An immunosuppressive regimen using FTY720 combined with cyclosporin in canine kidney transplantation

FTY720 induces apoptosis, specifically in lymphocytes, and prolongs allograft survival in rats and dogs. The purpose of this study was to define an effective range of FTY720 doses that could be combined with a suboptimal dose (10 mg/kg) of cyclosporin for canine kidney allograft recipients. The combination significantly prolonged allograft survival in all groups receiving FTY720 at a dose of 0.1, 0.3, 1.0, or 3.0 mg/kg. None of the recipients died due to notable side effects of the drug. In peripheral blood, the number of lymphocytes was extremely low, whereas the percentage of granulocytes increased during FTY720 administration. No significant difference in cyclosporin trough levels was observed between the cyclosporin-alone group and the combination groups. We conclude from the present study that FTY720 has a potent effect at an extremely low dose and a wide therapeutic window when combined with cyclosporin in canine kidney transplants. Received: 16 May 1997 Received after revision: 6 October 1997 Accepted: 19 November 1997     

Effect of peritransplant FTY720 alone or in combination with post-transplant tacrolimus in a rat model of cardiac allotransplantation

FTY720 is a recently discovered compound that is derived from the fungus Isaria sinclairii. Using a DA donor-to-LEW recipient rat combination, we assessed the efficacy of peritransplant FTY720 alone or in combination with post-transplant tacrolimus on the survival of cardiac allografts. Peritransplant FTY720 given orally at a dose of 5 mg/kg on days –1 and 0 prolonged graft survival from 5 to 13 days (P < 0.05). Combining peritransplant FTY720 with post-transplant tacrolimus resulted in a further prolongation of allograft survival. The lymphocyte count in transplanted rats decreased within 24 h to 46.6 %. Analysis of lymphocyte subsets by FACS revealed that FTY720 affected the total population of CD3-bearing T cells while the ratio of CD4 to CD8 cells remained unchanged. Kidney and liver biochemistry remained elevated for 2 weeks. In conclusion, FTY720 is a powerful immunosuppressive agent when used as induction therapy and may have an additive effect – perhaps a synergistic one – with post-transplant tacrolimus. Received: 27 October 1997 Received after revision: 23 March 1998 Accepted: 15 April 1998     

Effect of FTY720 and Ex Vivo Graft Irradiation in Rat Small Bowel Transplantation: Expression of Mucosal Addressin Cell Adhesion Molecule-1

Purpose We performed a semiquantitative analysis of the expression of Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and gut-associated tissues (GALT) during small bowel graft rejection in the rat to confirm the effect of FTY720 and ex vivo graft irradiation. Methods Small bowel transplantations (SBT) were performed from BN rats to LEW rats. Four groups of SBT animals were studied on days 3, 5, and 7 after operations (untreated, FTY720, ex vivo graft irradiation, FTY720+ex vivo graft irradiation). Indirect immunoperoxidase staining was performed against CD4 and MAdCAM-1. The number of CD4-positive cells in the allografts was also analyzed by flow cytometry. Results The graft survival was prolonged only in the FTY720-treated groups. The SBT allografts treated by FTY720 demonstrated less infiltration, but the ex vivo graft irradiation group did not show any effect on its expression. In the FTY720-treated groups, MAdCAM-1 expression on high endothelial venules (HEVs) in Peyer's patches (PPs) was upregulated and its expression on endothelial cells of vessels in the lamina propria was downregulated in comparison with the allograft group without FTY720. Conclusions It is important to prevent the infiltration of CD4-positive cells, the downregulation of MAdCAM-1 expression on HEVs in PPs and the upregulation of MAdCAM-1 expression on endothelial cells of vessels in the lamina propria for the prolongation of graft survival.     

