Statin-induced inhibition of the Rho-signaling pathway activates PPARalpha and induces HDL apoA-I

Mass spectrometry-based approaches to targeted quantitative proteomics in cardiovascular disease

Mass spectrometry-based proteomics methodology has become an important tool in elucidating some of the underlying mechanisms involved in cardiovascular disease. The present review provides details on selected important protein targets where highly selective and specific mass spectrometry-based approaches have led to important new findings and provided new mechanistic information. The role of six proteins involved in the etiology of cardiovascular disease (acetylated platelet cyclooxygenase-1, serum apolipoprotein A1, apolipoprotein C-III, serum C-reactive protein, serum high mobility group box-1 protein, insulin-like growth factor I) and their quantification has been discussed. There are an increasing number of examples where highly selective mass spectrometry-based quantification has provided new important data that could not be obtained with less labor intensive and cheaper immunoassay-based procedures. It is anticipated that these findings will lead to significant advances in a number of important issues related to the role of specific proteins in cardiovascular disease. The availability of a new generation of high-resolution high-sensitivity mass spectrometers will greatly facilitate these studies so that in the future it will be possible to analyze serum proteins of relevance to cardiovascular disease with levels of specificity and/or sensitivity that cannot be attained by immunoassay-based procedures.

Insulin-Mediated Downregulation of Apolipoprotein A-I Gene in Human Hepatoma Cell Line HepG2: The Role of Interaction Between FOXO1 and LXRβ Transcription Factors

Apolipoprotein A-I (ApoA-I) is a key component of high density lipoproteins which possess anti-atherosclerotic and anti-inflammatory properties. Insulin is a crucial mediator of the glucose and lipid metabolism that has been implicated in atherosclerotic and inflammatory processes. Important mediators of insulin signaling such as Liver X Receptors (LXRs) and Forkhead Box A2 (FOXA2) are known to regulate apoA-I expression in liver. Forkhead Box O1 (FOXO1) is a well-known target of insulin signaling and a key mediator of oxidative stress response. Low doses of insulin were shown to activate apoA-I expression in human hepatoma HepG2 cells. However, the detailed mechanisms for these processes are still unknown. We studied the possible involvement of FOXO1, FOXA2, LXRα, and LXRβ transcription factors in the insulin-mediated regulation of apoA-I expression. Treatment of HepG2 cells with high doses of insulin (48 h, 100 nM) suppresses apoA-I gene expression. siRNAs against FOXO1, FOXA2, LXRβ, or LXRα abrogated this effect. FOXO1 forms a complex with LXRβ and insulin treatment impairs FOXO1/LXRβ complex binding to hepatic enhancer and triggers its nuclear export. Insulin as well as LXR ligand TO901317 enhance the interaction between FOXA2, LXRα, and hepatic enhancer. These data suggest that high doses of insulin downregulate apoA-I gene expression in HepG2 cells through redistribution of FOXO1/LXRβ complex, FOXA2, and LXRα on hepatic enhancer of apoA-I gene. J. Cell. Biochem. 118: 382-396, 2017. © 2016 Wiley Periodicals, Inc.

Hepatic Fgf21 Expression Is Repressed after Simvastatin Treatment in Mice

Fibroblast growth factor 21 (Fgf21) is a hormone with emerging beneficial roles in glucose and lipid homeostasis. The interest in Fgf21 as a potential antidiabetic drug and the factors that regulate its production and secretion is growing. Statins are the most widely prescribed drug for the treatment of dyslipidemia. However, the function of statins is not limited to the lowering of cholesterol as they are associated with pleiotropic actions such as antioxidant, anti-inflammatory and cytoprotective effects. The recently described effect of statins on mitochondrial function and the induction of Fgf21 by mitochondrial stress prompted us to investigate the effect of statin treatment on Fgf21 expression in the liver. To this end, C57BL6J male mice and primary mouse hepatocytes were treated with simvastatin, and Fgf21 expression was subsequently assessed by immunoblotting and quantitative real-time PCR. Hepatic Fgf21 protein and mRNA and circulating levels of FGF21significantly decreased in mice that had received simvastatin in their food (0.1% w/w) for 1 week. This effect was also observed with simvastatin doses as low as 0.01% w/w for 1 week or following 2 intraperitoneal injections within a single day. The reduction in Fgf21 mRNA levels was further verified in primary mouse hepatocytes, indicating that the effect of simvastatin is cell autonomous. In conclusion, simvastatin treatment reduced the circulating and hepatic Fgf21 levels and this effect warrants further investigation with reference to its role in metabolism.

Pathophysiological effects of RhoA and Rho-associated kinase on cardiovascular system

In past decades, growing evidence from basic and clinical researches reveal that small guanosine triphosphate binding protein ras homolog gene family, member A (RhoA) and its main effector Rho-associated kinase (ROCK) play central and complex roles in cardiovascular systems, and increasing RhoA and ROCK activity is associated with a broad range of cardiovascular diseases such as congestive heart failure, atherosclerosis, and hypertension. Favorable outcomes have been observed with ROCK inhibitors treatment. In this review, we briefly summarize the pathophysiological roles of RhoA/ROCK signaling pathway on cardiovascular system, displaying the potential benefits in the cardiovascular system with controlling RhoA/ROCK signaling pathway.

Nutritional and Hormonal Regulation of Citrate and Carnitine/Acylcarnitine Transporters: Two Mitochondrial Carriers Involved in Fatty Acid Metabolism

The transport of solutes across the inner mitochondrial membrane is catalyzed by a family of nuclear-encoded membrane-embedded proteins called mitochondrial carriers (MCs). The citrate carrier (CiC) and the carnitine/acylcarnitine transporter (CACT) are two members of the MCs family involved in fatty acid metabolism. By conveying acetyl-coenzyme A, in the form of citrate, from the mitochondria to the cytosol, CiC contributes to fatty acid and cholesterol synthesis; CACT allows fatty acid oxidation, transporting cytosolic fatty acids, in the form of acylcarnitines, into the mitochondrial matrix. Fatty acid synthesis and oxidation are inversely regulated so that when fatty acid synthesis is activated, the catabolism of fatty acids is turned-off. Malonyl-CoA, produced by acetyl-coenzyme A carboxylase, a key enzyme of cytosolic fatty acid synthesis, represents a regulator of both metabolic pathways. CiC and CACT activity and expression are regulated by different nutritional and hormonal conditions. Defects in the corresponding genes have been directly linked to various human diseases. This review will assess the current understanding of CiC and CACT regulation; underlining their roles in physio-pathological conditions. Emphasis will be placed on the molecular basis of the regulation of CiC and CACT associated with fatty acid metabolism.

Effect of Leptin Administration on Circulating Apolipoprotein CIII levels in Patients With Lipodystrophy

CONTEXT

Apolipoprotein CIII (apoCIII), an inhibitor of lipoprotein lipase, plays an important role in triglyceride metabolism. However, the role of apoCIII in hypertriglyceridemia in lipodystrophy and the effects of leptin replacement on apoCIII levels are unknown.

OBJECTIVE

The objective of the study was to test the hypotheses that apoCIII is elevated in hypertriglyceridemic patients with lipodystrophy and that leptin replacement in these patients lowers circulating apoCIII.

DESIGN, SETTING, STUDY PARTICIPANTS, INTERVENTION, AND OUTCOME MEASURES

Using a post hoc cross-sectional case-control design, we compared serum apoCIII levels from patients with lipodystrophy not associated with HIV (n = 60) and age-, gender-, race-, and ethnicity-matched controls (n = 54) participating in ongoing studies at the National Institutes of Health. In a prospective, open-label, ongoing study, we studied the effects of 6–12 months of leptin replacement on apoCIII in lipodystrophy patients as an exploratory outcome.

