Reijo Laaksonen

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.

miR-21, miR-210, miR-34a, and miR-146a/b are up-regulated in human atherosclerotic plaques in the Tampere Vascular Study

OBJECTIVE MicroRNAs are small non-coding RNAs that inversely regulate their target gene expression. The whole miRNA profile of human atherosclerotic plaques has not been studied previously. The aim of this study was to investigate the miRNA expression profile in human atherosclerotic plaques as compared to non-atherosclerotic left internal thoracic arteries (LITA), and to connect this expression to the processes in atherosclerosis. METHODS The miRNA expression profiles of six LITAs and 12 atherosclerotic plaques obtained from aortic, carotid, and femoral atherosclerotic arteries from Tampere Vascular Study were analyzed. The analyses were performed with Agilents miRNA Microarray. The expression levels of over 4-fold up-regulated miRNAs were verified with qRT-PCR from a larger population (n=50). Messenger RNA levels were analyzed with Illuminas Expression BeadChip to study miRNA target expression. RESULTS Ten miRNAs were found to be differently expressed in atherosclerotic plaques when compared to controls (p<0.05). The expression of miR-21, -34a, -146a, -146b-5p, and -210 was verified and found to be significantly up-regulated in atherosclerotic arteries versus LITAs (p<0.001, fold changes 4.61, 2.55, 2.87, 2.82, and 3.92, respectively). Several predicted targets of these miRNAs were down-regulated, and gene set enrichment analysis showed several pathways which could be differently expressed due to this miRNA profile. CONCLUSIONS The microRNA expression profile differs significantly between atherosclerotic plaques and control arteries. The most up-regulated miRNAs are involved in processes known to be connected to atherosclerosis. Interfering with the miRNA expression in the artery wall is a potential way to affect atherosclerotic plaque and cardiovascular disease development.

Low-density lipoprotein-independent effects of statins.

Statins have pleiotropic properties that complement their cholesterol-lowering effects. These properties may partly account for their established benefit in the prevention of coronary artery disease beyond the reduction of LDL-cholesterol levels. The most widely recognized properties are reviewed here. They include: (i) nitric oxide-mediated improvement of endothelial dysfunction and upregulation of endothelin-1 expression; (ii) antioxidant effects; (iii) anti-inflammatory properties; (iv) inhibition of cell proliferation with anticarcinogenic actions in animals; (v) stabilization of atherosclerotic plaques; (vi) anticoagulant effects; and (vii) inhibition of graft rejection after heart and kidney transplantation. As advances are made in our knowledge, new properties are steadily being uncovered. Pleiotropic effects are currently being given consideration when instituting combination therapy for patients at high cardiovascular risk. Some pleiotropic effects are negative, and may account for occasional untoward drug interactions. For many of these new properties, the clinical relevance has not been established. The challenge for the future will be to design and carry out appropriate clinical trials to establish their relative importance in the prevention of coronary artery disease.

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.

The effect of Simvastatin treatment on natural antioxidants in low-density lipoproteins and high-energy phosphates and ubiquinone in skeletal muscle*

It has been hypothesized that treating hypercholesterolemic patients with statins will lead not only to a reduction in cholesterol, but also to inhibited synthesis of other compounds which derive from the synthetic pathway of cholesterol. In theory, this could further lead to ubiquinone deficiency in muscle cell mitochondria, disturbing normal cellular respiration and causing adverse effects such as rhabdomyolysis. Furthermore, ubiquinone is one of the lipophilic antioxidants in low-density lipoprotein (LDL), and therefore it has also been hypothesized that statin treatment will reduce the antioxidant capacity of LDL. We investigated the effect of 6 months of simvastatin treatment (20 mg/day) on skeletal muscle concentrations of high-energy phosphates and ubiquinone by performing biopsies in 19 hypercholesterolemic patients. Parallel assays were performed in untreated control subjects. The muscle high-energy phosphate and ubiquinone concentrations assayed after simvastatin treatment were similar to those observed at baseline and did not differ from the values obtained in control subjects at the beginning and end of follow-up. These results do not support the hypothesis of diminished isoprenoid synthesis or energy generation in muscle cells during simvastatin treatment. Furthermore, the results of analysis of antioxidant concentrations in LDL before and after simvastatin treatment indicate that the antioxidant capacity of LDL is maintained in simvastatin-treated patients.

