Tocilizumab in chronic active antibody-mediated rejection: rationale and protocol of an in-progress randomized controlled open-label multi-center trial (INTERCEPT study).

BACKGROUND: Chronic active antibody-mediated rejection (caAMR) in kidney transplants is associated with irreversible tissue damage and a leading cause of graft loss in the long-term. However, the treatment for caAMR remains a challenge to date. Recently, tocilizumab, a recombinant humanized monoclonal antibody directed against the human interleukin-6 (IL-6) receptor, has shown promise in the treatment of caAMR. However, it has not been systematically investigated so far underscoring the need for randomized controlled studies in this area. METHODS: The INTERCEPT study is an investigator-driven randomized controlled open-label multi-center trial in kidney transplant recipients to assess the efficacy of tocilizumab in the treatment of biopsy-proven caAMR. A total of 50 recipients with biopsy-proven caAMR at least 12 months after transplantation will be randomized to receive either tocilizumab (n = 25) added to our standard of care (SOC) maintenance treatment or SOC alone (n = 25) for a period of 24 months. Patients will be followed for an additional 12 months after cessation of study medication. After the inclusion biopsies at baseline, protocol kidney graft biopsies will be performed at 12 and 24 months. The sample size calculation assumed a difference of 5 ml/year in slope of estimated glomerular filtration rate (eGFR) between the two groups for 80% power at an alpha of 0.05. The primary endpoint is the slope of eGFR at 24 months after start of treatment. The secondary endpoints include assessment of the following at 12, 24, and 36 months: composite risk score iBox, safety, evolution and characteristics of donor-specific antibodies (DSA), graft histology, proteinuria, kidney function assessed by measured GFR (mGFR), patient- and death-censored graft survival, and patient-reported outcomes that include transplant-specific well-being, adherence to immunosuppressive medications and perceived threat of the risk of graft rejection. DISCUSSION: No effective treatment exists for caAMR at present. Based on the hypothesis that inhibition of IL-6 receptor by tocilizumab will reduce antibody production and reduce antibody-mediated damage, our randomized trial has a potential to provide evidence for a novel treatment strategy for caAMR, therewith slowing the decline in graft function in the long-term. TRIAL REGISTRATION: ClinicalTrials.gov NCT04561986. Registered on September 24, 2020.

Long-term Prolonged-release Tacrolimus-based Immunosuppression in De Novo Kidney Transplant Recipients: 5-Y Prospective Follow-up of Patients in the ADVANCE Study.

Although prolonged-release tacrolimus (PR-T) is widely approved for posttransplantation immunosuppression in kidney recipients, large-scale studies are required to assess long-term outcomes. We present follow-up data from the Advagraf-based Immunosuppression Regimen Examining New Onset Diabetes Mellitus in Kidney Transplant Recipients (ADVANCE) trial, in which kidney transplant patients (KTPs) received corticosteroid minimization with PR-T. Methods: ADVANCE was a 24-wk, randomized, open-label, phase-4 study. De novo KTPs received PR-T with basiliximab and mycophenolate mofetil and were randomized to receive an intraoperative corticosteroid bolus plus tapered corticosteroids until day 10 (arm 1) or an intraoperative corticosteroid bolus (arm 2). In this 5-y, noninterventional follow-up, patients received maintenance immunosuppression according to standard practice. The primary endpoint was graft survival (Kaplan-Meier). Secondary endpoints included patient survival, biopsy-confirmed acute rejection-free survival, and estimated glomerular filtration rate (4-variable modification of diet in renal disease). Results: Follow-up study included 1125 patients. Overall graft survival at 1 and 5 y posttransplantation was 93.8% and 88.1%, respectively, and was similar between treatment arms. At 1 and 5 y, patient survival was 97.8% and 94.4%, respectively. Five-year graft and patient survival rates in KTPs who remained on PR-T were 91.5% and 98.2%, respectively. Cox proportional hazards analysis demonstrated similar risk of graft loss and death between treatment arms. Five-year biopsy-confirmed acute rejection-free survival was 84.1%. Mean ± standard deviation values of estimated glomerular filtration rate were 52.7 ± 19.5 and 51.1 ± 22.4 mL/min/1.73 m2 at 1 and 5 y, respectively. Fifty adverse drug reactions were recorded, probably tacrolimus-related in 12 patients (1.5%). Conclusions: Graft survival and patient survival (overall and for KTPs who remained on PR-T) were numerically high and similar between treatment arms at 5 y posttransplantation.

