Distinct changes in the colonic microbiome associated with acute diverticulitis

Visceral Fat Quantified by a Fully Automated Deep-Learning Algorithm and Risk of Incident and Recurrent Diverticulitis

BACKGROUND

Obesity is a risk factor for diverticulitis. However, it remains unclear whether visceral fat area, a more precise measurement of abdominal fat, is associated with the risk of diverticulitis.

OBJECTIVE

To estimate the risk of incident and recurrent diverticulitis according to visceral fat area.

DESIGN

A retrospective cohort study.

SETTINGS

The Mass General Brigham Biobank.

PATIENTS

A total of 6654 patients who underwent abdominal CT for clinical indications and had no diagnosis of diverticulitis, IBD, or cancer before the scan were included.

MAIN OUTCOME MEASURES

Visceral fat area, subcutaneous fat area, and skeletal muscle area were quantified using a deep-learning model applied to abdominal CT. The main exposures were z -scores of body composition metrics normalized by age, sex, and race. Diverticulitis cases were identified using the International Classification of Diseases codes for the primary or admitting diagnosis from the electronic health records. The risks of incident diverticulitis, complicated diverticulitis, and recurrent diverticulitis requiring hospitalization according to quartiles of body composition metrics z -scores were estimated.

RESULTS

A higher visceral fat area z -score was associated with an increased risk of incident diverticulitis (multivariable HR comparing the highest vs lowest quartile, 2.09; 95% CI, 1.48-2.95; p for trend <0.0001), complicated diverticulitis (HR, 2.56; 95% CI, 1.10-5.99; p for trend = 0.02), and recurrence requiring hospitalization (HR, 2.76; 95% CI, 1.15-6.62; p for trend = 0.03). The association between visceral fat area and diverticulitis was not materially different among different strata of BMI. Subcutaneous fat area and skeletal muscle area were not significantly associated with diverticulitis.

LIMITATIONS

The study population was limited to individuals who underwent CT scans for medical indication.

CONCLUSIONS

Higher visceral fat area derived from CT was associated with incident and recurrent diverticulitis. Our findings provide insight into the underlying pathophysiology of diverticulitis and may have implications for preventive strategies. See Video Abstract .

GRASA VISCERAL CUANTIFICADA MEDIANTE UN ALGORITMO DE APRENDIZAJE PROFUNDO TOTALMENTE AUTOMATIZADO Y RIESGO DE DIVERTICULITIS RECURRENTE E INCIDENTAL

ANTECEDENTES:La obesidad es un factor de riesgo de la diverticulitis. Sin embargo, sigue sin estar claro si el área de grasa visceral, con medida más precisa de la grasa abdominal esté asociada con el riesgo de diverticulitis.OBJETIVO:Estimar el riesgo de diverticulitis incidente y recurrente de acuerdo con el área de grasa visceral.DISEÑO:Un estudio de cohorte retrospectivo.AJUSTE:El Biobanco Mass General Brigham.PACIENTES:6.654 pacientes sometidos a una TC abdominal por indicaciones clínicas y sin diagnóstico de diverticulitis, enfermedad inflamatoria intestinal o cáncer antes de la exploración.PRINCIPALES MEDIDAS DE RESULTADOS:Se cuantificaron, área de grasa visceral, área de grasa subcutánea y área de músculo esquelético, utilizando un modelo de aprendizaje profundo aplicado a la TC abdominal. Las principales exposiciones fueron puntuaciones z de métricas de composición corporal, normalizadas por edad, sexo y raza. Los casos de diverticulitis se definieron con los códigos ICD para el diagnóstico primario o de admisión de los registros de salud electrónicos. Se estimaron los riesgos de diverticulitis incidente, diverticulitis complicada y diverticulitis recurrente que requiriera hospitalización según los cuartiles de las puntuaciones z de las métricas de composición corporal.RESULTADOS:Una puntuación z más alta del área de grasa visceral se asoció con un mayor riesgo de diverticulitis incidente (HR multivariable que compara el cuartil más alto con el más bajo, 2,09; IC del 95 %, 1,48-2,95; P para la tendencia < 0,0001), diverticulitis complicada (HR, 2,56; IC del 95 %, 1,10-5,99; P para la tendencia = 0,02) y recurrencia que requiriera hospitalización (HR, 2,76; IC del 95 %, 1,15-6,62; P para la tendencia = 0,03). La asociación entre el área de grasa visceral y la diverticulitis no fue materialmente diferente entre los diferentes estratos del índice de masa corporal. El área de grasa subcutánea y el área del músculo esquelético no se asociaron significativamente con la diverticulitis.LIMITACIONES:La población del estudio se limitó a individuos sometidos a tomografías computarizadas por indicación médica.CONCLUSIÓN:Una mayor área de grasa visceral derivada de la tomografía computarizada se asoció con diverticulitis incidente y recurrente. Nuestros hallazgos brindan información sobre la fisiopatología subyacente de la diverticulitis y pueden tener implicaciones para las estrategias preventivas. (Traducción: Dr. Fidel Ruiz Healy ).

