CDCS-TCM: A framework based on complex network theory to analyze the causality and dynamic correlation of substances in the metabolic process of traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine, with the feature of synergistic effects of multi-component, multi-pathway and multi-target, plays an important role in the treatment of cancer, cardiovascular and cerebrovascular diseases, etc. However, chemical components in traditional Chinese medicine are complex and most of the pharmacological mechanisms remain unclear, especially the relationships of chemical components change during the metabolic process.

AIM OF STUDY

Our aim is to provide a method based on complex network theory to analyze the causality and dynamic correlation of substances in the metabolic process of traditional Chinese medicine.

MATERIALS AND METHODS

We proposed a framework named CDCS-TCM to analyze the causality and dynamic correlation between substances in the metabolic process of traditional Chinese medicine. Our method mainly consists two parts. The first part is to discover the local and global causality by the causality network. The second part is to investigate the dynamic correlations and identify the essential substance by dynamic substance correlation network.

RESULTS

We developed a CDCS-TCM method to analyze the causality and dynamic correlation of substances. Using the XiangDan Injection for ischemic stroke as an example, we have identified the important substances in the metabolic process including substance pairs with strong causality and the dynamic changes of the core effector substance clusters.

CONCLUSION

The proposed framework will be useful for exploring the correlations of active ingredients in traditional Chinese medicine more effectively and will provide a new perspective for the elucidation of drug action mechanisms and the new drug discovery.

Increased hepatoprotective effects of the novel farnesoid X receptor agonist INT-787 versus obeticholic acid in a mouse model of nonalcoholic steatohepatitis

The nuclear farnesoid X receptor (FXR), a master regulator of bile acid and metabolic homeostasis, is a key target for treatment of nonalcoholic steatohepatitis (NASH). This study compared efficacy of FXR agonists obeticholic acid (OCA) and INT-787 by liver histopathology, plasma biomarkers of liver damage, and hepatic gene expression profiles in the Amylin liver NASH (AMLN) diet-induced and biopsy-confirmed Lepob/ob mouse model of NASH. Lepob/ob mice were fed the AMLN diet for 12 weeks before liver biopsy and subsequent treatment with vehicle, OCA, or INT-787 for 8 weeks. Hepatic steatosis, inflammation, and fibrosis (liver lipids, galectin-3, and collagen 1a1 [Col1a1], respectively), as well as plasma alanine transaminase (ALT) and aspartate transaminase (AST) levels, were assessed. Hepatic gene expression was assessed in Lepob/ob mice that were fed the AMLN diet for 14 weeks then treated with vehicle, OCA, or INT-787 for 2 weeks. INT-787, which is equipotent to OCA but more hydrophilic, significantly reduced liver lipids, galectin-3, and Col1a1 compared with vehicle, and to a greater extent than OCA. INT-787 significantly reduced plasma ALT and AST levels, whereas OCA did not. INT-787 modulated a substantially greater number of genes associated with FXR signaling, lipid metabolism, and stellate cell activation relative to OCA in hepatic tissue. These findings demonstrate greater efficacy of INT-787 treatment compared with OCA in improving liver histopathology, decreasing liver enzyme levels, and enhancing gene regulation, suggesting superior clinical potential of INT-787 for the treatment of NASH and other chronic liver diseases.

Safety, pharmacokinetics and pharmacodynamics of obeticholic acid in subjects with fibrosis or cirrhosis from NASH

BACKGROUND & AIMS

Fibrosis stage is a strong predictor of nonalcoholic steatohepatitis (NASH) outcomes. Two blinded studies evaluated the pharmacokinetics, pharmacodynamics and safety of obeticholic acid (OCA) in subjects with staged NASH fibrosis or cirrhosis.

METHODS

Study 747-117 randomized 51 subjects with NASH (fibrosis stages F1-F4) to daily placebo, OCA 10 or OCA 25 mg (1:2:2) for 85 days. Study 747-118 randomized 24 subjects with NASH cirrhosis (F4; Child-Pugh [CP]-A) and normal liver control subjects matched for similar body weight to daily OCA 10 or OCA 25 mg (1:1) for 28 days. Individual and combined study data were analysed.

RESULTS

No severe or serious adverse events (AEs) or AEs leading to discontinuation or death occurred. Pruritus was the most frequent AE. Plasma OCA exposure (dose-normalized area under the curve) increased with fibrosis stage but was a relatively poor predictor of hepatic OCA exposure (primary site of action), which remained constant across fibrosis stages F1-F3 and increased 1.8-fold compared with F1 in subjects with cirrhosis due to NASH. Both cohorts showed robust changes in farnesoid X receptor activation markers with OCA treatment and marked decreases in alanine transaminase, aspartate transaminase and gamma-glutamyltransferase.

CONCLUSIONS

Despite higher drug exposures in subjects with NASH cirrhosis, short-term daily treatment with OCA 10 or 25 mg was generally safe and well tolerated in subjects with NASH fibrosis or NASH CP-A cirrhosis. Both cohorts experienced improvements in nonhistologic pharmacodynamic markers consistent with previously conducted OCA phase 2 and phase 3 studies in NASH fibrosis.

Hepatic-Accumulated Obeticholic Acid and Atorvastatin Self-Assembled Nanocrystals Potentiate Ameliorative Effects in Treatment of Metabolic-Associated Fatty Liver Disease

Exploration of medicines for efficient and safe management of metabolic-associated fatty liver disease (MAFLD) remains a challenge. Obeticholic acid (OCA), a selective farnesoid X receptor agonist, has been reported to ameliorate injury and inflammation in various liver diseases. However, its clinical application is mainly limited by poor solubility, low bioavailability, and potential side effects. Herein a hepatic-targeted nanodrugs composed of OCA and cholesterol-lowering atorvastatin (AHT) with an ideal active pharmaceutical ingredient (API) content for orally combined treatment of MAFLD is created. Such carrier-free nanocrystals (OCAHTs) are self-assembled, not only improving the stability in gastroenteric environments but also achieving hepatic accumulation through the bile acid transporter-mediated enterohepatic recycling process. Orally administrated OCAHT outperforms the simple combination of OCA and AHT in ameliorating of liver damage and inflammation in both acetaminophen-challenged mice and high-fat diet-induced MAFLD mice with less systematic toxicity. Importantly, OCAHT exerts profoundly reverse effects on MAFLD-associated molecular pathways, including impairing lipid metabolism, reducing inflammation, and enhancing the antioxidation response. This work not only provides a facile bile acid transporter-based strategy for hepatic-targeting drug delivery but also presents an efficient and safe full-API nanocrystal with which to facilitate the practical translation of nanomedicines against MAFLD.

The effect and safety of obeticholic acid for patients with nonalcoholic steatohepatitis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH) is one of the primary causes of chronic liver disease worldwide. Obeticholic acid (OCA), a potent farnesoid X nuclear receptor activator, has shown promise for treating NASH-related fibrosis due to its anti-fibrotic effects. This study aimed to examine the efficacy of OCA for patients with NASH as well as to investigate its impact on dyslipidemia.

METHOD

A search of databases including PubMed, Embase, and Cochrane Library from January 1, 2010, to November 1, 2022, was conducted to identify systematic reviews of randomized controlled trials involving NASH patients. Inclusion criteria comprised randomized controlled trials that specifically addressed NASH as diagnosed through magnetic resonance imaging, computed tomography, or histology. The results were then categorized, with consideration given to both biochemical and histological outcomes.

RESULT

Five NASH studies were ultimately selected for further analysis. In terms of biochemical indicators, patients receiving OCA treatment showed improvements in alanine transaminase (mean difference: -19.48, 95% confidence interval [CI]: -24.39 to 14.58; P < .05) and aspartate aminotransferase (mean difference: -9.22, 95% CI: -12.70 to 5.74; P < .05). As for histological improvement, OCA treatment reduced fibrosis (odds ratio [OR]: 1.95, 95% CI: 1.47-2.59; P = .001) and steatosis (OR: 1.95, 95% CI: 1.47-2.59; P = .001). No significant differences were observed regarding adverse events (1.44, 95% CI: 0.57-3.62; P > .001). Regarding dyslipidemia, mean differences between total cholesterol and low-density lipoprotein were found to be high (0.33, 95% CI: 0.01-0.64, P < .05; 0.39, 95% CI: 0.04-0.73, P < .05). In the case of pruritus, OCA achieved a high OR (3.22, 95% CI: 2.22-4.74) compared with placebo.

