Ezetimibe, cardiovascular risk and atherogenic dyslipidaemia

Development of calcific aortic valve disease: Do we know enough for new clinical trials?

Calcific aortic valve disease (CAVD), previously thought to represent a passive degeneration of the valvular extracellular matrix (VECM), is now regarded as an intricate multistage disorder with sequential yet intertangled and interacting underlying processes. Endothelial dysfunction and injury, initiated by disturbed blood flow and metabolic disorders, lead to the deposition of low-density lipoprotein cholesterol in the VECM further provoking macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines. Such changes in the valvular homeostasis induce differentiation of normally quiescent valvular interstitial cells (VICs) into synthetically active myofibroblasts producing excessive quantities of the VECM and proteins responsible for its remodeling. As a result of constantly ongoing degradation and re-deposition, VECM becomes disorganised and rigid, additionally potentiating myofibroblastic differentiation of VICs and worsening adaptation of the valve to the blood flow. Moreover, disrupted and excessively vascularised VECM is susceptible to the dystrophic calcification caused by calcium and phosphate precipitating on damaged collagen fibers and concurrently accompanied by osteogenic differentiation of VICs. Being combined, passive calcification and biomineralisation synergistically induce ossification of the aortic valve ultimately resulting in its mechanical incompetence requiring surgical replacement. Unfortunately, multiple attempts have failed to find an efficient conservative treatment of CAVD; however, therapeutic regimens and clinical settings have also been far from the optimal. In this review, we focused on interactions and transitions between aforementioned mechanisms demarcating ascending stages of CAVD, suggesting a predisposing condition (bicuspid aortic valve) and drug combination (lipid-lowering drugs combined with angiotensin II antagonists and cytokine inhibitors) for the further testing in both preclinical and clinical trials.

Future perspectives of the pharmacological management of diabetic dyslipidemia

INTRODUCTION

Diabetic dyslipidemia is frequent among patients with type 2 diabetes mellitus (T2DM) and is characterized by an increase in triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and small-dense (atherogenic) particles, and by a decrease in low high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (Apo) A1 that are strongly related to insulin resistance. The increased flux of free fatty acids from adipose tissue to the liver aggravates hepatic insulin resistance and promotes all of aspects of the dyslipidemic state. Areas covered: Statins are the first-line agents for treatment while other lipid-lowering drugs (ezetimibe, fibrate and proprotein convertase subtilisin/kexin type 9) or novel anti-diabetic agents (dipeptidyl peptidase-4 inhibitors (DPP-4is), glucagon like peptide-1 receptor agonist (GLP-1RA), sodium/glucose cotransporter 2 inhibitors (SGLT2is)) or nutraceuticals (berberine, omega 3 fatty acid, red yeast rice) can be used alone or in combination. Expert commentary: In patients with T2DM, lipid abnormalities should be identified and treated as part of the overall diabetic treatment, in order to prevent cardiovascular disease. The choice of drugs to be used is mainly based on the lipid profile and on the characteristic lipoprotein abnormalities; the use of new drugs for the treatment of hyperglycemia and lipids alteration in these patients can improve diabetic dyslipidemia.

Improvement of hepatic bioavailability as a new step for the future of statin

Statins (HMG-CoA reductase inhibitors) are a group of highly efficient pharmacological agents used for reducing blood cholesterol level and prevention/treatment of cardiovascular disease. Adverse reactions during statin treatment affect quite significant numbers of patients (reportedly from 5% to 20%), with more side effects occurring at higher doses. Reduced statin dosing can be achieved by improved bioavailability of statins, which is fairly low due to poor aqueous solubility, low permeability and high molecular weight of some members of the statin family. Moreover, since hepatic cholesterologenesis is a main target of statin action and extrahepatic inhibition of HMG-CoA reductase has no effect on plasma lipids, hepatic bioavailability, in our opinion, becomes a new important modality of statins maximizing their potential effect on the plasma lipid profile and diminishing their extrahepatic toxicity. Therefore efficient delivery systems of statins into hepatocytes need to be developed and introduced. Uses of nano-emulsifying statin delivery systems which may include vectors of intrahepatic transport, in particular lycopene, are discussed. As a proof of concept, some preliminary results revealing the effect of a lycopene-containing nanoformulation of simvastatin (designated as Lyco-Simvastatin) on LDL in mildly hypercholesterolemic patients are shown.

