Pharmacology of ursodeoxycholic acid, an enterohepatic drug

The effects of ursodeoxycholic acid on Parkinson's disease, a mechanistic review of the recent evidence

INTRODUCTION

Parkinson`s disease stands as the second-most widespread neurodegenerative disorder. Parkinson`s disease is relentless in progression and irreversible in nature, for which there is no cure. Therapies are only used to attenuate motor symptoms. As Parkinson`s disease is primarily defined by degeneration of dopaminergic neurons in the substantia nigra, and considering that neuroinflammation and mitochondrial dysfunction in these neurons are key factors contributing to disease progression, alternative therapies should aim to preserve healthy mitochondria. Method. Eligible studies on the effect of Ursodeoxycholic acid (UDCA) on Parkinson`s disease were collected from PubMed, Google Scholar, Scopus, Web of Science and Cochrane library for clinical, in-vivo, and in-vitro studies. Result. UDCA and its taurine conjugate (TUDCA), which are endogenous bile acids, have exhibited neuroprotective potential in various neurological conditions, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, in both animal experimental models and clinical investigations. This is attributed to three significant properties, in addition to their capability to cross the blood-brain barrier. First, their anti-inflammatory properties are manifested through the reduction of significant inflammatory factors such as tumor necrosis factor-α, interleukin 1β and other related elements. Second, their antioxidant property is marked by an increase in the expression of superoxide dismuthase, glutathione peroxidase and other antioxidant enzymes. The third property is the antiapoptotic activity, characterized by decreased caspase-3 activity and lower expression of pro-apoptotic Bax in the striatum. Conclusion. Based on this comprehensive review, UDCA and TUDCA have the potential to be considered as a therapeutic agent in the management of the Parkinson's disease.

Bile acids: Can the position of hydroxyl substitution influence antidiabetic potency?

Numerous analogous compounds exist in natural products, exhibiting subtle structural variations that nonetheless result in distinct biological activities. Hyodeoxycholic acid (HDCA), ursodeoxycholic acid (UDCA), and deoxycholic acid (DCA) are analogues belonging to the steroids, and related studies have demonstrated that all three possess antidiabetic effects in reducing hyperglycemia. Diabetes mellitus is a metabolic disease with high morbidity and mortality in recent years. A thorough exploration of the mechanisms underlying compounds with potential antidiabetic properties serves as an essential prerequisite for subsequent research endeavors. However, the mechanism of action regarding them has not been fully verified, and the present study identified one of the antidiabetic mechanisms of action of bile acid analogs at the protein and molecular levels. The results suggested that structural differences due to differences in the position of the hydroxyl substituent alter the antidiabetic capacity. The application of machine learning methods for pharmacokinetic prediction contributes to a better understanding of the nature and in vivo behavior of bile acid analogs. This study endeavors to establish a basic reference and experimental foundation to contribute to the ongoing exploration of the potential role of bile acid compounds in antidiabetic mechanisms.

Up-to-Date Snapshot of Current and Emerging Medical Therapies in Primary Biliary Cholangitis

Background/Objectives: Primary biliary cholangitis (PBC) is an autoimmune chronic cholestatic disease of the liver that symptomatically can present with pruritus and fatigue. Its established first- and second-line therapies are ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) although they provide limited symptom management. Liver transplantation offers a potentially curative therapeutic option in refractory cases progressing to cirrhosis. Novel research published after the current guidelines highlights the importance of providing an up-to-date analysis of treatment options available. Methods: In this study, we conducted a literature search using Pubmed, Ovid Medline, and SCOPUS to provide a narrative review of first-line, second-line, and emerging therapies in PBC. Results: UDCA has been well established as a long-term, safe therapy within the literature although it is possible that treatment dosage can be further optimised in refractory patients. It has a favourable side effect profile. Despite improving biochemical markers, histopathological profile, and overall outcomes, up to 30-40% of patients are refractory to it. Age and sex are highlighted as independent indicators of non-responsiveness. This necessitates effective second-line therapies. Future trials could aim to investigate UDCA as a co-first-line therapy. Further supporting results for OCA were found in the interim extension trial of the seminal POISE study. The long-term phase 4 COBOLT trial is still awaiting results to further assess the complications, adherence, and potential adverse effects. It is a viable option in UDCA-refractory patients. The high incidence rate of dose-related pruritis indicates that alternative second-line options are needed. Bezafibrate is an off-label antilipemic agent that shows promise as a prospective second-line therapy option. The landmark BEZURSO trial alleviated some efficacy and safety concerns, but it remains associated with elevated serum creatinine; thus, it should be considered with caution. Other prospective second-line therapies are budesonide, triple therapy, and novel agents such as seladelpar and elafibranor. Conclusions: UDCA should remain the treatment of choice for PBC, though perhaps not as monotherapy. With further investigation, BF shows promise as a new second-line therapy alongside OCA, which it may outperform.

ABC transporters involved in respiratory and cholestatic diseases: From rare to very rare monogenic diseases

ATP-binding cassette (ABC) transporters constitute a 49-member superfamily in humans. These proteins, most of them being transmembrane, allow the active transport of an important variety of substrates across biological membranes, using ATP hydrolysis as an energy source. For an important proportion of these ABC transporters, genetic variations of the loci encoding them have been correlated with rare genetic diseases, including cystic fibrosis and interstitial lung disease (variations in CFTR/ABCC7 and ABCA3) as well as cholestatic liver diseases (variations in ABCB4 and ABCB11). In this review, we first describe these ABC transporters and how their molecular dysfunction may lead to human diseases. Then, we propose a classification of the genetic variants according to their molecular defect (expression, traffic, function and/or stability), which may be considered as a general guideline for all ABC transporters' variants. Finally, we discuss recent progress in the field of targeted pharmacotherapy, which aim to correct specific molecular defects using small molecules. In conclusion, we are opening the path to treatment repurposing for diseases involving similar deficiencies in other ABC transporters.

Biliary complications associated with weight loss, cholelithiasis and choledocholithiasis

Biliary complications like cholelithiasis and choledocholithiasis are more common in bariatric surgery patients due to obesity and rapid weight loss. Patients with a body mass index > 40 face an eightfold risk of developing cholelithiasis. Post-bariatric surgery, especially after laparoscopic Roux-en-Y gastric bypass (LRYGB), 30% of patients develop biliary disease due to rapid weight loss. The aim of this review is to analyze the main biliary complications that occur after bariatric surgery and its management. A review of the literature was conducted mainly from 2010 up to 2023 with regard to biliary complications associated with bariatric patients in SciELO, PubMed, and MEDLINE. Patients undergoing LRYGB have a higher incidence (14.5%) of symptomatic calculi post-surgery compared to those undergoing laparoscopic sleeve gastrectomy at 4.1%. Key biliary complications within 6 to 12 months post-surgery include: Cholelithiasis: 36%; Biliary colic/dyskinesia: 3.86%; Acute cholecystitis: 0.98%-18.1%; Chronic cholecystitis: 70.2%; Choledocholithiasis: 0.2%-5.7% and Pancreatitis: 0.46%-9.4%. Surgeons need to be aware of these complications and consider surgical treatments based on patient symptoms to enhance their quality of life.

Ursodeoxycholic Acid's Effectiveness in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

Aim

This meta-analysis's objective was to assess the effectiveness of ursodeoxycholic acid (UDCA) in the management of nonalcoholic fatty liver disease (NAFLD).

Methods

Electronic databases like PubMed, Embase, Scopus, and Cochrane Library were thoroughly looked for randomized controlled trials determining ursodeoxycholic acid's (UDCAs) effectiveness on the serum liver function tests in NAFLD patients. After screening, seven randomized controlled trials were incorporated overall. Utilizing a fixed effects model, quantitative data synthesis was performed in R version 4.3.1.

