Abstract
Purpose:
Previous studies of our research group have shown that ApoA-I mimetic peptides like D-4F and L-4F are able to reduce pathological lipid deposits in and on top of Bruch’s membrane (Rudolf et al. ARVO 2011, 2013). Since the function of the retinal pigment epithelium (RPE) plays a central role in photoreceptor health and function we evaluate the effect of these peptides on RPE cell viability in vitro.
Methods:
Third passage porcine RPE cell cultures were treated with different concentrations of L-4F or its stereoisomer D-4F (0; 0.1; 10; 100; 500; 1000; 2000; 4000 µg/ml) for 48 hrs. Nonfunctional scrambled L-4F (sL-4F) served as a control. MTT assays (Dimethylthiazol diphenyltetrazolium bromide) were performed to analyse the peptides’ cytotoxicity on RPE cells. RPE cell proliferation activity was assessed by measuring the optical density at 577 nm using a photometric multiplate reader. Further test runs were performed in smaller concentration steps to detect the maximum tolerated dose of these peptides.
Results:
D-4F and L-4F showed no significant effect in MTT assays with concentration ≤ 10 µg/ml. With higher concentrations, L-4F ≤ 375 µg/ml and ≤ 125 µg/ml for D-4F induced a significant increase of optical density (p<0.01). L-4F concentrations ≥ 500 µg/ml reduced significantly RPE cell proliferation (p<0.01). The same effect was detected for D-4F at concentrations ≥ 250 µg/ml. The control peptide sL-4F did not show any significant difference on RPE cell proliferation activity.
Conclusions:
Our results demonstrated cytotoxic effects in RPE cell culture if exposed to concentrations of L-4F ≥500 µg/ml and ≥ 250 µg/ml of D-4F. In RPE cell cultures concentrations up to 10 µg/ml can be considered safe for both peptides. Additional tests are needed to explain sufficiently the increase of optical density for concentrations between 10 µg/ml and the mentioned toxicity levels above.
Keywords: 412 age-related macular degeneration •
701 retinal pigment epithelium •
503 drug toxicity/drug effects