Kidney Tissue Proteome Profiles in Short Versus Long Duration of Delayed Graft Function - A Pilot Study in Donation After Circulatory Death Donors

Introduction

Delayed graft function (DGF) is often defined as the need for dialysis treatment in the first week after a kidney transplantation. This definition, though readily applicable, is generic and unable to distinguish between "types" of DGF or time needed to recover function that may also significantly affect longer-term outcomes. We aimed to profile biological pathways in donation after circulatory death (DCD) kidney donors that correlate with DGF and different DGF durations.

Methods

A total of N = 30 DCD kidney biopsies were selected from the UK Quality in Organ Donation (QUOD) biobank and stratified according to DGF duration (immediate function, IF n = 10; "short-DGF" (1-6 days), SDGF n = 10; "long-DGF" (7-22 days), LDGF n = 10). Samples were matched for donor and recipient demographics and analyzed by label-free quantitative (LFQ) proteomics, yielding identification of N = 3378 proteins.

Results

Ingenuity pathway analysis (IPA) on differentially abundant proteins showed that SDGF kidneys presented upregulation of stress response pathways, whereas LDGF presented impaired response to stress, compared to IF. LDGF showed extensive metabolic deficits compared to IF and SDGF.

Conclusion

DCD kidneys requiring dialysis only in the first week posttransplant present acute cellular injury at donation, alongside repair pathways upregulation. In contrast, DCD kidneys requiring prolonged dialysis beyond 7 days present minimal metabolic and antioxidant responses, suggesting that current DGF definitions might not be adequate in distinguishing different patterns of injury in donor kidneys contributing to DGF.

Certification Training and Liver Transplant Experience Improves Liver Procurement Outcomes: The Dutch Approach

BACKGROUND

This study investigates the impact of certification training and liver transplant experience on procurement outcomes of deceased donor liver procurement in the Netherlands.

METHODS

Three groups (trainee, certified, and master) were formed, with further subdivision based on liver transplant experience. Three key outcomes-surgical injury, graft discard after injury, and donor hepatectomy duration-were analyzed.

RESULTS

There were no significant differences in surgical graft injury in the three groups (trainee, 16.9%; certified, 14.8%; master, 18.2%; P = 0.357; 2011 to 2018). The only predictor for surgical graft injury was donation after cardiac death (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.10-2.02). Of the three groups, the master group had the highest discard rate after surgical injury (trainee, 0%; certified, 1.3%; master, 2.8%; P = 0.013). Master group without liver transplant experience (OR, 3.16; 95% CI, 1.21-8.27) and male donor sex (OR, 3.58; 95% CI, 1.32-9.73) were independent risk factors for discarding livers after surgical injury. Independent predictors for shorter hepatectomy durations included donors older than 50 years (coefficient [Coeff], -7.04; 95% CI, -8.03 to -3.29; P < 0.001), and master group (Coeff, -9.84; 95% CI, -14.37 to -5.31; P < 0.001) and certified group with liver transplant experience (Coeff, -6.54; 95% CI, -10.83 to -2.26; P = 0.003). On the other hand, master group without liver transplant experience (Coeff, 5.00; 95% CI, 1.03-8.96; P = 0.014) and donation after cardiac death (Coeff, 10.81; 95% CI, 8.32-13.3; P < 0.001) were associated with longer hepatectomy durations.

CONCLUSIONS

Training and certification in abdominal organ procurement surgery were associated with a reduced discard rate for surgical injured livers and shorter hepatectomy times. The contrast between master group with and without liver transplant experience underscores the need for specialized training in this field.

Renal biopsies from donors with acute kidney injury show different molecular patterns according to the post-transplant function

The utilization of kidneys from donors with acute kidney injury (AKI) is often limited by unpredictable post-transplantation outcomes. The aim of our study was to identify protein mediators implicated in either recovery or failure of these organs. Forty kidney biopsies from donors with (20) and without AKI (20) were selected and then subdivided according to the post-transplant outcome defined as a threshold of 45 ml/min for the eGFR at 1 year from transplantation. Tissue homogenates were analysed by western blot to assess how the levels of 17 pre-selected proteins varied across the four groups. Samples from AKI kidneys with a poor outcome showed a fourfold increase in the levels of PPARg and twofold reduction of STAT1 compared to the other groups (p < 0.05). On the contrary, antioxidant enzymes including TRX1 and PRX3 were increased in the AKI kidneys with a good outcome (p < 0.05). An opposite trend was observed for the detoxifying enzyme GSTp which was significantly increased in the AKI group with poor versus good outcome (p < 0.05). The importance of lipid metabolism (PPARg) and inflammatory signals (STAT1) in the function recovery of these kidneys hints to the therapeutical targeting of the involved pathways in the setting of organ reconditioning.

Impaired O2 unloading from stored blood results in diffusion-limited O2 release at tissues: evidence from human kidneys

