The genetic epidemiology of diverticulosis and diverticular disease: Emerging evidence

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.

Right-side diverticulitis

Colonic diverticula develop at specific weak spots, where the vasa recta enter the colonic circular smooth muscle layer.1 They are usually seen in the left colon. Their most common complication is diverticulitis, with mild cases resolving even without antibiotic therapy.2 Right-side diverticulitis develops in only 1.5% of cases, primarily on the anterior aspect of the cecum, proximal to the ileocecal valve (80%).4 Given its low incidence, location, and the fact that it involves younger patients, a differential diagnosis is needed to rule out abdominal inflammatory conditions such as appendicitis or ileitis, as well as gynecological disorders. Diverticulitis is diagnosed using imaging modalities. Computed tomography (CT) is the modality of choice,5 and confirmation is required after clinical remission, primarily using colonoscopy. We studied a series of 3 cases of patients initially diagnosed with acute, uncomplicated right-side diverticulitis who were admitted to the Gastroenterology Department, Hospital de León, from January to December 2023. Our goal was to confirm a presumptive diagnosis of right-side diverticulitis using delayed endoscopy or barium enema to ascertain the presence of right-side diverticulosis and rule out other conditions manifesting with abdominal pain in the right iliac fossa. Cases 1 and 3 were admitted with an accurate diagnosis of right-side diverticulitis. Case 1 was confirmed by ambulatory colonoscopy, and case 3 was confirmed by barium enema because of a history of previous colonoscopy without findings. All three patients required surgical assessment to rule out appendicular involvement. The imaging technique of choice was CT, using the WSES scale for severity grading. Case 2 was diagnosed with right-side diverticulitis by means of ultrasonography, and its origin was later confirmed to be in the sigmoid colon. The remaining clinical, laboratory, and diagnostic characteristics are listed in Table 1.

Quantification and significance of extraprostatic findings on prostate MRI: a retrospective analysis and three-tier classification

OBJECTIVES

To quantify extraprostatic findings (EPFs) on prostate MRI, estimate the proportion of reported and unreported EPFs, assess their clinical importance, and propose standardized reporting of EPFs.

MATERIALS AND METHODS

Prostate 3-T MRI studies, reports, and clinical data from 623 patients (age 67.9 ± 8.2 years) were retrospectively analyzed and re-evaluated for the presence of EPFs and their clinical significance: E1-no finding or findings that have no clinical significance; E2-potentially significant findings; and E3-significant findings.

RESULTS

Secondary reading identified 1236 EPFs in 593 patients (1.98 ± 1.13 EPFs per patient, no EPFs in 30 patients), from which 468 (37.8%) were mentioned in the original report. The most common findings included diverticulosis (44% of patients), hydrocele (34%), inguinal fat hernia (16%), and bladder wall trabecular hypertrophy (15%). There were 80 (6.5%) E2 EPFs and 30 (2.4%) E3 EPFs. From E3 EPFs, 10 (33%) were not originally reported. A workup was suggested in 35 (52%) of the 67 originally reported E2 and E3 findings with follow-up and performed in 20 (30%). Fourteen (21%) EPFs in 11 patients influenced their management. Four experienced radiologists originally reported 1.8 to 2.5 findings per patient (p < 0.0001).

CONCLUSIONS

EPFs on prostate MRI are frequent, but only 2.4% are clinically significant (E3), and 33% of these are not reported. Only 30% of E2 and E3 findings are further explored, and 21% influence patient management. We suggest that an "E" category should be attached to the PI-RADS system to identify the presence of EPFs that require further workup.

CRITICAL RELEVANCE STATEMENT

Extraprostatic findings on prostate MRI are frequent, but only 2.4% are clinically significant (E3), and 33% of these are not reported. We advocate standardized reporting of extraprostatic findings indicating their clinical significance.

KEY POINTS

• Extraprostatic findings on prostate MRI are frequent with an average of two findings per patient. • 2.4% of extraprostatic findings are significant, and 33% of these are not reported. • There is a significant variability among experienced radiologists in reporting extraprostatic findings.

