Comparative effects of lipid-lowering therapies

Association of cytochromes P450 3A4*22 and 3A5*3 genotypes and polymorphism with response to simvastatin in hypercholesterolemia patients

BACKGROUNDS

Inter-individual variability in response to statin was mainly due to genetic differences. This study aimed to investigate the association of CYP3A4*22 (rs35599367), CYP3A5*3 (rs776746) single nucleotide polymorphism (SNP) with response to simvastatin in hypercholesterolemia patients conducted at King Abdulaziz University hospital (KAUH) in Jeddah, Saudi Arabia.

PATIENTS AND METHODS

A total of 274 participants were registered in the current study. Hypercholesterolemic patients taking simvastatin 20 mg (n = 148) and control subjects (n = 126) were tested for rs35599367 and rs776746 genotypes using Custom Taqman ® Assay Probes. Response to simvastatin in these patients was assessed by determination of low density lipoprotein (LDL-C), total cholesterol (TC) and by measuring statin plasma levels using Liquid Chromatography-Mass Spectrometry (LC-MS).

RESULTS

None of the participants carried a homozygous CYP3A4*22 mutant genotype, while 12 (4.4%) individuals had a heterozygous genotype and 262 (95.6%) had a wild homozygous genotype. The CYP3A5*3 allele was detected in the homozygous mutant form in 16 (5.8%) individuals, while 74 (27.0%) individuals carried the heterozygous genotype and 184 (67.2%) carried the wildtype homozygous genotype. Of the patient group, 15 (11%) were classified as intermediate metabolizers (IMs) and 133 (89%) as extensive metabolizers (EMs). Plasma simvastatin concentrations for the combined CYP3A4/5 genotypes were significantly (P<0.05) higher in the IMs group than in the EMs group. TC and plasma LDL-C levels were also significantly (P<0.05) higher in IMs than in EMs.

CONCLUSION

The present study showed associations between CYP3A4*22 (rs35599367) and CYP3A5*3 (rs776746) SNP combination genotypes with response to statins in hypercholesterolemia. Patients who had either a mutant homozygous allele for CYP3A5*3 or mutant homozygous and heterozygous alleles for CYP3A4*22 showed increased response to lower TC and LDL-C levels.

Egyptian practical guidance in hypertriglyceridemia management 2021

Hypertriglyceridemia (HTG) is a very common, yet underappreciated problem in clinical practice. Elevated triglyceride (TG) levels are independently associated with atherosclerotic cardiovascular disease (ASCVD) risk. Furthermore, severe HTG may lead to acute pancreatitis. Although LDL-guided statin therapy has improved ASCVD outcomes, residual risk remains. Recent trials have demonstrated that management of high TG levels, in patients already on statin therapy, reduces the rate of major vascular events. Few guidelines were issued, providing important recommendations for HTG management strategies. The goal of treatment is to reduce the risk of ASCVD and acute pancreatitis. The management stands on lifestyle modification, detection of secondary causes of HTG and pharmacological therapy, when indicated. In this guidance we review the causes and classification of HTG and summarize the current methods for risk estimation, diagnosis and treatment. The present guidance provides a focused update on the management of HTG, outlined in a simple user-friendly format, with an emphasis on the latest available data.

LDL-cholesterol change and goal attainment following statin intensity titration among Asians in primary care: a retrospective cohort study

Background

Clinical trials have demonstrated that either initiating or up-titrating a statin dose substantially reduce Low-Density Lipoprotein-Cholesterol (LDL-C) levels. However, statin adherence in actual practice tends to be suboptimal, leading to diminished effectiveness. This study aims to use real-world data to determine the effect on LDL-C levels and LDL-C goal attainment rates, when selected statins are titrated in Asian patients.

Methods

A retrospective cohort study over a 5-year period, from April 2014 to March 2019 was conducted on a cohort of multi-ethnic adult Asian patients with clinical diagnosis of Dyslipidaemia in a primary care clinic in Singapore. The statins were classified into low-intensity (LI), moderate-intensity (MI) and high-intensity (HI) groups according to the 2018 American College of Cardiology and American Heart Association (ACC/AHA) Blood Cholesterol Guidelines. Patients were grouped into “No statin”, “Non-titrators” and “Titrators” cohorts based on prescribing patterns. For the “Titrators” cohort, the mean percentage change in LDL-C and absolute change in LDL-C goal attainment rates were computed for each permutation of statin intensity titration.

Results

Among the cohort of 11,499 patients, with a total of 266,762 visits, there were 1962 pairs of LDL-C values associated with a statin titration. Initiation of LI, MI and HI statin resulted in a lowering of LDL-C by 21.6% (95%CI = 18.9–24.3%), 28.9% (95%CI = 25.0–32.7%) and 25.2% (95%CI = 12.8–37.7%) respectively. These were comparatively lower than results from clinical trials (30 to 63%). The change of LDL-C levels due to up-titration, down-titration, and discontinuation were − 12.4% to − 28.9%, + 13.2% to + 24.6%, and + 18.1% to + 32.1% respectively. The improvement in LDL-C goal attainment ranged from 26.5% to 47.1% when statin intensity was up-titrated.

Conclusion

In this study based on real-world data of Asian patients in primary care, it was shown that although statin titration substantially affected LDL-C levels and LDL-C goal attainment rates, the magnitude was lower than results reported from clinical trials. These results should be taken into consideration and provide further insight to clinicians when making statin adjustment recommendations in order to achieve LDL-C targets in clinical practice, particularly for Asian populations.

Research Progress of Herbal Medicines on Drug Metabolizing Enzymes: Consideration Based on Toxicology

The clinical application of herbal medicines is increasing, but there is still a lack of comprehensive safety data and in-depth research into mechanisms of action. The composition of herbal medicines is complex, with each herb containing a variety of chemical components. Each of these components may affect the activity of metabolizing enzymes, which may lead to herb-drug interactions. It has been reported that the combined use of herbs and drugs can produce some unexpected interactions. Therefore, this study reviews the progress of research on safety issues caused by the effects of herbs on metabolizing enzymes with reference to six categories of drugs, including antithrombotic drugs, non-steroidal anti-inflammatory drugs, anti-diabetic drugs, statins lipid-lowering drugs, immunosuppressants, and antineoplastic drugs. Understanding the effects of herbs on the activity of metabolizing enzymes could help avoid the toxicity and adverse drug reactions resulting from the co-administration of herbs and drugs, and help doctors to reduce the risk of prescription incompatibility.

Role of PPARs in Progression of Anxiety: Literature Analysis and Signaling Pathways Reconstruction

Peroxisome proliferator-activated receptor (PPAR) group includes three isoforms encoded by PPARG, PPARA, and PPARD genes. High concentrations of PPARs are found in parts of the brain linked to anxiety development, including hippocampus and amygdala. Among three PPAR isoforms, PPARG demonstrates the highest expression in CNS, where it can be found in neurons, astrocytes, and glial cells. Herein, the highest PPARG expression occurs in amygdala. However, little is known considering possible connections between PPARs and anxiety behavior. We reviewed possible connections between PPARs and anxiety. We used the Pathway Studio software (Elsevier). Signal pathways were created according to previously developed algorithms. SNEA was performed in Pathway Studio. Current study revealed 14 PPAR-regulated proteins linked to anxiety. Possible mechanism of PPAR involvement in neuroinflammation protection is proposed. Signal pathway reconstruction and reviewing aimed to reveal possible connection between PPARG and CCK-ergic system was conducted. Said analysis revealed that PPARG-dependent regulation of MME and ACE peptidase expression may affect levels of nonhydrolysed, i.e., active CCK-4. Impairments in PPARG regulation and following MME and ACE peptidase expression impairments in amygdala may be the possible mechanism leading to pathological anxiety development, with brain CCK-4 accumulation being a key link. Literature data analysis and signal pathway reconstruction and reviewing revealed two possible mechanisms of peroxisome proliferator-activated receptors involvement in pathological anxiety: (1) cytokine expression and neuroinflammation mechanism and (2) regulation of peptidases targeted to anxiety-associated neuropeptides, primarily CCK-4, mechanism.

