Dual Stages of Alcohol-Related Cerebral White Matter Degeneration Reviewed: Early-Stage Stress/Neuroinflammation Versus Late-Stage Impaired Insulin/IGF Signaling Through Akt-mTOR-Review.

Long-term effects of alcohol-related brain damage (ARBD) include neurocognitive and neurobehavioral dysfunctions with neurodegeneration. White matter (WM) is notably targeted across the lifespan yet relatively little is known about the stages, mechanisms, and consequences of myelin and axonal loss. In alcohol-related liver disease, early pathology is reversible, but with chronic heavy alcohol exposures, disease progresses with degeneration, and ultimately organ failure. Similarly, WM ARBD also develops in two broad stages. The early stages of WM ARBD are likely mediated by vascular dysfunction with tissue swelling, oligodendrocyte dysfunction, myelin loss, neuroinflammation, and oxidative stress. The chronic progressive stage is linked to metabolic dysfunction related to impairments in insulin and insulin-like growth factor signaling through Akt-mechanistic target of rapamycin (mTOR) pathways that mediate oligodendrocyte survival and function, myelin homeostasis, and blood-brain-barrier (BBB) integrity. We hypothesize that early-stage WM ARBD may be largely reversible by abstinence and anti-oxidant/anti-inflammatory measures, whereas late-stage ARBD requires strategies to restore WM/oligodendrocyte metabolic function via insulin sensitizer, antioxidant, anti-inflammatory, and myelin homeostasis/normalization support. Multi-pronged, overlapping but distinct therapeutic strategies are needed to reduce the impact and long-term health consequences of chronic progressive WM ARBD.