Laboratory Medicine in the Clinical Decision Support for Treatment of Hypercholesterolemia: Pharmacogenetics of Statins

Investigation of the Effect of Atorvastatin on Skeletal Muscles in Male Rats and the Involved Mechanisms

It has been approved that atrovastatin is a preferred treatment for hyperlipidemia. One of the atrovastatin drawbacks would be the detrimental effects on skeletal muscles. Therefore, the current study was designed to evaluate all the skeletal muscles alteration in rats' after administration of atrovastatin and identification the mechanisms involved in these structural alterations in the skeletal muscles. A total of 12 healthy adult male rats (Rattus norvegicus) were randomly divided into two groups (n=6). The control group (G1) included rats that received distilled water as the placebo, and the treatment group (G2) included animals that were treated with atorvastatin (80 mg/kg/day) dissolved in distilled water and administrated by a gastric tube for eight weeks. At the end of the experiment, trapezius and vastus medialis muscle tissues were sampled and fixed with 10% formalin for histopathological studies. Atorvastatin administration gave rise to morphological changes in the skeletal muscle fibers and the nerve fibers, including atrophied myofibers, infarction, irregular arrangement of myonuclei, disappearance of nuclei from their normal peripheral position with acute skeletal muscular infarction, and infiltration of accumulated inflammatory cells. Atorvastatin has been revealed to have several adverse effects on the skeletal muscle and the nerve supply. Based on the data in the current study, it is evident that atorvastatin administration for less than two months resulted in some sorts of myotoxic structural changes and apoptosis as evident by deformity and lack of striation degeneration of nuclei, as well as splitting of the muscle fibers in the adult male rats' skeletal muscle.

How I treat statin-associated side effects in an outpatient setting

Dyslipidemia promotes atherosclerosis and causes cardiovascular diseases. Statins are potent lipid-lowering medications with a cardiovascular mortality benefit. They are generally safe and well tolerated but sometimes can be associated with side effects of variable severity. The most common side effect is statin-associated muscle symptoms. Uncommon side effects include new-onset diabetes mellitus and elevation in liver enzymes. These effects can lead to noncompliance and premature discontinuation of the medication. Hence, it is crucial to identify patients with true statin-associated side effects (SASE) to ensure optimal statin use. The appropriate evaluation of the patient before starting statins and proactive utilization of available diagnostic tests to rule out alternate etiologies mimicking adverse effects are essential for accurate diagnosis of SASE. In patients with true SASE, timely intervention with modified statin or non-statins is beneficial. Herein, we discuss key clinical trial data on statins and non-statins, and describe our center's approach toward patients with SASE.

Lovastatin Inhibits Cancer Stem Cells and Sensitizes to Chemo- and Photodynamic Therapy in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated malignancy occurring at high incidence in Southeast Asia and southern China. In spite of the good response to radio- and chemo-therapy at the early stage, resistance and recurrence develop in NPC patients in the advanced setting. Cancer stem cells (CSCs) play an important role in drug resistance and cancer recurrence. Here we report that lovastatin, a natural compound and a lipophilic statin that has already been used in the clinic to treat hypercholesterolemia, inhibited the CSC properties and induced apoptosis and cell cycle arrest in sphere-forming cells derived from the 5-8F and 6-10B NPC cell lines. Furthermore, lovastatin conferred enhanced sensitivity to the chemotherapeutic and photodynamic agents in NPC CSCs. Together our findings suggest that targeting CSCs by lovastatin in combination with routine chemotherapeutic drugs or photodynamic therapy might be a promising approach to the treatment of NPC.