Delayed small intestinal transit in patients with long-standing type 1 diabetes mellitus: investigation of the relationships with clinical features, gastric emptying, psychological distress, and nutritional parameters

MRI-Based Quantification of Pan-Alimentary Function and Motility in Subjects with Diabetes and Gastrointestinal Symptoms

Background: Diabetes-induced gastrointestinal (GI) symptoms are common but difficult to correctly diagnose and manage. We used multi-segmental magnetic resonance imaging (MRI) to evaluate structural and functional GI parameters in diabetic patients and to study the association with their symptomatic presentation. Methods: Eighty-six participants (46 with diabetes and GI symptoms, 40 healthy controls) underwent baseline and post-meal MRI scans at multiple timepoints. Questionnaires were collected at inclusion and following the scans. Data were collected from the stomach, small bowel, and colon. Associations between symptoms and collected data were explored. Utilizing machine learning, we determined which features differentiated the two groups the most. Key Results: The patient group reported more symptoms at inclusion and during MRI scans. They showed 34% higher stomach volume at baseline, 40% larger small bowel volume, 30% smaller colon volume, and less small bowel motility postprandially. They also showed positive associations between gastric volume and satiety scores, gastric emptying time and reflux scores, and small bowel motility and constipation scores. No differences in gastric emptying were observed. Small bowel volume and motility were used as inputs to a classification tool that separated patients and controls with 76% accuracy. Conclusions: In this work, we studied structural and functional differences between patients with diabetes and GI symptoms and healthy controls and observed differences in stomach, small bowel, and colon volumes, as well as an adynamic small bowel in patients with diabetes and GI symptoms. Associations between recorded parameters and perceived symptoms were also explored and discussed.

GI factors, potential to predict prostate motion during radiotherapy; a scoping review

Purpose

A scoping literature review was conducted to identify gastrointestinal (GI) factors most likely to influence prostate motion during radiotherapy. We proffer that patient specific measurement of these GI factors could predict motion uncertainty during radiotherapy, facilitating personalised care by optimising treatment technique e.g., daily adaption or via bespoke patient pre-habilitation and preparation.

Methods

The scoping review was undertaken as per JBI guidelines. Searches were conducted across four databases: Ovid Medline®, EMBASE, CINAHL and EBSCO discovery. Articles written in English from 2010-present were included. Those pertaining to paediatrics, biological women exclusively, infectious and post-treatment GI morbidity and diet were excluded.Common GI factors impacting men were identified and related symptoms, incidence and measurement tools examined. Prevalence among persons with prostate cancer was explored and suitable assessment tools discussed.

Results

A preliminary search identified four prominent GI-factors: mental health, co-morbidity and medication, physical activity, and pelvic floor disorder. The scoping search found 3644 articles; 1646 were removed as duplicates. A further 1249 were excluded after title and abstract screening, 162 remained subsequent to full text review: 42 mental health, 53 co-morbidity and medication, 39 physical activity and 28 pelvic floor disorder.Six GI factors prevalent in the prostate cancer population and estimated most likely to influence prostate motion were identified: depression, anxiety, diabetes, obesity, low physical activity, and pelvic floor disorder. Reliable, quick, and easy to use tools are available to quantify these factors.

Conclusion

A comprehensive GI factor assessment package suitable to implement into the radiotherapy clinic has been created. Unveiling these GI factors upfront will guide improved personalisation of radiotherapy.

