| |
Indinavir and Other HIV Protease Inhibitors Decrease Pneumocystis carinii In Vitro Growth C. ATZORI, E. ANGELI, F. AGOSTONI, A. MAININI, V. MICHELI, and A. CARGNEL*.
L. Sacco Hosp., Milan, Italy Background and rationale: Pneumocystis carinii pneumonia (PCP) was frequently observed among AIDS patients before the introduction of HIV protease inhibitors (PIs) in HAART treatment. The drop of PCP episodes is currently interpreted as the beneficial effect of therapy against HIV allowing immunological reconstitution, as documented by increased CD4 counts and decreased viral loads. The final demonstration that the clonal reconstitution is the only or predominant effect remains to be demostrated, since several opportunistic microorganisms like Candida, Pneumcystis and Toxoplasma own proteases which could be aspecific target of PIs and drop of cases occurred also during virologic failure. We studied PIs effect by means of an in vitro model of Pneumocystis carinii commonly used to screen experimental drugs.
Material and Methods: HEL 299 confluent monolayers maintained in multiwell plates were inoculated with P.carinii trophozoites derived from pharmacologically immunosuppressed, transtracheally infected rats. Indinavir (IDV), Ritonavir (RTV), Nelfinavir (NFV), Saquinavir (SQV) and Amprenavir (APV) were tested at concentrations clinically achievanble in vivo (20 nM to 11microM), along with maximum amount of diluents, co-trimoxazole treated (250 microg/ml) and untreated microorganisms as controls. On day 1,3,5,8 calibrated drops of supernatant were dried onto 1 cm square slide, Giemsa stained and microorganisms scored. Mean values of 30 observations/well, 4 well/drug in repeated experiments were plotted as growth curves before final evaluations.
Results and conclusion: untreated P.carinii trophozoites increased about 10 folds on day 8 and mean counts was considered 100% growth. Co-trimoxazole exerted about 88% inhibition, 100nM IDV about 60%, 130 nM RTV 46%, 100 nM NFV 40%, 100 nM SQV about 36% and 11 microM APV about 27%. Diluent and drugs did not effect uninfected monolayers. These data open intriguing implications on the possible antipneumocystis benefit of receiving PIs during HAART, out of the well known effect on HIV and immunological restoration.
Key Words: HIV, pneumocystis carinii, proteases inhibitors
|