Genetic Variants in Matrix Metalloproteinases MMP3 (rs3025058) and MMP9 (rs3918242) Associated with Colonic Diverticulosis

Background and Objectives: Diverticulosis affects a significant portion of the elderly population, with age and lifestyle being established risk factors. Additionally, genetic predisposition is gaining recognition as a contributing factor. This pilot study sought to explore the frequency of genetic variants in matrix metalloproteinases (MMPs) 3, 9, and 12 in a population of colonic diverticulosis patients. Materials and Methods: The study encompassed 134 participants: 59 diagnosed with colon diverticulosis during colonoscopy and 75 healthy controls. The cases and controls were meticulously matched in terms of age and gender. We assessed the distribution of genetic variants MMP3 rs3025058, MMP9 rs3918242, and MMP12 rs2276109 using the polymerase chain reaction-restriction fragments length polymorphism technique. Results: The MMP9 rs3918242 allele T was notably more frequent in individuals with diverticulosis when compared with the control group (p < 0.03). Furthermore, it was associated with dominant (OR = 2.62; 95% CI: 1.24-5.56; p < 0.01) and co-dominant (OR = 2.10; 95% CI: 1.06-4.13; p < 0.03) genetic models. The MMP3 rs3025058 5A/5A genotype was nearly twice as frequent in patients with diverticulosis, while the 6A/6A genotype was only half as common in this group. Conversely, no significant correlation was established between MMP12 rs2276109 and colonic diverticulosis. Conclusions: Our study offers the first insight into a potential connection between genetic variants in MMPs and colon diverticulosis. Specifically, allele T of MMP9 rs3918242 and allele 5A of MMP3 rs3025058 appear to be linked to this condition. These findings indirectly suggest a role for extracellular matrix proteins in the pathogenesis of diverticulosis.

Colonic diverticular bleeding: An update on pathogenesis and management

Colonic diverticular bleeding is the most common cause of lower gastrointestinal (GI) bleeding, which can be life-threatening and frequently recurrent. In recent years, the prevalence of diverticulosis has increased in developed countries, with a documented incidence of 50% in patients older than 60 years. Based on the evidence, the use of anticoagulants and/or antiplatelets in the elderly population has resulted in an increased incidence of acute diverticular bleeding. According to the literature, about 50% of patients with diverticular bleeding require a blood transfusion, and 18% - 53% need emergency surgery. Although endoscopic identification of the culprit diverticula and appropriate intervention is a challenge, the newer treatment modality, over-the-scope clip method (OTSC) has been demonstrated to be an effective endoscopic hemostatic method in severe diverticular bleeding, especially in cases of rebleeding after first-line conventional endoscopic procedures. In this review, we summarize the pathophysiology of colonic diverticulosis and diverticular bleeding, recent evidence in its management, and existing theories on various preventive strategies to control diverticular bleeding. We also discuss the efficacy and treatment outcome of the OTSC technique in controlling diverticular bleeding.

150 risk variants for diverticular disease of intestine prioritize cell types and enable polygenic prediction of disease susceptibility

We conducted a genome-wide association study (GWAS) analysis of diverticular disease (DivD) of intestine within 724,372 individuals and identified 150 independent genome-wide significant DNA variants. Integration of the GWAS results with human gut single-cell RNA sequencing data implicated gut myocyte, mesothelial and stromal cells, and enteric neurons and glia in DivD development. Ninety-five genes were prioritized based on multiple lines of evidence, including SLC9A3, a drug target gene of tenapanor used for the treatment of the constipation subtype of irritable bowel syndrome. A DivD polygenic score (PGS) enables effective risk prediction (area under the curve [AUC], 0.688; 95% confidence interval [CI], 0.645-0.732) and the top 20% PGS was associated with ∼3.6-fold increased DivD risk relative to the remaining population. Our statistical and bioinformatic analyses suggest that the mechanism of DivD is through colon structure, gut motility, gastrointestinal mucus, and ionic homeostasis. Our analyses reinforce the link between gastrointestinal disorders and the enteric nervous system through genetics.

Multi-ancestry genome- and phenome-wide association studies of diverticular disease in electronic health records with natural language processing enriched phenotyping algorithm

OBJECTIVE

Diverticular disease (DD) is one of the most prevalent conditions encountered by gastroenterologists, affecting ~50% of Americans before the age of 60. Our aim was to identify genetic risk variants and clinical phenotypes associated with DD, leveraging multiple electronic health record (EHR) data sources of 91,166 multi-ancestry participants with a Natural Language Processing (NLP) technique.

MATERIALS AND METHODS

We developed a NLP-enriched phenotyping algorithm that incorporated colonoscopy or abdominal imaging reports to identify patients with diverticulosis and diverticulitis from multicenter EHRs. We performed genome-wide association studies (GWAS) of DD in European, African and multi-ancestry participants, followed by phenome-wide association studies (PheWAS) of the risk variants to identify their potential comorbid/pleiotropic effects in clinical phenotypes.

