Suitability of Estimated Glomerular Filtration Rate for Live Kidney Donor Selection

INTRODUCTION

The assessment of the glomerular filtration rate (GFR) in kidney donor candidates is required for determining donor candidate acceptability. This assessment can be done using an estimated GFR (eGFR) or a measured GFR (mGFR). The primary objective of the present study was to compare, in healthy adult kidney donor candidates, GFR measured by the clearance of iothalamate to GFR estimated using the Chronic Kidney Disease Epidemiology Collaboration equation and to determine if eGFR was a suitable stand-alone assessment. A secondary objective was to explore demographic factors that affect the relationship of the eGFR and the mGFR.

METHODS

A retrospective review of kidney donor candidates' records at the J. C. Walter, Jr., Transplant Center, Houston Methodist Hospital, from January 2013 to March 2016 was undertaken. GFR was measured by the plasma clearance of radioisotopic iothalamate and estimated using the Chronic Kidney Disease Epidemiology Collaboration equation.

RESULTS

The median mGFR was 108 mL/min/1.73 m². The eGFR underestimated the mGFR by 11.5%. The underestimation was greatest in subjects with an mGFR of ≥90 mL/min/1.73 m². The eGFR overestimated the mGFR in donor candidates of black race.

CONCLUSIONS

The Chronic Kidney Disease Epidemiology Collaboration eGFR can be used for screening potential kidney donors restricting the use of iothalamate (mGFR) to those donors with an eGFR below the transplant centers' acceptable GFR threshold for donation, thereby effecting cost savings and greater donor convenience. The eGFR in black donor candidates should be used with caution.

Development of a Web Site for Transplant Patient Education

The Internet is a global communication network used by more than 17.6 million adults as a major source of current health information. Both the number of health-related Web sites and the number of Web users are increasing exponentially as well as reports indicating a growth in the number of persons who access the Internet specifically to retrieve information about organ transplantation. However, few are using this medium for posttransplant educational or psychosocial purposes. Armed with this information, as well as a commitment from the transplant team, we chose to develop a Web-based educational program to facilitate posttransplant care for our transplant recipients. The purpose of this article is to describe the planning, development, and implementation of a Web-based education program for transplant recipients.

Combination Drug Products for HIV-A Word of Caution for the Transplant Clinician

Modern-day treatment regimens for human immunodeficiency virus (HIV) are not only highly effective, but are now more often available as convenient fixed-dose combination products. Furthermore, as medication adherence is of utmost importance in this setting, national guidelines endorse the use of such products. Transplant providers of HIV-infected patients will undoubtedly encounter these products, some of which contain medications known to drastically alter the metabolism of certain immunosuppressants. Herein, we describe an instance of drug interaction-induced calcineurin inhibitor (CNI) nephrotoxicity in a renal transplant recipient being started on a cobicistat-containing combination product for HIV. CNI toxicity, in turn, was resolved with the aid of phenytoin as an inducer of drug metabolism. This case underscores the importance of familiarity with newer combination products on the market and constant communication with HIV-positive transplant recipients and their providers.

Sustained zero-order delivery of GC-1 from a nanochannel membrane device alleviates metabolic syndrome

BACKGROUND/OBJECTIVES

Our objective was to assess the sustained, low-dose and constant administration of the thyroid receptor-β (TRβ)-selective agonist GC-1 (sobetirome) from a novel nanochannel membrane device (NMD) for drug delivery. As it known to speed up metabolism, accomplish weight loss, improve cholesterol levels and possess anti-diabetic effects, GC-1 was steadily administered by our NMD, consisting of an implantable nanochannel membrane, as an alternative to conventional daily administration, which is subject to compliance issues in clinical settings.

SUBJECTS/METHODS

Diet-induced obese C57BL/J6 male mice were fed a very high-fat diet (VHFD) and received NMD implants subcutaneously. Ten mice per group received capsules containing GC-1 or phosphate-buffered saline (control). Weight, lean and fat mass, as well as cholesterol, triglycerides, insulin and glucose, were monitored for 24 days. After treatment, plasma levels of thyroid-stimulating hormone (TSH) and thyroxine were compared. mRNA levels of a panel of thermogenic markers were examined using real-time PCR in white adipose tissue (WAT) and brown adipose tissue (BAT). Adipose tissue, liver and local inflammatory response to the implant were examined histologically. Pancreatic islet number and β-cell area were assessed.

RESULTS

GC-1 released from the NMD reversed VHFD-induced obesity and normalized serum cholesterol and glycemia. Significant reductions in body weight and fat mass were observed within 10 days, whereas reductions in serum cholesterol and glucose levels were seen within 7 days. The significant decrease in TSH was consistent with TRβ selectivity for GC-1. Levels of transcript for Ucp1 and thermogenic genes PGC1a, Cidea, Dio2 and Cox5a showed significant upregulation in WAT in NMD-GC-1-treated mice, but decreased in BAT. Although mice treated by NMD-GC-1 showed a similar number of pancreatic islets, they exhibited significant increase in β-cell area.

CONCLUSIONS

Our data demonstrate that the NMD implant achieves steady administration of GC-1, offering an effective and tightly controlled molecular delivery system for treatment of obesity and metabolic disease, thereby addressing compliance.

Osteocalcin Effect on Human β-Cells Mass and Function

The osteoblast-specific hormone osteocalcin (OC) was found to regulate glucose metabolism, fat mass, and β-cell proliferation in mice. Here, we investigate the effect of decarboxylated OC (D-OC) on human β-cell function and mass in culture and in vivo using a Nonobese diabetic-severe combined immunodeficiency mouse model. We found that D-OC at dose ranges from 1.0 to 15 ng/mL significantly augmented insulin content and enhanced human β-cell proliferation of cultured human islets. This was paralleled by increased expression of sulfonylurea receptor protein; a marker of β-cell differentiation and a component of the insulin-secretory apparatus. Moreover, in a Nonobese diabetic-severe combined immunodeficiency mouse model, systemic administration of D-OC at 4.5-ng/h significantly augmented production of human insulin and C-peptide from the grafted human islets. Finally, histological staining of the human islet grafts showed that the improvement in the β-cell function was attributable to an increase in β-cell mass as a result of β-cell proliferation indicated by MKI67 staining together with the increased β-cell number and decreased α-cell number data obtained using laser scanning cytometry. Our data for the first time show D-OC-enhanced β-cell function in human islets and support future exploitation of D-OC-mediated β-cell regulation for developing useful clinical treatments for patients with diabetes.

New-Onset Diabetes After Transplantation: Results From a Double-Blind Early Corticosteroid Withdrawal Trial

New-onset diabetes after transplantation (NODAT) is an important complication following kidney transplantation. Data from the 5-year early steroid withdrawal double-blind randomized trial were analyzed to determine if steroid avoidance reduced the NODAT risk. Incidence, timing and risk factors for NODAT were evaluated using eight definitions. By American Diabetes Association definition, 36.3% of patients on chronic corticosteroids (CCS) and 35.9% on early corticosteroid withdrawal (CSWD) were diagnosed with NODAT by 5 years. The definition combining fasting blood glucose ≥126 mg/dL on two occasions or treatment identified slightly more cases of NODAT: CCS (39.3%) and CSWD (39.4%). Through 5 years posttransplant, the proportion of NODAT patients requiring treatment were similar (CSWD 22.5% vs. CCS 21.5%); however, insulin therapy was lower with CSWD (3.7% vs. 11.6%; p = 0.049). By multivariate analysis, only age, but not corticosteroid use, was a significant risk factor for NODAT for more than one definition. Numerical, but not statistically significant trends toward lower NODAT rates with CSWD were observed through 5 years for insulin use, HbA1c ≥6.0% and ≥6.5% on two occasions. This prospective, randomized trial of CSWD indicates that CSWD has a limited impact in reducing NODAT when compared to low-dose prednisone (5 mg/day from month 6 to 5 years).

Observations on the use of cidofovir for BK virus infection in renal transplantation

BACKGROUND

In renal transplantation, BK virus infection can result in significant graft nephropathy and loss. While reduction in immunosuppression (IS) is considered standard therapy, adjunct agents may be warranted. Data are suggestive of a possible role of cidofovir for the management of BK. This study aims to describe the course of BK viremia (BKV) in a large cohort of renal transplant patients receiving adjunct cidofovir.