Metatranscriptomic analysis of colonic mucosal samples exploring the functional role of active microbial consortia in complicated diverticulitis

In this study, we investigated complicated diverticulitis, an inflammatory condition associated with abscesses, fistulas, intestinal obstructions, perforations, and primarily affects adults over the age of 60. Although the exact etiology remains unclear, the gut microbiome has been suggested as a contributing factor. Previous studies have used 16S rRNA gene analysis from patient fecal samples, which is limited to identifying the bacterial communities present. Herein, we employed shotgun metatranscriptomics on 40 patient-matched samples of diseased and adjacent normal colonic mucosal tissues from 20 patients with complicated diverticulitis to gain a more comprehensive understanding of active microbial taxa and gene expression patterns that may be involved in this disease state. Our findings revealed distinct beta diversity and a conglomerate of pathogenic microbiota in the diseased tissues, including Staphylococcus cohnii, Corynebacterium jeikeium, Kineococcus, Talaromyces rugulosus, Campylobacteraceae, and Ottowia, among others. The adjacent normal tissues were a stark contrast, harboring anti-inflammatory taxa such as Streptococcus salivarius and housekeeping genes and pathways such as the ABC-2 type transport system ATP-binding protein. These results align with previous amplicon sequencing studies and provide novel functional insights that may be crucial for understanding the etiology of complicated diverticulitis.IMPORTANCEComplicated diverticulitis is a virulent condition with no clear cause other than the association with colonic diverticulosis. We assessed the microbial gene expression in complicated diverticulitis patients using colonic tissue samples, revealing microbes in the diseased tissue known to exacerbate the diverticular condition and to live in extreme places, and microbes in patients' normal tissue known to maintain normal bodily functions. This functional information is therefore important for understanding what microbial taxa are present and what they are doing. It is possible clinicians could someday harness this information to more effectively treat complicated diverticulitis symptoms. For example, clinicians may suggest dietary changes and prescribe probiotics to increase beneficial bacteria. Clinicians may also prescribe targeted antibiotics or consider the emerging treatment option of fecal transplants in complicated diverticulitis patients. While not curing complicated diverticulitis, each potential treatment option mentioned addresses balancing out dysbiosis of the gut microbiome, therefore alleviating associated symptoms.

Safety and efficacy of faecal microbiota transplantation in patients with acute uncomplicated diverticulitis: study protocol for a randomised placebo-controlled trial

Background

Little is known about the involvement of gut microbiota in the disease course of diverticulitis and the potential benefits of manipulating the gut milieu. We propose to conduct a randomised placebo-controlled feasibility trial of faecal microbiota transplantation (FMT) given as capsules to patients with acute uncomplicated diverticulitis.

Objectives

The objective is primarily to investigate the feasibility of clinical safety, explore efficacy associated with FMT in this patient population, and examine changes in patient-reported quality of life and the composition and function of the gut microbiota.

Design

Study protocol for a randomised placebo-controlled trial.

