Role of visceral fat in colonic inflammation: from Crohn's disease to diverticulitis

The impact of adipose fat tissue on the pathogenesis of crypto-glandular anal fistula

<b>Indroduction:</b> Cryptoglandular perianal fistula represents a prevalent benign anorectal condition, primarily addressed through surgical interventions, occasionally posing considerable therapeutic challenges. The associated decline in patient quality of life underscores the significance of effective management. However, the lack of a fully understood pathogenesis complicates the treatment approach. Recent research has proposed the involvement of adipose fat tissue in the inflammatory response and pathogenesis of cryptoglandular anal fistula.<b>Aim:</b> The study aims to characterize the role of adipose fat tissue in the pathogenesis of cryptoglandular anal fistula, with a specific focus on understanding the potential involvement of proinflammatory cytokines in the development of chronic inflammation.<b>Materials and methods:</b> This study involved the characterization of serum levels of inflammatory cytokines and adipose tissue hormones. A total of 35 samples from both simple and complex cryptoglandular perianal fistula cases were collected during surgical procedures.<b>Results:</b> Serum levels of leptin, resistin, IL-1β, and IL-8 were significantly elevated in patients operated on due to complex cryptoglandular perianal fistula when compared to patients with simple fistula. Adiponectin was significantly lowered in samples from complex perianal fistula in comparison to simple fistula.<b>Conclusions:</b> Complex perianal cryptoglandular fistula has a reduced level of anti-inflammatory adipokines i.e. adiponectin, and an increased level of proinflammatory resistin, leptin, IL-1β, and IL-8.

Role of Adipose Tissue Hormones in Pathogenesis of Cryptoglandular Anal Fistula

The cryptoglandular perianal fistula is a common benign anorectal disorder that is managed mainly with surgery and in some cases may be an extremely challenging condition. Perianal fistulas are often characterized by significantly decreased patient quality of life. Lack of fully recognized pathogenesis of this disease makes it difficult to treat it properly. Recently, adipose tissue hormones have been proposed to play a role in the genesis of cryptoglandular anal fistulas. The expression of adipose tissue hormones and epithelial-to-mesenchymal transition (EMT) factors were characterized based on 30 samples from simple fistulas and 30 samples from complex cryptoglandular perianal fistulas harvested during surgery. Tissue levels of leptin, resistin, MMP2, and MMP9 were significantly elevated in patients who underwent operations due to complex cryptoglandular perianal fistulas compared to patients with simple fistulas. Adiponectin and E-cadherin were significantly lowered in samples from complex perianal fistulas in comparison to simple fistulas. A negative correlation between leptin and E-cadherin levels was observed. Resistin and MMP2 levels, as well as adiponectin and E-cadherin levels, were positively correlated. Complex perianal cryptoglandular fistulas have a reduced level of the anti-inflammatory adipokine adiponectin and have an increase in the levels of proinflammatory resistin and leptin. Abnormal secretion of these adipokines may affect the integrity of the EMT in the fistula tract. E-cadherin, MMP2, and MMP9 expression levels were shifted in patients with more advanced and complex perianal fistulas. Our results supporting the idea of using mesenchymal stem cells in the treatment of cryptoglandular perianal fistulas seem reasonable, but further studies are warranted.

GPR120/FFAR4: A Potential New Therapeutic Target for Inflammatory Bowel Disease

Inflammatory bowel disease, whose major forms are Crohn's disease and ulcerative colitis, is characterized by chronic inflammation of the gut due to the loss of tolerance toward antigens normally contained in the gut lumen. G protein-coupled receptor (GPR) 120 has gained considerable attention as a potential therapeutic target for metabolic disorders due to its implication in the production of the incretin hormone glucagon-like peptide 1 and the secretion of cholecystokinin. Recent studies have also highlighted the role of GPR120 in regulating immune system activity and inflammation. GPR120, expressed by intestinal epithelial cells, proinflammatory macrophages, enteroendocrine L cells, and CD4+ T cells, suppresses proinflammatory and enhances anti-inflammatory cytokine production, suggesting that GPR120 might have a pivotal role in intestinal inflammation and represent a possible therapeutic target in inflammatory bowel disease. This narrative review aims at summarizing the role of GPR120 in the maintenance of intestinal homeostasis through the analysis of the most recent studies.