METHODS

We evaluated kidney and kidney-pancreas recipients who received cidofovir combined with reduced IS for management of high-level BKV or BK virus nephropathy (BKVN). We examined the rate and timing of BKV clearance, and performed a multivariate analysis to identify risk factors associated with long-term (>6 months) viremia.

RESULTS

In total, 75 patients received a median of 13 doses of cidofovir in conjunction with reduced IS; 32 patients (43%) had short-term BKV (≤6 months), and 43 (57%) had long-term BKV. Overall, 53 of 75 patients (71%) eventually cleared BKV at a median of 4.2 months (interquartile range 2.1-9.3 months). Independent factors associated with long-term BKV included older age (odds ratio [OR] 1.1, P = 0.02), delayed graft function (OR 31.4, P = 0.01), and higher peak BKV (OR 12.8, P = 0.02), while BKV reduction by at least 1 log(10) copies/mL at 1 month of treatment was associated with clearance within 6 months (OR 49.3, P < 0.01). Patients with earlier clearance maintained stable graft function and no graft losses, while long-term BKV was associated with a 15% decline in estimated glomerular filtration rate.

CONCLUSIONS

Adjunct cidofovir resulted in preservation of renal function when viral clearance occurred within 6 months of initiation. This retrospective review defines factors predicting response to cidofovir in conjunction with reduced IS for BKVN or high-level BKV. Still, considering cost, frequency of administration, and treatment duration, a randomized trial is necessary to define the exact utility of cidofovir in the setting of BK virus infection.

Quantifying the risk of incompatible kidney transplantation: a multicenter study

Incompatible live donor kidney transplantation (ILDKT) offers a survival advantage over dialysis to patients with anti-HLA donor-specific antibody (DSA). Program-specific reports (PSRs) fail to account for ILDKT, placing this practice at regulatory risk. We collected DSA data, categorized as positive Luminex, negative flow crossmatch (PLNF) (n = 185), positive flow, negative cytotoxic crossmatch (PFNC) (n = 536) or positive cytotoxic crossmatch (PCC) (n = 304), from 22 centers. We tested associations between DSA, graft loss and mortality after adjusting for PSR model factors, using 9669 compatible patients as a comparison. PLNF patients had similar graft loss; however, PFNC (adjusted hazard ratio [aHR] = 1.64, 95% confidence interval [CI]: 1.15-2.23, p = 0.007) and PCC (aHR = 5.01, 95% CI: 3.71-6.77, p < 0.001) were associated with increased graft loss in the first year. PLNF patients had similar mortality; however, PFNC (aHR = 2.04; 95% CI: 1.28-3.26; p = 0.003) and PCC (aHR = 4.59; 95% CI: 2.98-7.07; p < 0.001) were associated with increased mortality. We simulated Centers for Medicare & Medicaid Services flagging to examine ILDKT's effect on the risk of being flagged. Compared to equal-quality centers performing no ILDKT, centers performing 5%, 10% or 20% PFNC had a 1.19-, 1.33- and 1.73-fold higher odds of being flagged. Centers performing 5%, 10% or 20% PCC had a 2.22-, 4.09- and 10.72-fold higher odds. Failure to account for ILDKT's increased risk places centers providing this life-saving treatment in jeopardy of regulatory intervention.

Effect of corticosteroid withdrawal on tacrolimus and mycophenolate mofetil exposure in a randomized multicenter study

As corticosteroid-sparing protocols are increasingly utilized in kidney transplant recipients, it is crucial to understand potential drug interactions between tacrolimus (TAC) and the effect of corticosteroid withdrawal as well as to characterize dose adjustments of mycophenolate mofetil (MMF) in this setting. This prospective, multicenter, randomized, double-blind study included 397 patients who were randomized on posttransplant day 8 to receive either placebo (CSWD) or corticosteroid continuance (CCS). TAC trough levels at week two posttransplant were significantly greater in the CSWD group whereas TAC doses were comparable to the CCS group. This interaction was not observed in the African American subgroup. Higher serum creatinine and potassium levels were also observed in the CSWD group. MMF dose was significantly reduced in the CSWD group by the investigators because of decreased WBC counts, mostly outside of study protocol criteria, despite similar incidence of neutropenia and reported cytomegalovirus infection. Understanding TAC and MMF exposure in the context of corticosteroid-sparing protocols should allow for improved dosing of immunosuppressants and better management of posttransplant patients.

The PROMISE study: a phase 2b multicenter study of voclosporin (ISA247) versus tacrolimus in de novo kidney transplantation

Voclosporin (VCS, ISA247) is a novel calcineurin inhibitor being developed for organ transplantation. PROMISE was a 6-month, multicenter, randomized, open-label study of three ascending concentration-controlled groups of VCS (low, medium and high) compared to tacrolimus (TAC) in 334 low-risk renal transplant recipients. The primary endpoint was demonstration of noninferiority of biopsy proven acute rejection (BPAR) rates. Secondary objectives included renal function, new onset diabetes after transplantation (NODAT), hypertension, hyperlipidemia and pharmacokinetic-pharmacodynamic evaluation. The incidence of BPAR in the VCS groups (10.7%, 9.1% and 2.3%, respectively) was noninferior to TAC (5.8%). The incidence of NODAT for VCS was 1.6%, 5.7% and 17.7% versus 16.4% in TAC (low-dose VCS, p = 0.03). Nankivell estimated glomerular filtration rate was respectively: 71, 72, 68 and 69 mL/min, statistically lower in the high-dose group, p = 0.049. The incidence of hypertension and adverse events was not different between the VCS groups and TAC. VCS demonstrated an excellent correlation between trough and area under the curve (r(2) = 0.97) and no difference in mycophenolic acid exposure compared to TAC. This 6-month study shows VCS to be as efficacious as TAC in preventing acute rejection with similar renal function in the low- and medium-exposure groups, and potentially associated with a reduced incidence of NODAT.

Serial analysis of biomarkers of acute pancreas allograft rejection

Pancreas transplant recipients experience graft loss in spite of improvements in immunosuppressant therapies and diagnostic technologies. Therefore, a method to improve detection and management of acute rejection is needed. This longitudinal study investigated the usefulness of three biomarkers, granzyme B, perforin, and human leukocyte antigen-DR alpha (HLA-DR) measured by real-time PCR on peripheral blood mononuclear cells, for their ability to detect acute rejection and its resolution in 13 recipients of pancreas allograft. Data demonstrated that pre-transplant baseline expression of biomarkers decreased following the initiation of immunosuppression. Throughout follow-up (range 3-27 months), individuals without acute rejection episodes had little variation in their biomarker levels. Recipients with biopsy-proven rejection had a significant increase in the levels of biomarkers as early as five wk before clinical rejection diagnosis. Furthermore, all seven patients with biopsy-proven rejection demonstrated a decrease in the levels of granzyme B and perforin following the increased immunosuppression for the treatment of rejection. This is the first clinical serial measurement of biomarkers in recipients of pancreas transplants. The data demonstrate that upregulation of granzyme B, perforin, and HLA-DR in peripheral blood mononuclear cells are sensitive to changes in the immune environment and could possibly be used to identify those patients at higher risk of rejection.

De novo donor specific antibodies and patient outcomes in renal transplantation

Single antigen identification of HLA antibodies is used to detect donor specific antibodies (DSAs). However, the impact of DSA elements such as class, relative strength, duration, and longitudinal effect on graft function and survival, remains unclear. Routine DSAs (LabScreen, One Lambda, Inc., Canoga Park, CA) and metabolic studies were performed at 1, 3, 6, 9, and 12 months post-transplant, and every 6 months for renal transplant recipients from 7/2007-7/2010 (n = 389). Biopsies were evaluated by updated Banff 2005 guidelines after two consecutive positive DSAs. Based on these tests, 25% of recipients developed de novo DSA. Those with DSA had increased acute rejection episodes (AR), higher creatinine (Scr), and worse graft survival. Three subgroups of these patients were identified based on duration: persistent DSA (> 1), isolated DSA, or no DSA. Persistent DSA patients were more likely to be African American, and have higher mean fluorescence intensity (MFI) and AR rates. Persistent DSA patients, with or without AR, had elevated Scr. Recipients with DQ-only DSA had higher rates of antibody mediated rejection (AMR). From this, we conclude that routine posttransplant DSA monitoring identifies recipients at risk for graft damage or loss. Persistent de novo DSAs correlated with inferior graft outcomes and AMR. With or without AR, DSA persistence was associated with worse outcomes, possibly warranting intervention. De novo DQ-DSA may be a biomarker for chronic damage and/or AMR, while an isolated DSA determination appears clinically insignificant.