FTY720诱导大鼠心脏移植物长期存活

目的 观察FTY720对大鼠同种异体心脏移植物存活时间的影响。方法 进行SD Wistar大鼠的腹部异位心脏移植，将受者随机分为对照组、甲泼尼龙(MP)组、环孢素A((SsA)组、FTY720组、FTY720与CsA二药联用组和FTY720、CsA及MP三药联用组，各组按分组要求分别于术前3d至术后14d通过灌胃给予FTY720和CsA，术前1d至术后2d腹腔注射给予MP，观察各组动物术后外周血淋巴细胞数量变化和移植物存活时间。结果 FTY720组、二药联用组和三药联用组的大鼠外周血淋巴细胞在给药后3h开始明显下降，停药后开始回升，至停药14d后恢复正常；移植心脏的存活时间，对照组平均为7．8d，CsA组为16．0d，MP组为27．6d，三药联用组为16．8d，而FTY720组和二药联用组分别超过了150d和124d。结论 FTY720可诱导同种异体大鼠心脏移植物长期存活。     

FTY720介导淋巴细胞凋亡抑制小肠移植的移植物抗宿主免疫反应

目的 探讨免疫调节药物FTY720对小肠移植后急性移植物抗宿主病（GVHD）的治疗效果及其作用机制.方法 应用Wistar-Furth（WF）大鼠作为供体,WF和ACI大鼠的子代（F1）作为受体,同种异基因异位全小肠移植的技术方法建立GVHD的动物模型.移植受体分为实验组和对照组,每组6只.实验组从移植手术当日开始予以FTY720治疗,持续14 d;对照组在相同的时间段口服蒸馏水.术后第15天,提取受体靶器官肝脏、小肠及移植物小肠的淋巴细胞,应用免疫组织化学（免疫组化）TUNEL法和流式细胞仪检测两组淋巴细胞凋亡的变化.结果 对照组大鼠术后均死亡于GVHD,平均生存时间（16.0±1.7）d,实验组大鼠均长期成活超过100 d,两组差异具有统计学意义（P＜0.01）.免疫组化TUNEL法检测结果显示,实验组肝脏和移植物小肠黏膜的淋巴细胞凋亡比率均明显高于对照组,差异具有统计学意义（P＜0.05）.流式细胞技术分析结果显示,实验组大鼠移植物小肠黏膜内凋亡的淋巴细胞百分比为19.4%,明显高于对照组的11.8%（P＜0.05）;而肝脏凋亡的淋巴细胞百分比两组差异无统计学意义（P＞0.05）.结论 FTY720可能通过诱导淋巴细胞的凋亡,减少和抑制GVHD对靶器官的损害,改善移植大鼠的预后.     

FTY720预防大鼠肾脏缺血再灌注损伤的实验研究

目的:研究新型免疫抑制剂FTY720对大鼠肾脏缺血再灌注损伤(IRI)的预防作用.方法:制备大鼠肾脏IRI模型,从下腔静脉注入不同剂量的FTY720,观察术后第1、2、3、5、7 d血清肌酐值(Scr)和术后第2、7 d外周血淋巴细胞数(PLC)的变化,并在术后第2 d取肾脏作组织学检查观察急性肾小管坏死的情况.结果:FTY720处理组动物术后Scr水平显著低于对照组并呈剂量依赖性;FTY720处理组术后第2 d的PLC显著低于对照组;组织学检查显示FTY720处理组肾脏的缺血性损伤轻于对照组.结论:FTY720可以减少PLC,对大鼠肾脏IRI有预防作用.     

A new immunosuppressant, FTY720, in canine kidney transplantation: effect of single-drug, induction and combination treatments

Three different types of treatment were conducted to clarify the properties of a novel immunomodulator, FTY720, in canine kidney allograft models. Survival, biochemical and hematological tests, pharmacokinetics, and histopathology of grafts and extra-renal organs were analyzed. Accompanying a remarkable reduction in circulating lymphocytes, single-drug treatment of FTY720, ranging from 0.05 to 10 mg/kg, exhibited significant prolongation of graft survival without a dose-dependent effect. Short-course induction with FTY720 at 5 mg/kg per day exhibited similar anti-rejection effects as did single-drug treatment but no advantage in rescuing ongoing rejection. In combination with cyclosporine (CsA; 5 mg/kg) or tacrolimus (FK; 0.5 mg/kg), FTY720 had an additive effect. Trough blood concentrations of FTY720 were linearly correlated with dose. No animal showed critical adverse effects at any point. FTY720 holds promise as a candidate in a new category of drugs that can be combined with conventional agents for induction and maintenance immunosuppression in clinical organ transplantation.     

