Long-term Use Of Calcineurin Inhibitors Research Articles

Evaluation of T-Cell Immune Status of Reduced-Dose Cyclosporine and Everolimus Combination Therapy in Kidney Transplant Patients

Kidney transplantation (KT) outcomes have significantly improved with calcineurin inhibitors (CNIs) administration. In recent years, the dose of CNIs has been reduced, and everolimus (EVR) has been used in combination with CNIs to avoid complications from the long-term use of CNIs. However, T-cell immune responses to these protocols have not been fully evaluated. This study evaluated the anti-donor T-cell responses to our CNI-sparing regimen. Fifty-five de novo KT patients were enrolled. Three months after KT, the patients were randomly assigned to either the EVR group, which received low-dose cyclosporine (CsA) (n=28), or the standard-exposure CsA control group (n=27), which was treated with both mycophenolate mofetil and methylprednisolone. Graft function, adverse events, and immunologic status were evaluated 3 years after KT. Mixed lymphocyte reaction (MLR) assays were performed to evaluate anti-donor T-cell responses in KT patients. Both groups maintained graft function well, but total cholesterol levels tended to increase annually in the EVR group. The incidence of cytomegalovirus (CMV) infection tended to be lower in the EVR group, regardless of the CMV serologic status. Immunologic evaluation by MLR assay showed that anti-donor T-cell responses were adequately maintained in both groups. EVR starting 3 months after KT can reduce the trough levels of CsA without affecting graft function or compromising the immunosuppressive effects. The EVR combination protocol is expected to reduce CNI toxicity and improve long-term prognosis after KT.

Development of a mRNA Lipid Nanoparticle (mRNA-LNP) Cancer Vaccine to Prevent Leukemia Relapse after Stem Cell Transplant

Introduction The most common acute leukemia in adults is acute myeloid leukemia (AML). Approximately 20,050 new cases and 11,540 deaths are expected for 2022 in the US. Allogeneic stem cell transplant (alloSCT) remains the only cure for high-risk AML. AlloSCTs leverage the immune system to kill leukemic cells through a graft-versus-leukemia (GVL) response mediated by donor CD4+ and CD8+ T cells that recognize recipient leukemic minor histocompatibility antigens (mHAs) as foreign. Unfortunately, transplantation failure related to relapse is common. We postulate that proper targeting of mHAs could enhance leukemia-specific immune responses without off-target effects, improving relapse rates. Using computational modeling, we predicted a series of GVL mHAs, confirmed our first GVL mHA (UNC-GRK4-V) through targeted mass spectrometry, and generated a high-affinity T cell receptor (TCR) against it. Using UNC-GRK4-V as our target, we developed a novel mHA mRNA lipid nanoparticle (LNP) vaccine that we hypothesized could induce an antigen-specific immune response. Methods A custom mRNA was ordered from TriLink that encoded the UNC-GRK4-V peptide linked to an MHC Class I trafficking domain (MITD) and was modified with a 5' cap and polyadenylated tail. We created mRNA LNPs by mixing an ethanol lipid solution made of ionizable lipid (SS-OP, SM-102, or MC3)/ DOPE/Cholesterol/DMG-PEG 2000 with an aqueous solution of mRNA (eGFP or UNC-GRK4-V mRNA) dissolved in a citrated buffer solution. We measured mRNA LNP sizes with a Malvern ZS90 and quantified encapsulation rates using a Quant-it RiboGreen RNA assay kit. Immature monocyte-derived dendritic cells (mo-DCs) were differentiated from monocytes collected from fresh blood and transfected with mRNA LNPs. As a control, we measured eGFP mRNA LNP transfection rates of mo-DCs using flow cytometry. CD8+ T cells were transduced with a retroviral supernatant containing a high-affinity UNC-GRK4-V T-cell receptor and stimulated. We co-cultured mRNA LNP transfected mo-DCs with transduced CD8+ T cells. IFN-g was measured from the co-culture supernatant using IFN-g ELISA assays. We used flow cytometry to determine the cytotoxic killing of transfected mo-DCs by transduced CD8+ T cells. Results To identify the most efficient ionizable lipid platform for mRNA delivery and transfection, we tested three commercially available ionizable lipids: SS-OP, SM-102, and MC3. We found that all three ionizable lipids were easily reproducible with SS-OP 75.2nm ± SD 14.8, MC3 97.0nm ± SD 5.4, SM-102 102.1nm ± SD 0.651. The encapsulation rates of mRNA were 75.4% ± SD 6.3% for SS-OP, 70.5% ± SD 2.6% for MC3, and 73.7% ± SD 0.1% for SM-102. The transfection rate of mo-DCs using eGFP mRNA LNPs were 0.48%, 19.3%, and 62.5% for SS-OP, MC3, and SM-102, respectively. Based on poor transfection rates with SS-OP, we used MC3 and SM-102 LNP formulations to study cytokine expression and cytotoxic killing using a co-culture model of transfected mo-DC with transduced CD8+ T cells. We found a 16.8-fold increase in IFN-g release for the SM-102 based LNPs compared to control empty LNPs (p < 0.0001) and a 4.1-fold increase in IFN-g release for the MC3 based LNPs compared to control empty LNPs (p < 0.0001). We then evaluated SM-102 LNPs for cytotoxic killing as they demonstrated the highest IFN-g release. SM-102 demonstrated increased cell death of 13.5% versus 3.5% for control (empty SM-102) after being normalized for background mo-DC death. Conclusions The SM-102 based UNC-GRK4-V mRNA LNP vaccine elicits robust, antigen-specific T-cell responses and could be a potent therapeutic for decreasing relapse rates post-alloSCT. Furthermore, advances in alloSCT have created regimens that eliminate traditional long-term calcineurin inhibitor use in post-alloSCT, allowing therapeutic cancer vaccines to be given much earlier after transplant.

