Small Intestinal Transit Time Is Delayed in Small Intestinal Bacterial Overgrowth

Whole Gut Transit Scintigraphy for the Assessment of Patients with Symptoms of Chronic Constipation

INTRODUCTION

Whole gut transit scintigraphy (WGTS) can detect delayed colonic transit (CT), different types of CT delays, and assess upper GI tract transit.

AIM

To delineate the frequency of different types of CT patterns in patients with chronic constipation (CC), determine the relationship between these CT patterns and upper GI tract transit abnormalities, and assess how symptoms relate to different colonic transit patterns.

METHODS

Retrospective review of patients who had WGTS for CC. Patients completed a modified PAGI-SYM questionnaire to assess symptoms. Patients ingested a standard solid (Tc-99m egg sandwich)-liquid (In-111 water) meal to assess solid meal gastric emptying (GE), liquid GE, small bowel transit (SBT), and geometric center of colonic activity at 24, 48, and 72h.

RESULTS

One hundred and eighty six patients underwent WGTS. Main symptoms were constipation (41%), nausea (24%), and bloating (22%). CT assessment showed 32% of patients had normal transit, 31% colonic inertia (CI), 28% functional rectosigmoid obstruction (FRS0), and 9% generalized slow colonic transit (GSCT). GE was delayed in 36%; more commonly in CI and FRSO. SBT was delayed in 19%; more commonly in GSCT and CI. Patients with CI had less bowel movements per week whereas patients with normal CT had more bm/week.

CONCLUSIONS

In this series of patients with symptomatic constipation, WGTS assessment showed delayed colonic transit in 68% of patients, with 31% having colonic inertia, 28% a functional rectosigmoid obstruction pattern, and 9% generalized delay in colonic transit. Abnormalities in GE and SBT were present in 36 and 19%. WGTS is helpful to document delayed colonic transit (CT), assess the pattern of the delay in CT, and determine if there are upper GI transit abnormalities.

Gastrointestinal Dysmotility, Autonomic Function and Small Intestinal Bacterial Overgrowth Among People with Well-Controlled HIV

Introduction

Gastrointestinal dysfunction, including microbiome changes and increased translocation across a compromised gastrointestinal barrier plays a role in the chronic inflammation experienced by people with HIV (PWH). It is unknown whether autonomic neuropathy (AN) may contribute to these mechanisms by altering gastrointestinal motility.

Methods

This is a cross-sectional study of 100 PWH and 89 controls. All participants underwent assessment of gastrointestinal transit times using a wireless motility capsule (WMC). All PWH and a subset of controls also underwent: a standardized battery of autonomic function tests summarized as the Modified Composite Autonomic Severity Score (MCASS) and its adrenergic, cardiovagal and sudomotor sub-scores, breath testing for small intestinal bacterial overgrowth (SIBO), and the Patient Assessment of Upper Gastrointestinal Disorders Symptoms (PAGI-SYM) and Composite Autonomic Symptom Score 31 (COMPASS-31) questionnaires.

Results

PWH displayed shorter gastric emptying times (GET) and longer small bowel and colonic transit times (SBTT, CTT) compared to controls. Among PWH, GET was associated with PAGI-SYM score. The MCASS and its sudomotor sub-score (reflecting peripheral sympathetic function) were associated with SBTT but not GET or CTT. PWH with prolonged SBTT (>6h) were more likely to have SIBO.

Conclusion

Gastrointestinal motility is altered in PWH. This study provides preliminary evidence that changes in autonomic function may influence SBTT in PWH and that prolonged SBTT may contribute to the development of SIBO. Future studies are needed to more fully elucidate the pathophysiologic links between HIV-associated AN, altered gastrointestinal motility, the gastrointestinal microbiome, chronic inflammation, and resulting morbidity and mortality among PWH.

The importance of food quality, gut motility, and microbiome in SIBO development and treatment

The prevalence of small intestinal bacterial overgrowth (SIBO) is rising worldwide, particularly in nations with high rates of urbanization. Irritable bowel syndrome, inflammatory bowel illnesses, and nonspecific dysmotility are strongly linked to SIBO. Moreover, repeated antibiotic therapy promotes microorganisms' overgrowth through the development of antibiotic resistance. The primary cause of excessive fermentation in the small intestine is a malfunctioning gastrointestinal motor complex, which results in the gut's longer retention of food residues. There are anatomical and physiological factors affecting the functioning of the myoelectric motor complex. Except for them, diet conditions the activity of gastrointestinal transit. Indisputably, the Western type of nutrition is unfavorable. Some food components have greater importance in the functioning of the gastrointestinal motor complex than others. Tryptophan, an essential amino acid and precursor of the serotonin hormone, accelerates intestinal transit, and gastric emptying, similarly to fiber and polyphenols. Additionally, the effect of food on the microbiome is important, and diet should prevent bacterial overgrowth and exhibit antimicrobial effects against pathogens. Therefore, knowledge about proper nutrition is essential to prevent the development and recurrence of SIBO. Since the scientific world was unsure whether there was a long-term or potential solution for SIBO until quite recently, research on a number of the topics included in the article should be performed. The article aimed to summarize current knowledge about proper nutrition after SIBO eradication and the prevention of recurrent bacterial overgrowth. Moreover, a connection was found between diet, gut dysmotility, and SIBO.

The Postbiotic Properties of Butyrate in the Modulation of the Gut Microbiota: The Potential of Its Combination with Polyphenols and Dietary Fibers

The gut microbiota is a diverse bacterial community consisting of approximately 2000 species, predominantly from five phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia. The microbiota's bacterial species create distinct compounds that impact the host's health, including well-known short-chain fatty acids. These are produced through the breakdown of dietary fibers and fermentation of undigested carbohydrates by the intestinal microbiota. The main short-chain fatty acids consist of acetate, propionate, and butyrate. The concentration of butyrate in mammalian intestines varies depending on the diet. Its main functions are use as an energy source, cell differentiation, reduction in the inflammatory process in the intestine, and defense against oxidative stress. It also plays an epigenetic role in histone deacetylases, thus helping to reduce the risk of colon cancer. Finally, butyrate affects the gut-brain axis by crossing the brain-blood barrier, making it crucial to determine the right concentrations for both local and peripheral effects. In recent years, there has been a significant amount of attention given to the role of dietary polyphenols and fibers in promoting human health. Polyphenols and dietary fibers both play crucial roles in protecting human health and can produce butyrate through gut microbiota fermentation. This paper aims to summarize information on the key summits related to the negative correlation between intestinal microbiota diversity and chronic diseases to guide future research on determining the specific activity of butyrate from polyphenols and dietary fibers that can carry out these vital functions.

Fecal Coprococcus, hidden behind abdominal symptoms in patients with small intestinal bacterial overgrowth

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is the presence of an abnormally excessive amount of bacterial colonization in the small bowel. Hydrogen and methane breath test has been widely applied as a non-invasive method for SIBO. However, the positive breath test representative of bacterial overgrowth could also be detected in asymptomatic individuals.

