Hemangshu Podder

Risk factors for impaired wound healing in sirolimus‐treated renal transplant recipients

Abstract:  Aim:  As sirolimus has been implicated in impaired wound healing, the aim of this study was to evaluate risk factors for wound complications after renal transplantation in patients treated with this drug de novo.

BK virus-associated nephropathy in sirolimus-treated renal transplant patients : Incidence, course, and clinical outcomes

Background. Because the course of polyoma virus–associated nephropathy (PVAN) has not been evaluated in a large cohort of patients receiving sirolimus (SRL)-based regimens, we have herein presented the incidence, clinical characteristics, and outcomes of 378 renal transplant recipients treated with SRL-based immunosuppression. Methods. This retrospective single center study evaluated 344 kidney alone (KTX) and 34 simultaneous pancreas-kidney (SPK) transplantations performed between June 2000 and December 2004. Results. At a mean follow-up of 43.3 months, six kidney (1.7%) and three kidney-pancreas (9.0%) transplanted patients displayed biopsy-proven PVAN. The mean time to diagnosis after transplantation was 18.2 months (range: 3.5–31.1 months), with a higher incidence among patients exposed (4.23%) versus not exposed to rabbit antithymocyte globulin (rATG; 0.53%; P=0.019) or SPK (9.0%) versus KTX (1.7%) recipients (odds ratio: 5.43; confidence interval: 1.29–22.8; P=0.038). Despite treatment with cidofovir, reduced immunosuppression and maintenance therapy with no agents other than SRL (C0=10.2±2.7 ng/dL) plus modest doses of prednisone (≤5 mg), five patients (55.5%) experienced renal allograft failure. No rejection episodes were documented during the PVAN treatment and pancreatic function continued to be excellent among the SPK patients. Conclusions. Patients treated with SRL-based immunosuppression showed an incidence at the lower end of the range described with various other contemporaneous immunosuppressive regimens and with other cohorts not undergoing BK virus polymerase chain reaction surveillance. Exposure to rATG and SPK transplantation represented risk factors for the occurrence of PVAN, which showed a pernicious course despite withdrawal of calcineurin antagonists and/or mycophenolate mofetil.

The selective use of basiliximab versus thymoglobulin in combination with sirolimus for cadaveric renal transplant recipients at low risk versus high risk for delayed graft function.

Background. We previously reported that the use of basiliximab together with sirolimus permits a window of recovery from delayed graft function before the introduction of reduced-dose cyclosporine. The present study reviews our experience with the substitution of thymoglobulin for basiliximab as induction therapy for recipients at increased risk for early acute rejection episodes. Methods. We retrospectively reviewed 145 cadaveric renal allograft recipients who received either basiliximab (n=115) or thymoglobulin (n=30) in combination with sirolimus and prednisone, followed by delayed introduction of reduced doses of cyclosporine. Recipients were stratified as high immune responders if they were African American, a retransplant recipient, or a recipient with a panel-reactive antibody greater than 50%. All other recipients were considered low immune responders. Results. Basiliximab-treated high immune responders exhibited a higher incidence of acute rejection episodes (26%) than either basiliximab-treated low immune responders (10%, P=0.04) or thymoglobulin-treated high immune responders (3%, P=0.01). The median time to initiation of cyclosporine was 12 days; cyclosporine was initiated when the serum creatinine level was 2.5 mg/dL or less. Patients with early return of renal function displayed a lower incidence of acute rejection episodes than those with later recovery of function (P=0.003). High immune responders treated with basiliximab expressed a higher mean serum creatinine level at 3 months (P<0.01), 6 months (P=0.02) and 12 months (P=0.01) than either low immune responders treated with basiliximab or high immune responders treated with thymoglobulin. Conclusion. A strategy combining sirolimus with basiliximab for low-immunologic risk recipients and thymoglobulin for high-risk recipients leads to prompt recovery of renal function with a low risk of acute rejection episodes.

