[Lipid-lowering drugs]

Mechanism of Action of Shenerjiangzhi Formulation on Hyperlipidemia Induced by Consumption of a High-Fat Diet in Rats Using Network Pharmacology and Analyses of the Gut Microbiota

Shenerjiangzhi formulation (SEJZ) is a new traditional Chinese medicine formulation (patent number: CN110680850A). SEJZ contains Eleutherococcus senticosus (Rupr. and Maxim.), Maxim (Araliaceae; E. senticosus radix and rhizome), Lonicera japonica Thunb (Caprifoliaceae; Lonicera japonica branch, stem), Crataegus pinnatifida Bunge (Rosaceae; Crataegus pinnatifida fruit), and Auricularia auricula. SEJZ has been designed to treat hyperlipidemia. Despite the therapeutic benefits of SEJZ, its underlying mechanism of action is not known. We explored the efficacy of SEJZ against hyperlipidemia by integrating network pharmacology and 16S rRNA gene sequencing and elucidated its mechanism of action. First, SEJZ targets were found through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and from the literature. Hyperlipidemia-related therapeutic targets were obtained from GeneCards, Online Mendelian Inheritance in Man, and DrugBank databases. Then, Search Tool for the Retrieval of Interacting Genes/Proteins and Cytoscape were applied for the analyses and construction of a protein–protein interaction (PPI) network. The Kyoto Encyclopedia of Genes and Genomes database was employed to identify signaling pathways that were enriched. Second, the therapeutic effects of SEJZ against hyperlipidemia induced by consumption of a high-fat diet in rats were evaluated by measuring body weight changes and biochemical tests. SEJZ treatment was found to alleviate obesity and hyperlipidemia in rats. Finally, 16S rRNA gene sequencing showed that SEJZ could significantly increase the abundance of short-chain fatty acid-producing bacteria, restore the intestinal barrier, and maintain intestinal-flora homeostasis. Using PICRUSt2, six metabolic pathways were found to be consistent with the results of network pharmacology: “African trypanosomiasis”, “amoebiasis”, “arginine and proline metabolism”, “calcium signaling pathway”, “NOD-like receptor signaling pathway”, and “tryptophan metabolism”. These pathways might represent how SEJZ works against hyperlipidemia. Moreover, the “African trypanosomiasis pathway” had the highest association with core genes. These results aid understanding of how SEJZ works against dyslipidemia and provide a reference for further studies.

Synthesis and structure–activity relationship studies on a novel series of naphthylidinoylureas as inhibitors of acyl-CoA:cholesterol O -acyltransferase (ACAT)

The synthesis and structure-activity relationships of N-phenyl-N'-[3-(4-phenylnaphthylidinoyl)]urea derivatives 3 as a novel structural class of potent ACAT inhibitors is described. A 3-methoxy group substituted on the naphthylidinone 4-phenyl ring, together with a 1-N-(n)butyl substitution, SM-32504 (3m), gave a potent ACAT inhibitor, in vitro, respectively. The most potent compound, SM-32504 (3m), decreased the serum cholesterol level significantly in a high fat and high cholesterol-fed mouse model.