METHODS

To explore the relationship between clinical symptoms and gut dysbiosis, and find potential fecal biomarkers for SIBO, we compared the microbial profiles between SIBO subjects with positive breath test but without abdominal symptoms (PBT) and healthy controls (HC) using 16S rRNA amplicon sequencing.

RESULTS

Fecal samples were collected from 63 SIBO who complained of diarrhea, distension, constipation, or abdominal pain, 36 PBT, and 55 HC. For alpha diversity, the Shannon index of community diversity on the genus level showed a tendency for a slight increase in SIBO, while the Shannon index on the predicted function was significantly decreased in SIBO. On the genus level, significantly decreased Bacteroides, increased Coprococcus_2, and unique Butyrivibrio were observed in SIBO. There was a significant positive correlation between saccharolytic Coprococcus_2 and the severity of abdominal symptoms. Differently, the unique Veillonella in the PBT group was related to amino acid fermentation. Interestingly, the co-occurrence network density of PBT was larger than SIBO, which indicates a complicated interaction of genera. Coprococcus_2 showed one of the largest betweenness centrality in both SIBO and PBT microbiota networks. Pathway analysis based on the Kyoto Encyclopedia of Genes and Genome (KEGG) database reflected that one carbon pool by folate and multiple amino acid metabolism were significantly down in SIBO.

CONCLUSIONS

This study provides valuable insights into the fecal microbiota composition and predicted metabolic functional changes in patients with SIBO. Butyrivibrio and Coprococcus_2, both renowned for their role in carbohydrate fermenters and gas production, contributed significantly to the symptoms of the patients. Coprococcus's abundance hints at its use as a SIBO marker. Asymptomatic PBT individuals show a different microbiome, rich in Veillonella. PBT's complex microbial interactions might stabilize the intestinal ecosystem, but further study is needed due to the core microbiota similarities with SIBO. Predicted folate and amino acid metabolism reductions in SIBO merit additional validation.

Management of Gastrointestinal Symptoms in Parkinson's Disease: A Comprehensive Review of Clinical Presentation, Workup, and Treatment

Gastrointestinal symptoms in Parkinson's disease (PD) are among the most prevalent and debilitating of complications and present unique diagnostic and management challenges. Patients with PD commonly experience dysphagia, nausea, bloating, and constipation related to pathologic involvement of the enteric nervous system. In turn, gastrointestinal complications may impact motor fluctuations and the efficacy of levodopa therapy. This review will explore the common gastrointestinal manifestations of PD with an emphasis on clinical presentation, workup, and treatment strategies.

Small intestinal bacterial overgrowth: current update

PURPOSE OF REVIEW

This article aims to provide an up-to-date review of small intestinal bacterial overgrowth (SIBO), including etiology and risk factors, clinical manifestations, diagnostic evaluation for suspected SIBO, and therapeutic options.

RECENT FINDINGS

Recent advances in breath testing, capsule and urine-based testing have opened new avenues and improved diagnostic yield of SIBO. Nonantibiotic-based treatment strategies have shown promising results in initial trials.

SUMMARY

Small intestinal bacterial overgrowth (SIBO) is a condition defined by the excess bacteria or changes in bacterial composition of the small intestine. These are associated with various gastrointestinal (GI) symptoms such as bloating, abdominal distension, diarrhea, nutrient deficiencies, and even frank weight loss. Small bowel jejunal aspirate of >10 5 CFU/ml has traditionally been considered the gold standard for diagnosis. Glucose and lactulose breath testing have become more common in clinical practice as they are noninvasive, easily accessible, and have lower cost. Treatment focuses on the eradication of excess bacteria in the small bowel and is traditionally done with the use of oral antibiotics. Other emerging therapies may include probiotics, diet manipulation, and prokinetic agents.

Maternal constipation is associated with allergic rhinitis in the offspring: A nationwide retrospective cohort study

Allergic rhinitis (AR) is a common atopic disease worldwide, and it was found that babies with constipation in their early life might have an increased risk of atopic diseases, including AR. Furthermore, recent studies also indicate that the maternal gut microbiota may influence babies. Thus, we extended the definition of early life in utero and evaluated the association between maternal constipation and the risk of AR in their babies. Using the Longitudinal Health Insurance Database, a subset of Taiwan's National Health Insurance Research Database, we identified 102,820 constipated mothers and 102,820 matched controls between 2005 and 2015. Propensity score analysis was used to match birth year, child sex, birth weight, gestational age, mode of delivery, maternal comorbidities, and children antibiotics taken. Multiple Cox regression and subgroup analyzes were conducted to estimate the adjusted hazard ratio of childhood AR. The incidence of childhood AR was 83.47 per 1,000 person-years in constipated mothers. Adjusting children's sex, birth weight, gestational age, mode of delivery, maternal comorbidities, and children antibiotic use, the results showed that the children whose mothers had constipation had a 1.20-fold risk of AR compared to children of mothers without constipation. Maternal constipation was associated with an increased risk of AR. Therefore, it is important to pay close attention to pregnant mothers with constipation.

Pharmacologic treatment of gastroparesis: What is (still) on the horizon?

Gastroparesis is a neuromuscular disorder of the upper gastrointestinal tract. Patients typically complain about early satiety, postprandial fullness, nausea and vomiting. Etiology is multifactorial. Treatment strategies include nutritional support, pharmacologic agents or surgery for refractory cases. Metoclopramide is the first and only FDA approved pharmacologic agent for (diabetic) Gastroparesis. A couple of compounds are currently in clinical testing. Some beacons of hope have failed recently, however. Here we present an update on possible future treatment options.

Epidemiology of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth (SIBO) is defined as an increase in the bacterial content of the small intestine above normal values. The presence of SIBO is detected in 33.8% of patients with gastroenterological complaints who underwent a breath test, and is significantly associated with smoking, bloating, abdominal pain, and anemia. Proton pump inhibitor therapy is a significant risk factor for SIBO. The risk of SIBO increases with age and does not depend on gender or race. SIBO complicates the course of a number of diseases and may be of pathogenetic significance in the development of their symptoms. SIBO is significantly associated with functional dyspepsia, irritable bowel syndrome, functional abdominal bloating, functional constipation, functional diarrhea, short bowel syndrome, chronic intestinal pseudo-obstruction, lactase deficiency, diverticular and celiac diseases, ulcerative colitis, Crohn’s disease, cirrhosis, metabolic-associated fatty liver disease (MAFLD), primary biliary cholangitis, gastroparesis, pancreatitis, cystic fibrosis, gallstone disease, diabetes, hypothyroidism, hyperlipidemia, acromegaly, multiple sclerosis, autism, Parkinson’s disease, systemic sclerosis, spondylarthropathy, fibromyalgia, asthma, heart failure, and other diseases. The development of SIBO is often associated with a slowdown in orocecal transit time that decreases the normal clearance of bacteria from the small intestine. The slowdown of this transit may be due to motor dysfunction of the intestine in diseases of the gut, autonomic diabetic polyneuropathy, and portal hypertension, or a decrease in the motor-stimulating influence of thyroid hormones. In a number of diseases, including cirrhosis, MAFLD, diabetes, and pancreatitis, an association was found between disease severity and the presence of SIBO. Further work on the effect of SIBO eradication on the condition and prognosis of patients with various diseases is required.

