維生素C及紅血球生成素對HepG2細胞表現Hepcidin與紅血球生成素受器的影響

The expression of hepcidin and erythropoietin receptor are affected by Vitamin C and Erythropoietin in HepG2 cell

邱炳芳(Ping-Fanf Chiu)

指導教授 ： 柯順耀

共同指導教授 ： 張以正

長榮大學/健康科學學院/醫學研究所/碩士(2009年)

https://doi.org/10.6833/CJCU.2009.00066

摘要

Hepcidin是最近發現從肝細胞所分泌的蛋白質，負責十二指腸對鐵的吸收和reticuloendothelial系統巨噬細胞內鐵的釋放。在腎衰竭患者中已經被證實血漿中hepcidin越高貧血越嚴重。臨床實用顯示，在功能（相對）性缺鐵的腎衰竭患者中，高劑量erythropoietin （EPO）和Vitamin C能改善部分貧血。但是EPO相當昂貴且使用劑量也有最大的限制。 研究已證實在HepG2細胞中，EPO可以調節hepcidin的表現。而臨床上Vitamin C改善部分貧血的機制尚未清楚。因此，本研究假設Vitamin C可能影響hepcidin表現。研究使用HepG2 處理不同濃度Vitamin C （0- 100 ug/ml）及紅血球生成素EPO-?? （0- 1.0 U/ml），於37℃處理細胞6小時。使用RT-PCR及real-time PCR分析hepcidin, EPO, EPO-R 的mRNA表現量。結果顯示EPO和Vitamin C皆會直接抑制HepG2細胞表現hepcidin。另外EPO會抑制EPO-R的表現。有趣的是，Vitamin C會增加EPO-R的表現量，但不會影響EPO的表現。本研究的結果顯示Vitamin C會抑制hepcidin表現，其中一個可能方式是藉由增加EPO-R的量，進而提升EPO的作用，而不是直接調控EPO所產生的結果。本實驗提供一個臨床治療上有力的證據，可以解釋為何EPO加入Vitamin C能改善功能（相對）性缺鐵的腎衰竭患者貧血，及提供一個可能路徑－是經由Vitamin C會增加紅血球生成素受器的表現。

關鍵字

維生素C ； 紅血球生成素 ； Hepcidin ； 腎性貧血

並列摘要

The hepcidin, newly found protein secreted by hepatic cell, modulate the de novo iron absorbed from duodenum and the recycled iron released from reticuloendothelial system. Uremia patients with higher serum hepcidin level is proved as in more severe anemic state. The administration of higher erythropoietin (EPO) dose or Vitamin C enable to correct those functional iron deficiency. But EPO is very expensive and limited dosage . The EPO regulated hepcidin expression within HepG2 cell and murine hepatocyte is identified by Pinto et al. recently. However, the mechanism of Vitamin C to improve anemia is still unknown. That study is supposed that Vitamin C may regulate hepcidin expression as EPO. HepG2 cell was cultured with Vitamin C (0-100 ?慊/ml ) and EPO (0-1.0 U/ml) separately for 6 hours at 37℃. Reverse transcription polymerase chain reaction and real time PCR were to measure hepcidn , EPO and EPO-R expressions. The result reveals that EPO can inhibit the hepcidin expression within HepG2 cell in dose-dependency. Besides, Erythropoietin will down-regulate its receptor in HepG2 cell early. Moreover, It is excitedly that Vitamin C is found to enhance the EPO-R expression. Vitamin C has little effect on EPO expression. That may be account for and offer one mechanism of Vitamin C to improve the anemia is mediated by its enhanced expression of EPO-R, that reduces the production of hepcidin eventually. Those result will offer power of Vitamin C for anemia care.

並列關鍵字

Vitamin C ； Erythropoietin ； Hepcidin ； renal anemia

參考文獻

Andrews NC. 2004. Anemia of inflammation: the cytokine -hepcidin link. J Clin Invest 113(9):1251-1253.

Anupama Mohanram, Zhongxin Zhang, Shahnaz Shahinfar. 2004. Anemia and end-stage renal disease in patients with type 2

diabetes and nephropathy. Kidney International 66:1131–1138

Camaschella C. 2005. Understanding iron homeostasis through genetic analysis of hemochromatosis and related disorders. Blood 106(12):3710-3717.

Caterina Canavese, Michele Petrarulo, Paola Massarenti. 2005. Long-term, low-dose, intravenous vitamin C leads to plasma calcium oxalate supersaturation in hemodialysis patients. American Journal of Kidney Diseases. 45: 540-549