The enteric serotonergic system is altered in patients with diverticular disease

Neutrophil- and Platelet-Lymphocyte Ratio as Biomarkers of Severity in Complicated Diverticular Disease

INTRODUCTION

Diverticulitis is a prevalent gastrointestinal disease that may require surgical intervention. The aim of the study was to investigate the involvement of neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) as biomarkers of severity in complicated diverticular disease (CDD) in Mexican patients and their correlation with the need for surgical intervention, the length of hospital stay, and mortality.

MATERIAL AND METHODS

An observational, longitudinal, and retrospective study performed from 2017 to 2021 was considered in patients over 18 years of age, with a diagnosis of CDD by using computed tomography and with a hemogram taken in the first 24 hours upon admission to the emergency department to describe the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of NLR and PLR in the CDD.  Results: A total of 102 Mexican patients suffering from CDD, 54% women and 46% men with a mean of 59 years, were analyzed. According to Hinchey's classification, 79 (77.5%) patients showed type I, 12 (12.8%) type II, 5 (4.9%) type III, and 6 (5.9%) type IV. The mean hospital stay was 8.8 days, with a mortality rate of 3.9%. The cut-off value was established at 5.1 for NLR according to the results of the receiver operating characteristic (ROC) curve with an area under the curve (AUC) of 0.633, a sensitivity of 90%, a specificity of 43%, PPV of 21.8%, and NPV of 96% for the prediction of CDD. A cut-off value for PLR at 72 was established according to the results of the ROC curve with an AUC of 0.482, a sensitivity of 78%, a specificity of 40%, PPV of 96%, and NPV of 9% for the prediction of CDD.

CONCLUSION

The NLR and PLR are easily calculable and accessible biomarkers that can be part of the decision-making for the diagnosis and treatment of CDD in Mexican people as has been observed in other populations. However, more prospective, multicenter comparative studies are needed to assess the efficacy and safety of these biomarkers in relation to those already described.

Serotonin Metabolism and Serotonin Receptors Expression Are Altered in Colon Diverticulosis

Background and Objectives: Diverticulosis is frequently accompanied by altered bowel habits. The biogenic amines within colonic mucosa control bowel motility, and in particular, alterations in serotonin signaling may play a role in colon diverticulosis. The aim of the study was to assess the concentration of biogenic amines and serotonin receptor expression in the colonic mucosa in patients with diverticulosis and healthy controls. Materials and Methods: This prospective, comparative study included 59 individuals: 35 with sigmoid diverticulosis and 24 healthy controls. The study was held at the Department of Gastroenterology and Internal Medicine, Medical University of Warsaw, Poland. Mucosal samples were taken from the right and left colon during a colonoscopy in all patients. Concentrations of norepinephrine, 3-methoxy-4-hydroxyphenylglycol, dopamine, homovanillic acid, serotonin, and 5-hydroxyindoleacetic acid were measured with high-performance liquid chromatography. Expressions of human 5-hydroxytryptamine receptor 3A, 5-hydroxytryptamine receptor 4, 5-hydroxytryptamine receptor 7, solute carrier family 6 member 4 (SERT) for serotonin, as well as the neuroglia activation markers glial fibrillary acidic protein, S100 calcium-binding protein B, and proteolipid protein 1, were assessed with polymerase chain reaction. Results: The median age and sex distribution were comparable in both study groups (median 69 y vs. 52 y; p < 0.455 and males/females in cases 11/17 vs. 18/19 in controls; p < 0.309). In diverticulosis patients, there was a higher concentration of serotonin in the left affected colon compared to the right healthy part of the colon (median 8239 pg/mg vs. 6326 pg/mL; p < 0.01). The SERT expression was lower in the affected left segment compared to the right colon (median 0.88 vs. 1.36; p < 0.01). There was a higher colonic mucosa concentration of serotonin (median 8239 pg/mg vs. 6000 pg/mL; p < 0.02) and 5-hydroxyindoleacetic acid/serotonin ratio (median 0.27 vs. 0.47; p < 0.01) in diverticulosis patients compared to controls in the left side of the colon. Conclusions: The concentration of serotonin in the mucosa of the colon segment affected by diverticula is higher than in the healthy segment in the same individuals and higher than in healthy controls. These results underline serotonin signaling in colon diverticulosis pathophysiology.

Colonic diverticular disease: clinical presentation, diagnosis, treatment, and prevention Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine, the Gastroenterological Scientific Society of Russia, and the North- West Society of Gastroenterologists and Hepatologists

   Clinical guidelines are intended for gastroenterologists, internists, and general practitioners and focus primarily on the management of patients with symptomatic uncomplicated diverticular disease, as well as on the primary and secondary prevention of acute diverticulitis and other complications of diverticular disease. Clinical guidelines were developed by the Russian Scientific Medical Society of Internal Medicine, the Gastroenterological Scientifi c Society of Russia, and the North-West Society of Gastroenterologists and Hepatologists. One of the reasons for creating new clinical guidelines is that the current guidelines on diverticular disease (2021) pay much more attention to complications of diverticular disease and surgical treatment of acute and chronic complications of the disease.

