Abstract
Purpose:
Lutein and zeaxanthin, the two principal dietary carotenoids in the human eye, can play a protective role against human ocular diseases such as age-related macular degeneration (AMD) and cataract; however, these carotenoids are lipophilic compounds with relatively low oral bioavailability in mouse models of eye disease. In this study, we evaluated the absorption and bioavailability of various zeaxanthin formulations including aqueous nanodispersions of zeaxanthin with sucrose monolaurate (SML) or Captisol versus DSM ActiLease zeaxanthin beadlets incorporated into the chow. Our ultimate goal was to develop an optimized formulation for reliable uptake of carotenoids into mouse tissues including the eye.
Methods:
C57BL/6 mice, (13-15 weeks) were used in this study. The experimental groups (5 each) received zeaxanthin-Captisol (12.5 mg/per day/mouse) by daily gavage, zeaxanthin- SML (0.140 mg/per day/mouse) in drinking water or DSM ActiLease zeaxanthin beadlet chow (1g/kg) for 4 weeks. The control group (3 wild type mice) received Captisol, SML, or the placebo beadlets alone. The tissues were harvested after 4 weeks of feeding, and the samples were analyzed using HPLC.
Results:
Control mice had barely detectable lutein and zeaxanthin in serum, liver, and none in the eye. With supplementation, we could achieve serum levels 1/10 of normal human serum, and liver levels increased substantially in both the Captisol and SML groups, but no carotenoids were detected in the eye tissues. In the beadlet chow group, a 10 fold increase in absorption was detected in serum and liver tissues compared with other delivery methods. Trace amounts of carotenoids wer present in the RPE tissues (1 ng/pair).
Conclusions:
DSM ActiLease zeaxanthin beadlets could deliver carotenoids to mice at a level comparable to the physiological level found in adult human serum . This improved delivery protocol could serve as a useful method to study the function of lutein and zeaxanthin in the retina of various transgenic mouse lines designed to have enhanced retinal carotenoid uptake relative to wild-type mice.
Keywords: 412 age-related macular degeneration •
444 carotenoids/carotenoid binding proteins •
587 macular pigment