Relationship between esophageal dysfunction and neuropathy in diabetic patients

Dysphagia as a Manifestation of Endocrine and Metabolic Disorders

Dysphagia is a common manifestation of endocrine and metabolic diseases. Swallowing is a complex neuromuscular process, with an interplay of sensory and motor function, that has voluntary and involuntary control. Disruptions in any of these processes can cause significant dysphagia. Endocrine disorders and metabolic derangements are systemic conditions that affect multiple organ systems. They contribute to the development of neuropathies, myopathies, and motility disorders that lead to swallowing difficulty. Malnutrition and critical illness can lead to deconditioning and atrophy which can cause dysphagia, which in turn can lead to further malnutrition and deconditioning.

Sex difference in the associations among risk factors with gastroesophageal reflux disease in a large Taiwanese population study

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common global health issue. Previous studies have revealed a higher prevalence of GERD in females than in males, however few studies have investigated sex differences in the risk factors associated with GERD. Therefore, the aim of this population-based study was to examine sex differences in the risk factors for GERD in a large cohort of over 120,000 Taiwanese participants.

METHODS

We enrolled 121,583 participants (male: 43,698; female: 77,885; mean age 49.9 ± 11.0 years) from the Taiwan Biobank. The presence of GERD was ascertained using self-reported questionnaires. Sex differences in the risk factors associated with GERD were examined using multivariable logistic regression analysis.

RESULTS

The overall prevalence of GERD was 13.7%, including 13.0% in the male participants and 14.1% in the female participants (p < 0.001). Multivariable analysis showed that older age, hypertension, smoking history, alcohol history, low fasting glucose, and low uric acid were significantly associated with GERD in the male participants. In the female participants, older age, diabetes, hypertension, smoking history, alcohol history, low systolic blood pressure, low fasting glucose, high hemoglobin, high total cholesterol, low high-density lipoprotein cholesterol (HDL-C), low low-density lipoprotein cholesterol, and low uric acid were significantly associated with GERD. Significant interactions were found between sex and age (p < 0.001), diabetes (p < 0.001), smoking history (p < 0.001), fasting glucose (p = 0.002), triglycerides (p = 0.001), HDL-C (p = 0.001), and estimated glomerular filtration rate (p = 0.002) on GERD.

CONCLUSIONS

Our results showed a higher prevalence of GERD among females compared to males. Furthermore, sex differences were identified in the risk factors associated with GERD, and older age, diabetes, smoking history, and low HDL-C were more closely related to GERD in females than in males.

Chinese expert consensus on diagnosis and management of gastroesophageal reflux disease in the elderly (2023)

Gastroesophageal reflux disease (GERD) in the elderly is characterized by atypical symptoms, relatively severe esophageal injury, and more complications, and when GERD is treated, it is also necessary to fully consider the general health condition of the elderly patients. This consensus summarized the epidemiology, pathogenesis, clinical manifestations, and diagnosis and treatment characteristics of GERD in the elderly, and provided relevant recommendations, providing guidance for medical personnel to correctly understand and standardize the diagnosis and treatment of GERD in the elderly.

Risk factors and 26-years worldwide prevalence of endoscopic erosive esophagitis from 1997 to 2022: a meta-analysis

Erosive esophagitis (EE) is the part of gastroesophageal reflux disease (GERD) spectrum and may progress to esophageal adenocarcinoma. Due to its progressivity and unclear prevalence, we aim to identify the factors contributing in EE to decide the need for further examination. We performed a PRISMA 2020-based systematic search through PubMed and other resources up to June 2, 2022. Study quality was assessed using the Newcastle-Ottawa Scale (NOS). The odds ratio (OR) of each factor and worldwide prevalence of EE were measured. There are 114 observational studies included with a total of 759,100 participants. Out of 29 factors, the significant risk factors are age ≥ 60 y.o. (OR 2.03 [1.81-2.28]), White/Caucasian (OR 1.67 [1.40-1.99]), unmarried (OR 1.08 [1.03-1.14]), having GERD ≥ 5 years (OR 1.27 [1.14-1.42]), general obesity (OR 1.78 [1.61-1.98]), central obesity (OR 1.29 [1.18-1.42]), diabetes mellitus (DM) (OR 1.24 [1.17-1.32]), hypertension (OR 1.16 [1.09-1.23]), dyslipidemia (OR 1.15 [1.06-1.24]), hypertriglyceridemia (OR 1.42 [1.29-1.57]), hiatal hernia (HH) (OR 4.07 [3.21-5.17]), and non-alcoholic fatty liver disease (NAFLD) (OR 1.26 [1.18-1.34]). However, H. pylori infection (OR 0.56 [0.48-0.66]) and atrophic gastritis (OR 0.51 [0.31-0.86]) are protective towards EE. This study demonstrates that age, ethnicity, unmarried, long-term GERD, metabolic diseases, HH, and NAFLD act as risk factors for EE, whereas H. pylori infection and atrophic gastritis act as protective factors. These findings may enable a better understanding of EE and increase greater awareness to address its growing burden.

Detecting and treating the protean manifestations of diabetic autonomic neuropathy

The manifestations of diabetic autonomic neuropathy (DAN) are protean and clinically involve multiple systems, including the cardiovascular system, the gastrointestinal system, the genitourinary system as well as the sweat glands (sudomotor dysfunction) and the gallbladder. In addition, cardiac autonomic neuropathy (CAN) is associated with a correctible inability to appreciate and correct hypoglycaemia. While not a clinical problem, pupillary involvement should be the clue and the catalyst to investigate for other manifestations of DAN. This review outlines a practical approach to detecting and investigating the manifestations of DAN. Of particular importance is early detection of cardiovascular involvement where prompt therapy through glycaemic control can decrease the severity of CAN and decelerate the frequency and severity of retinopathy and nephropathy in addition to decreasing cardiovascular events and mortality. CAN also plays a role in accelerating other diabetic complications such as acute ischaemic stroke, heart failure, medial artery calcinosis, foot ulcers, peripheral artery disease and Charcot joints. Many therapies of DAN are available, which should not only decrease morbidity and mortality from DAN, but also improve the patient's quality of life. However, the therapies available are largely symptomatic.

