Rifaximin-α for liver fibrosis in patients with alcohol-related liver disease (GALA-RIF): a randomised, double-blind, placebo-controlled, phase 2 trial

Digestive dynamics: Unveiling interplay between the gut microbiota and the liver in macronutrient metabolism and hepatic metabolic health

Although the liver is the largest metabolic organ in the body, it is not alone in functionality and is assisted by "an organ inside an organ," the gut microbiota. This review attempts to shed light on the partnership between the liver and the gut microbiota in the metabolism of macronutrients (i.e., proteins, carbohydrates, and lipids). All nutrients absorbed by the small intestines are delivered to the liver for further metabolism. Undigested food that enters the colon is metabolized further by the gut microbiota that produces secondary metabolites, which are absorbed into portal circulation and reach the liver. These microbiota-derived metabolites and co-metabolites include ammonia, hydrogen sulfide, short-chain fatty acids, secondary bile acids, and trimethylamine N-oxide. Further, the liver produces several compounds, such as bile acids that can alter the gut microbial composition, which can in turn influence liver health. This review focuses on the metabolism of these microbiota metabolites and their influence on host physiology. Furthermore, the review briefly delineates the effect of the portosystemic shunt on the gut microbiota-liver axis, and current understanding of the treatments to target the gut microbiota-liver axis.

Antibiotics With or Without Rifaximin for Acute Hepatic Encephalopathy in Critically Ill Patients With Cirrhosis: A Double-Blind, Randomized Controlled (ARiE) Trial

INTRODUCTION

Critically ill patients with cirrhosis admitted to the intensive care unit (ICU) are usually on broad-spectrum antibiotics because of suspected infection or as a hospital protocol. It is unclear if additional rifaximin has any synergistic effect with broad-spectrum antibiotics in ICU patients with acute overt hepatic encephalopathy (HE).

METHODS

In this double-blind trial, patients with overt HE admitted to ICU were randomized to receive antibiotics (ab) alone or antibiotics with rifaximin (ab + r). Resolution (or 2 grade reduction) of HE, time to resolution of HE, in-hospital mortality, nosocomial infection, and changes in endotoxin levels were compared between the 2 groups. A subgroup analysis of patients with decompensated cirrhosis and acute-on-chronic liver failure was performed.

RESULTS

Baseline characteristics and severity scores were similar among both groups (92 in each group). Carbapenems and cephalosporin with beta-lactamase inhibitors were the most commonly used ab. On Kaplan-Meier analysis, 44.6% (41/92; 95% confidence interval [CI], 32-70.5) in ab-only arm and 46.7% (43/92; 95% CI, 33.8-63) in ab + r arm achieved the primary objective ( P = 0.84).Time to achieve the primary objective (3.65 ± 1.82 days and 4.11 ± 2.01 days; P = 0.27) and in-hospital mortality were similar among both groups (62% vs 50%; P = 0.13). Seven percent and 13% in the ab and ab + r groups developed nosocomial infections ( P = 0.21). Endotoxin levels were unaffected by rifaximin. Rifaximin led to lower in-hospital mortality (hazard ratio: 0.39 [95% CI, 0.2-0.76]) in patients with decompensated cirrhosis but not in patients with acute-on-chronic liver failure (hazard ratio: 0.99 [95% CI, 0.6-1.63]) because of reduced nosocomial infections.

DISCUSSION

Reversal of overt HE in those on ab was comparable with those on ab + r.

Gut-liver axis: Recent concepts in pathophysiology in alcohol-associated liver disease

The growing recognition of the role of the gut microbiome's impact on alcohol-associated diseases, especially in alcohol-associated liver disease, emphasizes the need to understand molecular mechanisms involved in governing organ-organ communication to identify novel avenues to combat alcohol-associated diseases. The gut-liver axis refers to the bidirectional communication and interaction between the gut and the liver. Intestinal microbiota plays a pivotal role in maintaining homeostasis within the gut-liver axis, and this axis plays a significant role in alcohol-associated liver disease. The intricate communication between intestine and liver involves communication between multiple cellular components in each organ that enable them to carry out their physiological functions. In this review, we focus on novel approaches to understanding how chronic alcohol exposure impacts the microbiome and individual cells within the liver and intestine, as well as the impact of ethanol on the molecular machinery required for intraorgan and interorgan communication.