The role of dendrin in IgA nephropathy.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) and its systemic variant IgA vasculitis (IgAV) damage the glomeruli, resulting in proteinuria, hematuria and kidney impairment. Dendrin is a podocyte-specific protein suggested to be involved in the pathogenesis of IgAN. Upon cell injury, dendrin translocates from the slit diaphragm to the nucleus, where it is suggested to induce apoptosis and cytoskeletal changes, resulting in proteinuria and accelerated disease progression in mice. Here we investigated gene and protein expression of dendrin in relation to clinical and histopathological findings to further elucidate its role in IgAN/IgAV. METHODS: Glomerular gene expression was measured using microarray on 30 IgAN/IgAV patients, 5 patients with membranous nephropathy (MN) and 20 deceased kidney donors. Dendrin was spatially evaluated on kidney tissue sections by immunofluorescence (IF) staining (IgAN patients, n = 4; nephrectomized kidneys, n = 3) and semi-quantified by immunogold electron microscopy (IgAN/IgAV patients, n = 21; MN, n = 5; living kidney donors, n = 6). Histopathological grading was performed according to the Oxford and Banff classifications. Clinical data were collected at the time of biopsy and follow-up. RESULTS: Dendrin mRNA levels were higher (P = .01) in IgAN patients compared with MN patients and controls and most prominently in patients with preserved kidney function and fewer chronic histopathological changes. Whereas IF staining did not differ between groups, immunoelectron microscopy revealed that a higher relative nuclear dendrin concentration in IgAN patients was associated with a slower annual progression rate and milder histopathological changes. CONCLUSION: Dendrin messenger RNA levels and relative nuclear protein concentrations are increased and associated with a more benign phenotype and progression in IgAN/IgAV patients.

Current Practices on Diagnosis, Prevention and Treatment of Post-Transplant Lymphoproliferative Disorder in Pediatric Patients after Solid Organ Transplantation: Results of ERN TransplantChild Healthcare Working Group Survey.

(1) Background: Post-transplant lymphoproliferative disease (PTLD) is a significant complication of solid organ transplantation (SOT). However, there is lack of consensus in PTLD management. Our aim was to establish a present benchmark for comparison between international centers and between various organ transplant systems and modalities; (2) Methods: A cross-sectional questionnaire of relevant PTLD practices in pediatric transplantation was sent to multidisciplinary teams from 17 European center members of ERN TransplantChild to evaluate the centers' approach strategies for diagnosis and treatment and how current practices impact a cross-sectional series of PTLD cases; (3) Results: A total of 34 SOT programs from 13 European centers participated. The decision to start preemptive treatment and its guidance was based on both EBV viremia monitoring plus additional laboratory methods and clinical assessment (61%). Among treatment modalities the most common initial practice at diagnosis was to reduce the immunosuppression (61%). A total of 126 PTLD cases were reported during the period 2012-2016. According to their histopathological classification, monomorphic lesions were the most frequent (46%). Graft rejection after PTLD remission was 33%. Of the total cases diagnosed with PTLD, 88% survived; (4) Conclusions: There is still no consensus on prevention and treatment of PTLD, which implies the need to generate evidence. This might successively allow the development of clinical guidelines.

Pediatric transplantation in Europe during the COVID-19 pandemic: Early impact on activity and healthcare.