CONCLUSION

OCA also reduced several liver test markers compared to placebo, including the biochemical indicators alanine transaminase, aspartate aminotransferase, alkaline phosphatase, and γ-glutamyl transpeptidase, and improved hepatocellular ballooning, fibrosis, steatosis, and lobular inflammation. Although the incidence of adverse events did not significantly differ between OCA and placebo groups among NASH patients, OCA treatment was found to elevate total cholesterol and low-density lipoprotein levels, and the reported severity of pruritus increased with higher doses of OCA.

The obeticholic acid can positively regulate the cancerous behavior of MCF7 breast cancer cell line

BACKGROUND

The diagnosis and treatment processes of cancer are among the main challenges of medical science in recent decades. The use of different therapeutic agents is one of the most common methods frequently utilized for cancer treatment. Accumulating evidence points to a potential effect of Obeticholic acid (OCA), a specific ligand for farnesoid X receptor, on the regulation of cancer-associated pathways. In spite of tremendous efforts to introduce OCA into the clinical setting, there is a great deal of uncertainty about its impact on breast cancer treatment. This study was performed to evaluate the effects of OCA on breast cancer.

METHODS AND RESULTS

In this experiment, the MCF-7 (Michigan Cancer Foundation-7) cell line was treated with 0.1 µM OCA, and cancerous characteristics of the MCF-7 cell line was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide) assay, gelatin zymography, western blot, Real-time PCR, flow cytometry, and ELISA techniques. The results indicated that OCA increased the rate of apoptosis and the expression levels of PPARα (Peroxisome proliferator-activated receptor alpha) and TIMP-1 (tissue inhibitor of metalloproteinase-1) genes in this cell line, while it reduced the mRNA levels of MMP7 (matrix metalloproteinase 7) and Bcl-2 (B-cell lymphoma 2) genes, as well as the protein levels of the active form of AKT (protein kinase B), Erk1/2 (extracellular signal-regulated kinase 1/2) and STAT3 (Signal transducers and activators of transcription-3). Also, OCA decreased the activity of MMP9, while it increased the secretion of VEGF-A (vascular endothelial growth factor-A).

CONCLUSIONS

It seems that OCA can exert anti-cancer effects on the MCF-7 cells by reducing growth, proliferation, migration, invasion, and regulation of the expression of genes involved in cancer-associated pathways. However, it should be noted that further studies are warranted to establish this concept, especially the increase of VEGF-A can be considered a challenge for the results of this study.

Measuring the experience of social connection within specific social interactions: The Connection During Conversations Scale (CDCS)

Decades of research have demonstrated that social connection is fundamental to health and well-being. The benefits of connection are observed with both close and distant others, within both new and established relationships, and even with exchanges that unfold over a relatively short timeframe. Because social connection is fundamental to well-being, many existing measures in the literature aim to assess either a global sense of connection or partner-specific (relationship-specific) connection. What is missing are measures of connection felt in specific social interactions or conversations. In three studies (Study 1: N = 351; Study 2: Time 1 N = 397, Time 2 N = 336, Time 3 N = 299; Study 3: N = 235), we developed the Connection During Conversations Scale (CDCS), a 14-item measure of conversation-specific social connection that assesses connection experienced during a social interaction (or conversation). Confirmatory factor analyses demonstrated that a four-factor model fit our samples well, which resulted in four subscales: Shared Reality, Partner Responsiveness, Participant Interest, and Affective Experience. The overall CDCS measure, along with its four subscales, was significantly correlated with established measures of loneliness, partner responsiveness, relatedness, positivity resonance, and shared reality. Because of the importance of frequent interactions-whether with family, friends, coworkers, or strangers-our new scale will allow researchers to better understand how, when, and where such conversations may contribute to social connection and well-being. (225 words).

Suppression of Lung Oxidative Stress, Inflammation, and Fibrosis following Nitrogen Mustard Exposure by the Selective Farnesoid X Receptor Agonist Obeticholic Acid

Nitrogen mustard (NM) is a cytotoxic vesicant known to cause pulmonary injury that can progress to fibrosis. NM toxicity is associated with an influx of inflammatory macrophages in the lung. Farnesoid X receptor (FXR) is a nuclear receptor involved in bile acid and lipid homeostasis that has anti-inflammatory activity. In these studies, we analyzed the effects of FXR activation on lung injury, oxidative stress, and fibrosis induced by NM. Male Wistar rats were exposed to phosphate-buffered saline (vehicle control) or NM (0.125 mg/kg) by intratracheal Penncentury-MicroSprayer aerosolization; this was followed by treatment with the FXR synthetic agonist, obeticholic acid (OCA, 15 mg/kg), or vehicle control (0.13-0.18 g peanut butter) 2 hours later and then once per day, 5 days per week thereafter for 28 days. NM caused histopathological changes in the lung, including epithelial thickening, alveolar circularization, and pulmonary edema. Picrosirius red staining and lung hydroxyproline content were increased, indicative of fibrosis; foamy lipid-laden macrophages were also identified in the lung. This was associated with aberrations in pulmonary function, including increases in resistance and hysteresis. Following NM exposure, lung expression of HO-1 and iNOS, and the ratio of nitrates/nitrites in bronchoalveolar lavage fluid (BAL), markers of oxidative stress increased, along with BAL levels of inflammatory proteins, fibrinogen, and sRAGE. Administration of OCA attenuated NM-induced histopathology, oxidative stress, inflammation, and altered lung function. These findings demonstrate that FXR plays a role in limiting NM-induced lung injury and chronic disease, suggesting that activating FXR may represent an effective approach to limiting NM-induced toxicity. SIGNIFICANCE STATEMENT: In this study, the role of farnesoid-X-receptor (FXR) in mustard vesicant-induced pulmonary toxicity was analyzed using nitrogen mustard (NM) as a model. This study's findings that administration of obeticholic acid, an FXR agonist, to rats reduces NM-induced pulmonary injury, oxidative stress, and fibrosis provide novel mechanistic insights into vesicant toxicity, which may be useful in the development of efficacious therapeutics.

A Short Review on Obeticholic Acid: An Effective Modulator of Farnesoid X Receptor

Farnesoid X receptor (FXR) was identified as an orphan nuclear receptor resembling the steroid receptor in the late '90s. Activation of FXR is a crucial step in many physiological functions of the liver. A vital role of FXR is impacting the amount of bile acids in the hepatocytes, which it performs by reducing bile acid synthesis, stimulating the bile salt export pump, and inhibiting its enterohepatic circulation, thus protecting the hepatocytes against the toxic accumulation of bile acids. Furthermore, FXR mediates bile acid biotransformation in the intestine, liver regeneration, glucose hemostasis, and lipid metabolism. In this review, we first discuss the mechanisms of the disparate pleiotropic actions of FXR agonists. We then delve into the pharmacokinetics of Obeticholic acid (OCA), the first-in-class selective, potent FXR agonist. We additionally discuss the clinical journey of OCA in humans, its current evidence in various human diseases, and its plausible roles in the future.

Farnesoid X receptor (FXR) agonists induce hepatocellular apoptosis and impair hepatic functions via FXR/SHP pathway

Farnesoid X receptor (FXR) plays an indispensable role in liver homeostasis and has been a promising drug target for hepatic diseases. However, the concerns of undesired biological actions limit the clinical applications of FXR agonists. To reveal the intrinsic mechanism of FXR agonist-induce hepatotoxicity, two typical FXR agonists with different structures (obeticholic acid (OCA) and Px-102) were investigated in the present study. By detecting MMP, ROS, and ATP and analyzing the fate of cells, we found that both OCA and Px-102 reduced the mitochondrial function of hepatocytes and promoted cell apoptosis. Gene ablation or inhibition of FXR or SHP ameliorated the cytotoxicities of OCA and Px-102, which indicated the adverse actions of FXR/SHP activation including down-regulation of phosphorylation of PI3K/AKT and functional hepatic genes. The dose-related injurious effects of OCA (10 mg/kg and 30 mg/kg) and Px-102 (5 mg/kg and 15 mg/kg) on the liver were confirmed on a high-fat diet mouse model. The decrease of hepatocyte-specific genes and augmenter of liver regeneration in the liver caused by OCA or Px-102 suggested an imbalance of liver regeneration and a disruption of hepatic functions. Exploration of intestinally biased FXR agonists or combination of FXR agonist with apoptosis inhibitor may be more beneficial strategies for liver diseases.