ABSTRACT

The volume of oxygen drawn from systemic capillaries down a partial pressure gradient is determined by the oxygen content of red blood cells (RBCs) and their oxygen-unloading kinetics, although the latter is assumed to be rapid and, therefore, not a meaningful factor. Under this paradigm, oxygen transfer to tissues is perfusion-limited. Consequently, clinical treatments to optimize oxygen delivery aim at improving blood flow and arterial oxygen content, rather than RBC oxygen handling. Although the oxygen-carrying capacity of blood is increased with transfusion, studies have shown that stored blood undergoes kinetic attrition of oxygen release, which may compromise overall oxygen delivery to tissues by causing transport to become diffusion-limited. We sought evidence for diffusion-limited oxygen release in viable human kidneys, normothermically perfused with stored blood. In a cohort of kidneys that went on to be transplanted, renal respiration correlated inversely with the time-constant of oxygen unloading from RBCs used for perfusion. Furthermore, the renal respiratory rate did not correlate with arterial O2 delivery unless this factored the rate of oxygen-release from RBCs, as expected from diffusion-limited transport. To test for a rescue effect, perfusion of kidneys deemed unsuitable for transplantation was alternated between stored and rejuvenated RBCs of the same donation. This experiment controlled oxygen-unloading, without intervening ischemia, holding all non-RBC parameters constant. Rejuvenated oxygen-unloading kinetics improved the kidney's oxygen diffusion capacity and increased cortical oxygen partial pressure by 60%. Thus, oxygen delivery to tissues can become diffusion-limited during perfusion with stored blood, which has implications in scenarios, such as ex vivo organ perfusion, major hemorrhage, and pediatric transfusion. This trial was registered at www.clinicaltrials.gov as #ISRCTN13292277.

Comparison of in-gel and in-solution proteolysis in the proteome profiling of organ perfusion solutions

PURPOSE

The organ perfusion solution (perfusate), collected at clinically and temporally significant stages of the organ preservation and transplantation process, provides a valuable insight into the biological status of an organ over time and prior to reperfusion (transplantation) in the recipient. The objective of this study was to assess two bottom-up proteomics workflows for the extraction of tryptic peptides from the perfusate.

EXPERIMENTAL DESIGN

Two different kinds of perfusate samples from kidney and liver trials were profiled using liquid chromatography-mass spectrometry (LC-MS/MS). The preparation of clean peptide mixtures for downstream analysis was performed considering different aspects of sample preparation; protein estimation, enrichment, in-gel and urea-based in-solution digestion.

RESULTS

In-solution digestion of perfusate allowed identification of the highest number of peptides and proteins with greater sequence coverage and higher confidence data in kidney and liver perfusate. Key pathways identified by gene ontology analysis included complement, coagulation and antioxidant pathways, and a number of biomarkers previously linked to ischemia-reperfusion injury were also observed in perfusate.

CONCLUSIONS

This study showed that in-solution digestion is a more efficient method for LC-MS/MS analysis of kidney and liver organ perfusion solutions. This method is also quicker and easier than in-gel digestion, allowing for greater sample throughput, with fewer opportunities for experimental error or peptide loss.

The Effect of Continuous Liver Normothermic Machine Perfusion on the Severity of Histological Bile Duct Injury

Static Cold Storage (SCS) injures the bile duct, while the effect of Normothermic Machine Perfusion (NMP) is unknown. In a sub-study of the COPE trial on liver NMP, we investigated the impact of preservation type on histological bile duct injury score (BDIS). Transplants with at least one bile duct biopsy, either at end of preservation or 1 h post-reperfusion, were considered. BDIS was determined by assessing peribiliary glands injury, stromal and mural loss, haemorrhage, and thrombosis. A bivariate linear model compared BDIS (estimate, CI) between groups. Sixty-five transplants and 85 biopsies were analysed. Twenty-three grafts were preserved with SCS and 42 with NMP, with comparable baseline characteristics except for a shorter cold ischemic time in NMP. The BDIS increased over time regardless of preservation type (p = 0.04). The BDIS estimate was higher in NMP [8.02 (7.40-8.65)] than in SCS [5.39 (4.52-6.26), p < 0.0001] regardless of time. One patient in each group developed ischemic cholangiopathy, with a BDIS of 6 for the NMP-preserved liver. In six other NMP grafts, BDIS ranged 7-12 without development of ischemic cholangiopathy. In conclusion, BDIS increases over time, and the higher BDIS in NMP did not increase ischemic cholangiopathy. Thus, BDIS may overestimate this risk after liver NMP.

Embryo mortality in a captive-bred, Critically Endangered amphibian

The Critically Endangered southern corroboree frog Pseudophryne corroboree is dependent upon captive assurance colonies for its continued survival. Although the captive breeding programme for this species has largely been successful, embryonic mortality remains high (40-90% per year). This study aimed to investigate the causes of mortality in P. corroboree embryos in the captive collection at Melbourne Zoo. During the 2021 breeding season, we investigated 108 abnormal embryos to determine the impact of infections and anatomical deformities on survival and used culture and molecular methods to identify microbes. Overall, 100% of abnormal embryos had fungal infections, and of these, 41.6% also had anatomical deformities. The mortality rate in abnormal embryos was 89.8%; however, we detected no difference in survival in any of the 3 observed fungal growth patterns or between deformed and non-deformed embryos. Sanger sequencing of the ITS region identified fungal isolates belonging to the genus Ilyonectria, the first record in a vertebrate host, and another as a Plectosphaerella sp., which is the first record of infection in an embryo. Dominant bacteria identified were of the genera Herbaspirillum and Flavobacterium; however, their role in the mortality is unknown. Fungal infection and deformities have a significant impact on embryo survival in captive-bred P. corroboree. In a species which relies on captive breeding, identifying and reducing the impacts of embryonic mortality can inform conservation efforts and improve reintroduction outcomes.

Incidence, Risk Factors, and Effect on Allograft Survival of Glomerulonephritis Post-transplantation in a United Kingdom Population: Cohort Study

Background

Post-transplant glomerulonephritis (PTGN) has been associated with inferior long-term allograft survival, and its incidence varies widely in the literature.

Methods

This is a cohort study of 7,623 patients transplanted between 2005 and 2016 at four major transplant UK centres. The diagnosis of glomerulonephritis (GN) in the allograft was extracted from histology reports aided by the use of text-mining software. The incidence of the four most common GN post-transplantation was calculated, and the risk factors for disease and allograft outcomes were analyzed.

