset - the marginal zone B cells. In addition, cells such as the T follicular helper cells, which are enriched in many autoinflammatory diseases, are intrinsically associated with the germinal centre microenvironment that is more abundant in the gut than in any other tissue in health. In this Review, we discuss intestinal B cells and their role when a loss of homeostasis results in intestinal and systemic inflammatory diseases.

Disturbed Pediatric Gut Microbiome Maturation in the Developmental Origins of Subsequent Chronic Disease

The microbiome is known to play an important role in the development and maintenance of human health. During early childhood the gut microbiome undergoes a rapid evolution, making this developmental window most susceptible to microbial manipulation and, therefore, most vulnerable to environmental stimuli. Such stimuli may induce persistent alterations (or dysbiosis) in microbiome and/or host physiology, thereby resulting in susceptibility to subsequent disease development. This phenomenon is frequently described as "the microbial developmental origins of disease." In this topic of the month, we call attention to the microbial developmental origins of disease by examining the potential for childhood antibiotic exposures and appendectomy (ie, inducers of dysbiosis) to influence the pathogenesis of certain multifactorial, common diseases (eg, celiac disease, inflammatory bowel disease, obesity), especially those with increasing incidence worldwide. We conclude that fully appreciating the critical components in the microbial developmental origins of common chronic disorders is a major task ahead of pediatric gastroenterologists in the 21st century. Such information will be key in working to prevent numerous common and emerging disorders.

Appendectomy and Future Risk of Microscopic Colitis: A Population-Based Case-Control Study in Sweden

BACKGROUND AND AIMS

Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied.

METHODS

This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis.

RESULTS

The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40-1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48-1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30-1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis.

CONCLUSIONS

This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.

Intestinal ultrasound detects an increased diameter and submucosal layer thickness in the appendix of patients with ulcerative colitis compared to healthy controls - a prospective cohort study

BACKGROUND

Increasing evidence suggests that appendicectomy as alternative treatment for ulcerative colitis (UC), especially in patients with histopathological appendiceal inflammation. Intestinal ultrasound (IUS) is a non-invasive diagnostic modality to characterise appendiceal inflammation.

AIMS

To assess appendiceal IUS characteristics in UC patients and compare findings to healthy controls (HC).

METHODS

In this prospective study, appendiceal IUS was performed in consecutive UC patients with active (A; n = 35) or quiescent (Q; n = 30) disease and in HC (n = 30). Transverse appendiceal diameter (TAD) and additional IUS parameters (bowel wall thickness, submucosal layer thickness and colour Doppler signal) were assessed.

RESULTS

The appendix was visualised in 41/65 UC patients (63.1%; A vs. Q: 23/35 vs. 18/30, p = 0.67) and 18/30 (60%) HC. UC patients had a higher TAD (A: 5.5 mm, Q: 5.0 mm, HC: 4.3 mm; A-HC p < 0.01; Q-HC p = 0.01, A-Q p = ns) and submucosal layer thickness (A: 1.0 mm, Q: 1.0 mm, HC: 0.7 mm; A-HC p < 0.01, Q-HC: p = 0.01, A-Q: p = ns) when compared to HC. A TAD ≥6 mm corresponding to an ultrasonographic suspicion of acute appendicitis was mainly reported in A-UC patients (A: 43%; Q: 6%; HC: 0%, p = 0.01) and occurred irrespective of disease extent. However, none of the patients had a clinical suspicion of acute appendicitis.

CONCLUSION

A TAD ≥6 mm was predominantly seen in A-UC. TAD was higher in UC patients compared to HC irrespective of disease activity and was characterised by an increased submucosal layer thickness. IUS therefore has the potential to identify UC patients with appendiceal inflammation.

The Appendix Orchestrates T-Cell Mediated Immunosurveillance in Colitis-Associated Cancer

BACKGROUND & AIMS

Although appendectomy may reduce colorectal inflammation in patients with ulcerative colitis (UC), this surgical procedure has been suggested to be associated with an increased risk of colitis-associated cancer (CAC). Our aim was to explore the mechanism underlying the appendectomy-associated increased risk of CAC.

METHODS

Five-week-old male BALB/c mice underwent appendectomy, appendicitis induction, or sham laparotomy. They were then exposed to azoxymethane/dextran sodium sulfate (AOM/DSS) to induce CAC. Mice were killed 12 weeks later, and colons were taken for pathological analysis and immunohistochemistry (CD3 and CD8 staining). Human colonic tumors from 21 patients with UC who underwent surgical resection for CAC were immunophenotyped and stratified according to appendectomy status.

RESULTS

Whereas appendectomy significantly reduced colitis severity and increased CAC number, appendicitis induction without appendectomy led to opposite results. Intratumor CD3+ and CD8+ T-cell densities were lower after appendectomy and higher after appendicitis induction compared with the sham laparotomy group. Blocking lymphocyte trafficking to the colon with the anti-α4β7 integrin antibody or a sphingosine-1-phosphate receptor agonist suppressed the inducing effect of the appendectomy on tumors' number and on CD3+/CD8+ intratumoral density. CD8+ or CD3+ T cells isolated from inflammatory neo-appendix and intravenously injected into AOM/DSS-treated recipient mice increased CD3+/CD8+ T-cell tumor infiltration and decreased tumor number. In UC patients with a history of appendectomy, intratumor CD3+ and CD8+ T-cell densities were decreased compared with UC patients without history of appendectomy.

CONCLUSIONS

In UC, appendectomy could suppress a major site of T-cell priming, resulting in a less efficient CAC immunosurveillance.

Acute appendicitis and ulcerative colitis: a population-based sibling comparison study

OBJECTIVE

To assess the inverse relationship between acute appendicitis and ulcerative colitis (UC) using a sibling comparison design to adjust for unmeasured familial genetic and environmental factors.

DESIGN

The cohort comprised 3.1 million individuals resident in Sweden between 1984 and 2018 with the linkage of several Swedish national registers. Fitting Cox hazards models, we calculated the risk for developing UC in individuals with and without acute appendicitis by the age 20 years adjusting for several potential confounding factors. Further, we performed sibling-stratified analyses to adjust for shared unmeasured familial confounding factors.

