Simvastatin-induced changes in circulating oxidized low-density lipoprotein in different types of dyslipidemia

Platelet Redox Imbalance in Hypercholesterolemia: A Big Problem for a Small Cell

The imbalance between reactive oxygen species (ROS) synthesis and their scavenging by anti-oxidant defences is the common soil of many disorders, including hypercholesterolemia. Platelets, the smallest blood cells, are deeply involved in the pathophysiology of occlusive arterial thrombi associated with myocardial infarction and stroke. A great deal of evidence shows that both increased intraplatelet ROS synthesis and impaired ROS neutralization are implicated in the thrombotic process. Hypercholesterolemia is recognized as cause of atherosclerosis, cerebro- and cardiovascular disease, and, closely related to this, is the widespread acceptance that it strongly contributes to platelet hyperreactivity via direct oxidized LDL (oxLDL)-platelet membrane interaction via scavenger receptors such as CD36 and signaling pathways including Src family kinases (SFK), mitogen-activated protein kinases (MAPK), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In turn, activated platelets contribute to oxLDL generation, which ends up propagating platelet activation and thrombus formation through a mechanism mediated by oxidative stress. When evaluating the effect of lipid-lowering therapies on thrombogenesis, a large body of evidence shows that the effects of statins and proprotein convertase subtilisin/kexin type 9 inhibitors are not limited to the reduction of LDL-C but also to the down-regulation of platelet reactivity mainly by mechanisms sensitive to intracellular redox balance. In this review, we will focus on the role of oxidative stress-related mechanisms as a cause of platelet hyperreactivity and the pathophysiological link of the pleiotropism of lipid-lowering agents to the beneficial effects on platelet function.

Decreased Serum Total Bilirubin Level Predicts Early Neurological Deterioration in Patients with Acute Ischemic Stroke

OBJECTIVE

This study aimed to investigate the relationship between serum total bilirubin (TBil) level and early neurological deterioration (END) in patients with acute ischemic stroke of large artery atherosclerosis.

PATIENTS AND METHODS

In this retrospective study, a total of 291 patients with acute ischemic stroke were enrolled. The demographic and laboratory dates were collected. Stroke severity had been assessed using the National Institutes of Health Stroke Scale (NIHSS). Multivariable logistic regression was used to examine the independent association between TBil and END.

RESULTS

Approximately 63 (21.6%) of the patients were diagnosed with END within the first seven days. The proportion of hypertension, diabetes mellitus (DM) and previous stroke/transient ischemic attack (TIA) was significant greater in the lowest quartile (<9.8 μmol/l) of TBil. The proportion of patients with an elevated TBil levels was significantly lower in the END group than in the non-END group. After controlling for covariates, the first quartiles (<9.8 μmol/l) of TBil were still associated with END. In addition, an increased level of CRP and age were also associated with an increased risk of END.

CONCLUSION

The TBil levels in patients with acute cerebral infarction may be a useful biomarker for the prediction of END.

Familial Combined Hyperlipidemia (FCH) Patients with High Triglyceride Levels Present with Worse Lipoprotein Function Than FCH Patients with Isolated Hypercholesterolemia

Lipoprotein characteristics were analyzed in familial combined hyperlipidemia (FCH) patients before and after statin treatment. Twenty-six FCH patients were classified according to the presence (HTG group, n = 13) or absence (normotriglyceridemic (NTG) group, n = 13) of hypertriglyceridemia. Fifteen healthy subjects comprised the control group. Lipid profile, inflammation markers, and qualitative characteristics of lipoproteins were assessed. Both groups of FCH subjects showed high levels of plasma C-reactive protein (CRP), lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and apolipoprotein J. Statins reverted the increased levels of Lp-PLA2 and CRP. Lipoprotein composition alterations detected in FCH subjects were much more frequent in the HTG group, leading to dysfunctional low-density lipoproteins (LDL) and high-density lipoproteins (HDL). In the HTG group, LDL was smaller, more susceptible to oxidation, and contained more electronegative LDL (LDL(-)) compared to the NTG and control groups. Regarding HDL, the HTG group had less Lp-PLA2 activity than the NTG and control groups. HDL from both FCH groups was less anti-inflammatory than HDL from the control group. Statins increased LDL size, decreased LDL(-), and lowered Lp-PLA2 in HDL from HTG. In summary, pro-atherogenic alterations were more frequent and severe in the HTG group. Statins improved some alterations, but many remained unchanged in HTG.

