LIPOFUSCIN IN THE RETINA - QUANTITATIVE ASSAY FOR AN UNPRECEDENTED AUTOFLUORESCENT COMPOUND (PYRIDINIUM BIS-RETINOID, A2-E) OF OCULAR AGE PIGMENT

The pyridinium bis-retinoid, A2-E, has been discovered as one of the m ajor autofluorescent components of retinal pigment epithelial lipofusc in. Due to its chemical characteristics, A2-E may contribute to cellul ar and molecular changes leading to age-related macular degeneration. Because A2-E is the first lipofuscin component that has been identifie d, purified, and its structure analysed, it represents an important ma rker molecule for studying lipofuscin formation under various conditio ns. In order to investigate the role of A2-E in ageing processes of th e retinal pigment epithelium, we developed an HPLC assay for this comp ound using single wavelength UV-absorbance detection with continuous l ight emission. Standard A2-E was synthetized and purified by sequentia l TLC. In our assay, A2-E can be detected in amounts lower than 10 pmo l. The assay has been applied to quantitative determination of A2-E am ounts in albino rat eyes of different age groups. Our results demonstr ate that there is a marked increase of A2-E levels in older animals. T he method described is the first to allow quantification of this unusu al retinoid from small amounts of biological samples. (C) 1997 Academi c Press Limited.