Gastrointestinal Tract Considerations: Part II: How Should a Rheumatologist Best Manage Common Lower Gastrointestinal Tract Complaints in Systemic Sclerosis?

Lower gastrointestinal (GI) symptoms are a frequently encountered problem for clinicians managing patients with systemic sclerosis. The current management practices are focused on the treatment of symptoms with little information available on how to use GI investigations in daily practice. This review demonstrates how to integrate the objective assessment of common lower GI symptoms into clinical care with the aim of guiding clinical decision making. Understanding the type of abnormal GI function that is affecting a patient and determining which parts of the gut are impacted can help clinicians to target therapy more precisely.

The Role of Small Intestinal Bacterial Overgrowth in Obesity and Its Related Diseases

Obesity has become a major public health problem worldwide and its occurrence is increasing globally. Obesity has also been shown to be involved in the occurrence and development of many diseases and pathological conditions, such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus (T2DM), insulin resistance (IR). In recent years, gut microbiota has received extensive attention as an important regulatory part involved in host diseases and health status. A growing body of evidence suggests that gut microbiota dysbiosis has a significant adverse effect on the host. Small intestinal bacterial overgrowth (SIBO), a type of intestinal microbial dysbiosis, has been gradually revealed to be associated with obesity and its related diseases. The presence of SIBO may lead to the destruction of intestinal barrier integrity, increased intestinal permeability, increased endotoxin levels, activation of inflammatory responses, and translocation of bacteria from the colon to the small intestine. However, the causal relationship between SIBO and obesity and the specific mechanisms have not been well elucidated. This review discusses the cross-talk between SIBO and obesity and its related diseases, and expounds its potential mechanisms and interventions, which may help to discover new therapeutic targets for obesity and its related diseases and develop treatment options.

Impact of Objective Colonic and Whole Gut Motility Data as Measured by Wireless Motility Capsule on Outcomes of Antireflux Surgery

BACKGROUND

Studies show higher rates of dissatisfaction with antireflux surgery (ARS) outcomes in patients with chronic constipation. This suggests a relationship between colonic dysmotility and suboptimal surgical outcome. However, due to limitations in technology, there is no objective data available examining this relationship. The wireless motility capsule (WMC) is a novel technology consisting of an ingestible capsule equipped with pH, temperature, and pressure sensors, which provide information regarding regional and whole gut transit times, pH and motility. The aim of this study was to assess the impact of objective regional and whole gut motility data on the outcomes of ARS.

STUDY DESIGN

This was a retrospective review of patients who underwent WMC testing before ARS. Transit times, motility, and pH data obtained from different gastrointestinal tract regions were used in analysis to determine factors that impact surgical outcome. A favorable outcome was defined as complete resolution of the predominant reflux symptom and freedom from antisecretory medications.

RESULTS

The final study population consisted of 48 patients (fundoplication [n = 29] and magnetic sphincter augmentation [n = 19]). Of those patients, 87.5% were females and the mean age ± SD was 51.8 ± 14.5 years. At follow-up (mean ± SD, 16.8 ± 13.2 months), 87.5% of all patients achieved favorable outcomes. Patients with unfavorable outcomes had longer mean whole gut transit times (92.0 hours vs 55.7 hours; p = 0.024) and colonic transit times (78.6 hours vs 47.3 hours; p = 0.028), higher mean peak colonic pH (8.8 vs 8.15; p = 0.009), and higher mean antral motility indexes (310 vs 90.1; p = 0.050).

CONCLUSIONS

This is the first study to demonstrate that objective colonic dysmotility leads to suboptimal outcomes after ARS. WMC testing can assist with preoperative risk assessment and counseling for patients seeking ARS.

Advancing human gut microbiota research by considering gut transit time

Accumulating evidence indicates that gut transit time is a key factor in shaping the gut microbiota composition and activity, which are linked to human health. Both population-wide and small-scale studies have identified transit time as a top covariate contributing to the large interindividual variation in the faecal microbiota composition. Despite this, transit time is still rarely being considered in the field of the human gut microbiome. Here, we review the latest research describing how and why whole gut and segmental transit times vary substantially between and within individuals, and how variations in gut transit time impact the gut microbiota composition, diversity and metabolism. Furthermore, we discuss the mechanisms by which the gut microbiota may causally affect gut motility. We argue that by taking into account the interindividual and intraindividual differences in gut transit time, we can advance our understanding of diet-microbiota interactions and disease-related microbiome signatures, since these may often be confounded by transient or persistent alterations in transit time. Altogether, a better understanding of the complex, bidirectional interactions between the gut microbiota and transit time is required to better understand gut microbiome variations in health and disease.

Aetiology, diagnosis and management of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth is a small bowel disorder characterised by excessive amounts of bacteria populating the small intestine leading to symptoms of abdominal pain, bloating and change in bowel habit. This creates some degree of diagnostic uncertainty due to the overlap of these symptoms with numerous other gastrointestinal conditions. Quantitative culture of jejunal aspirates is the gold standard diagnostic test but has largely been replaced by glucose and lactulose breath tests due to their relative ease and accessibility. The approach to treatment centres around reducing bacterial numbers through antibiotic therapy and managing any predisposing factors. Further research is required in order to define the optimum antibiotic choice and duration of therapy as well as the potential diagnostic utility of home breath testing and capsule-based technology.

Assessment of Yeasts as Potential Probiotics: A Review of Gastrointestinal Tract Conditions and Investigation Methods

Probiotics are microorganisms (including bacteria, yeasts and moulds) that confer various health benefits to the host, when consumed in sufficient amounts. Food products containing probiotics, called functional foods, have several health-promoting and therapeutic benefits. The significant role of yeasts in producing functional foods with promoted health benefits is well documented. Hence, there is considerable interest in isolating new yeasts as potential probiotics. Survival in the gastrointestinal tract (GIT), salt tolerance and adherence to epithelial cells are preconditions to classify such microorganisms as probiotics. Clear understanding of how yeasts can overcome GIT and salt stresses and the conditions that support yeasts to grow under such conditions is paramount for identifying, characterising and selecting probiotic yeast strains. This study elaborated the adaptations and mechanisms underlying the survival of probiotic yeasts under GIT and salt stresses. This study also discussed the capability of yeasts to adhere to epithelial cells (hydrophobicity and autoaggregation) and shed light on in vitro methods used to assess the probiotic characteristics of newly isolated yeasts.

