Pravastatin in heterozygous familial hypercholesterolemia: low-density lipoprotein (LDL) cholesterol-lowering effect and LDL receptor activity on skin fibroblastS

Statins-From Fungi to Pharmacy

Statins have been used in the treatment of hyperlipidemia, both as monotherapy and in combination therapy. Natural fermentation processes of fungi such as Monascus spp., Penicillium spp., Aspergillus terreus, and Pleurotus ostreatus have given rise to natural statins. Compactin (mevastatin), the original naturally occurring statin, is the primary biotransformation substrate in the manufacturing process of marketed drugs. Statins are classified into natural, semi-synthetic derivatives of natural statins, and synthetic ones. Synthetic statins differ from natural statins in their structural composition, with the only common feature being the HMG-CoA-like moiety responsible for suppressing HMG-CoA reductase. Statins do not differ significantly regarding their pleiotropic and adverse effects, but their characteristics depend on their pharmacokinetic parameters and chemical properties. This paper focuses on describing the processes of obtaining natural statins, detailing the pharmacokinetics of available statins, divided into natural and synthetic, and indicating their pleiotropic effects.

High-fat diet-induced dopaminergic dysregulation induces REM sleep fragmentation and ADHD-like behaviors

Consumption of a high-fat diet (HFD) has been associated with reduced wakefulness and various behavioral deficits, including anxiety, depression, and anhedonia. The dopaminergic system, which plays a crucial role in sleep and ADHD, is known to be vulnerable to chronic HFD. However, the association between HFD-induced behavioral and molecular changes remains unclear. Therefore, we investigated the effects of a HFD on the dopaminergic system and its association with behavioral deficits in male mice. The mice were divided into normal diet and HFD groups and were analyzed for sleep patterns, behavior tests, and transcription levels of dopamine-related genes in the brain. The HFD group showed decreased wakefulness, increased REM sleep with fragmented patterns, decreased time spent in the center zone of the open field test, shorter immobile time in the tail suspension test, impaired visuospatial memory, and reduced sucrose preference. Additionally, the HFD group had decreased mRNA levels of D1R, COMT, and DAT in the nucleus accumbens, which negatively correlated with REM sleep proportion and REM sleep bout count. The results suggest that HFD-induced behavioral deficits were resemblance to ADHD-like behavioral phenotypes and disturbs REM sleep by dysregulating the dopaminergic system.

A Review of Progress on Targeting LDL Receptor-Dependent and -Independent Pathways for the Treatment of Hypercholesterolemia, a Major Risk Factor of ASCVD

Since the discovery of the LDL receptor in 1973 by Brown and Goldstein as a causative protein in hypercholesterolemia, tremendous amounts of effort have gone into finding ways to manage high LDL cholesterol in familial hypercholesterolemic (HoFH and HeFH) individuals with loss-of-function mutations in the LDL receptor (LDLR) gene. Statins proved to be the first blockbuster drug, helping both HoFH and HeFH individuals by inhibiting the cholesterol synthesis pathway rate-limiting enzyme HMG-CoA reductase and inducing the LDL receptor. However, statins could not achieve the therapeutic goal of LDL. Other therapies targeting LDLR include PCSK9, which lowers LDLR by promoting LDLR degradation. Inducible degrader of LDLR (IDOL) also controls the LDLR protein, but an IDOL-based therapy is yet to be developed. Among the LDLR-independent pathways, such as angiopoietin-like 3 (ANGPTL3), apolipoprotein (apo) B, apoC-III and CETP, only ANGPTL3 offers the advantage of treating both HoFH and HeFH patients and showing relatively better preclinical and clinical efficacy in animal models and hypercholesterolemic individuals, respectively. While loss-of-LDLR-function mutations have been known for decades, gain-of-LDLR-function mutations have recently been identified in some individuals. The new information on gain of LDLR function, together with CRISPR-Cas9 genome/base editing technology to target LDLR and ANGPTL3, offers promise to HoFH and HeFH individuals who are at a higher risk of developing atherosclerotic cardiovascular disease (ASCVD).