RESULTS

ApoCIII was higher in lipodystrophy patients (geometric mean [25th and 75th percentiles]) (23.9 mg/dL [14.6, 40.3]) compared with controls (14.9 mg/dL [12.3, 17.7]) (P < .0001). ApoCIII and triglyceride levels were positively correlated in patients with lipodystrophy (R = 0.72, P < .0001) and healthy controls (R = 0.6, P < .0001). Leptin replacement (6–12 mo) did not significantly alter apoCIII (before leptin: 23.4 mg/dL [14.5, 40.1]; after leptin: 21.4 mg/dL [16.7, 28.3]; P = .34).

CONCLUSIONS

Leptin replacement in lipodystrophy did not alter serum apoCIII levels. Elevated apoCIII may play a role in the hypertriglyceridemia of lipodystrophy independent of leptin deficiency and replacement.

Rosuvastatin Alters the Proteome of High Density Lipoproteins: Generation of alpha-1-antitrypsin Enriched Particles with Anti-inflammatory Properties

Statins lower plasma cholesterol by as much as 50%, thus reducing future cardiovascular events. However, the physiological effects of statins are diverse and not all are related to low density lipoprotein cholesterol (LDL-C) lowering. We performed a small clinical pilot study to assess the impact of statins on lipoprotein-associated proteins in healthy individuals (n = 10) with normal LDL-C (<130 mg/dL), who were treated with rosuvastatin (20 mg/day) for 28 days. Proteomic analysis of size-exclusion chromatography isolated LDL, large high density lipoprotein (HDL-L), and small HDL (HDL-S) fractions and spectral counting was used to compare relative protein detection before and after statin therapy. Significant protein changes were found in each lipoprotein pool and included both increases and decreases in several proteins involved in lipoprotein metabolism, complement regulation and acute phase response. The most dramatic effect of the rosuvastatin treatment was an increase in α-1-antirypsin (A1AT) spectral counts associated with HDL-L particles. Quantitative measurement by ELISA confirmed an average 5.7-fold increase in HDL-L associated A1AT. Molecular modeling predictions indicated that the hydrophobic reactive center loop of A1AT, the functional domain responsible for its protease inhibitor activity, is likely involved in lipid binding and association with HDL was found to protect A1AT against oxidative inactivation. Cell culture experiments, using J774 macrophages, demonstrated that the association of A1AT with HDL enhances its antiprotease activity, preventing elastase induced production of tumor necrosis factor α. In conclusion, we show that statins can significantly alter the protein composition of both LDL and HDL and our studies reveal a novel functional relationship between A1AT and HDL. The up-regulation of A1AT on HDL enhances its anti-inflammatory functionality, which may contribute to the non-lipid lowering beneficial effects of statins.

Statins Increase Plasminogen Activator Inhibitor Type 1 Gene Transcription through a Pregnane X Receptor Regulated Element

Plasminogen activator inhibitor type 1 (PAI-1) is a multifunctional protein that has important roles in inflammation and wound healing. Its aberrant regulation may contribute to many disease processes such as heart disease. The PAI-1 promoter is responsive to multiple inputs including cytokines, growth factors, steroids and oxidative stress. The statin drugs, atorvastatin, mevastatin and rosuvastatin, increased basal and stimulated expression of the PAI-1 promoter 3-fold. A statin-responsive, nuclear hormone response element was previously identified in the PAI-1 promoter, but it was incompletely characterized. We characterized this direct repeat (DR) of AGGTCA with a 3-nucleotide spacer at -269/-255 using deletion and directed mutagenesis. Deletion or mutation of this element increased basal transcription from the promoter suggesting that it repressed PAI-1 transcription in the unliganded state. The half-site spacing and the ligand specificity suggested that this might be a pregnane X receptor (PXR) responsive element. Computational molecular docking showed that atorvastatin, mevastatin and rosuvastatin were structurally compatible with the PXR ligand-binding pocket in its agonist conformation. Experiments with Gal4 DNA binding domain fusion proteins showed that Gal4-PXR was activated by statins while other DR + 3 binding nuclear receptor fusions were not. Overexpression of PXR further enhanced PAI-1 transcription in response to statins. Finally, ChIP experiments using Halo-tagged PXR and RXR demonstrated that both components of the PXR-RXR heterodimer bound to this region of the PAI-1 promoter.

Effect of telmisartan on the therapeutic efficacy of pitavastatin in high-fat diet induced dyslipidemic guinea pigs

Angiotensin II-receptor blockers (ARBs), similar to HMG-CoA reductase inhibitors (statins), could improve lipid metabolism abnormalities. There might be some cross-talking pathways between statins and ARBs to produce additive beneficial effects on lipid metabolism in dyslipidemia. However, few studies investigate the effects of ARBs on the therapeutic efficacy of statins in dyslipidemia. The present study was designed to systematically evaluate the effects of telmisartan on the therapeutic efficacy of pitavastatin on lowering lipid level and reducing fat deposition by employing a dyslipidemia model, guinea pigs. 48 Male guinea pigs fed with high-fat diet were randomly grouped and treated with vehicle, telmisartan, pitavastatin or telmisartan/pitavastatin combinations. After treatment for eight weeks, telmisartan could significantly enhance the therapeutic efficacy of pitavastatin by extremely reducing body weight gain, weight of adipose tissue and adipocyte size. However, telmisartan/pitavastatin combinations could not further improve lipid levels on the basis of pitavastain, though single telmisartan markedly decreased triglyceride (TG) and slightly increased high density lipoprotein cholesterol (HDL-C). Moreover, telmisartan/pitavastatin combinations significantly upregulated the gene expression level of peroxisome proliferator-activated receptor (PPAR)-δ, but no effects on the expression of PPAR-α/γ, leptin and adiponectin compared to monotherapy. Taken together, our studies provided new evidences that telmisartan has an additive beneficial influence on decreasing fat deposition and weight gain through PPAR-δ pathway but cannot enhance the therapeutic efficacy of pitavastatin on lowering lipid levels. The combinational administration of telmisartan and pitavastatin could be a potential therapeutic strategy for dyslipidemia related obesity and worthy of further investigation in obese animal models.

Endothelial protective genes induced by statin are mimicked by ERK5 activation as triggered by a drug combination of FTI-277 and GGTI-298

BACKGROUND

Statins are potent inhibitors of cholesterol biosynthesis and are clinically beneficial in preventing cardiovascular diseases, however, the therapeutic utility of these drugs is limited by myotoxicity. Here, we explored the mechanism of statin-mediated activation of ERK5 in the human endothelium with the goal of identifying compounds that confer endothelial protection but are nontoxic to muscle.

METHODS

An ERK5-one hybrid luciferase reporter transfected into COS-7 cells with pharmacological and molecular manipulations dissected the signaling pathway leading to statin activation of ERK5. qRT-PCR of HUVEC cells documented the transcriptional activation of endothelial-protective genes. Lastly, morphological and cellular ATP analysis, and induction of atrogin-1 in C2C12 myotubes were used to assess statin-induced myopathy.

