Antidyslipidemic effects of a farnesoid X receptor antagonist in primates

FXR Antagonist FLG249 Lowers Hepatic Triacylglycerol and Serum Cholesterol Level in High-Fat Diet-Induced Obese Mice

Farnesoid X receptor (FXR) is a nuclear receptor that regulates the synthesis and enterohepatic circulation of bile acids (BAs). It also regulates lipid and carbohydrate metabolism, making FXR ligands potential therapeutic agents for systemic and/or hepatic metabolic disorders. We previously synthesized a series of FXR antagonists and showed that oral administration of FLG249 reduced the expression of several FXR target genes in the mouse ileum. Here, we investigated the effects of FLG249 on lipid metabolism in mice fed a high-fat diet (HFD). When FLG249 was administered for 4 weeks to HFD-induced obese mice, it altered the expression of genes related to BA metabolism, ceramide synthesis and fatty acid β-oxidation, improving lipid metabolism in the liver and ileum without decreasing body weight. These findings suggest that FLG249 has the potential to be a low toxicity pharmaceutical compound and likely acts as a nonsteroidal FXR antagonist to improve lipid metabolism disorders.

Antidyslipidemic potential of a novel farnesoid X receptor antagonist in a hamster model of dyslipidemia: Comparative studies of other nonstatin agents

We attempted to clarify the therapeutic capability of antagonists of the farnesoid X receptor (FXR), a nuclear receptor that regulates lipid and bile acid metabolism. Herein, we report the antidyslipidemic effects of a novel synthesized FXR antagonist, compound‐T1, utilizing a dyslipidemic hamster model. Compound‐T1 selectively inhibited chenodeoxycholic acid‐induced FXR activation (IC₅₀, 2.1 nmol·L⁻¹). A hamster model of diet‐induced hyperlipidemia was prepared to investigate the antidyslipidemic effects of compound‐T1 through comparative studies of the nonstatin lipid‐modulating agents ezetimibe, cholestyramine, and torcetrapib. In the hamster model, compound‐T1 (6 mg·kg⁻¹·day⁻¹, p.o.) increased the level of plasma high‐density lipoprotein (HDL)‐cholesterol (+22.2%) and decreased the levels of plasma non‐HDL‐cholesterol (−43.6%) and triglycerides (−31.1%). Compound‐T1 also increased hepatic cholesterol 7α‐hydroxylase expression and fecal bile acid excretion, and decreased hepatic cholesterol content. Moreover, the hamster model could reflect clinical results of other nonstatin agents. Torcetrapib especially increased large HDL particles compared with compound‐T1. Additionally, in the human hepatoma Huh‐7 cells, compound‐T1 enhanced apolipoprotein A‐I secretion at a concentration close to its IC₅₀ value for FXR. Our results indicated the usefulness of the hamster model in evaluating FXR antagonists and nonstatin agents. Notably, compound‐T1 exhibited beneficial effects on both blood non‐HDL‐cholesterol and HDL‐cholesterol, which are thought to involve enhancement of cholesterol catabolism and apolipoprotein A‐I production. These findings aid the understanding of the antidyslipidemic potential of FXR antagonists with a unique lipid and bile acid modulation.

Discovery and optimization of benzimidazole derivatives as a novel chemotype of farnesoid X receptor (FXR) antagonists

We describe here a novel chemotype with substituted benzimidazole scaffold for nonsteroidal farnesoid X receptor (FXR) antagonists starting from the identification of a screening hit, BB-4. Structure diversity in four regions A-D of BB-4 or 1 is discussed. In particular, regions A and C had an effect on an antagonism against FXR as demonstrated by the derivatives represented by 7 and 15, respectively. Thus, compound 19 arising from the combination of regions A and C underscored an important fact on antagonism against FXR, also showing the reduced small heterodimer partner and the increased cholesterol 7α-hydroxylase expression levels.

