Autonomic dysfunction in gastrointestinal motility disorders

Pathogenesis and management of diabetic gastroparesis: An updated clinically oriented review

BACKGROUND AND AIMS

Diabetic gastroparesis (DGp) is a common and preventable complication of uncontrolled diabetes mellitus (D.M.) and significantly affects the Quality of Life of patients. Diagnosis and management present as a clinical challenge due to the disease's complexity and limited effective therapeutic options. This review aims to comprehensively outline the pathogenesis, diagnosis, and management of diabetic gastroparesis, evaluating evolving approaches to guide clinicians and provide future recommendations.

METHODS

A literature review was conducted on scholarly databases of PubMed, Google Scholar, Scopus and Web of Science encompassing published articles, gray literature and relevant clinical guidelines. Data were synthesized and analyzed to provide a comprehensive overview of diabetic gastroparesis, focusing on pathogenesis, diagnosis, and management.

RESULTS

The review intricately explores the pathogenesis contributing to diabetic gastroparesis, emphasizing autonomic neuropathy, oxidative stress, inflammation, hormonal dysregulation, microbiota alterations, and gastrointestinal neuropathy. Primary management strategies are underscored, including lifestyle modifications, symptom relief, and glycemic control. The discussion encompasses pharmacological and surgical options, highlighting the importance of a multidisciplinary approach involving various healthcare professionals for comprehensive patient care.

CONCLUSION

This review offers a thorough understanding of pathogenesis, diagnosis, and management of diabetic gastroparesis, underlining evolving approaches for clinicians. A multidisciplinary approach is crucial to address both the physical and mental health aspects of diabetes and its complications.

Involvement of the autonomic nervous system in colonic contractions in conscious Suncus murinus

BACKGROUND

Colonic motility is regulated by various factors along the gut-brain axis; however, detailed mechanisms are unknown. This study aimed to examine the involvement of the autonomic nervous system in colonic motility. Suncus murinus (suncus) is a small laboratory mammal suitable for gastrointestinal motility studies.

METHODS

Colonic motility and concomitant feeding and defecation behaviors in vagotomized and reserpine-administered suncus were recorded simultaneously for 24 h. Furthermore, we performed immunohistochemistry on tyrosine hydroxylase (TH) and in situ hybridization on corticotropin-releasing hormone (CRH) in suncus brain. Additionally, we examined c-Fos expression in the brain using immunohistochemistry in conscious suncus with colorectal distension.

KEY RESULTS

In vagotomized suncus, clustered giant migrating contractions (GMCs), consisting of strong contractions occurring in a short time, were observed, and the percentage of GMCs without defecation increased. The frequency of GMCs in the reserpine-administered suncus increased during a light period (ZT0-4, 4-8) and decreased during a dark period (ZT16-20, 20-24) compared to a vehicle group. Additionally, the percentage of GMCs without defecation in the reserpine-administered suncus increased. Suncus TH-immunopositive neurons were found in the locus coeruleus (LC), as shown in rodents. In contrast, CRH mRNA-expressing cells were not observed in a region assumed to be the Barrington's nucleus (Bar). Furthermore, colorectal distension in conscious suncus induced c-Fos expression in LC TH neurons.

CONCLUSIONS & INFERENCES

Our results suggest that the vagus and sympathetic nerves are not required for induction of GMCs in vivo. However, they are likely to exert a modulatory role in control of GMC frequency in Suncus murinus.

Patterns of Food Selectivity among Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders characterized by food selectivity in a significant portion of the population. The nature of this selectivity remains unclear, with hypotheses suggesting associations with sensory disorders or stereotypical and repetitive patterns of activity and interests. This study aimed to determine the prevalence and nature of food selectivity traits in individuals with ASD compared with the neurotypical population. This study involved 219 participants, with 115 diagnosed with autism and 92 without. Twelve children undergoing diagnosis were excluded from the analyses. The findings revealed that food selectivity traits are more common in individuals with ASD, with differences in preferences mainly involving structure, color, taste, and serving method. Children with ASD had more food selectivity traits than those without, and the intake of certain food characteristics could be altered as they grow. Selectivity occurred for both sensory and stereotypical reasons, but stereotypical features significantly differentiated neurotypical individuals from those with ASD.

Is vitamin B12 deficiency a risk factor for gastroparesis in patients with type 2 diabetes?

BACKGROUND

Diabetic gastroparesis is a severe diabetic complication refers to delayed gastric emptying in the absence of mechanical obstruction of the stomach. Vitamin B12 affects the dynamics of autonomic nervous system and its deficits has been linked to cardiovascular autonomic neuropathy therefore, vitamin B12 deficiency was hypothesized to be implicated in the development of diabetic gastroparesis. This study was conducted to explore the possible association between vitamin B12 deficiency and gastroparesis in patients with type 2 diabetes (T2D).

METHODS

A total of 100 T2D patients with diabetes duration > 10 years and 50 healthy controls matched for age and sex were recruited for this study. T2D patients were divided into 2 groups: patients with gastroparesis and patients without gastroparesis. The diagnosis of gastroparesis was based on Gastroparesis Cardinal Symptom Index (GCSI) Score ≥ 1.9 and ultrasonographic findings including gastric emptying ˂ 35.67% and motility index ˂ 5.1. Anthropometric measurements, plasma glucose, glycosylated hemoglobin (HbA1c), lipids profile, vitamin B12 and transabdominal ultrasonography were assessed.

RESULTS

The frequency of vitamin B12 deficiency in total patients with T2D was 35% (54.5% in patients with gastroparesis vs. 11.1% in patients without gastroparesis, P < 0. 001). Vitamin B12 level was negatively correlated with GCSI Score whereas, it was positively correlated with gastric emptying and motility index. Vitamin B12 deficiency was an independent predictor for gastroparesis in patients with T2D; it predicts gastroparesis at a cut off value of 189.5 pmol/L with 69.1% sensitivity and 64.4% specificity, P = 0.002.

CONCLUSIONS

Beside the known risk factors of diabetic gastroparesis, vitamin B12 deficiency is an independent predictor of diabetic gastroparesis in patients with T2D.

CT-Guided Celiac Ganglion Block for Neurogenic Gastrointestinal Dysmotility

PURPOSE

To determine whether celiac ganglion block can serve as a diagnostic test for dysautonomia as the cause of gastrointestinal dysmotility-related symptoms.

MATERIALS AND METHODS

This was an institutional review board-approved, prospective, single-arm, registered study, from January 2020 to May 2021, and included patients aged 14-85 years with gastrointestinal symptoms of food intolerance, abdominal pain, or angina. Patients with nonneurogenic causes (ie, chronic cholecystitis, peptic ulcer disease, gastroesophageal reflux, and malabsorption syndrome) were excluded. All 15 patients underwent computed tomography-guided celiac ganglion block with 100 mg of liposomal bupivacaine. Patients filled out the dysautonomia-validated questionnaire Composite Autonomic Symptom Score 31 (COMPASS-31) before and after intervention. Differences (before vs after) were compared with the exact permutation method.

RESULTS

Fifteen women (median age, 17 years; range, 14-41 years) were included. Average COMPASS-31 score improved significantly, from baseline 11 (SD ± 2.8) to 4 (SD ± 1.9) (improvement, 7 points ± 2.8; P < .001). All patients reported significant reduction in abdominal angina. Fourteen of the 15 patients (93%) reported complete resolution, and 14 of 15 (93%) reported a significant reduction in non-postprandial abdominal pain (P < .01). Only 1 patient reported no improvement. Eight of those 14 patients (57%) reported complete resolution of abdominal pain. There was a significant improvement in functional scores (vomiting, P = .01; constipation frequency, P = .02; constipation severity, P < .01; and nausea, P < .01). The rate of minor and major adverse events was 13% and 0%, respectively, per the Society of Interventional Radiology adverse event classification.

CONCLUSIONS

Celiac ganglion block is a safe diagnostic tool for confirming dysautonomia as the underlying condition in patients with gastrointestinal dysmotility-related symptoms. It could provide early diagnosis, lead to definitive treatment (ganglionectomy) earlier, or obviate unnecessary surgery.