Prospects for future advancements in islet cell transplantation

Islet cell transplantation holds great promise for treating patients with type 1 diabetes mellitus (T1DM), and for preventing unstable metabolic state commonly refereed to as brittle diabetes in patients that undergo pancreatic resection given that it is a relatively noninvasive procedure and an attractive alternative to pancreas transplantation for restoring endogenous insulin secretion. The success of recent clinical trials for allogeneic islet transplantation as well as the increasing centers that perform auto-transplantation is showing that the beta cell replacement therapy for the treatment of patients with diabetes or total pancreatectomy has been firmly established. It needs only to be improved and made more widely available to the millions of desperate patients who search for alternatives to a life of insulin injections, hypoglycemia and the risks of end-organ damage. Steady progress has been achieved in recent years in different areas in the pancreatic islet transplantation process including islet cell processing, preservation, and immune therapies that justify optimism. To implement this therapeutic approach to larger cohorts of patients that would benefit from the restoration of beta cell function requires multiple interventions and the standardization of the different stages of islet transplant process. This article will review the possible areas of intervention and the ongoing research toward this important goal.

Changes in Abdominal Wounds Following Treatment With Sirolimus and Steroids in a Rat Model

Wound healing complications have been observed in patients receiving sirolimus (SLR). This study examined the degree and duration of delayed healing in various protocols using SLR. Sprague-Dawley rats underwent a standard midline abdominal incision and wound closure. Groups of 6 rats each were randomized to receive different doses of SLR (2 and 5 mg/kg) with or without loading dose (10 mg/kg x3 days), and with or without steroids (20 mg/kg x3 days followed by 5 mg/kg for 2 weeks). Rats were humanely killed on postoperative days 5, 10, or 15. Wound breaking force was measured using the EHMI BIAX-II instrument and tensile strength was calculated. Wounds in control animals had gradual increase in tensile strength during the 15-day observation. In contrast, high and loading doses of SLR caused reduction in wound strength until day 10, but the wounds' tensile strength became equivalent to control by day 15. The addition of steroids prolonged wound recovery with low doses of SLR until day 15 and had very profound effects on healing in high-dose SLR-treated animals (>50% reduction) that continued beyond the 2 weeks of observation. Low doses of SLR in non-steroid-treated animals had a short-term (5-day) impact on wound healing; high dose and loading doses delayed healing for 10 to 15 days. The addition of steroids had a synergistic effect on delayed wound healing, particularly in animals receiving high-dose SLR, which demonstrated prolonged wound weakness. These results may provide practical guidelines for postoperative introduction of SLR in the context of various clinical protocols.

Examination of Gene Expression Profile of Functional Human Pancreatic Islets After 2-Week Culture

Islet transplant faces significant challenges, mainly because of the high incidence of primary nonfunction of transplanted islets. Protocol modifications to improve the rate of islet function have included changes in pancreatic preservation and the introduction of short-term culture. Islet culture for 48 to 72 hours has become a standard part of most successful protocols for clinical islet transplantation. We have previously reported gene expression profiles associated with human pancreatic islet function. The aim of this study was to determine the change in gene expression profiles of functional islets after 2 weeks of culture in Memphis-serum free media. Human islets from four isolations were maintained in culture for 14 days in Memphis-serum free media. RNA was extracted from 10000 IEQ for analysis of the gene expression profiles using high-density Affymetrix U133A GeneChips and Genespring software. Islet function was assessed by measurements of human C-peptide at days 7 and 14 posttransplant into NOD-SCID mice. Human C-peptide levels were determined by radioimmunoassay. Our preliminary data showed that genes related to functionality, such as those directed toward insulin processing and secretion, did not vary over 14 days of culture, while genes related to exocrine pancreas and organ architecture and immune-associated genes decreased over time. The ability to maintain islets in culture is an important step toward the development of islet tissue repositories, as well as toward screening human islet preparations for additional pathogens.

Serial Peripheral Blood Cytotoxic Lymphocyte Gene Expression Measurements for Prediction of Pancreas Transplant Rejection

Acute rejection after pancreas transplantation remains a significant problem and contributes to immunological graft loss. No clinical markers of pancreas rejection have been universally accepted. The purpose of this study was to investigate the use of genetic markers; granzyme B, perforin, and HLA-DRA in the peripheral blood of pancreas transplant recipients. These genes have been identified in renal and islet cell transplant recipients as noninvasive tools to predict acute rejection. Blood samples were collected weekly for up to 1 year posttransplant. Surveillance biopsies of the pancreas were scheduled at weeks 2, 4, 8, and 12 as part of the typical posttransplant protocol for patients with pancreas alone or pancreas after kidney transplantation. Exclusion criteria included a diagnosis of biopsy-proven chronic rejection alone, pancreatitis, or kidney rejection within 2 months after pancreas biopsy. Gene expression levels of granzyme B, perforin, and HLA-DRA were compared in patients with (n = 7) and without biopsy proven acute rejection (n = 7). Recipients with acute rejection showed increased expression of granzyme B, HLA-DRA, as well as perforin genes compared to patients without biopsy-proven rejection. In addition, we observed that elevation of these genes occurred as early as 4 weeks before the traditional biopsy diagnosis, while the recipients with no rejection showed no change in gene expression. Our data indicated that serial measurements of peripheral blood granzyme B, perforin, and HLA-DRA gene expression can be a useful tool to predict pancreas rejection in its earliest stage.

Assessment of human islet viability using various mouse models

To date no in vitro viability test is known to accurately predict in vivo human islet function, making transplantation into various nonimmune animal models mandatory. The diabetic mouse model has been proposed as a standard method for human islet viability assessment. However, the use of streptozotocin for diabetes induction is associated with inconsistency with respect to induction protocols and the significant mortality rate. The purpose of this study was to compare a nondiabetic NOD-scid mouse model to its diabetic counterpart in terms of predicting islet viability. Diabetes was induced in NOD-scid mice using intraperitoneal injection of streptozotocin at concentrations ranging from 100 to 200 mg/kg. Blood glucose levels were monitored for 7 to 10 days, and mice that had levels of >300 mg/dL were used in the experiment. For nondiabetic mice, blood glucose and baseline human C-peptide levels were checked after an overnight fast. Transplantation of 2000 human islet equivalent was done in both models using the same technique. Islet function was determined in the diabetic mice by return to normoglycemia for 2 consecutive days and measurement of fasting human C-peptide on days 7 and 14 posttransplant. Viability was tested in nondiabetic mice after intraperitoneal injection of glucose (2 g/kg) and the measurement of human C-peptide levels using radioimmunoassay. Titration of the streptozotocin dose from 200 to 100 mg/kg showed a significant reduction in mice mortality (40% to 10%) and an increase of diabetes induction (55% to 81%). The 23 human islet isolations tested in both models showed complete consistency of the viability results.

OP-142 Gene Expression Profile of Nonfunctional Human Pancreatic Islets: Predictors of Transplant Failure?