Hypolipidemic, antioxidant and anti-atherosclerogenic effect of aqueous extract leaves of Cassia. occidentalis Linn (Caesalpiniaceae) in diet-induced hypercholesterolemic rats

BACKGROUND

Hyperlipidemia and oxidative stress are major risk factors for atherosclerosis, and all three are among the most important risk factors for cardiovascular diseases. Cassia occidentalis aqueous extract has been used in African traditional medicine for the treatment of hypertension and associated cardiovascular diseases. This study was undertaken to evaluate the hypolipidemic and anti-atherosclerotic properties of the aqueous extract of the leaves of C. occidentalis in rats with hypercholesterolemia (HC). Sixty Normocholesterolemic (NC) male rats were divided into six groups (n = 10) and fed a high-cholesterol (HC) diet for 30 days (5 groups), or normal rat chow (normal control group). The plant extract was administered to animals at the increasing dose of 240, 320 and 400 mg/kg. After 4 weeks of treatment 5 rats out of 10 were sacrificed, blood samples, aorta, liver, and fresh faecal were collected and processed for biochemical tests. The experiments were conducted under the same conditions with a group of rat treated with Atorvastatin (1 mg/kg), used positive control. The effects of C. occidentalis on weight gain, water and food consumptions, levels of serum lipids and lipoprotein lipid oxidation and stress markers in blood and liver were also examined.

RESULTS

A significant body weight gain was observed in general in all the group of animals without any treatment after 4 weeks. During the treatment period, the C. occidentalis extract induced a significant increase (P < 0.01) in water consumption and food intakes. After 4 weeks of treatment with hypercholesterolemia, the body temperature and organ weights including the liver, kidney, heart and the testis did not present any significant change. The administration of C. occidentalis extract significantly (p < 0.05) prevented the elevation in TC, LDL-C, VLDL-C, hepatic and aortic TG and TC. The atherogenic, triglycerides, and lipid peroxidation (TBARS) index were also decreased in the rats treated with the plant extract. C. occidentalis favoured the performance of faecal cholesterol. It also significantly inhibited the changes and the formation of aortic atherosclerotic plaques.

CONCLUSION

This study provides evidence of hypolipidemic and antiatherosclerotic effects of C. occidentalis extract. C. occidenntalis aqueous extract reduced bad cholesterols, triglycerides and increasing good cholesterols in rats subjected to a feeding regime enriched with cholesterol. The results support the traditional use of the extract of this plant in the treatment of hypertension and diabetes.

Bile acids at the cross-roads of gut microbiome-host cardiometabolic interactions

While basic and clinical research over the last several decades has recognized a number of modifiable risk factors associated with cardiometabolic disease progression, additional and alternative biological perspectives may offer novel targets for prevention and treatment of this disease set. There is mounting preclinical and emerging clinical evidence indicating that the mass of metabolically diverse microorganisms which inhabit the human gastrointestinal tract may be implicated in initiation and modulation of cardiovascular and metabolic disease outcomes. The following review will discuss this gut microbiome-host metabolism axis and address newly proposed bile-mediated signaling pathways through which dysregulation of this homeostatic axis may influence host cardiovascular risk. With a central focus on the major nuclear and membrane-bound bile acid receptor ligands, we aim to review the putative impact of microbial bile acid modification on several major phenotypes of metabolic syndrome, from obesity to heart failure. Finally, attempting to synthesize several separate but complementary hypotheses, we will review current directions in preclinical and clinical investigation in this evolving field.

Hypolipidemic, antioxidant and anti-atherosclerogenic effects of aqueous extract of Zanthoxylum heitzii stem bark in diet-induced hypercholesterolemic rats

OBJECTIVE

To evaluate anti-dyslipidemic, antioxidant and anti-atherosclerogenic properties of this extract in diet-induced hypercholesterolemic rat, a model of metabolic syndrome-induced atherosclerosis and associated cardiovascular diseases.

METHODS

Normocholesterolemic (NC) male rats were divided into six groups (n=10) and fed a high-cholesterol (HC) diet for 30 days (5 groups), or normal rat chow (normal control group). Rats given a HC diet also received distilled water (disease control), the potent hypocholesterolemic agent with anti-atherosclerotic activity atorvastatin (2 mg/kg, positive control), or one of the three doses of Zanthoxylum heitzii stem bark aqueous extract tested (225, 300 and 375 mg/kg) concomitantly for four months. Signs of general toxicity, body temperature and weight, and water and food intake were monitored in live animals. After sacrifice, lipid profiles and oxidative stress markers were assessed in the blood and liver, aorta, and feces, and histopathological analysis of aorta was performed.

RESULTS

Plant extract prevented the elevation of aortic total cholesterol and triglycerides, and hepatic low density lipoprotein, very low density lipoprotein, and total cholesterol. Lipid peroxidation (TBARS) was decreased and aortic atherosclerotic plaque formation prevented.

CONCLUSIONS

These observations strongly suggest that stem bark aqueous extract of Zanthoxylum heitzii has anti-atherosclerogenic properties, at least partly mediated by antioxidant and hypolipidemic effects.