RESULTS

Statin activation of ERK5 is dependent on the cellular reduction of GGPPs. Furthermore, we found that the combination of FTI-277 (inhibitor of farnesyl transferase) and GGTI-298 (inhibitor of geranylgeranyl transferase I) mimicked the statin-mediated activation of ERK5. FTI-277 and GGTI-298 together recapitulated the beneficial effects of statins by transcriptionally upregulating anti-inflammatory mediators such as eNOS, THBD, and KLF2. Finally, C2C12 skeletal myotubes treated with both FTI-277 and GGTI-298 evoked less morphological and cellular changes recognized as biomarkers of statin-associated myopathy.

CONCLUSIONS

Statin-induced endothelial protection and myopathy are mediated by distinct metabolic intermediates and co-inhibition of farnesyl transferase and geranylgeranyl transferase I confer endothelial protection without myopathy.

GENERAL SIGNIFICANCE

The combinatorial FTI-277 and GGTI-298 drug regimen provides a promising alternative avenue for endothelial protection without myopathy.

Relation between paradoxical decrease in high-density lipoprotein cholesterol levels after statin therapy and adverse cardiovascular events in patients with acute myocardial infarction

Statin therapy moderately increases high-density lipoprotein cholesterol (HDL-C) levels. Contrary to this expectation, a paradoxical decrease in HDL-C levels after statin therapy is seen in some patients. We evaluated 724 patients who newly started treatment with statins after acute myocardial infarction (AMI). These patients were divided into 2 groups according to change in HDL-C levels between baseline and 6 to 9 months after initial AMI (ΔHDL). In total, 620 patients had increased HDL-C levels and 104 patients had decreased HDL-C levels. Both groups achieved follow-up low-density lipoprotein cholesterol levels <100 mg/dl. Adverse cardiovascular events (a composite of all-cause death, myocardial infarction, and stroke) have more frequently occurred in the decreased HDL group compared with the increased HDL group (15.4% vs 7.1%, p = 0.01). Multivariate analysis showed that decreased HDL, onset to balloon time, and multivessel disease were the independent predictors of adverse cardiovascular events (hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.08 to 3.52; HR 1.05, 95% CI 1.01 to 1.09; and HR 2.08, 95% CI 1.22 to 3.56, respectively). In conclusion, a paradoxical decrease in serum HDL-C levels after statin therapy might be an independent predictor of long-term adverse cardiovascular events in patients with AMI.

Fibrates protect against vascular endothelial dysfunction induced by paclitaxel and carboplatin chemotherapy for cancer patients: a pilot study

BACKGROUND

Although we previously demonstrated that paclitaxel and carboplatin chemotherapy (TCchem) is associated with vascular toxicities, the underlying mechanisms remain unclear. Cisplatin is known to inhibit PPARα following microvascular damage to the kidneys. The primary aim of this study was to evaluate whether TCchem induces vascular endothelial dysfunction via systemic PPARα deficiency. In addition, human umbilical vein endothelial cells (HUVECs) were used to elucidate the mechanisms responsible for TCchem-induced vascular toxicities.

METHODS

This study enrolled 45 gynecological cancer patients with normal lipid profiles who underwent surgical treatment followed by TCchem. The elevated triglyceride (TG) group included patients (n = 19) who exhibited hypertriglyceridemia during TCchem, and the stable TG group (n = 15) included patients with a normal TG level. Eleven patients exhibiting hypertriglyceridemia during TCchem were administered bezafibrate (fibrate group). Endothelial dysfunction was evaluated based on flow-mediated dilation (FMD) values and serum pentraxin-3 levels measured before TCchem and immediately after the final TCchem. HUVECs were used to elucidate the biological mechanisms underlying the endothelial dysfunction induced by TCchem.

RESULTS

The administration of TCchem induced hypertriglyceridemia in 66 percent of the participants, and bezafibrate reduced the serum TG levels. Meanwhile, the decrease in flow-mediated dilatation (%FMD) induced by TCchem improved following treatment with bezafibrate. The serum pentraxin-3 level increased rapidly after TCchem and decreased following bezafibrate treatment. An in vitro examination demonstrated TCchem attenuated nitric oxide production and PPARα activity in HUVECs, which was partially improved by treatment with bezafibrate.

CONCLUSION

Bezafibrate prevents endothelial dysfunction induced by TCchem via TG-dependent and TG-independent mechanisms.

Associations of hydroxychloroquine use with lipid profiles in rheumatoid arthritis: pharmacologic implications

OBJECTIVE

To evaluate the association of hydroxychloroquine (HCQ) use with lipid profiles in a Veterans Affairs Rheumatoid Arthritis (VARA) cohort.

METHODS

Lipid profiles in HCQ users were compared with HCQ nonusers, adjusting for potential confounders (age, sex, race, disease activity, prednisone, disease-modifying antirheumatic drugs, diabetes mellitus, and statin use). Applying current National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) guidelines for reduction of cardiovascular disease (CVD) events risk, the frequency of target lipid profiles with HCQ status was evaluated. Varied periods of HCQ exposure were compared to ascertain pharmacologic associations with lipid values. CVDs were compared between HCQ users and nonusers.

RESULTS

In an elderly, predominantly male VARA cohort, 1,011 patients had lipid profiles; 787 patients (77.8%) were white. Statin use was recorded in 11.6% of patients, diabetes mellitus in 33.5%, and CVD in 31.2%. HCQ users (n = 150) were older, had longer rheumatoid arthritis (RA) disease duration, and had lower disease activity. Optimum lipid profiles, including total cholesterol:high-density lipoprotein (HDL) and HDL:low-density lipoprotein ratios (P ≤ 0.001), were more frequent in HCQ users, with the exception of HDL (P = 0.165), and persisted in multivariate analyses. Similarly, more HCQ users had NCEP-ATP III target levels. Varied periods of HCQ exposure suggested lipid changes to occur early, but lost within a year of drug discontinuation. HCQ users had less prevalent CVD.

CONCLUSION

In RA patients, HCQ use of at least 3 months' duration was associated with better lipid profiles irrespective of disease activity or statin use. Given the increased CVD risks in RA and the relative low cost and toxicity of HCQ, continued use, regardless of treatment regimen, should be considered.

Should low high-density lipoprotein cholesterol (HDL-C) be treated?

The first observations linking a low serum level of HDL-C to increased risk for cardiovascular disease were made over 50 years ago. High serum levels of HDL-C appear to protect against the development of atherosclerotic disease, while low serum levels of this lipoprotein are among the most important predictors of atherosclerotic disease in both men and women and people of all racial and ethnic groups throughout the world. It has long been assumed that therapeutic interventions targeted at raising HDL-C levels would lower risk for such cardiovascular events as myocardial infarction, ischemic stroke, and death. Even after five decades of intensive investigation, evidence to support this assumption has been fleeting. A number of post hoc analyses of randomized controlled trials and meta-analyses suggest that HDL-C raising, particularly when coupled with aggressive LDL-C reduction, impacts risk for cardiovascular events and rates of progression of atherosclerotic disease. Unfortunately, four recent prospective trials performed with the intent of testing the "HDL hypothesis" (ILLUMINATE, dal-OUTCOMES, AIM-HIGH, and HPS2-THRIVE) failed to meet their primary composite endpoints. These results have lead many clinicians and investigators to question the validity of the assumption that HDL-C raising reduces risk for cardiovascular events. Additional trials with other drugs are underway. In the meantime, HDL-C cannot be considered a target of therapy. Given the complexity of the HDL proteome and lipidome, there is biological plausibility for how HDL particles might exert atheroprotection. We explore the evidence supporting the inverse relationship between HDL-C and cardiovascular disease risk, documented mechanisms by which HDL particles may exert atheroprotection, and the findings either supporting or negating specific therapeutic interventions in patients afflicted with low HDL-C.

