Review article: Current status and future directions of ingestible electronic devices in gastroenterology.

BACKGROUND: Advances in microelectronics have greatly expanded the capabilities and clinical potential of ingestible electronic devices. AIM: To provide an overview of the structure and potential impact of ingestible devices in development that are relevant to the gastrointestinal tract. METHODS: We performed a detailed literature search to inform this narrative review. RESULTS: Technical success of ingestible electronic devices relies on the ability to miniaturise the microelectronic circuits, sensors and components for interventional functions while being sufficiently powered to fulfil the intended function. These devices offer the advantages of being convenient and minimally invasive, with real-time assessment often possible and with minimal interference to normal physiology. Safety has not been a limitation, but defining and controlling device location in the gastrointestinal tract remains challenging. The success of capsule endoscopy has buoyed enthusiasm for the concepts, but few ingestible devices have reached clinical practice to date, partly due to the novelty of the information they provide and also due to the challenges of adding this novel technology to established clinical paradigms. Nonetheless, with ongoing technological advancement and as understanding of their potential impact emerges, acceptance of such technology will grow. These devices have the capacity to provide unique insight into gastrointestinal physiology and pathophysiology. Interventional functions, such as sampling of tissue or luminal contents and delivery of therapies, may further enhance their ability to sharpen gastroenterological diagnoses, monitoring and treatment. CONCLUSIONS: The development of miniaturised ingestible microelectronic-based devices offers exciting prospects for enhancing gastroenterological research and the delivery of personalised, point-of-care medicine.

Detection of changes in regional colonic fermentation in response to supplementing a low FODMAP diet with dietary fibres by hydrogen concentrations, but not by luminal pH.

BACKGROUND: Carbohydrate fermentation plays a pivotal role in maintaining colonic health with excessive proximal and deficient distal fermentation being detrimental. AIMS: To utilise telemetric gas- and pH-sensing capsule technologies for defining patterns of regional fermentation following dietary manipulations, alongside conventional techniques of measuring fermentation. METHODS: In a double-blind crossover trial, 20 patients with irritable bowel syndrome were fed low FODMAP diets that included no extra fibre (total fibre content 24 g/day), or additional poorly fermented fibre, alone (33 g/day) or with fermentable fibre (45 g/day) for 2 weeks. Plasma and faecal biochemistry, luminal profiles defined by tandem gas- and pH-sensing capsules, and faecal microbiota were assessed. RESULTS: Plasma short-chain fatty acid (SCFA) concentrations (µmol/L) were median (IQR) 121 (100-222) with fibre combination compared with 66 (44-120) with poorly fermented fibre alone (p = 0.028) and 74 (55-125) control (p = 0.069), but no differences in faecal content were observed. Luminal hydrogen concentrations (%), but not pH, were higher in distal colon (mean 4.9 [95% CI: 2.2-7.5]) with fibre combination compared with 1.8 (0.8-2.8) with poorly fermented fibre alone (p = 0.003) and 1.9 (0.7-3.1) control (p = 0.003). Relative abundances of saccharolytic fermentative bacteria were generally higher in association with supplementation with the fibre combination. CONCLUSIONS: A modest increase in fermentable plus poorly fermented fibres had minor effects on faecal measures of fermentation, despite increases in plasma SCFA and abundance of fermentative bacteria, but the gas-sensing capsule, not pH-sensing capsule, detected the anticipated propagation of fermentation distally in the colon. The gas-sensing capsule technology provides unique insights into localisation of colonic fermentation. TRIAL REGISTRATION: ACTRN12619000691145.

Comparison of gastrointestinal landmarks using the gas-sensing capsule and wireless motility capsule.

