The TNFSF15 gene single nucleotide polymorphism rs7848647 is associated with surgical diverticulitis

Genetic, epigenetic and environmental factors in diverticular disease: systematic review

BACKGROUND

Diverticulosis is a normal anatomical variant of the colon present in more than 70% of the westernized population over the age of 80. Approximately 3% will develop diverticulitis in their lifetime. Many patients present emergently, suffer high morbidity rates and require substantial healthcare resources. Diverticulosis is the most common finding at colonoscopy and has the potential for causing a significant morbidity rate and burden on healthcare. There is a need to better understand the aetiology and pathogenesis of diverticular disease. Research suggests a genetic susceptibility of 40-50% in the formation of diverticular disease. The aim of this review is to present the hypothesized functional effects of the identified gene loci and environmental factors.

METHODS

A systematic literature review was performed using PubMed, MEDLINE and Embase. Medical subject headings terms used were: 'diverticular disease, diverticulosis, diverticulitis, genomics, genetics and epigenetics'. A review of grey literature identified environmental factors.

RESULTS

Of 995 articles identified, 59 articles met the inclusion criteria. Age, obesity and smoking are strongly associated environmental risk factors. Intrinsic factors of the colonic wall are associated with the presence of diverticula. Genetic pathways of interest and environmental risk factors were identified. The COLQ, FAM155A, PHGR1, ARHGAP15, S100A10, and TNFSF15 genes are the strongest candidates for further research.

CONCLUSION

There is increasing evidence to support the role of genomics in the spectrum of diverticular disease. Genomic, epigenetic and omic research with demographic context will help improve the understanding and management of this complex disease.

Diverticulitis Familiality: A Statewide Case-Control Study

BACKGROUND

The etiology of diverticulitis is multifactorial and poorly understood. We estimated the familiality of diverticulitis using the Utah Population Database, a statewide database linking medical records with genealogy data.

STUDY DESIGN

We identified patients with diverticulitis diagnosed between 1998 and 2018 and age- and sex-matched controls in the Utah Population Database. Risk of diverticulitis in family members of patients and controls was calculated using multivariable Poisson models. We performed exploratory analyses to determine the association of familial diverticulitis with severity of disease and age of onset.

RESULTS

The study population included 9,563 diverticulitis patients (with 229,647 relatives) and 10,588 controls (with 265,693 relatives). Relatives of patients were more likely to develop diverticulitis (incidence rate ratio [IRR] 1.5, 95% CI 1.4 to 1.6) compared with relatives of controls. There was an elevated risk of diverticulitis among first-degree (IRR 2.6, 95% CI 2.3 to 3.0), second-degree (IRR 1.5, 95% CI 1.3 to 1.6), and third-degree relatives of patients (IRR 1.3, 95% CI 1.2 to 1.4). Complicated diverticulitis was more common among relatives of patients compared with relatives of controls (IRR 1.6, 95% CI 1.4 to 1.8). Age at diverticulitis diagnosis was similar between groups (relatives of patients 0.2 years older than relatives of controls, 95% CI -0.5 to 0.9).

CONCLUSIONS

Our results indicate that the first-, second-, and third-degree relatives of diverticulitis patients are at elevated risk of developing diverticulitis. This information may aid surgeons in counseling patients and family members about diverticulitis risk and can inform the development of future risk-stratification tools. Further work is needed to clarify the causal role and relative contribution of various genetic, lifestyle, and environmental factors in the development of diverticulitis.

Creating a Surgical Biobank: The Hershey Medical Center Experience

BACKGROUND

Tissue harvesting at the time of surgery offers surgeons and scientists a unique opportunity to discover and better understand disease pathophysiology. Tissue biobanking presents challenges in patient consents, specimen collection, preparation, and storage, but the potential for scientific discovery justifies the effort. Although the number of tissue biobanks is increasing worldwide, information regarding necessary infrastructure, process flow, and management of expected obstacles is lacking.

OBJECTIVE

To provide a framework and motivation for clinician scientists intending to start an intestinal tissue biobank under their direction.

DATA SOURCES

The Carlino Family Inflammatory Bowel and Colorectal Diseases Biobank is housed at the Milton S. Hershey Medical Center.

STUDY SELECTION

Review.

INTERVENTION

Implementation of a surgical tissue biobank at a large tertiary care institution.

MAIN OUTCOME MEASURES

Assess critical challenges and obstacles over the years as well as keys to the success of the program.

RESULTS

Over 2 decades, the institutional biobank grew from an IBD biobank to one which now incorporates thousands of surgical specimens representing numerous colorectal diseases. This was done through a process of refinement focusing on patient recruitment and an efficient consenting and specimen management process. The biobank's success is further insured by institutional, external, and philanthropic support; scientific collaborations; and sharing of biological specimens with other groups of dedicated researchers.

LIMITATIONS

This is a single-center experience in collecting surgically resected colorectal specimens.

CONCLUSIONS

Surgical specimen biobanks are essential in studying disease cause using genomics, transcriptomics, and proteomic technologies. Therefore, surgeons, clinicians, and scientists should build biobanks at their institutions to promote further scientific discovery and improve specimen diversity.

Diverticulosis and Diverticulitis: Epidemiology, Pathophysiology, and Current Treatment Trends

Diverticular disease is a common surgical condition, especially in the Western world. Its existence is well known in Asian countries as well; however, its impact on Asian health care is not the same as that in Western countries. Diverticular disease has a variable presentation, and its implications can be challenging to manage both for the patient and the medical professionals. Diet and lifestyle are commonly associated with its etiology. In Western countries, much attention is given to diverticular disease, and with the acceptance of colonoscopy as a surveillance investigation, a greater number of people are diagnosed with diverticular disease at an early stage and overall. In acute presentations, a CT scan of the abdomen remains the investigation of choice. The most common presentation of diverticular disease is pain in the abdomen or a change in bowel habits. In most cases, diverticular disease is treated with medical intervention; however, in cases associated with severe complications or advanced stages, surgical modality remains the primary treatment.

Surgery for young onset diverticulitis: is it curative?

PURPOSE

Previously considered a disease of old age, diverticular disease is increasingly prevalent in younger populations. Guidelines on surgical resection have shifted from recommending resection for all young onset patients to an individualized approach. Therefore, we aim to determine demographics and outcomes including radiographic and surgical recurrence rates in patients < 40 years old undergoing resection for diverticular disease.

METHODS

A retrospective, single center study was performed. All patients ≤ 39 years undergoing operative intervention for left-sided diverticular disease between Jan 2010 and July 2017 were included. Recurrence was determined by individual review of imaging and operative reports.

RESULTS

Overall, 147 (n = 107/72.8% male, mean age = 34.93 ± 4.12 years) patients were included. The majority were ASA 1 or 2 (n = 41/27.9% and n = 82/55.8%). The most common surgical indication was uncomplicated diverticulitis (n = 77, 52.4%) followed by perforation (n = 26/17.7%). The majority (n = 108/73.5%) of cases were elective. Seventy-nine (57.3%) of all cases were performed laparoscopically. Primary anastomosis without diversion was the most common surgical outcome (n = 108/73.5%). Median length of stay was 5 (4, 7) days. There was no mortality. There were three (2.0%) intraoperative and 38 (25.9%) postoperative complications. The most common complication was anastomotic leak (n = 6/4.1%). The majority (n = 5) of leaks occurred after elective surgery. Two neoplastic lesions (1.3% of cohort) were found (1 adenoma with low-grade dysplasia/1 polyp cancer). Over a mean follow-up of 96 (74, 123) months, only 2 (1.3%) patients experienced a surgical or radiological recurrence.

CONCLUSION

Both neoplasia and recurrence after resection for diverticular disease in young onset patients are rare. Leaks after primary anastomosis even in the elective setting warrant careful consideration of a defunctioning ileostomy.

The Association Between Family History and Diverticulitis Recurrence: A Population-Based Study

BACKGROUND

After initial nonoperative management of diverticulitis, individuals with a family history of diverticulitis may have increased risk of recurrent disease.

OBJECTIVE

This study measured the association between family history and recurrent diverticulitis in a population-based cohort.

DESIGN

This is a retrospective, population-based cohort study.

SETTINGS

The cohort was identified from the Utah Population Database, a statewide resource linking hospital and genealogy records.

PATIENTS

Individuals evaluated in an emergency department or hospitalized between 1998 and 2018 for nonoperatively managed diverticulitis were included.

INTERVENTION

The primary predictor was a positive family history of diverticulitis, defined as diverticulitis in a first-, second-, or third-degree relative.

MAIN OUTCOME MEASURES

This study measured the adjusted association between family history and the primary outcome of recurrent diverticulitis. A secondary outcome was elective surgery for diverticulitis. Additional analyses evaluated risk by degree of relation of the affected family member.