Islet culture has become a standard part of most successful protocols for clinical islet transplantation. To date, however, islets are transplanted based on crude measures of viability, purity and in vitro insulin production without adequate prior assessment of the potential for in vivo function. The purpose of this study was to define the gene expression profiles of human islets associated with in vivo function using a nonimmune NOD-scid mouse model. Human islets from eight isolations were maintained in culture for 7 to 14 days in Memphis serum-free media until transplanted. The RNA was extracted from 10,000 IEQ using RNASTAT-60. The gene expression profiles were analyzed using high-density Affymetrix U133A GeneChips and Genespring software. An aliquot of 2000 IEQ from each islet preparation was also transplanted into NOD-scid animals (n = 5) for in vivo function assessments. Islet function was assessed by measurements of human C-peptide at days 7 and 14 posttransplant. Human C-peptide levels were determined by radioimmunoassay. Gene analysis of nonfunction islets (4 of 8 islet preparations) showed high relative levels of expression of proinflammatory genes and low relative levels of genes directed toward insulin processing and secretion as well as islet integrity. Overexpression of hypoxia and proinflammatory genes may result in reduced insulin secretion and lead to islet destruction posttransplantation. Identifying and validating those genes could allow the development of a potency assay for human transplantation that would be very useful for screening human islet preparations before clinical transplant.

Examination of the Molecular Signature Associated With Islet Dysfunction

The aim of this study was to identify the molecular signatures that are predictive of nonfunctional islet preparations. We examined functional outcomes of six islet preparations accepted for research purposes from human donors. Islet were maintained on culture in M-SFM media for 7 to 14 days then transplanted into NOD-SCID mice. At the time of transplant, RNA was extracted from a second aliquot of cultured islets for expression analysis. We also performed gene expression analysis using high-density Affymetrix U133A GeneChips on these preparations. Among 1833 genes selected, hierarchical clustering was performed using the GeneSpring software package (Silicon Genetics, Inc.), where 754 genes (higher in nonfunctional) and 177 genes (lower in nonfunctional) were differentially expressed with tight pattern of expression. Islets with low functionality showed high relative levels of expression of hypoxia-induced genes and increased frequency of expression of proinflammatory and proangiogenic genes, such as vascular endothelial growth factor. Conversely, nonfunctional islets had low levels of insulin-processing message. The general profile of these low-functionality islets shows attempted recovery from hypoxic assault and little effort directed toward insulin production and secretion. Further identification of the molecular signature of nonfunctional islets could allow the development of a potency assay for human transplantation.

Are Autoimmune Diseases or Glomerulonephritis Affecting the Development of Panel-Reactive Antibodies in Candidates for Renal Transplantation?

Panel-reactive antibodies (PRA) are a major obstacle to kidney transplantation (KTx). It is not completely clear why only some patients develop PRA, whereas others do not. We hypothesized that other factors, such as autoimmune diseases involving the kidney, might be a trigger for PRA development. We reviewed the original diseases that led to renal failure and their possible role in PRA development. Charts of 270 patients on the active waiting list for KTx were reviewed for complete demographics, presence of PRA, peak PRA level, first KTx or retransplantation, original disease, blood transfusions, pregnancy and rejection. Patients were divided into group 1 (PRA >10%) and group 2 (PRA <10%). There was a significantly higher proportion of patients in group 1 with autoimmune diseases than in group 2. The same proportion was found significant for all of the patients as well as for the patients listed for the first KTx (new patients). Previous KTx has significant impact on both class I and II peak PRA levels when compared with new patients who are already sensitized. A subanalysis of retransplantation showed patients with autoimmune disease (54%) have more graft loss due to rejection compared with nonautoimmune disease (43%). There is an association between high PRA level and autoimmune diseases causing renal failure regardless of the previous KTx status. Besides the risk of recurrence, autoimmune disease seems to affect the risk of graft loss due to rejection.

Adenovirus-based vascular endothelial growth factor gene delivery to human pancreatic islets

Islet transplantation is limited by islet graft failure due to poor revascularization, host immune rejection and nonspecific inflammatory response. Delivery of human vascular endothelial growth factor (hVEGF) gene to the islets is likely to promote islet revascularization and survival. We used a bicistronic adenoviral vector encoding hVEGF and CpG-free allele of green fluorescent protein (Adv-GFP-hVEGF) and introduced into human pancreatic islets by transfection. We found that transfection efficiency and apoptosis were dependent on the multiplicity of infection (MOI). Compared to Adv-GFP transfected and nontransfected islets, the levels of hVEGF secreted from Adv-GFP-hVEGF transfected islets were higher and exhibit a linear relationship between hVEGF expression and MOI (10-5000). Persistent, but low level expression of hVEGF from nontransfected islets was also observed. This may be due to expression of the endogenous hVEGF gene under hypoxic conditions. The levels of DNA fragmentation determined by ELISA of islet lysates were dependent on the MOI of Adv-GFP-hVEGF. On glucose challenge, insulin release from transfected islets was comparable to nontransfected islets. Immunohistochemical staining for hVEGF was very high in Adv-GFP-hVEGF transfected islets. Weak staining was also observed for hCD31 in both transfected and nontransfected islets. These findings suggest that Adv-GFP-hVEGF is a potential candidate for promoting islet revascularization.

Renal pathology and clinical presentations of polyomavirus nephropathy in simultaneous kidney pancreas transplant recipients compared with kidney transplant recipients

INTRODUCTION

The purpose of this study was to describe and compare the renal histopathology and clinical course of simultaneous kidney-pancreas transplant (SKP) recipients with kidney transplant (KT) recipients with polyomavirus nephropathy (PVN).

METHODS

Between 1997 and 2002, 20 patients (7 SKP, 13 KT) were diagnosed with PVN. Clinical characteristics and outcomes of PV-N were correlated with histopathologic examinations of renal allograft biopsy and compared between SKP and KT recipients.

RESULTS

There were no differences in demographics between SKP and KT recipients with PV-N. The mean time to PVN was 611 (172 to 1174) days posttransplant in SKP and 343 (83 to 720) days posttransplant in KT (P =.05). The serum creatinine at the time of diagnosis was similar between SKP and KT recipients. All patients were treated with reduction in immunosuppression. After a median follow-up of 2 years, the patient survival was 71% in SKP and 100% in KT. Four grafts (57%) were lost owing to PVN in SKP group and three grafts (23%) were lost owing to PVN in the KT group. More patients (43%) in SKP had a history of acute rejection prior to diagnosis of PVN compared to KT (8%) and biopsy-proven tacrolimus nephrotoxicity prior to PVN was more common in SKPT (86%) than in KT (8%) patients (P <.05). SKP patients with evidence of diffuse fibrosis and high total sum scores at time of presentation all subsequently lost their grafts.

CONCLUSIONS

SKP recipients with PVN had a worse clinical course than KT recipients.

Gastroparesis following kidney/pancreas transplant

This pilot study examined associations among patterns of gastric myoelectrical activity, symptoms of gastroparesis, years of diabetes, months of dialysis, and use of gastrointestinal medications in gastroparetic kidney-pancreas (KP) transplant recipients. Electrogastrography (EGG) and gastric symptom data were obtained from 42 transplant recipients before and after transplant (6, 12, and 24 months). Recipients were 38 +/- 7 yr of age, 88% Whites, and 60% male; 97% had hypertension. All had functioning grafts post-transplant (mean creatinine, 1.59 +/- 0.66 mg/dL, and serum glucose 91.97 +/- 24.92 mg/dL). Sixteen subjects had normal EGG (2.7-3.2 cycles per minute, cpm); two were tachygastric (>3.2 cpm) at all time points; one remained bradygastric (<2.7 cpm) throughout the study period. Following transplant, symptoms lessened and were associated with 6-month normalization of EGG (r = 0.41, p = 0.02). A small change in the percentage of patients with normal EGG was observed from baseline to 24 months (67% vs. 69% respectively); however, there was a shift from bradygastria (29% to 15% respectively) to tachygastria (5% to 15% respectively). Prescribed prokinetic and antisecretory medications use increased over the study period from 13 (31%) subjects at baseline to 32 (86%) at 6 months; 21 (78%) at 12 months; and 12 (92%) at 24 months. Although symptoms diminish following transplant, gastroparesis remains a significant problem for transplant patients. Normalization of EGG and shifts from bradygastria to tachygastria occur post-transplant. Our results suggest that serial EGGs and frequent assessment of symptoms can be used to follow gastroparesis in KP recipients.

