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.

Symptomatic BK Virus Infection Is Associated With Kidney Function Decline and Poor Overall Survival in Allogeneic Hematopoietic Stem Cell Recipients.

Nephropathy due to BK virus (BKV) infection is an evolving challenge in patients undergoing hematopoietic stem cell transplantation (HSCT). We hypothesized that BKV infection was a marker of kidney function decline and a poor prognostic factor in HSCT recipients who experience this complication. In this retrospective study, we analyzed all patients who underwent their first allogeneic HSCT at our institution between 2004 and 2012. We evaluated the incidence of persistent kidney function decline, which was defined as a confirmed reduction in estimated glomerular filtration rate of at least 25% from baseline using the Chronic Kidney Disease Epidemiology equation. Cox proportional hazard regression was used to model the cause-specific hazard of kidney function decline, and the Fine-Gray method was used to account for the competing risks of death. Among 2477 recipients of a first allogeneic HSCT, BK viruria was detected in 25% (n = 629) and kidney function decline in 944 (38.1%). On multivariate analysis, after adjusting for age, sex, acute graft-versus-host disease (GVHD), chronic GVHD, preparative conditioning regimen, and graft source, BK viruria remained a significant risk factor for kidney function decline (p < 0.001). In addition, patients with BKV infection and kidney function decline experienced worse overall survival. After allogeneic HSCT, BKV infection was strongly and independently associated with subsequent kidney function decline and worse patient survival after HSCT.

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-ß (TRß)-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 ß-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 TRß 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 ß-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.

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).

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.

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.

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.

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.

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.

Transplantation for Hepatocellular Carcinoma: Is There a Tumor Size Limit?

BACKGROUND: The advent of tumor-size-based criteria (Milan and University of California, San Francisco [UCSF]) for the transplantation of hepatocellular carcinomas (HCC) has facilitated tumor patients' access to transplantation. Recent success in transplanting patients with larger tumors (beyond UCSF) necessitates an understanding of the patient, the tumor, and biological criteria that determine successful outcomes for HCC transplantation across all size criteria. METHODS: We analyzed 11,928 patients who received OLT between 2002 and 2013 from the United Network for Organ Sharing Standard Transplant Analysis and Research file. Clinical outcomes were compared by tumor size at transplant; Milan (n = 11,555), beyond Milan within UCSF (n = 291), and beyond both Milan and UCSF (n = 82). A statistical analysis was conducted to determine the factors impacting survival. RESULTS: There were no statistically significant differences in the 1-, 3-, and 5-year survival rates between the 3 patient groups (within Milan 91.1%, 74.8%, and 60.3%; beyond Milan within UCSF, 92.7%, 71.1%, and 51.6%; and beyond Milan and UCSF 95.8%, 75.9%, and 58.1%). In a multivariate analysis, factors significantly affecting survival included, AA race, AFP >3000, and hepatitis C infection, while age, diabetes and largest tumor diameter had a more modest impact. Total tumor burden and time to transplantation were not significant predictors of survival. CONCLUSIONS: These data indicate that, based on current clinical selection criteria, a small number of large tumors can be successfully treated by transplantation and points to the need to include markers of HCC biologic behavior beyond size and tumor burden to transplant criteria.

Treatment of Refractory Gastrointestinal Bleeding in Patients With Portal Hypertension: A Case Series and Treatment Algorithm.

In patients with portal hypertension, ectopic varices can develop at any site along the gastrointestinal tract outside the classically described gastroesophageal location. Like esophageal variceal hemorrhage, bleeding from ectopic varices can be life-threatening. Diagnosis and treatment of ectopic varices can be challenging; to date, no effective treatment algorithm has been described. A systematic teamwork approach to diagnosing and treatment of ectopic varices is required to successfully manage hemorrhage from ectopic varices.

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.

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.

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 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.

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.

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.