Association between Gut Dysbiosis and the Occurrence of SIBO, LIBO, SIFO and IMO

Gut microbiota is the aggregate of all microorganisms in the human digestive system. There are 1014 CFU/mL of such microorganisms in the human body, including bacteria, viruses, fungi, archaea and protozoa. The Firmicutes and Bacteroidetes bacteria phyla comprise 90% of the human gut microbiota. The microbiota support the healthy functioning of the human body by helping with digestion (mainly via short-chain fatty acids and amino acids) and producing short-chain fatty acids. In addition, it exhibits many physiological functions, such as forming the intestinal epithelium, intestinal integrity maintenance, the production of vitamins, and protection against pathogens. An altered composition or the number of microorganisms, known as dysbiosis, disrupts the body's homeostasis and can lead to the development of inflammatory bowel disease, irritable bowel syndrome, and metabolic diseases such as diabetes, obesity and allergies. Several types of disruptions to the gut microbiota have been identified: SIBO (Small Intestinal Bacterial Overgrowth), LIBO (Large Intestinal Bacterial Overgrowth), SIFO (Small Intestinal Fungal Overgrowth), and IMO (Intestinal Methanogen Overgrowth). General gastrointestinal problems such as abdominal pain, bloating, gas, diarrhoea and constipation are the main symptoms of dysbiosis. They lead to malabsorption, nutrient deficiencies, anaemia and hypoproteinaemia. Increased lipopolysaccharide (LPS) permeability, stimulating the inflammatory response and resulting in chronic inflammation, has been identified as the leading cause of microbial overgrowth in the gut. The subject literature is extensive but of limited quality. Despite the recent interest in the gut microbiome and its disorders, more clinical research is needed to determine the pathophysiology, effective treatments, and prevention of small and large intestinal microbiota overgrowth. This review was designed to provide an overview of the available literature on intestinal microbial dysbiosis (SIBO, LIBO, SIFO and IMO) and to determine whether it represents a real threat to human health.

Show Me What You Have Inside-The Complex Interplay between SIBO and Multiple Medical Conditions-A Systematic Review

The microbiota, as a complex of microorganisms in a particular ecosystem, is part of the wider term-microbiome, which is defined as the set of all genetic content in the microbial community. Imbalanced gut microbiota has a great impact on the homeostasis of the organism. Dysbiosis, as a disturbance in bacterial balance, might trigger or exacerbate the course of different pathologies. Small intestinal bacterial overgrowth (SIBO) is a disorder characterized by differences in quantity, quality, and location of the small intestine microbiota. SIBO underlies symptoms associated with functional gastrointestinal disorders (FGD) as well as may alter the presentation of chronic diseases such as heart failure, diabetes, etc. In recent years there has been growing interest in the influence of SIBO and its impact on the whole human body as well as individual systems. Therefore, we aimed to investigate the co-existence of SIBO with different medical conditions. The PubMed database was searched up to July 2022 and we found 580 original studies; inclusion and exclusion criteria let us identify 112 eligible articles, which are quoted in this paper. The present SIBO diagnostic methods could be divided into two groups-invasive, the gold standard-small intestine aspirate culture, and non-invasive, breath tests (BT). Over the years scientists have explored SIBO and its associations with other diseases. Its role has been confirmed not only in gastroenterology but also in cardiology, endocrinology, neurology, rheumatology, and nephrology. Antibiotic therapy could reduce SIBO occurrence resulting not only in the relief of FGD symptoms but also manifestations of comorbid diseases. Although more research is needed, the link between SIBO and other diseases is an important pathway for scientists to follow.

Gastrointestinal function in diabetes is affected regardless of asymptomatic appearance

BACKGROUND

Gastrointestinal dysmotility may exist without concomitant symptoms. We hypothesize that asymptomatic individuals with diabetes have altered gastrointestinal function associated with age, cardiac vagal tone and glycaemic control.

METHODS

One hundred fifty-four asymptomatic participants (61 with type 1 diabetes (T1D), 70 type 2 diabetes (T2D) and 23 healthy volunteers (HV)) underwent wireless motility capsule investigation. Transit times, motility indices and pH were retrieved. Age, cardiac vagal tone, glucose and haemoglobin A1c levels were collected.

RESULTS

In T1D, prolongation of colonic (p = 0.03) and whole-gut transit times (p = 0.04) were shown. Transpyloric pH rise was decreased in T1D (p = 0.001) and T2D (p = 0.007) and was associated with cardiac vagal tone (p = 0.03) or glucose (p = 0.04) and haemoglobin A1c (p = 0.005). Ileocaecal pH fall was decreased in T2D (p < 0.001).

CONCLUSIONS

Gastrointestinal function was altered in asymptomatic individuals with diabetes. These findings call for further investigations of gastrointestinal function in order to identify risk factors or even predictors for diabetic enteropathy, particularly when glycaemic control is impaired.

The prevalence of small intestinal bacterial overgrowth in diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

We conducted this systematic review and meta-analysis to estimate the prevalence of SIBO in diabetic patients and to determine the association between SIBO and diabetes.

METHODS

A comprehensive literature search of the PubMed, Cochrane Library and EMBASE databases from inception to June 2021 was conducted for studies correlating SIBO with diabetes. Studies were screened, and relevant data were extracted and analysed. The pooled prevalence of SIBO among diabetic patients and the odds ratio of SIBO among diabetic patients compared with controls were calculated.

