Expression of NEDD4L and ENaC in Urinary Extracellular Vesicles in Pre-eclampsia.

OBJECTIVE: To assess changes in expression of renal epithelial sodium channel (ENaC) and NEDD4L, a ubiquitin ligase, in urinary extracellular vesicles (UEV) of pre-eclamptic women compared to normal pregnant controls. METHODS: Urine was collected from pre-eclamptic women (PE, n = 20) or during normal pregnancy (NP, n = 20). UEV were separated by differential ultracentrifugation. NEDD4L, α-ENaC and γ-ENaC were identified by immunoblotting. RESULTS: There was no difference in the expression of NEDD4L (p = 0.17) and α-ENaC (p = 0.10). PE subjects showed increased expression of γ-ENaC by 6.9-fold compared to NP (p < 0.0001). CONCLUSION: ENaC expression is upregulated in UEV of pre-eclamptic subjects but was not associated with changes in NEDD4L.

A case of ANCA-associated vasculitis presenting de novo in pregnancy, successfully treated with rituximab.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitides are rare small vessel vasculitides of unknown cause. The pathogenic role of MPO-ANCA in the vasculitides has been supported using various animal models, with B-cells playing a role in the disease pathogenesis. Pregnancy in the presence of an autoimmune disease such as vasculitis is often associated with significant morbidity. Little is known about the outcomes when women present with de novo vasculitis during pregnancy, and the appropriate management of such presentations is unclear. We describe a case of a 33-year-old female presenting in her second pregnancy with new onset ANCA vasculitis at 12 weeks' gestation. She was successfully treated with prednisolone and rituximab, and delivered a healthy 2.8 kg boy at 36 weeks' gestation with no clinical manifestations of vasculitis or neutropenia in the neonate.

Increased expression and phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoforms in urinary exosomes in pre-eclampsia.

BACKGROUND: Glycolysis is altered in various kidney diseases, but little is known about glycolysis in pre-eclampsia, a multi-system disorder with major pathological effects on the kidney. Urinary exosomes provide a non-invasive alternative for studying changes in kidney metabolism. This study aims to characterise the expression and phosphorylation of isozymes of the key glycolytic regulatory protein, 6-phosphofructokinase-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), in urinary exosomes of subjects with pre-eclampsia (PE), compared to normotensive non-pregnant (NC) and normotensive pregnant (NP) controls. METHODS: A cross-sectional study of NC (n = 19), NP (n = 23) and PE (n = 29) subjects was performed. Exosomes were isolated from urine samples by differential ultracentrifugation, and then analyzed by Western blot and densitometry for expression of PFK-2/FBPase-2 isozymes (PFKFB2, PFKFB3 and PFKFB4) and phosphorylation of PFKFB2 at residues Ser483 and Ser466 and PFKFB3 at Ser461. RESULTS: PFKFB2 expression was increased 4.7-fold in PE compared to NP (p < 0.001). PFKFB2 phosphorylation at Ser483 was increased 2.6-fold in PE compared to NP (p = 0.002). Expression of phosphorylated PFKFB2/PFKFB3 at Ser466/Ser461 was increased in PE, being present in 77.4% (95% CI 59.9-88.9%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB3 was more commonly expressed in PE, detected in 90.3% (95% CI 74.3-97.4%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB4 had a 7.2-fold increase in expression in PE compared to NP (p < 0.001). No significant differences between NP and NC groups were observed. CONCLUSION: Regulatory proteins that increase glycolysis are increased in the urinary exosomes of subjects with pre-eclampsia, suggesting that renal glycolysis may be increased in this condition.

Results of an Aboriginal community-based renal disease management program incorporating point of care testing for urine albumin:creatinine ratio.

