Factor-VIII activity and antigen, platelet count and biochemical changes after adrenoceptor stimulation

Area of Science:

• Pharmacology
• Hematology

Background:

• The study investigates the effects of sympathomimetic amines on hemostasis and biochemical parameters.
• Understanding these effects is crucial for managing patients undergoing procedures or experiencing conditions involving these agents.

Purpose of the Study:

• To compare the impact of adrenaline, isoprenaline, and salbutamol on coagulation factors, platelet count, and metabolic markers.
• To elucidate the mechanisms behind observed changes, particularly the rise in factor VIII.

Main Methods:

• Intravenous administration of adrenaline, isoprenaline, and salbutamol to human subjects.
• Monitoring of pulse rate, blood pressure, and blood levels of coagulation factors (V, VIII, X, XI, XII), platelet count, lactate, pyruvate, potassium, and free fatty acids.
• Detailed analysis of factor VIII using clotting assays, antibody reactions, and chromatography.

Main Results:

• Adrenaline, isoprenaline, and salbutamol increased pulse rate; adrenaline caused a ~2.5-fold rise in factor VIII, while isoprenaline and salbutamol caused a ~1.5-fold rise.
• Platelet count increased with adrenaline, decreased with salbutamol, and remained unchanged with isoprenaline.
• Lactate levels rose with adrenaline and salbutamol but not isoprenaline; other clotting factors and factor VIII molecular size did not significantly change.

Conclusions:

• The rise in factor VIII activity with adrenaline is likely a true increase in concentration, possibly mediated by a beta2 effect releasing factor VIII from stores.
• The platelet count changes suggest a combination of alpha-mediated splenic contraction and beta2-mediated effects.
• The quantity of releasable factor VIII appears independent of current plasma levels.