RESULTS

During 57.7 million person-years of follow-up, 20 848/3 125 232 developed UC among those without appendicitis (3.63 (3.59-3.68) per 10 000 person-years), whereas only 59/35 848 people developed UC among those with appendicitis before age 20 years (1.66 (1.28-2.14) per 10 000 person-years). We found a decreased risk for developing UC in those with acute appendicitis by the age 20 years compared with individuals who did not have appendicitis by this age (HR=0.37 (95% CI 0.29 to 0.48)). When adjusting for shared familial confounders, we observed only a slight attenuation in this association (HR=0.46 (95% CI 0.32 to 0.66)).

CONCLUSION

Individuals who had acute appendicitis by late adolescence showed a decreased risk for developing UC compared with those who did not. Genetic and shared familial environmental factors seem to potentially play only a small role in this relationship. Our results suggest an independent association of acute appendicitis, or its underlying causes, with UC risk.

Implications of the changing epidemiology of inflammatory bowel disease in a changing world

The epidemiology of inflammatory bowel disease (IBD) has undergone considerable shifts since its emergence in the Western world over a century ago, especially in the last few decades, with increasing global burden of disease. IBD incidence continues to rise in developed countries in all age groups which is contributing to compounding prevalence. Further, IBD incidence is rising sharply in Asia and other recently developed and developing countries. In this review, we discuss the implications of changing trends of IBD epidemiology. First, changing patterns provide insights into IBD causes, as they occur concurrent with shifts in the environment, cultures, and attitudes. Understanding the impact of the environment on IBD risk can help towards prediction and prevention strategies. Second, we must prepare healthcare systems for the rising burden of IBD and address it at various levels towards improving outcomes and health, overall.

Childhood appendicitis and future risk of inflammatory bowel disease - A nationwide cohort study in Sweden 1973-2017

AIM

The aim of this study was to investigate the association between juvenile appendicitis, treated conservatively or with appendectomy, and adult risk of inflammatory bowel disease (IBD), either ulcerative colitis (UC) or Crohn's disease (CD). We used nationwide population data from more than 100,000 individuals followed for over four decades.

METHOD

All Swedish patients discharged with a diagnosis of appendicitis before the age of 16 years between 1973 to 1996 were identified. Everyone diagnosed with appendicitis was matched to an individual in the general population without a history of juvenile appendicitis (unexposed) of similar age, sex and region of residence. The study population was retrospectively followed until 2017 for any development of UC or CD. Cox proportional-hazards models compared disease-free survival time between exposed and unexposed individuals, also analysing the impact of treatment (conservative treatment versus appendectomy).

RESULTS

The final cohort consisted of 52,391 individuals exposed to appendicitis (1,674,629 person years) and 51,415 unexposed individuals (1,638,888 person years). Childhood appendicitis with appendectomy was associated with a significantly lower risk of adult IBD [adjusted hazard ratio (aHR) 0.48 (0.42-0.55)], UC [aHR 0.30 (0.25-0.36)] and CD [aHR 0.82 (0.68-0.97)]. Those treated conservatively had a lower risk of adult UC [aHR 0.29 (0.12-0.69)] but not CD [aHR 1.12 (0.61-2.06)] compared with unexposed individuals.

CONCLUSION

Juvenile appendicitis treated with appendectomy was associated with a decreased risk of adult IBD, both UC and CD. Those treated conservatively instead of with surgery had a lower risk of UC only. Our findings warrant more research on the role of the appendix and gut microbiota in the pathogenesis of IBD.

Appendectomy and risk for inflammatory bowel disease: effect of age and time post appendectomy - a cohort study

Background and objective

Appendectomy may modulate the risk of inflammatory bowel disease through an effect on the gut microbiota. This study investigated the associations between appendectomy and incidence of Crohn’s disease (CD) or ulcerative colitis (UC), with an emphasis on the influence of age and time post appendectomy.

Methods

This cohort study included 400 520 subjects born in Québec in 1970–1974 and followed until 2014. Administrative health data were used to ascertain appendectomy and cases of CD and UC. Cox proportional hazards models with time-dependent variables (appendectomy and time elapsed post appendectomy) allowed for the estimation of HRs and 95% CIs.

Results

A total of 2545 (0.6%) CD cases and 1134 (0.3%) UC cases were identified during follow-up. Appendectomy increased the risk of CD (HR=2.02; 95% CI: 1.66 to 2.44), especially when performed at 18–29 years of age. The risk of CD was increased in the first 2 years, and decreased significantly after ≥15 years post appendectomy. Appendectomy appeared to protect against UC (HR=0.39; 95% CI: 0.22 to 0.71). The risk of UC was not associated with age at appendectomy, but decreased with time elapsed post appendectomy (HR=0.21; 95% CI: 0.06 to 0.72, comparing ≥5 with 0–4 years after appendectomy).

Conclusions

The increased risk of CD related to appendectomy in young adults may result from detection bias, but physicians should have a low threshold for suspicion of CD in young symptomatic adults with a history of appendectomy. A strong protective effect of appendectomy against UC was observed after 5 years.

The Role of Appendicectomy in Ulcerative Colitis: Systematic Review and Meta-Analysis

BACKGROUND

This updated systematic review and meta-analysis investigates the putative role of the appendix in ulcerative colitis as a therapeutic target.

METHODS

Ovid Medline, Embase, PubMed and CENTRAL were searched with MeSH terms ("appendectomy" OR "appendicitis" OR "appendix") AND ("colitis, ulcerative") through October 2020, producing 1469 references. Thirty studies, including 118 733 patients, were included for qualitative synthesis and 11 for quantitative synthesis. Subgroup analysis was performed on timing of appendicectomy. Results are expressed as odds ratio (OR) with 95% confidence intervals (CIs).

RESULTS

Appendicectomy before UC diagnosis reduces the risk of future colectomy (OR, 0.76; 95% CI, 0.65-0.89; I2 = 5%; P = .0009). Corresponding increased risk of colorectal cancer and high-grade dysplasia are identified (OR, 2.27; 95% CI, 1.11-4.66; P = .02). Significance is lost when appendicectomy is performed after disease onset. Appendicectomy does not affect hospital admission rates (OR, 0.87; 95% CI, 0.68-1.12; I2 = 93%; P = .27), steroid use (OR, 1.08; 95% CI, 0.78-1.49; I2 = 36%; P = .64), immunomodulator use (OR, 1.04; 95% CI, 0.76-1.42; I2 = 19%; P = .79), or biological therapy use (OR, 0.76; 95% CI, 0.44-1.30; I2 = 0%; P = .32). Disease extent and risk of proximal progression are unaffected by appendicectomy. The majority (71% to 100%) of patients with refractory UC avoid colectomy following therapeutic appendicectomy at 3-year follow-up.