INTRODUCTION: There has been a significant increase in the burden of renal disease among Aboriginal Australians over the past 15 years. Urine albumin:creatinine ratio (ACR) is a well-established marker of microalbuminuria and can be conveniently performed on the DCA 2000 point-of-care testing (POCT) analyser (Bayer Australia; Melbourne, VIC, Australia) with an on-site result available in 7 min. The application of the urine ACR POCT for renal disease risk assessment was pioneered by our group in the Umoona Kidney Project. This article describes the results of the management arm of the Umoona Kidney Project, which used point-of-care urine ACR testing for the first time within a management framework to monitor albuminuria in patients at highest risk of renal disease. The article also examines the analytical quality of POCT results and overall community acceptance of the Umoona Kidney Project. METHODS: Adults clinically assessed by Flinders Medical Centre renal specialists as being at greatest risk for renal disease were offered the ACE inhibitor (ACEI) perindopril on a voluntary basis. Selected renal markers, including POCT urine ACR (conducted on-site by Umoona's Aboriginal health worker team), plasma electrolytes, urea, creatinine, calculated glomerular filtration rate and blood pressure were measured six monthly. Regular quality control testing was undertaken to monitor the analytical performance of the POCT analyser. A culturally appropriate questionnaire was designed and implemented to assess community satisfaction with the project. RESULTS: In all, 231 patient management consultations were conducted over a two year period, with over 70% of patients having four or more (up to a maximum of eight) consultations; 35 patients (mean age 49.2 [+/-2.3] years, 54% males) participated voluntarily in the management arm. All were overtly hypertensive, hypertensive with other risk factors or had diabetes. The renal status of these patients was followed for a mean of 63 +/- 4.5 weeks. In total, 111 POCT urine ACR tests were performed for patient management (mean 3.2 tests per patient). There was no significant difference in POCT urine ACR in the study period with a median (and inter-quartile range) of 5.7 mg/mmol (1.2-15.2) pre-ACEI and 4.3 mg/mmol (1.3-16.7) post-ACEI treatment (p = 0.50, Wilcoxon signed ranks test). The calculated glomerular filtration rate altered from 110 to 118 mL/min (p = 0.019, paired t-test). There was no change in the group plasma potassium, urea and creatinine. Collectively these results indicate a stabilisation in renal function among the management group. Blood pressure (both lying and standing) fell significantly in the study period. The imprecision for urine ACR quality control POCT conducted during the management program was within nationally and internationally accepted precision goals for urine albumin, creatinine and ACR. Fifty community members completed the satisfaction questionnaire. Three-quarters of respondents felt there were no cultural barriers in providing a urine sample for urine ACR POCT. CONCLUSIONS: The management arm of the Umoona Kidney Project was effective in stabilising the renal function and improving the blood pressure of community members identified to be at greatest risk of kidney disease. POCT urine ACR testing can be utilised, not only for community risk assessment, but also for patient management. The Umoona Kidney Project was well accepted by the health service and community members.

Albuminuria in a remote South Australian Aboriginal community: results of a community-based screening program for renal disease.