The current pandemic SARS-CoV-2 has required an unusual allocation of resources that can negatively impact chronically ill patients and high-complexity procedures. Across the European Reference Network on Pediatric Transplantation (ERN TransplantChild), we conducted a survey to investigate the impact of the COVID-19 outbreak on pediatric transplant activity and healthcare practices in both solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT). The replies of 30 professionals from 18 centers in Europe were collected. Twelve of 18 centers (67%) showed a reduction in their usual transplant activity. Additionally, outpatient visits have been modified and restricted to selected ones, and the use of telemedicine tools has increased. Additionally, a total of 14 COVID-19 pediatric transplanted patients were identified at the time of the survey, including eight transplant recipients and six candidates for transplantation. Only two moderate-severe cases were reported, both in HSCT setting. These survey results demonstrate the limitations in healthcare resources for pediatric transplantation patients during early stages of this pandemic. COVID-19 disease is a major worldwide challenge for the field of pediatric transplantation, where there will be a need for systematic data collection, encouraging regular discussions to address the long-term consequences for pediatric transplantation candidates, recipients, and their families.

[The first kidney exchanges between two Scandinavian countries have been performed]. / De första njurbytena mellan två skandinaviska länder är gjorda.

This article describes the Scandinavian expansion of the previously described kidney exchange program STEP, and the first two exchanges that were performed between two Scandinavian countries late in 2019. All surgical procedures were performed simultaneously and/or coordinated at different hospitals in Scandinavia and the kidney grafts were transported between the participating units. Four weeks after surgery, all recipients had a good and stable kidney function and all donors had recovered.

Prostate cancer in kidney transplant recipients - a nationwide register study.

OBJECTIVE: To investigate whether post-transplantation immunosuppression negatively affects prostate cancer outcomes in male kidney transplant recipients. PATIENTS AND METHODS: We used the Swedish Renal Register and the National Prostate Cancer Register to identify all kidney transplantation recipients diagnosed with prostate cancer in Sweden 1998-2016. After linking these registers with Prostate Cancer Database Sweden (PCBaSe), a case-control study was designed to compare time period and risk category-specific probabilities of a prostate cancer diagnosis amongst kidney transplantation recipients versus the male general population. The registers did not include information about the specific immunosuppression agent used in all transplantation recipients. Data from PCBaSe were used to compare prostate cancer characteristics at diagnosis and survival for patients with prostate cancer with versus without a kidney transplant. Propensity score matching, Cox regression analysis and Fisher's exact test were used and 95% confidence intervals (CIs) calculated. RESULTS: Almost half of the 133 kidney transplantation recipients were transplanted before the mid-1990s, when PSA testing became common. The transplant recipients were not more likely than age-matched control men to be diagnosed with any (odds ratio [OR] 0.84, 95% CI 0.70-0.99) or high-risk or metastatic prostate cancer (OR 0.84, 95% CI 0.62-1.13). None of the ORs for the different categories of prostate cancer increased with time since transplantation. Cancer characteristics at the time of diagnosis and cancer-specific survival were similar amongst transplant recipients and the control group of 665 men diagnosed with prostate cancer without a kidney transplant. CONCLUSIONS: This Swedish nationwide, register-based study gave no indication that immunosuppression after kidney transplantation increases the risk of prostate cancer or adversely affects prostate cancer outcomes. The study suggests that men with untreated low-grade prostate cancer can be accepted for transplantation.

First European Case of Simultaneous Liver and Pancreas Transplantation as Treatment of Wolcott-Rallison Syndrome in a Small Child.

BACKGROUND: The concept of organ transplantation as treatment for complex genetic conditions, including Wolcott-Rallison syndrome (WRS), continues to show promise. Liver transplantation is essential for survival of patients with WRS, and pancreas transplantation cures their type I diabetes mellitus. METHODS: The recipient, a 3-year-old girl weighing 14 kg at the time of transplantation, suffered from major complications of WRS, including repetitive liver failure episodes and poorly controlled diabetes. The patient underwent a nonacute, combined, simultaneous liver and pancreas transplantation from a pediatric donor without using the en bloc technique. RESULTS: Well-preserved graft functions at 2-year follow-up with normal liver and pancreas function. CONCLUSIONS: This is the first case report of simultaneous liver and pancreas transplantation as treatment of WRS in a small child in Europe. Two-year follow-up demonstrates that organ transplantation can halt life-threating recurrent liver failure episodes and cure type 1 diabetes.

