LAUSR

INTRODUCTION The accumulation of lipofuscin is a hallmark in the pathogenesis of Stargardt disease (STGD1) and geographic atrophy (GA) secondary to age-related macular degeneration (AMD). Limiting lipofuscin accumulation by inhibiting the retinol binding protein 4 (RBP4) is being explored as a potential treatment target for those diseases. In this study, we aimed to establish the concentration of RBP4 in the systemic circulation in different age cohorts of healthy individuals and to check if patients with STGD1 or GA may show abnormal RBP4 levels. METHODS 40 healthy subjects of various age groups, 15 Stargardt patients and 15 GA patients were included in the study. We measured RBP4 levels, serum retinol (SR) levels, complete blood count (CBC), and blood chemistry including liver function tests. RESULTS Mean RBP4 for all cohorts was 26'911.40 ± 6'198.61 ng/mL and mean SR 1.75 ± 0.36 µmol/L. Age was not found to significantly impact levels neither of RBP4 and SR nor of the RBP4-to-SR ratio. Also, the two patient groups showed similar blood levels to their age-matched controls. DISCUSSION/CONCLUSION Serum RBP4 and SR do not appear to be affected by age in healthy individuals and remain within normal limits in both STGD1 and GA.