Antecedent Cardiac Arrest Status of Donation After Circulatory Determination of Death (DCDD) Kidney Donors and the Risk of Delayed Graft Function After Kidney Transplantation: A Cohort Study.

BACKGROUND: The number of donors from donation after circulatory determination of death (DCDD) has increased by at least 4-fold over the past decade. This study evaluated the association between the antecedent cardiac arrest status of controlled DCDD donors and the risk of delayed graft function (DGF). METHODS: Using data from the Australia and New Zealand Dialysis and Transplant, the associations between antecedent cardiac arrest status of DCDD donors before withdrawal of cardiorespiratory support, DGF, posttransplant estimated glomerular filtration rate (eGFR), and allograft loss were examined using adjusted logistic, linear mixed modeling, and cox regression, respectively. Among donors who experienced cardiac arrest, we evaluated the association between duration and unwitnessed status of arrest and DGF. RESULTS: A total of 1173 kidney transplant recipients received DCDD kidneys from 646 donors in Australia between 2014 and 2019. Of these, 335 DCDD had antecedent cardiac arrest. Compared with recipients of kidneys from donors without antecedent cardiac arrest, the adjusted odds ratio (95% confidence interval) for DGF was 0.85 (0.65-1.11) among those with kidneys from donors with cardiac arrest. There was no association between antecedent cardiac arrest and posttransplant eGFR or allograft loss. The duration of cardiac arrest and unwitnessed status were not associated with DGF. CONCLUSIONS: This focused analysis in an Australian population showed that the allograft outcomes were similar whether DCDD donors had experienced a prior cardiac arrest, with no associations between duration or unwitnessed status of arrest and risk of DGF. This study thus provides important reassurance to transplant programs and the patients they counsel, to accept kidneys from donors through the DCDD pathway irrespective of a prior cardiac arrest.

Novel Perspectives in Chronic Kidney Disease-Specific Cardiovascular Disease.

Chronic kidney disease (CKD) affects > 10% of the global adult population and significantly increases the risk of cardiovascular disease (CVD), which remains the leading cause of death in this population. The development and progression of CVD-compared to the general population-is premature and accelerated, manifesting as coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. CKD and CV disease combine to cause multimorbid cardiorenal syndrome (CRS) due to contributions from shared risk factors, including systolic hypertension, diabetes mellitus, obesity, and dyslipidemia. Additional neurohormonal activation, innate immunity, and inflammation contribute to progressive cardiac and renal deterioration, reflecting the strong bidirectional interaction between these organ systems. A shared molecular pathophysiology-including inflammation, oxidative stress, senescence, and hemodynamic fluctuations characterise all types of CRS. This review highlights the evolving paradigm and recent advances in our understanding of the molecular biology of CRS, outlining the potential for disease-specific therapies and biomarker disease detection.

Long-term Kidney Transplant Survival Across the Globe.

BACKGROUND: The outcomes after kidney transplantation (KT), including access, wait time, and other issues around the globe, have been studied. However, issues do vary from one country to another. METHODS: We obtained data from several countries from North America, South America, Europe, Asia, and Australia, including the number of patients awaiting KT from 2015, transplant rate per million population (pmp), proportion of living donor and deceased donor (LD/DD) KT, and posttransplant survival. We also sought opinions on key difficulties faced by each of these countries with respect to KT and long-term survival. RESULTS: Variation in access to KT across the globe was noted. Countries with the highest rates of KT pmp included the United States (79%) and Spain (71%). A higher proportion of LD transplants was noted in Japan (93%), India (85%), Singapore (63%), and South Korea (63%). A higher proportion of DD KTs was noted in Spain (90%), Brazil (90%), France (85%), Italy (85%), Finland (85%), Australia-New Zealand (80%), and the United States (77%). The 5-y graft survival for LD was highest in South Korea (95%), Singapore (94%), Italy (93%), Finland (93%), and Japan (93%), whereas for DD, it was South Korea (93%), Italy (88%), Japan (86%), and Singapore (86%). The common issues surrounding KTs are access and a limited number of LDs and DDs. Key issues identified for long-term survival were increasing age of donors and recipients, higher recipient comorbidity, and posttransplant events, such as alloimmune injury to the kidney, infection, cancer, and suboptimal adherence to therapy. CONCLUSIONS: A unified approach is necessary to improve issues surrounding KT as the demand continues to increase.