Molecular Insights of Plant Phytochemicals Against Diabetic Neuropathy

Diabetes and its associated complications including diabetic neuropathy have become a menacing headache for health workers and scientists all over the world. The number of diabetic individuals has been growing exponentially every day while the entire medical fraternity feels crippled and unable to handle such an enormous and anarchical scenario. The disease also demonstrates itself in the patients in numerous ways ranging from a little discomfort to death. Diabetic neuropathy has a poor prognosis since it might go unnoticed for years after the onset of diabetes. The etiology of the disease has been linked to oxidative stress caused by increased free radical production. Hyperglycemia causes multiple metabolic pathways to be activated, as well as significant oxidative stress, which becomes the major cause of cell death, culminating in Diabetic Neuropathy. So, it is the need of the hour to find out permanent treatment for this life-threatening disease. The primary goal of this study is to emphasize the potential importance of numerous processes and pathways in the development of diabetic neuropathy as well as the possible role of plant metabolites to control the disease at a molecular level. A possible mechanism was also summarized in the study about scavenging the reactive oxygen species by a flavonoid component. The study also covered the in vivo data of various plants and some of the flavonoid compounds actively studied against Diabetic Neuropathy by inhibiting or reducing the contributing factors such as proinflammatory cytokines, ROS, RNS inhibition, and upregulating the various cellular antioxidants such as GSH, SOD, and CAT.

Sleep traits, fat accumulation, and glycemic traits in relation to gastroesophageal reflux disease: A Mendelian randomization study

Background

Sleep traits, fat accumulation, and glycemic traits are associated with gastroesophageal reflux disease (GERD) in observational studies. However, whether their associations are causal remains unknown. We performed a Mendelian randomization (MR) study to determine these causal relationships.

Methods

Independent genetic variants associated with insomnia, sleep duration, short sleep duration, body fat percentage, visceral adipose tissue (VAT) mass, type 2 diabetes, fasting glucose, and fasting insulin at the genome-wide significance level were selected as instrumental variables. Summary-level data for GERD were derived from a genome-wide association meta-analysis including 78,707 cases and 288,734 controls of European descent. Inverse variance weighted (IVW) was used for the main analysis, with weighted median and MR-Egger as complements to IVW. Sensitivity analyses were performed using Cochran's Q test, MR-Egger intercept test, and leave-one-out analysis to estimate the stability of the results.

Results

The MR study showed the causal relationships of genetically predicted insomnia (odds ratio [OR] = 1.306, 95% confidence interval [CI] 1.261 to 1.352; p = 2.24 × 10^-51), short sleep duration (OR = 1.304, 95% CI: 1.147 to 1.483, p = 4.83 × 10^-5), body fat percentage (OR = 1.793, 95% CI 1.496 to 2.149; p = 2.68 × 10^-10), and visceral adipose tissue (OR = 2.090, 95% CI 1.963 to 2.225; p = 4.42 × 10^-117) with the risk of GERD. There was little evidence for causal associations between genetically predicted glycemic traits and GERD. In multivariable analyses, genetically predicted VAT accumulation, insomnia, and decreased sleep duration were associated with an increased risk of GERD.

Conclusion

This study suggests the possible roles of insomnia, short sleep, body fat percentage, and visceral adiposity in the development of GERD.

Relationship Between Esophageal Motility Disorders and Autonomic Nervous System in Diabetic Patients: Pilot North African Study

Little attention has been given to esophageal disorders in diabetes mellitus. Pathophysiology of esophageal motility disorders (EMD) in patients with diabetes mellitus is multifactorial. The aims of the present study were: (a) to evaluate the prevalence of EMD in patients with Type 2 diabetes mellitus and (b) to determine the relationship between EMD and autonomic neuropathy as assessed by heart rate variability (HRV). All the patients completed a questionnaire about diabetes characteristics and gastrointestinal symptoms. Conventional esophageal manometry was performed in all patients. HRV was measured in three different situations (Lying Position 1, standing position, and Lying Position 2). The temporal and frequency domain parameters were considered for analysis. The prevalence of EMD in our patients was 60.5% (n = 23). Low score physical activity was significantly more frequent in patients with EMD (p = .03). There was an increase in sympathetic activity represented by the low frequency (LF) parameter (p = .027) in the presence of EMD. Whereas parasympathetic modulation of heart rate represented by the high frequency (HF) parameter (p = .027) was declined in patients with EMD compared to those without. The LF/HF ratio was significantly higher (p = .002) in patients with EMD. EMD were prevalent in diabetes mellitus and were associated to autonomic nervous system dysfunction predominantly at the parasympathetic component.

Comparison of High-Resolution Manometry in Patients Complaining of Dysphagia among Patients with or without Diabetes Mellitus

INTRODUCTION

Dysphagia is a common symptom that occurs in patients with diabetes mellitus (DM). There have been few prospective observational studies on esophageal motility disorders in DM using high-resolution manometry (HRM). This study aimed to clarify the characteristics of esophageal motility disorders using HRM in patients with dysphagia and compare them between DM and non-DM patients.

METHODS

Patients with dysphagia were prospectively recruited between October 2018 and July 2019. Patients (n = 89) underwent esophagogastroduodenoscopy and HRM and completed the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire. Manometry parameters and motility disorder classifications were compared between DM and non-DM patients. We also investigated the differences in clinical backgrounds and questionnaire scores among DM patients with normal and abnormal manometry results.

RESULTS

A higher prevalence of esophageal motility disorder was observed in DM patients (60%, 21/35) compared to non-DM patients (29.6%, 16/54) (p = 0.001). The prevalence of minor disorders such as ineffective esophageal motor disorder and fragmented peristalsis was significantly higher (45 vs. 11%), and the distal contractile integral, integrated relaxation pressure, and contractile front velocity values were lower in the DM group. Among DM patients, those with abnormal esophageal motility had a significantly higher prevalence of neuropathy, retinopathy, and nephropathy, as well as higher reflux or constipation scores on the GSRS, than those with normal results.

