Langlois M R, Delanghe J R, De Buyzere M L, Bernard D R, Ouyang J
Central Laboratory, University Hospital Gent, Belgium.
Am J Clin Nutr. 1997 Sep;66(3):606-10. doi: 10.1093/ajcn/66.3.606.
Haptoglobin is a hemoglobin-binding antioxidant showing a genetic polymorphism with three types: Hp 1-1, Hp 2-1, and Hp 2-2. The Hp 2-2 type has been associated with an increased risk of atherosclerosis. We investigated vitamin C metabolism in vivo and in vitro according to haptoglobin type in a study group of 135 healthy volunteers. Serum vitamin C concentrations were associated with haptoglobin type, showing lowest values in serum from Hp 2-2 subjects (P < 0.01). Renal threshold for L-ascorbic acid was within the normal range and metabolization to oxalate was not different among haptoglobin-type groups. Serum concentrations of other endogenous antioxidants (uric acid, bilirubin, albumin, ceruloplasmin, and total antioxidative status) were not different among haptoglobin-type groups. In vitro experiments showed a lower stability of L-ascorbic acid in blood from subjects with the Hp 2-2 type (P < 0.01). L-Ascorbic acid depletion in vitro was inversely related to haptoglobin concentration (r = -0.738). The results of this study indicate a higher rate of L-ascorbic acid oxidation in Hp 2-2 carriers because they have less protection against hemoglobin-iron driven peroxidation.
触珠蛋白是一种结合血红蛋白的抗氧化剂，具有三种类型的基因多态性：Hp 1-1、Hp 2-1和Hp 2-2。Hp 2-2型与动脉粥样硬化风险增加有关。我们在一个由135名健康志愿者组成的研究组中，根据触珠蛋白类型对体内和体外的维生素C代谢进行了研究。血清维生素C浓度与触珠蛋白类型有关，在Hp 2-2受试者的血清中显示出最低值（P < 0.01）。L-抗坏血酸的肾阈值在正常范围内，且触珠蛋白类型组之间向草酸盐的代谢没有差异。其他内源性抗氧化剂（尿酸、胆红素、白蛋白、铜蓝蛋白和总抗氧化状态）的血清浓度在触珠蛋白类型组之间没有差异。体外实验表明，Hp 2-2型受试者血液中L-抗坏血酸的稳定性较低（P < 0.01）。体外L-抗坏血酸的消耗与触珠蛋白浓度呈负相关（r = -0.738）。本研究结果表明，Hp 2-2携带者中L-抗坏血酸的氧化速率较高，因为他们对血红蛋白铁驱动的过氧化作用的保护较少。
