Alzheimer's disease pathogenesis: standing at the crossroad of lipid metabolism and immune response.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by macroscopic features such as cortical atrophy, narrowing of the gyri, widening of the sulci, and enlargement of the ventricles. At the cellular level, the pathological characteristics include the extracellular aggregation of β-amyloid (Aβ) forming senile plaques, and the intracellular accumulation of hyperphosphorylated tau proteins forming neurofibrillary tangles. AD leads to the progressive decline of cognitive, behavioral, and social abilities, with no effective treatment available currently. The pathophysiology of AD is complex, involving mechanisms such as immune dysregulation and lipid metabolism alterations. Immune cells, such as microglia, can identify and clear pathological aggregates like Aβ early in the disease. However, prolonged or excessive activation of immune cells may trigger chronic neuroinflammation, thereby accelerating neuronal damage and the progression of AD. Lipid metabolism plays a critical role in maintaining cell membrane structure and function, regulating the production and clearance of Aβ, and supplying energy to the brain. Disruptions in these processes are closely linked to the pathological progression of AD. The interaction between lipid metabolism and the immune system further exacerbates the disease progression of AD. In this review, we discuss the lipid metabolism and immune response in AD, summarize their intricate interactions, and highlight the complexity of the multifactorial pathogenic cascade, offering insights into new interventions targeting the immune-metabolic axis in AD.