Autoantibodies in patients with gut motility disorders and enteric neuropathy

Role of autoantibodies in the pathophysiology of irritable bowel syndrome: a review

Irritable bowel syndrome (IBS) is a chronic, recurrent disorder that is characterized by abdominal pain associated with defecation. IBS was previously considered to manifest without any structural alterations until the discovery of post-infection IBS. An increasing body of published evidence indicates that immune activation plays an important role in the development of IBS. Nevertheless, the pathophysiology of IBS, including mainly visceral hypersensitivity and gastrointestinal dysmotility, has not yet been explicitly elucidated. The observation of potential inflammatory degenerative neuropathy, including neuronal degeneration, spearheaded research on autoimmune responses targeting the enteric nervous system. Subsequently, several autoantibodies were detected in the sera of IBS patients, among which some were presumed to exert a pathogenic influence or be associated with the etiology of gastrointestinal dysmotility in IBS. Moreover, certain specific autoantibodies evidently served as biomarkers to facilitate the differentiation between IBS and other related diseases. Therefore, we aimed to present an overview of autoantibodies reported in the sera of IBS patients and highlight their significance in diagnosing and comprehending the pathophysiology of IBS. Consequently, we propose a therapeutic strategy from an autoimmune perspective.

Idiopathic Slow Transit Constipation: Pathophysiology, Diagnosis, and Management

Slow transit constipation (STC) has an estimated prevalence of 2-4% of the general population, and although it is the least prevalent of the chronic constipation phenotypes, it more commonly causes refractory symptoms and is associated with significant psychosocial stress, poor quality of life, and high healthcare costs. This review provides an overview of the pathophysiology, diagnosis, and management options in STC. STC occurs due to colonic dysmotility and is thought to be a neuromuscular disorder of the colon. Several pathophysiologic features have been observed in STC, including reduced contractions on manometry, delayed emptying on transit studies, reduced numbers of interstitial cells of Cajal on histology, and reduced amounts of excitatory neurotransmitters within myenteric plexuses. The underlying aetiology is uncertain, but autoimmune and hormonal mechanisms have been hypothesised. Diagnosing STC may be challenging, and there is substantial overlap with the other clinical constipation phenotypes. Prior to making a diagnosis of STC, other primary constipation phenotypes and secondary causes of constipation need to be ruled out. An assessment of colonic transit time is required for the diagnosis and can be performed by a number of different methods. There are several different management options for constipation, including lifestyle, dietary, pharmacologic, interventional, and surgical. The effectiveness of the available therapies in STC differs from that of the other constipation phenotypes, and prokinetics often make up the mainstay for those who fail standard laxatives. There are few available management options for patients with medically refractory STC, but patients may respond well to surgical intervention. STC is a common condition associated with a significant burden of disease. It can present a clinical challenge, but a structured approach to the diagnosis and management can be of great value to the clinician. There are many therapeutic options available, with some having more benefits than others.

Chronic intestinal pseudo-obstruction in adults: A practical guide to identify patient subgroups that are suitable for more specific treatments

Chronic intestinal pseudo-obstruction is a rare and heterogeneous syndrome characterized by recurrent symptoms of intestinal obstruction with radiological features of dilated small or large intestine with air/fluid levels in the absence of any mechanical occlusive lesion. Several diseases may be associated with chronic intestinal pseudo-obstruction and in these cases, the prognosis and treatment are related to the underlying disease. Also, in its "primary or idiopathic" form, two subgroups of patients should be determined as they require a more specific therapeutic approach: patients whose chronic intestinal pseudo-obstruction is due to sporadic autoimmune/inflammatory mechanisms and patients whose neuromuscular changes are genetically determined. In a context of a widely heterogeneous adult population presenting chronic intestinal pseudo-obstruction, this review aims to summarize a practical diagnostic workup for identifying definite subgroups of patients who might benefit from more specific treatments, based on the etiology of their underlying condition.

Multiple rather than specific autoantibodies were identified in irritable bowel syndrome with HuProt™ proteome microarray

Immune activation and several autoantibodies might be involved in the pathophysiology of irritable bowel syndrome (IBS). We aimed to identify serum biomarkers for IBS by HuProt™ microarray. IBS patients met Rome III criteria were enrolled. Control groups included healthy controls (HCs) and disease controls (DCs). In stage I, we profiled sera from IBS and control groups with HuProt™ microarrays. Based on significant different proteins in stage I, IBS focused microarrays were constructed and validated in a larger cohort in stage II, then decision tree models were generated to establish a combination of biomarkers. In stage III, 4 purified proteins were verified by ELISA. Finally, we analyzed the correlation of autoantibodies with symptoms. In stage I, we identified 47 significant different proteins including 8 autoantibodies of IgG, 2 of IgA between IBS and HCs; 13 autoantibodies of IgG, 13 of IgA between IBS and DCs. In stage II, we found the positive rates of 14 IgG and IgA autoantibodies in IBS were significantly higher than HCs. Five autoantibodies of IgG and 7 IgA were comprehensively involved in differentiating IBS and HCs with the sensitivity and specificity to diagnose IBS as 40%–46.7% and 79.4%–86.3%. The median optical density value of ELAVL4 (IgG) and PIGP (IgA) were significantly higher in IBS than HCs. Parts of autoantibodies above were related to IBS symptoms. We found a combination of autoantibodies to differentiate IBS with HCs, but no specific autoantibodies could serve as serum biomarkers for IBS.

