Forms of PAI:
(1) PAI type 1: usual form
(2) PAI type 2: usually not detectable; may be elevated in pregnant women
|
PAI Concentration
|
Effect on Fibrinolysis
|
Clinical Effect
|
|
increased
|
decreased
|
thrombosis
|
|
decreased
|
increased
|
bleeding
|
The plasma concentration of PAI is affected by:
(1) daily circadian rhythm (low in evening, high in morning)
(2) acute phase reaction to thrombosis (transiently increased)
(3) pregnancy (increased due to presence of PAI-2)
(4) genotype (increased with 4G allele, see below)
(5) presence of antifibrinolytic agents (if tested by functional assays)
(6) insulin resistance (increased levels)
The genotype of PAI affects the plasma level and the risk of thrombosis.
|
Genotype
|
Thrombosis Risk
|
|
5G/5G
|
none
|
|
4G/5G
|
minimal to mild
|
|
4G/4G
|
mild to moderate
|
The presence of either 4G/5G or 4G/4G genotype plus prothrombin G20210A was associated with increased risk of venous thrombosis (Barcellona et al).