CONCLUSIONS

Prior appendicectomy reduces risk of future colectomy. A reciprocal increased risk of CRC/HGD may be due to prolonged exposure to subclinical colonic inflammation. The results warrant further research, as consideration may be put toward incorporating a history of appendicectomy into IBD surveillance guidelines. A potential role for therapeutic appendicectomy in refractory left-sided UC is also identified.

Clinical relevance of endoscopic peri-appendiceal red patch in ulcerative colitis patients

BACKGROUND

Increasing evidence is suggesting appendectomy as an alternative treatment for ulcerative colitis (UC), especially in case of histological appendiceal inflammation. Therefore, preoperative identification of appendiceal inflammation could be beneficial. This study aimed to assess the prevalence of peri-appendiceal red patch (PARP) on colonoscopy. In addition, prognostic relevance of PARP for disease course and its predictive value for histological appendiceal inflammation in patients undergoing appendectomy was assessed.

METHODS

UC patients undergoing colonoscopy in 2014/2015 were included to determine PARP-prevalence in a cross-sectional study. Findings were correlated to patient and disease characteristics, upscaling of treatment and colectomy rates after cross-sectional colonoscopy. In patients undergoing appendiceal resection, histopathological inflammation was assessed using the Robarts Histopathology Index (RHI).

RESULTS

In total, 249 patients were included of which 17.7% (44/249) had a PARP. Patients with PARP were significantly younger with a shorter disease course. The majority of patients with PARP (61.4%) was in endoscopic remission. Patients with PARP required more upscaling of medical therapy (81.8% vs. 58.0%, p < 0.01), and more PARP patients underwent colectomy (13.6% vs. 4.9%, p = 0.04). Patients with PARP had a higher median RHI in resection specimens (14 vs. 7, p < 0.01).

CONCLUSION

PARP was present during colonoscopy regardless disease activity and was predominantly found in UC patients with younger age and shorter disease duration. PARP patients had a more severe course of UC, and in case of appendectomy, more severe histopathological appendiceal inflammation. Appendectomy as an experimental therapy for UC has been suggested to be predominantly effective in UC patients with appendiceal inflammation. This study demonstrates that presence of a PARP on colonoscopy predicts appendiceal inflammation. After consensus has been reached on the therapeutic effect of appendectomy, assessing PARP presence during colonoscopy could therefore contribute to identifying patients most likely to respond.

Environmental variables and genome-environment interactions predicting IBD diagnosis in large UK cohort

A combination of genetic susceptibility and environmental exposure is thought to cause inflammatory bowel disease (IBD), but the non-genetic component remains poorly characterized. We therefore undertook a search for environmental variables and gene-environment interactions associated with future IBD diagnosis in a large UK cohort. Using self-report and electronic health records, we identified 1946 Crohn's disease (CD) and 3715 ulcerative colitis (UC) patients after quality control in the UK Biobank. Based on prior literature and biological plausibility , we tested 38 candidate environmental variables for association with CD, UC, and overall IBD using Cox proportional hazard regressions. We also tested whether these variables interacted with polygenic risk in predicting disease, following up significant (FDR < 0.05) results with tests for SNP-environment associations. We performed robustness analyses on all significant results. As in previous reports, appendectomy protected against UC, smoking (both current and previous) elevated risk for CD, current smoking protected against UC, and previous smoking imparted a risk for UC. Childhood antibiotic use associated with IBD, as did sun exposure during the winter. Socioeconomic deprivation was conferred a risk for IBD, CD, and UC. We uncovered negative interactions between polygenic risk and previous oral contraceptive use for IBD and UC. Polygenic risk also interacted negatively with previous smoking in predicting UC. There were no individually significant SNP-environment interactions. Thus, for a limited set of environmental variables, there was strong evidence of association with IBD diagnosis in the UK Biobank, and interaction with polygenic risk was minimal.

Appendix and Ulcerative Colitis: a Key to Explaining the Pathogenesis and Directing Novel Therapies?

The vermiform appendix is generally considered a redundant organ, but recent evidence suggests that the appendix could contribute to the pathogenesis of inflammatory bowel diseases, in particular ulcerative colitis (UC), and may even have a therapeutic role; however, mechanisms of the appendix involvement remain unclear. Here, we highlight current evidence on the link between the appendix and UC and consider plausible therapeutic implications. A literature search was conducted using PubMed and PubMed Central from inception to Nov 2021 using the terms "Appendix", "UC", "Appendix & UC," "Appendectomy", and "Peri-appendicular patch," including only articles published in English. Reference lists from the selected studies were manually searched and reviewed to gather additional related reports. Inflammation around the appendix ("peri-appendicular patch") has been frequently observed in UC patients without other cecal involvement, and this inflammation can even precede the onset of UC. Epidemiologic studies propose that appendectomy reduces the risk of developing UC or even the risk of flare after UC is diagnosed, although this remains controversial. We reviewed studies showing altered host-microbe interactions in the appendix in UC, which suggest that the appendix could act as a priming site for disease via alterations in the immune response and changes in microbiota carried distally to the colon. In summary, recent literature suggests a possible role for microbes and immune cells within the appendix; however, the role of the appendix in the pathogenesis of UC remains unclear. Further research could clarify the therapeutic potential related to this organ.

Where Do We Stand in the Behavioral Pathogenesis of Inflammatory Bowel Disease? The Western Dietary Pattern and Microbiota-A Narrative Review

Despite the increasing knowledge with regard to IBD (inflammatory bowel disease), including ulcerative colitis (UC) and Crohn’s disease (CD), the etiology of these conditions is still not fully understood. Apart from immunological, environmental and nutritional factors, which have already been well documented, it is worthwhile to look at the possible impact of genetic factors, as well as the composition of the microbiota in patients suffering from IBD. New technologies in biochemistry allow to obtain information that can add to the current state of knowledge in IBD etiology.

Vermiform Appendix and the Potential for Missed Pathologies

Introduction

The appendix is considered an appendage of little value and is often treated disdainfully, be it as part of evolutionary process, on a grossing table, under a microscope or while archiving specimens and slides. It is only recently, with data indicating its importance in gut immunity and as the origin of pseudomyxoma, that its space in a human body appears vindicated.

Aim

Our aim was to screen the histopathologic spectrum of appendix lesions observed in our hospital for rare, incidental or clinico-radiologically uncertain lesions that would help emphasize a necessary seriousness in its sampling.

