Tacrolimus preserves vasomotor function and maintains vascular homeostasis

Area of Science:

• Pharmacology
• Cardiovascular Research
• Immunology

Background:

• Post-transplant immunosuppression can lead to endothelial dysfunction and vasculopathy.
• Cyclosporine has been previously shown to cause vascular dysfunction.

Purpose of the Study:

• To investigate the effects of tacrolimus (Tac) on vascular function in a rat model.
• To compare tacrolimus's impact on endothelial function with that of cyclosporine.

Main Methods:

• Lewis rats received daily doses of tacrolimus (low, medium, high) or saline for two weeks.
• Thoracic aorta segments were assessed for vasorelaxation and endothelin-induced vasoconstriction.
• Receptor expression (ET(A), ET(B)), cytokine levels (TNF-α, TGF-β), plasma endothelin, and tissue oxidative injury were quantified.

Main Results:

• Tacrolimus did not impair endothelium-dependent relaxation but improved endothelium-independent vasorelaxation.
• Tacrolimus decreased sensitivity to endothelin and lowered plasma endothelin levels.
• Tacrolimus increased ET(B) receptor expression and decreased TGF-β expression, with no significant changes in oxidative injury or TNF-α.

Conclusions:

• Tacrolimus demonstrates beneficial effects on endothelial function in this rat model.
• These findings suggest tacrolimus may mitigate the vascular risks associated with immunosuppression.