Selenoproteins, Cholesterol-Lowering Drugs, and the Consequences Revisiting of the Mevalonate Pathway
ABSTRACT 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and peroxisome proliferator-activated receptor alpha activators (fibrates) are the backbone of pharmacologic hypercholesterolemia and dyslipidemia treatment. Many of their clinical effects, however, are still enigmatic. This article describes how a side road of the mevalonate pathway, characterized in recent years, can rationalize a major fraction of these unexplained observations. This side road is the enzymatic isopentenylation of selenocysteine-tRNA([Ser]Sec) (Sec-tRNA), the singular tRNA to decode the unusual amino acid selenocysteine. The functionally indispensable isopentenylation of Sec-tRNA requires a unique intermediate from the mevalonate pathway, isopentenyl pyrophosphate, which concomitantly constitutes the central building block for cholesterol biosynthesis, and whose formation is suppressed by statins and fibrates. The resultant inhibition of Sec-tRNA isopentenylation profoundly decreases selenoprotein expression. This effect might seamlessly explain the immunosuppressive, redox, endothelial, sympatholytic, and thyroidal effects of statins and fibrates as well as their common side effects and drug interactions.
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- "A combined therapeutic approach with selenium and CoQ10 could constitute an exciting area for future research, because such a combination could probably be useful for the treatment of statin-associated myopathy. In contrast, selenium supplementation in atherosclerosis seems to be contraindicated, owing to possible atherogenic influences (Nordman et al 2003; Moosmann and Behl 2004b). "
ABSTRACT: The objective of this study was to evaluate the possible benefits of coenzyme Q and selenium supplementation administered to patients with statin-associated myopathy (SAM). Sixty eligible patients entered the pilot study. Laboratory examination (CoQ10, selenium, creatin kinase) and intensity of SAM (visual scale) were performed at baseline, after 1 month, and at the end of study at month 3. Plasma levels of CoQ10 increased from 0.81 ± 0.39 to 3.31 ± 1.72 μmol/L in the active group of patients treated by CoQ10, compared with the placebo (p = 0.001). Also, the symptoms of SAM significantly improved in the active group (p < 0.001): the intensity of muscle pain decreased from 6.7 ± 1.72 to 3.2 ± 2.1 (p < 0.01, -53.4 ± 28.2%); muscle weakness decreased from 7.0 ± 1.63 to 2.8 ± 2.34 (p < 0.01, -60 ± 24.0%); muscle cramps decreased from 5.33 ± 2.06 to 1.86 ± 2.42, p < 0.01, -65 ± 28%); tiredness decreased from the initial 6.7 ± 1.34 to 1.2 ± 1.32 (p < 0.01, -82 ± 22%). We did not observe any significant changes in the placebo group. In conclusion, supplementation of statin-treated patients with CoQ10 resulted in a decrease in the symptoms of SAM, both in absolute numbers and intensity. Additional selenium supplementation was not associated with any statistically significant decrease of SAM. However, it is not possible to draw any definite conclusions, even though this study was carried out in double-blind fashion, because it involved a small number of patients.Canadian Journal of Physiology and Pharmacology 02/2013; 91(2):165-70. DOI:10.1139/cjpp-2012-0118 · 1.55 Impact Factor
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ABSTRACT: The public perception of selenium has changed significantly over the last decades. Originally mainly known for its high toxicity, it was later recognized as an essential trace element and is now (despite its narrow therapeutic window) almost being marketed as a lifestyle drug. Indeed, some clinical and preclinical studies suggest that selenium supplementation may be beneficial in a large number of clinical conditions. However, its mode of action is unresolved in most of these cases. Selenocysteine - identified as the 21st amino acid used in ribosome-mediated protein synthesis - is incorporated in at least 25 specific, genetically determined human selenoproteins, many of which have only recently been discovered. Restoration of normal selenoprotein levels may be - apart from direct supranutritional effects - one possible explanation for the effects of selenium supplements. In this review we provide a brief but up-to-date overview of what is currently known about these 25 acknowledged human selenoproteins and their synthesis.Cellular and Molecular Life Sciences CMLS 12/2005; 62(21):2414-37. DOI:10.1007/s00018-005-5143-y · 5.86 Impact Factor