Quality and efficiency of statin prescribing across countries with a special focus on South Africa: findings and future implications

INTRODUCTION

Statins are recommended first-line treatment for hyperlipidemia, with published studies suggesting limited differences between them. However, there are reports of under-dosing. South Africa has introduced measures to enhance generic utilization. Part one documents prescribed doses of statins in 2011. Part two determines the extent of generics versus originator and single-sourced statins in 2011 and their costs.

RESULTS

Underdosing of simvastatin in 2011 with average prescribed dose of 23.7 mg; however, not for atorvastatin (20.91 mg) or rosuvastatin (15.02 mg). High utilization of generics versus originators at 93-99% for atorvastatin and simvastatin, with limited utilization of single-sourced statins (22% of total statins - defined daily dose basis), mirroring Netherlands, Sweden and UK. Generics priced 33-51% below originator prices.

DISCUSSION

Opportunity to increase simvastatin dosing through education, prescribing targets and incentives. Opportunity to lower generic prices with generic simvastatin 96-98% below single-sourced prices in some European countries.

Influence of ezetimibe on selected parameters of oxidative stress in rat liver subjected to ischemia/reperfusion

INTRODUCTION

Ischemia/reperfusion (I/R) is considered to be one of the main causes of liver damage after transplantation. The authors evaluated the effect of ezetimibe on selected oxidative stress parameters in ischemic/reperfused (I/R) rat liver.

MATERIAL AND METHODS

Rats were administered ezetimibe (5 mg/kg) (groups E and E-I/R) or saline solution (groups C and C-I/R) intragastrically for 21 days. Livers of animals in groups C-I/R and E-I/R were subjected to 60 min of partial ischemia (left lateral and median lobes) followed by 4 h of reperfusion. Alanine and asparagine aminotransferase (ALT, AST) activity was determined in blood before I/R and during reperfusion (at 15 and 240 min). After the reperfusion period, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx) were determined in liver homogenates using colorimetric methods.

RESULTS

Ezetimibe caused a significant increase in GSH level in groups subjected to I/R (E-I/R (99.91 ±9.01) vs. C-I/R (90.51 ±8.87), p < 0.05). Additionally, under I/R the decrease of GPx activity in the drug-treated group was lower compared to the non-treated group (E-I/R (3.88 ±1.11) vs. E (5.31 ±1.83), p = 0.076). Neither ezetimibe nor I/R affected SOD or MDA levels. I/R produced a significant increase in aminotransferase levels (ALT240-0: C-I/R (42.23 ±43.56) vs. C (9.75 ±11.09), and E-I/R (39.85 ±26.53) vs. E (4.38 ±1.36), p < 0.05 in both cases; AST 240-0: E-I/R (53.87 ±17.23) vs. E (24.10 ±9.66), p < 0.05) but no effect of ezetimibe on those enzymes was found.

CONCLUSIONS

Ezetimibe demonstrates antioxidant properties in rat livers subjected to I/R. However, neither a hepatoprotective nor a hepatotoxic effect of ezetimibe was demonstrated, regardless of I/R.

Differences in metabolic parameters and cardiovascular risk between American Diabetes Association and World Health Organization definition of impaired fasting glucose in European Caucasian subjects: a cross-sectional study

INTRODUCTION

The American Diabetes Association (ADA) defines impaired fasting glucose (IFG) as fasting plasma glucose concentration of 100-125 mg/dl, whereas the World Health Organization (WHO) and the International Diabetes Federation (IDF) define IFG as fasting plasma glucose levels of 110-125 mg/dl. We identified differences in metabolic parameters and cardiovascular disease (CVD) risk according to the ADA or WHO/IDF definition of IFG.

