Nobuyuki Kuwabara

Activation of transcription factors AP-1 and NF-κB in chronic cyclosporine a nephrotoxicity: Role in beneficial effects of magnesium supplementation

Background. It has been shown that the transcription factors activator protein (AP)-1 and nuclear factor (NF)-&kgr;B play a pivotal role in various renal diseases. We aimed to study their activations in chronic cyclosporine A (CsA) nephrotoxicity and evaluate the effect of magnesium (Mg) supplementation and blockade of the renin-angiotensin system (RAS), which are known to ameliorate CsA nephrotoxicity, on these transcription factors. Methods. CsA (15 mg/kg/day) was administered subcutaneously daily to rats maintained on a low-sodium diet for 7, 14, and 28 days. DNA-binding activities of AP-1 and NF-&kgr;B in renal cortex were determined by electrophoretic mobility shift assay. Results. DNA-binding activity of AP-1 and NF-&kgr;B started to increase at day 14 and further elevated at day 28 by CsA treatment. These activations were markedly attenuated when rats were maintained on a high-Mg diet. In contrast, angiotensin-converting enzyme inhibitor (ACEI) had no effect on CsA-induced AP-1 activation. CsA-induced activation of NF-&kgr;B was suppressed by ACEI at day 14, whereas such effect could not be observed at day 28. Conclusions. Renal cortical AP-1 and NF-&kgr;B DNA binding were activated in chronic CsA nephrotoxicity. These activations were induced largely by means of RAS-independent mechanisms. It is suggested that prevention of CsA-induced DNA-binding activation of these transcription factors is at least in part responsible for the beneficial effects of Mg supplementation on CsA nephrotoxicity.

Desensitization Protocol in Highly HLA-Sensitized and ABO-Incompatible High Titer Kidney Transplantation

BACKGROUND A positive crossmatch indicates the presence of donor-specific alloantibodies and is associated with a graft loss rate of >80%; anti-ABO blood group antibodies develop in response to exposure to foreign blood groups, resulting in immediate graft loss. However, a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation has not yet been established. METHODS We treated 6 patients with high (≥1:512) anti-A/B antibody titers and 2 highly HLA-sensitized patients. Our immunosuppression protocol was initiated 1 month before surgery and included mycophenolate mofetil (1 g/d) and/or low-dose steroid (methylprednisolone 8 mg/d). Two doses of the anti-CD20 antibody rituximab (150 mg/m(2)) were administered 2 weeks before and on the day of transplantation. We performed antibody removal with 6-12 sessions of plasmapheresis (plasma exchange or double-filtration plasmapheresis) before transplantation. Splenectomy was also performed on the day of transplantation. Postoperative immunosuppression followed the same regimen as ABO-compatible cases, in which calcineurin inhibitors were initiated 3 days before transplantation, combined with 2 doses of basiliximab. RESULTS Of the 8 patients, 7 subsequently underwent successful living-donor kidney transplantation. Follow-up of our recipients showed that the patient and graft survival rates were 100%. Acute cellular rejection and antibody-mediated rejection episodes occurred in 1 of the 7 recipients. CONCLUSIONS These findings suggest that our immunosuppression regimen consisting of rituximab infusions, splenectomy, plasmapheresis, and pharmacologic immunosuppression may prove to be effective as a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation.

Excellent Outcomes of ABO-Incompatible Kidney Transplantation: A Single-Center Experience

INTRODUCTION Due to the severe shortage of deceased donors in Japan, ABO-incompatible living donor kidney transplantation has been performed since the late 1980s. Excellent long-term outcomes have been achieved; the rates of graft survival among these patients are currently similar to those of recipients of ABO-compatible grafts. Our single-center experience describing the immunosuppressive protocols, complications, and grafts survivals is documented in this study. PATIENTS AND METHODS Among 123 patients with end-stage renal disease who underwent living donor kidney transplantation between January 1999 and December 2010, 25 cases were ABO-incompatible grafts. All of these patients were followed until August 2011. Analyzing these patients, we focused on their immunosuppressive protocols, complications, and graft survivals. RESULTS Patient and graft survival rates were 100%. One patient experienced antibody-mediated rejection and an intractable acute cellular rejection episode, 1 patient an antibody-mediated rejection, and 6 patients had acute cellular rejection episodes. However, there were no severe complications. CONCLUSION Although ABO-incompatible kidney transplantation is a high-risk procedure, a short-term graft survival rate of 100% may be expected due to recent significant improvements in desensitization and recipient management.

