New insights into the pharmacodynamic and pharmacokinetic properties of statins

Geranylgeraniol prevents the simvastatin-induced PCSK9 expression: Role of the small G protein Rac1

Statins are known to increase the plasma levels of proprotein convertase subtilisin kexin type 9 (PCSK9) through the activation of the sterol responsive element binding protein (SREBP) pathway due to the inhibition of cholesterol biosynthesis. In the present study, we explore a possible role of the prenylated proteins on the statin-mediated PCSK9 induction in Caco-2 cells. Simvastatin (40μM) induced both PCSK9 mRNA (10.7±3.2 fold) and protein (2.2±0.3 fold), after 24h incubation. The induction of PCSK9 mRNA was partially, but significantly, prevented by the co-incubation with mevalonate (MVA), farnesol (FOH) and geranylgeraniol (GGOH), while a complete prevention was observed on secreted PCSK9, evaluated by ELISA assay. Under the same experimental conditions, MVA, GGOH, but not FOH, prevented the activation of the PCSK9 promoter by simvastatin in a SRE-dependent manner. Simvastatin reduced by -35.7±15.2% the Rac1-GTP levels, while no changes were observed on RhoA- and Cdc42-GTP. This effect was prevented by MVA and GGOH. A Rac inhibitor, and N17Rac1 dominant negative mutant, significantly induced PCSK9 levels, and a suppression of Rac1 expression by siRNA, counteract the effect of simvastatin on the induction of PCSK9 mRNA. Finally, simvastatin, and Rac inhibitor inhibited the nuclear translocation of STAT3 and its knock-down by siRNA increased significantly the susceptibility of Caco-2 to simvastatin on PCSK9 expression. Taken together, the present study reveal a direct role of Rac1 on simvastatin-mediated PCSK9 expression via the reduction of STAT3 nuclear translocation.

Do statins really cause diabetes? A meta-analysis of major randomized controlled clinical trials

Objectives:

To investigate and establish the relationship between the use of statin therapy and the risk of development of diabetes.

Methods:

PubMed and the Cochrane Central Register of Controlled Trials was searched for randomized controlled end-point trials of statins, with more than 1000 subjects and a minimum of one-year follow-up period, published until August 2015. The odds ratio (OR) of diabetes incidence with overall statin therapy as well as with different statins in question was calculated through random effect meta-analysis model.

Results:

Fourteen studies were included in the analysis with a total of 94,943 participants. Of these, 2392 subjects developed incident diabetes in the statin and 2167 in the placebo groups during a 4-year follow-up. The OR of diabetes incidence with statin therapy was significantly higher as compared with the placebo group (OR=1.11; 95% confidence interval = 1.0 to 1.2; p=0.007). There was an insignificant level of heterogeneity between the included trials (Cochran Q= 19.463, p=0.109, I²=33.20). Subgroup analysis showed that only 2 statins namely, atorvastatin (OR= 1.29; p=0.042) and rosuvastatin (OR = 1.17; px=0.01) were significantly associated.

Conclusion:

Statin therapy can slightly increase risk of incident diabetes in subjects with hypercholesterolemia.

Association of Cognitive Impairment in Patients on 3-Hydroxy-3-Methyl-Glutaryl-CoA Reductase Inhibitors

BACKGROUND

Atherosclerotic cardiovascular diseases are the leading cause of death in the United States. A reduction in cholesterol with 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statin) significantly reduces mortality and morbidity. Statins may be associated with cognitive impairment or dementia. Our aim was to study the association of cognitive impairment or dementia in patients who were on a statin.

METHODS

Electronic medical records of 3,500 adult patients in our suburban internal medicine office were reviewed.

RESULTS

There were 720 (20.6%) patients in the statin treatment group. Dementia or cognitive impairment was an associated comorbid condition in 7.9% patients in the statin treatment group compared to 3.1% patients in the non-statin group (P < 0.001). Analysis of all of the patients with cognitive impairment or dementia showed that among the age ranges of 51 years through 100 years, the patients in the statin treatment group had a higher prevalence of cognitive impairment or dementia compared to the non-statin group. In the statin treatment group, we found significantly higher prevalence of hyperlipidemia (86.3%), hypertension (69.6%), diabetes mellitus (36.0%), osteoarthritis (31.5%), coronary artery disease (26.1%), hypothyroidism (21.5%) and depression (19.3%) compared to the non-statin group (P < 0.001). About 39.9% of the patients with dementia or cognitive impairment were on statin therapy compared to 18.9% patients who had no dementia or cognitive impairment and were on statin therapy (P < 0.001). Among the patients with cognitive deficit or dementia in the statin treatment group, the majority of the patients were either on atorvastatin (43.9%) or simvastatin (35.1%), followed by rosuvastatin (12.2%) and pravastatin (8.8%). We found greater odds of dementia or cognitive impairment with each year increase in age (1.3 times), in women (2.2 times), African American race (2.7 times), non-consumption of moderate amount of alcohol (two times), diabetes mellitus (1.6 times), hypothyroidism (1.7 times), cerebrovascular accident (3.2 times), and other rheumatological diseases (1.8 times).

CONCLUSIONS

The association of dementia or cognitive impairment was significantly higher in the patients who were on statin therapy compared to the patients who were not on a statin.

Compounding and stability evaluation of atorvastatin extemporaneous oral suspension using tablets or pure powder

Background

Statins are the first-line therapy for lowering high lipid levels. Atorvastatin calcium (AtC) is the most commonly prescribed statin. It inhibits 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase which converts HMG-CoA into mevalonic acid, a cholesterol precursor.

Objective

To compound and evaluate the stability of AtC suspension (0.4% w/v) using commercial tablets or pure AtC powder as the source of the active pharmaceutical ingredient.

Method

Several AtC suspension formulations were produced using commercial AtC tablets or AtC pure powder as the source of the active ingredient. The most suitable one in terms of general organoleptic properties and dissolution was selected for stability studies. For this purpose, samples of final suspensions were stored at room temperature and in the refrigerator. Assay, pH, organoleptic properties and microbial contamination were evaluated according to the USP specifications. High performance liquid chromatography was used for the analysis and quantification of AtC in the studied samples.

Results

The obtained suspension (S4) had good organoleptic properties. It showed complete dissolution of AtC within 30 min. However, the suspension prepared from crushed tablet (S_t4) showed a better dissolution profile than that prepared from pure powder (S_p4). The prepared formula had unchanged pH, which remained around 9.9. S_t and S_p formulas were both free from microbial contamination. Both products showed good stability within at least the period of use of the 100 mL AtC bottles.

