Summary
Little is known about the regulation of high-molecular-weight-kininogen (HK) and low-molecular-weight-kininogen
(LK) or the relationship of each to the degree of liver function impairment in patients
with cirrhosis. In this study, we evaluated HK and LK quantitatively by a recently
described particle concentration fluorescence immunoassay (PCFIA) and qualitatively
by SDS PAGE and immunoblotting analyses in plasma from 33 patients with cirrhosis
presenting various degrees of impairment of liver function. Thirty-three healthy subjects
served as normal controls. Patients with cirrhosis had significantly lower plasma
levels of HK (median 49 μg/ml [range 22-99 μg/ml]) and LK (58 μg/ml [15-100 μg/ml])
than normal subjects (HK 83 μg/ml [65-115 μg/ml]; LK 80 μg/ml [45-120 μg/ml]) (p <
0.0001). The plasma concentrations of HK and LK were directly related to plasma levels
of cholinesterase (P < 0.0001) and albumin (P < 0.0001 and P < 0.001) and inversely
to the Child-Pugh score (P < 0.0001) and to prothrombin time ratio (P < 0.0001) (reflecting
the clinical and laboratory abnormalities in liver disease). Similar to normal individuals,
in patients with cirrhosis, plasma HK and LK levels paralleled one another, suggesting
that a coordinate regulation of those proteins persists in liver disease. SDS PAGE
and immunoblotting analyses of kininogens in cirrhotic plasma showed a pattern similar
to that observed in normal controls for LK (a single band at 66 kDa) with some lower
molecular weight forms noted in cirrhotic plasma. A slight increase of cleavage of
HK (a major band at 130 kDa and a faint but increased band at 107 kDa) was evident.
The increased cleavage of HK was confirmed by the lower cleaved kininogen index (CKI),
as compared to normal controls. These data suggest a defect in hepatic synthesis as
well as increased destructive cleavage of both kininogens in plasma from patients
with cirrhosis. The decrease of important regulatory proteins like kininogens may
contribute to the imbalance in coagulation and fibrinolytic systems, which frequently
occurs in cirrhotic patients.
Keywords
High molecular weight kininogen - low molecular weight kininogen - liver cirrhosis