Differences and Compatibility between Human and Porcine Fibrinolytic Components toward Plasmin Generation and Fibrin...

Area of Science:

• Biochemistry
• Comparative physiology

Background:

• Fibrinolysis, the breakdown of blood clots by plasmin, is crucial in hemostasis.
• Large animals like pigs are increasingly used in disease models, necessitating comparison of their fibrinolytic systems with humans.

Purpose of the Study:

• To directly compare and characterize structural and functional differences between human and porcine fibrinolytic factors.
• To elucidate species-specific variations in plasmin generation and fibrinolysis.

Main Methods:

• Investigated plasmin generation using permutations of human/porcine plasminogen, tissue-type plasminogen activator (tPA), and fibrinogen.
• Assessed fibrin breakdown by human/porcine plasmin on human/porcine fibrin using turbidity assays and SDS-PAGE.
• Compared primary structures of key fibrinolytic proteins.

Main Results:

• All-human components yielded 24-fold higher plasmin generation than all-porcine components.
• Human fibrin presence increased plasmin generation 2- to 34-fold compared to porcine fibrin.
• Porcine plasmin exhibited higher catalytic efficiency (kcat) for both human (2.7-fold) and porcine (6.7-fold) fibrin breakdown.
• Sequence analysis revealed significant differences in fibrin-binding domains of plasminogen (Kringle 1) and tPA (Kringle 2), and in the αC domain of fibrinogen.

Conclusions:

• The human and porcine fibrinolytic systems exhibit notable species-specific differences.
• These variations significantly impact plasmin generation and the efficiency of fibrin clot breakdown.