Age-dependent structural changes in intact human lenses detected by synchrotron radiation x-ray scattering: Correlation with maillard reaction protein fluorescence

To understand alterations in the spatial organization of the crystallins, the major determinant of lens transparency, the x-ray scattering by intact normal human lenses from individuals 6-82 years of age was measured using synchrotron radiation. The angular dependence of the integrated scattering intensity is consistent with short-range order within the crystallin assemblies. A significant change in the scattering patterns of the lenses occurs after 55 years of age, in parallel with an increase of the fluorescence of the urea-insoluble crystallin fraction. This correlation suggests a gradual derangement of the short-range order as a result of cross-linking of the crystallin subunits by advanced Maillard reaction products that are generated by the continuous reaction of sugars, such as glucose or fructose, with proteins.