Clinical pharmacokinetics of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors

Statins: Beneficial Effects in Treatment of COVID-19

The recent viral disease COVID-19 has attracted much attention. The disease is caused by SARS-CoV-19 virus which has different variants and mutations. The mortality rate of SARS-CoV-19 is high and efforts to establish proper therapeutic solutions are still ongoing. Inflammation plays a substantial part in the pathogenesis of this disease causing mainly lung tissue destruction and eventually death. Therefore, anti-inflammatory drugs or treatments that can inhibit inflammation are important options. Various inflammatory pathways such as nuclear factor Kappa B (NF-κB), signal transducer of activators of transcription (STAT), nod-like receptor family protein 3 (NLRP), toll-like receptors (TLRs), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) pathways and mediators, such as interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α), and interferon-γ (INF-γ), cause cell apoptosis, reduce respiratory capacity and oxygen supply, eventually inducing respiratory system failure and death. Statins are well known for controlling hypercholesterolemia and may serve to treat COVID-19 due to their pleiotropic effects among which are anti-inflammatory in nature. In this chapter, the anti-inflammatory effects of statins and their possible beneficial effects in COVID-19 treatment are discussed. Data were collected from experimental and clinical studies in English (1998-October 2022) from Google Scholar, PubMed, Scopus, and the Cochrane Library.

Management of familial hypercholesterolemia in pregnancy

PURPOSE OF REVIEW

To highlight quandaries and review options for the management of familial hypercholesterolemia (FH) during pregnancy.

RECENT FINDINGS

Women with FH face barriers to effective care and consequently face significant disease related long term morbidity and mortality.Pregnancy includes major maternal physiological changes resulting in exacerbation of maternal hypercholesterolemia compounded by the current practice of cessation or reduction in the dose of lipid-lowering therapy during pregnancy and lactation that may impact short and long term cardiac morbidity and mortality. Although lipoprotein apheresis is the treatment of choice for high- risk FH patients, reassuring safety evidence for the use of statins during pregnancy is mounting rapidly. However, it will be some time before subtle effects on the development of the offspring can be definitively excluded. Women with homozygous FH or with an established atherosclerotic vessel or aortic disease should be offered therapy with statins during pregnancy if lipoprotein apheresis is not readily available. Pregnancy outcomes tend to be favourable in women with FH. We have reviewed the currently available evidence regarding the risks and benefits of treatment options for FH during pregnancy.

The effect of statins on semen parameters in patients with hypercholesterolemia: A systematic review

BACKGROUND

Statins constitute the mainstay of treatment in patients with hypercholesterolemia. However, their effect on semen parameters is unknown.

OBJECTIVE

This study aimed to systematically review the best available evidence regarding the effect of statins on ejaculate volume and sperm concentration, motility, morphology, or vitality.

MATERIALS/METHODS

A comprehensive search was conducted in PubMed, CENTRAL and Scopus databases up to January 10, 2021. Either randomized-controlled trials or prospective cohorts, conducted in males with hypercholesterolemia, were included.

RESULTS

Four studies, published between 1992 and 2014, were eligible. The number of participants ranged from 8 to 120 (n = 161). Study duration ranged from 14 to 48 weeks. The type and dose of statin used were pravastatin 20-80 mg/day and simvastatin 20-40 mg/day. With regard to ejaculate volume (n = 3) and sperm concentration (n = 4), no effect was shown with either pravastatin or simvastatin. Regarding sperm motility, either an increase (n = 2; pravastatin, simvastatin), decrease (n = 1; pravastatin), or no effect (n = 1; pravastatin, simvastatin) was found. With respect to sperm morphology, either a decrease (n = 2; pravastatin, simvastatin) or no effect (n = 2; pravastatin, simvastatin) was shown. Concerning sperm vitality, a single study showed a decrease with simvastatin. Because of the high heterogeneity of the populations studied and the limited number of studies, a meta-analysis was not performed.

CONCLUSION

This is the first systematic review on the effect of statins on semen parameters. As there is no evidence for such a detrimental effect, no specific approach has to be suggested regarding the preservation of reproductive function in men with hypercholesterolemia.

Protocol for systematic review and meta-analysis: impact of statins as immune-modulatory agents on inflammatory markers in adults with chronic diseases

INTRODUCTION

Statins, also known as 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, are lipid-lowering agents that are central in preventing or reducing the complications of atherosclerotic cardiovascular disease. Because statins have anti-inflammatory properties, there is considerable interest in their therapeutic potential in other chronic inflammatory conditions. We aim to identify the statin with the greatest ability to reduce systemic inflammation, independent of the underlying disease entity.