Ultrasonographic and Functional Features of Symptomatic Uncomplicated Diverticular Disease

INTRODUCTION

To evaluate the ability of intestinal ultrasound (IUS) in discriminating symptomatic uncomplicated diverticular disease (SUDD) among patients with abdominal symptoms including irritable bowel syndrome (IBS).

METHODS

This observational, prospective study included consecutive patients classified into the following categories: (i) SUDD; (ii) IBS; (iii) unclassifiable abdominal symptoms; and (iv) controls, including asymptomatic healthy subjects and diverticulosis. The IUS evaluation of the sigmoid: assessed the presence of diverticula, thickness of the muscularis propria, and IUS-evoked pain, namely the intensity of pain evoked by compression with the ultrasound probe on sigmoid colon compared with an area of the left lower abdominal quadrant without underlying sigmoid colon.

RESULTS

We enrolled 40 patients with SUDD, 20 patients with IBS, 28 patients with unclassifiable abdominal symptoms, 10 healthy controls, and 20 patients with diverticulosis. Patients with SUDD displayed significantly ( P < 0.001) greater muscle thickness (2.25 ± 0.73 mm) compared with patients with IBS (1.66 ± 0.32 mm), patients with unclassifiable abdominal pain, and healthy subjects, but comparable with that of patients with diverticulosis (2.35 ± 0.71 mm). Patients with SUDD showed a greater (not significant) differential pain score than other patients. There was a significant correlation between the thickness of the muscularis propria and the differential pain score only for patients with SUDD ( r = 0.460; P : 0.01). Sigmoid diverticula were detected by colonoscopy in 40 patients (42.4%) and by IUS with a sensitivity of 96.0% and a specificity of 98.5%.

DISCUSSION

IUS could represent a useful diagnostic tool for SUDD, potentially useful in characterizing the disease and appropriately address the therapeutic approach.

GLP-1 Receptor Agonists in Obese Patients with Inflammatory Bowel Disease: from Molecular Mechanisms to Clinical Considerations and Practical Recommendations for Safe and Effective Use

PURPOSE OF REVIEW

To discuss current literature and provide practical recommendations for the safe and effective use of glucagon-like peptide 1 receptor agonists (GLP-1 RA) in people with inflammatory bowel disease (IBD) and type 2 diabetes (T2D) and/or obesity. The molecular mechanisms that justify the potential benefits of GLP-1 RA in IBD and the links between IBD, obesity, and cardiovascular disease are also discussed.

RECENT FINDINGS

Preliminary data suggest that GLP-1 RA can modulate crucial pathways in the pathogenesis of IBD, such as chronic inflammation circuits, intestinal tight junctions, and gut microbiome dysbiosis, setting the stage for human trials to investigate the role of these agents in the treatment of IBD among people with or without diabetes and obesity. However, gastrointestinal side effects related to GLP-1 RA need appropriate clinical management to mitigate risks and maximize the benefits of therapy in people with IBD. GLP-1 RA originally emerged as drugs for the treatment of hyperglycemia and are currently licensed for the management of T2D and/or overweight/obesity. However, their wealth of pleiotropic actions soon raised expectations that they might confer benefits on non-metabolic disorders. Future studies are expected to clarify whether GLP-1 RA deserve an adjunct place in the arsenal of drugs against IBD.

The Role of Intermittent Fasting in the Management of Nonalcoholic Fatty Liver Disease: A Narrative Review

Intermittent fasting is a non-pharmacological dietary approach to management of obesity and metabolic syndrome, involving periodic intervals of complete or near-complete abstinence from food and energy-containing fluids. This dietary strategy has recently gained significant popularity in mainstream culture and has been shown to induce weight loss in humans, reduce gut and systemic inflammation, and improve gut microbial diversity and dysbiosis (largely in animal models). It has been hypothesized that intermittent fasting could be beneficial in the management of nonalcoholic fatty liver disease, given the condition's association with obesity. This review summarizes protocols, potential mechanisms of action, and evidence for intermittent fasting in nonalcoholic fatty liver disease. It also highlights practical considerations for implementing intermittent fasting in clinical practice. A search of the literature for English-language articles related to intermittent fasting or time-restricted feeding and liver disease was completed in PubMed and Google Scholar. Potential mechanisms of action for effects of intermittent fasting included modulation of circadian rhythm, adipose tissue and adipokines, gut microbiome, and autophagy. Preclinical, epidemiological, and clinical trial data suggested clinical benefits of intermittent fasting on metabolic and inflammatory markers in humans. However, there was a paucity of evidence of its effects in patients with nonalcoholic fatty liver disease. More clinical studies are needed to determine mechanisms of action and to evaluate safety and efficacy of intermittent fasting in this population.