Multiparametric platform for profiling lipid trafficking in human leukocytes

Systematic insight into cellular dysfunction can improve understanding of disease etiology, risk assessment, and patient stratification. We present a multiparametric high-content imaging platform enabling quantification of low-density lipoprotein (LDL) uptake and lipid storage in cytoplasmic droplets of primary leukocyte subpopulations. We validate this platform with samples from 65 individuals with variable blood LDL-cholesterol (LDL-c) levels, including familial hypercholesterolemia (FH) and non-FH subjects. We integrate lipid storage data into another readout parameter, lipid mobilization, measuring the efficiency with which cells deplete lipid reservoirs. Lipid mobilization correlates positively with LDL uptake and negatively with hypercholesterolemia and age, improving differentiation of individuals with normal and elevated LDL-c. Moreover, combination of cell-based readouts with a polygenic risk score for LDL-c explains hypercholesterolemia better than the genetic risk score alone. This platform provides functional insights into cellular lipid trafficking and has broad possible applications in dissecting the cellular basis of metabolic disorders.

Familial hypercholesterolemia and response to statin therapy according to LDLR genetic background

Familial hypercholesterolemia is an autosomal dominant disease defined at the molecular level mainly by the presence of mutations in the low-density lipoprotein receptor gene and is characterized by elevated low-density lipoprotein cholesterol, tendon xanthomas and increased risk of early cardiovascular disease. The type of mutation in the low-density lipoprotein receptor gene has been associated with different phenotype expression and response to statins. Several studies have been undertaken to assess the efficacy of statins and evaluate the influence of mutations on the response to treatment with statins. Not all patients respond to statin therapy with a reduction in cardiovascular disease. In this review paper, we will discuss the results available to date that correlate the low-density lipoprotein receptor genotype to the response to statins, and the interest in developing diagnostic systems which will allow identification of patients at increased risk of adverse drug reactions or patients in which a therapeutic effect is lacking.

Familial hypercholesterolemia--improving treatment and meeting guidelines

Familial hypercholesterolemia (FH) is a common, inherited disorder that affects around one in 500 individuals in the heterozygous form. By the year 2001, more people in the US had FH than were infected by the human immunodeficiency virus. The disease is caused by mutations within the low-density lipoprotein (LDL) receptor gene. FH is associated with elevated plasma LDL-cholesterol (LDL-C) levels, xanthomatosis, early onset of atherosclerosis and premature cardiac death. Patients with heterozygous FH commonly have plasma LDL-C levels that are two-fold higher than normal, while homozygotes have four- to five-fold elevations in plasma LDL-C. Although FH patients have a high risk of developing premature coronary heart disease (CHD), they remain underdiagnosed and undertreated. Early detection of FH is critical to prolonging the life of these patients. Once identified, patients with heterozygous FH can be placed on a diet and drug management program. As the most efficacious and well-tolerated agents, hydroxy methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are usually the drugs of first choice; bile acid sequestrants, niacin, and occasionally fibrates may be used as supplemental agents. Statins may also provide a realistic option for the treatment of some FH homozygotes with genes that produce partially functional LDL receptors. However, a number of patients are still failing to reach treatment guidelines even with the most effective of the currently available statins. The development of new more efficacious statins or the use of new combination therapies such as statins with the cholesterol absorption inhibitor, ezetimibe may help to reduce the current problem of undertreatment in FH patients.

Flow cytometric assessment of effects of fluvastatin on low-density lipoprotein receptor activity in stimulated T-lymphocytes from patients with heterozygous familial hypercholesterolemia

To test the effects of fluvastatin on low-density lipoprotein (LDL) receptor activity in patients with heterozygous familial hypercholesterolemia, the authors measured LDL receptor activity in stimulated T-lymphocytes prepared from 34 patients before and after treatment with 40 mg fluvastatin daily for 12 weeks. Maximally induced pretreatment LDL receptor activities did not correlate with pretreatment plasma cholesterol levels or with changes in plasma cholesterol levels during treatment, and there were no significant changes in LDL receptor activity during treatment. Barring methodological problems, two explanations are possible. Insofar that LDL receptor activity in lymphocytes reflects LDL receptor activity in the liver, the results suggest that the primary response to treatment with fluvastatin in heterozygous familial hypercholesterolemia (FH) patients is not enhanced LDL receptor activity. Alternatively, fluvastatin increases LDL receptor activity in hepatocytes but has little effect on receptor-dependent lipoprotein catabolism in extrahepatic tissues in vivo.

Metabolism and drug interactions of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in transplant patients: are the statins mechanistically similar?