METHODS AND ANALYSIS

We aim to conduct a comprehensive search of published and peer-reviewed randomised controlled clinical trials, with at least one intervention arm of a Food & Drug Administration-licensed or European Medicines Agency-licensed statin and a minimum treatment duration of 12 weeks. Our objective is to investigate the effect of statins (atorvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin) on lipid profile, particularly, cholesterol low-density lipoprotein and inflammation markers such as high-sensitive C reactive protein (hsCRP), CRP, tumour necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, soluble cluster of differentiation 14 (sCD14) or sCD16 in adults, published in the last 20 years (between January 1999 and December 2019). We aim to identify the most potent statin to reduce systemic inflammation and optimal dosing. The following databases will be searched: Medline, Scopus, Web of Science and Cochrane Library of Systematic Reviews. The risk of bias of included studies will be assessed by Cochrane Risk of Bias Tool and Quality Assessment Tool for Quantitative Studies. The quality of studies will be assessed, to show uncertainty, by the Jadad Score. If sufficient evidence is identified, a meta-analysis will be conducted with risk ratios or ORs with 95% CIs in addition to mean differences.

ETHICS AND DISSEMINATION

Ethics approval is not required as no primary data will be collected. Results will be presented at conferences and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020169919.

Spray-Dried Amorphous Solid Dispersions of Atorvastatin Calcium for Improved Supersaturation and Oral Bioavailability

Over the past few decades, the amorphous solid dispersions (ASDs) technique has emerged as a promising strategy to enhance the in vitro/in vivo characteristic of hydrophobic drugs. The low aqueous solubility and poor bioavailability of atorvastatin calcium (ATO), a lipid-lowering drug, present challenges for effective drug delivery. The objective of this work was to improve the aqueous solubility, in vitro dissolution, and oral absorption of ATO with amorphous solid dispersion technique prepared by spray-drying method. The optimized ternary formulation comprising of ATO; hydroxypropyl methylcellulose (HPMC), as a hydrophilic polymer; and sodium lauryl sulfate (SLS), as a surfactant, at a weight ratio of 1/1/0.1, showed significant improvement in aqueous solubility by ~18-fold compared to that of the free drug, and a cumulative release of 94.09% compared to a release of 59.32% of the free drug. Further, physicochemical studies via scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction revealed a change from the crystalline state of the free drug to its amorphous state in the ASD. Pharmacokinetic analysis in rats demonstrated 1.68- and 2.39-fold increments in AUC and Cmax, respectively, in the ASD over the free drug. Altogether, hydrophilic carrier-based ASDs prepared by the spray-drying technique represent a promising strategy to improve the biopharmaceutical performance of poorly soluble drugs.

Preparation, characterization, and in vitro/vivo evaluation of polymer-assisting formulation of atorvastatin calcium based on solid dispersion technique

Due to low solubility and bioavailability, atorvastatin calcium is confronted with challenge in conceiving appropriate formulation. Solid dispersion of atorvastatin calcium was prepared through the solvent evaporation method, with Poloxamer 188 as hydrophilic carriers. This formulation was then characterized by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction and fourier transform infrared spectroscopy. Moreover, all these studies suggested the conversion of crystalline atorvastatin calcium. In addition, the drug solubility studies as well as dissolution rates compared with bulk drug and market tablets Lipitor were also examined. Furthermore, the study investigated the pharmacokinetics after oral administration of Lipitor and solid dispersion. And the AUC_0–8 h and C_max increased after taking ATC-P188 solid dispersion orally compared with that of Lipitor. All these could be demonstrated that ATC-P188 solid dispersions would be prospective means for enhancing higher oral bioavailability of ATC.

High-Dose Metformin May Increase the Concentration of Atorvastatin in the Liver by Inhibition of Multidrug Resistance-Associated Protein 2

In this study, we evaluated the effect of coadministered metformin on the biliary excretion and liver concentration of atorvastatin. To investigate the inhibitory effect of metformin on biliary efflux transporters, the transport of atorvastatin in MDCKII-MDR1, BCRP, and MRP2 was evaluated. The effects of metformin on the steady state liver concentration and biliary excretion of atorvastatin and 2-hydroxyatorvastatin were evaluated in SDR and Mrp2-deficient EHBR. Metformin did not inhibit the transport of atorvastatin via BCRP and MDR1. However, metformin significantly inhibited the transport of atorvastatin and 2-hydroxyatorvastatin via MRP2 (apparent IC₅₀ = 12 and 2 μM). Coadministered metformin significantly increased the K_p,liver and C_liver (1.7- and 1.6-fold) and decreased the biliary clearance of atorvastatin (2.7-fold) in SDR, but it did not affect the plasma concentration and total clearance of atorvastatin. Similar effects by metformin were observed for 2-hydroxyatorvastatin. In addition, coadministered metformin did not have any effect in EHBR. Therefore, coadministered metformin increases the liver concentration of atorvastatin via inhibition of the Mrp2 in rats, without affecting the plasma concentration. This "silent interaction" by metformin in atorvastatin and metformin combination therapy may be related to the unnoticeable pharmacological synergism or unpredicted side effects of atorvastatin in the liver.