RESULTS

Our developed algorithm showed a significant improvement in patient classification performance for DD analysis (algorithm PPVs ≥ 0.94), with up to a 3.5 fold increase in terms of the number of identified patients than the traditional method. Ancestry-stratified analyses of diverticulosis and diverticulitis of the identified subjects replicated the well-established associations between ARHGAP15 loci with DD, showing overall intensified GWAS signals in diverticulitis patients compared to diverticulosis patients. Our PheWAS analyses identified significant associations between the DD GWAS variants and circulatory system, genitourinary, and neoplastic EHR phenotypes.

DISCUSSION

As the first multi-ancestry GWAS-PheWAS study, we showcased that heterogenous EHR data can be mapped through an integrative analytical pipeline and reveal significant genotype-phenotype associations with clinical interpretation.

CONCLUSION

A systematic framework to process unstructured EHR data with NLP could advance a deep and scalable phenotyping for better patient identification and facilitate etiological investigation of a disease with multilayered data.

Dose-dependent reduction of lymphocyte count and heart rate after multiple administration of LC51-0255, a novel sphingosine-1-phosphate receptor 1 modulator, in healthy subjects

Aim: Sphingosine-1-phosphate receptor mediates the egress of lymphocytes from lymphoid organs, and its inhibition results in a decreased number of circulating lymphocytes. The aim of the current study was to investigate the safety and pharmacodynamic and pharmacokinetic characteristics of a novel sphingosine-1-phosphate receptor modulator, LC51-0255.

Methods: A phase 1 randomized, double-blind, placebo-controlled, multiple dosing, dose-escalation study was conducted on healthy Korean male subjects.

Results: After single and daily administration of LC51-0255 for 21 days, a dose-dependent decrease in lymphocyte count and heart rate was observed through 0.25–2 mg dose range of LC51-0255. The mean elimination half-life of LC51-0255 was 76–95 h. LC51-0255 was accumulated with a mean accumulation ratio of 5.17–6.64. During the study, LC51-0255 was generally well tolerated. The most common treatment-emergent adverse event was bradycardia. No clinically significant event of arrhythmia, including AV block, was observed. No clinically significant difference in blood pressure was observed between the dose groups. In other safety assessments, no clinically significant abnormalities were observed, except for bradycardia.

Conclusion: Daily administration of LC51-0255 in the range of 0.25–2 mg resulted in a dose-dependent reduction of lymphocyte counts and heart rate. LC51-0255 is generally safe and well tolerated in healthy volunteers.

Right-sided diverticulitis in a Western population

BACKGROUND

While left-sided colonic diverticular disease is common in Western Caucasian populations, right-sided colonic disease (RCD) is rare. The present study aimed to determine the rate of RCD and to identify the symptoms, clinical features, treatment, and outcomes in a single medical center in Israel.

METHODS

Data for this descriptive retrospective analysis were collected from the electronic medical records of all patients diagnosed with colonic diverticulitis from January 2014 to June 2019.

RESULTS

During the study period, 1000 patients with diverticulitis were admitted to our institution, of which 99 had RCD (10%). Mean age was 50.2 years. The main presenting symptom was acute onset of right-sided abdominal pain. The diagnosis was made almost exclusively by computed tomography scan and the cecum was the most frequent site. The clinical course was benign, without major complications for most patients (90.1%). Nine patients presented with abscess (n = 1), covered perforation (n = 7), or partial obstruction (n = 1). All patients were treated with intravenous antibiotics with a median length of hospital stay of 3 days and a median 9 days of antibiotic treatment. Only 1 patient underwent diagnostic laparoscopy due to suspected intestinal perforation. Three patients experienced disease recurrence after a median follow-up of 48 months. Upon recovery, half of the patients underwent colonoscopy; no further pathology was found in any.

CONCLUSION

Unlike sigmoid colon diverticulitis, the incidence of RCD in Western populations is low. The clinical course is benign, with conservative treatment without the need for surgery. The complication and recurrence rates are low.

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.

The Epidemiology and Etiology of Right-Sided Colonic Diverticulosis: A Review

Diverticulosis of the colon is a common condition in Western countries and most patients will remain asymptomatic, but some will present with symptoms of acute diverticulitis or bleeding. Our understanding of diverticulosis is evolving but is mostly derived from diverticulosis affecting the left-sided colon. In contrast, right-sided colonic diverticulosis (RCD) is more commonly seen in Asian countries but is much less common overall. Based on the marked differences in epidemiology, it is commonly thought that these are 2 distinct disease processes. A review of the literature describing the epidemiology and etiology of RCD was performed, with a comparison to the current understanding of left-sided diverticulosis. RCD is becoming increasingly common. The epidemiology of RCD shows it to be a mostly acquired condition, and not congenital as previously thought. Many factors in the etiology of RCD are similar to that seen in left-sided diverticulosis, with a few variations. It is therefore likely that most cases of RCD represent the same disease process that is seen in the left colon.