3-Hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.88) inhibitors are the most effective drugs to lower cholesterol in transplant patients. However, immunosuppressants and several other drugs used after organ transplantation are cytochrome P4503A (CYP3A, EC 1.14.14.1) substrates. Pharmacokinetic interaction with some of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, specifically lovastatin and simvastatin, leads to an increased incidence of muscle skeletal toxicity in transplant patients. It is our objective to review the role of drug metabolism and drug interactions of lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, and cerivastatin. In the treatment of transplant patients, from a drug interaction perspective, pravastatin, which is not significantly metabolized by CYP enzymes, and fluvastatin, presumably a CYP2C9 substrate, compare favorably with the other statins for which the major metabolic pathways are catalyzed by CYP3A.

Low-density lipoprotein receptor genotype-dependent response to cholesterol lowering by combined pravastatin and cholestyramine in familial hypercholesterolemia

We compared the effects of cholesterol-lowering therapy on 2 patient groups genetically defined as heterozygous for familial hypercholesterolemia (FH), 5 with a deletion of exon 15 (FH(Tonami-1)), and 7 with a point mutation at codon 664 (FH(Kanazawa-2)). There were significant differences in both serum and low-density lipoprotein cholesterol reductions between the 2 groups after combination therapy with pravastatin and cholestyramine, and the overall effect of genotype on serial changes in both was significant.

Cost-effectiveness of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor therapy in the managed care era

More than $100 billion is spent in the United States each year on cardiovascular disease, primarily for hospitalizations and revascularization procedures. This is more than for any other disease state. As the clinical practice of medicine shifts from the paradigm of private practice to the managed care environment, cost-effectiveness is becoming increasingly important. A primary measure in analyzing cost-effectiveness is the cost-effectiveness ratio, or the dollar cost per unit of improvement for a given expenditure. This measure allows healthcare planners to compare completely different interventions. With approximately 52 million adult U.S. citizens having elevated low-density lipoprotein (LDL) cholesterol levels, lipid-lowering therapy---with diet or 3-hydroxy-3methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors---is an important consideration for primary care physicians and managed care providers. The National Health and Nutrition Examination Survey (NHANES) III indicates that 75-88% of adults who have coronary artery disease (CAD) risk factors or CAD require only a moderate (20--30%) reduction in LDL cholesterol levels to reach National Cholesterol Education Program goals. The clinical literature shows that all 4 of the currently available HMG-CoA reductase inhibitors can provide appropriate, moderate LDL cholesterol reductions within their recommended dosage ranges. For the majority of patients who need a 20--30% reduction in LDL cholesterol, fluvastatin 20 or 40 mg once daily provides the most cost-effective HMG-CoA therapy, expressed as cost of therapy per 1% LDL cholesterol reduction. For patients who need a >30% LDL cholesterol reduction, a high-dose HMG-CoA reductase inhibitor (e.g., simvastatin 20 or 40 mg/day) or a combination of a lower-dose HMG-CoA reductase inhibitor and a bile acid resin is the preferred initial therapy. Although a true cost-effectiveness analysis would incorporate morbidity and mortality data from clinical trials, analysis using intermediate endpoints, such as LDL cholesterol reduction, suggests that fluvastatin is the preferred initial HMG-CoA reductase inhibitor for the treatment of moderate hyperlipidemia.

Meeting national cholesterol education goals in clinical practice--a comparison of lovastatin and fluvastatin in primary prevention

The available clinical data for 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors demonstrate their efficacy and safety in treating hypercholesterolemia and improving long-term morbidity and mortality related to coronary artery disease. Comparative studies among agents in this class support the general perception that, at the most commonly prescribed doses, all these drugs reduce low-density lipoprotein (LDL) cholesterol levels by about 20-30%. The primary measure of efficacy in the current study was the percentage of patients achieving goal levels for LDL cholesterol of < 160 mg/dL, as proposed by the National Cholesterol Education Program (NCEP). This study compares the most widely prescribed agent in this class, lovastatin, with the newest agent, fluvastatin. Patients enrolled had previously been satisfactorily treated with lovastatin 20 mg every evening. Following a placebo washout period, patients were randomized to receive lovastatin 20 mg with the evening meal (69 patients) or fluvastatin 20 mg at bedtime (68 patients) for 4 weeks of open-label therapy. In a second 4-week period, patients on lovastatin continued on the initial dosage while patients receiving fluvastatin had their daily dosage increased to 40 mg at bedtime to evaluate the range of efficacy from 20-40 mg/day. In both treatment arms, the majority of patients achieved the goal lipid level. Approximately 85% of patients on fluvastatin 20 mg and 90% of patients on lovastatin 20 mg achieved the goal within 4 weeks. This small difference was not statistically significant. Increasing the dosage to 40 mg at bedtime in the fluvastatin arm produced goal LDL cholesterol levels in about 90% of patients. Both agents were well tolerated; no patients discontinued therapy because of adverse events.