Results

The meta-analysis showed significant reductions in alanine transaminase (ALT) (p ≤ 0.0001), aspartate transaminase (p = 0.0009), and gamma-glutamyl transferase (GGT) (p ≤ 0.0001) after UDCA therapy. However, significant reductions in bilirubin (p = 0.6989) and alkaline phosphatase (ALP) (p = 0.1172) levels were not noted. Sensitivity analysis by removing the studies with some concerns of bias was successful in demonstrating a remarkable reduction in heterogeneity for aspartate transaminase and ALP, which was also observed while performing the subgroup analyses via dosage.

Conclusion

Ursodeoxycholic acid was beneficial in patients diagnosed with NAFLD as it significantly reduced aspartate transaminase, ALT and GGT levels. However, more randomized controlled trials are required to be conducted in the future to increase the certainty of the evident findings.

Clinical significance

This meta-analysis strengthens the evidence about the reductions in AST, ALT, and GGT levels observed with ursodeoxycholic acid therapy in NAFLD patients by pooling the data together from the latest RCTs thus proving its hepatoprotective effects which can be beneficial in preventing the associated complications.

How to cite this article

Patel VS, Mahmood SF, Bhatt KH, et al. Ursodeoxycholic Acid's Effectiveness in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis. Euroasian J Hepato-Gastroenterol 2024;14(1):92-98.

Bile Acids as Signaling Molecules: Role of Ursodeoxycholic Acid in Cholestatic Liver Disease

Ursodeoxycholic acid (UDCA) is a natural substance physiologically produced in the liver. Initially used to dissolve gallstones, it is now successfully used in treating primary biliary cirrhosis and as adjuvant therapy for various hepatobiliary cholestatic diseases. However, the mechanisms underlying its beneficial effects still need to be clarified. Evidence suggests three mechanisms of action for UDCA that could benefit humans with cholestatic liver disease (CLD): protection of cholangiocytes against hydrophobic bile acid (BA) cytotoxicity, stimulation of hepatobiliary excretion, and protection of hepatocytes against BA-induced apoptosis. These mechanisms may act individually or together to potentiate them. At the molecular level, it has been observed that UDCA can generate modifications in the transcription and translation of proteins essential in the transport of BA, correcting the deficit in BA secretion in CLD, in addition to activating signaling pathways to translocate these transporters to the sites where they should fulfill their function. Inhibition of BA-induced hepatocyte apoptosis may play a role in CLD, characterized by BA retention in the hepatocyte. Thus, different mechanisms of action contribute to the improvement after UDCA administration in CLD. On the other hand, the effects of UDCA on tissues that possess receptors that may interact with BAs in pathological contexts, such as skeletal muscle, are still unclear. This work aims to describe the main molecular mechanisms by which UDCA acts in the human body, emphasizing the interaction in tissues other than the liver.

Evaluation of therapeutic effect of oral Ursodeoxycholic Acid on indirect hyperbilirubinemia in term neonates undergoing phototherapy: A randomized controlled clinical trial

INTRODUCTION AND AIMS

Phototherapy is the most common treatment modality of neonatal hyperbilirubinemia. We aimed to evaluate the therapeutic effect of oral Ursodeoxycholic Acid (UDCA) on indirect hyperbilirubinemia in term neonates undergoing phototherapy.

MATERIALS AND METHODS

This randomized controlled clinical trial was performed on 106 full-term neonates with jaundice who were admitted to the neonatal ward of 17 Shahrivar Hospital in Rasht, Iran. The neonates were randomly assigned to two groups of intervention (10 mg/kg UDCA+phototherapy) and control (phototherapy alone). Total serum bilirubin (TSB) was measured at the time of admission, during first 12, 24, and 48 hours after admission and at the time of discharge. The duration of hospitalization and side effects were also assessed in both groups. IBM SPSS Statistics for Windows, version 20 was used to analyze the data.

RESULTS

Results showed that in the intervention group, 28 (52.8%) of neonates were boys with the mean age of 5.1±1.25 days. While, in the control group 29 (54.7%) of them were boys with the mean age of 5.19±2.26 days. Bilirubin levels in both groups decreased significantly after hospitalization (at 12, 24 and 48 hours) (P <0.001). The mean of bilirubin at 12, 24 and 48 hours in the intervention and control groups were 17.1, 13.2, 10.2 mg / dl and 17.1, 14.2 and 11.3 mg / dl, respectively. At the time of discharge, TSB in the former compared to the latter group was significantly reduced (7.74± 1.39 vs. 8.67±1.35) (P = 0.001). In addition, the duration of hospitalization was considerably shorter in the intervention compared to the control group (P = 0.038) and no side effects were observed.

CONCLUSIONS

Administering UDCA plus phototherapy reduced TSB and length of hospital stay with proper safety and efficacy. Therefore, it seems that this combination can be an appropriate treatment modality in neonatal hyperbilirubinemia.

Causal relationship between blood metabolites and risk of five infections: a Mendelian randomization study

OBJECTIVE

Infectious diseases continue to pose a significant threat in the field of global public health, and our understanding of their metabolic pathogenesis remains limited. However, the advent of genome-wide association studies (GWAS) offers an unprecedented opportunity to unravel the relationship between metabolites and infections.

METHODS

Univariable and multivariable Mendelian randomization (MR) was commandeered to elucidate the causal relationship between blood metabolism and five high-frequency infection phenotypes: sepsis, pneumonia, upper respiratory tract infections (URTI), urinary tract infections (UTI), and skin and subcutaneous tissue infection (SSTI). GWAS data for infections were derived from UK Biobank and the FinnGen consortium. The primary analysis was conducted using the inverse variance weighted method on the UK Biobank data, along with a series of sensitivity analyses. Subsequently, replication and meta-analysis were performed on the FinnGen consortium data.

RESULTS

After primary analysis and a series of sensitivity analyses, 17 metabolites were identified from UK Biobank that have a causal relationship with five infections. Upon joint analysis with the FinGen cohort, 7 of these metabolites demonstrated consistent associations. Subsequently, we conducted a multivariable Mendelian randomization analysis to confirm the independent effects of these metabolites. Among known metabolites, genetically predicted 1-stearoylglycerol (1-SG) (odds ratio [OR] = 0.561, 95% confidence interval [CI]: 0.403-0.780, P < 0.001) and 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (CMPF) (OR = 0.780, 95%CI: 0.689-0.883, P < 0.001) was causatively associated with a lower risk of sepsis, and genetically predicted phenylacetate (PA) (OR = 1.426, 95%CI: 1.152-1.765, P = 0.001) and cysteine (OR = 1.522, 95%CI: 1.170-1.980, P = 0.002) were associated with an increased risk of UTI. Ursodeoxycholate (UDCA) (OR = 0.906, 95%CI: 0.829-0.990, P = 0.029) is a protective factor against pneumonia. Two unknown metabolites, X-12407 (OR = 1.294, 95%CI: 1.131-1.481, P < 0.001), and X-12847 (OR = 1.344, 95%CI: 1.152-1.568, P < 0.001), were also identified as independent risk factors for sepsis.

CONCLUSIONS

In this MR study, we demonstrated a causal relationship between blood metabolites and the risk of developing sepsis, pneumonia, and UTI. However, there was no evidence of a causal connection between blood metabolites and the risk of URTI or SSTI, indicating a need for larger-scale studies to further investigate susceptibility to certain infection phenotypes.

