The effect of (-)-hydroxycitrate on the activity of the low-density-lipoprotein receptor and 3-hydroxy-3-methylglutaryl-CoA reductase levels in the human hepatoma cell line Hep G2

Photocatalytic Thio/Selenosulfonylation-Bicyclization of Indole-Tethered 1,6-Enynes Leading to Substituted Benzo[c]pyrrolo[1,2,3-lm]carbazoles

The photocatalyzed radical-triggered thio/selenosulfonylation-bicyclization of indole-tethered 1,6-enynes has been established for the first time, enabling the synthesis of various previously unreported thio/selenosulfonylated benzo[c]pyrrolo[1,2,3-lm]carbazoles with moderate to good yields under mild conditions. The reaction pathway was proposed, consisting of energy transfer, homolytic cleavage, radical addition, 5-exo-dig, radical coupling, and a Mallory reaction cascade. This approach exhibits a wide substrate compatibility and excellent tolerability toward various functional groups and is characterized by its remarkable efficiency in both bond formation and annulation.

Recent advance of ATP citrate lyase inhibitors for the treatment of cancer and related diseases

ATP citrate lyase (ACLY), a strategic metabolic enzyme that catalyzes the glycolytic to lipidic metabolism, has gained increasing attention as an attractive therapeutic target for hyperlipidemia, cancers and other human diseases. Despite of continual research efforts, targeting ACLY has been very challenging. In this field, most reported ACLY inhibitors are "substrate-like" analogues, which occupied with the same active pockets. Besides, some ACLY inhibitors have been disclosed through biochemical screening or high throughput virtual screening. In this review, we briefly summarized the cancer-related functions and the recent advance of ACLY inhibitors with a particular focus on the SAR studies and their modes of action. We hope to provide a timely and updated overview of ACLY and the discovery of new ACLY inhibitors.

Garcinia cambogia Extract Increased Hepatic Levels of Lipolysis-Stimulated Lipoprotein Receptor and Lipids in Mice on Normal Diet

Garcinia cambogia extract (GCE) is a popular weight-loss supplement that also lowers plasma triglyceride (TG) levels. We hypothesized that GCE-mediated inhibition of ATP citrate lyase and thereby hepatic TG production could lead to compensatory mechanisms, including increased hepatic TG uptake via lipoprotein receptors. GCE (20 mg/day) administered 40 days orally to female C57BL/6Rj mice on a standard chow diet led to a decrease in both plasma fasting and post-prandial TG-rich lipoprotein levels, but with no significant change in body weight gain. Lipolysis stimulated lipoprotein receptor (LSR) protein levels, but not those of LDL-receptor, were increased as compared to controls. Mouse Hepa1-6 cells treated with the GCE active ingredient, hydroxycitrate, also led to increased LSR protein levels. Hepatic total cholesterol, TG, and muscle TG contents were higher in GCE-treated animals as compared to controls, whereas adipose TG levels were unchanged. LSR and LDL-receptor protein levels were correlated with liver total cholesterol, but only LDL-receptor was associated with liver TG. These results show that GCE treatment in mice on a standard chow diet led to significantly increased liver and muscle lipids, with no significant change in adipose tissue TG levels, which should be considered in the long-term use of GCE.

Efficacy and safety of bempedoic acid lipid-lowering therapy: a systematic review and meta-analysis of randomized controlled trials

AIM

This systematic review and meta-analysis was conducted to synthesize the efficacy and safety of bempedoic acid in patients requiring lipid-lowering therapy.

METHODS

PubMed, Embase, and Scopus databases were searched for randomized controlled trials from inception till June 2023. The primary outcome was major adverse cardiovascular events (MACE), and secondary outcomes were all-cause mortality, serum lipid profile, and adverse events between bempedoic acid and comparators. ROB2 was used for risk of bias assessment. We pooled mean differences or relative risks (RR) along with 95% confidence intervals (random-effects model).

RESULTS

Five-hundred and thirty-one studies were screened and 17 (n = 21,131) were included for review. There was a significant reduction in the risk of MACE [RR, 0.88 (95% CI: 0.77 to 0.99), p = 0.03)] and all-cause mortality [RR, 0.90 (95% CI: 0.82 to 0.98), p = 0.02] following bempedoic acid treatment. Treatment with bempedoic acid led to a significant reduction in the mean serum total cholesterol [- 34.41 mg/dl (95% CI: - 42.43 to - 26.39), p < 0.001], low-density lipoprotein cholesterol (LDL-C) [- 33.91 mg/dl (95% CI: - 39.66 to - 28.17), p < 0.001], as well as high-density lipoprotein cholesterol (HDL-C) [- 2.40 mg/dl (95% CI: - 3.09 to - 1.71), p < 0.001] levels. However, there was a significant increase in the risk of hyperuricemia [RR, 2.05 (95% CI: 1.81 to 2.33), p < 0.001] following bempedoic acid treatment. The number needed to harm was large for all safety outcomes. The GRADE of evidence was moderate for all outcomes.

CONCLUSION

Bempedoic acid reduces the risk of MACE and all-cause mortality, lowers serum total cholesterol and LDL-C levels, and has a favorable safety profile. Trial registration ClinicalTrial.gov Identifier: CRD42023412837.

Phase 1, Single- and Multiple-Ascending-Dose, Food-Effect, and East Asian Subject Studies to Assess the Pharmacokinetics, Safety, and Tolerability of Bempedoic Acid, a Selective Inhibitor of Adenosine Triphosphate Citrate Lyase

Bempedoic acid is an adenosine triphosphate citrate lyase inhibitor that lowers low-density lipoprotein cholesterol by inhibiting cholesterol synthesis and upregulating hepatic low-density lipoprotein receptor expression. After oral dosing, bempedoic acid was readily absorbed, attaining maximum concentrations with a median time of 3.5 hours, and may be taken without regard to food. Steady-state oral pharmacokinetics in healthy adults receiving bempedoic acid at the approved 180 mg/day dose were characterized by mean maximum concentration of 20.6 µg/mL, area under the concentration-time curve over 24 hours of 289 µg·h/mL, and elimination half-life of 21.1 hours. Multiple-dose pharmacokinetics were linear at bempedoic acid doses of 120-220 mg/day. Circulating concentrations of the active metabolite ESP15228 were 18.0% of bempedoic acid concentrations on average. Comparisons of bempedoic acid 180 mg/day pharmacokinetics after single and multiple dosing revealed no clinically meaningful differences between Japanese, Chinese, and Western subjects. Mean estimates of bempedoic acid elimination half-life in Japanese (25.2 hours) and Chinese (20.0 hours) subjects were comparable to Western subjects (23.9 hours) following 14 days of once-daily dosing. Bempedoic acid was generally safe and well tolerated up to a dose of 220 mg/day across the study populations described herein.

Bempedoic acid for nonalcoholic fatty liver disease: evidence and mechanisms of action

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent progressive condition that lacks a specific pharmacological treatment. ATP-citrate lyase (ACLY) is one of the emergent targets for the treatment of NAFLD. This review aims to summarize the role of ACLY in NAFLD, provide evidences of the beneficial effects of the ACLY inhibitor bempedoic acid (BemA) in NAFLD and discuss the mechanisms involved.