Colonic diverticular disease: clinical presentation, diagnosis, treatment, and prevention Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine, the Gastroenterological Scientific Society of Russia, and the North- West Society of Gastroenterologists and Hepatologists

   Clinical guidelines are intended for gastroenterologists, internists, and general practitioners and focus primarily on the management of patients with symptomatic uncomplicated diverticular disease, as well as on the primary and secondary prevention of acute diverticulitis and other complications of diverticular disease. Clinical guidelines were developed by the Russian Scientific Medical Society of Internal Medicine, the Gastroenterological Scientifi c Society of Russia, and the North-West Society of Gastroenterologists and Hepatologists. One of the reasons for creating new clinical guidelines is that the current guidelines on diverticular disease (2021) pay much more attention to complications of diverticular disease and surgical treatment of acute and chronic complications of the disease.

Metabotropic 5-HT receptor-mediated effects in the human submucous plexus

BACKGROUND

Serotonin (5-HT) is an important mediator in the gastrointestinal tract, acting on different neuronal 5-HT receptors. The ionotropic 5-HT₃ receptor mediates immediate but transient spike discharge in human enteric neurons. We studied the role of the metabotropic 5-HT_1P , 5-HT₄ , and 5-HT₇ receptors to activate human submucous neurons.

METHODS

Neuroimaging using the voltage sensitive dye Di-8-ANEPPS was performed in submucous plexus preparations from human surgical specimens of the small and large intestine. We synthesized a new, stable 5-HT_1P agonist, 5-benzyloxyhydrazonoindalpine (5-BOHIP).

KEY RESULTS

5-HT evoked a fast and late-onset spike discharge in enteric neurons. The fast component was blocked by the 5-HT₃ receptor antagonist cilansetron, while the remaining sustained response was significantly reduced by the 5-HT_1P receptor antagonist 5-hydroxytryptophanyl-5-hydroxytryptophan amide (5-HTP-DP). The newly synthesized 5-HT_1P agonist 5-BOHIP induced a slowly developing, long-lasting activation of submucous neurons, which was blocked by 5-HTP-DP. We could not demonstrate any 5-HT₇ receptor-induced spike discharge based on the lack of response to 5-carboxamidotryptamine. Similarly, the 5-HT₄ agonists 5-methoxytryptamine and prucalopride evoked no immediate or late-onset spike discharge.

CONCLUSIONS & INFERENCES

Our work demonstrated for the first time the presence of functional 5-HT_1P receptors on human submucous neurons. Furthermore, we found no evidence for a role of 5-HT₄ or 5-HT₇ receptors in the postsynaptic activation of human submucous neurons by 5-HT.

Oxidative imbalance and muscular alterations in diverticular disease

BACKGROUND

It is still a matter of debate if neuromuscular alterations reflect a primary event in diverticular disease (DD).

AIMS

This study aimed to assess colonic wall layers from both stenotic and non-stenotic complicated DD, bio-phenotypic alterations, inflammatory and oxidative status.

METHODS

A systematic analysis of colonic specimens obtained from stenotic and non-stenotic DD specimens was conducted and compared with controls. Biological activity and qPCR analysis were performed on longitudinal and circular muscles. Western blot analysis was performed throughout colonic wall layers to quantify oxidative and inflammatory markers.

RESULTS

A homogenous increase in oxidative stress was observed through all the layers, which were more sharpened in the longitudinal muscle for a loss in antioxidant defenses. In both stenotic and non-stenotic colon, the longitudinal muscle presented an impaired relaxation and a cellular phenotypic switch driven by transforming growth factor-β with an increase in mRNA expression of collagen Iα and a decrease in myosin heavy chain. The circular muscle, as the mucosa, was less affected by molecular alterations. No peculiar increase in inflammatory markers was observed.

CONCLUSION

A longitudinal colonic myopathy is present in DD, independently from the disease stage associated with an oxidative imbalance that could suggest new therapeutic strategies.

Pathophysiology of Diverticular Disease: From Diverticula Formation to Symptom Generation

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

The prevalence of symptomatic uncomplicated diverticular disease could be lower than expected: a single-center colonoscopy-based cohort study

AIM

The real prevalence of symptomatic uncomplicated diverticular disease (SUDD) is still unknown. The aim of this study was to assess the prevalence of SUDD, post-diverticulitis SUDD (PD-SUDD) and irritable bowel syndrome (IBS)-like symptoms in a real-life population.

METHODS

A cohort of patients, submitted to colonoscopy from 1st January 2012 to 30th April 2018 was revised.

