Cyclosporine induces endothelial cell release of complement-activating microparticles

Area of Science:

• Nephrology
• Immunology
• Vascular Biology

Background:

• Defective complement alternative pathway control is linked to renal diseases.
• Clinical events like infections and drug use trigger atypical hemolytic uremic syndrome (aHUS) flares.
• These triggers cause cells to release microparticles, but their role in aHUS is unclear.

Purpose of the Study:

• To investigate if microparticles from injured endothelial cells activate the complement system.
• To explore the role of microparticles in cyclosporine-induced kidney injury.
• To examine microparticle changes in renal transplant patients treated with tacrolimus.

Main Methods:

• In vitro and in vivo studies using endothelial cells exposed to cyclosporine.
• Assessment of microparticle complement activation and binding of factor H.
• Analysis of plasma endothelial microparticles and C3 deposition in renal transplant patients.

Main Results:

• Cyclosporine-induced microparticles activate the alternative pathway of complement.
• These microparticles cause injury to bystander endothelial cells and renal/vascular damage in mice.
• Endothelial microparticles increased in renal transplant patients after tacrolimus initiation, with some showing C3 deposition.

Conclusions:

• Endothelial microparticles contribute to complement activation and renal disease.
• Injury-associated microparticle release is a mechanism linking systemic insults to complement-dependent kidney diseases.
• This highlights a potential therapeutic target for preventing renal complications.