Abnormalities of neuromuscular anatomy in diverticular disease

Different Clinical Characteristics of Right-Sided Versus Left-Sided Colonic Diverticular Complications: A Four-Year Retrospective Study in a Chinese Population

Aim: To determine whether right-sided and left-sided colonic diverticular complications have different clinical manifestations and treatment outcomes. Methods: Patients diagnosed with diverticulitis or diverticular hemorrhage from January 2019 to December 2023 were retrieved. Patients were assigned into the right-sided group and the left-sided group according to the colon affected by diverticular complications. For each patient, age, gender, body mass index (BMI), lifestyle, clinical presentation, and concomitant medication were recorded. Clinical characteristics and treatment outcomes were compared with between the two groups. Results: A total of 123 patients were included in this study, 89 in the right-sided group and 34 in the left-sided group. Patients in the right-sided group presented a significantly lower mean age (43.33 vs. 66.35 yrs old, p < 0.0001) and a smaller proportion of patients with BMI above 25 (10.11% vs. 24.76%, p = 0.02). Left-sided group diverticulitis had a significantly higher proportion of Hinchey III to IV (29.41% vs. 1.12%, p = 0.0001) and rate of intensified conservative treatment (30.77% vs. 2.38%, p = 0.0003). Patients in the left-sided group had a higher rate of crowding of diverticula (diverticular number counted >20) (35.29% vs. 1.12%, p < 0.01). Two patients in the right-sided group and eight in the left received laparotomy because of diverticulitis. All three cases of hemorrhage were in the right-sided group. Conclusion: Compared with the left, right-sided diverticulosis is characterized by a younger age, less-virulent diverticulitis, and potentially higher hemorrhagic propensity. Different mechanisms between the groups may exist to mediate the onset and development of diverticulosis and its complications.

Impaired Expression of Neuregulin 1 and Nicotinic Acetylcholine Receptor β4 Subunit in Diverticular Disease

Neuregulin 1 (NRG1) regulates the expression of the nicotinic acetylcholine receptor (nAChR) and is suggested to promote the survival and maintenance of the enteric nervous system (ENS), since deficiency of its corresponding receptor complex ErbB2/ErbB3 leads to postnatal colonic aganglionosis. As diverticular disease (DD) is associated with intestinal hypoganglionosis, the NRG1-ErbB2/ErbB3 system and the nAChR were studied in patients with DD and controls. Samples of tunica muscularis of the sigmoid colon from patients with DD (n = 8) and controls (n = 11) were assessed for mRNA expression of NRG1, ErbB2, and ErbB3 and the nAChR subunits α3, α5, α7, β2, and β4. Site-specific gene expression levels of the NRG1-ErbB2/3 system were determined in myenteric ganglia harvested by laser microdissection (LMD). Localization studies were performed by immunohistochemistry for the NRG1-ErbB2/3 system and nAChR subunit β4. Rat enteric nerve cell cultures were stimulated with NRG1 or glial-cell line derived neurotrophic factor (GDNF) for 6 days and mRNA expression of the aforementioned nAchR was measured. NRG1, ErbB3, and nAChR subunit β4 expression was significantly down-regulated in both the tunica muscularis and myenteric ganglia of patients with DD compared to controls, whereas mRNA expression of ErbB3 and nAChR subunits β2, α3, α5, and α7 remained unaltered. NRG1, ErbB3, and nAChR subunit β4 immunoreactive signals were reduced in neuronal somata and the neuropil of myenteric ganglia from patients with DD compared to control. nAChR subunit β4 exhibited also weaker immunoreactive signals in the tunica muscularis of patients with DD. NRG1 treatment but not GDNF treatment of enteric nerve cell cultures significantly enhanced mRNA expression of nAchR β4. The down-regulation of NRG1 and ErbB3 in myenteric ganglia of patients with DD supports the hypothesis that intestinal hypoganglionosis observed in DD may be attributed to a lack of neurotrophic factors. Regulation of nAChR subunit β4 by NRG1 and decreased nAChR β4 in patients with DD provide evidence that a lack of NRG1 may affect the composition of enteric neurotransmitter receptor subunits thus contributing to the intestinal motility disorders previously reported in DD.

