Abstract
Purpose :
Long-term usage of hydroxychloroquine (HCQ) for the treatment of autoimmune diseases often leads to HCQ retinopathy. This is caused mainly by the inhibition of lysosomal enzyme activity, which leads to the blockage of autophagy, resulting in an increase in vacuolation and cell death. We established an in vitro model using cultured human RPE cells to evaluate the effects of various factors on the protection of RPE cells against HCQ toxicity and tested the effects of basic fibroblast growth factor (bFGF) on this process.
Methods :
ARPE 19 cell line and a primary cell culture of human RPE cells were seeded into 12-well and 96-well plates and treated with HCQ at 10 -100 μM with or without bFGF (10 ng/ml) for 3 days. Morphological changes and cell viability were evaluated using phase-contrast microscopy and MTT studies. All experiments were performed in triplicate.
Results :
RPE cells cultured with 30 μM HCQ showed a marked increase of vacuolation in the cytoplasm, without changes of cell viability. Cells cultured with 100 μM HCQ showed a significant decrease in cell viability to 16%±2% of the control (P<0.05). bFGF did not affect the accumulation of vacuolation in cells treated with 30 μM HCQ, but significantly increased the viability of cells treated with 100 μM HCQ alone (4.3 fold) (P<0.05). However, the number of viable cells was still less than cells not treated with HCQ (69 ±8% of the control, P<0.05), suggesting that bFGF has a significant but only partial protective effect on HCQ-induced cell death.
Conclusions :
HCQ-induced RPE cells damage can be evaluated using this in vitro model. bFGF partially improves cell viability of RPE cells treated by HCQ, but does not reduce the accumulation of vacuolation. This suggests that bFGF cannot restore the function of the lysosomes and that the decrease of cell death is possibly a non-specific cell survival effect. Further exploration of potential agents which can recover lysosomal enzyme activity and restore autophagy will be necessary in order to develop a novel therapy for HCQ retinopathy.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.