Ursodeoxycholic acid: Mechanism of action and novel clinical applications

Studies on the Synthesis Process of Plant-Derived Ursodeoxycholic Acid Intermediates

Ursodeoxycholic acid (UDCA), a critical secondary bile acid in human physiology, demonstrates significant industrial potential through synthetic routes from bisnoralcohol (BA). Current synthetic routes rely on hydroxyl oxidation and Horner-Wadsworth-Emmons reactions as critical initial steps, facing unresolved challenges in reaction scale-up dynamics and impurity evolution. In this work, we systematically investigated the scale-up effects and innovatively addressed the impurity control problem. In the OH-C(22) selective oxidation of BA, the impurity C(22) carboxylic acid was synthesized, the emulsification was eliminated by process optimization, and the yield was increased from 89.0% to 95.2%. In the Horner-Wadsworth-Emmons reaction, the C(20)-methyl racemate and the C(22)-Z-ene isomer were synthesized, followed by the validation of the remaining byproducts. Based on impurity profile analysis, we innovatively modified the reaction feeding protocol, increased the yield from 79.1% to 90.8%, and significantly improved reaction selectivity. This optimized process demonstrates superior scalability and provides valuable insights for the industrial production of plant-derived UDCA.

The effect of ursodeoxycholic acid in dissolving gallstones formed after laparoscopic sleeve gastrectomy: retrospective cohort study

PURPOSE

Rapid weight loss that often occurs after laparoscopic sleeve gastrectomy (LSG) has been linked to an increased risk of gallstone formation. This study aimed to investigate whether ursodeoxycholic acid could be an effective alternative treatment for gallstone dissolution, potentially offering a nonsurgical option for patients requiring gallstone removal.

METHODS

This retrospective study analyzed 88 patients who underwent LSG and subsequently developed gallstones between 2017 and 2023. Fifty-one patients who received UDCA treatment were compared to 37 patients who did not receive UDCA. Demographic and clinical characteristics and gallstone dissolution rates were analyzed using SPSS v25.0.

RESULTS

Gallstones dissolved in 60% of patients who received UDCA treatment, and symptoms such as dyspepsia decreased. A stone diameter of less than 5 mm was associated with a higher treatment success rate. The number of hospitalizations and admissions due to gallstone symptoms has decreased. The side effects were mild and did not require treatment discontinuation.

CONCLUSIONS

UDCA treatment is an effective option for the resolution of gallstones after LSG. However, surgery may be more appropriate for treating larger stones. The results of this study suggest that UDCA is an effective intervention for reducing gallstone-related complications following LSG.

Gut Metabolome in Companion Animal Nutrition-Linking Diets to Health

Tailoring diet to support a healthy gut microbiome is key for animal well-being. The gut metabolome, including all small molecules in the gut, is central to diet-microbiome-health interactions. While comprehension of the gut metabolome in companion animal nutrition is emerging, a substantial number of studies have been undertaken to elucidate the metabolomic shifts and identify specific marker metabolites influenced by diverse dietary interventions. By employing various metabolomic approaches, researchers have extensively documented the effects of different diet types, nutrient compositions, and dietary supplements on the gut metabolome in dogs and cats. Despite these advancements, there remains several notable limitations, including a lack of integrated microbiome analysis, incomplete understanding of specific marker metabolites, and an over-reliance on extrapolating findings from human studies. Therefore, this review aims to summarize the current understanding of the canine and feline gut metabolome, while exploring future possibilities and challenges for the field.

Bi-Directional Relationship Between Bile Acids (BAs) and Gut Microbiota (GM): UDCA/TUDCA, Probiotics, and Dietary Interventions in Elderly People

The gut microbiota (GM), the set of microorganisms that colonizes our intestinal tract, can undergo many changes, some of which are age related. Several studies have shown the importance of maintaining a healthy GM for a good quality of life. In the elderly, maintaining a good GM may become a real defense against infection by pathogens, such as C. difficile. In addition to the GM, bile acids (BAs) have been shown to provide an additional defense mechanism against the proliferation of pathogenic bacteria and to regulate bacterial colonization of the gut. BAs are molecules produced in the host liver and secreted with the bile into the digestive tract, and they are necessary for the digestion of dietary lipids. In the gut, host-produced BAs are metabolized by commensal bacteria to secondary BAs. In general GM and host organisms interact in many ways. This review examines the relationship between GM, BAs, aging, and possible new approaches such as dietary interventions, administration of ursodesoxycholic acid/tauroursodesoxycholic acid (UDCA/TUDCA), and probiotics to enrich the microbial consortia of the GM in the elderly and achieve a eubiotic state necessary for maintaining good health. The presence of Firmicutes and Actinobacteria together with adequate levels of secondary BAs would provide protection and improve the frailty state in the elderly. In fact, an increase in secondary BAs has been observed in centenarians who have reached old age without serious health issues, which may justify their active role in achieving longevity.

Synthesis of TUDCA from chicken bile: immobilized dual-enzymatic system for producing artificial bear bile substitute

Bear bile, a valuable animal-derived medicinal substance primarily composed of tauroursodeoxycholic acid (TUDCA), is widely distributed in the medicinal market across various countries due to its significant therapeutic potential. Given the extreme cruelty involved in bear bile extraction, researchers are focusing on developing synthetic bear bile powder as a more humane alternative. This review presents an industrially practical and environmentally friendly process for producing an artificial substitute for bear bile powder using inexpensive and readily available chicken bile powder through an immobilized 7α-,7β-HSDH dual-enzymatic syste. Current technology has facilitated the industrial production of TUDCA from Tauodeoxycholic acid (TCDCA) using chicken bile powder. The review begins by examining the chemical composition, structure, and properties of bear bile, followed by an outline of the pharmacological mechanisms and manufacturing methods of TUDCA, covering chemical synthesis and biotransformation methods, and a discussion on their respective advantages and disadvantages. Finally, the process of converting chicken bile powder into bear bile powder using an immobilized 7α-Hydroxysteroid Dehydrogenases(7α-HSDH) with 7β- Hydroxysteroid Dehydrogenases (7β-HSDH) dual-enzyme system is thoroughly explained. The main objective of this review is to propose a comprehensive strategy for the complete synthesis of artificial bear bile from chicken bile within a controlled laboratory setting.