Human islet graft function in NOD-SCID mice predicts clinical response in islet transplant recipients

The purpose of this study was to evaluate the utility of nondiabetic immune-deficient NOD-SCID mouse model in assessing the functional capacity of isolated human islets. We transplanted 2000 islet equivalents obtained from six preparations used for human islet transplantation in three patients under the kidney capsule of groups of 10 mice. Human (Hu) C-peptide and insulin levels were determined following intraperitoneal (i.p.) glucose challenge at days 0, 7, 14, 21, 30, 60, 90, and 120. The Hu C-peptide level >1.5 ng/mL was the threshold for islet function in this model. The first patient did not achieve insulin independence and had minimal (0.5 ng/mL) fasting C-peptide levels that mirrored the low C-peptide levels observed in the mice. After the first infusion, the insulin requirements were reduced by 50% in the second patient. She became insulin free 10 days after her second infusion with a C-peptide level of 3.0 ng/mL, which corresponded to the peak C-peptide level (3.9 ng/mL) observed in the mice. By 150 days' posttransplant, the decline in C-peptide level paralleled the decline observed in mice. Within 2 weeks after the first transplant, insulin dose was reduced by 75% in the third patient, which corresponded to the robust C-peptide production in mice (7.3 ng/mL). Both patient and mice had a delay in islet function following the second infusion. She remained with a C-peptide level of 1.8 ng/mL and insulin free until suffering a rejection episode 3 months later. We observed that human islet graft function in NOD-SCID mice correlated with clinical response in islet transplant recipients.

Retrospective evaluation of the risk of hepatitis B virus reactivation after transplantation

Numerous case reports describe patients with previously documented immunity developing active hepatitis B virus (HBV) infection after transplantation. However, the risk of reactivation of HBV under long-term immunosuppression in hepatitis B core antibody (HBcAb)-positive, hepatitis B surface antigen (HBsAg)-negative transplant recipients has not been clearly described. Herein, we present a long-term follow-up for 49 HBcAb-positive, HBsAg-negative recipients (27 liver, 18 kidney, 4 pancreas) transplanted between June 1996 and April 2001. Among these, 37 recipients (76%) were HBsAb positive at transplantation. Immunosuppression consisted of various antibody induction regimens in 20 (41%) of the recipients with either tacrolimus (33 [67%])- or cyclosporine (16 [33%])-based maintenance immunosuppression. The incidence and duration of HBV prophylaxis was not significant. No patient received hepatitis B immunoglobulin (HBIG) before or after transplantation. Additionally, only two patients received lamivudine, which was started post transplant without clinical indication. The mean length of follow-up was 3.1+/-1.4 years. At the last follow-up, overall patient and graft survival were 98% and 96%, respectively. Patient survival was 96% in liver, 100% in kidney, and 100% in pancreas transplant recipients. The graft survival for each organ type was 93% in liver, 100% in kidney, and 75% in pancreas transplant recipients at the end of follow-up. There was no incidence of HBV reactivation defined as recurrence of HBsAg and/or HBV DNA positivity. These data suggest that the risk of reactivation of HBV in HBcAb-positive, HBsAg-negative transplant recipients under immunosuppression is negligible, regardless of immunosuppressive regimen, lamivudine prophylaxis, or HBsAb status. These patients should have access to transplantation as they enjoy excellent patient and graft survival rates.

Observations on the use of sirolimus and tacrolimus in high-risk renal transplant recipients

Sirolimus is the first of a group of mammalian target of rapamycin inhibitors to be introduced for clinical use in the United States. At the University of Tennessee in Memphis, we have evolved strategies for the use of sirolimus in kidney transplant recipients; which utilize the drug as a primary immunosuppressant and exploit its potential for preserving renal function. Conversions from the calcineurins to sirolimusbased immunosuppression established the efficacy of calcineurin-free immunosuppressants in selected high-risk patients. The conversion experience stimulated the design of protocols for primary use of sirolimus. Posttransplant use of sirolimus was associated with low incidence of rejection whether sirolimus was used with low-dose Prograf or in calcineurin-free protocols. Primary use with full-dose Prograf was associated with a high incidence of calcineurin-related nephrotoxicity and was abandoned in our program. Hematologic and lipid side effects were manageable, as was an observed increase in wound-healing problems and lymphocele formation. Continuous modifications of the sirolimus protocols to increase our benefit-to-risk ratio are ongoing and indicate a continued role for the drug in posttransplant immune suppression.

Conversion to sirolimus in solid organ transplantation: a single-center experience

BACKGROUND

Calcineurin inhibitors are associated with adverse events, including nephrotoxicity and diabetes that might reduce the benefits of long-term graft survival. We report our experience in converting kidney (K), kidney-pancreas (KP), pancreas (P), and (L) recipients from a calcineurin inhibitor/mycophenolate mofetil (MMF)/prednisone dose-induced nephrotoxicity (K = 9, KP = 5, P = 1, L = 5), hemolytic uremic syndrome (HUS) (K = 7, KP = 5), chronic allograft nephropathy (K = 12, L = 1), and glucose intolerance (K = 9, KP = 6, P = 2, L = 2).

METHODS

The conversion protocol consisted of an abrupt discontinuation of the calcineurin inhibitor with sirolimus (8-12 mg, PO loading dose) initiated 24-72 hours after stopping the calcineurin inhibitor. Sirolimus was titrated to target trough levels of 12-16 ng/mL. Daclizumab 2 mg/kg IV was given to all KP and P recipients on days 0 and 14 postconversion.

RESULTS

Resolution of HUS occurred in 12 of 12 patients (100%) with a drop in serum creatinine from 3.3 +/- 1.5 to 1.8 +/- 0.9 mg/dL (P =.04). Sirolimus conversion due to nephrotoxicity, HUS, and chronic allograft nephropathy improved serum creatinine from 2.9 +/- 1.4 to 2.2 +/- 0.9 mg/dL (P =.01). Eleven of 19 patients (58%) resolved glucose intolerance. Two patients suffered rejection due to noncompliance. Increases in cholesterol (208 +/- 70 to 243 +/- 77 mg/dL, P <.05) and triglycerides (232 +/- 145 to 265 +/- 148 mg/dL, P = NS), and minimal reduction in platelet values (243 +/- 85 to 237 +/- 85, P = NS) occurred.

CONCLUSIONS

These data suggest that a calcineurin inhibitor-free immunosuppressive regimen with sirolimus, mycophenolate mofetil, and steroids preserves graft function in patients with clinical indications warranting calcineurin inhibitor discontinuation.

Polyomavirus in kidney and kidney-pancreas transplant recipients

PURPOSE

To report the incidence and clinical characteristics of polyomavirus (PV) nephritis in kidney (KTX) and kidney-pancreas transplant (KPTX) recipients.

METHODS

Single center retrospective analysis of all cases of PV nephritis in KTX and KPTX patients transplanted between 1994 and 1999.

RESULTS

Thirteen (5 KTX and 8 KPTX) patients (2.1%) had PV nephritis diagnosed on multiple biopsies (n = 22) among 504 KTX and 106 KPTX recipients. The incidence of PV nephritis was higher in cadaver donor transplants (2.6% cadaver vs. 0.7% living donors), after KPTX (1% KTX vs. 7.5% KPTX), in males (3.3% male vs. 0.7% female), and in diabetic patients (4.4% diabetic vs. 0.8% nondiabetic). The mean time to diagnosis of PV nephritis was 18 (range 6-48) months after KTX and 17 (range 9-31) months after KPTX. Three KTX patients and 5 KPTX patients had calcineurin inhibitor toxicity on biopsy prior to developing PV nephritis. Reduction in immunosuppression occurred in 100% of KTX and 63% of KPTX patients. Three patients (23%) developed rejection within 3 months of diagnosis of PV, 1 after a reduction in immunosuppression. Despite multiple antiviral treatment regimens, renal allograft failure requiring dialysis occurred in 60% of KTX and 50% of KPTX patients. All KPTX patients remain insulin independent and 2 were successfully retransplanted with living donor kidneys. 2 patients (15%) died but there was no mortality directly related to the virus.

CONCLUSIONS

Polyomavirus nephritis may be increasing in incidence and appears to be unresponsive to either conventional antiviral agents or a reduction in immunosuppression. Most of our cases occurred in male diabetic patients undergoing cadaveric donor transplantation and were preceded by biopsy-proven nephrotoxicity. Further studies are needed to better define the pathogenesis of PV and effective antiviral treatment.