Modulation of the autonomic nervous system by one session of spinal low-level laser therapy in patients with chronic colonic motility dysfunction

Patients with a defecation disorder may not evoke a normal defecation reflex, or the reflex may be excessive, as a dysfunction of the spinal autonomic nervous system. Treatment with various forms of lumbar and sacral neuromodulation have shown symptom improvement, but potential changes in autonomic functioning are rarely studied. Here we evaluate the effects on autonomic function of a single session of low-level laser therapy (LLLT) on the lumbar and sacral spine in 41 patients with chronic gastrointestinal motor dysfunction. The LLLT protocol used red LED light at a wavelength of 660 nm for 10 min and infrared LED light at a wavelength of 840 nm for 10 min, followed by infrared laser light at a wavelength of 825 nm for 10 min. Effects on the autonomic nervous system were assessed by measuring heart rate variability (HRV) changes. Respiratory Sinus Arrhythmia (RSA) and Root Mean Square of Successive Differences (RMSSD) were used to quantify parasympathetic reactivity; the Baevsky’s Stress Index (SI) reflected sympathetic activity while the ratios SI/RSA and SI/RMSSD were used to show shifts in autonomic dominance. The results indicate that lumbar and sacral neuromodulation using light arrays reduced, whereas stimulation by the laser probes significantly increased parasympathetic activity. The light arrays increased whereas the laser probes significantly decreased sympathetic activity (SI). The entire protocol shifted the autonomic balance toward parasympathetic activity. The comparison of actual vs. sham neuromodulation proved that the change in HRV parameters was due to actual light stimulation and not due to the arrays and probe touching the skin. In conclusion, a single session of LLLT markedly affects autonomic nervous system activity reflected in changes in HRV which is only possible by generating activity in the spinal autonomic nerves. These results warrant a study into the effects of LLLT on restoring autonomic dysfunction in chronic refractory colonic motility disorders.

Enhancing the utility of antroduodenal manometry in pediatric intestinal pseudo-obstruction

BACKGROUND

Antroduodenal manometry (ADM) and histopathology are currently employed to aid the diagnosis of pediatric intestinal pseudo-obstruction (PIPO). Limited data are available on the reliability of ADM analysis and its correlation with histopathology. We aimed to develop a protocol for enhanced analysis of ADM contractile patterns, including a scoring system, and explore whether this provided better correlation with histopathology.

METHODS

Children referred with suspected PIPO between April 2012-December 2019 who underwent both ADM and full-thickness biopsies were included. ADM tracings were analyzed using both standard (conventional ADM) and novel (enhanced ADM) motility parameters. A novel ADM score (GLASS score) was generated based on the enhanced ADM analysis. Conventional and enhanced ADM analyses were then correlated with histopathology.

RESULTS

Forty patients were included. Using conventional clinical criteria, 29 of these were diagnosed with PIPO and the other 11 with non-PIPO diagnoses. Twenty-three of the PIPO patients had abnormal histopathology: 6 myopathy, 4 neuropathy, 3 neuro-myopathy, and 10 non-specific changes. No agreement in diagnosis was found between conventional ADM analysis and histopathology (ϰ = 0.068; p = 0.197), whereas the latter significantly correlated with enhanced ADM analysis (ϰ = 0.191; p = 0.003). The enhanced ADM score was significantly higher in PIPO versus non-PIPO (16.0 vs. 8.0; p < 0.001).

CONCLUSIONS

As opposed to conventional analysis protocols, the newly developed enhanced ADM analysis and associated score is not only able to discriminate between PIPO and non-PIPO patients, but also between distinct histopathological pathologies. Further studies are required to assess the utility of enhanced ADM analysis in larger populations.

Clinical and endoscopic characteristics of acute esophageal necrosis and severe reflux esophagitis

The similarities and differences between acute esophageal necrosis and severe reflux esophagitis have not been elucidated. We compared Los Angeles classification Grade C reflux esophagitis, Grade D reflux esophagitis, and acute esophageal necrosis to consider the similarities and differences between acute esophageal necrosis and severe reflux esophagitis.We retrospectively reviewed records of patients who underwent esophagogastroduodenoscopy at a tertiary referral center from January 2012 to December 2019. Data on patients diagnosed as Grade C reflux, Grade D reflux, or acute esophageal necrosis for the first time were extracted for analysis.A total of 213 patients were enrolled in the study, composed of 130 Grade C reflux, 74 Grade D reflux, and 9 acute esophageal necrosis patients. Compared to Grade C reflux patients, Grade D reflux and acute esophageal necrosis patients were more likely to be transfused (P = .013 and P = .011, respectively), to have duodenal ulcers (P = .025 and P = .049, respectively), and to have psychiatric illnesses (P = .022 and P = .018, respectively). Compared to both Grade C and D reflux, acute esophageal necrosis patients were more likely to present with shock (P = .003 and P < .001, respectively), have type 1 diabetes (P = .030 and P = .004, respectively), and present in winter (P < .001 and P < .001, respectively). Significant step-wise differences (Grade C < Grade D < acute esophageal necrosis) were observed in the need for admission (P < .001 and P = .009), coffee ground emesis (P < .001 and P = .022), and stigmata of hemorrhage on endoscopy (P = .002 and P < .001). Admission (P = .003) and coffee ground emesis (P = .003) independently predicted either Grade D reflux or acute esophageal necrosis over Grade C reflux on multivariate analysis.Shock, type 1 diabetes, and winter may predict acute esophageal necrosis, while the need for admission and coffee ground emesis may predict Grade D reflux or acute esophageal necrosis.

Effects of Provocative Testing on Phase III Migrating Motor Complex in Children

OBJECTIVES

Antroduodenal manometry (ADM) is used to evaluate antral and small intestinal motility, with the presence of phase III migrating motor complexes (MMCs) indicating an intact enteric neuromuscular system. The lack of evidence-based or consensus-driven established norms for MMC in fasting phase and after provocative testing marks a major limitation in the interpretation of ADM studies. We aimed to determine the characteristics of MMC in fasting and post-provocative phase in children.

METHODS

Data from subjects ages <20 years with ADM results evaluated at neuro-gastroenterology and Motility Disorders Center, Cincinnati Children's Hospital Medical Center from January 2018 to March 2019 were analyzed.

RESULTS

Forty-eight ADM tracings that did not demonstrate abnormal patterns were included; the mean age was 10.00 ± 5.72 years and 50% were male. Indications for ADM included: vomiting (27.1%), feeding intolerance (27.1%), abdominal pain (16.6%), nausea (14.6%), and abdominal distension (14.6%). Thirty-seven percent of subjects had enteral access for feeds. During fasting, one-third of all MMC originated in the antrum. Azithromycin-induced MMC occurred in 28% of subjects and two-thirds of these originated in the antrum with antral contractions of significantly higher frequency and amplitude compared to fasting. Octreotide significantly increased frequency, amplitude, and duration of MMC compared to fasting, with 76% originating in the antrum. Both azithromycin and octreotide induced more than one MMC in a third of subjects.

CONCLUSIONS

We describe the characteristics of antral and small intestinal motility during fasting and after provocative testing in children. These values will help standardize our interpretation of pediatric ADM studies.

Optimizing Autonomic Function Analysis via Heart Rate Variability Associated With Motor Activity of the Human Colon

The parameters of heart rate variability (HRV) can non-invasively assess some autonomic activities, and HRV is influenced by many bodily actions. Although parasympathetic activity is the primary driver of colonic propulsive activity, and sympathetic activity a major inhibitor of colonic motility, they are rarely measured and almost play no role in diagnosis of colon motor dysfunction or in standard treatments. Here we set out to optimize HRV analysis of autonomic nervous system changes related to human colon motility. The electrocardiogram and impedance were recorded in synchrony with colonic motor patterns by high-resolution manometry. Respiratory sinus arrhythmia (RSA), root mean square of successive differences of beat-to-beat intervals (RMSSD), the Baevsky Index or Sympathetic Index (SI), and the ratios of SI/RSA and SI/RMSSD were shown to indicate a marked increase in parasympathetic and withdrawal of sympathetic activity during the high-amplitude propagating pressure waves (HAPWs). Strong associations were seen with HAPWs evoked by a meal and rectal bisacodyl indicating a marked increase in parasympathetic and withdrawal of sympathetic activity during the gastrocolic reflex and the defecation reflex. When HAPWs occurred in quick succession, parasympathetic activation (RSA and RMSSD) occurred in a rhythmic fashion. Hence, during propulsive motor patterns, an overall shift in autonomic activity toward increased parasympathetic control was shown to be reflected in HRV. HRV assessment may therefore be valuable in the assessment of autonomic dysfunction related to colonic dysmotility.