Ursodeoxycholic acid ameliorates erectile dysfunction and corporal fibrosis in diabetic rats by inhibiting the TGF-β1/Smad2 pathway

Corporal tissue fibrosis is critical in diabetes-associated erectile dysfunction. Transforming growth factor-β1/Small mothers against decapentaplegic-2 (TGF-β1/Smad2) contributes to the induction of fibrosis in corporal tissue. Smad7 is accepted as a general negative regulator of Smad signaling, although its role in corporal fibrosis is unknown. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid used for biliary and liver related disorders and has antifibrotic effects in the liver. This study investigated the effects of UDCA on diabetic erectile dysfunction. Forty-eight male Spraque Dawley rats were divided into six groups: nondiabetic (n = 6), nondiabetic+20 mg/kg UDCA (n = 6), nondiabetic+80 mg/kg UDCA (n = 6), diabetic (n = 10), diabetic+20 mg/kg UDCA (n = 10), diabetic+80 mg/kg UDCA (n = 10). Diabetes was induced by intraperitoneal injection of 60 mg/kg Streptozocin. UDCA (20 and 80 mg/kg/day) or saline was subsequently administered via oral gavage for 56 days. Erectile function was evaluated as measurement of maximum intracavernosal pressure (m-ICP)/mean arterial pressure (MAP) and total ICP/MAP. Corporal tissues were evaluated by Western blotting and Masson's trichrome staining. Electrical stimulation-induced m-ICP/MAP responses were higher in UDCA-treated diabetic rats compared to untreated diabetic rats, respectively (20 mg/kg; 4 V: 0.77 ± 0.11 vs 0.45 ± 0.09, p = 0.0001 and 80 mg/kg; 4 V: 0.78 ± 0.11 vs 0.45 ± 0.09, p = 0.0001) UDCA prevented the increase in phospho-Smad2 and fibronectin protein expressions in diabetic corporal tissue both at 20 mg/kg (p = 0.0002, p = 0.002 respectively) and 80 mg/kg doses (p < 0.0001 for both). Smad7 protein expressions were significantly increased in the UDCA-treated diabetic groups compared to the untreated diabetic group (20 mg/kg: p = 0.0079; 80 mg/kg: p = 0.004). Furthermore, UDCA significantly prevented diabetes-induced increase in collagen (20 mg/kg: p = 0.0172; 80 mg/kg: p = 0.0003) and smooth muscle loss (20 mg/kg: p = 0.044; 80 mg/kg: p = 0.039). In conclusion, UDCA has a potential protective effect on erectile function in diabetic rats by altering fibrotic pathways via inhibition of TGF-β1/Smad2 and activation of Smad7.

Engineering of a hydroxysteroid dehydrogenase with simultaneous enhancement in activity and thermostability for efficient biosynthesis of ursodeoxycholic acid

Hydroxysteroid dehydrogenases (HSDHs) catalyze the oxidation/reduction of hydroxyl/keto groups of steroids with high regio- or stereoselectivity, playing an essential role in producing optically pure chemicals. In this work, a novel approach was developed to simultaneously improve the stability and activity of 7β-hydroxysteroid dehydrogenase (7β-HSDH) by combining B-factor analysis and computer-aided prediction. Several advantageous mutants were identified, and the most promising variant, S51Y/P202Y, exhibited 2.3-fold improvements in catalytic activity, 3.3-fold in half-life at 40°C, and 4.7-fold in catalytic efficiency (kcat/Km), respectively. Structural modeling analysis showed that the shortened reversible oxidation reaction catalytic distance and the strengthened residue interactions compared to the wild type were attributed to the improved stability and activity of the obtained mutants. To synthesize ursodeoxycholic acid cost-effectively by mutant S51Y/P202Y, a NAD-kinase was employed to facilitate the substitution of nicotinamide adenine dinucleotide phosphate (NADP+) with nicotinamide adenine dinucleotide (NAD+) in the whole-cell catalysis system. The substrate 7-ketolithocholic acid (100 mM) was converted completely in 0.5 h, achieving a space-time yield of 1,887.3 g L-1 d-1. This work provided a general target-oriented strategy for obtaining stable and highly active dehydrogenase for efficient biosynthesis.

IMPORTANCE

Hydroxysteroid dehydrogenases have emerged as indispensable tools in the synthesis of steroids, bile acids, and other steroid derivatives for the pharmaceutical and chemical industries. In this study, a novel approach was developed to simultaneously improve the stability and activity of a hydroxysteroid dehydrogenase by combining B-factor analysis and computer-aided prediction. This semi-rational method was demonstrated to be highly effective for enzyme engineering. In addition, NAD kinase was introduced to convert NAD+ to NADP+ for effective coenzyme regeneration in the whole-cell multienzyme-catalyzed system. This strategy reduces the significant economic costs associated with externally supplemented cofactors in NADP-dependent biosynthetic pathways.

Deciphering the role of the major histocompatibility complex, the intestinal microbiome and metabolites in the pathogenesis of acute graft-versus-host disease

Allogeneic hematologic stem cell transplantation is a cornerstone in modern hematological treatment, yet its efficacy is compromised by acute Graft-versus-Host Disease. In acute Graft-versus-Host Disease, conditioning regimen induced epithelial damage leads to release of damage and pathogen associated molecular patters which in turns triggers activation of alloreactive donor T cells, ultimately resulting in destruction of healthy tissue. Advances in major histocompatibility complex typing and preclinical studies using tissue specific major histocompatibility complex deletion have illuminated the contributions of both, hematopoietic and non-hematopoietic cells to acute Graft-versus-Host Disease pathophysiology. Concurrently, high-throughput sequencing techniques have enabled researchers to recognize the significant impact of the intestinal microbiome and newly discovered metabolites in the pathophysiology of acute Graft-versus-Host Disease. In this review, we discuss the implications of major histocompatibility complex expression on hematopoietic and non-hematopoietic cells, the effect on the intestinal microbiome and the metabolic alterations that contribute to acute Graft-versus-Host Disease. By combining these findings, we hope to untangle the complexity of acute Graft-versus-Host Disease, ultimately paving the way for the development of novel and more effective treatmen options in patients.

Ursodeoxycholic acid may protect from severe acute respiratory syndrome coronavirus 2 Omicron variant by reducing angiotensin-converting enzyme 2

The SARS-CoV-2 caused COVID-19 pandemic has posed a global health hazard. While some vaccines have been developed, protection against viral infection is not perfect because of the urgent approval process and the emergence of mutant SARS-CoV-2 variants. Here, we employed UDCA as an FXR antagonist to regulate ACE2 expression, which is one of the key pathways activated by SARS-CoV-2 Delta variant infection. UDCA is a well-known reagent of liver health supplements and the only clinically approved bile acid. In this paper, we investigated the protective efficacy of UDCA on Omicron variation, since it has previously been verified for protection against Delta variant. When co-housing with an Omicron variant-infected hamster group resulted in spontaneous airborne transmission, the UDCA pre-supplied group was protected from weight loss relative to the non-treated group at 4 days post-infection by more than 5%-10%. Furthermore, UDCA-treated groups had a 3-fold decrease in ACE2 expression in nasal cavities, as well as reduced viral expressing genes in the respiratory tract. Here, the data show that the UDCA serves an alternative option for preventive drug, providing SARS-CoV-2 protection against not only Delta but also Omicron variant. Our results of this study will help to propose drug-repositioning of UDCA from liver health supplement to preventive drug of SARS-CoV-2 infection.