CONCLUSIONS

Among patients with dysphagia, the frequency of minor esophageal motility disorders was higher in DM patients than in non-DM patients. Abnormal esophageal motility related to poor esophageal clearance was associated with higher prevalence of diabetic complications.

Gastrointestinal autonomic neuropathy in diabetes

Gastrointestinal autonomic neuropathy represents an important and diverse, but poorly appreciated, manifestation of diabetic autonomic neuropathy that impacts negatively on quality of life. There is no test to assess gastrointestinal autonomic nerve damage directly in humans; cardiovascular autonomic reflex tests are often used as a surrogate, but are suboptimal. Gastrointestinal symptoms are common in diabetes, but usually correlate only weakly with disordered motility. Diabetic gastroparesis, or abnormally delayed gastric emptying, occurs frequently and is the best characterized manifestation of gastrointestinal autonomic neuropathy. There is a bi-directional relationship between postprandial glycaemia and the rate of gastric emptying. However, autonomic neuropathy can affect the function of any gut segment from the esophagus to the anus. Current management options for gastrointestinal autonomic neuropathy are, for the main part, empirical and sub-optimal.

Association of decreased variation of coefficient R-R interval with ischemic colitis and small bowel obstruction

Background

The parasympathetic nervous system exerts and controls intestinal tone. Several studies have suggested that the coefficient of the R–R intervals (CVRR) is useful for evaluating the parasympathetic nervous system.

Objectives

This study aimed to evaluate the relationship between gastrointestinal emergencies, specifically ischemic colitis (IC) and small bowel obstruction (SBO), and the autonomic nervous system.

Methods

In this retrospective study, a total of 13 patients with IC or SBO aged ≧65 years were analyzed. CVRR was measured in patients with IC and SBO and controls.

Results

CVRR averaged to 8.8% ± 2.5% in controls, 1.4% ± 0.4% in patients with IC, and 2.4% ± 1.0% in SBO groups (p < 0.001). CVRR was significantly lower in patients with IC and SBO than that in controls.

Conclusion

The results of this study demonstrate the possibility that CVRR may serve as a clinical index for assessing the functioning of the parasympathetic nervous system in patients with IC or SBO.

Diabetes in relation to Barrett's esophagus and adenocarcinomas of the esophagus: A pooled study from the International Barrett's and Esophageal Adenocarcinoma Consortium

BACKGROUND

Diabetes is positively associated with various cancers, but its relationship with tumors of the esophagus/esophagogastric junction remains unclear.

METHODS

Data were harmonized across 13 studies in the International Barrett's and Esophageal Adenocarcinoma Consortium, comprising 2309 esophageal adenocarcinoma (EA) cases, 1938 esophagogastric junction adenocarcinoma (EGJA) cases, 1728 Barrett's esophagus (BE) cases, and 16,354 controls. Logistic regression was used to estimate study-specific odds ratios (ORs) and 95% CIs for self-reported diabetes in association with EA, EGJA, and BE. Adjusted ORs were then combined using random-effects meta-analysis.

RESULTS

Diabetes was associated with a 34% increased risk of EA (OR, 1.34; 95% CI, 1.00-1.80; I2  = 48.8% [where 0% indicates no heterogeneity, and larger values indicate increasing heterogeneity between studies]), 27% for EGJA (OR, 1.27; 95% CI, 1.05-1.55; I2  = 0.0%), and 30% for EA/EGJA combined (OR, 1.30; 95% CI, 1.06-1.58; I2  = 34.9%). Regurgitation symptoms modified the diabetes-EA/EGJA association (P for interaction = .04) with a 63% increased risk among participants with regurgitation (OR, 1.63; 95% CI, 1.19-2.22), but not among those without regurgitation (OR, 1.03; 95% CI, 0.74-1.43). No consistent association was found between diabetes and BE.

CONCLUSIONS

Diabetes was associated with increased EA and EGJA risk, which was confined to individuals with regurgitation symptoms. Lack of an association between diabetes and BE suggests that diabetes may influence progression of BE to cancer.

Chronic cough in the elderly

Chronic cough is a multi-factorial syndrome commonly presenting as cough hypersensitivity in adult patients. It is a common medical condition in the communities but is more prevalent in older adults. Elderly patients (≥65 years) frequently suffer from multiple comorbidities, which may lead to more clinical heterogeneity in chronic cough and pose diagnostic and therapeutic challenges. Hyposensitivity in cough reflex, probably resulting from central nervous system illnesses, is another potential concern. Despite these complexities and challenges, elderly-specific issues have rarely been addressed in current clinical practice guidelines for chronic cough. Considering recent trends in global population aging, the burden of elderly chronic cough is expected to increase into the near future. This review aimed to respond to following clinical questions: (1) is chronic cough a more heterogeneous condition in the elderly compared to younger adults; and (2) are there additional considerations when choosing the diagnostic and therapeutic approaches to this condition in the elderly?

Diabetes in the practice of otolaryngology

Diabetes mellitus is the most common endocrine disease, characterized by chronic hyperglycemia. The hyperglycemic milieu leads to endothelial injury in blood vessels of variant size, which results in microangiopathy and macroangiopathy (atherosclerosis). Consequential ischemia of nerves and hyperglycemia by itself lead to nerve degeneration and generalized neuropathy, affecting most often the sensory peripheral nerves and the autonomic nervous system. Auditory, vestibular and olfactory sensorium may be compromised by DM. People with DM have an increased susceptibility to infection, as a result of neutrophil dysfunction and impaired humoral immunity. Therefore DM predisposes to certain infectious diseases, such as fungal sinusitis or malignant otitis externa, which are rare in general population. Recovery from infections or from injuries may be compromised by coexisting DM. In this review we discuss complications of DM in the head and neck region. Otolaryngologists and general practitioners should be alert to specific conditions related to DM and be minded of the relevant complications and consequences.

