Hannu Päivä

Risk of acute coronary events and serum concentration of asymmetrical dimethylarginine

Asymmetrical dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor, which has been suggested to be a novel independent risk factor for endothelial dysfunction and coronary heart disease. We investigated the association of ADMA concentration in serum with risk of acute coronary events. We did a prospective, nested, case-control study in middle-aged men from eastern Finland. In an analysis of men who did not smoke, those who were in the highest quartile for ADMA (>0.62 micromol/L) had a 3.9-fold (95% CI 1.25-12.3, p=0.02) increase in risk of acute coronary events compared with the other quartiles. Our findings suggest that ADMA is a predictor of acute coronary events.

High-dose statins and skeletal muscle metabolism in humans: A randomized, controlled trial

Myopathy, probably caused by 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase inhibition in skeletal muscle, rarely occurs in patients taking statins. This study was designed to assess the effect of high‐dose statin treatment on cholesterol and ubiquinone metabolism and mitochondrial function in human skeletal muscle.

A Systems Biology Strategy Reveals Biological Pathways and Plasma Biomarker Candidates for Potentially Toxic Statin-Induced Changes in Muscle

Background Aggressive lipid lowering with high doses of statins increases the risk of statin-induced myopathy. However, the cellular mechanisms leading to muscle damage are not known and sensitive biomarkers are needed to identify patients at risk of developing statin-induced serious side effects. Methodology We performed bioinformatics analysis of whole genome expression profiling of muscle specimens and UPLC/MS based lipidomics analyses of plasma samples obtained in an earlier randomized trial from patients either on high dose simvastatin (80 mg), atorvastatin (40 mg), or placebo. Principal Findings High dose simvastatin treatment resulted in 111 differentially expressed genes (1.5-fold change and p-value<0.05), while expression of only one and five genes was altered in the placebo and atorvastatin groups, respectively. The Gene Set Enrichment Analysis identified several affected pathways (23 gene lists with False Discovery Rate q-value<0.1) in muscle following high dose simvastatin, including eicosanoid synthesis and Phospholipase C pathways. Using lipidomic analysis we identified previously uncharacterized drug-specific changes in the plasma lipid profile despite similar statin-induced changes in plasma LDL-cholesterol. We also found that the plasma lipidomic changes following simvastatin treatment correlate with the muscle expression of the arachidonate 5-lipoxygenase-activating protein. Conclusions High dose simvastatin affects multiple metabolic and signaling pathways in skeletal muscle, including the pro-inflammatory pathways. Thus, our results demonstrate that clinically used high statin dosages may lead to unexpected metabolic effects in non-hepatic tissues. The lipidomic profiles may serve as highly sensitive biomarkers of statin-induced metabolic alterations in muscle and may thus allow us to identify patients who should be treated with a lower dose to prevent a possible toxicity.

Decreased Skeletal Muscle Mitochondrial DNA in Patients Treated with High-Dose Simvastatin

Statins are generally well tolerated, but can cause myopathy 1 and have been associated with mitochondrial abnormalities. 2, 3, 4, 5, 6 The aim of this study was to determine whether muscle mitochondrial DNA (mtDNA) levels are altered during statin therapy. We retrospectively quantified mtDNA in 86 skeletal muscle biopsy specimens collected as part of a previously published 7 clinical trial of high‐dose simvastatin or atorvastatin versus placebo.

Effect of high-dose statin treatment on plasma concentrations of endogenous nitric oxide synthase inhibitors.

Asymmetric dimethylarginine (ADMA) and monomethylarginine (LMMA) are endogenous inhibitors of nitric oxide synthase. A high level of ADMA in plasma has shown to be a significant risk factor for acute coronary syndromes and elevated plasma ADMA levels are prevalent in patients with hypercholesterolemia. It was therefore hypothesized that lowering plasma cholesterol levels with statin treatment would also lower ADMA concentrations. This double-blind study addressed the effect of high-dose statin treatment on plasma levels of ADMA and LMMA. Forty-eight subjects with mild hypercholesterolemia were randomly assigned to receive simvastatin 80 mg/d, atorvastatin 40 mg/d, or placebo for 8 weeks. Both statins decreased low-density lipoprotein cholesterol effectively (simvastatin 54% and atorvastatin 49%). However, concentrations of arginine derivatives remained unchanged during statin treatment and did not correlate with cholesterol levels. This study indicates that statin treatment has no clear influence on plasma ADMA or LMMA concentrations.

Asymmetrical dimethylarginine (ADMA) and risk of acute coronary events: Does statin treatment influence plasma ADMA levels?

The purpose of this study was to evaluate the hypothesis that high serum levels of ADMA, an indicator of endothelial dysfunction, are associated with an elevated risk of acute coronary events in middle-aged men. To test the hypothesis that lipid lowering medication with statins lowers circulating ADMA levels, we also investigated the effect of simvastatin and atorvastatin treatment on plasma ADMA concentration. In a prospective nested case-control study in 150 middle-aged non-smoking men from Eastern Finland, those who were in the highest quartile for serum ADMA (>0.62 micromol/l) had a 3.9-fold (95% CI: 1.25-12.3, P=0.02) increase in risk of acute coronary events compared with other quartiles. In an 8-week randomised double-blind placebo-controlled trial, plasma ADMA concentrations remained unchanged in simvastatin 80 mg/day (n=16), atorvastatin 40 mg/day (n=16) and placebo (n=16) groups over the study period. Our findings indicate that high serum levels of ADMA, a potential marker for endothelial dysfunction, may increase the risk of acute coronary syndromes. However, aggressive treatment with either simvastatin or atorvastatin did not reduce plasma ADMA levels.