The relationship between perianal fistula activity and abdominal adipose tissue in Crohn’s disease: an observational study

Objective

The aim of this study was to analyze the relationship between abdominal adipose tissue and perianal fistula activity in patients with Crohn's disease (CD) using cross-sectional imaging.

Methods

Patients with perianal fistulizing CD who underwent pelvic magnetic resonance imaging (MRI) and abdominal computed tomography (CT) were retrospectively enrolled. We scored the fistulas in each patient's MRI images based on Van Assche's classification. The area and density of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) (at the third, fourth, and fifth lumbar (L3, L4, and L5) levels were measured by averaging five slices of measurements at each vertebral level in CT images, and areas were further standardized by the lumbar height2 (heightL1-5). The VAT/SAT ratio (VSR) and VAT/Total adipose tissue (VA/TA) index were calculated. Based on MRI scores, patients were divided into two groups with low and high activity, and their clinical, MRI features, and CT parameters were compared. We evaluated patients with follow-up MRI and compared the differences in clinical and radiological indicators among patients with different outcomes.

Results

Overall, 136 patients were included, 77 in the low-activity group and 59 in the high-activity group. Patients in the high activity group had lower subcutaneous adipose index (all levels, p < 0.05) and visceral adipose index (L3 level, p < 0.01), but higher SAT and VAT density (all levels, p < 0.01), VSR (L5 level, p = 0.07) and VA/TA index (L5 level, p < 0.05).

Conclusion

There were differences in adipose tissue composition among CD patients with different active perianal fistulas.

Fibrosis in fat: From other diseases to Crohn’s disease

Creeping fat is a specific feature of Crohn’s disease (CD) and is characterized by mesenteric fat wrapping around the intestine. It highly correlates with intestinal transmural inflammation, muscular hypertrophy, fibrosis, and stricture formation. However, the pathogenesis of creeping fat remains unclear. Molecular crosstalk exists between mesenteric fat and the intestine. Indeed, creeping fat contains different types of cells, including adipocytes and immune cells. These cell types can produce various cytokines, fatty acids, and growth factors, which affect the mesenteric fat function and modulate intestinal inflammation and immunity. Moreover, adipocyte progenitors can produce extracellular matrix to adapt to fat expansion. Previous studies have shown that fat fibrosis is an important feature of adipose tissue malfunction and exists in other diseases, including metabolic disorders, cancer, atrial fibrillation, and osteoarthritis. Furthermore, histological sections of CD showed fibrosis in the creeping fat. However, the role of fibrosis in the mesenteric fat of CD is not well understood. In this review, we summarized the possible mechanisms of fat fibrosis and its impact on other diseases. More specifically, we illustrated the role of various cells (adipocyte progenitors, macrophages, mast cells, and group 1 innate lymphoid cells) and molecules (including hypoxia-inducible factor 1-alpha, transforming growth factor-beta, platelet-derived growth factor, and peroxisome proliferator-activated receptor-gamma) in the pathogenesis of fat fibrosis in other diseases to understand the role of creeping fat fibrosis in CD pathogenesis. Future research will provide key information to decipher the role of fat fibrosis in creeping fat formation and intestinal damage, thereby helping us identify novel targets for the diagnosis and treatment of CD.

Diverticular disease in a pediatric patient with Crohn’s disease mimicking a perforated post-appendectomy appendiceal stump

We present the finding of a diverticulum in the colonic wall of the cecum, arising in the context of ileocecal stricture in a child with Crohn disease mimicking a post-appendectomy perforated appendiceal stump. To our knowledge, a non-Meckel diverticulum in a pediatric patient with Crohn disease has not yet been reported and we examine the mechanics behind it. According to the Laplace Law, the pressure inside a container with curved walls is inversely proportional to its radius. A diverticulum forms at the point of maximum stricture and at the locus of least resistance (weakness) in the bowel wall due to the inflammatory bowel disease. The long-time interval between diagnosis of ileocecal stricture and surgery (9 months) is important to allow the formation of this diverticulum. Continued follow-up in adulthood is warranted due to an increased risk of intestinal diverticular disease and neoplasms in patients with Crohn disease.