Ursodeoxycholic acid production by Gibberella zeae mutants

Ursodeoxycholic acid (UDCA) is a highly demanded pharmaceutical steroid widely used in medicine. An ascomycete Gibberella zeae VKM F-2600 is capable of producing UDCA by 7β-hydroxylation of lithocholic acid (LCA). The present study is aimed at the improvement of the fungus productivity. The original procedures for the protoplast obtaining followed by UV mutagenesis and screening of ketoconazole-resistant mutant clones have been applied. The highest yield of G. zeae protoplasts was obtained when using the mycelium in the active growth phase, ammonium chloride as an osmotic stabilizer and treatment of the fungal cells by the lytic enzymes cocktail from Trichoderma hurzanium. The conditions for effective protoplast regeneration and the UV-mutagenesis were found to provide 6–12% survival rate of the protoplasts with superior number of possible mutations. Three of 27 ketoconazole-resistant mutant clones obtained have been selected due to their increased biocatalytic activity towards LCA. The mutant G. zeae M23 produced 26% more UDCA even at relatively high LCA concentration (4 g/L) as compared with parent fungal strain, and the conversion reached 88% (w/w). The yield of UDCA reached in this study prefers those ever reported. The results contribute to the knowledge on ascomycete mutagenesis, and are of importance for biotechnological production of value added cholic acids.

Efficient procedures for production and regeneration of Gibberella zeae protoplasts were determined.

Fungal mutants were obtained with elevated 7β-hydroxylase activity.

Mutant G. zeae M23 almost fully converts LCA (4 g/L) to UDCA.

Sex-, age-, and organ-dependent improvement of bile acid hydrophobicity by ursodeoxycholic acid treatment: A study using a mouse model with human-like bile acid composition

Cyp2a12^-/-Cyp2c70^-/- double knockout (DKO) mice have a human-like hydrophobic bile acid (BA) composition and show reduced fertility and liver injury. Ursodeoxycholic acid (UDCA) is a hydrophilic and cytoprotective BA used to treat various liver injuries in humans. This study investigated the effects of orally administered UDCA on fertility and liver injury in DKO mice. UDCA treatment prevented abnormal delivery (miscarriage and preterm birth) in pregnant DKO mice, presumably by increasing the hydrophilicity of serum BAs. UDCA also prevented liver damage in six-week-old DKO mice, however liver injury emerged in UDCA-treated 20-week-old female, but not male, DKO mice. In 20-week-old male UDCA-treated DKO mice, conjugated plus unconjugated UDCA proportions in serum, liver, and bile were 71, 64, and 71% of the total BAs, respectively. In contrast, conjugated plus unconjugated UDCA proportions in serum, liver, and bile of females were 56, 34, and 58% of the total BAs, respectively. The UDCA proportion was considerably low in female liver only and was compensated by highly hydrophobic lithocholic acid (LCA). Therefore, UDCA treatment markedly reduced the BA hydrophobicity index in the male liver but not in females. This appears to be why UDCA treatment causes liver injury in 20-week-old female mice. To explore the cause of LCA accumulation in the female liver, we evaluated the hepatic activity of CYP3A11 and SULT2A1, which metabolize LCAs to more hydrophilic BAs. However, there was no evidence to suggest that either enzyme activity was lower in females than in males. As female mice have a larger BA pool than males, excessive loading of LCAs on the hepatic bile salt export pump (BSEP) may be the reason for the hepatic accumulation of LCAs in female DKO mice with prolonged UDCA treatment. Our results suggest that the improvement of BA hydrophobicity in DKO mice by UDCA administration is sex-, age-, and organ-dependent.

The Role of Ursodeoxycholic Acid and Phenobarbital in a Child with Cholestasis: A Longitudinal Study

BACKGROUND: Cholestasis is a condition that starts in the 1st months of life and progresses with direct (conjugated) bilirubin increase and jaundice as a result of impaired bile production or excretion. Its incidence is known as 1 in 2500 live births. This study shows the effectiveness of ursodeoxycholic acid (UDCA) and phenobarbital in infant cholestasis treatment. CASE REPORT: A 28-days-old boy came with a complaint of yellow eyes. At the age of 3 days, the patient looked yellow, had a fever and difficulty drinking, received phototherapy. After 2 weeks of treatment with neonatal sepsis, the patient was discharged in a stable. The skin appears yellow. The laboratory results show anemia, elevated conjugated bilirubin, and signs of infection; the abdominal ultrasonography shows that the liver and gallbladder were normal. The diagnosis is cholestasis due to sepsis. After 3 months of treatment with UDCA and phenobarbital, jaundiced disappeared, and liver function tests were normal. When the patient is 2 ½ years old, the growth and development suit his age. CONCLUSION: Early diagnosis and timely treatment of UDCA and phenobarbital play a role in cholestasis improvement. On long-term observation, the child’s growth and development are suitable according to his age and average laboratory results.

Compartmentalized cross-linked enzyme nano aggregates (c-CLEnAs) toward pharmaceutical transformations

A new immobilization strategy using compartmentalized nanoreactors is herein reported for two biocatalytic processes: (1) N-acetylneuraminate lyase (NAL) is internalized in NAL-c-CLEnAs and used in a continuous flow aldol condensation of N-acetyl-d-mannosamine with sodium pyruvate to N-acetylneuraminic acid; (2) two hydroxysteroid dehydrogenases (HSDH) 7α- and 7β-HSDH are incorporated in c-CLEnAs and used in a two-step cascade batch synthesis of ursodeoxycholic acid (UDCA). The versatile use of c-CLEnA demonstrates that this immobilization methodology is a valuable addition to the toolbox of synthetic chemists.

Secondary bile acid ursodeoxycholic acid alters weight, the gut microbiota, and the bile acid pool in conventional mice

Ursodeoxycholic acid (commercially available as ursodiol) is a naturally occurring bile acid that is used to treat a variety of hepatic and gastrointestinal diseases. Ursodiol can modulate bile acid pools, which have the potential to alter the gut microbiota community structure. In turn, the gut microbial community can modulate bile acid pools, thus highlighting the interconnectedness of the gut microbiota-bile acid-host axis. Despite these interactions, it remains unclear if and how exogenously administered ursodiol shapes the gut microbial community structure and bile acid pool in conventional mice. This study aims to characterize how ursodiol alters the gastrointestinal ecosystem in conventional mice. C57BL/6J wildtype mice were given one of three doses of ursodiol (50, 150, or 450 mg/kg/day) by oral gavage for 21 days. Alterations in the gut microbiota and bile acids were examined including stool, ileal, and cecal content. Bile acids were also measured in serum. Significant weight loss was seen in mice treated with the low and high dose of ursodiol. Alterations in the microbial community structure and bile acid pool were seen in ileal and cecal content compared to pretreatment, and longitudinally in feces following the 21-day ursodiol treatment. In both ileal and cecal content, members of the Lachnospiraceae Family significantly contributed to the changes observed. This study is the first to provide a comprehensive view of how exogenously administered ursodiol shapes the healthy gastrointestinal ecosystem in conventional mice. Further studies to investigate how these changes in turn modify the host physiologic response are important.