RECENT FINDINGS

BemA is effective in reducing hepatic steatosis in several animal models that recapitulate different stages of the disease. Thus, in a dietary model of simple hepatic steatosis in female rats, BemA abrogates the accumulation of liver fat. Apart from ACLY inhibition, BemA has several functions in the liver that contribute to the antisteatotic effect: inhibition of ketohexokinase, induction of patatin-like phospholipase domain-containing protein 3 and increases in both fatty acid β-oxidation activity and hepatic H2S production. In models of the advanced phases of NAFLD, BemA reduces not only steatosis, but also ballooning, lobular inflammation and hepatic fibrosis, by mechanisms involving both hepatocytes and hepatic stellate cells.

SUMMARY

BemA, an ACLY inhibitor currently approved for the treatment of hypercholesterolemia, may be a useful drug to treat NAFLD through its antisteatotic, anti-inflammatory and antifibrotic effects.

ncRNA-mediated fatty acid metabolism reprogramming in HCC

The challenges of hepatocellular carcinoma (HCC) pathogenesis, diagnosis, treatment, and prognosis evaluation are obvious. Hepatocyte-specific fatty acid (FA) metabolic reprogramming is an important marker of liver carcinogenesis and progression; elucidating its mechanism will help unravel the complexity of HCC pathogenesis. Noncoding RNAs (ncRNAs) play important roles in HCC development. Moreover, ncRNAs are important mediators of FA metabolism and are directly involved in the reprogramming of FA metabolism in HCC cells. Here we review significant new advances in understanding the mechanisms regulating HCC metabolism by focusing on ncRNA-mediated post-translational modifications of metabolic enzymes, metabolism-related transcription factors, and other proteins in associated signaling pathways. We also discuss the great therapeutic potential of targeting ncRNA-mediated FA metabolism reprogramming in HCC.

Fatty acid metabolism reprogramming in ccRCC: mechanisms and potential targets

Lipid droplet formation is a defining histological feature in clear-cell renal cell carcinoma (ccRCC) but the underlying mechanisms and importance of this biological behaviour have remained enigmatic. De novo fatty acid (FA) synthesis, uptake and suppression of FA oxidation have all been shown to contribute to lipid storage, which is a necessary tumour adaptation rather than a bystander effect. Clinical studies and mechanistic investigations into the roles of different enzymes in FA metabolism pathways have revealed new metabolic vulnerabilities that hold promise for clinical effect. Several metabolic alterations are associated with worse clinical outcomes in patients with ccRCC, as lipogenic genes drive tumorigenesis. Enzymes involved in the intrinsic FA metabolism pathway include FA synthase, acetyl-CoA carboxylase, ATP citrate lyase, stearoyl-CoA desaturase 1, cluster of differentiation 36, carnitine palmitoyltransferase 1A and the perilipin family, and each might be potential therapeutic targets in ccRCC owing to the link between lipid deposition and ccRCC risk. Adipokines and lipid species are potential biomarkers for diagnosis and treatment monitoring in patients with ccRCC. FA metabolism could potentially be targeted for therapeutic intervention in ccRCC as small-molecule inhibitors targeting the pathway have shown promising results in preclinical models.

Mechanisms of unusual response to lipid-lowering therapy: PCSK9 inhibition

The efficacy of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition has broadened lipid-lowering therapy thus providing decreased risk in atherosclerotic cardiovascular disease. Unfortunately, the widespread use of PCSK9 inhibitors (PCSK9i), ie, monoclonal antibodies, has led to the findings of unusual responsiveness, ie, a phenomenon defined as an LDL-C reduction of <30% vs the average LDL-C reduction efficacy of 50-60%. This unusual responsiveness to PCSK9i is attributable to several factors, ie, lack of adherence, impaired absorption, poor distribution or early elimination as well as abnormal effects of PCSK9i in the presence of anti-antibodies or mutations in PCSK9 and LDLR. Unexpectedly increased lipoprotein (Lp)(a) also appear to contribute to the unusual responsiveness scenario. Identification of these responses and mechanisms underlying them are essential for effective management of LDL-C and cardiovascular risk. In this review, we describe plausible reasons underlying this phenomenon supported by findings of clinical trials. We also elaborate on the need for education and regular follow-up to improve adherence. Collectively, the review provides a summary of the past, present, and future of mechanisms and countermeasures revolving around unusual responses to PCSK9i therapy.

Review of recent clinical trials and their impact on the treatment of hypercholesterolemia

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death in the United States with incidence expected to increase in the coming decades. Recent years have produced a variety of new and novel therapeutics aimed at reducing the global burden of cardiovascular disease. This review highlights these recent advancements.

RECENT FINDINGS

In addition to more rigorous therapeutic thresholds for traditional LDL lowering agents such as statins, recent studies have developed new pathways of lipid lowering for both typical cardiovascular disease and complex, genetic lipid disorders. This includes inhibition of the cholesterol synthesis enzyme ATP citrate lyase with bempedoic acid, prevention of PCSK9 mRNA translation with inclisiran, inhibition of the lipoprotein lipase inhibitor angiopoetin like 3 protein with evinacumab and the use of anti-sense oligonucleotides to lower lipoprotein(a) levels. Icosapent ethyl, while remaining a topic of debate and controversy, demonstrates efficacy in cardiovascular risk reduction when all available data are examined. Lastly fibrate therapy continues to produce negative results in terms of cardiovascular disease reduction.

SUMMARY

Recent years have yielded breadth and depth to cardiovascular treatments. This expanded armamentarium will allow for more effective and more consistent treatment and prevention of cardiovascular disease.

Discovery and characterization of novel ATP citrate lyase inhibitors from natural products by a luminescence-based assay

ATP citrate lyase (ACLY) is a key enzyme in glucolipid metabolism with therapeutic prospect for treating hyperlipidemia and various cancers. Much effort has been put into discovering ACLY inhibitors. However, current screening approaches have limitations in sensitivity, portability and high-throughput. To develop a general screening assay, we investigated series of conditions affecting the enzymatic reaction based on the ADP-Glo luminescence assay. Bovine serum albumin (0.001%) added triggered strong and stable fluorescence signal. The optimized assay was validated and applied to screen our natural product library. Two novel inhibitors were identified with IC₅₀ values of 3.86 ± 0.62 μM (2) and 15.48 ± 2.51 μM (4). Their aggregations and target specificities were also examined. 2 was characterized as a noncompetitive inhibitor of ACLY, while 4 was a competitive inhibitor of CoA, which was also elucidated by docking studies. In anticancer activity evaluation, 2 with higher inhibition potency did not exhibit anticancer effect, probably owing to its insufficient cell-permeability. 4 showed moderate inhibition in the proliferation of A549 and PC3 cells. This study not only developed a general approach for ACLY inhibitor discovery, but also identified a new scaffold ACLY inhibitor, which could be served as a hit compound in drug design.

Major Concepts in Treatment with Bempedoic Acid and Inclisiran that Clinicians Need To Know

PURPOSE OF REVIEW

There have been recent developments of novel therapeutic agents for lipid lowering. This article reviews treatment concepts for two of the newest lipid-lowering medications.