Discovery of new and highly effective quadruple FFA1 and PPARα/γ/δ agonists as potential anti-fatty liver agents

Non-alcoholic fatty liver disease (NAFLD) has become the most common hepatic disease, while no drug was approved until now. The previous study reported that the quadruple FFA1/PPAR-α/γ/δ agonist RLA8 provided better efficacy than obeticholic acid on NASH. In the present study, two design strategies were introduced to explore better quadruple FFA1/PPAR-α/γ/δ agonists with improved metabolic stability. These efforts ultimately resulted in the identification of ZLY18, a quadruple FFA1/PPAR-α/γ/δ agonist with twice higher metabolic half-life than RLA8 in the liver microsome. In the triton-1339W-induced hyperlipidemic model, ZLY18 reversed hyperlipidemia to an almost normal level, which exhibited far stronger lipid-lowering effects than that of RLA8. Moreover, ZLY18 significantly decreased steatosis, hepatocellular ballooning, inflammation and liver fibrosis in NASH model even better than RLA8. Further mechanism studies suggested that ZLY18 exerts stronger effects than RLA8 on the regulation of the gene related to lipid synthesis, oxidative stress, inflammation and fibrosis. In addition, ZLY18 is more effective than pirfenidone in the prevention of CCl4-induced liver fibrosis. Besides, ZLY18 has an acceptable safety profile in the acute toxicity study at a high dose of 500 mg/kg. Therefore, ZLY18 represents a novel and highly promising quadruple FFA1/PPAR-α/γ/δ agonist worth of further investigation and development.

Protection of ischemic white matter and oligodendrocytes in mice by 3K3A-activated protein C

Subcortical white matter (WM) stroke accounts for 25% of all strokes and is the second leading cause of dementia. Despite such clinical importance, we still do not have an effective treatment for ischemic WM stroke, and the mechanisms of WM postischemic neuroprotection remain elusive. 3K3A-activated protein C (APC) is a signaling-selective analogue of endogenous blood protease APC that is currently in development as a neuroprotectant for ischemic stroke patients. Here, we show that 3K3A-APC protects WM tracts and oligodendrocytes from ischemic injury in the corpus callosum in middle-aged mice by activating protease-activated receptor 1 (PAR1) and PAR3. We show that PAR1 and PAR3 were also required for 3K3A-APC's suppression of post-WM stroke microglia and astrocyte responses and overall improvement in neuropathologic and functional outcomes. Our data provide new insights into the neuroprotective APC pathway in the WM and illustrate 3K3A-APC's potential for treating WM stroke in humans, possibly including multiple WM strokes that result in vascular dementia.

Development and in vitro Profiling of Dual FXR/LTA4H Modulators

Designed polypharmacology presents as an attractive strategy to increase therapeutic efficacy in multi-factorial diseases by a directed modulation of multiple involved targets with a single molecule. Such an approach appears particularly suitable in non-alcoholic steatohepatitis (NASH) which involves hepatic steatosis, inflammation and fibrosis as pathological hallmarks. Among various potential pharmacodynamic mechanisms, activation of the farnesoid X receptor (FXRa) and inhibition of leukotriene A4 hydrolase (LTA4Hi) hold promise to counteract NASH according to preclinical and clinical observations. We have developed dual FXR/LTA4H modulators as pharmacological tools, enabling evaluation of this polypharmacology concept to treat NASH and related pathologies. The optimized FXRa/LTA4Hi exhibits well-balanced dual activity on the intended targets with sub-micromolar potency and is highly selective over related nuclear receptors and enzymes rendering it suitable as tool to probe synergies of dual FXR/LTA4H targeting.

A Sensitive HPLC-MS/MS Method for Determination of Obeticholic Acid in Human Plasma: Application to a Pharmacokinetic Study in Healthy Volunteers

A rapid and sensitive LC-MS/MS method was developed and fully validated for the determination of obeticholic acid in human plasma. Glimepiride was used as internal standard. For this method, liquid-liquid extraction was performed to extract analyte from the plasma samples. Chromatographic separation was performed on a C18 (2.1 × 50 mm, 2.7 μm, Agilent) column with isocratic elution using water containing 0.1% formic acid and acetonitrile containing 0.1% formic acid at a flow rate of 0.4 mL/min. The mass detection was performed in negative mode. The precursor-product ion pairs for MRM were m/z 465.3 → 419.3 for obeticholic acid and m/z 489.3 → 224.8 for the IS. The method exhibited great linearity over the concentration range of 0.150-100 ng/mL for obeticholic acid. The sensitivity, linearity, accuracy, precision, recovery, matrix effect and stability of this method were all within the acceptable limits. The method was successfully validated and applied to the pharmacokinetic studies in healthy Chinese volunteers after a single oral dose administration of obeticholic acid tablets of 10 mg, and the pharmacokinetic characteristics of obeticholic acid in human were reported for the first time.

A new mechanism of obeticholic acid on NASH treatment by inhibiting NLRP3 inflammasome activation in macrophage

OBJECTIVE

Obeticholic acid (OCA) has been proved to play potential therapeutic effect on nonalcoholic steatohepatitis (NASH). Up to now, the study of OCA on NLRP3 inflammasome activation in macrophage is still blank and merits great attention. Here, we aimed to better characterize the role and mechanism of OCA on NASH treatment focusing on NLRP3 inflammasome activation in macrophages.

METHODS

The effects of OCA on inflammasome activation were investigated in BMDM, Kupffer cell, BMDC and LX2 cell. Preconditioned media from BMDM culture was used to treat primary hepatocytes to explore the effects of macrophage NLRP3 inflammasome activation on the function of hepatocytes. In vivo, high fat diet plus CCl₄ (DIO + CCl₄) induced murine NASH model and choline-deficient and amino acid-defined (CDA) diet-induced NASH mice were used to verify the inhibitory effect of OCA on inflammasome activation in liver macrophages and recapitulate its protective role on NASH progressing. To clear up the effect of OCA on macrophage is FXR dependent or not, FXR siRNA was introduced into BMDMs.

RESULTS

OCA blockaded NLRP3 inflammasome in BMDMs by impacting on the activation stage and disrupting ASC oligomerization. Preconditioned supernatant from LPS + ATP treated BMDMs increased mRNA expression of lipogenic enzymes and lipid content, whereas preconditioned supernatant from OCA treated BMDM blocked these effects in both normal and the FXR knockdown hepatocytes. In DIO + CCl₄ mice, the population of inflammatory myeloid lineage cells in livers was decreased upon OCA treatment. Accordingly, the level of IL-1β and IL-18 in liver, the hepatic expression of ASC, pro-caspase-1 and active caspase-1, the expression of caspase 1 p20 in liver macrophages were also reduced. Similar results were obtained in CDA diet-fed mice. Furthermore, OCA maintained the inhibition on NLRP3 inflammasome activation in FXR knockdown BMDMs, suggesting FXR could be dispensable in this effect.

CONCLUSIONS

This finding brings up a new mechanism of OCA on NASH treatment, suggested by direct inhibition on NLRP3 inflammasome activation in macrophage, further suppression on inflammasome activation-elicited hepatic lipid accumulation, and contributing to the amelioration of NASH.

Potential of therapeutic bile acids in the treatment of neonatal Hyperbilirubinemia

Neonatal hyperbilirubinemia or jaundice is associated with kernicterus, resulting in permanent neurological damage or even death. Conventional phototherapy does not prevent hyperbilirubinemia or eliminate the need for exchange transfusion. Here we investigated the potential of therapeutic bile acids ursodeoxycholic acid (UDCA) and obeticholic acid (OCA, 6-α-ethyl-CDCA), a farnesoid-X-receptor (FXR) agonist, as preventive treatment options for neonatal hyperbilirubinemia using the hUGT1*1 humanized mice and Ugt1a-deficient Gunn rats. Treatment of hUGT1*1 mice with UDCA or OCA at postnatal days 10-14 effectively decreased bilirubin in plasma (by 82% and 62%) and brain (by 72% and 69%), respectively. Mechanistically, our findings indicate that these effects are mediated through induction of protein levels of hUGT1A1 in the intestine, but not in liver. We further demonstrate that in Ugt1a-deficient Gunn rats, UDCA but not OCA significantly decreases plasma bilirubin, indicating that at least some of the hypobilirubinemic effects of UDCA are independent of UGT1A1. Finally, using the synthetic, non-bile acid, FXR-agonist GW4064, we show that some of these effects are mediated through direct or indirect activation of FXR. Together, our study shows that therapeutic bile acids UDCA and OCA effectively reduce both plasma and brain bilirubin, highlighting their potential in the treatment of neonatal hyperbilirubinemia.