A study protocol for live and deceased donor uterus transplantation as a treatment for women with uterine factor infertility.

AIM: Uterus transplantation (UTx) is an emerging treatment option for women with uterine factor infertility (UFI) or the absence of a functional uterus. This is the study protocol for the first human UTx clinical trial in Australia. MATERIALS AND METHODS: This protocol outlines the approved training program used to plan, diagnose, screen, and treat patients who may be eligible for UTx using living and deceased donors. This multi-site clinical research study includes three tertiary hospital sites within New South Wales (NSW), Australia - Prince of Wales, Royal Hospital for Women and Westmead Hospitals. Our UTx protocol is based on that used by our collaborative partner, the inaugural UTx team in Gothenburg, Sweden. The Swedish UTx team provides ongoing preceptorship for the Australian UTx team. Ethics approval for six UTx procedures using living or deceased donors (Western Sydney Local Health District Human Research Ethics Committee: 2019/ETH138038) was granted in 2020. RESULTS: Results from surgeries and live births will be published. Data will be prospectively entered into the registry of the International Society of Uterus Transplantation (ISUTx), a sub-section of The Transplantation Society (TTS). TRIAL ID: ACTRN12622000917730. DISCUSSION: A multidisciplinary research team has been formed between three tertiary hospitals in Sydney - The Royal Hospital for Women, Prince of Wales and Westmead Hospitals; and with the Swedish UTx, University of Gothenburg. The Swedish team pioneered animal and human UTx studies since 1998, including publishing the first live birth after UTx. (1) This Australian trial commenced in January 2023. CONCLUSION: Uterus transplantation gives women with UFI the opportunity to be gestational and genetic mothers. It is a complex procedure for both the donor and recipient, with medical and surgical risks. An extensive multidisciplinary approach is required to optimise patient safety and graft outcomes. This protocol outlines our Australian UTx team strategy for screening, recruitment, surgical approach, and clinical management of UTx recipients and donors.

Intragraft memory-like CD127hiCD4+Foxp3+ Tregs maintain transplant tolerance.

CD4+Foxp3+ regulatory T cells (Tregs) play an essential role in suppressing transplant rejection, but their role within the graft and heterogeneity in tolerance are poorly understood. Here, we compared phenotypic and transcriptomic characteristics of Treg populations within lymphoid organs and grafts in an islet xenotransplant model of tolerance. We showed Tregs were essential for tolerance induction and maintenance. Tregs demonstrated heterogeneity within the graft and lymphoid organs of tolerant mice. A subpopulation of CD127hi Tregs with memory features were found in lymphoid organs, presented in high proportions within long-surviving islet grafts, and had a transcriptomic and phenotypic profile similar to tissue Tregs. Importantly, these memory-like CD127hi Tregs were better able to prevent rejection by effector T cells, after adoptive transfer into secondary Rag-/- hosts, than naive Tregs or unselected Tregs from tolerant mice. Administration of IL-7 to the CD127hi Treg subset was associated with a strong activation of phosphorylation of STAT5. We proposed that memory-like CD127hi Tregs developed within the draining lymph node and underwent further genetic reprogramming within the graft toward a phenotype that had shared characteristics with other tissue or tumor Tregs. These findings suggested that engineering Tregs with these characteristics either in vivo or for adoptive transfer could enhance transplant tolerance.

Blood-Based Transcriptomic Biomarkers Are Predictive of Neurodegeneration Rather Than Alzheimer's Disease.

Alzheimer's disease (AD) is a growing global health crisis affecting millions and incurring substantial economic costs. However, clinical diagnosis remains challenging, with misdiagnoses and underdiagnoses being prevalent. There is an increased focus on putative, blood-based biomarkers that may be useful for the diagnosis as well as early detection of AD. In the present study, we used an unbiased combination of machine learning and functional network analyses to identify blood gene biomarker candidates in AD. Using supervised machine learning, we also determined whether these candidates were indeed unique to AD or whether they were indicative of other neurodegenerative diseases, such as Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Our analyses showed that genes involved in spliceosome assembly, RNA binding, transcription, protein synthesis, mitoribosomes, and NADH dehydrogenase were the best-performing genes for identifying AD patients relative to cognitively healthy controls. This transcriptomic signature, however, was not unique to AD, and subsequent machine learning showed that this signature could also predict PD and ALS relative to controls without neurodegenerative disease. Combined, our results suggest that mRNA from whole blood can indeed be used to screen for patients with neurodegeneration but may be less effective in diagnosing the specific neurodegenerative disease.