Whole genome DNA sequencing provides an atlas of somatic mutagenesis in healthy human cells and identifies a tumor-prone cell type.

BACKGROUND: The lifelong accumulation of somatic mutations underlies age-related phenotypes and cancer. Mutagenic forces are thought to shape the genome of aging cells in a tissue-specific way. Whole genome analyses of somatic mutation patterns, based on both types and genomic distribution of variants, can shed light on specific processes active in different human tissues and their effect on the transition to cancer. RESULTS: To analyze somatic mutation patterns, we compile a comprehensive genetic atlas of somatic mutations in healthy human cells. High-confidence variants are obtained from newly generated and publicly available whole genome DNA sequencing data from single non-cancer cells, clonally expanded in vitro. To enable a well-controlled comparison of different cell types, we obtain single genome data (92% mean coverage) from multi-organ biopsies from the same donors. These data show multiple cell types that are protected from mutagens and display a stereotyped mutation profile, despite their origin from different tissues. Conversely, the same tissue harbors cells with distinct mutation profiles associated to different differentiation states. Analyses of mutation rate in the coding and non-coding portions of the genome identify a cell type bearing a unique mutation pattern characterized by mutation enrichment in active chromatin, regulatory, and transcribed regions. CONCLUSIONS: Our analysis of normal cells from healthy donors identifies a somatic mutation landscape that enhances the risk of tumor transformation in a specific cell population from the kidney proximal tubule. This unique pattern is characterized by high rate of mutation accumulation during adult life and specific targeting of expressed genes and regulatory regions.

Management of BK-virus infection - Swedish recommendations.

BK-virus (BKV) associated nephropathy (BKVAN) and BKV associated haemorrhagic cystitis (HC) are complications of BKV infection/reactivation in renal and allogeneic haematopoietic stem cell transplantation (HSCT) patients, respectively. The task of how to manage these diseases was given to the chair by the Swedish Reference Group for Antiviral Therapy (RAV). After individual contributions by members of the working group, consensus discussions were held in a meeting on 23 January 2018 arranged by RAV. Thereafter, the recommendations were published in Swedish on November 2018. The current translation to English has been approved by all co-authors. High BKV serum levels suggest an increased risk for BKVAN and potential graft failure. For detection of BKVAN, careful monitoring of BKV DNA levels in serum or plasma is recommended the first year after renal transplantation and when increased creatinine serum levels of unknown cause are observed. Notably, a renal biopsy is mandatory for diagnosis. To reduce the risk for progression of BKVAN, there is no specific treatment, and tailored individual decrease of immunosuppression is recommended. For BKV-HC, BKV monitoring is not recommended, since BK-viruria frequently occurs in HSCT patients and the predictive value of BKV in plasma/serum has not been determined. However, the risk for BKV-HC is higher for patients undergoing myeloablative conditioning, having an unrelated, HLA-mismatched, or a cord blood donor, and awareness of the increased risk and early intervention may benefit the patients. Also for BKV-HC, no specific therapy is available. Symptomatic treatment, e.g. forced diuresis and analgesics could be of use.

Pronase independent flow cytometry crossmatching of rituximab treated patients.

