Alpha-I-antitrypsin and copper in the liver

Area of Science:

• Hepatology
• Biochemistry
• Histochemistry

Background:

• Alpha-1-antitrypsin (AAT) accumulation in the liver is a known condition.
• Orcein positive granules, indicative of copper-associated protein, were incidentally observed in AAT-positive liver biopsies.
• This observation prompted a detailed investigation into copper presence in AAT-related liver disease.

Purpose of the Study:

• To investigate the presence and extent of copper and copper-binding protein accumulation in liver biopsies with histological evidence of AAT accumulation.
• To determine the correlation between AAT accumulation, copper deposition, and the severity of liver damage.
• To explore the potential link between disturbed AAT metabolism and altered copper metabolism in hepatocytes.

Main Methods:

• Histochemical analysis of 46 liver biopsies with confirmed AAT accumulation.
• Use of orcein and rhodanine stains to detect copper and copper-binding proteins.
• Correlation analysis between copper deposition, AAT presence, and histological grading of liver damage (cirrhosis).

Main Results:

• Copper and copper-binding proteins were detected in 71.73% of the studied liver biopsies.
• All 19 cirrhotic livers (100%) showed copper accumulation, compared to 51.85% of non-cirrhotic livers.
• AAT and copper deposits were found to coexist within the same periportal hepatocytes, with AAT globules reacting positively to stains.
• A significant correlation was observed between the severity of chronic liver damage and the amount of copper deposition.

Conclusions:

• Hepatocytes in AAT accumulation exhibit co-deposition of AAT and copper.
• AAT storage is associated with impaired copper metabolism and excretion, leading to intracellular copper accumulation.
• The findings suggest that AAT-related liver disease involves a complex interplay between AAT and copper metabolism pathways.