Statin-induced Ca(2+) release was increased in B lymphocytes in patients who showed elevated serum creatine kinase...

Statins are effective in lowering cholesterol levels, but cause fatal rhabdomyolysis in susceptible individuals. Because it has been hypothesized that muscle damage could result from alterations in Ca(2+) homeostasis in muscle cells, we tested whether measuring statin-induced changes in intracellular calcium ([Ca(2+)](i)) is useful for predicting susceptibility to statin-muscle damage, using human CD19+ primary B lymphocytes.

Statin-induced alterations in [Ca(2+)](i) were studied using the human THP-1 cell line and CD19+ primary B lymphocytes. Changes in [Ca(2+)](i) were measured directly in fluo-3- loaded cells using either single or dual-color flow cytometry.

The Ca(2+) release study suggested that statin-induced changes in [Ca(2+)](i) were due to Ca(2+) release from ryanodine-sensitive Ca(2+) stores and mitochondrial compartments. Further, statin users who experienced elevated creatine kinase (n=8) exhibited significantly greater statin-induced Ca(2+) release in B cells than healthy volunteers (n=45) and statin users without elevated creatine kinase (n=16), while no difference was seen between the latter two groups.

Statin-induced Ca(2+) release from ryanodine-sensitive stores and mitochondria may contribute to myotoxicity. The laboratory test for Ca(2+) release using CD19+ primary B lymphocytes may be useful to predict susceptibility to statin-induced muscle toxicity prior to statin use.