A metabolic role for CD47 in pancreatic ß cell insulin secretion and islet transplant outcomes.

Diabetes is a global public health burden and is characterized clinically by relative or absolute insulin deficiency. Therapeutic agents that stimulate insulin secretion and improve insulin sensitivity are in high demand as treatment options. CD47 is a cell surface glycoprotein implicated in multiple cellular functions including recognition of self, angiogenesis, and nitric oxide signaling; however, its role in the regulation of insulin secretion remains unknown. Here, we demonstrate that CD47 receptor signaling inhibits insulin release from human as well as mouse pancreatic ß cells and that it can be pharmacologically exploited to boost insulin secretion in both models. CD47 depletion stimulated insulin granule exocytosis via activation of the Rho GTPase Cdc42 in ß cells and improved glucose clearance and insulin sensitivity in vivo. CD47 blockade enhanced syngeneic islet transplantation efficiency and expedited the return to euglycemia in streptozotocin-induced diabetic mice. Further, anti-CD47 antibody treatment delayed the onset of diabetes in nonobese diabetic (NOD) mice and protected them from overt diabetes. Our findings identify CD47 as a regulator of insulin secretion, and its manipulation in ß cells offers a therapeutic opportunity for diabetes and islet transplantation by correcting insulin deficiency.

Disease-modifying interactions between chronic kidney disease and osteoarthritis: a new comorbid mouse model.

OBJECTIVE: The prevalence of comorbid chronic kidney disease (CKD) and osteoarthritis (OA) is increasing globally. While sharing common risk factors, the mechanism and consequences of concurrent CKD-OA are unclear. The aims of the study were to develop a preclinical comorbid model, and to investigate the disease-modifying interactions. METHODS: Seventy (70) male 8-10 week-old C57BL/6 mice were subjected to 5/6 nephrectomy (5/6Nx)±destabilisation of medial meniscus (DMM) or sham surgery. OA pathology and CKD were assessed 12 weeks postinduction by blinded histology scoring, micro-CT, immunohistochemistry for osteoclast and matrix metalloproteinase (MMP)-13 activity, and serum analysis of bone metabolic markers. RESULTS: The 5/6Nx model recapitulated characteristic features of CKD, with renal fibrosis and deranged serum alkaline phosphatase, calcium and phosphate. There was no histological evidence of cartilage pathology induced by 5/6Nx alone, however, synovial MMP-13 expression and subchondral bone osteoclastic activity were increased (p<0.05), with accompanying reductions (p<0.05) in subchondral trabecular bone, bone volume and mineral density. DMM significantly (p<0.05) increased tibiofemoral cartilage damage, subchondral bone sclerosis, marginal osteophytes and synovitis, in association with increased cartilage and synovial MMP-13. DMM alone induced (p<0.05) renal fibrosis, proteinuria and increased (p<0.05) 5/6Nx-induced serum urea. However, DMM in 5/6Nx-mice resulted in significantly reduced (p<0.05) cartilage pathology and marginal osteophyte development, in association with reduced subchondral bone volume and density, and inhibition of 5/6Nx-induced subchondral bone osteoclast activation. CONCLUSION: This study assessed a world-first preclinical comorbid CKD-OA model. Our findings demonstrate significant bidirectional disease-modifying interaction between CKD and OA.

Trajectories of systolic blood pressure decline in kidney transplant donors prior to circulatory death and delayed graft function.

