Increasing apoA-I production as a target for CHD risk reduction

Emerging therapies in Friedreich's Ataxia

INTRODUCTION

Friedreich's ataxia (FRDA) is a progressive, neurodegenerative disease that results in gait and limb ataxia, diabetes, cardiac hypertrophy, and scoliosis. At the cellular level, FRDA results in the deficiency of frataxin, a mitochondrial protein that plays a vital role in iron homeostasis and amelioration of oxidative stress. No cure currently exists for FRDA, but exciting therapeutic developments which target different parts of the pathological cascade are on the horizon.

AREAS COVERED

Areas covered include past and emerging therapies for FRDA, including antioxidants and mitochondrial-related agents, nuclear factor erythroid-derived 2-related factor 2 (Nrf2) activators, deuterated polyunsaturated fatty acids, iron chelators, histone deacetylase (HDAC) inhibitors, trans-activator of transcription (TAT)-frataxin, interferon gamma (IFNγ), erythropoietin, resveratrol, gene therapy, and anti-sense oligonucleotides (ASOs), among others.

EXPERT OPINION

While drug discovery has been challenging, new and exciting prospective treatments for FRDA are currently on the horizon, including pharmaceutical agents and gene therapy. Agents that enhance mitochondrial function, such as Nrf2 activators, dPUFAs and catalytic antioxidants, as well as novel methods of frataxin augmentation and genetic modulation will hopefully provide treatment for this devastating disease.

Search for Natural Compounds That Increase Apolipoprotein A-I Transcription in HepG2 Cells: Specific Attention for BRD4 Inhibitors

Although increasing apolipoprotein A‐I (apoA‐I) might lower the cardiovascular disease risk, knowledge on natural compounds that elevate apoA‐I transcription is limited. Therefore, the aim of this study was to discover natural compounds that increase apoA‐I transcription in HepG2 cells. Since BRD4 inhibition is known to elevate apoA‐I transcription, we focused on natural BRD4 inhibitors. For this, the literature was screened for compounds that might increase apoA‐I and or inhibit BRD4. This resulted in list A, (apoA‐I increasers with unknown BRD4 inhibitor capacity), list B (known BRD4 inhibitors that increase apoA‐I), and list C (BRD4 inhibitors with unknown effect on apoA‐I). These compounds were compared with the compounds in two natural compound databases. This resulted in (1) a common substructure (ethyl‐benzene) in 60% of selected BRD4‐inhibitors, and (2) four compounds that increased ApoA‐I: hesperetin, equilenin, 9(S)‐HOTrE, and cymarin. Whether these increases are regulated via BRD4 inhibition and the ethyl‐benzene structure inhibits BRD4 requires further study.

Low apolipoprotein A-I levels in Friedreich's ataxia and in frataxin-deficient cells: Implications for therapy

Friedreich's ataxia (FA) is an autosomal recessive neurodegenerative disorder, which results primarily from reduced expression of the mitochondrial protein frataxin. FA has an estimated prevalence of one in 50,000 in the population, making it the most common hereditary ataxia. Paradoxically, mortality arises most frequently from cardiomyopathy and cardiac failure rather than from neurological effects. Decreased high-density lipoprotein (HDL) and apolipoprotein A-I (ApoA-l) levels in the general population are associated with an increased risk of mortality from cardiomyopathy and heart failure. However, the pathophysiology of heart disease in FA is non-vascular and there are conflicting data on HDL-cholesterol in FA. Two studies have shown a decrease in HDL-cholesterol compared with controls and two have shown there was no difference between FA and controls. One also showed that there was no difference in serum Apo-A-I levels in FA when compared with controls. Using a highly specific stable isotope dilution mass spectrometry-based assay, we demonstrated a 21.6% decrease in serum ApoA-I in FA patients (134.8 mg/dL, n = 95) compared with non-affected controls (172.1 mg/dL, n = 95). This is similar to the difference in serum ApoA-I levels between non-smokers and tobacco smokers. Knockdown of frataxin by > 70% in human hepatoma HepG2 cells caused a 20% reduction in secreted ApoA-I. Simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor caused a 200% increase in HMG-CoA in the control HepG2 cells with a similar increase in the frataxin knockdown HepG2 cells, back to levels found in the control cells. There was a concomitant 20% increase in secreted ApoA-I to levels found in the control cells that were treated with simvastatin. This study provides compelling evidence that ApoA-I levels are reduced in FA patients compared with controls and suggest that statin treatment would normalize the ApoA-I levels.

