Metallothionein Expression in Horses With Chronic Liver Disease and Its Correlation With Ki-67 Immunoreactivity.
Authors: Verhoef Jolanda N C, Allen Andrew L, Harding John C S, Al-Dissi Ahmad N
Journal: Veterinary pathology
Summary
# Metallothionein Expression in Equine Chronic Liver Disease: Implications for Regeneration and Inflammation Metallothionein (MT), a protein with established regenerative, antifibrotic, and anti-inflammatory properties in human medicine, had never been systematically examined in equine chronic liver disease until this 2018 investigation. Verhoef and colleagues conducted immunohistochemical analysis on liver biopsies from 77 horses with chronic liver disease, quantifying MT expression alongside Ki-67 immunoreactivity (a marker of active cellular proliferation) and histopathological scores for inflammation, fibrosis, and bile duct proliferation. MT expression was detected in 94.8% of diseased livers, with significant correlations between MT and Ki-67 staining specifically in bile duct epithelium and resident Kupffer cells; notably, livers with lymphocytic infiltrates showed significantly higher median MT expression than those without infiltration. These findings suggest that MT upregulation may represent an endogenous hepatoprotective response during chronic equine liver disease, potentially linked to enhanced cellular regeneration and immune cell activity. Given that equine chronic liver disease currently lacks disease-modifying therapies beyond supportive care, understanding the role of naturally occurring MT expression warrants further investigation into whether therapeutic MT augmentation could be developed to modulate inflammation and promote hepatocellular recovery in affected horses.
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Practical Takeaways
- •MT expression is nearly universal in equine chronic liver disease and correlates with immune cell activation; this foundational knowledge may support future therapeutic strategies targeting MT to enhance liver regeneration
- •The strong association between MT and Kupffer cell/bile duct activity suggests MT plays a role in the liver's inflammatory and regenerative response; monitoring MT expression could potentially help assess disease progression or treatment response
- •These findings are preliminary and descriptive; current treatment of equine chronic liver disease remains supportive, and MT-targeted therapies are not yet clinically available for horses
Key Findings
- •Metallothionein (MT) expression was observed in 94.8% (73/77) of chronically diseased equine livers
- •MT expression was significantly associated with Ki-67 staining in bile duct epithelium and Kupffer cells, suggesting a link between MT and hepatocellular regeneration
- •Median MT expression was significantly higher in cases with lymphocytic infiltrates compared to cases without lymphocytic infiltrate (P < 0.05)
- •Ki-67 immunoreactivity was most prominent in Kupffer cells (54.6%) and lymphocytes (50.7%), with lower expression in bile duct epithelium (13.0%) and hepatocytes (10.4%)