Alpha-tocopherol in plasma, red blood cells and lenses with and without cataract

PURPOSE: To compare levels of alpha-tocopherol in human lenses with cataract to clear human lenses and to determine associations between levels of alpha-tocopherol in plasma, red blood cells, and human lenses with cataract. DESIGN: Cross-sectional study. METHODS. Concentrations of et-tocopherol were measured by high-performance liquid chromatography in blood and in human lenses with and without cataract. Lenses were obtained during cataract surgery and from a regional eye bank. Peripheral alpha-tocopherol status in patients was assessed as plasma alpha-tocopherol (total and corrected for low,density lipoproteins) and as red blood cell bound alpha-tocopherol. Data (mean - standard error of the mean) are expressed as muM alpha-tocopherol/g lens protein, muM alpha-to, copherol/l plasma, muM alpha-tocopherol/g low-density lipoproteins, and muM alpha-tocopherol/T red blood cells. RESULTS: Concentrations of alpha-tocopherol were measured in 27 lenses of cataract patients, 8 cadaver lenses with cataract and in 14 clear cadaver lenses. The concentration of alpha-tocopherol was significantly higher in cataract than in control cadaver lenses (0.49 +/- 0.04 vs 0.35 +/- 0.03, P <.05). The difference between α-tocopherol in lenses of cataract patients and control cadaver lenses was even higher (0.7 +/- 0.1 vs 0.35 +/- 0.03, P <.01). No significant correlation was observed between plasma alpha-tocopherol or red blood cell bound alpha-tocopherol and lens alpha-tocopherol in patients. CONCLUSIONS: Serum and red blood cell levels of alpha-tocopherol may not reflect the alpha-tocopherol status of the lens itself and therefore may not be clinically relevant markers for cataract risk. Mechanisms leading to increased levels of a,tocopherol in cataract lenses need to be explored in future research.