Dietary Strategies and Novel Pharmaceutical Approaches Targeting Serum ApoA-I Metabolism: A Systematic Overview

The incidence of CHD is still increasing, which underscores the need for new preventive and therapeutic approaches to decrease CHD risk. In this respect, increasing apoA-I concentrations may be a promising approach, especially through increasing apoA-I synthesis. This review first provides insight into current knowledge on apoA-I production, clearance, and degradation, followed by a systematic review of dietary and novel pharmacological approaches to target apoA-I metabolism. For this, a systematic search was performed to identify randomized controlled intervention studies that examined effects of whole foods and (non)nutrients on apoA-I metabolism. In addition, novel pharmacological approaches were searched for, which were specifically developed to target apoA-I metabolism. We conclude that both dietary components and pharmacological approaches can be used to increase apoA-I concentrations or functionality. For the dietary components in particular, more knowledge about the underlying mechanisms is necessary, as increasing apoA-I per se does not necessarily translate into a reduced CHD risk.

Pharmacokinetics, pharmacodynamics and safety of CKD-519, a CETP inhibitor, in healthy subjects

CKD-519 is a selective and potent cholesteryl ester transfer protein (CETP) inhibitor being developed for the treatment of dyslipidemia to raise high-density lipoprotein cholesterol. We investigated the safety, tolerability, pharmacokinetics, and pharmacodynamics of single doses of CKD-519 in healthy adult subjects. A randomized, double-blinded, placebo-controlled, single ascending dose study was performed. Eight healthy subjects were enrolled in each CKD-519 dose group (25, 50, 100, 200, or 400 mg) and randomized to CKD-519 (n=6) or matching placebo (n=2). CKD-519 reached the maximum plasma concentration (C_max) at 5–6 h post-dose, and had a long terminal half-life ranging between 40–70 h. The area under the plasma concentration–time curve (AUC) and C_max increased with the dose, however, C_max and AUC normalized by dose decreased with each incremental dose. CETP activity decreased with dose, and the maximum decrease (63%–83%) was observed at 6–8 h post-dose. A sigmoid E_max model best described the relationship between CKD-519 plasma concentrations and CETP activity with an EC₅₀ of 17.3 ng/mL. Overall, 11 adverse events (AEs) were observed. All AEs were mild or moderate in intensity, and resolved without any complications. There were no clinically significant effects on blood pressure. In conclusion, single doses of CKD-519 up to 400 mg were well tolerated and showed potent inhibition of CETP activity.

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.

The improvement of large High-Density Lipoprotein (HDL) particle levels, and presumably HDL metabolism, depend on effects of low-carbohydrate diet and weight loss

Depressed levels of atheroprotective large HDL particles are common in obesity and cardiovascular disease (CVD). Increases in large HDL particles are favourably associated with reduced CVD event risk and coronary plaque burden. The objective of the study is to compare the effectiveness of low-carbohydrate diets and weight loss for increasing blood levels of large HDL particles at 1 year. This study was performed by screening for body mass index (BMI) and metabolic syndrome in 160 consecutive subjects referred to our out-patient Metabolic Unit in South Italy. We administered dietary advice to four small groups rather than individually. A single team comprised of a dietitian and physician administered diet-specific advice to each group. Large HDL particles at baseline and 1 year were measured using two-dimensional gel electrophoresis. Dietary intake was assessed via 3-day diet records. Although 1-year weight loss did not differ between diet groups (mean 4.4 %), increases in large HDL particles paralleled the degree of carbohydrate restriction across the four diets (p<0.001 for trend). Regression analysis indicated that magnitude of carbohydrate restriction (percentage of calories as carbohydrate at 1 year) and weight loss were each independent predictors of 1-year increases in large HDL concentration. Changes in HDL cholesterol concentration were modestly correlated with changes in large HDL particle concentration (r=0.47, p=.001). In conclusion, reduction of excess dietary carbohydrate and body weight improved large HDL levels. Comparison trials with cardiovascular outcomes are needed to more fully evaluate these findings.