Severe Obesity Contributes to Worse Outcomes After Elective Colectomy for Chronic Diverticular Disease

BACKGROUND

Both obesity and chronic diverticular disease (DD) are on the rise. Understanding surgical outcomes for patients with obesity undergoing colectomy for DD is imperative to improve care and minimize complications. Our objective was to investigate the impact of obesity on outcomes after elective colectomy specifically for chronic DD.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program database from 2012 to 2018, patients who underwent elective colectomy for chronic DD were grouped into four body mass index categories. Baseline characteristics, surgical approach and procedure, and 30-day morbidity and mortality were assessed.

RESULTS

Of 24,559 patients, 21.7% were of normal weight, 35.8% were overweight, 35.9% were obese, and 6.6% were severely obese. Patients with severe obesity were younger, more functionally dependent, and had more comorbidities (all P [Formula: see text] 0.0001). Patients with severe obesity were more likely to have unplanned conversion to open surgery from laparoscopic and robotic approaches (AOR 2.15, 95% CI 1.24-3.70). Obesity class did not significantly affect the type of surgical procedure patients underwent (Hartmann's, colectomy with anastomosis and diversion, or colectomy with primary anastomosis). There were increased odds of any perioperative complications (AOR 1.43, 95% CI 1.19-1.71) and non-home discharge (AOR 2.39, 95% CI 1.59-3.57) in patients with severe obesity compared to normal weight patients.

CONCLUSIONS

Obesity is associated with poorer outcomes in patients undergoing elective colectomy for chronic DD. Futures studies to examine the impact of preemptive weight loss to improve outcomes after elective colectomy for chronic sequelae of DD are needed.

Magnetic resonance imaging-based body composition is associated with nutritional and inflammatory status: a longitudinal study in patients with Crohn's disease

Objective

To evaluate the changes in magnetic resonance imaging-based body composition parameters during follow-ups in patients with Crohn's disease (CD).

Methods

Between November 1, 2017, and June 30, 2021, patients diagnosed with CD, who underwent two or more magnetic resonance enterography (MRE) scans at our institution were retrospectively reviewed. The baseline and one subsequent follow-up scan for each patient were paired to form longitudinal comparisons. Skeletal muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) indexes were calculated from tissue areas measured at the third lumbar vertebra level per scan, standardized by dividing the height² and lumbar height² (height_L1–L5). We also assessed the correlation between changes in VAT to total adipose tissue ratio (VA/TA index) and CD activity scores (5-point MRE classification) using Spearman’s correlation analysis. A multivariate linear regression model was used to adjust for the follow-up duration and treatment type.

Results

Overall, 49 patients (with 49 paired scans) were enrolled. VA/TA index changes were negatively correlated with changes in skeletal muscle index (SMI; r =  − 0.339, p < 0.05). The VA/TA index (52.69 ± 10.66% vs. 49.18 ± 10.80%, p < 0.001) and the total MRE score (8.0 ± 3.9 vs. 5.7 ± 3.4, p < 0.001) decreased significantly during follow-up, regardless of follow-up duration and treatment type (both p > 0.05). Changes in total MRE score were negatively correlated with SMI changes (r =  − 0.408, p < 0.01) but positively correlated with VA/TA index changes (r = 0.479, p < 0.01).

Conclusion

An increase in SMI and a decrease in VA/TA index could reflect improved nutritional and inflammatory status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-021-01121-3.

Excessive Body Weight and Diverticular Disease

BACKGROUND

The worldwide proportion of overweight adults almost doubled from 22% in 1975 to 39% in 2016. Comparably, for the USA and Germany in 2016, the proportion was 68 and 56.8%, respectively. In Olmsted County, Minnesota, the prevalence of diverticulitis also doubled between 1980 and 2007, from 19 to 40%. Obesity substantially increases the risk of multiple gastrointestinal (GI) diseases and non-GI diseases. In a narrative review, we examined the evidence on whether obesity also increases the risk for the development of diverticulosis or diverticular disease and its outcome.

SUMMARY

Evidence suggests that being overweight (body mass index ≥25 kg/m2) or obese (≥30 kg/m2), especially viscerally obese, is a risk factor for diverticulosis, diverticular disease and diverticulitis, diverticular bleeding, more severe or complicated disease, recurrent disease, and for worse outcomes after surgery.