A randomized trial of direct pulp capping in primary molars using MTA compared to 3Mixtatin: a novel pulp capping biomaterial

OBJECTIVE

This study aimed to examine the efficacy of 3Mixtatin (a combination of simvastatin and 3Mix antibiotic) as a novel pulp capping biomaterial in DPC of human primary molars.

METHODS

In this randomized clinical trial, 160 primary molars from 83 healthy children aged 3-6 years were randomly allocated into four groups. Small traumatic non-caries pulpal exposures were treated by DPC using simvastatin, 3Mix, 3Mixtatin, or MTA. Capping materials were covered with hard-setting zinc oxide eugenol (ZOE) cement, and then, teeth were restored with amalgam. Clinical and radiographic examinations were conducted at 2, 6, and 12 months after treatment. The data were compared using chi-square test at a significance level of 0.05.

RESULTS

One hundred and twenty-nine teeth were available for follow-up study. By the end of 12 months, the overall success rates were 93.8% in MTA, 91.9% in 3Mixtatin, 62.5% in 3Mix, and 57.1% in simvastatingroups. No statistically significant difference was found between the outcomes of MTA and 3Mixtatin groups (P > 0.05). 3Mixtatin had statistically superior results compared to 3Mix and simvastatin (P < 0.01).

CONCLUSION

Radiographic and clinical outcomes in 3Mixtatin group could suggest it as an acceptable alternative in DPC of primary molar teeth.

Mechanism of Drug-Drug Interactions Between Warfarin and Statins

The anticoagulant drug warfarin and the lipid-lowering statin drugs are commonly co-administered to patients with cardiovascular diseases. Clinically significant drug-drug interactions (DDIs) between these drugs have been recognized through case studies for many years, but the biochemical mechanisms causing these interactions have not been explained fully. Previous theories include kinetic alterations in cytochrome P-450-mediated drug metabolism or disturbances of drug-protein binding, leading to anticoagulant activity of warfarin; however, neither the enantioselective effects on warfarin metabolism nor the potential disruption of drug transporter function have been well investigated. This study investigated the etiology of the DDIs between warfarin and statins. Liquid chromatography-mass spectrometry methods were developed and validated to quantify racemic warfarin, 6 of its hydroxylated metabolites, and pure enantiomers of warfarin; these methods were applied to study the role of different absorption, distribution, metabolism, and excretion properties, leading to DDIs. Plasma protein binding displacement of warfarin was performed in the presence of statins using equilibrium dialysis method. Substrate kinetics of warfarin and pure enantiomers were performed with human liver microsomes to determine the kinetic parameters (Km and Vmax) for the formation of all 6 hydroxywarfarin metabolites, inhibition of warfarin metabolism in the presence of statins, was determined. Uptake transport studies of warfarin were performed using overexpressing HEK cell lines and efflux transport using human adenocarcinoma colonic cell line cells. Fluvastatin significantly displaced plasma protein binding of warfarin and pure enantiomers; no other statin resulted in significant displacement of warfarin. All the statins that inhibited the formation of 10-hydroxywarfarin, atorvastatin, pitavastatin, and simvastatin were highly potent compared to other statins; in contrast, only fluvastatin was found to be a potent inhibitor of formation of 7-hydroxy warfarin. Uptake and efflux drug transporters do not play any role in these DDIs. The results showed that DDIs between warfarin and statins are primarily caused by cytochrome P-450 inhibition.

Statin Concentrations Below the Minimum Inhibitory Concentration Attenuate the Virulence of Rhizopus oryzae

BACKGROUND

Mucormycosis is a destructive invasive mold infection afflicting patients with diabetes and hematologic malignancies. Patients with diabetes are often treated with statins, which have been shown to have antifungal properties. We sought to examine the effects of statins on Rhizopus oryzae, a common cause of mucormycosis.

METHODS

Clinical strains of R. oryzae were exposed to lovastatin, atorvastatin, and simvastatin and the minimum inhibitory concentrations (MICs) were determined. R. oryzae germination, DNA fragmentation, susceptibility to oxidative stress, and ability to damage endothelial cells were assessed. We further investigated the impact of exposure to lovastatin on the virulence of R. oryzae

RESULTS

All statins had MICs of >64 µg/mL against R. oryzae Exposure of R. oryzae to statins decreased germling formation, induced DNA fragmentation, and attenuated damage to endothelial cells independently of the expression of GRP78 and CotH. Additionally, R. oryzae exposed to lovastatin showed macroscopic loss of melanin, yielded increased susceptibility to the oxidative agent peroxide, and had attenuated virulence in both fly and mouse models of mucormycosis.

CONCLUSIONS

Exposure of R. oryzae to statins at concentrations below their MICs decreased virulence both in vitro and in vivo. Further investigation is warranted into the use of statins as adjunctive therapy in mucormycosis.