Evolving experience of hepatitis B virus prophylaxis in liver transplantation

Passive immunoprophylaxis with hepatitis B immunoglobulin (HBIG) is important to prevent recurrence of hepatitis B virus (HBV) after orthotopic liver transplantation (OLT) for chronic HBV cirrhosis. With availability of lamivudine (3TC), the use of combination prophylaxis with long-term HBIG/3TC has been shown to prevent short-term HBV recurrence. This report compares HBV recurrence rates between groups receiving no/short-term HBIG, long-term HBIG alone, or HBIG/3TC prophylaxis, and describes HBIG requirements during the first 6 and 12 months in the latter two groups. This study involved patients undergoing OLT at the University of Tennessee-Memphis between May 1990 and July 2001. During this period, 388 liver transplants were performed at our center. All hepatitis B surface antigen (HBsAg)-positive recipients (n = 27) were included in this retrospective analysis. The groups were similar with regard to pre-transplant demographic characteristics such as age, gender, weight, and pre-transplant diagnosis. Owing to the retrospective study design, median follow-up was longer for the no-prophylaxis (5.6 years) and the HBIG-alone (6.0 years) groups compared to the HBIG/3TC group (4.2 years). Patient survival was 50% in the no-prophylaxis and 71% in the HBIG-alone groups compared to 100% in the HBIG/3TC group (P = 0.09). When censored for death with a functioning graft, graft survival was 50% in the no-prophylaxis and 86% in the HBIG-alone group compared to 100% in the HBIG/3TC group (P = 0.07). The overall incidence of HBV recurrence in the no-prophylaxis era was 100% and 21% in the HBIG-alone era compared to 0% in the HBIG/3TC era (P < 0.001), despite similar mean and median HBIG trough titers in the HBIG-alone and HBIG/3TC groups. The incidence of HBV recurrence in HBV DNA-positive recipients was 100% in the no-prophylaxis era, 30% in the HBIG-alone era, and 0% in the HBIG/3TC era (P < 0.001). Recipients in the HBIG-alone group had a nearly two-fold increase in HBIG requirement at 6 and 12 months in order to maintain similar HBIG trough titers post-transplant compared to recipients in the HBIG/3TC group despite similar pre-transplant HBV serology. This increased HBIG requirement in the HBIG-alone group resulted in a marked increase in the mean overall cost of HBV prophylaxis in this group ($47,367 US dollars at 6 months; $84,280 US dollars at 12 months) compared to the HBIG/3TC group ($25,931 US dollars at 6 months; $49,599 US dollars at 12 months). These data demonstrate an improvement in patient and graft survival rates in the group receiving combination HBIG/3TC prophylaxis compared to the HBIG-alone and no-prophylaxis groups. There was a significant reduction in HBV recurrence in the group receiving combination HBIG/3TC when compared to the groups receiving HBIG alone or no prophylaxis. Furthermore, we demonstrated that the addition of 3TC to the long-term HBIG regimen led to elimination of the disparity previously described in HBV recurrence rates between HBV DNA-positive and HBV DNA-negative recipients. Importantly, our data demonstrates a complete lack of HBV recurrence in the HBIG/3TC group at a median follow-up of 4.2 years. Additionally, the data show that the addition of 3TC to the post-operative prophylaxis regimen resulted in a reduction in the requirement of HBIG at 6 and 12 months, which markedly reduced the overall cost of post-transplant HBV prophylaxis.

Lifestyle behaviors affect cardiovascular risk status in men 1 year after kidney transplantation

Persons with end-stage renal disease have an accelerated risk for cardiovascular (CV) morbidity and mortality. Unfortunately, their accelerated CV risk persists even after kidney transplantation associated with pretransplant and post-transplant vascular disease. number of rejections treated with high-dose steroids, prolonged use of immunosuppressive therapy post-transplant, effects of comorbid chronic conditions and male gender. Unhealthy, modifiable lifestyle practices often augment their CV risk. The purpose of this study was to examine health-related lifestyle behaviors and estimate CV risks of men 1 year following kidney transplantation. Using the Healthier People Network Health Risk Appraisal (HPN-HRA), we examined CV risk characteristics of 34 men (M age=47.3 years) enrolled in an urban, mid-southern transplant center. Participants were assessed via self-administered paper-and-pencil questionnaires and medical record review provided biological data for analyses. HPN-HRA software was used to analyze biological and behavioral characteristics to compute CV risk estimates. Data were analyzed using descriptive, inferential and correlational analyses. The majority of participants reported smoke cessation (n= 19) or never having smoked (n = 8), and consumption of one or less alcoholic drinks per week (n=28). On the other hand, increased risk for heart attack and stroke were associated with advancing age (P<0.0001), white race (P<0.05) and higher systolic blood pressure (P<0.01). While risk for heart attack was associated with current cigarette smoking (P<0.01), risk for stroke was not. Conversely, risk for stroke was associated with higher BMI (P<0.05), risk for heart attack was not. Thus, the study provides evidence that male kidney transplant survivors exhibit a significant number of non-modifiable and modifiable characteristics that contribute to their posttransplant CV risk.

Rhodococcus equi pulmonary infection in a pancreas-alone transplant recipient: consequence of intense immunosuppression

We report the case of a pancreas-alone transplant recipient who developed Rhodococcus equi pneumonia after receiving multiple courses of antilymphocyte therapy for the treatment of recurrent acute pancreas allograft rejection. We also review and discuss the diagnosis, clinical course, and treatment of 18 cases of R. equi infection reported in solid organ transplant recipients. The lung is the most common primary site of infection, but R. equi infection is difficult to diagnose because of the pleomorphic, gram-positive, and partially acid-fast nature of the organism. Treatment usually involves a combination of antibiotics including rifampin, macrolides, vancomycin, and ciprofloxacin. The optimal duration of therapy is unknown, but relapse is common if the duration of treatment is less than 14 days. The duration of therapy should be guided by clinical recovery, culture results, and radiographic findings. Monitoring levels of immunosuppressive agents-such as tacrolimus and cyclosporine-is needed in order to avoid clinically significant drug interactions with rifampin or the macrolides when these agents are used in order to treat R. equi infection in the transplant population.

Initial clinical experience with interleukin-2 receptor antagonist induction in combination with tacrolimus, mycophenolate mofetil and steroids in simultaneous kidney-pancreas transplantation

Since 1996, our standard immunosuppressive protocol for simultaneous kidney-pancreas transplantation (SKPT) has been tacrolimus (TAC), mycophenolate mofetil (MMF) and steroids without antibody induction. When basiliximab and daclizumab, monoclonal antibodies directed against the interleukin-2 receptor (IL-2R), became available, we selectively added these agents to our standard protocol. The purpose of this prospective, open-label study was to evaluate the safety and efficacy of IL-2 receptor antagonists in SKPT. From April 1998 to August 1999, 35 SKPTS were performed. One patient with delayed graft function received Thymoglobulin and was excluded; 17 received no induction, and 17 received IL-2R antagonists (9 basiliximab, 8 daclizumab) as induction. Demographic- and transplant characteristics were similar between the two groups. At 6 months, patient survival was 88 % (15/17) in the induction arm compared to 100 % (17/17) in the no-induction arm, P = NS. The 2 causes of death were sepsis and hemolytic uremic syndrome, and both patients died with functioning grafts. Death-censored pancreas and kidney graft survival rates in the induction and the no-induction groups were 88 % vs. 100 % respectively, in both groups. The incidence of acute rejection (kidney or pancreas) at 6 months did not differ between the two groups (35 % in both groups). Biopsy proven pancreas and kidney acute rejections were 35 % vs. 24 % and 12 % vs. 12 % in the induction- and no-induction groups, respectively. The incidences of major infection and readmission did not differ between groups. TAC trough levels and mean daily doses of TAC, MMF and steroids did not differ between the two groups at 1, 3, and 6 months. The incidence of event-free survival (no death, rejection, or graft loss) at 6 months was 59 % (10/17) in the induction and 65 % (11/17) in the no-induction group. Basiliximab and daclizumab appear to be safe in SKPT. However, the preliminary results of this study do not demonstrate a significant benefit in either reducing the incidence of acute rejection or improving outcomes at 6 months. Larger studies with longer follow-up are needed to confirm these findings.