Method

All appendectomy specimens over ten years were screened for diagnosis other than acute/chronic/resolving appendicitis and pseudomyxoma peritonei. Among the recorded rare diagnoses, one representative case each, based on interesting history or pathology, was selected for discussion.

Observation

Forty-three lesions were found to meet inclusion criteria comprising 12 varied etiologies. Among these, 25 had a normal-appearing appendix and 27 were not suspected on radiology or on clinical/surgical assessment. Histopathology comprised, among others, neoplastic entities such as (Diffuse large B-cell) lymphoma, metastasis, carcinoid as well as interesting non-neoplastic diagnoses such as pinworm infestation (in the elderly) and (post-menopausal) endometriosis.

Conclusion

Sampling and histopathologic assessment of the appendix should be compulsory, careful and representative. Each specimen must be treated as harboring a potential pathology, until microscopically proven otherwise because missed “rare” diagnoses could delay therapy or alter key management decisions as cancer staging.

Appendiceal Orifice Inflammation Is Associated with Lower Rate of Complete Endoscopic Remission in Patients with Ulcerative Colitis

Appendiceal orifice inflammation (AOI) is commonly considered a skip lesion in ulcerative colitis (UC). However, the clinical significance of AOI in UC patients remains controversial. This study aimed to evaluate the clinical feature and long-term outcomes of AOI by comparing UC patients with and without AOI. This study was conducted as a retrospective design of patients who were newly diagnosed or referred within 3 months after diagnosis at Seoul St. Mary's Hospital from 1 January 2001 to 31 December 2020. All patients underwent index and follow-up colonoscopies. The long-term outcomes involved achieving complete endoscopic remission (ER), use of biologics, hospitalization, and proximal disease extension. Complete ER was defined as Mayo endoscopic subscore 0. In total, 318 UC patients were included, of which 140 had AOI. The baseline characteristics were not significantly different between AOI and non-AOI groups. The cumulative risk of complete ER was a significant difference between AOI and non-AOI groups (p = 0.041). The other cumulative risks of disease outcomes were not significantly different between AOI and non-AOI groups (use of biologics, p = 0.542; hospitalization, p = 0.795; proximal disease extension, p = 0.403). The multivariate Cox regression analysis also revealed that AOI was the significant factor of complete ER (hazard ratio, 0.656; 95% confidence interval, 0.462-0.932; p = 0.019) in UC patients. AOI shows a significant association with lower rate of complete ER in UC patients. Therefore, a meticulous treatment strategy may be recommended to achieve complete ER in UC patients with AOI.

Systematic review with meta-analysis: environmental and dietary differences of inflammatory bowel disease in Eastern and Western populations

BACKGROUND

While the incidence of inflammatory bowel disease (IBD) has stabilised in the West, it is still increasing in several newly industrialised countries.

AIMS

To investigate whether the environmental and dietary risk factors for IBD differ between Eastern and Western populations METHODS: We systematically searched PubMed, Embase, and Web of Science for studies published from inception through June 30, 2020. Data were pooled using a random effects model.

RESULTS

Overall, 255 studies were assessed. We identified 25 risk factors for IBD, seven of which were noted in both Eastern and Western populations: family history of Crohn's disease [CD] or ulcerative colitis [UC], former smoking (CD/UC), smoking (CD), appendicectomy (CD), tonsillectomy (CD), meat and meat products (CD), and vitamin D deficiency (UC). The remaining factors, including urban living, current smoking, antibiotics, oral contraceptives, caesarean section, isotretinoin, total energy, fat, cholesterol, fatty acids and their sub-classifications, eggs, and soft drinks, were associated with an increased risk of IBD in Western or Eastern populations only. We identified 21 protective factors for IBD, among which eight were common in the East and West: farm animals (CD/UC), Helicobacter pylori infection (CD/UC), multiple births (CD), physical activity (CD), history of breastfeeding (CD), pets (UC), current smoking (UC), and coffee intake (UC). Ten factors conferred protection against IBD in Western populations only, whereas eight factors conferred protection against IBD in Eastern populations only.

CONCLUSIONS

Numerous environmental and dietary factors influenced the development of IBD in both Western and Eastern populations, whereas certain factors influenced IBD risk differently in these populations.

When disease extent is not always a key parameter: Management of refractory ulcerative proctitis

Background

Patients with ulcerative proctitis represent a sub-group of ulcerative colitis patients with specific characteristics. Disease-related symptoms, endoscopic findings and patient's personality perspectives create a difficult-to-assess condition in certain cases.

Objectives

To summarize available evidence on the management of refractory ulcerative proctitis and provide insights in treatment options.

Results

/Conclusion: Topical therapy plays a central role due to the location of the disease. However, well-established treatment options may become exhausted in a considerable proportion of ulcerative proctitis patients, indicating the need to advance to more potent therapies in order to induce and maintain clinical response and remission in these refractory cases. Systemic corticosteroids, thiopurines, calcineurin inhibitors, biologic agents and small molecules have all been tested with variable success rates. Investigational interventions as well as surgical procedures are kept as the ultimate resort in multi-treatment resistant cases. Identifying early prognostic factors that herald a disabling disease progression will help in optimizing treatment and avoiding surgery.

Histologic Diagnosis of Inflammatory Bowel Diseases

Inflammatory bowel disease, including ulcerative colitis and Crohn disease, is an idiopathic chronic inflammatory condition of the gastrointestinal tract. Since neither the clinical manifestations nor the morphologic features of inflammatory bowel disease are pathognomonic alone, the differential diagnosis to consider is relatively broad, and it relies on the synthesis of clinical, endoscopic, and microscopic features. Long-held histologic diagnostic principles include recognizing structural and inflammatory features of chronicity, that is, architectural distortion, basal plasmacytosis, and expansion of the lamina propria lymphoplasmacytic infiltrate. In addition, evaluation of the neutrophilic inflammation and related crypt and epithelial destruction is essential to gauge the activity of the disease. Nevertheless, these features can be difficult to confirm in special settings, including at the inception of the disease or in partially treated cases. This review will explore the classic morphologic features of ulcerative colitis and Crohn disease, followed by a detailed discussion of atypical and diagnostically challenging presentations and a brief review of the clinical aspects necessary for the daily practice of pathologists.