H2S-driven chemotherapy and mild photothermal therapy induced mitochondrial reprogramming to promote cuproptosis

The elevated level of hydrogen sulfide (H2S) in colon cancer hinders complete cure with a single therapy. However, excessive H2S also offers a treatment target. A multifunctional cascade bioreactor based on the H2S-responsive mesoporous Cu2Cl(OH)3-loaded hypoxic prodrug tirapazamine (TPZ), in which the outer layer was coated with hyaluronic acid (HA) to form TPZ@Cu2Cl(OH)3-HA (TCuH) nanoparticles (NPs), demonstrated a synergistic antitumor effect through combining the H2S-driven cuproptosis and mild photothermal therapy. The HA coating endowed the NPs with targeting delivery to enhance drug accumulation in the tumor tissue. The presence of both the high level of H2S and the near-infrared II (NIR II) irradiation achieved the in situ generation of photothermic agent copper sulfide (Cu9S8) from the TCuH, followed with the release of TPZ. The depletion of H2S stimulated consumption of oxygen, resulting in hypoxic state and mitochondrial reprogramming. The hypoxic state activated prodrug TPZ to activated TPZ (TPZ-ed) for chemotherapy in turn. Furthermore, the exacerbated hypoxia inhibited the synthesis of adenosine triphosphate, decreasing expression of heat shock proteins and subsequently improving the photothermal therapy. The enriched Cu2+ induced not only cuproptosis by promoting lipoacylated dihydrolipoamide S-acetyltransferase (DLAT) heteromerization but also performed chemodynamic therapy though catalyzing H2O2 to produce highly toxic hydroxyl radicals ·OH. Therefore, the nanoparticles TCuH offer a versatile platform to exert copper-related synergistic antitumor therapy.

Non-invasive tests for alcohol-associated liver disease

Alcohol consumption is a global phenomenon and a major contributor to alcohol-associated liver disease (ALD). Detecting individuals at risk of ALD has been challenging, with only a small fraction of patients being identified at early stages compared to other chronic liver diseases. In response to this challenge, non-invasive tests (NITs) have become essential tools for the detection of ALD, offering opportunities for early identification and intervention to mitigate the disease burden. Noninvasive alcohol consumption biomarkers are crucial in estimating individuals' recent alcohol intake, providing valuable insights into their drinking patterns. Various NITs have been investigated for the initial screening of asymptomatic individuals at risk of ALD, as well as for identifying specific stages of the disease. These NITs are applied in 2 main clinical scenarios: population-based stratification for identifying and predicting liver-related symptoms and diagnosing and prognosticating compensated cirrhosis or advanced chronic liver disease in secondary or tertiary care settings. Moreover, NITs play a significant role in the prognostic assessment of patients with various manifestations of ALD, including alcohol-associated hepatitis (AH), decompensated cirrhosis, and metabolic-associated and ALD. These tests guide appropriate treatment decisions and predict outcomes. In this review, various NITs for the early detection and monitoring of alcohol consumption were discussed. Additionally, the evaluation of NITs for screening and predicting ALD and liver complications was addressed comprehensively. Future perspectives of NITs for ALD were explored, alongside a thorough discussion of the opportunities and challenges associated with NITs for ALD screening.

Preventive and therapeutic effects of rifaximin on hepatic encephalopathy with differential application dosages and strategies: a network meta-analysis

BACKGROUND

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that affects the prognosis of patients with liver disease and is considered an independent risk factor for hospitalization and death. Rifaximin has been approved for HE treatment. This review will analyze the effect of rifaximin on different stages of HE with differential application dosages and strategies by traditional and network meta-analyses.

METHODS

We performed a systematic search of PubMed, EmBase, and Cochrane Library databases up to February 26, 2023, to identify randomized controlled trials (RCTs) about rifaximin for the prevention and treatment of HE. The outcomes included incidence of HE and HE progression, HE reversal, mortality, and adverse effects.