KEY MESSAGES

There is a well-founded association between overweight and diverticular disease as well as diverticulosis. It is not clear whether overweight per se or confounders linked with it are responsible for the association. However, means to fight the overweight and obesity epidemic might also help to reduce the prevalence of morbidity and mortality from diverticular disease.

Roles of Adipokines in Digestive Diseases: Markers of Inflammation, Metabolic Alteration and Disease Progression

Adipose tissue is a highly dynamic endocrine tissue and constitutes a central node in the interorgan crosstalk network through adipokines, which cause pleiotropic effects, including the modulation of angiogenesis, metabolism, and inflammation. Specifically, digestive cancers grow anatomically near adipose tissue. During their interaction with cancer cells, adipocytes are reprogrammed into cancer-associated adipocytes and secrete adipokines to affect tumor cells. Moreover, the liver is the central metabolic hub. Adipose tissue and the liver cooperatively regulate whole-body energy homeostasis via adipokines. Obesity, the excessive accumulation of adipose tissue due to hyperplasia and hypertrophy, is currently considered a global epidemic and is related to low-grade systemic inflammation characterized by altered adipokine regulation. Obesity-related digestive diseases, including gastroesophageal reflux disease, Barrett's esophagus, esophageal cancer, colon polyps and cancer, non-alcoholic fatty liver disease, viral hepatitis-related diseases, cholelithiasis, gallbladder cancer, cholangiocarcinoma, pancreatic cancer, and diabetes, might cause specific alterations in adipokine profiles. These patterns and associated bases potentially contribute to the identification of prognostic biomarkers and therapeutic approaches for the associated digestive diseases. This review highlights important findings about altered adipokine profiles relevant to digestive diseases, including hepatic, pancreatic, gastrointestinal, and biliary tract diseases, with a perspective on clinical implications and mechanistic explorations.

Intestinal Dysbiosis and Markers of Systemic Inflammation in Viscerally and Generally Obese Persons Living With HIV

BACKGROUND

The intestinal microbiota contributes to the pathogenesis of obesity and metabolic disorders. People living with HIV (PLWH) have a higher risk for the development of visceral adiposity with accompanying worsened cardiovascular risk.

SETTING

Convenience sample from an HIV clinic and research unit.

METHODS

To understand the relationship between adiposity and intestinal dysbiosis, we compared the gut microbiota and inflammatory markers in a cross-sectional study of viscerally obese, generally obese, and lean PLWH. Fecal intestinal microbiota was characterized by 16S ribosomal DNA sequencing. Abdominal CTs quantified subcutaneous adipose tissue and visceral adipose tissue (SAT; VAT). Serum high sensitivity C-reactive protein, adiponectin, leptin, IL-6, MCP-1, and sCD14 were assayed.

RESULTS

We studied 15, 9, and 11 participants with visceral obesity, general obesity, and lean body type, respectively. The generally obese group were all women and 2/3 African American, whereas the visceral obesity and lean groups were predominantly white and men who have sex with men. Markers of systemic inflammation and sCD14 were higher in general obesity compared with lean. sCD14 was positively correlated with VAT, but not SAT. Bacterial diversity was significantly reduced in participants with visceral and general obesity and composition of intestinal microbiota was significantly different from lean body types. Bacterial alpha diversity was negatively correlated with VAT area, waist/hip ratio, and sCD14, but not with SAT area.

CONCLUSIONS

In this exploratory study, obesity in general was associated with dysbiotic intestinal microbiota. The relationships of VAT to bacterial diversity and sCD14 suggest that dysbiosis in viscerally obese PLWH could be associated with heightened inflammatory state.

Multiple Small Bowel Diverticula Were an Unexpected Finding During Laparoscopic Enterectomy for Crohn's Disease

Introduction:

Small bowel diverticulosis (SBD) is a rare entity. Although it is usually an asymptomatic condition, clinical manifestations may vary from non-specific clinical signs to severe and complicated disease. The coexistence of SBD and Crohn’s disease (CD) is rarely reported in the current literature.

Aim:

We present a rare case of concomitant Crohn’s disease (CD) and SBD in a male patient, where multiple jejunal diverticula were an incidental intraoperative finding. Preoperative evaluation with magnetic resonance enterography (MRE) failed to recognize the coexistence of these two entities. Surgeons should be aware of the possibility of this rare situation.