Clinical factors associated with the symptoms of constipation in patients with diabetes mellitus: A multicenter study

BACKGROUND AND AIM

Changes in treatment protocols for patients with diabetes mellitus (DM) may influence the functions of the digestive tract. This study examined possible clinical factors associated with the symptoms of constipation in patients with DM.

METHODS

This was a multicenter study. Participants were consecutive Japanese patients undergoing treatment for type 1 or type 2 DM. Constipation was evaluated using the gastrointestinal symptom rating scale. Diabetic neuropathy was evaluated by the presence or absence of peripheral neuropathy of the lower limbs.

RESULTS

Of 419 participants, 258 were men and 161 women (ratio: 1.6:1), with a mean age of 63.6 ± 12.5 years. In multivariate analysis, symptoms of constipation were significantly associated with age (odds ratio [OR] = 1.02, 95% confidence interval [CI]: 1.01-1.04, P = 0.032), lower mental component summary (OR = 3.31, 95% CI: 1.69-6.48, P < 0.001), diabetic retinopathy (OR = 1.99, 95% CI: 1.14-3.45, P = 0.015), and diabetic neuropathy (OR = 1.86, 95% CI: 1.10-3.16, P = 0.021). In patients with peripheral neuropathy of the lower limbs, regardless of the presence of other complications (diabetic nephropathy and diabetic retinopathy), the prevalence of symptoms of constipation was twice that of patients without peripheral neuropathy (40.0-49.1% vs 22.0%). Diabetic drugs were not associated with symptoms of constipation.

CONCLUSIONS

Diabetic neuropathy, defined as peripheral neuropathy of the lower limbs, was significantly associated with symptoms of constipation. Peripheral neuropathy of the lower limbs is not a direct risk factor for constipation but may be a useful criterion when assessing whether constipation is associated with DM.

Distribution of Esophageal Motor Disorders in Diabetic Patients With Dysphagia

BACKGROUND

Diabetes mellitus can cause various gastrointestinal symptoms. Assessment of esophageal dysmotility in diabetic patients has been scarcely studied. The aim of this study was to determine the esophageal motor characteristics of diabetic versus nondiabetic patients who present with dysphagia.

METHODS

High-resolution esophageal manometries (HREMs) of 83 diabetic patients and 83 age and gender-matched nondiabetic patients with dysphagia from 2 medical centers were included in this study. Demographic information, medical comorbidities, and medication usage were recorded for each patient in a single registry. HREM of each patient was evaluated and the different functional parameters were recorded.

KEY RESULTS

Overall, 46% of diabetic patients were found to have an esophageal motor disorder. Diabetic patients with dysphagia were more likely to have failed swallows on HREM (50.6% vs. 33.7%; P=0.03) as compared with nondiabetic patients. Among diabetic patients, those being treated with insulin were more likely to have failed (69.0% vs. 40.7%; P=0.01) and weak (65.5% vs. 33.3%; P=0.005) swallows as compared with diabetic patients not on insulin. Among diabetic patients, those with abnormal manometry were more likely to demonstrate diabetic retinopathy (27.0% vs. 8.7%; P=0.04). There was a trend toward increased incidence of esophagogastric junction outflow obstruction in diabetic patients (10.8% vs. 2.4%; P=0.057) as compared with nondiabetic patients.

CONCLUSIONS

Nearly half of diabetic patients with dysphagia have some type of an esophageal motility disorder. Diabetic retinopathy and the use of insulin are predictive of esophageal motor abnormalities among diabetic patients.

Diabetes-induced mechanophysiological changes in the esophagus

Esophageal disorders are common in diabetes mellitus (DM) patients. DM induces mechanostructural remodeling in the esophagus of humans and animal models. The remodeling is related to esophageal sensorimotor abnormalities and to symptoms frequently encountered by DM patients. For example, gastroesophageal reflux disease (GERD) is a common disorder associated with DM. This review addresses diabetic remodeling of esophageal properties and function in light of the Esophagiome, a scientifically based modeling effort to describe the physiological dynamics of the normal, intact esophagus built upon interdisciplinary approaches with applications for esophageal disease. Unraveling the structural, biomechanical, and sensory remodeling of the esophagus in DM must be based on a multidisciplinary approach that can bridge the knowledge from a variety of scientific disciplines. The first focus of this review is DM-induced morphodynamic and biomechanical remodeling in the esophagus. Second, we review the sensorimotor dysfunction in DM and how it relates to esophageal remodeling. Finally, we discuss the clinical consequences of DM-induced esophageal remodeling, especially in relation to GERD. The ultimate aim is to increase the understanding of DM-induced remodeling of esophageal structure and sensorimotor function in order to assist clinicians to better understand the esophageal disorders induced by DM and to develop better treatments for those patients.

Review of gastroesophageal reflux disease (GERD) in the diabetic patient

This article reviews the known pathophysiological mechanisms of comorbid gastroesophageal reflux disease (GERD) in the diabetic patient, discusses therapeutic options in care, and provides an approach to its evaluation and management. We searched for review articles published in the past 10 years through a PubMed search using the filters diabetes mellitus, GERD, pathophysiology, and management. The search only yielded a handful of articles, so we independently included relevant studies from these review articles along with related citations as suggested by PubMed. We found diabetic patients are more prone to developing GERD and may present with atypical manifestations. A number of mechanisms have been proposed to elucidate the connection between these two diseases. Studies involving treatment options for comorbid disease suggest conflicting drug-drug interactions. Currently, there are no published guidelines specifically for the evaluation and management of GERD in the diabetic patient. Although there are several proposed mechanisms for the higher prevalence of GERD in the diabetic patient, this complex interrelationship requires further research. Understanding the pathophysiology will help direct diagnostic evaluation. In our review, we propose a management algorithm for GERD in the diabetic patient.