RESULTS

A total of 21 studies were included. In the primary prevention of HE, rifaximin significantly reduced the incidence of HE (OR: 0.66; 95% CI: 0.45, 0.96; p = 0.032). In secondary prevention, rifaximin significantly reduced the risk of recurrence in patients who were in remission (OR: 0.38; 95% CI: 0.28, 0.52; p < 0.001). In the treatment of minimal HE, rifaximin significantly reduced the breakthrough of MHE to OHE (OR: 0.17; 95% CI: 0.04,0.63; p = 0.008). Rifaximin also significantly improved the clinical symptoms of MHE and OHE patients (OR: 3.76; 95% CI: 2.69, 5.25; p < 0.001). However, rifaximin did not reduce mortality at any stage in HE patients (OR: 0.79; 95% CI: 0.58, 1.08; p = 0.133). Additionally, rifaximin did not increase the risk of adverse effects (OR: 0.96; 95% CI: 0.74, 1.24; p = 0.749). In the network meta-analysis, the 400 mg T.I.D. intervention had a relative advantage for HE risks in primary and secondary prevention. In the treatment of MHE, 600 mg b.i.d. was superior in preventing the breakthrough from MHE to OHE.

CONCLUSION

Rifaximin prevented HE risks and progression and improved clinical symptoms in patients with MHE but did not reduce mortality. For primary and secondary prevention, 400 mg t.i.d. could be considered. 600 mg b.i.d. could be considered in patients with MHE.

Validation of the new nomenclature of steatotic liver disease in patients with a history of excessive alcohol intake: an analysis of data from a prospective cohort study

BACKGROUND

Steatotic liver disease is a new overarching term that includes metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction and alcohol-related steatotic liver disease (MetALD), and alcohol-related liver disease (ALD). We aimed to validate the prognostic importance of MASLD, MetALD, and ALD as steatotic liver disease subclasses.

METHODS

Between April 18, 2013, and Sept 17, 2018, we prospectively recruited patients aged 18-75 years with current or previous excessive alcohol intake (>24 g/day for women and >36 g/day for men) for at least a year and no previous hepatic decompensation from the Department of Gastroenterology and Hepatology at Odense University Hospital (Odense, Denmark). Participants were followed up until Sept 15, 2022. Here, we characterise these patients according to steatotic liver disease subclasses. We classified patients as having MASLD, MetALD, or ALD in accordance with the nomenclature definitions, on the basis of metabolic comorbidity and self-reported average alcohol intake in the 3 months leading up to inclusion. Histological scoring was done by a pathologist who was masked to the clinical data. We compared prognoses between classes using Cox regression analyses on hepatic decompensation and overall mortality as the two outcome measures. Patients not meeting the criteria for steatotic liver disease were classified as no steatotic liver disease and served as a reference group.

FINDINGS

We enrolled 446 patients with a history of excessive alcohol intake were included in this analysis (334 [75%] were male and 112 [25%] were female; median age 56 years [SD 10]). Cirrhosis was present in 58 (13%), and 435 (98%) had at least one cardiometabolic risk factor. 321 (72%) met steatotic liver disease criteria and 125 (28%) did not have steatotic liver disease, meaning no evident liver steatosis and no significant fibrosis (≥F2). Of the 321 patients with steatotic liver disease, six (2%) were identified as having ALD due to the absence of cardiometabolic risk factors. The remaining 315 (98%) patients presented with at least one cardiometabolic risk factor. Of these patients, 153 (49%) had MASLD, 76 (24%) had MetALD, and 86 (27%) had ALD. During follow-up, 67 (15%) of 446 patients decompensated and 97 (22%) died (median follow-up 70 months [IQR 53-94]). Patients with steatotic liver disease had a significantly higher risk of hepatic decompensation and overall mortality than those without steatotic liver disease, independent of age, sex, and liver stiffness. The risk of decompensation increased in a stepwise manner from MASLD (hazard ratio 4·73 [95% CI 1·03-21·6]), through MetALD (7·69 [1·66-35·6]), to ALD (10·2 [2·24-46·4]). Similarly, overall mortality increased from MASLD (HR 2·30 [95% CI 1·08-4·90]), through MetALD (2·94 [1·31-6·58]), to ALD (3·57 [1·64-7·80]), independent of age, sex, and liver stiffness.