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.

Meta-analysis of the demographic and prognostic significance of right-sided versus left-sided acute diverticulitis

AIM

The aim of this work was to compare demographic factors, outcomes and prognosis for right-sided versus left-sided acute colonic diverticulitis.

METHOD

We searched MEDLINE, CINAHL, EMBASE, CENTRAL, Scopus and unpublished literature to identify all observational studies comparing demographic factors and outcomes of right-sided versus left-sided acute colonic diverticulitis (PROSPERO registration number CRD42020180075). We used the QUIPS tool to assess the risk of bias of included studies. Random effects modelling was applied to calculate pooled outcome data.

RESULTS

Analysis of 2933 patients from nine studies suggests that right-sided diverticulitis affects younger patients [mean difference (MD)  -14.16 (-17.19, -11.14), P < 0.00001] and more male patients [odds ratio (OR) 1.33 (1.04, 1.71), P = 0.02] compared with left-sided diverticulitis. Smoking [OR 2.23 (1.50, 3.32), P < 0.0001], alcohol consumption [OR 1.85 (1.26, 2.71), P = 0.002] and comorbidity [OR 0.21 (0.15, 0.30), P < 0.00001] were more common in patients with right-sided diverticulitis. The risk of complicated diverticulitis was lower in the right-sided group [OR 0.21 (0.08, 0.55), P = 0.001]. More patients in the right-sided diverticulitis group had modified Hinchey Stage I disease [OR 10.21 (3.34, 31.22), P < 0.0001] while more patients in the left-sided group had Stage II [OR 0.19 (0.10, 0.38), P < 0.00001], Stage III [OR 0.08 (0.01, 0.54), P = 0.009] or Stage IV disease [OR 0.02 (0.00, 0.08), P < 0.00001]. Right-sided diverticulitis was associated with a lower risk of recurrence [OR 0.49 (0.25, 0.98), P = 0.04], failure of conservative management [OR 0.14 (0.04, 0.43), P = 0.0006], the need for emergency surgery [OR 0.13 (0.05, 0.36), P < 0.00001] and a shorter length of hospital stay [MD -1.70 (-3.08, -0.33), P = 0.02].

CONCLUSION

Right-sided acute diverticulitis predominantly affects younger male patients compared with left-sided disease and is associated with favourable outcomes as indicated by the lower risk of complications, failure of conservative management, need for emergency surgery, recurrence and shorter length of hospital stay. More studies are required to compare the postoperative outcomes in patients with right-sided and left-sided diverticulitis undergoing emergency surgery.

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 Diverticulosis. Is there a Genetic Component?

Diverticular disease is a common condition among the elderly, with a steady increase in prevalence over time. Also, it has a temporal, geographic, and ethnic variation in incidence and prevalence, the genetic component having only recently been studied. For many years, environmental factors were the main link to the etiology. Recent studies estimated the heritability in this disease and identified genetic variants associated with diverticulosis. The interaction between structural changes of the colonic wall, diet, lifestyle, and genetic factors results in the development of diverticular disease. The purpose of this article is to review the existing data about genetic influence in this disease.

Spector T, S. Small K, Steves CJ. Introducing ExHiBITT – Exploring Host microBIome inTeractions in Twins –, a colon multiomic cohort study

Background: The colon is populated by approximately 1012 microorganisms, but the relationships between this microbiome and the host health status are still not completely understood. Here, our objective is to present the cohort characteristics of ExHiBITT – Exploring Host microBIome inTeractions in Twins – including i) biomedical phenotypes, ii) environmental factors and ii) colonoscopic findings. Methods: Participants from the TwinsUK cohort were recruited to study the interactions between the microbiome and host adaptive immunity. In total, 205 monozygotic twins were recruited from the wider TwinsUK cohort. They completed health questionnaires, and provided saliva, blood, colon biopsies from three different locations, caecal fluid, and two faecal samples. Results: A significant proportion of this apparently normal cohort had colonic polyps (28%), which are of interest as potential precursors of colorectal cancer, and, as expected, the number of polyps found was significantly correlated with BMI and age. Hitherto undiagnosed diverticulosis was also not infrequently found during colonoscopy (26%) and was associated with changes in Hybrid Th1-17 cells in the colon. Twin proband co-occurrence rate for diverticulosis (82%) was much higher than for polyps (42%). Familial factors affecting morphology or tolerance may contribute to the ease of endoscopy, as both the time to reach the caecum and pain perceived were highly concordant (proband concordance: 85% and 56%, respectively). Conclusions: We found the expected positive relationship between BMI and colonoscopic anomalies such as diverticular disease and polyps in the whole population, but within twin pairs this association was reversed. This suggests that familial factors confound these associations. Host and microbial next generation sequencing and metabolomics of the samples collected are planned in this cohort.