ABO-incompatible (ABOi) kidney transplantation has become an established strategy to increase the number of available living donors. At our center, the conditioning protocol for ABOi patients is based on anti-A/B antibody removal and depletion of B cells with the anti-CD20 mAb rituximab (Mabthera®). It is known that even low amounts of remaining rituximab in serum of patients results in false positive B cell cross match results, masking detection of potentially harmful donor human leukocyte antigen (HLA) specific antibodies. Treatment of donor cells with high concentrations (>1 mg/mL) of pronase is currently standard procedure for elimination of rituximab (RIT) interference. It is, however, troublesome that recent reports indicate that pronase treatment per se can induce incorrect flow cytometry cross match (FCXM) results. The aim of this study was to evaluate an alternative pronase-free FCXM for crossmatching of patients treated with rituximab. FCXM with an anti-RIT monoclonal antibody (mAb) pre-blocking step were evaluated on normal human sera (NHS) and patient sera supplemented with RIT. NHS supplemented with RIT or patient sera, without donor specific antibodies (DSA), resulted in high B cell median channel shift (>200 IgG) above background. This shift was eliminated by a serum pre-blocking step with 2-fold excess of anti-RIT (clone MB2A4). Blocking with anti-RIT did not influence the T cells crossmatch results. We present data supporting proof-of-concept that blocking with anti-RIT antibody prior to XM can enable reliable detection of anti-HLA class I and II donor specific antibodies without use of pronase treated donor cells.

IgG Endopeptidase in Highly Sensitized Patients Undergoing Transplantation.

BACKGROUND: Donor-specific antibodies create an immunologic barrier to transplantation. Current therapies to modify donor-specific antibodies are limited and ineffective in the most highly HLA-sensitized patients. The IgG-degrading enzyme derived from Streptococcus pyogenes (IdeS), an endopeptidase, cleaves human IgG into F(ab')2 and Fc fragments inhibiting complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, which suggests that IdeS might be useful for desensitization. We report on the combined experience of two independently performed open-label, phase 1-2 trials (conducted in Sweden and the United States) that assessed the efficacy of IdeS with regard to desensitization and transplantation of a kidney from an HLA-incompatible donor. METHODS: We administered IdeS to 25 highly HLA-sensitized patients (11 patients in Uppsala or Stockholm, Sweden, and 14 in Los Angeles) before the transplantation of a kidney from an HLA-incompatible donor. Frequent monitoring for adverse events, outcomes, donor-specific antibodies, and renal function was performed, as were renal biopsies. Immunosuppression after transplantation consisted of tacrolimus, mycophenolate mofetil, and glucocorticoids. Patients in the U.S. study also received intravenous immune globulin and rituximab after transplantation to prevent antibody rebound. RESULTS: Recipients in the U.S. study had a significantly longer cold ischemia time (the time elapsed between procurement of the organ and transplantation), a significantly higher rate of delayed graft function, and significantly higher levels of class I donor-specific antibodies than those in the Swedish study. A total of 38 serious adverse events occurred in 15 patients (5 events were adjudicated as being possibly related to IdeS). At transplantation, total IgG and HLA antibodies were eliminated. A total of 24 of 25 patients had perfusion of allografts after transplantation. Antibody-mediated rejection occurred in 10 patients (7 patients in the U.S. study and 3 in the Swedish study) at 2 weeks to 5 months after transplantation; all these patients had a response to treatment. One graft loss, mediated by non-HLA IgM and IgA antibodies, occurred. CONCLUSIONS: IdeS reduced or eliminated donor-specific antibodies and permitted HLA-incompatible transplantation in 24 of 25 patients. (Funded by Hansa Medical; ClinicalTrials.gov numbers, NCT02224820 , NCT02426684 , and NCT02475551 .).

CDKN2A/p16INK4a expression is associated with vascular progeria in chronic kidney disease.