BACKGROUND: Accurate definition of the gastroduodenal and ileocaecal junctions (GDJ, ICJ) is essential for the measurement of regional transit times. AIMS: To compare the assessment of these landmarks using the novel gas-sensing capsule and validated wireless motility capsule (WMC), and to evaluate intra-subject variance in transit times METHODS: Healthy subjects ingested the gas-sensing capsule and WMC tandemly in random order. Inter-observer agreement was evaluated by intra-class correlation coefficient (ICC). Agreement between the paired devices' transit times was assessed using Bland-Altman analysis; coefficient of variation was performed to express intra-individual variance in transit times. Similar analyses were completed with tandemly ingested gas-sensing capsules. RESULTS: The inter-observer agreement for landmarks for both capsules was excellent (mean ICC ≥0.97) in 50 studies. The GDJ was identifiable in 92% of the gas-sensing capsule studies versus 82% of the WMC studies (p = 0.27); the ICJ in 96% versus 84%, respectively (p = 0.11). In the primary cohort (n = 26), median regional transit times differed by less than 6 min between paired capsules. Bland-Altman revealed a bias of -0.12 (95% limits of agreement, -0.94 to 0.70) hours for GDJ and - 0.446 (-2.86 to 2.0) hours for ICJ. Similar results were found in a demographically distinct validation cohort (n = 24). For tandemly ingested gas-sensing capsules, coefficients of variation of transit times were 11%-35%, which were similar to variance between the paired gas-sensing capsule and WMC, as were the biases. The capsules were well tolerated. CONCLUSIONS: Key anatomical landmarks are accurately identified with the gas-sensing capsule in healthy individuals. Intra-individual differences in transit times between capsules are probably due to physiological factors. Studies in populations with gastrointestinal diseases are now required.

Hypermobile Ehlers-Danlos syndrome and disorders of the gastrointestinal tract: What the gastroenterologist needs to know.

BACKGROUND AND AIM: Hypermobile Ehlers-Danlos syndrome (hEDS) and the hypermobility spectrum disorders (HSD) can be challenging to diagnose and manage. Gastrointestinal symptoms and disorders of gut-brain interaction are common in this cohort and multifactorial in origin. The primary aim of this review is to arm the gastroenterologist with a clinically useful understanding of HSD/hEDS, by exploring the association of gastrointestinal disorders with HSD/hEDS, highlighting current pathophysiological understanding and providing a pragmatic approach to managing these patients. METHODS: Literature relevant to the gastrointestinal system and hypermobile Ehlers-Danlos syndrome was systematically searched, critically appraised, and summarized. RESULTS: Diagnosis is based upon clinical criteria and a genetic basis is yet to be defined. The prevalence of many gut symptoms, including abdominal pain (69% vs 27%, P < 0.0001), postprandial fullness (34% vs 16%, P = 0.01), constipation (73% vs 16%, P < 0.001), and diarrhea (47% vs 9%, P < 0.001) are significantly higher in HSD/hEDS compared with non-HSD/hEDS individuals. Disorders of gut-brain interaction are also common, particularly functional dyspepsia. The pathophysiology of gut symptoms is poorly understood but may involve effects of connective tissue laxity and its functional consequences, and the influence of autonomic dysfunction, medication and comorbid mental health disorders. Awareness is the key to early diagnosis. Management is limited in evidence-base but ideally should include an integrated multidisciplinary approach. CONCLUSIONS: HSD/hEDS is a multisystemic disorder in which gastrointestinal symptoms, particularly related to disorders of gut-brain interaction are common. Deficiencies in knowledge regarding the pathophysiological processes limit evidence-based interventions and remain important areas for future research.

Safety and efficacy of outpatient continuous terlipressin infusion for the treatment of portal hypertensive complications in cirrhosis.