RESULTS

A cohort of 5451 patients with diverticulosis was identified during the study period. Abdominal pain was recorded in 1141 patients (20.93%), diarrhea in 288 (5.28%) and constipation in 536 (9.83%) patients. SUDD was recorded in 371 patients (6.81% of the patients having diverticulosis and 32.51% of the patients experiencing abdominal pain), PD-SUDD was recorded in 103 patients (1.89% of the patients having diverticulosis and 9.03% of the patients experiencing abdominal pain) and IBS-like was recorded in 348 patients (6.38% of the patients having diverticulosis and 30.5% of the patients experiencing abdominal pain). Three hundred and nineteen patients were not part of any of the previous categories (5.85% of the patients having diverticulosis and 27.96% of the patients experiencing abdominal pain). SUDD and PD-SUDD were more frequent in older ages (>60 years), while IBS-like symptoms were more frequent in younger. Nonspecific abdominal pain was equally distributed in through the ages.

CONCLUSION

The prevalence of SUDD seems to be lower than expected, and most of patients with diverticulosis and abdominal symptoms may suffer from IBS-like or other causes.

Chronic constipation is negatively associated with colonic diverticula

OBJECTIVES

Constipation has been considered the key risk factor for diverticulosis occurrence, but the underlying mechanism is unclear. We investigated the factors associated with diverticulosis, focusing on the association of constipation severity with the localization and number of diverticula.

MATERIALS AND METHODS

We analyzed consecutive patients who underwent colonoscopy between March and December 2019. Chronic constipation was diagnosed as constipation meeting Rome IV criteria or as that requiring laxative therapy for more than 6 months. The degree of constipation was scored using the Constipation Scoring System (CSS).

RESULTS

We assessed 1014 patients. Multivariate analysis revealed that age, alcohol consumption, and hypertension were positively associated with diverticulosis, whereas chronic constipation was negatively associated with diverticulosis (odds ratio [OR] = 0.74; 95% confidence interval [CI], 0.55-0.99). When assessed according to the location of diverticula, right-sided diverticula were significantly associated with a lower incidence of constipation (OR = 0.94; 95% CI, 0.89-0.98), whereas neither left-sided nor bilateral diverticula was associated with constipation. This negative association of diverticula with constipation was stronger in patients with a high CSS score. In stratified analysis, the number of diverticula decreased with increasing degree of constipation (p for trend <.01), and a high CSS score was associated with a decreased prevalence of ≥3 diverticula (OR = 0.64; 95% CI, 0.44-0.99).

CONCLUSIONS

Chronic constipation was negatively associated with colonic diverticulosis. The association increased with the degree of constipation and was strong only in cases with right-sided diverticula and those with ≥3 diverticula.

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

BACKGROUND

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

AIM

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

METHODS AND RESULTS

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

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Acute diverticulitis: old challenge, current trends, open questions

Acute diverticulitis (AD) is an increasing issue for health systems worldwide. As accuracy of clinical symptoms and laboratory examinations is poor, a pivotal role in preoperative diagnosis and severity assessment is played by CT scan. Several new classifications trying to adapt the intraoperative Hinchey's classification to preoperative CT findings have been proposed, but none really entered clinical practice. Treatment of early AD is mostly conservative (antibiotics) and may be administered in outpatients in selected cases. Larger abscesses (exceeding 3 to 5 cm) need percutaneous drainage, while management of stages 3 (purulent peritonitis) and 4 (fecal peritonitis) is difficult to standardize, as various approaches are nowadays suggested. Three situations are identified: situation A, stage 3 in stable/healthy patients, where various options are available, including conservative management, lavage/drainage and primary resection/anastomosis w/without protective stoma; situation B, stage 3 in unstable and/or unhealthy patients, and stage 4 in stable/healthy patients, where stoma-protected primary resection/anastomosis or Hartmann procedure should be performed; situation C, stage 4 in unstable and/or unhealthy patients, where Hartmann procedure or damage control surgery (resection without any anastomosis/stoma) are suggested. Late, elective sigmoid resection is less and less performed, as a new trend towards a patient-tailored management is spreading.

Intestinal epithelial barrier and neuromuscular compartment in health and disease

A number of digestive and extra-digestive disorders, including inflammatory bowel diseases, irritable bowel syndrome, intestinal infections, metabolic syndrome and neuropsychiatric disorders, share a set of clinical features at gastrointestinal level, such as infrequent bowel movements, abdominal distension, constipation and secretory dysfunctions. Several lines of evidence indicate that morphological and molecular changes in intestinal epithelial barrier and enteric neuromuscular compartment contribute to alterations of both bowel motor and secretory functions in digestive and extra-digestive diseases. The present review has been conceived to provide a comprehensive and critical overview of the available knowledge on the morphological and molecular changes occurring in intestinal epithelial barrier and enteric neuromuscular compartment in both digestive and extra-digestive diseases. In addition, our intent was to highlight whether these morphological and molecular alterations could represent a common path (or share some common features) driving the pathophysiology of bowel motor dysfunctions and related symptoms associated with digestive and extra-digestive disorders. This assessment might help to identify novel targets of potential usefulness to develop original pharmacological approaches for the therapeutic management of such disturbances.