Patients with chronic kidney disease (CKD) display a progeric vascular phenotype linked to apoptosis, cellular senescence and osteogenic transformation. This has proven intractable to modelling appropriately in model organisms. We have therefore investigated this directly in man, using for the first time validated cellular biomarkers of ageing (CDKN2A/p16INK4a, SA-ß-Gal) in arterial biopsies from 61 CKD patients undergoing living donor renal transplantation. We demonstrate that in the uremic milieu, increased arterial expression of CDKN2A/p16INK4a associated with vascular progeria in CKD, independently of chronological age. The arterial expression of CDKN2A/p16INK4a was significantly higher in patients with coronary calcification (p=0.01) and associated cardiovascular disease (CVD) (p=0.004). The correlation between CDKN2A/p16INK4a and media calcification was statistically significant (p=0.0003) after correction for chronological age. We further employed correlate expression of matrix Gla protein (MGP) and runt-related transcription factor 2 (RUNX2) as additional pathognomonic markers. Higher expression of CDKN2A/p16INK4a, RUNX2 and MGP were observed in arteries with severe media calcification. The number of p16INK4a and SA-ß-Gal positive cells was higher in biopsies with severe media calcification. A strong inverse correlation was observed between CDKN2A/p16INK4a expression and carboxylated osteocalcin levels. Thus, impaired vitamin K mediated carboxylation may contribute to premature vascular senescence.

Bone mineral density of extremities is associated with coronary calcification and biopsy-verified vascular calcification in living-donor renal transplant recipients.

Chronic kidney disease (CKD) mineral and bone disorders (CKD-MBD) may lead to low bone mineral density (BMD) and vascular calcification (VC), but links to the latter are unclear. Here we investigated associations between BMD, coronary artery calcium (CAC) scores, and histological signs of VC in end-stage renal disease (ESRD) patients undergoing living-donor kidney transplantation (LD-Rtx). In 66 ESRD patients (median age 45 years, 68% males), BMD (by dual-energy X-ray absorptiometry, DXA), CAC score (by computed tomography, CT; n = 54), and degree of VC score (graded by histological examination of epigastric artery specimens collected at LD-Rtx; n = 55) were assessed at the time of LD-Rtx. Of the patients, 26% had osteopenia and 7% had osteoporosis. Of those undergoing artery biopsy, 16% had extensive VC, and of those undergoing CT 28% had high CAC score (>100 Agatston units). CAC scores correlated with BMD of legs and pelvis. BMDs of leg and pelvic sub-regions were significantly lower in patients with extensive VC. In multivariate regression analysis adjusted for age and gender, lower BMD of leg sub-region was associated with CAC score >100 AUs and extensive VC, and patients with extensive VC had significantly higher CAC score. Both high CAC and extensive VC were independently predicted by low BMD of legs. Low BMD has the potential to identify ESRD patients at risk of vascular calcification.

Increased circulating sclerostin levels in end-stage renal disease predict biopsy-verified vascular medial calcification and coronary artery calcification.

Sclerostin, an osteocyte-derived inhibitor of bone formation, is linked to mineral bone disorder. In order to validate its potential as a predictor of vascular calcification, we explored associations of circulating sclerostin with measures of calcification in 89 epigastric artery biopsies from patients with end-stage renal disease. Significantly higher sclerostin levels were found in the serum of patients with epigastric and coronary artery calcification (calcification score 100 or more). In Spearman's rank correlations, sclerostin levels significantly associated with age, intact parathyroid hormone, bone-specific alkaline phosphatase, and percent calcification. Multivariable regression showed that age, male gender, and sclerostin each significantly associated with the presence of medial vascular calcification. Receiver operating characteristic curve analysis showed that sclerostin (AUC 0.68) predicted vascular calcification. Vascular sclerostin mRNA and protein expressions were low or absent, and did not differ between calcified and non-calcified vessels, suggesting that the vasculature is not a major contributor to circulating levels. Thus, high serum sclerostin levels associate with the extent of vascular calcification as evaluated both by coronary artery CT and scoring of epigastric artery calcification. Among circulating biomarkers of mineral bone disorder, only sclerostin predicted vascular calcification.

Islet engraftment and revascularization in clinical and experimental transplantation.