INTERPRETATION

Steatotic liver disease and its subclasses portend distinct prognoses. There is a need to specify how historical alcohol intake should be integrated into the nomenclature and risk stratification of steatotic liver disease.

FUNDING

EU Horizon 2020 Research and Innovation Program.

Acute and non-acute decompensation of liver cirrhosis (47/130)

In the traditional view, the occurrence of cirrhosis-related complications, such as hepatic encephalopathy, formation of ascites or variceal haemorrhage, marks the transition to the decompensated stage of cirrhosis. Although the dichotomous stratification into a compensated and decompensated state reflects a prognostic water-shed moment and remains to hold its prognostic validity, it represents an oversimplification of clinical realities. A broadening understanding of pathophysiological mechanisms underpinning decompensation have led to the identification of distinct prognostic subgroups, associated with different clinical courses following decompensation. Data provided by the PREDICT study uncovered three distinct sub-phenotypes of acute decompensation (AD). Moreover, acute-on-chronic liver failure (ACLF) has been established as a distinct clinical entity for many years, which is associated with a high short-term mortality. Recently, non-acute decompensation (NAD) has been proposed as a distinct pathway of decompensation, complementing current concepts of the spectrum of decompensation. In contrast to AD, NAD is characterized by a slow and progressive development of complications, which are often presented at first decompensation and/or in patients in an earlier stage of chronic liver disease. Successful treatment of AD or NAD may lead to a clinical stabilization or even the concept of recompensation. This review aims to provide an overview on current concepts of decompensation and to delineate recent advances in our clinical and pathophysiological understanding.

Exploring the Relationship between Liver Disease, Bacterial Translocation, and Dysbiosis: Unveiling the Gut-Liver Axis

Background

The global burden of liver disease and cirrhosis has been progressively increasing in the last decade. The interplay between gut microbiota and immune system and the bidirectional relationship with the liver, known as the gut-liver axis, has arisen as a fundamental aspect of liver disease.

Summary

Alterations of the gut microbiome have been described and include both dysbiotic microbial signatures and intestinal bacterial overgrowth. The integrity of the intestinal epithelial barrier is essential for preventing the access of harmful substances and bacterial products into the host. Bacterial translocation due to altered host-microbiota interactions triggers local immune cell activation and facilitates a chronic inflammatory state that can ultimately lead to immune exhaustion, characteristic of cirrhosis. In cirrhosis, breakdown of the gut vascular barrier allows access of bacterial products to portal blood circulation and facilitates their influx into the liver, further contributing to disease progression.

Key Messages

A better understanding of the contributing factors to pathological bacterial translocation and the impact of dysbiosis in liver disease will lead to achieve innovative therapeutic strategies in cirrhosis.

Therapeutic potential of stem cells in regeneration of liver in chronic liver diseases: Current perspectives and future challenges

The deposition of extracellular matrix and hyperplasia of connective tissue characterizes chronic liver disease called hepatic fibrosis. Progression of hepatic fibrosis may lead to hepatocellular carcinoma. At this stage, only liver transplantation is a viable option. However, the number of possible liver donors is less than the number of patients needing transplantation. Consequently, alternative cell therapies based on non-stem cells (e.g., fibroblasts, chondrocytes, keratinocytes, and hepatocytes) therapy may be able to postpone hepatic disease, but they are often ineffective. Thus, novel stem cell-based therapeutics might be potentially important cutting-edge approaches for treating liver diseases and reducing patient' suffering. Several signaling pathways provide targets for stem cell interventions. These include pathways such as TGF-β, STAT3/BCL-2, NADPH oxidase, Raf/MEK/ERK, Notch, and Wnt/β-catenin. Moreover, mesenchymal stem cells (MSCs) stimulate interleukin (IL)-10, which inhibits T-cells and converts M1 macrophages into M2 macrophages, producing an anti-inflammatory environment. Furthermore, it inhibits the action of CD4+ and CD8+ T cells and reduces the activity of TNF-α and interferon cytokines by enhancing IL-4 synthesis. Consequently, the immunomodulatory and anti-inflammatory capabilities of MSCs make them an attractive therapeutic approach. Importantly, MSCs can inhibit the activation of hepatic stellate cells, causing their apoptosis and subsequent promotion of hepatocyte proliferation, thereby replacing dead hepatocytes and reducing liver fibrosis. This review discusses the multidimensional therapeutic role of stem cells as cell-based therapeutics in liver fibrosis.