Results

In total, 214 patients (2.8%) presented with PTGN. IgA nephropathy (IgAN), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), and membranoproliferative/mesangiocapillary GN (MPGN/MCGN) were the four most common forms of post-transplant GN. Living donation, HLA DR match, mixed race, and other ethnic minority groups were associated with an increased risk of developing a PTGN. Patients with PTGN showed a similar allograft survival to those without in the first 8 years of post-transplantation, but the results suggest that they do less well after that timepoint. IgAN was associated with the best allograft survival and FSGS with the worst allograft survival.

Conclusions

PTGN has an important impact on long-term allograft survival. Significant challenges can be encountered when attempting to analyze large-scale data involving unstructured or complex data points, and the use of computational analysis can assist.

Kidney Normothermic Machine Perfusion Can Be Used as a Preservation Technique and a Model of Reperfusion to Deliver Novel Therapies and Assess Inflammation and Immune Activation

Ischaemia-reperfusion injury (IRI) is an inevitable process in transplantation and results in inflammation and immune system activation. Alpha-1 antitrypsin (AAT) has anti-inflammatory properties. Normothermic machine perfusion (NMP) can be used to deliver therapies and may help in assessing the effects of IRI and immunity. This study investigated the effects of AAT on IRI and inflammation in pig kidneys when administered during preservation, followed by normothermic reperfusion (NR) with autologous whole blood, as a surrogate for transplant. Two different models were used to deliver AAT or placebo to paired slaughterhouse pig kidneys: Model 1: 7-h static cold storage (SCS) + 3-h NR (n = 5 pairs), where either AAT (10 mg/ml) or placebo was delivered in the flush following retrieval; Model 2: 4-h SCS + 3-h NMP + 3-h NR (n = 5 pairs), where either AAT or placebo was delivered during NMP. Injury markers and cytokines levels were analysed in the perfusate, and heat shock protein 70 KDa (HSP-70) was analysed in biopsies. AAT delivered to kidneys showed no adverse effects on perfusion parameters. HSP-70 fold changes were significantly lower in the AAT group during NMP (P < 0.01, paired t-test) but not during NR. Interleukin-1 receptor antagonist (IL-1ra) fold changes were significantly higher in the AAT group during NR model 1 (p < 0.05, two-way ANOVA). In contrast to the AAT group, significant upregulation of interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) between t = 90 min and t = 180 min and interleukin-8 (IL-8) between baseline and t = 90 min was observed in the control group in NR model 2 (p < 0.05, Tukey's multiple comparison test). However, overall inflammatory cytokines and injury markers showed similar levels between groups. Delivery of AAT to pig kidneys was safe without any detrimental effects. NMP and NR provided excellent methods for comparison of inflammation and immune activation in the delivery of a novel therapy.

Epstein-Barr Virus-Negative Diffuse Large B-Cell Post-transplant Lymphoma in an Epstein-Barr Virus-Positive Recipient

Post-transplant lymphoproliferative disease (PTLD) can arise as a complication after solid organ transplantation. Epstein-Barr virus (EBV) infection is a known risk factor and is known to drive disease manifestation. PTLD can occur in EBV-negative recipients and with EBV-negative donor organs, however, EBV-negative PTLD pathogenesis is unknown. Here, we present PTLD presenting as intussusception in a patient with a historic simultaneous pancreas-kidney transplant (SPK). This case study presents the first documented case of EBV-negative post-transplant lymphoproliferative disease in an EBV-seropositive SPK recipient from an EBV-positive donor. Here we describe the diagnosis and management of this patient, discuss the differences between EBV positive and negative driven post-transplant lymphoproliferative disease, and highlight areas of research opportunity in the latter.

Development of ex situ normothermic reperfusion as an innovative method to assess pancreases after preservation

Static cold storage (SCS) is the standard method for pancreas preservation prior to transplantation; however, it does not permit organ assessment. Normothermic reperfusion (NR) is utilized clinically for other organs to assess viability. Our aim was to develop NR using normothermic machine perfusion technique to simulate reperfusion at the time of transplantation, enabling evaluation of oxygenated hypothermic machine perfusion (HMPO2) as a newer strategy to optimize pancreas preservation. 13 porcine pancreases procured after circulatory death were divided into 3 groups: 4 pancreases preserved using SCS, and 2 groups preserved by HMPO2 (n = 4 and n = 5, differing by type of preservation solution). Duration of perfusion or cold storage was 6 hours before the 1-hour assessment using NR. Outcome measures were perfusion characteristics, biochemistry and change in tissue water mass as oedema assessment. During NR, the HMPO2 groups demonstrated better perfusion characteristics, normal macroscopic appearances, decreased water mass and one HMPO2 group demonstrated a response to glucose stimulation. Conversely, the SCS group showed an increased water mass and developed early macroscopic appearances of oedema, interstitial haemorrhage and minimal portal outflow. This study suggests that ex situ assessment of pancreases by NR is promising, and that HMPO2 may be better than SCS.

Outcome measures in solid organ donor management research: a systematic review

AIM

We systematically reviewed published outcome measures across randomised controlled trials (RCTs) of donor management interventions.

METHODS

The systematic review was conducted in accordance with recommendations by the Cochrane Handbook and Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We searched MEDLINE, Embase, CENTRAL, Web of Science, and trial databases from 1980 to February 2021 for RCTs of donor management interventions.

