Search

A 62-year-old woman presented with acute renal failure, hematuria, proteinuria, and increased C-reactive protein level. She was positive for antineutrophil cytoplasmic antibodies (ANCAs) directed against myeloperoxidase (MPO) and negative for anti-glomerular basement membrane antibody. Kidney biopsy confirmed a diagnosis of pauci-immune crescentic glomerulonephritis with no immunoglobulin G staining. Remission was induced with prednisolone and intravenous cyclophosphamide, followed by maintenance therapy with azathioprine, during which MPO-ANCA results became negative. Nine months after the initial presentation, kidney function rapidly deteriorated again in association with hematuria, proteinuria, and increased C-reactive protein level. A second kidney biopsy again showed crescentic glomerulonephritis; however, on this occasion, direct immunofluorescence showed prominent linear staining of the glomerular basement membrane with immunoglobulin G. Test results were strongly positive for glomerular basement membrane antibody, but remained negative for MPO-ANCA. HLA-DR typing showed HLA-DRB1*15011, an allele strongly associated with anti-glomerular basement membrane disease. To our knowledge, this is the only reported case of 2 distinct forms of crescentic glomerulonephritis characterized by separate autoantibody profiles developing sequentially in a patient with proved HLA susceptibility. We speculate that glomerular damage caused by the initial renal insult resulted in a subsequent autoimmune response to autoantigen presented on the HLA-DR susceptibility allele. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is a major cause of morbidity and mortality, contributing to approximately 20 000 deaths in 2021 in Australia. Importantly, progression of CKD can be substantially reduced if it is detected and treated early. Here we present the perspectives of a general practitioner (primary care physician), a nephrologist and a patient advocate on how the diagnosis and management of CKD in primary care could be improved. Early detection and treatment of CKD are impeded by limited patient awareness and knowledge, communication challenges between patients and doctors, and psychosocial issues, with these factors also interacting with, and exacerbating, each other. We make the following recommendations to help improve outcomes in patients with CKD: (1) identifying people at increased risk of CKD and ensuring they have a complete kidney health check (including estimated glomerular filtration rate, urine albumin-creatinine ratio and a blood pressure check) every 1-2 years; (2) using simple, nonconfrontational language and supportive resources to communicate with patients about kidney health; (3) implementing early treatment to slow the progression of CKD and avoid adverse cardiovascular disease outcomes; and (4) asking patient-orientated questions to support shared decision-making and empower patients to be active partners in their healthcare. We acknowledge that limited time is a major barrier to implementing these recommendations in primary care. Utilizing the expertise of the whole practice team, and adopting supportive technology to introduce efficiencies, are likely to be of benefit. By adopting these recommendations, we believe general practitioners have the opportunity to drive improved outcomes and quality of life for people living with CKD in Australia., Competing Interests: BR has participated in advisory boards for AstraZeneca and GSK. GD has no financial conflicts of interests related to the content of this article but has provided educational and advisory board consultancy to AstraZeneca. RKSP has received consultancy fees and honoraria from AstraZeneca, Novo Nordisk and Sanofi-Genzyme and travel support from Novartis. AstraZeneca reviewed the final draft of the manuscript for medical accuracy prior to submission; any resulting comments were translated to the authors for their consideration and incorporated at the authors’ discretion. Oxford PharmaGenesis, Melbourne, Australia has received funding from AstraZeneca to support the writing of this article., (© The Author(s) 2024.)