Serum apolipoprotein A-1 quantification by LC-MS with a SILAC internal standard reveals reduced levels in smokers

Background:

Absolute quantification of protein biomarkers such as serum apolipoprotein A1 by both immunoassays and LC–MS can provide misleading results.

Results:

Recombinant ApoA-1 internal standard was prepared using stable isotope labeling by amino acids in cell culture with [¹³C₆¹⁵N₂]-lysine and [¹³C₉¹⁵N₁]-tyrosine in human cells. A stable isotope dilution LC–MS method for serum ApoA-1 was validated and levels analyzed for 50 nonsmokers and 50 smokers.

Conclusion:

The concentration of ApoA-1 in nonsmokers was 169.4 mg/dl with an 18.4% reduction to 138.2 mg/dl in smokers. The validated assay will have clinical utility for assessing effects of smoking cessation and therapeutic or dietary interventions in high-risk populations.

Proteomic analysis of plasma after branched chain enriched mixture supplementation in mice

Background

Branched chain amino acid (BCAA) supplementation is a recently identified strategy to promote longevity in mice. A proteomic approach was used to identify proteins which are differentially expressed in the sera of mice following supplementation with selected branched chain amino acid enriched mixture (BCAAem).

Findings

12 male mice (C57Bl6, 9 months-old) were randomly assigned to unsupplemented (Control, n = 6) and supplemented (BCAA, n = 6, 0.1 mg/gr/day in drink water for 4 weeks). At the end of treatment total plasma samples from Control and BCAAem mice were separated by two-dimensional gel electrophoresis (2-DE). After staining, the gels were imaged and differential protein expression patterns were interrogated using image analysis software. Spots showing a different expression level were identified through a comparison with 2D maps found in databases officially recognized (ExPASy).

Master gels of Control and BCAA mice exhibited slightly different 2-DE patterns as only 10 spots out of 500 appeared differentially expressed: 8 were upregulated (corresponding to Apolipoprotein A-I (APOA1), Complement factor B, Complement C3, Immunoglobulin light chain) and 2 appeared downregulated (Alpha-1-antitrypsin and unknown).

Conclusions

Supplementation with BCAAem in mice results in a slight perturbation of the host serum proteome. Of particular interest is the increased Apolipoprotein A-I (APOAI) following treatment.

Elimination of endoplasmic reticulum stress and cardiovascular, type 2 diabetic, and other metabolic diseases

Multiple factors including unhealthy living habits influence the life-maintaining functions of the endoplasmic reticulum (ER) and induce ER stress and metabolic abnormalities. The ER responds to the disturbances by activating mechanisms that increase the capacity to eliminate ER stress. This article elucidates the effects of ER activation that eliminates both ER stress and associated cardiovascular, type 2 diabetic (DM2), and other metabolic diseases. ER-activating compounds eliminate ER stress by lowering elevated cholesterol, regress atherosclerosis, decrease cardiovascular mortality, reduce blood glucose and insulin, and, together with the normalization of glucose-insulin homeostasis, remove insulin resistance, pancreatic β-cell failure, and DM2. A deficient cytochrome P450 activity in hepatic ER leads to cholesterol accumulation that induces stress and xanthoma formation, whereas P450-activating therapy up-regulates apolipoprotein AI and LDLR genes, down-regulates apolipoprotein B gene, and produces an antiatherogenic plasma lipoprotein profile. The ER activation reduces the stress also by eliminating hepatic fat and converting saturated fatty acids (FAs) to unsaturated FAs. Cognitive processes require gene expression modification, and preclinical studies indicate that ER-activating therapy improves cognition. Promotion of healthy lifestyle choices and indicated therapies are key factors in the prevention and elimination of ER stress and associated global health problems.