RECENT FINDINGS

Bempedoic acid inhibits adenosine citrate lyase, decreasing intracellular lipogenesis. This oral medication is a prodrug and requires activation by enzymes present in hepatocytes but absent in the skeletal muscle. Clinical trials demonstrated additive benefit with statin therapy, and it was well tolerated in statin-intolerant populations. Inclisiran uses RNA interference to prevent translation of PCSK9 mRNA. Due to its stability, it can be given as an injection every 6 months and produces consistent, durable, and potent cholesterol lowering. Bempedoic acid and inclisiran represent new avenues of treatment for the prevention and treatment of cardiovascular disease. This will allow for more comprehensive care by addressing challenges with medication adherence, such as adverse effects to prior medications as well as ease of dosing.

Role of Bempedoic Acid in Clinical Practice

Many patients do not achieve optimal low-density lipoprotein cholesterol (LDL-C) levels with statins alone; others are unable to tolerate statin therapy. Additional non-statin treatment options including ezetimibe, proprotein convertase subtilisin/kexin type 9 inhibitors, and bile acid sequestrants are often necessary to further reduce the risk of atherosclerotic cardiovascular disease. This review provides practical guidance as to the use of bempedoic acid to lower LDL-C and includes direction as to which patients may benefit and advice for safety monitoring during treatment. Bempedoic acid, a new class of agent, is a prodrug converted to bempedoyl-CoA by very long-chain acyl-CoA synthetase 1, an enzyme with high expression in the liver but that is undetectable in the skeletal muscle. Bempedoic acid inhibits the enzyme adenosine triphosphate (ATP)-citrate lyase, which lies two steps upstream from β-hydroxy β-methylglutaryl-CoA reductase in the cholesterol biosynthesis pathway. In clinical trials conducted in patients with or at risk for atherosclerotic cardiovascular disease or familial heterozygous hypercholesterolemia, bempedoic acid in combination with statins and/or ezetimibe significantly reduced LDL-C, apolipoprotein B, and high-sensitivity C-reactive protein compared with placebo. Bempedoic acid is generally well tolerated with no clinically meaningful increase in muscle-related symptoms relative to placebo, even in patients taking maximally tolerated statins. A small increase in serum uric acid (mean increase 0.8 mg/dL) is the most noteworthy adverse effect. Bempedoic acid provides an effective and generally well-tolerated medication to further reduce LDL-C in patients taking maximally tolerated statins or manage LDL-C levels in those who are unable to take statins. The potential for a reduced incidence of major cardiovascular events with bempedoic acid is being investigated in the CLEAR Outcomes trial, with results expected in 2023.

Evaluating pharmacokinetics of bempedoic acid in the treatment of hypercholesterolemia

Introduction: Bempedoic acid is a first-in-class low-density lipoprotein cholesterol (LDL-C) lowering agent which offers an important opportunity for further LDL-C lowering in statin-intolerant patients or in patients requiring further LDL-C reduction despite maximally tolerated statin therapy.Areas covered: In this review, we examined the pharmacodynamics, pharmacokinetics, clinical efficacy, and safety of bempedoic acid, based on randomized clinical phase III clinical studies and their meta-analyses.Expert opinion: Unlike statins, bempedoic acid is administered as a prodrug and is converted to active form by a liver-specific enzyme. For the liver-specific mechanism of action, bempedoic acid has the potential to reduce the risk of muscle-related adverse events which can limit the utilization and effectiveness of statin therapy.

Bempedoic Acid for Heterozygous Familial Hypercholesterolemia: From Bench to Bedside

Bempedoic acid is a first-in-class, oral, inhibitor of cholesterol biosynthesis that is approved for use in patients with atherosclerotic cardiovascular disease (ASCVD) and for primary prevention in individuals with heterozygous familial hypercholesterolemia (HeFH) by the United States Food and Drug Administration. Pooled data from the phase III clinical trials, CLEAR Harmony and CLEAR Wisdom, have demonstrated the safety and efficacy of bempedoic acid with regard to lowering of low-density lipoprotein cholesterol (LDL-C) in patients with HeFH as an adjunct or alternative to currently existing lipid-lowering therapies. CLEAR Outcomes is a cardiovascular outcomes trial that is currently underway that will provide additional insight as to where bempedoic acid will fit into treatment regimens among the non-statin lipid-lowering therapy options. Patients who might particularly benefit from bempedoic acid are those with HeFH and those unable to take adequate doses of statins or take any statin therapy altogether who need additional LDL-C lowering. In this review, we will discuss the profile of bempedoic acid from its design, development, and its place in therapy for the management of LDL-C for the purposes of ASCVD prevention.

Updated clinical evidence and place in therapy of bempedoic acid for hypercholesterolemia: ANMCO position paper

The central role of high low-density lipoprotein cholesterol levels in atherosclerotic cardiovascular disease has led to research focused on lipid-lowering agents for cardiovascular risk reduction. Bempedoic acid is an emerging treatment for hypercholesterolemia that has recently been approved for marketing in the United States and Europe. This review focuses on its mechanism of action and summarizes the main preclinical study findings. Furthermore, we report the clinical evidence supporting and guiding its use in hypercholesterolemia management.

Bempedoic acid: a promising novel agent for LDL-C lowering

Bempedoic acid (ETC-1002) is a novel, first-in-class, oral, small molecule that inhibits cholesterol biosynthesis in the same pathway as statins, thereby lowering low-density lipoprotein cholesterol (LDL-C) by upregulating LDL receptors. Preclinical and completed Phase II and III clinical trials have demonstrated promising results regarding its safety and efficacy across a variety of patient characteristics including statin intolerance and on a background of lipid-lowering therapy. Bempedoic acid is currently being evaluated in a cardiovascular outcomes trial to evaluate its effect on major cardiovascular events in patients with or at high risk for cardiovascular disease and with statin intolerance. In this review, we will discuss the history and development of bempedoic acid, relevant clinical trials, and its potential role as a lipid-lowering medication in the context of other currently available lipid-lowering therapies.

Efficacy and safety of bempedoic acid for the treatment of hypercholesterolemia: A systematic review and meta-analysis

BACKGROUND

Bempedoic acid is a first-in-class lipid-lowering drug recommended by guidelines for the treatment of hypercholesterolemia. Our objective was to estimate its average effect on plasma lipids in humans and its safety profile.

