Alzheimer type II astrocyte

Alzheimer Type II Astrocyte

Alzheimer type II astrocyte under high magnification

Alzheimer type II astrocytes are a specific type of astrocyte that are characterized by their distinct morphological features and are associated with certain pathological conditions, particularly those involving hepatic encephalopathy. These cells are named after the German psychiatrist and neuropathologist Alois Alzheimer, who is also known for his work on Alzheimer's disease.

Characteristics

Alzheimer type II astrocytes are typically identified by their enlarged nuclei, which are pale and contain prominent nucleoli. The cytoplasm of these cells is often scant, and they may exhibit a swollen appearance. These astrocytes are not related to Alzheimer's disease, despite the name, but are instead associated with metabolic disturbances in the brain.

Pathophysiology

Alzheimer type II astrocytes are most commonly observed in the context of hepatic encephalopathy, a condition that arises due to liver dysfunction. In this condition, the liver is unable to adequately detoxify the blood, leading to the accumulation of toxic substances such as ammonia. These toxins can cross the blood-brain barrier and affect the central nervous system, resulting in the characteristic changes seen in astrocytes.

The presence of Alzheimer type II astrocytes is indicative of hyperammonemia and other metabolic derangements. The exact mechanism by which these astrocytes form is not fully understood, but it is believed to involve the direct effects of elevated ammonia levels on astrocytic function and structure.

Clinical Significance

The identification of Alzheimer type II astrocytes in brain tissue can be an important diagnostic clue in cases of unexplained neurological symptoms, particularly when liver disease is suspected. These astrocytes are typically found in the gray matter of the brain, especially in the cerebral cortex and basal ganglia.

In addition to hepatic encephalopathy, Alzheimer type II astrocytes may also be seen in other conditions associated with metabolic disturbances, such as Wilson's disease and Reye's syndrome.

Histological Examination

Under the microscope, Alzheimer type II astrocytes are identified by their large, pale-staining nuclei and prominent nucleoli. Special staining techniques may be used to highlight these features and differentiate them from other types of astrocytes and glial cells.

Related Pages

• Astrocyte
• Hepatic encephalopathy
• Hyperammonemia
• Blood-brain barrier
• Wilson's disease
• Reye's syndrome