Disorders of the enteric nervous system - a holistic view

The enteric nervous system (ENS) is the largest division of the peripheral nervous system and closely resembles components and functions of the central nervous system. Although the central role of the ENS in congenital enteric neuropathic disorders, including Hirschsprung disease and inflammatory and functional bowel diseases, is well acknowledged, its role in systemic diseases is less understood. Evidence of a disordered ENS has accumulated in neurodegenerative diseases ranging from amyotrophic lateral sclerosis, Alzheimer disease and multiple sclerosis to Parkinson disease as well as neurodevelopmental disorders such as autism. The ENS is a key modulator of gut barrier function and a regulator of enteric homeostasis. A 'leaky gut' represents the gateway for bacterial and toxin translocation that might initiate downstream processes. Data indicate that changes in the gut microbiome acting in concert with the individual genetic background can modify the ENS, central nervous system and the immune system, impair barrier function, and contribute to various disorders such as irritable bowel syndrome, inflammatory bowel disease or neurodegeneration. Here, we summarize the current knowledge on the role of the ENS in gastrointestinal and systemic diseases, highlighting its interaction with various key players involved in shaping the phenotypes. Finally, current flaws and pitfalls related to ENS research in addition to future perspectives are also addressed.

The enteric nervous system in gastrointestinal disease etiology

A highly conserved but convoluted network of neurons and glial cells, the enteric nervous system (ENS), is positioned along the wall of the gut to coordinate digestive processes and gastrointestinal homeostasis. Because ENS components are in charge of the autonomous regulation of gut function, it is inevitable that their dysfunction is central to the pathophysiology and symptom generation of gastrointestinal disease. While for neurodevelopmental disorders such as Hirschsprung, ENS pathogenesis appears to be clear-cut, the role for impaired ENS activity in the etiology of other gastrointestinal disorders is less established and is often deemed secondary to other insults like intestinal inflammation. However, mounting experimental evidence in recent years indicates that gastrointestinal homeostasis hinges on multifaceted connections between the ENS, and other cellular networks such as the intestinal epithelium, the immune system, and the intestinal microbiome. Derangement of these interactions could underlie gastrointestinal disease onset and elicit variable degrees of abnormal gut function, pinpointing, perhaps unexpectedly, the ENS as a diligent participant in idiopathic but also in inflammatory and cancerous diseases of the gut. In this review, we discuss the latest evidence on the role of the ENS in the pathogenesis of enteric neuropathies, disorders of gut-brain interaction, inflammatory bowel diseases, and colorectal cancer.

The management of adult patients with severe chronic small intestinal dysmotility

Adult patients with severe chronic small intestinal dysmotility are not uncommon and can be difficult to manage. This guideline gives an outline of how to make the diagnosis. It discusses factors which contribute to or cause a picture of severe chronic intestinal dysmotility (eg, obstruction, functional gastrointestinal disorders, drugs, psychosocial issues and malnutrition). It gives management guidelines for patients with an enteric myopathy or neuropathy including the use of enteral and parenteral nutrition.

Idiopathic myenteric ganglionitis as a cause of death in a young male patient with sudden abdominal pain: an autopsy case report

BACKGROUND

Myenteric ganglionitis is a disorder that causes intestinal motor dysfunction. It may be caused due to neoplastic, central nervous system, or systemic infectious disorders. However, some cases are considered to be idiopathic in origin.

CASE PRESENTATION

A 33-year-old man was admitted to the hospital with sudden severe abdominal pain accompanied by watery diarrhea. Computed tomography imaging revealed edema of the entire small intestinal wall without ischemic changes. Detailed examination could not be performed for identifying the cause of abdominal pain because of the patient's worsened general condition, and he died 7 days after onset. The autopsy results confirmed the cause of the patient's severe abdominal pain as an idiopathic myenteric ganglionitis.

CONCLUSION

Some patients with idiopathic myenteric ganglionitis might die without a definitive diagnosis during their lifetime because of the rarity of this disease. When encountering severe intestinal motility abnormalities of unknown cause, physicians should consider idiopathic myenteric ganglionitis when choosing therapy.

Detecting gastrointestinal manifestations in patients with systemic sclerosis using anti-gAChR antibodies

BACKGROUND

Patients with systemic sclerosis (SSc) complicated by gastrointestinal dysmotility are difficult to treat and have high mortality. To clarify the pathogenesis of gastrointestinal manifestations, we aimed to demonstrate the association among the clinical features of SSc, the serological markers, the autoantibodies against nicotinic acetylcholine receptor at autonomic ganglia (gAChR).