Proper revascularization after transplantation is assumed to be crucial for appropriate islet graft function. We developed a novel noninvasive imaging method, based on adenoviral transduction of islets with a hypoxia responsive reporter gene, for continuous in vivo monitoring of hypoxia in islet grafts in a mouse model. In addition, morphological data were obtained from a deceased patient previously subject to intraportal transplantation. We detected only transient hypoxia in a minority of the animals transplanted. Importantly, a clear response to hypoxia was observed in vitro after removal of the islet grafts on day 28 after transplantation. Also, the morphological data from the deceased patient demonstrated an extensive revascularization of the transplanted islets. In fact, no differences could be seen between native islets, in pancreas biopsies taken prior to islet isolation, and transplanted islets regarding the number, distribution, and shape of the blood vessels. However, fewer small islets (diameter <39 µm) were found in the liver compared to those found in native pancreases. Notably, an absolute majority of the transplanted islets were found remaining within the venous lumen, in direct contact with the vessel wall. In conclusion, the results presented show less pronounced islet graft hypoxia after subcapsular transplantation than previously reported using more invasive methods. Also, formation of an extensive intraislet capillary network, similar to that seen in native islets in the pancreas, was seen after clinical islet transplantation.

Oxygen-charged HTK-F6H8 emulsion reduces ischemia-reperfusion injury in kidneys from brain-dead pigs.

BACKGROUND: Prolonged cold ischemia is frequently associated with a greater risk of delayed graft function and enhanced graft failure. We hypothesized that media, combining a high oxygen-dissolving capacity with specific qualities of organ preservation solutions, would be more efficient in reducing immediate ischemia-reperfusion injury from organs stored long term compared with standard preservation media. METHODS: Kidneys retrieved from brain-dead pigs were flushed using either cold histidine-tryptophan-ketoglutarate (HTK) or oxygen-precharged emulsion composed of 75% HTK and 25% perfluorohexyloctane. After 18 h of cold ischemia the kidneys were transplanted into allogeneic recipients and assessed for adenosine triphosphate content, morphology, and expression of genes related to hypoxia, environmental stress, inflammation, and apoptosis. RESULTS: Compared with HTK-flushed kidneys, organs preserved using oxygen-precharged HTK-perfluorohexyloctane emulsion had increased elevated adenosine triphosphate content and a significantly lower gene expression of hypoxia inducible factor-1α, vascular endothelial growth factor, interleukin-1α, tumor necrosis factor-α, interferon-α, JNK-1, p38, cytochrome-c, Bax, caspase-8, and caspase-3 at all time points assessed. In contrast, the mRNA expression of Bcl-2 was significantly increased. CONCLUSIONS: The present study has demonstrated that in brain-dead pigs the perfusion of kidneys with oxygen-precharged HTK-perfluorohexyloctane emulsion results in significantly reduced inflammation, hypoxic injury, and apoptosis and cellular integrity and energy content are well maintained. Histologic examination revealed less tubular, vascular, and glomerular changes in the emulsion-perfused tissue compared with the HTK-perfused counterparts. The concept of perfusing organs with oxygen-precharged emulsion based on organ preservation media represents an efficient alternative for improved organ preservation.

Preapheresis immunosuppressive induction: necessary or harmful?

In ABO-incompatible kidney transplantation, only a few studies have addressed the necessity, duration, and content of immunosuppressive induction therapy. At our center (Karolinska Institute, Stockholm, Sweden), using a preconditioning regimen consisting of 13 days of tacrolimus, mycophenolate mofetil, and prednisolone, we have investigated both short- and long-term renal allograft function (up to 28 days and 1 year after transplantation, respectively) and correlated them to tacrolimus 12-hr trough levels. In summary, during the first 28 days after transplantation, renal allograft function in the ABO-incompatible group was impaired when compared with that observed in the ABO-compatible group. One possible explanation for this finding is the prolonged pretransplantation exposure to tacrolimus in the ABO-incompatible group, resulting in tacrolimus-associated renal toxicity, which slows the reduction in plasma creatinine. In fact, the day before, and also immediately after, the transplantation (for the first 3-4 postoperative days), the tacrolimus 12-hr trough levels in the ABO-incompatible group were greater than in the ABO-compatible group. Possibly, a shorter pretreatment period with tacrolimus or a reduced target tacrolimus trough level could eliminate this difference in postoperative renal allograft function. However, 1 year after transplantation, kidney allograft function in the two study groups was similar.