Etiopathogenetic Mechanisms in Diverticular Disease of the Colon

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

Persistent Increased Enteric Glial Expression of S100β is Associated With Low-grade Inflammation in Patients With Diverticular Disease

BACKGROUND

Diverticular disease (DD) is a common gastrointestinal inflammatory disorder associated with an enteric neuropathy. Although enteric glial cells (EGCs) are essential regulators of intestinal inflammation and motility functions, their contribution to the pathophysiology of DD remains unclear. Therefore, we analyzed the expression of specific EGC markers in patients with DD.

MATERIALS AND METHODS

Expression of the glial markers S100β, GFAP, Sox10, and Connexin 43 was analyzed by real-time quantitative PCR in colonic specimens of patients with DD and in that of controls. Protein expression levels of S100β, GFAP, and Connexin 43 were further analyzed using immunohistochemistry in the submucosal and myenteric plexus of patients with DD and in that of controls. Expression of the inflammatory cytokines tumor necrosis factor-α and interleukin-6 was quantified using qPCR, and infiltration of CD3+ lymphocytes was determined using immunohistochemistry.

RESULTS

Expression of S100β was increased in the submucosal and myenteric plexus of patients with DD compared with that in controls, whereas expression of other glial factors remained unchanged. This increased expression of S100β was correlated to CD3+ lymphocytic infiltrates in patients with DD, whereas no correlation was observed in controls.

CONCLUSIONS

DD is associated with limited but significant alterations of the enteric glial network. The increased expression of S100β is associated with a persistent low-grade inflammation reported in patients with DD, further emphasizing the role of EGCs in intestinal inflammation.

Epidemiology, Pathophysiology, and Treatment of Diverticulitis

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

Role of Inflammation in the Pathogenesis of Diverticular Disease

Diverticulosis of the colon is the most common condition in Western societies and it is the most common anatomic alteration of the human colon. Recurrent abdominal pain is experienced by about 20% of patients with diverticulosis, but the pathophysiologic mechanisms of its occurrence are not completely understood. In the last years, several fine papers have showed clearly the role of low-grade inflammation both in the occurrence of symptoms in people having diverticulosis, both in symptom persistence following acute diverticulitis, even if the evidence available is not so strong. We do not know yet what the trigger of this low-grade inflammation occurrence is. However, some preliminary evidence found colonic dysbiosis linked to low-grade inflammation and therefore to symptom occurrence in those patients. The aim of this paper is to summarize current evidences about the role of inflammation in symptom occurrence in symptomatic uncomplicated diverticular disease and in symptom persistence after an episode of acute diverticulitis.

Altered enteric expression of the homeobox transcription factor Phox2b in patients with diverticular disease

Background

Diverticular disease, a major gastrointestinal disorder, is associated with modifications of the enteric nervous system, encompassing alterations of neurochemical coding and of the tyrosine receptor kinase Ret/GDNF pathway. However, molecular factors underlying these changes remain to be determined.

Objectives

We aimed to characterise the expression of Phox2b, an essential regulator of Ret and of neuronal subtype development, in the adult human enteric nervous system, and to evaluate its potential involvement in acute diverticulitis.

Methods

Site-specific gene expression of Phox2b in the adult colon was analysed by quantitative polymerase chain reaction. Colonic specimens of adult controls and patients with diverticulitis were subjected to quantitative polymerase chain reaction for Phox2b and dual-label immunochemistry for Phox2b and the neuronal markers RET and tyrosine hydroxylase or the glial marker S100β.

Results

The results indicate that Phox2b is physiologically expressed in myenteric neuronal and glial subpopulations in the adult enteric nervous system. Messenger RNA expression of Phox2b was increased in patients with diverticulitis and both neuronal, and glial protein expression of Phox2b were altered in these patients.

Conclusions

Alterations of Phox2b expression may contribute to the enteric neuropathy observed in diverticular disease. Future studies are required to characterise the functions of Phox2b in the adult enteric nervous system and to determine its potential as a therapeutic target in gastrointestinal disorders.

Diverticulosis today

The incidence of diverticulosis and diverticular disease of the colon is increasing worldwide. Although the majority of patients remains asymptomatic long-life, the prevalence of diverticular disease of the colon, including acute diverticulitis, is substantial and is becoming a significant burden on National Health Systems in terms of direct and indirect costs. Fiber, non-absorbable antibiotics and probiotics seem to be effective in treating symptomatic and uncomplicated patients, and 5-aminosalicylic acid might help prevent acute diverticulitis. Unfortunately, robust evidence on the effectiveness of a medical strategy to prevent acute diverticulitis recurrence is still lacking. Focus is now being drawn on identifying a new endoscopic classification of the disease to evaluate the correct therapeutic approach by testing various treatments.