The Role of Structure and Biophysical Properties in the Pleiotropic Effects of Statins

Statins are a class of drugs used to lower low-density lipoprotein cholesterol and are amongst the most prescribed medications worldwide. Most statins work as a competitive inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR), but statin intolerance from pleiotropic effects have been proposed to arise from non-specific binding due to poor enzyme-ligand sensitivity. Yet, research into the physicochemical properties of statins, and their interactions with off-target sites, has not progressed much over the past few decades. Here, we present a concise perspective on the role of statins in lowering serum cholesterol levels, and how their reported interactions with phospholipid membranes offer a crucial insight into the mechanism of some of the more commonly observed pleiotropic effects of statin administration. Lipophilicity, which governs hepatoselectivity, is directly related to the molecular structure of statins, which dictates interaction with and transport through membranes. The structure of statins is therefore a clinically important consideration in the treatment of hypercholesterolaemia. This review integrates the recent biophysical studies of statins with the literature on the physiological effects and provides new insights into the mechanistic cause of statin pleiotropy, and prospective means of understanding the cholesterol-independent effects of statins.

Propensity Score Matching: The 'Devil is in the Details' Where More May Be Hidden than You Know

Propensity score matching has been used with increasing frequency in the analyses of non-prespecified subgroups of randomized clinical trials, and in retrospective analyses of clinical trial data sets, registries, observational studies, electronic medical record analyses, and more. The method attempts to adjust post hoc for recognized unbalanced factors at baseline such that the data once analyzed will hopefully approximate or indicate what a prospective randomized data set-the "gold standard" for comparing two or more therapies-would have shown. However, for practical limitations, propensity score matching cannot assess and balance all the factors that come into play in the clinical management of patients and that may be present in the circumstances of the study. Thus, propensity score matching analyses may omit, due to nonrecognition, the effects of several clinically important but not considered factors that can affect the outcomes of the analyses being reported, causing them to possibly be misleading, or hypothesis-generating at best. This review discusses this issue, using several specific examples, and is targeted at clinicians to make them aware of the limitations of such analyses when they apply their results to patients in their care.

Mechanisms of gastrointestinal microflora on drug metabolism in clinical practice

Considered as an essential "metabolic organ", intestinal microbiota plays a key role in human health and the predisposition to diseases. It is an aggregate genome of trillions of microorganisms residing in the human gastrointestinal tract. Since the 20th century, researches have showed that intestinal microbiome possesses a variety of metabolic activities that are able to modulate the fate of more than 30 approved drugs and immune checkpoint inhibitors. These drugs are transformed to bioactive, inactive, or toxic metabolites by microbial direct action or host-microbial co-metabolism. These metabolites are responsible for therapeutic effects exerted by these drugs or side effects induced by these drugs, even for death. In view of the significant effect on the drugs metabolism by the gut microbiota, it is pivotal for personalized medicine to explore additional drugs affected by gut microbiota and their involved strains for further making mechanism clear through suitable animal models. This review mainly focus on specific mechanisms involved, with reference to the current literature about drugs metabolism by related bacteria or its enzymes available.

KIF6 gene as a pharmacogenetic marker for lipid-lowering effect in statin treatment

INTRODUCTION

The therapeutic response to statins has a high interindividual variability with respect to reductions in plasma LDL-cholesterol (c-LDL) and increases in HDL cholesterol (c-HDL). Many studies suggest that there is a relationship between the rs20455 KIF6 gene variant (c.2155T> C, Trp719Arg) and a lower risk of cardiovascular disease in patients being treated with statins.

AIM

The aim of this study was to investigate whether or not the c.2155T> C KIF6 gene variant modulates the hypercholesteremic effects of treatment with simvastatin, atorvastatin, or rosuvastatin.

MATERIALS AND METHODS

This was a prospective, observational and multicenter study. Three hundred and forty-four patients who had not undergone prior lipid-lowering treatment were recruited. Simvastatin, atorvastatin or rosuvastatin were administered. Lipid profiles and multiple clinical and biochemical variables were assessed before and after treatment.

RESULTS

The c.2155T> C variant of the KIF6 gene was shown to influence physiological responses to treatment with simvastatin and atorvastatin. Patients who were homozygous for the c.2155T> C variant (CC genotype, ArgArg) had a 7.0% smaller reduction of LDL cholesterol levels (p = 0.015) in response to hypolipidemic treatment compared to patients with the TT (TrpTrp) or CT (TrpArg) genotype. After pharmacological treatment with rosuvastatin, patients carrying the genetic variant had an increase in c-HDL that was 21.9% lower compared to patients who did not carry the variant (p = 0.008).

CONCLUSION

Being a carrier of the c.2155T> C variant of the KIF6 gene negatively impacts patient responses to simvastatin, atorvastatin or rosuvastatin in terms of lipid lowering effect. Increasing the intensity of hypolipidemic therapy may be advisable for patients who are positive for the c.2155T> C variant.

The poor design of clinical trials of statins in oncology may explain their failure - Lessons for drug repurposing

Statins are widely used to treat hypercholesterolaemia. However, by inhibiting the production of mevalonate, they also reduce the production of several isoprenoids that are necessary for the function of small GTPase oncogenes such as Ras. As such, statins offer an attractive way to inhibit an "undruggable" target, suggesting that they may be usefully repurposed to treat cancer. However, despite numerous studies, there is still no consensus whether statins are useful in the oncology arena. Numerous preclinical studies have provided evidence justifying the evaluation of statins in cancer patients. Some retrospective studies of patients taking statins to control cholesterol have identified a reduced risk of cancer mortality. However, prospective clinical studies have mostly not been successful. We believe that this has occurred because many of the prospective clinical trials have been poorly designed. Many of these trials have failed to take into account some or all of the factors identified in preclinical studies that are likely to be necessary for statins to be efficacious. We suggest an improved trial design which takes these factors into account. Importantly, we suggest that the design of clinical trials of drugs which are being considered for repurposing should not assume it is appropriate to use them in the same way as they are used in their original indication. Rather, such trials deserve to be informed by preclinical studies that are comparable to those for any novel drug.

Increasing HDL-C levels with medication: current perspectives

PURPOSE OF REVIEW

To date, observational studies have repeatedly demonstrated an inverse association between HDL cholesterol (HDL-C) levels and cardiovascular outcomes. Although the efficacy of established HDL-modifying treatment strategies have been examined in multiple large-scale phase III trials, findings from these experimental studies conflict with the hypothesis that HDL-C levels are atheroprotective. In this review, we describe the trial evidence to date, and attempt to place these results in the broader context of recent hypotheses for the association between HDL-C levels and clinical outcomes.

RECENT FINDINGS

Both translational and genetic studies are in line with the hypothesis that HDL-C levels do not hold causal importance for cardiovascular risk reduction. In addition to its possible role as a biomarker for other atherogenic lipoproteins, efforts should be made to elucidate HDLs' role in lipoprotein flux, which is increasingly being linked to surrogate outcomes of importance to cardiovascular epidemiology. In the future, it will be of great importance to link this measure of HDL functionality to clinical endpoints.

SUMMARY

Although trial evidence does not support an atheroprotective role of overall HDL-C plasma levels, HDL function/lipoprotein flux holds great promise for the development of novel therapeutic approaches.