Diverticular disease epidemiology: acute hospitalisations are growing fastest in young men

BACKGROUND

Older age has long been linked to risk of diverticulitis, but the epidemiology is seldom described for a national population. The aim of this study was to investigate age- and gender differences in incidence, temporal trends, lifetime risk and prevalence related to acute diverticulitis hospitalisations in New Zealand.

METHODS

Records of all hospitalisations with diverticulitis the primary diagnosis were obtained from the Ministry of Health for the period 2000-2015. The first acute diverticulitis admission recorded for an individual was taken as an incident event; all others were classified as recurrent. Trends in age- and sex-specific and age-standardised incidence rates are described, and lifetime risk and prevalence estimated.

RESULTS

Over the 16 years from 2000 to 2015, 37,234 acute hospitalisations for diverticulitis were recorded in 28,329 people aged 30 + years (median = 66 years). Rates of incident hospitalisations rose with age, from 5/10,000 person-years at age 50-54 years to 19/10,000py by age 80-84 years. Rates for women were lower than men before age 55 years, but higher thereafter. Age-standardised rates rose 0.2/10,000py annually, but approximately doubled among men aged < 50 years. Lifetime risk was estimated at over 5%, with the prevalence pool rising to over 1.5% of the population aged 30+ in 2030.

CONCLUSIONS

Rapid increases in diverticulitis admissions among young men since 2000 correspond with increases reported elsewhere but remain unexplained; notably young women follow similar trends 5-10 years later. Increasing incidence, combined with population ageing, adds urgency to explain diverticular formation, to understand factors that trigger or provoke their inflammation/infection, and to clarify treatment and (self-)management pathways.

Etiopathogenetic Mechanisms in Diverticular Disease of the Colon

This article reviews epidemiological evidence of heritability and putative mechanisms in diverticular disease, with greatest attention to 3 recent studies of genetic associations with diverticular disease based on genome-wide or whole-genome sequencing studies in large patient cohorts. We provide an analysis of the biological plausibility of the significant associations with gene variants reported and highlight the relevance of ANO1, CPI-17 (aka PPP1R14A), COLQ6, COL6A1, CALCB or CALCA, COL6A1, ARHGAP15, and S100A10 to colonic neuromuscular function and tissue properties that may result in altered compliance and predispose to the development of diverticular disease. Such studies also identify candidate genes for future studies.

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.

Clinical presentation and outcomes of acute diverticulitis in a Middle Eastern population

BACKGROUND AND STUDY AIMS

There is lack of literature describing the presentation of diverticulitis in the Middle East population. The aim of this study is to provide an analysis of the epidemiological indicators, patterns of presentation and outcomes of acute diverticulitis in a Middle Eastern population.

PATIENTS AND METHODS

A retrospective review of all adult patients over the age of 17 who were admitted to the surgical service with a diagnosis of acute diverticulitis between January 2010 and May 2018 at a major university affiliated government hospital in the state of Kuwait. Data collected included patients' demographics, clinical presentation, management and outcome.

RESULTS

Between January 2010 and May 2018 there were 132 patients admitted with a diagnosis of acute diverticulitis. The mean age was 49.2 [±14.3] years. There were 89 (67.4%) men and 43 (32.6%) women. One-hundred and fifteen patients (87.1%) were Arabs, of which Kuwaiti citizens represented 58.3%. Most patients (76.5%) presented with uncomplicated diverticulitis. One hundred and twelve patients (84.8%) had sigmoid colon diverticulitis. There were nine patients that were readmitted within thirty days. The mean length of hospital stay was 5.3 days [±4.5]. The median follow-up period was 15.6 weeks (IQR 1.8, 118.4), during which time recurrent attacks occurred in 25 patients (18.9%).

CONCLUSIONS

It appears that there is a low prevalence of acute diverticulitis in Arabs living in Kuwait, and that when they do present with acute diverticulitis the majority present at a relatively younger age with uncomplicated disease.