Conclusions

AtC extemporaneous suspension was successfully prepared using tablets as a source of AtC or pure AtC powder. However, S_t4 had a better dissolution profile than S_p4. This study provides a solution for patients with swallowing difficulties or feeding tubes who are unable to take medicines in solid oral dosage forms. Community pharmacists can prepare the suspension using AtC tablets as the source of the active ingredient.

Orally administered simvastatin partially preserves lumbar vertebral bone mass but not integrity of intervertebral discs in ovariectomized rats

The present study aimed to investigate the effect of orally administered simvastatin on lumbar vertebral bone mass and intervertebral disc (IVD) degeneration in ovariectomized (OVX) rats. A total of 30 female Sprague-Dawley (SD) rats were subjected to either bilateral ovariectomy (n=20) or sham surgery (n=10). After 12 weeks, the OVX rats were orally administered either saline vehicle (OVX + V group; n=10), or 5 mg/kg/day simvastatin (OVX + SIM group; n=10). Following 12 weeks of treatment, necropsy was conducted and bone mineral density (BMD) was determined in the L5-6 vertebrae. Furthermore, the microstructure and biomechanical properties of the L3 vertebrae were detected by micro-computed tomography and compression testing, respectively. The L5-6 vertebrae were analyzed by measurement of IVD height, observation of histological changes by van Gieson staining, and evaluation of collagen-II (col-II), aggrecan (AGG) and collagen I (col-I) expression by immunohistochemical analysis. Rats in the OVX+V group had lower BMD, bone volume/trabecular volume ratio, maximum load and elastic modulus than the sham group. Rats in the OVX + SIM group had higher BMD and biomechanical strength values than the rats in the OVX+V group. Histological analysis showed that the OVX + V and OVX + SIM groups exhibited significantly higher disc degeneration scores and significantly lower IVD height than the sham group. Immunohistochemical analysis revealed lower expression levels of col-II and AGG, but higher levels of col-I in the annulus fibrosis and endplate in OVX+V rats compared with the sham group. The OVX + SIM group exhibited levels of col-II, AGG and col-I expression comparable with those of OVX+V rats, with the exception of an upregulation of col-II expression in the annulus fibrosis. These data demonstrate that simvastatin treatment partially prevented bone loss and the deterioration of biomechanical properties of lumbar vertebrae, but not the progression of IVD degeneration in OVX rats.

Effects of Different Types of Statins on Lipid Profile: A Perspective on Asians

CONTEXT

The present review aimed at reviewing the effects of different statins on lipid profile, particularly in Asians.

EVIDENCE ACQUISITION

PubMed searches were conducted using the keywords 'statin, effect, and lipid profile' from database inception through March 2016. In this review, 718 articles were retrieved from the primary search. After reviewing the titles, abstracts, and full texts, we found that 59 studies met our inclusion criteria. These also included subsequent reference searches of retrieved articles.

RESULTS

CURVES study compared the effect on lipid profile between atorvastatin and other statins. This study demonstrated that low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG) were reduced more with atorvastatin compared to simvastatin, pravastatin, lovastatin, and fluvastatin. However, simvastatin provided a greater elevation of high-density lipoprotein cholesterol (HDL-C) compared to atorvastatin. The STELLAR trial was based on dose-to-dose comparisons between atorvastatin and rosuvastatin efficacy in reducing LDL-C. Te present study also revealed that as the doses of rosuvastatin, simvastatin, and pravastatin increased, HDL-C also increased, with rosuvastatin having the greatest effect. However, HDL-C levels decreased as the dose of atorvastatin increased. The DISCOVERY study involving the Asian population revealed that the percentage of patients achieving the European goals for LDL-C and TC at 12 weeks was higher in rosuvastatin group compared to atorvastatin group.

CONCLUSIONS

The effects of statins on lipid profile are dose dependent. Most studies showed that rosuvastatin has the best effect on lipid profile. Prescribing lower doses of statins in Asians seems necessary.

Technological advances and proteomic applications in drug discovery and target deconvolution: identification of the pleiotropic effects of statins

Proteomic-based techniques provide a powerful tool for identifying the full spectrum of protein targets of a drug, elucidating its mechanism(s) of action, and identifying biomarkers of its efficacy and safety. Herein, we outline the technological advancements in the field, and illustrate the contribution of proteomics to the definition of the pharmacological profile of statins, which represent the cornerstone of the prevention and treatment of cardiovascular diseases (CVDs). Statins act by inhibiting 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, thus reducing cholesterol biosynthesis and consequently enhancing the clearance of low-density lipoproteins from the blood; however, HMG-CoA reductase inhibition can result in a multitude of additional effects beyond lipid lowering, known as 'pleiotropic effects'. The case of statins highlights the unique contribution of proteomics to the target profiling of a drug molecule.

Statin use and uterine fibroid risk in hyperlipidemia patients: a nested case-control study

BACKGROUND

Statins are 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors primarily used for treatment of hyperlipidemia. Recently, they have been shown to inhibit proliferation of uterine fibroid cells and inhibit tumor growth in fibroid animal models.

OBJECTIVE

We sought to examine the association between statin use and the risk of uterine fibroids and fibroid-related symptoms in a nationally representative sample of commercially insured women diagnosed with hyperlipidemia.

STUDY DESIGN

We performed a nested case-control study of >190,000 women enrolled in one of the nation's largest commercial health insurance programs. From a cohort of women aged 18-65 years diagnosed with hyperlipidemia from January 2004 through March 2011, we identified 47,713 cases (women diagnosed with uterine fibroids) and 143,139 controls (women without uterine fibroids) matched at a 1:3 ratio on event/index date (month and year) and age (±1 year). We used conditional and unconditional logistic regression to calculate odds ratios and 95% confidence intervals for the risk of uterine fibroids and fibroid-related symptoms associated with prior use of statins.

RESULTS

Exposure to statins within 2 years before the event/index date was associated with a decreased risk of uterine fibroids (odds ratio, 0.85; 95% confidence interval, 0.83-0.87). In a separate subanalysis restricted to cases, statin users had a lower likelihood of having menorrhagia (odds ratio, 0.88; 95% confidence interval, 0.84-0.91), anemia (odds ratio, 0.84; 95% confidence interval, 0.79-0.88), or pelvic pain (odds ratio, 0.85; 95% confidence interval, 0.81-0.91) and of undergoing myomectomy (odds ratio, 0.76; 95% confidence interval, 0.66-0.87) compared to nonusers.

CONCLUSION

The use of statins was associated with a lower risk of uterine fibroids and fibroid-related symptoms. Further studies, including randomized controlled trials, may be warranted.

POSSIBLE REGULATION OF LDL-RECEPTOR BY NARINGENIN IN HEPG2 HEPATOMA CELL LINE

Background:

High plasma concentration of low-density lipoprotein cholesterol (LDL-c) plays a significant role in the incidence of atherosclerosis and coronary heart diseases (CHD).