FTY720,40-氧-(2-羟乙基)-雷帕霉素和环孢素A延长小鼠心脏移植物存活时间的对比研究

目的 FTY720和40-氧-(2-羟乙基)-雷帕霉素(RAD)是两种新型免疫抑制剂。为评估这两种药物的效果,我们以小鼠心脏移植为模型,对比观察了这两种药物和环孢素A(CsA)对移植物存活时间的影响。方法 供体为BALB/C小鼠,受体为C57BL/6小鼠,受鼠随机分为4组,每组6只:A组空白对照;B组每日管饲CsA 10 mg/kg体重;C组每日管饲RAD 3 mg/kg体重;D组每日管饲FTY 3 mg/kg体重。各服药组均由移植当日开始喂药,至移植心停跳或术后14 d停药。结果 各组的存活天数分别为:A组6、7、8、8、9、9;B组9、9、10、11、12;C组10、12、13、13、14;D组10、12、16、16、17、18。B、C组各有1例带心死亡。所有移植心都出现程度不同的急性排斥反应征象。结论 单独使用RAD或FTY可显著延长小鼠心脏移植物的存活时间。在各所选剂量上,CsA和RAD差异无显著性(P>0.05),FTY的效果明显优于CsA和RAD。FTY和RAD是较有前途的新型免疫抑制剂。     

Effect of FTY720 on immunoregulation in concordant xenotransplantation

Abstract The present study was designed to analyze the immunosuppressive activity of FTY720 in concordant xenotransplantation. When T and B lymphocytes of human peripheral blood were incubated with FTY720, the number of viable cells decreased in a dose-dependent manner at doses higher than 4×10^-5 M. DNA fragmentation was observed at doses higher than 4×10 ^-5 M in B cell-rich fractions. These data demonstrate that FTY720 is cytotoxic to B lymphocytes as well as T lymphocytes and apoptosis may play an important role in this cytotoxicity. Golden Syrian hamsters were the donors and Lewis rats the recipients of skin grafts. The recipients were divided into the following four groups; (1) untreated recipients, (2) FTY720 (5mg/kg per day) was administered orally for 8 days (days -1–6), (3) FK 506 (1 mg/kg per day) was injected i. m. for 7 days (days 0–6), and (4) FK506 (1 mg/kg per day) was injected i.m. for 7 days (days 0–6) and FTY720 (5 mg/kg per day) was administered orally for 8 days (days-1–6). The mean graft survival times in groups 1–4 were.7 ± 0.52 days ( n = 6), 12.0 ± 0.71 days ( n = 6), 13.2 ± 1.6 days ( n = 6), and 37.7 ± 4.3 days ( n = 6), respectively. There was a significant difference in the mean survival time between groups one and four. Combined therapy with FTY720 and FK506 is a useful tool for immunoregulation in xenotransplantation.     

FTY720 attenuates tubulointerstitial inflammation and fibrosis in subtotally nephrectomized rats

Abstract

Tubulointerstitial fibrosis is a common pathway that leads to kidney failure, and persistent tubulointerstitial inflammation is a key event in the development of tubulointerstitial fibrosis. The new immunosuppressive drug FTY720 modifies lymphocyte migration into injured tissues by sequestering lymphocytes within secondary lymphoid organs. However, its therapeutic effect on tubulointerstitial inflammation and fibrosis had not been well understood. This study was designed to explore the effect of FTY720 on tubulointerstitial inflammation and fibrosis in subtotally nephrectomized (SNX) rats. In total, 24 male Sprague–Dawley rats were used. Seven days after 5/6 nephrectomy, rats were randomized to FTY720 (1?mg/kg/d) and placebo-treated groups. Sham-operated rats served as controls. FTY720 significantly attenuated the rise in proteinuria, serum creatinine, urea nitrogen and N-acetyl-β-D-glucosaminidase activity in SNX rats, and reduced the count of peripheral white blood cells and lymphocytes in SNX rats. Morphological analysis revealed that there was severe tubulointerstitial inflammation and fibrosis in SNX group and much more tubulointerstitial infiltrating inflammatory cells with high expression of CD3, CD4, CD8, CD20, CD68, CD163 and CCR-7 in SNX group, as compared with the controls, but the lesions were attenuated significantly by treatment with FTY720. Furthermore, the expressions of proinflammatory molecules (IL-6, TNF-α and MCP-1), profibrotic molecule (TGF-β1) and production of extracellular matrix proteins such as fibronectin and types I and III collagens were upregulated in SNX rats. FTY720 administration significantly reduced these abnormalities. In summary, FTY720 exerts therapeutic effects on tubulointerstitial fibrosis in SNX rats by inhibiting the tubulointerstitial inflammatory response.     

