Abstract
Purpose :
Curcumin, a diarylheptanoid isolated from turmeric, is a useful naturally fluorescent probe for the in vivo visualization of β-amyloid (βA). βA is found in macular drusen, which are the hallmark of eyes affected with age-related macular degeneration (AMD). The purpose of this study is to determine and quantitate the time course of curcumin fluorescent labeling of drusen.
Methods :
Twelve intermediate stage AMD patients were enrolled from Zaparackas and Knepper, Ltd. Each patient received curcumin (1330 mg BID) for six months. Retinal images were acquired using Heidelberg Spectralis OCT at five time points: baseline, one week after start of curcumin, two, four, and six months. All procedures were approved by the Quorum IRB (Seattle, WA). Individual drusen were identified, segmented, thresholded, and analyzed at each time point using ImageJ software. Two methods were used to measure drusen: an interactive cursor outline and a spot analysis (fluorescence fold change mean=0.901, SD=0.389; mean=0.936, SD=0.390), of which spot analysis was chosen to determine fluorescence. Drusen <63 µm were not fluorescent. Background was subtracted using baseline fluorescence levels and fold change was measured. Two-tailed student’s t-test was used for statistical analysis.
Results :
Average fluorescence was significantly increased in all macular regions in patients at one week (mean=17.1±4.0, p=0.02), two months (mean=29.2± 6.7, p=0.03), and four months (mean=33.7± 7.0, p=0.01) compared with baseline. Fluorescence was also increased at six months (mean=21.0±6.5). Area of thresholded fluorescent spots was also significantly increased at one week (mean=294.1± 262,8, p=0.02), two months (mean=1000.6±331.6, p=0.007), four months (mean=1093.6±371.1, p=0.008), and six months (mean=284.0±109.2, p=0.03). Individually, patients demonstrated increased curcumin fluorescence in foveal drusen at two (n=10), four (n=7), and six months (n=5).
Conclusions :
Curcumin-labeled βA is useful to follow changes in drusen fluorescence over time. The observation of an increase in fluorescence followed by a decrease suggests the disappearance of βA in drusen. βA may act as a nidus for the accumulation of drusen proteins and lipids. The uptake of curcumin into drusen mitigates the notion that curcumin has low bioavailability and, in fact, curcumin is retained in drusen. Therefore, curcumin may be useful in monitoring drusen progression, as well as progression to late forms of AMD.
This is a 2020 ARVO Annual Meeting abstract.