METHODS AND FINDINGS

We carried out a systematic review and meta-analysis of phase II and III randomized controlled trials on bempedoic acid (PROSPERO: CRD42019129687). PubMed (Medline), Scopus, Google Scholar, and Web of Science databases were searched, with no language restriction, from inception to 5 August 2019. We included 10 RCTs (n = 3,788) comprising 26 arms (active arm [n = 2,460]; control arm [n = 1,328]). Effect sizes for changes in lipids and high-sensitivity C-reactive protein (hsCRP) serum concentration were expressed as mean differences (MDs) and 95% confidence intervals (CIs). For safety analyses, odds ratios (ORs) and 95% CIs were calculated using the Mantel-Haenszel method. Bempedoic acid significantly reduced total cholesterol (MD -14.94%; 95% CI -17.31%, -12.57%; p < 0.001), non-high-density lipoprotein cholesterol (MD -18.17%; 95% CI -21.14%, -15.19%; p < 0.001), low-density lipoprotein cholesterol (MD -22.94%; 95% CI -26.63%, -19.25%; p < 0.001), low-density lipoprotein particle number (MD -20.67%; 95% CI -23.84%, -17.48%; p < 0.001), apolipoprotein B (MD -15.18%; 95% CI -17.41%, -12.95%; p < 0.001), high-density lipoprotein cholesterol (MD -5.83%; 95% CI -6.14%, -5.52%; p < 0.001), high-density lipoprotein particle number (MD -3.21%; 95% CI -6.40%, -0.02%; p = 0.049), and hsCRP (MD -27.03%; 95% CI -31.42%, -22.64%; p < 0.001). Bempedoic acid did not significantly modify triglyceride level (MD -1.51%; 95% CI -3.75%, 0.74%; p = 0.189), very-low-density lipoprotein particle number (MD 3.79%; 95% CI -9.81%, 17.39%; p = 0.585), and apolipoprotein A-1 (MD -1.83%; 95% CI -5.23%, 1.56%; p = 0.290). Treatment with bempedoic acid was positively associated with an increased risk of discontinuation of treatment (OR 1.37; 95% CI 1.06, 1.76; p = 0.015), elevated serum uric acid (OR 3.55; 95% CI 1.03, 12.27; p = 0.045), elevated liver enzymes (OR 4.28; 95% CI 1.34, 13.71; p = 0.014), and elevated creatine kinase (OR 3.79; 95% CI 1.06, 13.51; p = 0.04), though it was strongly associated with a decreased risk of new onset or worsening diabetes (OR 0.59; 95% CI 0.39, 0.90; p = 0.01). The main limitation of this meta-analysis is related to the relatively small number of individuals involved in the studies, which were often short or middle term in length.

CONCLUSIONS

Our results show that bempedoic acid has favorable effects on lipid profile and hsCRP levels and an acceptable safety profile. Further well-designed studies are needed to explore its longer-term safety.

Metabolic Routes in Inflammation: The Citrate Pathway and its Potential as Therapeutic Target

Significant metabolic changes occur in inflammation to respond to the new energetic needs of cells. Mitochondria are addressed not only to produce ATP, but also to supply substrates, such citrate, to produce pro-inflammatory molecules. In this context, most of the citrate is diverted from Krebs cycle and channeled into the "citrate pathway" leading to the increase in the export of citrate into cytosol by the Mitochondrial Citrate Carrier (CIC) followed by its cleavage into acetyl-CoA and oxaloacetate by ATP Citrate Lyase (ACLY). Acetyl- CoA is used to produce PGE2 and oxaloacetate to make NADPH needed for NO and ROS production. In addition, cytosolic citrate also provides precursors for itaconate synthesis. Citrate- derived itaconate acts as a negative regulator of inflammation by modulating the synthesis of the inflammatory mediators. Inhibition of CIC or ACLY by different synthetic and natural molecules results in the reduction of NO, ROS and PGE2 levels suggesting that the citrate pathway can be a new target to be addressed in inflammation. Beneficial effects can be obtained also in the oxidative stress and inflammatory conditions observed in Down syndrome.

The vital role of ATP citrate lyase in chronic diseases

Chronic or non-communicable diseases are the leading cause of death worldwide; they usually result in long-term illnesses and demand long-term care. Despite advances in molecular therapeutics, specific biomarkers and targets for the treatment of these diseases are required. The dysregulation of de novo lipogenesis has been found to play an essential role in cell metabolism and is associated with the development and progression of many chronic diseases; this confirms the link between obesity and various chronic diseases. The main enzyme in this pathway-ATP-citrate lyase (ACLY), a lipogenic enzyme-catalyzes the critical reaction linking cellular glucose catabolism and lipogenesis. Increasing lines of evidence suggest that the modulation of ACLY expression correlates with the development and progressions of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases, diabetes, obesity, inflammation, and cancer. Recent studies suggest that the inhibition of ACLY activity modulates the glycolysis and lipogenesis processes and stimulates normal physiological functions. This comprehensive review aimed to critically evaluate the role of ACLY in the development and progression of different diseases and the effects of its downregulation in the prevention and treatment of these diseases.

ATP-citrate lyase (ACLY) in lipid metabolism and atherosclerosis: An updated review

ATP citrate lyase (ACLY) is an important enzyme linking carbohydrate to lipid metabolism by generating acetyl-CoA from citrate for fatty acid and cholesterol biosynthesis. Mendelian randomization of large human cohorts has validated ACLY as a promising target for low-density-lipoprotein-cholesterol (LDL-C) lowering and cardiovascular protection. Among current ACLY inhibitors, Bempedoic acid (ETC-1002) is a first-in-class, prodrug-based direct competitive inhibitor of ACLY which regulates lipid metabolism by upregulating hepatic LDL receptor (LDLr) expression and activity. ACLY deficiency in hepatocytes protects from hepatic steatosis and dyslipidemia. In addition, pharmacological inhibition of ACLY by bempedoic acid, prevents dyslipidemia and attenuates atherosclerosis in hypercholesterolemic ApoE^-/- mice, LDLr^-/- mice, and LDLr^-/- miniature pigs. Convincing data from clinical trials have revealed that bempedoic acid significantly lowers LDL-C as monotherapy, combination therapy, and add-on with statin therapy in statin-intolerant patients. More recently, a phase 3 CLEAR Harmony clinical trial ("Safety and Efficacy of Bempedoic Acid to Reduce LDL Cholesterol") has shown that bempedoic acid reduces the level of LDL-C in hypercholesterolemic patients receiving guideline-recommended statin therapy with a good safety profile. Hereby, we provide a updated review of the expression, regulation, genetics, functions of ACLY in lipid metabolism and atherosclerosis, and highlight the therapeutic potential of ACLY inhibitors (such as bempedoic acid, SB-204990, and other naturally-occuring inhibitors) to treat atherosclerotic cardiovascular diseases. It must be pointed out that long-term large-scale clinical trials in high-risk patients, are warranted to validate whether ACLY represent a promising therapeutic target for pharmaceutic intervention of dyslipidemia and atherosclerosis; and assess the safety and efficacy profile of ACLY inhibitors in improving cardiovascular outcome of patients.

Aberrant lipid metabolism as a therapeutic target in liver cancer

INTRODUCTION

Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers. Progress has been made in treatment of HCC; however, improved outcomes are much needed. The increased metabolic needs of cancer cells underscore the importance of metabolic pathways in cancer cell survival. Lipid metabolism has a role in HCC development; aberrant overexpression of several key enzymes is seen in many solid human tumors. Areas covered: We discuss aberrant lipid metabolism and the promise of multiple targets, in particular related to HCC treatment. We searched PubMed and clinicaltrials.gov for published and unpublished studies from 2000 to 2019. These terms were used: lipids, fatty acid metabolism, lipid metabolism, liver cancer, HCC, de novo fatty acid synthesis, ATP citrate lyase, stearoyl CoA denaturase, fatty acid synthase, acetyl coenzyme A carboxylase, CD147, KLF4, monoglyceride lipase, AMP activated protein kinase. Expert opinion: The importance of dysregulation of fatty acid synthesis in cancer is a growing area of research. HCC demonstrates significant alteration in lipid metabolism, representing great potential as a target for novel therapeutics. Various agents have demonstrated promising anti-neoplastic activity. This strategy deserves further development for improved outcomes.