Diverticular Disease in the Elderly

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Ultrastructural changes of the human enteric nervous system and interstitial cells of Cajal in diverticular disease

BACKGROUND

In spite of numerous advances in understanding diverticular disease, its pathogenesis remains one of the main problems to be solved. We aimed to investigate the ultrastructural changes of the enteric nervous system in unaffected individuals, in asymptomatic patients with diverticulosis and in patients with diverticular disease.

METHODS

Transmission electron microscopy was used to analyse samples of the myenteric, outer submucosal and inner submucosal plexuses from patients without diverticula (n=9), asymptomatic patients with diverticulosis (n=7) and in patients with complicated diverticular disease (n=9). We described the structure of ganglia, interstitial cells of Cajal and enteric nerves, as well as their relationship with each other. The distribution and size of nerve processes were analysed quantitatively.

RESULTS

In complicated diverticular disease, neurons exhibited larger lipofuscin-like inclusions, their membranous organelles had larger cisterns and the nucleus showed deeper indentations. Nerve remodeling occurred in every plexus, characterised by an increased percentage of swollen and fine neurites. Interstitial cells of Cajal had looser contacts with the surrounding cells and showed cytoplasmic depletion and proliferation of the rough endoplasmic reticulum. In asymptomatic patients with diverticulosis, alterations of enteric nerves and ICC were less pronounced.

CONCLUSIONS

In conclusion, the present findings suggest that most ultrastructural changes of the enteric nervous system occur in complicated diverticular disease. The changes are compatible with damage to the enteric nervous system and reactive remodeling of enteric ganglia, nerves and interstitial cells of Cajal. Disrupted architecture of enteric plexuses might explain clinical and pathophysiological changes associated with diverticular disease.

Genome-wide association analysis of diverticular disease points towards neuromuscular, connective tissue and epithelial pathomechanisms

OBJECTIVE

Diverticular disease is a common complex disorder characterised by mucosal outpouchings of the colonic wall that manifests through complications such as diverticulitis, perforation and bleeding. We report the to date largest genome-wide association study (GWAS) to identify genetic risk factors for diverticular disease.

DESIGN

Discovery GWAS analysis was performed on UK Biobank imputed genotypes using 31 964 cases and 419 135 controls of European descent. Associations were replicated in a European sample of 3893 cases and 2829 diverticula-free controls and evaluated for risk contribution to diverticulitis and uncomplicated diverticulosis. Transcripts at top 20 replicating loci were analysed by real-time quatitative PCR in preparations of the mucosal, submucosal and muscular layer of colon. The localisation of expressed protein at selected loci was investigated by immunohistochemistry.

RESULTS

We discovered 48 risk loci, of which 12 are novel, with genome-wide significance and consistent OR in the replication sample. Nominal replication (p<0.05) was observed for 27 loci, and additional 8 in meta-analysis with a population-based cohort. The most significant novel risk variant rs9960286 is located near CTAGE1 with a p value of 2.3×10^-10 and 0.002 (OR_allelic=1.14 (95% CI 1.05 to 1.24)) in the replication analysis. Four loci showed stronger effects for diverticulitis, PHGR1 (OR 1.32, 95% CI 1.12 to 1.56), FAM155A-2 (OR 1.21, 95% CI 1.04 to 1.42), CALCB (OR 1.17, 95% CI 1.03 to 1.33) and S100A10 (OR 1.17, 95% CI 1.03 to 1.33).

CONCLUSION

In silico analyses point to diverticulosis primarily as a disorder of intestinal neuromuscular function and of impaired connective fibre support, while an additional diverticulitis risk might be conferred by epithelial dysfunction.

Diverticulosis, Symptoms and Colonic Inflammation: A Population-Based Colonoscopy Study

INTRODUCTION

Low-grade chronic inflammation has been suggested to play a role in uncomplicated asymptomatic and symptomatic diverticular disease. However, population-based studies are lacking. We investigated whether community participants with diverticulosis, with or without symptoms, would have colonic inflammation on histology and serology.

