American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation.

INTRODUCTION: Chronic idiopathic constipation (CIC) is a common disorder associated with significant impairment in quality of life. This clinical practice guideline, jointly developed by the American Gastroenterological Association and the American College of Gastroenterology, aims to inform clinicians and patients by providing evidence-based practice recommendations for the pharmacological treatment of CIC in adults. METHODS: The American Gastroenterological Association and the American College of Gastroenterology formed a multidisciplinary guideline panel that conducted systematic reviews of the following agents: fiber, osmotic laxatives (polyethylene glycol, magnesium oxide, lactulose), stimulant laxatives (bisacodyl, sodium picosulfate, senna), secretagogues (lubiprostone, linaclotide, plecanatide), and serotonin type 4 agonist (prucalopride). The panel prioritized clinical questions and outcomes and used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence for each intervention. The Evidence to Decision framework was used to develop clinical recommendations based on the balance between the desirable and undesirable effects, patient values, costs, and health equity considerations. RESULTS: The panel agreed on 10 recommendations for the pharmacological management of CIC in adults. Based on available evidence, the panel made strong recommendations for the use of polyethylene glycol, sodium picosulfate, linaclotide, plecanatide, and prucalopride for CIC in adults. Conditional recommendations were made for the use of fiber, lactulose, senna, magnesium oxide, and lubiprostone. DISCUSSION: This document provides a comprehensive outline of the various over-the-counter and prescription pharmacological agents available for the treatment of CIC. The guidelines are meant to provide a framework for approaching the management of CIC; clinical providers should engage in shared decision making based on patient preferences as well as medication cost and availability. Limitations and gaps in the evidence are highlighted to help guide future research opportunities and enhance the care of patients with chronic constipation.

Efficacy of lubiprostone for functional constipation treatment in adolescents and children: Randomized controlled trial.

OBJECTIVES: Adolescent and pediatric functional constipation (FC) is a common clinical problem. Currently, data on lubiprostone for the treatment of pediatric FC are scarce. This study investigated the efficacy and safety of lubiprostone in the treatment of pediatric FC. METHODS: In a single-blinded, randomized controlled study, we included 280 patients aged 8-18 years with FC. Patients were randomized either to a weight-based lubiprostone dose (n = 140) or conventional laxatives (n = 140), including lactulose, bisacodyl, or sodium picosulfate, for 12 weeks, followed by 4 weeks posttreatment follow-up. RESULTS: Improvement in constipation was achieved in 128 (91.4%) patients in the lubiprostone group, and in 48 (34.3%) patients of the conventional therapy group (p < 0.001) and was sustained after treatment discontinuation. One quarter of the lubiprostone group experienced the first spontaneous bowel motion within 48 h after dose initiation. A total of 75.7% of the lubiprostone group could achieve and sustain Bristol stool form of 3 or 4 during the last 4 weeks of therapy and through the 4 weeks of follow-up versus 50 (35.7%) patients in the conventional therapy group (p < 0.001). No life-threatening adverse drug reactions were encountered, and no treatment-related discontinuation. Mild self-limited colicky abdominal pain and headache were the most prevalent side effects in the lubiprostone group. CONCLUSIONS: Lubiprostone is an effective and well-tolerated pharmacotherapy for youthful age and pediatric age groups, which may alter the paradigm of pediatric FC treatment.

Plasma measurements of the dual sugar test reveal carbohydrate immediately alleviates intestinal permeability caused by exertional heat stress.