RESULTS

Fourteen studies including 1417 diabetic patients and 649 controls met the inclusion criteria. The pooled prevalence of SIBO in diabetes was 29% (95% CI 20-39%). The odds ratio of SIBO in diabetic patients was 2.91 (95% CI 0.82-10.32, p=0.1) compared with controls. Subgroup analyses showed that the prevalence of SIBO in diabetes was higher in studies using jejunal aspirate culture for diagnosis (39%, 95% CI 12-66%) than in those using the lactulose breath test (31%, 95% CI 18-43%) or glucose breath test (29%, 95% CI 14-43%). The prevalence of SIBO in diabetes was higher in studies conducted in Western countries (35%, 95% CI 21-49%) than in those conducted in Eastern countries (24%, 95% CI 14-34%), and the prevalence of SIBO in type 1 diabetes (25%, 95% CI 14%-36%) was not significantly different from that in type 2 diabetes (30%, 95% CI 13%-47%).

CONCLUSIONS

Twenty-nine percent of diabetic patients tested positive for SIBO, and the risk of SIBO in diabetic patients was 2.91 times higher than that in patients without diabetes. Diabetes could be a predisposing factor for the development of SIBO, especially among patients diagnosed by jejunal aspirate culture or those in Western populations.

Enhanced Store-Operated Ca2+ Signal of Small Intestinal Smooth Muscle Cells Accelerates Small Bowel Transit Speed in Type 1 Diabetic Mouse

Aims: The underlying mechanism of diabetic enteropathy, a common complication of type 1 diabetes, remains unclear. Store-operated Ca²⁺ entry (SOCE) is a ubiquitous type of Ca²⁺ influx involved in various cellular functions. Here, we show that SOCE-related stromal interaction molecule 1 (STIM1) and Orai1 participate in inappropriate cellular Ca²⁺ homeostasis, augmenting agonist-induced small intestinal smooth muscle contraction and small bowel transit speed in a mouse model of type 1 diabetes.

Methods and Results: We used small interfering (si)RNA to suppress STIM1 and Orai1 proteins, and employed intracellular Ca²⁺, small intestinal contraction and intestinal transit speed measurement to investigate the functional change. We found that SOCE activity and Orai1 and STIM1 expression levels of small intestinal smooth muscle were significantly increased in cells cultured in high glucose medium or in diabetic mice. Gastrointestinal transit speed and SOCE-mediated contractions were markedly increased in diabetic mice; Knocking down Orai1 or STIM1 with siRNA rescued both alterations in diabetic mice. However, the Orai1-large conductance Ca²⁺-activated K⁺ (BK_Ca) channel interaction was decreased in diabetic mice, and suppressing Orai1 expression or inhibiting the BK_Ca channel increased agonist-induced small intestinal contractions in normal mice.

Conclusion: We concluded that the increased SOCE caused by excessive STIM1 and Orai1 expression and decreased Orai1-BK_Ca interaction augmented small intestinal smooth muscle contraction and accelerated small bowel transit speed in diabetic mice. This finding demonstrates a pathological role for SOCE in diabetic enteropathy and provides a potential therapeutic target for diabetic enteropathy.

Assessment of Gastrointestinal Autonomic Dysfunction: Present and Future Perspectives

The autonomic nervous system delicately regulates the function of several target organs, including the gastrointestinal tract. Thus, nerve lesions or other nerve pathologies may cause autonomic dysfunction (AD). Some of the most common causes of AD are diabetes mellitus and α-synucleinopathies such as Parkinson’s disease. Widespread dysmotility throughout the gastrointestinal tract is a common finding in AD, but no commercially available method exists for direct verification of enteric dysfunction. Thus, assessing segmental enteric physiological function is recommended to aid diagnostics and guide treatment. Several established assessment methods exist, but disadvantages such as lack of standardization, exposure to radiation, advanced data interpretation, or high cost, limit their utility. Emerging methods, including high-resolution colonic manometry, 3D-transit, advanced imaging methods, analysis of gut biopsies, and microbiota, may all assist in the evaluation of gastroenteropathy related to AD. This review provides an overview of established and emerging assessment methods of physiological function within the gut and assessment methods of autonomic neuropathy outside the gut, especially in regards to clinical performance, strengths, and limitations for each method.

