Retromer associated sorting nexins SNX1, SNX4, and SNX27 and the trafficking and basolateral membrane population of the intermediate conductance calcium activated potassium channel (KCa3.1) in polarised epithelial cells

The intermediate conductance calcium (Ca 2+)-activated potassium (K+) channel (KCa3.1) is targeted to the basolateral membrane of polarised epithelial cells, and is also found in many nonepithelial cell types. KCa3.1 performs several fundamental roles, including the promotion of transepithelial ion transport, and the maintenance of a homeostatic equilibrium inside cells. Thus, KCa3.1 is found in a wide range of tissues, from epithelial to neural, and is involved in several disease states. These disease states include sickle-cell anaemia, cardiac fibrosis, and diabetic nephropathy, and paint KCa3.1 as a potential target for novel disease therapies. In order to create these novel disease therapies, it is vital to understand how KCa3.1 is trafficked within the cell. Functionally, KCa3.1 is trafficked from the ER to the Golgi in a manner dependent on Rab1, and from the Golgi to the plasma membrane in a manner dependent on Rab8. Additionally, KCa3.1 trafficking has been shown to require a functional cytoskeleton, as well as the motor protein Myocin-Vc. One trafficking pathway which may traffic KCa3.1 is the Retromer pathway. This pathway involves multiple protein complexes, including the cargo recognition complex, and the WASH complex, as well as multiple individual sorting nexin proteins. If KCa3.1 is found to interact with components of the Retromer pathway, it could lead to new disease therapies. This project examined the role of three distinct sorting nexin protein; SNX1, SNX4, and SNX27, on the trafficking and basolateral membrane population of KCa3.1 in polarised epithelial cells. In order to do this, Fischer Rat Thyroid cells transfected to stably express a KCa3.1-BLAP (biotin ligase acceptor peptide) construct, were transfected with SNX1, 4, or 27 specific siRNA, then grown on filters in order to achieve polarity. This allowed for the apical and basolateral membrane populations of KCa3.1 to be independently assessed. Immunoblots were used to determine the extent to which transfections were successful. In cells where the transfection was successful, the basolateral membrane population of KCa3.1 was determined by immunoblots. Additionally, Ussing chamber experiments were utilised in order to explore the effects of transfections on the KCa3.1 current when stimulated by the KCa3.1 opener 1-EBIO, or the KCa3.1 inhibitor clotrimazole. This project showed the first evidence of the endogenous expression of SNX1 and SNX27 in FRT cells, and confirmed expression of SNX4 in FRT cells, first discovered in the McDonald Lab. Following this demonstration, cells were transfected with 40 pM of either SNX1, SNX4, or SNX27 siRNA. The transfection with SNX1 siRNA resulted in a 44 ± 8% decrease in SNX1 protein levels, however, showed no significant decrease in the basolateral membrane population of KCa3.1, nor in the KCa3.1 sensitive current measured by Ussing chamber experiments was observed. The transfection with SNX4 showed a 62 ± 12% decrease in intracellular SNX4, however, similar to SNX1, a decrease in intracellular SNX4 did not appear to affect either the basolateral membrane population of KCa3.1, nor the KCa3.1 sensitive currents. Finally, the transfection of cells with SNX27 siRNA showed a 27 ± 4% decrease in the intracellular protein levels of SNX27. While knockdown of SNX27 did not elicit a significant change in the basolateral membrane population of KCa3.1, it did suggest the possibility of KCa3.1 missorting to the apical membrane, as there was a trend towards a significant increase in the apical membrane population of KCa3.1 in the SNX27 knockdown cells compared to the control cells (p = 0.0818; n=4). These results appear to be consistent with the notion that KCa3.1 is not recycled in polarised epithelial cells, and suggest that KCa3.1 is not trafficked via the Retromer pathway. While KCa3.1 does not appear to be trafficked via the Retromer pathway, there are still unknown factors regarding the trafficking of KCa3.1 which need to be explored, such as why KCa3.1 appears to be recycled in migratory cells. It is important to fully comprehend the trafficking mechanisms surrounding KCa3.1 in order to develop novel effective therapeutic techniques to combat pathophysiological conditions resulting from dysfunctional KCa3.1