Meta-analysis of genome-wide association studies of HDL cholesterol response to statins

BACKGROUND

In addition to lowering low density lipoprotein cholesterol (LDL-C), statin therapy also raises high density lipoprotein cholesterol (HDL-C) levels. Inter-individual variation in HDL-C response to statins may be partially explained by genetic variation.

METHODS AND RESULTS

We performed a meta-analysis of genome-wide association studies (GWAS) to identify variants with an effect on statin-induced high density lipoprotein cholesterol (HDL-C) changes. The 123 most promising signals with p<1×10-4 from the 16 769 statin-treated participants in the first analysis stage were followed up in an independent group of 10 951 statin-treated individuals, providing a total sample size of 27 720 individuals. The only associations of genome-wide significance (p<5×10-8) were between minor alleles at the CETP locus and greater HDL-C response to statin treatment.

CONCLUSIONS

Based on results from this study that included a relatively large sample size, we suggest that CETP may be the only detectable locus with common genetic variants that influence HDL-C response to statins substantially in individuals of European descent. Although CETP is known to be associated with HDL-C, we provide evidence that this pharmacogenetic effect is independent of its association with baseline HDL-C levels.

Rooted in risk: genetic predisposition for low-density lipoprotein cholesterol level associates with diminished low-density lipoprotein cholesterol response to statin treatment

AIMS

To utilize previously reported lead SNPs for low-density lipoprotein cholesterol (LDL-c) levels to find additional loci of importance to statin response, and examine whether genetic predisposition to LDL-c levels associates with differential statin response.

METHODS

We investigated effects on statin response of 59 LDL-c SNPs, by combining summary level statistics from the Global Lipids Genetics and Genomic Investigation of Statin Therapy consortia.

RESULTS

Lead SNPs for APOE, SORT1 and NPC1L1 were associated with a decreased LDL-c response to statin treatment, as was overall genetic predisposition for increased LDL-c levels as quantified with 59 SNPs, with a 5.4% smaller statin response per standard deviation increase in genetically raised LDL-c levels.

CONCLUSION

Genetic predisposition for increased LDL-c level may decrease efficacy of statin therapy.

Altered microRNome Profiling in Statin-Induced HepG2 Cells: A Pilot Study Identifying Potential new Biomarkers Involved in Lipid-Lowering Treatment

PURPOSE

Statins are widely prescribed drugs to manage hypercholesterolemia. Despite they are considered effective lipid-lowering agents, significant inter-individual variability has been reported in relation to drug response. Among the reasons explaining this variation, genetic factors are known to partially contribute. Nonetheless, poor evidence exists regarding epigenetic factors involved.

METHODS

We investigated if atorvastatin can modulate the cholesterol related miR-33 family. Furthermore, we analyzed the microRNA expression profiles in HepG2 cells treated for 24 hours with atorvastatin or simvastatin using a microarray platform.

RESULTS

Our results indicate that atorvastatin does not influence the expression of the miR-33 family. In addition, microarray examination revealed that atorvastatin modulated thirteen miRs, whilst simvastatin only affected two miRs. All significantly modulated miRs after simvastastin therapy were also modulated by atorvastatin. In addition, four novel miRs with previously unreported functions were identified as statin-modulated.

CONCLUSION

We identified several novel miRs affected by statin treatment. Additional research is needed to determine the biological significance of differentially expressed miRs identified in statins-induced HepG2 cells.

Objectively-measured sedentary time and its association with markers of cardiometabolic health and fitness among cardiac rehabilitation graduates

BACKGROUND

Sedentary time is an independent risk factor for cardiometabolic disease and mortality. It is unknown how much time individuals with coronary artery disease spend being sedentary or how their sedentary time relates to markers of health. The objectives of this study were to: (a) quantify sedentary time in a post-cardiac rehabilitation (CR) population, and (b) assess association with cardiometabolic risk, independent of moderate-to-vigorous physical activity.

DESIGN

Cross-sectional.

METHODS

As part of a larger trial, 263 recent CR graduates (∼10 days post-CR, mean age 63.6 ± 9.3 years, 75% male) wore an ActiGraph GT3X accelerometer during waking hours (≥4 days, ≥10 hours/day) to quantify sedentary time (≤150 counts per minute). Spearman correlations were computed to assess relationships between sedentary time (adjusted for wear time) with markers of cardiometabolic health and fitness. Significant markers were examined using multiple linear regressions.

RESULTS

Participants spent an average of 8 hours/day sedentary (∼14 bouts/day). Sedentary time was negatively correlated with high-density lipoprotein and [Formula: see text]O2peak and positively correlated with triglycerides, body mass index and waist circumference. After adjusting for age, sex, medications and moderate-to-vigorous physical activity, hours/day of sedentary time remained significantly associated with log[Formula: see text]O2peak (β = -0.02, p = 0.001) and body mass index (β = 0.49, p = 0.02).

CONCLUSIONS

Findings suggest that even among a group of post-CR individuals who are already probably more active than patients who have not undergone CR, sedentary time remains high and is associated with poorer cardiorespiratory fitness, suggesting a possible new area of focus among CR programs.

A Comparison of Accelerometer Cut-Points among Individuals with Coronary Artery Disease

Background

Accurate assessment of physical activity among coronary artery disease patients is important for assessing adherence to interventions. The study compared moderate-to-vigorous physical intensity activity and relationships with cardiometabolic health/fitness indicators using accelerometer cut-points developed for coronary artery disease patients versus those developed in younger and middle-aged adults.

Methods

A total of 231 adults with coronary artery disease wore an Actigraph GT3X accelerometer for ≥4 days (≥10 hours/day). Moderate-to-vigorous intensity physical activity between cut-points was compared using Bland-Altman analyses. Partial spearman correlations assessed relationships between moderate-to-vigorous intensity physical activity from each cut-point with markers of cardiometabolic health and fitness while controlling for age and sex.

Results

Average time spent in bouts of moderate-to-vigorous intensity physical activity using coronary artery disease cut-points was significantly higher than the young (mean difference: 13.0±12.8 minutes/day) or middle-aged (17.0±15.2 minutes/day) cut-points. Young and middle-aged cut-points were more strongly correlated with body mass index, waist circumference and systolic blood pressure, while coronary artery disease cut-points had stronger relationships with triglycerides, high-density and low-density lipoproteins. All were similarly correlated with measures of fitness.

Conclusion

Researchers need to exert caution when deciding on which cut-points to apply to their population. Further work is needed to validate which cut-points provide a true reflection of moderate-to-vigorous intensity physical activity and to examine relationships among patients with varying fitness.

ESR1 polymorphisms and statin therapy: a sex-specific approach

Lipid-lowering therapy has shown a high degree of variability in clinical response and there is evidence that the variability in drug response between individuals is due to genetic factors. Thirteen single nucleotide polymorphisms (SNPs) within the ESR1 gene were evaluated with basal lipid and lipoprotein levels, as well as response to lipid-lowering therapy, in 495 hypercholesterolemic individuals of European descent receiving simvastatin or atorvastatin. Significant associations were detected between rs4870061 (P=0.040, corrected P-value (PC)=0.440), rs1801132 (P=0.002, PC=0.022) and the SNP rs3020314 (P=0.013, PC=0.143) with triglyceride (TG) baseline levels. The rs4870061 was also associated with high-density lipoprotein cholesterol (HDL-C) baseline levels (P=0.045, PC=0.495). Regarding statin efficacy, rs2234693 C/C was associated with greater HDL-C increase (P=0.037; PC=0.407) and rs3798577 T allele was associated with greater total cholesterol (TC) reduction (P=0.019; PC=0.209) and greater TG reduction (P=0.026; PC=0.286). These associations suggest that ESR1 polymorphisms are in part responsible for the TC, HDL-C and TG variation levels and this effect may be sex-specific.