Materials and Methods:

The purpose of this study was to investigate the mechanism by which citrus flavonoids, naringenin regulate the LDL receptor (LDLr) gene in human liver using the human hepatoma cell line, HepG2 as a model.

Results:

Time-course transient transfection of HepG2 cells with luciferase reporter-gene constructs incorporating the promoters of SREBP-1a,-1c, -2 and LDLr, revealed that in lipoprotein-deficient medium (LPDM), only SREBP-1a promoter activity was increased significantly after 4h exposure to 200μM naringenin respectively. However, after 24h incubation with 200μM naringenin the gene expression activities of all the SREBP-1a, -1c, -2 and LDLr promoter-constructs were increased significantly. The effects of both 200μM naringenin on elevating LDLr mRNA are possibly due to regulation of gene transcription by SREBP-la and SREBP-2. However, the suppression effect of 200μM naringenin on hepatic SREBP-1c mRNA expression is likely associated with the reduction in mRNA expression of both acetyl-CoA carboxylase and fatty acid synthase in human hepatoma HepG2 cells. It was found that, 200μM naringenin was likely to stimulate LDLr gene expression via increase phosphorylation of PI3K and ERK1/2 which enhance the transcription factors SREBP-1a and SREBP-2 mRNA levels and increased their protein maturation in human hepatoma HepG2 cell.

Conclusion:

Diets supplemented with naringenin could effectively reduce mortality and morbidity from coronary heart diseases and as cardio-protective effects in humans.

Repurposing Treatments to Enhance Innate Immunity. Can Statins Improve Neutrophil Functions and Clinical Outcomes in COPD?

Drug classes used in the treatment of Chronic Obstructive Pulmonary Disease (COPD) have not changed for many years, and none to date have shown disease-modifying activity. Statins are used to help reduce cardiovascular risk, which is high in many patients with COPD. Their use has been associated with improvements in some respiratory manifestations of disease and reduction in all-cause mortality, with greatest reductions seen in patients with the highest inflammatory burden. The mechanism for these effects is poorly understood. Neutrophils are key effector cells in COPD, and correlate with disease severity and inflammation. Recent in vitro studies have shown neutrophil functions are dysregulated in COPD and this is thought to contribute both to the destruction of lung parenchyma and to the poor responses seen in infective exacerbations. In this article, we will discuss the potential utility of statins in COPD, with a particular emphasis on their immune-modulatory effects as well as presenting new data regarding the effects of statins on neutrophil function in vitro.

Pediatric Statin Administration: Navigating a Frontier with Limited Data

Increasingly, children and adolescents with dyslipidemia qualify for pharmacologic intervention. As they are for adults, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are the mainstay of pediatric dyslipidemia treatment when lifestyle modifications have failed. Despite the overall success of these drugs, the magnitude of variability in dose-exposure-response profiles contributes to adverse events and treatment failure. In children, the cause of treatment failures remains unclear. This review describes the updated guidelines for screening and management of pediatric dyslipidemia and statin disposition pathway to assist the provider in recognizing scenarios where alterations in dosage may be warranted to meet patients' specific needs.

Protein Prenylation Constitutes an Endogenous Brake on Axonal Growth

Suboptimal axonal regeneration contributes to the consequences of nervous system trauma and neurodegenerative disease, but the intrinsic mechanisms that regulate axon growth remain unclear. We screened 50,400 small molecules for their ability to promote axon outgrowth on inhibitory substrata. The most potent hits were the statins, which stimulated growth of all mouse- and human-patient-derived neurons tested, both in vitro and in vivo, as did combined inhibition of the protein prenylation enzymes farnesyltransferase (PFT) and geranylgeranyl transferase I (PGGT-1). Compensatory sprouting of motor axons may delay clinical onset of amyotrophic lateral sclerosis (ALS). Accordingly, elevated levels of PGGT1B, which would be predicted to reduce sprouting, were found in motor neurons of early- versus late-onset ALS patients postmortem. The mevalonate-prenylation pathway therefore constitutes an endogenous brake on axonal growth, and its inhibition provides a potential therapeutic approach to accelerate neuronal regeneration in humans.

Rhabdomyolysis with Concurrent Atorvastatin and Diltiazem

OBJECTIVE:

To report a case of rhabdomyolysis and acute hepatitis associated with the coadministration of atorvastatin and diltiazem.

CASE SUMMARY:

A 60-year-old African American man with a significant past medical history presented to the emergency department with acute renal failure secondary to rhabdomyolysis. In addition, liver enzymes were elevated to greater than 3 × normal. The only change in medication was the initiation of diltiazem 3 weeks earlier for atrial fibrillation to a complicated medication regimen that included atorvastatin.

DISCUSSION:

Rhabdomyolysis has been reported in patients receiving hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors when coadministered with agents that may inhibit their metabolism. Atorvastatin is the most potent of this class of agents currently available and is commonly used in the treatment of hyperlipidemia. Rhabdomyolysis resulting from the drug interaction between diltiazem and other HMG-CoA reductase inhibitors has been described in the literature. However, no report has specifically associated this adverse event with atorvastatin and diltiazem. We describe a patient with a complex medication regimen who was admitted for rhabdomyolysis and accompanying acute renal failure, along with acute hepatitis, thought to be secondary to a drug interaction between atorvastatin and diltiazem.

CONCLUSIONS:

While optimizing the patient's lipid profile should be the primary factor in choosing one statin over another, the potential for drug interactions requires close attention. All patients beginning HMG-CoA reductase inhibitor therapy should be counseled regarding the signs and symptoms of muscle injury; particular attention should be paid to those patients who are taking medications that may interact.

Lovastatin Analogues from the Soil-Derived Fungus Aspergillus sclerotiorum PSU-RSPG178

Three new lovastatin analogues (1, 4, and 5) together with four known lovastatin derivatives, namely, lovastatin (2), α,β-dehydrolovastatin (3), α,β-dehydrodihydromonacolin K (6), and α,β-dehydro-4a,5-dihydromonacolin L (7), were isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178. Their structures were established using spectroscopic evidence. Compound 5 exhibited the most potent activity against HMG-CoA reductase, with an IC50 value of 387 μM. In addition, the present study indicated the direct interaction of compound 5 with HMG-CoA reductase. Compound 5 was considered to be noncytotoxic against noncancerous Vero cells, with an IC50 value of 40.0 μM, whereas compound 2 displayed much stronger activity, with an IC50 value of 2.2 μM.