Metabolic dysfunction-associated gallstone disease: expecting more from critical care manifestations

About 20% of adults worldwide have gallstones which are solid conglomerates in the biliary tree made of cholesterol monohydrate crystals, mucin, calcium bilirubinate, and protein aggregates. About 20% of gallstone patients will definitively develop gallstone disease, a condition which consists of gallstone-related symptoms and/or complications requiring medical therapy, endoscopic procedures, and/or cholecystectomy. Gallstones represent one of the most prevalent digestive disorders in Western countries and patients with gallstone disease are one of the largest categories admitted to European hospitals. About 80% of gallstones in Western countries are made of cholesterol due to disturbed cholesterol homeostasis which involves the liver, the gallbladder and the intestine on a genetic background. The incidence of cholesterol gallstones is dramatically increasing in parallel with the global epidemic of insulin resistance, type 2 diabetes, expansion of visceral adiposity, obesity, and metabolic syndrome. In this context, gallstones can be largely considered a metabolic dysfunction-associated gallstone disease, a condition prone to specific and systemic preventive measures. In this review we discuss the key pathogenic and clinical aspects of gallstones, as the main clinical consequences of metabolic dysfunction-associated disease.

Emerging Therapeutic Strategies in The Fight Against Primary Biliary Cholangitis

The liver has a vital role in many metabolic and regulatory processes in the body. Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is a chronic cholestatic autoimmune disease of the intrahepatic bile ducts associated with loss of tolerance to mitochondrial antigens. At this time there is no definitive cure for PBC; however, ursodeoxycholic acid (UDCA) has been shown to reduce injury when administered as the first line of treatment. Additional therapeutics can be given concurrently or as an alternative to UDCA to manage the symptoms and further curb disease progression. Currently, a liver transplant is the only potentially curative option when the patient has developed end-stage liver disease or intractable pruritus. This review aims to delineate the pathogenesis of primary biliary cholangitis and shed light on current therapeutic strategies in the treatment of PBC.

Ursodeoxycholic Acid Does Not Improve COVID-19 Outcome in Hospitalized Patients

Ursodeoxycholic acid (UDCA) was demonstrated to reduce susceptibility to SARS-CoV-2 infection in vitro and improve infection course in chronic liver diseases. However, real-life evidence is lacking. We analyzed the impact of UDCA on COVID-19 outcomes in patients hospitalized in a tertiary center. Between January 2020 and January 2023, among 3847 patients consecutively hospitalized for COVID19, 57 (=UDCA group) were taking UDCA. The UDCA and the control groups (n = 3790) did not differ concerning comorbidities including diabetes mellitus type 2 (15.8% vs. 12.8%) and neoplasia (12.3% vs. 9.4%). Liver diseases and vaccination rate were more common in the UDCA group (14.0% vs. 2.5% and 54.4% vs. 30.2%, respectively). Overall mortality and CPAP treatment were 22.8 % and 15.7% in the UDCA, and 21.3% and 25.9% in the control group. Mortality was similar (p = 0.243), whereas UDCA was associated with a lower rate of CPAP treatment (OR = 0.76, p < 0.05). Treatment with UDCA was not an independent predictor of survival in patients hospitalized for COVID-19.

Primary Biliary Cholangitis: Promising Emerging Innovative Therapies and Their Impact on GLOBE Scores

Primary biliary cholangitis (PBC), previously referred to as primary biliary cirrhosis, is an autoimmune disorder leading to the destruction of intra-hepatic bile ducts. If untreated, progressive bile duct damage and cholestasis can lead to ductopenia and result in cirrhosis. Ursodiol, the first drug approved for PBC, has changed the natural history of this disease and improved patient outcomes. Subsequently, several new prediction models incorporating a response to ursodiol were developed. These include the GLOBE score, which was shown to predict long-term outcomes in patients with PBC. In 2016, obeticholic acid (OCA) became the second drug to be approved by the FDA, predominantly based on improvement in alkaline phosphatase (ALP) levels. This trial has subsequently influenced the design of clinical trials. Several drugs are currently being evaluated as therapeutic options for PBC, with improvement in ALP being a main endpoint. In this review, we will discuss the impact of new therapies on GLOBE scores in patients with PBC.

Primary biliary cholangitis: Epidemiology, prognosis, and treatment

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune liver disease characterized by a destructive, small duct, and lymphocytic cholangitis, and marked by the presence of antimitochondrial antibodies. The incidence and prevalence of PBC vary widely in different regions and time periods, and although disproportionally more common among White non-Hispanic females, contemporary data show a higher prevalence in males and racial minorities than previously described. Outcomes largely depend on early recognition of the disease and prompt institution of treatment, which, in turn, are directly influenced by provider bias and socioeconomic factors. Ursodeoxycholic acid remains the initial treatment of choice for PBC, with obeticholic acid and fibrates (off-label therapy) reserved as add-on therapy for the management of inadequate responders or those with ursodeoxycholic acid intolerance. Novel and repurposed drugs are currently at different stages of clinical development not only for the treatment of PBC but also for its symptomatic management. Here, we summarize the most up-to-date data regarding the epidemiology, prognosis, and treatment of PBC, providing clinically useful information for its holistic management.

Effects of Biliary Phospholipids on Cholesterol Crystallization and Growth in Gallstone Formation

The prevalence of cholesterol gallstone disease is increasing, primarily due to the global epidemic of obesity associated with insulin resistance, and this trend leads to a considerable healthcare, financial, and social burden worldwide. Although phospholipids play an essential role in maintaining cholesterol solubility in bile through both mixed micelles and vesicles, little attention has been paid to the impact of biliary phospholipids on the pathogenesis of cholesterol gallstone formation. A reduction or deficiency of biliary phospholipids results in a distinctly abnormal metastable physical-chemical state of bile predisposing to supersaturation with cholesterol. Changes in biliary phospholipid concentrations influence cholesterol crystallization by yielding both liquid crystalline and "anhydrous" crystalline metastable intermediates, evolving into classical parallelogram-shaped cholesterol monohydrate crystals in supersaturated bile. As a result, five distinct crystallization pathways, A-E, have been defined, mainly based on the prime habits of liquid and solid crystals in the physiological or pathophysiological cholesterol saturation of gallbladder and hepatic bile. This review concisely summarizes the chemical structures and physical-chemical properties of biliary phospholipids and their physiological functions in bile formation and cholesterol solubility in bile, as well as comprehensively discusses the latest advances in the role of biliary phospholipids in cholesterol crystallization and growth in gallstone formation, largely based on the findings from clinical and animal studies and in vitro experiments. The insights gleaned from uncovering the cholelithogenic mechanisms are expected to form a fundamental framework for investigating the hitherto elusive events in the earliest stage of cholesterol nucleation and crystallization. This may help to identify better measures for early diagnosis and prevention in susceptible subjects and effective treatment of patients with gallstones.

Selected Aspects of the Intricate Background of Immune-Related Cholangiopathies-A Critical Overview

Primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are rare immune-related cholangiopathies with still poorly explained pathogenesis. Although triggers of chronic inflammation with subsequent fibrosis that affect cholangiocytes leading to obliteration of bile ducts and conversion to liver cirrhosis are unclear, both disorders are regarded to be multifactorial. Different factors can contribute to the development of hepatocellular injury in the course of progressive cholestasis, including (1) body accumulation of bile acids and their toxicity, (2) decreased food intake and nutrient absorption, (3) gut microbiota transformation, and (4) reorganized host metabolism. Growing evidence suggests that intestinal microbiome composition not only can be altered by liver dysfunction, but in turn, it actively impacts hepatic conditions. In this review, we highlight the role of key factors such as the gut-liver axis, intestinal barrier integrity, bile acid synthesis and circulation, and microbiome composition, which seem to be strongly related to PBC and PSC outcome. Emerging treatments and future therapeutic strategies are also presented.