Introduction: First Nations Australians display remarkable strength and resilience despite the intergenerational impacts of ongoing colonisation. The continuing disadvantage is evident in the higher incidence, prevalence, morbidity and mortality of chronic kidney disease (CKD) among First Nations Australians. Nationwide community consultation (Kidney Health Australia, Yarning Kidneys, and Lowitja Institute, Catching Some Air) identified priority issues for guideline development. These guidelines uniquely prioritised the knowledge of the community, alongside relevant evidence using an adapted GRADE Evidence to Decision framework to develop specific recommendations for the management of CKD among First Nations Australians., Main Recommendations: These guidelines explicitly state that health systems have to measure, monitor and evaluate institutional racism and link it to cultural safety training, as well as increase community and family involvement in clinical care and equitable transport and accommodation. The guidelines recommend earlier CKD screening criteria (age ≥ 18 years) and referral to specialists services with earlier criteria of kidney function (eg, estimated glomerular filtration rate [eGFR], ≤ 45 mL/min/1.73 m 2 , and a sustained decrease in eGFR, > 10 mL/min/1.73 m 2 per year) compared with the general population., Changes in Management as Result of the Guidelines: Our recommendations prioritise health care service delivery changes to address institutional racism and ensure meaningful cultural safety training. Earlier detection of CKD and referral to nephrologists for First Nations Australians has been recommended to ensure timely implementation to preserve kidney function given the excess burden of disease. Finally, the importance of community with the recognition of involvement in all aspects and stages of treatment together with increased access to care on Country, particularly in rural and remote locations, including dialysis services., (© 2023 The Authors. Medical Journal of Australia published by John Wiley & Sons Australia, Ltd on behalf of AMPCo Pty Ltd.)

Aim: Diabetes, hypertension and smoking may contribute to the development and progression of chronic kidney disease (CKD) and its complications. The aim of this study was to assess patients' awareness and beliefs about these and other risk factors associated with CKD., Methods: Participants with CKD Stages 1-5 were purposively sampled for participation in a mixed methods study. Focus group participants completed a survey on CKD risk factors and discussed the reasons for their choices. Thematic analysis was used to analyse the qualitative data., Results: Of the 38 participants, the proportion who identified hypertension, family history, diabetes and obesity as risk factors for CKD were 89%, 87%, 87% and 70% respectively. Only 54% and 38% recognized that smoking and Aboriginal or Torres Strait Islander status were risk factors. Participants considered the risks of heart attack, stroke and premature mortality to be 20-40% lower in people with CKD than those with diabetes or pre-existing cardiovascular disease. Five themes were identified: invisibility (lack of signs and symptoms of CKD), invincibility (participants did not feel they were at risk), lacking awareness (identified not knowing much about their disease), cumulative comorbidities (concerned about the increased risks of associated diseases) and inevitability of death (there is no cure for CKD)., Conclusion: Participants had good understanding of some risk factors for CKD (hypertension and diabetes) but limited understanding of others. Awareness of comorbidities was also less than for other chronic conditions. Compared with diabetes and cardiovascular disease, CKD was perceived to pose less of a threat to life. Patient education that addresses CKD risk factors, comorbidities and outcomes may increase awareness and foster better self-management for people with CKD., (© 2016 Asian Pacific Society of Nephrology.)

Background: Advanced training programmes in nephrology should provide broad exposure to all aspects of nephrology. In Australia and New Zealand (ANZ), the Advanced Training Committee in Nephrology oversees training, and recent increases in trainee numbers have led to concern about dilution of experience., Aim: To investigate early career paths of nephrologists in ANZ and determine the adequacy of training by comparing self-determined competency and skill relevance among recently graduated nephrologists., Methods: In 2015, the Advanced Training Committee in Nephrology administered an online survey during the annual subscription for members of the Australian and New Zealand Society of Nephrology. Nephrologists who were awarded Fellowship after 2002 were invited to participate., Results: The survey was completed by 113 Fellows with 8 respondents excluded (response rate 44.1%). Initial post-Fellowship work included full-time public hospital appointments (34.3%) or undertaking full-time higher research degrees (41.9%). The majority reported securing their desired employment. Respondents indicated adequate training in most clinical skills; however, responses of 'well trained' in home haemodialysis (41.8%), conservative care (42.9%), automated peritoneal dialysis (38.8%), and assessment of kidney transplant recipients (48%) and living kidney donors (34.7%) were less adequate. Although considered highly relevant to current practice, responses of 'well trained' were low for management and research skills, including complaint management (16.3%), private practice management (2%), health system knowledge (14.3%) and regulations (6.1%), ethics approval (23.5%), research funding (11.2%) and quality assurance (26.5%)., Conclusion: Nephrology training in ANZ generally meets clinical needs and most secure their desired employment. Training in management and research are areas for improvement., (© 2016 Asian Pacific Society of Nephrology.)