Pleiotropic effects of statins: new therapeutic targets in drug design

The HMG Co-enzyme inhibitors and new lipid-modifying agents expand their new therapeutic target options in the field of medical profession. Statins have been described as the most effective class of drugs to reduce serum cholesterol levels. Since the discovery of the first statin nearly 30 years ago, these drugs have become the main therapeutic approach to lower cholesterol levels. The present scientific research demonstrates numerous non-lipid modifiable effects of statins termed as pleiotropic effects of statins, which could be beneficial for the treatment of various devastating disorders. The most important positive effects of statins are anti-inflammatory, anti-proliferative, antioxidant, immunomodulatory, neuroprotective, anti-diabetes, and antithrombotic, improving endothelial dysfunction and attenuating vascular remodeling besides many others which are discussed under the scope of this review. In particular, inhibition of Rho and its downstream target, Rho-associated coiled-coil-containing protein kinase (ROCK), and their agonistic action on peroxisome proliferator-activated receptors (PPARs) can be viewed as the principle mechanisms underlying the pleiotropic effects of statins. With gradually increasing knowledge of new therapeutic targets of statins, their use has also been advocated in chronic inflammatory disorders for example rheumatoid arthritis (RA) and in systemic lupus erythematosus (SLE). In the scope of review, we highlight statins and their pleiotropic effects with reference to their harmful and beneficial effects as a novel approach for their use in the treatment of devastating disorders. Graphical abstract Pleiotropic effect of statins.

Potential of novel drug delivery strategies for the treatment of hyperlipidemia

Emergence of hyperlipidemia in urban population of India and the world at large is very high and accounts to several fatal diseases. This condition is known to manifest elevated levels of lipids and/or lipoproteins. Serious limitations like inadequate solubility, less absorption, less bioavailability, ineffectiveness in lowering of cholesterol levels, patient incompliance and so on are noticed with majority of anti-hyperlipidemic drugs and dosage forms, which are used conventionally. To overcome these shortcomings, building technology platforms for development of appropriate dosage forms is the need of the hour. These efforts are required to maximize patient acceptability while maintaining safety, efficacy, accessibility and affordability. Hyperlipidemia, its types, etiology, pathophysiology and conventional dosage forms are discussed here. The current approaches and novel developments which illustrate controlled drug release and sustained therapeutic effect along with site specific and target oriented drug delivery with better patient compliance are also reviewed critically. Despite the incentives provided by the efforts of formulation scientists, there is still a need for implementation of pharmaceutical technologies that enable to combat limitations of anti-hyperlipidemic drugs and conventional dosage forms associated with it. The present review emphasize on applications of novel drug delivery systems in pharmacotherapy of anti-hyperlipidemic drugs demonstrating the advantages and disadvantages.

Management of intracerebral hemorrhage--use of statins

Intracerebral hemorrhage (ICH) is a neurologic injury resulting in significant morbidity and mortality. Statins play a significant role in primary and secondary prevention of cardiovascular and cerebrovascular ischemic events. Despite clear benefits of statins in ischemic stroke, post hoc analyses of some studies suggest there may be a link between statin therapy and development of ICH. Direct pharmacologic effects of decreased serum levels of total cholesterol and low-density lipoproteins in conjunction with pleiotropic effects are thought to be linked to this possible increase in ICH risk. In the face of the potential of statins to increase the risk of ICH, recent evidence suggests that statins may also have beneficial effects on patient outcomes when continued or initiated following an ICH. This discordance in findings and the overall lack of well-designed prospective clinical trials increase the complexity of clinical decision making when utilizing statin therapy in patients with, or at risk for, ICH. This review evaluates the pharmacologic effects of statin therapy and describes how these effects translate to both risks and benefits in ICH. The current literature regarding the effects of statin therapy on clinical outcomes in ICH is evaluated to help guide clinicians with decisions regarding initiation, continuation, or discontinuation of statin therapy in patients with ICH.

Statins for Primary Prevention of Cardiovascular Disease in Elderly Patients: Systematic Review and Meta-Analysis

BACKGROUND

Statins have been shown to be beneficial in primary and secondary prevention settings; however, their role in the elderly remains a clinical conundrum, given that age-related factors could alter the risk-benefit ratio of statin treatment. This study aimed to critically evaluate the efficacy and safety of statins for primary prevention of cardiovascular disease (CVD) in the elderly.

METHODS

We systematically reviewed randomized controlled trials comparing any statins with placebo or usual care for primary prevention of CVD in subjects aged ≥65 years. Relative risks (RRs) using a random effects model were calculated and sensitivity analyses were performed to assess the robustness of findings.

RESULTS

Eight studies (n = 25,952) were included in the meta-analysis. Statins significantly reduced the risks of composite major adverse cardiovascular events (RR 0.82, 95% CI 0.74-0.92), nonfatal myocardial infarction [MI] (0.75, 0.59-0.94) and total MI (0.74, 0.61-0.90). Treatment effects of statins were statistically insignificant in fatal MI (0.43, 0.09-2.01), stroke (fatal: 0.76, 0.24-2.45; nonfatal: 0.76, 0.53-1.11; total: 0.85, 0.68-1.06) and all-cause mortality (0.96, 0.88-1.04). Significant differences were not observed in myalgia (0.88, 0.69-1.13), elevation of hepatic transaminases (0.98, 0.71-1.34), new-onset diabetes (1.07, 0.77-1.48), serious adverse events (1.00, 0.97-1.04) and discontinuation due to adverse events (1.10, 0.85-1.42). The occurrence of myopathy, rhabdomyolysis and cognitive impairment was largely unreported in the included trials.

CONCLUSIONS

From a risk-benefit perspective, there is a role of statins for the primary prevention of major adverse cardiovascular events in elderly patients. Further studies are needed to ascertain the benefits of statins on fatal MI, stroke and all-cause mortality.

Local delivery of controlled-release simvastatin to improve the biocompatibility of polyethylene terephthalate artificial ligaments for reconstruction of the anterior cruciate ligament

The Ligament Advanced Reinforcement System has recently been widely used as the primary graft of choice in anterior cruciate ligament (ACL) reconstruction. But the biological graft-bone healing still remains a problem. Previous studies have shown that simvastatin (SIM) stimulates bone formation. The objective of this study was to investigate whether surface coating with collagen containing low-dose SIM microsphere could enhance the surface biocompatibility of polyethylene terephthalate (PET) artificial ligaments to accelerate graft-to-bone healing. The in vitro studies demonstrated that bone marrow stromal cells on the collagen-coated PET scaffolds (COL/PET) and simvastatin/collagen-coated PET scaffolds (SIM/COL/PET) proliferated vigorously. Compared with the PET group and the COL/PET group, SIM could induce bone marrow stromal cells' osteoblastic differentiation, high alkaline phosphatase activity, more mineralization deposition, and more expression of osteoblast-related genes, such as osteocalcin, runt-related transcription factor 2, bone morphogenetic protein-2, and vascular endothelial growth factor, in the SIM/COL/PET group. In vivo, rabbits received ACL reconstruction with different scaffolds. Histological analysis demonstrated that graft-bone healing was significantly greater with angiogenesis and osteogenesis in the SIM/COL/PET group than the other groups. In addition, biomechanical testing at the eighth week demonstrated a significant increase in the ultimate failure load and stiffness in the SIM/COL/PET group. The low dose of SIM-sustained release from SIM/COL/PET promoted the graft-bone healing via its effect on both angiogenesis and osteogenesis. This study suggested that collagen containing low-dose SIM microsphere coating on the surface of PET artificial ligaments could be potentially applied for ACL reconstruction.