Primary Biliary Cholangitis and Bile Acid Farnesoid X Receptor Agonists

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by the progressive destruction of the intrahepatic bile ducts. Currently, the first line drug for PBC is ursodeoxycholic acid (UDCA) characterized by anti-apoptotic, anti-inflammatory and protective actions on cholangiocytes. Despite its recognized therapeutic action, 30-40% of PBC patients only partially benefit from UDCA therapy. This has led to the identification of the role of the farnesoid x receptor (FXR) in cholestatic liver diseases and, consequently, to the development of obeticholic acid (OCA), a steroid FXR agonist that has been recently approved for the treatment of PBC. OCA though is not effective in all patients and can cause itch, which eventually induces treatment drop out. Therefore, the search for new therapeutic strategies for PBC has begun. This review, in addition to summarizing the current treatments for PBC, provides overview of the chemical characteristics of new steroid FXR agonist candidates that could represent a future perspective for the treatment of PBC.

Ursodeoxycholic Acid (UDCA) Mitigates the Host Inflammatory Response during Clostridioides difficile Infection by Altering Gut Bile Acids

Clostridioides difficile infection (CDI) is associated with increasing morbidity and mortality posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this enteric pathogen. Administration of the secondary bile acid ursodeoxycholic acid (UDCA; ursodiol) inhibits the life cycles of various strains of C. difficile in vitro, suggesting that the FDA-approved formulation of UDCA, known as ursodiol, may be able to restore colonization resistance against C. difficile in vivo However, the mechanism(s) by which ursodiol is able to restore colonization resistance against C. difficile remains unknown. Here, we confirmed that ursodiol inhibits C. difficile R20291 spore germination and outgrowth, growth, and toxin activity in a dose-dependent manner in vitro In a murine model of CDI, exogenous administration of ursodiol resulted in significant alterations in the bile acid metabolome with little to no changes in gut microbial community structure. Ursodiol pretreatment resulted in attenuation of CDI pathogenesis early in the course of disease, which coincided with alterations in the cecal and colonic inflammatory transcriptome, bile acid-activated receptors nuclear farnesoid X receptor (FXR) and transmembrane G-protein-coupled membrane receptor 5 (TGR5), which are able to modulate the innate immune response through signaling pathways such as NF-κB. Although ursodiol pretreatment did not result in a consistent decrease in the C. difficile life cycle in vivo, it was able to attenuate an overly robust inflammatory response that is detrimental to the host during CDI. Ursodiol remains a viable nonantibiotic treatment and/or prevention strategy against CDI. Likewise, modulation of the host innate immune response via bile acid-activated receptors FXR and TGR5 represents a new potential treatment strategy for patients with CDI.

Dihydroartemisinin-Bile Acid Hybridization as an Effective Approach to Enhance Dihydroartemisinin Anticancer Activity

A series of hybrid compounds based on natural products-bile acids and dihydroartemisinin-were prepared by different synthetic methodologies and investigated for their in vitro biological activity against HL-60 leukemia and HepG2 hepatocellular carcinoma cell lines. Most of these hybrids presented significantly improved antiproliferative activities with respect to dihydroartemisinin and the parent bile acid. The two most potent hybrids of the series exhibited a 10.5- and 15.4-fold increase in cytotoxic activity respect to dihydroartemisinin alone in HL-60 and HepG2 cells, respectively. Strong evidence that an ursodeoxycholic acid hybrid induced apoptosis was obtained by flow cytometric analysis and western blot analysis.

Bezafibrate Improves GLOBE and UK-PBC Scores and Long-Term Outcomes in Patients With Primary Biliary Cholangitis

In Japan, bezafibrate (BF) is a second-line agent for primary biliary cholangitis (PBC) that is refractory to ursodeoxycholic acid (UDCA) treatment. From a retrospective cohort (n = 873) from the Japan PBC Study Group, we enrolled 118 patients who had received UDCA monotherapy for at least 1 year followed by combination therapy with UDCA+BF for at least 1 year. GLOBE and UK-PBC scores after UDCA monotherapy (i.e., immediately before UDCA+BF combination therapy) were compared with those after 1 year of UDCA+BF combination therapy. The real outcomes of enrolled patients estimated by Kaplan-Meier analysis were compared with the predicted outcomes calculated using GLOBE and UK-PBC scores. In addition, the hazard ratio of BF treatment was calculated using propensity score analysis. The mean GLOBE score before the combination therapy was 0.504 ± 0.080, which improved significantly to 0.115 ± 0.085 (P < 0.0001) after 1 year of combination therapy. The real liver transplant-free survival of enrolled patients was significantly better than that predicted by GLOBE score before introducing BF. Combination therapy did not significantly improve the real rates of liver transplantation or liver-related death compared with those predicted by UK-PBC risk score before introducing BF, but the predicted risk was significantly reduced by the addition of BF (P < 0.0001). Cox regression analysis with inverse probability of treatment weighting showed that the addition of BF significantly reduced the hazard of liver transplant or liver-related death in patients who, after 1 year of UDCA monotherapy, had normal serum bilirubin (adjusted hazard ratio 0.09, 95% confidence interval 0.01-0.60, P = 0.013). Conclusion: Addition of BF to UDCA monotherapy improves not only GLOBE and UK-PBC scores but also the long-term prognosis of PBC patients, especially those with early-stage PBC.

Diversification of host bile acids by members of the gut microbiota

Bile acid biotransformation is a collaborative effort by the host and the gut microbiome. Host hepatocytes synthesize primary bile acids from cholesterol. Once these host-derived primary bile acids enter the gastrointestinal tract, the gut microbiota chemically modify them into secondary bile acids. Interest into the gut-bile acid-host axis is expanding in diverse fields including gastroenterology, endocrinology, oncology, and infectious disease. This review aims to 1) describe the physiologic aspects of collaborative bile acid metabolism by the host and gut microbiota; 2) to evaluate how gut microbes influence bile acid pools, and in turn how bile acid pools modulate the gut microbial community structure; 3) to compare species differences in bile acid pools; and lastly, 4) discuss the effects of ursodeoxycholic acid (UDCA) administration, a common therapeutic bile acid, on the gut microbiota-bile acid-host axis.

Discovery of a Novel Selective Dual Peroxisome Proliferator-Activated Receptor α/δ Agonist for the Treatment of Primary Biliary Cirrhosis

A novel peroxisome proliferator-activated receptor (PPAR) α/δ dual agonist 5c was developed with an EC50 of 8 nM for PPARα, 5 nM for PPARδ, and >300-fold selectivity against PPARγ (EC50 = 2939 nM), respectively. Further ADME and pharmacokinetic studies indicated 5c possessed distinguished in vitro and in vivo profiles. The excellent in vivo efficacy of compound 5c was demonstrated by the rat primary biliary cirrhosis (PBC) model.

