Yeum K J, Shang F M, Schalch W M, Russell R M, Taylor A
Tufts University, Jean Mayer United States Department ofAgriculture Human Nutrition Research Center onAging at Tufts University, Boston, M A 0211, USA.
Curr Eye Res. 1999 Dec;19(6):502-5. doi: 10.1076/ceyr.19.6.502.5282.
Recent epidemiologic studies suggest that differential risk for cataract in different areas of the lens may be related to intake of carotenoids, retinol, and tocopherol. Nevertheless, there is little information about differential localization of these nutrients in the lens. To determine the spatial distribution of fat-soluble nutrients within the lens, we determined levels of these nutrients in the epithelium/ outer cortex vs. inner cortex/nucleus.
Concentrations of carotenoids, retinol, and tocopherol were determined in the epithelial/cortical (younger, more metabolically active tissue) and nuclear (older, less metabolically active) layers of human cataractous lenses (n = 7, 64-75 yr) by reverse-phase high-performance liquid chromatography (HPLC).
Lutein/zeaxanthin was the only carotenoid, which was detected, in human lens. Consistent with prior reports, no beta-carotene or lycopene were detected. Concentrations of lutein/zeaxanthin, tocopherol, and retinol in epithelium/cortex tissue were approximately 3-, 1.8-, and 1.3-fold higher than in the older lens tissue. Specifically, the epithelial/cortical lens layer, comprising about half of the tissue, contains 74% of lutein/zeaxanthin (44 ng/g wet wt), 65% of alpha-tocopherol (2227 ng/g wet wt), and 60% of retinol (30 ng/g wet wt).
The data suggest that upon development and aging, there is differential localization of these nutrients. The data are also consistent with a protective role of these nutrients against oxidative damage in the epithelium and cortex of the human lens.
近期的流行病学研究表明，晶状体不同区域患白内障的风险差异可能与类胡萝卜素、视黄醇和生育酚的摄入量有关。然而，关于这些营养素在晶状体中的差异定位信息很少。为了确定脂溶性营养素在晶状体内的空间分布，我们测定了这些营养素在上皮/外皮质与内皮质/核中的水平。
通过反相高效液相色谱法（HPLC）测定了7例年龄在64 - 75岁的人类白内障晶状体上皮/皮质（较年轻、代谢更活跃的组织）和核（较年长、代谢较不活跃）层中类胡萝卜素、视黄醇和生育酚的浓度。
叶黄素/玉米黄质是在人晶状体中检测到的唯一类胡萝卜素。与先前报道一致，未检测到β - 胡萝卜素或番茄红素。上皮/皮质组织中叶黄素/玉米黄质、生育酚和视黄醇的浓度分别比老年晶状体组织高约3倍、1.8倍和1.3倍。具体而言，占组织约一半的上皮/皮质晶状体层含有74%的叶黄素/玉米黄质（44 ng/g湿重）、65%的α - 生育酚（2227 ng/g湿重）和60%的视黄醇（30 ng/g湿重）。
数据表明随着发育和衰老，这些营养素存在差异定位。这些数据也与这些营养素对人类晶状体上皮和皮质氧化损伤的保护作用一致。