Bowel dysfunction after elective spinal surgery: etiology, diagnostics and management based on the medical literature and experience in a university hospital

BACKGROUND

Bowel dysfunction after spinal surgery is often underestimated and if not treated in a timely manner can lead to undesirable surgical interventions or fatal complications. The current medical literature primarily focuses on bowel dysfunction as a result of spinal injury.

OBJECTIVE

The purpose of this review is to explore this topic in evaluating current evidence regarding the causes of acute bowel dysfunction after elective spinal surgery, primarily the thoracolumbar spine. Since available evidence for recommendations of treatment is scarce, an interdisciplinary management approach for treatment of bowel dysfunction following spinal surgery is also formulated.

MATERIAL AND METHODS

An extensive literature search was carried out on PubMed. Keywords that were used in the search included bowel dysfunction, obstruction, postoperative ileus, spinal surgery, spinal fusion, constipation, opioid-induced constipation, colonic pseudo-obstruction, ischemic colitis, immobility-induced bowel changes, epidural anesthesia and diet. Relevant studies were chosen and included in the review. The treatment approach used in the spine center of a university hospital was included.

RESULTS

Current research mainly focuses on investigating the nature and symptomatology of chronic bowel dysfunction after spinal cord injury. Emphasis on the acute phase of bowel dysfunction in patients after elective spinal surgery is lacking. The comorbidities that exacerbate bowel dysfunction postoperatively are well-defined. There has been refinement and expansion of the pharmacological and nonpharmacological treatment that could be implemented. Enough evidence exists to provide sufficient care.

CONCLUSION

Management of acute bowel dysfunction after spinal surgery requires a comprehensive and individualized approach, encompassing comorbidities, behavioral changes, medications and surgery. Close supervision and timely treatment could minimize further complications. Research is required to identify patients who are at a higher risk of developing bowel dysfunction after specific spinal procedures.

The relationship between Gulf War Illness symptom severity and heart rate variability: A pilot study

INTRODUCTION

Gulf War Illness (GWI) is a chronic multisymptom illness affecting 250,000+ veterans of the '90-'91 Gulf War which remains under-explored in terms of its physiological characteristics. We investigated whether subjective GWI symptom severity scores were related to objective measures of autonomic nervous system activity.

METHODS

We estimated activity in the two major branches of the autonomic nervous system (the parasympathetic nervous system [PNS] and the sympathetic nervous system [SNS]) via metrics of heart rate variability in a sample of Veterans who met established criteria for GWI with varying degrees of self-reported symptom severity. We hypothesized that subjective symptom severity scores would be inversely related to PNS activity and positively related to SNS activity.

RESULTS

Significant negative relationships were observed between the root mean square of successive differences of beat-to-beat intervals (a measure of PNS activity) and symptom severity, both overall and across specific GWI symptom categories (sp. fatigue [r = -0.574], gastrointestinal [r = -0.544]). Furthermore, significant positive relationships were observed between the cardiac sympathetic index and symptom severity, both overall and across specific symptom categories (sp. cognitive [r = 0.721], fatigue [r = 0.560], gastrointestinal [r = 0.694], skin [r = 0.686]).

CONCLUSIONS

Metrics of PNS activation revealed a negative relationship with self-reported symptom severity, while metrics of SNS activation revealed a positive relationship. The present results improve our understanding of the physiology of GWI and provide a new window from which to consider this medically unexplained illness.

Epigenetic Alterations Are Associated With Gastric Emptying Disturbances in Diabetes Mellitus

Epigenetic modifications have been implicated to mediate several complications of diabetes mellitus (DM), especially nephropathy and retinopathy. Our aim was to ascertain whether epigenetic alterations in whole blood discriminate among patients with DM with normal, delayed, and rapid gastric emptying (GE).

Electrodiagnostic assessment of the autonomic nervous system: A consensus statement endorsed by the American Autonomic Society, American Academy of Neurology, and the International Federation of Clinical Neurophysiology

Evaluation of disorders of the autonomic nervous system is both an art and a science, calling upon the physician's most astute clinical skills as well as knowledge of autonomic neurology and physiology. Over the last three decades, the development of noninvasive clinical tests that assess the function of autonomic nerves, the validation and standardization of these tests, and the growth of a large body of literature characterizing test results in patients with autonomic disorders have equipped clinical practice further with a valuable set of objective tools to assist diagnosis and prognosis. This review, based on current evidence, outlines an international expert consensus set of recommendations to guide clinical electrodiagnostic autonomic testing. Grading and localization of autonomic deficits incorporates scores from sympathetic cardiovascular adrenergic, parasympathetic cardiovagal, and sudomotor testing, as no single test alone is sufficient to diagnose the degree or distribution of autonomic failure. The composite autonomic severity score (CASS) is a useful score of autonomic failure that is normalized for age and gender. Valid indications for autonomic testing include generalized autonomic failure, regional or selective system syndromes of autonomic impairment, peripheral autonomic neuropathy and ganglionopathy, small fiber neuropathy, orthostatic hypotension, orthostatic intolerance, syncope, neurodegenerative disorders, autonomic hyperactivity, and anhidrosis.

Heart Rate Variability and Gastric Electrical Response to a Cold Pressor Task in Youth with Functional Dyspepsia

BACKGROUND/AIMS

While stress has been implicated in functional dyspepsia (FD), the mechanisms by which stress results in symptoms are not well defined. The aim of the current study was to assess gastric myoelectric and autonomic changes in response to a physical stressor in youth with FD.

METHODS

In a group of healthy controls and pediatric FD subjects, we recorded ECG and EGG signals 30 min before and 60 min after, a cold pressor task (CPT). Gastric EGG and heart rate variability (HRV) parameters were calculated in pre- and post-CPT stages and in short intervals.

RESULTS

The pre-CPT percent tachygastria was higher in FD subjects as compared to controls. However, CPT did not induce any EGG changes in either controls or FD subjects and the two groups did not differ from each other post-CPT. The CPT resulted in an increase in HRV and standard deviation of NN intervals in controls; there was no change in any HRV parameter in FD subjects.

CONCLUSIONS

Acute physical stress does not appear to induce gastric electrical abnormalities in youth with FD. Youth with FD appear to lack the normal flexible autonomic response to a physical stressor.

Utility of the plasma pancreatic polypeptide response to modified sham feeding in diabetic gastroenteropathy and non-ulcer dyspepsia

BACKGROUND

The relationship between cardiovascular and gastrointestinal (ie, plasma pancreatic polypeptide [PP] response to modified sham feeding [MSF]) indices of vagal function is unclear. Hyperglycemia inhibits PP secretion via vagally mediated mechanisms. Our aims were to (a) compare the PP response, (b) its relationship with glycemia, and (c) the relationship between PP response to MSF, gastric emptying (GE) of solids, and symptoms during GE study in healthy controls, patients with diabetic gastroenteropathy (DM), and non-ulcer dyspepsia (NUD).

METHODS

In 24 healthy controls, 40 DM, and 40 NUD patients, we measured plasma PP concentrations during MSF, cardiovagal functions, GE, and symptoms during a GE study.

KEY RESULTS

Baseline PP concentrations were higher in DM than in controls and NUD (P = .01), and in type 2 than in type 1 DM patients (P < .01). The PP increment during MSF was normal (≥20 pg/mL) in 70% of controls, 54% of DM, and 47% of NUD patients. Overall, the PP response and cardiovagal tests were concordant (P = .01). Among patients with a reduced PP increment with MSF, 7/10 of T1DM and 1/7 of T2DM patients had moderate or severe cardiovagal dysfunctions (P < .05). The PP response to MSF was not associated with GE.

CONCLUSIONS & INFERENCES

Up to 30% of healthy controls have a reduced PP increment during MSF, limiting the utility of this test to detect vagal injury. The PP response is more useful when it is normal than abnormal. A reduced PP response is more likely to be associated with cardiovagal dysfunctions in T1DM than in T2DM.