Case report:

A 52-year-old Caucasian male diagnosed with CD was referred to our department for surgical intervention due to an ileal stricture. The patient reported no past medical history, except for a few episodes of bloody diarrhoea during a three-year period. The index colonoscopy revealed luminal narrowing in the ileum at approximately 70 cm proximal to the ileocaecal valve, and biopsies revealed findings compatible with CD. Clinical examination and laboratory tests were unremarkable one day before surgery. The patient underwent laparoscopic segmental resection of the affected part of the ileum. Intraoperatively, multiple non-inflamed diverticula along the jejunum extending from the Treitz ligament to the proximal ileum were recognized. Our patient had an uncomplicated post-operative course and was discharged on the fifth post-operative day. Pathological examination revealed features compatible with CD in the active phase. The patient was referred to his gastroenterological team for further consultation regarding the appropriate post-operative management.

Conclusion:

Concomitant CD and SBD is a rare condition, and the differential diagnosis may be challenging due to overlapping symptoms.

Epigenetics, DNA Organization, and Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders affecting the gastrointestinal tract. The incidence of IBD is increasing, with more cases occurring in developed countries. Multiple factors such as genetics, environmental changes, gut microbiota, and immune abnormalities have been associated with development of IBD. In recent years, it has become increasingly apparent that epigenetic modifications of chromatin and the manner in which chromatin is organized in the nucleus are additionally important elements that can influence responses induced by the factors described above, and may therefore contribute to the onset and pathogenesis of IBD. Epigenetics and chromatin organization regulate diverse functions that include maintenance of homeostasis in the intestinal epithelium, the development and differentiation of immune cells, and modulation of responses generated by the immune system to defend against potential pathogens. Furthermore, changes in epigenetic chromatin marks and in chromatin organization have now been linked to differential gene expression in IBD patient cells. Although direct evidence for a role of histone modifications in IBD is currently very limited, in this review, we summarize the links between various epigenetic modifications, the proteins that catalyze or recognize these modifications, and the development or progression of IBD in human and experimental IBD. We also discuss how epigenetics influence the organization of DNA contacts to regulate gene expression and the implications this may have for diagnosing and treating IBD.

The Mesentery, Systemic Inflammation, and Crohn's Disease

Initially thought to be a structure that only provided support to the abdominal contents, the mesentery has now gained special attention in the scientific community. The new approach of studying the mesentery as an individual organ has highlighted its importance in the development of local and systemic inflammatory diseases and its potential role in Crohn's disease. Its topographical relationship with the intestine in the setting of active inflammation and "creeping fat" is possibly one of the most important arguments for including the mesentery as an important factor in the pathogenesis of Crohn's disease. In this review, we discuss the importance of the mesentery from the anatomical and embryological standpoints. We also will summarize data on mesenteric inflammation in patients with Crohn's disease. The significance of the mesentery in systemic inflammatory syndromes will be discussed, and we provide an overview of primary inflammatory disorders of the mesentery. Finally, we discuss surgical approaches for patients requiring resection for Crohn's disease that incorporate mesenteric factors, pointing out recent data suggesting that these have the potential for improving outcomes and reducing disease recurrence. 10.1093/ibd/izy201_video1izy201.video15794169491001.

Preventive Effect of Spontaneous Physical Activity on the Gut-Adipose Tissue in a Mouse Model That Mimics Crohn's Disease Susceptibility

Crohn’s disease is characterized by abnormal ileal colonization by adherent-invasive E. coli (AIEC) and expansion of mesenteric adipose tissue. This study assessed the preventive effect of spontaneous physical activity (PA) on the gut-adipose tissue in a mouse model that mimics Crohn’s disease susceptibility. Thirty-five CEABAC10 male mice performed spontaneous PA (wheel group; n = 24) or not (controls; n = 11) for 12 weeks. At week 12, mice were orally challenged with the AIEC LF82 strain for 6 days. Body composition, glycaemic control, intestinal permeability, gut microbiota composition, and fecal short-chain fatty acids were assessed in both groups. Animals were fed a high fat/high sugar diet throughout the study. After exposure to AIEC, mesenteric adipose tissue weight was lower in the wheel group. Tight junction proteins expression increased with spontaneous PA, whereas systemic lipopolysaccharides were negatively correlated with the covered distance. Bifidobacterium and Lactobacillus decreased in controls, whereas Oscillospira and Ruminococcus increased in the wheel group. Fecal propionate and butyrate were also higher in the wheel group. In conclusion, spontaneous physical activity promotes healthy gut microbiota composition changes and increases short-chain fatty acids in CEABAC10 mice fed a Western diet and exposed to AIEC to mimic Crohn’s disease.