PON1 polymorphisms are predictors of ability to attain HDL-C goals in statin-treated patients

OBJECTIVES

PON1 plays an important role in inhibiting LDL-C oxidation, which reduces atherosclerosis and cardiovascular disease. Elevated PON1 activity or levels may contribute to increased HDL-C levels, but controversy exists over the hypothesis that genetic variation in the PON1 gene locus modulates HDL-C levels and responses to statin treatment. Therefore, the objective of this study was to investigate the association between two polymorphisms in the PON1 gene and statin responses in a south Brazilian population.

DESIGN AND METHODS

The study population included 433 dyslipidemic patients who were prescribed statins. Total cholesterol, triglyceride, HDL-C and LDL-C levels were measured in these patients both before and after approximately 6months of treatment with simvastatin/atorvastatin. Genotypes were assessed by real-time PCR for two PON1 polymorphisms, Q192R (rs662) and L55M (rs854560).

RESULTS

Baseline lipid levels were not associated with Q192R or L55M polymorphisms. For the Q192R (rs662) polymorphism, we observed that HDL-C goals were attained less often in patients with RR homozygosity than in Q allele carriers (χ(2) P=0.009, adjusted residual analysis P=0.003). For the L55M (rs854560) polymorphism, LL homozygotes were underrepresented among subjects that achieved the HDL-C goal (χ(2) P=0.026, adjusted residual analysis P=0.008). Analysis by univariate logistic regression confirmed that QQ/QR and MM/ML carriers had an increased chance of attaining HDL-C goals (OR=2.41, CI95%=1.32-4.40, P=0.004 and OR=1.68, CI95%=1.15-2.45, P=0.008). In a multivariate logistic analysis used to assess predictors of attaining an HDL-C goal>1.55mmol/L, we observed that gender (OR=1.71, CI95%=1.04-2.83, P=0.036), baseline HDL-C levels (OR=1.13, CI95%=1.10-1.16, P<0.001) and the QQ/QR+MM/ML genotypes increased the chance of achieving HDL-C goals (OR=2.81, CI95%=1.35-5.85, P=0.006).

CONCLUSIONS

The results of this study show that the Q192R (rs662) and L55M (rs854560) polymorphisms may play a role in interindividual variation in achievement of HDL-C goals in response to statins.

Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins

Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response.

Attenuation of acetylcholine activated potassium current (I KACh) by simvastatin, not pravastatin in mouse atrial cardiomyocyte: possible atrial fibrillation preventing effects of statin

Statins, 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors, are associated with the prevention of atrial fibrillation (AF) by pleiotropic effects. Recent clinical trial studies have demonstrated conflicting results on anti-arrhythmia between lipophilic and hydrophilic statins. However, the underlying mechanisms responsible for anti-arrhythmogenic effects of statins are largely unexplored. In this study, we evaluated the different roles of lipophilic and hydrophilic statins (simvastatin and pravastatin, respectively) in acetylcholine (100 µM)-activated K⁺ current (I_KACh, recorded by nystatin-perforated whole cell patch clamp technique) which are important for AF initiation and maintenance in mouse atrial cardiomyocytes. Our results showed that simvastatin (1–10 µM) inhibited both peak and quasi-steady-state I_KACh in a dose-dependent manner. In contrast, pravastatin (10 µM) had no effect on I_KACh. Supplementation of substrates for the synthesis of cholesterol (mevalonate, geranylgeranyl pyrophosphate or farnesyl pyrophosphate) did not reverse the effect of simvastatin on I_KACh, suggesting a cholesterol-independent effect on I_KACh. Furthermore, supplementation of phosphatidylinositol 4,5-bisphosphate, extracellular perfusion of phospholipase C inhibitor or a protein kinase C (PKC) inhibitor had no effect on the inhibitory activity of simvastatin on I_KACh. Simvastatin also inhibits adenosine activated I_KACh, however, simvastatin does not inhibit I_KACh after activated by intracellular loading of GTP gamma S. Importantly, shortening of the action potential duration by acetylcholine was restored by simvastatin but not by pravastatin. Together, these findings demonstrate that lipophilic statins but not hydrophilic statins attenuate I_KACh in atrial cardiomyocytes via a mechanism that is independent of cholesterol synthesis or PKC pathway, but may be via the blockade of acetylcholine binding site. Our results may provide important background information for the use of statins in patients with AF.

Simvastatin attenuates the oxidative stress, endothelial thrombogenicity and the inducibility of atrial fibrillation in a rat model of ischemic heart failure

Increased atrial oxidative stress has an important role in inducing and maintaining atrial fibrillation (AF), and the activation of the small GTPase Rac1 contributes to the oxidative stress. We investigated the relationship of Rac1, atrial endothelial thromboprotective markers and AF inducibility and if simvastatin has a potential beneficial effect on a myocardial infarction (MI)-induced heart failure (HF) rat model. Rats were randomized into three groups (shams, MI group and simvastatin treatment group) and underwent echocardiography, AF induction studies and left atrial (LA) fibrosis analysis. Atrial Rac 1, sodium calcium exchanger (I_NCX), sarcoplasmic reticulum calcium ATPase (SERCA), endothelial nitric oxide synthase (eNOS) and induced nitric oxide synthase (iNOS) were measured. AF inducibility, AF duration and LA fibrosis were significantly higher in the MI group (p < 0.001 vs. sham), which were significantly reduced by simvastatin (p < 0.05 vs. MI). The reduced expressions of atrial eNOS, SERCA, thrombomodulin, tissue factor pathway inhibitor and tissue plasminogen activator in the MI group were significantly improved by simvastatin. Furthermore, the increased expression of atrial iNOS, I_NCX and Rac1 activity were significantly decreased by the simvastatin. Oxidative stress, endothelial dysfunction and thrombogenicity are associated with the promotion of AF in a rat model of ischemic HF. These were associated with increased Rac1 activity, and simvastatin treatment prevents these changes.

Predicting individual responses to pravastatin using a physiologically based kinetic model for plasma cholesterol concentrations

We used a previously developed physiologically based kinetic (PBK) model to analyze the effect of individual variations in metabolism and transport of cholesterol on pravastatin response. The PBK model is based on kinetic expressions for 21 reactions that interconnect eight different body cholesterol pools including plasma HDL and non-HDL cholesterol. A pravastatin pharmacokinetic model was constructed and the simulated hepatic pravastatin concentration was used to modulate the reaction rate constant of hepatic free cholesterol synthesis in the PBK model. The integrated model was then used to predict plasma cholesterol concentrations as a function of pravastatin dose. Predicted versus observed values at 40 mg/d pravastatin were 15 versus 22 % reduction of total plasma cholesterol, and 10 versus 5.6 % increase of HDL cholesterol. A population of 7,609 virtual subjects was generated using a Monte Carlo approach, and the response to a 40 mg/d pravastatin dose was simulated for each subject. Linear regression analysis of the pravastatin response in this virtual population showed that hepatic and peripheral cholesterol synthesis had the largest regression coefficients for the non-HDL-C response. However, the modeling also showed that these processes alone did not suffice to predict non-HDL-C response to pravastatin, contradicting the hypothesis that people with high cholesterol synthesis rates are good statin responders. In conclusion, we have developed a PBK model that is able to accurately describe the effect of pravastatin treatment on plasma cholesterol concentrations and can be used to provide insight in the mechanisms behind individual variation in statin response.

In search for genetic determinants of clinically meaningful differential cardiovascular event reduction by pravastatin in the PHArmacogenetic study of Statins in the Elderly at risk (PHASE)/PROSPER study

BACKGROUND

Statin therapy is widely used in the prevention and treatment of cardiovascular events and is associated with significant risk reductions. However, there is considerable variation in response to statin therapy both in terms of LDL cholesterol reduction and clinical outcomes. It has been hypothesized that genetic variation contributes importantly to this individual drug response.