Background: Patients with early-stage chronic kidney disease (CKD) must make lifestyle modifications and adhere to treatment regimens to prevent their progression to end-stage kidney disease. The aim of this study was to elicit the perspectives of patients with stage 1-4 CKD about their disease, with a specific focus on their information needs in managing and living with CKD and its sequelae., Methods: Patients with CKD stages 1-4 were purposively sampled from three major hospitals in Sydney, Australia to participate in focus groups. Transcripts were thematically analysed., Results: From nine focus groups including 38 participants, six major themes were identified: medical attentiveness (shared decision-making, rapport, indifference and insensitivity); learning self-management (diet and nutrition, barriers to physical activity, medication safety); contextualizing comorbidities (prominence of CKD, contradictory treatment); prognostic uncertainty (hopelessness, fear of disease progression, disbelief regarding diagnosis); motivation and coping mechanisms (engage in research, pro-active management, optimism, feeling normal); and knowledge gaps (practical advice, access to information, comprehension of pathology results and CKD diagnosis, education for general practitioners)., Conclusion: Patients capacity to slow the progression of CKD may be limited by their lack of knowledge about the disease, its comorbidities, psychosocial influences and their ability to interact and communicate effectively with their health-care provider. Support from a multidisciplinary care team, combined with provision of comprehensive, accessible and practical educational resources may enhance patients' ability and motivation to access and adhere to therapeutic and lifestyle interventions to retard progression of CKD., (© 2014 Asian Pacific Society of Nephrology.)

Background: Advanced training in nephrology should provide broad experience in all aspects of nephrology. In Australia, the Specialist Advisory Committee in Nephrology oversees nephrology training, and recent increases in advanced trainee numbers have led to concern about dilution of training experience. No study has examined variations in clinical exposure for nephrology trainees in Australia., Aim: To assess the changes in nephrology advanced training in Australia with respect to trainee numbers and exposure to patients and procedures over the past 10 years., Methods: A retrospective study was performed by obtaining all available Royal Australasian College of Physician supervisor reports from 2000 to 2010 to determine differences in clinical exposure and procedures performed by nephrology trainees., Results: Five hundred and forty-two reports were reviewed involving 208 nephrology trainees in Australia across 53 different training sites. In 2000, 22 trainees were undertaking a core clinical year of training. Trainee numbers have steadily risen from 33 in 2004 to 84 in 2010. The greatest increases have occurred in New South Wales, Victoria and Queensland (sixfold, threefold and fivefold increases respectively). Trainee exposure to dialysis patients has gradually decreased in the past decade. The average number per trainee per year in 2000 compared with 2010 were 66 versus 43 (P = 0.02) and 28 versus 16 (P = 0.01) for haemodialysis and peritoneal dialysis respectively. Acute kidney injury cases per trainee showed a gradual nonsignificant reduction over time and average procedural numbers per trainee decreased significantly from 2000 to 2010 with fewer temporary dialysis catheters inserted per year (39 vs 10, P < 0.01) and fewer renal biopsies performed per year (65 vs 41, P < 0.01). The proportion of trainees working in a hospital that does not provide exposure to acute transplantation has steadily increased from 15% in 2003 to 44% in 2010., Conclusions: There has been a dramatic and significant increase in nephrology advanced trainee numbers over the past decade at a more rapid rate than the growth in dialysis and transplant patient numbers. This study suggests that training experience has diminished over the past decade and supports a 3-year core clinical nephrology training programme in Australia., (© 2012 The Authors; Internal Medicine Journal © 2012 Royal Australasian College of Physicians.)