The potential for development of clinically relevant microbial resistance to rifaximin-α: a narrative review

Rifaximin-α is a gut-targeted antibiotic indicated for numerous gastrointestinal and liver diseases. Its multifaceted mechanism of action goes beyond direct antimicrobial effects, including alterations in bacterial virulence, cytoprotective effects on host epithelial cells, improvement of impaired intestinal permeability, and reduction of proinflammatory cytokine expression via activation of the pregnane X receptor. Rifaximin-α is virtually non-absorbed, with low systemic drug levels contributing to its excellent safety profile. While there are high concentrations of drug in the colon, low water solubility leads to low colonic drug bioavailability, protecting the gut microbiome. Rifaximin-α appears to be more active in the bile-rich small bowel. Its important biologic effects are largely at sub-inhibitory concentration. Although in vitro testing of clinical isolates from rifaximin recipients has revealed rifaximin-resistant strains in some studies, the risk of emergent rifaximin-α resistance appears to be lower than for many other antibiotics. Rifaximin-α has been used for many years for traveler's diarrhea with no apparent increase in resistance levels in causative pathogens. Further, rifaximin-α retains its efficacy after long-term and recurrent usage in chronic gastrointestinal disorders. There are numerous reasons why the risk of microbial resistance to rifaximin-α may be lower than that for other agents, including low intestinal bioavailability in the aqueous colon, the mechanisms of action of rifaximin-α not requiring inhibitory concentrations of drug, and the low risk of cross transmission of rifaximin-α resistance between bacterial species. Reported emergence of vancomycin-resistant Enterococcus in liver-disease patients maintained on rifaximin needs to be actively studied. Further studies are required to assess the possible correlation between in vitro resistance and rifaximin-α efficacy.

Binge drinking episode causes acute, specific alterations in systemic and hepatic inflammation-related markers

BACKGROUND

Frequent binge drinking is a known contributor to alcohol-related harm, but its impact on systemic and hepatic inflammation is not fully understood. We hypothesize that changes in immune markers play a central role in adverse effects of acute alcohol intake, especially in patients with early liver disease.

AIM

To investigate the effects of acute alcohol intoxication on inflammation-related markers in hepatic and systemic venous plasma in people with alcohol-related liver disease (ArLD), non-alcoholic fatty liver disease (NAFLD) and healthy controls.

METHODS

Thirty-eight participants (13 with ArLD, 15 with NAFLD and 10 healthy controls) received 2.5 mL of 40% ethanol per kg body weight via a nasogastric tube. Seventy-two inflammation-related markers were quantified in plasma from hepatic and systemic venous blood, at baseline, 60 and 180 min after intervention.

RESULTS

Alcohol intervention altered the levels of 31 of 72 and 14 of 72 markers in the systemic and hepatic circulation. All changes observed in the hepatic circulation were also identified in the systemic circulation after 180 min. Only FGF21 and IL6 were increased after alcohol intervention, while the remaining 29 markers decreased. Differences in response to acute alcohol between the groups were observed for 8 markers, and FGF21 response was blunted in individuals with steatosis.

CONCLUSION

Acute alcohol intoxication induced changes in multiple inflammation-related markers, implicated in alcohol metabolism and hepatocellular damage. Differences identified between marker response to binge drinking in ArLD, NAFLD and healthy controls may provide important clues to disease mechanisms and potential targets for treatment.