Associations Between Colonic Motor Patterns and Autonomic Nervous System Activity Assessed by High-Resolution Manometry and Concurrent Heart Rate Variability

Abnormal colonic motility may be associated with dysfunction of the autonomic nervous system (ANS). Our aim was to evaluate if associations between colonic motor patterns and autonomic neural activity could be demonstrated by assessing changes in heart rate variability (HRV) in healthy volunteers. A total of 145 colonic motor patterns were assessed in 11 healthy volunteers by High-Resolution Colonic Manometry (HRCM) using an 84-channel water-perfused catheter. Motor patterns were evoked by balloon distention, a meal and luminal bisacodyl. The electrocardiogram (ECG) and cardiac impedance were assessed during colonic manometry. Respiratory sinus arrhythmia (RSA) and root mean square of successive differences of beat-to-beat intervals (RMSSD) served as measures of parasympathetic reactivity while the Baevsky's Stress Index (SI) and the pre-ejection period (PEP) were used as measures of sympathetic reactivity. Taking all motor patterns into account, our data show that colonic motor patterns are accompanied by increased parasympathetic activity and decreased sympathetic activity that may occur without eliciting a significant change in heart rate. Motor Complexes (more than one motor pattern occurring in close proximity), High-Amplitude Propagating Pressure Waves followed by Simultaneous Pressure Waves (HAPW-SPWs) and HAPWs without SPWs are all associated with an increase in RSA and a decrease in SI. Hence RSA and SI may best reflect autonomic activity in the colon during these motor patterns as compared to RMSSD and PEP. SI and PEP do not measure identical sympathetic reactivity. The SPW, which is a very low amplitude pressure wave, did not significantly change the autonomic measures employed here. In conclusion, colonic motor patterns are associated with activity in the ANS which is reflected in autonomic measures of heart rate variability. These autonomic measures may serve as proxies for autonomic neural dysfunction in patients with colonic dysmotility.

Diabetic Gastroparesis

This review covers the epidemiology, pathophysiology, clinical features, diagnosis, and management of diabetic gastroparesis, and more broadly diabetic gastroenteropathy, which encompasses all the gastrointestinal manifestations of diabetes mellitus. Up to 50% of patients with type 1 and type 2 DM and suboptimal glycemic control have delayed gastric emptying (GE), which can be documented with scintigraphy, 13C breath tests, or a wireless motility capsule; the remainder have normal or rapid GE. Many patients with delayed GE are asymptomatic; others have dyspepsia (i.e., mild to moderate indigestion, with or without a mild delay in GE) or gastroparesis, which is a syndrome characterized by moderate to severe upper gastrointestinal symptoms and delayed GE that suggest, but are not accompanied by, gastric outlet obstruction. Gastroparesis can markedly impair quality of life, and up to 50% of patients have significant anxiety and/or depression. Often the distinction between dyspepsia and gastroparesis is based on clinical judgement rather than established criteria. Hyperglycemia, autonomic neuropathy, and enteric neuromuscular inflammation and injury are implicated in the pathogenesis of delayed GE. Alternatively, there are limited data to suggest that delayed GE may affect glycemic control. The management of diabetic gastroparesis is guided by the severity of symptoms, the magnitude of delayed GE, and the nutritional status. Initial options include dietary modifications, supplemental oral nutrition, and antiemetic and prokinetic medications. Patients with more severe symptoms may require a venting gastrostomy or jejunostomy and/or gastric electrical stimulation. Promising newer therapeutic approaches include ghrelin receptor agonists and selective 5-hydroxytryptamine receptor agonists.

Clinical Characteristics and Associated Systemic Diseases in Patients With Esophageal "Absent Contractility"-A Clinical Algorithm

GOALS

This study was carried out to assess the clinical characteristics and associated systemic diseases seen in patients diagnosed with absent contractility as per the Chicago Classification version 3.0, allowing us to propose a diagnostic algorithm for their etiologic testing.

BACKGROUND

The Chicago Classification version 3.0 has redefined major and minor esophageal motility disorders using high-resolution esophageal manometry. There is a dearth of publications based on research on absent contractility, which historically has been associated with myopathic processes such as systemic sclerosis (SSc).

STUDY

We conducted a retrospective, multicenter study. Data of patients diagnosed with absent contractility were pooled from Cleveland Clinic, Cleveland, OH (January 2006 to July 2016) and Metrohealth Medical Center, Cleveland, OH (July 2014 to July 2016) and included: age, gender, associated medical conditions, surgical history, medications, and specific antibody testing.

RESULTS

A total of 207 patients, including 57 male individuals and 150 female individuals, with mean age of 56.1 and 60.0 years, respectively, were included. Disease distribution was as follows: SSc (diffuse or limited cutaneous) 132, overlap syndromes 7, systemic lupus erythematosus17, Sjögren syndrome 4, polymyositis 3, and dermatomyositis 3. Various other etiologies including gastroesophageal reflux disease, postradiation esophagitis, neuromuscular disorders, and surgical complications were seen in the remaining cohort.

CONCLUSIONS

Most practitioners use the term "absent contractility" interchangeably with "scleroderma esophagus"; however, only 63% of patients with absent contractility had SSc. Overall, 20% had another systemic autoimmune rheumatologic disease and 16% had a nonrheumatologic etiology for absent contractility. Therefore, alternate diagnosis must be sought in these patients. We propose an algorithm for their etiologic evaluation.

Clinical factors associated with the occurrence of nausea and vomiting in type 2 diabetes patients treated with glucagon-like peptide-1 receptor agonists

AIMS/INTRODUCTION

Research has proved a correlation between glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and gastrointestinal adverse events. Predominantly, nausea and vomiting are frequent gastrointestinal adverse events that lead to the discontinuation of GLP-1 RAs treatment. The present study aims to investigate clinical factors related to nausea and vomiting, considering diabetic complications and agents affecting the gastrointestinal tract, such as proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs), in patients with type 2 diabetes treated with GLP-1 RAs.

MATERIALS AND METHODS

This retrospective study included Japanese patients with type 2 diabetes who started receiving GLP-1 RAs therapy. We assessed nausea and vomiting up to 48 weeks after treatment with GLP-1 RAs and used Fine-Gray's proportional hazards model to investigate clinical factors related to nausea and vomiting.

RESULTS

A total of 130 patients were included in this study. Patients with PPIs or H2RAs showed a higher incidence of nausea and vomiting at 48 weeks than those without PPIs or H2RAs. The multivariate analysis revealed that female sex, retinopathy and treatment with PPIs or H2RAs were statistically significant risk factors for nausea and vomiting. Analysis of patients without PPIs or H2RAs showed that female sex and retinopathy were also statistically significant risk factors.

CONCLUSIONS

The present study showed a significant correlation of PPIs or H2RAs, female sex, and diabetic retinopathy with nausea and vomiting in patients with type 2 diabetes treated with GLP-1 RAs. Hence, the occurrence of nausea and vomiting in patients with these factors warrants attention.

Postural Tachycardia Syndrome (POTS) and the GI Tract: A Primer for the Gastroenterologist

Postural tachycardia syndrome (POTS) is one of the most common causes of orthostatic intolerance and is being increasingly recognized in clinical practice. Gastrointestinal (GI) symptoms are reported commonly in patients with POTS and pose a considerable management challenge, making it imperative that gastroenterologists be aware of this condition and its GI comorbidities. Although the evidence presented herein does not prove causation, it does support an association between GI symptoms, GI dysmotility, and POTS. At present, the evaluation and treatment of GI symptoms in patients with POTS remains largely empirical. General measures to treat POTS may lead to improvement in both GI and non-GI symptoms. GI symptoms refractory to these measures should prompt further diagnostic evaluation of gastrointestinal dysmotility and appropriate dietary and pharmacologic management. This review focuses its attention on the involvement of the GI tract in POTS including a discussion of GI symptoms and conditions associated with POTS, followed by an analysis of abnormalities in gut physiology described in POTS, and concluding with an overview of management and suggestions for research directions.

A single-center audit of the indications and clinical impact of prolonged ambulatory small intestinal manometry

BACKGROUND

Small bowel manometry is a diagnostic test available only in a few specialized referral centers. Its exact place in the management of refractory symptoms is controversial.