The aim of this set of randomised cross-over studies was to determine the impact of progressive heat exposure and carbohydrate or protein feeding during exertional stress on small intestine permeability using a dual sugar test. In our previous work, and typically in the field, recovery of lactulose and l-rhamnose is measured cumulatively in urine. This follow-up study exploits our novel high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) protocol to accurately quantify the sugars in plasma. Endurance-trained participants completed experimental trial A (ET-A; n = 8), consisting of 2 h running at 60% V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in temperate, warm and hot ambient conditions, and/or experimental trial B (ET-B; n = 9), consisting of 2 h running at 60% V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in the heat while consuming water, carbohydrate or protein. Blood samples were collected and plasma lactulose (L) and l-rhamnose (R) appearance, after dual sugar solution ingestion at 90 min of exercise, was quantified by HPAEC-PAD to measure plasma L/R and reveal new information about intestinal permeability immediately post-exercise and during recovery. In ET-A, plasma L/R increased immediately post-exercise in hot compared with temperate and warm conditions, while, in ET-B, carbohydrate alleviated this, and this information was otherwise missed when measuring urine L/R. Consuming carbohydrate or protein before and during exercise attenuated small intestine permeability throughout recovery from exertional heat stress. We recommend using the dual sugar test with quantification of plasma sugars by HPAEC-PAD at intervals to maximise intestinal permeability data collection in exercise gastroenterology research, as this gives additional information compared to urinary measurements. KEY POINTS: Intestinal permeability is typically assessed using a dual sugar test, by administering a drink containing non-metabolisable sugars (e.g. lactulose (L) and l-rhamnose (R)) that can enter the circulation by paracellular translocation when the epithelium is compromised, and are subsequently measured in urine. We demonstrate that our recently developed ion chromatography protocol can be used to accurately quantify the L/R ratio in plasma, and that measuring L/R in plasma collected at intervals during the post-exercise recovery period reveals novel acute response information compared to measuring 5-h cumulative urine L/R. We confirm that exercising in hot ambient conditions increases intestinal epithelial permeability immediately after exercise, while consuming carbohydrate or protein immediately before and during exercise attenuates this. We recommend using our dual sugar absorption test protocol to maximise intestinal epithelial permeability data collection in exercise gastroenterology research and beyond.

Clearance and production of ammonia quantified in humans by constant ammonia infusion - the effects of cirrhosis and ammonia-targeting treatments.

BACKGROUND & AIMS: Hyperammonaemia is a key pathological feature of liver disease and the primary driver of hepatic encephalopathy (HE). However, the relative roles of increased ammonia production and reduced clearance are poorly understood as is the action of ammonia-targeting drugs for HE. We aimed to quantify whole-body ammonia metabolism in healthy persons and patients with cirrhosis and to validate our method by examining the effects of glycerol phenylbutyrate and lactulose + rifaximin treatment. METHODS: Ten healthy men and ten male patients with cirrhosis were investigated by 90-minute constant ammonia infusion to achieve steady-state plasma ammonia. Whole-body ammonia clearance was calculated as infusion rate divided by steady-state concentration increase and ammonia production was calculated as clearance multiplied by baseline ammonia concentration. Participants were re-investigated after the ammonia-targeting interventions. RESULTS: In healthy persons, ammonia clearance was 3.5 (3.1-3.9) L/min and ammonia production was 49 (35-63) µmol/min. Phenylbutyrate increased clearance by 11% (4-19%, p = 0.009). In patients with cirrhosis, ammonia clearance was 20% lower at 2.7 (2.1-3.3) L/min (p = 0.02) and production was nearly threefold higher at 131 (102-159) µmol/min (p <0.0001). Lactulose + rifaximin reduced production by 20% (2-37%, p = 0.03). The infusion was generally well-tolerated apart from in one hyperammonaemic patient, with cirrhosis and possible bleeding unrelated to the infusion, who developed clinical HE that reverted when infusion was discontinued. CONCLUSIONS: Whole-body ammonia clearance and production may be measured separately using the described technique. This technique identified a lower clearance and a higher production of ammonia in patients with cirrhosis, and showed that phenylbutyrate increases clearance, whereas lactulose + rifaximin reduces production. IMPACT AND IMPLICATIONS: High blood ammonia plays a key role in cirrhosis-related brain dysfunction. However, the relative roles of reduced ammonia clearance and increased ammonia production are poorly understood as is the action of ammonia-targeting treatments. This study presents a relatively simple test to measure ammonia metabolism. By using this test, it was possible to show that patients with cirrhosis exhibit decreased ammonia clearance and increased ammonia production compared to healthy persons, and to quantify the unique effects of different ammonia-targeting treatments. The test described herein may be used to examine a range of questions related to normal physiology, pathophysiology and the mechanisms of action of ammonia-targeting treatments. CLINICAL TRIAL NUMBER: ClinicalTrials.gov (1-16-02-297-20).

Dosing of Rifaximin Soluble Solid Dispersion Tablets in Adults With Cirrhosis: 2 Randomized, Placebo-controlled Trials.