RESULTS

The cohort included 4426 individuals followed for a median of 71 months. Median age was 64 years and 45% were male; 17% had complicated disease, 11% had recurrence, and 15% underwent elective surgery. After adjustment, individuals with a family history of diverticulitis had a similar risk of recurrence when compared to those without a family history (HR 1.0; 95% CI 0.8-1.2). However, individuals with a family history of diverticulitis were more likely to undergo elective surgery (HR 1.4; 95% CI 1.1-1.6). This effect was most pronounced in those with an affected first-degree family member (HR 1.7; 95% CI 1.4-2.2).

LIMITATIONS

The use of state-specific data may limit generalizability.

CONCLUSIONS

In this population-based analysis, individuals with a family history of diverticulitis were more likely to undergo elective surgery than those without a family history, despite similar risks of recurrence and complicated diverticulitis. Further work is necessary to understand the complex social, environmental, and genetic factors that influence diverticulitis treatment and outcomes. See Video Abstract at http://links.lww.com/DCR/B876 .

ASOCIACIN ENTRE LOS ANTECEDENTES FAMILIARES Y LA RECURRENCIA DE LA DIVERTICULITIS UN ESTUDIO POBLACIONAL

ANTECEDENTES:Después del tratamiento inicial no quirúrgico de la diverticulitis, las personas con antecedentes familiares de diverticulitis pueden tener un mayor riesgo de enfermedad recurrente.OBJETIVO:Este estudio midió la asociación entre antecedentes familiares y diverticulitis recurrente en una cohorte poblacional.DISEÑO:Este es un estudio de cohorte retrospectivo de la población.ENTORNO CLÍNICO:La cohorte se identificó a partir de la Base de datos de población de Utah, un recurso estatal que vincula los registros hospitalarios y genealógicos.PACIENTES:Se incluyeron individuos evaluados en un departamento de emergencias u hospitalizados entre 1998 y 2018 por diverticulitis manejada de forma no quirúrgica.INTERVENCIÓN:El predictor principal fue un historial familiar positivo de diverticulitis, definida como diverticulitis en un familiar de primer, segundo o tercer grado.PRINCIPALES MEDIDAS DE VALORACIÓN:Este estudio midió la asociación ajustada entre los antecedentes familiares y el resultado primario de diverticulitis recurrente. Un resultado secundario fue la cirugía electiva por diverticulitis. Análisis adicionales evaluaron el riesgo por grado de parentesco del familiar afectado.RESULTADOS:La cohorte incluyó a 4.426 individuos seguidos durante una mediana de 71 meses. La mediana de edad fue de 64 años y el 45% eran varones. El 17% tenía enfermedad complicada, el 11% recidiva y el 15% se sometió a cirugía electiva. Después del ajuste, los individuos con antecedentes familiares de diverticulitis tenían un riesgo similar de recurrencia en comparación con aquellos sin antecedentes familiares (HR 1,0; IC del 95%: 0,8-1,2). Sin embargo, las personas con antecedentes familiares de diverticulitis tenían más probabilidades de someterse a una cirugía electiva (HR 1,4; IC del 95%: 1,1-1,6). Este efecto fue más pronunciado en aquellos con un familiar de primer grado afectado (HR 1,7; IC del 95%: 1,4-2,2).LIMITACIONES:El uso de datos específicos del estado puede limitar la generalización.CONCLUSIONES:En este análisis poblacional, los individuos con antecedentes familiares de diverticulitis tenían más probabilidades de someterse a una cirugía electiva que aquellos sin antecedentes familiares, a pesar de riesgos similares de recurrencia y diverticulitis complicada. Es necesario seguir trabajando para comprender los complejos factores sociales, ambientales y genéticos que influyen en el tratamiento y los resultados de la diverticulitis. Consulte Video Resumen en http://links.lww.com/DCR/B876 . (Traducción-Dr. Ingrid Melo ).

Pathophysiology of Diverticular Disease: From Diverticula Formation to Symptom Generation

Diverticular disease is a common clinical problem, particularly in industrialized countries. In most cases, colonic diverticula remain asymptomatic throughout life and sometimes are found incidentally during colonic imaging in colorectal cancer screening programs in otherwise healthy subjects. Nonetheless, roughly 25% of patients bearing colonic diverticula develop clinical manifestations. Abdominal symptoms associated with diverticula in the absence of inflammation or complications are termed symptomatic uncomplicated diverticular disease (SUDD). The pathophysiology of diverticular disease as well as the mechanisms involved in the shift from an asymptomatic condition to a symptomatic one is still poorly understood. It is accepted that both genetic factors and environment, as well as intestinal microenvironment alterations, have a role in diverticula development and in the different phenotypic expressions of diverticular disease. In the present review, we will summarize the up-to-date knowledge on the pathophysiology of diverticula and their different clinical setting, including diverticulosis and SUDD.

Acute Diverticulitis in Young Patients: A Review of the Changing Epidemiology and Etiology

Acute diverticulitis is one of the leading gastrointestinal causes for hospitalization. The incidence of acute diverticulitis has been increasing in recent years, especially in patients under 50 years old. Historically, acute diverticulitis in younger patients was felt to represent a separate entity, being more virulent and associated with a higher rate of recurrence. Accordingly, young patients were often managed differently to older counterparts. Our understanding of the natural history of this condition has evolved, and current clinical practice guidelines suggest age should not alter management. The purpose of this review is to evaluate the changing epidemiology of acute diverticulitis, consider potential explanations for the observed increased incidence in younger patients, as well as review the natural history of acute diverticulitis in the younger population.

Emerging evidence and recent controversies in diverticulitis: a 5-year review

Diverticulitis is a common gastrointestinal disease that still garners significant attention and study because of its heterogeneity in presentation and outcome. We provide a review of the newest and most controversial topics in diverticulitis. Recent discoveries on the influence of diet and other environmental risk factors are discussed, showing how the epidemiology of the disease process is shifting away from what was previously felt to be a disorder primarily limited to older western populations. Interestingly, as has long been suspected, genetic mutations and variations associated with the development of diverticulitis are being discovered and are summarized here. The data for non-operative and outpatient management of diverticulitis are reviewed, as are pharmacologic agents studied for use in the secondary prevention of diverticulitis. Lastly, we present controversies in the surgical treatment of diverticulitis. This review will provide a synopsis of the last 5 years of literature relating to diverticulitis.

Challenging Surgical Dogma: Controversies in Diverticulitis

Diverticulosis of the sigmoid colon is common in the developed world, affecting approximately 33% of persons older than 60 years. Up to 15% of these patients will develop diverticulitis at some point in their lifetime. The incidence of diverticulitis has increased in the last decade, accounting for nearly 300,000 US hospital admissions and $1.8 billion in annual direct medical costs. With such a wide prevalence and diverse spectrum of clinical presentation, there are bound to be multiple controversies regarding disease management. This article will serve to educate the reader on several important areas to consider when treating this ubiquitous disease.

COLQ and ARHGAP15 are associated with diverticular disease and are expressed in the colon

BACKGROUND

Diverticular disease is a common but poorly understood disease of the gastrointestinal tract. Recent studies have identified several single nucleotide polymorphisms (SNPs) that are associated with diverticular disease.

MATERIALS AND METHODS

The genotypes of three SNPs (rs4662344 in ARHGAP15, rs7609897 in COLQ, and rs67153654 in FAM155A) were identified by Taqman assay in 204 patients with diverticular disease. Clinical characteristics were obtained from the medical record to study association with genotype. To evaluate gene expression in colon tissue, qPCR was performed on 24 patients with diverticulitis, and COLQ was localized using immunohistochemistry.

RESULTS

The ARHGAP15 and COLQ SNPs were significantly associated with both diverticular disease and specifically diverticulitis, while the FAM155A was not associated with either. No association was found with clinical disease characteristics. Heterozygous genotypes at the ARHGAP15 SNP was associated with lower ARHGAP15 expression in colon tissues. COLQ protein localized to the myenteric plexus in the colon.

CONCLUSIONS

This study confirmed association of the ARHGAP15 and COLQ SNPs with diverticular disease in our patients but could not confirm FAM155A SNP association. Neither of these SNPs appeared to associate with more severe disease, but genotype at the ARHGAP15 SNP did impact expression of ARHGAP15 in the colon. Additionally, this study is the first to localize COLQ in the colon. Its presence in the myenteric nervous system suggests COLQ SNP variants may contribute to diverticular disease by altering motility.