Australia and New Zealand Islets and Pancreas Transplant Registry Annual Report 2018—Pancreas Waiting List, Recipients, and Donors

Background This is a synopsis of the registry report from the Australia and New Zealand islet and pancreas transplant registry. The full report is available at http://anziptr.org/reports/. Methods We report data for all solid organ pancreas transplant activity from inception in 1984 to end 2017. Islet-cell transplantation activity is reported elsewhere. Data analysis was performed using Stata software version 14 (StataCorp, College Station, TX). Results From 1984 to 2017 a total of 809 solid organ pancreas transplants have been performed in Australia and New Zealand, in 790 individuals. In 2017, 52 people received a pancreas transplant. By center, this was; Auckland (4), Monash (17), and Westmead (31). In 2017, 51 transplants were simultaneous pancreas kidney, whereas 1 was pancreas after kidney, and none were pancreas transplant alone. Conclusions The number of pancreas transplants performed in Australia and New Zealand was slightly lower in 2017 but continues to increase over time

Donor Characteristics of Pancreas Transplantation in Australia and New Zealand: A Cohort Study 1984-2014

Background The aim of this study was to audit the characteristics of pancreas donors over time in Australia and New Zealand. Pancreas transplantation was introduced in Australian and New Zealand in 1984. Methods We analyzed data from the Australia and New Zealand Islet and Pancreas Transplant Registry, 1984 to 2014. We investigated the variation of donor characteristics of sex, age, body mass index, smoking status, blood group, multiple organ donation, cytomegalovirus status, terminal creatinine, hypertension, and cause of death for pancreas transplantation over time. We used χ2 test (Fisher test when necessary) or analysis of variance to test difference for categorical or continuous characteristics, respectively. Results There were 628 pancreas donors from 1984 to 2014. Donor body mass index (from 21.9 to 24.0, P < 0.001) and age (from 23.9 to 28.5, P = 0.02) have both increased while terminal creatinine has decreased (86.3 to 73.3, P = 0.01) from 1995 to 2014. In the meantime, the proportions of donors with hypertension (from 19% to 1%, P < 0.001) and who were smokers (from 54% to 15%, P < 0.001) have decreased. Profile of cause of donor death has also changed over time (P = 0.06) with increase in cerebral hypoxia/ischemia (from 3% to 17%) and reductions in intracranial hemorrhage (27% to 13%). Conclusions Many donor characteristics have changed over time. The most significant changes appear to reflect changes in the general population, rather than changes in donor selection

A randomized, controlled trial of everolimus-based dual immunosuppression versus standard of care in de novo kidney transplant recipients

Kidney transplant recipients receiving calcineurin inhibitor-based immunosuppression incur increased long-term risks of cancer and kidney fibrosis. Switch to mammalian target of rapamycin (mTOR) inhibitors may reduce these risks. Steroid or Cyclosporin Removal After Transplant using Everolimus (SOCRATES), a 36-month, prospective, multinational, open-label, randomized controlled trial for de novo kidney transplant recipients, assessed whether everolimus switch could enable elimination of mycophenolate plus either steroids or CNI without compromising efficacy. Patients received cyclosporin, mycophenolate and steroids for the first 14 days then everolimus with mycophenolate and CNIwithdrawal (CNI- WD); everolimus with mycophenolate and steroid withdrawal (steroid-WD); or cyclosporin, mycophenolate and steroids (control). 126 patients were randomized. The steroid WD arm was terminated prematurely because of excess discontinuations. Mean eGFR at month 12 for CNI-WD versus control was 65.1 ml/ min/1.73 m2 vs. 67.1 ml/min/1.73 m2 by ITT, which met predefined noninferiority criteria (P = 0.026). The CNI-WD group experienced a higher rate of BPAR (31% vs. control 13%, P = 0.048) and showed a trend towards higher composite treatment failure (BPAR, graft loss, death, loss to follow-up). The 12 month results from SOCRATES show noninferiority in eGFR, but a significant excess of acute rejection when everolimus was commenced at week 2 to enable a progressive withdrawal of mycophenolate and cyclosporin in kidney transplant recipients.Steven J. Chadban, Josette Marie Eris, John Kanellis, Helen Pilmore, Po Chang Lee, Soo Kun Lim, Chad Woodcock, Nicol Kurstjens, Graeme Rus