BACKGROUND & AIMS: Cirrhosis-related complications are a major burden. Rifaximin soluble solid dispersion (SSD) tablets (immediate-release [IR]; sustained extended-release [SER]) were designed to increase rifaximin water solubility. These analyses evaluate dosing for prevention of cirrhosis complication-related hospitalizations/mortality and overt hepatic encephalopathy (OHE) treatment. METHODS: Two phase II, randomized, double-blind, placebo-controlled trials were conducted. Trial 1: outpatients with early decompensated cirrhosis randomized to placebo or rifaximin SSD once-nightly: IR 40 or 80 mg, SER 40 or 80 mg, or IR 80 mg plus SER 80 mg, for 24 weeks. Trial 2: inpatients with OHE randomized to lactulose plus placebo or rifaximin SSD: IR 40 mg once or twice daily or SER 80 mg once or twice daily for ≤14 days. Primary efficacy endpoint: time to cirrhosis complication-related hospitalization/all-cause mortality (Trial 1) or time to OHE resolution (Trial 2). RESULTS: In Trial 1 (n = 516), no significant difference in time to cirrhosis complication-related hospitalization/all-cause mortality vs placebo. In a post hoc analysis, time to all-cause hospitalization/all-cause mortality was improved with IR 40 mg vs placebo (15.4% [12/78] vs 27.7% [26/94]; P = .03). A Trial 2 prespecified interim analysis (n = 71) showed lactulose plus rifaximin SSD IR 40 mg bid significantly reduced median time to OHE resolution (21.1 hours) vs lactulose plus placebo (62.7 hours; P = .02). Trial 2 was subsequently terminated. CONCLUSION: Rifaximin SSD IR 40 mg may reduce hospitalizations in patients with cirrhosis and shorten duration of OHE during hospitalization-considered a negative finding, yet also hypothesis-generating. (ClinicalTrials.govNCT01904409; NCT03515044).

Clinical Outcomes of Oral Zinc Therapy in Hepatic Encephalopathy Treatment.

BACKGROUND: Additional therapies for hepatic encephalopathy (HE) treatment are warranted. There are data evaluating the use of zinc for HE; however, clinical outcomes, specifically in the United States, are unknown. OBJECTIVE: To compare 30-day and 1-year all-cause readmission rates in patients with cirrhosis complicated by HE on lactulose and rifaximin to those on lactulose, rifaximin, and zinc. METHODS: This retrospective study included patients admitted with documented cirrhosis and home medications of lactulose and rifaximin, with or without zinc. Patients were stratified into 2 groups: those receiving lactulose and rifaximin for HE (control) and those receiving lactulose, rifaximin, and zinc for HE (treatment). The primary outcomes were 30-day and 1-year all-cause readmission rates. RESULTS: One-hundred fifty-seven patients were included (102 in control group, 55 in treatment group). Regarding 30-day and 1-year all-cause readmission rates, there was no difference between the control and treatment groups. CONCLUSION AND RELEVANCE: This is the first study conducted in the United States evaluating zinc for HE treatment. Zinc did not impact 30-day or 1-year all-cause readmission rates. Further studies are warranted to evaluate the potential benefit of zinc for HE, possibly in correlation with Model for End-stage Liver Disease-Sodium (MELD-Na) scores.

Barriers to Lactulose Adherence in Patients with Cirrhosis and Hepatic Encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) is a major cause of mortality and morbidity in patients with cirrhosis. Lactulose non-adherence is one of the most frequently reported precipitants of hospital admission for HE. AIMS: We aimed to identify which factors contribute most to lactulose non-adherence and propose strategies to promote greater adherence and utilization of lactulose. METHODS: Participants in this study consisted of patients with cirrhosis who were taking lactulose for prevention of HE. Subjects were administered the Morisky Adherence Scale 8 (MAS-8) and a customized 16-question survey that assessed barriers to lactulose adherence. Results from the MAS-8 were used to stratify subjects into "adherent" and "non-adherent" groups. Survey responses were compared between groups. RESULTS: We enrolled 129 patients in our study, of whom 45 were categorized as "adherent and 72 were categorized as "non-adherent." Barriers to adherence included large volumes of lactulose, high frequency of dosing, difficulty remembering to take the medication, unpleasant taste, and medication side-effects. Most patients (97%) expressed understanding of the importance of lactulose, and 71% of patients felt that lactulose was working to manage their HE. Hospital admission rates for HE was higher in non-adherent patients, although this difference was not statistically significant. CONCLUSION: We identified several factors that contribute to lactulose non-adherence among patients treated for HE. Many of these factors are potentially modifiable. Patient and care-giver education are critical to assure adherence. Pharmacists and nurses are an essential but underutilized aspect of education regarding proper medication use.

Hydrogen Availability Is Dependent on the Actions of Both Hydrogen-Producing and Hydrogen-Consuming Microbes.