Human complete NFAT1 deficiency causes a triad of joint contractures, osteochondromas, and B-cell malignancy

AbstractThe discovery of humans with monogenic disorders has a rich history of generating new insights into biology. Here we report the first human identified with complete deficiency of nuclear factor of activated T cells 1 (NFAT1). NFAT1, encoded by NFATC2, mediates calcium-calcineurin signals that drive cell activation, proliferation, and survival. The patient is homozygous for a damaging germline NFATC2 variant (c.2023_2026delTACC; p.Tyr675Thrfs∗18) and presented with joint contractures, osteochondromas, and recurrent B-cell lymphoma. Absence of NFAT1 protein in chondrocytes caused enrichment in prosurvival and inflammatory genes. Systematic single-cell–omic analyses in PBMCs revealed an environment that promotes lymphomagenesis with accumulation of naïve B cells (enriched for oncogenic signatures MYC and JAK1), exhausted CD4+ T cells, impaired T follicular helper cells, and aberrant CD8+ T cells. This work highlights the pleiotropic role of human NFAT1, will empower the diagnosis of additional patients with NFAT1 deficiency, and further defines the detrimental effects associated with long-term use of calcineurin inhibitors.

Bioenergetic maladaptation and release of HMGB1 in calcineurin inhibitor-mediated nephrotoxicity

Calcineurin inhibitors (CNIs) are potent immunosuppressive agents, universally used following solid organ transplantation to prevent rejection. Although effective, the long-term use of CNIs is associated with nephrotoxicity. The etiology of this adverse effect is complex, and effective therapeutic interventions remain to be determined. Using a combination of in vitro techniques and a mouse model of CNI-mediated nephrotoxicity, we found that the CNIs, cyclosporine A (CsA), and tacrolimus (TAC) share a similar mechanism of tubular epithelial kidney cell injury, including mitochondrial dysfunction and release of High-Mobility Group Box I (HMGB1). CNIs promote bioenergetic reprogramming due to mitochondrial dysfunction and a shift toward glycolytic metabolism. These events were accompanied by diminished cell-to-cell adhesion, loss of the epithelial cell phenotype, and release of HMGB1. Notably, Erk1/2 inhibitors effectively diminished HMGB1 release, and similar inhibitor was observed on inclusion of pan-caspase inhibitor zVAD-FMK. In vivo, while CNIs activate tissue proremodeling signaling pathways, MAPK/Erk1/2 inhibitor prevented nephrotoxicity, including diminished HMGB1 release from kidney epithelial cells and accumulation in urine. In summary, HMGB1 is an early indicator and marker of progressive nephrotoxicity induced by CNIs. We suggest that proremodeling signaling pathway and loss of mitochondrial redox/bioenergetics homeostasis are crucial therapeutic targets to ameliorate CNI-mediated nephrotoxicity.

Calcineurin inhibitors: a double-edged sword.