METHODS

The records of all patients who underwent 24-hour ambulatory duodenojejunal manometry over a 6-year period were retrospectively reviewed. We studied the clinical indications for small bowel manometry, and reviewed the impact of manometric findings on the clinical outcome. One hundred and forty-six studies were performed in 137 patients (46M, 91F) with a mean age of 44.9 ± 15.7 years. Mean follow-up duration was 15.1 ± 22.6 months. Appropriate endoscopic, radiological and gastric scintigraphy studies were performed in all patients prior to small bowel manometry. Criteria for abnormal motor activity were based on Bharucha's classification.

KEY RESULTS

The indications for small bowel manometry were chronic abdominal pain (n = 43), slow-transit constipation (n = 17), refractory gastroparesis (n = 16), chronic diarrhea (n = 7), recurrent episodes of subocclusion (n = 16), postsurgical evaluation (n = 36), suspicion of gut involvement in systemic disease (n = 9), and unexplained nausea (n = 2). The most common finding was a normal 24-hour ambulatory small bowel manometry (n = 113). Thirty-three studies yielded abnormal findings which included extrinsic neuropathy (n = 6), intrinsic neuropathy (n = 18), intestinal myopathy (n = 2), and subocclusion (n = 7). Ambulatory small bowel manometry excluded a generalized motility disorder in 77% and had a significant impact on the subsequent clinical course in 23%.

CONCLUSIONS & INFERENCES

Ambulatory small bowel manometry is a useful and safe diagnostic tool to complement traditional investigative modalities in patients with severe unexplained abdominal symptoms.

The Association Between Fasting C-peptide and Gastrointestinal Symptoms of Gastroparesis in Type 2 Diabetic Patients

Background/Aims

The relationship between C-peptide levels and gastrointestinal (GI) symptoms in type 2 diabetic patients is not clear. The purpose of this study is to examine the association between fasting C-peptide and GI symptoms of gastroparesis in type 2 diabetic patients.

Methods

We recruited 333 type 2 diabetic patients into the present study. All patients filled out questionnaires of gastroparesis cardinal symptom index (GCSI) to evaluate GI symptoms. Hospital anxiety and depression scale were adopted to define anxiety and depression. Patients with GCSI scores ≥ 1.9 were regarded as having symptoms of gastroparesis.

Results

In our study, 71 (21.3%) type 2 diabetic patients had GCSI scores ≥ 1.9. In comparison to patients with scores < 1.9, those with scores ≥ 1.9 had significantly lower fasting c-peptide levels (1.49 ng/mL vs 1.94 ng/mL, P < 0.001), higher prevalence of depression (40.9% vs 18.3%, P < 0.001) and anxiety (28.2% vs 13.0%, P = 0.002). Multivariate logistic regression revealed that fasting C-peptide was still significantly associated with symptoms of gastroparesis (odds ratio, 0.67; 95% confidence intervals, 0.48–0.94; P = 0.021), even after adjustments for age, sex, body mass index, HbA1c, current smoking and drinking status, anxiety, and depression. Furthermore, linear regressions showed that fasting C-peptide was independently and negatively related to GCSI scores (standardized regression coefficient, −0.29; P < 0.001) in patients with at least one GI symptom.

Conclusion

GI symptoms of diabetic gastroparesis affect approximately 20% of type 2 diabetes patients and are associated with lower fasting C-peptide levels independent of depression and anxiety status.

The serotonin receptor mediates changes in autonomic neurotransmission and gastrointestinal transit induced by heat-killed Lactobacillus brevis SBC8803

Lactobacilli exhibit several health benefits in mammals, including humans. Our previous reports established that heat-killed Lactobacillus brevis SBC8803 (SBC8803) increased both efferent gastric vagal nerve activity and afferent intestinal vagal nerve activity in rats. We speculated that this strain could be useful for the treatment of gastrointestinal (GI) disorders. In this study, we examined the effects of SBC8803 on peristalsis and the activity of the efferent celiac vagal nerve innervating the intestine in rats. First, we examined the effects of intraduodenal (ID) administration of SBC8803 on efferent celiac vagal nerve activity (efferent CVNA) in urethane-anesthetised rats using electrophysiological studies. The effects of intravenous injection of the serotonin 5-HT3 receptor antagonist granisetron on changes in efferent CVNA due to ID administration of SBC8803 were also investigated. Finally, the effects of oral gavage of SBC8803 on GI transit were analysed using the charcoal propulsion method in conscious rats treated with or without granisetron. ID administration of SBC8803 increased efferent CVNA. Pretreatment with granisetron eliminated SBC8803-dependent changes in efferent CVNA. Furthermore, oral gavage of SBC8803 significantly accelerated GI transit, while pretreatment with granisetron inhibited GI transit. Our findings suggested that SBC8803 increased efferent CVNA and GI transit of charcoal meal via 5-HT3 receptors. Moreover, SBC8803 enhanced the activity of efferent vagal nerve innervating the intestine and promoted peristalsis via 5-HT3 receptors.

Delayed Gastric Emptying Is Associated With Early and Long-term Hyperglycemia in Type 1 Diabetes Mellitus

BACKGROUND & AIMS

After the Diabetes Control and Complications Trial (DCCT), the Epidemiology of Diabetes Interventions and Complications (EDIC) study continued to show persistent benefit of prior intensive therapy on neuropathy, retinopathy, and nephropathy in type 1 diabetes mellitus (DM). The relationship between control of glycemia and gastric emptying (GE) is unclear.

METHODS

We assessed GE with a (13)C-spirulina breath test and symptoms in 78 participants with type 1 diabetes at year 20 of EDIC. The relationship between delayed GE and glycated hemoglobin (HbA1c), complications of DM, and gastrointestinal symptoms were evaluated.

RESULTS

GE was normal (37 participants; 50%), delayed (35 participants; 47%), or rapid (2 participants; 3%). The latest mean HbA1c was 7.7%. In univariate analyses, delayed GE was associated with greater DCCT baseline HbA1c and duration of DM before DCCT (P ≤ .04), greater mean HbA1c over an average of 27 years of follow-up evaluation (during DCCT-EDIC, P = .01), lower R-R variability during deep breathing (P = .03) and severe nephropathy (P = .05), and a greater composite upper gastrointestinal symptom score (P < .05). In multivariate models, retinopathy was the only complication of DM associated with delayed GE. Separately, DCCT baseline HbA1c (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1-2.3) and duration of DM (OR, 1.2; 95% CI, 1.01-1.3) before DCCT entry and mean HbA1c during DCCT-EDIC (OR, 2.2; 95% CI, 1.04-4.5) were associated independently with delayed GE.

CONCLUSIONS

In the DCCT/EDIC study, delayed GE was remarkably common and associated with gastrointestinal symptoms and with measures of early and long-term hyperglycemia. ClinicalTrials.gov numbers NCT00360815 and NCT00360893.

Relationship between glycemic control and gastric emptying in poorly controlled type 2 diabetes

BACKGROUND & AIMS

Acute hyperglycemia delays gastric emptying in patients with diabetes. However, it is not clear whether improved control of glycemia affects gastric emptying in these patients. We investigated whether overnight and short-term (6 mo) improvements in control of glycemia affect gastric emptying.

METHODS

We studied 30 patients with poorly controlled type 2 diabetes (level of glycosylated hemoglobin, >9%). We measured gastric emptying using the [(13)C]-Spirulina platensis breath test on the patients' first visit (visit 1), after overnight administration of insulin or saline, 1 week later (visit 2), and 6 months after intensive therapy for diabetes. We also measured fasting and postprandial plasma levels of C-peptide, glucagon-like peptide 1, and amylin, as well as autonomic functions.

RESULTS

At visit 1, gastric emptying was normal in 10 patients, delayed in 14, and accelerated in 6; 6 patients had gastrointestinal symptoms; vagal dysfunction was associated with delayed gastric emptying (P < .05). Higher fasting blood levels of glucose were associated with shorter half-times of gastric emptying (thalf) at visits 1 (r = -0.46; P = .01) and 2 (r = -0.43; P = .02). Although blood levels of glucose were lower after administration of insulin (132 ± 7 mg/dL) than saline (211 ± 15 mg/dL; P = .0002), gastric emptying thalf was not lower after administration of insulin, compared with saline. After 6 months of intensive therapy, levels of glycosylated hemoglobin decreased from 10.6% ± 0.3% to 9% ± 0.4% (P = .0003), but gastric emptying thalf did not change (92 ± 8 min before, 92 ± 7 min after). Gastric emptying did not correlate with plasma levels of glucagon-like peptide 1 and amylin.