Hydrogen gas (H2) is produced by H2-producing microbes in the gut during polysaccharide fermentation. Gut microbiome also includes H2-consuming microbes utilizing H2 for metabolism: methanogens producing methane, CH4, and sulfate-reducing bacteria producing hydrogen sulfide, H2S. H2S is not measured in the evaluation of gaseous byproducts of microbial fermentation. We hypothesize that the availability of measured H2 depends on both hydrogen producers and hydrogen consumers by measuring H2 in vitro and in vivo. In the in vitro study, groups were Bacteroides thetaiotaomicron (B. theta, H2 producers), Desulfovibrio vulgaris (D. vulgaris, H2 consumers), and D. vulgaris + B. theta combined. Gas samples were collected at 2 h and 24 h after incubation and assayed for H2, CH4, and H2S. In the in vivo study Sprague-Dawley rats were gavaged with suspended bacteria in four groups: B. theta, D. vulgaris, combined, and control. Gas was analyzed for H2 at 60 min. In the in vitro experiment, H2 concentration was higher in the combined group (188 ± 93.3 ppm) compared with D. vulgaris (27.17 ± 9.6 ppm) and B. theta groups (34.2 ± 29.8 ppm; P < 0.05); H2S concentration was statistically higher in the combined group (10.32 ± 1.5 ppm) compared with B. theta (0.19 ± 0.03 ppm) and D. vulgaris group (3.46 ± 0.28 ppm; P < 0.05). In the in vivo study, H2 concentrations were significantly higher in the B. theta group (44.3 ± 6.0 ppm) compared with control (31.8 ± 4.3) and the combined group (34.2 ± 8.7, P < 0.05). This study shows that sulfate-reducing bacteria could convert available H2 to H2S, leading to measured hydrogen levels that are dependent on the actions of both H2 producers and H2 consumers.

Use of lactulose as a prebiotic in laying hens: its effect on growth, egg production, egg quality, blood biochemistry, digestive enzymes, gene expression and intestinal morphology.

BACKGROUND: The rising popularity of eggs as an alternative source of protein to meat has led to significant increase in egg consumption over the past decade. To meet the increasing demand for eggs, poultry farmers have used antibiotics to treat infections and, to some extent, promote growth and egg production in raising layer. However, the emergence and global spread of antibiotic resistant bacteria has now necessitated antibiotic-free poultry farming. As alternatives to antibiotics, prebiotics are feed additives that can be used to improve the growth and laying performance of poultry which positively impacts their performance and general health. In this study we evaluated the effect of lactulose, formulated as Vetelact, on body weight, egg production, egg quality, blood biochemical parameters and expression of genes associated with reproductive performance in laying hens. RESULTS: Vetelact supplementation improved egg weight, egg production as well as egg quality. Following Vetalact supplementation, the levels of total bilirubin, total protein, globulin and phosphorus were increased, while the activities of alkaline phosphatase and lipase enzymes were increased compared to control. Vetelact at 0.10 ml/kg body weight upregulated OCX-36, OVAL, CALB1, OC-116, OCX-32 and IL8 transcripts while downregulating the transcription of Gal-10, PENK and AvBD9. At this optimal inclusion rate of Vetalect, histomorphologic analyses of intestinal tissue showed increased villi length with more goblet cell distribution and obvious mucus covering a surface, increase in the depth of intestinal crypts produce digestive enzymes, as well as more developed muscle layer that promote improved nutrient absorption. CONCLUSION: Vetelact at a dose of 0.10 ml/ kg body weight was effective in improving productive performance of laying hens. Adding lactulose (0.10 ml/ kg body weight) to layer diet is recommended to promote growth and improve egg laying performance in antibiotics-free poultry production.

Lactulose in combination with soybean lecithin has a cryoprotective effect on probiotic taxa of bifidobacteria and Lactobacillaceae.

