Influence of lipoproteins on renal cytotoxicity and antifungal activity of amphotericin B.
We examined the influence of high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs) on the toxicity of amphotericin B (AmpB) to fungal and renal cells. Candida albicans was incubated for 18 h at 37 degrees C with AmpB and deoxycholate (Fungizone) or liposomal AmpB (L-AmpB) (0.1 to 2.0 micrograms of AmpB per ml) in the presence or absence of HDLs or LDLs (0.5 mg of protein per ml). The MICs of AmpB and L-AmpB, whether or not HDLs or LDLs were present, were similar. LLC PK1 renal cells, derived from primary cultures of pig proximal tubular cells, were incubated for 18 h at 37 degrees C in serum-free medium that contained AmpB and deoxycholate or L-AmpB at 20 micrograms of AmpB per ml, HDLs or LDLs at 0.5 mg of protein per ml, mixtures of AmpB with HDLs or LDLs, and mixtures of L-AmpB with HDLs or LDLs. HDL-associated AmpB was less toxic than AmB to LLC PK1 cells (53.0% +/- 2.5% versus 81.3% +/- 3.6% cytotoxicity; P = 0.01), while LDL-associated AmpB was as toxic as AmpB. L-AmpB, HDL-associated L-AmpB, and LDL-associated L-AmpB were less toxic to LLC PK1 cells than was AmpB (48.3% +/- 1.5%, 25.5% +/- 2.2%, and 52.2% +/- 2.5% versus 81.3% +/- 3.6% cytotoxicity; P = 0.02). To further understand why HDL-associated AmpB reduced renal cytotoxic effects, the LLC PK1 cells were examined for the presence of HDL and LDL receptors. LLC PK1 cells expressed high-affinity (K(d) = 0.0538 nanograms/ml; 96,000 sites per cell) and low-affinity (K(d) = 222.22 nanograms/ml; 77 sites per cell) LDL receptors but only a low-affinity HDL receptor (K(d) = 71.43 nanograms/ml; 2 sites per cell). HDL-associated AmpB and LDL-associated AmpB were less toxic than AmpB to trypsinized LLC PK1 cells (46.6% +/- 10.9% and 16.8% +/- 15.98% versus 74.7% +/- 7.7% cytotoxicity; P = 0.02). HDL-associated AmB and LDL-associated L-AmpB were also less toxic than AmpB to the cells (20.4% +/- 6.2% and 13.5% +/- 8.6% versus 74.7% cytotoxicity; P = 0.01). The antifungal activities of AmpB and L-AmpB were not altered in the presence of HDLs or LDLs. We conclude that the reduced nephrotoxicity associated with the use of L-AmpB is related to a decreased uptake of AmpB by renal cells when AmpB is associated with HDLs because of the low level of expression of HDL receptors in these cells.
Wasan
K M
KM
Department of Clinical Investigation, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Rosenblum
M G
MG
Cheung
L
L
Lopez-Berestein
G
G
D000666:Amphotericin B / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity*; D000818:Animals; D002176:Candida albicans / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007674:Kidney Diseases / Q000139:chemically induced*; D008075:Lipoproteins, HDL / Q000097:blood / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000097:blood / Q000502:physiology*; D008081:Liposomes; D011973:Receptors, LDL / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D018110:Receptors, Lipoprotein / Q000032:analysis / Q000378:metabolism; D013552:Swine
D004337:Drug Carriers; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008081:Liposomes; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; C064018:apolipoprotein A-I A-II receptor; D000666:Amphotericin B