CONCLUSIONS

Two-thirds of patients with poorly controlled type 2 diabetes have mostly asymptomatic yet abnormal gastric emptying. Higher fasting blood levels of glucose are associated with faster gastric emptying. Overnight and sustained (6 mo) improvements in glycemic control do not affect gastric emptying.

Epidemiology and natural history of gastroparesis

Gastroparesis is characterized by delayed gastric emptying and symptoms thereof in the absence of gastric outlet obstruction. Most studies on the epidemiology of gastroparesis have been conducted in selected case series rather than in the population at large. In the only community-based study of gastroparesis in diabetes mellitus (DM), the average cumulative incidence of symptoms and delayed gastric emptying over 10 years was higher in type 1 DM (5%) than in type 2 DM (1%) and controls (1%). In the United States, the incidence of hospitalizations related to gastroparesis increased substantially between 1995 and 2004, and particularly after 2000.

Disturbances of gastrointestinal transit and autonomic functions in postural orthostatic tachycardia syndrome

BACKGROUND

Gastrointestinal symptoms are common in the postural orthostatic tachycardia syndrome (POTS). However, few studies have evaluated gastrointestinal transit in POTS. Our primary objectives were to evaluate gastrointestinal emptying and the relationship with autonomic dysfunctions in POTS.

METHODS

We reviewed the complete medical records of all patients aged 18 years and older with POTS diagnosed by a standardized autonomic reflex screen who also had a scintigraphic assessment of gastrointestinal transit at Mayo Clinic Rochester between 1998 and 2012. Associations between specific gastric emptying and autonomic (i.e., cardiovagal, adrenergic, and sudomotor) disturbances were evaluated.

KEY RESULTS

Among 163 patients (140 women, mean [± SEM] age 30 [± 1] years), 55 (34%) had normal, 30 (18%) had delayed, and 78 (48%) had rapid gastric emptying. Fifty-eight patients (36%) had clinical features of physical deconditioning, which was associated (p = 0.02) with rapid gastric emptying. Associations with delayed gastric emptying included vomiting, which was more common (p < 0.003), and anxiety or depression, which was less common (p = 0.02). The tilt-associated increase in heart rate and reduction in systolic BP at 1 min was associated (p < 0.05), being greater in patients with delayed gastric emptying.

CONCLUSIONS & INFERENCES

Two-thirds of patients with POTS and GI symptoms had abnormal, most frequently rapid gastric emptying. Except for more severe adrenergic impairment in patients with delayed gastric emptying, the pattern of autonomic dysfunction did not discriminate among gastric emptying groups. Further studies are necessary to ascertain whether extravascular volume depletion and/or deconditioning contribute to POTS in patients with gastrointestinal symptoms.

Intestinal manometry: who needs it?

The use of manometry, i.e. the recording of pressures within hollow viscera, after being successfully applied to the study of esophageal and anorectal motor dysfunctions, has also been used to investigate physiological and pathological conditions of the small bowel. By means of this technique, it has been possible to understand better the normal motor functions of the small intestine, and their relationship and variations following physiologic events, such as food ingestion. Moreover, intestinal manometry has proved useful to document motor abnormalities of the small bowel, although recognition of altered patterns specific for a determinate pathologic condition is still unavailable. However, this technique often permits the detection of abnormal gut motility in patients with abdominal symptoms such as unexplained vomiting and diarrhea, and it is sometimes also useful to address therapeutic targeting.

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.

Technique of functional and motility test: how to perform antroduodenal manometry

Antroduodenal manometry is one of the methods to evaluate stomach and duodenal motility. This test is a valuable diagnostic tool for gastrointestinal motility disorders especially small intestinal pseudo-obstruction which is difficult to make definite diagnosis by clinical manifestations or radiologic findings. Manometric findings that have no evidence of mechanical obstruction and suggestive of pseudo-obstruction with neuropathy or myopathy can avoid unnecessary surgery and the treatment can be directly targeted. Moreover, among patients who have clinically suspected small intestinal pseudo-obstruction but with normal manometric findings, the alternative diagnosis including psychiatric disorder or other organic disease should be considered. The application of this test to the patients with functional gastrointestinal symptoms especially to find the association of motor abnormalities to the symptom has less impressive yield. Antroduodenal manometry is now readily available only in some tertiary care centers. The aim of this review is to describe the antroduodenal manometry technique, interpretation and clinical utility.

Gastric emptying in postural tachycardia syndrome: a preliminary report

PURPOSE

Autonomic neuropathy is widely recognized to be associated with upper gastrointestinal symptoms and abnormal (i.e., rapid or slow) gastric emptying. While patients with postural orthostatic tachycardia syndrome (POTS) may also have gastrointestinal symptoms, our understanding of gastric-emptying disturbances in POTS is very limited. The objectives of this study were to evaluate the relationship between gastric-emptying disturbances and gastrointestinal symptoms in patients with POTS.

METHODS

We retrospectively reviewed the medical records of 22 well-characterized patients with POTS and upper gastrointestinal symptoms in whom autonomic (i.e., postganglionic sudomotor, cardiovagal, and adrenergic) functions and gastric emptying were evaluated using standardized techniques and scintigraphy, respectively. Medical records were reviewed retrospectively to assess clinical features, gastric emptying, and autonomic functions.

RESULTS

Over 70 % of patients had nausea and/or vomiting, which was the most common GI symptom; other common symptoms were abdominal pain (59 %), bloating (55 %), and postprandial fullness/early satiety (46 %). Over one-third of patients had abnormal [i.e., rapid (27 %) or delayed (9 %)] gastric emptying. Gastric-emptying disturbances were not significantly associated with GI symptoms, autonomic symptoms or autonomic dysfunction.

CONCLUSIONS

Over one-third of patients with POTS and gastrointestinal symptoms have abnormal, more frequently rapid than delayed gastric emptying. These findings need to be confirmed in a larger cohort of patients.

A randomised controlled study of the effect of cholinesterase inhibition on colon function in patients with diabetes mellitus and constipation

OBJECTIVES

Chronic constipation in diabetes mellitus is associated with colonic motor dysfunction and is managed with laxatives. Cholinesterase inhibitors increase colonic motility. This study evaluated the effects of a cholinesterase inhibitor on gastrointestinal and colonic transit and bowel function in diabetic patients with constipation.

DESIGN

After a 9-day baseline period, 30 patients (mean ± SEM age 50 ± 2 years) with diabetes mellitus (18 type 1, 12 type 2) and chronic constipation without defaecatory disorder were randomised to oral placebo or pyridostigmine, starting with 60 mg three times a day, increasing by 60 mg every third day up to the maximum tolerated dose or 120 mg three times a day; this dose was maintained for 7 days. Gastrointestinal and colonic transit (assessed by scintigraphy) and bowel function were evaluated at baseline and the final 3 and 7 days of treatment, respectively. Treatment effects were compared using analysis of covariance, with gender, body mass index and baseline colonic transit as covariates.

RESULTS

19 patients (63%) had moderate or severe autonomic dysfunction; 16 (53%) had diabetic retinopathy. 14 of 16 patients randomised to pyridostigmine tolerated 360 mg daily; two patients took 180 mg daily. Compared with placebo (mean ± SEM 1.98 ± 0.17 (baseline), 1.84 ± 0.16 (treatment)), pyridostigmine accelerated (1.96 ± 0.18 (baseline), 2.45 ± 0.2 units (treatment), p<0.01) overall colonic transit at 24 h, but not gastric emptying or small-intestinal transit. Treatment effects on stool frequency, consistency and ease of passage were significant (p ≤ 0.04). Cholinergic side effects were somewhat more common with pyridostigmine (p=0.14) than with placebo.

CONCLUSIONS

Cholinesterase inhibition with oral pyridostigmine accelerates colonic transit and improves bowel function in diabetic patients with chronic constipation.

[Neuropathy in the gut. Gastrointestinal motility disorders in patients with diabetes mellitus]

The extent and severity of motility disorders remains heterogeneous in the different parts of the gut, and in most cases failures in gut motility do not correspond with the severity of the symptoms. If diarrhea or fecal incontinence is the leading symptom, or the blood glucose level varies frequently and considerably despite the treatment efforts, the motility of the stomach and bowels is seriously disturbed. The clinical aspects, detailed pathogenesis, diagnostic approach and treatment modalities of gastrointestinal motility disorders in diabetes mellitus are reviewed to help and improve the everyday medical practice.