Lactulose is commonly used in pharmacy for constipation and hepatic encephalopathy treatment. The prebiotic effect of lactulose is also often mentioned. However, its cryoprotective effect in combination with lecithin on the main representatives of probiotics has not been tested yet. The 12 taxa of bifidobacteria and Lactobacillaceae members were used for the purpose. These were mixed in a ratio of 1:1 with lactulose + lecithin (finally 5.0% and 1.25%, respectively; LL). The 25% glycerol (G+) solution and cultures themselves were applied as positive and negative controls, respectively. Bacterial suspensions were stored at a mild freezing temperature (-20°C) until the end of the experiment (210th day). The LL solution had a comparable (insignificant difference at the P-value = 0.05) cryoprotective effect as the positive control in five of six bifidobacteria and in three of six representatives of Lactobacillaceae. The better cryoprotective effect was revealed in other Lactobacillaceae. At the end of the experiment, the generally accepted therapeutic minimum (>107 Colony Forming Units/mL) was determined in LL solution in five bifidobacteria and four Lactobacillaceae strains. The presented results improve knowledge about long-term mild cryopreservation of the most commonly used probiotics and could contribute to developing new forms of (nutri)synbiotics.

Prevention of dextran sulfate sodium (DSS)-induced ulcerative colitis in mice by a synbiotic approach using probiotic and lactulose.

In this research, the synbiotic effects of the probiotic Lactiplantibacillus plantarum YW11 and lactulose on intestinal morphology, colon function, and immune activity were evaluated in a mouse model of UC induced by dextran sulfate sodium (DSS). The results revealed that L. plantarum YW11 in combination with lactulose decreased the severity of colitis in mice and improved the structure of the damaged colon, as assessed using colon length and disease condition. Moreover, colonic levels of pro-inflammatory cytokines (IL-1ß, IL-6, IL-12, TNF-α, and IFN-γ) were significantly lower and anti-inflammatory factors (IL-10) were significantly higher following the synbiotic supplementation. The synbiotic also exerted antioxidant effects by up-regulating SOD and CAT levels and down-regulating MDA levels in colon tissue. It could also reduce the relative expression of iNOS mRNA and increase the relative expression of nNOS and eNOS mRNA. Western blot confirmed the increased expression of c-Kit, IκBα, and SCF and significantly reduced expression of the NF-κB protein. Therefore, the combination of L. plantarum YW11 and lactulose exerted therapeutic effects mainly through the NF-κB anti-inflammatory pathway, which represented a novel synbiotic approach in the prevention of colonic inflammation.

Laser acupuncture improving functional chronic constipation in children: a randomized controlled trial.

Functional chronic constipation (FCC) is a disorder caused by low fiber consumption, lack of fluid intake, lack of mobility, or side effects of medications. The objective of this study was to compare the effects of laser acupuncture and the commonly used osmotic laxative, lactulose (as the control), both combined with behavioral therapy and dietary modification, on children with FCC in a randomized controlled trial (RCT). Forty children were randomly chosen, aged 5-15 years with FCC, and randomized into two equal groups (gender ratio (50% male; 50% female), mean ± SD weight (24.2 ± 6.27 kg and 25.7 ± 7.47 kg for groups A and B, respectively)). Study group (group A): used laser acupuncture (650 nm), 30 mW, 0.15 cm2 spot size, 90 s per acupuncture point (ST25, ST36, ST37, BL25, and LI11). Control group (group B): lactulose syrup (1 to 3 mL/kg/day) orally, in divided doses 3 times weekly for 4 weeks, and behavioral training for both groups. Evaluations were conducted before and after the study to assess the efficacy of the therapy. Median value frequency significantly increased in groups A and B post-treatment (4 (6.75-3) and 3 (3.75-2), respectively) compared to pre-treatment (2 (2-1) and 2 (2-0.25), respectively) (p = 0.0001), in favor of group A (p = 0.01). Significant improvement of stool consistency according to Bristol stool scale (BSS) in groups A and B (p = 0.0001), (p = 0.002) respectively in favor of group A (p = 0.03). T-test, Fisher, and Wilcoxon signed rank tests were conducted to compare groups. Non-invasive, painless laser acupuncture therapy can be considered as an alternative therapy for patients with FCC.

Computer-aided design of novel cellobiose 2-epimerase for efficient synthesis of lactulose using lactose.

Cellobiose 2-epimerase (CE) is ideally suited to synthesize lactulose from lactose, but the poor thermostability and catalytic efficiency restrict enzymatic application. Herein, a non-characterized CE originating from Caldicellulosiruptor morganii (CmCE) was discovered in the NCBI database. Then, a smart mutation library was constructed based on FoldX ΔΔG calculation and modeling structure analysis, from which a positive mutant D226G located within the α8/α9 loop exhibited longer half-lives at 65-75 °C as well as lower Km and higher kcat/Km values compared with CmCE. Molecular modeling demonstrated that the improvement of D226G was largely attributed to the rigidification of the flexible loop, the compactness of the catalysis pocket and the increment of substrate-binding capability. Finally, the yield of synthesizing lactulose catalyzed by D226G reached 45.5%, higher than the 35.9% achieved with CmCE. The disclosed effect of the flexible loop on enzymatic stability and catalysis provides insight to redesign efficient CEs to biosynthesize lactulose.