INTRODUCTION: The poverty, poor environmental living conditions and poor health standards experienced by Aboriginal Australians in some communities in rural and remote Australia have been described recently as 'fourth world'. For more than a century Aboriginal people have suffered the effects of dispossession of their land; destruction of their traditional culture and values; and exposure to infectious diseases, alcohol and the Western diet that is high in fat and sugar. Collectively these factors have contributed to the prevalence of chronic disease that afflicts Aboriginal people. In particular, renal disease has emerged during the last decade as a major contemporary health problem for Aboriginal Australians. According to the latest age- and sex-adjusted figures, Aboriginal people now have approximately nine-fold the risk of non-Aboriginal Australians of developing end-stage renal disease. In parts of Australia's Northern Territory, where Aboriginal people represent over 20% of the Territory's population, the rates of end-stage renal disease have been described as 'epidemic', reaching 2700 per million in the Tiwi Islands. In response to a request from the Umoona Tjutagku Health Service in mid 1997, the Renal Unit at Flinders Medical Centre, Adelaide, South Australia, formed a partnership with the health service to conduct a renal-disease screening program for adult members of the Umoona Community at Coober Pedy, a town 850 kilometres north of Adelaide. The partnership was later expanded to include screening for children (conducted by the Renal Unit at the Women's and Children's Hospital, Adelaide, South Australia). The community named the program 'The Umoona Kidney Project'. The Umoona community had recently experienced the dislocation of a number of its older people who suffered from advanced renal disease and were undergoing dialysis in a variety of centres in South Australia and the Northern Territory. As a result, the community had suffered social trauma. Consistent with the community's overall holistic approach to healthcare, the community wanted the renal program to provide a focus for community awareness of and knowledge about chronic disease, as well as to complement existing health programs. OBJECTIVES: The study objectives were to identify the prevalence of risk factors for renal disease, notably albuminuria, in adults from a remote Aboriginal community, and to examine the association of albuminuria with other risk factors; to empower Aboriginal health workers to self-manage a sustainable, community-controlled renal health program; and to assess the reliability and cultural acceptability of point-of-care technology for detecting renal disease. METHOD: The study was a three-year cross-sectional voluntary adult screening program (The Umoona Kidney Project). The study was performed as a partnership between the Flinders Medical Centre Renal Unit and the Umoona Tjutagku Health Service, and it involved nephrologists, medical scientists, Aboriginal health workers and clinical nurses. SETTING: Umoona Tjutagku Health Service, 850 km north of Adelaide. PARTICIPANTS: 158 adult members of the Umoona community: 58 males (37%; mean age = 43.8 years, range 23-78) and 100 females (63%; mean age = 39.6 years, range 18-72). MAIN OUTCOME MEASURES: First morning urine albumin : creatinine ratio measured by the Bayer DCA 2000 point-of-care analyser machine (Bayer Australia, Melbourne, Australia); lying and standing blood pressure; random blood glucose; body mass index; urinalysis. RESULTS: The study found that of screened adults, 29/149 (19%, 95% C.I. 13%-27%) had persistent microalbuminuria and 13/149 (9%, 95% C.I. 4%-14%) had persistent macroalbuminuria; 62/148 participants (42%, 95% C.I. 34%-50%) had overt hypertension; 35/145 participants (24%, 95% C.I. 17%-32%) had diabetes; 3 participants were newly diagnosed as having non-insulin dependent diabetes; 96/148 participants (65%, 95% C.I. 57%-73%) were either overweight or obese. Strong correlation was observed between the progression of albuminuria and age, all blood pressure categories, blood glucose, body mass index and an increasing number of risk factors. CONCLUSIONS: The Umoona Kidney Project identified a significant community burden of previously unknown incipient and established renal disease that required addressing via clinical- and community-based interventions. The DCA 2000 was a reliable instrument for detecting albuminuria on-site in the remote clinical location and was well accepted by Aboriginal health workers and community participants.

Activation of nuclear factor-kappa B by podocytes in the autologous phase of passive Heymann nephritis.

BACKGROUND: The present study examined whether activation of nuclear factor-kappa B (NF-kappa B) occurs within podocytes in passive Heymann nephritis (PHN) and contributes to the pathogenesis of proteinuria. METHODS: Electrophoretic mobility shift assays (EMSAs) were used to detect NF-kappa B activation, and supershift assays were used to determine the subunits involved. Localization of the activated NF-kappa B subunit p50 was performed by immunohistochemistry. Expression of the NF-kappa B-dependent genes interleukin-1 beta (IL-1 beta) and matrix metalloproteinase-9 (MMP-9) were determined by reverse transcription-polymerase chain reaction and, for IL-1 beta, immunohistochemistry. To inhibit activation of NF-kappa B in vivo, pyrrolidone dithiocarbamate (PDTC) was administered for 10 days following induction of PHN. RESULTS: Glomerular nuclear extracts from rats with PHN showed increased NF-kappa B binding activity in comparison to normal rats. The major Rel/NF-kappa B proteins in these activated complexes were p65 and p50. Immunohistochemistry showed that nuclear translocation of p50 occurred predominantly within podocytes. IL-1 beta mRNA was increased in the PHN rats, and increased IL-1 beta protein was localized predominantly to podocytes by immunohistochemistry. To investigate whether activation of NF-kappa B is involved in the pathogenesis of proteinuria, PDTC was administered to rats with PHN. Electrophoretic mobility shift assays of glomerular nuclear extracts showed a significant reduction in NF-kappa B binding activity in the PDTC-treated rats with a striking reduction in MMP-9 mRNA. Compared with control rats, there was a significant reduction in albuminuria at days 15 (P < 0.001) and 20 (P < 0.001) when PHN was induced with a suboptimal dose of anti-Fx1A antiserum. There was no detectable difference in the systemic immune response to sheep Ig in the treated rats. CONCLUSIONS: These data show that NF-kappa B is activated within podocytes in PHN and suggest that it contributes to autologous phase proteinuria. The critical genes regulated by NF-kappa B in the podocyte have not yet been determined, but may include MMP-9.

