Abstract
Purpose :
The proposed research aimed to obtain detailed information about the distribution of phospholipids and cholesterol between lipid domains in intact fiber-cell plasma membranes isolated from eye lenses. This information will help to better describe and understand the organizational changes in human lens fiber-cell membranes that occur with age and during cataract development.
Methods :
A new method, based on saturation-recovery (SR) electron paramagnetic resonance (EPR) spin-labeling, has been developed that allows quantitative evaluation of the amount of phospholipids and cholesterol in lipid domains of intact fiber-cell plasma membranes isolated from cortical and nuclear regions of eye lenses. This new method will complement the existing method, which is based on an analysis of conventional EPR spectra of spin labels. Both methods allowed more detailed information about the distribution of phospholipids and cholesterol between domains to be obtained.
Results :
Results confirmed that, in nuclear porcine membranes, the amounts of phospholipids and cholesterol in trapped lipid domains created due to the presence of membrane proteins were greater than those in cortical membranes. The sample-to-sample preparation/technique-related changes were evaluated for cortical and nuclear lens membranes prepared from single porcine eyes. This analysis allowed the differences of mean values, which were statistically significant with p ≤ 0.05, to be determined.
Conclusions :
Human lenses differ not only because of age, but also because of the varying health histories of the donors. Thus, single donor and/or single eye experiments are critical. It is necessary to separate health-history-related changes from preparation/technique-related changes, even for a single eye. The statistically significant differences defined for porcine lenses will be used to compare the amounts of lipids in domains in human lens membranes prepared from the eyes of single donors and from single eyes. Greater separations will indicate that differences were statistically significant (with p ≤ 0.05) and that they are due to sources other than preparation/techniques.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.