Naotsugu Ichimaru

Changes in lipid metabolism and effect of simvastatin in renal transplant recipients induced by cyclosporine or tacrolimus

Hyperlipidemia is frequently developed following renal transplantation and results in worsening of the patients prognosis. In study 1, the effects of immunosuppressants, cyclosporine (CsA) and tacrolimus on serum lipids were compared in-patients undergoing renal transplantation. The study included 32 cases of renal transplantation recipients who randomized to the CsA treatment group (15 patients) and the tacrolimus group (17 patients). Before and 1 month after the transplantation, we assessed the serum lipid levels, apolipoprotein levels, the concentrations of cholesterol in the respective lipoprotein fractions and the enzyme activities related to lipid-metabolism. The serum lipid levels in both groups were significantly increased at 1 month after renal transplantation. In the CsA group, there were significant increases in cholesterol contents in very-low-density lipoprotein (VLDL), LDL2 and HDL2 fractions, whereas, in the tacrolimus group, cholesterol content was increased in VLDL and HDL2 fractions. In study 2, 1 month after renal transplantation, 19 patients with hypercholesterolemia (total cholesterol (TC) >200 mg/dl) and hypertriglyceridemia (triglyceride (TG) >150 mg/dl) were treated with simvastatin 5-10 mg/day for 6 months. Simvastatin treatment significantly decreased serum TC (240+/-29-200+/-22 mg/dl, P<0.001), low-density lipoprotein cholesterol (LDL-C; 114+/-20-99+/-17 mg/dl, P<0.05) and TG levels (217+/-103-130+/-38 mg/dl, P<0.01). In addition, there were significant decreases in very-low-density lipoprotein cholesterol (VLDL-C; 53+/-20-34+/-15 mg/dl, P<0.001). The Cmax and AUC of simvastatin were increased about eight-fold, when simvastatin was given in combination with CsA. In contrast, no significant changes in simvastatin levels were observed when combination with tacrolimus. Although simvastatin levels were increased with CsA, there were no abnormal changes in renal and liver functions, creatinine phosphokinase (CPK) levels or in incidence of adverse effects.

Early induction of apoptosis in androgen‐independent prostate cancer cell line by FTY720 requires caspase‐3 activation

We previously reported that FTY720, a metabolite from Isaria sinclairii, induced some cancer cells to undergo apoptosis, and that FTY720‐induced apoptosis was not related to Fas‐antigens. In this study we investigated whether FTY720 was able to induce apoptosis in an androgen‐independent prostate cancer cell line, DU145, which is not only resistant to androgen‐withdrawal‐induced apoptosis but also Fas‐ and TNF‐α‐mediated apoptosis.

Erythropoietin protects the kidneys against ischemia reperfusion injury by activating hypoxia inducible factor-1alpha.

Background. Ischemia/reperfusion (I/R) injury is closely associated with tissue damage in various organs, as well as in kidney transplants. Erythropoietin (EPO) has been shown to have a cytoprotective effect against hypoxia. We examined the effect of EPO against renal I/R injury and the underlying mechanism. Methods. Human umbilical vein endothelial cells and human renal proximal tubular epithelial cells were cultured under hypoxic conditions with various EPO concentrations at 37°C and examined the mechanism of cell proliferation by EPO. Moreover, to demonstrate the renoprotective effect in vivo, we treated Sprague-Dawley rats with 100 IU/kg EPO every 2 days for 2 weeks (a total of 6 doses). One day after the last injection, the operations to produce renal I/R injury (bilateral renal occlusion for 60 min) were done, and rats were killed at the end of the reperfusion period (24 hr and 72 hr after reperfusion began). Results. First, we demonstrated in vitro that EPO increased hypoxia inducible factor-1α (HIF-1α) expression and stimulated proliferation of both cells under hypoxic conditions. Next, we demonstrated in vivo that EPO treatment increased the number of HIF-1α-positive cells, and markedly induced the expression of vascular endothelial growth factor messenger RNA. Using pimonidazole, a molecular probe that detects hypoxia, we found that EPO markedly attenuated tubular hypoxia, and reduced the number of terminal transferase dUTP nick end labeling–positive apoptotic cells and α-smooth muscle actin–positive interstitial cells. Conclusions. We suggested a novel HIF-1α induction pathway by EPO under hypoxic conditions. Thus, EPO may protect the kidneys against ischemia reperfusion injury by activating HIF-1α.