Atorvastatin improves plaque stability in ApoE-knockout mice by regulating chemokines and chemokine receptors

It is well documented that statins protect atherosclerotic patients from inflammatory changes and plaque instability in coronary arteries. However, the underlying mechanisms are not fully understood. Using a previously established mouse model for vulnerable atherosclerotic plaque, we investigated the effect of atorvastatin (10 mg/kg/day) on plaque morphology. Atorvastatin did not lower plasma total cholesterol levels or affect plaque progression at this dosage; however, vulnerable plaque numbers were significantly reduced in the atorvastatin-treated group compared to control. Detailed examinations revealed that atorvastatin significantly decreased macrophage infiltration and subendothelial lipid deposition, reduced intimal collagen content, and elevated collagenase activity and expression of matrix metalloproteinases (MMPs). Because vascular inflammation is largely driven by changes in monocyte/macrophage numbers in the vessel wall, we speculated that the anti-inflammatory effect of atorvastatin may partially result from decreased monocyte recruitment to the endothelium. Further experiments showed that atorvastatin downregulated expression of the chemokines monocyte chemoattractant protein (MCP)-1, chemokine (C-X3-C motif) ligand 1 (CX3CL1) and their receptors CCR2 and, CX3CR1, which are mainly responsible for monocyte recruitment. In addition, levels of the plasma inflammatory markers C-reactive protein (CRP) and tumor necrosis factor (TNF)-α were also significantly decrease in atorvastatin-treated mice. Collectively, our results demonstrate that atorvastatin can improve plaque stability in mice independent of plasma cholesterol levels. Given the profound inhibition of macrophage infiltration into atherosclerotic plaques, we propose that statins may partly exert protective effects by modulating levels of chemokines and their receptors. These findings elucidate yet another atheroprotective mechanism of statins.

The peroxisome proliferator-activated receptor alpha agonist fenofibrate has no effect on insulin sensitivity compared to atorvastatin in type 2 diabetes mellitus; a randomised, double-blind controlled trial

AIMS

Assess insulin sensitivity after treatment with a selective PPAR-alpha agonist compared to an HMG CoA reductase inhibitor in human subjects with type 2 diabetes mellitus.

METHODS

Thirteen subjects with Type 2 diabetes mellitus were studied in a double-blind crossover design with 4-week placebo run-in and washout and 12-week treatment periods, randomised to micronised fenofibrate 267 mg or atorvastatin 10mg daily followed by the alternate drug in the second period. Insulin resistance was measured using the isoglycaemic hyperinsulinaemic clamp method with isotope dilution.

RESULTS

Weight, physical activity and other medications did not change. Total cholesterol (mean +/- standard error) was 4.60+/-0.21 versus 3.9+/-0.22 mmol/L after fenofibrate and atorvastatin respectively, p<0.05. LDL was 2.70+/-0.19 versus 1.95+/-0.23 mmol/L, p<0.05 and triglyceride 1.64+/-0.23 versus 1.84+/-0.26 mmol/L, p<0.05. Insulin-stimulated whole-body glucose disposal (35.4+/-3.1 versus 33.2+/-3.0 μmol/kg/min) and nadir endogenous glucose production (6.2+/-1.4 versus 7.0+/-1.1 μmol/kg/min) revealed no significant differences in effects of the treatments.

CONCLUSIONS

In human subjects with Type 2 diabetes mellitus there were characteristic differences in lipid profile changes but no difference in insulin sensitivity after treatment with micronised fenofibrate compared to atorvastatin. This study finds no evidence of increased insulin sensitivity using this selective PPAR-alpha agonist over a commonly used statin at these doses.

Acute exacerbation of chronic obstructive pulmonary disease: cardiovascular links

Chronic obstructive pulmonary disease (COPD) is a chronic, progressive lung disease resulting from exposure to cigarette smoke, noxious gases, particulate matter, and air pollutants. COPD is exacerbated by acute inflammatory insults such as lung infections (viral and bacterial) and air pollutants which further accelerate the steady decline in lung function. The chronic inflammatory process in the lung contributes to the extrapulmonary manifestations of COPD which are predominantly cardiovascular in nature. Here we review the significant burden of cardiovascular disease in COPD and discuss the clinical and pathological links between acute exacerbations of COPD and cardiovascular disease.

Rosuvastatin: a highly potent statin for the prevention and management of coronary artery disease

Since the identification of a fungal metabolite that inhibits HMG-CoA reductase in 1976, statins have emerged rapidly as the global leader in pharmacotherapeutics designed to lower low-density lipoprotein cholesterol (LDL-C). In conjunction, practice guidelines have recommended increasingly aggressive measures to improve coronary heart disease (CHD) outcomes by lowering LDL-C. By virtue of unique chemical characteristics, enhanced binding thermodynamics and limited cytochrome P450 3A4 metabolism, rosuvastatin calcium has a safety profile in line with currently marketed statins, but a different efficacy profile. Mirroring this chemical profile, the GALAXY program represents a comprehensive evaluation of the efficacy, safety and cost-effectiveness of rosuvastatin in individuals representing various clinical diagnoses, pathophysiological states and ethnicities. Also results from the Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) study could provide further evidence for the use of rosuvastatin in individuals with traditional and emerging CHD risk factors, such as an elevated high sensitivity C-reactive protein level. This review will provide a comprehensive evaluation of the chemistry, clinical efficacy, safety and tolerability of rosuvastatin, and discuss the future role in the management of CHD and atherosclerosis.

Atorvastatin and hormone therapy influence expression of ABCA1, APOA1 and SCARB1 in mononuclear cells from hypercholesterolemic postmenopausal women

BACKGROUND

Reverse cholesterol transport (RCT) has been inversely related to atherosclerosis and cardiovascular risk. The influence of menopause in the RCT process is poorly understood and the effects of cholesterol-lowering interventions, including statins and hormone therapy (HT), on genes controlling the RCT in postmenopausal women are also unknown.

METHODS

The effects on serum lipids and expression profile of genes involved in RCT - APOA1, ABCA1, ABCG1, SCARB1 and LXRA - were evaluated by TaqMan(®) quantitative PCR in peripheral blood mononuclear cells (PBMC) from 87 postmenopausal hypercholesterolemic women treated with atorvastatin (AT, n=17), estrogen or estrogen plus progestin (HT, n=34) and estrogen or estrogen plus progestin associated with atorvastatin (HT+AT, n=36).

RESULTS

Atorvastatin and HT treatments reduced the mRNA levels of APOA1 and SCARB1, respectively, whereas ABCA1 expression was reduced after all treatments. Although the expression of LXRA, an important transcription factor controlling the expression of genes involved in RCT, was not modified after any treatment, it was correlated with ABCA1, APOA1 and SCARB1 RNAm values before and after treatments, however no correlation with ABCG1 was observed. In a linear regression analysis, HT was related to an increase in apoAI levels after treatment when compared to atorvastatin and, moreover, higher SCARB1 and ABCA1 basal expression were also associated with decreased apoAI levels after treatments.

CONCLUSION

ABCA1 mRNA levels are decreased by atorvastatin and HT, however these treatments have a differential effect on APOA1 and SCARB1 expression in PBMC from postmenopausal women. Basal ABCA1 and SCARB1 expression profile could be helpful markers in predicting the effect of atorvastatin and HT on RCT, according to the changes in apoAI levels in this sample population.