Association between diabetes mellitus and gastroesophageal reflux disease: A meta-analysis

AIM: To investigate whether there is a link between diabetes mellitus (DM) and gastroesophageal reflux disease (GERD).

METHODS: We conducted a systematic search of PubMed and Web of Science databases, from their respective inceptions until December 31, 2013, for articles evaluating the relationship between DM and GERD. Studies were selected for analysis based on certain inclusion and exclusion criteria. Data were extracted from each study on the basis of predefined items. A meta-analysis was performed to compare the odds ratio (OR) in DM between individuals with and without GERD using a fixed effect or random effect model, depending on the absence or presence of significant heterogeneity. Subgroup analyses were used to identify sources of heterogeneity. Publication bias was assessed by Begg’s test. To evaluate the results, we also performed a sensitivity analysis.

RESULTS: When the electronic database and hand searches were combined, a total of nine eligible articles involving 9067 cases and 81 968 controls were included in our meta-analysis. Based on the random-effects model, these studies identified a significant association between DM and the risk of GERD (overall OR = 1.61; 95%CI: 1.36-1.91; P = 0.003). Subgroup analyses indicated that this result persisted in studies on populations from Eastern countries (OR = 1.71; 95%CI: 1.38-2.12; P = 0.003) and in younger patients (mean age < 50 years) (OR = 1.70; 95%CI: 1.22-2.37; P = 0.001). No significant publication bias was observed in this meta-analysis using Begg^’s test (P = 0.175). The sensitivity analysis also confirmed the stability of our results.

CONCLUSION: This meta-analysis suggests that patients with DM are at greater risk of GERD than those who do not have DM.

Diabetic gastrointestinal motility disorders and the role of enteric nervous system: current status and future directions

BACKGROUND

Gastrointestinal manifestations of diabetes are common and a source of significant discomfort and disability. Diabetes affects almost every part of gastrointestinal tract from the esophagus to the rectum and causes a variety of symptoms including heartburn, nausea, vomiting, abdominal pain, diarrhea and constipation. Understanding the underlying mechanisms of diabetic gastroenteropathy is important to guide development of therapies for this common problem. Over recent years, the data regarding the pathophysiology of diabetic gastroenteropathy is expanding. In addition to autonomic neuropathy causing gastrointestinal disturbances the role of enteric nervous system is becoming more evident.

PURPOSE

In this review, we summarize the reported alterations in enteric nervous system including enteric neurons, interstitial cells of Cajal and neurotransmission in diabetic animal models and patients. We also review the possible underlying mechanisms of these alterations, with focus on oxidative stress, growth factors and diabetes induced changes in gastrointestinal smooth muscle. Finally, we will discuss recent advances and potential areas for future research related to diabetes and the ENS such as gut microbiota, micro-RNAs and changes in the microvasculature and endothelial dysfunction.

Gastrointestinal complications of diabetes

This review provides an overview of the vast gastrointestinal tract complications of diabetes that can occur from the mouth to the anus. The presentation, diagnosis, and management of gastrointestinal disorders, ranging from gastroparesis, celiac disease, and bacterial overgrowth to nonalcoholic fatty liver disease, are reviewed to heighten awareness. When managing care of patients with diabetes, one should keep in mind the potential gastrointestinal complications, as well as the frequent disorders that are not related to diabetes.

Cough in the elderly population: relationships with multiple comorbidity

BACKGROUND

The epidemiology of cough in the elderly population has not been studied comprehensively. The present study aimed to investigate the epidemiology of cough in a community elderly population, particularly in relation with their comorbidity.

METHODS

A cross-sectional analysis was performed using a baseline dataset from the Korean Longitudinal Study on Health and Aging, a community-based elderly population cohort study. Three types of cough (frequent cough, chronic persistent cough, and nocturnal cough) were defined using questionnaires. Comorbidity was examined using a structured questionnaire. Health-related quality of life was assessed using the Short Form 36 questionnaire.

RESULTS

The prevalence was 9.3% for frequent cough, 4.6% for chronic persistent cough, and 7.3% for nocturnal cough. In multivariate logistic regression analyses, smoking, asthma and allergic rhinitis were found to be risk factors for cough in the elderly. Interestingly, among comorbidities, constipation and uncontrolled diabetes mellitus (HbA1c ≥ 8%) were also found to have positive associations with elderly cough. In the Short Form 36 scores, chronic persistent cough was independently related to impairment of quality of life, predominantly in the mental component.

CONCLUSIONS

Cough has a high prevalence and is detrimental to quality of life in the elderly. Associations with smoking, asthma and rhinitis confirmed previous findings in younger populations. Previously unrecognised relationships with constipation and uncontrolled diabetes mellitus suggested the multi-faceted nature of cough in the elderly.

Esophageal body motility in people with diabetes: comparison with non-diabetic healthy individuals

AIMS

The aim of this study was to compare esophageal motor characteristics between diabetics and healthy individuals.

METHODS

Esophageal manometry was performed in 34 type 2 diabetics and 32 healthy individuals. Waves were evaluated in the 3 thirds of the esophagus (P1=upper, P2=middle, and P3=distal).

RESULTS

In diabetics vs. controls, wave distribution was as follows: peristaltic waves, 83.5 ± 22.2% vs. 96.3 ± 4.4%, p<0.002; simultaneous waves, 3.26 ± 5.8% vs. 0.53 ± 1.3%, p<0.01; no transmitted waves, 10.62 ± 20.7% vs. 2.75 ± 3.0%, p<0.002; and retrograde waves, 2.68 ± 4.0% vs. 0.31 ± 1.1%, p<0.03. Wave amplitude was similar between groups. Average upstroke (mmHg/s) in diabetics vs. non-diabetics was P2, 33.8 ± 13.9 vs. 40.2 ± 17.7, p<0.03; and P3, 29.8 ± 15.3 vs. 41.3 ± 14.0, p<0.002.