Gastrointestinal pH, Motility Patterns, and Transit Times After Roux-en-Y Gastric Bypass

BACKGROUND

Studies investigating the underlying pathophysiology are needed to help explain and understand the postoperative complications following Roux-en-Y gastric bypass (RYGB) surgery. This study aimed to characterize segmental gastrointestinal pH profiles, motility measures, and transit times in patients with RYGB.

MATERIALS AND METHODS

Nineteen patients with RYGB underwent a standardized wireless motility capsule assessment. The oro-cecal segment was defined from capsule ingestion until the passage of the ileocecal junction. Segmental median pH, motility index, and transit time were determined for the oro-cecal and colonic segment as well as for the first and last hour of both these segments. For comparison to reference values, data from 17 healthy age- and gender-matched controls was used. A mixed effect model was used to describe differences between groups.

RESULTS

Median pH was high in patients with RYGB during the first hour of the oro-cecal segment (6.45 ± 0.4 vs 3.65 ± 1.55 pH units for healthy controls; P < 0.001), as well as during the entire oro-cecal segment (6.97 ± 0.4 vs 5.51 ± 1.1 pH units; P < 0.001). The same was evident for the median motility index (152 ± 64 vs 35.8 ± 31.1 mmHg*sec/min; P < 0.001 and 130 ± 65.9 vs 89.1 ± 20 mmHg*sec/min; P < 0.012, respectively). Median motility index was low the first hour of the colon (55.2 ± 45.7 vs 122 ± 77.9 mmHg*sec/min; P < 0.002). Additionally, patients had short oro-cecal transit time (5.8 ± 1.6 vs 7.6 ± 1.4 h; P < 0.001) and long colonic transit time (29.4 ± 17.5 vs 19.6 ± 12.2 h; P = 0.048).

CONCLUSIONS

In patients with RYGB, the oro-cecal segment was characterized by an alkaline intraluminal environment, high motility activity, and short transit time. In contrast, colonic transit time was long.

Gastrointestinal symptoms and cardiac vagal tone in type 1 diabetes correlates with gut transit times and motility index

BACKGROUND

Although gastrointestinal (GI) symptoms are common in diabetes, they frequently do not correlate with measurable sensorimotor abnormalities. The wireless motility capsule (WMC) measures pressure, temperature, and pH as it traverses the GI tract wherefrom transit times and motility indices are derived. The aim was to investigate whether GI symptoms correlate with changes in (a) segmental transit times, (b) segmental motility index, (c) cardiac vagal tone, or (d) presence/absence of peripheral neuropathy in type 1 diabetes.

METHODS

Gastrointestinal symptoms in 104 participants with type 1 diabetes were measured using Gastroparesis Cardinal Symptoms Index and Gastrointestinal Symptom Rating Scale. All underwent standardized WMC investigation measuring segmental transit time and motility. Cardiac vagal tone and presence of peripheral neuropathy were measured using electrocardiographic and nerve conduction velocity testing.

KEY RESULTS

Colonic transit time was correlated with postprandial fullness (P = .01) and constipation (P = .03), while decreased colonic motility index was correlated with diarrhea (P = .01) and decreased bloating (P < .05). Symptoms were not correlated with gastric or small bowel transit time or motility index. In participants with low cardiac vagal tone, gastric motility index (P < .01) and colonic transit time (P < .05) were increased, but not in those with peripheral neuropathy. Abdominal pain was decreased with both peripheral neuropathy (P = .04) and decreased cardiac vagal tone (P = .02).

CONCLUSIONS AND INFERENCES

This study supports the rationale for whole gut investigation, using not only transit times but incorporating contractility indices as well. Furthermore, a decreased parasympathetic modulation and an increased hyposensate state appear to be present in type 1 diabetes.

Association between small intestinal bacterial overgrowth and beta-cell function of type 2 diabetes

Aims

Previous studies suggest that small intestinal bacterial overgrowth (SIBO) is associated with type 2 diabetes. However, few studies have evaluated the association between SIBO and beta-cell function in type 2 diabetes. The aim of this study was to evaluate whether beta-cell function was associated with SIBO.

Materials and methods

One hundred four patients with type 2 diabetes were included in this study. Based on the presence of SIBO, the patients were divided into SIBO-positive and SIBO-negative groups. Oral glucose tolerance tests were performed. Insulin sensitivity was measured using 1/homeostasis model assessment of insulin resistance (1/HOMA-IR) and the insulin sensitivity index (ISIM). Insulin release was calculated by HOMA-β, early-phase insulin secretion index InsAUC₃₀/GluAUC₃₀, and total-phase insulin secretion index InsAUC₁₂₀/GluAUC₁₂₀.