Improved in vivo pancreatic islet function after prolonged in vitro islet culture

BACKGROUND

Difficulties with recovering and preserving pancreatic islets have hampered progress in islet transplantation. In previous in vitro studies, our laboratory successfully demonstrated that using serum-free medium for prolonged pancreatic islet culture allows postculture recovery ratios greater than those obtained with standard media with sustained in vitro islet function. The goal of this study was to determine whether culturing of islets in a modified serum-free medium (M-SFM) would sustain function in vivo.

METHODS

Islets were isolated from pancreata procured from 12 cadaveric organ donors and cultured in the M-SFM for up to 2 months, cryopreserved at -70 degrees C within 1-3 days of isolation for 2 months, or placed in short-term culture (3-5 days) before their transplantation under the kidney capsule of nonobese diabetic-severe combined immunodeficient mice (n=4-7 per group/time point). In vivo islet function was assessed by measuring the production of human insulin and C-peptide over a period of 3-15 months.

RESULTS

After extended culture of islets in M-SFM for 1 or 2 months, transplanted islets maintained their viability, and in some instances in vivo function improved when compared with short-term cultured islets transplanted from the same preparation (P<0.01). Improvement was particularly evident for islets cultured for 1 month. Furthermore, when compared with cryopreserved preparations, early function (postoperative day 7) of islets from 1-month culture preparations was statistically better (P<0.05). Prolonged culture in M-SFM had no significant impact on long-term function, inasmuch as cultured islets functioned for more than 120 days.

CONCLUSION

These data demonstrate that prolonged islet culture in M-SFM sustained viability and function, and in some instances had a positive effect on in vivo islet function, particularly in the 1-month cultures. No negative effect on long-term in vivo function was demonstrated in this study. Confirmation in clinical models utilizing extended (1-2 months) islet culture in M-SFM could significantly enhance islet transplantation by allowing the identification of best-matched recipients, pretransplantation recipient conditioning, and possible pretransplantation islet modifications to promote engraftment and prolonged graft function.

Initial clinical experience with interleukin-2 receptor antagonist induction in combination with tacrolimus, mycophenolate mofetil and steroids in simultaneous kidney-pancreas transplantation

Since 1996, our standard immunosuppressive protocol for simultaneous kidney-pancreas transplantation (SKPT) has been tacrolimus (TAC), mycophenolate mofetil (MMF) and steroids without antibody induction. When basiliximab and daclizumab, monoclonal antibodies directed against the interleukin-2 receptor (IL-2R), became available, we selectively added these agents to our standard protocol. The purpose of this prospective, open-label study was to evaluate the safety and efficacy of IL-2 receptor antagonists in SKPT. From April 1998 to August 1999, 35 SKPTS were performed. One patient with delayed graft function received Thymoglobulin and was excluded; 17 received no induction, and 17 received IL-2R antagonists (9 basiliximab, 8 daclizumab) as induction. Demographic- and transplant characteristics were similar between the two groups. At 6 months, patient survival was 88 % (15/17) in the induction arm compared to 100 % (17/17) in the no-induction arm, P = NS. The 2 causes of death were sepsis and hemolytic uremic syndrome, and both patients died with functioning grafts. Death-censored pancreas and kidney graft survival rates in the induction and the no-induction groups were 88 % vs. 100 % respectively, in both groups. The incidence of acute rejection (kidney or pancreas) at 6 months did not differ between the two groups (35 % in both groups). Biopsy proven pancreas and kidney acute rejections were 35 % vs. 24 % and 12 % vs. 12 % in the induction- and no-induction groups, respectively. The incidences of major infection and readmission did not differ between groups. TAC trough levels and mean daily doses of TAC, MMF and steroids did not differ between the two groups at 1, 3, and 6 months. The incidence of event-free survival (no death, rejection, or graft loss) at 6 months was 59 % (10/17) in the induction and 65 % (11/17) in the no-induction group. Basiliximab and daclizumab appear to be safe in SKPT. However, the preliminary results of this study do not demonstrate a significant benefit in either reducing the incidence of acute rejection or improving outcomes at 6 months. Larger studies with longer follow-up are needed to confirm these findings.

A 9-year experience with 126 pancreas transplants with portal enteric drainage

HYPOTHESIS

A novel technique of pancreas transplantation (PTX) with portal venous delivery of insulin and enteric exocrine drainage (portal enteric) was developed at our center to improve the PTX procedure.

DESIGN

Case series.

SETTING

Single-center experience at a university hospital.

PATIENTS AND INTERVENTION

From October 1990 through December 1999, we performed 126 PTXs with portal enteric drainage, including 90 simultaneous kidney PTXs (SKPT) and 36 solitary PTXs (18 sequential PTXs after kidney transplantation and 18 PTXs alone).

MAIN OUTCOME MEASURES

Patient and graft survival rates; medical and surgical morbidity. Three groups, representing 3 eras of immunosuppression, were compared. Thirty patients underwent SKPT with muromonab-CD3 induction and cyclosporine-based therapy in era 1 (October 1990 through June 1995); 42 SKPTs received tacrolimus and mycophenolate mofetil-based immunosuppression without antibody induction in era 2 (July 1995 through May 1998); and 18 SKPTs were performed in era 3 (June 1998 through December 1999) with either basiliximab or daclizumab induction.

RESULTS

One-year patient survival rates after SKPT were 77% in era 1, 93% in era 2, and 100% in era 3 (P =.03). The 1-year kidney graft survival rates were 77% in era 1, 93% in era 2, and 94% in era 3 (P =.08). The 1-year pancreas graft survival rates after SKPT were 60% in era 1, 83% in era 2, and 83% in era 3 (P =.06). The incidences of rejection (63% vs. 33% vs. 39%; P<.001) and thrombosis (20% vs. 7% vs. 6%; P<.001) were decreased in eras 2 and 3.

CONCLUSION

Simultaneous kidney PTXs with portal enteric drainage can be performed with improved outcomes.

Renal allograft outcomes in African American versus Caucasian transplant recipients in the tacrolimus era

METHODS

Between January 1995 and December 1999, 185 kidney transplants were performed with tacrolimus (TAC)-based immunosuppression including 120 African American (AA, 65%) and 65 Caucasian recipients (C, 35%). Mean follow-up was 34 months. The AA group was characterized by a higher incidence of renal disease due to hypertension (72% AA vs 37% C, P <.001), pretransplant dialysis (95% AA vs 82% C, P =.003), waiting time (1.9 years AA vs 1.1 years C, P =.02), cadaveric donation (88% AA vs 68% C, P =.01), HLA mismatching (mean 3.5 AA vs 2.4 C, P <.001), and delayed graft function (DGF; 50% AA vs 22% C, P =.001).

RESULTS

The 5-year actuarial patient and graft survival rates were 96% AA versus 83% C (P = NS) and 83% AA versus 75% C, (P = NS), respectively. The incidence of acute rejection (21% AA vs 12% C, P = NS) and mean time to acute rejection (12 months AA vs 11 months C) were similar. Although the incidence of chronic allograft nephropathy (CAN) was comparable (7% AA vs 5% C), the mean time to CAN was shorter in AA recipients (18 months AA vs 37 months C, P =.03).

CONCLUSIONS

These results suggest marked improvement in post-transplant outcomes in the TAC era in patients with multiple immunologic risk factors including AA ethnicity, cadaveric donor source, DGF, and HLA mismatching.

Portal-enteric pancreas transplantation at the University of Tennessee, Memphis

The UT Memphis group has made a number of important contributions to the field of PTX, including: 1) pioneering studies on the effects of PTX on autonomic neuropathy, 2) comprehensive reports dealing with quality of life after PTX, 3) seminal studies on the metabolic effects of PTX with portal venous delivery of insulin, 4) refining and perfecting a novel technique of PTX with portal venous drainage of insulin and primary enteric drainage of the exocrine secretions, 5) describing a safe outpatient percutaneous technique of pancreas allograft biopsy, 6) developing the use of glucose tolerance for rejection surveillance, and 7) managing PTX patients with biopsy-directed immunosuppression and no anti-lymphocyte induction therapy. The P-E technique has the potential to become the standard of care in the near future because it is more physiologic, normalizes carbohydrate and lipid metabolism, and minimizes complications attributed to the transplant procedure. In addition, we have been actively involved in studying new immunosuppressive regimens in order to improve and simplify the care of the PTX recipient. We believe that PTX will remain an important treatment option for IDDM until other strategies are developed that can provide equal glycemic control with less or no immunosuppression and less overall morbidity.