Exogenous CoQ10 preserves plasma ubiquinone levels in patients treated with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

Ubiquinone is a carrier of the mitochondrial respiratory chain which regulates oxidative phosphorylation: it also acts as a membrane stabilizer preventing lipid peroxidation. In man the quinone ring originates from tyrosine, while the formation of the polyisoprenoid lateral chain starts from acetyl CoA and proceeds through mevalonate and isopentenylpyrophosphate; this biosynthetic pathway is the same as the cholesterol one. We therefore performed this study to evaluate whether statins (hypocholesterolemic drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase) modify blood levels of ubiquinone. Thirty unrelated outpatients with primary hypercholesterolemia (IIa phenotype) were treated with 20 mg of simvastatin for a 3-month period (group S) or with 20 mg of simvastatin plus 100 mg CoQ10 (group US). The following parameters were evaluated at time 0, and at 45 and 90 days: total plasma cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglycerides, Apo A1, Apo B and CoQ10 in plasma and in platelets. In the S group, there was a marked decrease in total cholesterol low-density lipoprotein-cholesterol and in plasma CoQ10 levels from 1.08 mg/dl to 0.80 mg/dl. In contrast, in the US group we observed a significant increase of plasma CoQ10 (from 1.20 to 1.48 mg/dl) while the hypocholesterolemic effect was similar to that observed in the S group. Platelet CoQ10 also decreased in the S group (from 104 to 90 ng/mg) and increased in the US group (from 95 to 145 ng/mg).(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue selectivity of hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitors

Hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitors are a class of lipid-lowering medications, with a major activity on plasma cholesterol levels, now enjoying a vast popularity among physicians and patients. These drugs, affecting a very early and key step of sterol biosynthesis, differ to a large extent in their physicochemical properties, tissue distribution and side effects in animals, possibly in humans. Some of these agents (namely lovastatin and simvastatin) are strikingly lipophilic and require enzymatic conversion from the lactone to the open-ring forms, whereas pravastatin, active per se, is hydrophilic. Liver uptake of pravastatin is regulated by a carrier-mediated mechanism. Other HMG CoA reductase inhibitors have been designed, with the objective of obtaining high levels of hepato-selectivity. Evaluation of available data in terms of potential advantages in tissue, namely liver selectivity, of HMG CoA reductase inhibitors, suggests, that, indeed, altered sterol biosynthesis in a number of tissues may potentially result in the appearance of significant side effects. While there is no clear-cut relationship between tissue selectivity and lipophilicity, the presence of this latter feature seems, in general, to dictate a lesser absorption to peripheral tissues vs the liver. At present, the toxicological profile of major HMG CoA reductase inhibitors appears safe; it is, however, possible that in selected patient groups liver selectivity may offer a considerable therapeutic advantage.

Decreased in vitro oxidizability of low-density lipoprotein in hypercholesterolaemic patients treated with 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors

We studied the effects of the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors simvastatin and pravastatin on the in vitro susceptibility of low-density lipoprotein (LDL) to oxidation. Twenty-three hypercholesterolaemic patients (mean serum cholesterol 9.7 mmol l-1) were treated with increasing doses of either simvastatin or pravastatin for 18 weeks. No significant differences in effect on lipid levels between the two drugs were found. Treatment resulted in lowering of total cholesterol and LDL-cholesterol by maximally 30% and 34%, respectively. Chemical composition analysis showed that LDL particles contained relatively more protein and less free cholesterol and cholesteryl-ester after treatment. The LDL cholesterol/protein ratio decreased from 1.24 +/- 0.21 to 0.97 +/- 0.23 (n = 20). By continuous monitoring of in vitro oxidation it appeared that LDL was less susceptible to oxidation after drug treatment. Maximal rate of diene production was significantly decreased from 19.7 +/- 3.1 to 18.5 +/- 3.3 nmol min-1 mg-1 LDL; total diene production decreased significantly from 420.3 +/- 67.6 to 380.5 +/- 49.1 nmol mg-1 LDL; the lag time was unchanged throughout the study. These studies show that HMG-CoA reductase inhibitors reduce the oxidizability of LDL by altering its composition.