METHODS

In a nested case-control study of 254 participants from the population-based colonoscopy (PopCol) study, colonic histological inflammatory markers and serological C-reactive protein levels were analyzed in cases with diverticulosis and controls without diverticulosis. Statistical methods included logistic and linear regression models.

RESULTS

Background variables including age (P = 0.92), sex (P = 1.00), body mass index (P = 0.71), smoking (P = 0.34), and recent antibiotic exposure (P = 0.68) were similar between cases and controls. Cases reported more abdominal pain (P = 0.04) and diarrhea symptoms (mushy and high-frequency stools) than controls (P = 0.01 and P = 0.03, respectively) but were otherwise similar. The median C-reactive protein levels were similar among cases and controls [1.05 mg/L (0.3, 2.7) vs 0.8 (0.4, 2.2), P = 0.53]. There was a trend of increased numbers of cecal lymphoid aggregates in cases vs controls (P = 0.07), but no other associations between diverticulosis and inflammatory markers on histology were found. Similarly, no serological or mucosal inflammation was associated with symptomatic cases of diarrhea or abdominal pain vs asymptomatic controls.

CONCLUSIONS

In a general community sample, both asymptomatic and symptomatic diverticulosis are not associated with colonic mucosal inflammation. Other explanations for symptomatic colonic diverticulosis need to be identified.

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.

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.

No neuronal loss, but alterations of the GDNF system in asymptomatic diverticulosis

Background

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor known to promote the survival and maintenance of neurons not only in the developing but also in the adult enteric nervous system. As diverticular disease (DD) is associated with reduced myenteric neurons, alterations of the GDNF system were studied in asymptomatic diverticulosis (diverticulosis) and DD.

Methods

Morphometric analysis for quantifying myenteric ganglia and neurons were assessed in colonic full-thickness sections of patients with diverticulosis and controls. Samples of tunica muscularis (TM) and laser-microdissected myenteric ganglia from patients with diverticulosis, DD and controls were analyzed for mRNA expression levels of GDNF, GFRA1, and RET by RT-qPCR. Myenteric protein expression of both receptors was quantified by fluorescence-immunohistochemistry of patients with diverticulosis, DD, and controls.

Results

Although no myenteric morphometric alterations were found in patients with diverticulosis, GDNF, GFRA1 and RET mRNA expression was down-regulated in the TM of patients with diverticulosis as well as DD. Furthermore GFRA1 and RET myenteric plexus mRNA expression of patients with diverticulosis and DD was down-regulated, whereas GDNF remained unaltered. Myenteric immunoreactivity of the receptors GFRα1 and RET was decreased in both asymptomatic diverticulosis and DD patients.

Conclusion

Our data provide evidence for an impaired GDNF system at gene and protein level not only in DD but also during early stages of diverticula formation. Thus, the results strengthen the idea of a disturbed GDNF-responsiveness as contributive factor for a primary enteric neuropathy involved in the pathogenesis and disturbed intestinal motility observed in DD.

Symptomatic Diverticulosis Is Characterized By Loose Stools

BACKGROUND & AIMS

Symptomatic uncomplicated diverticular disease is considered to be a discreet clinical entity distinct from irritable bowel syndrome (IBS), but population-based data are unavailable. We aimed to investigate the prevalence and location of diverticulosis in the general population, and its association with colonic symptoms and mental health. We propose that individuals with diverticulosis would report more constipation and IBS.

METHODS

We performed a population-based study of randomly selected adults born in Sweden (age, 18-70 y; 57.2% women); 745 received a gastroenterology consultation, completed validated abdominal symptom and mental health questionnaires, and were examined by colonoscopy. Logistic regression was used to calculate the associations between diverticulosis and age, sex, gastrointestinal symptoms, anxiety, depression, and self-rated health.