Inhibition of heparin-binding epidermal growth factor-like growth factor increases albuminuria in puromycin aminonucleoside nephrosis.

BACKGROUND: Our previous work in the acute puromycin aminonucleoside nephrosis (PAN) model has demonstrated up-regulation of heparin-binding epidermal growth factor-like growth factor (HB-EGF) mRNA and protein within glomerular epithelial cells (GECs) prior to the onset of proteinuria. METHODS: To determine whether increased HB-EGF expression in the acute PAN model contributes to the pathogenesis of proteinuria, a monoclonal antibody (DE10) was produced against recombinant human HB-EGF. RESULTS: The specificity of DE10 for human HB-EGF was confirmed by enzyme-linked immunosorbent assay, immunohistochemical staining, and flow cytometry of transfected cells expressing human and rat HB-EGF, and inhibition of cell proliferation. DE10 also reacted with cells transfected with rat HB-EGF cDNA. Administration of 0.5 mg affinity-purified DE10 to normal rats did not cause significant albuminuria compared with controls. Five days after the induction of the acute PAN model, albuminuria was significantly greater in animals treated with 0.5 mg DE10 than a control mAb (162.6 +/- 32.4 vs. 64.8 +/- 10.2 mg/day, respectively, P < 0.01). Rats treated with DE10 had an earlier onset of severe albuminuria, but no increase in maximal albuminuria at later time points. Electron microscopy showed marked podocyte effacement in both DE10-treated and control animals, but no obvious difference between groups. However, adhesion of the human GEC line 56/10 A1 to laminin and fibronectin, but not to collagens I or IV, was reduced by DE10. CONCLUSIONS: This study suggests that HB-EGF contributes to the integrity of the glomerular filtration barrier, particularly when the podocyte has been injured. Following podocyte injury, adhesion to laminin in the glomerular basement membrane by HB-EGF may be important in reducing albuminuria.

Heparin-binding epidermal growth factor-like growth factor is expressed in the adhesive lesions of experimental focal glomerular sclerosis.

BACKGROUND: In this study, we attempted to determine whether heparin-binding epidermal growth factor-like growth factor (HB-EGF) was up-regulated in two chronic models of proteinuria. METHODS: Chronic passive Heymann nephritis (PHN) and puromycin aminonucleoside (PAN) models were induced in Sprague-Dawley rats. HB-EGF expression was studied by Northern blotting, in situ hybridization, and immunohistochemistry. RESULTS: The chronic PAN model was associated with the development of glomerular lesions of focal glomerular sclerosis (FGS), severe interstitial fibrosis, and renal failure. Lesions of FGS were seen in approximately 80% of glomeruli at all time points, with a slight increase in the number of glomeruli showing extensive adhesion between 40 and 90 days. Northern blots of whole kidney tissue showed a 3- to 5.8-fold increased expression of HB-EGF mRNA in the chronic PAN group. Increased mRNA and protein were localized by in situ hybridization and immunohistochemistry to tubules, glomerular epithelial cells (GECs), and cells of Bowman's capsule. HB-EGF mRNA and protein were strongly expressed by epithelial cells involved in the formation of the lesions of FGS. By contrast, in chronic PHN, there was a small increase in HB-EGF, and the extensive lesions of FGS did not develop despite continued, heavy proteinuria. CONCLUSIONS: These data suggest that HB-EGF may contribute to formation of the lesions of FGS, perhaps through stimulation of abortive mitogenesis in GECs or an adhesive interaction between transmembrane HB-EGF and the exposed glomerular basement membrane.