Comparative de novo flower transcriptome analysis of polygamodioecious tree Garcinia indica

To extend our understanding of molecular mechanism of sex determination in agro-economically important, polygamodioecious tree Garcinia indica (Kokum), high-throughput, next-generation flower transcriptome sequencing (NGS), and comparative analyses were performed to investigate differentially expressed gene in bisexual, female, and male flowers. A total of 49414 unigenes in BS, 45944 unigenes in FL, and 49028 unigenes in ML flowers were annotated. KO annotations revealed that 25 functional categories were large number of genes which were annotated to 'signal transduction'. We identified 33 genes for 'auxin response factor' and 50 for 'ethylene-responsive factor' whose expression changed significantly in all the three paired library combinations. Furthermore, key regulators of floral development such as FLC, SVP, AP1, AP2, AP3, AG, AGL2, AGL4, AGL9, and PI were identified. A total of 327 differentially expressed MADS-box genes were identified in G. indica transcriptome. Analysis of MADS-box genes identified five genes such as MADS AGL11, CRS2-associated factor chloroplastic, conserved hypothetical protein, uncharacterized protein LOC104422218, and MADS-box JOINTLESS-like isoform X3 significantly expressed in only FL flower. In addition, number of DEGs like dynamin 2A, auxin response factor, and spermidine synthase involved in sex expression and reproduction were discovered. The expression patterns of selected genes matched well with the expression levels of unigenes by transcriptome sequencing. Our large-scale comparative analyses may provide valuable hints for the next insights into the molecular mechanism of sex determination in G. indica.

ETC-1002 (Bempedoic acid) for the management of hyperlipidemia: from preclinical studies to phase 3 trials

INTRODUCTION

Tolerability problems in treating hypercholesterolemic patients undergoing statin treatment are of growing concern to physicians and patients, thus underlining the need for an agent with a similar mechanism but minimal side effects. A drug with a somewhat similar mechanism to statins but free of muscular side effects is ETC-1002 (bempedoic acid). It inhibits cholesterol biosynthesis at a step preceding HMG-CoA reductase, i.e. ATP citrate lyase (ACLY). A prodrug, ETC-1002 is converted to the active agent only in liver, not in skeletal muscle, and this may prevent any myotoxic activity. Area covered: The mechanism of ETC-1002 activity is described in detail, considering that ACLY inhibition markedly attenuated atherosclerosis in animal models. Clinical studies are also reported. Expert opinion: Present day LDL-C lowering treatments lead to significant reductions of cardiovascular (CV) events but, at times, the need to interrupt statin treatment appears to be dangerous due to a rapid rise in CV risk. The excellent tolerability of ETC-1002 makes it a useful alternative, either alone or as an adjunct to ezetimibe, for patients with statin intolerance needing to achieve significant CV risk reduction. ETC-1002 is also associated with a marked fall in high-sensitivity C-reactive protein.

The main beneficial effect of roselle (Hibiscus sabdariffa) on obesity is not only related to its anthocyanin content

BACKGROUND

The calyxes of roselle (Hibiscus sabdariffa) are recognized for their high nutraceutical value because they decrease body weight and obesity complications. These effects have been attributed mainly to anthocyanins. However, the calyxes comprise important concentration of flavonoids, phenolic, and organic acids, which could also contribute to these effects. The objective of this work was to determine the effect of the Alma Blanca white roselle variety on obesity and hepatic steatosis in high-fat, high-fructose, diet-fed rats and compare its beneficial effects with the red variety (Criolla), which has been more extensively studied.

RESULTS

Aqueous and methanolic extracts were prepared from two roselle varieties, Alma Blanca (white) and Criolla (red). The phytochemical profiles were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Criolla extracts contain principally anthocyanins, phenolic acids, and flavonoids. Anthocyanins were not detected in Alma Blanca. The aqueous extracts of both varieties prevented body-weight gain and decreased adipocytes hyperplasia on rats fed a hypercaloric diet. These extracts also protected against hepatic steatosis. These benefits were associated with hibiscus, dimethyl hibiscus, and hydroxycitric acid.

CONCLUSION

These results demonstrated that calyxes from Hibiscus sabdariffa contain compounds that are different from anthocyanins, with potential benefits to health. The organic acids were strongly associated with these beneficial health effects. © 2018 Society of Chemical Industry.

Novel Therapeutic Targets for Managing Dyslipidemia

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of morbidity and mortality in developed nations. Therapeutic modulation of dyslipidemia by inhibiting 3'-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is standard practice throughout the world. However, based on findings from Mendelian studies and genetic sequencing in prospective longitudinal cohorts from around the world, novel therapeutic targets regulating lipid and lipoprotein metabolism, such as apoprotein C3, angiopoietin-like proteins 3 and 4, and lipoprotein(a), have been identified. These targets may provide additional avenues to prevent and treat atherosclerotic disease. We therefore review these novel molecular targets by addressing available Mendelian and observational data, therapeutic agents in development, and early outcomes results.

Targeting ATP-Citrate Lyase in Hyperlipidemia and Metabolic Disorders

Chronic overnutrition and a sedentary lifestyle promote imbalances in metabolism, often manifesting as risk factors for life-threating diseases such as atherosclerotic cardiovascular disease (ASCVD) and nonalcoholic fatty liver disease (NAFLD). Nucleocytosolic acetyl-coenzyme A (CoA) has emerged as a central signaling node used to coordinate metabolic adaptations in response to a changing nutritional status. ATP-citrate lyase (ACL) is the enzyme primarily responsible for the production of extramitochondrial acetyl-CoA and is thus strategically positioned at the intersection of nutrient catabolism and lipid biosynthesis. Here, we discuss recent findings from preclinical studies, as well as Mendelian and clinical randomized trials, demonstrating the importance of ACL activity in metabolism, and supporting its inhibition as a potential therapeutic approach to treating ASCVD, NAFLD, and other metabolic disorders.

Bempedoic Acid (ETC-1002): an Investigational Inhibitor of ATP Citrate Lyase

Bempedoic acid (ETC-1002), a novel therapeutic approach for low-density lipoprotein cholesterol (LDL-C) lowering, inhibits ATP citrate lyase (ACL), an enzyme involved in fatty acid and cholesterol synthesis. Although rodent studies suggested potential effects of ACL inhibition on both fatty acid and cholesterol synthesis, studies in humans show an effect only on cholesterol synthesis. In phase 2 studies, ETC-1002 reduced LDL-C as monotherapy, combined with ezetimibe, and added to statin therapy, with LDL-C lowering most pronounced when ETC-1002 was combined with ezetimibe in patients who cannot tolerate statins. Whether clinically relevant favorable effects on other cardiometabolic risk factors such as hyperglycemia and insulin resistance occur in humans is unknown and requires further investigation. Promising phase 2 results have led to the design of a large phase 3 program to gain more information on efficacy and safety of ETC-1002 in combination with statins and when added to ezetimibe in statin-intolerant patients.

