Charles H. Knowles

Vanilloid receptor 1 immunoreactivity in inflamed human bowel

Vanilloid receptor 1 (VR1) is expressed by sensory neurons. Once activated, these neurons evoke the sensation of burning pain and release neuropeptides that induce neurogenic inflammation. We used immunoblotting and immunostaining to estimate the density of VR1 in colonic tissues of patients with inflammatory bowel disease and of controls. Our study results indicate that VR1 immunoreactivity is greatly increased in colonic nerve fibres of patients with active inflammatory bowel disease. Thus, the discovery of new drugs that can bind the VR1 receptor, or antagonise endogenous inflammatory substances that activate this receptor, could lead to new therapies for pain and dysmotility.

Differential regulation of interleukin 17 and interferon γ production in inflammatory bowel disease

Background and Aims: Interleukin 17 (IL17) is now known to be involved in a number of chronic inflammatory disorders. However, the mechanisms regulating its production in inflammatory bowel disease (IBD) are still unclear. Methods: Endoscopic biopsies or surgical specimens were taken from inflamed and uninflamed colonic mucosa of 72 patients with IBD (38 with Crohn’s disease and 34 with ulcerative colitis), and normal colon of 38 control subjects. IL17 and interferon γ (IFNγ) were detected by ELISA in the supernatants of biopsies cultured ex vivo, and anti-CD3/CD28-stimulated lamina propria mononuclear cells (LPMCs) incubated with IL12, IL23, IL1β plus IL6, transforming growth factor β1 (TGFβ1), or anti-IL21 neutralising antibody. Intracellular flow cytometry was performed to analyse mucosal Th17 and Th1/Th17 cells. Results: IL17 production by organ culture biopsies was higher in IBD inflamed mucosa than IBD uninflamed mucosa and controls, and was equivalent in amount to IFNγ. Anti-CD3/CD28-stimulated IBD LPMCs produced higher IL17 amounts compared to controls. The percentages of Th17 and Th1/Th17 cells were increased in patients with IBD. IL23 and IL1β plus IL6 had no effect on IBD LPMC production of IL17; however, IL12 markedly increased IFNγ production and decreased IL17 production. TGFβ1 dose-dependently decreased IFNγ, but had no significant inhibitory effect on IL17 production. Blocking IL21 significantly downregulated IL17 production. Conclusions: Our findings support a role for IL12, TGFβ and IL21 in modulating IL17/IFNγ production in IBD. The abundant IL17 in inflamed IBD mucosa may help explain the relative lack of efficacy of anti-IFNγ antibodies in clinical trials of Crohn’s disease.

Outcome of Colectomy for Slow Transit Constipation

OBJECTIVE To review the outcome data for colectomy performed for patients with slow transit constipation (STC). BACKGROUND The outcome of surgical intervention in patients with STC is unpredictable. This may be a consequence of the lack of effectiveness of such interventions or may reflect heterogeneity within this group of patients. METHODS The authors reviewed the data of all series in the English language that document the outcome of colectomy in > or = 10 patients in the treatment of STC. RESULTS Thirty-two series fulfilled the entry criteria. There was widespread variability in patient satisfaction rates after colectomy (39% to 100%), reflecting large differences in the incidence of postoperative complications and in long-term functional results. Outcome was dependent on several clinical and pathophysiologic findings and on the type of study, the population studied, and the surgical procedure used. CONCLUSIONS It may be possible to predict outcome on the basis of preoperative clinical and pathophysiologic findings. This review suggests a rationale for the selection of patients for colectomy.

