Tissue type plasminogen activator antigen and activity in sickle cell disease

Area of Science:

• Hematology
• Vascular Biology
• Thrombosis and Hemostasis

Background:

• Sickle cell disease (SCD) is characterized by abnormal red blood cells, leading to vaso-occlusion and organ damage.
• Endothelial dysfunction and altered fibrinolysis are implicated in SCD pathophysiology.
• Tissue-type plasminogen activator (t-PA) is crucial for fibrinolysis.

Purpose of the Study:

• To investigate the hypothesis of diminished endothelial fibrinolysis in sickle cell disease.
• To assess the capacity of endothelium to synthesize and release t-PA in SCD patients.
• To determine if t-PA activity is reduced in SCD, particularly during pain crises.

Main Methods:

• Measured plasma t-PA antigen and activity in 33 SCD patients and 32 healthy controls.
• Stimulated endothelial t-PA release using venous occlusion of the arm.
• Compared t-PA levels in SCD patients during steady state and acute pain crisis.

Main Results:

• No significant differences in plasma t-PA antigen or activity were found between SCD patients and healthy controls.
• t-PA levels did not differ significantly between SCD patients in steady state versus those in acute pain crisis.
• No correlation was observed between fibrinolytic variables and the severity of microvascular occlusive disease in SCD.

Conclusions:

• The endothelium's capacity to synthesize and release t-PA is not impaired in sickle cell disease.
• Excessive inhibition of released t-PA, leading to reduced plasma activity, is not a feature of SCD.
• Fibrinolysis is likely not a primary contributor to vaso-occlusion in sickle cell disease.