Kidney Donor Profile Index and allograft outcomes: interactive effects of estimated post-transplant survival score and ischaemic time

Background. The Kidney Donor Profile Index (KDPI) is routinely reported by the donation agencies in Australia.We determined the association between KDPI and short-term allograft loss and assessed if this association was modified by the estimated post-transplant survival (EPTS) score and total ischaemic time. Methods. Using data from the Australia and New Zealand Dialysis and Transplant Registry, the association between KDPI (in quartiles) and 3-year overall allograft loss was examined using adjusted Cox regression analysis. The interactive effects between KDPI, EPTS score and total ischaemic time on allograft loss were assessed. Results. Of 4006 deceased donor kidney transplant recipients transplanted between 2010 and 2015, 451 (11%) recipients experienced allograft loss within 3 years post-transplant. Compared with recipients of kidneys with a KDPI of 0–25%, recipients who received donor kidneys with a KDPI >75% experienced a 2-fold increased risk of 3-year allograft loss {adjusted hazard ratio [HR] 2.04 [95% confidence interval (CI) 1.53–2.71]}. The adjusted HRs for kidneys with a KDPI of 26–50% and 51–75% were 1.27 (95% CI 0.94–1.71) and 1.31 (95% CI 0.96–1.77), respectively. There were significant interactions between KDPI and EPTS scores (P-value for interaction <.01) and total ischaemic time (P-value for interaction <.01) such that the associations between higher KDPI quartiles and 3-year allograft loss were strongest in recipients with the lowest EPTS scores and longest total ischaemic time. Conclusion. Recipients with higher post-transplant expected survival and transplants with longer total ischaemia who received donor allografts with higher KDPI scores experienced a greater risk of short-term allograft loss compared with those recipients with reduced post-transplant expected survival and with shorter total ischemia.Janelle Prunster, Germaine Wong, Nicholas Larkins, Kate Wyburn, Ross Francis, William R. Mulley, Esther Ooi, Helen Pilmore, Christopher E. Davies and Wai H. Li

Interactions between donor age and 12-month estimated glomerular filtration rate on allograft and patient outcomes after kidney transplantation

Reduced estimated glomerular filtration rate (eGFR) at 12-months after kidney transplantation is associated with increased risk of allograft loss, but it is uncertain whether donor age and types modify this relationship. Using Australia and New Zealand registry data, multivariable Cox proportional modelling was used to examine the interactive effects between donor age, types and 12-month eGFR on overall allograft loss. We included 11,095 recipients (4,423 received live-donors). Recipients with lowest 12-month eGFR (60 ml/min/1.73 m²) was 0.67 [0.62–0.74]. The association of 12-month eGFR and allograft loss was modified by donor age (but not donor types) where a higher risk of allograft loss in recipients with lower compared with higher 12-month eGFR being most pronounced in the younger donor age groups (p 60 ml/min/1.73 m², and the magnitude of the increased risk is most marked among recipients with younger donors. Careful deliberation of other factors including donor age when considering eGFR as a surrogate for clinical endpoints is warranted.Wai H. Lim, Esther Ooi, Helen L. Pilmore, David W. Johnson, Stephen P. McDonald, Philip Clayton, Carmel Hawley, William R. Mulley, Ross Francis, Michael G. Collins, Bryon Jaques, Nicholas G. Larkins, Christopher E. Davies, Kate Wyburn, Steve J. Chadban and Germaine Won