RESULTS

Among the 742 participants (54.6% women), 130 (17.5%) had diverticulosis. Age was the strongest predictor of diverticulosis (P < .001), and diverticulosis was rare in participants younger than 40 years (0.7%). All participants with diverticulosis had sigmoid involvement. Participants with diverticulosis were more likely to report loose stools (odds ratio [OR], 1.88; 95% confidence interval [CI], 1.20-2.96), urgency (OR, 1.64; 95% CI, 1.02-2.63), passing mucus (OR, 2.26; 95% CI, 1.08-4.72), and a high stool frequency (OR, 2.02; 95% CI, 1.11-3.65). Diverticulosis was associated with abdominal pain (OR, 2.10; 95% CI, 1.01-4.36; P = .047) and diarrhea-predominant IBS (OR, 9.55; 95% CI, 1.08-84.08; P = .04) in participants older than 60 years. The presence of anxiety and depression and self-rated health were similar in participants with and without diverticulosis.

CONCLUSIONS

The prevalence of diverticulosis is age-dependent. Diverticulosis is associated with diarrhea in subjects across all age ranges. In subjects older than age 60, diverticulosis is associated with abdominal pain and diarrhea-predominant IBS.

Role of cyclooxygenase isoforms in the altered excitatory motor pathways of human colon with diverticular disease

BACKGROUND AND PURPOSE

The COX isoforms (COX-1, COX-2) regulate human gut motility, although their role under pathological conditions remains unclear. This study examines the effects of COX inhibitors on excitatory motility in colonic tissue from patients with diverticular disease (DD).

EXPERIMENTAL APPROACH

Longitudinal muscle preparations, from patients with DD or uncomplicated cancer (controls), were set up in organ baths and connected to isotonic transducers. Indomethacin (COX-1/COX-2 inhibitor), SC-560 (COX-1 inhibitor) or DFU (COX-2 inhibitor) were assayed on electrically evoked, neurogenic, cholinergic and tachykininergic contractions, or carbachol- and substance P (SP)-induced myogenic contractions. Distribution and expression of COX isoforms in the neuromuscular compartment were assessed by RT-PCR, Western blot and immunohistochemical analysis.

KEY RESULTS

In control preparations, neurogenic cholinergic contractions were enhanced by COX inhibitors, whereas tachykininergic responses were blunted. Carbachol-evoked contractions were increased by indomethacin or SC-560, but not DFU, whereas all inhibitors reduced SP-induced motor responses. In preparations from DD patients, COX inhibitors did not affect electrically evoked cholinergic contractions. Both indomethacin and DFU, but not SC-560, decreased tachykininergic responses. COX inhibitors did not modify carbachol-evoked motor responses, whereas they counteracted SP-induced contractions. COX-1 expression was decreased in myenteric neurons, whereas COX-2 was enhanced in glial cells and smooth muscle.

CONCLUSIONS AND IMPLICATIONS

In control colon, COX-1 and COX-2 down-regulate cholinergic motility, whereas both isoforms enhance tachykininergic motor activity. In the presence of DD, there is a loss of modulation by both COX isoforms on the cholinergic system, whereas COX-2 displays an enhanced facilitatory control on tachykininergic contractile activity.

[Treatment of the acute diverticulitis: A systematic review]

Acute diverticulitis is a common disease with increasing incidence. In most of cases, diagnosis is made at an uncomplicated stage offering a curative attempt under medical treatment and use of antibiotics. There is a risk of diverticulitis recurrence. Uncomplicated diverticulitis is opposed to complicated forms (perforation, abscess or fistula). Recent insights in the pathophysiology of diverticulitis, the natural history, and treatments have permitted to identify new treatment strategies. For example, the use of antibiotics tends to decrease; surgery is now less invasive, percutaneous drainage is preferred, peritoneal lavage is encouraged. Treatments of the diverticulitis are constantly evolving. In this review, we remind the pathophysiology and natural history, and summarize new recommendations for the medical and surgical treatment of acute diverticulitis.