METHODS AND RESULTS

We investigated the interaction between genetic variants and pravastatin or placebo therapy on the incidence of cardiovascular events by performing a genome-wide association study in the participants of the PROspective Study of Pravastatin in the Elderly at Risk for vascular disease--PHArmacogenetic study of Statins in the Elderly at risk (PROSPER/PHASE) study (n = 5244). We did not observe genome-wide significant associations with a clinically meaningful differential cardiovascular event reduction by pravastatin therapy. In addition, SNPs with p-values lower than 1 × 10(-4) were assessed for replication in a case-only analysis within two randomized placebo controlled pravastatin trials, CARE (n = 711) and WOSCOPS (n = 522). rs7102569, on chromosome 11 near the ODZ4 gene, was replicated in the CARE study (p = 0.008), however the direction of effect was opposite. This SNP was not associated in WOSCOPS. In addition, none of the SNPs replicated significantly after correcting for multiple testing.

CONCLUSIONS

We could not identify genetic variation that was significantly associated at genome-wide level with a clinically meaningful differential event reduction by pravastatin treatment in a large prospective study. We therefore assume that in daily practice the use of genetic characteristics to personalize pravastatin treatment to improve prevention of cardiovascular disease will be limited.

Improved glycemic control and lipid profile in hyperlipidemic type 2 diabetic patients consuming Salvia officinalis L. leaf extract: a randomized placebo. Controlled clinical trial

OBJECTIVES

Evaluation of the efficacy and safety of Salvia officinalis L. (S. officinalis) leaf extract in the treatment of hyperlipidemic type 2 diabetic patients.

DESIGN

Randomized placebo-controlled parallel group study.

SETTING

Diabetes Clinic (Karaj City, Alborz Province of Iran).

INTERVENTIONS

The efficacy and safety of taking S. officinalis leaf extract (one 500 mg capsule t.i.d. for 3 months) in treatment of 40 hyperlipidemic (hypercholesterolemic and/or hypertriglyceridemic) type 2 diabetic patients were evaluated and compared with the placebo group (n=40).

MAIN OUTCOME MEASURES

Fasting blood levels of glucose, glycosylated hemoglobin (HbA1c), total cholesterol, triglyceride, LDL-C (low density lipoprotein cholesterol), HDL-C (high density lipoprotein cholesterol), SGOT (serum glutamic-oxaloacetic transaminase), SGPT (serum glutamic-pyruvic transaminase) and creatinine.

RESULTS

The extract lowered fasting glucose, HbA1c, total cholesterol, triglyceride and LDL-C but increased HDL-C compared to baseline at endpoint. Percent difference mean (95% confidence interval) between the extract and placebo groups in terms of effects on fasting glucose, HbA1c, total cholesterol, triglyceride, LDL-C and HDL-C at endpoint were 32.2 (26.5, 37.9), 22.7 (16.8, 28.6), 16.9 (9.7, 24.1), 56.4 (36.1, 76.7), 35.6 (29.9, 41.3) and 27.6 (15.8, 39.4) (P=0.001, P=0.01, P=0.01, P=0.009, P<0.001 and P=0.008), respectively. Moreover, the extract did not have any significant effects on the other parameters compared to the placebo group at endpoint (P>0.05). No adverse effects were reported.

CONCLUSIONS

S. officinalis leaves may be safe and have anti-hyperglycemic and lipid profile improving effects in hyperlipidemic type 2 diabetic patients.

Improved lipid profile in hyperlipidemic patients taking Vaccinium arctostaphylos fruit hydroalcoholic extract: a randomized double-blind placebo-controlled clinical trial

Dyslipidemia is a common contributory cause of cardiovascular disease. Vaccinium arctostaphylos L. (Caucasian whortleberry) fruit is rich of anthocyanins. Anthocyanins may exert cardioprotective effects by various mechanisms such as favorably modulating dyslipidemia. Therefore, in this randomized double-blind placebo-controlled clinical trial with hyperlipidemic (hypercholesterolemic and/or hypertriglyceridemic) patients aged 20-60 years, the effects of taking a standardized whortleberry fruit hydroalcoholic extract (one 350 mg capsule every 8 h for 2 months) on fasting blood levels of lipids, creatinine and liver enzymes including SGOT and SGPT were evaluated in 40 patients and compared with the placebo group (n = 40). The extract lowered the blood levels of total cholesterol (P < 0.001), triglyceride (P = 0.002) and low-density lipoprotein cholesterol (LDL-C) (P = 0.002), but increased the blood high-density lipoprotein cholesterol (HDL-C) levels (P < 0.001) without any significant effects on the blood levels of SGOT, SGPT and creatinine (P > 0.05) compared with the placebo group at the endpoint. Whortleberry reduced total cholesterol, triglyceride and LDL-C 27.6%, 19.2% and 26.3%, respectively, but increased HDL-C 37.5% compared with baseline. No adverse effects were reported. Short-term treatment with whortleberry fruit appears safe and improves lipid profile in hyperlipidemic patients.

Impact of artificial plaque composition on drug transport

Drug-eluting stent (DES) implantation is a common treatment for atherosclerosis. The safety and efficacy of these devices will depend on the uptake and distribution of drug into the vessel wall. It is established that the composition of atherosclerotic vessels can vary dramatically with patients' age and gender. However, studies focused on elucidating and quantifying the impact of these variations on important drug transport properties, such as diffusion (D) and partition (k) coefficients, are limited. We have developed an improved tissue mimic or artificial plaque to probe the effect of varying concentrations of plaque constituents on drug transport in vitro. Based on these artificial plaques, we have quantified the impact of gelatin (hydrolyzed collagen) and lipid (cholesterol) concentration on D and k using two model drugs, tetracycline and fluvastatin. We found that for tetracycline, increasing the collagen concentration from 0.025 to 0.100 (w/w) resulted in a fivefold decrease in diffusivity, whereas there was no discernible impact on solubility. Increasing the lipid concentration up to 0.034 (w/w) resulted in only minor changes to transport properties of tetracycline. However, fluvastatin exhibited nearly a fivefold increase in k and 10-fold decrease in D with increased lipid concentration. These results were in reasonable agreement with existing models and exhibited behavior consistent with previous observations on drugs commonly used in DES applications. These observations suggest that variations in the chemical characteristics of atherosclerotic plaque can significantly alter the release rate and distribution of drug following DES implantation.

Acompanhamento farmacoterapêutico em pacientes dislipidêmicos de um lar de idosos da cidade de Novo Hamburgo-RS

INTRODUÇÃO: A partir do último século, observou-se aumento na expectativa de vida e na incidência de patologia na população idosa, principalmente doenças crônicas. OBJETIVO: Avaliar o efeito do acompanhamento farmacoterapêutico (AF) em pacientes dislipidêmicos de um lar de idosos da cidade de Novo Hamburgo, RS. METODOLOGIA: Trata-se de estudo quantitativo, observacional com delineamento longitudinal retrospectivo, que avaliou 50 pacientes idosos residentes de um lar geriátrico (80,2 ± 7,64 anos, 32 mulheres). Foi avaliado o perfil lipídico desses pacientes (colesterol total, triglicerídeos, HDL e LDL) antes e após AF de um ano. A análise dos resultados ocorreu por meio de estatística descritiva e teste t Student ou U de Mann Whitney para amostras pareadas. RESULTADOS: 56% dos pacientes apresentaram alteração no perfil lipídico no início do estudo e, 30% ao final, ocorrendo significativa melhora após o AF. Além disso, os níveis de colesterol total apresentaram diminuição favorável após um ano de acompanhamento (206 ± 53 vs. 180 ± 43 mg/dL; P = 0,009). A maioria dos pacientes que apresentou diagnóstico de dislipidemia utilizava medicamentos há pelo menos três meses para o tratamento dessa patologia (estatinas e fibratos). A maioria desses pacientes utilizava os medicamentos de forma correta. CONCLUSÃO: Conclui-se que os pacientes tiveram melhora no seu perfil lipídico após um ano de acompanhamento.