BACKGROUND/AIM: Therapeutic options are limited for patients with hepatorenal syndrome (HRS), diuretic refractory ascites and hepatic hydrothorax who are awaiting liver transplant. We assessed the safety and efficacy of continuous terlipressin infusion (CTI) for treating these conditions in an outpatient setting. METHOD: All patients treated with CTI from May 2013 through March 2018 at our institution were initiated in-hospital on bolus dose terlipressin therapy for 24-72 h prior to commencing CTI for home therapy. Daily home visits for clinical assessment and medication administration were provided. Adverse events, effects of treatment on renal function, model for end-stage liver disease (MELD) score, and paracentesis/thoracentesis requirements were assessed. RESULTS: Twenty-three patients were included (HRS = 17; refractory ascites = 4; refractory hepatic hydrothorax = 2). Median (range) duration of outpatient CTI was 50 (1-437) days with a total of 2482 patient days of treatment. Fourteen patients (60.9%) received a liver transplant; of whom 13 (92.9%) were alive at the end of the study period. There were no cardiac or ischemic complications and no serious adverse events reported. In patients with HRS, median serum creatinine significantly decreased from 202.0 µmol/L at baseline to 125.5 µmol/L at day 14 of CTI (P = 0.0003) and remained stable thereafter. Median MELD score decreased from 22.5 to 19.0 at end of CTI (P = 0.008). Median frequency of paracentesis/thoracentesis was 4 per month prior to CTI versus 1.52 during treatment. CONCLUSION: Transplant-eligible and otherwise stable patients can be managed with CTI at home for an extended duration under supervision without adverse consequences.

Supplementing Dietary Fibers With a Low FODMAP Diet in Irritable Bowel Syndrome: A Randomized Controlled Crossover Trial.

BACKGROUND & AIMS: Institution of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) in patients with irritable bowel syndrome (IBS) may lead to inadequate fiber intake. This trial aimed to investigate the effects of supplementing specific fibers concomitantly with a low FODMAP diet on relevant clinical and physiological indices in symptomatic patients with IBS. METHODS: A double-blind crossover trial was conducted in which 26 patients with IBS were randomly assigned to 1 of 3 low FODMAP diets differing only in total fiber content: control, 23 g/d; sugarcane bagasse, 33 g/d; or fiber combination (sugarcane bagasse with resistant starch), 45 g/d. Each diet lasted 14 days with most food provided and ≥21 days' washout between. Endpoints were assessed during baseline and dietary interventions. RESULTS: From a median IBS Severity Scoring System total score at baseline of 305, all diets reduced median scores by >50 with no differences in rates of symptom response between the diets: control (57%), sugarcane bagasse (67%), fiber combination (48%) (P = .459). Stool output was ∼50% higher during the fiber-supplemented vs control diets (P < .001 for both). While there were no overall differences overall in stool characteristics, descriptors, and water content, or in gastrointestinal transit times, supplementation with sugarcane bagasse normalized both low stool water content and slow colonic transit from during the control diet. CONCLUSIONS: Concomitant supplementation of fibers during initiation of a low FODMAP diet did not alter symptomatic response in patients with IBS but augmented stool bulk and normalized low stool water content and slow transit. Resistant starch did not exert additional symptomatic benefits over sugarcane bagasse alone. (Australia and New Zealand Clinical Trial Registry; Number, ACTRN12619000691145).

Sepsis and siderosis, Yersinia enterocolitica and hereditary haemochromatosis.

A 60-year-old woman was admitted with sepsis, relative bradycardia, CT evidence of numerous small liver abscesses and 'skin bronzing' consistent with hereditary haemochromatosis (HH). Yersinia enterocolitica O:9 infection was confirmed by serology specimens taken 10 days apart. Iron overload was detected, and homozygous C282Y gene mutation confirmed HH. Liver biopsy revealed grade IV siderosis with micronodular cirrhosis. Haemochromatosis is a common, inherited disorder leading to iron overload that can produce end-organ damage from excess iron deposition. Haemochromatosis diagnosis allowed aggressive medical management with phlebotomy achieving normalisation of iron stores. Screening for complications of cirrhosis was started that included hepatoma surveillance. Iron overload states are known to increase patient susceptibility to infections caused by lower virulence bacteria lacking sophisticated iron metabolism pathways, for example, Yersinia enterocolitica Although these serious disseminated infections are rare, they may serve as markers for occult iron overload and should prompt haemochromatosis screening.