FTY720 Prevents Anti-CD4 mAb-Induced Tolerance but Cannot Reverse Established Tolerance in a Rat Kidney Transplantation Model

FTY720 is highly effective in various models of transplantation and autoimmunity. In order to find drugs that act synergistically with a tolerance-inducing nondepleting anti-CD4 mAb we studied this combination in a strong DA to LEW kidney transplantation model. Rats were treated with 0.3 mg/kg of FTY720 for 14 days and anti-CD4 mAb RIB5/2, alone or in combination. After kidney transplantation serum creatinine and blood lymphocyte counts were monitored. Immunohistology, ELISPOT and TaqMan trade mark -PCR analysis of biopsies were performed. Short-term application of RIB5/2 but not FTY720 induced long-term survival of kidney transplants. Moreover, the combination of FTY720 + RIB5/2 prevented tolerance induction. In the combination group serum creatinine levels increased 1 week after cessation of therapy and all rats died from uremia within 72 days. Intragraft immunohistology, ELISPOT and real-time RT-PCR analysis at day 21 demonstrated an enhanced T-cell infiltration and activation but a diminished up-regulation of protective genes in the grafts from recipients receiving the combination therapy. In contrast, delayed application of FTY720 to RIB5/2-treated rats did not interact with RIB5/2-induced tolerance. In summary, FTY720 is powerful in preventing intragraft infiltration by naive T cells but this might also affect the early development of graft-protecting regulatory T cells and tolerance induction.     

Evidence that FTY720 induces rat thymocyte apoptosis

FTY720, a novel immunomodulator with the potential to improve immunosuppressive therapy after organ transplantation, is currently under clinical investigation. FTY720 drastically decreases blood lymphocytes, especially T cells, accelerating lymphocyte homing to secondary lymphoid organs. However, its immunosuppressive effects remain unknown. We investigated these effects in rat thymocytes. Rats were intramuscularly injected with 10mg/kg/day FTY720 or saline for 7days. Thymuses were removed on days 0, 1, 3, 5, 7 and 14 after treatment. Three-color analysis was performed with a flow cytofluorometer. Apoptotic nuclei in the tissue sections were identified by TUNEL. Genomic DNA was then extracted and samples were electrophoresed on 2.0% agarose gel. FTY720 reduced the total number of thymocytes and, with time, significantly reduced the percentage of CD4+8+ TCRalphabeta(negative/low) thymocytes. Light microscopy of thymuses of FTY720-treated rats revealed obvious reductions in the size of the cortical region. TUNEL analysis showed that FTY720 induced thymocyte apoptosis in the cortical region. Furthermore, DNA fragmentation was observed in thymocytes treated with FTY720, indicating thymocyte apoptosis. FTY720 reduced the number of CD4+8+ thymocytes before TCRalphabeta expression resulting in impaired thymocyte differentiation and maturation. This might be an immunosuppressive effect of FTY720.     