Pharmacogenetics of statins: achievements, whole-genome analyses and future perspectives

Statins are the most commonly prescribed class of drug worldwide and therapy is highly effective in reducing low-density lipoprotein cholesterol levels and cardiovascular events. However, there is large variability in clinical response to statin treatment. Recent research provides evidence that genetic variation contributes to this variable response to statin treatment. Until recently, pharmacogenetic studies have used mainly candidate gene approaches to investigate these effects. Since candidate gene studies explain only a small part of the observed variation and results have often been inconsistent, genome-wide association (GWA) studies may be a better approach. In this paper the most important candidate gene studies and the first published GWA studies assessing statin response are discussed. Moreover, we describe the PHASE study, an EU-funded GWA study that will investigate the genetic variation responsible for the variation in response to pravastatin in a large randomized clinical trial.

Protective effect of Tulbaghia violacea Harv. on aortic pathology, tissue antioxidant enzymes and liver damage in diet-induced atherosclerotic rats

The protective effect Tulbaghia violacea rhizomes (TVR) against derangements in serum lipid profile, tissue antioxidant enzyme depletion, endothelium dysfunction and histopathological changes in the aorta and liver of rats fed with an atherosclerogenic (Ath) diet (4% cholesterol, 1% cholic acid and 0.5% thiouracil) was investigated in this study. Co-treatment with the TVR extracts (250 and 500 mg/kg body weight for two weeks significantly (p < 0.05) protected against elevated serum triglyceride (TG), total cholesterol (TC), LDL-cholesterol, VLDL-cholesterol and decreased HDL-cholesterol in a dose-dependent manner when compared with the atherogenic control. The extracts also reduced (p < 0.05) elevated thiobabutric reacting substance (TBARS) and reversed endothelial dysfunction parameters (fibrinogen and total NO levels) and tissue antioxidant enzyme activities to near normal. The protective ability of the extract was confirmed by the significant (p < 0.05) reduction in the activities of serum markers of liver (LDH, AST, ALT, ALP, bilirubin) and kidney damage (creatinine and bilirubin) in extract-treated groups compared with the atherogenic control group. Also, histopathology evaluations of aorta sections revealed that the extracts protected against the development of fatty streak plaques (aorta) and fatty changes in hepatocytes. The observed activities of the extracts compared favorably with standard drug atorvastatin. Our study thus showed that the methanolic extract of TVR could protect against the early onset of atherosclerosis.

A physiologically based in silico kinetic model predicting plasma cholesterol concentrations in humans

Increased plasma cholesterol concentration is associated with increased risk of cardiovascular disease. This study describes the development, validation, and analysis of a physiologically based kinetic (PBK) model for the prediction of plasma cholesterol concentrations in humans. This model was directly adapted from a PBK model for mice by incorporation of the reaction catalyzed by cholesterol ester transfer protein and contained 21 biochemical reactions and eight different cholesterol pools. The model was calibrated using published data for humans and validated by comparing model predictions on plasma cholesterol levels of subjects with 10 different genetic mutations (including familial hypercholesterolemia and Smith-Lemli-Opitz syndrome) with experimental data. Average model predictions on total cholesterol were accurate within 36% of the experimental data, which was within the experimental margin. Sensitivity analysis of the model indicated that the HDL cholesterol (HDL-C) concentration was mainly dependent on hepatic transport of cholesterol to HDL, cholesterol ester transfer from HDL to non-HDL, and hepatic uptake of cholesterol from non-HDL-C. Thus, the presented PBK model is a valid tool to predict the effect of genetic mutations on cholesterol concentrations, opening the way for future studies on the effect of different drugs on cholesterol levels in various subpopulations in silico.

Simultaneous Determination of Atorvastatin and Aspirin in Human Plasma by LC-MS/MS: Its Pharmacokinetic Application

A simple, rapid, and sensitive liquid chromatography tandem mass spectro-metric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin and aspirin in human plasma using a polarity switch. Proguanil and furosemide were used as the internal standards for the quantification of atorvastatin and aspirin, respectively. The analytes were extracted from human plasma by the liquid-liquid extraction technique using methyl tert-butyl ether. The reconstituted samples were chromatographed on a Zorbax XDB Phenyl column by using a mixture of 0.2% acetic acid buffer, methanol, and acetonitrile (20:16:64, v/v) as the mobile phase at a flow rate of 0.8 mL/min. Prior to detection, atorvastatin and aspirin were ionized using an ESI source in the multiple reaction monitoring (MRM) mode. The ions were monitored at the positive m/z 559.2→440.0 transition for atorvastatin and the negative m/z 179.0→136.6 transition for aspirin. The calibration curve obtained was linear (r(2) ≥ 0.99) over the concentration range of 0.20-151 ng/mL for atorvastatin and 15.0-3000 ng/mL for aspirin. The method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 3.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The proposed method was found to be applicable to clinical studies.

High performance liquid chromatography mass spectrometric method for the simultaneous quantification of pravastatin and aspirin in human plasma: Pharmacokinetic application

A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma. Furosemide was used as an internal standard. Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether. The reconstituted samples were chromatographed on a Zorbax SB-C18 column by using a mixture of 5 mM ammonium acetate buffer and acetonitrile (20:80, v/v) as the mobile phase at a flow rate of 0.8 mL/min. The calibration curve obtained was linear (r≥0.99) over the concentration range of 0.50-600.29 ng/mL for pravastatin and 20.07-2012.00 ng/mL for aspirin. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day. The proposed method was found to be applicable to clinical studies.

Salutary effect of Cassia auriculata L. Leaves on hyperglycemia-induced atherosclerotic environment in streptozotocin rats

Diabetes mellitus is very often associated with dyslipidemia, increased oxidative stress and endothelial dysfunction that could develop atherosclerosis and consequently cardiovascular diseases. Medicinal plants with reputed traditional use to treat diabetes and cardiovascular diseases might provide valuable drugs. Therefore, the present study was designed to evaluate anti-atherosclerotic potential of aqueous extract of Cassia auriculata L. leaves in streptozotocin (STZ)-induced diabetic rats. The rats were rendered diabetic by STZ (45 mg/kg, ip). Diabetic rats were orally administered C. auriculata leaf extract at 400 mg/kg dose daily for 21 days. The supplementation of extract to the diabetic rats produced significant reduction in fasting blood glucose along with significant reversal in altered serum lipid profile and apolipoprotein B. Lipid peroxidation was found to be significantly suppressed in extract-fed diabetic rats. The significant reduction in serum levels of oxidized low-density lipoprotein, soluble vascular cell adhesion molecule and plasma fibrinogen with a concomitant elevation in serum nitric oxide was observed in diabetic rats following treatment with extract. Histopathological examination of heart myocardium of extract-treated diabetic rats revealed reversal of fatty change toward normal. These results suggest that C. auriculata aqueous leaf extract exhibits anti-atherosclerotic role in the diabetic state and it indicates toward the notion that extract may help to prevent the progression of cardiovascular diseases.