Recently, research has directed its interests into identifying molecular pathways implicated in calcineurin inhibitor (CNI)-induced renal fibrosis. An emerging body of studies investigating calcineurin (CnA) activity has identified distinct actions of two main ubiquitously expressed isoforms: CnAα and CnAβ. CNIs have the capacity to inhibit both of these CnA isoforms. In the kidney, CnAα is required for development, whereas CnAβ predominantly modulates the immune response and glomerular hypertrophic signaling powered by activation of the transcription factor, nuclear factor of activated T lymphocytes (NFAT). Interestingly, data have shown that loss of CnAα activity contributes to the expression of profibrotic proteins in the kidney. Although this finding is of great significance, follow-up studies are needed to identify how loss of the CnAα isoform causes progressive renal damage. In addition, it is also necessary to identify downstream mediators of CnAα signaling that assist in upregulation of these profibrotic proteins. The goal of this review is to provide insight into strides taken to close the gap in elucidating CnA isoform-specific mechanisms of CNI-induced renal fibrosis. It is with hope that these contributions will lead to the development of newer generation CNIs that effectively blunt the immune response while circumventing extensive renal damage noted with long-term CNI use.

Randomized Sirolimus-based Early Calcineurin Inhibitor Reduction in Liver Transplantation: Impact on Renal Function.

The long-term use of calcineurin inhibitors (CNIs) after liver transplantation (LT) is associated with nephrotoxicity. Five-year follow-up data were retrieved from the randomized controlled multicenter SiLVER trial. Standard CNI-based mammalian target of rapamycin-free immunosuppression (group A, n = 264) was compared with a 50% reduction of CNI and introduction of the mammalian target of rapamycin inhibitor Sirolimus (SIR) within 4-6 weeks after LT (group B, n = 261). Median MELD at LT was low with 10 (7-15) (group A) and 11 (8-15) (group B) in the intention-to-treat approach. CNI dose and CNI trough were reduced by 20% and 8% (group A) versus 55% and 56% (group B) at 3 months posttransplantation. Renal function was preserved at 3 months after LT in the SIR arm (estimated glomerular filtration rate 74 [57-95] versus 67 [55-85] mL/min/1.73m2 P = 0.004) but was similarly impaired thereafter compared with group A. The per protocol analysis identified LT recipients in group B with concomitant early CNI minimization and SIR treatment ≥ year 1 with significantly superior estimated glomerular filtration rate and lowest rate of chronic kidney disease (≥stage 3) from year 1 onwards until study end. Competing risk factors for renal disease (arterial hypertension, fat metabolism disorder, and hyperglycemia) were not associated with worse kidney function. Prevention of CNI nephrotoxicity by SIR-based early CNI minimization protects renal function only short-term after LT in the intention-to-treat analysis of this low MELD cohort. Yet, selected LT recipients compliant with early CNI minimization and SIR maintenance achieved better long-term renal outcomes compared with real-world practice.

Th1, Th2, Th17 cell subsets in two different immunosuppressive protocols in renal allograft recipients (Sirolimus vs mycophenolate mofetil): A cohort study

Long-term use of calcineurin inhibitors (CNI) is associated with nephrotoxicity, which is an important cause of renal dysfunction. Therefore, CNI-minimization strategies which decrease the CNI nephrotoxicity under the protection of additional immunosuppressant drugs have been developed. The aim of current cohort study was to compare the effect of two immunosuppressive protocols [tacrolimus (TAC) in combination with mycophenolate mofetil (MMF) and prednisolone (PRED) versus TAC in combination with sirolimus (SRL) and prednisolone] on the frequency of T helper cell subsets (Th1, Th2 and Th17 cells) and their associated cytokine (IFN-γ, IL-4 and IL-17A) levels in renal allograft recipients.In this study, renal transplant recipients who received induction therapy (Antithymocyte globulin) and were also on triple immunosuppressive therapy were included and divided in to two groups: Group A was comprised 14 patients who received TAC, MMF and PERD whereas group B was composed of 10 patients who received TAC, SRL and PERD. The frequency of Th1, Th2 and Th17 cells in the peripheral blood mononuclear cells (PBMCs) of the patients was analyzed by flow cytometry before and 4 months after transplantation. In addition, IFN-γ, IL-4 and IL-17A concentrations in PBMC culture supernatants of patients before and 4 months after transplantation were quantified by ELISA.The results of our study showed that TAC, MMF and PRED protocol did not diminish the frequency of Th17 cells at 4 months post-transplantation (5% ± 2.5) compared with pre-transplantation (2.3% ± 1; P < 0.05). However, Th17 (3.6% ± 1.5 pre-transplantation vs 2.2% ± 0.9 at 4 months post-transplantation; P < 0.05), Th2 (1.4% ± 0.3 pre-transplantation vs 0.8% ± 0.4 at 4 months post-transplantation; P < 0.05) cell subsets and IL-4 concentration (71.5 pg/ml ± 12 pre-transplantation vs 62.5 pg/ml ±4.4 at 4 months post-transplantation; P < 0.05) were significantly decreased after transplantation in patients who had received SRL, TAC and PRED.In conclusion, the data of the current study suggest that using reduced dose of TAC in SRL, TAC and PRED protocol is in favor of allograft survival; however a cohort study with larger sample size is needed for confirming our results.