Pharmacotherapy for dyslipidaemia--current therapies and future agents

Current lipid-altering agents that lower low density lipoprotein cholesterol (LDL-C) primarily through increased hepatic LDL receptor activity include statins, bile acid sequestrants/resins and cholesterol absorption inhibitors such as ezetimibe, plant stanols/sterols, polyphenols, as well as nutraceuticals such as oat bran, psyllium and soy proteins; those currently in development include newer statins, phytostanol analogues, squalene synthase inhibitors, bile acid transport inhibitors and SREBP cleavage-activating protein (SCAP) activating ligands. Other current agents that affect lipid metabolism include nicotinic acid (niacin), acipimox, high-dose fish oils, antioxidants and policosanol, whilst those in development include microsomal triglyceride transfer protein (MTP) inhibitors, acylcoenzyme A: cholesterol acyltransferase (ACAT) inhibitors, gemcabene, lifibrol, pantothenic acid analogues, nicotinic acid-receptor agonists, anti-inflammatory agents (such as Lp-PLA(2) antagonists and AGI1067) and functional oils. Current agents that affect nuclear receptors include PPAR-alpha and -gamma agonists, while in development are newer PPAR-alpha, -gamma and -delta agonists, as well as dual PPAR-alpha/gamma and 'pan' PPAR-alpha/gamma/delta agonists. Liver X receptor (LXR), farnesoid X receptor (FXR) and sterol-regulatory element binding protein (SREBP) are also nuclear receptor targets of investigational agents. Agents in development also may affect high density lipoprotein cholesterol (HDL-C) blood levels or flux and include cholesteryl ester transfer protein (CETP) inhibitors (such as torcetrapib), CETP vaccines, various HDL 'therapies' and upregulators of ATP-binding cassette transporter (ABC) A1, lecithin cholesterol acyltransferase (LCAT) and scavenger receptor class B Type 1 (SRB1), as well as synthetic apolipoprotein (Apo)E-related peptides. Fixed-dose combination lipid-altering drugs are currently available such as extended-release niacin/lovastatin, whilst atorvastatin/amlodipine, ezetimibe/simvastatin, atorvastatin/CETP inhibitor, statin/PPAR agonist, extended-release niacin/simvastatin and pravastatin/aspirin are under development. Finally, current and future lipid-altering drugs may include anti-obesity agents which could favourably affect lipid levels.

Existing and investigational combination drug therapy for high-density lipoprotein cholesterol

For the past 3 to 4 decades, clinical outcomes trials have shown that drugs that favorably alter serum lipid levels reduce the risk of coronary artery disease (CAD) events. However, despite these successes, the reduction in serum low-density lipoprotein (LDL) cholesterol levels with monotherapy lipid-altering drugs does not "cure" CAD to the same degree that antibiotics "cure" many infections, nor do they "prevent" CAD in the same way that childhood immunizations "prevent" the onset of such conditions as measles, mumps, and rubella. Clinical outcome trials of monotherapy lipid-altering drugs have demonstrated a reduction in the relative risk of CAD in only a minority of patients. Thus, although safe and very effective in lowering serum LDL cholesterol levels, drugs that predominantly lower cholesterol do not "cure" atherosclerotic disease, nor have they been shown to "prevent" most CAD events in numerous clinical outcome trials. The reason for the suboptimal CAD outcomes benefits of monotherapy lipid-altering drugs is likely because atherosclerosis is a complex pathologic process with many important risk factors involved in the initiation and progression of atherosclerotic lesions and involved in the onset of the CAD event itself. An elevated serum LDL cholesterol level is an important CAD risk factor, but it is not the only lipid risk factor. A decreased serum high-density lipoprotein (HDL) cholesterol level is another important risk factor for CAD. Combination therapy through existing drugs (or possibly, in the future, through investigational lipid-altering drugs) may not only improve LDL cholesterol but also improve serum HDL cholesterol levels. This more global, multidimensional approach to lipid-altering drug treatment may provide the best chance to prevent CAD.

Cholesterol absorption inhibitors for the treatment of hypercholesterolaemia

The benefits of lipid lowering therapy on coronary heart disease have been clearly established in many clinical trials on primary and secondary prevention. Despite the availability of potent lipid lowering drugs, many patients do not reach the current treatment goals. This paper reviews new therapeutic approaches in lipid lowering drugs focusing on compounds which lower cholesterol absorption. The role of plant sterols and stanols, new acyl-CoA:cholesterol O-acyl transferase (ACAT) inhibitors, microsomal triglyceride transfer protein (MTP) inhibitors, and ezetimibe are summarised. Although the lipid lowering effect of plant sterols and plant stanols is only moderate, their use as functional foods is beneficial for patients with mild hypercholesterolaemia and is able to enhance the lipid lowering effect of HMG-CoA reductase inhibitors (statins). The role of ACAT inhibitors that might also inhibit cholesterol absorption remains unclear. Avasimibe, the first oral bioavailable ACAT inhibitor, has entered phase III trials. However, the presently available data in humans do not indicate a clear clinical benefit. The role of MTP inhibitors, which exhibit remarkable effects on all plasma lipids, also remains unclear, as safety concerns must first be addressed. Ezetimibe, the first available 2-azetidinone, succeeded in phase III trials showing remarkable effects in inhibition of cholesterol absorption as well as cholesterol lowering. The synergistic effect of co-administration of ezetimibe with statins seemingly offers a new approach in reaching the therapeutic goals.