NAD+ -Dependent Enzymatic Route for the Epimerization of Hydroxysteroids

Epimerization of cholic and chenodeoxycholic acid (CA and CDCA, respectively) is a notable conversion for the production of ursodeoxycholic acid (UDCA). Two enantiocomplementary hydroxysteroid dehydrogenases (7α- and 7β-HSDHs) can carry out this transformation fully selectively by specific oxidation of the 7α-OH group of the substrate and subsequent reduction of the keto intermediate to the final product (7β-OH). With a view to developing robust and active biocatalysts, novel NADH-active 7β-HSDH species are necessary to enable a solely NAD+ -dependent redox-neutral cascade for UDCA production. A wild-type NADH-dependent 7β-HSDH from Lactobacillus spicheri (Ls7β-HSDH) was identified, recombinantly expressed, purified, and biochemically characterized. Using this novel NAD+ -dependent 7β-HSDH enzyme in combination with 7α-HSDH from Stenotrophomonas maltophilia permitted the biotransformations of CA and CDCA in the presence of catalytic amounts of NAD+ , resulting in high yields (>90 %) of UCA and UDCA.

Effect of 4-Phenylbutyric Acid and Tauroursodeoxycholic Acid on Magnesium and Calcium Metabolism in Streptozocin-Induced Type 1 Diabetic Mice

Recent evidence has identified a role of micronutrients, such as magnesium (Mg2+) and calcium (Ca2+), in glycemic control. 4-Phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) are molecular chaperones that can improve protein folding and alleviate endoplasmic reticulum (ER) stress. Increasingly, research is focusing on the association between molecular chaperones and micronutrients. This study established and characterized a mouse model of type 1 diabetes (T1D) and investigated the effect of PBA and TUDCA on Mg2+ and Ca2+ metabolism in these mice. T1D was established in Friend virus B-type mice using multiple low doses of streptozotocin. Mice were administered chaperones. Mg2+and Ca2+ levels in tissues and serum were detected using acid digestion and ICP-MS. At 2 weeks and 2 months after chaperone administration was initiated, Mg2+ levels in the heart, liver, kidney, and serum and Ca2+ levels in spleen and serum of T1D mice were significantly decreased compared with controls; Ca2+ levels in the kidney and muscle of T1D mice were significantly increased; Mg2+ and Ca2+ levels in the heart, liver, kidney, muscle, spleen, and serum were positively correlated in control and T1D mice; and PBA restored renal Mg2+ levels to normal values and TUDCA restored hepatic, renal, and serum Mg2+ levels and renal and serum Ca2+ levels to normal values in T1D mice. PBA restored muscular Ca2+ levels to normal values in T1D mice at 2 months after chaperone or vehicle administration was initiated. Further research is required to investigate the underlying mechanisms by which chaperones regulate micronutrients in diabetes.

Asymptomatic giant cell hepatitis: a subtype of post-infantile giant cell hepatitis?

Giant cell hepatitis in adults is considered a rapidly progressive and life-threatening disease, but there are few descriptions of a prolonged disease course. A 36-year-old Japanese man was referred to our hospital for further evaluation of abnormal liver function test results. Although asymptomatic, he had undergone follow-up for 9 years with these abnormalities. Because the cause of liver injury was not identified despite extensive noninvasive examinations, the patient underwent needle biopsy. He was finally diagnosed with post-infantile giant cell hepatitis (PIGCH) based on the presence of small numbers of giant multinucleated hepatocytes scattered primarily around the portal area. Necroinflammatory changes were very mild in the portal tracts and hepatic parenchyma. According to the histological findings as well as the accepted international diagnostic scoring system for autoimmune hepatitis (AIH), which is closely related to PIGCH, AIH was unlikely, although antinuclear antibody was positive at a titer of 1:160. The present case may describe an unknown subtype of PIGCH, characterized by insidious disease onset and progression with concurrent, mildly active underlying hepatitis, which is in contrast with the well-documented aggressive nature of PIGCH.

Human-specific dual regulations of FXR-activation for reduction of fatty liver using in vitro cell culture model

Nuclear receptor farnesoid X receptor activation inhibits fatty acid synthesis through the liver X receptor-α-sterol regulatory element binding protein-1c pathway universally in animals, but also has human-specific crosstalk with the peroxisome proliferator-activated receptor-α. The effects of farnesoid X receptor-ligands on both the synthesis and degradation of fatty liver through nuclear receptor-related regulation were investigated in both human and murine hepatocytes. A fatty liver culture cell model was established using a synthetic liver X receptor-α-ligand (To901317) for both human and mouse non-neoplastic hepatocytes. The hepatocytes were exposed to natural or synthetic farnesoid X receptor-ligands (bile acids, GW4064, obeticholic acid) together with or after To901317. Cellular triglyceride accumulation was significantly inhibited by the farnesoid X receptor-ligands along with inhibition of lipogenic genes and up-regulation of farnesoid X receptor-target small heterodimer partner in both human and mouse cells. The accumulated triglyceride was significantly degraded by the farnesoid X receptor-ligands only in the human cells accompanied with the up-regulations of peroxisome proliferator-activated receptor-α and fatty acid β-oxidation. Farnesoid X receptor-ligands can be therapeutic agents for treating human fatty liver through dual effects on inhibition of lipogenesis and on enhancement of lipolysis.

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

Ursodeoxycholic acid (UDCA) is a pharmaceutical ingredient widely used in clinics. As bile acid it solubilizes cholesterol gallstones and improves the liver function in case of cholestatic diseases. UDCA can be obtained from cholic acid (CA), which is the most abundant and least expensive bile acid available. The now available chemical routes for the obtainment of UDCA yield about 30% of final product. For these syntheses several protection and deprotection steps requiring toxic and dangerous reagents have to be performed, leading to the production of a series of waste products. In many cases the cholic acid itself first needs to be prepared from its taurinated and glycilated derivatives in the bile, thus adding to the complexity and multitude of steps involved of the synthetic process. For these reasons, several studies have been performed towards the development of microbial transformations or chemoenzymatic procedures for the synthesis of UDCA starting from CA or chenodeoxycholic acid (CDCA). This promising approach led several research groups to focus their attention on the development of biotransformations with non-pathogenic, easy-to-manage microorganisms, and their enzymes. In particular, the enzymatic reactions involved are selective hydrolysis, epimerization of the hydroxy functions (by oxidation and subsequent reduction) and the specific hydroxylation and dehydroxylation of suitable positions in the steroid rings. In this minireview, we critically analyze the state of the art of the production of UDCA by several chemical, chemoenzymatic and enzymatic routes reported, highlighting the bottlenecks of each production step. Particular attention is placed on the precursors availability as well as the substrate loading in the process. Potential new routes and recent developments are discussed, in particular on the employment of flow-reactors. The latter technology allows to develop processes with shorter reaction times and lower costs for the chemical and enzymatic reactions involved.