Changes in oxidized lipids drive the improvement in monocyte activation and vascular disease after statin therapy in HIV

BACKGROUND

Oxidative stress plays a significant role in atherosclerosis development. HIV infection has been linked with heightened cardiovascular disease risk. HMG-CoA reductase inhibitors may reduce oxidative stress and subsequently subclinical vascular disease in HIV.

DESIGN/METHODS

This is a randomized, placebo-controlled trial to evaluate the effect of rosuvastatin in HIV-infected adults on stable antiretroviral therapy with low-density lipoprotein less than 130  mg/dl and increased inflammation or T-cell activation on subclinical vascular disease. Changes over 48 weeks in oxidative stress markers, oxidized low-density lipoprotein (oxLDL) and F2-isoprostane/creatinine ratio (F2-IsoP/Cr), were compared between groups. Spearman correlation and multivariable linear regression were used to evaluate relationships between changes in markers of oxidative stress, inflammation and monocyte activation and carotid intima media thickness (CIMT).

RESULTS

One hundred and forty-seven adults enrolled (72 to rosuvastatin and 75 to placebo). In the rosuvastatin group, oxLDL decreased significantly over 24 weeks compared to placebo [mean absolute change in log-oxLDL for rosuvastatin -0.2  ±  0.468 log U/l (P < 0.001 within-group) vs. placebo -0.018  ±  0.456 log U/l (P = 0.83 within-group); P = 0.004 between groups] and this change was linked with changes in soluble CD14 and proportion of patrolling monocytes (CD14dimCD16). Although oxLDL levels increased after initially declining and were not different from placebo at week 48, the early improvement in oxLDL was associated with improved CIMT at week 48. Changes in F2-IsoP/Cr were not significant between groups.

CONCLUSION

Rosuvastatin decreases oxLDL levels early after initiation and is associated with decreased monocyte activation. Early improvement in oxLDL is linked with improved CIMT in treated HIV infection.

The good and bad effects of statins on insulin sensitivity and secretion

AIMS

Statins are the main lipid-lowering treatment in both primary and secondary prevention populations. Whether statins deteriorates glycemic control, predisposing to the onset of diabetes mellitus has been a matter of recent concern. Statins may accelerate progression to diabetes via molecular mechanisms that impact insulin sensitivity and secretion. In this review, we debate the relative effect of statins in driving insulin resistance and the impairment of insulin secretion.

METHODS

Narrative overview of the literature synthesizing the findings of literature was retrieved from searches of computerized databases, hand searches, and authoritative texts employing the key words "Statins", "Randomized Clinical Trial", "Insulin sensitivity", "Insulin resistance", "Insulin Secretion", "Diabetes Mellitus" alone and/or in combination.

RESULTS

The weight of clinical evidence suggests a worsening effect of statins on insulin resistance and secretion, anyway basic science studies did not find a clear molecular explanation, providing conflicting evidence regarding both the beneficial and the adverse effects of statin therapy on insulin sensitivity.

CONCLUSIONS

Although most of the clinical studies suggest a worsening of insulin resistance and secretion, the cardiovascular benefits of statin therapy outweigh the risk of developing insulin resistance, thus the data suggest the need to treat dyslipidemia and to make patients aware of the possible risk of developing type 2 diabetes or, if they already are diabetic, of worsening their metabolic control.

Changes in serum cholesterol levels determine future risk of cardiovascular events in patients with acute coronary syndrome in the Japanese Coronary Artery Disease (JCAD) Study

BACKGROUND

Although increased attention is given to assess absolute values of serum cholesterol profiles as optimal markers for preventing future cardiovascular (CV) events, changes in cholesterol profiles also have the potential to be associated with CV disease outcome in Japanese patients with acute coronary syndrome (ACS).

METHODS

From the database of the Japanese Coronary Artery Disease (JCAD) study, 2664 patients with ACS who had serial measurements of serum cholesterol profile parameters were enrolled. These patients were followed-up for a mean period of 2.7 years. The endpoint was all CV events. Baseline clinical characteristics of patients with and without CV events were adjusted by the propensity score matching analysis.

RESULTS

None of the serum absolute cholesterol profiles at baseline and 6 months later was associated with CV events, except for baseline serum total cholesterol level. However, large improvements in cholesterol profiles correlated with better CV disease outcome.

CONCLUSIONS

This subanalysis of JCAD demonstrated the importance of serial assessment of serum cholesterol profiles for secondary prevention of CV events in Japanese patients with ACS. Changes in serum cholesterol profiles, rather than their absolute values, correlated with future CV events.