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

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

A critical appraisal of advances in the diagnosis of diverticular disease

Diverticulosis of the colon is a common condition, and about one-fourth of those people develop symptoms, which is called 'diverticular disease' (DD). Since there are still some concerns about the diagnosis of DD, the aim of this review was to analyze current and evolving advances in its diagnosis. Area covered: Analysis of clinical, radiology, laboratory, and endoscopic tools to pose a correct diagnosis of DD was performed according to current PubMed literature. Expert commentary: A combination of clinical characteristic of the abdominal pain and fecal calprotectin expression may help to differentiate between symptomatic uncomplicated diverticular disease and irritable bowel syndrome. Abdominal computerized tomography (CT) scan is still the gold standard in diagnosing acute diverticulitis and its complications. CT-colonography may be useful as a predicting tool on the outcome of the disease. Diverticular Inflammation and Complications Assessment (DICA) endoscopic classification shows a significant relationship between severity of DICA score inflammatory indexes, as well as with severity of abdominal pain. Moreover, it seems to be predictive of the outcome of the disease in terms of acute diverticulitis occurrence/recurrence and surgery occurrence. Finally, preliminary data found intestinal microbiota analysis is a promising tool in diagnosing and monitoring this disease.

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.

Association between endoscopic findings related to colonic diverticula and bowel habits: A multicenter study in Japan

BACKGROUND AND AIM

Few studies have shown the associations between colonic diverticula and endoscopic findings such as location, inflammation, number of diverticula, sigmoid colon rigidity, and bowel habits.

METHODS

Japanese subjects who underwent total colonoscopies at six centers in Japan from November 2015 to October 2016 were analyzed. Bowel habits were evaluated using the Gastrointestinal Symptom Rating Scale. Location and number of diverticula, inflammation, and sigmoid colon rigidity were evaluated from endoscopy results.

RESULTS

A total of 762 subjects (486 men and 276 women [ratio, 1.76:1]) whose mean age was 65.5 ± 11.4 years were evaluated. In multivariate analysis, presence of constipation was associated with a significantly lower likelihood of left-sided colonic diverticula (odds ratio = 0.40, 95% confidence interval 0.20-0.82, P = 0.012), whereas right-sided and bilateral-sided colonic diverticula, multiple colonic diverticula, inflammation findings, and sigmoid colon rigidity were not related to bowel habits.

CONCLUSIONS

Among endoscopic findings related to colonic diverticula and bowel habits, only left-sided colonic diverticula were inversely associated with constipation, whereas inflammation findings, multiple diverticula, and sigmoid colon rigidity were not related to bowel habits. However, the association of inflammation findings with colonic diverticula and bowel habits should be further studied. Investigation of changes in left-sided colonic diverticula may lead to new treatments for constipation.

Nicotinamide adenine dinucleotide replenishment rescues colon degeneration in aged mice

Susceptibility of gastrointestinal dysmotility increases with age-associated colonic degeneration. A paucity of remedies reversing colonic degeneration per se hinders the fundamental relief of symptoms. Here we discovered the correlation between colon degeneration and altered nicotinamide adenine dinucleotide (NAD) level in aged mice. Compared to 3-month-old young controls, 2-year-old mice showed a spectrum of degenerative colonic phenotypes and exhibited a significant elongated transit time and slowed stool frequency in the context of Lomotil-induced slow-transit constipation. Despite upregulated colonic tryptophan hydroxylases expression, serotonin release and expression of colon-predominant type IV serotonin receptor, reduced viability of interstitial cells of Cajal while enhanced aquaporins (Aqp1, 3 and 11) led to a less colonic motility and increased luminal dehydration in aged mice. Notably, this colonic degeneration was accompanied with reduced key NAD⁺-generating enzyme expression and lowered NAD⁺/NADH ratio in aged colon. Three-month continuous administration of beta nicotinamide mononucleotide, a NAD⁺ precursor, elevated colonic NAD⁺ level and improved defecation in aged mice. In contrast, pharmacological inhibition of nicotinamide phosphoribosyltransferase, the rate-limiting enzyme for NAD⁺ biosynthesis, induced a reduction in colonic NAD content and impaired gastrointestinal function in young mice. Taken together, these findings suggest the beneficial effect of NAD⁺ in maintaining colonic homoeostasis and reactivating NAD⁺ biosynthesis may represent a promising strategy to counteract age-related gastrointestinal degeneration.

Gut microbiota, metabolome and immune signatures in patients with uncomplicated diverticular disease

OBJECTIVE

The engagement of the gut microbiota in the development of symptoms and complications of diverticular disease has been frequently hypothesised. Our aim was to explore colonic immunocytes, gut microbiota and the metabolome in patients with diverticular disease in a descriptive, cross-sectional, pilot study.

DESIGN

Following colonoscopy with biopsy and questionnaire phenotyping, patients were classified into diverticulosis or symptomatic uncomplicated diverticular disease; asymptomatic subjects served as controls. Mucosal immunocytes, in the diverticular region and in unaffected sites, were quantified with immunohistochemistry. Mucosa and faecal microbiota were analysed by the phylogenetic platform high taxonomic fingerprint (HTF)-Microbi.Array, while the metabolome was assessed by ¹H nuclear magnetic resonance.