Lifestyle Factors in Late Adolescence Associate With Later Development of Diverticular Disease Requiring Hospitalization

BACKGROUND & AIMS

The burden of diverticular disease on society is high and is increasing with an aging population. It is therefore important to identify risk factors for disease development or progression. Many lifestyle behaviors during adolescence affect risk for later disease. We searched for adolescent lifestyle factors that affect risk of diverticular disease later in life.

METHODS

We performed a retrospective analysis of data from 43,772 men (age, 18-20 y) conscripted to military service in Sweden from 1969 through 1970, with a follow-up period of 39 years. All conscripts underwent an extensive mental and physical health examination and completed questionnaires covering alcohol consumption, smoking, and use of recreational drugs; cardiovascular fitness was assessed using an ergometer cycle at the time of conscription. Outcome data were collected from national registers to identify discharge diagnoses of diverticular disease until the end of 2009. We performed Cox regression analysis to determine whether body mass index, cardiovascular fitness, smoking, use of recreational drugs, alcohol consumption, and risky use of alcohol, at time of conscription are independent risk factors for development of diverticular disease.

RESULTS

Overweight and obese men had a 2-fold increased risk of diverticular disease compared to normal-weight men (hazard ratio, 2.00; P < .001). A high level of cardiovascular fitness was associated with a reduced risk of diverticular disease requiring hospitalization (P = .009). Smoking (P = .003), but not use of recreational drugs (P = .11), was associated with an increased risk of diverticular disease requiring hospitalization. Risky use of alcohol, but not alcohol consumption per se, was associated with a 43% increase in risk of diverticular disease requiring hospitalization (P = .007).

CONCLUSIONS

In a retrospective analysis of data from 43,772 men in Sweden, we associated being overweight or obese, a smoker, a high-risk user of alcohol, and/or having a low level of cardiovascular fitness in late adolescence with an increased risk of developing diverticular disease requiring hospitalization later in life. Improving lifestyle factors among adolescents might reduce the economic burden of diverticular disease decades later.

Visceral fat area, not body mass index, predicts postoperative 30-day morbidity in patients undergoing colon resection for cancer

PURPOSE

Colectomy for cancer in obese patients is technically challenging and may be associated with worse outcomes. Whether visceral obesity, as measured on computed tomography, is a better predictor of complication than body mass index (BMI) or determines long-term oncologic outcomes has not been well characterized. This study examines the association between derived anthropometrics and postoperative complication and long-term oncologic outcomes.

METHODS

Retrospective review of patients undergoing elective colectomy for cancer at a single tertiary-care center from 2010 to 2016. Adipose tissue distribution measurements, including visceral fat area (VFA), were determined from preoperative imaging. The primary outcome was 30-day postoperative complication; secondary outcomes included overall and disease-free survival. Multivariable logistic regression was performed to determine association between obesity metrics and outcome.

RESULTS

Two hundred and sixty-four patients underwent 266 primary resections of colon cancer. Twenty-eight patients (10.5%) developed major morbidity (Clavien-Dindo grade ≥ III). VFA but not BMI was significantly associated with morbidity in multivariate analysis (p = 0.004, odds ratio 1.99, 95% confidence interval 1.25-3.19). No other imaging-derived anthropometric was associated with increased morbidity. In receiver operating characteristic analysis, VFA was predictive of major morbidity (area under curve 0.660). A cutoff value of VFA ≥ 191 cm² was associated with 50% sensitivity and 76% specificity for predicting major morbidity. Patients with VFA ≥ 191cm² had 19.4% risk of morbidity, whereas those with < 191 cm² had 7.2% risk (relative risk ratio 2.69, unadjusted p = 0.004). Neither VFA nor BMI was associated with overall or disease-free survival.

CONCLUSION

VFA but not BMI predicts morbidity following elective surgery for colon cancer.

Inflammation management in acute diverticulitis: current perspectives

The pathogenesis of diverticular disease and acute diverticulitis is still unclear and many different hypotheses have been formulated. Seemingly, there are several related factors such as chronic inflammation, gut microbiome, obesity and the immunogenic properties of fat tissue and diet. Inflammation plays a pivotal role in diverticular disease and acute diverticulitis. The aim of the present review is to investigate the role of inflammation in diverticular disease as well as in mild and complicated acute diverticulitis with a focus on current research and treatment perspectives.