AFM investigation on Ox-LDL-induced changes in cell spreading and cell-surface adhesion property of endothelial cells

The integrity and adhesion properties of endothelium play vital roles during atherosclerosis. It is well known that oxidized low-density lipoprotein (Ox-LDL) influences many physiological activities or mechanical properties of endothelial cells. However, the effects of Ox-LDL on the integrity and nonspecific adhesion properties of endothelial cells are still unclear. In this study, using the topographical imaging and force measurement functions of atomic force microscopy (AFM), we found that Ox-LDL can transiently weaken the integrity of endothelium by impairing cell spreading of endothelial cells and decrease the attachment of irrelevant blood cells to endothelium by impairing the nonspecific adhesion property of endothelial cells. The AFM-based data provide important information for understanding the effects of Ox-LDL on endothelial cells or during atherogenesis.

Antiaging effects of simvastatin on vascular endothelial cells

The anti-inflammatory, antioxidative, and antiarteriosclerosis activities of simvastatin along with its protective effects on the endothelium suggest that it may also have antiaging effects. The aim of this study was to investigate the antiaging effects of simvastatin as well as its effects on sirtuin 1 (SIRT1) expression in endothelial cells. Aged rats and human umbilical vein endothelial cells were treated with simvastatin in the presence and absence of oxidized low-density lipoprotein (OX-LDL). Aortic β-galactosidase staining was undertaken to determine senescence, and SIRT1 protein expression was evaluated using Western blot analysis. After simvastatin therapy, arterial endothelial cell aging was significantly reduced, and SIRT1 expression was significantly increased. The OX-LDL significantly accelerated the senescence of umbilical vein endothelial cells and decreased SIRT1 expression. The OX-LDL-induced downregulation of SIRT1 was blocked by simvastatin. Simvastatin treatment also reduced umbilical vein endothelial cell aging and increased SIRT1 expression.

Oxidized lipoprotein(a) and cardio-ankle vascular index (CAVI) in hypertensive subjects

While oxidized lipoprotein(a) (oxLp(a)) has been indicated to be involved in atherogenesis more than native lipoprotein(a) (Lp(a)), there is still a need to elucidate the associations among oxLp(a), hypertension, and atherosclerosis. The cardio-ankle vascular index (CAVI) is a recently developed index used to assess arterial stiffness that is independent of blood pressure components. The present study investigated the correlation between oxLp(a) and the CAVI among hypertensive subjects. Clinical data, including general atherosclerotic risk factors, in addition to Lp(a), oxLp(a), and the CAVI, were collected from 72 non-smoking, asymptomatic, and untreated female subjects (mean age: 64.3 years). Correlations between the CAVI and Lp(a) or oxLp(a) were examined in a hypertensive group (n = 34) and a non-hypertensive control group (n = 38). There was a significant and positive correlation between the CAVI and subject age in the control group, while there was a significant and positive correlation between the CAVI and subject age, systolic blood pressure, and oxLp(a) (r = 0.38, p < 0.05) in the hypertensive group. A stepwise multiple linear regression analysis identified the oxLp(a) to be correlated independently, significantly, and positively with the CAVI (β = 0.30, p < 0.05) in the hypertensive group, while this correlation was not significant in the control group. These findings suggest that the oxidative modification of Lp(a) may be associated with arterial stiffness in hypertensive, but not non-hypertensive, female subjects.

Effects of lipid-lowering therapy with strong statin on serum polyunsaturated fatty acid levels in patients with coronary artery disease

Residual risk of cardiovascular events after treatment with stain might be explained in part because patients have low levels of n-3 polyunsaturated fatty acids (PUFA). We examined how lipid-lowering therapy with strong statin affected serum PUFA levels in patients with coronary artery disease. The study population consisted of 46 patients with coronary artery disease whose low-density lipoprotein (LDL) cholesterol was more than 100 mg/dl. Lipid-lowering therapy was performed with a strong statin including atorvastatin (n = 22), rosuvastatin (n = 9) or pitavastatin (n = 15). Serum PUFA levels were determined by gas chromatography. The treatment with strong statin decreased the sum of dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA) levels (195 ± 41 to 184 ± 44 μg/ml, P < 0.05) as well as the sum of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels (233 ± 71 to 200 ± 72 μg/ml, P < 0.001). These effects of strong statin resulted in a significant decrease in ratio of the sum of EPA and DHA levels to the sum of DGLA and AA levels (1.20 ± 0.27 to 1.10 ± 0.35, P < 0.05). The percent decrease in the LDL cholesterol level correlated significantly with that in the sum of EPA and DHA levels (r = 0.38, P < 0.01). In conclusion, our results showed that lipid-lowering therapy with strong statin mainly reduced n-3 PUFAs in proportion to the decrease in the LDL cholesterol level in patients with coronary artery disease.

