Glutamine synthetase staining patterns in cirrhosis

Area of Science:

• Hepatology
• Pathology
• Immunohistochemistry

Background:

• Advanced liver fibrosis can potentially regress after addressing the underlying cause.
• Glutamine synthetase (GS) expression typically occurs in centrizonal hepatocytes but can shift to the periportal region in regressed cirrhosis.
• Understanding GS staining patterns may offer insights into liver disease progression and regression.

Purpose of the Study:

• To investigate the spectrum of Glutamine Synthetase (GS) staining patterns in cirrhotic livers.
• To identify and characterize periportal GS staining in various stages and etiologies of liver fibrosis.
• To evaluate the utility of GS staining in differentiating regressed from non-regressed cirrhotic cases.

Main Methods:

• Review of 88 liver resection/explant specimens with advanced fibrosis.
• Hematoxylin and eosin (H&E) and GS immunohistochemical staining.
• Trichrome and orcein stains used for classification into progressive, indeterminate, or regressive categories.

Main Results:

• Periportal GS staining was observed in 97% of regressive and 84% of progressive/indeterminate cases.
• Diverse GS staining patterns were identified, including perivenular, periseptal, and perinodular.
• The GS periseptal pattern was more frequent in regressed cirrhosis; perinodular staining was associated with cholestasis in 75% of cases.

Conclusions:

• Periportal GS staining is a common finding across different patterns of cirrhosis.
• GS immunohistochemistry, while showing varied patterns, is less reliable than orcein/trichrome staining for distinguishing regressed from non-regressed cirrhosis.