Evaluation of molecular and genetic predisposing parameters at diverticular disease of the colon

BACKGROUND

Diverticular disease (DD) refers to the presence of diverticula throughout the gastrointestinal (GI) tract, mainly along colon. DD might evolve into diverticulitis that is accompanied by severe clinical presentation, which includes abscess formation, perforation, stricture, obstruction and/or fistula.

AIM

The aim of the present review is to summarize the role of molecular and genetic factors in DD development, as well as their possible contribution towards new prognostic indicators, diagnostic algorithms and new therapeutic approaches.

METHODS AND RESULTS

Except from common predisposing parameters, several genetic mutations, immune factors, neurotransmitters, hormones and protein dysfunctions have been associated to the early onset of DD symptoms, pathogenesis and prognosis of the disease. Specific structural changes in the colonic wall, altered matrix composition and compromised motility have been verified as possible pathogenic factors for the development of DD. Dysregulation in peristaltic activity and reduced ability of the longitudinal muscle to relax following contraction has been also associated with DD evolution. In addition, it has been suspected that genetic defects combined with alterations in intestinal microbiota might play an important role in diverticulitis presentation.

TL1A: A New Potential Target in the Treatment of Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic inflammatory diseases of the gastrointestinal tract. In the last few years, the development of biological agents targeting cytokines and receptors involved in IBD pathogenesis has led to better outcomes and has improved the course of the disease. Despite their effectiveness, drugs such as tumor necrosis factor (TNF) inhibitors, anti-Interleukin-12/23 and anti-integrins, do not induce a response in about one-third of patients, and 40% of patients lose response over time. Therefore, more efficient therapies are required. Recent studies showed that TL1A (Tumor necrosis factor-like cytokine 1A) acts as a regulator of mucosal immunity and participates in immunological pathways involved in the IBD pathogenesis. In this review article, we analyze the role of TL1A as a new potential target therapy in IBD patients.

Genetic Risk Factors for Diverticular Disease-Emerging Evidence

Diverticular disease is traditionally understood as an environmental disease caused by diet and constipation. However, genes are increasing understood to play a role in pathogenesis. Twin studies suggest a substantial component of individual risk is due to heritable factors. Association of diverticular disease with other traits suggests an underlying biological mechanism and recently genome-wide association studies have described the genetic architecture underlying this complex phenotype. These studies suggest a new paradigm for understanding this common surgical disease.

Role of Inflammation in Pathophysiology of Colonic Disease: An Update

Diseases of the colon are a big health burden in both men and women worldwide ranging from acute infection to cancer. Environmental and genetic factors influence disease onset and outcome in multiple colonic pathologies. The importance of inflammation in the onset, progression and outcome of multiple colonic pathologies is gaining more traction as the evidence from recent research is considered. In this review, we provide an update on the literature to understand how genetics, diet, and the gut microbiota influence the crosstalk between immune and non‑immune cells resulting in inflammation observed in multiple colonic pathologies. Specifically, we focus on four colonic diseases two of which have a more established association with inflammation (inflammatory bowel disease and colorectal cancer) while the other two have a less understood relationship with inflammation (diverticular disease and irritable bowel syndrome).

Family History Is Associated With Recurrent Diverticulitis After an Episode of Diverticulitis Managed Nonoperatively

BACKGROUND

To date, the impact of family history on diverticulitis outcomes has been poorly described.

OBJECTIVE

This study aims to evaluate the association between family history and diverticulitis recurrence after an episode of diverticulitis managed nonoperatively.

DESIGN

This is a retrospective cohort study with prospective telephone follow-up.

SETTINGS

This study was conducted at 2 McGill University-affiliated tertiary care hospitals in Montreal, Canada.

PATIENTS

All immunocompetent patients with CT-proven left-sided diverticulitis who were managed nonoperatively from 2007 to 2017 were included.

INTERVENTION

A positive family history for diverticulitis, as assessed by a detailed telephone questionnaire, was obtained.

MAIN OUTCOME MEASURES

The primary outcome was diverticulitis recurrence occurring >60 days after the index episode. Secondary outcomes included a complicated recurrence and >1 recurrence (ie, re-recurrence).

RESULTS

Of the 879 patients identified in the database, 433 completed the telephone questionnaire (response rate: 48.9%). Among them, 173 (40.0%) had a positive family history of diverticulitis and 260 (60.0%) did not. Compared to patients with no family history, patients with family history had a younger median age (59.0 vs 62.0 years, p = 0.020) and a higher incidence of abscess (24.3% vs 3.5%, p < 0.001). After a median follow-up of 40.1 (17.4-65.3) months, patients with a positive family history had a higher cumulative incidence of recurrence (log-rank test: p < 0.001). On Cox regression, a positive family history remained associated with diverticulitis recurrence (HR, 3.74; 95% CI, 2.67-5.24). Among patients with a positive family history, >1 relative with a history of diverticulitis had a higher hazard of recurrence (HR, 2.93; 95% CI, 1.96-4.39) than patients with only 1 relative with a history of diverticulitis. Positive family history was also associated with the development of a complicated recurrence (HR, 8.30; 95% CI, 3.64-18.9) and >1 recurrence (HR, 2.03; 95% CI, 1.13-3.65).

LIMITATIONS

This study has the potential for recall and nonresponse bias.

CONCLUSION

Patients with a positive family history of diverticulitis are at higher risk for recurrent diverticulitis and complicated recurrences. See Video Abstract at http://links.lww.com/DCR/B215. LOS ANTECEDENTES FAMILIARES ESTÁN ASOCIADOS CON DIVERTICULITIS RECURRENTE, DESPUÉS DE UN EPISODIO DE DIVERTICULITIS MANEJADA SIN OPERACIÓN: Hasta la fecha, el impacto de los antecedentes familiares en los resultados de la diverticulitis, ha sido mal descrito.Evaluar la asociación entre los antecedentes familiares y la recurrencia de diverticulitis después de un episodio de diverticulitis manejado de forma no operatoria.Estudio de cohorte retrospectivo con seguimiento telefónico prospectivo.Dos hospitales de atención terciaria afiliados a la Universidad McGill en Montreal, Canadá.Todos los pacientes inmunocompetentes con diverticulitis izquierda comprobada por TAC, que fueron manejados sin cirugía desde 2007-2017.Una historia familiar positiva para diverticulitis, según lo evaluado por un detallado cuestionario telefónico.El resultado primario fue la recurrencia de diverticulitis ocurriendo > 60 días después del episodio índice. Resultados secundarios incluyeron una recurrencia complicada y >1 recurrencia (es decir, re-recurrencia).De los 879 pacientes identificados en la base de datos, 433 completaron el cuestionario telefónico (tasa de respuesta: 48,9%). Entre ellos, 173 (40.0%) tenían antecedentes familiares positivos de diverticulitis y 260 (60.0%) no tenían. Comparados con los pacientes sin antecedentes familiares, los pacientes con antecedentes familiares tenían una mediana de edad más joven (59.0 vs 62.0 años, p = 0.020) y una mayor incidencia de abscesos (24.3% vs 3.5%, p < 0.001). Después de una mediana de seguimiento de 40.1 (17.4-65.3) meses, los pacientes con antecedentes familiares positivos tuvieron una mayor incidencia acumulada de recurrencia (prueba de log-rank: p < 0.001). En la regresión de Cox, un historial familiar positivo, permaneció asociado con recurrencia de diverticulitis (HR, 3.74; IC 95%, 2.67-5.24). Entre los pacientes con antecedentes familiares positivos, >1 familiar con antecedentes de diverticulitis, tuvieron mayores riesgos de recurrencia (HR, 2.93; IC 95%, 1.96-4.39) en comparación de los pacientes con solo 1 familiar. La historia familiar positiva también se asoció con el desarrollo de una recurrencia complicada (HR, 8.30; IC 95%, 3.64-18.9) y >1 recurrencia (HR, 2.03; IC 95%, 1.13-3.65).Potencial de recuerdo y sesgo de no respuesta.Los pacientes con antecedentes familiares positivos de diverticulitis tienen un mayor riesgo para diverticulitis recurrente y recurrencias complicadas. Consulte Video Resumen http://links.lww.com/DCR/B215. (Traducción-Dr. Fidel Ruiz Healy).