DIAGNOSIS AND MANAGEMENT OF CHRONIC IDIOPATHIC CONSTIPATION: A NARRATIVE REVIEW FROM A BRAZILIAN EXPERT TASK FORCE

ABSTRACT Background Chronic idiopathic constipation (CIC) is a condition that widely affects the global population, represents relevant healthcare resource utilization and costs, and impacts the individual’s well-being. Objective To review the consensus of expert societies and published guidelines on the diagnosis and treatment of CIC in adults, seeking to assist reasoning and decision-making for medical management of patients with CIC and provide a practical reference material. Methods A Brazilian medical task force searched the scientific literature in the following electronic databases: MEDLINE/PubMed, SciELO, EMBASE and Cochrane, using the following descriptors: chronic constipation, diagnosis, management of chronic constipation. In addition, a review of articles on the mechanism of action, safety, and efficacy of therapeutic options available in Brazil was carried out. Results The diagnostic approach and the understanding of the pathophysiology present in CIC are essential items to indicate the appropriate therapy and to understand the ecosystem of the patient’s needs. Conclusion CIC is a common condition in adults, occurring more frequently in the elderly and in women. Proper management is defined by detailed medical history and physical examination, together with appropriate therapeutics, regardless pharmacological or not, and depending on the best moment of indication. This way, the impact on quality of life is also optimized.

Asian-Pacific consensus on small intestinal bacterial overgrowth in gastrointestinal disorders: An initiative of the Indian Neurogastroenterology and Motility Association

In the clinical setting, small intestinal bacterial overgrowth (SIBO) is a frequent, but under-diagnosed entity. SIBO is linked to various gastrointestinal (GI) and non-GI disorders with potentially significant morbidity. The optimal management of SIBO is undefined while there is a lack of published consensus guidelines. Against this background, under the auspices of the Indian Neurogastroenterology and Motility Association (INMA), formerly known as the Indian Motility and Functional Diseases Association (IMFDA), experts from the Asian-Pacific region with extensive research and clinical experience in the field of gut dysbiosis including SIBO developed this evidence-based practice guideline for the management of SIBO utilizing a modified Delphi process based upon 37 consensus statements, involving an electronic voting process as well as face-to-face meetings and review of relevant supporting literature. These statements include 6 statements on definition and epidemiology; 11 on etiopathogenesis and pathophysiology; 5 on clinical manifestations, differential diagnosis, and predictors; and 15 on investigations and treatment. When the proportion of those who voted either to accept completely or with minor reservations was 80% or higher, the statement was regarded as accepted. The members of the consensus team consider that this guideline would be valuable to inform clinical practice, teaching, and research on SIBO in the Asian-Pacific region as well as in other countries.

Small intestinal bacterial overgrowth and orocecal transit time in patients of nonalcoholic fatty liver disease

OBJECTIVE

The aim of the present study is to explore the frequency of small intestinal bacterial overgrowth (SIBO) and orocecal transit time (OCTT) in patients with nonalcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

103 patients with NAFLD and 49 healthy controls were enrolled. Clinical indicators such as BMI, liver function, blood lipids, homeostasis model assessment-insulin resistance (HOMA-IR), serum endotoxin of NAFLD patients were collected and examined. FibroTouch was used to detect the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). SIBO and OCTT were measured by the lactulose hydrogen breath test.

RESULTS

The incidence of SIBO in NAFLD patients (58.3%) was significantly higher than that in healthy controls (26.5%). The level of serum endotoxin in NAFLD patients was higher than that in healthy controls. The levels of CAP, LSM, serum endotoxin, alanine transaminase, asperate aminotransferase and HOMA-IR in SBIO-positive NAFLD patients were higher than those in SIBO-negative patients. There was no significant difference in glutamyl transpeptidase triglyceride, low density lipoprotein and BMI between the two groups. OCTT in NAFLD patients was longer than that in healthy controls. It was also observed that OCTT in SIBO-positive NAFLD patients was significantly delayed compared with SIBO-negative NAFLD patients.

CONCLUSIONS

Patients with NAFLD exhibit the increased incidence rate of SIBO and prolonged OCTT; SIBO in NAFLD patients maybe a contributing factor to the elevated transaminase, hepatic steatosis, progression of liver fibrosis and prolonged OCTT.

Quantitative sequencing clarifies the role of disruptor taxa, oral microbiota, and strict anaerobes in the human small-intestine microbiome

BACKGROUND

Upper gastrointestinal (GI) disorders and abdominal pain afflict between 12 and 30% of the worldwide population and research suggests these conditions are linked to the gut microbiome. Although large-intestine microbiota have been linked to several GI diseases, the microbiota of the human small intestine and its relation to human disease has been understudied. The small intestine is the major site for immune surveillance in the gut, and compared with the large intestine, it has greater than 100 times the surface area and a thinner and more permeable mucus layer.

RESULTS

Using quantitative sequencing, we evaluated total and taxon-specific absolute microbial loads from 250 duodenal-aspirate samples and 21 paired duodenum-saliva samples from participants in the REIMAGINE study. Log-transformed total microbial loads spanned 5 logs and were normally distributed. Paired saliva-duodenum samples suggested potential transmission of oral microbes to the duodenum, including organisms from the HACEK group. Several taxa, including Klebsiella, Escherichia, Enterococcus, and Clostridium, seemed to displace strict anaerobes common in the duodenum, so we refer to these taxa as disruptors. Disruptor taxa were enriched in samples with high total microbial loads and in individuals with small intestinal bacterial overgrowth (SIBO). Absolute loads of disruptors were associated with more severe GI symptoms, highlighting the value of absolute taxon quantification when studying small-intestine health and function.

CONCLUSION

This study provides the largest dataset of the absolute abundance of microbiota from the human duodenum to date. The results reveal a clear relationship between the oral microbiota and the duodenal microbiota and suggest an association between the absolute abundance of disruptor taxa, SIBO, and the prevalence of severe GI symptoms. Video Abstract.

Gut-associated cGMP mediates colitis and dysbiosis in a mouse model of an activating mutation in GUCY2C

Activating mutations in receptor guanylyl cyclase C (GC-C), the target of gastrointestinal peptide hormones guanylin and uroguanylin, and bacterial heat-stable enterotoxins cause early-onset diarrhea and chronic inflammatory bowel disease (IBD). GC-C regulates ion and fluid secretion in the gut via cGMP production and activation of cGMP-dependent protein kinase II. We characterize a novel mouse model harboring an activating mutation in Gucy2c equivalent to that seen in an affected Norwegian family. Mutant mice demonstrated elevated intestinal cGMP levels and enhanced fecal water and sodium content. Basal and linaclotide-mediated small intestinal transit was higher in mutant mice, and they were more susceptible to DSS-induced colitis. Fecal microbiome and gene expression analyses of colonic tissue revealed dysbiosis, up-regulation of IFN-stimulated genes, and misregulation of genes associated with human IBD and animal models of colitis. This novel mouse model thus provides molecular insights into the multiple roles of intestinal epithelial cell cGMP, which culminate in dysbiosis and the induction of inflammation in the gut.

