Mitochondrial Dysfunction and Endoplasmic Reticulum Stress in Chronic Pain.

Chronic pain is a major global health burden and often remains difficult to treat with current therapies, which frequently provide incomplete relief and may cause systemic side effects. As essential organelles in eukaryotic cells, mitochondria facilitate ATP synthesis and serve as key regulators of calcium homeostasis and apoptosis. Evidence points to mitochondrial dysfunction not merely as a result of trauma, but as a fundamental factor in why pain becomes persistent. On the other hand, the endoplasmic reticulum (ER) is more than just a structural component of the cell; it is a multi-functional organelle responsible for protein quality control, including folding and degradation, as well as lipid production and calcium signaling. ER dysfunction is a primary driver of various pathologies, such as cardiovascular disease, cancer, and neurodegenerative disorders. The organelle's ability to execute its vital functions is strictly dependent on sufficient levels of ATP. Because mitochondrial and ER functions are closely interconnected through calcium exchange, ATP-dependent protein homeostasis, oxidative stress, and mitochondria-associated ER membranes, their dysfunction may act together to amplify nociceptive sensitization and pain chronification. In this review, we summarize current evidence linking mitochondrial dysfunction, ER stress, and ER-mitochondrial crosstalk to the pathogenesis of chronic pain and discuss their potentials as therapeutic targets.