Background: Kidneys donated after circulatory death suffer a period of functional warm ischaemia before death, which may lead to early ischaemic injury. Effects of haemodynamic trajectories during the agonal phase on delayed graft function (DGF) is unknown. We aimed to predict the risk of DGF using patterns of trajectories of systolic blood pressure (SBP) declines in Maastricht category 3 kidney donors. Methods: We conducted a cohort study of all kidney transplant recipients in Australia who received kidneys from donation after circulatory death donors, divided into a derivation cohort (transplants between 9 April 2014 and 2 January 2018 [462 donors]) and a validation cohort (transplants between 6 January 2018 and 24 December 2019 [324 donors]). Patterns of SBP decline using latent class models were evaluated against the odds of DGF using a two-stage linear mixed effects model. Results: In the derivation cohort, 462 donors were included in the latent class analyses and 379 donors in the mixed effects model. Of the 696 eligible transplant recipients, 380 (54.6%) experienced DGF. Ten different trajectories, with distinct patterns of SBP decline were identified. Compared with recipients from donors with the slowest decline in SBP after withdrawal of cardiorespiratory support, the adjusted odds ratio (aOR) for DGF was 5.5 [95% confidence interval (CI) 1.38-28.0] for recipients from donors with a steeper decline and lowest SBP [mean 49.5 mmHg (standard deviation 12.5)] at the time of withdrawal. For every 1 mmHg/min reduction in the rate of decline of SBP, the respective aORs for DGF were 0.95 (95% CI 0.91-0.99) and 0.98 (95% CI 0.93-1.0) in the random forest and least absolute shrinkage and selection operator models. In the validation cohort, the respective aORs were 0.95 (95% CI 0.91-1.0) and 0.99 (95% CI 0.94-1.0). Conclusion: Trajectories of SBP decline and their determinants are predictive of DGF. These results support a trajectory-based assessment of haemodynamic changes in donors after circulatory death during the agonal phase for donor suitability and post-transplant outcomes.

Deceased donor availability for uterus transplantation in Australia.

BACKGROUND: Uterus transplantation is an emerging treatment option for uterine factor infertility. Most uterus transplantation research programs use living donors, although this comes with considerable surgical and psychological risks and not all women desiring uterus transplantation will have an available living donor. A deceased donor program eliminates donor risks; however, the availability of deceased uterus donors is currently unknown in Australia. AIMS: To establish the feasibility of a deceased donor uterus transplantation program in Australia and consider expanded inclusion criteria for this model. MATERIALS AND METHODS: A retrospective review of the New South Wales (NSW) Organ and Tissue Donation Service database was undertaken to identify potential deceased uterus donors, with comparison to the broad deceased donor inclusion criteria from three international uterus transplantation trials including female, brain-dead, multi-organ donation, no major abdominal surgery, and <60 years of age. RESULTS: Between January 1, 2018, and December 31, 2022, 648 deceased donors were available in NSW. Of these, 43% (279/648) were female and 67% of the women (187/279) were also multi-organ donors. When the brain-dead donor-only and age criteria (<60 years) were applied, a total of 107 deceased donors met the available criteria for uterus transplantation, with an average of 21 deceased donors per year in NSW. CONCLUSIONS: There appears to be adequate deceased donor organ availability to establish a deceased uterus transplantation program in NSW, Australia. Should interest in uterus transplantation increase, including criteria such as older and nulliparous donors could increase organ availability for a uterus transplantation program.

Tolerogenic dendritic cells protect against acute kidney injury.

Ischemia reperfusion injury is a common precipitant of acute kidney injury that occurs following disrupted perfusion to the kidney. This includes blood loss and hemodynamic shock, as well as during retrieval for deceased donor kidney transplantation. Acute kidney injury is associated with adverse long-term clinical outcomes and requires effective interventions that can modify the disease process. Immunomodulatory cell therapies such as tolerogenic dendritic cells remain a promising tool, and here we tested the hypothesis that adoptively transferred tolerogenic dendritic cells can limit kidney injury. The phenotypic and genomic signatures of bone marrow-derived syngeneic or allogeneic, Vitamin-D3/IL-10-conditioned tolerogenic dendritic cells were assessed. These cells were characterized by high PD-L1:CD86, elevated IL-10, restricted IL-12p70 secretion and a suppressed transcriptomic inflammatory profile. When infused systemically, these cells successfully abrogated kidney injury without modifying infiltrating inflammatory cell populations. They also provided protection against ischemia reperfusion injury in mice pre-treated with liposomal clodronate, suggesting the process was regulated by live, rather than reprocessed cells. Co-culture experiments and spatial transcriptomic analysis confirmed reduced kidney tubular epithelial cell injury. Thus, our data provide strong evidence that peri-operatively administered tolerogenic dendritic cells have the ability to protect against acute kidney injury and warrants further exploration as a therapeutic option. This technology may provide a clinical advantage for bench-to-bedside translation to affect patient outcomes.

