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

Purpose

To compare levels of α-tocopherol in human lenses with cataract to clear human lenses and to determine associations between levels of α-tocopherol in plasma, red blood cells, and human lenses with cataract.

Design

Cross-sectional study.

Methods

Concentrations of α-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 α-tocopherol status in patients was assessed as plasma α-tocopherol (total and corrected for low-density lipoproteins) and as red blood cell bound α-tocopherol. Data (mean ± standard error of the mean) are expressed as μM α-tocopherol/g lens protein, μM α-tocopherol/l plasma, μM α-tocopherol/g low-density lipoproteins, and μM α-tocopherol/T red blood cells.

Results

Concentrations of α-tocopherol were measured in 27 lenses of cataract patients, 8 cadaver lenses with cataract and in 14 clear cadaver lenses. The concentration of α-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 α-tocopherol or red blood cell bound α-tocopherol and lens α-tocopherol in patients.

Conclusions

Serum and red blood cell levels of α-tocopherol may not reflect the α-tocopherol status of the lens itself and therefore may not be clinically relevant markers for cataract risk. Mechanisms leading to increased levels of α-tocopherol in cataract lenses need to be explored in future research.