METHODS

Fifty patients were enrolled and divided into two groups according to the presence or absence of gastrointestinal manifestations, and the characteristics were analyzed between these two groups. We measured biomarkers and the autoantibodies against two gAChRα3 and β4 subunits to test sera samples. Furthermore, patients were classified based on the presence or absence of anti-gAChR autoantibodies, and their clinical features were compared.

RESULTS

In patients with SSc and gastrointestinal manifestations, digital ulcers were more frequent (p = 0.050) and VEGF expression was significantly higher (p = 0.038). Seven subjects with SSc were seropositive for α3 subunit, whereas one patient was seropositive for β4 subunit. The mean level of anti-gAChRα3 autoantibodies in SSc patients with gastrointestinal manifestations was significantly higher than that in SSc patients without gastrointestinal manifestations (p = 0.001). The group of patients with SSc and gAChR autoantibodies had significantly higher endostatin levels (p = 0.046).

CONCLUSIONS

This study is the first to demonstrate that clinical characteristics of SSc patients with seropositivity for gAChR autoantibodies. Patients with SSc have circulating autoantibodies against gAChR, which may contribute to gastrointestinal manifestations associated with this disease, suggesting that gAChR-mediated autonomic neurotransmission may provide a pathomechanism for gastrointestinal dysmotility in SSc.

Gut epithelial and vascular barrier abnormalities in patients with chronic intestinal pseudo-obstruction

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is a rare condition due to severe impairment of gut motility responsible for recurrent subocclusive episodes. Although neuromuscular-glial-ICC abnormalities represent the main pathogenetic mechanism, the pathophysiology of CIPO remains poorly understood. Intestinal epithelial and vascular endothelial barrier (IEVB) abnormalities can contribute to neuroepithelial changes by allowing passage of harmful substances.

METHODS

To test retrospectively whether IEVB defects occur in patients with CIPO, we measured the jejunal protein expression of the major tight junction (TJ) components. CIPO patients were subdivided according to gut neuromuscular histopathology: apparently normal (AN); with inflammation (INF); or with degenerative alterations (DEG). The presence of occludin/claudin oligomers (index of TJ assembly), the amount of occludin, claudin-4, and zonula occludens-1 (ZO-1), and the expression of vasoactive intestinal polypeptide (VIP) and glial fibrillary acidic protein (GFAP) immunoreactivities were evaluated on jejunal full-thickness biopsies using Western blot.

KEY RESULTS

Oligomers were absent in the 73% of CIPO. Total occludin decreased in CIPO with AN and INF changes. Claudin-4 was upregulated in CIPO with INF and DEG features. ZO-1 and VIP expression decreased selectively in DEG group. GFAP increased in CIPO regardless the histopathological phenotype.

CONCLUSIONS & INFERENCES

The absence of oligomers demonstrated in our study suggests that IEBV is altered in CIPO. The mechanism leading to oligomerization is occludin-dependent in AN and INF, whereas is ZO-1-dependent in DEG. Our study provides support to IEVB abnormalities contributing to CIPO clinical and histopathological features.

Anti-ganglionic AChR antibodies in Japanese patients with motility disorders

BACKGROUND

The existence of several autoantibodies suggests an autoimmune basis for gastrointestinal (GI) dysmotility. Whether GI motility disorders are features of autoimmune autonomic ganglionopathy (AAG) or are related to circulating anti-ganglionic acetylcholine receptor (gAChR) antibodies (Abs) is not known. The aim of this study was to determine the associations between autonomic dysfunction, anti-gAChR Abs, and clinical features in patients with GI motility disorders including achalasia and chronic intestinal pseudo-obstruction (CIPO).

METHODS

First study: retrospective cohort study and laboratory investigation. Samples from 123 patients with seropositive AAG were obtained between 2012 and 2017. Second study: prospective study. Samples from 28 patients with achalasia and 14 patients with CIPO were obtained between 2014 and 2016, and 2013 and 2017, respectively. In the first study, we analyzed clinical profiles of seropositive AAG patients. In the second study, we compared clinical profiles, autonomic symptoms, and results of antibody screening between seropositive, seronegative achalasia, and CIPO groups.

RESULTS

In the first study, we identified 10 patients (8.1%) who presented with achalasia, or gastroparesis, or paralytic ileus. In the second study, we detected anti-gAChR Abs in 21.4% of the achalasia patients, and in 50.0% of the CIPO patients. Although patients with achalasia and CIPO demonstrated widespread autonomic dysfunction, bladder dysfunction was observed in the seropositive patients with CIPO as a prominent clinical characteristic of dysautonomia.

CONCLUSIONS

These results demonstrate a significant prevalence of anti-gAChR antibodies in patients with achalasia and CIPO. Anti-gAChR Abs might mediate autonomic dysfunction, contributing to autoimmune mechanisms underlying these GI motility disorders.