RESULTS

Twenty-two RCTs (n=3432 donors) were included in our analysis. Fourteen RCTs (63.6%) reported a primary outcome relating to a single organ only. Eight RCTs primarily focused on aspects of donor optimisation in critical care. Thyroid hormones and methylprednisolone were the most commonly evaluated interventions (five and four studies, respectively). Only two studies, focusing on single organs (e.g. kidney), evaluated outcomes relating to other organs. The majority of studies evaluated physiological or biomarker-related outcomes. No study evaluated recipient health-related quality of life. Only one study sought consent from potential organ recipients.

CONCLUSIONS

The majority of RCTs evaluating donor management interventions only assessed single-organ outcomes or effects on donor stability in critical care. There is a need for an evaluation of patient-centred recipient outcomes and standardisation and reporting of outcome measures for future donor management RCTs.

Virological Characterization of Critically Ill Patients With COVID-19 in the United Kingdom: Interactions of Viral Load, Antibody Status, and B.1.1.7 Infection

BACKGROUND

Convalescent plasma containing neutralizing antibody to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is under investigation for coronavirus disease 2019 (COVID-19) treatment. We report diverse virological characteristics of UK intensive care patients enrolled in the Immunoglobulin Domain of the REMAP-CAP randomized controlled trial that potentially influence treatment outcomes.

METHODS

SARS-CoV-2 RNA in nasopharyngeal swabs collected pretreatment was quantified by PCR. Antibody status was determined by spike-protein ELISA. B.1.1.7 was differentiated from other SARS-CoV-2 strains using allele-specific probes or restriction site polymorphism (SfcI) targeting D1118H.

RESULTS

Of 1274 subjects, 90% were PCR positive with viral loads 118-1.7 × 1011IU/mL. Median viral loads were 40-fold higher in those IgG seronegative (n = 354; 28%) compared to seropositives (n = 939; 72%). Frequencies of B.1.1.7 increased from <1% in November 2020 to 82% of subjects in January 2021. Seronegative individuals with wild-type SARS-CoV-2 had significantly higher viral loads than seropositives (medians 5.8 × 106 and 2.0 × 105 IU/mL, respectively; P = 2 × 10-15).

CONCLUSIONS

High viral loads in seropositive B.1.1.7-infected subjects and resistance to seroconversion indicate less effective clearance by innate and adaptive immune responses. SARS-CoV-2 strain, viral loads, and antibody status define subgroups for analysis of treatment efficacy.

Comparability of six different immunoassays measuring SARS-CoV-2 antibodies with neutralizing antibody levels in convalescent plasma: From utility to prediction

BACKGROUND

Convalescent plasma (CP) therapy for coronavirus disease (COVID-19) provides virus-neutralizing antibodies that may ameliorate the outcome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The effectiveness of CP likely depends on its antiviral neutralizing potency and is determined using in vitro neutralizing antibody assays.

STUDY DESIGN AND METHODS

We evaluated abilities of three immunoassays for anti-spike antibodies (EUROimmun, Ortho, Roche), a pseudotype-based neutralization assay, and two assays that quantify ACE2 binding of spike protein (GenScript and hemagglutination test [HAT]-based assay) to predict neutralizing antibody titers in 113 CP donations. Assay outputs were analyzed through linear regression and calculation of sensitivities and specificities by receiver operator characteristic (ROC) analysis.

RESULTS

Median values of plasma samples containing neutralizing antibodies produced conversion factors for assay unitage of ×6.5 (pseudotype), ×19 (GenScript), ×3.4 (HAT assay), ×0.08 (EUROimmun), ×1.64 (Roche), and ×0.10 (Ortho). All selected assays were sufficient in identifying the high titer donations based on ROC analysis; area over curve ranged from 91.7% for HAT and GenScript assay to 95.6% for pseudotype assay. However, their ability to predict the actual neutralizing antibody levels varied substantially as shown by linear regression correlation values (from 0.27 for Ortho to 0.61 for pseudotype assay).

DISCUSSION

Overall, the study data demonstrate that all selected assays were effective in identifying donations with high neutralizing antibody levels and are potentially suitable as surrogate assays for donation selection for CP therapy.

Effect of Utilizing More Than 20-Year Older Deceased Donor Kidneys for Young Recipients: An Analysis of the UK Registry

OBJECTIVES

Despite the wider acceptance of expanded criteria kidneys and the advances in immunosuppression, clinicians remain sceptical when it comes to accepting kidneys from significantly older donors, especially for the young adult recipient population (age ≤40 years).

MATERIALS AND METHODS

We utilized prospectively maintained data from the United Kingdom Registry and analyzed the deceased donor renal transplant outcomes for 2 cohorts: (1) young recipients who received either a younger kidney or a kidney from a donor who was less than 20 years older (group <20; n = 2072) and (2) young recipients who received a kidney from donors who were 20 or more years older (group ≥20, n = 764). We used life tables for survival and performed Cox regression analysis to identify significant variables.

RESULTS

Median follow-up was 2918 days. The univariate analysis for graft loss showed the strongest predictors to be donor age, recipient age, recipient ethnicity, and delayed graft function, which retained their significance in the multivariate model. Graft survival rates were 94% versus 90% at 1 year, 86% versus 75% at 5 years, and 75% versus 63% at 10 years for group <20 versus group ≥20, respectively. Respective patient survival rates were comparable for both cohorts: 99% versus 98% at 1 year, 97% versus 96% at 5 years, and 91% versus 91% at 10 years.

CONCLUSIONS

Our analysis showed that allografts from ≥20-year-older deceased donors are beneficial and should be considered for transplant in younger recipients. Allograft survival may be worse compared with survival with younger allografts; however, young recipients do potentially better and survive longer compared with remaining on dialysis.