Biochemistry of Statins

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Elevated blood lipids may be a major risk factor for CVD. Due to consistent and robust association of higher low-density lipoprotein (LDL)-cholesterol levels with CVD across experimental and epidemiologic studies, therapeutic strategies to decrease risk have focused on LDL-cholesterol reduction as the primary goal. Current medication options for lipid-lowering therapy include statins, bile acid sequestrants, a cholesterol-absorption inhibitor, fibrates, nicotinic acid, and omega-3 fatty acids, which all have various mechanisms of action and pharmacokinetic properties. The most widely prescribed lipid-lowering agents are the HMG-CoA reductase inhibitors, or statins. Since their introduction in the 1980s, statins have emerged as the one of the best-selling medication classes to date, with numerous trials demonstrating powerful efficacy in preventing cardiovascular outcomes (Kapur and Musunuru, 2008 [1]). The statins are commonly used in the treatment of hypercholesterolemia and mixed hyperlipidemia. This chapter focuses on the biochemistry of statins including their structures, pharmacokinetics, and mechanism of actions as well as the potential adverse reactions linked to their clinical uses.

Combination of calcium sulfate and simvastatin-controlled release microspheres enhances bone repair in critical-sized rat calvarial bone defects

Most allogenic bone graft substitutes have only osteoconductive properties. Developing new strategies to improve the osteoinductive activity of bone graft substitutes is both critical and practical for clinical application. Previously, we developed novel simvastatin-encapsulating poly(lactic-co-glycolic acid) microspheres (SIM/PLGA) that slowly release simvastatin and enhance fracture healing. In this study, we combined SIM/PLGA with a rapidly absorbable calcium sulfate (CS) bone substitute and studied the effect on bone healing in critical-sized calvarial bone defects in a rat model. The cytotoxicity and cytocompatibility of this combination was tested in vitro using lactate dehydrogenase leakage and a cell attachment assay, respectively. Combination treatment with SIM/PLGA and the CS bone substitute had no cytotoxic effect on bone marrow stem cells. Compared with the control, cell adhesion was substantially enhanced following combination treatment with SIM/PLGA and the CS bone substitute. In vivo, implantation of the combination bone substitute promoted healing of critical-sized calvarial bone defects in rats; furthermore, production of bone morphogenetic protein-2 and neovascularization were enhanced in the area of the defect. In summary, the combination of SIM/PLGA and a CS bone substitute has osteoconductive and osteoinductive properties, indicating that it could be used for regeneration of bone in the clinical setting.

Development and Evaluation of Liquid and Solid Self-Emulsifying Drug Delivery Systems for Atorvastatin

The objective of this work was to design and characterize liquid and solid self-emulsifying drug delivery systems (SEDDS) for poorly soluble atorvastatin. To optimize the composition of liquid atorvastatin-SEDDS, solubility tests, pseudoternary phase diagrams, emulsification studies and other in vitro examinations (thermodynamic stability, droplet size and zeta potential analysis) were performed. Due to the disadvantages of liquid SEDDS (few choices for dosage forms, low stability and portability during the manufacturing process), attempts were also made to obtain solid SEDDS. Solid SEDDS were successfully obtained using the spray drying technique from two optimized liquid formulations, CF3 and OF2. Despite liquid SEDDS formulation, CF3 was characterized by lower turbidity, higher percentage transmittance and better self-emulsifying properties, and based on the in vitro dissolution study it can be concluded that better solubilization properties were exhibited by solid formulation OF2. Overall, the studies demonstrated the possibility of formulating liquid and solid SEEDS as promising carriers of atorvastatin. SEDDS, with their unique solubilization properties, provide the opportunity to deliver lipophilic drugs to the gastrointestinal tract in a solubilized state, avoiding dissolution—a restricting factor in absorption rate of BCS Class 2 drugs, including atorvastatin.

Simvastatin enhances Rho/actin/cell rigidity pathway contributing to mesenchymal stem cells' osteogenic differentiation

Recent studies have indicated that statins induce osteogenic differentiation both in vitro and in vivo. The molecular mechanism of statin-stimulated osteogenesis is unknown. Activation of RhoA signaling increases cytoskeletal tension, which plays a crucial role in the osteogenic differentiation of mesenchymal stem cells. We thus hypothesized that RhoA signaling is involved in simvastatin-induced osteogenesis in bone marrow mesenchymal stem cells. We found that although treatment with simvastatin shifts localization of RhoA protein from the membrane to the cytosol, the treatment still activates RhoA dose-dependently because it reduces the association with RhoGDIα. Simvastatin also increased the expression of osteogenic proteins, density of actin filament, the number of focal adhesions, and cellular tension. Furthermore, disrupting actin cytoskeleton or decreasing cell rigidity by using chemical agents reduced simvastatin-induced osteogenic differentiation. In vivo study also confirms that density of actin filament is increased in simvastatin-induced ectopic bone formation. Our study is the first to demonstrate that maintaining intact actin cytoskeletons and enhancing cell rigidity are crucial in simvastatin-induced osteogenesis. The results suggested that simvastatin, which is an osteoinductive factor and acts by increasing actin filament organization and cell rigidity combined with osteoconductive biomaterials, may benefit stem-cell-based bone regeneration.

Bone critical defect repair with poloxamine-cyclodextrin supramolecular gels

The aim of this study was to evaluate the osteoinductive capacity of a poloxamine (Tetronic(®) 908, T) and α-cyclodextrin (αCD) supramolecular gel (T-CD) as scaffold in a critical size defect in rat calvaria. The T-CD gel was evaluated solely and after being loaded with simvastatin (SV) and bone morphogenetic protein (BMP-2) separately and in combinations in order to reduce the doses of the active substances. Three doses of SV (7.5, 75, 750 μg) and two doses of BMP-2 (3 and 6 μg) were tested. The histology and histomorphometrical analysis showed improved bone repair with T-CD compared to T, probably due to better release control of both SV and BMP-2. In addition, as T-CD eroded more slowly than poloxamine alone, it remained longer in the defect site. Although synergism was not obtained with BMP-2 and SV, according to the observed regeneration of the defect, the dose of BMP-2 and SV can be reduced to 3 μg and 7.5 μg, respectively.