Monocytes utilise a variety of chemokines to traffic to atherosclerotic plaques. CX3C chemokine ligand 1 (CX3CL1 & Fractalkine) and its receptor CX3CR1 and monocyte chemoattractant protein 1 (CCL2) have been identified as chemokines/receptors that have an important role in the migration and recruitment of monocytes during the pathogenesis of several inflammatory diseases including atherosclerosis. DNA vectors containing single chain variable region fragment (scFv) for DC-targeted receptor DEC205 were cloned with mouse CX3CR1 and CCL2 genes respectively, and vaccinated into C57/BL6 mice weekly for 3 weeks. Induced anti-CX3CR1 and anti-CCL2 in vaccinated mice was examined by ELISA and Western Blot analysis, while the cellular response was examined by ELISPOT. The inhibition of chemotaxis of J774 macrophages to Py-4-1 endothelial cells was examined by in vitro transwell migration assay using serum collected from vaccinated mice. All vaccinated mice generated anti-CX3CR1 and anti-CCL2 Ab and cellular response by 8 weeks after DNA vaccination. Macrophage migration towards TNF-α activated endothelial cells was significantly inhibited by serum containing both anti-CX3CR1 or anti-CCL2 Ab from vaccinated mice. These results demonstrate that DC-targeting of DNA vaccines to self-antigens generates functional immune responses which can inhibit specific key chemotactic targets. This suggests a potential therapeutic role for chemokine/receptor DNA vaccination in atherosclerosis, where chemotaxis has a pivotal role in the inflammatory process.

Experimental crescentic glomerulonephritis is driven by systemic cellular immune responses. A pathogenic role for T helper type 1 (Th1) and Th17 cells is well established. T-bet, a key transcription factor required for Th1 lineage commitment, and retinoic acid-related orphan receptor-γt (Rorγt), a key Th17 transcription factor, are required for full expression of disease. Similarly, several Th1- and Th17-associated cytokines have been implicated in disease augmentation. The role of Th2 cells in the disease is less clear, although Th2-associated cytokines, interleukin (IL)-4 and IL-10, are protective. We sought to determine the role of signal transducer and activation of transcription 6 (STAT6), a key regulator of Th2 responses, in experimental crescentic glomerulonephritis. Compared to wild-type mice, histological and functional renal injury was enhanced significantly in STAT6(-/-) mice 21 days after administration of sheep anti-mouse glomerular basement membrane globulin. Consistent with the enhanced renal injury, both Th1 and Th17 nephritogenic immune responses were increased in STAT6(-/-) mice. Conversely, production of IL-5, a key Th2-associated cytokine, was decreased significantly in STAT6(-/-) mice. Early in the disease process systemic mRNA expression of T-bet and Rorγ was increased in STAT6(-/-) mice. We conclude that STAT6 is required for attenuation of Th1 and Th17 nephritogenic immune responses and protection from crescentic glomerulonephritis., (© 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.)