Left colon acute diverticulitis: an update on diagnosis, treatment and prevention

Diverticulosis of the colon is a common disease with an increasing incidence in Western Countries. It represents a significant burden for National Health Systems in terms of costs. Most people with diverticulosis remain asymptomatic, about one quarter of them will develop an episode of symptomatic diverticular disease and up to 5% an episode of acute diverticulitis (AD). AD shows an increasing prevalence. Recently, progresses have been reached about the etiology, pathogenesis, natural course of diverticular disease and its complications; improvements about the diagnosis and treatment of AD have been achieved. However, the treatment options are not well defined because of a lack of solid evidence: there are few systematic reviews and well conducted trials to guide decision-making in the treatment of AD and in the prevention of its recurrences. This review describes the recent evidence about diagnosis, treatment and prevention of AD.

Colonic wall changes in patients with diverticular disease - is there a predisposition for a complicated course?

BACKGROUND

The aim of this study was to evaluate colonic wall changes and enteric neuropathy in patients with either uncomplicated (UDD) or complicated diverticular disease (CDD). Furthermore, we evaluated the presence of an anatomic sphincter at the rectosigmoid junction (RSJ).

METHODS

Samples of colonic tissue from fifteen patients with UDD, fifteen patients with CDD and fifteen patients as control were collected. Collagen quotient I/III was measured with the Sirius-red test, expression of MMP-1, MMP-13, innervation (S100), proliferation (Ki67) and apoptosis (TUNEL) in the colonic wall were investigated by immunohistochemical studies. Furthermore, measurements of the different layers were performed to investigate the RSJ.

RESULTS

Patients with either UDD or CDD had lower collagen I/III quotients compared to the control group, significant for CDD (p = 0.007). For MMP-1 and MMP-13 only a slight increase for patients with CDD was found. The percentage of proliferating (Ki67) and apoptotic (TUNEL) cells was significantly higher for patients with CDD than in the control group (p = 0.016; p = 0.037). Upon investigating the S100-expression a significant reduce in glial cells density was found in the myenteric and mucosal plexus for both groups (UDD and CDD) compared to the control group. Measurements of the different colon layers oral, aboral and at the RSJ revealed equal values.

CONCLUSIONS

This study has shown that colonic wall changes and enteric neuropathy seem to play a role in the pathogenesis of colonic diverticulosis. None of our results suggest a predisposition for a complicated diverticular disease. Furthermore, the presence of an anatomic sphincter at the rectosigmoid junction could not be detected.

The GDNF System Is Altered in Diverticular Disease - Implications for Pathogenesis

Background & Aims

Absence of glial cell line-derived neurotrophic factor (GDNF) leads to intestinal aganglionosis. We recently demonstrated that patients with diverticular disease (DD) exhibit hypoganglionosis suggesting neurotrophic factor deprivation. Thus, we screened mRNA expression pattern of the GDNF system in DD and examined the effects of GDNF on cultured enteric neurons.

Methods

Colonic specimens obtained from patients with DD (n = 21) and controls (n = 20) were assessed for mRNA expression levels of the GDNF system (GDNF, GDNF receptors GFRα1 and RET). To identify the tissue source of GDNF and its receptors, laser-microdissected (LMD) samples of human myenteric ganglia and intestinal muscle layers were analyzed separately by qPCR. Furthermore, the effects of GDNF treatment on cultured enteric neurons (receptor expression, neuronal differentiation and plasticity) were monitored.

Results

mRNA expression of GDNF and its receptors was significantly down-regulated in the muscularis propria of patients with DD. LMD samples revealed high expression of GDNF in circular and longitudinal muscle layers, whereas GDNF receptors were also expressed in myenteric ganglia. GDNF treatment of cultured enteric neurons increased mRNA expression of its receptors and promoted neuronal differentiation and plasticity revealed by synaptophysin mRNA and protein expression.

Conclusions

Our results suggest that the GDNF system is compromised in DD. In vitro studies demonstrate that GDNF enhances expression of its receptors and promotes enteric neuronal differentiation and plasticity. Since patients with DD exhibit hypoganglionosis, we propose that the observed enteric neuronal loss in DD may be due to lacking neurotrophic support mediated by the GDNF system.