Colonic diverticular disease

Diverticula are outpouchings of the intestinal wall and are common anatomical alterations detected in the human colon. Colonic diverticulosis (the presence of diverticula in the colon; referred to as diverticulosis) remains asymptomatic in most individuals but ~25% of individuals will develop symptomatic diverticulosis, termed colonic diverticular disease (also known as diverticular disease). Diverticular disease can range in severity from symptomatic uncomplicated diverticular disease (SUDD) to symptomatic disease with complications such as acute diverticulitis or diverticular haemorrhage. Since the early 2000s, a greater understanding of the pathophysiology of diverticulosis and diverticular disease, which encompasses genetic alterations, chronic low-grade inflammation and gut dysbiosis, has led to improvements in diagnosis and management. Diagnosis of diverticular disease relies on imaging approaches, such as ultrasonography, CT and MRI, as biomarkers alone are insufficient to establish a diagnosis despite their role in determining disease severity and progression as well as in differential diagnosis. Treatments for diverticular disease include dietary fibre, pharmacological treatments such as antibiotics (rifaximin), anti-inflammatory drugs (mesalazine) and probiotics, alone or in combination, and eventually surgery. Despite being effective in treating primary disease, their effectiveness in primary and secondary prevention of complications is still uncertain.

Multifocal Versus Conventional Unifocal Diverticulitis: A Comparison of Clinical and Transcriptomic Characteristics

BACKGROUND

The management of diverticulitis is compromised by difficulty in identifying patients who require surgery for recurrent or persistent disease. Here, we introduce the concept of multifocal diverticulitis (MFD), characterized by multiple episodes of diverticulitis occurring at different locations within the colon.

AIMS

To compare clinical characteristics, success of surgical management, and colonic transcriptomes of MFD patients to patients with conventional unifocal diverticulitis (UFD).

METHODS

This retrospective study included 404 patients with CT-confirmed diverticulitis episodes. Patients with diverticulitis seen in at least two different colonic locations were classified as the MFD group and compared to the UFD group based on number of episodes, sites of disease, family history, surgeries performed, and postoperative recurrence. RNA-seq was conducted on full-thickness colonic tissues of ten MFD and 11 UFD patients.

RESULTS

Twenty-eight patients (6.9%) with MFD were identified. MFD patients had more diverticulitis episodes and were more likely to have positive family history, have right-sided disease, require surgery, and have recurrence after surgery. All MFD patients treated with segmental resection had recurrence, while recurrence was less common in patients undergoing more extensive surgery (P < 0.001). Using RNA-seq, we identified 69 genes that were differentially expressed between MFD and UFD patients. Significantly down-regulated genes were associated with immune response pathways.

CONCLUSIONS

MFD appears to be a more severe subset of diverticulitis with a possible genetic component. Transcriptomic data suggest that MFD may be associated with alteration of the immune response.

Diverticular Disease in the Elderly

PURPOSE OF REVIEW

While few diseases are limited solely to the elderly, diverticular disease is clearly more prevalent with increasing age and therefore the aim of this review is to focus on the clinical implications of diverticular disease in the elderly.

RECENT FINDINGS

Diverticulitis in the elderly is best managed with an individualized treatment approach including considerations for selective antibiotic usage even in uncomplicated disease. Furthermore, due to the increased prevalence of ischemic colitis in the elderly and the similarities in presentation with diverticular hemorrhage, there needs to be a high index of suspicion and appropriate evaluation for ischemic colitis in patients with hematochezia, particularly if they have abdominal pain. The elderly are a vulnerable population where the index of suspicion for complications of diverticular disease should be high.

Diverticulosis and nine connective tissue disorders: epidemiological support for an association

Purpose: An underlying connective tissue disorder (CTD) may predispose to formation of intestinal diverticula. We assess the association of diverticulosis with nine selected CTDs, to inform the pathophysiology of diverticula. Methods: A population-based period-prevalence study. Individuals (3.5 million New Zealand residents born 1901-1986) with a health system record 1999-2016 were grouped into those with a hospital diagnosis of diverticulosis or diverticulitis (ICD-10-AM K57), and those without. Also recorded were any hospital diagnoses of nine selected CTDs. The association of exposure to diverticulosis and each CTD was assessed using logistic regressions adjusted for age, gender, ethnicity and region. Results: In all, 85,958 (2.4%) people had a hospital diagnosis of diverticulosis. Hospitalisation with diverticulosis was highly significantly associated with rectal prolapse (adjusted odds ratio [OR] = 3.9), polycystic kidney disease (OR = 3.8), heritable syndromes (Marfan or Ehlers-Danlos) (OR = 2.4), female genital prolapse (OR = 2.3), non-aortic aneurysm (OR = 2.3), aortic aneurysm (OR = 2.2), inguinal hernia (OR = 1.9) and dislocations of shoulder and other joints (OR = 1.7), but not subarachnoid haemorrhage (OR = 1.0). Conclusion: People with diverticulosis are more likely to have colonic extracellular matrix (ECM)/connective tissue alterations in anatomical areas other than the bowel, suggesting linked ECM/connective tissue pathology. Although biases may exist, the results indicate large-scale integrated studies are needed to investigate underlying genetic pathophysiology of colonic diverticula, together with fundamental biological studies to investigate cellular phenotypes and ECM changes.

Association study between two polymorphisms of tumor necrosis factor ligand superfamily member 15 (TNFSF15) gene and ulcerative colitis in south-west of Iran

BACKGROUND AND AIMS: Ulcerative colitis (UC) is the most prevalent clinical manifestation of the inflammatory bowel disease (IBD). Several candidate genes have been suggested to be involved in the genetic susceptibility or resistance in the development of UC. Among them, tumor necrosis factor ligand superfamily member 15 (TNFSF15) have been reported in association with IBD in several studies. The aim of this study was to investigate the association of TNFSF15 gene polymorphisms located in the promoter region, including rs6478108 (G/A -9706) and rs3810936 (G/A -15524) in Iranian patients with UC. METHODS: In this way, the two single nucleotide polymorphisms were studied in 115 patients with UC and 115 healthy controls with the same ethnic group from south-west of Iran. The genomic DNA of samples was genotyped using TaqMan Real-time PCR assay. This case-control study was conducted at the Department of Immunology, Jundishapur University of Medical Sciences, Ahvaz, Iran. RESULTS AND CONCLUSION: Our results did not confirm the formerly reported association of the studied polymorphisms with UC disease in comparison with healthy controls, neither with the type of the clinical forms of Colitis in the studied Iranian population. Comparing the genotype frequency of single nucleotide polymorphism (SNP) rs6478108, wild-type homozygous and heterozygote and mutant homozygote were 33%, 55.7%, and 11.3% in cases vs. 34.8%, 50.4%, and 14.8% in the controls (P = 0.6). The genotype frequency of SNP rs3810936 were 20.9%, 40.9%, and 38.2% in the cases compared to 18.3%, 44.3%, and 37.4% in controls, which was not significant ( P = 0.8). As multiple ethnic groups reside in all around the country, further studies using different ethnicities and/or larger sample size are required to clarify the role of these polymorphisms in the genetic susceptibility of UC in Iranian populations.

Epidemiology, Pathophysiology, and Treatment of Diverticulitis

Diverticulitis is a prevalent gastrointestinal disorder that is associated with significant morbidity and health care costs. Approximately 20% of patients with incident diverticulitis have at least 1 recurrence. Complications of diverticulitis, such as abdominal sepsis, are less likely to occur with subsequent events. Several risk factors, many of which are modifiable, have been identified including obesity, diet, and physical inactivity. Diet and lifestyle factors could affect risk of diverticulitis through their effects on the intestinal microbiome and inflammation. Preliminary studies have found that the composition and function of the gut microbiome differ between individuals with vs without diverticulitis. Genetic factors, as well as alterations in colonic neuromusculature, can also contribute to the development of diverticulitis. Less-aggressive and more-nuanced treatment strategies have been developed. Two multicenter, randomized trials of patients with uncomplicated diverticulitis found that antibiotics did not speed recovery or prevent subsequent complications. Elective surgical resection is no longer recommended solely based on number of recurrent events or young patient age and might not be necessary for some patients with diverticulitis complicated by abscess. Randomized trials of hemodynamically stable patients who require urgent surgery for acute, complicated diverticulitis that has not improved with antibiotics provide evidence to support primary anastomosis vs sigmoid colectomy with end colostomy. Despite these advances, more research is needed to increase our understanding of the pathogenesis of diverticulitis and to clarify treatment algorithms.