Despite its initially defined role as a T-helper type 1 cell (Th1)-inducing cytokine, interleukin-27 (IL-27) has complex roles in vivo. The role of IL-27 receptor (IL-27R) was defined in experimental crescentic glomerulonephritis induced by a foreign antigen, sheep globulin, which is planted in glomeruli. This lesion is dependent on a Th1 effector cellular response. Twenty-one days after the administration of sheep anti-mouse glomerular basement membrane antibody, wild-type mice developed histologic and functional inflammatory renal injury. Injury was attenuated in the absence of IL-27R α chain (IL-27Rα), the unique component of the IL-27R complex. In contrast to the attenuated renal injury on day 21, Il27ra(-/-) mice exhibited enhanced systemic immune responses, including Th1 responses, with increased IL-2-dependent interferon-γ (IFN-γ) production. However, earlier in the development of the nephritogenic immune response, IFN-γ production was decreased, with reduced early immune responses translating into attenuated renal injury. Having demonstrated decreased early Th1 systemic immune responses, followed by enhanced nephritogenic Th1 immune responses, renal injury was studied at later time points. On days 28 and 35 after injection of the nephritogenic antigen, renal injury was enhanced in Il27ra(-/-) mice compared with wild-type mice in an at least partially IFN-γ-dependent manner. In Th1-dependent autoinflammatory lesions, IL-27Rα has a biphasic role in vivo, initially pathogenic, but ultimately playing a protective role by regulating immune responses and attenuating disease., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Aim: Statins are widely used for their cholesterol-lowering effects and for prevention of cardiovascular disease. Evidence indicates that these drugs also have immunomodulatory and other non-lipid lowering effects, with studies suggesting benefit in some animal models of immune (particularly T helper (Th)1)-mediated inflammatory disease and their corresponding human disease counterparts. We sought to evaluate the immunomodulatory effects and therapeutic potential of atorvastatin in experimental crescentic glomerulonephritis, a Th1-predominant animal model of glomerulonephritis., Methods: Autologous phase, anti-glomerular basement membrane glomerulonephritis was induced in C57BL/6 mice by intravenous injection of sheep anti-mouse glomerular basement membrane globulin. Mice were administered atorvastatin (10 or 100 mg/kg) or control (phosphate-buffered saline) daily by oral gavage. Immune responses and renal injury were assessed after 21 days., Results: Compared with control-treated mice, treatment with atorvastatin did not alter renal injury (serum creatinine, proteinuria, glomerular crescent formation) or glomerular leukocytic infiltration (CD4(+) T cells or macrophages). Atorvastatin resulted in a dose-related increase in circulating serum antibody to the disease-inducing antigen but no differences in antigen-stimulated splenocyte production of Th1/Th2 cytokines. At the higher dose, atorvastatin also led to a significant reduction in apoptosis of splenic CD4(+) T lymphocytes., Conclusion: This study demonstrates that statins modulate humoral responses and alter splenic CD4(+) T cell apoptosis. However, atorvastatin does not lead to significant changes in T helper cell polarization or renal injury in experimental crescentic glomerulonephritis.

The autoantigen in Goodpasture disease is the noncollagenous domain of alpha3 type IV collagen [alpha3(IV)NC1]. We previously demonstrated that IL-12p40(-/-) mice are protected from experimental autoimmune anti-glomerular basement membrane (anti-GBM) glomerulonephritis, seemingly defining a role for IL-12 in this disease; however, the recent identification of IL-23, a heterodimer composed of IL-12p40 and IL-23p19 subunits, raises the possibility that IL-23, rather than IL-12, may modulate this disease instead. We immunized wild-type, IL-12p35(-/-) (IL-12 deficient, IL-23 intact), IL-12p40(-/-) (deficient in both IL-12 and IL-23), and IL-23p19(-/-) (IL-12 intact, IL-23 deficient) mice with recombinant mouse alpha3(IV)NC1. Wild-type mice developed autoreactivity to alpha3(IV)NC1: Humoral responses, cellular responses, renal histologic abnormalities, leukocyte accumulation, autoantibody deposition, and IL-17A mRNA expression (a cytokine produced by the IL-23-maintained Th17 subset). IL-23 but not IL-12 was detected in the immune system. Regardless of the presence of IL-12, mice deficient in IL-23 were protected, but mice with IL-23 were not. Both IL-23-deficient strains exhibited lower autoantibody titers, reduced cellular reactivity, diminished cytokine production (IFN-gamma [Th1], IL-17A [Th17], TNF, and monocyte chemoattractant protein 1), and less renal disease and glomerular IgG deposition. The deficient responses in the absence of IL-23 were not due to increased regulatory T cells; IL-12p40(-/-) and IL-23p19(-/-) mice did not show increased proportions of CD4(+)CD25(+)FoxP3(+) cells or IL-10 levels early in the immune response. In conclusion, autoreactivity to the Goodpasture antigen is directed primarily by IL-23, absence of which results in hyporeactivity including but extending beyond a deficient Th17 response.