Janus kinase 3: a novel target for selective transplant immunosupression

Existing immunosuppressants inhibit lymphocyte activation and T cell cytokine signal transduction pathways, reducing the rate of acute rejection episodes to < 10%. However, the widespread tissue distribution of their molecular targets engenders pleiotropic toxicities. One strategy to address this problem seeks to identify compounds that selectively inhibit a target restricted in distribution to the lymphoid system. Janus kinase (Jak) 3 is such a molecule; it mediates signal transduction via the gamma common chain of lymphokine surface receptors. Disruption of this lymphoid-restricted enzyme would not be predicted to produce collateral damage in other organ systems. Development of selective Jak3 inhibitors has been difficult due to crossreactivity with its homologue, Jak2. In contrast to all other putative antagonists, which are discussed in detail herein, one Jak3 inhibitor, NC1153, shows at least 40-fold greater selective inhibition for Jak3 than for Jak2, is robustly synergistic with calcineurin antagonists, and, either alone or in combination with cyclosporin, produces no adverse effects in rodents preconditioned to be at heightened risk for nephrotoxicity, bone marrow suppression, or altered lipid metabolism.

The Mannich Base NC1153 Promotes Long-Term Allograft Survival and Spares the Recipient from Multiple Toxicities

JAK3 is a cytoplasmic tyrosine kinase with limited tissue expression but is readily found in activated T cells. Patients lacking JAK3 are immune compromised, suggesting that JAK3 represents a therapeutic target for immunosuppression. Herein, we show that a Mannich base, NC1153, blocked IL-2-induced activation of JAK3 and its downstream substrates STAT5a/b more effectively than activation of the closely related prolactin-induced JAK2 or TNF-α-driven NF-κB. In addition, NC1153 failed to inhibit several other enzymes, including growth factor receptor tyrosine kinases, Src family members, and serine/threonine protein kinases. Although NC1153 inhibited proliferation of normal human T cells challenged with IL-2, IL-4, or IL-7, it did not block T cells void of JAK3. In vivo, a 14-day oral therapy with NC1153 significantly extended survival of MHC/non-MHC mismatched rat kidney allografts, whereas a 90-day therapy induced transplantation tolerance (>200 days). Although NC1153 acted synergistically with cyclosporin A (CsA) to prolong allograft survival, it was not nephrotoxic, myelotoxic, or lipotoxic and did not increase CsA-induced nephrotoxicity. In contrast to CsA, NC1153 was not metabolized by cytochrome P450 3A4. Thus, NC1153 prolongs allograft survival without several toxic effects associated with current immunosuppressive drugs.

Selectin Inhibitor Bimosiamose Prolongs Survival of Kidney Allografts by Reduction in Intragraft Production of Cytokines and Chemokines

Binding of the P-, L-, and E-selectins to sialyl Lewis(x) (sLe(x)) retards circulating leukocytes, thereby facilitating their attachment to the blood vessels of allografts. Whether the selectin inhibitor bimosiamose (BIMO; C(46)H(54)O(16) . 0.25 H(2)O [867.4 molecular weight]) inhibits the rejection process of kidney allografts in a rat model was examined. Rat recipients acutely rejected kidney allografts at a mean survival time of 8.8 +/- 0.75 d. An intravenous 7-d infusion by osmotic pump of 2.5, 5, 10, or 20 mg/kg BIMO extended kidney allograft survival to 11.5 +/- 2.2 d (P < 0.03), 25.4 +/- 11.4 d (P < 0.006), 37.4 +/- 13.6 d (P < 0.001), and 39.8 +/- 34.5 d (P < 0.01), respectively. Combination of BIMO with cyclosporine produced synergistic interactions, as documented by the combination index (CI) values of 0.34 to 0.43 (CI <1 is synergistic; CI = 1 is additive; and CI >1 is antagonistic). Similarly, BIMO interacted synergistically with sirolimus (CI = 0.64) and FTY720 (CI = 0.22). While the mechanism of immunosuppression was being analyzed, decreased infiltration of CD4(+), CD8(+), and macrophages on day 7 after grafting was observed. Multiple cytokines were also expressed, including IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, IL-18, TNF-alpha, and IFN-gamma in kidney allografts on days 3, 5, and 7 after grafting, as measured by a ribonuclease protection assay. Furthermore, at similar time points, BIMO treatment reduced intragraft expression of P-selectin glycoprotein ligand-1, CX(3)CL1, CCL19, CCL20, and CCL2. Thus, BIMO blocks allograft rejection by reduction of intragraft expression of cytokines and chemokines.