CONCLUSIONS

(1) Simultaneous waves, no transmitted waves, and retrograde esophageal waves were significantly more frequent in diabetics. (2) Average upstroke was significantly lower within the middle and distal esophagus of diabetic individuals. (3) Wave amplitude was similar in both groups.

Assessment of gastroesophageal reflux disease by serodiagnosis of Helicobacter pylori-related chronic gastritis stage

AIM: To evaluate the association of Helicobacter pylori (H.pylori)-related chronic gastritis stage with upper gastrointestinal symptoms and gastroesophageal reflux disease (GERD).

METHODS: Subjects underwent upper gastrointestinal endoscopy, a questionnaire using a frequency scale for symptoms of GERD (FSSG), and measurements of serum H.pylori-antibody and pepsinogen (PG) levels. They were classified into the following 4 groups in terms of H.pylori-related chronic gastritis stage: Group A (n = 219), H.pylori(-)PG(-); Group B (n = 310), H.pylori(+)PG(-); Group C (n = 279), H.pylori(+)PG(+); and Group D (n = 17), H.pylori(-)PG(+).

RESULTS: Reflux esophagitis occurred in 30.6% of Group A, 14.5% of Group B, 6.8% of Group C, and 0% of Group D (P < 0.001). Scores for acid reflux symptoms decreased significantly with chronic gastritis stage (from Group A to D) (P < 0.05), while scores for dysmotility symptoms did not differ significantly. The prevalence of non-erosive reflux disease (NERD) did not differ among groups. However, in subjects with GERD, the prevalence of NERD tended to increase with chronic gastritis stage (P = 0.081).

CONCLUSION: Acid reflux symptoms and the prevalence of reflux esophagitis can be assessed by measuring both serum H.pylori-antibody and PG levels.

[Swallowing disorders, pneumonia and respiratory tract infectious disease in the elderly]

Swallowing disorders (or dysphagia) are common in the elderly and their prevalence is often underestimated. They may result in serious complications including dehydration, malnutrition, airway obstruction, aspiration pneumonia (infectious process) or pneumonitis (chemical injury caused by the inhalation of sterile gastric contents). Moreover the repercussions of dysphagia are not only physical but also emotional and social, leading to depression, altered quality of life, and social isolation. While some changes in swallowing may be a natural result of aging, dysphagia in the elderly is mainly due to central nervous system diseases such as stroke, parkinsonism, dementia, medications, local oral and oesophageal factors. To be effective, management requires a multidisciplinary team approach and a careful assessment of the patient's oropharyngeal anatomy and physiology, medical and nutritional status, cognition, language and behaviour. Clinical evaluation can be completed by a videofluoroscopic study which enables observation of bolus movement and movements of the oral cavity, pharynx and larynx throughout the swallow. The treatment depends on the underlying cause, extent of dysphagia and prognosis. Various categories of treatment are available, including compensatory strategies (postural changes and dietary modification), direct or indirect therapy techniques (swallow manoeuvres, medication and surgical procedures).

Epidemiology and clinical characteristics of GERD in the Japanese population

We reviewed articles on the epidemiology and clinical characteristics of gastroesophageal reflux disease (GERD) in Japan to clarify these features of GERD in this country. Although the definition of GERD depends on the individual study, the prevalence of GERD has been increasing since the end of the 1990s. The reasons for the increase in the prevalence of GERD may be due to increases in gastric acid secretion, a decrease in the Helicobacter pylori infection rate, more attention being paid to GERD, and advances in the concept of GERD. More than half of GERD patients had non-erosive reflux disease, and the majority (87%) of erosive esophagitis was mild type, such as Los Angeles classification grade A and grade B. There were several identified risk factors, such as older age, obesity, and hiatal hernia. In particular, mild gastric atrophy and absence of H. pylori infection influence the characteristics of GERD in the Japanese population. We also discuss GERD in the elderly; asymptomatic GERD; the natural history of GERD; and associations between GERD and peptic ulcer disease and H. pylori eradication. We examined the prevalence of GERD in patients with specific diseases, and found a higher prevalence of GERD, compared with that in the general population, in patients with diabetes mellitus, those with obstructive sleep apnea syndrome, and those with bronchial asthma. We provide a comprehensive review of GERD in the Japanese population and raise several clinical issues.

Prevalence of GORD (gastro-oesophageal reflux disease) in Type 2 diabetes and a comparison of clinical profiles between diabetic patients with and without GORD

AIMS

To examine the incidence of gastro-oesophageal reflux disease (GORD) and its associated factors in patients with Type 2 diabetes mellitus (Type 2 DM).

METHODS

In 859 Type 2 DM outpatients, we conducted a QUEST inquiry and considered those showing a QUEST score of 4 or higher as having GORD. We surveyed clinical variables (physical findings, gender, age, duration of disease, glycated haemoglobin (HbA(1c)), type of oral glucose-lowering agent, presence or absence of insulin therapy, complications, and presence or absence of agents that may be associated with GORD [Ca channel blocker (CCB) anti-platelet agents]) to investigate their association with the onset of GORD.

RESULTS

We analysed 813 subjects, of whom 56.6% were male. The mean age was 63.7 +/- 11.3 years and HbA(1c) 7.2 +/- 1.2%. The incidence of GORD was 29.0% (n = 221). GORD was positively correlated with body weight, body mass index (BMI) and HbA(1c). It was negatively correlated with age, serum creatinine and proportion of patients treated with pioglitazone or CCB. In addition, GORD was more common in females. The incidence of GORD was significantly higher in younger patients.

CONCLUSIONS

Previous studies have suggested a relationship of GORD with pioglitazone/CCB. However, the results of this study do not support this; these agents may not induce GORD.