Japan's experience with living-donor kidney transplantation across ABO barriers

Given the severe shortage of deceased-donor organs in Japan, the use of living-donor kidney transplantation (LKT) strategies, such as ABO-incompatible living-donor kidney transplantation, has expanded rapidly. ABO-incompatible LKT was initially performed following splenectomy and antibody removal; however, immunosuppressive protocols for ABO-incompatible LKT have changed markedly over recent years in Japan. Mycophenolate mofetil, calcineurin inhibitors and corticosteroids are now used to achieve desensitization before transplantation, and thereby suppress acute antibody-mediated rejection. In addition, many institutions now use anti-CD20 antibody (rituximab) instead of splenectomy, which seems to have markedly reduced the incidence of acute antibody-mediated rejection. ABO-incompatible LKT recipients in Japan typically undergo 2–4 sessions of plasma exchange or double-filtration plasmapheresis before transplantation to remove anti-ABO antibodies. In contrast to many Western countries, antibody removal is not routinely performed after kidney transplantation in Japan. Among 1,012 ABO-incompatible LKTs carried out at 92 Japanese institutions during the period 1989–2006, 1-year, 3-year, 5-year and 10-year patient survival rates were 95%, 93%, 91% and 87%, respectively, and the corresponding graft survival rates were 90%, 86%, 80% and 63%, respectively. These data indicate that the outcomes of ABO-incompatible LKT are comparable to those of ABO-compatible LKT. This Review summarizes Japans experience with ABO-incompatible LKT.

Superagonist CD28 antibody preferentially expanded Foxp3-expressing nTreg cells and prevented graft-versus-host diseases.

Regulatory lymphocytes play a pivotal role in preventing organ-specific autoimmune disease and in induction and maintenance of tolerance in various experimental transplantation models. The enhancement of the number and activity of peripheral CD4+CD25+ Treg cells is an obvious goal for the treatment of autoimmunity and for the suppression of alloreactions. The present study demonstrates that naturally occurring CD4+CD25+ Treg (nTreg) cells preferentially proliferate to a fourfold increase within 3 days in response to the administration of a single superagonistic CD28-specific monoclonal antibody (supCD28 mAb). The appearance of increased Foxp3 molecules was accompanied with polarization toward a Th2 cytokine profile with decreased production of IFN-γ and increased production of IL-4 and IL-10 in the expanded Treg subset. Adoptive transfer of supCD28 mAb-expanded cells in a graft-versus-host disease (GvHD) model induced a potent inhibition of lethality. These results suggest that this therapeutic effect is mediated by the in vivo expansion of nTreg cells. Taken together, these data demonstrate that supCD28-mAb may target nTreg cells in vivo and maintain and enhance their potent regulatory functions for the treatment GvHD.

Treatment Adherence in Renal Transplant Recipients: A Questionnaire Survey on Immunosuppressants

INTRODUCTION To achieve a high graft survival rate, patient adherence to immunosuppressive therapy is critical. It is extremely difficult to establish the actual adherence status of transplant recipients; only a few surveys on the issue have been performed in Japan. METHODS We conducted a questionnaire survey mainly on treatment adherence to calcineurin inhibitors among renal transplant recipients. RESULTS The survey demonstrated some degree of nonadherence in a relatively high percentage of the patients. The adherence rate was significantly lower for the evening than the morning dose (McNemar test, P < .001). It significantly decreased with time following transplantation for both the morning and the evening doses (logistic regression analysis, P = .025 and <.001, respectively). CONCLUSIONS Immunosuppressive treatment places a substantial burden on patients, some of whom cannot continue regular treatment at specified time points due to daily life restrictions after they have returned to work.