Multicenter validation of the liver graft assessment following transplantation (L-GrAFT) score for assessment of early allograft dysfunction

BACKGROUND & AIMS

Early allograft dysfunction (EAD) following liver transplantation (LT) negatively impacts graft and patient outcomes. Previously we reported that the liver graft assessment following transplantation (L-GrAFT₇) risk score was superior to binary EAD or the model for early allograft function (MEAF) score for estimating 3-month graft failure-free survival in a single-center derivation cohort. Herein, we sought to externally validate L-GrAFT₇, and compare its prognostic performance to EAD and MEAF.

METHODS

Accuracies of L-GrAFT₇, EAD, and MEAF were compared in a 3-center US validation cohort (n = 3,201), and a Consortium for Organ Preservation in Europe (COPE) normothermic machine perfusion (NMP) trial cohort (n = 222); characteristics were compared to assess generalizability.

RESULTS

Compared to the derivation cohort, patients in the validation and NMP trial cohort had lower recipient median MELD scores; were less likely to require pretransplant hospitalization, renal replacement therapy or mechanical ventilation; and had superior 1-year overall (90% and 95% vs. 84%) and graft failure-free (88% and 93% vs. 81%) survival, with a lower incidence of 3-month graft failure (7.4% and 4.0% vs. 11.1%; p <0.001 for all comparisons). Despite significant differences in cohort characteristics, L-GrAFT₇ maintained an excellent validation AUROC of 0.78, significantly superior to binary EAD (AUROC 0.68, p = 0.001) and MEAF scores (AUROC 0.72, p <0.001). In post hoc analysis of the COPE NMP trial, the highest tertile of L-GrAFT₇ was significantly associated with time to liver allograft (hazard ratio [HR] 2.17, p = 0.016), Clavien ≥IIIB (HR 2.60, p = 0.034) and ≥IVa (HR 4.99, p = 0.011) complications; post-LT length of hospitalization (p = 0.002); and renal replacement therapy (odds ratio 3.62, p = 0.016).

CONCLUSIONS

We have validated the L-GrAFT₇ risk score as a generalizable, highly accurate, individualized risk assessment of 3-month liver allograft failure that is superior to existing scores. L-GrAFT₇ may standardize grading of early hepatic allograft function and serve as a clinical endpoint in translational studies (www.lgraft.com).

LAY SUMMARY

Early allograft dysfunction negatively affects outcomes following liver transplantation. In independent multicenter US and European cohorts totaling 3,423 patients undergoing liver transplantation, the liver graft assessment following transplantation (L-GrAFT) risk score is validated as a superior measure of early allograft function that accurately discriminates 3-month graft failure-free survival and post-liver transplantation complications.

A haemagglutination test for rapid detection of antibodies to SARS-CoV-2

Serological detection of antibodies to SARS-CoV-2 is essential for establishing rates of seroconversion in populations, and for seeking evidence for a level of antibody that may be protective against COVID-19 disease. Several high-performance commercial tests have been described, but these require centralised laboratory facilities that are comparatively expensive, and therefore not available universally. Red cell agglutination tests do not require special equipment, are read by eye, have short development times, low cost and can be applied at the Point of Care. Here we describe a quantitative Haemagglutination test (HAT) for the detection of antibodies to the receptor binding domain of the SARS-CoV-2 spike protein. The HAT has a sensitivity of 90% and specificity of 99% for detection of antibodies after a PCR diagnosed infection. We will supply aliquots of the test reagent sufficient for ten thousand test wells free of charge to qualified research groups anywhere in the world.

Reparative effect of mesenchymal stromal cells on endothelial cells after hypoxic and inflammatory injury

Background

The renal endothelium is a prime target for ischemia-reperfusion injury (IRI) during donation and transplantation procedures. Mesenchymal stromal cells (MSC) have been shown to ameliorate kidney function after IRI. However, whether this involves repair of the endothelium is not clear. Therefore, our objective is to study potential regenerative effects of MSC on injured endothelial cells and to identify the molecular mechanisms involved.

Methods

Human umbilical vein endothelial cells (HUVEC) were submitted to hypoxia and reoxygenation and TNF-α treatment. To determine whether physical interaction or soluble factors released by MSC were responsible for the potential regenerative effects of MSC on endothelial cells, dose-response experiments were performed in co-culture and transwell conditions and with secretome-deficient MSC.

Results

MSC showed increased migration and adhesion to injured HUVEC, mediated by CD29 and CD44 on the MSC membrane. MSC decreased membrane injury marker expression, oxidative stress levels, and monolayer permeability of injured HUVEC, which was observed only when allowing both physical and paracrine interaction between MSC and HUVEC. Furthermore, viable MSC in direct contact with injured HUVEC improved wound healing capacity by 45% and completely restored their angiogenic capacity. In addition, MSC exhibited an increased ability to migrate through an injured HUVEC monolayer compared to non-injured HUVEC in vitro.

Conclusions

These results show that MSC have regenerative effects on injured HUVEC via a mechanism which requires both physical and paracrine interaction. The identification of specific effector molecules involved in MSC-HUVEC interaction will allow targeted modification of MSC to apply and enhance the therapeutic effects of MSC in IRI.

Outcomes of Patients Suspended From the National Kidney Transplant Waiting List in the United Kingdom Between 2000 and 2010

BACKGROUND

In the United Kingdom, 1 in 3 patients on the National Kidney Transplant Waiting List (NKTWL) is suspended from the list at least once during their wait. The mortality of this large cohort of patients remains underreported and poorly described.

METHODS

We linked patient records from the UK transplant registry to mortality data from the Office of National Statistics and evaluated the impact of a clinically induced suspension event by estimating hazard ratios (HRs) that compared mortality and graft survival between those who had experienced a suspension event and those who had not.