Negatively charged low-density lipoprotein is associated with atherogenic risk in hypertensive patients

Negatively charged low-density lipoprotein (LDL), generated via multiple processes such as oxidation, acetylation, or glycosylation, plays a key role in the initiation and progression of atherosclerosis and related diseases. Anion-exchange high-performance liquid chromatography (AE-HPLC) can subfractionate LDL into LDL-1, LDL-2, and LDL-3 based on LDL particle charge, but the clinical significance of LDL subfractions has not yet been elucidated. The aim of this study was to determine the clinical significance of these fractions with particular regard to atherogenic risk in hypertensive patients. Ninety-eight patients with essential hypertension (age 67.0 ± 10.7 years; 54 males) were enrolled in the present study. The relationships between LDL subfractions and atherogenic risk factors, including lipid profiles, blood pressure and plasma 8-isoprostane as a marker of oxidative stress, were examined. LDL-1 levels were significantly and negatively correlated with body mass index (r = -0.384, p < 0.001), systolic blood pressure (r = -0.457, p < 0.001), non-high-density lipoprotein cholesterol levels (r = -0.457, p < 0.001) and 8-isoprostane levels (r = -0.415, p < 0.001). LDL-3, which is the most negatively charged fraction of total LDL, was significantly and positively correlated with these parameters (r = 0.267, 0.481, 0.357, and 0.337, respectively). LDL-1 levels were significantly lower (p < 0.001), and LDL-2 and LDL-3 levels were significantly higher (each p < 0.001) in patients with poorly controlled hypertension than in patients with well-controlled hypertension. In addition, an increase in the total number of traditional risk factors at time of study participation, but not previous diagnosis, was associated with a decrease in LDL-1 levels and increases in LDL-2 and LDL-3 levels. These data suggest that LDL subfractions are associated with multiple atherogenic risk factors and that treatment to modify these risk factors could result in changes in LDL subfraction levels. In conclusion, LDL subfractions isolated by AE-HPLC may represent a marker of atherogenic risk in patients with hypertension.

Relationship between cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC) in patients with type 2 diabetes mellitus

Early detection of atherosclerosis is important for patients with type 2 diabetes mellitus because cardiovascular disease (CVD) is a main cause of death in these people. In this study, we investigated the relationship between an arterial stiffness parameter called cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC). We performed a cross-sectional study in 371 type 2 diabetic patients with clinical suspicion of coronary heart disease (CHD). We evaluated the relationships between CAVI and CAC score determined by multislice computed tomography as well as major cardiovascular risk factors, including age, body mass index, hemoglobinA1c and the Framingham CHD risk score. CAVI was correlated with age (r = 0.301, p < 0.0001), uric acid (r = 0.236, p < 0.0001), estimated glomerular filtration rate (r = -0.145, p = 0.0166), CHD risk score (r = 0.327, p < 0.0001) and log (CAC + 1) (r = 0.303, p < 0.0001). The area under the receiver operating characteristic curve for CAVI was higher than that of CHD risk score in predicting CAC >0, CAC >100, CAC >400, or CAC >1000. CAVI is positively correlated with CAC, and is considered to be a useful method to detect CAC.

Uncontrolled home blood pressure in the morning is associated with nephropathy in Japanese type 2 diabetes

The purposes of this study were to investigate the state of blood pressure control level and to investigate the relationship between blood pressure control level and nephropathy in Japanese type 2 diabetes. We measured clinic and home blood pressure in 923 type 2 diabetic patients. According to the criteria for hypertension in the Japanese Society of Hypertension Guidelines 2009, patients were classified into four groups by clinic systolic blood pressure (130 mmHg) and morning systolic blood pressure (125 mmHg), as follows: controlled hypertension (CH), white-coat hypertension (WCH), masked hypertension (MH), and sustained hypertension (SH). Of all patients, 13.9, 12.6, 13.3, and 60.2% were identified as having CH, WCH, MH, and SH, respectively. The average number of drugs prescribed was 1.8. We assessed the association between blood pressure control level and nephropathy in diabetic patients. The degree of urinary albumin excretion and the prevalence of nephropathy in diabetic patients were higher in MH and SH groups than those in the CH group. The majority of patients had poor blood pressure control, regardless of ongoing conventional antihypertensive therapy, and diabetic patients with MH and SH were associated with nephropathy. It is suggested that more aggressive antihypertensive treatment is recommended to prevent nephropathy in diabetic patients.