Results

Compared with the SIBO-negative group, patients in the SIBO-positive group showed a higher glucose level at 120 minutes, HbA1c, 1/HOMA-IR, and ISIM and a lower HOMA-β level, early-phase InsAUC₃₀/GluAUC₃₀, and total-phase InsAUC₁₂₀/GluAUC₁₂₀. Multiple linear regression analysis showed that body mass index, glucose at 0 minutes, and SIBO were independently associated with the early-phase and total-phase insulin secretion.

Conclusion

SIBO may be involved in lower levels of insulin release and worse glycemic control.

The High-Resolution Three-Dimensional Magnetic Detector System 3D-Magma Accurately Measures Gastric and Small Bowel Motility in People with Type 2 Diabetes with Neuropathy

Gastroparesis is an important complication of diabetes. Motility disorders are underdiagnosed and can lead to unexplained hypoglycemia. Currently diagnostic options are limited. All established methods harbor certain disadvantages. The 3D-MAGMA system is capable of reliably measuring gastric and small intestinal motility. The aim of the current study was to determine if 3D-MAGMA is able to detect changes in intestinal motility in people with type 2 diabetes. 18 healthy volunteers and 19 people with type 2 diabetes underwent motility testing by 3D-MAGMA. In the control group the retention time in the stomach was 33.0 [min] compared to 75.3 [min] in the diabetes group. The median time in the duodenum was 12.7 [min] compared to 8.1 [min]. The time for the first 50 cm of the jejunum was 29.9 [min] compared to 28.2 [min]. Discussion and conclusion: 3D-MAGMA is able to detect changes in intestinal motility. Its clinical value might be useful in patients with fluctuating blood glucose levels and unexplained hypoglycemic episodes.

Type 1 diabetes mellitus: Complex interplay of oxidative stress, cytokines, gastrointestinal motility and small intestinal bacterial overgrowth

BACKGROUND

Oxidative stress is risk factor in progression of diabetes. It can increase cytokine production via several different mechanisms. Inflammation can affect gut neural apparatus that may lead to dysmotility which may exaggerate occurrence of bacterial overgrowth in intestine. Thus, a study was planned to understand the complex interplay of oxidative stress, inflammatory cytokines, gut motility and small intestinal bacterial overgrowth in type 1 diabetes mellitus (T1DM) patients.

MATERIALS AND METHODS

Seventy-five T1DM patients and 75 healthy controls were enrolled. Small intestinal bacterial overgrowth (SIBO) and orocecal transit time (OCTT) were measured using noninvasive glucose and lactulose hydrogen breath tests, respectively. Plasma levels of interleukin-6 (IL-6), tissue necrosis factor-alfa (TNF-α) and interleukin-10 (IL-10) were measured in all subjects by ELISA. Oxidative stress and anti-oxidant parameters were measured by standard methods.

RESULTS

Out of 75 T1DM patients, 36 were males with Mean ± SD age 22.3 ± 5.2 years, IL-6, TNF-α and IL-10 were significantly higher (P < 0.05) in T1DM patients as compared to controls. Lipid peroxidation (LPO) was significantly increased (P < 0.001), while reduced glutathione (GSH) significantly decreased (P < 0.01), whereas superoxide dismutase (SOD) and catalase significantly higher (P < 0.05) in T1DM patients as compared to controls. Positive correlation was observed between glycated haemoglobin (HbA1c) levels with LPO and negative correlation with GSH. Further, there was positive correlation between LPO and inflammatory cytokines (IL-6 & IL-10). OCTT was delayed and SIBO significantly higher in patients as compared to controls. On comparison of T1DM based on duration of disease, effect of all parameters was more pronounced in disease duration ≥5 years.

CONCLUSION

This study indicates that there is association between hyperglycaemia, oxidative stress (LPO), anti-oxidants (GSH, SOD and catalase), inflammatory cytokines, gut motility (OCTT), and small intestinal overgrowth in type 1 diabetes mellitus patients. This association is intensified as duration of disease increases.