An Evaluation of Serum IgE and Th2-Associated Interleukins in Children With Uncomplicated and Complicated Appendicitis

BACKGROUND

The pathogenesis of appendicitis is not understood completely and establishing a correct diagnosis can be clinically challenging. Previous investigations have shown an association between a T helper cell (Th)2-mediated inflammatory response, for example immunoglobulin E (IgE)-mediated allergy, and a decreased risk of complicated appendicitis. The present study aimed to evaluate differences in serum concentrations of IgE and Th2-associated interleukins (IL) in children with uncomplicated and complicated appendicitis.

METHOD

A prospective study including children <15 years with appendicitis. Blood samples were collected preoperatively at the time of clinical assessment at the Pediatric Emergency Department and analyzed for concentrations of serum total IgE and IL-4, IL-9, and IL-13. Associations with complicated appendicitis were evaluated through logistic regression adjusting for age, appendicolith, and symptom duration.

RESULTS

138 children with confirmed appendicitis were included. The median age was 10 (IQR 8-12) years, 87 (63%) were boys and 58 (42%) had complicated appendicitis. Children with complicated appendicitis had significantly higher concentrations of IL-9 and IL-13 compared to children with uncomplicated appendicitis. In the univariate logistic regression, high concentrations of IL-13 were associated with an increased risk of complicated appendicitis [OR 1.02 (95% CI 1.01-1.04) p = 0.005], which remained in the multivariate analysis [aOR 1.02 (95% CI 1.01-1.04), p = 0.01]. Serum concentrations of IgE, IL-4, and IL-9 did not significantly affect the risk of complicated appendicitis.

CONCLUSION

High levels of IL-13 seem to be associated with an increased risk of complicated appendicitis. This is incongruent with the hypothesis of an Th1/Th17-driven inflammation in this type of appendicitis.

High prevalence of ulcerative appendicitis in patients with ulcerative colitis

BACKGROUND

Previous studies have indicated that the appendix may be a priming site of ulcerative colitis (UC). Appendectomy is inversely associated with the development of UC, and is suggested to have a beneficial effect on the disease course in patients with refractory disease.

OBJECTIVE

The aim of the current study was to assess histological features of appendices from patients with UC and their clinical relevance.

METHODS

Patients with UC in remission and active UC (therapy refractory) that underwent appendectomy between 2012 and 2019 were included. Histological features of UC appendices were compared to those of patients with acute appendicitis and colon carcinoma. The Robarts Histopathology Index (RHI) was used to assess appendiceal inflammation. In patients with active UC, histological and clinical characteristics were compared between patients with and without endoscopic response following appendectomy.

RESULTS

In total, 140 appendix specimens were assessed (n = 35 UC remission, n = 35 active UC, n = 35 acute appendicitis, n = 35 colon carcinoma). Histological features of appendices from UC patients looked like UC rather than acute appendicitis. The presence of active appendiceal inflammation was comparable between patients in remission versus active disease (53.7% vs. 46.3%, p = 0.45) and limited versus extensive disease (58.5% vs. 41.5%, p = 0.50). Endoscopic response (Mayo 0-1) following appendectomy, assessed in 28 therapy refractory patients, was more frequently seen in patients with higher RHI scores (RHI > 6: 81.8% vs. RHI ≤ 6: 9.1%, p = 0.03) and limited disease (proctitis/left sided 63.6% vs. pancolitis 36.4%, p = 0.02).

CONCLUSION

The presence of active appendiceal inflammation is common in UC and does not correlate with colonic disease activity. More than 50% of UC patients in remission showed active histological disease in the appendix. Favorable response to appendectomy for refractory UC was seen in cases with ulcerative appendicitis. These findings might support the role of the appendix as a pivotal organ in UC.

Nationwide paediatric cohort study of a protective association between allergy and complicated appendicitis

BACKGROUND

In a nationwide cohort the potentially protective association between allergy and complicated appendicitis was analysed, and the influence of seasonal antigens, antihistamine treatment, and timing of allergy onset assessed.

METHODS

Some 1 112 571 children born between 2000 and 2010 were followed from birth until the end of 2014. A cross-sectional analysis of appendicitis cases, with comparison of allergic versus non-allergic children for absolute risk and odds of complicated appendicitis was first undertaken. This was followed by a longitudinal analysis of children with allergy and matched controls who had never had an allergy, for incidence rate and hazard of subsequent complicated or simple appendicitis.

RESULTS

Of all children, 20.4 per cent developed allergy and 0.6 per cent had appendicitis during follow-up. Among children with appendicitis, complicated appendicitis was more common among non-allergic children (18.9 per cent, 948 of 5016) than allergic children (12.8 per cent, 173 of 1351) (P < 0.001), and allergic children had a lower adjusted odds of complicated appendicitis (adjusted odds ratio (OR) 0.80, 95 per cent c.i. 0.67 to 0.96; P = 0.021). The risk of complicated appendicitis among children with manifest allergy was reduced by one-third in the longitudinal analysis (incidence rate 0.13 versus 0.20 per 1000 person-years; hazard ratio (HR) 0.68, 95 per cent c.i. 0.58 to 0.81; P < 0.001), whereas the risk of simple appendicitis remained unchanged (incidence rate 0.91 versus 0.91; HR 1.00, 0.94 to 1.07; P = 0.932). Seasonal antigen exposure was a protective factor (adjusted OR 0.82, 0.71 to 0.94; P = 0.004) and ongoing antihistamine medication a risk factor (adjusted OR 2.28, 1.21 to 4.28; P = 0.012).

CONCLUSION

Children with allergy have a lower risk of complicated appendicitis, but the same overall risk of simple appendicitis. Seasonal antigen exposure reduced, and antihistamine treatment increased, the risk of complicated disease.

Appendiceal inflammation in colectomy is independently correlated with early pouchitis following ileal pouch anal anastomosis in ulcerative colitis and indeterminate colitis

BACKGROUND

Appendiceal inflammation in colectomy is one of the histologic predictors of pouchitis in ulcerative colitis (UC) following ileal pouch anal anastomosis (IPAA). Fecal calprotectin level has been shown to increase 2 months prior to the onset of pouchitis. We evaluated whether inflammation and calprotectin expression in appendiceal specimens correlate with early-onset pouchitis in UC and indeterminate colitis (IC).

