臓器移植患者のMDR1及びCYP3A遺伝子情報に基づく個別免疫抑制療法の確立

• Project/Area Number: 15689010
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Applied pharmacology
• Research Institution: Kyoto University
• Principal Investigator: 増田 智先 京都大学, 医学研究科, 講師 (90303825)
• Project Period (FY): 2003 – 2005
• Project Status: Completed (Fiscal Year 2005)
• Budget Amount: ¥25,610,000 (Direct Cost: ¥19,700,000、Indirect Cost: ¥5,910,000); Fiscal Year 2005: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000); Fiscal Year 2004: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000); Fiscal Year 2003: ¥12,350,000 (Direct Cost: ¥9,500,000、Indirect Cost: ¥2,850,000)
• Keywords: P-糖タンパク質 / トランスポータ / 生体肝移植 / タクロリムス / 免疫抑制剤 / CYP3A4 / 白血球 / 吸収障壁 / P-糖蛋白質

Research Abstract

臓器移植治療におけるタクロリムスなどを中心とした免疫抑制療法は、移植片生着のためには必須とされる。一方、タクロリムスの血中濃度を有効域に保っているにも関わらず、急性拒絶反応や、過剰な免疫抑制によると感染症の合併などが問題となっているため、タクロリムスに対する応答性(薬物感受性)の個別化が必要と考えられる。さらに、正確な薬物治療の指標となるバイオマーカーの特定が望まれている。
本研究では、免疫抑制剤の薬効発現部位である末梢血白血球に着目し、生体肝移植直後の拒絶反応の発現をエンドポイントとして、術後3、7、14日目の抹消血検体よりtotal RNAを抽出し、様々な遺伝子発現について検討した結果、ステロイド薬の標的分子であるグルココルチコイド受容体(GR/NR3Cl)の発現量には、大きな個体間変動が存在すること、機能欠損型バリアントであるGRβはほとんど発現せず臨床的役割は小さいこと、GRのシャペロンとして機能するFKBP4または5の発現量に大きな個体間変動は認められないことなどが明確となり、ステロイド薬に対する感受性の個人差の分子機序解明につながる成果を得た。
次に、肝移植直後の急性拒絶反応とタクロリムス血中濃度とを比較した結果、術直後4日間の血中濃度を十分に保たなければ拒絶反応発現の危険性が高いことが認められた。さらに、小腸MDR1 mRNAレベルはタクロリムス初期血中濃度推移に強く影響を与えるのみならず、拒絶反応発現と未設に関連するバイオマーカーであることが判明した。パイロット的に行った、術時小腸MDR1 mRNAレベルを参考にしたタクロリムスの初期用量設定法は、拒絶反応の縮減と良好な患者予後に貢献した。
以上、本研究では小腸のMDR1や抹消血のMDR1、GRなど生体肝移植患者における免疫抑制療法に対する有用なバイオマーカーを発見することができ、当初の目標をおおむね達成することができた。