Coenzyme Q10 remarkably improves the bio-energetic function of rat liver mitochondria treated with statins

CoQ10 shares a biosynthetic pathway with cholesterol therefore it can be a potential target of the widely available lipid-lowering agents such as statins. Statins are the most widely prescribed cholesterol-lowering drugs with the ability to inhibit HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase. Preclinical and clinical safety data have shown that statins do not cause serious adverse effects in humans. However, their long-term administration is associated with a variety of myopatic complaints. The aim of this study was to investigate whether CoQ10 supplementation of animals under high fat diet (HFD) treated with statins is able to bypass the mitochondrial metabolic defects or not? Animals were divided into 7 groups and fed with either regular (RD) or HFD during experiments. The first group considered as regular control and fed with a RD. Groups 2-7 including HFD control, CoQ10 (10mg/kg), simvastatin (30mg/kg), atorvastatin (30mg/kg), simvastatin+CoQ10 or atorvastatin+CoQ10 treated orally for 30 days and fed with HFD. At the end of treatments, the animals were killed and blood samples were collected for biochemical examinations. The rat liver mitochondria were isolated and several mitochondrial indices including succinate dehydrogenase activity (SDA), ATP levels, mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (MPP) were determined. We found that triglyceride (Tg), cholesterol (Chol) and low-density lipoprotein (LDL) were augmented with HFD compared to RD and treatment with statins remarkably lowered the Tg, Chol and LDL levels. Mitochondrial parameters including, SDA, ATP levels, MMP and MPP were reduced with statin treatment and improved by co-administration with CoQ10.

Hypercholesterolemia induces angiogenesis and accelerates growth of breast tumors in vivo

Obesity and metabolic syndrome are linked to an increased prevalence of breast cancer among postmenopausal women. A common feature of obesity, metabolic syndrome, and a Western diet rich in saturated fat is a high level of circulating cholesterol. Epidemiological reports investigating the relationship between high circulating cholesterol levels, cholesterol-lowering drugs, and breast cancer are conflicting. Here, we modeled this complex condition in a well-controlled, preclinical animal model using innovative isocaloric diets. Female severe combined immunodeficient mice were fed a low-fat/no-cholesterol diet and then randomized to four isocaloric diet groups: low-fat/no-cholesterol diet, with or without ezetimibe (cholesterol-lowering drug), and high-fat/high-cholesterol diet, with or without ezetimibe. Mice were implanted orthotopically with MDA-MB-231 cells. Breast tumors from animals fed the high-fat/high-cholesterol diet exhibited the fastest progression. Significant differences in serum cholesterol level between groups were achieved and maintained throughout the study; however, no differences were observed in intratumoral cholesterol levels. To determine the mechanism of cholesterol-induced tumor progression, we analyzed tumor proliferation, apoptosis, and angiogenesis and found a significantly greater percentage of proliferating cells from mice fed the high-fat/high-cholesterol diet. Tumors from hypercholesterolemic animals displayed significantly less apoptosis compared with the other groups. Tumors from high-fat/high-cholesterol mice had significantly higher microvessel density compared with tumors from the other groups. These results demonstrate that hypercholesterolemia induces angiogenesis and accelerates breast tumor growth in vivo.

Prevention of pulmonary hypoplasia and pulmonary vascular remodeling by antenatal simvastatin treatment in nitrofen-induced congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) has a high mortality rate mainly due to lung hypoplasia and persistent pulmonary hypertension of the newborn (PPHN). Simvastatin has been shown to prevent the development of pulmonary hypertension (PH) in experimental models of PH. We, therefore, hypothesized that antenatal simvastatin would attenuate PPHN in nitrofen-induced CDH in rats. The efficacy of antenatal simvastatin was compared with antenatal sildenafil, which has already been shown to improve pathological features of PPHN in nitrofen-induced CDH. On embryonic day (E) 9.5, nitrofen or vehicle was administered to pregnant Sprague-Dawley rats. On E11, nitrofen-treated rats were randomly assigned to antenatal simvastatin (20 mg·kg(-1)·day(-1) orally), antenatal sildenafil (100 mg·kg(-1)·day(-1) orally), or placebo administration from E11 to E21. On E21, fetuses were delivered by cesarean section, killed, and checked for left-sided CDH. Lung tissue was then harvested for further pathobiological evaluation. In nitrofen-induced CDH, simvastatin failed to reduce the incidence of nitrofen-induced CDH in the offspring and to increase the body weight, but improved the lung-to-body weight ratio and lung parenchyma structure. Antenatal simvastatin restored the pulmonary vessel density and external diameter, and reduced the pulmonary arteriolar remodeling compared with nitrofen-induced CDH. This was associated with decreased lung expression of endothelin precursor, endothelin type A and B receptors, endothelial and inducible nitric oxide synthase, together with restored lung activation of apoptotic processes mainly in the epithelium. Antenatal simvastatin presented similar effects as antenatal therapy with sildenafil on nitrofen-induced CDH. Antenatal simvastatin improves pathological features of lung hypoplasia and PPHN in experimental nitrofen-induced CDH.