Progress in understanding of relationship between gut microbiota and gastrointestinal motility

Gastrointestinal motility disorders are a group of common clinical disorders in which abnormal gastrointestinal motility is the major pathogenesis, including irritable bowel syndrome, functional dyspepsia, and diabetic gastroparesis. With the rapid development of microbial sequencing technology in the past 10 years, the understanding of the gut microbiota has greatly improved, and it is generally found that patients with gastrointestinal motility diseases have gut microbiota disorders. Some progress has been made on the correlation between gut microbiota and gastrointestinal motility. This review aims to elucidate the relationship between gut microbiota and gastrointestinal motility and the mechanism of their interaction.

Approach to the adult patient with chronic diarrhea: A literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Potential Applications of Chitosan-Based Nanomaterials to Surpass the Gastrointestinal Physiological Obstacles and Enhance the Intestinal Drug Absorption

The small intestine provides the major site for the absorption of numerous orally administered drugs. However, before reaching to the systemic circulation to exert beneficial pharmacological activities, the oral drug delivery is hindered by poor absorption/metabolic instability of the drugs in gastrointestinal (GI) tract and the presence of the mucus layer overlying intestinal epithelium. Therefore, a polymeric drug delivery system has emerged as a robust approach to enhance oral drug bioavailability and intestinal drug absorption. Chitosan, a cationic polymer derived from chitin, and its derivatives have received remarkable attention to serve as a promising drug carrier, chiefly owing to their versatile, biocompatible, biodegradable, and non-toxic properties. Several types of chitosan-based drug delivery systems have been developed, including chemical modification, conjugates, capsules, and hybrids. They have been shown to be effective in improving intestinal assimilation of several types of drugs, e.g., antidiabetic, anticancer, antimicrobial, and anti-inflammatory drugs. In this review, the physiological challenges affecting intestinal drug absorption and the effects of chitosan on those parameters impacting on oral bioavailability are summarized. More appreciably, types of chitosan-based nanomaterials enhancing intestinal drug absorption and their mechanisms, as well as potential applications in diabetes, cancers, infections, and inflammation, are highlighted. The future perspective of chitosan applications is also discussed.

Approach to the adult patient with chronic diarrhea: a literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Recent Advances in the Management of Severe Gastrointestinal Dysmotility

Severe gastrointestinal motility disorders with small bowel involvement continue to pose a major clinical challenge to clinicians, particularly because of the limitations of diagnostic tests and the lack of efficacious treatment options. In this article, we review current understanding and the utility of diagnostic modalities and therapeutic approaches, and describe how their limitations may potentially exacerbate prolonged suffering with debilitating symptoms, diagnostic delays, the risk of iatrogenic harm and increased healthcare utilisation in this group of patients. Moreover, observations from intestinal failure units worldwide suggest that this problem could be set to increase in the future, with reported trends of increasing numbers of patients presenting with nutritional consequences. Unfortunately, until recently, there has been a lack of consensus recommendations and guidance to support clinicians with their management approach. The aim of this narrative review is to summarise recent developments in this field following publication of an international census of experts, and subsequent clinical guidelines, which have emphasized the importance of holistic, multidisciplinary care. This is particularly important in achieving good clinical outcomes and ensuring the appropriate use of artificial nutritional support, in order to prevent iatrogenic harm. We discuss how these recent developments may impact clinical practice by supporting the development of specialised clinical services to deliver optimal care, and highlight areas where further research is needed.

Delayed Gastric Emptying Is Not Associated with a Microbiological Diagnosis of Small Intestinal Bacterial Overgrowth

BACKGROUND

Clinical symptoms of patients with small intestinal bacterial overgrowth (SIBO) may overlap with symptoms of gastroparesis. Prior studies suggest delayed small intestinal transit is associated with SIBO, but have not shown an association between delayed gastric emptying and SIBO. However, these studies have generally relied on the indirect method of breath testing to diagnose SIBO.

AIMS

The aim of this study was to examine the association between a microbiological diagnosis of SIBO and delayed gastric emptying by scintigraphy.

METHODS

In a single-center retrospective study of previous research participants who presented for small bowel enteroscopy for diagnostic evaluation of SIBO, we identified 73 participants who underwent gastric emptying study by scintigraphy. A microbiological diagnosis of SIBO was made in patients based on culture results of jejunal aspirates. Clinical symptoms were assessed using the total gastroparesis cardinal symptom index (GCSI) score. We compared delayed gastric emptying, 2- and 4-h gastric retention, and gastroparesis symptoms between patients with and without a microbiological diagnosis of SIBO.

KEY RESULTS

Among 29 participants with SIBO and 44 without SIBO, 33 (45%) had evidence of delayed gastric emptying. There was no significant association between a microbiological diagnosis of SIBO and delayed gastric emptying by scintigraphy. Percent retained at 2 and 4 h, and total GCSI scores did not differ significantly between those with and without SIBO.

CONCLUSIONS

Although delayed gastric emptying is common in patients with suspected SIBO, gastric emptying is not associated with a microbiological diagnosis of SIBO.

Managing gastrointestinal complications in patients with systemic sclerosis

Objective

We sought to critically evaluate the literature published over the past 3 years on the management of gastrointestinal complications in systemic sclerosis (SSc). We emphasize interesting and important new findings to bring the reader up-to-date. We also discuss controversial discoveries and hypotheses currently of interest.

Methods

We conducted a literature search on PubMed over the last 3 years using the key words "systemic sclerosis," "gastrointestinal," "scleroderma," and "treatment." We also screened clinicaltrials.gov for ongoing trials relevant to the gastrointestinal complications of SSc. Reference lists from recent reviews on the management of gastrointestinal complications of SSc to identify articles that might have been missed in the initial search.

Results

103 publications and ongoing clinical trials were identified. We eliminated all case reports and review articles. Ultimately we had 58 articles remaining and we prioritized what we found to be the strongest and/or novel findings to discuss in this review.

Conclusions

Advances in the management of gastrointestinal disease in SSc continue to evolve. The application of novel therapies and the repurposing of existing therapies for the management of gastrointestinal involvement are shaping the therapeutic arsenal so that we can more effectively manage these complex patients.

Small Intestinal Bacterial Overgrowth: Clinical Presentation in Patients with Roux-en-Y Gastric Bypass

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is defined by an increased number of bacteria measured via exhaled hydrogen and/or methane gas following the ingestion of glucose. This condition is prevalent following abdominal surgery, including Roux-en-Y gastric bypass (RYGB), and associated with a variety of non-specific abdominal symptoms, often requiring an extensive diagnostic work-up.