Obeticholic Acid Derivative, T-2054 Suppresses Osteoarthritis via Inhibiting NF-κB-Signaling Pathway

Osteoarthritis (OA), a degenerative joint disorder, has been reported as the most common cause of disability worldwide. The production of inflammatory cytokines is the main factor in OA. Previous studies have been reported that obeticholic acid (OCA) and OCA derivatives inhibited the release of proinflammatory cytokines in acute liver failure, but they have not been studied in the progression of OA. In our study, we screened our small synthetic library of OCA derivatives and found T-2054 had anti-inflammatory properties. Meanwhile, the proliferation of RAW 264.7 cells and ATDC5 cells were not affected by T-2054. T-2054 treatment significantly relieved the release of NO, as well as mRNA and protein expression levels of inflammatory cytokines (IL-6, IL-8 and TNF-α) in LPS-induced RAW 264.7 cells. Moreover, T-2054 promoted extracellular matrix (ECM) synthesis in TNF-α-treated ATDC5 chondrocytes. Moreover, T-2054 could relieve the infiltration of inflammatory cells and degeneration of the cartilage matrix and decrease the levels of serum IL-6, IL-8 and TNF-α in DMM-induced C57BL/6 mice models. At the same time, T-2054 showed no obvious toxicity to mice. Mechanistically, T-2054 decreased the extent of p-p65 expression in LPS-induced RAW 264.7 cells and TNF-α-treated ATDC5 chondrocytes. In summary, we showed for the first time that T-2054 effectively reduced the release of inflammatory mediators, as well as promoted extracellular matrix (ECM) synthesis via the NF-κB-signaling pathway. Our findings support the potential use of T-2054 as an effective therapeutic agent for the treatment of OA.

The efficacy of novel metabolic targeted agents and natural plant drugs for nonalcoholic fatty liver disease treatment: A PRISMA-compliant network meta-analysis of randomized controlled trials

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent chronic liver disease characterized by excess accumulation of fat in hepatocytes. Because no drug has been approved for NAFLD treatment, this work analyzed the effects of agents resulting from 2 research hotspots, metabolic target agents, and natural plant drugs, on NAFLD with network meta-analysis.

METHODS

Public databases were searched through August 14, 2020. Randomized controlled trials that compared obeticholic acid, elafibranor, cenicriviroc, selonsertib, curcumin, silymarin, and resveratrol to placebo were included. Liver pathology improvement, hepatic biochemical indicators, and lipid metabolism indicators were analyzed.

RESULTS

Thirty-five studies were included in the meta-analysis. Obeticholic acid was found to significantly increase the frequency of liver biopsy improvement compared to placebo (OR: 2.10; 95% CI: 1.60, 2.77). The ranking results among the hepatic biochemical indicators showed that obeticholic acid (94.9%) and elafibranor (86.3%) have a relative advantage in reducing alanine aminotransferase (ALT) levels, and obeticholic acid also had an advantage (95.4%) in reducing aspartate aminotransferase (AST) levels. Considering lipid metabolic indicators, elafibranor (expSMD: 0.01; 95% CI: 0.00, 0.05; SUCRA: 100%), and obeticholic acid (expSMD: 0.48; 95% CI: 0.28,0.84; SUCRA: 75.6%) significantly reduced triglyceride (TG) levels compared with placebo; moreover, obeticholic acid, but not elafibranor, caused a serious increase in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels and a decrease in high-density lipoprotein cholesterol (HDL-C) levels.

CONCLUSIONS

Novel metabolic targeted agents generally have better effects than natural plant drugs, especially obeticholic acid, and elafibranor. However, obeticholic acid showed serious adverse effects such as increasing LDL-C levels and decreasing HDL-C levels. Curcumin showed potential advantages for NAFLD but lacked statistical significance.

Unaltered Liver Regeneration in Post-Cholestatic Rats Treated with the FXR Agonist Obeticholic Acid

In a previous study, obeticholic acid (OCA) increased liver growth before partial hepatectomy (PHx) in rats through the bile acid receptor farnesoid X-receptor (FXR). In that model, OCA was administered during obstructive cholestasis. However, patients normally undergo PHx several days after biliary drainage. The effects of OCA on liver regeneration were therefore studied in post-cholestatic Wistar rats. Rats underwent sham surgery or reversible bile duct ligation (rBDL), which was relieved after 7 days. PHx was performed one day after restoration of bile flow. Rats received 10 mg/kg OCA per day or were fed vehicle from restoration of bile flow until sacrifice 5 days after PHx. Liver regeneration was comparable between cholestatic and non-cholestatic livers in PHx-subjected rats, which paralleled liver regeneration a human validation cohort. OCA treatment induced ileal Fgf15 mRNA expression but did not enhance post-PHx hepatocyte proliferation through FXR/SHP signaling. OCA treatment neither increased mitosis rates nor recovery of liver weight after PHx but accelerated liver regrowth in rats that had not been subjected to rBDL. OCA did not increase biliary injury. Conclusively, OCA does not induce liver regeneration in post-cholestatic rats and does not exacerbate biliary damage that results from cholestasis. This study challenges the previously reported beneficial effects of OCA in liver regeneration in cholestatic rats.

Primary biliary cholangitis

Primary biliary cholangitis is an autoimmune liver disease that predominantly affects women. It is characterised by a chronic and destructive, small bile duct, granulomatous lymphocytic cholangitis, with typical seroreactivity for antimitochondrial antibodies. Patients have variable risks of progressive ductopenia, cholestasis, and biliary fibrosis. Considerations for the cause of this disease emphasise an interaction of chronic immune damage with biliary epithelial cell responses and encompass complex, poorly understood genetic risks and environmental triggers. Licensed disease-modifying treatment focuses on amelioration of cholestasis, with weight-dosed oral ursodeoxycholic acid. For patients who do not respond sufficiently, or patients with ursodeoxycholic acid intolerance, conditionally licensed add-on therapy is with the FXR (NR1H4) agonist, obeticholic acid. Off-label therapy is recognised as an alternative, notably with the pan-PPAR agonist bezafibrate; clinical trial agents are also under development. Baseline characteristics, such as young age, male sex, and advanced disease, and serum markers of liver injury, particularly bilirubin and ALP, are used to stratify risk and assess treatment responsiveness. Parallel attention to the burden of patient symptoms is paramount, including pruritus and fatigue.

Obeticholic acid reduces biliary and hepatic matrix metalloproteinases activity in rat hepatic ischemia/reperfusion injury

Background

We have previously shown that obeticholic acid (OCA) upregulates the biliary excretion of asymmetric dimethylarginine (ADMA), an inhibitor of iNOS regulating the activity of matrix metalloproteinases (MMPs). Here, the effects of OCA on MMP-2 and MMP-9 activity in liver, bile and serum were evaluated after hepatic ischemia/reperfusion (I/R) injury.

Material and methods

Male Wistar rats (n = 20) were orally administered 10 mg/kg/day of OCA (5 days) and subjected to a 60-min ischemia and 60-min reperfusion. Bile, serum and tissue were collected for MMP-2 and MMP-9 activity quantification. The MMP regulator tissue reversion-inducing cysteine rich protein with Kazal motifs (RECK), tissue inhibitor of metalloproteinases (TIMPs), iNOS and biliary levels of LDH, γGT, glucose and ADMA were quantified.

Results

In the I/R group, OCA administration reduced MMP-2 and MMP-9 in liver, bile and serum. A downregulation of tissue RECK and TIMPs, observed under I/R, were recovered by OCA. Immunohistochemical staining of hepatic tissue demonstrated that RECK expression is mainly localized in both cholangiocytes and hepatocytes. Hepatic iNOS positively correlated with tissue MMP-2 and MMP-9 activity. Biliary levels of LDH, γGT and glucose were lower in I/R rats treated with OCA; in bile, MMP levels positively correlated with LDH and γGT.

Conclusion

Thus, OCA administration confers protection to cholangiocytes via downregulation of biliary MMPs in livers submitted to I/R. This event is associated with hepatic RECK- and TIMP-mediated MMP decrease.

