Little is known about the effects of statins, which are cholesterol-lowering drugs, on the bioenergetic functions of mitochondria in the brain. This study aimed to elucidate the direct effects of atorvastatin and simvastatin on the bioenergetics of isolated rat brain mitochondria by measuring the statin-induced changes in respiratory chain activity, ATP synthesis efficiency, and the production of reactive oxygen species (ROS). Our results in isolated brain mitochondria are the first to demonstrate that atorvastatin and simvastatin dose-dependently significantly inhibit the activity of the mitochondrial respiratory chain, resulting in a decreased respiratory rate, a decreased membrane potential, and increased ROS formation. Moreover, the tested statins reduced mitochondrial coupling parameters, the ADP/O ratio, the respiratory control ratio, and thus, the oxidative phosphorylation efficiency in brain mitochondria. Among the oxidative phosphorylation complexes, statin-induced mitochondrial impairment concerned complex I, complex III, and ATP synthase activity. The calcium-containing atorvastatin had a significantly more substantial effect on isolated brain mitochondria than simvastatin. The higher inhibitory effect of atorvastatin was dependent on calcium ions, which may lead to the disruption of calcium homeostasis in mitochondria. These findings suggest that while statins are effective in their primary role as cholesterol-lowering agents, their use may impair mitochondrial function, which may have consequences for brain health, particularly when mitochondrial energy efficiency is critical.

Statins are commonly used cholesterol-lowering drugs, but their effects on astrocyte oxidative metabolism are poorly understood. To investigate this, rat astrocytes were exposed to 200 nM atorvastatin or simvastatin for 6 days and then assessed for changes in coenzyme Q (CoQ) homeostasis, mitochondrial function, and energy metabolism. Both statins comparably decreased cellular CoQ9 and CoQ10 levels (~35%), with greater losses of their reduced antioxidant forms (60–75%). Lower intracellular and mitochondrial levels of reactive oxygen species (ROS) were accompanied by the upregulation of nuclear factor erythroid 2-related factor 2 (NRF2)-dependent antioxidant pathways (superoxide dismutase 1 and glutathione reductase) and metabolic stress response factors, including hypoxia-inducible factor 1-alpha (HIF1α) and brain-derived neurotrophic factor (BDNF). Both statins promoted glycolytic reprogramming, mitochondrial fission, and biogenesis while impairing oxidative phosphorylation, as evidenced by reduced ATP-linked respiration, increased proton leak, and lower ATP levels. These findings suggest that statin-treated astrocytes adapt by prioritizing redox homeostasis over ATP production. CoQ10 supplementation increased cellular CoQ10 levels and restored ATP levels without further decreasing ROS, suggesting that its primary benefit is bioenergetic support, not additional antioxidant protection. Overall, statin-induced CoQ deficiency induces adaptive metabolic remodeling of astrocytes, while CoQ10 supplementation may help maintain energy metabolism under these conditions.