The effect of FTY 720 on engraftment in a model of spontaneous allograft acceptance

Further development in organ transplantation requires the utilization of new immunosuppressive drugs that-in addition to being effective against rejection-do not block tolerance. We previously reported that FTY 720, a drug that alters lymphocyte trafficking, has marked anti-rejection properties. We now investigate how FTY 720 influences tolerance in a model of graft acceptance by donor-specific blood transfusion (DSBT). Two different transplant models--heart transplantation (Htx) and intestinal transplantation (Itx)--were studied. We performed orthotopic Itx and heterotopic Htx using fully mismatched inbred male RA (RT1(p)) and PVG (RT1(c)) rats as donors and recipients. Tolerance was induced by DSBT on pre-transplant day -12. To test the effect of FTY 720 on DSBT-induced tolerance, we administered FTY 720 orally prior to DSBT. Itx: control rats succumbed to rejection at 18+/-4 days. DSBT alone prolonged survival to 101.9+/-18 days (P<0.05 vs untreated). Long-term survivors were tolerant (acceptance of secondary donor-specific Htx). Adjunction of FTY 720 prior to DSBT reduced survival to 55.9+/-44.7 days (P<0.05). However, long-term survivors still accepted secondary donor-specific Htx. Htx: control rats survived 9+/-0.6 days. DSBT alone prolonged survival indefinitely (>120 days) and induced tolerance (acceptance of secondary donor-specific Htx). Unlike in Itx, adjunction of FTY 720 prior to DSBT did not reduce Htx survival. Acceptance of secondary donor-specific Htx was not influenced by FTY 720. In Itx, FTY 720 counteracts the beneficial effect of pre-transplant DSBT and triggers acute rejection of primary, but not secondary grafts. In Htx, however, FTY 720 allows full development of tolerance. The mechanisms by which FTY 720 causes rejection in primary intestinal but not in heart grafts need to be elucidated.     

FTY720/Cyclosporine Regimens in De Novo Renal Transplantation: A 1-Year Dose-Finding Study

FTY720 is a novel immunomodulator being investigated for rejection prophylaxis in renal transplantation when combined with full-dose cyclosporine (CsA; FDC). This 1-year phase II study compared FTY720 plus FDC (Neoral) with FTY720 plus reduced-dose CsA (RDC) and mycophenolate mofetil (MMF) plus FDC in de novo renal transplant patients. Patients were randomized 2:2:2:1 to FTY720 5 mg plus RDC (n = 72); FTY720 2.5 mg plus RDC (n = 74); FTY720 2.5 mg plus FDC (n = 76); or MMF plus FDC (n = 39) for 12 months. CsA exposure in the RDC group was reduced on average by 50% as assessed by C(2) monitoring. The primary efficacy endpoint was the composite incidence of biopsy-proven acute rejection (BPAR), graft loss, death or premature study discontinuation. The incidences for this composite endpoint were 24% and 22%, respectively, for FTY720 5 mg plus RDC and FTY720 2.5 mg plus FDC versus 39% for MMF plus FDC. Patients receiving FTY720 2.5 mg plus RDC were discontinued from treatment due to risk of under-immunosuppression. FTY720 2.5 mg plus FDC and FTY720 5 mg plus RDC were safe and effective in de novo renal transplant patients over 12 months.     

转化生长因子-β1转基因联合FTY720对大鼠心脏移植物缺血-再灌注损伤的影响

目的 探讨经冠脉灌注转化生长因子(TGF)-β1基因联合FTY720对移植心脏缺血-再灌注损伤(IRI)的影响及其机制.方法 实验分为空白对照组、空载体组、FTY720组、转基因组和转基因+FTY720组.心脏移植8 h后切取移植心脏,免疫组织化学检测mTGF-β1、ICAM-1、核转录因子(NF)-κB表达;逆转录-聚合酶链反应(RT-PCR)检测mTGF-β1 mRNA转录强度;测定超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、髓过氧化物酶(MPO)活性.结果 mTGF-β1成功转到心肌细胞,转基因组和转基因+FIY720组mTGF-β1的表达强度分别是(1.08±0.24)和(1.16±0.22),明显高于其他3组(P<0.01);而两组ICAM-1的表达积分分别是(2.43±0.46)和(1.90±0.20),NF-κB的表达积分分别是(9.80±1.85)和(10.10±2.27),较其他3组显著下调(P<0.01);FRY720组、转基因组和转基因+FTY720组心肌细胞凋亡指数分别是(9.20±1.12)、(5.90±1.09)和(5.40±0.77),显著减少(P<0.01);FTY720组、转基因组和转基因+FTY720组SOD活性分别是(51.03±5.54)、(55.91±6.66)和(73.42±6.42)U/mg,明显升高(P<0.01),MDA含量(10.90±1.93)、(11.02±2.45)和(9.28±1.64)U/g,明显下降(P<0.01);而MPO活性分别是(4.38±1.43)、(4.63±1.04)和(3.16±0.64)U/g,亦明显下降(P<0.01);转基因和FTY720两因素对减轻心肌细胞凋亡以及对SOD、MDA和MPO的影响存在交互作用(P<0.05).结论 TGF-β1和FTY720均具有减轻移植心脏缺血-再灌注损伤的作用,机制可能与抑制心肌细胞凋亡、下调ICAM-1、NF-κB表达、增高SOD活性等因素有关;两者联合应用在减轻缺血-再灌注损伤方面有协同作用.     