The efficacy of CD40 ligand blockade in discordant pig-to-rat islet xenotransplantation is correlated with an immunosuppressive effect of immunoglobulin.

BACKGROUND: The authors' aim was to evaluate the efficacy of immunosuppression with monoclonal anti-CD40 ligand antibodies (aCD40L) or nonspecific polyclonal intravenous immunoglobulin (IVIG) in the pig-to-rat islet xenotransplantation model. METHODS: Fetal porcine islet-like cell clusters were transplanted under the kidney capsule of nondiabetic rats. All antibodies were administered alone or in combination with cyclosporine A (CsA). In addition, some animals were administered antibodies plus tacrolimus (TAC) or sirolimus (SIR). Twelve days after transplantation, islet xenograft survival and rejection were evaluated using immunohistochemistry. RESULTS: aCD40L plus CsA had a pronounced inhibitory effect on islet xenograft rejection for up to 12 days after transplantation. Unexpectedly, treatment with a monoclonal control antibody (anti-keyhole limpet hemocyanin [aKLH]) plus CsA had a similar inhibitory effect. Furthermore, a similar inhibition of islet xenograft rejection was observed also in animals administered IVIG plus CsA. Monotherapy with aCD40L, aKLH, IVIG, or CsA had no effect on the rejection process. Also, when aCD40L or aKLH was administered together with TAC, islet xenograft rejection was inhibited. There was no marked difference compared with rats treated with aCD40L or aKLH and CsA. Immunosuppression with aCD40L or aKLH in combination with SIR also inhibited pig-to-rat islet xenograft rejection, but the protective effect was not as pronounced. CONCLUSIONS: Immunosuppression with high doses of antibodies, monoclonal or polyclonal, in combination with CsA or TAC inhibits pig-to-rat islet xenograft rejection. No specific effect of co-stimulatory blockade with aCD40L could be observed. Instead, the results indicate a nonspecific immunosuppressive effect of high doses of antibodies in this model.

No transmission of porcine endogenous retrovirus after transplantation of adult porcine islets into diabetic nude mice and immunosuppressed rats.

BACKGROUND: The aim of this study was to investigate whether transmission of porcine endogenous retrovirus (PERV) occurs in a model of diabetes reversal by the xenotransplantation of adult porcine islets (APIs) into immunoincompetent diabetic rodents. METHODS: Black-6 nu/nu mice and Lewis rats were immunosuppressed with cyclosporin A (CsA) and FTY 720, and rendered diabetic with streptozotocin. Purified APIs were transplanted into the renal subcapsular space; 5,000 islet equivalents (IEQs) were used in the nude mice (n = 4) and 40,000 IEQs in the rats (n = 4). The nude mice were sacrificed at 75 days after transplantation. In order to confirm chronic xenograft function, the graft-bearing kidney was removed prior to sacrifice. The rats were followed until xenograft rejection, at which time they were sacrificed. Immediately after sacrifice, tissue samples (liver, spleen, and small intestine) were taken for analysis. Quantitative polymerase chain reaction (PCR) was used to assess evidence of PERV transmission, and porcine cell chimerism. RESULTS: All animals became normoglycemic within 48 h of transplantation. The nude mice remained normoglycemic during the 75-day study period, with removal of the graft-bearing kidney resulting in prompt hyperglycemia. The rats remained normoglycemic until xenograft rejection, which occurred at 66 +/- 28 days. Despite the evidence of porcine cell microchimerism in recipients, real-time PCR detected no evidence of PERV transmission in any of the tissue specimens tested. CONCLUSIONS: There was no evidence of PERV transmission following transplantation of pig islets into diabetic nude mice and immunosuppressed rats.