Small G Proteins in the Cardiovascular System: Physiological and Pathological Aspects

Small G proteins exist in eukaryotes from yeast to human and constitute the Ras superfamily comprising more than 100 members. This superfamily is structurally classified into five families: the Ras, Rho, Rab, Arf, and Ran families that control a wide variety of cell and biological functions through highly coordinated regulation processes. Increasing evidence has accumulated to identify small G proteins and their regulators as key players of the cardiovascular physiology that control a large panel of cardiac (heart rhythm, contraction, hypertrophy) and vascular functions (angiogenesis, vascular permeability, vasoconstriction). Indeed, basal Ras protein activity is required for homeostatic functions in physiological conditions, but sustained overactivation of Ras proteins or spatiotemporal dysregulation of Ras signaling pathways has pathological consequences in the cardiovascular system. The primary object of this review is to provide a comprehensive overview of the current progress in our understanding of the role of small G proteins and their regulators in cardiovascular physiology and pathologies.

Statins and lipid metabolism: an update

PURPOSE OF REVIEW

The reduction in cardiovascular disease risk by statins is well established. This risk reduction has mostly been attributed to decreases in plasma LDL cholesterol and other pleiotropic effects of statins. Emerging evidence indicates that statins exert multiple effects on lipoprotein metabolism, including chylomicrons and HDLs.

RECENT FINDINGS

Kinetic and in-vitro studies have documented that the effects of statins on the metabolism of different lipoproteins are for the most part the direct consequence of cholesterol biosynthesis inhibition and the subsequent change in transcription factors and cell signaling, regulating different aspects of lipoprotein metabolism. Differences in pharmacokinetics and pharmacodynamics among statins lead to diverse biological outcomes.

SUMMARY

The current review summarizes recent experimental evidence highlighting the different effects of statins on cellular pathways regulating gene expression. Understanding the basic mechanisms by which different statins regulate lipoprotein metabolism will lead to improved strategies for the prevention and treatment of specific lipoprotein disorders.

Transcriptional Regulation of the Mitochondrial Citrate and Carnitine/Acylcarnitine Transporters: Two Genes Involved in Fatty Acid Biosynthesis and β-oxidation

Transcriptional regulation of genes involved in fatty acid metabolism is considered the major long-term regulatory mechanism controlling lipid homeostasis. By means of this mechanism, transcription factors, nutrients, hormones and epigenetics control not only fatty acid metabolism, but also many metabolic pathways and cellular functions at the molecular level. The regulation of the expression of many genes at the level of their transcription has already been analyzed. This review focuses on the transcriptional control of two genes involved in fatty acid biosynthesis and oxidation: the citrate carrier (CIC) and the carnitine/ acylcarnitine/carrier (CAC), which are members of the mitochondrial carrier gene family, SLC25. The contribution of tissue-specific and less tissue-specific transcription factors in activating or repressing CIC and CAC gene expression is discussed. The interaction with drugs of some transcription factors, such as PPAR and FOXA1, and how this interaction can be an attractive therapeutic approach, has also been evaluated. Moreover, the mechanism by which the expression of the CIC and CAC genes is modulated by coordinated responses to hormonal and nutritional changes and to epigenetics is highlighted.

Targeting GGTase-I activates RHOA, increases macrophage reverse cholesterol transport, and reduces atherosclerosis in mice

BACKGROUND

Statins have antiinflammatory and antiatherogenic effects that have been attributed to inhibition of RHO protein geranylgeranylation in inflammatory cells. The activity of protein geranylgeranyltransferase type I (GGTase-I) is widely believed to promote membrane association and activation of RHO family proteins. However, we recently showed that knockout of GGTase-I in macrophages activates RHO proteins and proinflammatory signaling pathways, leading to increased cytokine production and rheumatoid arthritis. In this study, we asked whether the increased inflammatory signaling of GGTase-I-deficient macrophages would influence the development of atherosclerosis in low-density lipoprotein receptor-deficient mice.

METHODS AND RESULTS

Aortic lesions in mice lacking GGTase-I in macrophages (Pggt1b▵/▵) contained significantly more T lymphocytes than the lesions in controls. Surprisingly, however, mean atherosclerotic lesion area in Pggt1b▵/▵ mice was reduced by ≈60%. GGTase-I deficiency reduced the accumulation of cholesterol esters and phospholipids in macrophages incubated with minimally modified and acetylated low-density lipoprotein. Analyses of GGTase-I-deficient macrophages revealed upregulation of the cyclooxygenase 2-peroxisome proliferator-activated-γ pathway and increased scavenger receptor class B type I- and CD36-mediated basal and high-density lipoprotein-stimulated cholesterol efflux. Lentivirus-mediated knockdown of RHOA, but not RAC1 or CDC42, normalized cholesterol efflux. The increased cholesterol efflux in cultured cells was accompanied by high levels of macrophage reverse cholesterol transport and slightly reduced plasma lipid levels in vivo.

CONCLUSIONS

Targeting GGTase-I activates RHOA and leads to increased macrophage reverse cholesterol transport and reduced atherosclerosis development despite a significant increase in inflammation.

Cocoa flavanol metabolites activate HNF-3β, Sp1, and NFY-mediated transcription of apolipoprotein AI in human cells

SCOPE

To identify the mechanisms by which cocoa induces HDL levels and since apolipoprotein AI (ApoAI) is the major protein in HDLs, we analyzed, upon incubation with cocoa metabolites, ApoAI mRNA levels, its transcriptional regulation, and the levels of the transcription factors involved in this process.

METHODS AND RESULTS

Epicatechin and cocoa metabolites caused an increase in ApoAI expression in HepG2 cells. Electrophoretic mobility shift assays revealed the involvement of Sites A and B of the ApoAI promoter in the induction of ApoAI mRNA upon incubation with cocoa metabolites. Using supershift assays, we demonstrated the binding of HNF-3β, HNF-4, ER-α, and RXR-α to Site A and the binding of HNF-3β, NFY, and Sp1 to Site B. Luciferase assays performed with a construct containing Site B confirmed its role in the upregulation of ApoAI by cocoa metabolites. Incubation with 3-methyl-epicatechin led to an increase in HNF-3β mRNA, HNF-3β, ER-α, Sp1, and NFY protein levels and the activation of ApoAI transcription mediated by NFY, Sp1, and ER-α.

CONCLUSION

The activation of ApoAI transcription through Site B by cocoa flavanol metabolites is mainly mediated by an increase in HNF-3β, with a significant contribution of Sp1 and NFY, as a mechanism for the protective role of these compounds in cardiovascular diseases.

Statin treatment improves plasma lipid levels but not HDL subclass distribution in patients undergoing percutaneous coronary intervention

Despite the established efficacy of statin therapy, the risk of cardiovascular events remains high in many patients. We examined high-density lipoprotein (HDL) subclass distribution profiles among statin-treated coronary heart disease (CHD) patients undergoing percutaneous coronary intervention (PCI). Plasma HDL subclasses were measured in 85 patients with established CHD and quantified by two-dimensional gel electrophoresis and immunoblotting. In CHD patients with statin treatment, the mean value of total cholesterol (TC) reached the desirable level and the triacylglycerol level (TAG) was borderline high. Moreover, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), apolipoproteinA-I, and apolipoproteinB-100 levels in these patients resembled those in normolipidemic healthy subjects. The HDL subclass did not show a normal distribution and was characterized by the lower large-sized HDL(2b) contents and higher contents of small-sized preβ₁-HDL in CHD patients, compared to those in normolipidemic control subjects. Multiple stepwise regression analysis revealed that the severity of coronary stenosis, determined by the Gensini Score, was significantly and independently predicted by HDL(2b) and HDL(3b). Statin therapy was effective in modifying plasma lipids levels, but not adequate as a monotherapy to normalize the HDL subclass distribution phenotype of patients with CHD undergoing PCI. The HDL subclass distribution may aid in risk stratification, especially in patients with CHD and therapeutic LDL-C and HDL-C levels.