Ursodeoxycholic acid inhibits the proliferation of colon cancer cells by regulating oxidative stress and cancer stem-like cell growth

INTRODUCTION

The regulation of reactive oxygen species (ROS) exists as a therapeutic target for cancer treatments. Previous studies have shown that ursodeoxycholic acid (UDCA) suppresses the proliferation of colon cancer cells. The aim of this study was to evaluate the effect of UDCA upon the proliferation of colon cancer cells as a direct result of the regulation of ROS.

METHOD

Colon cancer cell lines (HT29 and HCT116) were treated with UDCA. The total number of cells and the number of dead cells were determined using cell counters. A fluorescein isothiocyanate-bromodeoxyuridine flow kit was used to analyze cell cycle variations. Upon exposure to UDCA, the protein levels of p27, p21, CDK2, CDK4 and CDK6 were determined using western blotting, and qRT-PCR was used to determine levels of mRNA. We preformed dichlorofluorescindiacetate (DCF-DA) staining to detect alteration of intracellular ROS using fluorescence activated cell sorting (FACS). Colon cancer stem-like cell lines were generated by tumorsphere culture and treated with UDCA for seven days. The total number of tumorspheres was determined using microscopy.

RESULTS

We found that UDCA reduced the total number of colon cancer cells, but did not increase the number of dead cells. UDCA inhibited the G1/S and G2/M transition phases in colon cancer cells. UDCA induced expression of cell cycle inhibitors such as p27 and p21. However, it was determined that UDCA suppressed levels of CDK2, CDK4, and CDK6. UDCA regulated intracellular ROS generation in colon cancer cells, and induced activation of Erk1/2. Finally, UDCA inhibited formation of colon cancer stem-like cells.

CONCLUSION

Our results indicate that UDCA suppresses proliferation through regulation of oxidative stress in colon cancer cells, as well as colon cancer stem-like cells.

[Nonalcoholic steatohepatitis and biliary sludge in people with metabolic syndrome]

AIM

To determine the incidence of biliary sludge (BS) and to evaluate the clinical efficacy of Chophytol in patients with nonalcoholic steatohepatitis (NASH) and BS in the presence of metabolic syndrome (MS).

SUBJECTS AND METHODS

Clinical laboratory examination was made in 72 patients with NASH in the presence of MS. BS was identified in 52 (72.2%) examinees who were divided in two (study and control) groups. The efficacy of Chophytol of plant origin, prepared from the purified extract of fresh artichoke (Cynara scolymus) leaf juice, which was used at a dose of 3 tablets thrice daily for a month, was evaluated.

RESULTS

The use of Chophytol was established to promote BS elimination in 87% of the patients. This ceased pain syndrome in 87% and dyspeptic manifestations in 65.2% and normalized the levels of lipids and the biochemical indicators of liver process activity. No adverse drug reactions were seen.

CONCLUSION

Chophytol used in patients with HASH and BS may soon be possible to make general condition better, to alleviate the symptoms of diseases of the liver and biliary system, and to appreciably improve the biochemical indicators of blood and bile.

Efficacy and safety of ursodeoxycholic acid composite on fatigued patients with elevated liver function and/or fatty liver: a multi-centre, randomised, double-blinded, placebo-controlled trial

AIM

The aim of this study was to assess the effects of ursodeoxycholic acid composite (URSA-S) on fatigue in patients with elevated liver function tests and/or fatty liver disease.

METHODS

In this multi-centre randomised double-blinded placebo-controlled trial, 168 adults who were diagnosed with fatigue based on our criteria and had elevated liver function tests (but not > 5 times the normal level) and/or fatty liver on ultrasonography, were randomised to either the placebo or URSA-S administration group. The rate of improvement of checklist individual strength (CIS) using a cut-off of 76 points at the end of the study (8 weeks), the change in fatigue scale [CIS score and visual analogue scale (VAS)] were evaluated. The adverse effects of URSA-S were also recorded.

RESULTS

The rate of CIS improvement at the end-point was 79.76% and 45.68% in the therapy and placebo groups, respectively (p < 0.05). The fatigue recovery rate of the CIS score and VAS were higher in the therapy (-25.44 ± 18.57, -27.84 ± 2.70) than in the placebo group (-16.59 ± 17.29, -19.46 ± 2.81) (p < 0.05). The difference in fatigue recovery rate between the therapy and placebo groups was significant after 8 weeks. When analysed separately in patients with abnormal liver function tests and fatty liver disease, the fatigue recovery rate of the CIS score and VAS at 8 weeks was higher in the therapy than in the placebo group (p < 0.05). The frequency of adverse events in the therapy group was not significantly higher than that in the placebo group.

CONCLUSION

URSA-S is effective for alleviating fatigue in patients with liver dysfunction and/or fatty liver. The adverse effects of URSA-S are not significant. This study is registered at https://clinicaltrials.gov/ct2/show/NCT02415777.

Effect of Tauroursodeoxycholic Acid and 4-Phenylbutyric Acid on Metabolism of Copper and Zinc in Type 1 Diabetic Mice Model

Alternations of copper (Cu) and zinc (Zn) status in diabetes have received a great attention. Tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (PBA) could alleviate the increased endoplasmic reticulum (ER) stress and prevent insulin resistance. This study aimed to investigate the effect of TUDCA and PBA on metabolism of Cu and Zn in diabetic mice model. Diabetes was induced by streptozotocin in FVB mice treated with and without TUDCA and PBA. Determination of Cu and Zn in tissues and serum by acid digestion was followed by ICP-MS. The renal and serum Cu levels were significantly higher, while the hepatic Cu and Zn levels were significantly decreased in the diabetic mice at 2 weeks and 2 months after diabetes onset. The increase of cardiac Cu together with the decrease of muscular Zn was found in the diabetic mice only at 2 months. Cu levels were positively correlated with Zn in the heart, liver, kidney, muscle, spleen, and serum of diabetic and control mice at both 2 weeks and 2 months. Both PBA and TUDCA reduced serum Zn, and PBA reduced hepatic Cu to normal levels in the diabetic mice at two time points, while PBA normalized serum Cu in the diabetic mice only at 2 months. PBA increased hepatic Zn to normal levels in the diabetic mice at 2 weeks, while it partially increased hepatic Zn in the same group at 2 months. Therefore, maintaining homeostasis of Cu and Zn by TUDCA and PBA in diabetes needs to be received with special attention.

Substitutes for Bear Bile for the Treatment of Liver Diseases: Research Progress and Future Perspective

Bear bile has been a well-known Chinese medicine for thousands of years. Because of the endangered species protection, the concept on substitutes for bear bile was proposed decades ago. Based on their chemical composition and pharmacologic actions, artificial bear bile, bile from other animals, synthetic compounds, and medicinal plants may be the promising candidates to replace bear bile for the similar therapeutic purpose. Accumulating research evidence has indicated that these potential substitutes for bear bile have displayed the same therapeutic effects as bear bile. However, stopping the use of bear bile is a challenging task. In this review, we extensively searched PubMed and CNKI for literatures, focusing on comparative studies between bear bile and its substitutes for the treatment of liver diseases. Recent research progress in potential substitutes for bear bile in the last decade is summarized, and a strategy for the use of substitutes for bear bile is discussed carefully.