T-bet is a transcription factor that is essential for T helper (Th)1 lineage commitment and optimal IFN-gamma production by CD4(+) T cells. We examined the role of T-bet in the development of experimental crescentic glomerulonephritis, which is induced by Th1-predominant, delayed-type hypersensitivity-like responses directed against a nephritogenic antigen. Anti-glomerular basement membrane (GBM) glomerulonephritis was induced in T-bet(-/-) and wild-type C57BL/6 mice. Compared with wild-type controls, renal injury was attenuated in T-bet(-/-) mice with glomerulonephritis, evidenced by less proteinuria, glomerular crescents, and tubulointerstitial inflammation. Accumulation of glomerular CD4(+) T cells and macrophages was decreased, and was associated with reduced intrarenal expression of the potent Th1 chemoattractants CCL5/RANTES and CXCL9/Mig. Supporting the pro-inflammatory nature of T-bet signaling, assessment of systemic immunity confirmed that T-bet(-/-) mice had a reduction in Th1 immunity. The kinetic profile of T-bet mRNA in wild-type mice supported the hypothesis that T-bet deficiency attenuates renal injury in part by shifting the Th1/Th2 balance away from a Th1 phenotype. Expression of renal and splenic IL-17A, characteristically expressed by the Th17 subset of effector T cells, which have been implicated in the pathogenesis of autoimmune disease, was increased in T-bet(-/-) mice. We conclude that T-bet directs Th1 responses that induce renal injury in experimental crescentic glomerulonephritis.

Peripheral neuropathy is present in 65% of patients with end-stage kidney disease (ESKD). No cause is yet established: nerve excitability studies have shown that axons are chronically depolarized, primarily owing to hyperkalaemia, but in vitro studies have suggested a role for axonal Na+/K+ pump dysfunction. To investigate Na+/K+ pump activity in vivo, lower limb ischaemia was induced in five ESKD patients and six healthy controls by a sphygmomanometer cuff, inflated to 200 mm Hg and maintained for 13 min. The peroneal nerve was stimulated at the fibular neck and excitability parameters were recorded from tibialis anterior (TA) and extensor digitorum brevis (EDB) before, during and after the ischaemic period. Baseline excitability studies in ESKD patients demonstrated reductions in threshold electrotonus and superexcitability and increased refractoriness, consistent with membrane depolarization. During ischaemia, threshold increased in ESKD patients [by +23.6 +/- 5.0% (TA); +32.1 +/- 7.3% (EDB)] in contrast to the persistent threshold reduction observed in normal controls [-2.4 +/- 5.2% (TA); -13.0 +/- 8.2% (EDB); P < 0.01]. These changes were accompanied by increased refractoriness and reduced superexcitability in both ESKD and control groups, consistent with ischaemic depolarization. Conversely, there was reduction in strength-duration time constant towards the end of ischaemia. Following release of ischaemia, the marked increase in threshold observed in normal controls was not evident in ESKD patients, but the rapid return of threshold to baseline argues against significant Na+/K+ pump dysfunction. The abnormal pattern of response to ischaemia in the ESKD patients was not fully explained by the hyperkalaemic membrane depolarization and suggests that another dialysable factor affects nerve excitability in ESKD patients, most likely H(+) ions, but that this factor only becomes evident during ischaemia. Blockade of persistent Na+ conductances by H+ would also explain the reduction in strength-duration time constant observed during ischaemia.

Objective: To investigate the mechanisms underlying peripheral neuropathy and to provide insights into axonal Na(+)/K(+) pump function in patients with end-stage kidney disease (ESKD)., Methods: Nerve excitability was assessed in 10 ESKD patients before and after a single session of haemodialysis and in 29 age-matched control subjects. Changes in excitability were recorded at baseline and following maximal voluntary contraction (MVC) of abductor pollicis brevis (APB) for 60s. Serum concentrations of putative neurotoxins including potassium, urea, parathyroid hormone and beta-2-microglobulin were also measured., Results: Baseline excitability values were consistent with axonal depolarisation prior to dialysis. Following maximal voluntary contraction (MVC), there was an increase in threshold, which was associated with reduced strength-duration time constant and increased superexcitability, consistent with axonal hyperpolarisation. These changes were quantitatively similar for patients and controls, arguing against any significant reduction in the axonal Na(+)/K(+) pump in ESKD. Following dialysis, activity-dependent changes were less in ESKD, which suggests greater Na(+)/K(+) pump activity prior to dialysis, the opposite of the changes expected with reduced Na(+)/K(+) pump function. The reduced post-contraction threshold change in post-dialysis recordings is likely to be secondary to relative hyperpolarisation of the axonal membrane following dialysis and reduction in K(+) concentration., Conclusions: Our findings suggest that Na(+)/K(+) pump function is not impaired in patients with ESKD., Significance: Pre-dialysis excitability changes in ESKD patients may be explained on the basis of hyperkalaemia. Alteration in Na(+)/K(+) pump function does not appear to be a contributing factor to the development of neuropathy in ESKD patients.