Switching to Pitavastatin in Statin-Treated Low HDL-C Patients Further Improves the Lipid Profile and Attenuates Minute Myocardial Damage

Background

The aim of this study is to determine the prevalence of minute myocardial damage (MMD) in already statin-treated dyslipidemic patients with a low high-density lipoprotein-cholesterol (HDL-C) level, and to evaluate whether pitavastatin could affect the lipid profiles and biomarkers reflecting myocardial stress and injury.

Methods

Twenty patients (15 men; age 66 ± 8) being treated with any statin but who had HDL-C < 40 mg/dL, were switched to pitavastatin (2 mg/day) treatment. The patient lipid profiles and the levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive troponin T (hsTnT), and high-sensitive C-reactive protein (hs-CRP) were evaluated for six months.

Results

At three months after the statin replacement, the HDL-C significantly increased from 37 ± 3 mg/dL to 40 ± 5 mg/dL (P < 0.05), and the low-density lipoprotein-cholesterol (LDL-C) and LDL-C/HDL-C ratio significantly reduced (100 ± 28 mg/dL to 86 ± 22 mg/dL, P < 0.05; 2.68 ± 0.67 to 2.17 ± 0.64, P < 0.05, respectively), and these changes were sustained for six months. In the whole study population, no significant changes were observed in the NT-proBNP, hsTnT, or hsCRP for six months. However, in 11 cases who showed a positive (> 0.003 ng/mL) hsTnT at baseline, a significant reduction in the hsTnT was observed (0.016 ± 0.020 ng/mL to 0.014 ± 0.020 ng/mL, P < 0.05), and its percent reduction significantly correlated with the percent increase in HDL-C (r = -0.68, P < 0.05).

Conclusions

MMD (positive hsTnT) was observed in more than half of patients with low HDL-C despite the administration of any statin, and the replacement of their previous statin with pitavastatin further improved their lipid profiles and led to better myocardial protection, possibly mediated via the elevation of the HDL-C level.

[Dysfunction of the blood-brain barrier during ischaemia: a therapeutic concern]

Since it was discovered and its brain-protective role characterized, the blood-brain barrier (BBB), through the permeability-restricting action of the brain capillary endothelial cells, has been representing a hurdle for 95% of new medical compounds targeting the central nervous system. Recently, a BBB dysfunction is being found in an increasing number of pathologies such as brain ischaemic stroke, whose only therapy consists in a pharmacological thrombolysis limited to a small percentage of the admitted patients, because of the toxical effects of thrombolytics. And since the clinical failure of promising neuroprotectants, numerous studies of brain ischaemia were carried out, with physiopathological or pharmacological approaches refocused on the BBB, whose structural complexity is now expanded to perivascular cells, all forming a functional unit named the neurovascular unit (NVU). Nevertheless, in spite of the numerous molecular mechanisms identified, the process of BBB dysfunction in the ischaemia/reperfusion cascade remains insufficiently established to explain the pleiotropic action exerted by new pharmacological compounds, possibly protecting the entire NVU and representing potential treatments.

Peroxisome proliferator-activated receptor α positively regulates complement C3 expression but inhibits tumor necrosis factor α-mediated activation of C3 gene in mammalian hepatic-derived cells

Complement C3 is a pivotal component of three cascades of complement activation. The liver is the main source of C3 in circulation and expression and secretion of C3 by hepatocytes is increased during acute inflammation. However, the mechanism of the regulation of the C3 gene in hepatocytes is not well elucidated. We showed that the C3 gene is the direct target for peroxisome proliferator-activated receptor α (PPARα) in human hepatoma HepG2 cells and mouse liver. Using PPARα siRNA and synthetic PPARα agonist WY-14643 and antagonist MK886 we showed that activation of PPARα results in up-regulation of C3 gene expression and protein secretion by HepG2 cells. The PPAR response element (PPRE), which is able to bind PPARα in vitro and in vivo, was found in the human C3 promoter. PPRE is conserved between human and mouse, and WY-14643 stimulates mouse C3 expression in the liver. TNFα increases C3 gene via NF-κB and, to a lesser extent, MEK1/2 signaling pathways, whereas TNFα-mediated stimulation of C3 protein secretion depends on activation of MEK1/2, p38, and JNK in HepG2 cells. Activation of PPARα abolishes TNFα-mediated up-regulation of C3 gene expression and protein secretion due to interference with NF-κB via PPRE-dependent mechanism in HepG2 cells. TNFα decreases PPARα protein content via NF-κB and MEK1/2 signaling pathways and inhibits PPARα binding with the human C3 promoter in HepG2 cells. These results suggest novel mechanism controlling C3 expression in hepatocytes during acute phase inflammation and demonstrate a crosstalk between PPARα and TNFα in the regulation of complement system.

Association of cholesteryl ester transfer protein mass with peripheral leukocyte count following statin therapy: a pilot study

BACKGROUND

HMG-CoA reductase inhibitors (statins) can effectively reduce serum low-density lipoprotein cholesterol (LDL-C) levels in the majority of patients at increased cardiovascular risk. However, some patients at increased cardiovascular risk have a high peripheral leukocyte count and this inflammatory marker has correlated with an increased incidence of coronary events. Recently, in a large clinical trial-based cohort, an increasing on-statin cholesteryl ester transfer protein (CETP) mass was inversely related to coronary events, particularly among those with a low serum LDL-C level. However, the role of the CETP mass in the development of atherosclerosis is still unclear.

OBJECTIVE

We investigated the possibility of whether the CETP mass was associated with the peripheral leukocyte count after intensive statin therapy, and whether the CETP mass was changed by switching statins.

METHODS

This study was an open-label lipid interventional study switching from atorvastatin to pitavastatin without a washout period. Between 1 April 2010 and 31 March 2011, 32 patients (mean age 64.0 ± 9.0 years, 63% male) with hypercholesterolemia receiving atorvastatin (10 mg/day) were enrolled. Next, they were switched to pitavastatin (2 mg/day) for 6 months. The peripheral leukocyte count, the CETP mass measured by enzyme-linked immunosorbent assay, and lipid parameters were measured at baseline and at follow-up. The type and dosage of concomitant drugs were not changed during the study periods.

RESULTS

The on-atorvastatin LDL-C level was well controlled with 94.4 ± 23.1 mg/dL, and peripheral leukocyte count was 6209 ± 1142 cells/μL. On atorvastatin therapy, the CETP mass correlated negatively with the peripheral leukocyte count (r = -0.418, p = 0.02). In univariate regression analysis, on-atorvastatin peripheral leukocyte count was significantly correlated with high-density lipoprotein cholesterol (β = -42.1, p = 0.008), triglycerides (β = 8.2, p = 0.005), and the CETP mass (β = -1296.3, p = 0.02). In a multivariate analysis after adjusting for traditional risk factors, the CETP mass remained an independent negative determinant of the peripheral leukocyte count (β = -1162, p = 0.02). By switching atorvastatin to pitavastatin, the CETP mass was significantly increased from 1.9 to 2.1 μg/mL (8.8%, p = 0.007), and the peripheral leukocyte count was significantly decreased from 6209 to 5778 cells/μL (-5.9%, p = 0.005). As a result, the relationship between CETP mass and peripheral leukocyte count after pitavastatin treatment was diminished (r = -0.276, p = 0.13). Moreover, the change in peripheral leukocyte count was negatively correlated with the change in the CETP mass (r = -0.39, p = 0.03), suggesting that a decreased CETP mass may be closely associated with an elevated peripheral leukocyte count in atorvastatin-treated patients.