Characterization of upper thoracic spinal neurons responding to esophageal distension in diabetic rats

The aim of this study was to examine spinal neuronal processing of innocuous and noxious mechanical inputs from the esophagus in diabetic rats. Streptozotocin (50 mg/kg, ip) was used to induce diabetes in 15 male Sprague-Dawley rats, and vehicle (10 mM citrate buffer) was injected into 15 rats as control. Four to eleven weeks after injections, extracellular potentials of single thoracic (T3) spinal neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated rats. Esophageal distensions (ED, 0.2, 0.4 ml, 20 s) were produced by water inflation of a latex balloon in the thoracic esophagus. Noxious ED (0.4 ml, 20 s) altered activity of 44% (55/126) and 38% (50/132) of spinal neurons in diabetic and control rats, respectively. The short-lasting excitatory responses to ED were encountered more frequently in diabetic rats (27/42 vs 15/41, P<0.05). Spinal neurons with low threshold for excitatory responses to ED were more frequently encountered in diabetic rats (33/42 vs 23/41, P<0.05). However, mean excitatory responses and duration of responses to noxious ED were significantly reduced for high-threshold neurons in diabetic rats (7.4+/-1.1 vs 13.9+/-3.3 imp/s; 19.0+/-2.3 vs 31.2+/-5.5 s; P<0.05). In addition, more large size somatic receptive fields were found for spinal neurons with esophageal input in diabetic rats than in control rats (28/42 vs 19/45, P<0.05). These results suggested that diabetes influenced response characteristics of thoracic spinal neurons receiving mechanical esophageal input, which might indicate an altered spinal visceroceptive processing underlying diabetic esophageal neuropathy.

Esophageal function worsens with long duration of diabetes

BACKGROUND

The aim of this study was to assess the relationship between the duration of diabetes and esophageal dysfunction.

METHODS

We examined 66 patients with type 2 diabetes. Duration of diabetes was determined by asking patients and from their medical records. The patients were divided into three groups according to the duration of their diabetes: group A, 1-4 years, n=26; group B, 5-9 years, n=20; and group C, 10+ years, n=20. Ambulatory esophageal 24-h pH and motility were monitored, and gastroesophageal reflux and esophageal motility disorders were estimated in detail.

RESULTS

When the duration of diabetes was long, the percentage of time with pH<4 tended to increase. The amplitude of esophageal peristaltic waves and the frequency of effective peristalsis were reduced when the duration of diabetes was long. A significant correlation was observed between the duration of diabetes and the frequency of effective peristalsis. The number of esophageal peristaltic waves per minute and the percentage of multipeaked peristaltic waves increased significantly in group B, and decreased when the duration of diabetes became longer.

CONCLUSIONS

Gastroesophageal reflux and esophageal motility disorders worsened with long duration of diabetes. These esophageal dysfunctions should be considered in patients with long-standing diabetes.

Therapy Insight: gastrointestinal complications of diabetes--pathophysiology and management

Patients with diabetes often have gastrointestinal symptoms, but the extent and severity of this problem and the specificity of the symptoms are not nearly as well defined as frequently assumed. Any part of the gastrointestinal tract can be affected, and the presenting symptoms depend on the composite of dysfunctional elements. Gastroesophageal reflux, Candida esophagitis, gastroparesis, diarrhea and constipation are among the many common gastrointestinal complications of diabetes. No specific risk factor for the development of these complications has been identified and their etiology is most likely to be multifactorial, involving both reversible and irreversible processes. Treatment should be directed at tighter glycemic and symptom control, which can bring about clinical improvement for many patients. For other patients, however, effective clinical management is problematic because no therapies are available to prevent or correct the underlying disease mechanisms. Studies now suggest that reduced levels of key trophic factors cause transdifferentiation of pacemaker interstitial cells of Cajal into a smooth-muscle-like phenotype. If this really is the case, therapies directed at restoring the normal milieu of trophic signals could correct the dysfunction of the interstitial cells of Cajal and resolve many gastrointestinal complications. Advances in stem cell technology also hold promise to provide a cure for diabetes and to correct abnormalities in gastrointestinal pathology.

Plasma ghrelin concentrations in different clinical stages of diabetic complications and glycemic control in Japanese diabetics

Ghrelin is an acylated 28-amino-acid peptide that stimulates food intake, GH secretion, and gastric motility. Experimental studies have suggested that ghrelin plays roles in glucose homeostasis, atherosclerosis, and microangiopathy. We investigated possible involvement of ghrelin in micro- and macro-vascular diabetic complications and glycemic control in diabetic patients. Fasting and postprandial plasma ghrelin concentrations after a test meal were measured in 108 and 61 Japanese diabetic patients, respectively. Plasma ghrelin concentrations were negatively correlated with body mass index (BMI) (r = -0.309, P = 0.002) or HbA(1c) (r = -0.264, P = 0.0065). Plasma ghrelin levels in patients with diabetic nephropathy who showed high serum creatinine levels (s-Cre) were significantly higher than those in patients who showed normal s-Cre (P<0.02). In patients with diabetic triopathy, plasma ghrelin concentrations were significantly lower than those in patients without diabetic complications (P<0.05). Stepwise multiple regression analyses revealed that s-Cre, BMI, and HbA(1c) were independently associated with plasma ghrelin levels. A postprandial decrease of ghrelin was observed in patients with normal CV(R-R) values or those with normal body weight, whereas it was not seen in obese patients or in patients with low CV (R-R) values. Suppression rates of ghrelin 30-60 min after a test meal in obese patients were significantly lower than those in normal-weight patients. These findings suggest that ghrelin secretion is suppressed by long-term hyperglycemia and that obesity influences the regulation of ghrelin secretion.

Impaired contractility and remodeling of the upper gastrointestinal tract in diabetes mellitus type-1

AIM: To investigate that both the neuronal function of the contractile system and structural apparatus of the gastrointestinal tract are affected in patients with longstanding diabetes and auto mic neuropathy.

METHODS: The evoked esophageal and duodenal contractile activity to standardized bag distension was assessed using a specialized ultrasound-based probe. Twelve type-1 diabetic patients with autonomic neuropathy and severe gastrointestinal symptoms and 12 healthy controls were studied. The geometry and biomechanical parameters (strain, tension/stress, and stiffness) were assessed.