3β-Isoobeticholic acid efficiently activates the farnesoid X receptor (FXR) due to its epimerization to 3α-epimer by hepatic metabolism

Bile acids (BAs) are important signaling molecules acting via the farnesoid X nuclear receptor (FXR) and the membrane G protein-coupled bile acid receptor 1 (GPBAR1). Besides deconjugation of BAs, the oxidoreductive enzymes of colonic bacteria and hepatocytes enable the conversion of BAs into their epimers or dehydrogenated forms. Obeticholic acid (OCA) is the first-in-class BA-derived FXR agonist approved for the treatment of primary biliary cholangitis. Herein, a library of OCA derivatives, including 7-keto, 6-ethylidene derivatives and 3β-epimers, was synthetized and investigated in terms of interactions with FXR and GPBAR1 in transaction assays and evaluated for FXR target genes expression in human hepatocytes and C57BL/6 mice. The derivatives were further subjected to cell-free analysis employing in silico molecular docking and a TR-FRET assay. The conversion of the 3βhydroxy epimer and its pharmacokinetics in mice were studied using LC-MS. We found that only the 3β-hydroxy epimer of OCA (3β-isoOCA) possesses significant activity to FXR in hepatic cells and mice. However, in a cell-free assay, 3β-isoOCA had about 9-times lower affinity to FXR than did OCA. We observed that 3β-isoOCA readily epimerizes to OCA in hepatocytes and murine liver. This conversion was significantly inhibited by the hydroxy-Δ⁵-steroid dehydrogenase inhibitor trilostane. In addition, we found that 3,7-dehydroobeticholic acid is a potent GPBAR1 agonist. We conclude that 3β-isoOCA significantly activates FXR due to its epimerization to the more active OCA by hepatic metabolism. Other modifications as well as epimerization on the C3/C7 positions and the introduction of 6-ethylidene in the CDCA scaffold abrogate FXR agonism and alleviate GPBAR1 activation.

Effective treatment of autoimmune hepatitis-primary biliary cholangitis overlap syndrome with obeticholic acid

There is no consensus treatment for patients with autoimmune hepatitis (AIH) - primary biliary cholangitis (PBC) overlap syndrome who are not responding to conventional therapy. We present a case of a 43-yr-old woman with AIH-PBC overlap syndrome treated with obeticholic acid (OCA). The patient showed a reduction in liver enzymes and no fibrosis progression during 15 months of follow up.

Facial synthesis of key intermediate of obeticholic acid via Pd-catalyzed Kumada-Tamao-Corriu cross-coupling reaction

Obeticholic acid (OCA) is used to treatment for Primary Biliary Cholangitis and other Famesoid X Receptor related diseases. Through the palladium catalyzed Kumada-Tamao-Corriu cross-coupling reaction, a novel and efficient method for synthesis of OCA with satisfied yield was successfully developed. The absolute configuration of the key intermediate was confirmed by Single-crystal X-ray Diffraction. It affords good strategy for large-scale synthesis of OCA.

Diagnosis and treatment of primary biliary cholangitis

Primary biliary cholangitis is a cholestatic, chronic autoimmune liver disease with a wide individual variation in disease progression. The diagnosis is predominantly based on chronic elevation of alkaline phosphatase and the presence of anti-mitochondrial antibodies or other specific antinuclear antibodies (i.e. anti-gp210 and anti-sp100). Even in early-stage disease, health-related quality of life can be severely impaired by symptoms such as pruritus, fatigue, and sicca syndrome and metabolic bone disease should be assessed and treated. The prognosis of the disease is, however, largely determined by the development of cirrhosis and its complications. Ursodeoxycholic acid is associated with an improved prognosis and should be initiated and continued in all patients. Clinical outcome is related to the biochemical response to ursodeoxycholic acid, but the prognosis of those with an incomplete response is still better than those who remain untreated. Obeticholic acid was recently approved as second-line treatment and bezafibrate may serve as an adequate off-label alternative, particularly in patients with pruritus. Preliminary data suggest an additive effect of triple therapy with ursodeoxycholic acid, obeticholic acid, and bezafibrate, whereas other promising drugs are being evaluated in clinical trials.

Opposite effects of the FXR agonist obeticholic acid on Mafg and Nrf2 mediate the development of acute liver injury in rodent models of cholestasis

The farnesoid-X-receptor (FXR) is validated target in the cholestatic disorders treatment. Obeticholic acid (OCA), the first in class of FXR agonist approved for clinical use, causes side effects including acute liver decompensation when administered to cirrhotic patients with primary biliary cholangitis at higher than recommended doses. The V-Maf avian-musculoaponeurotic-fibrosarcoma-oncogene-homolog-G (Mafg) and nuclear factor-erythroid-2-related-factor-2 (Nrf2) mediates some of the downstream effects of FXR. In the present study we have investigated the role of FXR/MafG/NRF2 pathway in the development of liver toxicity caused by OCA in rodent models of cholestasis. Cholestasis was induced by bile duct ligation (BDL) or administration of α-naphtyl-isothiocyanate (ANIT) to male Wistar rats and FXR^-/- and FXR^+/+ mice. Treating BDL and ANIT rats with OCA exacerbated the severity of cholestasis, hepatocytes injury and severely downregulated the expression of basolateral transporters. In mice, genetic ablation FXR or its pharmacological inhibition by 3-(naphthalen-2-yl)-5-(piperidin-4-yl)-1,2,4-oxadiazole rescued from negative regulation of MRP4 and protected against liver injury caused by ANIT. By RNAseq analysis we found that FXR antagonism effectively reversed the transcription of over 2100 genes modulated by OCA/ANIT treatment, including Mafg and Nrf2 and their target genes Cyp7a1, Cyp8b1, Mat1a, Mat2a, Gss. Genetic and pharmacological Mafg inhibition by liver delivery of siRNA antisense or S-adenosylmethionine effectively rescued from damage caused by ANIT/OCA. In contrast, Nrf2 induction by sulforaphane was protective. CONCLUSIONS: Liver injury caused by FXR agonism in cholestasis is FXR-dependent and is reversed by FXR and Mafg antagonism or Nrf2 induction.

FXR activation promotes intestinal cholesterol excretion and attenuates hyperlipidemia in SR-B1-deficient mice fed a high-fat and high-cholesterol diet

Obeticholic acid (OCA) activates the farnesoid X receptor (FXR) to lower circulating total cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) concentrations and to stimulate fecal cholesterol excretion in mice by increasing hepatic SR-B1 expression. Here we show that hepatic SR-B1 depletion by an adenovirus expressing Sr-b1 shRNA (Ad-shSR-B1) attenuated these beneficial effects of OCA in mice on a chow diet. The mRNA levels of ABC cholesterol transporter genes (Abca1, Abcg1, Abcg5, and Abcg8) were unchanged in the liver of hepatic SR-B1-depleted mice regardless of OCA treatment; however, a modest increase in Abca1, Abcg5, and Abcg8 mRNA levels was observed in the ileum of vehicle-treated control mice and Abca1 and Abcg8 mRNA levels were increased more by OCA administration. OCA treatment of Sr-b1 knock out (KO) mice (Sr-b1-/-) fed a normal chow diet (NCD) displayed a similar lack of transhepatic cholesterol movement, as well as a modest increase in the levels of ileum cholesterol transporter expression. However, OCA treatment of Sr-b1 KO mice fed a cholesterol-enriched diet reduced circulating cholesterol and increased fecal cholesterol output to comparable degrees to that of wild-type (WT) mice, and these effects were accompanied by substantial elevations of mRNA levels of Abca1, Abcg1, Abcg5, and Abcg8 in the ileum of Sr-b1 KO mice. Our studies suggest that FXR activation stimulates intestinal cholesterol excretion and reduces diet-induced hyperlipidemia through increased expression of ileal cholesterol transporters when hepatic SR-B1-mediated cholesterol movement is absent.

Obeticholic acid for the treatment of non-alcoholic steatohepatitis: interim analysis from a multicentre, randomised, placebo-controlled phase 3 trial

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a common type of chronic liver disease that can lead to cirrhosis. Obeticholic acid, a farnesoid X receptor agonist, has been shown to improve the histological features of NASH. Here we report results from a planned interim analysis of an ongoing, phase 3 study of obeticholic acid for NASH.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled study, adult patients with definite NASH, non-alcoholic fatty liver disease (NAFLD) activity score of at least 4, and fibrosis stages F2-F3, or F1 with at least one accompanying comorbidity, were randomly assigned using an interactive web response system in a 1:1:1 ratio to receive oral placebo, obeticholic acid 10 mg, or obeticholic acid 25 mg daily. Patients were excluded if cirrhosis, other chronic liver disease, elevated alcohol consumption, or confounding conditions were present. The primary endpoints for the month-18 interim analysis were fibrosis improvement (≥1 stage) with no worsening of NASH, or NASH resolution with no worsening of fibrosis, with the study considered successful if either primary endpoint was met. Primary analyses were done by intention to treat, in patients with fibrosis stage F2-F3 who received at least one dose of treatment and reached, or would have reached, the month 18 visit by the prespecified interim analysis cutoff date. The study also evaluated other histological and biochemical markers of NASH and fibrosis, and safety. This study is ongoing, and registered with ClinicalTrials.gov, NCT02548351, and EudraCT, 20150-025601-6.