Sera with anti-enteric neuronal antibodies from patients with irritable bowel syndrome promote apoptosis in myenteric neurons of guinea pigs and human SH-Sy5Y cells

BACKGROUND

Sera anti-enteric neuronal antibodies (AENA), neuronal inflammation, and degeneration in myenteric plexus in patients with irritable bowel syndrome (IBS) were reported. Effects of sera AENA in patients with IBS are unclear.

METHODS

Patients with IBS met Rome III criteria were enrolled. Controls included healthy subjects (HS) and patients with slow transit functional constipation, inflammatory bowel disease, chronic intestinal pseudo-obstruction, and autoimmune diseases. Indirect immunofluorescence was used to detect AENA. Anti-enteric neuronal antibodies intensities were termed as "1" = weak fluorescence (mild positive); "2" = moderate fluorescence (moderate positive); "3" = very high fluorescence (intensive positive). Intensities of ≥1 were defined as positive and ≥2 were defined as obvious positive. Cultured myenteric neurons of small intestine from guinea pigs and human SH-Sy5Y cells were incubated with fetal bovine serum (FBS), HS sera, or IBS sera with or without AENA. Indirect immunofluorescence with anti-PGP9.5/DAPI/anti-active caspase-3 or TUNEL, Western blot, and flow cytometry were used to detect apoptosis.

KEY RESULTS

Overall, 293 patients with IBS were enrolled (41.7 ± 11.5 years). AENA-positive and obvious positive rates in IBS were higher than HS (76.8% vs 33%; 43.7% vs 7%; all P < 0.001). Myenteric neurons incubated with AENA moderate or intensive positive IBS sera showed higher rates of anti-active caspase-3 and TUNEL-positive cells than HS or FBS (20% ± 7.3% and 35% ± 13.3% vs 4.3% ± 1.5% and 0.9% ± 0.4%, respectively; 6.2% ± 2.0% and 10.2% ± 4.6% vs 1.3% ± 1.9% and 0.5%±0.5%, respectively; all P < 0.05). Human SH-Sy5Y cells incubated with AENA moderate or intensive positive IBS sera showed increased cleaved caspase-3 and Bax expression and decreased Bcl-2 expression. Flow cytometry showed apoptosis rates of these two groups were higher than that of AENA mild positive, negative, HS, and FBS (7.6%±0.8% and 10.7%±1.3% vs 5.0%±0.8%, 3.8%±0.3%, 3.4%±0.2% and, 2.8%±0.2%, P < 0.05).

CONCLUSIONS AND INFERENCES

The AENA obvious positive rate in patients with IBS was higher than HS, and sera with higher levels of AENA promoted neuronal apoptosis. AENA-mediated neuropathy might exist in a subset of patients with IBS.

Autoimmune autonomic ganglionopathy: an update on diagnosis and treatment

INTRODUCTION

Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder that leads to autonomic failure. The disorder is associated with autoantibodies to the ganglionic nicotinic acetylcholine receptor (gAChR). We subsequently reported that AAG is associated with an overrepresentation of psychiatric symptoms, sensory disturbance, autoimmune diseases, and endocrine disorders. Area covered: The aim of this review was to describe AAG and highlight its pivotal pathophysiological aspects, clinical features, laboratory examinations, and therapeutic options. Expert commentary: AAG is a complex neuroimmunological disease, these days considered as an autonomic failure with extra-autonomic manifestations (and various limited forms). Further comprehension of the pathophysiology of this disease is required, especially the mechanisms of the extra-autonomic manifestations should be elucidated. There is the possibility that the co-presence of antibodies that were directed against the other subunits in both the central and peripheral nAChRs in the serum of the AAG patients. Some patients improve with immunotherapies such as IVIg and/or corticosteroid and/or plasma exchange. ¹²³I-MIBG myocardial scintigraphy may be a useful tool to monitor the therapeutic effects of immunotherapies.

High prevalence and functional effects of serum antineuronal antibodies in patients with gastrointestinal disorders

BACKGROUND

Antineuronal antibodies can be associated with both gastrointestinal (GI) and brain disorders. For example, antibodies against the potassium channel subunit dipeptidyl-peptidase-like protein-6 (DPPX) bind to neurons in the central nervous system (CNS) and myenteric plexus and cause encephalitis, commonly preceded by severe unspecific GI symptoms. We therefore investigated the prevalence of antineuronal antibodies indicative of treatable autoimmune CNS etiologies in GI patients.

METHODS

Serum samples of 107 patients (Crohn's disease n = 42, ulcerative colitis n = 16, irritable bowel syndrome n = 13, others n = 36) and 44 healthy controls were screened for anti-DPPX and further antineuronal antibodies using immunofluorescence on rat brain and intestine and cell-based assays. Functional effects of high-titer reactive sera were assessed in organ bath and Ussing chamber experiments and compared to non-reactive patient sera.

