Abstract # 1746 Inflammation and mitochondrial dysfunction in elderly women with major depressive disorder

Abstract

Inflammatory processes are supposed to play an integral role in the pathophysiology of Major Depressive Disorder (MD). Chronically elevated levels of CRP, IL-6 and TNF-alpha may contribute to the high prevalence of secondary diseases observed with MD (e.g. autoimmune diseases, cardiovascular diseases, and cancer). Besides poor health outcomes, MD patients suffer from chronic fatigue, lack of energy and difficulties concentrating. These core symptoms of depression point towards disturbances in physiological energy homeostasis. The main energy suppliers of human cells, mitochondria, are in addition to the production of adenosine triphosphate (ATP), pivotally involved in the regulation of inflammatory processes. To this end, we analyzed in a study cohort of 44 elderly women (22 MD patients and 22 healthy age-matched controls) whether mitochondrial activity was altered in immune cells of MD patients and was associated with inflammation as assessed by serum CRP, IL-6 and TNF-alpha levels. Compared to healthy controls, MD patients presented in tendency higher levels of circulating CRP, IL-6, but not TNF-alpha. Mitochondrial activity, mitochondrial maximal capacity and oxygen consumption related to ATP production were substantially reduced in immune cells of MD patients. Maximal capacity was reduced and mitochondria were operating closer to their maximal capacity with higher levels of inflammation. Together these data support the hypothesis that immune dysregulation and mitochondrial dysfunction are possibly interconnected and inherent in the pathophysiology of MD.