AIM

To assess the frequency that individuals with RYGB anatomy are diagnosed with SIBO and if they are more likely to report specific gastrointestinal (GI) symptoms compared to individuals with native anatomy.

METHODS

This large matched cohort study evaluated patients with GI symptoms who underwent a glucose breath test (GBT) for SIBO evaluation, utilizing 1:2 matching between RYGB and native anatomy. Patients with positive GBT were included in univariate and multivariate analyses to distinguish the presence of ten specific GI symptoms between RYGB and native anatomy.

RESULTS

A total of 17,973 patients were included, where 271 patients with RYGB were matched to 573 patients with native anatomy that underwent GBT. Patients with RYGB anatomy and a positive GBT (199; 73.4%) as compared to those with native anatomy and a positive GBT (209; 36%) more often reported nausea, vomiting, bloating, and diarrhea. There were no differences between the two groups in the report of heartburn, regurgitation, chest pain, gas, or constipation.

CONCLUSIONS

SIBO is common in patients with RYGB and more commonly report nausea, vomiting, bloating, and diarrhea. The results of this study suggest that the report of these symptoms in RYGB should prompt early evaluation for SIBO.

The Gut Microbiome and Individual-Specific Responses to Diet

Nutritional content and timing are increasingly appreciated to constitute important human variables collectively impacting all aspects of human physiology and disease. However, person-specific mechanisms driving nutritional impacts on the human host remain incompletely understood, while current dietary recommendations remain empirical and nonpersonalized. Precision nutrition aims to harness individualized bodies of data, including the human gut microbiome, in predicting person-specific physiological responses (such as glycemic responses) to food. With these advances notwithstanding, many unknowns remain, including the long-term efficacy of such interventions in delaying or reversing human metabolic disease, mechanisms driving these dietary effects, and the extent of the contribution of the gut microbiome to these processes. We summarize these conceptual advances, while highlighting challenges and means of addressing them in the next decade of study of precision medicine, toward generation of insights that may help to evolve precision nutrition as an effective future tool in a variety of "multifactorial" human disorders.

Bidirectional interaction between intestinal microbiome and cancer: opportunities for therapeutic interventions

Gut microbiota composition influences the balance between human health and disease. Increasing evidence suggests the involvement of microbial factors in regulating cancer development, progression, and therapeutic response. Distinct microbial species have been implicated in modulating gut environment and architecture that affects cancer therapy outcomes. While some microbial species offer enhanced cancer therapy response, others diminish cancer treatment efficacy. In addition, use of antibiotics, often to minimize infection risks in cancer, causes intestinal dysbiosis and proves detrimental. In this review we discuss the role of gut microbiota in cancer development and therapy. We also provide insights into future strategies to manipulate the microbiome and gut epithelial barrier to augment therapeutic responses while minimizing toxicity or infection risks.

Ileocecal valve syndrome and vitamin b12 deficiency after surgery: a multicentric prospective study

Patients undergoing colon resection are often concerned about their functional outcomes after surgery. The primary aim of this prospective, multicentric study was to assess the intestinal activity and health-related quality-of-life (HRQL) after ileocecal valve removal. The secondary aim was to evaluate any vitamin B12 deficiency. The study included patients undergoing right colectomy, extended right colectomy and ileocecal resection for either neoplastic or benign disease. Selected items of GIQLI and EORTC QLQ-CR29 questionnaires were used to investigate intestinal activity and HRQL before and after surgery. Blood samples for vitamin B12 level were collected before and during the follow-up period. The empirical rule effect size (ERES) method was used to explain the clinical effect of statistical results. Linear mixed effect (LME) model for longitudinal data was applied to detect the most important parameters affecting the total score. A total of 158 patients were considered. Applying the ERES method, the analysis of both questionnaires showed clinically and statistically significant improvement of HRQL at the end of the follow-up period. Applying the LME model, worsening of HRQL was correlated with female gender and ileum length when using GIQLI questionnaire, and with female gender, open approach, and advanced cancer stage when using the EORTC QLQ-CR29 questionnaire. No significant deficiency in vitamin B12 levels was observed regardless of the length of surgical specimen. In our series, no deterioration of HRQL and no vitamin B12 deficiency were found during the follow-up period. Nevertheless, warning patients about potential changes in bowel habits is mandatory. In our series, no deterioration of HRQL and no vitamin B12 deficiency were found during the follow-up period. Nevertheless, warning patients about potential changes in bowel habits is mandatory.

Small intestinal bacterial overgrowth and chronic pancreatitis

Chronic pancreatitis (CP) is defined as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental, and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress. Because of its persistent symptoms, CP often requires lifelong treatment, which seriously affects the quality of life of patients. Small intestinal bacterial overgrowth (SIBO) is an abnormal increase in the number of bacteria and/or changes in the bacterial flora, which symptoms are similar to those of CP. In recent years, a growing number of studies have shown that SIBO may be both an important manifestation of CP and a cause of aggravating intestinal symptoms and malnutrition in patients with CP. Anti-bacterial therapy for SIBO may improve the symptoms and quality of life of patients with CP. In this paper, we discuss the relationship between SIBO and CP.

Validation of Diagnostic and Performance Characteristics of the Wireless Motility Capsule in Patients With Suspected Gastroparesis

BACKGROUND & AIMS

It is a challenge to make a diagnosis of gastroparesis. There is good agreement in results from wireless motility capsule (WMC) analysis and gastric emptying scintigraphy (GES), but the diagnostic yield of WMC is unclear and the accuracy of this method has not been validated. We compared the performance characteristics of WMC vs GES in assessing gastric emptying in patients with suspected gastroparesis.

METHODS

We performed a prospective study of 167 subjects with gastroparesis (53 with diabetes and 114 without) at 10 centers, from 2013 through 2016. Subjects were assessed simultaneously by GES and with a WMC to measure gastric emptying and regional transit. Delayed gastric emptying by GES was defined as more than 10% meal retention at 4 hrs whereas delayed gastric emptying by WMC was defined as more than 5 hrs for passage of the capsule into the duodenum; a severe delay in gastric emptying was defined as a gastric emptying time of more than 12 hrs by WMC or more than 35% retention at 4 hrs by GES. Rapid gastric emptying was defined as less than 38% meal retention at 1 hr based on by GES or gastric emptying times less than 1:45 hrs by WMC. We compared diagnostic and performance characteristics of GES vs WMC.

RESULTS

Delayed gastric emptying was detected in a higher proportion of subjects by WMC (34.6%) than by GES (24.5%) (P=.009). Overall agreement in results between methods was 75.7% (kappa=0.42). In subjects without diabetes, the WMC detected a higher proportion of subjects with delayed gastric emptying (33.3%) than GES (17.1%) (P < .001). A higher proportion of subjects with diabetes had delayed gastric emptying detected by GES (41.7%) compared with non-diabetic subjects (17.1%) (P=.002). Severe delays in gastric emptying were observed in a higher proportion of subjects by WMC (13.8%) than by GES (6.9%) (P = .02). Rapid gastric emptying was detected in a higher proportion of subjects by GES (13.8%) than by WMC (3.3%) (P < .001). Regional and generalized transit abnormalities were observed in 61.8% subjects and only detected by WMC.