KEY RESULTS

Twenty-one of 107 patients (19.6%) had antibodies against the enteric nervous system, and 22 (20.6%) had anti-CNS antibodies, thus significantly exceeding frequencies in healthy controls (4.5% each). Screening on cell-based assays excluded established antienteric antibodies. Antibody-positive sera were not associated with motility effects in organ bath experiments. However, they induced significant, tetrodotoxin (TTX)-insensitive secretion in Ussing chambers compared to antibody-negative sera.

CONCLUSIONS & INFERENCES

Antineuronal antibodies were significantly more frequent in GI patients and associated with functional effects on bowel secretion. Future studies will determine whether such antibodies indicate patients who might benefit from additional antibody-directed therapies. However, well-characterized encephalitis-related autoantibodies such as against DPPX were not detected, underlining their rarity in routine cohorts.

Intravenous immunoglobulin in drug and device refractory patients with the symptoms of gastroparesis-an open-label study

BACKGROUND

Gastroparesis is a complex clinical entity; many aspects of which remain unknown. Although most patients have idiopathic, diabetic, or postsurgical gastroparesis, many are thought to have measurable neuromuscular abnormalities. Immunotherapy has recently been utilized to treat suspected autoimmune gastrointestinal dysmotility.

METHODS

Fourteen patients with symptoms of gastroparesis (Gp) who were refractory to drug/device were selected from 443 Gp patients from 2013 to 2015 who were treated at the University of Louisville motility center. All patients underwent a structural and psychiatric evaluation along with detailed psychological and behavioral examination to rule out eating disorders. We performed detailed neuromuscular evaluation and all 14 patients received at least 12 weeks of intravenous immunoglobulin (400 mg/kg infusion weekly). Response was defined subjectively (symptomatic improvement) using standardized IDIOM score system.

KEY RESULTS

All 14 patients had serological evidence and/or tissue evidence of immunological abnormality. Post-IVIG therapy, there was a significant improvement in symptoms scores for nausea, vomiting, early satiety, and abdominal pain.

CONCLUSIONS AND INFERENCES

Although limited by the absence of placebo group, the data illustrate the role of autoimmunity and neuromuscular evaluation in patients with gastroparesis and support the utility of a diagnostic trial of immunotherapy in an effort to improve therapeutic outcomes for such patients.

GAD Antibodies as Key Link Between Chronic Intestinal Pseudoobstruction, Autonomic Neuropathy, and Limb Stiffness in a Nondiabetic Patient: A CARE-Compliant Case Report and Review of the Literature

Chronic intestinal pseudoobstruction (CIP) can be a severe burden and even a life-threatening disorder. Typically, several years of uncertainty are passing before diagnosis. We are reporting the case of a young woman with a decade of severe, progressive gastrointestinal dysmotility. Unusually, she had also developed an autonomic neuropathy, and a stiff limb syndrome.In addition to achalasia and CIP the young woman also developed neuropathic symptoms: orthostatic intolerance, urinary retention, a Horner syndrome, and lower limb stiffness. Careful interdisciplinary diagnostics excluded underlying infectious, rheumatoid, metabolic or tumorous diseases.The detection of GAD (glutamic acid decarboxylase) antibodies, however, seemed to link CIP, autonomic neuropathy, and limb stiffness and pointed at an autoimmune origin of our patient's complaints. This was supported by the positive effects of intravenous immunoglobulin. In response to this therapy the body weight had stabilized, orthostatic tolerance had improved, and limb stiffness was reversed.The case suggested that GAD antibodies should be considered in CIP also in nondiabetic patients. This may support earlier diagnosis and immunotherapy.

Increased prevalence of autoimmune diseases in functional gastrointestinal disorders: case-control study of 23471 primary care patients

BACKGROUND

There is increasing evidence that impaired mucosal defence mechanisms are implicated in the pathogenesis of the functional gastrointestinal disorders (FGIDs), allowing inappropriate immune activation.

AIM

To test the hypothesis that an excess of autoimmune disorders among sufferers, using a large primary care database to examine this.

METHODS

Cases were diagnosed with FGIDs - irritable bowel syndrome (IBS), functional dyspepsia (FD), chronic idiopathic constipation (CIC), and multiple FGIDs. Controls were those without FGIDs. Prevalence of autoimmune disorders was compared between cases and controls using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We included 23,471 patients (mean age 51.4 years, 66.1% female). Prevalence of autoimmune disorders was greater among all FGIDs, compared with controls without. In those with FD (OR 1.35; 95% CI 1.12-1.63), CIC (OR 1.75; 95% CI 1.11-2.75), or multiple FGIDs (OR 1.49; 95% CI 1.25-1.77) this was statistically significant after controlling for age and gender. Rheumatological autoimmune disorders were significantly more frequent in those with FD (OR 1.44; 95% CI 1.15-1.80), CIC (OR 1.84; 95% CI 1.08-3.13), or multiple FGIDs (OR 1.53; 95% CI 1.24-1.88), after controlling for age and gender. However, endocrine autoimmune disorders were no more frequent in those with FGIDs, after controlling for age and gender.