The London Classification of gastrointestinal neuromuscular pathology: report on behalf of the Gastro 2009 International Working Group

Objective Guidelines on histopathological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology have been produced recently by an international working group (IWG). These addressed the important but relatively neglected areas of histopathological practice of the general pathologist, including suction rectal biopsy and full-thickness intestinal tissue. Recommendations were presented for the indications, safe acquisition of tissue, histological techniques, reporting and referral of such histological material. Design Consensual processes undertaken by the IWG and following established guideline decision group methodologies. Results and conclusion This report presents a contemporary and structured classification of gastrointestinal neuromuscular pathology based on defined histopathological criteria derived from the existing guidelines. In recognition of its origins and first presentation in London at the World Congress of Gastroenterology 2009, this has been named ‘The London Classification’. The implementation of this classification should allow some diagnostic standardisation, but should necessarily be viewed as a starting point for future modification as new data become available.

Anterior resection syndrome

Up to 80% of patients with rectal cancer undergo sphincter-preserving surgery. It is widely accepted that up to 90% of such patients will subsequently have a change in bowel habit, ranging from increased bowel frequency to faecal incontinence or evacuatory dysfunction. This wide spectrum of symptoms after resection and reconstruction of the rectum has been termed anterior resection syndrome. Currently, no precise definition or causal mechanisms have been established. This disordered bowel function has a substantial negative effect on quality of life. Previous reviews have mainly focused on different colonic reconstructive configurations and their comparative effects on daily function and quality of life. The present Review explores the potential mechanisms underlying disturbed functions, as well as current, novel, and future treatment options.

Linear discriminant analysis of symptoms in patients with chronic constipation: Validation of a new scoring system (kess)

PURPOSE: The aim of this study was to devise a symptom scoring system to assist in diagnosing constipation and in discriminating among pathophysiologic subgroups. METHOD: A structured symptom scoring questionnaire (11 questions) was completed by 71 chronically constipated patients and by 20 asymptomatic controls. The symptom score was correlated with a previously validated constipation score (Cleveland Clinic Score). All patients underwent colonic transit studies, standard anorectal physiology testing, and evacuation proctography. On the basis of these investigations alone, an observer blinded to the questionnaire results allocated patients to one of three pathophysiologic subgroups: slow-transit constipation, rectal evacuatory disorder, or mixed (slow-transit constipation and rectal evacuatory disorder). Linear discriminant analysis was used to assess the ability of different questionnaire symptoms to discriminate among these subgroups. RESULTS: Total symptom score was strongly correlated with the Cleveland Clinic Score (r=0.9). The median total score in constipated patients was 20 (range, 11–35) compared with a median of 2 in controls (range, 0–6). Discriminant analysis using cross validation estimated that pathophysiology could be predicted correctly for 55 percent (95 percent confidence interval =43–67 percent) of patients using just five symptoms. The discriminant function rarely misclassified patients with rectal evacuatory disorder as slow-transit constipation andvice versa, but could not effectively discriminate between patients with single and mixed pathologies. CONCLUSION: This new scoring system is a valid technique to assist in the diagnosis of constipation and is the first study using appropriate statistical methodology to demonstrate a discriminatory ability of multiple symptoms in constipation. At present, symptom analysis does not adequately differentiate major pathophysiologic subgroups for use in clinical practice.

Gastrointestinal neuromuscular pathology: guidelines for histological techniques and reporting on behalf of the Gastro 2009 International Working Group

The term gastrointestinal neuromuscular disease describes a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular, including interstitial cell of Cajal, dysfunction. Such disorders commonly have impaired motor activity, i.e. slowed or obstructed transit with radiological evidence of transient or persistent visceral dilatation. Whilst sensorimotor abnormalities have been demonstrated by a variety of methods in these conditions, standards for histopathological reporting remain relatively neglected. Significant differences in methodologies and expertise continue to confound the reliable delineation of normality and specificity of particular pathological changes for disease. Such issues require urgent clarification to standardize acquisition and handling of tissue specimens, interpretation of findings and make informed decisions on risk-benefit of full-thickness tissue biopsy of bowel or other diagnostic procedures. Such information will also allow increased certainty of diagnosis, facilitating factual discussion between patients and caregivers, as well as giving prognostic and therapeutic information. The following report, produced by an international working group, using established consensus methodology, presents proposed guidelines on histological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology. The report addresses the main areas of histopathological practice as confronted by the pathologist, including suction rectal biopsy and full-thickness tissue obtained with diagnostic or therapeutic intent. For each, indications, safe acquisition of tissue, histological techniques, reporting and referral recommendations are presented.