Belatacept in Solid Organ Transplant: Review of Current Literature Across Transplant Types.

Calcineurin inhibitors (CNIs) have been the backbone immunosuppressant for solid organ transplant recipients for decades. Long-term use of CNIs unfortunately is associated with multiple toxicities, with the biggest concern being CNI-induced nephrotoxicity. Belatacept is a novel agent approved for maintenance immunosuppression in renal transplant recipients. In the kidney transplant literature, it has shown promise as being an alternative agent by preserving renal function and having a minimal adverse effect profile. There are emerging studies of its use in other organ groups, particularly liver transplantation, as well as using with other alternative immunosuppressive strategies. The purpose of this review is to analyze the current literature of belatacept use in solid organ transplantation and discuss its use in current practice.

Mini-review of kidney disease following hematopoietic stem cell transplant .

Advancements in hematopoietic cell transplantation (HCT) have broadened indications for its use and resulted in more long-term survivors. Stem cell transplantation is associated with several well-known toxicities, although renal complications are not well defined. Acute and chronic kidney disease remains a common complication following transplantation itself. Incidence and risk factors for the development of chronic kidney disease (CKD) is less well understood. Recent estimates suggest that nearly 15% of subjects undergoing HCT will develop CKD, a complication that can progress to end-stage renal disease (ESRD), disrupts overall quality of life, and reduces overall survival. Several commonly-reported risk factors include acute kidney injury, graft-versus-host disease, and long-term calcineurin inhibitor use. This review highlights the incidence, timeline, etiology, risk factors, and prognosis of kidney disease in the setting of hematopoietic stem cell transplantation. Investigation of the causes of CKD is needed, as are ways to prevent, mitigate, and treat kidney injury. Renal disease importantly reflects prognosis, with dialysis-requiring patients carrying greater than 80% mortality after 3 years. Although CKD following HCT is common, prospective studies are needed to confirm risk factors and better define the underlying mechanisms in order to promote therapies that prevent this complication.

Evaluating the efficacy, safety and evolution of renal function with early initiation of everolimus-facilitated tacrolimus reduction in de novo liver transplant recipients: Study protocol for a randomized controlled trial.

BackgroundIntroduction of calcineurin inhibitors had led to improved survival rates in liver transplant recipients. However, long-term use of calcineurin inhibitors is associated with a higher risk of chronic renal failure, neurotoxicity, de novo malignancies, recurrence of hepatitis C viral (HCV) infection and hepatocellular carcinoma. Several studies have shown that everolimus has the potential to provide protection against viral replication, malignancy, and progression of fibrosis, as well as preventing nephrotoxicity by facilitating calcineurin inhibitor reduction without compromising efficacy. The Hephaistos study evaluates the beneficial effects of early initiation of everolimus in de novo liver transplant recipients.Methods/DesignHephaistos is an ongoing 12-month, multi-center, open-label, controlled study aiming to enroll 330 de novo liver transplant recipients from 15 centers across Germany. Patients are randomized in a 1:1 ratio (7–21 days post-transplantation) to receive everolimus (trough levels 3–8 ng/mL) with reduced tacrolimus (trough levels <5 ng/mL), or standard tacrolimus (trough levels 6–10 ng/mL) after entering a run-in period (3–5 days post-transplantation). In the run-in period, patients are treated with induction therapy, mycophenolate mofetil, tacrolimus, and corticosteroids according to local practice. Randomization is stratified by HCV status and model of end-stage liver disease scores at transplantation. The primary objective of the study is to exhibit superior renal function (estimated glomerular filtration rate assessed by the Modification of Diet in Renal Disease (MDRD)-4 formula) with everolimus plus reduced tacrolimus compared to standard tacrolimus at Month 12. Other objectives are: to assess the incidence of treated biopsy-proven acute rejection, graft loss, or death; the incidences of components of the composite efficacy endpoint; renal function via estimated glomerular filtration rate using various formulae (MDRD-4, Nankivell, Cockcroft-Gault, chronic kidney disease epidemiology collaboration and Hoek formulae); the incidence of proteinuria; the incidence of adverse events and serious adverse events; the incidence and severity of cytomegalovirus and HCV infections and HCV-related fibrosis.DiscussionThis study aims to demonstrate superior renal function, comparable efficacy, and safety in de novo liver transplant recipients receiving everolimus with reduced tacrolimus compared with standard tacrolimus. This study also evaluates the antiviral benefit by early initiation of everolimus.Trial registrationNCT01551212.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-015-0626-0) contains supplementary material, which is available to authorized users.