Research Products

• [Journal Article] Effect of intestinal CYP3A5 on postoperative tacrolimus trough levels in living-donor liver transplant recipients (2006)
  • Author(s): Uesugi M
  • Journal Title: Pharmacogenet Genomics 16・2 Pages: 119-127
• [Journal Article] Intestinal MDR1/ABCB1 level at surgery as a risk factor of acute cellular rejection in living-donor liver transplant patients. (2006)
  • Author(s): Masuda S
  • Journal Title: Clin Pharmacol Ther 79・1 Pages: 90-102
• [Journal Article] Cyclosporine exposure and calcineurin phosphatase activity in living-donor liver transplant patients : twice daily versus once daily dosing (2006)
  • Author(s): Fukudo M
  • Journal Title: Liver Transpl 12・2 Pages: 292-300
• [Journal Article] Pharmacodynamic analysis of tacrolimus and cyclosporine in living-donor liver transplant patients (2006)
  • Author(s): Fukudo M
  • Journal Title: Clin Pharmacol Ther 78・2 Pages: 168-181
• [Journal Article] Initial dosage adjustment for oral administration of tacrolimus using the intestinal MDR1 level in living-donor liver transplant recipients. (2005)
  • Author(s): Masuda S
  • Journal Title: Transpl Proc 37・4 Pages: 1728-1729
• [Journal Article] Transient up-regulation of P-glycoprotein reduces tacrolimus absorption after ischemia-reperfusion injury in rat ileum (2005)
  • Author(s): Omae T
  • Journal Title: Biochem Pharmacol 69・4 Pages: 560-567
• [Journal Article] 移植肝の遺伝子情報とタクロリムス体内動態の個体間変動 (2005)
  • Author(s): 増田智先
  • Journal Title: 臨床薬理の進歩 26(印刷中)
• [Journal Article] Increased protein level of PEPT1 intestinal H^+/peptide cotransporter up regulates absorption of glycylsarcosine and ceftibuten in 5/6 nephrectomized (2005)
  • Author(s): Shimizu, Y
  • Journal Title: Am J Physiol Gastrointestinal Liver Physiol (印刷中)
• [Journal Article] Transient up-regulation of P-glycoprotein reduces tacrolimus absorption after ischemia-reperfusion injury in rat ileum. (2005)
  • Author(s): Omae, T
  • Journal Title: Biochem Pharmacol 69・4 Pages: 560-567
• [Journal Article] Distinct inhibitory effects of tacrolimus and cyclosporin A on calcineurin phosphatase activity. (2005)
  • Author(s): Fukudo, M
  • Journal Title: J Pharmacol Exp Ther 312・2 Pages: 816-825
• [Journal Article] カルシニューリン阻害薬の処方 (2004)
  • Author(s): 増田智先
  • Journal Title: 治療学 38・10 Pages: 1166-1167
• [Journal Article] Decreased Expression of Glucose and Peptide Transporters in Rat Remnant Kidney (2004)
  • Author(s): Nakamura, N
  • Journal Title: Drug Metab Pharmacokin 19・1 Pages: 41-47
• [Journal Article] Expression levels of renal organic anion transporters (OATs) and their correlation with anionic drug excretion in patients with renal disease. (2004)
  • Author(s): Sakurai, Y
  • Journal Title: Pharm Res 21・1 Pages: 61-67
• [Journal Article] CYP3A5^*1-carrying graft liver reduces the concentration/oral dose ratio of tacrolimus in recipients of living-donor liver transplantation. (2004)
  • Author(s): Goto, M
  • Journal Title: Pharmacogenetics 14・7 Pages: 471-478
• [Journal Article] Gene expression variance based on random sequencing in rat remnant kidney. (2004)
  • Author(s): Horiba, N
  • Journal Title: Kidney Int 66・1 Pages: 29-45
• [Journal Article] Common single nucleotide polymorphisms of MDRl gene have no influence on its mRNA expression level of normal kidney cortex and renal cell carcinoma in Japanese nephrectomized patients. (2004)
  • Author(s): Uwai, Y
  • Journal Title: J Hum Genet 49・1 Pages: 40-45
• [Journal Article] Isolation and characterization of a digoxin transporter and its rat homologue expressed in the kidney. (2004)
  • Author(s): Mikkaichi, T
  • Journal Title: Proc Natl Acad Sci USA 101・10 Pages: 3569-3574
• [Journal Article] Tacrolimus therapy according to mucosal MDRl levels in recipients of small bowel transplantation. (2004)
  • Author(s): Masuda, S
  • Journal Title: Clin Pharmacol Ther 75・4 Pages: 352-361
• [Publications] Masuda S: "Tacrolimus therapy according to mucosal MDR1 levels in recipients of small bowel transplantation"Clin Pharmacol Ther. (in press).
• [Publications] Horiba N: "Gene expression variance based on random sequencing in rat remnant kidney"Kidney Int. (in press).
• [Publications] Sakurai Y: "Expression levels of renal organic anion transporters (OATs) and their correlation with anionic drug excretion in patients with renal disease"Pharm Res. 21. 61-67 (2004)
• [Publications] Uwai Y: "Common single nucleotide polymorphisms of MDR1 gene have no influence on its mRNA expression level of normal kidney cortex and renal cell carcinoma in Japanese nephrectomized patients."J Hum Genet. 49. 40-45 (2004)
• [Publications] Nakamura N: "Decreased Expression of Glucose and Peptide Transporters in Rat Remnant Kidney"Drug Metab Pharmacokin. 19. 41-47 (2004)
• [Publications] Horiba N: "Cloning and characterization of a novel Na^+-dependent glucose transporter NaGLT1 in rat kidney"J Biol Chem. 278. 14669-14676 (2003)
• [Publications] Masuda S: "Enhanced expression of enterocyte P-glycoprotein depresses cyclosporine bioavailability in a recipient of living-donor liver transplantation"Liver Transpl. 9. 1108-1113 (2003)
• [Publications] Goto M: "Decreased expression of P-glycoprotein during differentiation in the human intestinal cell line Caco-2"Biochem Pharmacol. 66. 163-170 (2003)
• [Publications] Horiba N: "Na^+-dependent fructose transport via rNaGLT1 in rat kidney"FEBS Lett. 546. 276-280 (2003)
• [Publications] 増田智先: "臓器移植患者における個腹化免疫抑制療法"臨床薬理. 34. 279-282 (2003)
• [Publications] Masuda S: "Functional characteristics and pharmacokinetic significance of kidney-specific organic anion transporters, OAT-K1 and OAT-K2, in the urinary excretion of anionic drugs"Drug Metab Pharmacokin. 18. 91-103 (2003)
• [Publications] 増田智先: "抗真菌薬とCYP・トランスポーター(特集:チトクロムP450・トランスポーターと臨床上重要な相互作用)"薬局. 54. 2801-2807 (2003)