Myelin in Alzheimer's disease: culprit or bystander?

Area of Science:

• Neuroscience
• Neuropathology
• Biochemistry

Background:

• Alzheimer's disease (AD) involves neuronal loss due to toxic amyloid-beta (Aβ) oligomers, plaques, and tau tangles.
• Sporadic AD, more common than familial forms, involves chronic neuroinflammation, mitochondriopathies, and free radical accumulation.
• Accumulated misfolded proteins in the aged brain trigger amyloidosis, damaging myelin sheaths and axons, leading to cognitive deficits.

Purpose of the Study:

• To investigate the potential role of early myelin alterations in Alzheimer's disease pathogenesis.
• To explore if dysmyelination precedes or contributes significantly to neuronal damage and cognitive symptoms in AD.
• To question the primary role of amyloid peptides in initiating neuropathology in certain forms of AD.

Main Methods:

• Review of existing literature on Alzheimer's disease pathology.
• Analysis of the proposed mechanisms linking myelin alterations to neurodegeneration.
• Hypothetical modeling of dysmyelination's role in AD onset and progression.

Main Results:

• Myelin composition and architecture may be an early target for toxic Aβ peptides and other hydrophobic misfolded proteins.
• Early myelin alterations could be a key factor in the genesis of neuronal damage and AD symptomatology.
• Structural and metabolic disorders in myelination/demyelination processes may underlie specific pathophysiological and clinical forms of AD.

Conclusions:

• Dysmyelination, rather than amyloid peptides, might initiate neuropathology in some Alzheimer's disease cases.
• Altered myelination processes could be a primary driver of neuronal dysfunction and cognitive decline in AD.
• This perspective shifts focus towards myelin integrity as a critical factor in Alzheimer's disease.