Methods and analysis

Participants with acute, uncomplicated diverticulitis, as confirmed by computed tomography (CT) scan, will be recruited from Odense University Hospital (Denmark) and randomly assigned to either the intervention group or the control group. The intervention group will consist of 20 patients who receive encapsulated FMT. The control group will also consist of 20 patients, receiving placebo capsules. Primary safety endpoint: Patient safety is monitored by (a) the number of re-admissions and (b) the number of adverse events within 3 months of FMT/placebo; Primary efficacy endpoint: Reduction in the proportion of patients treated with antibiotics within 3 months following FMT/placebo; Secondary outcome: Change from baseline to 3 months in the GI-QLI questionnaire. Results will be analysed using an intention-to-treat approach. Adverse events or unintended consequences will be reported.

Ethics and discussion

This is the first study to investigate the safety and efficacy of FMT in patients with acute uncomplicated diverticulitis. The project has the potential to broaden the knowledge and literature on the role of the intestinal microbiota in diverticulitis, and we believe it will elevate our understanding of cause and effect.

Trial registration

Informed consent is obtained from all participants. The study is approved by the regional ethics committee (ref. S-20230023) and the Danish Data Protection Agency (ref. 24/2435). The trial was registered on clinicaltrials.gov (NCT06254625) on 10th February 2024.

The role of gut microbiota in the pathogenesis of diverticular disease: where are we now?

Diverticular disease (DD) is widespread worldwide. The role of gut microbiota (GM) in DD is not entirely understood.  Here we discuss the significance of the current knowledge on GM in the different stages of DD and how crucial these acquisitions are for designing diagnostic and therapeutic trials in this field.

Deciphering the gut microbiota's role in diverticular disease: insights from a Mendelian randomization study

Background

Previous studies have indicated a potential association between gut microbiota and diverticular disease. However, the precise nature of this relationship remains unclear. In light of this, we decided to use a bidirectional two-sample Mendelian randomization (MR) study to investigate the causal relationship between gut microbiota and intestinal diverticular disease in greater depth.

Methods

To investigate the potential causal relationship between gut microbiota and intestinal diverticular disease, we conducted a two-sample MR study in a European ancestry. Genetic instrumental variables for gut microbiota were obtained from a genome-wide association study (GWAS) involving 5,959 participants. Summary statistics for intestinal diverticular disease were sourced from the IEU Open GWAS project, which included data from 5,193 cases and 457,740 controls. The analysis was primarily conducted using the inverse variance weighted method, with additional sensitivity analyses to assess the robustness of the findings.

Results

With regard to the findings, 11 microbial taxa were identified as having a potential causal relationship with intestinal diverticular disease. Specifically, the microbial taxa Caryophanales, Paenibacillaceae, Herbinix, Turicibacter, Turicibacteraceae, and Staphylococcus fleurettii were found to be positively associated with the risk of developing intestinal diverticular disease, while Chromatiales, Arcobacter, Herbidospora, Ligilactobacillus ruminis, and Megamonas funiformis were found to be negatively associated with the risk. Further reverse MR analysis did not reveal a reverse causal effect between these microbial taxa and intestinal diverticular disease.

Conclusion

Our MR analyses revealed a potential causal relationship between certain gut microbiota and intestinal diverticular disease, which may provide new directions for future intestinal diverticular disease prevention and treatment strategies.

Diverticular disease and risk of incident major adverse cardiovascular events: A nationwide matched cohort study

BACKGROUND

An increased risk of cardiovascular disease (CVD) has been reported in patients with diverticular disease (DD). However, there are knowledge gaps about specific risks of each major adverse cardiovascular event (MACE) component.

METHODS

This nationwide cohort study included Swedish adults with DD (1987-2017, N=52,468) without previous CVD. DD was defined through ICD codes in the National Patient Register and colorectal histopathology reports from the ESPRESSO study. DD cases were matched by age, sex, calendar year and county of residence to ≤5 population reference individuals (N=194,525). Multivariable-adjusted hazard ratios (aHRs) for MACE up until December 2021 were calculated using stratified Cox proportional hazard models.