Genome-wide association study of right-sided colonic diverticulosis in a Korean population

Diverticulosis results from complex interactions related to aging, environmental factors and genetic predisposition. Despite epidemiologic evidence of genetic risk factors, there has been no attempt to identify genes that confer susceptibility to colonic diverticulosis. We performed the first genome-wide association study (GWAS) on susceptibility to diverticulosis in a Korean population. A GWAS was carried out in 7,948 healthy individuals: 893 patients and 1,075 controls comprised the test set, and 346 patients and 305 controls comprised the replication set. Diverticulosis was diagnosed by colonoscopy during comprehensive medical check-ups, and single-nucleotide polymorphisms (SNPs) related to diverticulosis were detected with the Affymetrix Axiom KORV1.1-96 Array. In all, 9 SNPs were identified in three SNP aggregates in the test set (P < 10⁻³, within 200 kb) after adjusting for sex. All the SNPs were replicated in the replication set (P < 0.05). Three SNPs were near the WNT4 gene, four near the RHOU gene, and two in the OAS1/3 genes. The top SNP associated with right-sided colonic diverticulosis was rs22538787, located near the WNT4 gene [combined set, P-value = 3.128 × 10⁻⁶, odds ratio = 1.415 (95% confidence interval: 1.223–1.637)]. These 9 novel SNP alleles associated with the WNT4, RHOU, and OAS1/3 genes are possibly involved in the underlying genetic susceptibility to right-sided diverticulosis. Our results provide basic knowledge about the development of diverticulosis in an Asian population.

The Mexican consensus on the diagnosis and treatment of diverticular disease of the colon

Since the publication of the 2008 guidelines on the diagnosis and treatment of diverticular disease of the colon by the Asociación Mexicana de Gastroenterología, significant advances have been made in the knowledge of that disease. A systematic review of articles published in the medical literature from January 2008 to July 2018 was carried out to revise and update the 2008 guidelines and provide new evidence-based recommendations. All high-quality articles in Spanish and English published within that time frame were included. The final versions of the 43 statements accepted in the three rounds of voting, utilizing the Delphi method, were written, and the quality of evidence and strength of the recommendations were established for each statement, utilizing the GRADE system. The present consensus contains new data on the definition, classification, epidemiology, pathophysiology, and risk factors of diverticular disease of the colon. Special emphasis is given to the usefulness of computed tomography and colonoscopy, as well as to the endoscopic methods for controlling bleeding. Outpatient treatment of uncomplicated diverticulitis is discussed, as well as the role of rifaximin and mesalazine in the management of complicated acute diverticulitis. Both its minimally invasive alternatives and surgical options are described, stressing their indications, limitations, and contraindications. The new statements provide guidelines based on updated scientific evidence. Each statement is discussed, and its quality of evidence and the strength of the recommendation are presented.

Maternal Uniparental Disomy 14 (UPD14) Identified by Clinical Exome Sequencing in an Adolescent with Diverticulosis

Pediatric diverticular disease is extremely rare, with most cases associated with connective tissue disorders. We report an adolescent boy with syndromic features who presented with acute complicated sigmoid diverticulitis. Clinical exome sequencing analysis detected a 6.5-Mb region of homozygosity on chromosome 14, consistent with partial maternal uniparental disomy. Analysis of this region did not identify rare homozygous variants but included several imprinted genes that were candidates for the observed phenotypes. The pediatric clinical presentation of diverticulosis in this patient has not been previously described in maternal uniparental disomy of chromosome 14 and adds to the phenotypic spectrum of the syndrome.

Irritable bowel syndrome and colonic diverticular disease: overlapping symptoms and overlapping therapeutic approaches

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a common symptomatic disorder in the Western world and colonic diverticula are also prevalent; however, relationships between IBS-type symptoms and diverticula have been a source of much debate. Our goal was to reassess these relationships in the light of new data.

RECENT FINDINGS

On removing from consideration clinical scenarios which are directly related to diverticula (i.e., diverticulitis, diverticular hemorrhage, and complications of diverticulitis, such as stricture and fistula), relationships between IBS and diverticula can be seen to revolve around a number of questions. First, are IBS and symptomatic uncomplicated diverticular disease (SUDD) the same condition? Or, in other words is SUDD no more than IBS in an individual who just happens to have diverticula? Although coincident IBS and diverticula inevitably do occur there is some evidence to indicate that SUDD may be somewhat distinctive with SUDD being characterized by more frequent and severe pain. Second, and analogous to interactions between IBS and inflammatory bowel disease or celiac disease, can an episode of acute diverticulitis lead to the de novo development of IBS? There is now epidemiological and pathophysiological evidence to support this occurrence.