MATERIAL AND METHODS

Healthy drug-naive Caucasian (Greek) subjects (n = 396; age 55 ±12 years) participated in this cross-sectional study.

RESULTS

Diastolic blood pressure (DBP) and uric acid levels were higher in the subjects with glucose 100-109 mg/dl compared with those with glucose < 100 mg/dl (87 ±9 mm Hg vs. 84 ±11 mm Hg, p = 0.004 for DBP, 5.6 ±1.5 mg/dl vs. 5.0 ±1.0 mg/dl, p = 0.002 for uric acid), whereas triglyceride levels were lower in subjects with glucose 100-109 mg/dl compared with those with glucose ≥ 110 mg/dl (169 mg/dl (interquartile range (IQR) = 102-186) vs. 186 mg/dl (IQR = 115-242), p = 0.002). Only the ADA definition recognized subjects with significantly increased 10-year CVD risk estimation (SCORE risk calculation) compared with their respective controls (5.4% (IQR = 0.9-7.3) vs. 4.1% (IQR = 0.7-5.8), p = 0.002).

CONCLUSIONS

The ADA IFG definition recognized more subjects with significantly increased CVD risk (SCORE model) compared with the WHO/IDF definition.

Ginkgo suppresses atherosclerosis through downregulating the expression of connexin 43 in rabbits

INTRODUCTION

Ginkgo biloba extract (GBE) EGb761 is widely used for cardiovascular prevention. Here, we investigated the effects of GBE on atherosclerotic lesion development in rabbits with a high-fat diet.

MATERIAL AND METHODS

Forty New Zealand white male rabbits were randomly divided into four groups. The first two were the normal diet group (C) and the high-fat group (HF). The remaining two groups were those who received a high cholesterol diet supplemented with either the standard drug (simvastatin 2 mg/kg/day) or GBE (3 mg/kg/day). At 12 weeks, histopathological and chemical analyses were performed.

RESULTS

Plasma lipid measurement showed that GBE inhibited high-fat diet-induced increase of serum triglyceride (TG), total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C) by 59.1% (0.9 ±0.2 4 mmol/l vs. 2.2 ±0.4 mmol/l), 18.2% (31.1 ±1.4 mmol/l vs. 38.0 ±0.4 mmol/l) and 15% (28.9 ±1.3 mmol/l vs. 34.0±1.0 mmol/l), respectively, at 12 weeks (p < 0.01). The en face Sudan IV-positive lesion area of the aorta in the GBE group (51.7 ±3.1%) was significantly lower compared with that in the HF group (88.2 ±2.2%; p < 0.01). The mean atherosclerotic lesion area of the GBE group was reduced by 53.2% compared with the HF group (p < 0.01). Immunohistochemistry and western blot analysis showed that GBE markedly suppressed high-fat diet-induced upregulation of connexin 43 (Cx43) in rabbits (p < 0.01).

CONCLUSIONS

Thus, our study revealed that GBE prevented atherosclerosis progress through modulating plasma lipid, suppressing atherosclerotic lesion development, and attenuating the expression of Cx43 protein.

Examination of serum pregnancy-associated plasma protein A clinical value in acute coronary syndrome prediction and monitoring

INTRODUCTION

Chronic vascular inflammatory process promotes and intensifies all atherogenic events. The aim of this research was to estimate the clinical value of pregnancy-associated plasma protein A (PAPP-A) measurement associated with plaque destabilization and rupture in prediction and monitoring of acute coronary syndromes (ACS) as well as to assess the predictive value of this biomarker in comparison to traditional myocardial infarction (MI) risk markers.

MATERIAL AND METHODS

The study included 119 patients in 2 investigated groups and one control group. PAPP-A assay was performed using manual ELISA kit, DRG. All other parameters were determined using automatic analyzers: Olympus and Dade Behring.