RESULTS

Compared with controls, patients with diverticula, regardless of symptoms, had a >70% increase in colonic macrophages. Their faecal microbiota showed depletion of Clostridium cluster IV. Clostridium cluster IX, Fusobacterium and Lactobacillaceae were reduced in symptomatic versus asymptomatic patients. A negative correlation was found between macrophages and mucosal Clostridium cluster IV and Akkermansia. Urinary and faecal metabolome changes in diverticular disease involved the hippurate and kynurenine pathways. Six urinary molecules allowed to discriminate diverticular disease and control groups with >95% accuracy.

CONCLUSIONS

Patients with colonic diverticular disease show depletion of microbiota members with anti-inflammatory activity associated with mucosal macrophage infiltration. Metabolome profiles were linked to inflammatory pathways and gut neuromotor dysfunction and showed the ability to discriminate diverticular subgroups and controls. These data pave the way for further large-scale studies specifically aimed at identifying microbiota signatures with a potential diagnostic value in patients with diverticular disease.

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.

Diverticulosis today: unfashionable and still under-researched

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

Effects of Amoxicillin and Clavulanic Acid on the Spontaneous Mechanical Activity of Juvenile Rat Duodenum

OBJECTIVES

There are a limited number of medications for the treatment of foregut dysmotility. Enteral amoxicillin/clavulanic acid induces phase III duodenal contractions in a fasting pediatric patient. The mechanism by which this occurs is unknown. We examined the individual contributions of amoxicillin and clavulanic acid on the spontaneous mechanical activity of juvenile rat duodenum to better understand this phenomenon.

METHODS

Duodenal segments from juvenile rats were longitudinally attached to force transducers in organ baths. Samples were cumulatively exposed to amoxicillin or clavulanic acid. Separate samples were exposed to carbachol alone to assess response in both the presence and absence of amoxicillin or clavulanic acid. Basal tone, frequency, and amplitude of contractions were digitized and recorded.

RESULTS

The amplitude of the spontaneous contractions increased with amoxicillin. Inhibition of neuronal activity prevented this effect. Clavulanic acid did not affect the spontaneous contractions. Basal tone and the rate of contractions did not differ with either drug. Stimulation with carbachol in the presence of amoxicillin caused a statistically significant increase in the contractility compared with carbachol alone.

CONCLUSIONS

Amoxicillin alters the spontaneous longitudinal mechanical activity of juvenile rat duodenum. Our results suggest that amoxicillin modulates the spontaneous pattern of cyclic mechanical activity of duodenal smooth muscle through noncholinergic, neurally mediated mechanisms. Our work provides an initial physiologic basis for the therapeutic use of amoxicillin in patients with gastrointestinal dysmotility.

Diverticular disease: guidelines of the german society for gastroenterology, digestive and metabolic diseases and the german society for general and visceral surgery

BACKGROUND

Diverticular disease is one of the most common disorders of the gastrointestinal tract. 28-45% of the population develop colonic diverticula, while about 25% suffer symptoms and about 5% complications.

AIM

To create formal guidelines for diagnosis and management.

METHODS

Six working groups with 44 participants analyzed key questions in subject areas assigned to them. Following a systematic literature search, 451 publications were included. Consensus was obtained by agreement within the working groups, two Delphi processes and a guideline conference.

RESULTS

Targeted management of diverticular disease requires a classificatory diagnosis. A new classification was created. In addition to the clinical examination, intestinal ultrasound or computed tomography is the determining factor. Interval colonoscopy is recommended to exclude comorbidities. A low-fiber diet, obesity, lack of exercise, smoking and immunosuppression have an adverse impact on diverticulosis. This can lead to diverticulitis. Antibiotics are no longer recommended in uncomplicated diverticulitis if no risk factors such as immunosuppression are present. If close monitoring is ensured, uncomplicated diverticulitis can be treated on an outpatient basis. Complicated diverticulitis should be treated in hospital, involving broad-spectrum antibiotic therapy, where necessary abscess drainage, and surgery, if possible laparoscopically. In the case of chronic relapsing diverticulitis, the risk of perforation decreases with each episode, so that surgery is no longer recommended after the second episode but only following individual assessment.

CONCLUSIONS

New findings on diverticular disease call into question the overuse of antibiotics and excessive indications for surgery. Targeted treatment requires a precise diagnosis and intensive interdisciplinary cooperation.

