Fig. 1

Phagocytosis level in RPE from human eyes of donors of different ages. RPE cells were isolated from eyes of 6 normal donors (no significant ocular medical history) with age 31, 39, 59, 61, 71 and 79, and 4 AMD donors with age 65, 84, 86, and 88 and cultured as described in “Methods”. For phagocytosis assay, 5 × 10⁴ human RPE cells were plated in a 24-well plate, maintained in MEM containing 20% (v/v) FBS for at least 6 days, then in MEM with 5% FBS (v/v) before the assay. Circle shown for normal age 31 represents 10 counted numbers of internalized OS from 10 representative fields from one experiment. The circles for all the other age groups represent counted numbers of internalized OS from 10 representative fields per experiment from three independent experiments for each age group. A moderate negative (a) and weak negative (b) correlation between phagocytosis level and age was shown in the normal and AMD RPE, respectively