A peripheral adrenoceptor-mediated sympathetic mechanism can transform stress-induced analgesia into hyperalgesia

BACKGROUND

Stress has paradoxical effects on pain, causing stress-induced analgesia but also exacerbating pain via poorly understood mechanisms. Adrenergic neurotransmission is integral in pathways that regulate the response to both pain and stress. Hyperalgesia is often associated with enhanced adrenergic sensitivity of primary afferents, but sympathetic nervous system outflow has not been demonstrated to exacerbate pain perception after stress.

METHODS

Rats or C57/BL6 wild-type mice treated with α-2 receptor antagonists or α-2A receptor knockout mice were exposed to ultrasonic noise stress or footshock stress and subsequently tested for hotplate paw withdrawal latencies. The sensory sensitivity of α-2A knockout mice to electrical and chemical stimuli was tested neurophysiologically and behaviorally. The effects of sympatholytic treatments were investigated.

RESULTS

Noise and footshock stressors induced thermal hyperalgesia in rats pretreated systemically with α-2 antagonists. Wild-type mice pretreated with α-2 antagonists and α-2A knockout mice also exhibited thermal hyperalgesia induced by noise stress. Local spinal or intraplantar injection of an α-2 antagonist counteracted stress-induced analgesia without causing hyperalgesia. The α-2A knockout mice had decreased thresholds for peripheral sensitization with sulprostone and for windup of the dorsal horn neuronal response to repetitive electrical stimuli. Stress-induced hyperalgesia was abolished and the sensitization was attenuated by sympathectomy or systemic administration of an α-1-adrenergic antagonist.

CONCLUSIONS

Sympathetic postganglionic nerves can enhance pain sensation via a peripheral α-1-adrenoceptor mechanism when sympathetic outflow is disinhibited. The net effect of stress on pain sensation reflects a balance between descending spinal inhibition and sympathetic outflow that can shift toward pain facilitation when central and peripheral α-2-adrenoceptor inhibitory mechanisms are attenuated.

Impaired gastric response to modified sham feeding in patients with postprandial distress syndrome

BACKGROUND

Impaired vagal function has been reported to be important in some patients with functional dyspepsia (FD). However, the pathophysiologic mechanisms influencing the cephalic phase of vagal activity in FD are incompletely understood. The aim of this study was to investigate the gastric response to modified sham feeding (MSF) on ultrasound and cardiovascular autonomic function in FD patients.

METHODS

Nineteen patients with postprandial distress syndrome (PDS, 11 men and eight women; mean age: 48.2 years) and 26 healthy subjects (HS, 13 men and 13 women; mean age: 45.0 years) were studied prospectively. Firstly, cardiovascular autonomic function was assessed by spectral analysis of RR interval variability. Antral contraction was then evaluated by ultrasonography after MSF was performed to stimulate the cephalic phase of vagal activity.

KEY RESULTS

Spectral analysis of RR interval variability showed that the high-frequency component was significantly smaller in the patients than in the HS (P<0.01). The frequency of antral contraction in response to MSF over 15 min was also significantly lower in the PDS patients than in the HS. The 15-min integrated antral contractile response (area under the contraction vs time curve) was significantly smaller in the PDS patients than in the HS (P<0.01). Univariate analysis revealed a modest correlation between the high-frequency component of RR interval variability and the area under the contraction vs time curve (n=46, r=0.49, P<0.01).

CONCLUSIONS & INFERENCES

Autonomic abnormalities affecting the cephalic phase of vagal activity may be important in the pathogenesis of FD.

Relationships between Irritable Bowel Syndrome Pain, Skin Temperature Indices of Autonomic Dysregulation, and Sensitivity to Thermal Cutaneous Stimulation

This study evaluated relationships between irritable bowel syndrome (IBS) pain, sympathetic dysregulation, and thermal pain sensitivity. Eight female patients with diarrhea-predominant IBS and ten healthy female controls were tested for sensitivity to thermal stimulation of the left palm. A new method of response-dependent thermal stimulation was used to maintain pain intensity at a predetermined level (35%) by adjusting thermal stimulus intensity as a function of pain ratings. Clinical pain levels were assessed prior to each testing session. Skin temperatures were recorded before and after pain sensitivity testing. The temperature of palmar skin dropped (1.5°C) when the corresponding location on the opposite hand of control subjects was subjected to prolonged thermal stimulation, but this response was absent for IBS pain patients. The patients also required significantly lower stimulus temperatures than controls to maintain a 35% pain rating. Baseline skin temperatures of patients were significantly correlated with thermode temperatures required to maintain 35% pain ratings. IBS pain intensity was not significantly correlated with skin temperature or pain sensitivity. The method of response-dependent stimulation revealed thermal hyperalgesia and increased sympathetic tone for chronic pain patients, relative to controls. Similarly, a significant correlation between resting skin temperatures and thermal pain sensitivity for IBS but not control subjects indicates that tonic sympathetic activation and a thermal hyperalgesia were generated by the chronic presence of visceral pain. However, lack of a significant relationship between sympathetic tone and ratings of IBS pain casts doubt on propositions that the magnitude of IBS pain is determined by psychological stress.

Diabetes mellitus and gastric emptying: questions and issues in clinical practice

It is long known that both type 1 and type 2 diabetes can be associated with changes in gastric emptying; a number of publications have linked diabetes to delayed gastric emptying of variable severity and often with poor relationship to gastrointestinal symptomatology. In contrast, more recent studies have reported accelerated gastric emptying when adjusted for glucose concentration in patients with diabetes, indicating a reciprocal relationship between gastric emptying and ambient glucose concentrations. This review proposes that gastroparesis or gastroparesis diabeticorum, a severe condition characterized by a significant impairment of gastric emptying accompanied by severe nausea, vomiting, and malnutrition, is often overdiagnosed and not well contrasted with delays in gastric emptying. The article offers a clinically relevant definition of gastroparesis that should help differentiate this rare condition from (often asymptomatic) delays in gastric emptying. The fact that delayed gastric emptying can also be observed in non-diabetic individuals under experimental conditions in which hyperglycaemia is artificially induced suggests that a delay in gastric emptying rate when blood glucose concentrations are high is actually an appropriate physiological response to hyperglycaemia, slowing further increases in blood glucose. The article discusses the strengths and weaknesses of various methodologies for assessing gastric emptying, especially with respect to the diabetes population, and reviews newer diabetes therapies that decelerate the rate of gastric emptying. These therapies may be a beneficial tool in managing postprandial hyperglycaemia because they attenuate rapid surges in glucose concentrations by slowing the delivery of meal-derived glucose.

Relationship between clinical features and gastric emptying disturbances in diabetes mellitus

BACKGROUND AND OBJECTIVES

Gastric emptying (GE) may be delayed or rapid in diabetes mellitus. We sought to ascertain differences in risk factors or associated features (i.e. diabetic 'phenotype') among patients with diabetes who have rapid, slow or normal GE.

METHODS

From a database of patients in whom gastrointestinal transit was assessed by scintigraphy, we compared the diabetic phenotype in diabetic patients with rapid, slow and normal GE.

RESULTS

Of 129 patients, 55 (42%) had normal, 46 (36%) had delayed and 28 (22%) patients had rapid GE. In each GE category, there was an approximately equal number of type 1 and type 2 diabetes. In multivariable analyses, significant weight loss (OR, 2.81; 95% CI, 1.09-7.23) and neuropathy (OR, 3.60; 95% CI, 1.007-12.89) were the risk factors for delayed and rapid GE, respectively. Insulin therapy (OR, 0.08; 95% CI, 0.01-0.53) was associated with a lower risk of rapid compared to normal GE. However, other manifestations or characteristics of the diabetes 'phenotype' (i.e. type and duration of diabetes, glycosylated haemoglobin levels, and extraintestinal complications) were not useful for discriminating normal from delayed or rapid GE. At a specificity of 60%, clinical features were 73% sensitive for discriminating between normal and delayed GE and 80% sensitive for discriminating normal from rapid GE.

CONCLUSIONS

Diabetes is associated with slow and rapid GE. Because the diabetic phenotype is of limited utility for identifying disordered GE, GE should be assessed in patients with diabetes and gastrointestinal symptoms.