RESULTS

A statistically significant difference between PAPP-A concentration median value was found in the investigated group MI individuals' serum and control group individuals' serum (11.42 ng/ml and 7.22 ng/ml respectively, p = 0.003). PAPP-A assay had the highest specificity (83.3%) and sensitivity (53.8%), and therefore the highest clinical value. In patients with clinically and laboratory confirmed MI we proved that PAPP-A serum level is a clinically useful biomarker in ACS prediction, better than C-reactive protein (hsCRP) and fibrinogen (FBG) level.

CONCLUSIONS

The highest diagnostic efficiency for ACS prediction was proved for simultaneous panel assays consisting of 2-3 parameters (PAPP-A - hsCRP, PAPP-A - FBG, PAPP-A - hsCRP - FBG), while PAPP-A itself does not show characteristics necessary for it to be used as a biomarker for MI dynamic monitoring. It is possible that prothrombotic component is mainly responsible for repeated major adverse cardiac events, more than inflammatory process.

Targeted In Situ Gene Correction of Dysfunctional APOE Alleles to Produce Atheroprotective Plasma ApoE3 Protein

Cardiovascular disease is the leading worldwide cause of death. Apolipoprotein E (ApoE) is a 34-kDa circulating glycoprotein, secreted by the liver and macrophages with pleiotropic antiatherogenic functions and hence a candidate to treat hypercholesterolaemia and atherosclerosis. Here, we describe atheroprotective properties of ApoE, though also potential proatherogenic actions, and the prevalence of dysfunctional isoforms, outline conventional gene transfer strategies, and then focus on gene correction therapeutics that can repair defective APOE alleles. In particular, we discuss the possibility and potential benefit of applying in combination two technical advances to repair aberrant APOE genes: (i) an engineered endonuclease to introduce a double-strand break (DSB) in exon 4, which contains the common, but dysfunctional, ε2 and ε4 alleles; (ii) an efficient and selectable template for homologous recombination (HR) repair, namely, an adeno-associated viral (AAV) vector, which harbours wild-type APOE sequence. This technology is applicable ex vivo, for example to target haematopoietic or induced pluripotent stem cells, and also for in vivo hepatic gene targeting. It is to be hoped that such emerging technology will eventually translate to patient therapy to reduce CVD risk.

An attempt to make lipid-lowering therapy more effective in Hungary. The results of MULTI GAP 2010 and the PLUS Program

INTRODUCTION

The primary goal of lipid-lowering therapy is the attainment of low-density lipoprotein cholesterol (LDL-C) target levels.

MATERIAL AND METHODS

The MULTI GAP (MULTI Goal Attainment Problem) 2010 is a part of surveys started a few years ago, in which the lipid results of 1540 patients treated by general practitioners (GPs) and specialists were measured. The data were compared to the results of similar studies involving 15,580 patients between 2004 and 2009.

RESULTS

In 2010 the mean LDL-C level (± SD) of patients treated by GPs was found to be 3.01 ±1.0 mmol/l. The target of 2.50 mmol/l was achieved by 32%, with a mean LDL-C level of 2.84 ±1.0 mmol/l and an achievement rate of 39% in patients treated by specialists. The results of comparisons starting from 2004 showed a marked improvement every year in the beginning, but in the last 3 years stagnation was observed. In 2010 in addition to the MULTI GAP main study, a group of physicians took part in special training called the Plus Program. As a result of this, the LDL-C level was 0.18 mmol/l lower in 114 of the GPs' patients (p = 0.088) and 0.27 mmol/l (p < 0.0001) lower in 313 of the specialists' patients, with a significantly better, 42% (p = 0.045) and 50% (p = 0.001), goal attainment rate, respectively.

CONCLUSIONS

The 2010 MULTI GAP study shows that the quality of lipid-lowering therapy in Hungary seems to be in stagnation. The results of the PLUS Program suggest that continuous training of doctors is the key to further improvement.