Liver-specific ATP-citrate lyase inhibition by bempedoic acid decreases LDL-C and attenuates atherosclerosis

Despite widespread use of statins to reduce low-density lipoprotein cholesterol (LDL-C) and associated atherosclerotic cardiovascular risk, many patients do not achieve sufficient LDL-C lowering due to muscle-related side effects, indicating novel treatment strategies are required. Bempedoic acid (ETC-1002) is a small molecule intended to lower LDL-C in hypercholesterolemic patients, and has been previously shown to modulate both ATP-citrate lyase (ACL) and AMP-activated protein kinase (AMPK) activity in rodents. However, its mechanism for LDL-C lowering, efficacy in models of atherosclerosis and relevance in humans are unknown. Here we show that ETC-1002 is a prodrug that requires activation by very long-chain acyl-CoA synthetase-1 (ACSVL1) to modulate both targets, and that inhibition of ACL leads to LDL receptor upregulation, decreased LDL-C and attenuation of atherosclerosis, independently of AMPK. Furthermore, we demonstrate that the absence of ACSVL1 in skeletal muscle provides a mechanistic basis for ETC-1002 to potentially avoid the myotoxicity associated with statin therapy.

Effect of ETC-1002 on Serum Low-Density Lipoprotein Cholesterol in Hypercholesterolemic Patients Receiving Statin Therapy

ETC-1002 is an oral, once-daily medication that inhibits adenosine triphosphate citrate lyase, an enzyme upstream of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, to reduce cholesterol biosynthesis. ETC-1002 monotherapy has demonstrated significant reduction in low-density lipoprotein cholesterol (LDL-C) compared with placebo in phase 2 studies. The objective of this study was to compare the lipid-lowering efficacy of ETC-1002 versus placebo when added to ongoing statin therapy in patients with hypercholesterolemia. This phase 2b, multicenter, double-blind trial (NCT02072161) randomized 134 hypercholesterolemic patients (LDL-C, 115 to 220 mg/dl) on stable background statin therapy to 12 weeks of add-on treatment with ETC-1002 120 mg, ETC-1002 180 mg, or placebo. The primary efficacy end point was the percent change in calculated LDL-C from baseline to week 12. For LDL-C, the least-squares mean percent change ± standard error from baseline to week 12 was significantly greater with ETC-1002 120 mg (-17 ± 4%, p = 0.0055) and ETC-1002 180 mg (-24 ± 4%, p <0.0001) than placebo (-4 ± 4%). ETC-1002 also dose dependently reduced apolipoprotein B by 15% to 17%, non-high-density lipoprotein cholesterol by 14% to 17%, total cholesterol by 13% to 15%, and LDL particle number by 17% to 21%. All these reductions in ETC-1002-treated cohorts were significantly greater than those with placebo. Rates of adverse events (AEs), muscle-related AEs, and discontinuations for AEs with ETC-1002 were similar to placebo. In conclusion, ETC-1002 120 mg or 180 mg added to stable statin therapy significantly reduced LDL-C compared to placebo and has a similar tolerability profile.

(-)-Hydroxycitric acid reduced fat deposition via regulating lipid metabolism-related gene expression in broiler chickens

BACKGROUND

Chicken as a delicious food for a long history, and it is well known that excess fat deposition in broiler chickens will not only induced metabolic diseases, but also lead to adverse effect in the consumer's health. (-)-Hydroxycitric acid (HCA), a major active ingredient of Garcinia Cambogia extracts, had shown to suppress fat accumulation in animals and humans. While, the precise physiological mechanism of HCA has not yet been full clarified, especially its action in broiler chickens. Thus, this study aimed to assess the effect of (-)-HCA on lipid metabolism in broiler chickens.

METHODS

A total of 120 1-day-old broiler chickens were randomly allocated to four groups, with each group was repeated three times with 10 birds. Birds received a commercial diet supplemented with (-)-HCA at 0, 1000, 2000 or 3000 mg/kg, respectively, for a period of 4 weeks ad libitum.

RESULTS

Body weight (BW) in the 2000 and 3000 mg/kg (-)-HCA groups was significantly decreased (P < 0.05) than that in control group. A significantly decreased of serum triglyceride (TG) and density lipoprotein-cholesterol (LDL-C) content were observed in 3000 mg/kg (-)-HCA group (P < 0.05). Broiler chickens supplmented with 2000 and 3000 mg/kg (-)-HCA had pronouncedly higher hepatic lipase (HL) activity, hepatic glycogen and non-esterified fatty acid (NEFA) contents in liver (P < 0.05). Serum free triiodothyronine (FT3) and thyroxin (T4) contents were significantly higher in 3000 mg/kg (-)-HCA group (P < 0.05) compared with the control group. Supplemental (-)-HCA markedly decreased fatty acid synthase (FAS) and sterol regulatory element binding protein-1c (SREBP-1c) (P < 0.05) mRNA levels, while the mRNA abundance of adenosine 5'-monophosphate-activated protein kinaseβ2 (AMPKβ2) (P < 0.05) was significantly increased. In addition, ATP-citrate lyase (ACLY) mRNA level (P < 0.05) was significantly decreased in broiler chickens supplemented with 3000 mg/kg (-)-HCA. No differences was observed on carnitine palmitoyl transferase-I(CPT-I), while peroxisome proliferators-activated receptor α (PPARα) mRNA level (P < 0.05) was significantly increased in broiler chickens supplemented with 2000 and 3000 mg/kg (-)-HCA.

CONCLUSIONS

Supplemental (-)-HCA inhibited lipogenesis by inhibiting ACLY, SREBP-1c and FAS expression, and accelerated lipolysis through enhancing HL activity and PPARα expression, which eventually led to the reduced abdominal fat deposition in broiler chickens. Graphical abstract Mechanism of (-)-HCA effect on hepatic lipids metabolism.

Treatment with ETC-1002 alone and in combination with ezetimibe lowers LDL cholesterol in hypercholesterolemic patients with or without statin intolerance

BACKGROUND

ETC-1002 is an oral, once-daily, first-in-class medication being developed to treat hypercholesterolemia.

OBJECTIVES

To compare 2 doses of ETC-1002, alone or combined with ezetimibe 10 mg (EZE), vs EZE monotherapy for lowering low-density lipoprotein cholesterol (LDL-C).

METHODS

This phase 2b, multicenter, double-blind trial-evaluated hypercholesterolemic patients (LDL-C, 130 to 220 mg/dL) with (n = 177) or without (n = 171) muscle-related intolerance to ≥2 statins; 1 at lowest approved dose. Subjects were randomized to 12-week treatment with ETC-1002 120 mg or ETC-1002 180 mg alone, EZE alone, ETC-1002 120 mg plus EZE, or ETC-1002 180 mg plus EZE.

RESULTS

EZE alone lowered LDL-C by 21%, whereas ETC-1002 monotherapy with 120 mg or 180 mg reduced LDL-C by 27% (P = .0008 vs EZE) and 30% (P < .0001 vs EZE), respectively. The combination of ETC-1002, 120 mg or 180 mg plus EZE reduced LDL-C by 43% and 48%, respectively (both P < .0001 vs EZE). ETC-1002 alone or combined with EZE also reduced non-high-density lipoprotein cholesterol, total cholesterol, apolipoprotein B, LDL particle number, and high-sensitivity C-reactive protein compared with EZE alone. Across all treatment groups, statin-intolerant patients reported more muscle-related adverse events than did statin-tolerant patients. ETC-1002 was safe and well tolerated, and rates of muscle-related adverse events were similar in all treatment groups.

CONCLUSIONS

In patients with and without statin intolerance, daily treatment with ETC-1002 120 mg and 180 mg alone or with EZE reduced LDL-C more than EZE alone and had a similar tolerability profile (NCT01941836).