CONCLUSION

Although there is agreement in analysis of gastric emptying by GES vs WMC, WMC provides higher diagnostic yield than GES. WMC detects delayed gastric emptying more frequently than GES and identifies extra-gastric transit abnormalities. Diabetic vs non-diabetic subjects have different results from GES vs WMC. These findings could affect management of patients with suspected gastroparesis. ClinicalTrials.gov no: NCT02022826.

Are probiotics useful in the treatment of chronic idiopathic constipation in adults? A review of existing systematic reviews, meta-analyses, and recommendations

Chronic idiopathic constipation (CIC) has emerged as common problem for contemporary gastroenterology and is one of the most frequent complaints in primary care. Chronic idiopathic constipation significantly affects patients' quality of life and has an impact on global health and economy. Functional gastrointestinal disorders and bowel disorders, according to Rome IV criteria, result from inappropriate gut-brain interactions. The pathophysiology is complex and poorly understood, with evidence accumulating that gut microbiota can be implicated in the development and function of the enteric nervous system. Gut bacteria modulate gut barrier function, short chain fatty acid synthesis, and bile acid metabolism, factors which play roles in the gut peristalsis regulation. The high prevalence of CIC, with poor treatment outcomes, warrants searches for new forms of therapy, including probiotic therapies. Probiotics are often recommended by medical practitioners, but evidence-based utility in adults with CIC is uncertain. Recommendations/guidelines are often based on results from individual studies, rather than meta-analyses or umbrella reviews. Additionally, meta-analyses often indicate a group of probiotics rather than individual strains, and they create difficulty for physicians in making therapeutic choices. More CIC patient randomised clinical studies utilising well-defined strains, or combinations, are necessary.

The effect of pyridostigmine on small intestinal bacterial overgrowth (SIBO) and plasma inflammatory biomarkers in HIV-associated autonomic neuropathies

Small intestinal bacterial overgrowth (SIBO) is common among patients with HIV-associated autonomic neuropathies (HIV-AN) and may be associated with increased bacterial translocation and elevated plasma inflammatory biomarkers. Pyridostigmine is an acetylcholinesterase inhibitor which has been used to augment autonomic signaling. We sought preliminary evidence as to whether pyridostigmine could improve proximal gastrointestinal motility, reduce SIBO, reduce plasma sCD14 (a marker of macrophage activation and indirect measure of translocation), and reduce the inflammatory cytokines IL-6 and TNFα in patients with HIV-AN. Fifteen participants with well-controlled HIV, HIV-AN, and SIBO were treated with 8 weeks of pyridostigmine (30 mg PO TID). Glucose breath testing for SIBO, gastric emptying studies (GES) to assess motility, plasma sCD14, IL-6, and TNFα, and gastrointestinal autonomic symptoms were compared before and after treatment. Thirteen participants (87%) experienced an improvement in SIBO following pyridostigmine treatment; with an average improvement of 50% (p = 0.016). There was no change in gastrointestinal motility; however, only two participants met GES criteria for gastroparesis at baseline. TNFα and sCD14 levels declined by 12% (p = 0.004) and 19% (p = 0.015), respectively; there was no significant change in IL-6 or gastrointestinal symptoms. Pyridostigmine may ameliorate SIBO and reduce levels of sCD14 and TNFα in patients with HIV-AN. Larger placebo-controlled studies are needed to definitively delineate how HIV-AN affects gastrointestinal motility, SIBO, and systemic inflammation in HIV, and whether treatment improves clinical outcomes.

The Spectrum of Small Intestinal Bacterial Overgrowth (SIBO)

PURPOSE OF REVIEW

To critically review recent (past 3 years) literature on the definition, diagnosis, and management of small intestinal bacterial overgrowth (SIBO).

RECENT FINDINGS

While various series continue to illustrate the occurrence of SIBO in disease states where well-known risk factors for its occurrence are present (hypochlorhydria, disorders of intestinal structure or motor function, pancreatic insufficiency, and chronic liver disease, for example), the current challenge is in defining the limits of SIBO. Is SIBO truly common among those with "functional" gastrointestinal symptoms where there is no evidence of maldigestion or malabsorption; the original hallmarks of SIBO? Our attempts to address this question continue to be hampered by the limitations of our diagnostic tool kit. There is hope-the application of modern molecular techniques to the study of the small intestinal microbiome, together with some innovative sampling techniques, such as real-time intestinal gas sampling, may soon allow us to truly define the spectrum of SIBO. SIBO, once removed from its original confines as a cause of malabsorption syndrome, has proven to be an elusive and moving target. Only the most rigorous studies employing validated methodologies will finally corral this mysterious entity.

The Gut Microbiome in Adult and Pediatric Functional Gastrointestinal Disorders

The importance of gut microbiota in gastrointestinal (GI) physiology was well described, but our ability to study gut microbial ecosystems in their entirety was limited by culture-based methods prior to the sequencing revolution. The advent of high-throughput sequencing opened new avenues, allowing us to study gut microbial communities as an aggregate, independent of our ability to culture individual microbes. Early studies focused on association of changes in gut microbiota with different disease states, which was necessary to identify a potential role for microbes and generate novel hypotheses. Over the past few years the field has moved beyond associations to better understand the mechanistic implications of the microbiome in the pathophysiology of complex diseases. This movement also has resulted in a shift in our focus toward therapeutic strategies, which rely on better understanding the mediators of gut microbiota-host cross-talk. It is not surprising the gut microbiome has been implicated in the pathogenesis of functional gastrointestinal disorders given its role in modulating physiological processes such as immune development, GI motility and secretion, epithelial barrier integrity, and brain-gut communication. In this review, we focus on the current state of knowledge and future directions in microbiome research as it pertains to functional gastrointestinal disorders. We summarize the factors that help shape the gut microbiome in human beings. We discuss data from animal models and human studies to highlight existing paradigms regarding the mechanisms underlying microbiota-mediated alterations in physiological processes and their relevance in human interventions. While translation of microbiome science is still in its infancy, the outlook is optimistic and we are advancing in the right direction toward precise mechanism-based microbiota therapies.

Gastrointestinal Neuropathies: New Insights and Emerging Therapies

The bewildering complexity of the enteric nervous system makes it susceptible to develop a wide array of motility disorders, collectively called enteric neuropathies. These gastrointestinal conditions are among the most challenging to manage, mainly given poor characterization of their etiopathophysiology and outcomes. Not surprisingly, therefore, targeted or curative therapies for enteric neuropathies are lacking and management is largely symptomatic. Nonetheless, recent advances in neurogastroenterology have witnessed improvements in established strategies, such as intestinal transplantation and the emergence of new treatments including novel drugs, electrical pacing, and manipulation of fecal microbiota, as well as stem cell and gene therapy.