Effect of asymmetric dimethylarginine (ADMA) on heart failure development

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthases that limits nitric oxide bioavailability and can increase production of NOS derived reactive oxidative species. Increased plasma ADMA is a one of the strongest predictors of mortality in patients who have had a myocardial infarction or suffer from chronic left heart failure, and is also an independent risk factor for several other conditions that contribute to heart failure development, including hypertension, coronary artery disease/atherosclerosis, diabetes, and renal dysfunction. The enzyme responsible for ADMA degradation is dimethylarginine dimethylaminohydrolase-1 (DDAH1). DDAH1 plays an important role in maintaining nitric oxide bioavailability and preserving cardiovascular function in the failing heart. Here, we examine mechanisms of abnormal NO production in heart failure, with particular focus on the role of ADMA and DDAH1.

Efficacy and Safety of "URSA Complex" in Subjects with Physical Fatigue: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial

BACKGROUND

Fatigue is a common symptom both in diseases status and in healthy subjects. Various supplements and nutraceuticals for relieving of fatigue have been used. However, there are a few studies to evaluate the efficacy and the safety of the drug for fatigue alleviation, we conducted using URSA Complex to evaluate the efficacy on physical fatigue via score changes in the checklist individual strength (CIS).

METHODS

The study was designed as a multicenter, randomized, double-blind, placebo-controlled trial, with subjects randomized to one of the two arms, receiving either placebo or URSA Complex administered as identical capsules. The primary efficacy endpoints of this clinical trials are the ratio of improving CIS scores < 76 points in patients at the end (4 weeks). Secondary efficacy variables are as follows one is an improvement of fatigue and the other is an improvement of the liver enzyme.

RESULTS

The fatigue recovery rate in who had improved CIS scores of < 76 points were 70.0%, 50.9% in the therapy group and placebo group, respectively (P = 0.019). The fatigue recovery rate in CIS score was higher in URSA Complex therapy group than placebo group. The difference between therapy group and placebo group was statistically significant at 4 weeks later, but not 2 weeks.

CONCLUSIONS

Our results provided that the URSA Complex was effective in alleviating physical fatigue. The adverse event frequency in the therapy groups was similar to that in the placebo group.

Combination therapy of fenofibrate and ursodeoxycholic acid in patients with primary biliary cirrhosis who respond incompletely to UDCA monotherapy: a meta-analysis

Background

Although the effectiveness of treatment with ursodeoxycholic acid (UDCA) and fenofibrate for primary biliary cirrhosis (PBC) has been suggested by small trials, a systematic review to summarize the evidence has not yet been carried out.

Methods

A meta-analysis of all long-term randomized controlled trials comparing the combination of UDCA and fenofibrate with UDCA monotherapy was performed via electronic searches.

Results

Six trials, which included 84 patients, were assessed. Combination therapy with UDCA and fenofibrate was more effective than UDCA monotherapy in improving alkaline phosphatase (mean difference [MD]: −90.44 IU/L; 95% confidence interval [CI]: −119.95 to −60.92; P<0.00001), gamma-glutamyl transferase (MD: −61.58 IU/L; 95% CI: −122.80 to −0.35; P=0.05), immunoglobulin M (MD: −38.45 mg/dL; 95% CI: −64.38 to −12.51; P=0.004), and triglycerides (MD: −0.41 mg/dL; 95% CI: −0.82 to −0.01; P=0.05). However, their effects on pruritus (odds ratio [OR]: 0.39; 95% CI: 0.09–1.78; P=0.23), total bilirubin (MD: −0.05 mg/dL; 95% CI: −0.21 to 0.12; P=0.58), and alanine aminotransferase (MD: −3.31 IU/L; 95% CI: −14.60 to 7.97; P=0.56) did not differ significantly. This meta-analysis revealed no significant differences in the incidence of adverse events (OR: 0.21; 95% CI: 0.03–1.25; P=0.09) between patients treated with combination therapy and those treated with monotherapy.

Conclusion

In this meta-analysis, combination therapy with UDCA and fenofibrate was more effective in reducing alkaline phosphatase than UDCA monotherapy, but it did not improve clinical symptoms. There did not appear to be an increase in adverse events with combination therapy.

Colitis-associated neoplasia: molecular basis and clinical translation

Crohn's disease and ulcerative colitis are both associated with an increased risk of inflammation-associated colorectal carcinoma. Colitis-associated cancer (CAC) is one of the most important causes for morbidity and mortality in patients with inflammatory bowel diseases (IBD). Colitis-associated neoplasia distinctly differs from sporadic colorectal cancer in its biology and the underlying mechanisms. This review discusses the molecular mechanisms of CAC and summarizes the most important genetic alterations and signaling pathways involved in inflammatory carcinogenesis. Then, clinical translation is evaluated by discussing new endoscopic techniques and their contribution to surveillance and early detection of CAC. Last, we briefly address different types of concepts for prevention (i.e., anti-inflammatory therapeutics) and treatment (i.e., surgical intervention) of CAC and give an outlook on this important aspect of IBD.

Ursodeoxycholic acid improves bilirubin but not albumin in primary biliary cirrhosis: further evidence for nonefficacy

Background/Aim. In randomised controlled trials (RCTs) of ursodeoxycholic acid (UDCA), although serum bilirubin is frequently reduced, its effect on disease progression and mortality is unclear. As serum albumin is an established independent prognostic marker, one might expect less deterioration of serum albumin values in a UDCA-treated group. We therefore modelled the typical evolution of serum bilirubin and albumin levels over time in UDCA-untreated patients and compared it with the observed levels in UDCA RCTs. Methods. Multilevel modelling was used to relate the evolution of serum albumin to serum bilirubin and time since patient referral. For each considered RCT, the derived model was used to predict the relationship between final mean serum albumin and bilirubin concentration, adjusted for mean serum albumin at referral and followup duration. Results. Five RCTs were eligible in terms of available data, of which two had long followup. In all trials, serum albumin did not significantly differ between UDCA- and placebo-treated patients, despite the UDCA effect on serum bilirubin. Therefore, there is no evidence over time for changes or maintenance of albumin levels for UDCA-treated patients above the levels predicted for placebo-treated patients. Conclusions. Our findings suggest that UDCA does not alter serum albumin in a way that is consistent with its effect on serum bilirubin. Therefore, reductions in serum bilirubin of UDCA-treated PBC do not parallel another validated and independent prognostic marker, further questioning the validity of serum bilirubin reduction with UDCA as a surrogate therapeutic marker.