MATERIALS AND METHODS

IPAA (2000-2018) cases with appendix blocks available in colectomy specimens were identified (n = 93, 90 UC, 3 IC). Histologic features thought to predict pouchitis were evaluated. The degree of appendiceal inflammation was scored. Calprotectin immunostain was performed on the appendix blocks and the extent of mucosal staining was quantified. Electronic medical records were reviewed for demographics, smoking history, clinical pouchitis, time of onset of pouchitis, and clinical and endoscopic components of the Pouchitis Disease Activity Index (PDAI) score. Follow-up pouch biopsies were reviewed and scored to generate histologic PDAI score, when available.

RESULTS

Among the patients with clinical pouchitis (n = 73), moderate to severe appendiceal inflammation independently correlated with earlier pouchitis compared to no/mild inflammation (median time to pouchitis 12.0 vs. 23.8, log rank p = 0.016). Calprotectin staining correlated with inflammatory scores of the appendix (Spearman's rho, r = 0.630, p < 0.001) but not with early pouchitis (p > 0.05).

CONCLUSIONS

The presence of moderate to severe appendiceal inflammation at the time of colectomy was associated with a shorter time to pouchitis following IPAA. Calprotectin immunostain may be used to demonstrate the presence of inflammation in the appendix but its role in predicting early pouchitis remains limited.

State-of-the-art surgery for ulcerative colitis

Ulcerative colitis (UC) is an autoimmune-mediated colitis which can present in varying degrees of severity and increases the individual’s risk of developing colon cancer. While first-line treatment for UC is medical management, surgical treatment may be necessary in up to 25–30% of patients. With an increasing armamentarium of biologic therapies, patients are presenting for surgery much later in their course, and careful understanding of the complex interplay of the disease, its management, and the patient’s overall health is necessary when considering he appropriate way in which to address their disease surgically. Surgery is generally a total proctocolectomy either with pelvic pouch reconstruction or permanent ileostomy; however, this may need to be spread across multiple procedures given the complexity of the surgery weighed against the overall state of the patient’s health. Minimally invasive surgery, employing either laparoscopic, robotic, or transanal laparoscopic approaches, is currently the preferred approach in the elective setting. There is also some emerging evidence that appendectomy may delay the progression of UC in some individuals. Those who treat these patients surgically must also be familiar with the numerous potential pitfalls of surgical intervention and have plans in place for managing problems such as pouchitis, cuffitis, and anastomotic complications.

Long-term impacts of appendectomy associated with increased incidence of inflammatory bowel disease, infection, and colorectal cancer

PURPOSE

Although the appendix has been suggested to play a role in maintaining the gut microbiome and immune system, the ramifications of appendectomy on the development inflammatory bowel disease, sepsis, and colorectal cancer are yet to be determined. The purpose of this study was to evaluate the potential long-term impacts of appendectomy, with a focus on inflammatory bowel disease, infection, and colorectal cancer, using the National Healthcare Insurance Service (NHIS) database of Korea.

METHODS

The National Healthcare Insurance Service database in Korea was used for analysis. Adult patients who received appendectomy between 2005 and 2013 were identified. The control group consisted of patients who did not receive appendectomy were matched by baseline characteristics including comorbidities and frequency of healthcare resource utilization. The primary outcome was the incidence-rate ratio (IRR) of Crohn's disease, ulcerative colitis, Clostridium difficile infection, sepsis, and colorectal cancer after appendectomy or the index date.

RESULTS

We identified 914,208 patients who underwent appendectomy, and after matching with control patients, a total of 486,844 patients were included for analysis. Patients who underwent appendectomy showed a significantly higher incidence of Crohn's disease (IRR 4.40, 95% confidence interval (CI) 3.78-5.13) and ulcerative colitis (IRR 1.78, 95% CI 1.63-1.93) compared to the control group during the 5-year follow-up period. The associations between appendectomy and Clostridium difficile infection, sepsis, and colorectal cancer were all found to be significant.

CONCLUSION

Patients who underwent appendectomy may be at increased risk for developing Crohn's disease, ulcerative colitis, Clostridium difficile infection, sepsis, and colorectal cancer.

Associations of hair cortisol concentrations with paediatric appendicitis

The pathogenesis of paediatric appendicitis is still an enigma. In recent years, it has become more evident that our inherent immunological responses affect the trajectory of the disease course. Long-term stress has an impact on our immune system; however, it is practically and ethically challenging to prospectively track blood measurements of cortisol-levels in asymptomatic children should an acute appendicitis episode develop. The aim of this case–control study was therefore to evaluate the effect of increased stress measured as historical imprints in hair (hair cortisol concentrations [HCC]), on the risk of developing appendicitis and complicated appendicitis. 51 children (aged < 15 years) with appendicitis (34 with complicated appendicitis), were compared to 86 healthy controls. HCC reflecting the activity of the HPA-axis 0–3 and 4–6 months prior to sampling was evaluated and compared between groups as well as between the two measurements of each study subject. In the univariate analysis with both cases and controls, an increase in HCC between the measurement timepoints was associated with a substantial increase in risk of appendicitis (OR 7.52 [95% CI 2.49–22.67], p = 0.001). This increased risk remained in the multivariate analysis after adjustment for age, sex and season (aOR OR 10.76 [95%CI 2.50–46.28], p  = 0.001). When comparing the cases of uncomplicated and complicated appendicitis through a multivariate analysis, adjusted for age and sex, the children with an increased HCC prior to appendicitis had a substantial and statistically significant increase in risk of complicated appendicitis (aOR 7.86 [95% CI 1.20–51.63], p = 0.03). Biological stress, measured as an increase in HCC, seems to be associated with an increased risk of paediatric appendicitis and a more complicated disease course.

Interfering With Inflammation: Heterogeneous Effects of Interferons in Graft-Versus-Host Disease of the Gastrointestinal Tract and Inflammatory Bowel Disease

The intestine can be the target of several immunologically mediated diseases, including graft-versus-host disease (GVHD) and inflammatory bowel disease (IBD). GVHD is a life-threatening complication that occurs after allogeneic hematopoietic stem cell transplantation. Involvement of the gastrointestinal tract is associated with a particularly high mortality. GVHD development starts with the recognition of allo-antigens in the recipient by the donor immune system, which elicits immune-mediated damage of otherwise healthy tissues. IBD describes a group of immunologically mediated chronic inflammatory diseases of the intestine. Several aspects, including genetic predisposition and immune dysregulation, are responsible for the development of IBD, with Crohn’s disease and ulcerative colitis being the two most common variants. GVHD and IBD share multiple key features of their onset and development, including intestinal tissue damage and loss of intestinal barrier function. A further common feature in the pathophysiology of both diseases is the involvement of cytokines such as type I and II interferons (IFNs), amongst others. IFNs are a family of protein mediators produced as a part of the inflammatory response, typically to pathogens or malignant cells. Diverse, and partially paradoxical, effects have been described for IFNs in GVHD and IBD. This review summarizes current knowledge on the role of type I, II and III IFNs, including basic concepts and controversies about their functions in the context of GVHD and IBD. In addition, therapeutic options, research developments and remaining open questions are addressed.