Plasma Asymmetric Dimethylarginine and Hyperemic Myocardial Blood Flow in Young Subjects With Borderline Hypertension or Familial Hypercholesterolemia

OBJECTIVE The goal of this study was to examine the relationship between plasma asymmetric dimethylarginine (ADMA) level and hyperemic myocardial blood flow (MBF) in subjects with borderline hypertension (BHT) and familial hypercholesterolemia (FH). METHODS Asymmetric dimethylarginine is an endogenous competitive inhibitor of nitric oxide synthase that may modulate vascular function. We measured plasma ADMA levels and myocardial flow in 77 young men (mean age 35 +/- 5 years), including 47 healthy controls, 16 men with BHT, and 14 men with FH. Basal and dipyridamole-induced myocardial flow was measured using positron emission tomography. Plasma ADMA levels were measured using high-pressure liquid chromatography. RESULTS Asymmetric dimethylarginine levels were significantly elevated in the BHT group compared with controls (0.59 +/- 0.13 micromol/l vs. 0.43 +/- 0.12 micromol/l, p < 0.001), and they had significantly lower dipyridamole flow (2.85 +/- 1.20 ml/min/g vs. 3.69 +/- 1.68 ml/min/g, p < 0.05). In a multivariate regression model adjusted for the study group, dipyridamole flow was inversely associated with ADMA (p < 0.05), age (p < 0.05), and apolipoprotein B concentration (p < 0.05). CONCLUSIONS We conclude that plasma ADMA concentration is related to dipyridamole-induced vasodilatory function in young men, independently of blood pressure elevation and hypercholesterolemia. Subjects with BHT have significantly increased plasma ADMA levels, which may partly explain the impaired hyperemic MBF in this condition.

High‐Dose Statin Treatment Does Not Alter Plasma Marker for Brain Cholesterol Metabolism in Patients With Moderately Elevated Plasma Cholesterol Levels

Statins inhibit endogenous cholesterol synthesis, up‐regulate low‐density lipoprotein (LDL) receptor expression in mammalian liver cells, and thus decrease circulating LDL‐cholesterol concentrations. As cholesterol seems to play a role in the development of neurodegenerative diseases, it is of interest to evaluate the effect of high dosages of statins (eg, atorvastatin or simvastatin) on brain cholesterol metabolism. Plasma samples from 44 participants (aged 30–69 years, 16 men and 18 women) of an earlier randomized, placebo‐controlled, double‐blind trial, who took 40 mg atorvastatin or 80 mg simvastatin daily for 2 months, were used to analyze total cholesterol, its precursor lathosterol, and its metabolites 24(S)‐hydroxycholesterol and 27‐hydroxycholesterol. Despite a significant decrease in absolute plasma concentrations of oxysterols, total cholesterol, and its endogenous synthesis rate, indicated by a decreased ratio of lathosterol to cholesterol, the plasma 24(S)‐hydroxycholesterol to cholesterol ratio, a surrogate marker of brain cholesterol homeostasis, remained unchanged. Short‐term high‐dose atorvastatin and simvastatin treatment does not seem to influence brain cholesterol metabolism in patients with moderately elevated plasma cholesterol levels.

Levels of asymmetrical dimethylarginine are predictive of brachial artery flow-mediated dilation 6 years later. The Cardiovascular Risk in Young Finns Study

AIM Plasma asymmetric dimethylarginine (ADMA) is a novel risk factor for atherosclerosis and has been observed to associate with endothelial function in cross-section studies. In the present study our aim was to investigate whether plasma ADMA levels are predictive of brachial artery endothelial function in a prospective setting. METHODS AND RESULTS Using ultrasound we measured brachial artery flow-mediated dilation (FMD) both in 2001 and 2007 in 1808 healthy subjects aged 24-39 years at baseline. Plasma methylarginines were determined by isocratic high-pressure liquid chromatography in 2001. In a multivariable model adjusted with brachial diameter and conventional cardiovascular risk factors, baseline ADMA levels had a significant inverse association with FMD measured 6 years later (β±SE: -1.89±0.69%, P=0.006). CONCLUSIONS We conclude that plasma ADMA can predict brachial artery FMD in subjects without prevalent atherosclerotic disease. These data suggest that plasma ADMA may have a determinative role in predicting endothelial function.

Beyond LDL-C lowering: Distinct molecular sphingolipids are good indicators of proprotein convertase subtilisin/kexin type 9 (PCSK9) deficiency

OBJECTIVES Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) has been proposed to be a potential new therapeutic target for treatment of hypercholesterolaemia. However, little is known about the effects of PCSK9 inhibition on the lipidome. METHODS We performed molecular lipidomic analyses of plasma samples obtained from PCSK9-deficient mice, and serum of human carriers of a loss-of-function variant in the PCSK9 gene (R46L). RESULTS In both mouse and man, PCSK9 deficiency caused a decrease in several cholesteryl esters (CE) and short fatty acid chain containing sphingolipid species such as CE 16:0, glucosyl/galactosylceramide (Glc/GalCer) d18:1/16:0, and lactosylceramide (LacCer) d18:1/16:0. In mice, the changes in lipid concentrations were most prominent when animals were given regular chow diet. In man, a number of molecular lipid species was shown to decrease significantly even when LDL-cholesterol was non-significantly reduced by 10% only. Western diet attenuated the lipid lowering potency of PCSK9 deficiency in mice. CONCLUSIONS Plasma molecular lipid species may be utilized for characterizing novel compounds inhibiting PCSK9 and as sensitive efficacy markers of the PCSK9 inhibition.