A comparison of the effects of lovastatin and pravastatin on ubiquinone tissue levels in rats

CoQ10 a super-vitamin: review on application and biosynthesis

Coenzyme Q10 (CoQ) or ubiquinone is found in the biological system which is synthesized by the conjugation of benzoquinone ring with isoprenoid chain of variable length. Coenzyme Q10 supplementation energizes the body and increases body energy production in the form of ATP and helps to treat various human diseases such as cardiomyopathy, muscular dystrophy, periodontal disease, etc. Reports of these potential therapeutic advantages of CoQ10 have resulted in its high market demand, which focus the researchers to work on this molecule and develop better bioprocess methods for commercial level production. At the moment, chemical synthesis, semi-synthetic method as well as bio-production utilizing microbes as biofactory are in use for the synthesis of CoQ10. Chemical synthesis involves use of cheap and easily available precursor molecules such as isoprenol, chloromethylquinone, vinylalane, and solanesol. Chemical synthesis methods due to the use of various solvents and chemicals are less feasible, which limits its application. The microbial production of CoQ10 has added advantages of being produced in optically pure form with high yield using inexpensive medium composition. Several bacteria, e.g., Agrobacterium, Paracoccus, Rhodobacterium, and yeast such as Candida, Rhodotorula are the potent ubiquinone producer. Some alternative biosynthetic pathway for designing of CoQ10 production coupled with metabolic engineering might help to increase CoQ10 production. The most common practiced strategy for strain development for commercial CoQ10 production is through natural isolation and chemical mutagenesis. Here, we have reviewed the chemical, semi-synthetic as well as microbial CoQ10 production in detail.

[Direct mechanism of action in toxic myopathies]

Toxic myopathies are a large group of disorders generated by surrounding agents and characterized by structural and/or functional disturbances of muscles. The most recurrent are those induced by commonly used medications. Illicit drugs, environmental toxins from animals, vegetables, or produced by micro-organisms as well as chemical products commonly used are significant causes of such disorders. The muscle toxicity results from multiple mechanisms at different biological levels. Many agents can induce myotoxicity through a direct mechanism in which statins, glucocorticoids and ethyl alcohol are the most representative. Diverse mechanisms were highlighted as interaction with macromolecules and induction of metabolic and cellular dysfunctions. Muscle damage can be related to amphiphilic properties of some drugs (chloroquine, hydroxychloroquine, etc.) leading to specific lysosomal disruptions and autophagic dysfunctions. Some agents affect the whole muscle fiber by inducing oxidative stress (ethyl alcohol and some statins) or triggering cell death pathways (apoptosis or necrosis) resulting in extensive alterations. More studies on these mechanisms are needed. They would allow a better knowledge of the intracellular mediators involved in these pathologies in order to develop targeted therapies of high efficiency.

Translational insight into statin-induced muscle toxicity: from cell culture to clinical studies

Statins are lipid-lowering drugs used widely to prevent and treat cardiovascular and coronary heart diseases. These drugs are among the most commonly prescribed medicines intended for long-term use. In general, statins are well tolerated. However, muscular adverse effects appear to be the most common obstacle that limits their use, resulting in poor patient compliance or even drug discontinuation. In addition, rare but potentially fatal cases of rhabdomyolysis have been reported with the use of these drugs, especially in the presence of certain risk factors. Previous reports have investigated statin-induced myotoxicity in vivo and in vitro using a number of cell lines, muscle tissues, and laboratory animals, in addition to randomized clinical trials, observational studies, and case reports. None of them have compared directly results from laboratory investigations with clinical observations of statin-related muscular adverse effects. To the best of our knowledge this is the first review article that combines laboratory investigation with clinical aspects of statin-induced myotoxicity. By reviewing published literature of in vivo, in vitro, and clinically relevant studies of statin myotoxicity, we aim to translate this important drug-related problem to establish a clear picture of proposed mechanisms that explain the risk factors and describe the diagnostic approaches currently used for evaluating the degree of muscle damage induced by these agents. This review provides baseline novel translational insight that can be used to enhance the safety profile, to minimize the chance of progression of these adverse effects to more severe and potentially fatal rhabdomyolysis, and to improve the overall patient compliance and adherence to long-term statin therapy.

Evaluation of ubiquinone concentration and mitochondrial function relative to cerivastatin-induced skeletal myopathy in rats

As a class, hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors can potentially cause skeletal myopathy. One statin, cerivastatin, has recently been withdrawn from the market due to an unacceptably high incidence of rhabdomyolysis. The mechanism underlying statin-induced myopathy is unknown. This paper sought to investigate the relationship among statin-induced myopathy, mitochondrial function, and muscle ubiquinone levels. Rats were administered cerivastatin at 0.1, 0.5, and 1.0 (mg/kg)/day or dose vehicle (controls) by oral gavage for 15 days. Samples of type I-predominant skeletal muscle (soleus) and type II-predominant skeletal muscle [quadriceps and extensor digitorum longus (EDL)], and blood were collected on study days 5, 10, and 15 for morphological evaluation, clinical chemistry, mitochondrial function tests, and analysis of ubiquinone levels. No histological changes were observed in any of the animals on study days 5 or 10, but on study day 15, mid- and high-dose animals had necrosis and inflammation in type II skeletal muscle. Elevated creatine kinase (CK) levels in blood (a clinical marker of myopathy) correlated with the histopathological diagnosis of myopathy. Ultrastructural characterization of skeletal muscle revealed disruption of the sarcomere and altered mitochondria only in myofibers with degeneration, while adjacent myofibers were unaffected and had normal mitochondria. Thus, mitochondrial effects appeared not to precede myofiber degeneration. Mean coenzyme Q9 (CoQ9) levels in all dose groups were slightly decreased relative to controls in type II skeletal muscle, although the difference was not significantly different in most cases. Mitochondrial function in skeletal muscle was not affected by the changes in ubiquinone levels. The ubiquinone levels in high-dose-treated animals exhibiting myopathy were not significantly different from low-dose animals with no observable toxic effects. Furthermore, ubiquinone levels did not correlate with circulating CK levels in treated animals. The results of this study suggest that neither mitochondrial injury, nor a decrease in muscle ubiquinone levels, is the primary cause of skeletal myopathy in cerivastatin-dosed rats.