Effect of Malva neglecta and lactulose on survival of Lactobacillus fermentum and textural properties of synbiotic stirred yogurt.

Yogurt is a popular dairy product and its consumption has been progressively growing over the past few decades by raising consumers' health-consciousness. As yogurt is growing in popularity, manufacturers are continuously seeking for bioactive components such as probiotics and prebiotics, to produce functional yogurt with more beneficial health effects. Therefore, this study aimed to evaluate the effect of Malva neglecta (MN, 0, 5, 10 and 15%) and lactulose (0, 1 and 2%) as prebiotic substances on survival of Lactobacillus fermentum in a half-fat synbiotic stirred yogurt. The results revealed that with increasing MN and lactulose concentrations, the count of Lb. fermentum significantly increased (p < 0.05). At the end of 21-day cold storage, the count of probiotics in yogurt sample having 2% lactulose and 10-15% MN significantly was higher than control (8.37-8.4 vs. 7.73 Log cfu/g). With increasing the amount of MN and lactulose, firmness and chewiness of yogurt samples decreased while adhesiveness increased (p < 0.05). Scanning electron microscopy assessment shown that addition of MN and lactulose resulted in a higher moisture retention in the void spaces. The results revealed that by incorporating lactulose and MN in yogurt formulation, an appropriate synbiotic yogurt could be produced as a novel functional product.

Racial and ethnic disparities in rifaximin use and subspecialty referrals for patients with hepatic encephalopathy in the United States.

BACKGROUND & AIMS: Rifaximin use in combination with lactulose is associated with a decreased risk of overt hepatic encephalopathy (HE). We sought to determine whether race and ethnicity were associated with rifaximin prescriptions. METHODS: We examined data for a 20% random sample of United States Medicare enrollees with cirrhosis and hepatic encephalopathy treated with outpatient lactulose and Part D prescription coverage from 2011-2019. Beginning at the time of first diagnosis, we evaluated time to first prescription of rifaximin accounting for competing risks (Fine-Gray, yielding subdistribution hazard ratios [sHRs]) and cumulative rifaximin exposure using a gamma hurdle model (yielding exposure length ratios). We aimed to determine the association of race and ethnicity with each outcome, adjusting for demographics, clinical factors, and other features of clinical management. RESULTS: Overall, 29,095 patients were diagnosed with HE and treated with lactulose, of whom 13,272 were prescribed rifaximin. Compared to White patients, Black patients were least likely to receive any prescription for rifaximin (sHR 0.70; 95% CI 0.65-0.76). Asian and Hispanic patients were also less likely to receive rifaximin compared to White patients. Black patients also received fewer doses of rifaximin (exposure length ratio 0.90; 95% CI 0.82-0.98). Hispanic patients also received fewer doses (0.88; 95% CI 0.80-0.98). Out-of-pocket spending on rifaximin per person-year was higher for Black and Hispanic than White patients. Out-of-pocket medication spending was associated with reduced odds of filling a rifaximin prescription. Black and Hispanic patients were least likely to be referred to a gastroenterologist. CONCLUSION: In a national cohort of patients with HE, we observed stark racial and ethnic disparities in the use of rifaximin, an approved therapy for the improvement of HE-specific outcomes. Access to gastroenterologists and cost controls may reduce disparities. LAY SUMMARY: Hepatic encephalopathy is a serious problem that can affect people with cirrhosis. When someone develops hepatic encephalopathy, there are 2 main treatments. The first-line treatment is called lactulose. If episodes of hepatic encephalopathy happen on lactulose, another treatment called rifaximin is recommended. In this study, we found that compared to White patients, Black and Hispanic patients are less likely to be prescribed rifaximin, receive fewer rifaximin refills, spend more on rifaximin, and have less access to subspecialists who are familiar with rifaximin. We conclude that efforts to address the cost of rifaximin and access to gastroenterologists could help improve these disparities.

Heretical thoughts into hepatic encephalopathy.

