[Biotransformation in liver damage].

Area of Science:

• Pharmacology and Toxicology
• Hepatology
• Drug Metabolism

Context:

• Xenobiotics can cause liver damage, and conversely, primary liver diseases alter drug metabolism and elimination.
• The liver's monooxygenase system (cytochrome P450 isoenzymes) metabolizes drugs, and its activity can be modulated by factors like hormones, smoking, and alcohol.
• Severe liver diseases, such as cirrhosis, notably reduce drug biotransformation.

Purpose:

• To investigate the relationship between liver diseases and drug biotransformation processes.
• To assess how liver damage affects the activity of key drug-metabolizing enzymes.
• To correlate specific liver pathologies with alterations in drug metabolism and elimination.

Summary:

• Liver diseases can significantly impair drug metabolism, with severe conditions like cirrhosis leading to increased excretion of unchanged drugs (e.g., furosemide) and altered bioavailability (e.g., propranolol).
• Genetic factors (slow acetylators) and conditions like drug hepatitis and hemochromatosis are associated with reduced Phase I cytochrome P450 activity.
• Measuring 7-ethoxycoumarin-O-deethylase (ECOD) in liver biopsies can link decreased biotransformation to liver cell necrosis, fibrosis, and structural damage, potentially related to impaired liver regeneration ('streaming liver' concept).

Impact:

• Highlights the critical role of liver function in drug efficacy and safety.
• Provides insights into personalized medicine approaches by considering liver health and genetic predispositions in drug therapy.
• Suggests potential links between drug metabolism dysfunction, liver pathology, and regenerative processes in liver disease.