Carbamylated Erythropoietin Improves Angiogenesis and Protects the Kidneys from Ischemia-Reperfusion Injury:

Several studies have shown that erythropoietin (EPO) can protect the kidneys from ischemia-reperfusion injury and can raise the hemoglobin (Hb) concentration. Recently, the EPO molecule modified by carbamylation (CEPO) has been identified and was demonstrated to be able to protect several organs without increasing the Hb concentration. We hypothesized that treatment with CEPO would protect the kidneys, partly due to the increased peritubular capillaries. The therapeutic effect of CEPO was evaluated using an endothelial tube formation assay in vitro, and a rat ischemia-reperfusion injury model in vivo. EPO treatment showed the tendency of increased tube formation, while CEPO treatment induced more capillary-like formation than EPO. Ischemia-reperfusion-induced kidneys exhibited characteristic nuclei of apoptosis in tubular epithelial cells with decreased peritubular capillaries, while EPO treatment inhibited tubular apoptosis with preserved endothelial cells. Moreover, CEPO-treated kidneys showed minimal tubular apoptosis with increased peritubular capillary endothelial cells. In conclusion, we identified a new therapeutic approach using CEPO to protect kidneys from ischemia-reperfusion injury by promoting angiogenesis.

Risk factors for malignancy in Japanese renal transplant recipients

Among recipients of renal transplants, the incidences of renal cancer and gastrointestinal cancer are higher and that of skin cancer is much lower in Japan than in Europe and North America.

Superagonistic CD28 Antibody Induces Donor-Specific Tolerance in Rat Renal Allografts

The ultimate goal of organ transplantation is to establish graft tolerance where CD4+CD25+FOXP3+ regulatory T (Treg) cells play an important role. We examined whether a superagonistic monoclonal antibody specific for CD28 (CD28 SA), which expands Treg cells in vivo, would prevent acute rejection and induce tolerance using our established rat acute renal allograft model (Wistar to Lewis). In the untreated or mouse IgG‐treated recipients, graft function significantly deteriorated with marked destruction of renal tissue, and all rats died by 13 days with severe azotemia. In contrast, 90% of recipients treated with CD28 SA survived over 100 days, and 70% survived with well‐preserved graft function until graft recovery at 180 days. Analysis by flow cytometry and immunohistochemistry demonstrated that CD28 SA induced marked infiltration of FOXP3+ Treg cells into the allografts. Furthermore, these long‐surviving recipients showed donor‐specific tolerance, accepting secondary (donor‐matched) Wistar cardiac allografts, but acutely rejecting third‐party BN allografts. We further demonstrated that adoptive transfer of CD4+CD25+ Treg cells, purified from CD28 SA‐treated Lewis rats, significantly prolonged allograft survival and succeeded in inducing donor‐specific tolerance. In conclusion, CD28 SA treatment successfully induces donor‐specific tolerance with the involvement of Treg cells, and thus the therapeutic value of this approach warrants further investigation and preclinical studies.

A novel immunosuppressive drug, FTY720, prevents the cancer progression induced by cyclosporine

Cyclosporine A (CsA), the most frequently used immunosuppressive drug, has been reported to induce cancer by a cell-autonomous mechanism. Herein, we report that FTY720, a novel immunosuppressant, prevents CsA-induced alterations in both morphology and cell motility at a low concentration (0.1 microM) and induces the CsA-treated cancer cells to undergo apoptosis at a higher concentration (more than 5 microM). The inhibitory activity of FTY720 is unrelated to the decrease of TGF-beta. We believe that a combination treatment with FTY720 and CsA not only results in a synergistic effect on allografts, but also, reduces the incidence of cancer in transplant patients.