Liver as a key organ for systemic antimicrobial defense

Area of Science:

• Immunology
• Hepatology
• Microbiology

Background:

• Chronic liver disease (CLD) involves persistent liver inflammation and regeneration, leading to cirrhosis and heightened susceptibility to microbial infections.
• Infections in CLD patients can cause acute decompensation and poor outcomes, while CLD exacerbates infection severity, creating a detrimental cycle.
• Liver cells, including hepatocytes, Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs), and biliary epithelial cells, exhibit diverse roles in antimicrobial immunity.

Purpose of the Study:

• To comprehensively summarize the roles of various hepatic cell types in combating microbial infections, particularly bacterial infections.
• To explore the mechanisms contributing to increased infection susceptibility in patients with chronic liver disease.

Main Methods:

• Literature review and synthesis of recent research on hepatic cell functions during infection.
• Focus on the coordinated immune responses involving hepatocytes, nonparenchymal liver cells, and immune components.

Main Results:

• Hepatocytes produce antimicrobial peptides and inflammatory mediators.
• Kupffer cells capture pathogens, while LSECs manage immune cell trafficking and pathogen sensing.
• HSCs contribute to fibrosis via inflammasome and TGF-β signaling; biliary epithelial cells act as frontline defenders.

Conclusions:

• Understanding the intricate interactions between different liver cells and immune components is essential for developing effective therapies.
• Targeted therapies aimed at modulating hepatic cell functions could improve infection control and clinical outcomes in chronic liver disease patients.