Secondary bile acids and the biliary epithelia: The good and the bad

The biliary tract has been considered for several decades a passive system just leading the hepatic bile to the intestine. Nowadays several researches demonstrated an important role of biliary epithelia (i.e. cholangiocytes) in bile formation. The study of biliary processes therefore maintains a continuous interest since the possible important implications regarding chronic cholestatic human diseases, such as primary biliary cholangitis or primary sclerosing cholangitis. Bile acids (BAs), produced by the liver, are the most represented organic molecules in bile. The physiologic importance of BAs was initially attributed to their behavior as natural detergents but several studies now demonstrate they are also important signaling molecules. In this minireview the effect of BAs on the biliary epithelia are reported focusing in particular on secondary (deriving by bacterial manipulation of primary molecules) ones. This class of BAs is demonstrated to have relevant biological effects, ranging from toxic to therapeutic ones. In this family ursodeoxycholic and lithocholic acid present the most interesting features. The molecular mechanisms linking ursodeoxycholic acid to its beneficial effects on the biliary tract are discussed in details as well as data on the processes leading to lithocholic damage. These findings suggest that expansion of research in the field of BAs/cholangiocytes interaction may increase our understanding of cholestatic diseases and should be helpful in designing more effective therapies for biliary disorders.

A Randomized, Dose-Finding, Proof-of-Concept Study of Berberine Ursodeoxycholate in Patients With Primary Sclerosing Cholangitis

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a fibroinflammatory disease of the bile ducts leading to cirrhosis and hepatic decompensation. There are no approved pharmaceutical therapies for PSC. Berberine ursodeoxycholate (HTD1801) is an ionic salt of berberine and ursodeoxycholic acid with pleiotropic mechanisms of action.

METHODS

An 18-week proof-of-concept study was conducted to assess the safety and efficacy of HTD1801 in PSC. This study had three 6-week periods: (i) a placebo-controlled period, (ii) a treatment extension period, and (iii) a randomized treatment withdrawal period. The primary end point was change from baseline in alkaline phosphatase (ALP) at week 6.

RESULTS

Fifty-five patients were randomized and treated; 35 (64%) had inflammatory bowel disease and 22 (40%) had previously received ursodeoxycholic acid. Patients were initially randomized to placebo (n = 16), HTD1801 500 mg BID (n = 15), or HTD1801 1000 mg BID (n = 24). At baseline, mean (range) ALP values were 414 U/L (138-1,048), 397 U/L (237-773), and 335 U/L (122-882) for the placebo, HTD1801 500 mg BID, and HTD1801 1,000 mg BID groups, respectively. At week 6, a significant decrease in ALP was observed with HTD1801 (least square mean; HTD1801 500 mg BID = -53 U/L, P = 0.016; HTD1801 1000 mg BID = -37 U/L, P = 0.019) compared with placebo (98 U/L). ALP reductions were sustained through week 18 in those who remained on therapy, whereas ALP increased in those who crossed over to placebo during period 3. HTD1801 was generally well tolerated; 4 patients experienced serious adverse events, none attributed to HTD1801.

DISCUSSION

HTD1801 is associated with significant improvement in ALP and warrants further study as a treatment for PSC.

Primary Biliary Cholangitis and Primary Sclerosing Cholangitis: Current Knowledge of Pathogenesis and Therapeutics

Cholangiopathies encompass various biliary diseases affecting the biliary epithelium, resulting in cholestasis, inflammation, fibrosis, and ultimately liver cirrhosis. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the most important progressive cholangiopathies in adults. Much research has broadened the scope of disease biology to genetic risk, epigenetic changes, dysregulated mucosal immunity, altered biliary epithelial cell function, and dysbiosis, all of which interact and arise in the context of ill-defined environmental triggers. An in-depth understanding of the molecular pathogenesis of these cholestatic diseases will help clinicians better prevent and treat diseases. In this review, we focus on the main underlying mechanisms of disease initiation and progression, and novel targeted therapeutics beyond currently approved treatments.

Integrative analysis of multi-omics data to detect the underlying molecular mechanisms for obesity in vivo in humans

BACKGROUND

Obesity is a complex, multifactorial condition in which genetic play an important role. Most of the systematic studies currently focuses on individual omics aspect and provide insightful yet limited knowledge about the comprehensive and complex crosstalk between various omics levels.

SUBJECTS AND METHODS

Therefore, we performed a most comprehensive trans-omics study with various omics data from 104 subjects, to identify interactions/networks and particularly causal regulatory relationships within and especially those between omic molecules with the purpose to discover molecular genetic mechanisms underlying obesity etiology in vivo in humans.

RESULTS

By applying differentially analysis, we identified 8 differentially expressed hub genes (DEHGs), 14 differentially methylated regions (DMRs) and 12 differentially accumulated metabolites (DAMs) for obesity individually. By integrating those multi-omics biomarkers using Mendelian Randomization (MR) and network MR analyses, we identified 18 causal pathways with mediation effect. For the 20 biomarkers involved in those 18 pairs, 17 biomarkers were implicated in the pathophysiology of obesity or related diseases.

CONCLUSIONS

The integration of trans-omics and MR analyses may provide us a holistic understanding of the underlying functional mechanisms, molecular regulatory information flow and the interactive molecular systems among different omic molecules for obesity risk and other complex diseases/traits.

Ursodeoxycholic Acid and SMOFlipid for Treating Parenteral Nutrition Associated Cholestasis in Infants

Background: Parenteral nutrition-associated cholestasis (PNAC) is frequently seen in preterm infants receiving total parenteral nutrition (TPN) for a long duration. The pathogenesis of PNAC is believed to be multifactorial; however, phytosterols are hepatotoxic, resulting in cholestasis. A novel lipid emulsion consisting of a mixture of soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOFlipid) with a low level of phytosterols has been shown to improve cholestasis. Moreover, ursodeoxycholic acid (UDCA) has improved bile flow and normalized liver function tests. This study aimed to determine the effect of UDCA and SMOFlipid in preventing and treating PNAC in infants.

Methods: We conducted a retrospective cohort study that included all infants who received TPN for at least five days between January 2010 and December 2018, who also received UDCA for the treatment of cholestasis, and infants who developed cholestasis but were not treated with UDCA. In addition, any infants who received SMOFlipid for parenteral nutrition during the same period were included. We recorded multiple variables, including neonatal demographic data, major medical diagnosis, liver function, medications, and maternal variables.

Results: A total of 58 infants with cholestasis who received UDCA for treatment were identified. The infants were divided into two groups, Group 1 infants had gestational age (GA) of ≤32 weeks, and Group 2 had GA of >32 weeks. We found that combining SMOFlipid with UDCA resulted in a significant reduction in cholestasis duration in both groups. Infants in Group 1 who received SMOFlipid had cholestasis for a mean of 67 ± 57 days, and those who did not receive SMOFlipid had cholestasis for a mean of 145 ± 102 days (p=0.04). Infants in Group 2 who received SMOFlipid had cholestasis for a mean of 38.2 ± 28 days, and those who did not receive SMOFlipid had cholestasis for a mean of 117 ± 119 days (p=0.02).

Conclusions: According to our results, the use of UDCA and SMOFlipid reduced the duration of parenteral nutrition-associated with cholestasis in very low birth weight infants.