Effects of Glycyrrhizic Acid on Peroxisome Proliferator-Activated Receptor Gamma (PPARgamma), Lipoprotein Lipase (LPL), Serum Lipid and HOMA-IR in Rats

Studies on ligand binding potential of glycyrrhizic acid, a potential agonist to PPARgamma, displayed encouraging results in amelioration of metabolic syndrome. The regulation of gene cassettes by PPARgamma affects glucose homeostasis, lipid, lipoprotein metabolism and adipogenesis. This study was performed to determine the effects of GA on total PPARgamma and LPL expression levels, lipid parameters and HOMA-IR. Oral administration of 100 mg/kg GA for 24 hours resulted in an increase in insulin sensitivity with decreases in blood glucose, serum insulin and HOMA-IR. Improvement in serum lipid parameters was also observed with a decrease in triacylglycerol, total cholesterol and LDL-cholesterol and an elevation in HDL-cholesterol. GA administration also resulted in up-regulation of total PPARgamma and LPL expression levels in the visceral and subcutaneous adipose tissues, abdominal and quadriceps femoris muscles, as well as liver and kidney, with a significant up-regulation only in the visceral adipose tissue, abdominal and quadriceps femoris muscles. Thus, oral administration of 100 mg/kg GA for 24 hours improved insulin sensitivity and lipid profiles and induced upregulation of total PPARgamma and LPL expression levels in all studied tissues.

Gene-activation mechanisms in the regression of atherosclerosis, elimination of diabetes type 2, and prevention of dementia

Atherosclerotic vascular disease, diabetes mellitus (DM) and dementia are major global health problems. Both endogenous and exogenous factors activate genes functioning in biological processes. This review article focuses on gene-activation mechanisms that regress atherosclerosis, eliminate DM type 2 (DM2), and prevent cognitive decline and dementia. Gene-activating compounds upregulating functions of liver endoplasmic reticulum (ER) and affecting lipid and protein metabolism, increase ER size through membrane synthesis, and produce an antiatherogenic plasma lipoprotein profile. Numerous gene-activators regress atherosclerosis and reduce the occurrence of atherosclerotic disease. The gene-activators increase glucose disposal rate and insulin sensitivity and, by restoring normal glucose and insulin levels, remove metabolic syndrome and DM2. Patients with DM2 show an improvement of plasma lipoprotein profile and glucose tolerance together with increase in liver phospholipid (PL) and cytochrome (CYP) P450. The gene-activating compounds induce hepatic protein and PL synthesis, and upregulate enzymes including CYPs and glucokinase, nuclear receptors, apolipoproteins and ABC (ATP-binding cassette) transporters. They induce reparation of ER structures and eliminate consequences of ER stress. Healthy living habits activate mechanisms that maintain high levels of HDL and apolipoprotein AI, promote health, and prevent cognitive decline and dementia. Agonists of liver X receptor (LXR) reduce amyloid in brain plaques and improve cognitive performance in mouse models of Alzheimer's disease. The gene activation increases the capacity to withstand cellular stress and to repair cellular damage and increases life span. Life free of major health problems and in good cognitive health promotes well-being and living a long and active life.

Emerging options in the treatment of dyslipidemias: a bright future?

INTRODUCTION

Hypercholesterolemia is a major risk factor for cardiovascular disease (CVD). Low-density lipoprotein cholesterol (LDL-C) reduction has been demonstrated to decrease CVD-related morbidity and mortality. However, several patients do not reach LDL-C target levels with the currently available lipid lowering agents, particularly statins. Lipid and non-lipid parameters other than LDL-C may account for the residual CVD risk after adequate LDL-C lowering with statins.

AREAS COVERED

This review focuses on the efficacy and safety of emerging drugs aiming at high-density lipoprotein cholesterol (HDL-C) elevation (i.e., recombinant or plasma-derived wild-type apolipoprotein (apo) A-I, apo A-I mimetic peptides, reconstituted mutant HDL, partially delipidated HDL and cholesterol ester transfer protein inhibitors), microsomal triglyceride transfer protein inhibitors and antisense oligonucleotides.

EXPERT OPINION

Several lipid modifying agents in development may potently reduce the residual CVD risk. Ongoing and future studies with clinical outcomes will clarify their efficacy in clinical practice.

Gene activation regresses atherosclerosis, promotes health, and enhances longevity

Background

Lifestyle factors and pharmacological compounds activate genetic mechanisms that influence the development of atherosclerotic and other diseases. This article reviews studies on natural and pharmacological gene activation that promotes health and enhances longevity.

