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VOL 66 (4) 2000 IN VITRO INDUCTION OF APOPTOSIS BY CYCLOSPORINE A

inhibió la activación de caspasa-3 y atenuó la apoptosis inducida por CsA y la pérdida de
LDH. El inhibidor de caspasa-6, Ac-VEID-CHO, únicamente inhibió la apoptosis
inducida por CsA. El descenso de potencial de membrana mitocondrial y la liberación de
citocromo C fueron paralelos a los cambios de ultraestructuras mitocondriales y pudieran
considerarse reacciones tempranas que desencadenan la cascada de fenómenos
apoptóticos. La microscopia de transmisión electrónica (TEM) confirmó el incremento
del número de células necróticas al cabo de 20 horas, pero no tras 4 horas de incubación,
en comparación con los controles.

Palabras clave: Apoptosis.-. Ciclosporina A.- Potencial de membrana mitocondrial.-
Caspasas.- Fragmentación de ADN.-

INTRODUCTION

Over the last 20 years, the immunosuppressive drug, CsA, has
revolutionized organ transplantation by preventing graft rejection of
different organs, and has been successfully used in the treatment of
autoimmune disease. In cancer therapy, CsA-related compounds are
successfully used in the reversion of multidrug resistance by inhibiting
the p-gp 170-kDa protein (Advani et al. 1999). Its successful clinical
application is accompanied, however, by side effects in the liver (Kahan
1993, Rush 1991). Clinically, CsA-induced hepatic effects are mainly of a
cholestatic nature, which manifests itself by elevated serum bile-acid
levels (Schade et al. 1983), together with hyperbilirubinemia (Soresi et al.
1995). In rat hepatocytes, CsA inhibited the uptake and secretion of bile
acids, and bile flow in the isolated perfused rat liver (Wolf et al. 1998,
Kiefer et al. 1997). In addition to cholestasis, an increase in serum
aminotransferase activity has been observed in some clinical studies with
CsA, but this has been found more frequently after treatment with its O-
hydroxyethyl-D-(Ser)8-cyclosporine derivative, SDZ IMM125 (Wolf et
al. 1998). In rats, serum aminotransferase activity increased only after
treatment at very high dosages (Donatsch et al. 1992). In hepatocyte
primary cultures and in the isolated perfused liver, CsA caused the release
of lactate dehydrogenase, which correlated very well with that of serum
transaminases (Wolf et al. 1998, Wolf et al. 1997). The leakage of liver-
specific aminotransferases into the serum might be regarded as the result

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