FINDINGS

Between Dec 9, 2015, and Oct 26, 2018, 1968 patients with stage F1-F3 fibrosis were enrolled and received at least one dose of study treatment; 931 patients with stage F2-F3 fibrosis were included in the primary analysis (311 in the placebo group, 312 in the obeticholic acid 10 mg group, and 308 in the obeticholic acid 25 mg group). The fibrosis improvement endpoint was achieved by 37 (12%) patients in the placebo group, 55 (18%) in the obeticholic acid 10 mg group (p=0·045), and 71 (23%) in the obeticholic acid 25 mg group (p=0·0002). The NASH resolution endpoint was not met (25 [8%] patients in the placebo group, 35 [11%] in the obeticholic acid 10 mg group [p=0·18], and 36 [12%] in the obeticholic acid 25 mg group [p=0·13]). In the safety population (1968 patients with fibrosis stages F1-F3), the most common adverse event was pruritus (123 [19%] in the placebo group, 183 [28%] in the obeticholic acid 10 mg group, and 336 [51%] in the obeticholic acid 25 mg group); incidence was generally mild to moderate in severity. The overall safety profile was similar to that in previous studies, and incidence of serious adverse events was similar across treatment groups (75 [11%] patients in the placebo group, 72 [11%] in the obeticholic acid 10 mg group, and 93 [14%] in the obeticholic acid 25 mg group).

INTERPRETATION

Obeticholic acid 25 mg significantly improved fibrosis and key components of NASH disease activity among patients with NASH. The results from this planned interim analysis show clinically significant histological improvement that is reasonably likely to predict clinical benefit. This study is ongoing to assess clinical outcomes.

FUNDING

Intercept Pharmaceuticals.

Position statement on the diagnosis and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a major national and international health burden. It is one of the most common liver diseases worldwide and the most common cause of abnormal liver enzymes in many developed countries. Non-alcoholic fatty liver disease is also known as an important cause of cryptogenic cirrhosis and second leading cause for liver transplantation. It is commonly associated with metabolic syndrome. Non-alcoholic steatohepatitis (NASH) is the progressive phenotype of NAFLD. In spite of promising performance of non-invasive tools, liver biopsy remains the gold standard test for NASH diagnosis. Over decades, many drugs have been investigated in phase 2 and 3; however, no approved therapy to date. Despite the alarming global rates of NAFLD, there are no local community-based studies on the prevalence of NAFLD or local practice guidelines on its management; this expert review aims to fill this gap.

Magnetic-Assisted Treatment of Liver Fibrosis

Chronic liver injury can be induced by viruses, toxins, cellular activation, and metabolic dysregulation and can lead to liver fibrosis. Hepatic fibrosis still remains a major burden on the global health systems. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are considered the main cause of liver fibrosis. Hepatic stellate cells are key targets in antifibrotic treatment, but selective engagement of these cells is an unresolved issue. Current strategies for antifibrotic drugs, which are at the critical stage 3 clinical trials, target metabolic regulation, immune cell activation, and cell death. Here, we report on the critical factors for liver fibrosis, and on prospective novel drugs, which might soon enter the market. Apart from the current clinical trials, novel perspectives for anti-fibrotic treatment may arise from magnetic particles and controlled magnetic forces in various different fields. Magnetic-assisted techniques can, for instance, enable cell engineering and cell therapy to fight cancer, might enable to control the shape or orientation of single cells or tissues mechanically. Furthermore, magnetic forces may improve localized drug delivery mediated by magnetism-induced conformational changes, and they may also enhance non-invasive imaging applications.

REGENERATE: Design of a pivotal, randomised, phase 3 study evaluating the safety and efficacy of obeticholic acid in patients with fibrosis due to nonalcoholic steatohepatitis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a chronic, progressive, and severe form of nonalcoholic fatty liver disease. In FLINT, obeticholic acid (OCA) treatment improved multiple histological NASH features. The design and endpoints of REGENERATE, an ongoing phase 3 study, further evaluate OCA treatment in patients with fibrosis due to NASH.

AIMS

The Month 18 interim analysis assesses the effect of OCA on liver histology, defined as improvement of fibrosis by ≥1 stage with no worsening of NASH or resolution of NASH with no worsening of fibrosis. The end-of-study analyses evaluate the effect of OCA on mortality, liver-related clinical outcomes, and long-term safety.

METHODS

REGENERATE is a pivotal, long-term study of ~2400 patients with NASH, including ~2100 patients with stage 2 or 3 liver fibrosis. Additionally, ~300 patients with stage 1 fibrosis and ≥1 accompanying comorbidity are included to gather information on the safety of OCA and liver disease progression. Patients are randomised 1:1:1 to receive placebo or OCA (10 or 25 mg). A liver biopsy evaluation occurs at screening, Months 18 and 48, and end of study. The duration of the study is dependent upon accrual of a predetermined number of clinical outcome events.

CONCLUSIONS

REGENERATE is designed in conjunction with regulatory authorities to support regulatory approvals in NASH. This robust phase 3 study assesses the effect of OCA on liver histology as a surrogate for transplant-free survival and liver-related outcomes, including progression to cirrhosis and mortality, and will ultimately assess clinical benefit through specific evaluation of these outcomes.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov with the identifier NCT02548351.

Therapeutic effects of the selective farnesoid X receptor agonist obeticholic acid in a monocrotaline-induced pulmonary hypertension rat model

BACKGROUND

Activation of the farnesoid X receptor (FXR), a member of the nuclear receptor steroid superfamily, leads to anti-inflammatory and anti-fibrotic effects in several tissues, including the lung. We have recently demonstrated a protective effect of the farnesoid X receptor (FXR) agonist obeticholic acid (OCA) in rat models of monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) and bleomycin-induced pulmonary fibrosis. The aim of the present study was to investigate whether the positive effects of OCA treatment could be exerted also in established MCT-induced PAH, i.e., starting treatment 2 weeks after MCT administration.

METHODS

Rats with MCT-induced PAH were treated, 2 weeks after MCT administration, with OCA or tadalafil for two additional weeks. Pulmonary functional tests were performed at week 2 (before treatment) and four (end of treatment). At the same time points, lung morphological features and expression profile of genes related to smooth muscle relaxation/contraction and tissue remodeling were also assessed.

RESULTS

2 weeks after MCT-induced injury, the treadmill resistance (a functional parameter related to pulmonary hypertension) was significantly decreased. At the same time point, we observed right ventricular hypertrophy and vascular remodeling, with upregulation of genes related to inflammation. At week 4, we observed a further worsening of the functional and morphological parameters, accompanied by dysregulation of inflammatory and extracellular matrix markers mRNA expression. Administration of OCA (3 or 10 mg/kg/day), starting 2 weeks after MCT-induced injury, significantly improved pulmonary function, effectively normalizing the exercise capacity. OCA also reverted most of the lung alterations, with a significant reduction of lung vascular wall thickness, right ventricular hypertrophy, and restoration of the local balance between relaxant and contractile pathways. Markers of remodeling pathways were also normalized by OCA treatment. Notably, results with OCA treatment were similar, or even superior, to those obtained with tadalafil, a recently approved treatment for pulmonary hypertension.

CONCLUSIONS

The results of this study demonstrate a significant therapeutic effect of OCA in established MCT-induced PAH, improving exercise capacity associated with reduction of right ventricular hypertrophy and lung vascular remodeling. Thus, OCA dosing in a therapeutic protocol restores the balance between relaxant and contractile pathways in the lung, promoting cardiopulmonary protective actions in MCT-induced PAH.

Obeticholic acid ameliorates dyslipidemia but not glucose tolerance in mouse model of gestational diabetes

Metabolism alters markedly with advancing gestation, characterized by progressive insulin resistance, dyslipidemia, and raised serum bile acids. The nuclear receptor farnesoid X receptor (FXR) has an integral role in bile acid homeostasis and modulates glucose and lipid metabolism. FXR is known to be functionally suppressed in pregnancy. The FXR agonist, obeticholic acid (OCA), improves insulin sensitivity in patients with type 2 diabetes with nonalcoholic fatty liver disease. We therefore hypothesized that OCA treatment during pregnancy could improve disease severity in a mouse model of gestational diabetes mellitus (GDM). C57BL/6J mice were fed a high-fat diet (HFD; 60% kcal from fat) for 4 wk before and throughout pregnancy to induce GDM. The impact of the diet supplemented with 0.03% OCA throughout pregnancy was studied. Pregnant HFD-fed mice displayed insulin resistance and dyslipidemia. OCA significantly reduced plasma cholesterol concentrations in nonpregnant and pregnant HFD-fed mice (by 22.4%, P < 0.05 and 36.4%, P < 0.001, respectively) and reduced the impact of pregnancy on insulin resistance but did not change glucose tolerance. In nonpregnant HFD-fed mice, OCA ameliorated weight gain, reduced mRNA expression of inflammatory markers in white adipose tissue, and reduced plasma glucagon-like peptide 1 concentrations (by 62.7%, P < 0.01). However, these effects were not evident in pregnant mice. OCA administration can normalize plasma cholesterol levels in a mouse model of GDM. However, the absence of several of the effects of OCA in pregnant mice indicates that the agonistic action of OCA is not sufficient to overcome many metabolic consequences of the pregnancy-associated reduction in FXR activity.

