AmpB-induced renal toxicity and electrolyte losses limit treatment of fungal sepsis. Programmed cell death (apoptosis, AP) in specific renal cells may account for this phenomenon. Moreover, IGF-I prevents DNA fragmentation in injured immortalized LLCPK cells. This study determined if AmpB induces AP in renal cell lines and whether IGF-I prevents this effect. Early passages of proximal tubular cells (LLCPK), renal medullary interstitial cells (RMIC) and rat mesangial cells (ARMC) were exposed to AmpB concentrations corresponding to renal tissue levels obtained during therapy. Cell cultures were either treated with 0.5, 1.0, 2.5, 5 or 10 mcg/ml of AmpB alone for one hour or pretreated with IGF-I (50, 100mcg/ml) for 12 hours prior to AmpB exposure. Apoptotic cells were detected microscopically via in situ end labeling of DNA fragmentation (TUNEL). LLCPK and RMIC cell lines revealed dose dependent fragmentation of DNA at 0.5, 1 and 2.5 mcg/ml, while AmpB had no effect in ARMC, and led to necrosis in all three cell lines at 5 and 10 mcg/ml. LLCPK and RMIC lines pretreated with IGF-I (50, 100 mcg/ml) for 12 hours prior to exposure to AmpB had significantly fewer apoptotic nuclei. The apoptotic index(# of cells with apoptotic nuclei/# of cells counted × 100) in LLCPK and RMIC lines were as follows (mean± SEM; ANOVA with Bonferroni correction,*p < 0.05): Table Results reveal that IGF-I prevents AP induced by AmpB in LLCPK and RMIC lines in a dose dependent fashion. In conclusion, pretreatment with IGF-I may prevent AmpB-induced renal toxicity thus permitting a more efficacious use of AmpB in the treatment of fungal sepsis.

Table 1
Full size table

IGF-I kindly provided by Genetech, Inc.