CLINICAL TRIAL NUMBER

NCT03018990.

Advances in the understanding and management of alcohol-related liver disease

Alcohol-related liver disease (ALD) is a major cause of liver-related morbidity and mortality. Epidemiological trends indicate recent and predicted increases in the burden of disease. Disease progression is driven by continued alcohol exposure on a background of genetic predisposition together with environmental cofactors. Most individuals present with advanced disease despite a long history of excessive alcohol consumption and multiple missed opportunities to intervene. Increasing evidence supports the use of non-invasive tests to screen for and identify disease at earlier stages. There is a definite role for public health measures to reduce the overall burden of disease. At an individual level, however, the ability to influence subsequent disease course by modifying alcohol consumption or the underlying pathogenic mechanisms remains limited due to a comparative lack of effective, disease-modifying medical interventions. Abstinence from alcohol is the key determinant of outcome in established ALD and the cornerstone of clinical management. In those with decompensated ALD, liver transplant has a clear role. There is consensus that abstinence from alcohol for an arbitrary period should not be the sole determinant in a decision to transplant. An increasing understanding of the mechanisms by which alcohol causes liver disease in susceptible individuals offers the prospect of new therapeutic targets for disease-modifying drugs. Successful translation will require significant public and private investment in a disease area which has traditionally been underfunded when compared to its overall prevalence.

Rifaximin Alfa and Liver Diseases: More Than a Treatment for Encephalopathy, a Disease Modifier

RFX, a rifamycin-based antibacterial agent obtained by the culture of the actinomycete Streptomyces mediterranei, has a broad antibacterial spectrum covering gram- positive, gram-negative, aerobic, and anaerobic bacteria. RFX is an antibiotic that elicits its effect by inhibiting bacterial RNA synthesis. When administered orally, its intestinal absorption is extremely low (<0.4%), restricting antibacterial activity mainly in the intestinal tract, with few systemic side effects. RFX has been recommended by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver guidelines for the treatment of HE. RFX may contribute to restore hepatic function and to decrease the development of liver fibrosis. Its efficacy has been shown in patients with previous hepatic encephalopathy and several complications, such as infections, including spontaneous bacterial peritonitis, ascites and oesophageal variceal bleeding. Thus, RFX has an outstanding role in the therapeutic arsenal in hepatic cirrhosis, under the concept of disease modifier.

Steatotic Liver Disease: Metabolic Dysfunction, Alcohol, or Both?

Non-alcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD), both of them accounting for fatty liver disease (FLD), are among the most common chronic liver diseases globally, contributing to substantial public health burden. Both NAFLD and ALD share a similar picture of clinical presentation yet may have differences in prognosis and treatment, which renders early and accurate diagnosis difficult but necessary. While NAFLD is the fastest increasing chronic liver disease, the prevalence of ALD has seemingly remained stable in recent years. Lately, the term steatotic liver disease (SLD) has been introduced, replacing FLD to reduce stigma. SLD represents an overarching term to primarily comprise metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), as well as alcohol-related liver disease (ALD), and MetALD, defined as a continuum across which the contribution of MASLD and ALD varies. The present review discusses current knowledge on common denominators of NAFLD/MASLD and ALD in order to highlight clinical and research needs to improve our understanding of SLD.

Probiotics, prebiotics, and synbiotics in nonalcoholic fatty liver disease and alcohol-associated liver disease

The use of probiotics, prebiotics, and synbiotics has become an important therapy in numerous gastrointestinal diseases in recent years. Modifying the gut microbiota, this therapeutic approach helps to restore a healthy microbiome. Nonalcoholic fatty liver disease and alcohol-associated liver disease are among the leading causes of chronic liver disease worldwide. A disrupted intestinal barrier, microbial translocation, and an altered gut microbiome metabolism, or metabolome, are crucial in the pathogenesis of these chronic liver diseases. As pro-, pre-, and synbiotics modulate these targets, they were identified as possible new treatment options for liver disease. In this review, we highlight the current findings on clinical and mechanistic effects of this therapeutic approach in nonalcoholic fatty liver disease and alcohol-associated liver disease.