Carvedilol and cardiac biomarkers in dialysis patients: Secondary analysis of a randomized controlled trial

Published online: December 04, 2017Background/Aims: Cardiac biomarkers are associated with cardiac abnormalities and adverse outcomes in dialysis patients. Our aim was to report the effect of the beta-blocker carvedilol on cardiac biomarkers in adult dialysis patients. Methods: The Beta-Blocker to Lower Cardiovascular Dialysis Events Feasibility Study was a randomized controlled trial comparing carvedilol to placebo. Serum and plasma were collected before the run-in, then 6 and 12 months post-randomization to measure B-type Natriuretic Peptide (BNP), N-terminal BNP (NT-ProBNP), high-sensitivity cardiac troponins I (hs-TnI) and T (hs-TnT), and galectin-3. Left ventricular global longitudinal strain (GLS) was measured by echocardiography at baseline. Results: Seventy-two participants were recruited of whom 49 completed the run-in and were randomized to carvedilol (n=26) or placebo (n=23). Baseline echocardiography demonstrated median (inter-quartile range) GLS of -14.27% (-16.63 to -11.93). NTproBNP and hs-TnT correlated with GLS (Spearman’s rho=0.34 [p=0.018] and rho=0.28 [p=0.049], respectively). Median change scores from baseline to 12 months did not differ significantly between participants with complete biomarker data randomized to carvedilol (n=15) or placebo (n=16) for any biomarkers. Conclusions: NT-proBNP and hs-TnT were associated with GLS. However, changes in levels of the biomarkers from baseline to 12 months were not different between groups randomized to carvedilol and placebo.Matthew A. Roberts, Darsy Darssan, Sunil V. Badve, Robert P. Carroll, Magid A. Fahim, Brian A. Haluska, Carmel M. Hawley, Nicole M. Isbel, Mark R. Marshall, Elaine M. Pascoe, Eugenie Pedagogos, Helen L. Pilmore, Paul Snelling, Tony Stanton, Ken-Soon Tan, Andrew M. Tonkin, Liza A. Vergara, Francesco L. Ierin

Chronic kidney disease and valvular heart disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) is a major risk factor for valvular heart disease (VHD). Mitral annular and aortic valve calcifications are highly prevalent in CKD patients and commonly lead to valvular stenosis and regurgitation, as well as complications including conduction system abnormalities and endocarditis. VHD, especially mitral regurgitation and aortic stenosis, is associated with significantly reduced survival among CKD patients. Knowledge related to VHD in the general population is not always applicable to CKD patients because the pathophysiology may be different, and CKD patients have a high prevalence of comorbid conditions and elevated risk for periprocedural complications and mortality. This Kidney Disease: Improving Global Outcomes (KDIGO) review of CKD and VHD seeks to improve understanding of the epidemiology, pathophysiology, diagnosis, and treatment of VHD in CKD by summarizing knowledge gaps, areas of controversy, and priorities for research

Chronic Kidney Disease and Coronary Artery Disease: JACC State-of-the-Art Review

Chronic kidney disease (CKD) is a major risk factor for coronary artery disease (CAD). As well as their high prevalence of traditional CAD risk factors, such as diabetes and hypertension, persons with CKD are also exposed to other nontraditional, uremia-related cardiovascular disease risk factors, including inflammation, oxidative stress, and abnormal calcium-phosphorus metabolism. CKD and end-stage kidney disease not only increase the risk of CAD, but they also modify its clinical presentation and cardinal symptoms. Management of CAD is complicated in CKD patients, due to their\ua0likelihood of comorbid conditions and potential for side effects during interventions. This summary of the Kidney\ua0Disease: Improving Global Outcomes (KDIGO) Controversies Conference on CAD and CKD (including end-stage\ua0kidney disease and\ua0transplant recipients) seeks to improve understanding of the epidemiology, pathophysiology, diagnosis, and\ua0treatment of CAD in CKD and to identify knowledge gaps, areas of controversy, and\ua0priorities for research