RESULTS

Between January 1, 2000, and December 31, 2010, 16.7% (2221/13 322) of all patients registered on the NKTWL were suspended. Forty-eight percent (588/1225) of those who were suspended and who were never transplanted died, most often from cardiothoracic causes. A suspension event was associated with increased mortality from the time of listing (adjusted HR [aHR], 1.79; 1.64-1.95) and from the time of transplantation (aHR, 1.20; 1.06-1.37; P = 0.005). Graft survival was also poorer in those who had been suspended (aHR, 1.13; 1.01-1.28; P = 0.04).

CONCLUSIONS

Patients suspended on the NKTWL have a significantly higher rate of mortality both on the waiting list and following transplantation. Earlier prioritization of patients at risk of experiencing a suspension event may improve their outcomes.

Development of a novel hybrid bioactive hydrogel for future clinical applications

Three-dimensional hydrogels are ideal for tissue engineering applications due to their structural integrity and similarity to native soft tissues; however, they can lack mechanical stability. Our objective was to develop a bioactive and mechanically stable hydrogel for clinical application. Auricular cartilage was decellularised using a combination of hypertonic and hypotonic solutions with and without enzymes to produce acellular tissue. Methacryloyl groups were crosslinked with alginate and PVA main chains via 2-aminoethylmathacrylate and the entire macromonomer further crosslinked with the acellular tissue. The resultant hydrogels were characterised for its physicochemical properties (using NMR), in vitro degradation (via GPC analysis), mechanical stability (compression tests) and in vitro biocompatibility (co-culture with bone marrow-derived mesenchymal stem cells). Following decellularisation, the cartilage tissue showed to be acellular at a significant level (DNA content 25.33 ng/mg vs. 351.46 ng/mg control tissue), with good structural and molecular integrity of the retained extra cellular matrix (s-GAG= 0.19 μg/mg vs. 0.65 μg/mg ±0.001 control tissue). Proteomic analysis showed that collagen subtypes and proteoglycans were retained, and SEM and TEM showed preserved matrix ultra-structure. The hybrid hydrogel was successfully cross-linked with biological and polymer components, and it was stable for 30 days in simulated body fluid (poly dispersal index for alginate with tissue was stable at 1.08 and for PVA with tissue was stable at 1.16). It was also mechanically stable (Young's modulus of 0.46 ± 0.31 KPa) and biocompatible, as it was able to support the development of a multi-cellular feature with active cellular proliferation in vitro. We have shown that it is possible to successfully combine biological tissue with both a synthetic and natural polymer and create a hybrid bioactive hydrogel for clinical application.

Infusing Mesenchymal Stromal Cells into Porcine Kidneys during Normothermic Machine Perfusion: Intact MSCs Can Be Traced and Localised to Glomeruli

Normothermic machine perfusion (NMP) of kidneys offers the opportunity to perform active interventions, such as the addition of mesenchymal stromal cells (MSCs), to an isolated organ prior to transplantation. The purpose of this study was to determine whether administering MSCs to kidneys during NMP is feasible, what the effect of NMP is on MSCs and whether intact MSCs are retained in the kidney and to which structures they home. Viable porcine kidneys were obtained from a slaughterhouse. Kidneys were machine perfused during 7 h at 37 °C. After 1 h of perfusion either 0, 10⁵, 10⁶ or 10⁷ human adipose tissue derived MSCs were added. Additional ex vivo perfusions were conducted with fluorescent pre-labelled bone-marrow derived MSCs to assess localisation and survival of MSCs during NMP. After NMP, intact MSCs were detected by immunohistochemistry in the lumen of glomerular capillaries, but only in the 10⁷ MSC group. The experiments with fluorescent pre-labelled MSCs showed that only a minority of glomeruli were positive for infused MSCs and most of these glomeruli contained multiple MSCs. Flow cytometry showed that the number of infused MSCs in the perfusion circuit steeply declined during NMP to approximately 10%. In conclusion, the number of circulating MSCs in the perfusate decreases rapidly in time and after NMP only a small portion of the MSCs are intact and these appear to be clustered in a minority of glomeruli.

Family overrule of registered refusal to donate organs

It is well known that families frequently overrule the wishes of dying patients who had previously expressed a wish to donate their organs. Various strategies have been suggested to reduce the frequency of these 'family overrules'. However, the possibility of families overruling a patient's registered decision not to donate has not been discussed in the medical literature, although it is legally possible in some countries. In this article, we provide an ethical analysis of family overrule of a relative's refusal to donate, using the different jurisdictions of the UK, Switzerland, Germany and the Netherlands to provide some context. Despite some asymmetries between overruling consent and overruling refusal, there are some cases in which donation should proceed despite a recorded refusal to do so.

Decoding cold ischaemia time impact on kidney graft: the kinetics of the unfolded protein response pathways

The relationship between cold ischaemia time (CIT) and adverse outcome is now acknowledged. However, the underlying mechanisms remain to be defined, which slows the development of adapted therapeutics and diagnostics. We explored the impact of CIT in both preclinical and in vitro models of preservation. We determined that the endoplasmic reticulum (ER) and its stress response (unfolded protein response, UPR) were regulated in close association with CIT; the eIF2α-ATF4 pathway was inhibited early (1-8 h) at the detriment of cell survival, while the ATF6 pathway was activated late (12-24 h) and associated with cell death. The IRE1α-XBP1 branch was activated at reperfusion only if CIT extended beyond 8 h, and had a dual role on cell fate - deleterious through IRE1's RNase activity and beneficial through IRE1α other roles. Finally, the pro-apoptotic factor CHOP was a common target of both ATF6 and IRE1α pathways and was associated with elongated CIT and increased cell death. Microarray analysis of human transplanted kidney confirmed that UPR markers were regulated by CIT and that CHOP was associated with adverse outcome. We show that UPR could be a critical pathway explaining the relationship between CIT and graft outcome, highlighting the potential for UPR-based therapeutics and diagnostics to improve transplantation.