RESULTS

Median age at DD diagnosis was 62 years and 61% were females. During a median follow-up of 8.6 years, 16,147 incident MACE occurred in individuals with DD, and 48,134 in reference individuals (incidence rates (IRs)=61.4 vs. 43.8/1,000 person-years) corresponding to an aHR of 1.24 (95%CI=1.22-1.27), equivalent to one extra case of MACE for every 6 DD patients followed for 10 years. The risk was increased for ischemic heart disease (IR=27.9 vs. 18.6; aHR=1.36, 95%CI=1.32-1.40), congestive heart failure (IR=23.2 vs. 15.8; aHR=1.26, 95%CI=1.22-1.31), and stroke (IR=18.0 vs. 13.7; aHR=1.15, 95%CI=1.11-1.19). DD was not associated with cardiovascular mortality (IR=18.9 vs. 15.3; aHR=1.01, 95%CI=0.98-1.05). Results remained robust in sibling-controlled analyses.

CONCLUSIONS

Patients with DD had a 24% increased risk of MACE compared with reference individuals, but no increased cardiovascular mortality. Future research should confirm these data and examine underlying mechanisms and shared risk factors between DD and CVD.

Gut microbiome composition and metabolic activity in women with diverticulitis

The etiopathogenesis of diverticulitis, among the most common gastrointestinal diagnoses, remains largely unknown. By leveraging stool collected within a large prospective cohort, we performed shotgun metagenomic sequencing and untargeted metabolomics profiling among 121 women diagnosed with diverticulitis requiring antibiotics or hospitalizations (cases), matched to 121 women without diverticulitis (controls) according to age and race. Overall microbial community structure and metabolomic profiles differed in diverticulitis cases compared to controls, including enrichment of pro-inflammatory Ruminococcus gnavus, 1,7-dimethyluric acid, and histidine-related metabolites, and depletion of butyrate-producing bacteria and anti-inflammatory ceramides. Through integrated multi-omic analysis, we detected covarying microbial and metabolic features, such as Bilophila wadsworthia and bile acids, specific to diverticulitis. Additionally, we observed that microbial composition modulated the protective association between a prudent fiber-rich diet and diverticulitis. Our findings offer insights into the perturbations in inflammation-related microbial and metabolic signatures associated with diverticulitis, supporting the potential of microbial-based diagnostics and therapeutic targets.

The role of microbiota and its modulation in colonic diverticular disease

BACKGROUND

Diverticular disease (DD) is a common condition in Western countries. The role of microbiota in the pathogenesis of DD and its related symptoms has been frequently postulated since most complications of this disease are bacteria-driven and most therapies rely on microbiota modulation. Preliminary data showed fecal microbial imbalance in patients with DD, particularly when symptomatic, with an increase of pro-inflammatory and potentially pathogenetic bacteria. In addition, bacterial metabolic markers can mirror specific pathways of the disease and may be even used for monitoring treatment effects. All treatments currently suggested for DD can affect microbiota structure and metabolome compositions.

PURPOSE

Sparse evidence is available linking gut microbiota perturbations, diverticular disease pathophysiology, and symptom development. We aimed to summarize the available knowledge on gut microbiota evaluation in diverticular disease, with a focus on symptomatic uncomplicated DD, and the relative treatment strategies.

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.

Infection or Inflammation: Are Uncomplicated Acute Appendicitis, Acute Cholecystitis, and Acute Diverticulitis Infectious Diseases?