Risk of Inflammatory Bowel Disease Following Appendectomy in Adulthood

Background: The appendix has a complicated immune function, and appendectomy may derange the immune system. Studies on the relationship between appendectomy and subsequent inflammatory bowel disease (IBD) have been inconsistent. We conducted a nationwide cohort study consisting of individuals who underwent appendectomy to evaluate the incidence and risk of ulcerative colitis (UC) and Crohn's disease (CD).

Methods: We identified patients aged >20 years who underwent appendectomy between 2000 and 2012 from inpatient claims of the National Health Insurance Research Database (NHIRD) and assigned them to the appendectomy cohort. Then, we randomly selected patients without appendectomy in the NHIRD and assigned them to the comparison cohort in a frequency-matched 1:1 ratio based on sex, age, and index year. We tracked down all participants until IBD diagnosis, death, or the end of 2013. Cox models were used to estimate the hazard ratio (HR), and 95% confidence intervals (CIs) were used to compare the IBD risk between the appendectomy and comparison cohorts.

Results: The appendectomy and comparison cohorts in the study consisted of 246 562 patients each. The appendectomy cohort exhibited a 2.23- and 3.48-fold higher risk of UC (adjusted HR = 2.23, 95% CI = 1.59-3.12) and CD (adjusted HR = 3.48, 95% CI = 2.42-4.99), respectively, than did the comparison cohort. UC and CD risks significantly increased in the appendectomy cohort regardless of whether appendicitis was present.

Conclusions: Our study suggests that appendectomy increases UC and CD risks irrespective of appendicitis.

Long-term effects of appendectomy in humans: is it the optimal management of appendicitis?

INTRODUCTION

Appendectomy remains the gold standard for treating uncomplicated and complicated appendicitis. However, the vermiform appendix may play a significant role in the immune system (secondary immune function) and maintain a reservoir of the normal microbiome for the human body. The aim of this study was to summarize the long-term effects after appendectomy and discuss whether appendectomy is suitable for all appendicitis patients.

AREAS COVERED

A comprehensive and unbiased literature search was performed in PubMed. The terms 'appendix,' 'appendicitis,' 'appendectomy,' and 'endoscopic retrograde appendicitis therapy' were searched in the title and/or abstract. This review summarizes the long-term effects of appendectomy on some diseases in humans and describes three methods including appendectomy, medical treatment, and an 'organ-sparing' technique, named endoscopic retrograde appendicitis therapy (ERAT) to treat appendicitis.

EXPERT OPINION

Appendectomy remains the first-line therapy for appendicitis. The patient's problem is appendix, not appendicitis. If we treat appendicitis, the problem should be resolved. During COVID-19, an initial antibiotic treatment of mild appendicitis represents a promising strategy. For patients who are worried about the long-term adverse effect after appendectomy and have a strong desire to preserve the appendix and are aware of the risk of appendicitis recurrence, medical treatment, or ERAT could be proposed.

A Review of Inflammatory Bowel Disease: A Model of Microbial, Immune and Neuropsychological Integration

Objective: Inflammatory bowel diseases (IBDs) are complex chronic inflammatory disorders of the gastro-intestinal (GI) tract with uncertain etiology. IBDs comprise two idiopathic disorders: Crohn's disease (CD) and ulcerative colitis (UC). The aetiology, severity and progression of such disorders are still poorly understood but thought to be influenced by multiple factors (including genetic, environmental, immunological, physiological, psychological factors and gut microbiome) and their interactions. The overarching aim of this review is to evaluate the extent and nature of the interrelationship between these factors with the disease course. A broader conceptual and longitudinal framework of possible neuro-visceral integration, core microbiome analysis and immune modulation assessment may be useful in accurately documenting and characterizing the nature and temporal continuity of crosstalk between these factors and the role of their interaction (s) in IBD disease activity. Characterization of these interactions holds the promise of identifying novel diagnostic, interventions, and therapeutic strategies. Material and Methods: A search of published literature was conducted by exploring PubMed, EMBASE, MEDLINE, Medline Plus, CDSR library databases. Following search terms relating to key question were set for the search included: "Inflammatory bowel diseases," "gut microbiota," "psychological distress and IBD," "autonomic reactivity and IBD," "immune modulation," "chronic inflammation," "gut inflammation," "enteric nervous system," "gut nervous system," "Crohn's disease," "Ulcerative colitis", "depression and IBD", "anxiety and IBD", "quality of life in IBD patients," "relapse in IBDs," "remission in IBDs," "IBD disease activity," "brain-gut-axis," "microbial signature in IBD," "validated questionnaires in IBD," "IBD activity indices," "IBD aetiology," "IBDs and stress," "epidemiology of IBDs", "autonomic nervous system and gut inflammation", "IBD and environment," "genetics of IBDs," "pathways of immune response in IBDs," "sleep disturbances in IBD," "hypothalamic-pituitary-adrenal axis (HPA)," "sympatho-adrenal axis," "CNS and its control of gut function" "mucosal immune response," "commensal and pathogenic bacteria in the gut," "innate and adaptive immunity." Studies evaluating any possible associations between gut microbiome, psychological state, immune modulation, and autonomic function with IBDs were identified. Commonly cited published literatures with high quality research methodology/results and additional articles from bibliographies of recovered papers were examined and included where relevant. Results: Although there is a substantial literature identifying major contributing factors with IBD, there has been little attempt to integrate some factors over time and assess their interplay and relationship with IBD disease activity. Such contributing factors include genetic and environmental factors, gut microbiota composition and function, physiological factors, psychological state and gut immune response. Interdependences are evident across psychological and biological factors and IBD disease activity. Although from the available evidence, it is implausible that a single explanatory model could elucidate the interplay between such factors and the disease course as well as the sequence of the effect during the pathophysiology of IBD. Conclusion: Longitudinal monitoring of IBD patients and integrating data related to the contributing/risk factors including psychological state, physiological conditions, inflammatory/immune modulations, and microbiome composition/function, could help to explain how major factors associate and interrelate leading to exacerbation of symptoms and disease activity. Identifying the temporal trajectory of biological and psychosocial disturbances may also help to assess their effects and interdependence on individuals' disease status. Moreover, this allows greater insight into understanding the temporal progressions of subclinical events as potential ground for disease severity in IBD. Furthermore, understanding the interaction between these risk factors may help better interventions in controlling the disease, reducing the costs related to disease management, further implications for clinical practice and research approaches in addition to improving patients' mental health and quality of life.