Conversion of Stable Kidney Transplant Recipients From a Twice-Daily Prograf to a Once-Daily Tacrolimus Formulation: A Short-Term Study on its Effects on Glucose Metabolism

BACKGROUND The adverse effects of tacrolimus are known to play major roles in posttransplantation diabetes mellitus (PTDM). In the present study, we investigated the effects of conversion from a twice-daily (Tac BID) to a once-daily prolonged release of tacrolimus formulation (Tac OD) on glucose metabolism in stable kidney transplant recipients. PATIENTS AND METHODS In this prospective study, 26 patients converted from Tac BID to the same milligram-milligram daily dose of Tac OD were examined for the effects on renal function, drug trough levels, and glucose metabolism over a 4-week period. RESULTS Conversion from Tac BID to Tac OD on a 1:1 mg basis resulted in a significant decrease in tacrolimus trough levels, but no significant changes in renal function. At 4 weeks after conversion, a homeostasis model assessment of β-cell function, and hemoglobin A1c (HbA1c) decreased significantly. CONCLUSIONS This study demonstrated a significant reduction in tacrolimus trough levels after switching from Tac BID to Tac OD, which increased insulin secretion and decreased HbA1c, suggesting that it may decrease the frequency of PTDM among stable renal transplant recipients.

Clinical outcome of ABO-incompatible living unrelated donor kidney transplantation.

Background: ABO-incompatible living unrelated donor kidney transplantation is an immunologically high-risk procedure, but few reports have been made on the outcomes of these transplants. Patients and Methods: We analyzed 12 kidney transplants using ABO-incompatible living-unrelated donors performed at our institution between January 1999 and December 2007, focusing on the immunosuppressive protocols, complications and graft survivals. Results: Patient and graft survival rates were 100%. One patient experienced antibody-mediated rejection and intractable acute cellular rejection, one had antibody-mediated rejection and one had acute cellular rejection, but their grafts survived after intensive immunosuppressive treatment. There were no severe complications among the recipients. Conclusions: In ABO-incompatible living unrelated donor kidney transplantation, severe rejections may occur due to ABO incompatibility and poor histocompatibility. Therefore, appropriate desensitization, immunosuppression and recipient care are needed for a successful transplant. Recent significant improvements in outcomes indicate that it has become a viable treatment option, given the lack of available donor organs.

Conversion of stable ABO-incompatible kidney transplant recipients from mycophenolate mofetil with standard exposure calcineurin inhibitors (CNIs) to everolimus with very low exposure CNIs–a short-term pilot study

A recent report has demonstrated that as with mycophenolate mofetil (MMF), everolimus is capable of inhibiting human B‐lymphocyte function and activation including B‐lymphocyte proliferation, apoptosis, and immunoglobulin production in vitro. Everolimus may therefore be used as an immunosuppressant in ABO‐incompatible kidney transplantation.

Association between chronic kidney disease and small residual urine volumes in patients with benign prostatic hyperplasia

Aim:  It has been well described that large residual urine volumes (≥300 mL) affect renal function in advanced benign prostatic hyperplasia (BPH). However, it is not clear whether small residual urine volumes (<100 mL) are related to renal function. The present study was performed to examine the association between chronic kidney disease (CKD) and the post‐void residual urine volume (PVR) in BPH patients.