Thymoglobulin, sirolimus, and reduced-dose cyclosporine provides excellent rejection prophylaxis for pancreas transplantation

Background. We investigated a novel immunosuppressive protocol including thymoglobulin induction in combination with sirolimus and corticosteroids, followed by introduction of markedly reduced exposures to cyclosporine to prevent pancreas-transplant rejection. Methods. A 7-day course of thymoglobulin (1.5 mg/kg per day) was begun on postoperative day (POD) 0, together with 15 mg of sirolimus on POD 1, and followed by 5 mg per day, targeting these doses to achieve a trough of 10 to 20 ng/mL. When the serum creatinine was below 2.5 mg/dL, cyclosporine was introduced at 50 mg twice daily with dose adjustment to maintain a trough concentration of 100 to 125 ng/mL. Results. The 18 patients included 14 simultaneous pancreas-kidney and 4 pancreas-after-kidney transplant recipients. Two patients were African-American, three patients had a pretransplant panel reactive antibody greater than 20%, and the human leukocyte antigen (HLA) mismatch was 4.5±1 (mean±standard deviation). With a mean follow-up of 13.6±4.7 months, patient, kidney, and pancreas graft survivals are 100%, 100%, and 94%, respectively. A single pancreas graft was lost to thrombosis. There were no acute rejection episodes and no opportunistic infections. Mean hospital stay was 9±3 days. At 3 months posttransplantation, the mean value of serum creatinine was 1.2±0.3 mg/dL, fasting glucose was 88±15 mg/dL, and sirolimus dose at month 3 was 6.3±3 mg per day and at month 12 2.7±1 mg per day. The average total daily cyclosporine A dose at month 3 was 208±62 mg per day and 133±13 mg per day at 1 year. Conclusions. This immunosuppressive regimen provided excellent prophylaxis against acute rejection with no opportunistic infections. We believe that careful monitoring of sirolimus and cyclosporine levels was critical to success of this protocol.

Combined lung and liver transplantation

Patients with end‐stage lung disease complicated by cirrhosis are not expected to survive lung transplantation alone. Such patients are potential candidates for combined lung‐liver transplantation (CLLT), however few reports document the indications and outcomes after CLLT. This is a review of a large single‐center CLLT series. Eight consecutive CLLT performed during 2009‐2012 were retrospectively reviewed. One patient received a third simultaneous heart transplant. Mean age was 42.5 ± 11.5 years. Pulmonary indications included cystic fibrosis (CF) (n = 3), idiopathic pulmonary fibrosis (n = 2), α1‐antitrypsin deficiency (AATD) (n = 1) and pulmonary hypertension (n = 2). Liver indications were CF (n = 3), hepatitis C (n = 2), AATD (n = 1), cryptogenic (n = 1), and cardiac/congestive (n = 1). Urgency was reflected by median lung allocation score (LAS) of 41 (36.0‐89.0) and median predicted FEV1 of 25.7%. Median donor age was 25 (20‐58) years with median cold ischemia times of 147 minutes and 6.1 hours for lung and liver, respectively. Overall patient survival at 30 days, 90 days and 1 year was 87.5%, 75.0% and 71.4% respectively. One patient had evidence of acute lung rejection, and no patients had liver allograft rejection. Early postoperative mortalities (90 days) were caused by sepsis in 2 recipients who exhibited the highest LAS of 69.9 and 89.0. The remaining recipients had a median LAS of 39.5 and 100% survival at 1‐year. Median length of stay was 25 days (7‐181). Complications requiring operative intervention included bile duct ischemia (n = 1) and bile leak (n = 1), ischemia of the bronchial anastomosis (n = 1), and necrotizing pancreatitis with duodenal perforation (n = 1). This series reflects a large single‐center CLLT experience. Sepsis is the most common cause of death. The procedure should be considered for candidates with LAS < 50. Liver Transpl 20:46–53, 2014.