Beraprost Sodium (Prostaglandin I2 analogue) Delays Deterioration of allograft Dysfunction in Kidney Transplant Recipient Treated With Calcineurin Inhibitors.

Purpose: Calcineurin inhibitors(CNIs) have considerably improved renal allograft survival. However, long-term use of CNIs can cause nephrotoxicity. The purpose of this study was to evaluate the effect of beraprost sodium(prostaglandin I2 analogue) on renal allograft in patients treated with CNIs. Methods: In this prospective, open-label, comparative, single center study, 40 patients who underwent first kidney-only transplants were included. They were divided randomly into two groups: control and treatment group. The patients in treatment group received beraprost sodium(120μg/day) for a year. The changes of estimated glomerular filtration rate(eGFR), blood pressure, and histologic results were compared between two groups. Results Ninteen patients in treatment group and 14 patients in control group completed the study. All, except one patient in control group treated cyclosporine, were treated with tacrolimus and the trough levels were in the range of 4.8-5.8ng/ml. The decline in eGFR was significantly lower in treatment group than that of control(62.9±14.15 to 61.8 ±14.96, vs. 68.8±15.31 to 62.8±15.17ml/min/1.73m2,P=0.048). The changes of blood pressure did not differ between two groups. From histologic results, the mean scores for arteriolar hyaline were decreased in treatment group and progressed in control group, however, the differences could not reach the statistical differences(0.21±0.535 to 0.11±0.315 vs. 0 to 0.14±0.363,P=0.105). The mean scores for interstitial fibrosis and tubular atrophy(IFTA), glomuerulosclerosis were not significantly different between two groups. However, the proportion of patients with IFTA score higher than one was increased in control and maintained in treatement group. The scores for epithelial-mesenchymal transition markers(vimentin, ß-catenin) were decreased in treatment group and progressed in control group, however, the differences could not reach the statistical differences. Conclusions Beraprost sodium has a beneficial effect on renal allograft function in patients exposed to CNIs. However, the change of structural damage is not obvious with the conditions of low levels of CNIs and short-term use of beraprost sodium. Further follow-up is needed to demonstrate the changes of structural damage.

Impact of Early Everolimus-Facilitated Reduction or Elimination of Tacrolimus on the Evolution of Renal Function in 719 De Novo Liver Transplant Recipients: 12 Month Data of the H2304 Study