Regulation of DDAH1 as a Potential Therapeutic Target for Treating Cardiovascular Diseases

Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor that blocks nitric oxide production, while congestive heart failure is associated with increased plasma and tissue ADMA content. Increased plasma ADMA is a strong and independent predictor of all-cause mortality in the community and the strongest predictor of mortality in patients after myocardial infarction. Recent studies demonstrated that dimethylarginine dimethylaminohydrolase-1 (DDAH1) is the critical enzyme for ADMA degradation and thereby plays an important role in maintaining cardiovascular nitric oxide bioavailability. Interestingly, activation of the farnesoid X receptor (FXR) through the bile acid ursodeoxycholic acid (UDCA) or synthetic FXR agonists, such as GW4064, can increase DDAH1 expression. Thus, modulating DDAH1 activity through FXR receptor agonists such as UDCA could be a therapeutic target for treating reduced nitric oxide bioavailability in congestive heart failure and other cardiovascular diseases.

Tauroursodeoxycholic acid mitigates high fat diet-induced cardiomyocyte contractile and intracellular Ca2+ anomalies

OBJECTIVES

The endoplasmic reticulum (ER) chaperone tauroursodeoxycholic acid (TUDCA) has exhibited promises in the treatment of obesity, although its impact on obesity-induced cardiac dysfunction is unknown. This study examined the effect of TUDCA on cardiomyocyte function in high-fat diet-induced obesity.

METHODS

Adult mice were fed low or high fat diet for 5 months prior to treatment of TUDCA (300 mg/kg. i.p., for 15d). Intraperitoneal glucose tolerance test (IPGTT), cardiomyocyte mechanical and intracellular Ca(2+) property, insulin signaling molecules including IRS-1, Akt, AMPK, ACC, GSK-3β, c-Jun, ERK and c-Jun N terminal kinase (JNK) as well as ER stress and intracellular Ca(2+) regulatory proteins were examined. Myocardial ultrastructure was evaluated using transmission electron microscopy (TEM).

RESULTS

High-fat diet depressed peak shortening (PS) and maximal velocity of shortening/relengthenin as well as prolonged relengthening duration. TUDCA reversed or overtly ameliorated high fat diet-induced cardiomyocyte dysfunction including prolongation in relengthening. TUDCA alleviated high-fat diet-induced decrease in SERCA2a and phosphorylation of phospholamban, increase in ER stress (GRP78/BiP, CHOP, phosphorylation of PERK, IRE1α and eIF2α), ultrastructural changes and mitochondrial permeation pore opening. High-fat diet feeding inhibited phosphorylation of AMPK and promoted phosphorylation of GSK-3β. TUDCA prevented high fat-induced dephosphorylation of AMPK but not GSK-3β. High fat diet promoted phosphorylation of IRS-1 (Ser(307)), JNK, and ERK without affecting c-Jun phosphorylation, the effect of which with the exception of ERK phosphorylation was attenuated by TUDCA.

CONCLUSIONS

These data depict that TUDCA may ameliorate high fat diet feeding-induced cardiomyocyte contractile and intracellular Ca(2+) defects through mechanisms associated with mitochondrial integrity, AMPK, JNK and IRS-1 serine phosphorylation.

Endoplasmic reticulum chaperon tauroursodeoxycholic acid alleviates obesity-induced myocardial contractile dysfunction

ER stress is involved in the pathophysiology of obesity although little is known about the role of ER stress on obesity-associated cardiac dysfunction. This study was designed to examine the effect of ER chaperone tauroursodeoxycholic acid (TUDCA) on obesity-induced myocardial dysfunction. Adult lean and ob/ob obese mice were treated with TUDCA (50mg/kg/day, p.o.) or vehicle for 5 weeks. Oral glucose tolerance test (OGTT) was performed. Echocardiography, cardiomyocyte contractile and intracellular Ca(2+) properties were assessed. Sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) activity and protein expression of intracellular Ca(2+) regulatory proteins were measured using (45)Ca(2+) uptake and Western blot analysis, respectively. Insulin signaling, ER stress markers and HSP90 were evaluated. Our results revealed that chronic TUDCA treatment lowered systolic blood pressure and lessened glucose intolerance in obese mice. Obesity led to increased diastolic diameter, cardiac hypertrophy, compromised fractional shortening, cardiomyocyte contractile (peak shortening, maximal velocity of shortening/relengthening, and duration of contraction/relaxation) and intracellular Ca(2+) properties, all of which were significantly attenuated by TUDCA. TUDCA reconciled obesity-associated decrease in SERCA activity and expression, and increase in serine phosphorylation of IRS, total and phosphorylated cJun, ER stress markers Bip, peIF2α and pPERK. Obesity-induced changes in phospholamban and HSP90 were unaffected by TUDCA. In vitro finding revealed that TUDCA ablated palmitic acid-induced cardiomyocyte contractile dysfunction. In summary, these data depicted a pivotal role of ER stress in obesity-associated cardiac contractile dysfunction, suggesting the therapeutic potential of ER stress as a target in the management of cardiac dysfunction in obesity.

Tauroursodeoxycholic acid attenuates lipid accumulation in endoplasmic reticulum-stressed macrophages

BACKGROUND/AIM

Recent evidence suggests that endoplasmic reticulum (ER) stress provoked under diabetic conditions augments the expression of scavenger receptors on macrophages, promoting the uptake of oxidized low-density lipoprotein uptake and atherogenesis. The aim of the present study was to test the hypothesis that the chemical chaperone tauroursodeoxycholic acid (TUDCA) attenuates lipid accumulation in macrophages subjected to ER stress.

METHODS

Cultured human macrophages were subjected to ER stress by treating them with tunicamycin. Lipid uptake by macrophages subjected to ER stress in the presence or absence of TUDCA was assessed by oil red O staining and by assessing the cellular uptake of Dil-oxidized low-density lipoprotein by fluorescence measurement. Protein levels and phosphorylation status of ER stress markers, insulin-signaling molecules, and scavenger receptor were assessed by Western blotting.

RESULTS

Treatment of cultured human macrophages with the ER stressor tunicamycin caused an increase in the protein levels of cluster of differentiation 36 (CD-36) and augmentation of lipid uptake both of which were inhibited by TUDCA. TUDCA treatment inhibited tunicamycin-induced ER stress as evidenced by the attenuation of phosphorylation of eukaryotic translation initiation factor-2a and glucose reactive protein-78. In addition, TUDCA improved insulin signaling in macrophages by augmenting Akt phosphorylation and blunting c-Jun N-terminal kinase activity.

CONCLUSIONS

Inhibition of macrophage ER stress may represent a potential strategy in preventing atherogenesis under diabetic conditions.

Bile acids in treatment of ocular disease

Bear bile has been included in Asian pharmacopeias for thousands of years in treatment of several diseases, ranging from sore throat to hemorrhoids. The hydrophilic bile acids tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) are the major bile acids of bear bile. Both of these are available as synthetic formulations and are approved by the health administrations of several countries for treatment of cirrhosis and gallstones. This review briefly covers the use of bear bile in Traditional Chinese Medicine, bile acid physiology, approved use of UDCA and TUDCA in Western medicine, and recent research exploring their neuroprotective properties, including in models of ocular disease.