Clinical progress in the development of new diagnostic modalities and therapeutic strategies for the management of patients with hepatic encephalopathy has lagged behind the vast knowledge that has been generated from basic studies. In this article, we critically assess matters that should be revisited, such as definition, classification, diagnosis and grading of hepatic encephalopathy, which are difficult to apply reproducibly using the current criteria. Many lines of investigation have confirmed that hepatic encephalopathy is irreversible in many patients and suggest the need for further studies focussing on mechanisms of neuronal injury and death, to guide future drug development for these patients. The clinical evidence behind using lactulose for all severities of hepatic encephalopathy, which is currently considered the standard of care, is poor and placebo-controlled trials for hepatic encephalopathy should be considered ethically sound. This expert opinion identifies current challenges in hepatic encephalopathy and highlights areas which require further debate and investigation in order to help advance the field both scientifically and clinically.

Development and Validation of Test for "Leaky Gut" Small Intestinal and Colonic Permeability Using Sugars in Healthy Adults.

BACKGROUND: Oral monosaccharides and disaccharides are used to measure in vivo human gut permeability through urinary excretion. AIMS: The aims were as follows: (1) to obtain normative data on small intestinal and colonic permeability; (2) to assess variance on standard 16 g fiber diet performed twice; (3) to determine whether dietary fiber influences gut permeability measurements; and (4) to present pilot data using 2 selected probes in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). METHODS: Sixty healthy female and male adults, age 18-70 years, participated in 3 randomized studies (2 studies on 16.25 g and 1 study on 32.5 g fiber) in otherwise standardized diets. At each test, the following sugars were ingested: 12C-mannitol, 13C-mannitol, rhamnose (monosaccharides), sucralose, and lactulose (disaccharides). Standardized meals were administered from 24 hours before and during 24 hours post-sugars with 3 urine collections: 0-2, 2-8, and 8-24 hours. Sugars were measured using high-performance liquid chromatography-tandem mass spectrometry. Eighteen patients with IBS-D underwent 24-hour excretion studies after oral 13C-mannitol and lactulose. RESULTS: Baseline sugars (>3-fold above lower limits of quantitation) were identified in the 3 studies: 12C-mannitol in all participants; sucralose in 4-8, and rhamnose in 1-3. Median excretions/24 h (percentage of administered dose) for 13C-mannitol, rhamnose, lactulose, and sucralose were ∼30%, ∼15%, 0.32%, and 2.3%, respectively. 13C-mannitol and rhamnose reflected mainly small intestinal permeability. Intraindividual saccharide excretions were consistent, with minor differences with 16.25 g vs 32.5 g fiber diets. Median interindividual coefficient of variation was 76.5% (10-90 percentile: 34.6-111.0). There were no significant effects of sex, age, or body mass index on permeability measurements in health. 13C-mannitol measurements are feasible in IBS-D. CONCLUSIONS: Baseline 12C-mannitol excretion precludes its use; 13C-mannitol is the preferred probe for small intestinal permeability.

A case for improved assessment of gut permeability: a meta-analysis quantifying the lactulose:mannitol ratio in coeliac and Crohn's disease.

BACKGROUND: A widely used method in assessing small bowel permeability is the lactulose:mannitol test, where the lactulose:mannitol ratio (LMR) is measured. However, there is discrepancy in how the test is conducted and in the values of LMR obtained across studies. This meta-analysis aims to determine LMR in healthy subjects, coeliac and Crohn's disease. METHODS: A literature search was performed using PRISMA guidance to identify studies assessing LMR in coeliac or Crohn's disease. 19 studies included in the meta-analysis measured gut permeability in coeliac disease, 17 studies in Crohn's disease. Outcomes of interest were LMR values and comparisons of standard mean difference (SMD) and weighted mean difference (WMD) in healthy controls, inactive Crohn's, active Crohn's, treated coeliac and untreated coeliac. Pooled estimates of differences in LMR were calculated using the random effects model. RESULTS: Pooled LMR in healthy controls was 0.014 (95% CI: 0.006-0.022) while pooled LMRs in untreated and treated coeliac were 0.133 (95% CI: 0.089-0.178) and 0.037 (95% CI: 0.019-0.055). In active and inactive Crohn's disease, pooled LMRs were 0.093 (95% CI: 0.031-0.156) and 0.028 (95% CI: 0.015-0.041). Significant differences were observed in LMR between: (1) healthy controls and treated coeliacs (SMD = 0.409 95% CI 0.034 to 0.783, p = 0.032), (2) healthy controls and untreated coeliacs (SMD = 1.362 95% CI: 0.740 to 1.984, p < 0.001), (3) treated coeliacs and untreated coeliacs (SMD = 0.722 95% CI: 0.286 to 1.157, p = 0.001), (4) healthy controls and inactive Crohn's (SMD = 1.265 95% CI: 0.845 to 1.686, p < 0.001), (5) healthy controls and active Crohn's (SMD = 2.868 95% CI: 2.112 to 3.623, p < 0.001), and (6) active Crohn's and inactive Crohn's (SMD = 1.429 (95% CI: 0.580 to 2.278, p = 0.001). High heterogeneity was observed, which was attributed to variability in protocols used across different studies. CONCLUSION: The use of gut permeability measurements in screening and monitoring of coeliac and Crohn's disease is promising. LMR is useful in performing this function with significant limitations. More robust alternative tests with higher degrees of clinical evidence are needed if measurements of gut permeability are to find widespread clinical use.