Comparing an early corticosteroid/late calcineurin-free immunosuppression protocol to a sirolimus-, cyclosporine A-, and prednisone-based regimen for pancreas-kidney transplantation.

Aim. A prednisone and calcineurin inhibitor (CNI)-free protocol was compared with a sirolimus, cyclosporine A (CsA), and prednisone-based immunosuppressive regimen for simultaneous pancreas-kidney transplantation (SPK). Methods. A nonrandomized, single-center, sequential study enrolled low-immune responder SPK transplant recipients. The prednisone/CNI-free (minimization) group of 22 patients received thymoglobulin followed by sirolimus and reduced-dose CsA. Prednisone was withdrawn on day 5, and recipients were converted from CsA to mycophenolic acid at 6 months posttransplantation. The sirolimus/CsA group of 20 consecutive recipients transplanted immediately before this series received thymoglobulin followed by sirolimus, reduced-dose CsA, and prednisone. Results. Donor and recipient demographic variables were equivalent between groups. The 24-month actual patient, kidney, and pancreas survivals for the minimization group were 100%, 100%, and 91% vs. 100%, 95%, and 95% for the sirolimus/CsA group (P=not significant [NS] for patient, kidney, and pancreas survivals). One acute rejection occurred in the minimization group and none in the sirolimus/CsA group. After withdrawal of CsA at 6 months, the minimization group showed an increase in mean estimated glomerular filtration rate, resulting in a significant improvement in renal function compared with the sirolimus/CsA group. At 24 months, the mean glomerular filtration rate of the minimization and sirolimus/CsA groups was 71.6±11.2 mL/min/1.73 m2 and 60.1±13.4 mL/min/1.73 m2, respectively (P<0.05). Mean fasting blood glucose levels were equivalent between groups at all time points studied. Conclusion. Low-immune responder SPK recipients receiving a prednisone/CNI-free protocol achieved similar 2-year graft survivals and improved renal function compared with those treated with a sirolimus, CsA, and prednisone regimen.

Pancreas transplantation utilizing thymoglobulin, sirolimus, and cyclosporine

Background. This study aims to determine the impact of thymoglobulin-sirolimus-cyclosporine immunosuppression on the alloimune response of pancreas-kidney transplant recipients. Methods. Thirty-six pancreas transplant recipients received an induction protocol of thymoglobulin, sirolimus, reduced-dose cyclosporine, and corticosteroids. Ten recipients were also enrolled in a study to measure immune responsiveness. Flow PRA determined HLA antibody, donor-specific flow cytometry crossmatching (FCXM), T-cell subset, and suppressor cell assays were performed during the first posttransplant year. Results. One-year patient, kidney, and pancreas graft survivals were 97%, 94%, and 92%, respectively. There was one death and three graft losses. There were no acute rejection episodes. Recipients in the immune-monitoring study (n=10) displayed >80% depression of CD3, CD4, and CD8 (+) cell counts up to 3 months posttransplant. At transplantation 9/10 patients displayed <10% class I and no class II HLA antibody. By 3 months, 7/10 monitored recipients showed a transient elevation in class I HLA antibodies, including 2 patients who expressed >80% Flow PRA. One patient was pretransplant FCXM positive, whereas by 3 months posttransplant 2/10 patients demonstrated a positive FCXM. There were no clinical consequences of the presence of HLA antibody or the positive FCXMs. By 6 months, 7/9 patients demonstrated immunoregulatory suppressor cells. Conclusions. The absence of acute rejection events was likely due to inhibition of donor-specific immunity by the immunosuppressive regimen. Seventy percent of patients demonstrated an early, nondonor-directed HLA antibody response that had no adverse effect on graft function and 78% of the monitored patients displayed immunoregulatory cells probably contributing to the successful outcomes.