Pharmacokinetic interactions between simvastatin and setipiprant, a CRTH2 antagonist

PURPOSE

Setipiprant, a selective oral CRTH2 antagonist, has been investigated for the treatment of allergic rhinitis and asthma. In vitro data showed that setipiprant has a weak induction potential on CYP3A4. An interaction at the hepatic level between setipiprant and CYP3A4 substrates was not expected even at the dosing regimen of 1,000 mg setipiprant b.i.d. due to the high plasma protein binding. However, at this dosing regimen, interactions at the gut level could not be excluded.

METHODS

In this single-center, open-label study, 40 mg of simvastatin was administered orally on Day 1, and then concomitantly with setipiprant on Day 10 following 9 days of setipiprant 1,000 mg b.i.d. to 22 healthy male subjects.

RESULTS

In the presence of setipiprant, the simvastatin concentration-time profile was similar to that of simvastatin alone. The concentrations of simvastatin were, however, slightly lower, resulting in a 9 % decrease in C max (geometric mean ratio (GMR) 0.91, 90 % confidence interval (CI) (0.73, 1.13)) and in a 16 % lower AUC0-∞ (GMR 0.84, 90 % CI (0.72, 0.99)). Exposure to simvastatin acid was similar when comparing simvastatin with or without setipiprant. The GMR and 90 % CI for AUC0-∞ were within the 0.8 to 1.25 limits, whereas those for C max were outside (GMR 2.73, 90 % CI (2.11, 3.53)). Moreover, the median t max of simvastatin acid occurred earlier (1.8 h) when combined compared to 3.0 h when administered alone.

CONCLUSIONS

As setipiprant has little impact on simvastatin pharmacokinetics, it does not modulate CYP3A4 in a clinically relevant manner.

Hypocholesterolaemic pharmaceutical simvastatin disrupts reproduction and population growth of the amphipod Gammarus locusta at the ng/L range

Simvastatin (SIM), a hypocholesterolaemic drug, is among the most widely used pharmaceuticals worldwide and is therefore of emerging environmental concern. Despite the ubiquitous nature of SIM in the aquatic ecosystems, significant uncertainties exist about sublethal effects of the drug in aquatic organisms. Therefore, here we aimed at investigating a multi-level biological response in the model amphipod Gammarus locusta, following chronic exposures to low levels of SIM (64 ng/L to 8 μg/L). The work integrated a battery of key endpoints at individual-level (survival, growth and reproduction) with histopathological biomarkers in hepatopancreas and gonads. Additionally, an individual-based population modelling was used to project the ecological costs associated with long-term exposure to SIM at the population level. SIM severely impacted growth, reproduction and gonad maturation of G. locusta, concomitantly to changes at the histological level. Among all analysed endpoints, reproduction was particularly sensitive to SIM with significant impact at 320 ng/L. These findings have important implications for environmental risk assessment and disclose new concerns about the effects of SIM in aquatic ecosystems.

Hypertensive disorders of pregnancy: preventative-, immediate- and long-term management

The hypertensive disorders of pregnancy are common and continue to be significant contributors to maternal and perinatal mortality and morbidity, both globally and in the UK. This review aims to describe the recent developments in the understanding of the pathophysiology of the disease processes, potential strategies for identification of women at high risk, and current and future therapeutic strategies for the treatment and prevention of hypertension in pregnancy. Women who experience adverse pregnancy outcomes are also at increased risk of premature cardiovascular disease, and potential therapeutic strategies to minimize their risk profile are discussed.

Lysophosphatidic acid pretreatment prevents micromolar atorvastatin-induced endothelial cell death and ensures the beneficial effects of high-concentration statin therapy on endothelial gene expression

Because of the pleiotropic effects of statins, it may potentially be used as a locoregional adjuvant in vascular revascularization, tissue engineering, and regenerative procedures. Electron probe X-ray microanalyses and oligonucleotide microarrays were used to identify the global effects of micromolar concentrations of atorvastatin on the gene expression and cell viability of endothelial cells in different states of lysophosphatidic acid (LPA)-induced activation. Treatment with 1-μM atorvastatin for 24 hours significantly reduced the viability of human vascular endothelial cells (HUVECs). However, the same treatment of LPA-preactivated HUVECs produced elevated cell viability levels and an optimal vascular gene expression profile, including endothelial nitric oxide synthase overexpression, endothelin-1 repression, an anti-inflammatory genetic pattern, and upregulation of molecules involved in maintaining the endothelial barrier (vascular endothelial cadherin, claudin 5, tight junction protein 1, integrin β4). The atorvastatin treatment also produced a repression of microRNA 21 and genes involved in cell proliferation and neointimal formation (vascular endothelial growth factor [VEGF] A, VEGF receptor 1, VEGFC). Results obtained suggest that micromolar atorvastatin therapy can enhance global endothelial function, but its effects on cell viability vary according to the baseline state of cell activation (preactivated, postactivated, or not activated). Preactivation with LPA protects HUVECs against atorvastatin-induced apoptosis and delivers optimal levels of cell viability and functionality.