Simultaneous determination of simvastatin, lovastatin and niacin in human plasma by LC-MS/MS and its application to a human pharmacokinetic study

A simple, sensitive and specific LC-MS/MS method for simultaneous determination of simvastatin (SV), lovastatin (LV) and niacin (NIA) in human plasma was developed and validated on API-4000 in positive ion mode. Nevirapine was used as internal standard (IS). The assay procedure involved a simple one-step liquid-liquid extraction of SV, LV, NIA and the IS from plasma into ethyl acetate. Separation of SV, LV, NIA and the IS was achieved on an Alltima C₁₈ column with a mobile phase consisting of 5 mm ammonium acetate (pH 4.5) and acetonitrile (20:80, v/v) pumped at a flow rate of 1 mL/min. Nominal retention times obtained for SV, LV, NIA and IS were 2.12, 1.67, 0.50 and 0.65 min, respectively. The lower limits of quantification (LLOQ) for SV, LV and NIA were 0.10, 0.10 and 25.2 ng/mL, respectively. The response function was established for the range of concentrations 0.10-101 ng/mL for SV and LV, and 25.2-5020 ng/mL for NIA, with a coefficient of correlation of >0.99 for all the compounds. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The proposed method was found to be applicable to clinical studies.

Antihyperlipidemic effects of Salvia officinalis L. leaf extract in patients with hyperlipidemia: a randomized double-blind placebo-controlled clinical trial

Hyperlipidemia is a common metabolic disorder contributing to morbidities and mortalities due to cardiovascular and cerebrovascular diseases. Conventional antihyperlipidemic drugs have limited efficacies and important side effects, so that alternative lipid lowering agents are needed. Salvia officinalis L. (sage) leaves have PPAR γ agonistic, pancreatic lipase and lipid absorption inhibitory, antioxidant, lipid peroxidation inhibitory and antiinflammatory effects. Thus, in this randomized double-blind placebo-controlled clinical trial with 67 hyperlipidemic (hypercholesterolemic and/or hypertriglyceridemic) patients aged 56.4 ± 30.3 years (mean ± SD), the effects of taking sage leaf extract (one 500 mg capsule every 8 h for 2 months) on fasting blood levels of lipids, creatinine and liver enzymes including SGOT and SGPT were evaluated in 34 patients and compared with the placebo group (n = 33). The extract lowered the blood levels of total cholesterol (p < 0.001), triglyceride (p = 0.001), LDL (p = 0.004) and VLDL (p = 0.001), but increased the blood HDL levels (p < 0.001) without any significant effects on the blood levels of SGOT, SGPT and creatinine (p > 0.05) compared with the placebo group at the endpoint. No adverse effects were reported. The results suggest that sage may be effective and safe in the treatment of hyperlipidemia.

Synthesis, characterization and in vitro hydrolysis of a gemfibrozil-nicotinic acid codrug for improvement of lipid profile

Combination therapy of fibrates and nicotinic acid has been reported to be synergistic. Herein, we describe a covalent codrug of gemfibrozil (GEM) and nicotinic acid (NA) that was synthesized and characterized by (1)H NMR, (13)C NMR, FT-IR, MS analysis and elemental analysis. A validated HPLC method was developed that allows for the accurate quantitative determination of the codrug and its hydrolytic products that are formed during the in vitro chemical and enzymatic hydrolysis. The physico-chemical properties of codrug were improved compared to its parent drugs in term of water solubility and partition coefficient. The kinetics of hydrolysis of the codrug was studied using accelerated hydrolysis experiments at high temperatures in aqueous phosphate buffer solution in pH 1.2, 6.8 and 7.4. Using the Arrhenius equation, the extrapolated half-life at 37°C were 289 days at pH 1.2 for the codrug and 130 and 20,315 days at pH 6.8 for the codrug and gemfibrozil 2-hydroxyethyl ester (GHEE), respectively. The shortest half-lives were at pH 7.4; 42 days for the codrug and 5837 days for GHEE, respectively. The hydrolysis of the latter was studied, alone, at 80°C and pH 1.2 and compared to its hydrolysis when it is produced from the codrug using similar conditions. The k(obs) was found in both cases to be 1.60×10(-3)h(-1). The half-lives in plasma were 35.24 min and 26.75 h for the codrug and GHEE, respectively. With regard to liver homogenate, the hydrolysis half-lives were 1.96 min and 48.13 min for the codrug and GHEE, respectively. It can be expected that in vivo, the codrug will liberate NA immediately in plasma then GEM will be liberated from its 2-hydroxyethyl ester in the liver.

Drug treatment of hyperlipidaemia: a guide to the rational use of lipid-lowering drugs

Mammalian sterol and lipid metabolism depends on a large number of highly evolved biochemical and histological processes responsible for the absorption, distribution and steady-state anabolic/catabolic handling of these substances. Lipoproteins are complex polymolecular assemblies comprising phospholipids, cholesterol and cholesterol esters, triglycerides and a variety of apolipoproteins. The primary function of lipoproteins is to facilitate the systemic distribution of sterols and lipids. Abnormalities in lipoprotein metabolism are quite common and are attributable to a large number of genetic mutations, metabolic derangements such as insulin resistance or thyroid dysfunction, and excess availability of cholesterol and fat from dietary sources. Dyslipidaemic states facilitate endothelial dysfunction and atherogenesis. Dyslipidaemia is recognized as a risk factor for cardiovascular disease in both men and women, and people of all racial and ethnic groups throughout the world. Dyslipidaemia is modifiable with dietary change and the use of medications that impact on lipid metabolism through a variety of mechanisms. Reducing atherogenic lipoprotein burden in serum is associated with significant and meaningful reductions in risk for a variety of cardiovascular endpoints, including myocardial infarction, ischaemic stroke, development of peripheral arterial disease and mortality. This review provides an overview on how to best position lipid-lowering drugs when attempting to normalize serum lipid profiles and reduce risk for cardiovascular disease. HMG-CoA reductase inhibitors (statins) are widely accepted to be the agents of choice for reducing serum levels of low-density lipoprotein cholesterol (LDL-C) in both the primary and secondary prevention settings. Ezetimibe and bile acid sequestrants are both effective agents for reducing LDL-C, either used alone or in combination with statins. The statins, fibric acid derivatives (fibrates) and niacin raise high-density lipoprotein cholesterol to different extents depending upon genetic and metabolic background. Fibrates, niacin and omega-3 fish oils are efficacious therapies for reducing serum triglycerides. Combinations of these drugs are frequently required for normalizing mixed forms of dyslipidaemia.

Apolipoprotein B100 secretion by cultured ARPE-19 cells is modulated by alteration of cholesterol levels

Cholesteryl ester rich apolipoprotein B100 (apoB100) lipoproteins accumulate in Bruch's membrane before the development of age-related macular degeneration. It is not known if these lipoproteins come from the circulation or local ocular tissue. Emerging, but incomplete evidence suggests that the retinal pigmented epithelium (RPE) can secrete lipoproteins. The purpose of this investigation was to determine (i) whether human RPE cells synthesize and secrete apoB100, and (ii) whether this secretion is driven by cellular cholesterol, and if so, (iii) whether statins inhibit this response. The established, human derived ARPE-19 cells challenged with 0-0.8 mM oleic acid accumulated cellular cholesterol, but not triglycerides. Oleic acid increased the amount of apoB100 protein recovered from the medium by both western blot analysis and (35) S-radiolabeled immunoprecipitation while negative stain electron microscopy showed lipoprotein-like particles. Of nine statins evaluated, lipophilic statins induced HMG-CoA reductase mRNA expression the most. The lipophilic Cerivastatin (5 μM) reduced cellular cholesterol by 39% and abrogated apoB100 secretion by 3-fold. In contrast, the hydrophilic statin Pravastatin had minimal effect on apoB100 secretion. These data suggest that ARPE-19 cells synthesize and secrete apoB100 lipoproteins, that this secretion is driven by cellular cholesterol, and that statins can inhibit apoB100 secretion by reducing cellular cholesterol.