The impact of the cytoplasmic ubiquitin ligase TNFAIP3 gene variation on transcription factor NF-κB activation in acute kidney injury.

Nuclear factor κB (NF-κB) activation is a deleterious molecular mechanism that drives acute kidney injury (AKI) and manifests in transplanted kidneys as delayed graft function. The TNFAIP3 gene encodes A20, a cytoplasmic ubiquitin ligase and a master negative regulator of the NF- κB signaling pathway. Common population-specific TNFAIP3 coding variants that reduce A20's enzyme function and increase NF- κB activation have been linked to heightened protective immunity and autoimmune disease, but have not been investigated in AKI. Here, we functionally identified a series of unique human TNFAIP3 coding variants linked to the autoimmune genome-wide association studies single nucleotide polymorphisms of F127C; namely F127C;R22Q, F127C;G281E, F127C;W448C and F127C;N449K that reduce A20's anti-inflammatory function in an NF- κB reporter assay. To investigate the impact of TNFAIP3 hypomorphic coding variants in AKI we tested a mouse Tnfaip3 hypomorph in a model of ischemia reperfusion injury (IRI). The mouse Tnfaip3 coding variant I325N increases NF- κB activation without overt inflammatory disease, providing an immune boost as I325N mice exhibit enhanced innate immunity to a bacterial challenge. Surprisingly, despite exhibiting increased intra-kidney NF- κB activation with inflammation in IRI, the kidney of I325N mice was protected. The I325N variant influenced the outcome of IRI by changing the dynamic expression of multiple cytoprotective mechanisms, particularly by increasing NF- κB-dependent anti-apoptotic factors BCL-2, BCL-XL, c-FLIP and A20, altering the active redox state of the kidney with a reduction of superoxide levels and the enzyme super oxide dismutase-1, and enhancing cellular protective mechanisms including increased Foxp3+ T cells. Thus, TNFAIP3 gene variants represent a kidney and population-specific molecular factor that can dictate the course of IRI.

No Time to Die-How Islets Meet Their Demise in Transplantation.

Islet transplantation represents an effective treatment for patients with type 1 diabetes mellitus (T1DM) and severe hypoglycaemia unawareness, capable of circumventing impaired counterregulatory pathways that no longer provide protection against low blood glucose levels. The additional beneficial effect of normalizing metabolic glycaemic control is the minimisation of further complications related to T1DM and insulin administration. However, patients require allogeneic islets from up to three donors, and the long-term insulin independence is inferior to that achieved with solid organ (whole pancreas) transplantation. This is likely due to the fragility of islets caused by the isolation process, innate immune responses following portal infusion, auto- and allo-immune-mediated destruction and ß-cell exhaustion following transplantation. This review covers the specific challenges related to islet vulnerability and dysfunction that affect long-term cell survival following transplantation.

Attenuation of renal injury by depleting cDC1 and by repurposing Flt3 inhibitor in anti-GBM disease.

Previous studies found cDC1s to be protective in early stage anti-GBM disease through Tregs, but pathogenic in late stage Adriamycin nephropathy through CD8+ T cells. Flt3 ligand is a growth factor essential for cDC1 development and Flt3 inhibitors are currently used for cancer treatment. We conducted this study to clarify the role and mechanisms of effects of cDC1s at different time points in anti-GBM disease. In addition, we aimed to utilize drug repurposing of Flt3 inhibitors to target cDC1s as a treatment of anti-GBM disease. We found that in human anti-GBM disease, the number of cDC1s increased significantly, proportionally more than cDC2s. The number of CD8+ T cells also increased significantly and their number correlated with cDC1 number. In XCR1-DTR mice, late (day 12-21) but not early (day 3-12) depletion of cDC1s attenuated kidney injury in mice with anti-GBM disease. cDC1s separated from kidneys of anti-GBM disease mice were found to have a pro-inflammatory phenotype (i.e. express high level of IL-6, IL-12 and IL-23) in late but not early stage. In the late depletion model, the number of CD8+ T cells was also reduced, but not Tregs. CD8+ T cells separated from kidneys of anti-GBM disease mice expressed high levels of cytotoxic molecules (granzyme B and perforin) and inflammatory cytokines (TNF-α and IFN-γ), and their expression reduced significantly after cDC1 depletion with diphtheria toxin. These findings were reproduced using a Flt3 inhibitor in wild type mice. Therefore, cDC1s are pathogenic in anti-GBM disease through activation of CD8+ T cells. Flt3 inhibition successfully attenuated kidney injury through depletion of cDC1s. Repurposing Flt3 inhibitors has potential as a novel therapeutic strategy for anti-GBM disease.