Metabolism of obeticholic acid in brown bullhead (Ameiurus nebulosus)

Analysis of brown bullhead (Ameiurus nebulosus) bile by ultra performance liquid chromatography high-resolution mass spectrometry (UPLC/HRMS) revealed a series of bile acids similar to those found in humans. Accordingly, we chose this fish as a model organism to examine the metabolism of obeticholic acid, a bile acid used to treat a number of human liver diseases and the one that has the potential to occur as an environmental contaminant. The taurine and glycine conjugates of obeticholic acid and keto-obeticholic acid were identified, as well as the D-cysteinolic acid conjugate of obeticholic acid, likely a metabolite specific to fish. In addition, metabolites of obeticholic acid (sulphate and glucuronide) and several hydroxy-obeticholic acid derivatives were found, representing typical pathways of primary and secondary steroid metabolism. Brown bullhead exposed to obeticholic acid at a dose of 100 mg/kg gave no overt signs of distress or toxicity.

Therapeutic effects of obeticholic acid (OCA) treatment in a bleomycin-induced pulmonary fibrosis rat model

PURPOSE

We recently demonstrated a protective effect of the farnesoid X receptor agonist obeticholic acid (OCA) in rat models of bleomycin-induced pulmonary fibrosis (PF). Aim of the present study was to investigate whether the positive effects of OCA treatment are apparent also on ongoing bleomycin-induced PF, i.e., after 2 weeks of bleomycin administration.

METHODS

Bleomycin-induced PF rats were treated 2 weeks after bleomycin administration with OCA or pirfenidone for two additional weeks. Pulmonary function test was performed at 2 and 4 weeks in all experimental groups. At the same time points, lung morphological features and mRNA expression profile of genes related to fibrosis, inflammation and epithelial-mesenchymal transition were also assessed.

RESULTS

After 2 weeks, bleomycin significantly increased the pressure at the airway opening (PAO), a functional parameter related to fibrosis-induced lung stiffness, and induced diffuse lung interstitium fibrosis, with upregulation of inflammation (IL1β, MCP1) and tissue remodeling (COL1A1, COL3A1, ET1, MMP7, PDGFa, αSMA, SNAI1) markers. At week four, a further increase of lung fibrosis and PAO was observed, accompanied by upregulation of extracellular matrix-related mRNA expression. OCA administration, even after the establishment of PF, significantly improved pulmonary function, normalizing PAO, and reverted the bleomycin-induced lung alterations, with significant reduction of markers of inflammation (CD206, COX2, HIF1, IL1β, MCP1), epithelial proliferation (CTGF, PDGFa) and fibrosis (COL1A1, COL3A1, ET1, FN1, MMPs, αSMA, SNAIs, TGFβ1, TIMPs). Results with OCA were similar or superior to those obtained with pirfenidone.

CONCLUSIONS

In conclusion, our results demonstrate a significant therapeutic effect of OCA in already established PF.

Obeticholic acid differentially regulates hepatic injury and inflammation at different stages of D-galactosamine/lipopolysaccharide-evoked acute liver failure

The farnesoid X receptor (FXR) is a ligand-activated transcription factor that regulates genes involved in bile acid metabolism. Accumulating data demonstrate that FXR has an anti-inflammatory activity. The present study aimed to investigate the effect of obeticholic acid (OCA), a novel synthetic FXR agonist, on D-galactosamine (GalN)/lipopolysaccharide (LPS)-evoked acute liver injury. All mice except controls were intraperitoneally injected with GalN (300 mg/kg) plus LPS (2.5 μg/kg). Some mice were pretreated with OCA (10 mg/kg) 48, 24 and 1 h before GalN/LPS. As expected, pretreatment with OCA alleviated hepatocyte apoptosis at early and middle stages of GalN/LPS-induced acute liver failure. By contrast, pretreatment with OCA augmented hepatic injury and inflammatory cell infiltration at middle stage of GalN/LPS-induced acute liver failure. Additional experiment found that OCA inhibited hepatic NF-κB activation at early and middle stages of GalN/LPS-induced acute liver failure. Interestingly, OCA inhibited hepatic proinflammatory cytokine tnf-α and il-6 but upregulated hepatic anti-inflammatory cytokine il-10 at early stage of GalN/LPS-induced acute liver failure. By contrast, OCA suppressed hepatic anti-inflammatory cytokine tgf-β and il-10 at middle stage of GalN/LPS-induced acute liver injury. These results suggest that FXR agonist OCA differentially regulates hepatic injury and inflammation at different stages of GalN/LPS-evoked acute liver failure.

Obeticholic Acid: An Update of Its Pharmacological Activities in Liver Disorders

Obeticholic acid (OCA), 6α-ethyl-3α,7α-dihydroxy-5-cholan-24-oic acid, is a semisynthetic derivative of the chenodeoxycholic acid (CDCA, 3α,7α-dihydroxy-5-cholan-24-oic acid), a relatively hydrophobic primary bile acid synthesized in the liver from cholesterol. OCA, also known as 6-ethyl-CDCA or INT-747, was originally described by investigators at the Perugia University in 2002 as a selective ligand for the bile acid sensor, farnesoid-X-receptor (FXR). In addition to FXR and similarly to CDCA, OCA also activates GPBAR1/TGR5, a cell membrane G protein-coupled receptor for secondary bile acids. In 2016, based on the results of phase II studies showing efficacy in reducing the plasma levels of alkaline phosphatase, a surrogate biomarker for disease progression in primary biliary cholangitis (PBC), OCA has gained approval as a second-line treatment for PBC patients nonresponsive to UDCA. The use of OCA in PBC patients associates with several side effects, the most common of which is pruritus, whose incidence is dose-dependent and is extremely high when this agent is used as a monotherapy. Additionally, the use of OCA associates with the increased risk for the development of liver failure in cirrhotic PBC patients. Currently, OCA is investigated for its potential in the treatment of nonalcoholic steatohepatitis (NASH). Phase II and III trials have shown that OCA might attenuate the severity of liver fibrosis in patients with NASH, but it has no efficacy in reversing the steatotic component of the disease, while reduces the circulating levels of HDL-C and increases LDL-C. In summary, OCA has been the first-in-class of FXR ligands advanced to a clinical stage and is now entering its third decade of life, highlighting the potential benefits and risk linked to FXR-targeted therapies.

Nonsteroidal FXR Ligands: Current Status and Clinical Applications

FXR agonists have demonstrated very promising clinical results in the treatment of liver disorders such as primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and nonalcoholic steatohepatitis (NASH). NASH, in particular, is one of the last uncharted white territories in the pharma landscape, and there is a huge medical need and a large potential pharmaceutical market for a NASH pharmacotherapy. Clinical efficacy superior to most other treatment options was shown by FXR agonists such as obeticholic acid (OCA) as they improved various metabolic features including liver steatosis as well as liver inflammation and fibrosis. But OCA's clinical success comes with some major liabilities such as pruritus, high-density lipoprotein cholesterol (HDL_c) lowering, low-density lipoprotein cholesterol (LDL_c) increase, and a potential for drug-induced liver toxicity. Some of these effects can be attributed to on-target effects exerted by FXR, but with others it is not clear whether it is FXR- or OCA-related. Therefore a quest for novel, proprietary FXR agonists is ongoing with the aim to increase FXR potency and selectivity over other proteins and to overcome at least some of the OCA-associated clinical side effects through an improved pharmacology. In this chapter we will discuss the historical and ongoing efforts in the identification and development of nonsteroidal, which largely means non-bile acid-type, FXR agonists for clinical use.

A facile synthesis of ursodeoxycholic acid and obeticholic acid from cholic acid

A novel synthetic route of producing ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) was developed through multiple reactions from cheap and readily-available cholic acid. The reaction conditions of the key elimination reaction of mesylate ester group were also investigated and optimized, including solvent, base and reaction temperature. In the straightforward synthetic route for preparation of UDCA and OCA, most of the reaction steps have high conversions with average yields of 94% and 92%, and overall yield up to 65% (7 steps) and 36% (11 steps) from cholic acid, respectively. This promising route offers economical and efficient strategies for potential large-scale production of UDCA and OCA.