TL1A (TNFSF15) and DR3 (TNFRSF25): A Co-stimulatory System of Cytokines With Diverse Functions in Gut Mucosal Immunity

TL1A and its functional receptor DR3 are members of the TNF/TNFR superfamilies of proteins. Binding of APC-derived TL1A to lymphocytic DR3 provides co-stimulatory signals for activated lymphocytes. DR3 signaling affects the proliferative activity of and cytokine production by effector lymphocytes, but also critically influences the development and suppressive function of regulatory T-cells. DR3 was also found to be highly expressed by innate lymphoid cells (ILCS), which respond to stimulation by TL1A. Several recent studies with transgenic and knockout mice as well as neutralizing or agonistic antibodies for these two proteins, have clearly shown that TL1A/DR3 are important mediators of several chronic immunological disorders, including Inflammatory Bowel Disease (IBD). TL1A and DR3 are abundantly localized at inflamed intestinal areas of patients with IBD and mice with experimental ileitis or colitis and actively participate in the immunological pathways that underlie mucosal homeostasis and intestinal inflammation. DR3 signaling has demonstrated a dichotomous role in mucosal immunity. On the one hand, during acute mucosal injury it exerts protective functions by ameliorating the severity of acute inflammatory responses and facilitating tissue repair. On the other hand, it critically participates in the pro-inflammatory pathways that underlie chronic inflammatory responses, such as those that take place in IBD. These effects are mediated through modulation of the relative mucosal abundance and function of Th1, Th2, Th17, Th9, and Treg lymphocytes, but also of all types of ILCs. Recently, an important role was demonstrated for TL1A/DR3 as potential mediators of intestinal fibrosis that is associated with the presence of gut inflammation. These accumulating data have raised the possibility that TL1A/DR3 pathways may represent a valid therapeutic target for chronic immunological diseases. Nevertheless, applicability of such a therapeutic approach will greatly rely on the net result of TL1A/DR3 manipulation on the various cell populations that will be affected by this approach.

Role of TNFSF15 in the intestinal inflammatory response

Gastrointestinal diseases, specifically Crohn’s disease, ulcerative colitis, diverticular disease, and primary biliary cirrhosis are all characterized by complicated inflammation of the digestive tract. Their pathology is multifactorial, and risk factors encompass both genetic and environmental factors. Recent advances in the genetic component of inflammatory bowel diseases (IBDs) have revealed that the tumor necrosis factor superfamily member 15 (TNFSF15) contains a number of risk alleles associated not only with IBD but also with other diseases such as diverticular disease and primary biliary cirrhosis. These risk alleles in TNFSF15 and the altered expression of its gene product can serve as the common ground between these disorders by explaining at least some of the underlying processes that lead to a dysregulated immune response and subsequent chronic inflammation. Here, we aim to outline how the TNFSF15 gene is involved in the proliferation and cell fate of different populations of T cells and subsequently in the control of both pro- and anti-inflammatory cytokines. Furthermore, we summarize what is currently known of TNFSF15 control region variants, how they are associated with each mentioned disease, and how these variants can explain the autoimmune pathology of said diseases through altered TNFSF15 expression.

Genome-wide association analyses identify 39 new susceptibility loci for diverticular disease

Diverticular disease is common and has a high morbidity. Treatments are limited owing to the poor understanding of its pathophysiology. Here, to elucidate its etiology, we performed a genome-wide association study of diverticular disease (27,444 cases; 382,284 controls) from the UK Biobank and tested for replication in the Michigan Genomics Initiative (2,572 cases; 28,649 controls). We identified 42 loci associated with diverticular disease; 39 of these loci are novel. Using data-driven expression-prioritized integration for complex traits (DEPICT), we show that genes in these associated regions are significantly enriched for expression in mesenchymal stem cells and multiple connective tissue cell types and are co-expressed with genes that have a role in vascular and mesenchymal biology. Genes in these associated loci have roles in immunity, extracellular matrix biology, cell adhesion, membrane transport and intestinal motility. Phenome-wide association analysis of the 42 variants shows a common etiology of diverticular disease with obesity and hernia. These analyses shed light on the genomic landscape of diverticular disease.

Characteristics and associated risk factors of diverticular disease assessed by magnetic resonance imaging in subjects from a Western general population

OBJECTIVES

Diverticular disease represents an increasing pathology and healthcare burden worldwide. Our aim was to study the prevalence, extent and distribution of asymptomatic diverticular disease assessed by magnetic resonance imaging (MRI) in a sample of a Western population.

METHODS

Subjects from a population-based cohort study who underwent 3-T MRI were analyzed for the prevalence and extent of diverticula of the colon using an isotropic VIBE-Dixon gradient-echo sequence. The extent of diverticular disease was categorized according to the number of diverticula in each colonic segment. Univariate and adjusted analyses were performed to assess associated characteristics and risk factors.

RESULTS

Among 393 subjects included in the analysis (56.4 ± 9.2 years, 57.5% males), 164 (42%) had diverticular disease, with the highest prevalence in the left-sided colonic segments (93% diverticular disease in the descending and sigmoid segment). Subjects with advanced diverticular disease were older (62.1 vs. 54.4 years) and had a higher body mass index (BMI), LDL cholesterol levels and systolic blood pressure (30.2 ± 5.1 vs. 27.8 ± 4.9 kg/m², 149.8 ± 29.3 vs. 135.2 ± 32.9 mg/dl and 128.2 ± 14.1 vs. 118.4 ± 16.1 mmHg, respectively; all p > 0.003) compared with subjects without diverticular disease. In contrast, no significant correlation could be found for gender, physical activity, smoking status and alcohol consumption (all p > 0.31). Intra-rater reliability was excellent for all colonic segments (intra-class correlation [ICC] = 0.99-1.00), and inter-rater reliability was excellent for left- and right-sided colonic segments (ICC = 0.84-0.97).

CONCLUSIONS

These findings provide insights into the disease mechanism of asymptomatic diverticular disease and may help to improve prevention of diverticulosis and its associated complications.

KEY POINTS

• Overall prevalence of asymptomatic diverticular disease assessed by MRI was 42%, affecting predominantly the left-sided colon. • Asymptomatic diverticular disease was associated with age and cardiometabolic risk factors. • Magnetic resonance imaging reveals insights into the pathophysiologic mechanism of asymptomatic diverticular disease.

Progress and challenges in the management of diverticular disease: which treatment?

Diverticular disease of the colon (DDC) includes a spectrum of conditions from asymptomatic diverticulosis to symptomatic uncomplicated diverticulosis, segmental colitis associated with diverticulosis, and acute diverticulitis without or with complications that may have serious consequences. Clinical and scientific interest in DDC is increasing because of the rising incidence of all conditions within the DDC spectrum, a better, although still limited understanding of the pathogenic mechanisms involved; the increasing socioeconomic burden; and the new therapeutic options being tested. The goals of treatment in DDC are symptom and inflammation relief and preventing disease progression or recurrence. The basis for preventing disease progression remains a high-fiber diet and physical exercise, although evidence is poor. Other current strategies do not meet expectations or lack a solid mechanistic foundation; these strategies include modulation of gut microbiota or dysbiosis with rifaximin or probiotics, or using mesalazine for low-grade inflammation in uncomplicated symptomatic diverticulosis. Most acute diverticulitis is uncomplicated, and the trend is to avoid hospitalization and unnecessary antibiotic therapy, but patients with comorbidities, sepsis, or immunodeficiency should receive broad spectrum and appropriate antibiotics. Complicated acute diverticulitis may require interventional radiology or surgery, although the best surgical approach (open versus laparoscopic) remains a matter of discussion. Prevention of acute diverticulitis recurrence remains undefined, as do therapeutic strategies. Mesalazine with or without probiotics has failed to prevent diverticulitis recurrence, whereas new studies are needed to validate preliminary positive results with rifaximin. Surgery is another option, but the number of acute events cannot guide this indication. We need to identify risk factors and disease progression or recurrence mechanisms to implement appropriate preventive strategies.

Pathophysiology of diverticular disease

Inflammation of diverticula, or outpouchings of the colonic mucosa and submucosa through the muscularis layer, leads to diverticulitis. The development of diverticular disease, encompassing both diverticulosis and diverticulitis, is a result of genetic predisposition, lifestyle, and environmental factors, including the microbiome. Areas covered: Previous reports implicated genetic predisposition, environmental factors, and colonic dysmotility in diverticular disease. Recent studies have associated specific host immune responses and the microbiome as contributors to diverticulitis. To review pertinent literature describing pathophysiological factors associated with diverticulosis or diverticulitis, we searched the PubMed database (March 2018) for articles considering the role of colonic architecture, genetic predisposition, environment, colonic motility, immune response, and the microbiome. Expert commentary: In the recent years, research into the molecular underpinnings of diverticular disease has enhanced our understanding of diverticular disease pathogenesis. Although acute uncomplicated diverticulitis is treated with broad spectrum antibiotics, evaluation of the microbiome has been limited and requires further comprehensive studies. Evidence suggests that a deregulation of the host immune response is associated with both diverticulosis and diverticulitis. Further examining these pathways may reveal proteins that can be therapeutic targets or aid in identifying biological determinants of clinical or surgical decision making.