FTY720在鼠类异种胰岛移植排斥反应中的作用

目的 在小鼠异种胰岛细胞移植模型上，研究FTY720在控制异种胰岛移植排斥反应中的作用。方法 使用胰管内胶原酶注射和不连续密度梯度纯化法获取大鼠胰岛，建立小鼠肾被膜下移植模型。受体小鼠随机分为3组：对照组，末使用任何免疫抑制药物；实验1组，自移植当日起每日单独喂服FTY720(1.0mg／kg)；实验2组，亦于移植当日起每日联合喂服FTY720(1.0mg／kg)和环孢霉素A(CsA，15mg／kg)，均连续喂饲14d。分别于术后第3，5，7，14天切取移植物，观察并分析排斥反应。结果 对照组和实验1组，植入。肾被膜下的胰岛组织多在1周内完全被排斥，术后第7天胰岛轮廓消失，仅见大量淋巴细胞浸润。实验2组于移植后第7天及第14天肾被膜下仍可见大量完整的胰岛细胞，几乎未见或偶尔可见淋巴细咆浸润。结论 FTY720单独作为免疫抑制剂并不能抑制鼠类异种胰岛移植的排斥反应；联合应用FTY720及CsA则可有效地抑制鼠类异种胰岛移植排斥反应的发生。     

Sphingosine 1-phosphate receptor modulators: a new class of immunosuppressants

In this review, we summarize how FTY720 came from the lab bench to the bedside by examining its structural similarities to natural occurring sphingosine analogues, the mechanism of action, and clinical applicability to not only transplantation but also autoimmune, oncological, and neurobiological fields. FTY720, a sphingosine 1-phosphate (S1P) analogue, promotes the survival of human and animal allografts by sequestering T lymphocytes within peripheral lymphoid tissue. The mechanism of sequestration is three-fold: (1) T lymphocytes are driven into peripheral lymph nodes in a chemokine dependent manner by FTY720; (2) FTY720 downregulates sphingosine 1-phosphate receptors (S1PRs) on the T lymphocyte surface, rendering it unable to migrate along a S1P gradient; and (3) FTY720 closes stromal gates on the abluminal side of the lymphatic endothelium. Future areas of investigation include developing S1P analogues that have specific agonist binding to S1PRs avoiding side effects seen in non-specific binding.     

腺病毒介导TGF-β 1转基因联合FTY720对大鼠同种异体肺移植缺血-再灌注损伤的保护作用

目的观察腺病毒介导TGF-β₁转基因联合FTY720对大鼠同种异体肺移植缺血-再灌注损伤(IRI)的影响。 方法采用改良的三袖套法吻合技术建立大鼠左肺原位移植模型。以SD大鼠为供受体,随机分为假手术对照组、空白对照组、空载体对照组、TGF-β₁组、FTY720组和TGF-β₁＋FTY720组,每组6只。移植肺再灌注后4 h,检测各项生理指标。 结果腺病毒介导TGF-β₁转基因组荧光现象显著,并确定1×10¹⁰ PFU TGF-β₁基因腺病毒载体为较优转染浓度。肺移植再灌注后4 h,与假手术对照组比较,空白对照组和空载体对照组出现典型的移植肺IRI症状,肺动脉血氧分压(PaO₂)明显降低,二氧化碳分压(PaCO₂)和湿/干重(W/D)比值明显升高,超氧化物歧化酶(SOD)活性明显降低,丙二醛(MDA)含量、髓过氧化物酶(MPO)活性和肿瘤坏死因子-α(TNF-α)含量明显升高。与空白对照组和空载体对照组比较,TGF-β₁组、FTY720组和TGF-β₁＋FTY720组移植肺组织水肿和间质炎症等病理组织学现象明显减轻,PaO₂明显上升,PaCO₂和W/D比值明显下降,SOD活性明显增加,MDA含量、MPO活性和TNF-α含量明显降低。其中,联合处理组病理症状表现出更为明显的减轻趋势。 结论腺病毒介导TGF-β₁转基因联合FTY720能有效减轻大鼠同种异体肺移植IRI。     