Recent developments in modulating atherogenic lipoproteins

PURPOSE OF REVIEW

Randomized clinical trials have assessed the effects of several classes of drugs on plasma cholesterol levels in patients with coronary artery disease. Agents including niacin, fibrates and statins significantly lower LDL-cholesterol, but tolerance issues and undesirable side-effects are common. Residual risk may also be present in patients with persistently low HDL-cholesterol despite a reduction in LDL-cholesterol. Recent trials of drugs that increase circulating HDL-cholesterol have also been disappointing.

RECENT FINDINGS

Ongoing efforts target the development of new pharmacotherapies to reduce circulating levels of atherogenic lipoproteins. The goal of this review is to discuss recent advances in the treatment of coronary artery disease and other vascular diseases characterized by an increase in circulating atherogenic lipoproteins. These include the development of inhibitors of ATP citrate lyase and proprotein convertase subtilisin/kexin type 9. We also discuss recent developments in HDL therapy, including the clinical assessment of cholesteryl ester transfer protein inhibitors and apolipoprotein E mimetic peptides.

SUMMARY

Several new classes of drug are undergoing clinical evaluation that show promise for atherogenic lipoprotein reduction in patients who are statin intolerant.

LDL-cholesterol reduction in patients with hypercholesterolemia by modulation of adenosine triphosphate-citrate lyase and adenosine monophosphate-activated protein kinase

PURPOSE OF REVIEW

To review the profile of ETC-1002, as shown in preclinical and clinical studies, including LDL-cholesterol (LDL-C)-lowering activity and beneficial effects on other cardiometabolic risk markers as they relate to the inhibition of adenosine triphosphate-citrate lyase and the activation of adenosine monophosphate-activated protein kinase.

RECENT FINDINGS

ETC-1002 is an adenosine triphosphate-citrate lyase inhibitor/adenosine monophosphate-activated protein kinase activator currently in Phase 2b clinical development. In seven Phase 1 and Phase 2a clinical studies, ETC-1002 dosed once daily for 2-12 weeks has lowered LDL-C and reduced high-sensitivity C-reactive protein by up to 40%, with neutral to positive effects on glucose levels, blood pressure, and body weight. Importantly, use of ETC-1002 in statin-intolerant patients has shown statin-like lowering of LDL-C without the muscle pain and weakness responsible for discontinuation of statin use by many patients. ETC-1002 has also been shown to produce an incremental benefit, lowering LDL-C as an add-on therapy to a low-dose statin. In over 300 individuals in studies of up to 12 weeks, ETC-1002 has been well tolerated with no serious adverse effects.

SUMMARY

Because adenosine triphosphate-citrate lyase and adenosine monophosphate-activated protein kinase play central roles in regulating lipid and glucose metabolism, pharmacological modulation of these two enzymes could provide an important therapeutic alternative for statin-intolerant patients with hypercholesterolemia.

Effects of garcinia cambogia (Hydroxycitric Acid) on visceral fat accumulation: a double-blind, randomized, placebo-controlled trial

BACKGROUND

(-)-Hydroxycitric acid (HCA) is an active ingredient extracted from the rind of the Indian fruit Garcinia cambogia. It inhibits adenosine triphosphate citrate lyase and has been used in the treatment of obesity.

OBJECTIVE

The primary end point of this study was the effects of 12 weeks of G cambogia extract administration on visceral fat accumulation. The secondary end points were body indices (including height, body weight, body mass index [BMI], waist and hip circumference, and waist-hip ratio) and laboratory values (including total cholesterol, triacylglycerol, and free fatty acid).

METHODS

This study was performed according to a double-blind, randomized, placebo-controlled, parallel-group design. Subjects aged 20 to 65 years with a visceral fat area >90 cm(2) were enrolled. Subjects were randomly assigned to receive treatment for 12 weeks with G cambogia (containing 1000 mg of HCA per day) or placebo. At the end of the treatment period, both groups were administered placebo for 4 weeks to assess any rebound effect. Each subject underwent a computed tomography scan at the umbilical level at -2, 0, 12, and 16 weeks.

RESULTS

Forty-four subjects were randomized at baseline, and 39 completed the study (G cambogia group, n = 18; placebo group, n = 21). At 16 weeks, the G cambogia group had significantly reduced visceral, subcutaneous, and total fat areas compared with the placebo group (all indices P<0.001). No severe adverse effect was observed at any time in the test period. There were no significant differences in BMI or body weight at week 12, but there were slight numeric decreases in body weight and BMI in men. There were no signs of a rebound effect from week 12 to week 16.

CONCLUSION

G cambogia reduced abdominal fat accumulation in subjects, regardless of sex, who had the visceral fat accumulation type of obesity. No rebound effect was observed. It is therefore expected that G cambogia may be useful for the prevention and reduction of accumulation of visceral fat.

Updates on Antiobesity Effect of Garcinia Origin (-)-HCA

Garcinia is a plant under the family of Clusiaceae that is commonly used as a flavouring agent. Various phytochemicals including flavonoids and organic acid have been identified in this plant. Among all types of organic acids, hydroxycitric acid or more specifically (−)-hydroxycitric acid has been identified as a potential supplement for weight management and as antiobesity agent. Various in vivo studies have contributed to the understanding of the anti-obesity effects of Garcinia/hydroxycitric acid via regulation of serotonin level and glucose uptake. Besides, it also helps to enhance fat oxidation while reducing de novo lipogenesis. However, results from clinical studies showed both negative and positive antiobesity effects of Garcinia/hydroxycitric acid. This review was prepared to summarise the update of chemical constituents, significance of in vivo/clinical anti-obesity effects, and the importance of the current market potential of Garcinia/hydroxycitric acid.

AMP-activated protein kinase and ATP-citrate lyase are two distinct molecular targets for ETC-1002, a novel small molecule regulator of lipid and carbohydrate metabolism

ETC-1002 (8-hydroxy-2,2,14,14-tetramethylpentadecanedioic acid) is a novel investigational drug being developed for the treatment of dyslipidemia and other cardio-metabolic risk factors. The hypolipidemic, anti-atherosclerotic, anti-obesity, and glucose-lowering properties of ETC-1002, characterized in preclinical disease models, are believed to be due to dual inhibition of sterol and fatty acid synthesis and enhanced mitochondrial long-chain fatty acid β-oxidation. However, the molecular mechanism(s) mediating these activities remained undefined. Studies described here show that ETC-1002 free acid activates AMP-activated protein kinase in a Ca(2+)/calmodulin-dependent kinase β-independent and liver kinase β 1-dependent manner, without detectable changes in adenylate energy charge. Furthermore, ETC-1002 is shown to rapidly form a CoA thioester in liver, which directly inhibits ATP-citrate lyase. These distinct molecular mechanisms are complementary in their beneficial effects on lipid and carbohydrate metabolism in vitro and in vivo. Consistent with these mechanisms, ETC-1002 treatment reduced circulating proatherogenic lipoproteins, hepatic lipids, and body weight in a hamster model of hyperlipidemia, and it reduced body weight and improved glycemic control in a mouse model of diet-induced obesity. ETC-1002 offers promise as a novel therapeutic approach to improve multiple risk factors associated with metabolic syndrome and benefit patients with cardiovascular disease.