Hypercholesterolemia promotes an osteoporotic phenotype

A role for hypercholesterolemia in the development of osteoporosis has been suggested in published reports. However, few studies contain direct evidence of a role for maintenance of cholesterol homeostasis in bone health. Using isocaloric high-fat/high-cholesterol and low-fat/no-cholesterol diets in a 4-month feeding study combined with micro computed tomography analysis, we demonstrated in two different mouse strains that mice with hypercholesterolemia lose cortical and trabecular bone in the femurs and vertebrae (bone mineral density was decreased on average by ≈90 mg/mL in the cortical vertebrae in one strain) and cortical bone in the calvariae (bone mineral density was decreased on average by ≈60 mg/mL in one strain). Mechanical testing of the femurs demonstrated that loss of bone in the mice with hypercholesterolemia caused changes in the mechanical properties of the bone including loss of failure load (failure load was decreased by ≈10 N in one strain) and energy to failure. Serologic and histomorphologic analyses suggested that hypercholesterolemia promotes osteoclastogenesis. These studies support a role for hypercholesterolemia in the development of osteoporosis and provide a model with which to test intervention strategies to reduce the effects of hypercholesterolemia on bone health.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Genotype-dependent effects of inhibitors of the organic cation transporter, OCT1: predictions of metformin interactions

Common genetic variants of the liver-specific human organic cation transporter 1 (OCT1; SLC22A1) have reduced transport capacity for substrates such as the antidiabetic drug metformin. The effect of the reduced OCT1 function on drug interactions associated with OCT1 has not been investigated and was, therefore, the focus of the study presented here. HEK293 cells expressing human OCT1-reference or the variants R61C, V408M, M420del and G465R were first used to study the kinetics and inhibition pattern of the OCT1 substrate 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)). In the second part OCT1-mediated (14)C-metformin uptake was studied in the presence of drugs administered concomitantly with metformin. Transport studies using ASP(+) showed that the function of the variants decreased in the following order: OCT1-reference=V408M=M420del >R61C >>G465R. Variants M420del and R61C were more sensitive to drug inhibition, with IC(50) values up to 23 times lower than those of the OCT1-reference. Uptake studies using (14)C-metformin were in qualitative agreement with those using ASP(+), with the exception that a larger reduction in transport capacity was observed for M420del. Concomitantly administered drugs, such as verapamil and amitriptyline, revealed potential drug-drug interactions at clinical plasma concentrations of metformin for OCT1-M420del.

Ezetimibe is an inhibitor of tumor angiogenesis

Epidemiological and preclinical observations have suggested a role for one or more products of the mevalonate/cholesterol biosynthesis pathway in the progression of prostate cancer. In this study, we used ezetimibe (Zetia), a specific, FDA-approved, cholesterol uptake-blocking drug, in combination with either a hyper- or hypocholesterolemic diet, to show that elevated circulating cholesterol levels promote, whereas a reduction in circulating cholesterol levels retard, the growth of human prostate cancer xenograft tumors in mice. Circulating cholesterol levels also modified tumor angiogenesis; higher cholesterol levels increased microvessel density and other indicators of vascularity. Consistent with these data, the reduction of cholesterol levels also increased the levels of the angiogenesis inhibitor thrombospondin-1 in the xenografts. Our results thus suggest that hypercholesterolemia directly accelerates the growth of prostate carcinomas, and that the pharmacological reduction of serum cholesterol levels may retard prostate cancer growth by inhibiting tumor angiogenesis.

Simvastatin therapy in cyclosporine A-induced alveolar bone loss in rats

BACKGROUND AND OBJECTIVE

Cyclosporine A treatment is important in the therapy of a number of medical conditions; however, alveolar bone loss is an important negative side-effect of this drug. As such, we evaluated whether concomitant administration of simvastatin would minimize cyclosporine A-associated alveolar bone loss in rats subjected, or not, to experimental periodontal disease.

MATERIAL AND METHODS

Groups of 10 rats each were treated with cyclosporine A (10 mg/kg/day), simvastatin (20 mg/kg/day), cyclosporine A and simvastatin concurrently (cyclosporine A/simvastatin) or vehicle for 30 days. Four other groups of 10 rats each received a cotton ligature around the lower first molar and were treated similarly with cyclosporine A, simvastatin, cyclosporine A/simvastatin or vehicle. Calcium (Ca(2+)), phosphorus and alkaline phosphatase levels were evaluated in serum. Expression levels of interleukin-1beta, prostaglandin E(2) and inducible nitric oxide synthase were evaluated in the gingivomucosal tissues. Bone volume and numbers of osteoblasts and osteoclasts were also analyzed.