Marked differences in frequencies of statin therapy relevant SLCO1B1 variants and haplotypes between Roma and Hungarian populations

Background

SLCO1B1 polymorphisms are relevant in statin pharmacokinetics. Aim of this study was to investigate the genetic variability and haplotype profile of SLCO1B1 polymorphisms in Roma and Hungarian populations. Genotypes of 470 Roma and 442 Hungarian subjects for c.388A > G, c.521T > C and c.1498-1331T > C polymorphisms were determined by PCR-RFLP assay. Using these SNPs eight different haplotypes could be differentiated.

Results

Differences were found between Roma and Hungarians in SLCO1B1 388AA (24.5 vs. 45.5 %), GG (33.4 vs. 17.9 %) genotypes, AG + GG (75.5 vs. 54.5 %) carriers, in G allele frequency (0.545 vs. 0.362), respectively (p < 0.001). The most common SLCO1B1 haplotype was the ht8 (GTT) both in Roma (43.6 %) and in Hungarian (59.1 %) samples. The ht6 (GCT) was not present in Roma population samples Haplotype analyses showed striking differences between the Roma and Hungarian samples in ht4 (ATT, 37.2 % vs 20.8 %), ht5 (GCC, 1.15 % vs. 3.62 %) and ht8 (GTT, 43.6 % vs. 59.1 %) haplotypes (p < 0.01), respectively. Linkage disequilibrium analysis showed that the studied variants are in different linkage disequilibrium patterns depending on the ethnic origin.

Conclusions

Similarly to Caucasians the 388G is the minor allele in Hungarians, however, in Roma the 388A was found to be the minor allele contrary to Indians (India). The minor allele frequency of 521T > C and 1498-1331T > C SNPs are almost three times higher in Romas than in Indians (Singapore and Gujarati, respectively). Observed allele frequency for 1498-1331T > C polymorphism reflects the measured average European rates in Hungarians. The results can be applied in population specific treatment algorithms when developing effective programs for statin therapy.

Novel effects of simvastatin on uterine fibroid tumors: in vitro and patient-derived xenograft mouse model study

OBJECTIVE

Uterine leiomyomas represent a common gynecologic problem with no satisfactory long-term medical treatment. The purpose of this study is to examine the effects of simvastatin on uterine leiomyoma, both in vitro and in vivo.

STUDY DESIGN

This is a laboratory-based experimental study. For in vitro studies, we used human and rat leiomyoma cells. For in vivo studies, we used immunodeficient mice supplemented with estrogen/progesterone pellets xenografted with human leiomyoma tissue explant.

RESULTS

For in vitro studies, cells were treated with different concentrations of simvastatin for 48 hours. Simvastatin induced dose-dependent apoptosis in leiomyoma cells as measured by a fluorometric caspase-3 activity assay, and inhibited proliferation as demonstrated by an (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay (both were significant at 5 and 10 μM). In addition, simvastatin decreased Akt signaling pathway phosphorylation as examined using Western blot analysis. For in vivo studies, animals were treated for 28 days with simvastatin (20 μg/gm body weight/day) vs vehicle control. The treatment inhibited tumor growth as measured weekly using calipers and/ or ultrasound (P < .01). Finally, simvastatin decreased expression of the proliferation marker Ki67 in xenograft tumor tissue as examined by immunohistochemistry (P = .02).

CONCLUSION

Simvastatin can be a promising treatment for uterine leiomyoma. Further studies, including pharmacokinetic and drug delivery studies, are required.

The effect of simvastatin treatment on endothelial cell response to shear stress and tumor necrosis factor alpha stimulation

Background

Statin drugs are one of the most commonly prescribed pharmaceuticals by physicians. By blocking the rate-limiting step in the cholesterol biosynthesis pathway, statins inhibit cholesterol synthesis, which benefits patient health. However, since many other important cellular processes are regulated within this pathway, they may also be influenced by statin therapy. These pleiotropic effects of statins have not been fully investigated, but are believed to positively influence endothelial cells (ECs), which line the vasculature in a confluent monolayer. Few studies have considered the effect of blood flow on ECs and how this may augment EC response to statins.

Methods

In this study, the effect of statin treatment on ECs is investigated for cells stimulated with tumor necrosis factor alpha (TNF-α), an inflammatory cytokine that promotes an atheroprone endothelium. Additionally, ECs are exposed to a physiologically relevant wall shear stress (WSS) of 12.5 dynes/cm² using a three-dimensional tissue culture model to provide a realistic hemodynamic environment. ECs are analyzed for morphology using light microscopy as well as cytoskeletal structure and alignment using confocal microscopy. Statistical analysis is performed on the results using both the one-way analysis of variance with Bonferroni post-tests and the two-tailed t test.

Results

We have shown that statin treatment caused cells to adapt to a rounded, atheroprone morphology, with a significantly higher shape index. Oppositely, TNF-α stimulation caused cells to elongate to an atheroprotective morphology, with a significantly lower shape index. WSS and TNF-α were unable to reverse any statin-induced cell rounding or F-actin disruption.

Conclusion

Further work is therefore needed to determine why statin drugs cause cells to have an atheroprone morphology, but an atheroprotective genotype, and why TNF-α stimulation causes an atheroprotective morphology, but an atheroprone genotype. Despite the morphological changes due to statins or stimulation, ECs still respond to WSS. Understanding how statins influence ECs will allow for more targeted treatments for hypercholestemia and potentially other diseases.

Expression of OATP2B1 as determinant of drug effects in the microcompartment of the coronary artery

Clinical success of coronary drug-eluting stents (DES) is hampered by simultaneous reduction of smooth muscle cell (HCASMC) and endothelial cell proliferation due to unspecific cytotoxicity of currently used compounds. Previous in vitro data showing SMC-specific inhibition of proliferation suggested that statins may be suitable candidates for DES. It was aim of this study to further investigate statins as DES drug candidates to identify mechanisms contributing to their cell-selectivity. In vitro proliferation assays comparing the influence of various statins on HCASMC and endothelial cells confirmed that atorvastatin exhibits HCASMC-specificity. Due to similar expression levels of the drug target HMG-CoA reductase in both cell types, cellular accumulation of atorvastatin was assessed, revealing enhanced uptake in HCASMC most likely driven by significant expression of OATP2B1, a known uptake transporter for atorvastatin. In accordance with the finding that endogenous OATP2B1 influenced cellular accumulation in HCASMC we used this transporter as a tool to identify teniposide as new DES candidate drug with HCASMC-specific effects. We describe OATP2B1 as a determinant of pharmacokinetics in the coronary artery. Indeed, endogenously expressed OATP2B1 significantly influences the uptake of substrate drugs, thereby governing cell specificity. Screening of candidate drugs for interaction with OATP2B1 may be used to promote SMC-specificity.