CONCLUSIONS

In a large sample of primary care patients, there was a significantly higher prevalence of autoimmune disorders among those with FD, CIC, or multiple FGIDs not explained by differences in age or gender. We were unable to control for concomitant drug use, which may partly explain this association.

Irritable bowel syndrome-type symptoms in female patients with mild systemic lupus erythematosus: frequency, related factors and quality of life

BACKGROUND

Irritable bowel syndrome (IBS) impairs quality of life (HRQOL), as does systemic lupus erythematosus (SLE). Both are more common in women and are associated with fibromyalgia (FM). However, the relationship between IBS and SLE and its impact on HRQOL has not been explored. Therefore, we aimed to study the frequency and features likely to influence the presence of IBS-type symptoms in SLE and their impact on HRQOL.

METHODS

Female patients with SLE were studied. The presence of IBS-type symptoms and bowel habit subtype were established by Rome III criteria and HRQOL was assessed using the SF-36. Fibromyalgia and depression were assessed using the American College of Rheumatology criteria and CES-D scale, respectively.

KEY RESULTS

A total of 105 consecutive patients (43.62 ± 11.34 years old) were included; 48.6% had IBS-type symptoms (SLE+IBS) and were classified as IBS-C: 23.5%, IBS-D: 37.3%, and IBS-M: 39.2%. In addition, 23.8% had FM. SLE+IBS vs Non-IBS SLE patients had higher SLE activity scores (2.55 ± 1.65 vs 1.74 ± 2.19; p = 0.03), were more likely to have FM (33.0% vs 14.8%; p = 0.02) and depression (41.1% vs 25.9%, p = 0.04). Logistic multivariate analysis showed that IBS-type symptoms were associated with FM (OR = 2.85, 95% CI: 1.11-7.43) and depression (OR = 1.07, 95% CI: 1.02-1.13). Finally, SLE+IBS vs Non-IBS SLE patients had lower SF-36 scores (49.65 ± 18.57 vs 62.67 ± 18.14; p = 0.02).

CONCLUSIONS & INFERENCES

IBS-type symptoms are highly prevalent among women with SLE and are associated with FM and depression. SLE+IBS patients had worse HRQOL vs Non-IBS SLE, independently of FM status. We suggest that treating IBS symptoms may improve HRQOL in women with SLE.

Review article: the assessment and management of chronic severe gastrointestinal dysmotility in adults

BACKGROUND

The characterisation and management of chronic severe gastrointestinal (GI) dysmotility are challenging. It may cause intestinal failure requiring home parenteral nutrition (HPN).

AIMS

To review the presentation, aetiology, characterisation, management and outcome of chronic severe GI dysmotility, and to suggest a pragmatic management algorithm.

METHODS

PubMed search was performed up to December 2012 using appropriate search terms, restricted to human articles and reviewed for relevance. Segmental dysmotility, acute ileus, functional syndromes and non-English articles were excluded. Evidence and recommendations were evaluated using the GRADE system.

RESULTS

In total, 721 relevant articles were reviewed. A coherent and definitive picture is hampered by overlapping classification systems using multi-modal characterisation methods, subject to pitfalls and some requiring further validation. The literature is confined to case series with no randomised trials. Fewer than 20% undergo full thickness jejunal biopsy, which are otherwise labelled idiopathic. However, in studies with up to 80% biopsy rates, neuromuscular abnormalities may be found in 90%. Between 14% and 50% will require HPN, comprising 8-14% of all HPN patients, of which 2/3 are primary/idiopathic and 1/3 secondary, with scleroderma being the leading secondary cause. Ten-year  mortality ranges from 13% to 35% and is worst in elderly scleroderma patients. Management includes limited treatments for secondary causes, prokinetics, symptom palliation, psychological support, nutrition, hydration and judicious surgery.

CONCLUSIONS

Severe dysmotility often remains idiopathic. It is rarely possible to alter disease trajectory; consequently, prognosis may be poor. Multi-disciplinary teams in a specialist setting can improve outcomes. Graded recommendations are enumerated and a pragmatic algorithm is suggested.

Immune activation in irritable bowel syndrome: can neuroimmune interactions explain symptoms?

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal (GI) tract characterized by pain or discomfort from the lower abdominal region, which is associated with altered bowel habit. Despite its prevalence, there is currently a lack of effective treatment options for patients. IBS has long been considered as a neurological condition resulting from alterations in the brain gut axis, but immunological alterations are increasingly reported in IBS patients, consistent with the hypothesis that there is a chronic, but low-grade, immune activation. Mediators released by immune cells act to either dampen or amplify the activity of GI nerves. Release of a number of these mediators correlates with symptoms of IBS, highlighting the importance of interactions between the immune and the nervous systems. Investigation of the role of microbiota in these interactions is in its early stages, but may provide many answers regarding the mechanisms underlying activation of the immune system in IBS. Identifying what the key changes in the GI immune system are in IBS and how these changes modulate viscerosensory nervous function is essential for the development of novel therapies for the underlying disorder.

