The Role of Autophagy in Critical Illness-induced Liver Damage

Area of Science:

• Cellular Biology
• Organelle Dysfunction
• Critical Care Medicine

Background:

• Mitochondrial dysfunction and endoplasmic reticulum (ER) stress, activating the unfolded protein response (UPR), are key in critical illness-induced organ failure, particularly liver failure.
• Autophagy mitigates these stresses, but its suppression in prolonged illness correlates with organ failure, though its precise role in acute settings is unclear.

Purpose of the Study:

• To investigate if impaired hepatic autophagy activation during critical illness exacerbates liver damage by increasing mitochondrial dysfunction and affecting the UPR.
• To determine the impact of hepatic autophagy inactivation on liver injury markers in acute and prolonged critical illness.

Main Methods:

• Utilized a mouse model of critical illness induced by surgery and sepsis.
• Assessed hepatic mitochondrial function, UPR markers, and liver damage markers at acute (1 day) and prolonged (3 days) time points after autophagy inactivation.

Main Results:

• Inactivating hepatic autophagy during critical illness acutely worsened mitochondrial dysfunction.
• Autophagy inactivation modulated the hepatic UPR in a time-dependent manner and aggravated liver damage markers at both acute and prolonged time points.

Conclusions:

• The inability to acutely activate hepatic autophagy during critical illness exacerbates mitochondrial damage and dysfunction.
• Impaired autophagy partially prohibits acute UPR activation and worsens liver injury, highlighting autophagy's critical role in preventing critical illness-induced liver failure.