SUMMARY

Although relationships between uncomplicated diverticular disease and IBS have been reexamined their status remains unclear. As yet, however, none of the newer concepts related to this relationship have led to new therapeutic approaches in IBS or diverticular disease.

Risk of colorectal cancer in patients with diverticular disease

Colorectal cancer constitutes an important burden on the healthcare system. Screening at-risk populations to reduce colorectal cancer-related morbidity and mortality has become part of good clinical practice. However, recommendations regarding subgroups of patients with diverticular disease are subject to controversy.

Herein, we review the most recent literature regarding the prevalence of colorectal cancer in patients with diverticular disease, diverticulitis and uncomplicated diverticulitis.

The recent literature does not identify diverticular disease as a long-term risk factor for colorectal cancer. However, the risk of colorectal cancer is increased in the short-term period after hospitalization related to diverticular disease. According to a recent systematic review and meta-analysis, the prevalence of colorectal cancer is 1.6% in patients with acute diverticulitis who underwent colonoscopy. The risk of having colorectal cancer after an episode of acute diverticulitis is 44-fold higher than that of an age- and gender-adjusted reference population. Despite lower among patients with uncomplicated episode, the risk of colorectal cancer remains 40-fold higher in that subpopulation than that in the reference population.

To conclude, the recent literature describes an increased risk of colorectal cancer among patients with acute diverticulitis compared to the reference population. Colonoscopy is therefore recommended in patients with diverticulitis to exclude colorectal cancer.

Alterations in enteric calcitonin gene-related peptide in patients with colonic diverticular disease: CGRP in diverticular disease

Diverticular disease (DD) is one of the most prevalent diseases of the large bowel. Lately, imbalance of neuro-muscular transmission has been recognized as a major etiological factor for DD. Neuronal calcitonin gene-related peptide (CGRP) is a potent gastrointestinal smooth muscle relaxant shown to have a widespread effect within the alimentary tract. Nevertheless, CGRPergic innervation of the enteric ganglia has never been considered in the context of motility impairment observed in DD patients. Changes in CGRP and calcitonin receptor-like receptor (CRLR) abundance within enteric ganglia were investigated in sigmoid samples from symptomatic and asymptomatic DD patients using quantitative fluorescence microscopy. CGRP effect on gastrointestinal smooth muscle was investigated using organ bath technique. We found CGRP levels within the enteric ganglia to be declined by up to 52% in symptomatic DD patients. Conversely, CRLR within the enteric ganglia was upregulated by 41% in symptomatic DD. Longitudinal smooth muscle displayed an elevated (+10.5%) relaxant effect to the exogenous application of CGRP in colonic strips from symptomatic DD patients. Samples from asymptomatic DD patients consistently showed intermediate values across different experiments. In conclusion, the present study demonstrates that CGRPergic signaling is subject to alteration in DD. Our results suggest that a hypersensitization mechanism to gradually decreasing levels of CGRP-IR nerve fibers takes place during DD progression. Alterations to CGRPergic signaling in DD disease may have implications for physiological abnormalities associated with colonic DD.

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.

Evidence for Dietary Fibre Modification in the Recovery and Prevention of Reoccurrence of Acute, Uncomplicated Diverticulitis: A Systematic Literature Review

In practice, nutrition recommendations vary widely for inpatient and discharge management of acute, uncomplicated diverticulitis. This systematic review aims to review the evidence and develop recommendations for dietary fibre modifications, either alone or alongside probiotics or antibiotics, versus any comparator in adults in any setting with or recently recovered from acute, uncomplicated diverticulitis. Intervention and observational studies in any language were located using four databases until March 2017. The Cochrane Risk of Bias tool and GRADE were used to evaluate the overall quality of the evidence and to develop recommendations. Eight studies were included. There was "very low" quality evidence for comparing a liberalised and restricted fibre diet for inpatient management to improve hospital length of stay, recovery, gastrointestinal symptoms and reoccurrence. There was "very low" quality of evidence for using a high dietary fibre diet as opposed to a standard or low dietary fibre diet following resolution of an acute episode, to improve reoccurrence and gastrointestinal symptoms. The results of this systematic review and GRADE assessment conditionally recommend the use of liberalised diets as opposed to dietary restrictions for adults with acute, uncomplicated diverticulitis. It also strongly recommends a high dietary fibre diet aligning with dietary guidelines, with or without dietary fibre supplementation, after the acute episode has resolved.