A mixture of the aqueous extract of Garcinia cambogia, soy peptide and L: -carnitine reduces the accumulation of visceral fat mass in rats rendered obese by a high fat diet

The aim of the present study was to investigate the anti-obesity effect of a mixture composed of Garcinia cambogia extract, soypeptide, and L: -carnitine (1.2:0.3:0.02, w/w/w) in rats rendered obese by a high-fat diet (HFD). Sprague-Dawley rats were fed either the high-fat control diet (CD) or the 0.38% mixture-supplemented HFD (CD + M) for 9 weeks. The mixture significantly reduced body weight gain and the accumulation of visceral fat mass in a rat model of HFD-induced obesity. Moreover, the mixture effectively lowered blood and hepatic lipid concentrations and serum glucose, insulin, c-peptide, and leptin levels in rats with HFD-induced obesity. Results from real-time reverse transcription-polymerase chain reaction analyses indicated that the expression levels of leptin, tumor necrosis factor-alpha (TNF-alpha), and sterol regulatory element binding protein 1c (SREBP1c) genes in the epididymal fat tissue of rats fed the CD + M diet were 0.4-, 0.6-, and 0.48-fold, respectively, of those found in the CD rats (P < 0.05), while expression of the uncoupling protein 2 (UCP2) gene in epididymal adipose tissue was 1.25-fold (P < 0.05) of that found in CD rats. In conclusion, a mixture composed of G. cambogia extract, soy peptide, and L: -carnitine attenuated visceral fat accumulation and improved dyslipidemia in a rat model with HFD-induced obesity.

ATP-citrate lyase reduction mediates palmitate-induced apoptosis in pancreatic beta cells

Elevated extracellular lipids, such as the free fatty acid palmitate, can induce pancreatic beta cell endoplasmic reticulum (ER) stress and apoptosis, thereby contributing to the initiation and progression of type 2 diabetes. ATP-citrate lyase (ACLY), a key enzyme in cellular lipid production, was identified as a palmitate target in a proteomic screen. We investigated the effects of palmitate on ACLY activity and phosphorylation and its role in beta cell ER stress and apoptosis. We demonstrated that treatment of MIN6 cells, mouse islets and human islets with palmitate reduced ACLY protein levels. These in vitro results were validated by our finding that islets from high fat-fed mice had a significant decrease in ACLY, similar to that previously observed in type 2 diabetic human islets. Palmitate decreased intracellular acetyl-CoA levels to a similar degree as the ACLY inhibitor, SB-204990, suggesting a reduction in ACLY activity. ACLY inhibitors alone were sufficient to induce CCAAT/enhancer-binding protein homologues protein (CHOP)-dependent ER stress and caspase-3-dependent apoptosis. Similarly, even modest shRNA-mediated knockdown of ACLY caused a significant increase in beta cell apoptosis and ER stress. The effects of chemical ACLY inhibition and palmitate were non-additive and therefore potentially mediated by a common mechanism. Indeed, overexpression of ACLY prevented palmitate-induced beta cell death. These observations provide new evidence that ACLY expression and activity can be suppressed by exogenous lipids and demonstrate a critical role for ACLY in pancreatic beta cell survival. These findings add to the emerging body of evidence linking beta cell metabolism with programmed cell death.

The biology and chemistry of hyperlipidemia

Coronary arterial diseases are responsible for more deaths than all other associated causes combined. Elevated serum cholesterol levels leading to atherosclerosis can cause coronary heart disease (CHD). Reduction in serum cholesterol levels reduces the risk for CHD, substantially. Medicinal chemists all around the world have been designing, synthesizing, and evaluating a variety of new bioactive molecules for lowering lipid levels. This review summarizes the disorders associated with elevation of lipids in blood and the current strategies to control them. The emphasis has been laid in particular on the new potential biological targets and the possible treatments as well as the current ongoing research status in the field of lipid lowering agents.

Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca2+/K+ bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca2+ (495 mg, 49.5% of RDI) and K+ (720 mg, 15% of RDI). Ca2+ ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K+, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions.

6-hydroxy-4-en-3-one sterols from the marine sponge Iotrochoto birotulata

Five sterols with a nucleus skeleton of 6-hydroxy-4-en-3-one, namely cholesta-6beta-hydroxy-4-en-3-one (1), ergosta-6beta-hydroxy-4,24(28)-dien-3-one (2), ergosta-6alpha-hydroxy-4,24(28)-dien-3-one (3), ergosta-6alpha-hydroxy-4,22-E-dien-3-one (4), and ergosta-28-methyl-6beta-hydroxy-4,24(28)-dien-3-one (5) have been isolated from the marine sponge Iotrochoto birotulata, collected from the southern China sea. Sterols 2-4 are new compounds, and 1 has been isolated from marine organisms for the first time. The structures have been elucidated on the basis of extensive spectroscopic and chemical properties.

High dose of Garcinia cambogia is effective in suppressing fat accumulation in developing male Zucker obese rats, but highly toxic to the testis

We investigated the ability of Garcinia cambogia extract containing (-)-hydroxycitric acid (HCA) to suppress body fat accumulation in developing male Zucker obese (fa/fa) rats. We also examined histopathologically the safety of its high doses. Diets containing different levels of HCA (0, 10, 51, 102 and 154 mmol/kg diet) were fed to 6-week-old rats for 92 or 93 days. Each diet group was pair-fed to the 154 mmol HCA/kg diet group. Epididymal fat accumulation and histopathological changes in tissues were observed. The highest dose of HCA-containing Garcinia cambogia (154 mmol HCA/kg diet) showed significant suppression of epididymal fat accumulation in developing male Zucker obese rats, compared with the other groups. However, the diets containing 102 mmol HCA/kg diet and higher (778 and 1244 mg HCA/kg BW/d, respectively) caused potent testicular atrophy and toxicity, whereas diets containing 51 mmol HCA/kg diet (389 mg HCA/kg BW/d) or less did not. Accordingly, 51 mmol HCA/kg diet (389 mg HCA/kg BW/d) was deemed to be the no observed adverse effect level (NOAEL).

Regulation of fatty acid and cholesterol synthesis: co-operation or competition?

Fatty acids and sterols originally evolved symbiotically as structural components of cell membranes. In some respects, control of their biosynthetic pathways reflects their mutual interdependence in defining changes in the physicochemical properties of the membranes in response to the changing internal and external cellular environments. In some tissues of higher animals, however, cholesterol and fatty acids have multifunctional roles. In particular, the liver synthesizes these lipids for export as multimolecular complexes in the form of micellar bile components and lipoproteins. Intrahepatic fatty acid and cholesterol synthesis is dependent upon the balance between hepatic output of these complexes and dietary input of fat and cholesterol. Thus physiological control of these synthetic processes is often co-ordinated at both the transcriptional and post-translational levels. On the other hand, changes in flux through major metabolic pathways, particularly during physiological transitions and as a result of genetic manipulation, affects substrate availability for these pathways. Under these circumstances, regulation reflects a compensatory response to ensure that flux through the lipid pathways remains unchanged. These regulatory changes can best be interpreted in terms of a Metabolic Control Analysis approach. In summary, flux through the fatty acid and cholesterol pathways reflects (a) cellular demand for these lipids, (b) a variable availability of substrates, (c) a combination of (a) and (b).