Targeting geranylgeranylation reduces adrenal gland tumor burden in a murine model of prostate cancer metastasis

The isoprenoid biosynthetic pathway (IBP) is critical for providing substrates for the post-translational modification of proteins key in regulating malignant cell properties, including proliferation, invasion, and migration. Inhibitors of the IBP, including statins and nitrogenous bisphosphonates, are used clinically for the treatment of hypercholesterolemia and bone disease respectively. The statins work predominantly in the liver, while the nitrogenous bisphosphonates are highly sequestered to bone. Inhibition of the entire IBP is limited by organ specificity and side effects resulting from depletion of all isoprenoids. We have developed a novel compound, disodium [(6Z,11E,15E)-9-[bis(sodiooxy)phosphoryl]-17-hydroxy-2,6,12,16-tetramethyheptadeca-2,6,11,15-tetraen-9-yl]phosphonate (GGOHBP), which selectively targets geranylgeranyl diphosphate synthase, reducing post-translational protein geranylgeranylation. Intracardiac injection of luciferase-expressing human-derived 22Rv1 PCa cells into SCID mice resulted in tumor development in bone (100 %), adrenal glands (72 %), mesentery (22 %), liver (17 %), and the thoracic cavity (6 %). Three weeks after tumor inoculation, daily subcutaneous (SQ) injections of 1.5 mg/kg GGOHBP or the vehicle were given for one month. Dissected tumors revealed a reduction in adrenal gland tumors corresponding to a 54 % (P < 0.005) reduction in total adrenal gland tumor weight of the treated mice as compared to vehicle-treated controls. Western blot analysis of the harvested tissues showed a reduction in Rap1A geranylgeranylation in adrenal glands and mesenteric tumors of the treated mice while non-tumorous tissues and control mice showed no Rap1A alteration. Our findings detail a novel bisphosphonate compound capable of preferentially altering the IBP in tumor-burdened adrenal glands of a murine model of PCa metastasis.

Drug-drug interactions that interfere with statin metabolism

INTRODUCTION

Lipid-lowering drugs, especially hydroxymethylglutaryl-CoA reductase inhibitors (statins), are widely used in the treatment and prevention of atherosclerotic diseases. The benefits of statins are well documented. However, myotoxic side effects, which can sometimes be severe, including myopathy or rhabdomyolysis, have been associated with the use of statins. In some cases, this toxicity is associated with pharmacokinetic alterations. Potent inhibitors of CYP 3A4 significantly increase plasma concentrations of the active forms of simvastatin, lovastatin and atorvastatin. Fluvastatin is metabolized by CYP2C9, while pravastatin, rosuvastatin and pitavastatin are not susceptible to inhibition by any CYP.

AREAS COVERED

This review discusses the pharmacokinetic aspects of the drug-drug interaction with statins and genetic polymorphisms in CYPs, which are involved in the metabolism of statins, and highlights the importance of establishing a system utilizing electronic medical information practically to avoid adverse drug reactions.

EXPERT OPINION

An understanding of the mechanisms underlying statin interactions will help to minimize drug interactions and develop statins that are less prone to adverse interactions. Quantitatively analyzed information for the low-density lipoprotein cholesterol lowering effects of statin based on electronic medical records may be useful for avoiding the adverse effect of statins.

Primary prevention with lipid lowering drugs and long term risk of vascular events in older people: population based cohort study

OBJECTIVE

To determine the association between use of lipid lowering drugs (statin or fibrate) in older people with no known history of vascular events and long term risk of coronary heart disease and stroke

DESIGN

Ongoing prospective population based cohort study recruited in 1999-2000, with five face-to-face examinations.

SETTING

Random sample of community dwelling population aged 65 years and over, living in three French cities (Bordeaux, Dijon, Montpellier).

PARTICIPANTS

7484 men and women (63%) with mean age 73.9 years and no known history of vascular events at entry. Mean follow-up was 9.1 years.

MAIN OUTCOME MEASURES

Adjusted hazard ratios of coronary heart disease and stroke in baseline lipid lowering drug users compared with non-users, calculated using multivariable Cox proportional hazard models adjusted for numerous potential confounding factors. Hazard ratios were estimated for use of any lipid lowering drug and for statin and fibrate separately.

RESULTS

Lipid lowering drug users were at decreased risk of stroke compared with non-users (hazard ratio 0.66, 95% confidence interval 0.49 to 0.90); hazard ratios for stroke were similar for statin (0.68, 0.45 to 1.01) and fibrate (0.66, 0.44 to 0.98). No association was found between lipid lowering drug use and coronary heart disease (hazard ratio 1.12, 0.90 to 1.40). Analyses stratified by age, sex, body mass index, hypertension, systolic blood pressure, triglyceride concentrations, and propensity score did not show any effect modification by these variables, either for stroke or for coronary heart disease.

CONCLUSION

In a population based cohort of older people with no history of vascular events, use of statins or fibrates was associated with a 30% decrease in the incidence of stroke.

Intratracheal instillation of pravastatin for the treatment of murine allergic asthma: a lung-targeted approach to deliver statins

Systemic treatment with statins mitigates allergic airway inflammation, T_H2 cytokine production, epithelial mucus production, and airway hyperreactivity (AHR) in murine models of asthma. We hypothesized that pravastatin delivered intratracheally would be quantifiable in lung tissues using mass spectrometry, achieve high drug concentrations in the lung with minimal systemic absorption, and mitigate airway inflammation and structural changes induced by ovalbumin. Male BALB/c mice were sensitized to ovalbumin (OVA) over 4 weeks, then exposed to 1% OVA aerosol or filtered air (FA) over 2 weeks. Mice received intratracheal instillations of pravastatin before and after each OVA exposure (30 mg/kg). Ultra performance liquid chromatography – mass spectrometry was used to quantify plasma, lung, and bronchoalveolar lavage fluid (BALF) pravastatin concentration. Pravastatin was quantifiable in mouse plasma, lung tissue, and BALF (BALF > lung > plasma for OVA and FA groups). At these concentrations pravastatin inhibited airway goblet cell hyperplasia/metaplasia, and reduced BALF levels of cytokines TNFα and KC, but did not reduce BALF total leukocyte or eosinophil cell counts. While pravastatin did not mitigate AHR, it did inhibit airway hypersensitivity (AHS). In this proof-of-principle study, using novel mass spectrometry methods we show that pravastatin is quantifiable in tissues, achieves high levels in mouse lungs with minimal systemic absorption, and mitigates some pathological features of allergic asthma. Inhaled pravastatin may be beneficial for the treatment of asthma by having direct airway effects independent of a potent anti-inflammatory effect. Statins with greater lipophilicity may achieve better anti-inflammatory effects warranting further research.