RESULTS: The diabetic patients had increased frequency of distension-induced contractions (6.0 ± 0.6 vs 3.3 ± 0.5, P < 0.001). This increased reactivity was correlated with the duration of the disease (P = 0.009). Impaired coordination of the contractile activity in diabetic patients was demonstrated as imbalance between the time required to evoke the first contraction at the distension site and proximal to it (1.5 ± 0.6 vs 0.5 ± 0.1, P = 0.03). The esophageal wall and especially the mucosa-submucosa layer had increased thickness in the patients (P < 0.001), and the longitudinal and radial compressive stretch was less in diabetics (P < 0.001). The esophageal and duodenal wall stiffness and circumferential deformation induced by the distensions were not affected in the patients (all P > 0.14).

CONCLUSION: The impaired contractile activity with an imbalance in the distension-induced contractions likely reflects neuronal abnormalities due to autonomic neuropathy. However, structural changes and remodeling of the gastrointestinal tract are also evident and may add to the neuronal changes. This may contribute to the pathophysiology of diabetic gut dysfunction and impact on future management of diabetic patients with gastrointestinal symptoms.

Oesophageal motility disorders in type 1 diabetes mellitus and their relation to cardiovascular autonomic neuropathy

The relationship between cardiovascular autonomic neuropathy (CVAN) and oesophageal dysfunction in diabetes mellitus has not been well established because reports are contradictory. The aim of this study was to assess oesophageal function and its correlation with CVAN in type 1 diabetic patients without oesophageal symptoms. Forty-six type 1 diabetic patients without oesophageal symptoms (DG) and 34 healthy volunteers (CG) were studied. Both groups underwent CVAN tests and oesophageal manometry and pH-metry. Differences between groups regarding results of cardiovascular autonomic tests and oesophageal studies were statistically analysed. Compared with the CG, the DG group showed insufficient lower oesophageal sphincter (LOS) relaxation and a higher percentage of simultaneous waves (P < 0.01). Patients with CVAN (n = 22) showed a higher prevalence of pathological simultaneous contractions (>10%), and the prevalence of simultaneous waves related to the degree of autonomic neuropathy was: 9% of patients without CVAN, 7% of those suspected to have it and 50% of patients with CVAN (P < 0.001). Factors associated with the presence of pathological simultaneous waves (>10%) were the presence of CVAN and duration of diabetes (P < 0.05, logistic regression analysis). Increase in simultaneous waves and impaired relaxation of LOS are more frequent in diabetic patients with CVAN.

Biomechanical properties of the layered oesophagus and its remodelling in experimental type-1 diabetes

Passive biomechanical properties in term of the stress-strain relationship and the shear modulus were studied in separated muscle layer and mucosa-submucosa layer in the oesophagus of normal and STZ (streptozotocin)-induced diabetic rats. The mucosa-submucosa and muscle layers were separated using microsurgery and studied in vitro using a self-developed test machine. Stepwise elongation and inflation plus continuous twist were applied to the samples. A constitutive equation based on a strain energy function was used for the stress-strain analysis. Five material constants were obtained for both layers. The mucosa-submucosa layer was significantly stiffer than the muscle layer in longitudinal, circumferential and circumferential-longitudinal shear direction. The mechanical constants of the oesophagus show that the oesophageal wall was anisotropic, the stiffness in the longitudinal direction was higher than in the circumferential direction in the intact oesophagus (P < 0.001) and in the muscle layer (P < 0.05). Diabetes-induced pronounced increase in the outer perimeter, inner perimeter and lumen area in both the muscle and mucosa-submucosa layer. The growth of the mucosa-submucosa layer (P < 0.001) was more pronounced than the muscle layer (P < 0.05). Furthermore, the circumferential stiffness of the mucosa-submucosa layer increased 28 days after STZ treatment. In conclusion, the oesophagus is a non-homogeneous anisotropic tube. Thus, the mechanical properties differed between layers as well as in different directions. Morphological and biomechanical remodelling is prominent in the diabetic oesophagus.

Is the questionnaire for the assessment of gastroesophageal reflux useful for diabetic patients?

OBJECTIVE

It has been suggested that the questionnaire reported by Carlsson et al. has high sensitivity in diagnosing gastroesophageal reflux disease (GERD) and is considered to be one of the most useful diagnostic tools for GERD. The aim of the present study was to evaluate the ability of the questionnaire to identify gastroesophageal reflux (GER) diagnosed by 24-h pH monitoring in diabetic patients.

MATERIAL AND METHODS

Fifty-three patients with type 2 diabetes were enrolled in the present study. GER was monitored by means of an antimony electrode. Patients completed the questionnaires immediately before undergoing pH monitoring.

RESULTS

Diabetic patients were found to have few symptoms, and the average score on the questionnaire was extremely low. No significant difference in scores on the questionnaire was observed between patients with and those without GER.

CONCLUSIONS

The questionnaire was shown not to be useful for diagnosing GER as a complication in diabetic patients. We, therefore, should not diagnose GER as a complication in diabetes mellitus on the basis of the questionnaire.

Morphologic and biomechanical changes of rat oesophagus in experimental diabetes

AIM: To study morphologic and biomechanical changes of oesophagus in diabetes rats.

METHODS: Diabetes was induced by a single injection of streptozotocin (STZ). The type of diabetes mellitus induced by parenteral STZ administration in rats was insulin-dependent (type I). The samples were excised and studied in vitro using a self-developed biomaterial test machine.

RESULTS: The body mass was decreased after 4 d with STZ treatment. The length of esophagus shortened after 4, 7, 14 d. The opening angle increased after 14 d. The shear, longitudinal and circumferential stiffness were obviously raised after 28 d of STZ treatment.

CONCLUSION: The changes of passive biomechanical properties reflect intra-structural alteration of tissue to a certain extent. This alteration will lead to some dysfunction of movement. For example, tension of esophageal wall will change due to some obstructive disease.