Morphologic Basis for Developing Diverticular Disease, Diverticulitis, and Diverticular Bleeding

Diverticula of the colon are pseudodiverticula defined by multiple outpouchings of the mucosal and submucosal layers penetrating through weak spots of the muscle coat along intramural blood vessels. A complete prolapse consists of a diverticular opening, a narrowed neck, and a thinned diverticular dome underneath the serosal covering. The susceptibility of diverticula to inflammation is explained by local ischemia, translocation of pathogens due to retained stool, stercoral trauma by fecaliths, and microperforations. Local inflammation may lead to phlegmonous diverticulitis, paracolic/mesocolic abscess, bowel perforation, peritonitis, fistula formation, and stenotic strictures. Diverticular bleeding is due to an asymmetric rupture of distended vasa recta at the diverticular dome and not primarily linked to inflammation. Structural and functional changes of the bowel wall in diverticular disease comprise: i) Altered amount, composition, and metabolism of connective tissue; ii) Enteric myopathy with muscular thickening, deranged architecture, and altered myofilament composition; iii) Enteric neuropathy with hypoganglionosis, neurotransmitter imbalance, deficiency of neurotrophic factors and nerve fiber remodeling; and iv) Disturbed intestinal motility both in vivo (increased intraluminal pressure, motility index, high-amplitude propagated contractions) and in vitro (altered spontaneous and pharmacologically triggered contractility). Besides established etiologic factors, recent studies suggest that novel pathophysiologic concepts should be considered in the pathogenesis of diverticular disease.

Diverticular disease as a chronic gastrointestinal condition: experience from a specialist clinic

BACKGROUND

Although diverticular disease is a prevalent condition and a significant burden on the healthcare system, care is devolved across gastrointestinal, GP, and colorectal surgery clinics. We created a specialist Diverticular Disease Clinic to streamline care, enhance evidence-based practice and provide a base for research. The aim of this study was to assess patient referral sources, predictors of persistent disease and surgical outcomes.

METHODS

We retrospectively reviewed all patients attending our clinic. Patients younger than 50 years of age on initial presentation were considered 'younger' patients. Persistent symptoms lasted for at least 3 months.

RESULTS

Overall, 177 patients had confirmed diverticular disease. Patients were referred following hospital admission (82 patients, 46.3%) or from the community (95 patients, 53.7%). Ninety-five patients (53.7%) had persistent symptoms. Patients with more than two episodes of diverticulitis were more likely to have persistent symptoms (P<0.0001).Following hospitalization, younger patients were 3.98 times more likely to develop persistent symptoms (P=0.04). This was independent of the severity of the original infection, as a low peak C-reactive protein level of less than 50 mg/L was associated with persistent symptoms (odds ratio=3.62, P=0.03). Over the study period, 12 patients (6.9%) had elective surgery.

CONCLUSION

There is demand for dedicated care for patients with persistent symptoms from diverticular disease. Specialized clinics are a model for this care, provided by either gastroenterologists or surgeons, in centres with adequate demand. Our findings reinforce the hypotheses that chronic abdominal pain in diverticular disease may be related to sensation abnormalities similar to postinfective irritable bowel syndrome.

Changing views on diverticular disease: impact of aging, obesity, diet, and microbiota

The development of colonic diverticulosis is a common aging change in industrialized nations. While most patients have asymptomatic diverticulosis, around one in five develops symptomatic diverticular disease. This is characterized by recurrent abdominal pain and disturbed bowel habit. Some of the pain episodes are prolonged and are due to acute diverticulitis, which itself may be complicated by abscess, perforation, fistulation, or stricture formation. Risk factors favouring the development of symptomatic diverticular disease include obesity, smoking and diets low in fiber but high in red meat and animal fat. What determines the transition from asymptomatic diverticulosis to symptomatic diverticular disease is unclear but neuromuscular changes following acute diverticulitis may be responsible in some cases. The severity of symptoms generated depends on cerebral pain processing which is influenced by psychosocial factors. These are important considerations in deciding optimal patient management. Prior theories of the cause of diverticulosis suggested that constipation was an important cause, but new data challenge this and has provoked new ideas. Underlying mechanisms causing diverticulosis include weakening of the colonic wall and/or degenerative changes in the enteric nerves. Dietary induced changes in microbiota and the host inflammatory response may underlie the subsequent development of acute/chronic diverticulitis and its sequela.

[Anatomy and pathogenesis of diverticular disease]

BACKGROUND

Although diverticular disease is one of the most frequent gastrointestinal disorders the pathogenesis is not yet sufficiently clarified.

OBJECTIVES

The aim is to define the anatomy and pathogenesis of diverticular disease considering the risk factors and description of structural and functional alterations of the bowel wall.

METHODS

This article gives an appraisal of the literature, presentation and evaluation of classical etiological factors, analysis and discussion of novel pathogenetic concepts.