Management of biliary stones in bariatric surgery

Morbidly obese and post-bariatric surgery patients are at increased risk for biliary stones formation. The complications related to biliary stones may impose complexity on their management. This study aimed to review the management of biliary conditions in obese and bariatric patients. In this study, a narrative review was performed of the medical, surgical, and endoscopic procedures for the management of biliary stones and their related complications. Knowing the main prophylactic and therapeutic interventions options is essential for clinicians to properly manage the biliary stones in patients candidates or submitted to bariatric surgery.

A phase 2, proof of concept, randomised controlled trial of berberine ursodeoxycholate in patients with presumed non-alcoholic steatohepatitis and type 2 diabetes

Non-alcoholic steatohepatitis is frequently associated with diabetes and may cause progressive liver disease. Current treatment options are limited. Here we report on a prospective, randomised, double-blind, placebo-controlled trial of two doses of HTD1801 (berberine ursodeoxycholate, an ionic salt of berberine and ursodeoxycholic acid), versus placebo that was conducted in 100 subjects with fatty liver disease and diabetes (NCT03656744). Treatment was for 18 weeks with a primary endpoint of reduction in liver fat content measured by magnetic resonance imaging proton density fat fraction. Key secondary endpoints included improvement in glycemic control, liver-associated enzymes and safety. The pre-specified primary endpoint was met. Thus, subjects receiving 1000 mg twice a day of berberine ursodeoxycholate had significantly greater reduction in liver fat content than in placebo recipients (mean absolute decrease -4.8% vs. -2.0% (p = 0.011). Compared to placebo, subjects receiving this dose also experienced significant improvement in glycemic control as well as reductions in liver-associated enzymes and significant weight loss. Diarrhea and abdominal discomfort were the most frequently reported adverse events. We conclude that berberine ursodeoxycholate has a broad spectrum of metabolic activity in patients with presumed NASH and diabetes. It is relatively well tolerated and merits further development as a treatment for NASH with diabetes.

Drug-Induced Vanishing Bile Duct Syndrome: From Pathogenesis to Diagnosis and Therapeutics

The most concerned issue in the context of drug/herb-induced chronic cholestasis is vanishing bile duct syndrome. The progressive destruction of intrahepatic bile ducts leading to ductopenia is usually not dose dependent, and has a delayed onset that should be suspected when abnormal serum cholestasis enzyme levels persist despite drug withdrawal. Immune-mediated cholangiocyte injury, direct cholangiocyte damage by drugs or their metabolites once in bile, and sustained exposure to toxic bile salts when biliary epithelium protective defenses are impaired are the main mechanisms of cholangiolar damage. Current therapeutic alternatives are scarce and have not shown consistent beneficial effects so far. This review will summarize the current literature on the main diagnostic tools of ductopenia and its histological features, and the differential diagnostic with other ductopenic diseases. In addition, pathomechanisms will be addressed, as well as the connection between them and the supportive and curative strategies for ductopenia management.

The protective role of hydrophilic tetrahydroxylated bile acids (THBA)

Bile acids are key components of bile required for human health. In humans and mice, conditions of reduced bile flow, cholestasis, induce bile acid detoxification by producing tetrahydroxylated bile acids (THBA), more hydrophilic and less cytotoxic than the usual bile acids, which are typically di- or tri-hydroxylated. Mice deficient in the Bile Salt Export Pump (Bsep, or Abcb11), the primary bile acid transporter in liver cells, produce high levels of THBA, and avoid the severe liver damage typically seen in humans with BSEP deficiencies. THBA can suppress bile acid-induced liver damage in Mdr2-deficient mice, caused by their lack of phospholipids in bile exposing their biliary tracts to unbound bile acids. Here we review THBA-related works in both animals and humans, and discuss their potential relevance and applications as a class of functional bile acids.

Effect of Ursodeoxycholic Acid on the Biodistribution and Excretion of Technetium-99m Radiopharmaceuticals in Rat: A Potential Image Quality Enhancer

PURPOSE

This study aimed to investigate the effect of ursodeoxycholic acid (UDCA) on the biodistribution and excretion of technetium-99m (Tc-99m)-labeled radiopharmaceuticals.

MATERIALS AND METHODS

Tc-99m hydroxy-methylene-diphosphonate (HDP), Tc-99m pertechnetate, and Tc-99m dimercaptosuccinic acid (DMSA) were injected via the tail vein of rats. After 30 min, the control group was administered saline, and the UDCA group was given UDCA orally. Scintigraphy images were acquired after 30 min and 1, 2, 3, and 4 h. Radioactivity and rate of change were compared. Tc-99m mercaptoacetyltriglycine (MAG₃) imaging was also performed.

RESULTS

In image analysis of Tc-99m HDP, radioactivity of the buttock was lower in the UDCA group at 4 h. Rates of change in the buttock were significantly different at 3 h-30 min and 4 h-30 min, and buttock radioactivity in the UDCA group had decreased more. In analysis of Tc-99m pertechnetate, radioactivity of the buttock was higher in the control group. Rates of change in the thyroid gland and buttock were different at 1 h-30 min, 3 h-30 min, and 4 h-30 min, with radioactivity in the UDCA group decreasing more. In the analysis of Tc-99m DMSA, while the radioactivity of the kidneys in the control group showed little decrease at 1 h-30 min, that in the UDCA group increased. In the analysis of Tc-99m MAG₃ images, radioactivity and radioactivity/total body radioactivity (TBA) values for the kidneys were higher in the UDCA group at 2 min. At 5 and 10 min, radioactivity/TBA values for soft tissue in the UDCA group were lower than those in the control group.

CONCLUSION

This study demonstrated that administration of UDCA increases renal excretion and soft tissue clearance of radiopharmaceuticals. This investigation could contribute to the broadening of applications of UDCA.

Monomeric bile acids modulate the ATPase activity of detergent-solubilized ABCB4/MDR3

ABCB4, also called multidrug-resistant protein 3 (MDR3), is an ATP binding cassette transporter located in the canalicular membrane of hepatocytes that specifically translocates phosphatidylcholine (PC) lipids from the cytoplasmic to the extracellular leaflet. Due to the harsh detergent effect of bile acids, PC lipids provided by ABCB4 are extracted into the bile. While it is well known that bile acids are the major extractor of PC lipids from the membrane into bile, it is unknown whether only PC lipid extraction is improved or whether bile acids also have a direct effect on ABCB4. Using in vitro experiments, we investigated the modulation of ATP hydrolysis of ABC by different bile acids commonly present in humans. We demonstrated that all tested bile acids stimulated ATPase activity except for taurolithocholic acid, which inhibited ATPase activity due to its hydrophobic nature. Additionally, we observed a nearly linear correlation between the critical micelle concentration and maximal stimulation by each bile acid, and that this modulation was maintained in the presence of PC lipids. This study revealed a large effect of 24-nor-ursodeoxycholic acid, suggesting a distinct mode of regulation of ATPase activity compared with other bile acids. In addition, it sheds light on the molecular cross talk of canalicular ABC transporters of the human liver.

[Biliary sludge: pathogenesis, etiology and drug therapy]

AIM

To evaluate the effectiveness of the use of ursodeoxycholic acid (UDCA) for the treatment of biliary sludge (BS) and to compare the therapeutic effectiveness of the German substance UDCA and generic drugs from other manufacturers.

MATERIALS AND METHODS

The study involved 65 patients diagnosed with BS (K80.8). To assess the severity of BS, ultrasound of the gallbladder was performed before treatment, after 1, 3, 6 months during therapy, as well as an assessment of its contractility. All patients were randomized into 2 groups. Patients of the main group received UDCA Ursofalk (Germany) at a dose of 10 mg/kg for at least 6 months. Patients in the comparison group received UDCA (another manufacturer) at a dose of 10 mg/kg for at least 6 months.