A Variant of COL3A1 (rs3134646) Is Associated With Risk of Developing Diverticulosis in White Men

BACKGROUND

Colonic diverticulosis is one of the most common gastroenterological disorders. Although diverticulosis is typically benign, many individuals develop diverticulitis or other aspects of diverticular disease. Diverticulosis is thought to stem from a complex interaction of environmental, dietary, and genetic factors; however, the contributing genetic factors remain unknown.

OBJECTIVE

The aim of our present study was to determine the role of genetic variants within genes encoding for collagens of the connective tissue in diverticulosis.

DESIGN

This was a transsectional genetic association study.

SETTINGS

This study was conducted at three tertiary referral centers in Germany and Lithuania.

PATIENTS

Single-nucleotide polymorphisms in COL3A1 (rs3134646, rs1800255) and COL1A1 (rs1800012) were genotyped in 422 patients with diverticulosis and 285 controls of white descent by using TaqMan assays.

MAIN OUTCOME MEASURES

The association of colonoscopy-proven diverticulosis with genetic polymorphisms with herniations was assessed in multivariate models.

RESULTS

The rs3134646, rs1800255, and rs1800012 variants were significantly associated with the risk of developing diverticulosis in the univariate model; however, these associations were not significant in the multivariate logistic regression analysis including additional nongenetic variables. When selectively analyzing sexes, the genotype AA (AA) in rs3134646 remained significantly associated with diverticulosis in men (OR, 1.82; 95% CI, 1.04-3.20; p = 0.04).

LIMITATIONS

Because a candidate approach was used, additional relevant variants could be missed. Within our cohort of patients with diverticulosis, only a small proportion had diverticular disease and thus, we could not examine the variants in these subgroups. Functional studies, including the analysis of the involved collagens, are also warranted.

CONCLUSIONS

Our study shows that a variant of COL3A1 (rs3134646) is associated with the risk of developing colonic diverticulosis in white men, whereas rs1800255 (COL3A1) and rs1800012 (COL1A1) were not associated with this condition after adjusting for confounding factors. Our data provide novel valuable insights in the genetic susceptibility to diverticulosis. See Video Abstract at http://links.lww.com/DCR/A504.

Crohn's Disease Candidate Gene Alleles Predict Time to Progression from Inflammatory B1 to Stricturing B2, or Penetrating B3 Phenotype

AIM

Crohn's disease (CD) patients are mostly diagnosed with the uncomplicated inflammatory form of disease; however, the majority will progress to complicated stricturing or penetrating disease over time. It is important to identify patients at risk for disease progression at an early stage. The aim of our study was to examine the role of 33 candidate CD genes as possible predictors of disease progression and their influence on time to progression from an inflammatory to a stricturing or penetrating phenotype.

METHODS

Patients with an inflammatory phenotype at diagnosis were followed for 10 years and 33 CD-associated polymorphisms were genotyped. To test for association with CD, 449 healthy individuals were analyzed as the control group.

RESULTS

Ten years after diagnosis, 39.1% of patients had not progressed beyond an inflammatory phenotype, but 60.9% had progressed to complicated disease, with average time to progression being 5.91 years. Association analyses of selected single nucleotide polymorphisms (SNPs) confirmed associations with CD for 12 SNPs. Furthermore, seven loci were associated with disease progression, out of which SNP rs4263839 in the gene TNFSF15 showed the strongest association with disease progression and the frameshift mutation rs2066847 in the gene NOD2 showed the strongest association with time to progression.

CONCLUSIONS

The results of our study identified specific genetic biomarkers as useful predictors of both disease progression and speed of disease progression in patients with CD.

Identification of a rare LAMB4 variant associated with familial diverticulitis through exome sequencing

Diverticulitis is a chronic disease of the colon in which diverticuli, or outpouching through the colonic wall, become inflamed. Although recent observations suggest that genetic factors may play a significant role in diverticulitis, few genes have yet been implicated in disease pathogenesis and familial cases are uncommon. Here, we report results of whole exome sequencing performed on members from a single multi-generational family with early onset diverticulitis in order to identify a genetic component of the disease. We identified a rare single nucleotide variant in the laminin β 4 gene (LAMB4) that segregated with disease in a dominant pattern and causes a damaging missense substitution (D435N). Targeted sequencing of LAMB4 in 148 non-familial and unrelated sporadic diverticulitis patients identified two additional rare variants in the gene. Immunohistochemistry indicated that LAMB4 localizes to the myenteric plexus of colonic tissue and patients harboring LAMB4 variants exhibited reduced LAMB4 protein levels relative to controls. Laminins are constituents of the extracellular matrix and play a major role in regulating the development and function of the enteric nervous system. Reduced LAMB4 levels may therefore alter innervation and morphology of the enteric nervous system, which may contribute to colonic dysmotility associated with diverticulitis.

Recent advances in understanding and managing diverticulitis

In the past few decades, the increasing socioeconomic burden of acute diverticulitis (AD) has become evident, and with the growth of the population age, this significant economic impact will likely continue to rise. Furthermore, recent evidence showed an increased rate of hospital admissions especially evident among women and younger individuals. The natural history and pathophysiology of this clinical condition is still to be fully defined, and efforts continue to be made in the identification of risk factors and the establishment of relative preventive strategies. The actual therapeutic strategies aimed to modulate gut microbiota, such as rifaximin or probiotics, or to reduce mucosal inflammation, such as mesalazine, present a relatively poor efficacy for both the prevention of the first AD episode (primary prevention) and its recurrence (secondary prevention). In the last few years, the main goal achieved has been in the management of AD in that uncomplicated AD can, to a larger extent, be managed in an outpatient setting with no or little supportive therapy, a strategy that will certainly impact on the health costs of this disease. The problem of AD recurrence remains a topic of debate. The aim of this review is to present updated evidence on AD epidemiology and relative open clinical questions and to analyze in detail predisposing and protective factors with an attempt to integrate their possible modes of action into the several pathogenic mechanisms that have been suggested to contribute to this multifactorial disease. A unifying hypothesis dealing with the colonic luminal and extra-luminal microenvironments separately is provided. Finally, evidence-based changes in therapeutic management will be summarized. Because of an ascertained multifactorial pathogenesis of uncomplicated and complicated AD, it is probable that a single 'causa prima' will not be identifiable, and a better stratification of patients could allow one to pursue tailored therapeutic algorithm strategies.

RNA-seq implicates deregulation of the immune system in the pathogenesis of diverticulitis

Individuals with diverticula or outpouchings of the colonic mucosa and submucosa through the colonic wall have diverticulosis, which is usually asymptomatic. In 10-25% of individuals, the diverticula become inflamed, resulting in diverticulitis. Very little is known about the pathophysiology or gene regulatory pathways involved in the development of diverticulitis. To identify these pathways, we deep sequenced RNAs isolated from full-thickness sections of sigmoid colon from diverticulitis patients and control individuals. Specifically for diverticulitis cases, we analyzed tissue adjacent to areas affected by chronic disease. Since the tissue was collected during elective sigmoid resection, the disease was in a quiescent state. A comparison of differentially expressed genes found that gene ontology (GO) pathways associated with the immune response were upregulated in diverticulitis patients compared with nondiverticulosis controls. Next, weighted gene coexpression network analysis was performed to identify the interaction among coexpressed genes. This analysis revealed RASAL3, SASH3, PTPRC, and INPP5D as hub genes within the brown module eigengene, which highly correlated (r = 0.67, P = 0.0004) with diverticulitis. Additionally, we identified elevated expression of downstream interacting genes. In summary, transcripts associated with the immune response were upregulated in adjacent tissue from the sigmoid colons of chronic, recurrent diverticulitis patients. Further elucidating the genetic or epigenetic mechanisms associated with these alterations can help identify those at risk for chronic disease and may assist in clinical decision management.NEW & NOTEWORTHY By using an unbiased approach to analyze transcripts expressed in unaffected colonic tissues adjacent to those affected by chronic diverticulitis, our study implicates that a defect in the immune response may be involved in the development of the disease. This finding expands on the current data that suggest the pathophysiology of diverticulitis is mediated by dietary, age, and obesity-related factors. Further characterizing the immunologic differences in diverticulitis may better inform clinical decision-making.

Sequence variants in ARHGAP15, COLQ and FAM155A associate with diverticular disease and diverticulitis

Diverticular disease is characterized by pouches (that is, diverticulae) due to weakness in the bowel wall, which can become infected and inflamed causing diverticulitis, with potentially severe complications. Here, we test 32.4 million sequence variants identified through whole-genome sequencing (WGS) of 15,220 Icelanders for association with diverticular disease (5,426 cases) and its more severe form diverticulitis (2,764 cases). Subsequently, 16 sequence variants are followed up in a diverticular disease sample from Denmark (5,970 cases, 3,020 controls). In the combined Icelandic and Danish data sets we observe significant association of intronic variants in ARHGAP15 (Rho GTPase-activating protein 15; rs4662344-T: P=1.9 × 10^-18, odds ratio (OR)=1.23) and COLQ (collagen-like tail subunit of asymmetric acetylcholinesterase; rs7609897-T: P=1.5 × 10^-10, OR=0.87) with diverticular disease and in FAM155A (family with sequence similarity 155A; rs67153654-A: P=3.0 × 10^-11, OR=0.82) with diverticulitis. These are the first loci shown to associate with diverticular disease in a genome-wide study.