Voltage-gated potassium channel (K(v) 1) autoantibodies in patients with chagasic gut dysmotility and distribution of K(v) 1 channels in human enteric neuromusculature (autoantibodies in GI dysmotility)

BACKGROUND

Autoantibodies directed against specific neuronal antigens are found in a significant number of patients with gastrointestinal neuromuscular diseases (GINMDs) secondary to neoplasia. This study examined the presence of antineuronal antibodies in idiopathic GINMD and GINMD secondary to South American Trypanosomiasis. The GI distribution of voltage-gated potassium channels (VGKCs) was also investigated.

METHODS

Seventy-three patients were included in the study with diagnoses of primary achalasia, enteric dysmotility, chronic intestinal pseudo-obstruction, esophageal or colonic dysmotility secondary to Chagas' disease. Sera were screened for specific antibodies to glutamic acid decarboxylase, voltage-gated calcium channels (VGCCs; P/Q subtype), nicotinic acetylcholine receptors (nAChRs; α3 subtype), and voltage-gated potassium channels (VGKCs, K(V) 1 subtype) using validated immunoprecipitation assays. The distribution of six VGKC subunits (K(V) 1.1-1.6), including those known to be antigenic targets of anti-VGKC antibodies was immunohistochemically investigated in all main human GI tract regions.

KEY RESULTS

Three patients (14%) with chagasic GI dysmotility were found to have positive anti-VGKC antibody titers. No antibodies were detected in patients with idiopathic GINMD. The VGKCs were found in enteric neurons at every level of the gut in unique yet overlapping distributions. The VGKC expression in GI smooth muscle was found to be limited to the esophagus.

CONCLUSIONS & INFERENCES

A small proportion of patients with GI dysfunction secondary to Chagas' disease have antibodies against VGKCs. The presence of these channels in the human enteric nervous system may have pathological relevance to the growing number of GINMDs with which anti-VGKC antibodies have been associated.

Neural autoantibody evaluation in functional gastrointestinal disorders: a population-based case-control study

BACKGROUND

Our goal is to investigate the serum profile of neural autoantibodies in community-based patients with irritable bowel syndrome (IBS) or functional dyspepsia. The pathogenesis of functional gastrointestinal (GI) disorders, including IBS and dyspepsia, are unknown. Theories range from purely psychological to autoimmune alterations in GI tract neuromuscular function.

METHODS

The study subjects, based in Olmsted County, MN, reported symptoms of functional dyspepsia or IBS (n = 69), or were asymptomatic controls (n = 64). Their coded sera were screened for antibodies targeting neuronal, glial, and muscle autoantigens.

RESULTS

The prevalence of neural autoantibodies with functional GI disorders did not differ significantly from controls (17% vs. 13%; P = 0.43). In no case was a neuronal or glial nuclear autoantibody or enteric neuronal autoantibody identified. Neuronal cation channel antibodies were identified in 9% of cases (voltage-gated potassium channel [VGKC] in one dyspepsia case and one IBS case, ganglionic acetylcholine receptor [AChR] in four IBS cases) and in 6% of controls (ganglionic AChR in one, voltage-gated calcium channel [VGCC], N-type, in two and VGKC in one; P = 0.36). The frequency of glutamic acid decarboxylase-65 (GAD65) autoantibodies was similar in cases (10%) and controls (5%; P = 0.23).

CONCLUSIONS

Our data do not support neural autoimmunity as the basis for most IBS or functional dyspepsia cases.

Effect of subcutaneous injection of [Ala]16-aFGF(1-29) on slow transit constipation in mice

AIM: To investigate the potential therapeutical effect of a new acidic fibroblast growth factor (aFGF) fragment - [Ala]¹⁶-aFGF(1-29) against slow transit constipation (STC) in mice and to explore possible mechanisms involved.

METHODS: Sixty ICR mice were divided randomly and equally into test group and control group. A mouse model of STC was established by subcutaneous injection (SC) of morphine [2.5 mg/(kg•d)] for 45 days. The control group was treated with normal saline for the same duration. The fecal character was observed according to the Bristol Stool Form Scale (BSFS), and only mice producing stools conforming to BSFS 1 and 2 were used as STC models. On day 45, six mice were chosen randomly from each group and used to confirm if STC was successfully induced by charcoal propulsion test. The rest mice in each group were divided into test group 1, test group 2, control group 1, and control group 2 (n = 12 each). The test group 1 and control group 1 were treated with [Ala]¹⁶-aFGF(1-29) (300 µg/kg each time, SC) twice per week for 8 weeks, while the test group 2 and control group 2 were treated with the same volume of vehicle. Fecal character was observed in all mice. Eight weeks later, the intestinal propulsion rate (IPR) in mice of each group was measured and the expression of neuron-specific enolase (NSE, a neuronal maker) in the colon was detected by immunohistochemistry and Western blot.