Effects of oral cystine and glutamine on exercise-induced changes in gastrointestinal permeability and damage markers in young men.

PURPOSE: Although acute prolonged strenuous exercise has been shown to increase markers of gastrointestinal permeability and damage, little is known regarding the efficacy of nutritional supplement interventions on the attenuation of exercise-induced gastrointestinal syndrome. This study addressed the effects of oral amino acid supplementation on markers of gastrointestinal permeability and damage in response to exercise. METHODS: Sixteen active men aged 22.7 ± 2.6 years (mean ± standard deviation) completed placebo or cystine and glutamine supplementation trials in random order. Participants received either a placebo or cystine and glutamine supplements, three times a day for 5 days, separated by a 2-week washout period. On day 6, participants took their designated supplements 30 min before running at a speed corresponding to 75% of maximal oxygen uptake for 1 h, followed by a 4-h rest period. Blood samples were collected pre-exercise, immediately post-exercise, 30 min post-exercise, and 1, 2 and 4 h post-exercise on day 6. The plasma lactulose to mannitol ratio (L:M) and plasma intestinal fatty acid-binding protein (I-FABP) were used as markers of gastrointestinal permeability and damage, respectively. RESULTS: Plasma L:M (linear mixed model, coefficient ± standard error: - 0.011 ± 0.004, P = 0.0090) and changes (i.e., from pre-exercise) in plasma I-FABP (linear mixed model, - 195.3 ± 65.7 coefficient ± standard error (pg/mL), P = 0.0035) were lower in the cystine and glutamine supplementation trial than in the placebo trial. CONCLUSION: Oral cystine and glutamine supplementation attenuated the markers of gastrointestinal permeability and damage after 1 h of strenuous running in young men. TRIAL REGISTRATION NUMBER: UMIN000026008. DATE OF REGISTRATION: 13 December 2018.

Use of Lactulose to Treat Hyperammonemia in ICU Patients Without Chronic Liver Disease or Significant Hepatocellular Injury.

OBJECTIVES: To review ICU patients with elevated ammonia without a clear hepatic etiology, to compare outcomes between those who received lactulose and those who did not. DESIGN: Retrospective observational study. SETTING: Medical, surgical, and subspecialty intensive care units at Wake Forest Baptist Medical Center, Winston-Salem, North Carolina between December 2012 and August 2016. PATIENTS: Adults with ammonia levels above 50 µmol/L, excluding those with known chronic liver disease, inborn error of metabolism, active use of valproic acid, total bilirubin ≥ 2 µmol/L, or alanine aminotransferase ≥ 100 units/L. INTERVENTIONS: Comparison in ICU length of stay (LOS), hospital LOS, in-hospital mortality, and mortality at 30 and 90 days. MEASUREMENTS AND MAIN RESULTS: Criteria for inclusion were met in 103 cases. Mean ammonia level was 75 µmol/L, with undetermined etiology in the majority of subjects. Lactulose was given in 48 cases (46.6%), with a median of 9.5 doses given. There were no significant differences in outcomes between the lactulose and non-lactulose groups. Among subjects with multiple data points, lactulose did not have a dose-dependent effect on ammonia level, and was not associated with faster ammonia normalization compared to non-lactulose. When analyzed separately, patients with moderate hyperammonemia (60-99 µmol/L) who received lactulose had longer hospital and ICU length of stay compared to non-lactulose (417.8 hours vs. 208.4 hours, P = 0.003, and 229.2 hours vs. 104.7 hours, P = 0.025; respectively), though confounders were present. CONCLUSIONS: Routine use of lactulose to treat mild to moderate hyperammonemia in this patient population was not associated with improved outcomes.