Conscientious objection to deceased organ donation by healthcare professionals

In this article, we analyse the potential benefits and disadvantages of permitting healthcare professionals to invoke conscientious objection to deceased organ donation. There is some evidence that permitting doctors and nurses to register objections can ultimately lead to attitudinal change and acceptance of organ donation. However, while there may be grounds for conscientious objection in other cases such as abortion and euthanasia, the life-saving nature of donation and transplantation renders objection in this context more difficult to justify. In general, dialogue between healthcare professionals is a more appropriate solution, and any objections must be justified with a strong rationale in hospitals where such policies are put in place.

New classification of donation after circulatory death donors definitions and terminology

In the face of a crisis in organ donation, the transplant community are increasingly utilizing donation after circulatory death (DCD) donors. Over the last 10 years, with the increasing usage of DCD donors, we have seen the introduction in a number of new terms and definitions. We report the results of the 6th International Conference in Organ Donation held in Paris in 2013 and report a consensus agreement of an established expert European Working Group on the definitions and terminology regarding DCD donation, including refinement of the Maastricht definitions. This document forms part of a special series where recommendations are presented for uncontrolled and controlled DCD donation and organ specific guidelines for kidney, pancreas, liver and lung transplantation. An expert panel formed a consensus on definitions and terms aiming to establish consistent usage of terms in DCD donation.

Gradual Rewarming with Gradual Increase in Pressure during Machine Perfusion after Cold Static Preservation Reduces Kidney Ischemia Reperfusion Injury

In this study we evaluated whether gradual rewarming after the period of cold ischemia would improve organ quality in an Isolated Perfused Kidney Model. Left rat kidneys were statically cold stored in University of Wisconsin solution for 24 hours at 4°C. After cold storage kidneys were rewarmed in one of three ways: perfusion at body temperature (38°C), or rewarmed gradually from 10°C to 38°C with stabilization at 10°C for 30 min and rewarmed gradually from 10°C to 38°C with stabilization at 25°C for 30 min. In the gradual rewarming groups the pressure was increased stepwise to 40 mmHg at 10°C and 70 mmHg at 25°C to counteract for vasodilatation leading to low perfusate flows. Renal function parameters and injury biomarkers were measured in perfusate and urine samples. Increases in injury biomarkers such as aspartate transaminase and lactate dehydrogenase in the perfusate were lower in the gradual rewarming groups versus the control group. Sodium re-absorption was improved in the gradual rewarming groups and reached significance in the 25°C group after ninety minutes of perfusion. HSP-70, ICAM-1, VCAM-1 mRNA expressions were decreased in the 10°C and 25°C groups. Based on the data kidneys that underwent gradual rewarming suffered less renal parenchymal, tubular injury and showed better endothelial preservation. Renal function improved in the gradual rewarming groups versus the control group.

Renal function and cardiovascular outcomes after living donor nephrectomy in the UK: quality and safety revisited

OBJECTIVE

To determine renal function and cardiovascular outcomes after living donor nephrectomy (LDN). Living donor kidney transplantation has become established as the treatment of choice for end-stage renal failure. Benefits to the recipient have to be balanced against perioperative and long-term health risks to the donor.

SUBJECTS/PATIENTS AND METHODS

The UK Transplant Registry (UKTR) was used to identify 4586 living donors who had donated a kidney for transplantation in the UK between 2001 and 2008. This study was conducted with the consent and support of the NHS Blood and Transplant (NHSBT) Kidney and Pancreas Research Group.

RESULTS

The mean glomerular filtration rate (GFR) fell from 103 mL/min/1.73 m(2) before LDN to 58 mL/min/1.73 m(2) 1 year after LDN. At 1 year after LDN 60% of donors had a GFR of <60 mL/min/1.73 m(2). A GFR of <60 mL/min/1.73 m(2) after LDN was associated with older age, females, lower GFR before LDN, White ethnicity, earlier LDN period, unrelated donor type and body mass index of >25 kg/m(2). Over a 2-year period after LDN there was an overall mortality rate of 0.39%, cardiovascular death in one patient (mortality rate of 0.02%) and a major cardiovascular event rate of 0.44%.

CONCLUSION

In this study we show that mild renal dysfunction is common after LDN; however, due to the short duration of follow-up we are unable to comment on whether this subsequently leads to an increased risk of developing of cardiovascular disease.

Early learning effect of residents for laparoscopic sigmoid resection

OBJECTIVE

To evaluate the effect of learning the laparoscopic sigmoid resection procedure on resident surgeons; establish a minimum number of cases before a resident surgeon could be expected to achieve proficiency with the procedure; and examine if an analysis could be used to measure and support the clinical evaluation of the surgeon's competence with the procedure.

DESIGN

Retrospective analysis of data which was prospective entered in the database.

PARTICIPANTS

From 2003 to 2007 all patients who underwent a laparoscopic sigmoid resection carried out by senior residents, who completed the procedure as the primary surgeon proctored by an experienced surgeon, were included in the study. A cumulative sum control chart (CUSUM) analysis was used evaluate performance. The procedure was defined as a failure if major intra-operative complications occurred such as intra abdominal organ injury, bleeding, or anastomotic leakage; if an inadequate number of lymph nodes (<12 nodes) were removed; or if conversion to an open surgical procedure was required.