RESULTS: On day 45, the feces in the test group was drier and harder (BSFS 1 and 2) than the control group (BSFS 4 and 5). Both the IPR and expression level of NSE in the test group were significantly lower than those in the control group (63.422% ± 1.791% vs 55.702% ± 1.806%, 1.18800 ± 0.03176 vs 0.88730 ± 0.03554, 0.90520 ± 0.02268 vs 0.71300 ± 0.01654, all P < 0.05 or 0.01). Eight weeks after treatment, the feces in the test group 1 gradually became as smooth and soft (BSFS 4 and 5) as that in the control groups 1 and 2; the IPR and expression level of NSE in colonic tissue in the test group 1 were obviously improved compared to the test group 2 (62.250% ± 5.283% vs 57.190% ± 4.291%, 0.6543 ± 0.0069 vs 0.4193 ± 0.0158, 0.5823 ± 0.019 vs 0.5171 ± 0.0124, all P < 0.05) but showed no significant difference with those in the control groups 1 and 2.

CONCLUSION: Treatment with [Ala]¹⁶-aFGF (1-29) improved constipation symptoms and IPR in STC mice at least partially by protection of the enteric nervous system.

Achalasia, chronic sensory neuropathy, and N-type calcium channel autoantibodies: beneficial response to IVIG

Autoimmune gastrointestinal dysmotility (AGID) can result from paraneoplastic onconeuronal antibodies. Patients may present with regional hypomotility anywhere along the gastrointestinal tract. We report a case of a woman who developed an insidious sensory neuropathy and achalasia. She was found to have a high-titer of N-type voltage gated-calcium channel (VGCC) antibodies. She demonstrated clinical and electrophysiological improvement of her neuropathy, as well as improvement of her swallowing and gait, after treatment with intravenous immunoglobulins.

Intestinal and anorectal motility and functional disorders

Motility and functional disorders of the small intestine, the colon and the anorectum can induce or contribute to symptoms such as diarrhoea, constipation and abdominal pain and may impair nutrient absorption in severe cases. Acute affections of intestinal functions e.g. during gastrointestinal infections usually need no functional diagnostics but resolve spontaneously or with adequate therapy of the underlying disease. By contrast, chronic disturbances of small intestinal, colonic and anorectal motility and/or sensitivity are subject to gastrointestinal function tests. The role of these tests for diagnosis and therapeutic handling of severe intestinal dysmotility/chronic intestinal pseudo-obstruction, severe constipation, diarrhoea, fecal incontinence and irritable bowel syndrome will be discussed in this review that mainly focuses on adults.

New techniques in the tissue diagnosis of gastrointestinal neuromuscular diseases

Gastrointestinal neuromuscular diseases are 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. Common to most of these diseases are symptoms of impaired motor activity which manifest as slowed or obstructed transit with or without evidence of transient or persistent radiological visceral dilatation. A variety of histopathological techniques and allied investigations are being increasingly applied to tissue biopsies from such patients. This review outlines some of the more recent advances in this field, particularly in the most contentious area of small bowel disease manifesting as intestinal pseudo-obstruction.

The role of humoral autoimmunity in gastrointestinal neuromuscular diseases

Dysfunction of the gastrointestinal neuromuscular apparatus (including interstitial cells of Cajal) is presumed to underlie a heterogeneous group of disorders collectively termed gastrointestinal neuromuscular diseases (GINMDs). There is increasing experimental and clinical evidence that some GINMDs are immune-mediated, with cell-mediated dysfunction relatively well studied. Humoral (antibody)-mediated autoimmunity is associated with several well-established acquired neuromuscular diseases and is now implicated in an increasing number of less well-characterised disorders, particularly of the central nervous system. The role of autoimmunity in GINMDs has been less studied. Whilst most work has focused on the presence of antibodies directed to nuclear antigens, particularly in the context of secondary disorders such as paraneoplastic intestinal pseudo-obstruction, the possibility that 'functional' anti-neuronal antibodies directed to membrane-bound ion channels may cause disease (channelopathy) is now also being realised. The evidence for humoral autoimmunity as an etiologic factor in primary (idiopathic) and secondary GINMDs is systematically presented using the original paradigms previously applied to established autoimmune neuromuscular disorders. The presence of anti-enteric neuronal antibodies, although repeatedly demonstrated, still requires the identification of specific neuronal autoantigens and validated evidence of pathogenicity.

Enteric autoantibodies and gut motility disorders

Increasing evidence suggests that a subset of gastrointestinal motility disorders is associated with the presence of circulating antibodies. These antibodies are directed against various molecular targets, the best known being anti-neuronal nuclear antibody (ANNA-1 or anti-Hu) associated with paraneoplastic motility disorders. There is also evidence that the presence of distinct autoantibody profiles is associated with non-paraneoplastic motility disorders. This review focuses on the types of antibodies associated with gastrointestinal motility disorders and the significance of these antibodies. Algorithms are suggested for the work-up and treatment of patients with circulating antibodies associated with gastrointestinal motility disorders.