RESULTS

After 3 months of follow-up, the number of patients with dissolved sludge in the main group was 87.1%, while in the comparison group 50%. In 71% of patients, the normalization of the lean volume of the gallbladder was noted, and in the comparison group only in 47.1%. After 6 months of follow-up, complete resolution of BS in the main group was observed in 93.5% of cases, and in the comparison group in 73.6% of cases.

CONCLUSION

As a result of the study, the high effectiveness of Ursofalk during oral litolysis in patients with stage I GI (BS) in the first 3 months of therapy, as well as the normalization of the contractile function of the gallbladder, were noted.

Synthetic Conjugates of Ursodeoxycholic Acid Inhibit Cystogenesis in Experimental Models of Polycystic Liver Disease

BACKGROUND AND AIMS

Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of symptomatic biliary cysts. Current surgical and pharmacological approaches are ineffective, and liver transplantation represents the only curative option. Ursodeoxycholic acid (UDCA) and histone deacetylase 6 inhibitors (HDAC6is) have arisen as promising therapeutic strategies, but with partial benefits.

APPROACH AND RESULTS

Here, we tested an approach based on the design, synthesis, and validation of a family of UDCA synthetic conjugates with selective HDAC6i capacity (UDCA-HDAC6i). Four UDCA-HDAC6i conjugates presented selective HDAC6i activity, UDCA-HDAC6i #1 being the most promising candidate. UDCA orientation within the UDCA-HDAC6i structure was determinant for HDAC6i activity and selectivity. Treatment of polycystic rats with UDCA-HDAC6i #1 reduced their hepatomegaly and cystogenesis, increased UDCA concentration, and inhibited HDAC6 activity in liver. In cystic cholangiocytes UDCA-HDAC6i #1 restored primary cilium length and exhibited potent antiproliferative activity. UDCA-HDAC6i #1 was actively transported into cells through BA and organic cation transporters.

CONCLUSIONS

These UDCA-HDAC6i conjugates open a therapeutic avenue for PLDs.

Bile acid-based dual-functional prodrug nanoparticles for bone regeneration through hydrogen peroxide scavenging and osteogenic differentiation of mesenchymal stem cells

A high level of reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂) upregulates pro-inflammatory cytokines and inhibits the osteogenic differentiation of mesenchymal stem cells (MSCs), which are key factors in bone regeneration. Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, has antioxidant and anti-inflammatory activities and also plays beneficial roles in bone regeneration by stimulating the osteogenic differentiation of MSCs while suppressing their adipogenic differentiation. Despite its remarkable capacity for bone regeneration, multiple injections of UDCA induce adverse side effects such as mechanical stress and contamination in bone defects. To fully exploit the beneficial roles of UDCA, a concept polymeric prodrug was developed based on the hypothesis that removal of overproduced H₂O₂ will potentiate the osteogenic functions of UDCA. In this work, we report bone regenerative nanoparticles (NPs) formulated from a polymeric prodrug of UDCA (PUDCA) with UDCA incorporated in its backbone through H₂O₂-responsive peroxalate linkages. The PUDCA NPs displayed potent antioxidant and anti-inflammatory activities in MSCs and induced osteogenic rather than adipogenic differentiation of the MSCs. In rat models of bone defect, the PUDCA NPs exhibited significantly better bone regeneration capacity and anti-inflammatory effects than equivalent amounts of UDCA. We anticipate that PUDCA NPs have tremendous translational potential as bone regenerative agents.

Pharmacokinetics and pharmacodynamics of HTD1801 (berberine ursodeoxycholate, BUDCA) in patients with hyperlipidemia

Background

Reduction in elevated serum cholesterol concentrations is important in the management of individuals at risk of atherosclerotic cardiovascular disease (ASCVD), such as myocardial infarction and thrombotic stroke. Although HMGCoA reductase inhibitors (“statins”) are frequently used for this purpose, a significant proportion of patients remain at increased residual risk of ASCVD as they do not adequately address some of the associated co-morbidities such as diabetes and fatty liver disease.

Methods

A double-blind, randomized, placebo-controlled, dose ranging study was carried out that compared three doses of berberine ursodeoxycholate (BUDCA) to placebo in a cohort of subjects with a history of hypercholesterolemia and serum LDL cholesterol levels above 2.59 mmol/L (> 99.9 mg/dL). BUDCA was administered in two divided doses each day for 28 days. The primary endpoints of the study were safety and tolerability of this new compound, as well as its effect in lowering serum lipid and lipoprotein concentrations.

Results

A total of 50 subjects were enrolled into three dose cohorts in this study. BUDCA was generally well tolerated, even at doses of 2000 mg per day (the highest dose group); there were no significant adverse effects reported and this highest dose was associated with significant reductions in LDL cholesterol. By day 28 and with the highest dose of BUDCA, there were significant reductions in the serum concentrations of total cholesterol by 8.2% (P = 0.0004) and LDL cholesterol by 10.4% (P = 0.0006), but no significant changes in triglyceride and HDL cholesterol concentrations.

Conclusions

BUDCA is a new single molecular entity that has a significant but modest effect in safely lowering serum LDL-cholesterol concentrations in individuals with a history of hypercholesterolemia. It has a potential use for treating hypercholesterolemia in individuals who cannot take statins, and possibly as adjunctive to other agents, such as ezetimibe or bempedoic acid.

Trial registration

The study was registered on Clinicaltrials.gov (NCT03381287).

Nutrition and Gastrointestinal Microbiota, Microbial-Derived Secondary Bile Acids, and Cardiovascular Disease

PURPOSE OF REVIEW

The goal is to review the connection between gut microbiota and cardiovascular disease, with specific emphasis on bile acids, and the influence of diet in modulating this relationship.

RECENT FINDINGS

Bile acids exert a much broader range of biological functions than initially recognized, including regulation of cardiovascular function through direct and indirect mechanisms. There is a bi-directional relationship between gut microbiota modulation of bile acid-signaling properties, and their effects on gut microbiota composition. Evidence, primarily from rodent models and limited human trials, suggest that dietary modulation of the gut microbiome significantly impacts bile acid metabolism and subsequently host physiological response(s). Available evidence suggests that the link between diet, gut microbiota, and CVD risk is potentially mediated via bile acid effects on diverse metabolic pathways. However, further studies are needed to confirm/expand and translate these findings in a clinical setting.

Tauroursodeoxycholate protects from glycochenodeoxycholate-induced gene expression changes in perfused rat liver

Tauroursodeoxycholate (TUDC) is well known to protect against glycochenodeoxycholate (GCDC)-induced apoptosis in rat hepatocytes. In the present study, we analyzed whether TUDC also exerts protective effects by modulating GCDC-induced gene expression changes. For this, gene array-based transcriptome analysis and quantitative polymerase chain reaction (qPCR) were performed on RNA isolated from rat livers perfused with GCDC, TUDC or a combination of both (each 20 μm for 2 h). GCDC led to a significant increase of lactate dehydrogenase (LDH) into the effluent perfusate, which was prevented by TUDC. GCDC, TUDC and co-perfusion induced distinct gene expression changes. While GCDC upregulated the expression of several pro-inflammatory genes, co-perfusion with TUDC increased the expression of pro-proliferative and anti-apoptotic p53 target genes. In line with this, levels of serine20-phosphorylated p53 and of its target gene p21 were elevated by GCDC in a TUDC-sensitive way. GCDC upregulated the oxidative stress surrogate marker 8OH(d)G and the pro-apoptotic microRNAs miR-15b/16 and these effects were prevented by TUDC. The upregulation of miR-15b and miR-16 in GCDC-perfused livers was accompanied by a downregulation of several potential miR-15b and miR-16 target genes. The present study identified changes in the transcriptome of the rat liver which suggest, that TUDC is hepatoprotective by counteracting GCDC-induced gene expression changes.

