Neurodegeneration and aging: pathophysiology, diagnosis, and therapeutic targets.

Aging is the greatest risk factor for AD, ALS, PD, FTD, and HD. Neurons in the brain experience many changes as people age, negatively affecting their structure and function. It examines the key processes behind brain aging, such as age-related death of cells, failure of the cells' powerhouses, oxidative stress, incorrect protein shapes, brain inflammation, difficulty in cleaning the brain, and deterioration of blood vessels, and shows their impact on neurodegeneration. With age, there are difficulties in brain-blood circulation, less synaptic change, and fewer new neurons, which make the disease even worse. Informed by human and animal trials, we see that mitochondria work less efficiently in aging brain cells, while oxidative damage to DNA increases doubly to triply. In addition, too much tau, amyloid-β, and α-synuclein building up is tied to declining mental abilities in the elderly. We further evaluate new tests that help with early detection and classification, for example, using biomarkers in cerebrospinal fluid (CSF), blood panels, detailed brain scans, and AI algorithms. It stresses that more aging-specific trials, better integration of multi-omics, and increased interest in research on the gut-brain axis are important. The communication between the aging of the body and the brain is also explained. This article covers the main cellular, molecular, and clinical issues linked to brain aging and highlights important future research areas needed to develop effective treatments for aging people.