RESULTS

Colonic diverticulosis is defined as an acquired out-pouching of multiple and initially asymptomatic pseudodiverticula through muscular gaps in the colon wall. Diverticular disease is characterized by diverticular bleeding and/or inflammatory processes (diverticulitis) with corresponding complications (e.g. abscess formation, fistula, covered and open perforation, peritonitis and stenosis). Risk factors for diverticular disease include increasing age, genetic predisposition, congenital connective tissue diseases, low fiber diet, high meat consumption and pronounced overweight. Alterations of connective tissue cause a weakening of preformed exit sites of diverticula and rigidity of the bowel wall with reduced flexibility. It is assumed that intestinal innervation disorders and structural alterations of the musculature induce abnormal contractile patterns with increased intraluminal pressure, thereby promoting the development of diverticula. Moreover, an increased release of pain-mediating neurotransmitters is considered to be responsible for persistent pain in chronic diverticular disease.

CONCLUSIONS

According to the present data the pathogenesis of diverticular disease cannot be attributed to a single factor but should be considered as a multifactorial event.

Italian consensus conference for colonic diverticulosis and diverticular disease

The statements produced by the Consensus Conference on Diverticular Disease promoted by GRIMAD (Gruppo Italiano Malattia Diverticolare, Italian Group on Diverticular Diseases) are reported. Topics such as epidemiology, risk factors, diagnosis, medical and surgical treatment of diverticular disease (DD) in patients with uncomplicated and complicated DD were reviewed by a scientific board of experts who proposed 55 statements graded according to level of evidence and strength of recommendation, and approved by an independent jury. Each topic was explored focusing on the more relevant clinical questions. Comparison and discussion of expert opinions, pertinent statements and replies to specific questions, were presented and approved based on a systematic literature search of the available evidence. Comments were added explaining the basis for grading the evidence, particularly for controversial areas.

Nitrergic neuro-muscular transmission is up-regulated in patients with diverticulosis

BACKGROUND

Neuro-transmission impairment could be associated to motility changes observed in patients with diverticular disease. Therefore, the objective was to characterize the inhibitory neuro-muscular transmission and gene expression changes of the enteric inhibitory pathways in patients with diverticulosis (DS).

METHODS

Circular muscle strips from sigmoid colon of patients with DS and controls were studied using the organ bath technique to evaluate spontaneous contractility and enteric motor neurons stimulated by electrical field and qRT-PCR to assess the expression of nNOS, iNOS, P2Y1 R and PGP9.5.

KEY RESULTS

Patients with DS presented decreased spontaneous rhythmic contractions (SRC) that were significantly enhanced after incubation with L-NNA (1 mM) and TTX (1 μM), and unaffected by the P2Y1 antagonist MRS2500 (1 μM). Stimulation on enteric motor neurons caused an increased duration of the latency of OFF-contractions in DS group (p < 0.001), antagonized by L-NNA and slightly affected by MRS2500 (1 μM). No differences in the IC50 between controls and DS patients were observed on inhibition of SRC for the NO-donor sodium nitroprusside (SNP) and the preferential P2Y agonist ADPβS. Moreover, nNOS relative expression was also up-regulated 2.3-fold in the DS group (p < 0.05) whereas there was no significant difference in relative expression of iNOS, P2Y1 R and the neuronal marker PGP9.5 between groups.

CONCLUSIONS & INFERENCES

Patients with DS presented an over-expression of nNOS with increased endogenously NO-mediated responses suggesting enhanced NO-release. Up-regulation in the nitrergic pathway in early stages of the disease might play a role in colonic motor disorders associated to diverticular disease.

Alterations of the enteric smooth musculature in diverticular disease

BACKGROUND

The pathogenesis of diverticular disease (DD) is considered to be multifactorial and involves intestinal motor disturbances and an underlying enteric neuromuscular pathology. While an enteric neuropathy has been well documented, actual studies on concomitant alterations of the enteric musculature are limited. This study is aimed at reassessing the smooth muscle tissue by histological, ultrastructural and molecular-biological approaches.

METHODS

Full-thickness sigmoid specimens were obtained from patients with DD (n = 20) and controls (n = 19). Morphometric analysis was performed to evaluate the thickness and connective tissue index of the circular and longitudinal muscle layers as well as the myenteric plexus. Structural alterations were determined by light and transmission electron microscopy. mRNA profiles of components of the contractile smooth muscle apparatus including smooth muscle α-actin, smoothelin, histone deacetylase 8, and smooth muscle myosin heavy chain (SMMHC) were assessed by qPCR. Altered gene expression levels were confirmed at protein level by immunohistochemistry.

RESULTS

Compared to controls, patients with DD showed (1) increased thickness of the circular and longitudinal muscle layers, (2) architectural alterations of smooth muscle cells, (3) increased connective tissue index of the longitudinal muscle layer, (4) focally reduced density of myofilaments at ultrastructural level, (5) specific down-regulation of SMMHC mRNA levels, (6) decreased immunoreactivity of SMMHC, (7) oligo-neuronal hypoganglionosis.

CONCLUSIONS

DD is associated with distinct structural and functional alterations of the enteric musculature. The enteric myopathy is characterized by disturbed muscular architecture, connective tissue replacement and loss of specific myofilaments and thus may contribute to the pathogenesis and progression of DD.