Sex differences in risk factors of uncomplicated colonic diverticulosis in a metropolitan area from Northern China

As the world’s most populated and rapidly aging country, there is limited information on sex-related differences in factors regarding uncomplicated colonic diverticulosis in China. We aimed to investigate sex differences in individual risk factor in a northern metropolis. Patients with colonic diverticulosis who underwent indicated colonoscopy were queried with respect to medical history and demographic features. Demographic information, life style factors and co-morbidities were retrieved from a prospective dataset. Multiple regression analyses were performed to determine precipitating factors of diverticula. Of 4,386 enrolled patients, colonic diverticulosis were detected in 218 cases (4.97%). Multiple logistic regression analysis implicated increasing age (OR = 1.05, 95%CI 1.03–1.06, P < 0.001), red meat ≥100 g/d (OR = 2.53, 95%CI 1.72–3.70, P < 0.001), smoking (OR = 2.14, 95%CI 1.05–4.33, P = 0.035), rheumatologic diseases (OR = 3.38, 95%CI 1.09–10.5, P = 0.035) and NSAIDs (OR = 2.11, 95%CI 1.12–3.97, P = 0.020) were significantly associated with diverticulosis in men, whilst advancing age (OR = 1.03, 95%CI 1.01–1.05, P = 0.013), BMI (OR = 1.12, 95%CI 1.04–1.19, P = 0.001), smoking (OR = 10.2, 95%CI 2.81–37.4, P < 0.001), rheumatologic diseases (OR = 8.04, 95%CI 3.05–21.2, P < 0.001), hypertension (OR = 1.76, 95%CI 1.01–3.06, P = 0.047), colonic polyps (OR = 3.12, 95%CI 1.82–5.36, P < 0.001) and antihypertensive medications (OR = 2.99, 95%CI 1.66–5.39, P < 0.001) in women. In conclusion, it is pivotal to take account of differentially sex-related factors in regard to the development of uncomplicated colonic diverticulosis.

Colonic diverticulosis is not a risk factor for colonic adenoma

BACKGROUND AND AIMS

Colonic diverticulosis may represent a risk factor for colonic adenomas by virtue of the fact that evolving data suggest that these 2 conditions may share common risk factors such as Western dietary pattern and physical inactivity. This study aims to investigate the association between colonic diverticulosis and colonic adenomas in mainland China.

METHODS

We conducted a cross-sectional study on patients who underwent colonoscopic examination between October 2013 and December 2014 in a university hospital in mainland China. Age, gender, colonic adenomas, advanced adenomas, and distribution of diverticulosis were recorded during the procedures. Multivariate logistic regression and stratified analysis were used to evaluate the associations between the prevalence of diverticulosis and age, sex, and presence of colonic adenomas and advanced adenomas.

RESULTS

A total of 17,456 subjects were enrolled. The prevalence of colonic diverticulosis and adenoma was 2.4% and 13.2%, respectively. With regard to distribution of diverticula, most (365/424, 86.1%) were right-sided. Multiple logistic regression analysis suggested that age and male gender were independent risk factors for adenoma and advanced adenoma. There was no relationship between diverticulosis or location of diverticulosis and presence of adenoma and advanced adenoma adjusting by age and gender. In a stratified analysis according to age and gender, similar results were also noted.

CONCLUSION

There was no statistical relationship between diverticulosis and the risk of adenoma and advanced adenoma. Our results may not be generalized to the Western population due to the fact that left-sided diverticular cases were very small in our study.

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.

Prevalence of colonic diverticulosis in mainland China from 2004 to 2014

The aim of this study was to determine the prevalence of colonic diverticulosis in mainland China. Sixty two thousand and thirty-four colonoscopies performed between Jan 2004 and Dec 2014 were reviewed retrospectively. The overall diverticulosis prevalence was 1.97% and out of this, 85.3% was right-sided. Prevalence does not change, significantly, on trends between the period 2004-2014. The peak of prevalence of diverticulosis was compared between the female group aged >70 years to the male one of 41-50 years. The other peak, otherwise, was compared between the group of 51-60 years with the right-sided diverticulosis to the one of >70 years with left-sided disease. Multivariate analysis suggested that the male gender could be a risk factor for diverticulosis in the group aged ≤70 years, but not for the older patients. In addition, among men was registered an increased risk factor for right-sided diverticulosis and, at the same time, a protective one for left-sided localization. In conclusion, the prevalence of colonic diverticulosis is very low in mainland China and it does not change significantly on trends over the time. Both the prevalence of this condition and its distribution changes according to the age and the genders. These findings may lead the researchers to investigate the mechanisms causing this kind of disease and its distribution in regard of the age and the gender.