RESULTS

Thirteen residents performed 169 laparoscopic sigmoid resections in the period evaluated. A significant majority of the resident surgeons were able to consistently perform the procedure without failure after 11 cases and determined to be competent. One resident was not determined to be competent and the CUSUM score supported these findings.

CONCLUSIONS

We concluded that at least 11 cases are required for most residents to obtain necessary competence with the laparoscopic sigmoid resection procedure. Evaluation with the CUSUM analysis can be used to measure and support the clinical evaluation of the resident surgeon's competence with the procedure.

Effect of proctoring on implementation and results of elective laparoscopic colon surgery

PURPOSE

A steep learning curve exists for surgeons to become skilled in laparoscopic colon resection. Our institute offers a proctored training programme. The purpose of this descriptive study was to evaluate whether the course resulted in adoption of laparoscopic colorectal surgery into clinical practice, explore post-course practice patterns and analyse the outcome of surgical performance.

METHODS

Between 2003 and 2008, 26 surgeons were trained by our institute. The course consisted of 24 elective laparoscopic resections under direct supervision. A questionnaire and a prospective post-course web-based registration were used to analyse the effect of the training and the outcome of surgical performance.

RESULTS

The response rate of the questionnaire was 85%. The majority had not performed any laparoscopic colon resections before attending the course. All 24 respondents successfully implemented laparoscopy into daily practice. After the course, 70% of all sigmoid resections were performed laparoscopically in contrast with 0% of all transverse colon resections. The results of the trainees after following the course are equal to results of other studies.

CONCLUSIONS

A proctored training programme, consisting of 24 supervised cases, is safe and feasible. For adequate monitoring, participating in a post-course registry should be obligatory.

The critical pathway for deceased donation: reportable uniformity in the approach to deceased donation

The critical pathway of deceased donation provides a systematic approach to the organ donation process, considering both donation after cardiac death than donation after brain death. The pathway provides a tool for assessing the potential of deceased donation and for the prospective identification and referral of possible deceased donors.

Modulation of brain dead induced inflammation by vagus nerve stimulation

Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip-analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFalpha concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFalpha concentrations and resulted in down-regulation of a multiplicity of pro-inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E-selectin, IL1beta and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFalpha through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

Modulation of brain dead induced inflammation by vagus nerve stimulation

Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip-analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFalpha concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFalpha concentrations and resulted in down-regulation of a multiplicity of pro-inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E-selectin, IL1beta and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFalpha through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

Elective laparoscopic recto-sigmoid resection for diverticular disease is suitable as a training operation

PURPOSE

Some authors state that elective laparoscopic recto-sigmoid resection is more difficult for diverticular disease as compared with malignancy. For this reason, starting laparoscopic surgeons might avoid diverticulitis, making the implementation phase unnecessary long. The aim of this study was to determine whether laparoscopic resection for diverticular disease should be included during the implementation phase.

METHODS

All consecutive patients who underwent an elective laparoscopic recto-sigmoid resection in our hospital for diverticulitis or cancer from 2003 to 2007 were analysed.

RESULTS

A total of 256 consecutive patients were included in this prospective cohort study. One hundred and fifty-one patients were operated on for diverticulitis and 105 for cancer. There was no significant difference in operation time (168 vs. 172 min), blood loss (189 vs. 208 ml), conversion rates (9.9% vs. 11.4%), hospital stay (8 vs. 8 days), total number of peroperative (2.3% vs. 1.6%) or postoperative complications (21.9% vs. 26.9%). The occurrence of anastomotic leakages was associated with higher American Society of Anesthesiologists (ASA) classification, which differed between the groups (86.8% vs. 64.8% ASA I-II, p < 0.001).

CONCLUSION

Since there are no differences in operation time, blood loss, conversion rate and total complications, there is no need to avoid laparoscopic recto-sigmoid resection for diverticular disease early in the learning curve.

Hypothermia-Induced Loss of Endothelial Barrier Function Is Restored after Dopamine Pretreatment: Role of p42/p44 Activation

BACKGROUND

Donor dopamine usage is associated with improved immediate graft function after renal transplantation. Although prolonged cold preservation results in an increased vascular permeability, the present study was conducted to examine in vitro and in vivo if dopamine pretreatment influences endothelial barrier function under such conditions.

METHODS

To assess cold preservation injury in vitro and in vivo, cultured human umbilical vein endothelial cells (HUVEC) and Lewis donor rats were pretreated with dopamine or isotonic saline prior to cold storage. Injury was determined by lactate dehydrogenase (LDH) release, histology, and functional analysis.

RESULTS

In vitro cold storage resulted in intercellular gap formation in both untreated and dopamine pretreated HUVEC. In the latter monolayer integrity was completely restored upon rewarming and paracellular transport of fluorescein isothiocyanate-dextran was significantly reduced. In dopamine treated HUVEC, intercellular gap formation was independent of cell death and was associated with redistribution of junctional proteins and condensation of cytoskeleton proteins. In untreated HUVEC proteolysis and cell death were clearly evident after hypothermia. Closing of intercellular gaps was dependent on p42/p44 activation. Regeneration of adenosine triphosphate was only observed in dopamine pretreated cells. Only in dopamine treated Lewis renal allografts subjected to cold storage, activation of p42/p44 occurred upon rewarming. These grafts had a better renal function and displayed less inflammatory cells five days after transplantation.

CONCLUSION

Our study demonstrates beneficial effects of dopamine treatment on cold storage induced endothelial barrier disturbances. This may contribute to the positive effects of catecholamines on immediate graft function of renal allografts in men.