Diabetes and the Small Intestine

OPINION STATEMENT

Diabetes mellitus (DM) and its associated complications are becoming increasingly prevalent. Gastrointestinal symptoms associated with diabetes is known as diabetic enteropathy (DE) and may manifest as either diarrhea, fecal incontinence, constipation, dyspepsia, nausea, and vomiting or a combination of symptoms. The long-held belief that vagal autonomic neuropathy is the primary cause of DE has recently been challenged by newer theories of disease development. Specifically, hyperglycemia and the resulting oxidative stress on neural networks, including the nitrergic neurons and interstitial cells of Cajal (ICC), are now believed to play a central role in the development of DE. DE occurs in the majority of patients with diabetes; however, tools for early diagnosis and targeted therapy to counter the detrimental and potentially irreversible effects on the small bowel are lacking. Delay in diagnosis is further compounded by the fact that DE symptoms overlap with those of gastroparesis or can be confused with side effects from diabetes medications. Still, early recognition of the presence of DE is essential to mitigating symptoms and preventing further progression of complications including dysmotility and malabsorption. Current diagnostic modalities include manometry, wireless motility capsule (SmartPill™), and scintigraphy; however, these are not regularly utilized in clinical practice due to limited availability. Several medications are available for symptom relief in DE patients including rifaximin for small intestinal bacterial overgrowth (SIBO) and somatostatin analogues for diarrhea. While rodent models on stem cell therapy and alteration of the microbiome are promising, there is still a great need for further research on the pathologic underpinnings and development of novel treatment modalities for DE.

Levothyroxine therapy and impaired clearance are the strongest contributors to small intestinal bacterial overgrowth: Results of a retrospective cohort study

AIM

To identify a set of contributors, and weight and rank them on a pathophysiological basis.

METHODS

Patients who have undergone a lactulose or glucose hydrogen breath test to rule out small intestinal bacterial overgrowth (SIBO) for various clinical symptoms, including diarrhoea, weight loss, abdominal pain, cramping or bloating, were seen as eligible for inclusion in a retrospective single-centre study. Clinical data such as co-morbidities, medication, laboratory parameters and other possible risk factors have been identified from the electronic data system. Cases lacking or with substantially incomplete clinical data were excluded from the analysis. Suspected contributors were summarised under four different pathophysiological pathways (impaired gastric acid barrier, impaired intestinal clearance, immunosuppression and miscellaneous factors including thyroid gland variables) and investigated using the χ² test, Student’s t-test and logistic regression models.

RESULTS

A total of 1809 patients who had undergone hydrogen breath testing were analysed. Impairment of the gastric acid barrier (gastrectomy, odds ratio: OR = 3.5, PPI therapy OR = 1.4), impairment of intestinal clearance (any resecting gastric surgery OR = 2.6, any colonic resection OR = 1.9, stenosis OR = 3.4, gastroparesis OR = 3.4, neuropathy 2.2), immunological factors (any drug-induced immunosuppression OR = 1.8), altered thyroid gland metabolism (hypothyroidism OR = 2.6, levothyroxine therapy OR = 3.0) and diabetes mellitus (OR = 1.9) were associated significantly to SIBO. Any abdominal surgery, ileocecal resection, vagotomy or IgA-deficiency did not have any influence, and a history of appendectomy decreased the risk of SIBO. Multivariate analysis revealed gastric surgery, stenoses, medical immunosuppression and levothyroxine to be the strongest predictors. Levothyroxine therapy was the strongest contributor in a simplified model (OR = 3.0).

CONCLUSION

The most important contributors for the development of SIBO in ascending order are immunosuppression, impairment of intestinal clearance and levothyroxine use, but they do not sufficiently explain its emergence.

Evaluation of gastric blood supply in diabetic patients with gastroparesis by contrast-enhanced ultrasound

OBJECTIVE

Improvement in regional blood flow has been shown to ameliorate diabetic gastroparesis. We compared the gastric blood supply in patients with diabetes with gastroparesis with that in healthy subjects, by using contrast-enhanced ultrasound (CEUS).

METHODS

30 healthy subjects and 40 patients with diabetic gastroparesis were enrolled. The CEUS parameters of greater curvatures of the antrum (GCOA) and lesser curvatures of the antrum (LCOA), including peak intensity (PI) and the area under the curve (AUC), were compared between the two groups.

RESULTS

Intraclass correlation coefficient (ICC) for PI in healthy subjects measured on CEUS were 0.831-0.857 and 0.803-0.823, respectively. Intra-ICC and inter-ICC values for AUC were 0.805-0.823 and 0.813-0.815, respectively. In both groups, no significant difference was observed in PI and AUC values of GCOA and LCOA (p > 0.05). The PI and AUC of GCOA and LCOA in the diabetes group were less than those in the normal group (p < 0.05).