Epidemiology, burden of disease, and unmet needs in the treatment of ulcerative colitis in Asia

INTRODUCTION

Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disease of the colon, characterized by relapsing and remitting symptoms. Although traditionally viewed as a Western disease, the incidence and prevalence of UC is increasing in developing regions, including Asian countries.

AREAS COVERED

A PubMed search identified articles describing epidemiology, disease burden, patient demographics, clinical characteristics, risk factors, and treatment of UC across Asia. We review the epidemiology and disease course of UC across Asia, including region-specific factors that may aid development of more cost-effective treatment approaches tailored to the needs of Asian populations.

EXPERT OPINION

The opinion of non-Pfizer-affiliated practicing gastroenterologists is that epidemiological data from the last four decades have shown 1.5-fold to almost 20-fold increases in the incidence and prevalence of UC in some Asian countries, although prevalence remains generally lower than in the West. As the prevalence of UC rises, so will overall healthcare costs. Disparities in healthcare systems and funding mean that different Asian countries face unique challenges in how best to use available resources, including selection from a growing number of emerging treatment options. More clinical trial and real-world data are required to help define treatment approaches that will most benefit Asian populations.

Impact of Appendectomy on Gut Microbiota

Background: Considered vestigial from the classic point of view, the vermiform appendix has long been the subject of intensive studies. The recent understanding of appendix function in the context of unique architecture and bacterial complexity and density allows considering it as a safehouse for intestinal biodiversity. Methods: This review analyzes and assesses the current state of scientific knowledge regarding the role of the vermiform appendix in normal gut microbiota maintenance as a crucial factor of host homeostasis. It also highlights the difference in microbial composition between the large bowel and the appendix, as well as the association between the surgical excision, appendectomy, and dysbiosis-induced diseases. In addition, the review discusses the results of epidemiologic studies on appendectomy as a risk factor for the initiation of gastrointestinal carcinogenesis. It also highlights the association between appendectomy and a series of chronic inflammatory and neurologic disorders, including inflammatory bowel disease.

Appendectomy Does Not Increase the Risk of Future Emergence of Parkinson's Disease: A Meta-analysis

OBJECTIVE

To explore the impact of appendectomy history on emergence of Parkinson's disease (PD).

BACKGROUND

Although there are several studies to investigate the relationship between appendectomy history and emergence of PD, the results are still controversial.

METHODS

We performed a comprehensive electronic search of the literature (the Cochrane Library, PubMed, and the Web of Science) up to April 2020 to identify studies that had employed databases allowing comparison of emergence of PD between patients with and those without appendectomy history. To integrate the impact of appendectomy history on emergence of PD, a meta-analysis was performed using random-effects models to calculate the risk ratio (RR) and 95% confidence interval (CI) for the selected studies, and heterogeneity was analyzed using I² statistics.

RESULTS

Four studies involving a total of 6 080 710 patients were included in this meta-analysis. Among 1 470 613 patients with appendectomy history, 1845 (.13%) had emergences of PD during the observation period, whereas among 4 610 097 patients without appendectomy history, 6743 (.15%) had emergences of PD during the observation period. These results revealed that patients with appendectomy history and without appendectomy had almost the same emergence of PD (RR, 1.02; 95% CI, .87-1.20; P = .83; I² = 87%).

CONCLUSION

This meta-analysis has demonstrated that there was no significant difference in emergence of PD between patients with and those without appendectomy history.

A nationwide database study on colectomy and colorectal cancer in ulcerative colitis: what is the role of appendectomy?

AIM

Although has been suggested that an appendectomy has a positive effect on the disease course in patients with ulcerative colitis (UC), recent studies indicate a potential increase in risk of colectomy and colorectal cancer (CRC). This study aimed to evaluate the rates of colectomy and CRC after appendectomy in UC patients using a nationwide prospective database [the Initiative on Crohn and Colitis Parelsnoer Institute - Inflammatory Bowel Disease (ICC PSI-IBD) database].

METHOD

All UC patients were retrieved from the ICC PSI-IBD database between January 2007 and May 2018. Primary outcomes were colectomy and CRC. Outcomes were compared in patients with and without appendectomy, with a separate analysis for timing of appendectomy (before or after UC diagnosis).

RESULTS

A total of 826 UC patients (54.7% female; median age 46 years, range 18-89 years) were included. Sixty-three (7.6%) patients had previously undergone appendectomy: 24 (38.1%) before and 33 (52.4%) after their diagnosis of UC. In multivariate analysis, appendectomy after UC diagnosis was associated with a significantly lower colectomy rate compared with no appendectomy [hazard ratio (HR) 0.16, 95% C: 0.04-0.66, P = 0.011], and the same nonsignificant trend was seen in patients with an appendectomy before UC diagnosis (HR 0.35, 95% CI 0.08-1.41, P = 0.138). Appendectomy was associated with delayed colectomy, particularly when it was performed after diagnosis of UC (P = 0.009). No significant differences were found in the CRC rate between patients with and without appendectomy (1.6% vs 1.2%; P = 0.555).

CONCLUSION

Appendectomy in established UC is associated with an 84% decreased risk of colectomy and a delay in surgery. Since the colon is in situ for longer, the risk of developing CRC remains, which underscores the importance of endoscopic surveillance programmes.

Epidemiology and Pathogenesis of Ulcerative Colitis

Ulcerative colitis (UC) is a complex chronic, immune-mediated inflammatory disorder of the colon. Factors associated with increased risk of UC include diet, particularly Western diet influences in newly industrialized nations, medications, and lifestyle factors that may influence the host's microbiome or immune response to antigens. Although much evidence identifying potential genetic and host-related factors is currently available, there are still many unanswered questions. As the global UC incidence and prevalence continues to increase, there are multiple opportunities for continued investigation to clarify our understanding of UC, identify potential predictors of disease severity, response to therapy, and novel therapeutic targets.