Modulation of Oral Candida albicans Virulence by Anti-rejection Immunosuppressors

Objective: In spite of the growing number of solid organ transplants and the increase in patient survival, fungal infections (especially  oral and systemic candidiasis) still pose a significant threat to immunocompromised patients. Modulation of Candida albicans virulence by immunosuppressive agents employed to prevent rejection of solid organ transplants remains unknown. This study aimed at evaluating whether tacrolimus, prednisolone and mycophenolate, alone and associated, simulating the triple regime usually indicated in the post transplantation period, interfere with the formation of aerobic and anaerobic biofilms of C. albicans and the secretion of aspartyl proteases (Sap).

Methods: Candida albicans SC5314 was grown in normoxia and anoxia in the presence of 440 pg.mL^-1 tacrolimus, 187 ng.mL^-1 prednisolone, and 3 μg.mL^-1 mycophenolate alone and associated at the same concentration. Negative control consisted of the C. albicans culture without the drugs. After 72 h of growth on polystyrene, aerobic/anaerobic biofilms were assessed as to their biomass and Sap secretion.

Results: In aerobic biofilms, tacrolimus and prednisolone reduced Sap secretion and the drug association also reduced biomass formation. In anaerobic biofilms, the drugs led to biomass reduction, except for prednisolone. With regard to Sap secretion, all the drugs led to a reduction of the proteolytic activity.

Conclusion: The results achieved indicate that the drugs tested led to a reduction in the virulence of C. albicans, mediated by virulence factors assessed here, suggesting that there is no increased pathogenicity.