Heparin-binding EGF-like growth factor mRNA is upregulated in the peri-infarct region of the remnant kidney model: in vitro evidence suggests a regulatory role in myofibroblast transformation.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a potent fibroblast and epithelial cell mitogen that may be important in wound healing. The aim of this study was to determine its distribution and possible function in segmental renal infarction. At day 1 postinfarction, in situ hybridization showed that HB-EGF mRNA was markedly increased by tubular epithelial cells bordering the infarcted zone. At day 3, typical myofibroblasts expressing alpha-smooth muscle actin (alpha-SMA) were present in large numbers at the peri-ischemic border and, over succeeding days, were also seen within the infarcted area. Some of these cells expressed HB-EGF mRNA by in situ hybridization suggesting possible autocrine stimulation. Endothelial cells appeared to be more resistant to ischemia than tubules because some capillaries at the periphery of the infarct, surrounded by infarcted tubules, also expressed HB-EGF mRNA. The staining intensity of HB-EGF mRNA in individual tubules and endothelial cells was maximal at day 5 after infarction, although Northern blots of tissue from the peri-infarct area only showed significantly increased expression of HB-EGF mRNA at days 1 and 3, perhaps reflecting a smaller area of greater intensity of expression at day 5. Because tubular cells expressing high levels of HB-EGF mRNA were directly apposed to myofibroblasts, an attempt was made to determine whether HB-EGF contributed to upregulation of alpha-SMA by human fibroblasts. Although stimulation of the fibroblast cell line MRC-5 with transforming growth factor-beta1 (TGF-beta1) increased alpha-SMA, HB-EGF reduced expression. HB-EGF also strongly inhibited the increased expression of alpha-SMA due to TGF-beta1. Because HB-EGF is a potent fibroblast mitogen and TGF-beta is usually antiproliferative, this study suggests that HB-EGF may contribute to a local balance between fibroblast proliferation and differentiation into myofibroblasts during scarring.

Heparin-binding epidermal growth factor-like growth factor in experimental models of membranous and minimal change nephropathy.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a recently described member of the epidermal growth factor (EGF) family. It binds to heparan sulfate proteoglycans via a cationic domain and is a potent mitogen for epithelial cells, fibroblasts and vascular smooth muscle cells. In the present study we have attempted to identify changes in quantity and distribution of HB-EGF in two models of acute glomerular epithelial cell injury, using Western blotting, immunohistochemistry and in situ hybridization. Prior to disease induction, Western blots showed some expression of HB-EGF protein within glomeruli. Within the first three days in the acute puromycin aminonucleoside (PAN) and passive Heymann nephritis (PHN) models, immunohistochemistry and in situ hybridization demonstrated an up-regulation of HB-EGF mRNA and protein in glomerular epithelial cells (GEC). In both cases, increased protein and mRNA was found prior to the onset of proteinuria and continued until day 21 post-induction, the last time point studied. Early in the course of the models, HB-EGF was localized to the cytoplasm of glomerular epithelial cells. At day 21, however, HB-EGF protein was distributed in a nodular pattern within GEC and along the glomerular basement membrane (GBM) in both models, suggesting that the secreted form might bind to the membrane. The increase in HB-EGF protein within glomeruli was confirmed by Western blots of glomerular membrane protein which, however, demonstrated a single 29 kDa species, consistent with the transmembrane form. These data are not consistent with binding of the secreted form of HB-EGF to the GBM. The transmembrane form of HB-EGF is able to signal in a juxtracrine fashion, so increased expression of HB-EGF mRNA and protein by GEC might contribute to the genesis of proteinuria through the initiation of abortive GEC mitogenesis.

Elevation of human cerebrospinal fluid clusterin concentration is associated with acute neuropathology.

Clusterin is a serum glycoprotein which is an inhibitor of complement and is expressed in many tissues in cell injury and death. It has been identified normal and pathological brain tissue and is a component of normal human cerebrospinal fluid (CSF). We have measured the clusterin concentration of 115 abnormal and normal human CSF samples and related these data to the patient's clinical diagnoses. CSF clusterin levels in patients with neurodegenerative and meningeal disease were within the normal range. Twelve of 15 patients with demyelination, however, had significant elevation of CSF clusterin concentration. This was not a specific finding for multiple sclerosis as elevated clusterin levels were also seen in patients with other acute neuropathology. Determination of CSF clusterin concentration may be of clinical value in neurological diagnosis.