Diverticular disease is associated with benign intra-abdominal cystic disease

BACKGROUND

Diverticular disease (DD) and hepatic and renal cysts have been linked with defects in collagen and dysfunctional matrix metalloproteinases.

METHODS

Consecutive abdominal computed tomography scans between January-July 2015 were prospectively studied to determine a correlation between visceral cysts and DD. Patients with a sigmoid colectomy for pathology other than DD and scans in which DD and/or solid organs were not fully visualized were excluded. A subgroup analysis was performed on youthful DD patients (<55 years of age, n = 32) vs. older controls (>55, n = 213).

RESULTS

238 DD patients (50.8% male) and 369 controls (40.5% male, p = .02) were included. Incidence of visceral cystic disease in DD patients vs. controls was 71.4% vs. 22.5% (p < 0.00001). Renal cysts, present in 53.4% of the DD patients and 18.7% of the controls (p < .00001), were more common than hepatic cysts in both groups. Hepatic cyst prevalence was 8.8 vs. 2.4% (p = .0008). In the subgroup analysis, cystic disease was present in 56.2% of youthful DD patients vs. 29.1% of older controls (p = .004).

CONCLUSIONS

A significant association between cystic disease and DD was demonstrated overall and in subgroup analysis inclusive of youthful DD patients and older controls. These findings suggest a global defect in connective tissue integrity in DD patients.

Diverticulitis and Crohn's disease have distinct but overlapping tumor necrosis superfamily 15 haplotypes

BACKGROUND

Diverticulitis (DD) and Crohn's disease (CD) have overlapping features including bowel structuring, inflammation, and infection. Tumor necrosis superfamily 15 (TNFSF15) is an immunoregulatory, anti-angiogenic gene. CD has been previously associated with a haplotype of five TNFSF15 single-nucleotide polymorphism alleles: rs3810936 (G allele), rs6478108 (A), rs6478109 (G), rs7848647 (G), and rs7869487 (A). We aimed to determine the TNFSF15 risk haplotype for DD versus controls with a subgroup analysis of youthful DD patients (aged ≤55 y) versus older controls (aged ≥55 y).

METHODS

A total of 148 diverticulitis patients (90 aged ≤55 y) and 200 controls (87 aged ≥55 y) were genotyped using our custom-designed Illumina Veracode microarray chip. Genotypes from rs3810936, rs6478108, rs6478109, rs7848647, rs7869487 and two additional TNFSF15 single nucleotide polymorphisms, rs3810936 and rs11554257, were analyzed. PHASE version 2.1, R with HaploStats and the Broad Institute's Haploview program were used for statistics and imputed haplotype frequency. Permutation corrected for multiple comparisons.

RESULTS

The CD GAGGA haplotype was significantly associated with diverticulitis (P = 0.03) in the all DD versus all controls comparison. A second haplotype, rs6478108 (A), rs6478109 (G), rs7869487 (A), and rs4263839 (G), was also associated with DD in this cohort (P = 0.025). A third haplotype rs6478108 (A), rs6478109 (G), rs7848647 (G) and rs7869487 (A), rs4263839 (G) was demonstrated in the DD < 55 versus controls >55 comparison (P = 0.045).

CONCLUSIONS

Distinct but overlapping TNFSF15 haplotypes were demonstrated in diverticulitis patients versus healthy controls when compared with the known Crohn's risk haplotype suggesting similar but distinct genetic predispositions. This study strengthens the role for a genetic predisposition to diverticulitis that involves the TNFSF15 gene.

Inflammation, Genetics, Dysbiosis, and the Environment: New Paradigms for Diagnosis in Complex Chronic Gut Syndromes

Chronic and complex gut syndromes are complex to diagnose and manage, but good clinicopathologic correlation, recognition of new entities, understanding (and understanding the limits) of genetic susceptibility and the importance of the microbiome, dysbiosis and influence of the environmental allows development of new models for diagnosis. An awareness of overlap in chronic gut syndromes has been clarified by the realization that inflammatory pathways involved in chronic gut disease can arise through variable gene expression that is influenced by the environment in susceptible individuals. Recent advances in diagnosis of inflammatory bowel disease and diverticular disease may be aided by genetic tests but at present, pathology and some simple biomarkers such as C-reactive protein and fecal calprotectin are still mainstream investigative measures. When made aware of the importance of these recent developments in chronic gut disease, histopathologists can easily recognize colonic spirochetosis and microscopic colitis. The role of the microbiome alongside interaction with the environment, are now recognized as key players in complex diseases. Integration of appropriate and cost-effective tests into new paradigms will surely advance patients' well-being and allow development of curative-targeted therapies rather than current treatments which, in many cases, merely alleviate symptoms.

Diverticulosis and Diverticulitis

Diverticular disease is a common condition that is associated with variable presentations. For this review article, we performed a review of articles in PubMed through February 1, 2016, by using the following MeSH terms: colon diverticula, colonic diverticulitis, colonic diverticulosis, colonic diverticulum, colonic diverticula, and diverticula. Diverticula are structural alterations within the colonic wall that classically form "pockets" referred to as diverticula. Diverticula form from herniation of the colonic mucosa and submucosa through defects in the circular muscle layers within the colonic wall. Often this is at the sites of penetrating blood vessels in the colon. Diverticular disease is extremely common, which resulted in 2,682,168 outpatient visits and 283,355 hospitalization discharges for diverticulitis or diverticulosis in 2009. Diverticulosis is one of the most common detected conditions found incidentally on colonoscopy. Risk factors for the development of diverticulitis include obesity, smoking, nonsteroidal anti-inflammatory drugs, corticosteroids, and opiates. In contrast, fiber may be protective, but recent studies have questioned the role of fiber in developing diverticular disease. Most patients with diverticulosis will be asymptomatic, but a subset of patients may develop nonspecific abdominal pain (isolated or recurrent), diverticulitis, or segmental colitis associated with diverticulosis. Classically, the treatment of diverticulitis has included antibiotics for all patients. More recent evidence indicates that in mild to even moderate uncomplicated diverticulitis, antibiotics may not be as necessary as initially believed. In more complicated diverticulitis, intravenous antibiotics and surgery may be necessary. Once a patient has had an attack of diverticulitis, increasing fiber may help prevent future attacks. Other modalities such as 5-aminosalicylate products, antibiotics, and probiotics are still of unclear benefit in preventing future episodes of diverticulitis. Similarly, even when patients develop recurrent episodes of diverticulitis, surgery may not be necessary as a prophylactic treatment.

New medical strategies for the management of acute diverticulitis

Acute diverticulitis, defined as acute inflammation of a colonic diverticulum, is a common emergency presentation managed by both surgeons and physicians. There have been advances in the medical treatments offered to patients in recent years. Factors predisposing individuals to the development of acute diverticulitis include obesity, smoking, lack of physical activity and medication use, such as NSAIDs. Although widely used, there is limited evidence on the efficacy of individual antibiotic regimens and antibiotic treatment may not be required in all patients. Mesalazine seems to be the only effective treatment for the primary prevention of acute diverticulitis. Finally, evidence of effective measures for the prevention of recurrence is lacking. Furthermore, high-quality randomized controlled trials are required for medical treatments in patients with acute diverticulitis, if management is to be evidence based.

Management of sigmoid diverticulitis: an update

The role, indications and modalities of elective resection for sigmoid diverticulitis remain the cause of fierce debate. During the past two decades clinicians have increasingly recognized that: (1) young patients (<50) are no more at risk to develop more aggressive course of the disease; and (2) patients who present initially with a first uncomplicated attack are no more at risk for developing subsequent complicated diverticulitis requiring emergency surgery. Hence, the previously well-recognized indications (based upon age of the patients or the number of attacks) are no longer valid. Yet, the number of sigmoid resections performed for diverticulitis in industrialized countries is increasing, which seems to indicate that in many cases, uncomplicated sigmoid diverticulitis progressively evolves towards a chronic symptomatic condition, which significantly impacts upon the patients' quality of life. The aims of this review are twofold: (1) to identify which disease presentation still represents good indications for elective laparoscopic sigmoid resection; and (2) to summarize the technical aspects of surgery for a benign condition, such as diverticular disease.