Background: Long-term use of calcineurin inhibitors (CNI; cyclosporine and tacrolimus [TAC]) is associated with chronic renal dysfunction, a significant cause of morbidity in liver transplant recipients (LTxR). Early everolimus (EVR) facilitated reduction or elimination of CNI may reduce CNI-associated nephrotoxicity in de novo LTxR. Methods: H2304 (NCT00622869) is a 24-month (M), randomised, multicenter, open-label study in 719 de novo LTxR. After 30 days with TAC±mycophenolic acid, LTxR were randomised 1:1:1 into 3 arms comparing (1) EVR (C0 3-8ng/mL)+ reduced TAC (C0 3-5ng/mL; EVR+rTAC; N=245) or (2) EVR (C0 6-10ng/mL)+TAC withdrawal (TAC-WD; N=231) at M4 to (3) standard TAC (C0 6-10ng/mL; TAC-C; N=243); all with steroids. Main endpoints at M12 included the composite efficacy failure rate of treated BPAR, graft loss or death and evolution of renal function (RF) from randomisation (RND) to M12 measured as eGFR (MDRD4; mL/min/1.73m2). Results: Enrollment in TAC-WD arm was stopped early due to high AR rate clustered around time of TAC elimination; statistical comparison is only presented for EVR+rTAC vs TAC-C. At M12, the composite efficacy failure rate in EVR+rTAC arm was comparable to TAC-C (6.7 vs 9.7%, p=0.230); however, was higher in TAC-WD (24.2%). Evolution of RF from RND to M12 was superior for EVR+rTAC over TAC-C (adjusted mean difference [SE] in eGFR: +8.50mL/min/1.73m2 [2.12], 97.5% CI [3.74, 13.27]; p< 0.001); difference for TAC-WD vs TAC-C was +9.22mL/min/1.73m2 [2.15]. Superior mean eGFR with EVR+rTAC vs TAC-C was achieved at M2 post LTx and maintained until M12 (all time points p< 0.001; Figure). In LTxR remaining on the assigned treatment, mean eGFR (mL/min/1.73m2) at M12 was EVR+rTAC: 81.4 (N=172) vs TAC-C: 71.2 (N=177), p< 0.001; TAC-WD: 90.9 (N=90). Proportion of patients with decline in eGFR from RND to M12 was significantly less for EVR+rTAC (13 %) vs TAC-C (21.4%; p=0.01); TAC-WD (14.7%). More patients on EVR +rTAC (15.4% vs. 9.6%) shifted to better eGFR categories at M12 and fewer patients had decline in eGFR vs TAC-C (10.7% vs 23.4%). Mean eGFR at M12 by eGFR category at RND showed that EVR+rTAC patients had better eGFR vs TAC-C for eGFR categories 30-≤45, 45-≤60, 60-≤90, and ≥90 with significantly higher eGFR for 60-≤90 (p=0.001) and ≥90 (p< 0.0001); TAC-WD patients had higher eGFR vs TAC-C for all the above categories. Mean urinary protein/creatinine ratio for EVR+rTAC was 245.7mg/g vs 151.2mg/g in TAC-C (p=0.008); TAC-WD: 237.2mg/g.[Figure]Conclusions: Early EVR introduction at 1M post LTx allowed substantial TAC reduction with superior RF compared to standard TAC without compromising efficacy in de novo LTxR at M12. TAC withdrawal achieved further RF benefit although insufficient efficacy.

“Tac”kling a Difficult Problem

“Tac”kling a Difficult Problem

Peritoneal Dialysis after Nonrenal Solid Organ Transplantation: Clinical Outcomes and Practical Considerations

The incidence of end-stage renal disease following nonrenal solid organ transplantation (NRSOT) is increasing and is associated with a poor prognosis. The etiology of end-stage renal disease is multifactorial, with calcineurin inhibitor (CNI) nephrotoxicity being primarily responsible. The impact of dialysis modality on the survival of these patients remains unclear. Peritoneal dialysis appears to be a feasible and safe option for renal replacement therapy in NRSOT patients. Concerns that NRSOT patients are at a higher risk of infectious and noninfectious complications necessitate practical considerations when prescribing and planning for peritoneal dialysis in these patients. While nephrotoxicity is a well-recognized complication of long-term CNI use, "peritoneotoxic" effects with significant alterations in peritoneal membrane structure and function have recently been described. Further study including the role of CNI-free immunotherapy protocols to optimize the outcomes of NRSOT recipients is needed.

Timing of sirolimus conversion influences recovery of renal function in liver transplant recipients

The long-term use of calcineurin inhibitors (CNI) leads to renal dysfunction in many liver transplant (LT) recipients. The purpose of this analysis is to evaluate renal function in patients converted from CNI to sirolimus (SRL). From May 2002-November 2006, 137 LT were performed in 125 patients, 72 of which were converted to SRL. Evaluation of SRL conversion was stratified by early conversion (<90 d from LT) (EC) vs. late conversion (LC). Renal function was evaluated using the six-point modification of diet in renal disease formula (estimated glomerular filtration rate [eGFR]). Forty-two patients on SRL and 40 on CNI had at least three months of follow-up and are included in the eGFR evaluation. At all time points after conversion, the EC group demonstrated a significantly higher mean eGFR than those in the LC group. A significant improvement in eGFR was seen within the EC group when comparing eGFR at time of conversion to eGFR at three, six, nine, and 12 months after conversion and last follow-up. The only improvement in the LC group was from conversion to the three-month time point. We conclude that EC to SRL results in a profound improvement in eGFR that begins at three months and is sustained beyond one yr.