CONCLUSION

CEUS can assess stomach wall vascularity with a high reproducibility. Microcirculation in the antrum of patients with diabetic gastroparesis is poorer than that of normal group, which is consistent with the mechanisms of diabetic neuropathy. CEUS can be used for evaluation of microvascular perfusion in patients with stomach wall disease. Advances in knowledge: This was the first study to use CEUS for assessment of blood supply of the gastric wall and to compare microvascular perfusion between healthy individuals and patients with diabetes with gastroparesis.

Evaluation of gastric emptying in diabetic gastropathy by an ultrasonic whole stomach cylinder method

In order to explore the accuracy of ultrasonic whole stomach cylinder measurement (UWSCM) in the evaluation of gastric emptying, we measured the gastric emptying times (ET) at 25% (T1), 50% (T2) and 75% (T3) of healthy subjects and patients with diabetic gastropathy by UWSCM and scintigraphy. The ET of patients were compared with their clinical symptom scores. We found that the ET measured by UWSCM showed no significant difference with scintigraphy (p > 0.05). The correlation between them was good, and the correlation coefficient of T3 reached 0.744 (p < 0.05). All emptying times in the diabetic patients were longer than those in the healthy subjects (p < 0.05). The T3 in the diabetic group measured by UWSCM had the best correlation with the symptom index (r = 0.469, p < 0.05). We conclude that ET measured by UWSCM is accurate and T3 combining the symptoms index provides an accurate clinical basis for gastropathy.

Hydrogen breath tests in gastrointestinal diseases

Hydrogen breath tests are widely used to explore pathophysiology of functional gastrointestinal (GI) disorders. Small intestinal bacterial overgrowth (SIBO) and carbohydrate malabsorption are disorders detected by these tests that have been proposed to be of great importance for symptoms of GI diseases. Glucose hydrogen breath test is more acceptable for diagnosis of SIBO whereas lactose and fructose hydrogen breath tests are used for detection of lactose and fructose maldigestion respectively. Lactulose hydrogen breath test is also used widely to measure the orocecal transit time for GI motility. These methods are noninvasive and inexpensive. Many patients with functional gut disorders are unaware of the relationship between diet and GI symptoms they present. In particular, patients with chronic symptoms may regard their condition as normal and may not be aware that their symptoms can be effectively managed following a proper diagnosis. Patients with symptoms of abdominal pain, bloating, flatulence and altered bowel movements (diarrhea and constipation), or with a medical diagnosis of irritable bowel syndrome or celiac disease, may have undiagnosed carbohydrate malabsorption or SIBO. Hydrogen breath tests are specific and sensitive diagnostic tests that can be used to either confirm or eliminate the possibility of carbohydrate malabsorption or SIBO in such patients. Breath tests, though valuable tools, are underutilized in evaluating dyspepsia and functional bloating and diarrhea as well as suspected malabsorption. However, because of their simplicity, reproducibility and safety of procedure they are now being substituted to more uncomfortable and expensive techniques that were traditionally used in gastroenterology.

Small intestinal bacterial overgrowth: what it is and what it is not

PURPOSE OF REVIEW

To critically review recent literature on small intestinal bacterial overgrowth (SIBO).

RECENT FINDINGS

When originally described, SIBO was added to the list of causes of the malabsorption syndrome and the pathophysiology of its consequences for the digestion and absorption of various nutrients was gradually revealed. More recently, SIBO was incriminated as a cause of diarrhea, especially in the elderly. However, the suggestion that SIBO may be a causative factor in irritable bowel syndrome and of its constituent symptoms has sparked debate and controversy on the very definition of SIBO. This debate revolves around the tests employed and the diagnostic cut-off values (for bacterial numbers) used to diagnose SIBO in clinical practice.

SUMMARY

A fundamental problem with SIBO, and one that allows controversy to simmer, is the lack of a universally accepted and applied gold standard for the diagnosis of SIBO. Hopefully, the application of molecular microbiological methods to the characterization of the small intestinal microbiome will tell us, once and for all, what is normal and when 'abnormality' is truly responsible for symptoms and disease. Meanwhile, therapy remains, for the most part, empirical and is based on the correction, wherever possible, of any underlying cause, attention to nutritional deficiencies, and the use of antibiotics.