RESULTS

Treatment with cyclosporine A in rats, with or without ligature, was associated with bone loss, represented by a lower bone volume and an increase in the number of osteoclasts. Treatment with cyclosporine A was associated with bone resorption, whereas simvastatin treatment improved cyclosporine A-associated alveolar bone loss in all parameters studied. In addition, simvastatin, in the presence of inflammation, can act as an anti-inflammatory agent.

CONCLUSION

This study shows that simvastatin therapy leads to a reversal of the cyclosporine A-induced bone loss, which may be mediated by downregulation of interleukin-1beta and prostaglandin E(2) production.

Hormesis and medicine

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.

The prince and the pauper. A tale of anticancer targeted agents

Cancer rates are set to increase at an alarming rate, from 10 million new cases globally in 2000 to 15 million in 2020. Regarding the pharmacological treatment of cancer, we currently are in the interphase of two treatment eras. The so-called pregenomic therapy which names the traditional cancer drugs, mainly cytotoxic drug types, and post-genomic era-type drugs referring to rationally-based designed. Although there are successful examples of this newer drug discovery approach, most target-specific agents only provide small gains in symptom control and/or survival, whereas others have consistently failed in the clinical testing. There is however, a characteristic shared by these agents: -their high cost-. This is expected as drug discovery and development is generally carried out within the commercial rather than the academic realm. Given the extraordinarily high therapeutic drug discovery-associated costs and risks, it is highly unlikely that any single public-sector research group will see a novel chemical "probe" become a "drug". An alternative drug development strategy is the exploitation of established drugs that have already been approved for treatment of non-cancerous diseases and whose cancer target has already been discovered. This strategy is also denominated drug repositioning, drug repurposing, or indication switch. Although traditionally development of these drugs was unlikely to be pursued by Big Pharma due to their limited commercial value, biopharmaceutical companies attempting to increase productivity at present are pursuing drug repositioning. More and more companies are scanning the existing pharmacopoeia for repositioning candidates, and the number of repositioning success stories is increasing. Here we provide noteworthy examples of known drugs whose potential anticancer activities have been highlighted, to encourage further research on these known drugs as a means to foster their translation into clinical trials utilizing the more limited public-sector resources. If these drug types eventually result in being effective, it follows that they could be much more affordable for patients with cancer; therefore, their contribution in terms of reducing cancer mortality at the global level would be greater.

Simvastatin induces cell death in a mouse cerebellar slice culture (CSC) model of developmental myelination

Statins (inhibitors of HMG-CoA reductase) have shown promise in treating multiple sclerosis (MS). However, their effect on oligodendrocyte remyelination of demyelinated axons has not been clarified. Since developmental myelination shares many features with the remyelination process, we investigated the effect of lipophilic simvastatin on developmental myelination in organotypic cerebellar slice cultures (CSC). In this study, we first characterized developmental myelination in CSC from postnatal day (P)5 and P10 mice that express enhanced green fluorescence protein (eGFP) in oligodendrocyte-lineage cells. We then examined the effect of simvastatin on three developmental myelination stages: early myelination (P5 CSC, 2DIV), late myelination (P10 CSC, 2DIV) and full myelination (P10 CSC, 10DIV). We found that treatment with simvastatin (0.1 microM) for 6 days decreased the survival of Purkinje cells and oligodendrocytes drastically during the early myelination stage, while moderately during the late and full myelination stages. Oligodendrocytes are more resistant than Purkinje cells. The toxic effect of simvastatin could be rescued by the product of HMG-CoA reductase mevalonate but not low-density lipoprotein (LDL). Additionally, this toxic effect is independent of isoprenylation since farnesyl pyrophosphate (Fpp) but not geranylgeranyl pyrophosphate (GGpp) provided partial rescue. Our findings therefore suggest that inhibition of cholesterol synthesis is detrimental to neuronal tissue.

Do the cholesterol-lowering properties of statins affect cancer risk?

The potential of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors ('statins') to reduce the incidence and/or progression of certain malignancies remains uncertain. Some investigators have concluded that statins have no effects on malignancies of any kind. However, results of several epidemiologic studies, including four recent prospective cohort studies, suggest that long-term statin therapy inhibits the progression of prostate cancer. We argue that the principal mechanism of any anticancer effects from statin use arises from prolonged lowering of circulating cholesterol. Evidence suggests that prostate cancer might be particularly sensitive to this intervention. Our hypothesis provides a perspective from which mechanistic studies of cholesterol-lowering drugs and cancer, in addition to prospective trials in patients, might be designed.

Chromatography–mass spectrometry methods for the quantitation of statins in biological samples

The 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors, more commonly known as 'statins', are a novel class of drugs widely used for the treatment of hypercholesterolaemia in patients with established cardiovascular disease as well as those at high risk of developing atherosclerosis. Published chromatographic-mass spectrometric methods for the quantification of presently available seven statins, atorvastatin, simvastatin, lovastatin, pravastatin, fluvastatin, rosuvastatin and pitavastatin are reviewed. High performance liquid chromatography (HPLC) in combination with tandem mass spectrometry (MS/MS) is the analytical technique of choice for the quantification of statins in biological samples. This review envisages that most of the methods used for quantification of statins are in plasma and they are suitable for therapeutic drug monitoring of these drugs.