FXR agonist obeticholic acid induces liver growth but exacerbates biliary injury in rats with obstructive cholestasis

Cholestasis impairs liver regeneration following partial liver resection (PHx). Bile acid receptor farnesoid X-receptor (FXR) is a key mediator of liver regeneration. The effects of FXR agonist obeticholic acid (OCA) on liver (re)growth were therefore studied in cholestatic rats. Animals underwent sham surgery or reversible bile duct ligation (rBDL). PHx with concurrent internal biliary drainage was performed 7 days after rBDL. Animals were untreated or received OCA (10 mg/kg/day) per oral gavage from rBDL until sacrifice. After 7 days of OCA treatment, dry liver weight increased in the rBDL + OCA group, indicating OCA-mediated liver growth. Enhanced proliferation in the rBDL + OCA group prior to PHx concurred with a rise in Ki67-positive hepatocytes, elevated hepatic Ccnd1 and Cdc25b expression, and an induction of intestinal fibroblast growth factor 15 expression. Liver regrowth after PHx was initially stagnant in the rBDL + OCA group, possibly due to hepatomegaly prior to PHx. OCA increased hepatobiliary injury markers during BDL, which was accompanied by upregulation of the bile salt export pump. There were no differences in histological liver injury. In conclusion, OCA induces liver growth in cholestatic rats prior to PHx but exacerbates biliary injury during cholestasis, likely by forced pumping of bile acids into an obstructed biliary tree.

Nonalcoholic steatohepatitis, obesity, and cardiac dysfunction

PURPOSE OF REVIEW

Obesity and nonalcoholic steatohepatitis (NASH) are epidemiologically and pathophysiologically linked disorders. Here, we summarize the effect of obesity on NASH and how it has a cascading effect on cardiovascular dysfunction. We also review the current and emerging treatment options for NASH.

RECENT FINDINGS

The link between NASH and cardiac dysfunction has been further delineated in recent studies demonstrating endothelial dysfunction, diastolic dysfunction, and increased coronary artery calcification in patients with known NASH. Standard treatment of obesity with lifestyle interventions including diet, exercise, and behavioral modification has been shown to improve NASH as well as reduce cardiovascular dysfunction. In addition to FDA-approved drugs like vitamin E and pioglitazone, several agents including NGM282, obeticholic acid, elafibranor, and liraglutide are currently being investigated for their therapeutic potential in NASH. Recent studies show that bariatric surgery results in significant improvement or resolution of NASH.

SUMMARY

Obesity is a major factor in the development of nonalcoholic fatty liver disease (NAFLD) and its progression to steatohepatitis. Patients with NAFLD have a significant increase in cardiovascular disease risk. For biopsy-proven NASH, vitamin E and pioglitazone are the recommended medical treatments in addition to lifestyle modification.

The British Society of Gastroenterology/UK-PBC primary biliary cholangitis treatment and management guidelines

Primary biliary cholangitis (formerly known as primary biliary cirrhosis, PBC) is an autoimmune liver disease in which a cycle of immune mediated biliary epithelial cell injury, cholestasis and progressive fibrosis can culminate over time in an end-stage biliary cirrhosis. Both genetic and environmental influences are presumed relevant to disease initiation. PBC is most prevalent in women and those over the age of 50, but a spectrum of disease is recognised in adult patients globally; male sex, younger age at onset (<45) and advanced disease at presentation are baseline predictors of poorer outcome. As the disease is increasingly diagnosed through the combination of cholestatic serum liver tests and the presence of antimitochondrial antibodies, most presenting patients are not cirrhotic and the term cholangitis is more accurate. Disease course is frequently accompanied by symptoms that can be burdensome for patients, and management of patients with PBC must address, in a life-long manner, both disease progression and symptom burden. Licensed therapies include ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), alongside experimental new and re-purposed agents. Disease management focuses on initiation of UDCA for all patients and risk stratification based on baseline and on-treatment factors, including in particular the response to treatment. Those intolerant of treatment with UDCA or those with high-risk disease as evidenced by UDCA treatment failure (frequently reflected in trial and clinical practice as an alkaline phosphatase >1.67 × upper limit of normal and/or elevated bilirubin) should be considered for second-line therapy, of which OCA is the only currently licensed National Institute for Health and Care Excellence recommended agent. Follow-up of patients is life-long and must address treatment of the disease and management of associated symptoms.

Current Treatment Options for Primary Biliary Cholangitis

Primary biliary cholangitis is a progressive, autoimmune disease of the interlobular bile ducts, leading to secondary damage of hepatocytes that may progress to cirrhosis and liver failure. Until recently, the only approved treatment was ursodeoxycholic acid. However, 40% of patients do not have an adequate response. Obeticholic acid was approved for treatment as add-on therapy in this group of patients. Off-label use of fibrates has also been reported to be effective. Several new therapies are in development and may further add to the treatment options available to patients with primary biliary cholangitis.

[Treatment of non-alcoholic fatty liver disease]

Non-alcoholic fatty liver disease and especially non-alcoholic steatohepatitis (NASH) and fibrosis are associated with severe liver disease and increased cardiovascular risk. It is therefore important to identify patients with NASH fibrosis. Therapeutical options include life style intervention and pharmacological treatment with vitamin E and pioglitazone; however, evidence of effect is scarce for all options. New treatments are under investigation and include glucagon-like peptide-1, farnesoid receptor as well as peroxisome proliferator-activated receptor-α/δ agonists. Bariatric surgery may be an option in selected patients.

Obeticholic acid for severe bile acid diarrhea with intestinal failure: A case report and review of the literature

Bile acid diarrhea results from excessive amounts of bile acids entering the colon due to hepatic overexcretion of bile acids or bile acid malabsorption in the terminal ileum. The main therapies include bile acid sequestrants, such as colestyramine and colesevelam, which may be given in combination with the opioid receptor agonist loperamide. Some patients are refractory to conventional treatments. We report the use of the farnesoid X receptor agonist obeticholic acid in a patient with refractory bile acid diarrhea and subsequent intestinal failure. A 32-year-old woman with quiescent colonic Crohn’s disease and a normal terminal ileum had been diagnosed with severe bile acid malabsorption and complained of watery diarrhea and fatigue. The diarrhea resulted in hypokalemia and sodium depletion that made her dependent on twice weekly intravenous fluid and electrolyte infusions. Conventional therapies with colestyramine, colesevelam, and loperamide had no effect. Second-line antisecretory therapies with pantoprazole, liraglutide, and octreotide also failed. Third-line treatment with obeticholic acid reduced the number of stools from an average of 13 to an average of 7 per 24 h and improved the patient’s quality of life. The fluid and electrolyte balances normalized. The effect was sustained during follow-up for 6 mo with treatment at a daily dosage of 25 mg. The diarrhea worsened shortly after cessation of obeticholic acid. This case report supports the initial report that obeticholic acid may reduce bile acid production and improve symptoms in patients with bile acid diarrhea.

FXR activation by obeticholic acid or nonsteroidal agonists induces a human-like lipoprotein cholesterol change in mice with humanized chimeric liver

Obeticholic acid (OCA) is a selective farnesoid X receptor (FXR) agonist that regulates bile acid and lipid metabolism. FXR activation induces distinct changes in circulating cholesterol among animal models and humans. The mechanistic basis of these effects has been elusive because of difficulties in studying lipoprotein homeostasis in mice, which predominantly package circulating cholesterol in HDLs. Here, we tested the effects of OCA in chimeric mice whose livers are mostly composed (≥80%) of human hepatocytes. Chimeric mice exhibited a human-like ratio of serum LDL cholesterol (LDL-C) to HDL cholesterol (HDL-C) at baseline. OCA treatment in chimeric mice increased circulating LDL-C and decreased circulating HDL-C levels, demonstrating that these mice closely model the cholesterol effects of FXR activation in humans. Mechanistically, OCA treatment increased hepatic cholesterol in chimeric mice but not in control mice. This increase correlated with decreased SREBP-2 activity and target gene expression, including a significant reduction in LDL receptor protein. Cotreatment with atorvastatin reduced total cholesterol, rescued LDL receptor protein levels, and normalized serum LDL-C. Treatment with two clinically relevant nonsteroidal FXR agonists elicited similar lipoprotein and hepatic changes in chimeric mice, suggesting that the increase in circulating LDL-C is a class effect of FXR activation.