Eighteen years of experience with adult and pediatric liver transplantation at the University of Tennessee, Memphis

1. Since its inception, the liver program at UT Memphis has been striving to serve its population by stressing access, technical innovation, and by its focus on quality of life. The results for both adult and pediatric transplants over the past 18 years demonstrate that small and medium-sized programs can function efficiently and are valuable for their local communities. 2. Patient and graft survival rates exceeded 85% in the pediatric population in the first year with the 5-, 10-, and 15-year results above 75%. 3. Patient and graft survival rates in adults were 83% at one year, 68% at 5 years, and 60% at 10 years. 4. Innovative techniques in liver transplantation have had a dramatic impact on accessibility of pediatric recipients to liver transplantation and recently are becoming crucial for select populations of adults requiring expedited transplantation.

Development of a Web site for transplant patient education

The Internet is a global communication network used by more than 17.6 million adults as a major source of current health information. Both the number of health-related Web sites and the number of Web users are increasing exponentially as well as reports indicating a growth in the number of persons who access the Internet specifically to retrieve information about organ transplantation. However, few are using this medium for posttransplant educational or psychosocial purposes. Armed with this information, as well as a commitment from the transplant team, we chose to develop a Web-based educational program to facilitate posttransplant care for our transplant recipients. The purpose of this article is to describe the planning, development, and implementation of a Web-based education program for transplant recipients.

Long-term outcomes in simultaneous kidney-pancreas transplant recipients with portal-enteric versus systemic-bladder drainage

We retrospectively reviewed long-term outcomes in simultaneous kidney-pancreas transplant (SKPT) recipients with portal-enteric (P-E) versus systemic-bladder (S-B) drainage. Forty-five patients were alive with functioning grafts 1 year after SKPT and were followed up for a minimum of 3 years (mean, 5.9 years), including 26 patients with P-E drainage and 19 patients with S-B drainage. Recipient demographic and transplant characteristics were similar between the two groups. In both groups, hospital admissions decreased significantly with increasing time after SKPT, although significantly fewer readmissions occurred in the first year in the P-E than the S-B group. The most common reason for readmission in both groups was infection, followed by miscellaneous, surgical, and immunologic morbidity. The incidence of readmission for dehydration was significantly less in the P-E group (P < 0.01). Mean systolic and diastolic blood pressures were similar between groups, although the number of antihypertensive medications was significantly less in the S-B group. Although fasting C-peptide levels were significantly greater in the S-B group, the two groups were similar with regard to carbohydrate (fasting serum glucose, hemoglobin A(1c)) and lipid (total cholesterol) metabolism. Renal and pancreas allograft functions were similar between the two groups. At 1 year post-SKPT, stabilization in most diabetic complications was reported. Four quality-of-life surveys that provided 29 scores were completed 6 to 24 months (mean, 18.5 months) after SKPT. Improved quality of life was reported in all but one of the scales, with many dimensions showing significant improvements. At 3 years after SKPT, no activity limitation was reported in 76% of patients with P-E drainage versus 53% with S-B drainage (P = 0.11). Five-year actual patient, kidney, and pancreas graft survival rates after P-E versus S-B drainage are 92% and 84%, 81% and 79%, and 88% and 74%, respectively (P = not significant). SKPT with P-E drainage is a safe and effective method to treat advanced diabetic nephropathy and is associated with decreasing morbidity, improving rehabilitation and quality of life, and stablizing metabolic function over time. The long-term prognosis after the first year is excellent and at least similar to the results achieved with S-B drainage.

The effect of gut metabolism on tacrolimus bioavailability in renal transplant recipients

BACKGROUND

Tacrolimus, a substrate of CYP3A, has low and variable bioavailability similar to cyclosporine. Co-administration of ketoconazole, potent inhibitor of gut and hepatic CYP3A, has been shown to increase tacrolimus bioavailability in healthy volunteers. The purpose of this study is to assess the role of gut metabolism in the overall bioavailability of tacrolimus in a renal transplant population.

METHODS

We prospectively studied 19 adult renal transplant recipients who were receiving tacrolimus as part of a quadruple, sequential immunosuppression regimen. Each patient received tacrolimus (4-hr intravenous dose of 0.04 mg/kg between postoperative days 2 and 4). Whole blood samples were collected over 24 hr. After a 24-hr washout period, a single oral dose of ketoconazole (400 mg) was administered followed by the same intravenous dose of tacrolimus, and subsequent samples were obtained. Steady state oral pharmacokinetic profiles were obtained between 1 and 3 months after transplant while patients were receiving twice daily dosing of tacrolimus to maintain whole blood levels between 10 and 20 ng/ml. Two days later, 400 mg of ketoconazole was administered orally 2 hr before to the morning dose. Whole blood samples were collected over 12 hr.

RESULTS

In the absence of ketoconazole, 8.0% of the tacrolimus dose underwent first pass metabolism (E(H)), whereas in the presence of ketoconazole, first pass metabolism was 6.2% (P=0.01). Based on this difference in first pass metabolism, an increase of 2% in bioavailability is expected, but an increase of 47% is observed (P=0.001).

CONCLUSIONS

This indicates that the gut metabolism of tacrolimus is extensive and contributes significantly to its bioavailability.

Surgical technique for right lobe adult living donor liver transplantation without venovenous bypass or portocaval shunting and with duct-to-duct biliary reconstruction

OBJECTIVE

To report the authors' experience with adult living donor liver transplantation (ALDLT) without venovenous bypass and to describe modifications that will allow for a direct duct-to-duct biliary reconstruction.

SUMMARY BACKGROUND DATA

Adult living donor liver transplantation is being evaluated as a method to alleviate the organ shortage. Descriptions of the procedure have emphasized the use of venovenous bypass, portocaval decompression, and the mandatory use of a Roux-en-Y biliary enteric anastomosis. The authors describe a technique for ALDLT without venovenous bypass, portocaval decompression, or caval clamping in 11 recipients and describe the modifications to the procedure that may allow a duct-to-duct biliary reconstruction in certain cases.

METHODS

Between March 1999 and March 2000, 11 ALDLTs were performed at the authors' institution. All procedures were performed without venovenous bypass, portocaval decompression, or caval clamping. After a modification to the procedure, five of the last six recipients underwent biliary reconstruction with a direct duct-to-duct anastomosis. Data regarding donor, recipient, and graft survival, complications, and graft function were collected.

RESULTS

Recipients comprised five women and six men, mean age 48 years. Donors comprised five women and six men, mean age 36.5 years. Donor to recipient relationships included sibling, spouse, son, and daughter. Indications for transplantation were hepatitis C, hepatitis C with hepatocellular carcinoma, primary biliary cirrhosis, primary sclerosing cholangitis, ethanol, and cryptogenic. No case required venovenous bypass or portocaval shunting. The right hepatic vein of the donor graft was anastomosed to the confluence of the left and middle hepatic veins in all cases. All donors are alive and well, with no adverse complications reported. Recipient and graft survival rates were 91% and 82%, respectively, for ALDLT versus 92% and 92% for recipients of cadaveric organs during the same time period. One recipient died of multiple organ failure and sepsis. Biliary reconstruction was performed by Roux-en-Y hepaticojejunostomy in the six cases. In five of the last six recipients, direct duct-to-duct biliary reconstruction with a T tube was used. No anastomotic leaks or strictures occurred in the patients undergoing duct-to-duct reconstruction.

CONCLUSIONS

Adult living donor liver transplantation can be performed safely and may help alleviate the organ shortage. Neither venovenous bypass nor portocaval shunting is necessary to perform the procedure, and modifications to both the donor and recipient hepatectomy procedures may allow biliary reconstruction to be performed by a direct duct-to-duct anastomosis in selected cases.