Regional gastrointestinal pH profile is altered in patients with type 1 diabetes and peripheral neuropathy

BACKGROUND

Gastrointestinal (GI) symptoms, such as nausea and bloating, are common in people with type 1 diabetes (T1DM). Autonomic dysfunction can lead to changes in the GI secreto-motor function which can be associated with GI symptom development. We hypothesized that regional pH profiles in T1DM differs from health and would be associated with objective physiological/clinical markers.

METHODS

Forty-seven T1DM with confirmed diabetic sensory peripheral neuropathy and 41 healthy age-matched subjects underwent standardized wireless motility capsule testing. T1DM completed the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale. Disease duration, glycemic control, insulin usage, and 24-hour heart rate variability testing were evaluated.

KEY RESULTS

In comparison to healthy subjects, gastric, and large bowel median pH were lower in T1DM (1.8 ± 1.6 vs 2.9 ± 1.5, P = 0.001 and 6.7 ± 0.6 vs 7.0 ± 0.5, P = 0.003, respectively). Additionally, change in pH across the pylorus was lower while change in pH across the ileocecal junction was higher in T1DM (5.2 ± 1.5 vs 5.8 ± 0.5, P = 0.003 and 1.8 ± 0.4 vs 1.3 ± 0.4, P < 0.0001, respectively). No difference was found in small bowel median pH. Gastric median pH was associated with small bowel transit time (r = 0.30, P = 0.049). Change in pH across the pylorus was negatively associated with fasting glycose (r = -0.35, P = 0.027). Small bowel median pH was associated with nausea (r = 0.42, P = 0.005) and small bowel transit time (r = 0.48, P = 0.0007). Large bowel median pH was associated with nausea (r = 0.35, P = 0.018) and the total GCSI score (r = 0.34, P = 0.023).

CONCLUSIONS AND INFERENCES

The GI pH profile in T1DM with DSPN is different from healthy subjects. Changes in pH profile may have important therapeutic implications and influence pharmacotherapeutic bioavailability.

Expert consensus document: Advances in the diagnosis and classification of gastric and intestinal motility disorders

Disturbances of gastric, intestinal and colonic motor and sensory functions affect a large proportion of the population worldwide, impair quality of life and cause considerable health-care costs. Assessment of gastrointestinal motility in these patients can serve to establish diagnosis and to guide therapy. Major advances in diagnostic techniques during the past 5-10 years have led to this update about indications for and selection and performance of currently available tests. As symptoms have poor concordance with gastrointestinal motor dysfunction, clinical motility testing is indicated in patients in whom there is no evidence of causative mucosal or structural diseases such as inflammatory or malignant disease. Transit tests using radiopaque markers, scintigraphy, breath tests and wireless motility capsules are noninvasive. Other tests of gastrointestinal contractility or sensation usually require intubation, typically represent second-line investigations limited to patients with severe symptoms and are performed at only specialized centres. This Consensus Statement details recommended tests as well as useful clinical alternatives for investigation of gastric, small bowel and colonic motility. The article provides recommendations on how to classify gastrointestinal motor disorders on the basis of test results and describes how test results guide treatment decisions.

Risk of small intestinal bacterial overgrowth in patients receiving proton pump inhibitors versus proton pump inhibitors plus prokinetics

Background and Aim

Intestinal dysmotility is considered a risk factor for small intestinal bacterial overgrowth (SIBO). Prokinetics improve intestinal motility and are often prescribed with proton pump inhibitors (PPIs) in patients with gastroesophageal reflux disease (GERD) and/or functional dyspepsia. The present study aimed to evaluate the prevalence of SIBO and the orocecal transit time (OCTT) in patients taking PPI compared with those taking PPI plus prokinetics.

Methods

The study is a single‐center, cross‐sectional study. Enrolled patients (with age > 12 years) were divided into two groups: patients taking PPIs for more than 3 months (Group A) and those taking PPIs with prokinetics for more than 3 months (Group B) for various indications. Lactulose breath test (LBT) for OCTT and glucose breath test (GBT) for SIBO were conducted for all patients.

Results

Of the 147 enrolled patients, SIBO was documented in 13.2% patients in Group A versus 1.8% in Group B, P = 0.018. Median OCTT in Group A was 130 (105–160) min compared with 120 (92.5–147.5) min in Group B (P = 0.010). Median OCTT among SIBO‐positive patients was 160 (140–172.5) min compared with SIBO‐negative patients, where it was 120 (103.75–150) min (P = 0.002). The duration and type of PPI used were not associated with the occurrence of SIBO in our study.

Conclusion

The use of prokinetics in patients on PPI may reduce the risk of SIBO by enhancing intestinal motility and may reduce SIBO risk associated with long‐term PPI use.

A Prospective Evaluation of Ileocecal Valve Dysfunction and Intestinal Motility Derangements in Small Intestinal Bacterial Overgrowth

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is an increasingly recognized clinical syndrome; however, its etiophathogenesis is poorly understood. We hypothesized that loss of gastric acid, a delayed intestinal transit, and ileocecal valve dysfunction may contribute to the genesis of this syndrome.

AIMS

Our primary aim was to assess these parameters using wireless motility capsule (WMC) testing and to correlate them with the presence or absence of SIBO.

METHODS

We prospectively evaluated 30 consecutive patients at a tertiary care center with suspected SIBO, diagnosed by lactulose hydrogen breath testing (LBT), and small bowel aspirate microbiology. Patients underwent WMC testing to assess ileocecal junction pressure (ICJP), small bowel transit time (SBTT), and regional gastrointestinal pH.

RESULTS

Thirty patients completed testing; 15 had a positive LBT, and 11 had a positive aspirate culture. As compared with LBT-negative patients, ICJP was lower (27.8 vs. 72.7 mmHg, p = 0.027), SBTT was longer (10.0 vs. 1.1 h, p = 0.004), gastric pH was higher (3.63 vs. 2.42, p < 0.01), and small bowel pH was higher (6.96 vs. 6.61, p = 0.05). A hypotensive ICJP (<46.61 mmHg) was more prevalent in LBT-positive patients as compared with LBT-negative patients (73.3 vs. 14.29%, p = 0.003). Logistic regression models were used to assess the magnitude of each measured WMC parameter and the presence of SIBO. p values ≤0.05 were considered statistically significant.

CONCLUSIONS

Patients with SIBO have significantly lower ICJP, prolonged SBTT, and a higher gastrointestinal pH as compared to those without SIBO. These abnormalities may play different roles in the pathogenesis of SIBO, facilitating more targeted treatment to prevent recurrences of SIBO.