Atorvastatin reduces long pentraxin 3 expression in vascular cells by inhibiting protein geranylgeranylation

BACKGROUND

The long pentraxin PTX3 is an acute-phase multi-functional protein that might play both positive and detrimental effects under different pathophysiological conditions. We previously showed that statins down-regulate the release of PTX3 in human endothelial cells (ECs). The present study investigated the mechanism mediating this effect, its occurrence in other cells involved in atherogenesis, and whether it takes place in experimental atherosclerosis.

METHODS AND RESULTS

We found that atorvastatin (1-5 μmol/L) decreased the production and release of PTX3 in human ECs through a post-transcriptional effect. Co-incubation with mevalonate or geranylgeranyl pyrophosphate prevented this effect. Direct blockade of geranylgeranyl transferase I by GGTI-286, treatment with the Rac inhibitor NSC23766 or silencing of the geranylgeranylated GTPase Rac2 by siRNA closely mimicked the action of atorvastatin. In contrast, inactivation of other geranylgeranylated proteins such as RhoA, RhoB, and RhoC or Rac1 did not affect PTX3 release. In addition, we found that atorvastatin also decreased PTX3 secretion in aortic SMCs through a mechanism likely dependent on protein geranylgeranylation, while no effect was observed in monocytes. Finally, we found that atherosclerotic lesions from cholesterol-fed rabbits treated with atorvastatin (2.5 mg/kg/day for 8 weeks) showed less immunoreactive PTX3 than lesions from control animals.

CONCLUSIONS

Results suggest that statins may interfere with PTX3 expression in vascular cells via inhibition of protein geranylgeranylation. Since PTX3 is increasingly regarded as an important mediator of the inflammatory response underlying atherosclerosis and its complications, these results highlight the need for further studies of the role of PTX3 and its potential pharmacological modulation in cardiovascular disease.

Genetic basis for developmental toxicity due to statin intake using embryonic stem cell differentiation model

The in utero environment is a key factor controlling the fate of the growing embryo. The deleterious effects of statins during the fetal development are still not very well understood. Data from animal studies and retrospective studies performed in pregnant women give conflicting reports. In this study, using in vitro differentiation model of embryonic stem cells, which mimic the differentiation process of the embryo, we have systematically exposed the cells to lipophilic statins, simvastatin, and atorvastatin at various doses and at critical times during differentiation. The analysis of key genes controlling the differentiation into ecto-, meso- and endodermal lineages was assessed by quantitative polymerase chain reaction. Our results show that genes of the mesodermal lineage were most sensitive to statins, leading to changes in the transcript levels of brachyury, Flk-1, Nkx2.5, and α/β-myosin heavy chain. In addition, changes to endodermal marker α-fetoprotein, along with ectodermal Nes and Neurofilament 200 kDa, imply that during early differentiation exposure to these drugs leads to altered signaling, which could translate to the congenital abnormalities seen in the heart and limbs.

Unconventional approaches to the prevention of cancer associated thrombosis

A number of strategies are currently under investigation to prevent venous thromboembolic events in cancer cohorts. Based on the efficacy of low molecular weight heparin in the treatment of thrombosis in cancer patients, a number of clinical studies have focused on evaluating the efficacy the low molecular weight heparins in the primary thromboprophylaxis setting. Further refinements in defining which cancer cohorts are at greatest risk of suffering thromboembolic events are under investigation such as clinical-laboratory risk scores and biomarkers such as tissue factor-bearing microparticles. However, alternative approaches to primary thromboprophylaxis beyond standard anticoagulants are also being evaluated in the clinic such anti-platelet agents, statins to reduce circulating tissue factor, and scheduled monitoring for venous thromboembolic events without pharmacologic thromboprophylaxis. In addition, clinical studies are underway to evaluate the antithrombotic efficacy of targeting extracellular protein disulfide isomerase with oral flavonoids (e.g. quercetin and isoquercetin). Emerging data regarding these unconventional approaches in the prevention of thromboembolic events in cancer patients is reviewed.

Effects of local simvastatin on periosteal distraction osteogenesis in rabbits

Our aim was to evaluate the effect of local simvastatin on the formation of new bone using a new design of periosteal distractor. The distractors were placed between the periosteum and bone at the inferior border of the mandible of 20 New Zealand rabbits. In the first group (n=10) simvastatin was applied locally to the distraction zone. The other 10 rabbits served as controls. The formation of new bone was evaluated with digital direct radiography, computed tomography (CT), and histomorphometric analyses. New bone formed in all rabbits, but more formed in the experimental group according to histomorphometric variables. However, other measurements did not differ significantly between the groups. The new design of the periosteal distraction device was successful in causing new bone to form. Local simvastatin made no significant contribution to the procedure.

Preparation, in-vitro and in-vivo evaluation of spray-dried ternary solid dispersion of biopharmaceutics classification system class II model drug

OBJECTIVES

The objective of this study was to investigate the impact of a novel spray-dried ternary solid dispersion (TSD) on the dissolution rate and bioavailability of a biopharmaceutics classification system (BCS) class II model drug, atorvastatin calcium trihydrate (ATC), and evaluate its in-vitro and in-vivo performance.

METHODS

TSD of ATC was prepared by spray-drying method employing ethanol/water solvent systems. The TSD formulations, composed of hydroxypropyl methylcellulose (HPMC E5) and nicotinamide, were optimized by rotatable central composite design. Physicochemical characterization along with dissolution, stability and pharmacokinetic study of optimized TSD was evaluated.

KEY FINDINGS

The optimized TSD was found to be amorphous with spherical shape morphology. It exhibited a fourfold increase in dissolution rate in comparison to ATC, with a considerable enhancement in oral bioavailability (relative bioavailability of 134.11%). Physicochemical characterization and dissolution study of optimized TSD at the end of stability studies clearly indicated that the stability of optimized TSD was due to hydrogen bonding between drug and HPMC E5 and nicotinamide. This bonding remained unaffected even under stressful conditions of high temperature and humidity.

CONCLUSION

The TSD exhibits a significant increase in dissolution rate, and for this reason should be useful as an efficacious tool to enhance the bioavailability of BCS class II drug molecule, ATC.