Results

Living habits including healthy diet and regular physical activity, and pharmacotherapy, upregulate genes encoding enzymes and apolipoprotein and ATP-binding cassette transporters, acting in metabolic processes that promote health and increase survival. Cytochrome P450-enzymes, physiological factors in maintaining cholesterol homeostasis, generate oxysterols for the elimination of surplus cholesterol. Hepatic CTP:phosphocholine cytidylyltransferase-α is an important regulator of plasma HDL-C level. Gene-activators produce plasma lipoprotein profile, high HDL-C, HDL₂-C and HDL-C/cholesterol ratio, which is typical of low risk of atherosclerotic disease, and also of exceptional longevity together with reduced prevalence of cardiovascular, metabolic and other diseases. High HDL contributes to protection against inflammation, oxidation and thrombosis, and associates with good cognitive function in very old people. Avoiding unhealthy stress and managing it properly promotes health and increases life expectancy.

Conclusions

Healthy living habits and gene-activating xenobiotics upregulate mechanisms that produce lipoprotein pattern typical of very old people and enhance longevity. Lipoprotein metabolism and large HDL₂ associate with the process of living a very long life. Major future goals for health promotion are the improving of commitment to both wise lifestyle choices and drug therapy, and further the developing of new and more effective and well tolerated drugs and treatments.

The association of 83 plasma proteins with CHD mortality, BMI, HDL-, and total-cholesterol in men: applying multivariate statistics to identify proteins with prognostic value and biological relevance

In this study, we applied the multivariate statistical tool Partial Least Squares (PLS) to analyze the relative importance of 83 plasma proteins in relation to coronary heart disease (CHD) mortality and the intermediate end points body mass index, HDL-cholesterol and total cholesterol. From a Dutch monitoring project for cardiovascular disease risk factors, men who died of CHD between initial participation (1987-1991) and end of follow-up (January 1, 2000) (N = 44) and matched controls (N = 44) were selected. Baseline plasma concentrations of proteins were measured by a multiplex immunoassay. With the use of PLS, we identified 15 proteins with prognostic value for CHD mortality and sets of proteins associated with the intermediate end points. Subsequently, sets of proteins and intermediate end points were analyzed together by Principal Components Analysis, indicating that proteins involved in inflammation explained most of the variance, followed by proteins involved in metabolism and proteins associated with total-C. This study is one of the first in which the association of a large number of plasma proteins with CHD mortality and intermediate end points is investigated by applying multivariate statistics, providing insight in the relationships among proteins, intermediate end points and CHD mortality, and a set of proteins with prognostic value.

Lipoprotein lipase expression, serum lipid and tissue lipid deposition in orally-administered glycyrrhizic acid-treated rats

Background

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities comprising visceral obesity, dyslipidaemia and insulin resistance (IR). With the onset of IR, the expression of lipoprotein lipase (LPL), a key regulator of lipoprotein metabolism, is reduced. Increased activation of glucocorticoid receptors results in MetS symptoms and is thus speculated to have a role in the pathophysiology of the MetS. Glycyrrhizic acid (GA), the bioactive constituent of licorice roots (Glycyrrhiza glabra) inhibits 11β-hydroxysteroid dehydrogenase type 1 that catalyzes the activation of glucocorticoids. Thus, oral administration of GA is postulated to ameliorate the MetS.

Results

In this study, daily oral administration of 50 mg/kg of GA for one week led to significant increase in LPL expression in the quadriceps femoris (p < 0.05) but non-significant increase in the abdominal muscle, kidney, liver, heart and the subcutaneous and visceral adipose tissues (p > 0.05) of the GA-treated rats compared to the control. Decrease in adipocyte size (p > 0.05) in both the visceral and subcutaneous adipose tissue depots accompanies such selective induction of LPL expression. Consistent improvement in serum lipid parameters was also observed, with decrease in serum free fatty acid, triacylglycerol, total cholesterol and LDL-cholesterol but elevated HDL-cholesterol (p > 0.05). Histological analysis using tissue lipid staining with Oil Red O showed significant decrease in lipid deposition in the abdominal muscle and quadriceps femoris (p < 0.05) but non-significant decrease in the heart, kidney and liver (p > 0.05).