Effects of Conversion From a Twice-Daily Tacrolimus to a Once-Daily Tacrolimus on Glucose Metabolism in Stable Kidney Transplant Recipients

INTRODUCTION The adverse effects of tacrolimus are known to play major roles in new-onset diabetes after transplantation. The purpose of this study was to investigate the effects of conversion from a twice-daily tacrolimus (Tac-BID) to a once-daily tacrolimus (Tac-OD) on glucose metabolism in stable kidney transplant recipients. PATIENTS AND METHODS Twenty-six patients were converted from Tac-BID to Tac-OD on a 1:1 mg basis and examined for its effects on glucose metabolism. Unless rejection or tacrolimus toxicity was suspected, we did not perform dose adjustments of Tac-OD or reconversion to Tac-BID until 4 weeks after conversion. Subsequent dose adjustments were allowed to maintain tacrolimus target trough concentration within the. Changes in clinical parameters were compared between baseline and 24 weeks after conversion. RESULTS Conversion from Tac-BID to Tac-OD on a 1:1 mg basis resulted in a significant decrease in tacrolimus trough level at 4 weeks after conversion. Because dose adjustments were performed, the trough level did not differ significantly between baseline and 24 weeks after conversion. At 4 and 24 weeks after conversion, the homeostasis model assessment of pancreas β-cell function (HOMA-β) increased significantly. CONCLUSIONS Although there was no change in tacrolimus trough level between baseline and 24 weeks after transplantation, HOMA-β at 24 weeks after conversion was significantly higher than that at baseline. These results indicated that conversion from Tac-BID to Tac-OD may improve pancreas β-cell function in kidney transplant recipients.

Late-onset neutropenia and acute rejection in ABO-incompatible kidney transplant recipients receiving rituximab and mycophenolate mofetil

INTRODUCTION Using rituximab, we have performed successful ABO-incompatible kidney transplantations in recipients without splenectomy as well as in those with high pretransplant anti-A/B antibody titers. A common and increasingly recognized toxicity of rituximab is late-onset neutropenia (LON), defined as unexplained grades III to IV neutropenia occurring at least 4weeks after the last dose of rituximab in the absence of an alternative explanation. PATIENTS AND METHODS Between May 2006 and December 2011, 25 patients who received rituximab underwent successful ABO-incompatible kidney transplantation and were enrolled as the subjects in this study. The incidence rate and clinical features of LON as well as the relationship between LON and acute rejection in these patients were studied. RESULTS Twelve recipients (48%) experienced LON 2 to 12months after transplantation. Five of the 12 patients (41.6%) who developed LON had an episode of biopsy-confirmed acute cellular rejection, as compared with one of the 13 patients (7.7%) who did not develop LON. Moreover, 3 patients who experienced LON developed steroid and deoxyspergualin-resistant acute cellular rejection requiring OKT-3 administration. CONCLUSIONS The frequency of acute cellular rejection was higher in ABO-incompatible kidney transplant recipients with LON than in those without LON. Our findings suggested that these recipients who developed LON after rituximab administration may be at an increased risk for acute cellular rejection.

Glucose intolerance in renal transplant recipients is associated with increased urinary albumin excretion

OBJECTIVE New-onset diabetes mellitus after transplantation (NODAT) is a common and serious complication of renal transplantation, and its incidence is known to be increased by immunosuppressive therapy. It has been reported that urinary albumin excretion is a potent predictor of NODAT. This study was conducted to investigate the relationship between glucose intolerance and urinary albumin excretion in renal transplant recipients. METHODS A cross-sectional study of 101 renal transplant recipients without prior evidence of diabetes was conducted. All patients underwent an oral glucose tolerance test with 75g of glucose. RESULTS The patients with glucose intolerance had a significantly greater urinary albumin excretion than those with normal glucose tolerance. Multivariate logistic regression analysis revealed that the increase of urinary albumin excretion correlated significantly with the homeostasis model assessment of insulin resistance and systolic pressure. CONCLUSION These results indicated that glucose intolerance is associated with increased albuminuria in renal transplant recipients. The rise in insulin resistance and systolic pressure may contribute to the increase of urinary albumin excretion in renal transplant recipients.