The Utility of Spatial Transcriptomics for Solid Organ Transplantation.

Spatial transcriptomics (ST) measures and maps transcripts within intact tissue sections, allowing the visualization of gene activity within the spatial organization of complex biological systems. This review outlines advances in genomic sequencing technologies focusing on in situ sequencing-based ST, including applications in transplant and relevant nontransplant settings. We describe the experimental and analytical pipelines that underpin the current generation of spatial technologies. This context is important for understanding the potential role ST may play in expanding our knowledge, including in organ transplantation, and the important caveats/limitations when interpreting the vast data output generated by such methodological platforms.

Research trends in Australia and New Zealand Nephrology: basic science and gender equity in peril.

Basic science research remains fundamental to progress in clinical care, understanding of disease pathophysiology and underpinning the evolution of personalised medicine. Exposure to research is pivotal to educating students, but a declining profile of basic science research has the potential to erode research capacity further. The capacity for women to engage in research and remain in academia long term is continually challenged by negative gender-based experiences and institutional barriers. The authors explored themes and authorship of abstracts presented at Australia and New Zealand--based nephrology conferences, as a surrogate marker of trends in research activity and gender engagement. Basic science research and female senior authorship declined during the study period, which has serious implications for the future of nephrology.

The Evolving Role of Diagnostic Genomics in Kidney Transplantation.

Monogenic forms of heritable kidney disease account for a significant proportion of chronic kidney disease (CKD) across both pediatric and adult patient populations and up to 11% of patients under 40 years reaching end-stage kidney failure (KF) and awaiting kidney transplant. Diagnostic genomics in the field of nephrology is ever evolving and now plays an important role in assessment and management of kidney transplant recipients and their related donor pairs. Genomic testing can help identify the cause of KF in kidney transplant recipients and assist in prognostication around graft survival and rate of recurrence of primary kidney disease. If a gene variant has been identified in the recipient, at-risk related donors can be assessed for the same and excluded if affected. This paper aims to address the indications for genomic testing in the context for kidney transplantation, the technologies available for testing, the conditions and groups in which testing should be most often considered, and the role for the renal genetics multidisciplinary team in this process.

Nonutilization of Kidneys From Donors After Circulatory Determinant of Death.

Background: The expansion of donation after circulatory determination of death (DCDD) programs and unmet demands for kidney transplantation indicate that there is a need to improve the efficiency and utilization of these organs. Methods: We studied all DCDD donors retrieved for kidney transplantation in Australia between 2014 and 2019 and determined the factors associated with nonutilization using least absolute shrinkage and selection operator and random forest models. Self-organizing maps were used to group these donors into clusters with similar characteristics and features associated with nonutilization were defined. Results: Of the 762 DCDD donors, 116 (15%) were not utilized for kidney transplantation. Of the 9 clusters derived from self-organizing map, 2 had the highest proportions of nonutilized kidneys. Factors for nonutilization (adjusted odds ratio [95% confidence interval], per SD increase) were duration from withdrawal of cardiorespiratory support till death (1.38 [1.16-1.64]), admission and terminal serum creatinine (1.43 [1.13-1.85]) and (1.41 [1.16-1.73]). Donor kidney function and duration of warm ischemia were the main factors for clinical decisions taken not to use kidneys from DCDD donors. Conclusions: Donor terminal kidney function and the duration of warm ischemia are the key factors for nonutilization of DCDD kidneys. Strategies to reduce the duration of warm ischemia and improve post-transplant recipient kidney function may reduce rates of nonutilization.