Relationship between genetic polymorphism and irritable bowel syndrome pathogenesis

Irritable bowel syndrome is a common functional disorder, whose etiology remains unknown. Previous researches indicated that its pathogenesis might be associated such factors as gastrointestinal motor abnormality, altered visceral sensation, psychological factors, neurotransmitter and imbalance of gastrointestinal flora, intestinal infection and food intolerance, etc. Besides, recent research has touched on relationship between genetics and IBS. This paper reviewed relationship between the inheritance, gene-linked polymorphism and irritable bowel syndrome pathogenesis.

Autonomic function at rest and in response to emotional and rectal stimuli in women with irritable bowel syndrome

Our aim was to study autonomic function in patients with Irritable bowel syndrome (IBS) without constipation and psychiatric comorbidity. Respiratory sinus arrhythmia (RSA) (representing cardiac vagal activity), skin conductance (representing sympathetic activity) and heart rate were measured at baseline and as a response to emotional stress and rectal discomfort in 33 women with IBS and 21 healthy women. Baseline heart rate was higher in the patients than in the healthy volunteers. Both groups had decreased RSA and increased heart rate and skin conductance level when exposed to emotional stress, but the autonomic responses did not differ significantly between the groups. At discomfort threshold the patients had increased heart rate response and skin conductance amplitude when compared to the healthy volunteers. Correlations between autonomic responses and the depression subscale of the Hospital Anxiety and Depression (HAD) score differed markedly between the diarrhea-predominant IBS patients and the IBS patients with alternating stool habits.

Lower gastrointestinal functions

The human colon serves to absorb water and electrolytes, store intraluminal contents until elimination is socially convenient, and salvage nutrients by bacterial metabolism of carbohydrates that have not been absorbed in the small intestine. The anorectum is responsible for fecal continence and defecation. This article is a broad perspective of the current status and a personal perspective of future challenges in understanding lower gastrointestinal functions in health and disease in humans.

Orthostatic intolerance and gastrointestinal motility in adolescents with nausea and abdominal pain

OBJECTIVE

To describe the relationships between gastric emptying, autonomic function, and postural tachycardia in adolescent patients with nausea and/or abdominal discomfort. It was hypothesized that patients with both gastrointestinal symptoms and symptoms of orthostatic intolerance are more likely to show abnormal tilt table results and delayed gastric emptying.

PATIENTS AND METHODS

A retrospective review was conducted of adolescent patients who came to a pediatric referral center because of nausea and dyspepsia and who subsequently underwent both autonomic reflex screening and gastric emptying testing. Patients with a heart rate change of 30 or more beats per minute on the heads-up tilt table test were assigned to the postural orthostatic tachycardia syndrome (POTS) group (n = 21), and those with a heart rate change of fewer than 30 beats per minute on the heads-up tilt table test were assigned to the non-POTS group (n = 10).

RESULTS

There was no significant difference between the POTS and non-POTS groups with regard to presenting symptoms (P > 0.05). Overall, 13 (42%) individuals had abnormal gastric emptying results (delayed in 6, accelerated in 7), but gastric emptying scores were similar between the POTS and non-POTS groups. Furthermore, there was no correlation between an individual's gastric emptying results at 1, 2, and 4 hours and that person's heart rate change on HUT (r = -0.05, -0.15, and -0.19).

CONCLUSIONS

Although altered gastric emptying and postural tachycardia are common in a referral population of adolescents with nausea and/or abdominal discomfort, the clinical presentation was not predictive of test results. Furthermore, delayed gastric emptying was not correlated with the current definition of postural tachycardia.

Sympathetic nerve dysfunction is common in patients with chronic intestinal pseudo-obstruction

GOAL

To clarify whether disturbances in the autonomic nervous system, reflected in abnormal cardiovascular reflexes, could explain symptoms of impaired heat regulation in patients with intestinal pseudo-obstruction.

BACKGROUND

Chronic intestinal pseudo-obstruction is a clinical syndrome characterized by diffuse, unspecific gastrointestinal symptoms due to damage to the enteric nervous system or the smooth muscle cells. These patients often complain of excessive sweating or feeling cold, suggesting disturbances in the autonomic nervous system. Earlier studies have pointed to a coexistence of autonomic disturbances in the enteric and cardiovascular nervous system.

STUDY

Thirteen consecutive patients (age range 23 to 79, mean 44 y) fulfilling the criteria for chronic intestinal pseudo-obstruction were investigated. Six of them complained of sweating or a feeling of cold. Examination of autonomic reflexes included heart rate variation to deep-breathing (expiration/inspiration index), heart rate reaction to tilt (acceleration index, brake index), and vasoconstriction (VAC) due to indirect cooling by laser doppler (VAC-index; high index indicates impaired VAC). Test results in patients were compared with healthy individuals.

RESULTS

Patients had significantly higher (more abnormal) median VAC-index compared with healthy controls [1.79 (interquartile ranges 1.89) vs. 0.08 (interquartile ranges 1.29); P=0.0007]. However, symptoms of impaired heat regulation were not related to the VAC-index. There were no differences in expiration/inspiration, acceleration index, or brake index between patients and controls.

CONCLUSIONS

The patients with severe gastrointestinal dysmotility showed impaired sympathetic nerve function which, however, did not seem to be associated with symptoms of impaired heat regulation.

Autonomic nervous system response to a solid meal and water loading in healthy children: its relation to gastric myoelectrical activity

The aim of this study was to investigate the correlation of gastric myoelectrical and autonomic activities in healthy children. Simultaneous recordings of electrogastrography (EGG) and electrocardiogram (ECG) were performed in healthy children before and after a solid meal and water loading respectively. The autonomic activity was assessed by spectral analysis of the heart rate variability (HRV). The solid meal resulted in an increase in EGG-dominant frequency (2.92 cpm vs 3.16 cpm, P < 0.05), dominant power (46.9 dB vs 53.7 dB, P < 0.05) and percentage normal slow waves (81.9%vs 89.0%, P < 0.05), while only dominant power increased following water loading. Power in the low-frequency band of HRV (LF) was significantly increased and power in the high-frequency band of HRV (HF) significantly decreased following the solid meal. Postprandial LF was positively and HF negatively correlated with the postprandial increase in EGG-dominant power. Water loading was not associated with any significant changes in HRV parameters. These results suggest that both vagal and sympathetic pathways are involved in modulation of gastric myoelectrical activity.

Sleep-related autonomic disturbances in symptom subgroups of women with irritable bowel syndrome

The objective was to investigate whether predominant symptom patterns in women with irritable bowel syndrome (IBS) affect autonomic activity during sleep. Seventy-five women with IBS underwent a polysomnographic sleep study. Twenty-two of the IBS patients were diarrhea-predominant (IBS-D), 33 were constipation-predominant (IBS-C), and 20 patients had alternating symptoms (IBS-A). Autonomic activity was measured by heart rate variability. The IBS-D group had significant vagal withdrawal compared to the IBS-A group during REM and non-REM sleep (P < 0.05). The IBS-D symptom subgroup had significantly (P < 0.05) greater sympathetic dominance during non-REM than IBS-A patients. Lower abdominal pain correlated with sympathetic dominance during sleep in the IBS-D group (r=0.54, P < 0.01). The IBS-D patients were physiologically distinct with regard to autonomic functioning during sleep compared to the alternating patients, but not the constipated patients. Sleep appears to unmask differences in autonomic activity that may distinguish IBS patients.

Upper gastrointestinal sensory-motor dysfunction in diabetes mellitus

Gastrointestinal (GI) sensory-motor abnormalities are common in patients with diabetes mellitus and may involve any part of the GI tract. Abnormalities are frequently sub-clinical, and fortunately only rarely do severe and life-threatening problems occur. The pathogenesis of abnormal upper GI sensory-motor function in diabetes is incompletely understood and is most likely multi-factorial of origin. Diabetic autonomic neuropathy as well as acute suboptimal control of diabetes has been shown to impair GI motor and sensory function. Morphological and biomechanical remodeling of the GI wall develops during the duration of diabetes, and may contribute to motor and sensory dysfunction. In this review sensory and motility disorders of the upper GI tract in diabetes is discussed; and the morphological changes and biomechanical remodeling related to the sensory-motor dysfunction is also addressed.