Kallikrein-kinin system in hepatic experimental models

Area of Science:

• Biochemistry
• Physiology
• Hepatology

Background:

• The kallikrein-kinin system (KKS) is crucial for regulating blood pressure and inflammation.
• The liver's specific role within the KKS, particularly in relation to bradykinin metabolism and its effects, requires detailed characterization.

Purpose of the Study:

• To review the characteristics of the kallikrein-kinin system (KKS) within the liver.
• To elucidate the liver's functions in synthesizing and clearing KKS components.
• To describe the distinct effects of bradykinin (BK) in the liver compared to its systemic actions.

Main Methods:

• Literature review focusing on studies of the KKS in hepatic tissue.
• Analysis of protein synthesis and clearance mechanisms in the liver related to KKS factors.
• Examination of the signaling pathways and receptor interactions of bradykinin in the liver.

Main Results:

• The liver synthesizes kininogens and prekallikrein, with increased production during acute phase reactions in rats.
• The liver is the primary organ for clearing plasma and tissue kallikrein from circulation.
• Bradykinin (BK) induces a portal hypertensive response in the liver, mediated by B2 receptors on sinusoidal cells.
• BK hydrolysis occurs via angiotensin-converting enzyme, predominantly in the perivenous region.

Conclusions:

• The liver is a central organ in the kallikrein-kinin system, involved in both synthesis and clearance.
• Bradykinin exerts unique physiological effects within the liver, leading to portal hypertension.
• Understanding these hepatic KKS functions is vital for comprehending liver physiology and pathology.