Diverticulosis today: unfashionable and still under-researched

Diverticulosis of the colon is a widespread disease, and its prevalence is increasing especially in the developing world. The underlying pathological mechanisms that cause the formation of colonic diverticula remain unclear but are likely to be the result of complex interactions among age, diet, genetic factors, colonic motility, and changes in colonic structure. The large majority of patients remain asymptomatic throughout their life, one fifth of them become symptomatic (developing the so-called 'diverticular disease') while only a minority of these will develop acute diverticulitis. The factors predicting the development of symptoms remain to be identified. Again, it is generally recognized that diverticular disease occurrence is probably related to complex interactions among colonic motility, diet, lifestyle, and genetic features. Changes in intestinal microflora due to low-fiber diet and consequent low-grade inflammation are thought to be one of the mechanisms responsible for symptoms occurrence of both diverticular disease and acute diverticulitis. Current therapeutic approaches with rifaximin and mesalazine to treat the symptoms seem to be promising. Antibiotic treatment is currently advised only in acute complicated diverticulitis, and no treatment has currently proven effective in preventing the recurrence of acute diverticulitis. Further studies are required in order to clarify the reasons why diverticulosis occurs and the factors triggering occurrence of symptoms. Moreover, the reasons why rifaximin and mesalazine work in symptomatic diverticular disease but not in acute diverticulitis are yet to be elucidated.

The genetic epidemiology of diverticulosis and diverticular disease: Emerging evidence

Diverticular disease (DD) is one of the most prevalent gastrointestinal disorders. The pathogenesis of diverticulosis and DD is controversially discussed. Current studies call the traditional concept of a fibre-deficient diet causing the development of diverticula into question. Data from two recent twin studies have provided conclusive evidence for a strong genetic component to diverticulosis. Although genomewide association studies have provided new insights into the polygenic architecture of human diseases, genomic research in diverticulosis and DD has just been started. This is an astonishing fact given the high morbidity and mortality of the disease, as well as the substantial economic burden on health care systems. For this review, we provide an update of the molecular pathobiology and summarise recent evidence supporting the hypothesis that distinct, yet unidentified genetic variants contribute to the development of diverticulosis and DD.

Tumor Necrosis Factor-like Cytokine TL1A and Its Receptors DR3 and DcR3: Important New Factors in Mucosal Homeostasis and Inflammation

Tumor necrosis factor (TNF)-like cytokine 1A (TL1A) is a member of the TNF superfamily of proteins (TNFSF15), which signals through association with death domain receptor 3 (DR3). Decoy receptor 3 (DcR3) competes with DR3 for TL1A binding and inhibits functional signaling. These proteins are significantly upregulated in inflamed intestinal tissues, and their pathogenetic importance for inflammatory bowel disease (IBD) is suggested by accumulating evidence. TL1A/DR3 induce costimulatory signals to activated lymphocytes, including the gut-specific populations of CD4+CD161+ and CD4+CCR9+ cells, affecting all major effector pathways and inducing the mucosal upregulation of Th1, Th2, and Th17 factors. They may also participate in mucosal homeostasis and defense against pathogens through their effects on the development and function of the recently described innate lymphoid cells. T-regulatory lymphocytes highly express DR3, and they respond to TL1A stimulation also. Mechanistic studies by transgenic expression of TL1A, deletion of TL1A or DR3, and therapeutic blockade by anti-TL1A antibodies all support the critical involvement of the corresponding pathways in the pathogenesis of chronic mucosal inflammation. Wide genome association studies have identified IBD-specific polymorphisms in TNFSF15 gene, which have functional implications and serve as poor prognostic factors. Recently, TL1A blockade in mice was presented as a unique pharmacological treatment for the reversal of established intestinal fibrosis. Finally, TL1A/DR3 signaling seems to critically participate in extraintestinal inflammatory conditions that are frequently associated with IBD as part of the gut-joint-skin-eye axis. These converging lines of evidence make TL1A/DR3 a suitable model for personalized approaches to IBD therapy.

Surgical diverticulitis is not associated with defects in the expression of wound healing genes

PURPOSE

The development of diverticuli may represent defects in collagen vascular tissue integrity possibly from a genetic predisposition. We evaluated the tissue expression of wound healing genes in sigmoid tissue from youthful patients undergoing surgery for diverticulitis and thus would more likely suffer from a genetic predisposition (SD mean age 39 ± 0.9) versus controls in the form of patients over the age of 50 (mean age 52.9 ± 10.5 years) without evidence of diverticular disease.

METHODS

The mRNA expression of 84 genes associated with the extracellular matrix, cellular adhesion, growth factors, inflammatory cytokines, and signal transduction was evaluated in 16 SD and 15 control tissues using a Qiagen Wound Healing Array. Vitronectin, the gene protein with the highest potential significance on raw analysis, was further investigated using a Taqman assay with an additional 11 SD (total n = 27) and four control (total n = 19) samples. Statistics were by Student's t and Mann-Whitney tests with Bonferroni correction.

RESULTS

No significant differences in mRNA expression between the SD and control tissue in the 84 measured genes were demonstrated after correction. Vitronectin mRNA expression was downregulated 2.7-fold in SD tissue vs. tissue from non-neoplastic control patients (p = 0.001 raw/0.08 corrected). However, on vitronectin TaqMan analysis, no difference in expression was seen in SD vs. all controls or in all subset comparisons.

CONCLUSIONS

The lack of significant alteration in mRNA expression of traditionally associated wound healing genes/proteins in young SD patients suggests that such genes play a minor role in the genetic predisposition to youthful diverticulitis.

Review article: the pathophysiology and medical management of diverticulosis and diverticular disease of the colon

BACKGROUND

The incidence of diverticulosis and diverticular disease of the colon, including diverticulitis, is increasing worldwide, and becoming a significant burden on national health systems. Treatment of patients with diverticulosis and DD is generally based on high-fibre diet and antibiotics, respectively. However, new pathophysiological knowledge suggests that further treatment may be useful.

AIM

To review the current treatment of diverticulosis and diverticular disease.

METHODS

A search of PubMed and Medline databases was performed to identify articles relevant to the management of diverticulosis and diverticular disease. Major international conferences were also reviewed.

RESULTS

Two randomised controlled trials (RCT) found the role of antibiotics in managing acute diverticulitis to be questionable, particularly in patients with no complicating comorbidities. One RCT found mesalazine to be effective in preventing acute diverticulitis in patients with symptomatic uncomplicated diverticular disease. The role of rifaximin or mesalazine in preventing diverticulitis recurrence, based on the results of 1 and 4 RCTs, respectively, remains unclear. RCTs found rifaximin and mesalazine to be effective in treating symptomatic uncomplicated diverticular disease. The use of probiotics in diverticular disease and in preventing acute diverticulitis occurrence/recurrence appears promising but unconclusive. Finally, the role of fibre in treating diverticulosis remains unclear.

CONCLUSIONS

Available evidence suggests that antibiotics have a role only in the treatment of complicated diverticulitis. It appears to be some evidence for a role for rifaximin and mesalazine in treating symptomatic uncomplicated diverticular disease. Finally, there is not currently adequate evidence to recommend any medical treatment for the prevention of diverticulitis recurrence.

Risk Factors for the Development of an Incisional Hernia after Sigmoid Resection for Diverticulitis: An Analysis of 33 Patient, Operative and Disease-associated Factors

Incisional hernia (IH) is a relatively common sequelae of sigmoidectomy for diverticulitis. The aim of this study was to investigate factors that may predict IH in diverticulitis patients. Two hundred and one diverticulitis patients undergoing sigmoidectomy between January 2002 and December 2012 were identified (mean follow-up 5.15 ± 2.33 years). Patients with wound infections were excluded. Thirteen patient-associated, three diverticular disease-related, and 17 operative variables were evaluated in patients with and without IH. Volumetric fat was measured on pre-operative CTs. Fischer's exact, χ2, and Mann–Whitney tests and multivariate regression analysis were used for statistics. Thirty-four (17%) patients had an IH. On multivariate analysis, wound packing (OR 3.4, P = 0.017), postoperative nonwound infection (OR 7.4, P = 0.014), and previous hernia (OR 3.6, P = 0.005) were as independent predictors of IH. Fifteen of 34 (44%) patients who developed a hernia had a history of prior hernia. Of 33 potential risk factors analyzed, including smoking, chronic obstructive pulmonary disease, and obesity, the only patient factor present preoperatively associated with increased risk of a postsigmoidectomy hernia after multivariate analysis was a history of a previous hernia. Preoperative identification of patients with a history of hernia offers the opportunity to employ measures to decrease the likelihood of IH.