Effects of atorvastatin and simvastatin on atrial plateau currents

Recent evidence has shown that the inhibitors of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) might exert antiarrhythmic effects both in experimental models and in humans. In this study we analyzed the effects of atorvastatin and simvastatin acid (SVA) on the currents responsible for the duration of the plateau of human atrial action potentials: hKv1.5, Kv4.3, and L-type Ca(2+) (I(Ca,L)). hKv1.5 and Kv4.3 currents were recorded in transfected Ltk(-) and Chinese hamster ovary cells, respectively, and I(Ca,L) in mouse ventricular myocytes, using whole-cell patch-clamp. Atorvastatin and SVA produced a concentration-dependent block of hKv1.5 channels (IC(50)=4.5+/-1.7 microM and 5.7+/-0.03 microM, respectively) and shifted the midpoint of the activation and inactivation curves to more negative potentials. Importantly, atorvastatin- and SVA-induced block was added to that produced by quinidine, a drug that blocks hKv1.5 channels by binding to their pore cavity. Atorvastatin and SVA blocked Kv4.3 channels in a concentration-dependent manner (IC(50)=13.9+/-3.6 nM and 7.0+/-0.8 microM, respectively). Both drugs accelerated the inactivation kinetics and shifted the inactivation curve to more negative potentials. SVA (10 nM), but not atorvastatin, also blocked I(Ca,L) producing a frequency-dependent block that, at 2 Hz, reached a 50.2+/-1.5%. As a consequence of these effects, at nanomolar concentrations, atorvastatin lengthened, whereas SVA shortened, the duration of mouse atrial action potentials. The results suggest that atorvastatin and SVA alter Kv1.5 and Kv4.3 channel activity following a complex mechanism that does not imply the binding of the drug to the channel pore.

Stacking and quantitative analysis of lovastatin in urine samples by the transient moving chemical reaction boundary method in capillary electrophoresis

A simple, sensitive, and useful concentration method for lovastatin (Lvt) in urine has been developed based on the transient moving chemical reaction boundary method (tMCRBM) in capillary electrophoresis. The MCRB is formed with acidic sample buffer (Gly-HCl) and alkaline running buffer (Gly-NaOH). The following optimal conditions were determined for stacking and separation: electrophoretic buffer of 100 mM Gly- NaOH (pH 11.52), sample buffer of 20 mM Gly-HCl (pH 4.93), fused-silica capillary of 76 cm x 75-microm i.d (67 cm from detector), sample injection at 14 mbar for 3 min. A 21- to 26-fold increase in peak height was achieved for detection of Lvt in urine under the optimal conditions compared with normal capillary zone electrophoresis. By combining the sample pretreatment procedure with the stacking method, the sensitivity of Lvt in urine was increased by 105- to 130-fold. The limits of detection (LOD) and quantification (LOQ) for Lvt in urine were decreased to 8.8 ng/mL and 29.2 ng/mL, respectively. The intra-day and inter-day precision values (expressed as RSD) were 2.23-3.61% and 4.03-5.05%, respectively. The recoveries of the analyte at three concentration levels changed from 82.65 to 100.49%.

Tolerability of statins is not linked to CYP450 polymorphisms, but reduced CYP2D6 metabolism improves cholesteraemic response to simvastatin and fluvastatin

Statin therapy, although generally well tolerated, leads not infrequently to significant subjective and at times objective adverse effects (AEs), mainly of a muscular nature. The genetic background of these AEs is not clear and possibly side effects and lipid lowering efficacy may be linked. Aim of the study was a detailed evaluation of CYP450 and apolipoprotein E gene polymorphisms in two large series of age-sex matched patients with and without muscular side effects to statins. In a Clinical Institution specialised in lipid-lipoprotein disorders, 50 statin treated patients were selected, with subjective or objective statin-associated myopathy, evaluated using standardized forms. These were sex and age matched with 50 statin-treated patients from the same Clinic, without any subjective or objective complaints. DNA samples for the evaluation of CYP450 genetic polymorphisms and apo E genotypes were collected in order to assess correlations with both genetic polymorphisms and AEs, as well as with therapeutic efficacy. None of the assessed CYP450 polymorphisms appeared to be related to an increased incidence of AEs. The CYP2D6 *1/*4 and *4/4* poor metabolizer (PM) status was associated to a higher efficacy of statins metabolized by this system and, in addition, the apo E2 genotype was, in this series, linked to increased HDL-C levels after therapy. Patients with statin associated myopathy are not characterized by significantly different genotypes for the CYP450s responsible for statin metabolism. On the other hand, CYP2D6 PM status is associated to an increased efficacy of statins metabolized by this system.