Background: Peripheral neuropathy is present in 65% of patients with end stage kidney disease (ESKD) starting dialysis. Studies of membrane potential and axonal ion channel function may help explain the pathophysiology., Objectives: To follow changes in median sensory axon excitability in patients with ESKD treated with haemodialysis, and correlate them with clinical rating scales and serum levels of potential neurotoxins., Methods: Sensory nerve action potentials were recorded from the second digit following stimulation of the median nerve in 12 ESKD patients. Stimulus-response behaviour using two stimulus durations, threshold electrotonus to 100 ms polarising currents, a current-threshold relation, and recovery of excitability following supramaximal stimulation were recorded before, during, and after haemodialysis. Serum concentrations of potential neurotoxins were measured., Results: Before dialysis, there were changes in nerve excitability consistent with axonal depolarisation: refractoriness was increased; superexcitability and depolarising threshold electrotonus were reduced. Following dialysis there were improvements in all indices, with correlations between excitability abnormalities and serum potassium measurements. Neuropathic symptoms correlated with excitability changes., Conclusions: Nerves are depolarised before haemodialysis in ESKD patients. The correlation of excitability abnormalities with potassium indicates that the achievement of normokalaemia should be a priority in treating such patients.

Although multiple toxins have been implicated in the development of uraemic neuropathy, no causative agent has been identified. In the present study, the excitability properties of lower limb motor nerves in patients with end-stage kidney disease treated with haemodialysis were measured before, during and after a standard 5 h haemodialysis session, in an attempt to explore the pathophysiology of uraemic neuropathy. Compound muscle action potentials were recorded from tibialis anterior and extensor digitorum brevis, following stimulation of the common peroneal nerve in 14 patients. Measures of excitability were assessed in relation to changes in serum levels of potential neurotoxins, including potassium, calcium, urea, uric acid, parathyroid hormone and beta-2-microglobulin. Before dialysis, measures of nerve excitability were significantly abnormal in the patient group for axons innervating tibialis anterior and extensor digitorum brevis, consistent with axonal depolarization: refractoriness was increased and superexcitability and depolarizing threshold electrotonus were reduced. Pre-dialysis excitability abnormalities were strongly correlated with serum K+. Correlation was also noted between the severity of symptoms and excitability abnormalities. Haemodialysis normalized the majority of nerve excitability parameters. In conclusion, lower limb motor axons in uraemic patients are depolarized before dialysis. The correlation between serum K+ and excitability measures indicates that hyperkalaemia is primarily responsible for uraemic depolarization, and a likely contributing factor to the development of neuropathy.

The role of the HPA axis in blood pressure regulation was examined in 6 normal male volunteers by comparing haemodynamic and hormonal effects of placebo, captopril, and dexamethasone given in random order for two days. The average 24-hour systolic and mean arterial pressures on placebo (135 +/- 6 and 93 +/- 2 mmHg respectively) were significantly higher than on captopril (118 +/- 1 and 85 +/- 1 mmHg respectively, p < 0.05) but there were no significant changes on dexamethasone compared with placebo (128 +/- 3 and 89 +/- 3 mmHg respectively). There were no differences in the average 24-hour diastolic blood pressures or heart rates, nor the day-night differences, night:day ratios or percentage changes in blood pressure and heart rate between treatments. Captopril significantly increased active plasma renin concentration, whilst dexamethasone decreased cortisol concentration. These results confirm the role of the renin-angiotensin system in the regulation of blood pressure in normal subjects but suggest that the HPA axis does not play a major role in determining ambulatory blood pressure or day-night variability in the short term.