Background: It is recognized increasingly that common surgical infections of the peritoneal cavity may be treated with antibiotic agents alone, or source control surgery with short-course antimicrobial therapy. By extension, testable hypotheses have emerged that such infections may not actually be infectious diseases, but rather represent inflammation that can be treated successfully with neither surgery nor antibiotic agents. The aim of this review is to examine extant data to determine which of uncomplicated acute appendicitis (uAA), uncomplicated acute calculous cholecystitis (uACC), or uncomplicated mild acute diverticulitis (umAD) might be amenable to management using supportive therapy alone, consistent with the principles of antimicrobial stewardship. Methods: Review of pertinent English-language literature and expert opinion. Results: Only two small trials have examined whether uAA can be managed with observation and supportive therapy alone, one of which is underpowered and was stopped prematurely because of challenging patient recruitment. Data are insufficient to determine the safety and efficacy of non-antibiotic therapy of uAA. Uncomplicated acute calculous cholecystitis is not primarily an infectious disease; infection is a secondary phenomenon. Even when bactibilia is present, there is no high-quality evidence to suggest that mild disease should be treated with antibiotic agents. There is evidence to indicate that antibiotic prophylaxis is indicated for urgent/emergency cholecystectomy for uACC, but not in the post-operative period. Uncomplicated mild acute diverticulitis, generally Hinchey 1a or 1b in current nomenclature, does not benefit from antimicrobial agents based on multiple clinical studies. The implication is that umAD is inflammatory and not an infectious disease. Non-antimicrobial management is reasonable. Conclusions: Among the considered disease entities, the evidence is strongest that umAD is not an infectious disease and can be treated without antibiotic agents, intermediate regarding uACC, and lacking for uAA. A plausible hypothesis is that these inflammatory conditions are related to disruption of the normal microbiome, resulting in dysbiosis, which is defined as an imbalance of the natural microflora, especially of the gut, that is believed to contribute to a range of conditions of ill health. As for restorative pre- or probiotic therapy to reconstitute the microbiome, no recommendation can be made in terms of treatment, but it is not recommended for prevention of primary or recurrent disease.

Fusobacterium nucleatum Pyogenic Liver Abscess and the Role of Bacterial Virulence and Gut Microbiota Dysbiosis

In the United States, pyogenic liver abscesses are often due to monomicrobial infection and are rarely documented to be a consequence of Fusobacterium infection, a common cause of Lemierre's syndrome. Recent advances in gut microbial studies have identified Fusobacterium as a commensal gut flora that becomes pathogenic in the setting of dysbiosis resulting from colorectal diseases, such as diverticulitis. While the bacteria's tropism for the liver remains to be elucidated, the virulence pattern of Fusobacterium and the portal venous drainage system have allowed us to understand the bacterium's propensity for causing right hepatic abscesses. In this case report, we detail an immunocompetent man with a history of sigmoid diverticulitis who developed a right hepatic abscess due to Fusobacterium nucleatum, while delineating a review of the literature on the virulent properties of the bacterium and the impact of gut microbiota dysbiosis in its pathogenicity. A descriptive analysis was also performed to identify the characteristics of patients who are at risk in hopes of further improving the clinical diagnostic schema for this condition.

Microbiota of the Colonic Diverticula in the Complicated Form of Diverticulitis: A Case Report

Intestinal microbiota appears to be implicated in the pathogenesis of diverticular disease. We present the case of a patient with diverticular colon disease complicated by a pelvic abscess. During the successful surgical treatment, two specimens were taken from the resected colon segment for the microbiota analysis: an inflamed and perforated diverticulum and a diverticulum without signs of inflammation. Culturing and 16S rRNA gene sequencing revealed significant changes in the microbial community structure and composition associated with the acute inflammation and perforation of the colonic diverticulum. The characteristics that are usually associated with the inflammatory process in the gut, namely reduced microbial diversity and richness, decreased Firmicutes-to-Bacteroidetes (F/B) ratio, depletion of butyrate-producing bacteria, and Enterobacteriaceae blooming, were more pronounced in the non-inflamed diverticulum rather than in the adjacent inflamed and perforated one. This is the first study of the intraluminal microbiota of the diverticular pockets, which is more relevant to the etiology of diverticular disease than mucosa-associated microbiota via biopsies and luminal microbiota via fecal samples.

Microbiota Composition in Diverticular Disease: Implications for Therapy

Gut microbiota (GM) composition and its imbalance are crucial in the pathogenesis of several diseases, mainly those affecting the gastrointestinal tract. Colon diverticulosis and its clinical manifestations (diverticular disease, DD) are among the most common digestive disorders in developed countries. In recent literature, the role of GM imbalance in the onset of the different manifestations within the clinical spectrum of DD has been highlighted. This narrative review aims to summarize and critically analyze the current knowledge on GM dysbiosis in diverticulosis and DD by comparing the available data with those found in inflammatory bowel disease (IBD). The rationale for using probiotics to rebalance dysbiosis in DD is also discussed.