Protective Effects of Ursodeoxycholic Acid on Valproic Acid Induced Hepatotoxicity in Epileptic Children with Recurrent Seizure; A Double-Blinded Randomized Clinical Trial

Background : There are controversies regarding the protective role of ursodeoxycholic acid (UDCA) against valproic acid (VPA)-induced hepatotoxicity in children. In the present clinical trial, we assessed the potential role of UDCA in preventing VPA-induced fluctuations of hepatic enzymes in epileptic children with recurrent seizures. Methods: Two-hundred children with epileptic seizures were randomly allocated into either intervention (VPA+UDCA) or control (VPA+ placebo) group. Fluctuations of liver enzymes were recorded at baseline, as well as 48 hours, 1 month, and 3 months following the interventions. Results: The mean age of the patients was 7.33±2.96 years (the range of 4-16). Males and females constituted 43 (43%) and 57 (57%) subjects in each group respectively. There were no significant differences in the baseline levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) between the intervention and control groups. At 48 hours post-intervention, AST and ALT increased 1.7% and 11.05% (23.18±7.91 and 30.75±4.20 IU/l) in the intervention group and 21.3% and 35% (28.46±3.71 and 35.62±7.72 IU/l) in the control group respectively (P<0.0001). Both AST (P<0.001) and ALT (P=0.03) levels were significantly lower in the intervention than placebo group at 1-month post-intervention. At 3-month post-intervention; however, while AST level still was significantly higher in the control (29.87±5.41 IU/l) than intervention (21.63±6.87 IU/l, P<0.0001), ALT level was not significantly different between the two groups (32.72±5.59 IU/l and 32.01±7.89 IU/l respectively, P=0.5). Conclusion: UDCA can be an effective drug to manage VPA-induced fluctuations of hepatic enzymes in children with recurrent epileptic seizures.

Nasal administration of nanoencapsulated geraniol/ursodeoxycholic acid conjugate: Towards a new approach for the management of Parkinson's disease

The combined use of different therapeutic agents in the treatment of neurodegenerative disorders is a promising strategy to halt the disease progression. In this context, we aimed to combine the anti-inflammatory properties of geraniol (GER) with the mitochondrial rescue effects of ursodeoxycholic acid (UDCA) in a newly-synthesized prodrug, GER-UDCA, a potential candidate against Parkinson's disease (PD). GER-UDCA was successfully synthetized and characterized in vitro for its ability to release the active compounds in physiological environments. Because of its very poor solubility, GER-UDCA was entrapped into both lipid (SLNs) and polymeric (NPs) nanoparticles in order to explore nose-to-brain pathway towards brain targeting. Both GER-UDCA nanocarriers displayed size below 200 nm, negative zeta potential and the ability to increase the aqueous dissolution rate of the prodrug. As SLNs exhibited the higher GER-UDCA dissolution rate, this formulation was selected for the in vivo GER-UDCA brain targeting experiments. The nasal administration of GER-UDCA-SLNs (1 mg/kg of GER-UDCA) allowed to detect the prodrug in rat cerebrospinal fluid (concentration range = 1.1 to 4.65 μg/mL, 30-150 min after the administration), but not in the bloodstream, thus suggesting the direct nose to brain delivery of the prodrug. Finally, histopathological evaluation demonstrated that, in contrast to the pure GER, nasal administration of GER-UDCA-SLNs did not damage the structural integrity of the nasal mucosa. In conclusion, the present data suggest that GER-UDCA-SLNs could provide an effective and non-invasive approach to boost the access of GER and UDCA to the brain with low dosages.

Primary biliary cholangitis: pathogenesis and therapeutic opportunities

Primary biliary cholangitis is a chronic, seropositive and female-predominant inflammatory and cholestatic liver disease, which has a variable rate of progression towards biliary cirrhosis. Substantial progress has been made in patient risk stratification with the goal of personalized care, including early adoption of next-generation therapy with licensed use of obeticholic acid or off-label fibrate derivatives for those with insufficient benefit from ursodeoxycholic acid, the current first-line drug. The disease biology spans genetic risk, epigenetic changes, dysregulated mucosal immunity and altered biliary epithelial cell function, all of which interact and arise in the context of ill-defined environmental triggers. A current focus of research on nuclear receptor pathway modulation that specifically and potently improves biliary excretion, reduces inflammation and attenuates fibrosis is redefining therapy. Patients are benefiting from pharmacological agonists of farnesoid X receptor and peroxisome proliferator-activated receptors. Immunotherapy remains a challenge, with a lack of target definition, pleiotropic immune pathways and an interplay between hepatic immune responses and cholestasis, wherein bile acid-induced inflammation and fibrosis are dominant clinically. The management of patient symptoms, particularly pruritus, is a notable goal reflected in the development of rational therapy with apical sodium-dependent bile acid transporter inhibitors.

Protective Effects of Nutria Bile against Thioacetamide-Induced Liver Injury in Mice

Several eradication programs have been developed and executed to curb alien invasive species that tend to damage the ecological environments they colonize; however, only few studies have evaluated the utilization of carcasses of these species after eradication. Nutria (Myocastor coypus) is an invasive rodent species targeted by eradication programs in many countries. We noted that nutria produce large amounts of ursodeoxycholic acid (UDCA) in their bile. UDCA is a unique component responsible for the anti-inflammatory and hepatoprotective effects exerted by bear bile. Therefore, we sought to examine the medicinal utility of nutria carcasses by investigating the hepatoprotective effect of their bile in mice. C57BL/6 mice were injected with thioacetamide (TAA), which induced liver damage by increasing Kupffer cell infiltration. Administration of nutria bile reduced hepatic inflammation, improved hepatic function, and increased the levels of senescence marker protein 30 (an indicator of hepatocyte viability). Our results show that nutria bile exerts protective effects against TAA-induced liver injury in mice, suggesting that nutria carcasses may be used for the treatment of liver injuries.

Risk stratification and treatment of primary biliary cholangitis

Primary biliary cholangitis is a chronic liver disorder characterized by progressive cholestasis that may evolve to liver cirrhosis. While ursodeoxycholic acid is the treatment of choice, around 30% of patients do not respond to this therapy. These patients have a poorer prognosis, hence should be identified early in order to be offered therapy options. Along these lines, improved understanding of the condition's pathophysiology has allowed the development of newer drugs, including obeticholic acid and fibrates. This review offers a perspective on risk stratification and treatment for these patients, from ursodeoxycholic acid to second-line treatments.

Dietary Bile Salt Types Influence the Composition of Biliary Bile Acids and Gut Microbiota in Grass Carp

Lipid metabolism can influence host’s health. There is increasing evidence for interplay between two key regulating factors in lipid metabolism: bile acids (BAs) and gut microbiota. However, very little is known about how types of different diet-supplemented bile salts (BS) influence this interaction in vivo. We sought to explore these relationships using grass carp (Ctenopharyngodon idellus), which often suffers functional disorder of liver and gallbladder. We studied fluctuations of BAs in the gall and changes of microbial communities in the gut in response to seven different diets: five different BS, chelating BS agent, and control. The BS comprised two primary BS [sodium taurochololate (TCAS) and sodium taurochenodeoxycholate (TCDCAS)], sodium tauroursodeoxycholate (TUDCAS), and two secondary BS [sodium taurodeoxycholate (TDCAS) and sodium taurolithocholate (TLCAS)]. Supplementation of primary BS caused a more significant fluctuation of biliary BAs than secondary BS, and TCAS caused a more prominent increase than TCDCAS and TUDCAS. For the gut microbiota, primary BS tended to increase their diversity and induce community succession, secondary BS resulted in a higher firmicutes/bacteroidetes ratio, while TUDCAS had no significant effects. Changes of the gut microbiota triggered by different types of BS caused alteration in BAs biotransformation. Two-obesity-associated families, Lachnospiraceae and Ruminococcaceae were positively correlated with biliary cholic acid (CA), taurochenodeoxycholic acid (TCDCA), and deoxycholic acid (DCA). As both primary and secondary BS resulted in increased synthesis of toxic secondary Bas by the gut microbiota, future studies should pay closer attention to gut microbiota when considering BA treatment.