Decreases in serum ubiquinone concentrations do not result in reduced levels in muscle tissue during short-term simvastatin treatment in humans

Statins, which are commonly used drugs for hypercholesterolemia, inhibit 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, the rate‐limiting enzyme in cholesterol synthesis. Important nonsterol compounds, such as ubiquinone, are also derived from the same synthetic pathway. Therefore it has been hypothesized that statin treatment causes ubiquinone deficiency in muscle cells, which could interfere with cellular respiration causing severe adverse effects. In this study we observed decreased serum levels but an enhancement in muscle tissue ubiquinone levels in patients with hypercholesterolemia after 4 weeks of simvastatin treatment. These results indicate that ubiquinone supply is not reduced during short‐term statin treatment in the muscle tissue of subjects in whom myopathy did not develop.

Design of the Coronary ARtery DIsease Genome-Wide Replication And Meta-Analysis (CARDIoGRAM) Study: A Genome-Wide Association Meta-analysis Involving More Than 22 000 Cases and 60 000 Controls

Background—Recent genome-wide association studies (GWAS) of myocardial infarction (MI) and other forms of coronary artery disease (CAD) have led to the discovery of at least 13 genetic loci. In addition to the effect size, power to detect associations is largely driven by sample size. Therefore, to maximize the chance of finding novel susceptibility loci for CAD and MI, the Coronary ARtery DIsease Genome-wide Replication And Meta-analysis (CARDIoGRAM) consortium was formed. Methods and Results—CARDIoGRAM combines data from all published and several unpublished GWAS in individuals with European ancestry; includes >22 000 cases with CAD, MI, or both and >60 000 controls; and unifies samples from the Atherosclerotic Disease VAscular functioN and genetiC Epidemiology study, CADomics, Cohorts for Heart and Aging Research in Genomic Epidemiology, deCODE, the German Myocardial Infarction Family Studies I, II, and III, Ludwigshafen Risk and Cardiovascular Heath Study/AtheroRemo, MedStar, Myocardial Infarction Genetics Consortium, Ottawa Heart Genomics Study, PennCath, and the Wellcome Trust Case Control Consortium. Genotyping was carried out on Affymetrix or Illumina platforms followed by imputation of genotypes in most studies. On average, 2.2 million single nucleotide polymorphisms were generated per study. The results from each study are combined using meta-analysis. As proof of principle, we meta-analyzed risk variants at 9p21 and found that rs1333049 confers a 29% increase in risk for MI per copy (P=2×10−20). Conclusion—CARDIoGRAM is poised to contribute to our understanding of the role of common genetic variation on risk for CAD and MI.

Serum ubiquinone concentrations after short- and long-term treatment with HMG-CoA reductase inhibitors.

Serum ubiquinone levels were studied during long- and short-term treatment with 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors in 17 men with primary non-familial hypercholesterolaemia. The serum ubiquinone levels were determined after the patients had received simvastatin (20–40 mg per day) for 4.7 years, after a 4 week treatment pause and again after they had resumed treatment with lovastatin (20–40 mg per day) for 12 weeks.During the treatment pause the average serum ubiquinone levels increased by 32%; resumption of treatment caused a reduction of 25%. The changes in the levels of ubiquinone and serum total cholesterol as well as those of ubiquinone and low-density lipoprotein cholesterol were closely parallel.This suggested that changes in serum ubiquinone reflected changes in cholesterol-containing serum lipoproteins which could serve as carrier vehicles for ubiquinone. After long-term simvastain treatment and after short-term lovastatin treatment, average serum ubiquinone levels (1.16 and 1.22 mg·l-1, respectively) were similar to that observed in a group of apparently healthy middle-aged men (1.16 mg·l-1).

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.