Taurine uptake by human retinal pigment epithelium: Implications for the transport of small solutes between the choroid and the outer retina
Taurine uptake by human retinal pigment epithelium: Implications for the transport of small solutes between the choroid and the outer retina
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DOI：
10.1167/iovs.04-0919
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发表时间：
2004-12-01
影响因子：
4.4
通讯作者：
Marshall, J
中科院分区：
文献类型：
--
作者：
Hillenkamp, J;Hussain, AA;Marshall, J
目的。表征从人类供体眼睛中新鲜分离的视网膜色素上皮 (RPE) 中牛磺酸转运蛋白 (TT) 的米氏动力学。目的 确定人类老年组中由布鲁赫脉络膜 (BC) 和 RPE 组成的牛磺酸从脉络膜血供至外视网膜输送途径中的限速室。方法。在人类供体样本（4 只受黑色素瘤影响的眼睛和 14 只对照眼睛；年龄范围，62-93 岁）中，使用放射化学技术测定不同外源浓度下的 RPE 牛磺酸积累。人 RPE 的转运能力是通过对底物浓度为 1 至 60 muM 牛磺酸的高亲和力载体进行动力学分析获得的。 结果。人 RPE 中牛磺酸浓度为 1 muM 的牛磺酸摄取与供体年龄无关 (P > 0.05)，平均为每 6 毫米环钻 2.83 +/- 0.27 (SEM) pmol/10 分钟。人 RPE 的牛磺酸转运是由每 5 毫米圆盘 K-m 50 muM 和 V-max 267 pmol/10 分钟的高亲和力载体介导的。结论。在人类捐赠者的 RPE 中，牛磺酸的摄取在 62 至 93 岁的年龄范围内仍然可行。 RPE 中的牛磺酸转运速率低于孤立的 BC 复合体中的牛磺酸转运速率，因此数据表明，前室包含牛磺酸向外视网膜输送的限速步骤。
PURPOSE. To characterize the Michaelis-Menten kinetics of the taurine transporter ( TT) in retinal pigment epithelium (RPE) freshly isolated from human donor eyes. To identify the rate limiting compartment in the pathway of taurine delivery from the choroidal blood supply to the outer retina composed by Bruch's-choroid ( BC) and the RPE in the human older age group.METHODS. In human donor samples (4 melanoma-affected eyes, and 14 control eyes; age range, 62-93 years), radiochemical techniques were used to determine the RPE taurine accumulation at various exogenous concentrations. The transport capability of human RPE was obtained from a kinetic analysis of the high-affinity carrier over a substrate concentration of 1 to 60 muM taurine.RESULTS. Uptake of taurine into human RPE at a taurine concentration of 1 muM was independent of donor age (P > 0.05) and averaged at 2.83 +/- 0.27 (SEM) pmol/10 minutes per 6-mm trephine. Taurine transport by human RPE was mediated by a high-affinity carrier of K-m 50 muM and V-max of 267 pmol/10 minutes per 5-mm disc.CONCLUSIONS. In human donor RPE, uptake of taurine remained viable in the age range 62 to 93 years. Taurine transport rates in the RPE were lower than across the isolated BC complex, and thus the data suggest that the former compartment houses the rate-limiting step in the delivery of taurine to the outer retina.