CONCLUSION

The results suggest that residual cardiovascular risk after atorvastatin treatment may be associated with the CETP mass, which may be increased by switching to pitavastatin. Furthermore, a CETP mass-activating strategy may assist the therapeutic efficacy of statins.

Atorvastatin up-regulate toxicologically relevant genes in rainbow trout gills

There are large and increasing discharges of statins into the aquatic environment. Statins are cholesterol-lowering pharmaceuticals, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, an enzyme in the cholesterol synthesis pathway. Earlier studies have shown that statins will affect the expression of a range of genes in mammalian tissues and this group of pharmaceuticals has also been shown to affect membrane transporters. Changes in gene expression and ion transport in aquatic organisms may have dramatic consequences for the individual. The aim of the present study was to clarify whether waterborne exposure to a selected statin, atorvastatin, would affect gene expression in rainbow trout (Oncorhynchus mykiss) gill or liver or ion regulation in gills. Juvenile rainbow trout were exposed to two atorvastatin acid and atorvastatin lactone concentrations for 7 days (nominal concentrations 200 ng L(-1) and 10 μg L(-1)). The exposures caused up-regulated gene expression in gill, not liver, and only at the lowest concentration. Genes involved in membrane transport (pgp, mrp1), oxidative stress response (sod, mt), apoptosis (bax) and biotransformation (sult2b) were differentially expressed whereas the expression of genes involved in cholesterol biosynthesis (hmgr, fdps) or peroxisomal proliferation (ppar) were not affected. There were no significant changes in gill Na(+)/K(+) ATPase activity following exposure to atorvastatin. The pattern of differentially expressed genes in rainbow trout gills differ from responses previously observed in mammalian tissues following statin exposure.

Statins suppress apolipoprotein CIII-induced vascular endothelial cell activation and monocyte adhesion

Aims

Activation of vascular endothelial cells (ECs) contributes importantly to inflammation and atherogenesis. We previously reported that apolipoprotein CIII (apoCIII), found abundantly on circulating triglyceride-rich lipoproteins, enhances adhesion of human monocytes to ECs in vitro. Statins may exert lipid-independent anti-inflammatory effects. The present study examined whether statins suppress apoCIII-induced EC activation in vitro and in vivo.

Methods and results

Physiologically relevant concentrations of purified human apoCIII enhanced attachment of the monocyte-like cell line THP-1 to human saphenous vein ECs (HSVECs) or human coronary artery ECs (HCAECs) under both static and laminar shear stress conditions. This process mainly depends on vascular cell adhesion molecule-1 (VCAM-1), as a blocking VCAM-1 antibody abolished apoCIII-induced monocyte adhesion. ApoCIII significantly increased VCAM-1 expression in HSVECs and HCAECs. Pre-treatment with statins suppressed apoCIII-induced VCAM-1 expression and monocyte adhesion, with two lipophilic statins (pitavastatin and atorvastatin) exhibiting inhibitory effects at lower concentration than those of hydrophilic pravastatin. Nuclear factor κB (NF-κB) mediated apoCIII-induced VCAM-1 expression, as demonstrated via loss-of-function experiments, and pitavastatin treatment suppressed NF-κB activation. Furthermore, in the aorta of hypercholesterolaemic Ldlr^−/− mice, pitavastatin administration in vivo suppressed VCAM-1 mRNA and protein, induced by apoCIII bolus injection. Similarly, in a subcutaneous dorsal air pouch mouse model of leucocyte recruitment, apoCIII injection induced F4/80+ monocyte and macrophage accumulation, whereas pitavastatin administration reduced this effect.

Conclusions

These findings further establish the direct role of apoCIII in atherogenesis and suggest that anti-inflammatory effects of statins could improve vascular disease in the population with elevated plasma apoCIII.

Reverse cholesterol transport in familial hypercholesterolemia

PURPOSE OF REVIEW

Familial hypercholesterolemia is characterized by a major elevation in circulating LDL-cholesterol levels, cholesterol deposition within the arterial wall and an increased risk of premature coronary artery disease. The reverse cholesterol transport (RCT) is now considered as a key process that protects against development of atherosclerosis. The major antiatherogenic action of HDL particles is intimately linked to their determinant role in RCT pathway. However, the steady-sate of HDL-cholesterol levels does not represent the optimal marker to evaluate the efficiency of the RCT in all circumstances.

RECENT FINDINGS

By using ex-vivo systems for the evaluation of the efficacy of RCT a strong inverse relationship between HDL efflux capacity from macrophages and atherosclerosis progression has been demonstrated. Low HDL-C phenotype observed in familial hypercholesterolemia patients is associated with defective capacities of HDL particles to mediate major steps of the centripetal movement of cholesterol from peripheral cells to feces. However, current available treatment used to reduce LDL-C to therapeutic goals does not correct altered functions of HDL particles in humans.

SUMMARY

In the context of familial hypercholesterolemia, a growing body of evidence suggests that impaired efficacy of the RCT pathway contributes significantly to the progression of atherosclerosis.

Pleiotropic effects of pitavastatin

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are established first line treatments for hypercholesterolaemia. In addition to the direct effects of statins in reducing concentrations of atherogenic low density lipoprotein cholesterol (LDL-C), several studies have indicated that the beneficial effects of statins may be due to some of their cholesterol-independent, multiple (pleiotropic) effects which may differ between different members of the class. Pitavastatin is a novel synthetic lipophilic statin that has a number of pharmacodynamic and pharmacokinetic properties distinct from those of other statins, which may underlie its potential pleiotropic benefits in reducing cardiovascular risk factors. This review examines the principal pleiotropic effects of pitavastatin on endothelial function, vascular inflammation, oxidative stress and thrombosis. The article is based on a systematic literature search carried out in December 2010, together with more recent relevant publications where appropriate. The available data from clinical trials and in vitro and animal studies suggest that pitavastatin is not only effective in reducing LDL-C and triglycerides, but also has a range of other effects. These include increasing high density lipoprotein cholesterol, decreasing markers of platelet activation, improving cardiac, renal and endothelial function, and reducing endothelial stress, lipoprotein oxidation and, ultimately, improving the signs and symptoms of atherosclerosis. It is concluded that the diverse pleiotropic actions of pitavastatin may contribute to reducing cardiovascular morbidity and mortality beyond that achieved through LDL-C reduction.

Endothelial cells and astrocytes: a concerto en duo in ischemic pathophysiology

The neurovascular/gliovascular unit has recently gained increased attention in cerebral ischemic research, especially regarding the cellular and molecular changes that occur in astrocytes and endothelial cells. In this paper we summarize the recent knowledge of these changes in association with edema formation, interactions with the basal lamina, and blood-brain barrier dysfunctions. We also review the involvement of astrocytes and endothelial cells with recombinant tissue plasminogen activator, which is the only FDA-approved thrombolytic drug after stroke. However, it has a narrow therapeutic time window and serious clinical side effects. Lastly, we provide alternative therapeutic targets for future ischemia drug developments such as peroxisome proliferator- activated receptors and inhibitors of the c-Jun N-terminal kinase pathway. Targeting the neurovascular unit to protect the blood-brain barrier instead of a classical neuron-centric approach in the development of neuroprotective drugs may result in improved clinical outcomes after stroke.

