Arterial pressure suffices to increase liver stiffness

Area of Science:

• Hepatology
• Cardiovascular Physiology
• Medical Imaging

Background:

• Noninvasive liver stiffness (LS) measurement is vital for screening liver fibrosis.
• Elevated LS can also indicate pressure-related conditions like liver congestion.
• The influence of arterial pressure on LS requires further investigation.

Purpose of the Study:

• To investigate the direct role of arterial pressure in modulating liver stiffness.
• To assess the impact of changes in arterial pressure on LS in both healthy and fibrotic rat models.
• To explore the potential of modulating arterial pressure for managing LS.

Main Methods:

• Liver stiffness was measured using transient elastography (μFibroscan).
• Arterial and venous pressures were monitored in anesthetized rats using the PowerLab device.
• Catecholamines (epinephrine, norepinephrine) were used to increase arterial pressure, and glycerol trinitrate (GTN) was used to decrease it.
• Studies were conducted in rats with and without thioacetamide (TAA)-induced fibrosis, and in humans during exercise.

Main Results:

• In rats, epinephrine and norepinephrine administration significantly increased mean arterial pressure (MAP) and nearly doubled LS, while central venous and portal pressures remained largely unchanged.
• In TAA-induced fibrotic rats, LS increased dramatically upon epinephrine injection and was effectively reduced by GTN.
• In humans, elevated MAP during exercise correlated with a significant increase in LS.
• Baseline LS in rats was comparable to human values.

Conclusions:

• Arterial pressure is a sufficient factor to increase liver stiffness.
• Pharmacological reduction of arterial pressure can effectively decrease LS in fibrotic livers.
• These findings highlight the importance of considering hemodynamic factors in liver stiffness assessment and management.