Conclusion

Results from this study may imply that GA could counteract the development of visceral obesity and improve dyslipidaemia via selective induction of tissue LPL expression and a positive shift in serum lipid parameters respectively, and retard the development of IR associated with tissue steatosis.

Global relationship between the proteome and transcriptome of human skeletal muscle

Skeletal muscle is one of the largest tissues in the human body. Changes in mRNA and protein abundance in this tissue are central to a large number of metabolic and other disorders, including, commonly, insulin resistance. Proteomic and microarray analyses are important approaches for gaining insight into the molecular and biochemical basis for normal and pathophysiological conditions. With the use of vastus lateralis muscle obtained from two groups of healthy, nonobese subjects, we performed a detailed comparison of the muscle proteome, obtained by HPLC-ESI-MS/MS, with the muscle transcriptome, obtained using oligonucleotide microarrays. HPLC-ESI-MS/MS analysis identified 507 unique proteins as present in four out of six subjects, while 5193 distinct transcripts were called present by oligonucleotide microarrays from four out of six subjects. The majority of the proteins identified by mass spectrometry also had their corresponding transcripts detected by microarray analysis, although 73 proteins were only identified in the proteomic analysis. Reflecting the high abundance of mitochondria in skeletal muscle, 30% of proteins detected were attributed to the mitochondrion, as compared to only 9% of transcripts. On the basis of Gene Ontology annotations, proteins assigned to mitochondrial inner membrane, mitochondrial envelope, structural molecule activity, electron transport, as well as generation of precursor metabolites and energy, had more corresponding transcripts detected than would be expected by chance. On the contrary, proteins assigned to Golgi apparatus, extracellular region, lyase activity, kinase activity, and protein modification process had fewer corresponding transcripts detected than would be expected by chance. In conclusion, these results provide the first global comparison of the human skeletal muscle proteome and transcriptome to date. These data show that a combination of proteomic and transcriptic analyses will provide data that can be used to test hypotheses regarding the pathogenesis of muscle disorders as well as to generate observational data that can be used to form novel hypotheses.

Synthetic HDL as a new treatment for atherosclerosis regression: has the time come?

Plasma high-density lipoprotein cholesterol (HDL-C) has received considerable attention as a potential therapeutic target to further reduce cardiovascular events in the statin era. One therapeutic approach to enhance HDL-mediated atheroprotection involves the use of small, synthetic and orally-active compounds that substantially raise plasma HDL-C levels. However, doubts on the clinical benefit achievable with such treatments have been raised by the premature termination of a large Phase III trial with torcetrapib, the most potent and furthest developed HDL-C raising compound, because of excess mortality in patients receiving the drug. The alternative is the direct administration of synthetic HDL (sHDL), discoidal lipoprotein particles which mimic most, if not all, of the atheroprotective properties of plasma HDL. Short-term treatments with sHDL of different composition caused consistent and remarkable reductions of atheroma volume in patients with acute coronary syndromes (ACS). Although at early stages of drug development, sHDL hold vast promise for plaque stabilization/regression, and cardiovascular event reduction.

Spotlight on HDL-raising therapies: insights from the torcetrapib trials

Subnormal levels of HDL cholesterol constitute a major cardiovascular risk factor. Inhibitors of cholesteryl ester transfer protein (CETP) are presently the most potent HDL-raising agents. Torcetrapib was the first CETP inhibitor to enter a large-scale, prospective, placebo-controlled interventional trial, which was prematurely terminated in December 2006 because of excess cardiovascular and noncardiovascular mortality in the active treatment group. Therapy with torcetrapib was associated with considerable increases in aldosterone level and blood pressure and changes in serum electrolytes indicative of mineralocorticoid excess. These findings indicate that torcetrapib has off-target toxic effects unrelated to HDL raising that involve the activation of mineralocorticoid receptors by aldosterone and result in the induction of hypertension. In contrast with torcetrapib, other CETP inhibitors such as JTT-705 and MK-825 do not increase blood pressure in humans, an observation which discounts a class effect. The available data do not, however, exclude potential adverse effects of CETP inhibition such as the generation of HDL particles that have deficient biological activities and a deleterious impact on reverse cholesterol transport and steroid metabolism. Normalization of both defective HDL function and diminished HDL levels should, therefore, be the focus of pharmacological HDL raising in future studies.