Ursodeoxycholic acid attenuates 5-fluorouracil-induced mucositis in a rat model

Intestinal mucositis is a commonly encountered complication of chemotherapy. However, there are few effective treatments or preventive methods. Ursodeoxycholic acid (UDCA) stabilizes cell membranes, acts as an antioxidant and inhibits apoptosis, thereby exerting cytoprotective effects. The aim of the present study was to examine the ability of UDCA to protecting against chemotherapy-associated mucositis. Sprague-Dawley rats were randomly assigned to five groups: Control, vehicle + 5-fluorouracil (5-FU), 5-FU + UDCA (10 mg/kg/day), 5-FU + UDCA (100 mg/kg/day) and 5-FU + UDCA (500 mg/kg/day). Following randomization, a single dose of 5-FU was injected and varying amounts of UDCA was administered to each group. UDCA was administered orally to rats for 6 days, beginning 1 day prior to 5-FU administration. The rats were sacrificed 1 day following the last UDCA administration and intestinal tissue specimens were prepared for analysis. UDCA administration attenuated body weight loss, decreased inflammatory cytokine levels and curbed intestinal villus damage in the 10 and 100 mg/kg/day groups. When compared with the jejunal villi lengths in the vehicle+5-FU group (212.8±58.0 µm), those in the 5-FU + UDCA (10 mg/kg/day) and 5-FU + UDCA (100 mg/kg/day) groups were significantly greater [331.3±18.0 µm (P=0.001) and 310.0±112.6 µm (P=0.046), respectively]. Tumor necrosis factor-α and interleukin-6 levels were reduced in the 10 and 100 mg/kg/day UDCA groups (P<0.05). UDCA considerably attenuated the elevation in inflammatory cytokines and intestinal villus damage. The results of the study suggest that UDCA may be used as a protective agent against chemotherapy-associated intestinal mucositis.

Long-Term Ursodeoxycholic Acid Therapy Does Not Alter Lithocholic Acid Levels in Patients with Cystic Fibrosis with Associated Liver Disease

OBJECTIVE

To evaluate the fasting and postprandial serum bile acid composition in patients with cystic fibrosis-associated liver disease (CFLD) after chronic administration of ursodeoxycholic acid (UDCA) (20 mg/kg/day). The aim was to specifically focus on the extent of biotransformation of UDCA to its hepatotoxic metabolite, lithocholic acid, because of recent concerns regarding the safety of long-term, high-dose UDCA treatment for CFLD.

STUDY DESIGN

Twenty patients with CFLD (median age 16 years, range: 2.4-35.0) prescribed UDCA therapy for at least 2 years were studied. Total and individual serum bile acids were measured by stable-isotope dilution mass spectrometry, in fasting and 2-hour postprandial samples taken during chronic UDCA (20 mg/kg/day) administration.

RESULTS

During chronic UDCA administration (median duration 8 years, IQR: 6-16), UDCA became the predominant serum bile acid in all patients (median, IQR: 3.17, 1.25-5.56 μmol/L) and chenodeoxycholic acid concentrations were greater than cholic acid (1.86, 1.00-4.70 μmol/L vs 0.40, 0.24-2.71 μmol/L). The secondary bile acids, deoxycholate and lithocholate, were present in very low concentrations in fasted serum (<0.05 μmol/L). After UDCA administration, 2-hour postprandial concentrations of both UDCA and chenodeoxycholic acid significantly increased (P < .01), but no significant changes in serum lithocholic acid concentrations were observed.

CONCLUSION

These data do not support recent suggestions that enhanced biotransformation of UDCA to the hepatotoxic secondary bile acid lithocholic occurs when patients with CFLD are treated with relatively high doses of UDCA.

Novel FXR (farnesoid X receptor) modulators: Potential therapies for cholesterol gallstone disease

Metabolic disorders such as diabetes are known risk factors for developing cholesterol gallstone disease (CGD). Cholesterol gallstone disease is one of the most prevalent digestive diseases, leading to considerable financial and social burden worldwide. Ursodeoxycholic acid (UDCA) is the only bile acid drug approved by FDA for the non-surgical treatment of gallstones. However, the molecular link between UDCA and CGD is unclear. Previous data suggest that the farnesoid X receptor (FXR), a bile acid nuclear receptor, may protect against the development of CGD. In studies aimed at identifying the role of FXR, we recently identify a novel chemical tool, 6EUDCA (6-αethyl-ursodeoxycholic acid), a synthetic derivative of UDCA, for studying FXR. We found that 6EUDCA binds FXR stronger than UDCA in a TR-FRET binding assay. This result was supported by computational docking models that suggest 6EUDCA forms a more extensive hydrogen bound network with FXR. Interestingly, neither compound could activate FXR target genes in human nor mouse liver cells, suggesting UDCA and 6EUDCA activate non-genomic signals in an FXR-dependent manner. Overall these studies may lead to the identification of a novel mechanism by which bile acids regulate cell function, and 6EUDCA may be an effective targeted CGD therapeutic.

Regulation of plasma membrane localization of the Na+-taurocholate cotransporting polypeptide (Ntcp) by hyperosmolarity and tauroursodeoxycholate

In perfused rat liver, hepatocyte shrinkage induces a Fyn-dependent retrieval of the bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2) from the canalicular membrane (Cantore, M., Reinehr, R., Sommerfeld, A., Becker, M., and Häussinger, D. (2011) J. Biol. Chem. 286, 45014-45029) leading to cholestasis. However little is known about the effects of hyperosmolarity on short term regulation of the Na(+)-taurocholate cotransporting polypeptide (Ntcp), the major bile salt uptake system at the sinusoidal membrane of hepatocytes. The aim of this study was to analyze hyperosmotic Ntcp regulation and the underlying signaling events. Hyperosmolarity induced a significant retrieval of Ntcp from the basolateral membrane, which was accompanied by an activating phosphorylation of the Src kinases Fyn and Yes but not of c-Src. Hyperosmotic internalization of Ntcp was sensitive to SU6656 and PP-2, suggesting that Fyn mediates Ntcp retrieval from the basolateral membrane. Hyperosmotic internalization of Ntcp was also found in livers from wild-type mice but not in p47(phox) knock-out mice. Tauroursodeoxycholate (TUDC) and cAMP reversed hyperosmolarity-induced Fyn activation and triggered re-insertion of the hyperosmotically retrieved Ntcp into the membrane. This was associated with dephosphorylation of the Ntcp on serine residues. Insertion of Ntcp by TUDC was sensitive to the integrin inhibitory hexapeptide GRGDSP and inhibition of protein kinase A. TUDC also reversed the hyperosmolarity-induced retrieval of bile salt export pump from the canalicular membrane. These findings suggest a coordinated and oxidative stress- and Fyn-dependent retrieval of sinusoidal and canalicular bile salt transport systems from the corresponding membranes. Ntcp insertion was also identified as a novel target of β1-integrin-dependent TUDC action, which is frequently used in the treatment of cholestatic liver disease.