Patients with inflammatory bowel disease have higher abdominal adiposity and less skeletal mass than healthy controls

Background

Abdominal fat type and distribution have been associated with complicated Crohn’s disease and adverse postoperative outcomes. Few studies have assessed the abdominal distribution of fat and lean stores in patients with inflammatory bowel disease (IBD) and compared this with healthy controls. This retrospective study aimed to compare the abdominal body composition in IBD patients who failed medical treatment and who underwent computed tomography (CT) imaging prior to gastrointestinal surgery with healthy controls. Associations between preoperative abdominal body composition and postoperative outcomes within a year of surgery were explored.

Methods

Abdominal body composition was evaluated in 22 presurgical patients with medically refractory IBD (18 with Crohn’s disease) and 22 healthy controls, using routinely acquired CT. Total fat, subcutaneous fat, visceral fat, and skeletal muscle cross-sectional area were measured.

Results

An independent disease effect was observed, explaining a fat deposition excess of 38 cm² and a skeletal muscle deficit of 15 cm² in IBD. Abdominal skeletal muscle correlated with visceral fat for the control (rho=0.51, P=0.015), but not for the IBD group (rho=-0.13, P=0.553). A positive correlation observed between subcutaneous fat with skeletal muscle in the controls (rho=0.47, P=0.026) was inverted in the IBD group (rho=-0.43, P=0.045). Preoperative abdominal body composition was not predictive of postoperative outcomes.

Conclusions

A higher degree of abdominal adiposity, a lower skeletal mass and a larger body size for the same anthropometry can be expected in IBD patients. Preoperative abdominal body composition is not associated with surgical outcomes.

Anatomical, Physiological, and Functional Diversity of Adipose Tissue

Adipose tissue depots can exist in close association with other organs, where they assume diverse, often non-traditional functions. In stem cell-rich skin, bone marrow, and mammary glands, adipocytes signal to and modulate organ regeneration and remodeling. Skin adipocytes and their progenitors signal to hair follicles, promoting epithelial stem cell quiescence and activation, respectively. Hair follicles signal back to adipocyte progenitors, inducing their expansion and regeneration, as in skin scars. In mammary glands and heart, adipocytes supply lipids to neighboring cells for nutritional and metabolic functions, respectively. Adipose depots adjacent to skeletal structures function to absorb mechanical shock. Adipose tissue near the surface of skin and intestine senses and responds to bacterial invasion, contributing to the body's innate immune barrier. As the recognition of diverse adipose depot functions increases, novel therapeutic approaches centered on tissue-specific adipocytes are likely to emerge for a range of cancers and regenerative, infectious, and autoimmune disorders.

Unexpected Fat Distribution in Adolescents With Narcolepsy

Narcolepsy type 1 is a chronic sleep disorder with significantly higher BMI reported in more than 50% of adolescent patients, putting them at a higher risk for metabolic syndrome in adulthood. Although well-documented, the body fat distribution and mechanisms behind weight gain in narcolepsy are still not fully understood but may be related to the loss of orexin associated with the disease. Orexin has been linked to the regulation of brown adipose tissue (BAT), a metabolically active fat involved in energy homeostasis. Previous studies have used BMI and waist circumference to characterize adipose tissue increases in narcolepsy but none have investigated its specific distribution. Here, we examine adipose tissue distribution in 19 adolescent patients with narcolepsy type 1 and compare them to 17 of their healthy peers using full body magnetic resonance imaging (MRI). In line with previous findings we saw that the narcolepsy patients had more overall fat than the healthy controls, but contrary to our expectations there were no group differences in supraclavicular BAT, suggesting that orexin may have no effect at all on BAT, at least under thermoneutral conditions. Also, in line with previous reports, we observed that patients had more total abdominal adipose tissue (TAAT), however, we found that they had a lower ratio between visceral adipose tissue (VAT) and TAAT indicating a relative increase of subcutaneous abdominal adipose tissue (ASAT). This relationship between VAT and ASAT has been associated with a lower risk for metabolic disease. We conclude that while weight gain in adolescents with narcolepsy matches that of central obesity, the lower VAT ratio may suggest a lower risk of developing metabolic disease.

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.