Targeting NADPH oxidases in vascular pharmacology

Oxidative stress is a molecular dysregulation in reactive oxygen species (ROS) metabolism, which plays a key role in the pathogenesis of atherosclerosis, vascular inflammation and endothelial dysfunction. It is characterized by a loss of nitric oxide (NO) bioavailability. Large clinical trials such as HOPE and HPS have not shown a clinical benefit of antioxidant vitamin C or vitamin E treatment, putting into question the role of oxidative stress in cardiovascular disease. A change in the understanding of the molecular nature of oxidative stress has been driven by the results of these trials. Oxidative stress is no longer perceived as a simple imbalance between the production and scavenging of ROS, but as a dysfunction of enzymes involved in ROS production. NADPH oxidases are at the center of these events, underlying the dysfunction of other oxidases including eNOS uncoupling, xanthine oxidase and mitochondrial dysfunction. Thus NADPH oxidases are important therapeutic targets. Indeed, HMG-CoA reductase inhibitors (statins) as well as drugs interfering with the renin-angiotensin-aldosterone system inhibit NADPH oxidase activation and expression. Angiotensin-converting enzyme (ACE) inhibitors, AT1 receptor antagonists (sartans) and aliskiren, as well as spironolactone or eplerenone, have been discussed. Molecular aspects of NADPH oxidase regulation must be considered, while thinking about novel pharmacological targeting of this family of enzymes consisting of several homologs Nox1, Nox2, Nox3, Nox4 and Nox5 in humans. In order to properly design trials of antioxidant therapies, we must develop reliable techniques for the assessment of local and systemic oxidative stress. Classical antioxidants could be combined with novel oxidase inhibitors. In this review, we discuss NADPH oxidase inhibitors such as VAS2870, VAS3947, GK-136901, S17834 or plumbagin. Therefore, our efforts must focus on generating small molecular weight inhibitors of NADPH oxidases, allowing the selective inhibition of dysfunctional NADPH oxidase homologs. This appears to be the most reasonable approach, potentially much more efficient than non-selective scavenging of all ROS by the administration of antioxidants.

Rosuvastatin does not affect human apolipoprotein A-I expression in genetically modified mice: a clue to the disputed effect of statins on HDL

BACKGROUND AND PURPOSE

Besides a significant reduction of low-density lipoprotein (LDL) cholesterol, statins moderately increase high-density lipoprotein (HDL) levels. In vitro studies have indicated that this effect may be the result of an increased expression of apolipoprotein (apo)A-I, the main protein component of HDL. The aim of the present study was to investigate in vivo the effect of rosuvastatin on apoA-I expression and secretion in a transgenic mouse model for human apoA-I.

EXPERIMENTAL APPROACH

Human apoA-I transgenic mice were treated for 28 days with 5, 10 or 20 mg·kg(-1) ·day(-1) of rosuvastatin, the most effective statin in raising HDL levels. Possible changes of apoA-I expression by treatment were investigated by quantitative real-time RT-PCR on RNA extracted from mouse livers. The human apoA-I secretion rate was determined in primary hepatocytes isolated from transgenic mice from each group after treatment.

KEY RESULTS

Rosuvastatin treatment with 5 and 10 mg·kg(-1) ·day(-1) did not affect apoA-I plasma levels, whereas a significant decrease was observed in mice treated with 20 mg·kg(-1) ·day(-1) of rosuvastatin (-16%, P < 0.01). Neither relative hepatic mRNA concentrations of apoA-I nor apoA-I secretion rates from primary hepatocytes were influenced by rosuvastatin treatment at each tested dose.

CONCLUSIONS AND IMPLICATIONS

In human apoA-I transgenic mice, rosuvastatin treatment does not increase either apoA-I transcription and hepatic secretion, or apoA-I plasma levels. These results support the hypothesis that other mechanisms may account for the observed HDL increase induced by statin therapy in humans.

AS601245, an Anti-Inflammatory JNK Inhibitor, and Clofibrate Have a Synergistic Effect in Inducing Cell Responses and in Affecting the Gene Expression Profile in CaCo-2 Colon Cancer Cells

PPARαs are nuclear receptors highly expressed in colon cells. They can be activated by the fibrates (clofibrate, ciprofibrate etc.) used to treat hyperlipidemia. Since PPARα transcriptional activity can be negatively regulated by JNK, the inhibition of JNK activity could increase the effectiveness of PPARα ligands. We analysed the effects of AS601245 (a JNK inhibitor) and clofibrate alone or in association, on proliferation, apoptosis, differentiation and the gene expression profile of CaCo-2 human colon cancer cells. Proliferation was inhibited in a dose-dependent way by clofibrate and AS601245. Combined treatment synergistically reduced cell proliferation, cyclin D1 and PCNA expression and induced apoptosis and differentiation. Reduction of cell proliferation, accompanied by the modulation of p21 expression was observed in HepG2 cells, also. Gene expression analysis revealed that some genes were highly modulated by the combined treatment and 28 genes containing PPRE were up-regulated, while clofibrate alone was ineffective. Moreover, STAT3 signalling was strongly reduced by combined treatment. After combined treatment, the binding of PPARα to PPRE increased and paralleled with the expression of the PPAR coactivator MED1. Results demonstrate that combined treatment increases the effectiveness of both compounds and suggest a positive interaction between PPARα ligands and anti-inflammatory agents in humans.

PPARα mediates the anti-inflammatory effect of simvastatin in an experimental model of zymosan-induced multiple organ failure

BACKGROUND AND PURPOSE

Zymosan-induced non-septic shock is a multi-factorial pathology that involves several organs including the kidneys, liver and lungs. Its complexity and diversity presents a continuing therapeutic challenge. Given their pleiotropic effect, statins could be beneficial in non-septic shock. One of the molecular mechanisms underlying the anti-inflammatory effect of statins involves the peroxisome proliferator-activated receptor (PPAR) α. We used a zymosan-induced non-septic shock experimental model to investigate the role of PPARα in the anti-inflammatory effects of simvastatin.

EXPERIMENTAL APPROACH

Effects of simvastatin (5 or 10 mg·kg(-1) i.p.) were analysed in PPARα knock-out (KO) and PPARα wild type (WT) mice after zymosan or vehicle administration. Organ injury in lung, liver, kidney and intestine was evaluated by immunohistology. PPARα mRNA expression and nuclear factor-κB activation were evaluated in all experimental groups, 18 h after study onset. Cytokine levels were measured in plasma, and nitrite/nitrate in plasma and peritoneal exudate. Nitric oxide synthase, nitrotyrosine and poly ADP-ribose were localized by immunohistochemical methods.

KEY RESULTS

Simvastatin significantly and dose-dependently increased the zymosan-induced expression of PPARα levels in all tissues analysed. It also dose-dependently reduced systemic inflammation and the organ injury induced by zymosan in lung, liver, intestine and kidney. These effects were observed in PPARαWT mice and in PPARαKO mice.

CONCLUSIONS AND IMPLICATIONS

Simvastatin protected against the molecular and cellular damage caused by systemic inflammation in our experimental model. Our results also provide new information regarding the role of PPARα in the anti-inflammatory effects of statins.