The impact of FTY720 (fingolimod) on vasodilatory function and arterial elasticity in renal transplant patients.

BACKGROUND: FTY720 has recently demonstrated a similar efficacy in prevention of acute graft rejection compared with mycophenolate mofetil (MMF) in a large phase III trial of de novo renal transplant recipients. Creatinine clearance, however, was significantly lower in FTY720-treated patients. In the present study, we examined the impact of FTY720 on vascular function in a subgroup of patients of this trial. METHODS: Eighteen patients (12 FTY720, 6 MMF) agreed to be enrolled for an analysis of vascular function. Vascular measurements were performed 1.5 years post-transplant and were repeated 3 months after conversion of the patients from FTY720 to MMF. Arterial stiffness was assessed as augmentation index (AI(75)); endothelium-dependent and -independent vasodilation were measured sonographically as flow-mediated dilation (FMD) and as vasodilation after application of glyceroltrinitrate (GTN). RESULTS: Conversion from 2.5 mg FTY720 to MMF led to a significant improvement of FMD (5.40 +/- 1.84 vs 7.77 +/- 3.36%, P 0.02). AI(75) and GTN tended to be higher after conversion without reaching significance (83 +/- 20.43 vs 78.69 +/- 15.39%, P 0.06; 13.76 +/- 4.52 vs 17.39 +/- 3.76%, P 0.07). In the MMF group, AI(75), FMD and GTN did not significantly change during the observation period. CONCLUSION: The present study constitutes the first analysis of the impact of FTY720 on vascular function in humans and reveals an improvement of arterial vasodilatory function after discontinuation of FTY720 in de novo renal transplant recipients on cyclosporine.     

The Effect of a Novel Immunosuppressant, FTY720, in Mice Without Secondary Lymphoid Organs

Purpose FTY720 is a novel immunosuppressive agent that is thought to reduce the number of peripheral blood lymphocytes (PBL) by directing them toward secondary lymphoid organs such as the lymph nodes and Peyer’s patches. We studied the effects of FTY720 on aly/aly mice that do not have either lymph nodes or Peyer’s patches, as well as on splenectomized aly/aly mice.Methods FTY720 was orally administered by gavage (1 mg/kg) to aly/aly mice as well as to aly/+ mice with and without a splenectomy on 14 consecutive days. The number of lymphocytes was then counted using True Cell beads and flow cytometry. The number of B220-, CD3-, and CD4-positive cells was also determined. In addition, skin grafts from C3H donor mice were performed on these mice.Results FTY720 was effective in significantly reducing the total lymphocyte count as well as the B220-, CD3-, and CD4-positive subtypes in the peripheral blood of aly/+ mice as well as in aly/aly mice with and without a splenectomy. While we did observe allograft skin graft rejection in both the aly/+ mice as well as the aly/aly mice recipients and splenectomized aly/aly mice, the graft survival was prolonged in all groups. The skin allografts treated by FTY720 thus demonstrated fewer lymphocytic cells and less infiltration of CD4-positive cells.Conclusions The administration of FTY720 to mice without lymph nodes, Peyer’s patches, or spleens still results in peripheral lymphopenia. In all groups, FTY720 was found to prevent the infiltration of CD4-positive cells in skin allografts while also prolonging skin allograft survival. The fate of these lymphocytes, however, is unclear.