Calcineurin Inhibition and Development: Insights from Research Models

Because of its role in the T cell response, pharmacological inhibition of calcineurin is clinically useful to suppress the immune system following organ transplantation. Introduction of calcineurin inhibitors (CIs) in the early 1980s resulted in a profound improvement in graft survival. For this reason, calcineurin inhibitors have become a cornerstone for post-transplant management. CIs are also used to treat an increasingly wide array of immune-related disorders. However, inhibition of calcineurin is known to affect tissues other than the immune system and long-term use of CIs often produces therapeutically-limiting side-effects; the most common of which is nephrotoxicity. An additional complex issue arises with the use of CI during pregnancy as the role of calcineurin in development is still incompletely understood. Survey of the literature reveals a growing number of studies demonstrating direct links between calcineurin action and development, particularly of the immune system and kidney structures. Data thus far point to important roles for calcineurin in regulation of transcription, cell hypertrophy, extracellular matrix accumulation, and apoptosis effectively linking observed therapeutic side-effects with direct actions of calcineurin in immune and renal cells. Thus, it seems prudent to review what is known about calcineurin inhibition in animal models with an emphasis on developmental affects and to then compare with the albeit limited data available from human subjects. Just as laboratory research is demonstrating mechanistic explanations for some features of calcineurin inhibitor nephrotoxicity, so to may laboratory results yield important information about the contribution of calcineurin to development. Keywords: Cyclosporin A, development, calcineurin knockout

Contemporary Concepts in Prevention and Treatment of Cardiac Allograft Vasculopathy

Cardiac allograft vasculopathy (CAV), is characterized by heterogeneous proliferative thickening of the vascular intima of the cardiac allograft vasculature. Since its presentation is commonly clinically silent, early diagnosis and preventative therapy are critical. Preventative therapy including optimization of immunosuppressive therapy and treatment of comorbidities associated with CAV progression must be initiated early since most of the intimal thickening occurs during the first year posttransplant. Long-term use of calcineurin inhibitors is associated with a high incidence of chronic renal disease and also contributes to hyperlipidemia and hypertension, all of which may exacerbate CAV. In addition, statins, antihypertensive agents and anti-CMV agents all have demonstrated benefits in reducing CAV. Once established, the limited treatment options include nonpharmacologic interventions such as retransplantation, percutaneous coronary interventions, coronary artery bypass grafting, transmyocardial laser revascularization and heparin-induced/mediated extracorporeal LDL plasmapheresis (HELP). As the use of new assessment tools increases our understanding of this disease, better preventative and treatment strategies are evolving.

Chronic Kidney Disease Following Non-Myeloablative Hematopoietic Cell Transplantation

Chronic kidney disease (CKD) following myeloablative allogeneic hematopoietic cell transplantation (HCT) occurs in 20% of survivors at 1 year and is believed to be due to radiation nephritis. Non-myeloablative allogeneic HCT is a recent procedure that employs significantly lower doses of chemoradiotherapy, however, incidence and risk factors for CKD following non-myleoablative HCT have not been defined. We performed a retrospective cohort study of 122 patients from three institutions who were available for analysis at 6 months following non-myeloablative HCT. Patients received two Gy of radiation; 62% received fludarabine as preconditioning. CKD was defined as at least a 25% reduction in glomerular filtration rate (GFR) from baseline using the abbreviated modified diet in renal disease (MDRD) equation. Eighty-one of 122 patients (66%) showed evidence of CKD at follow-up. Multivariate analysis revealed that acute renal failure (ARF) during the first 100 days post-transplant was associated with development of CKD (Adjusted OR 32.8 with 95% CI 4.3-250) after controlling for other variables. Previous autologous HCT, long-term calcineurin inhibitor use and extensive chronic GVHD were independently associated with CKD. CKD following non-myeloablative HCT appears to be a distinct clinical entity and likely not related to radiation nephritis. Future research should focus on possible mechanisms for alleviating chronic injury and decreasing use of calcineurin inhibitors.