The effect of adding plant sterols or stanols to statin therapy in hypercholesterolemic patients: systematic review and meta-analysis

OBJECTIVE

To characterize the effect of plant sterols/stanols on serum lipids in hypercholesterolemic patients on concurrent statin therapy, we conducted a meta-analysis of randomized controlled trials.

METHODS

A systematic literature search of MEDLINE, EMBASE, Cochrane CENTRAL, and the Natural Medicines Comprehensive Database was conducted from the earliest possible date through May 2008. Trials were included in the analysis if they were randomized controlled trials evaluating the use of plant sterols/stanols in combination with statins in hypercholesterolemic patients that reported efficacy data on total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, or triglycerides. The weighted mean difference (WMD) of the change from baseline (in mg/dL) with 95% confidence interval (CI) was calculated as the difference between the mean in the plant sterol/stanol groups and the control groups, using a random-effects model.

RESULTS

Eight studies (n = 306 patients) met the inclusion criteria. Upon meta-analysis, the use of plant sterols/stanols in combination with statin therapy significantly lowered total cholesterol (WMD, -14.01 mg/dL [95% CI, -18.66 to -9.37], p < 0.0001) and LDL cholesterol (WMD, -13.26 mg/dL [95% CI, -17.34 to -9.18], p < 0.0001) but not HDL cholesterol or triglycerides.

CONCLUSIONS

Based upon the current literature, we can only say that plant sterols/stanols, when administered in addition to statins, favorably affect total and LDL cholesterol with 95% confidence. Randomized trials examining the impact of plant sterols/stanols in combinatation with statins on patient morbidity and mortality are needed.

Dyslipidaemia in the metabolic syndrome and type 2 diabetes: pathogenesis, priorities, pharmacotherapies

IMPORTANCE OF THE FIELD

Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is usually characterized by high plasma concentrations of triglyceride-rich and apolipoprotein B (apoB)-containing lipoproteins, with depressed concentrations of high-density lipoprotein (HDL). Drug interventions are essential for normalizing metabolic dyslipidaemia.

AREAS COVERED IN THIS REVIEW

This review discusses the mechanisms and treatment for dyslipidaemia in the metabolic syndrome and type 2 diabetes.

WHAT THE READER WILL GAIN

A comprehensive understanding of the pathophysiology and pharmacotherapy of dyslipidaemia in the metabolic syndrome and diabetes.

TAKE HOME MESSAGE

Dysregulation of lipoprotein metabolism may be due to a combination of overproduction of triglyceride-rich lipoproteins, decreased catabolism of apoB-containing particles, and increased catabolism of HDL particles. These abnormalities may be consequent on a global metabolic effect of insulin resistance and an excess of both visceral and hepatic fat. Lifestyle modifications may favourably alter lipoprotein transport in the metabolic syndrome. Patients with dyslipidaemia and established cardiovascular disease should receive a statin as first-line therapy. Combination with other lipid-regulating agents, such as ezetimibe, fibrates, niacins and fish oils may optimize the benefit of statin on atherogenic dyslipidaemia.

Fibrate therapy in the management of dyslipidemias, alone and in combination with statins: role of delayed-release fenofibric acid

IMPORTANCE OF THE FIELD

Optimization of lipid management is a crucial aspect in the treatment of cardiovascular disease. Currently, HMG-CO reductase inhibitors (statins) are a mainstay of therapy. While this class of drugs has proven efficacy at lowering low-density lipoprotein cholesterol (LDL-C), their effects on other important lipid parameters, such as high-density lipoprotein cholesterol (HDL-C) and triglycerides, are less robust.

AREAS COVERED IN THIS REVIEW

The current paper will address the significance of these secondary targets and review currently available therapies, including a new formulation of delayed-release fenofibric acid. A comprehensive MEDLINE search (1966 to September 2009) was performed.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive review of the importance of secondary cholesterol targets, as well as the effectiveness of currently available therapies to address non-LDL-C. The role of the newly released fenofibric acid will also be addressed, as well as its potential use in combination therapy with a statin.

TAKE HOME MESSAGE

Adequate treatment of lipid parameters beyond LDL-C is an essential component in the treatment of dyslipidemia. The fibrate class of drugs has proven efficacy in improving secondary targets; however, concerns regarding severe myopathy and rhabdomyolysis have limited their combination with statins. Recently, a new fibrate derivative, fenofibric acid, has become available. Studies to date reflect a positive safety and tolerability profile when combined with statins. This may offer a new tool to address the important secondary cholesterol targets that are becoming increasingly recognized as important contributors to cardiovascular outcomes.

Impact of lipid lowering therapy on liver function

A cardiovascularis megbetegedések hazánkban is vezetik a morbiditási és mortalitási statisztikákat. Ezen betegségek kialakulásában jelentős szerepet játszik a hyperlipidaemia. A korábbi nagy prospektív multicentrikus tanulmányok azt igazolták, hogy a hatékony lipidcsökkentő kezelés jelentős mértékű cardiovascularis halálozás-összhalálozás csökkenést eredményez. Ez a hatás függ az LDL-C-csökkentés mértékétől, amely gyakran csak a nagy dózisban alkalmazott statinkészítményekkel éri el a kívánt szintet. A nagy dózisban alkalmazott statinok a betegek körülbelül 3%-ában hozhatnak létre májkárosító hatást. A szerzők jelen munkájukban röviden ismertetik a lipidcsökkentő gyógyszerek hatásait, azokat a mechanizmusokat, amelyek a szerek potenciális májkárosító hatásának hátterében állhatnak. Felhívják a figyelmet arra, hogy a korábbi gyakorlattól eltérően, emelkedett transzaminázszintek esetén, sőt, bizonyos májbetegségekben is biztonságosan alkalmazhatóak a lipidcsökkentő készítmények. Természetesen akkor, ha megfelelő dózisban vagy kombinációban alkalmazzuk a gyógyszereket, és figyelemmel vagyunk azon tényezőkre, amelyek fokozhatják a nem kívánt mellékhatásokat. Ezen szempontok betartása mellett magas cardiovascularis rizikójú, egyébként krónikus májbetegségben szenvedők számára is biztosíthatjuk a lipidcsökkentők nyújtotta kedvező hatásokat anélkül, hogy fokoznánk a máj károsodását.

Dyslipidemia treatment of patients with diabetes mellitus in a US managed care plan: a retrospective database analysis

Background

To evaluate real-world pharmacologic treatment of mixed dyslipidemia in patients with diabetes mellitus (DM).

Methods

All commercial health plan members in a large US managed care database with complete lipid panel results (HDL-C, LDL-C, TG) between 1/1/2006 and 12/31/2006 were identified (N = 529,236). DM patients (N = 53,679) with mixed dyslipidemia were defined as having any 2 suboptimal lipid parameters (N = 28,728). Lipid treatment status 6 months pre- and post-index date was determined using pharmacy claims for any lipid therapy.

Results

Post-index, 41.1% of DM patients with 2 abnormal lipid parameters and 45.1% with 3 abnormal lipid parameters did not receive lipid-modifying treatment. Post-index treatment rates were 57.4%, 63.6%, and 66.4% for patients with LDL-C, HDL-C, and TG in the most severe quartiles, respectively. Statin monotherapy was the primary lipid-modifying regimen prescribed (54.8% and 47.8% of patients with any 2 and all 3 lipids not at goal, respectively). Less than 30% of treated patients received combination therapy.

Conclusion

Over 40% of DM patients with mixed dyslipidemia received no lipid-modifying therapy during the follow-up period. Those who were treated were primarily prescribed statin monotherapy. This study suggests that DM patients are not being treated to ADA-suggested targets.