Neuritic plaques

Neuritic plaques, also known as senile plaques, are extracellular deposits of beta-amyloid peptide in the grey matter of the brain. They are a pathological hallmark of Alzheimer's disease, a neurodegenerative disorder characterized by memory loss and cognitive decline.

Structure and Composition

Neuritic plaques are primarily composed of beta-amyloid, a peptide of 39-43 amino acids. This peptide is produced by the cleavage of the larger amyloid precursor protein (APP) by two enzymes, beta-secretase and gamma-secretase. The plaques also contain other components, such as neurofibrillary tangles, neurons, and glial cells.

Pathogenesis

The formation of neuritic plaques is a complex process that involves the aggregation of beta-amyloid into insoluble fibrils, the recruitment of glial cells, and the dystrophy of neuronal processes. The exact mechanisms underlying this process are still not fully understood, but it is believed to involve a combination of genetic, environmental, and age-related factors.

Clinical Significance

Neuritic plaques are one of the key pathological features of Alzheimer's disease. They are found in high numbers in the brains of individuals with this condition, particularly in regions involved in memory and cognition, such as the hippocampus and the cerebral cortex. The presence of these plaques is associated with neuronal loss and cognitive decline, although the exact relationship between plaques and disease symptoms is still a matter of debate.

See Also

• Alzheimer's disease
• Beta-amyloid
• Amyloid precursor protein
• Neurofibrillary tangles

Neuritic plaques Resources
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References

External Links

• Alzheimer's Association
• National Institute on Aging - Alzheimer's

Further Reading

• Selkoe, D. J. (2001). Alzheimer's disease: genes, proteins, and therapy. Physiological reviews, 81(2), 741-766.
• Hardy, J., & Selkoe, D. J. (2002). The amyloid hypothesis of Alzheimer's disease: progress and problems on the road to therapeutics. Science, 297(5580), 353-356.
• Goedert, M., & Spillantini, M. G. (2006). A century of Alzheimer's disease. Science, 314(5800), 777-781.