SIROLIMUS IN HEART TRANSPLANTATION: A STRATEGY TO IMPROVE RENAL FUNCTION AND REDUCE THE RISK OF RENAL FAILURE

P625 Aims: The predominant cause of chronic renal disease after heart transplantation is the long-term use of calcineurin inhibitors (CI)-either cyclosporine or tacrolimus. Sirolimus (S) has been administered successfully in the management of this complication in other solid organs recipients. We report our experience with (S) administered with low doses of CI or as primary therapy in combination with steroids and mycophenolate mophetil (MM) in heart transplant recipients who developed renal insufficiency after transplantation. Methods: Fifty four (54) patients (pts) have received an orthotopic heart transplant in the Puerto Rico Heart Transplant Program since June 1999 to March 2004. The initial immunosuppressive regimen consisted of MM, steroids, and a CI (50 cyclosporine and 2 tacrolimus). Renal function was monitored closely with creatinine clearance (CC) determination each 3-6 months. If CC decreased below 49 ml/min per 1.73 Kgs per M2, the CI dosage was reduced to the minimal dose to control rejection and CC was reexamined. If renal function remained unchanged, (S) was started, MM discontinued and CI dose reduced in 50% (Group I). After this approach, if CC continued < 49 ml/min CI was discontinued, MM restarted and (S) was continued, (Group II). Results: Among 54 pts, 41males, 13 females, mean age 47 years (11 to 62 years), 20 (37%) has diabetes mellitus (DM), and 34 (63%) hypertension. None had acute perioperative renal failure or hepatitis C, and all were receiving either an ACE inhibitor or an ARB agent. In twenty (20) pts, (S) was introduced in its immunosuppressive regime to manage renal insufficiency (CC<49 mls/min). Ten (10) required (S), low dose CI, plus prednisone (Group I); and ten (10) (S), MM, plus prednisone (Group II), at a mean time of 22 months post transplantation. The average CC increased from 38.6 mls/min to 63.5 mls/min (p<0.05) in Group I, and from 38.4 mls/min to 67.4 mls/min (p<0.5) in Group II after (S) administration. No significant change in left ventricular ejection fraction, or in episodes of rejection were observed since one year before and one year after Sirolimus. None of our patients has required renal dialysis. Renal function improvement sustained one year after Sirolimus (S) in heart transplant patients: Conclusions: Our heart transplant recipients have a high incidence of DM, and renal insufficiency with CC < 49mls /min, post transplant in 37%; and 38% respectively. Sirolimus has offered a flexible opportunity to manage this complication. Either in combination with a CI at lower doses (50% dose reduction) or as a substitution therapy for the CI, we have observed a significant improvement in renal function with Sirolimus without graft function deterioration or increase in rejection.Figure

Mycophenolate mofetil monotherapy in liver transplant recipients: a single center experience.

The long-term use of calcineurin inhibitors (CIs) is associated with significant morbidity in liver transplant recipients. Although mycophenolate mofetil (MMF) is well tolerated, two small studies reported an unacceptable rate of acute allograft rejection in liver transplant recipients receiving MMF monotherapy. In this study, we retrospectively investigated the safety and efficacy of MMF monotherapy in liver transplant recipients. We reviewed the medical records of all patients who underwent liver transplant at our institution. Sixteen patients were identified who received MMF either as monotherapy (n = 13) or with corticosteroids (n = 3; 2 of them for other comorbid conditions), and these patients were studied to determine the efficacy and complications. Fifteen (15/16) patients were converted from a CI to MMF because of renal insufficiency. Patients were converted to MMF monotherapy after a median of 2,056 days (range, 606-5,893) after liver transplantation. The median postconversion follow-up was 668 days (range, 60-1,509). Four patients required dialysis despite conversion; of those patients not requiring dialysis, serum creatinine stabilized and showed a trend toward improvement (2.51 +/- 1.12 mg/dL to 1.85 +/- .58 mg/dL, P = .1). However, there were 3 episodes (47, 107, and 1,203 days after conversion) of severe, irreversible allograft rejection after conversion resulting in death in 2 patients and necessitating retransplantation in 1 patient. There were no patient characteristics, except perhaps African-American race, that predicted the development of rejection. In conclusion, MMF monotherapy was associated with a significant risk (19%) of unpredictable, severe, and irreversible allograft rejection even among long-term transplant survivors. Caution should be exercised before converting patients to MMF monotherapy.