Basic and clinical aspects of gastrointestinal pain.

ABSTRACT The gastrointestinal (GI) tract is a system of organs within multicellular animals which facilitates the ingestion, digestion, and absorption of food with subsequent defecation of waste. A complex arrangement of nerves and ancillary cells contributes to the sensorimotor apparatus required to subserve such essential functions that are with the exception of the extreme upper and lower ends of the GI tract normally subconscious. However, it also has the potential to provide conscious awareness of injury. Although this function can be protective, when dysregulated, particularly on a chronic basis, the same system can lead to considerable morbidity. The anatomical and molecular basis of gastrointestinal nociception, conditions associated with chronic unexplained visceral pain, and developments in treatment are presented in this review.

Visceral hypersensitivity in non-erosive reflux disease

Non-erosive reflux disease (NERD) is defined as the presence of classic symptoms of gastro-oesophageal reflux disease (GORD) in the absence of oesophageal mucosal injury (or Barrett’s oesophagus) as determined by inspection at upper gastrointestinal endoscopy.1 As such it is regarded as being one of the two main phenotypes of GORD, the other being erosive oesophagitis (EO) where ulceration or erosions are evident. GORD is common, with estimates of 20–44% of Western populations having symptoms of GORD at least once a month and 20% weekly.2 The proportion of such patients with NERD is estimated to be between 503 and 70%.4 It is acknowledged that responses to standard acid suppressive treatments are 20–30% lower in patients with NERD than those with EO.5 Considering this, and the high prevalence of NERD, which is likely to increase in parallel with societal body mass index,6 the pathophysiological understanding of this condition remains a priority. The concept of visceral hypersensitivity (VH) is now well established in a variety of overtly inflammatory as well as functional gastrointestinal conditions.7 ,8 This review introduces the molecular and physiological basis of VH, particularly in respect of acid-sensing receptors, and presents the evidence that VH plays an important role in the pathophysiology of NERD. Within the spectrum of GORD, the pathophysiological relationship of EO and NERD remains the subject of debate.9 The classical and perhaps intuitive view that NERD is a mild form of GORD that might progress with time to EO is supported by some physiological, anatomical and histopathological findings. For instance, whilst demonstration of acid exposure is not a requirement for the definition of EO or NERD, there are studies that demonstrate that acid exposure as determined by 24 h pH studies is abnormal in only 45% of NERD patients …

ATP-gated ion channel P2X3 is increased in human inflammatory bowel disease

P2X3 is a novel ATP‐gated cation channel that is selectively expressed by small‐diameter sensory neurones in rodents, and may play a role in nociception by binding ATP released from damaged or inflamed tissues. We have studied, for the first time, P2X3 immunoreactivity in human inflammatory bowel disease, using Western blotting and immunohistochemistry. A major 66‐kDa specific protein was found by Western blotting in all colon extracts. In the inflamed group there was a significant two‐fold increase in the relative optical density of the 66‐kDa band (21.2 ± 3.1; n=8) compared to controls (11.4 ± 3.7; n=8; P=0.009). In the control colon, P2X3‐immunoreactive neurones were scattered throughout the myenteric and submucosal plexuses, with some neurones showing immunopositive axons/dendrites. The pattern of immunostaining was similar to the neuronal marker peripherin. In general, the intensity of the staining was greater in myenteric than submucosal neurones. The number of P2X3‐immunoreactive neurones was significantly increased in the myenteric plexus of inflamed colon compared to controls (n=13; P=0.01). In humans, unlike rodents, P2X3 is thus not restricted to sensory neurones. Increased P2X3 in inflamed intestine suggests a potential role in dysmotility and pain, for which it represents a new therapeutic target.