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Lena Succar,1 Ross A Boadle,2 David C Harris,1,3 Gopala K Rangan1,3 1Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, 2Electron Microscopy Laboratory, Institute of Clinical Pathology and Medical Research, Westmead Hospital, 3Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, Sydney, NSW, Australia Purpose: In crescentic glomerulonephritis (CGN), the development of cellular bridges between podocytes and parietal epithelial cells (PECs) triggers glomerular crescent formation. However, the sequential changes in glomerular ultrastructure in CGN are not well defined. This study investigated the time course of glomerular ultrastructure in experimental CGN. Methods: Transmission electron microscopy (TEM) was performed using kidney samples from rats with nephrotoxic serum nephritis (NSN) from day 1 to day 14. Morphometric analysis was conducted on randomly selected glomeruli captured on TEM digital images. Results: On day 1 of NSN, there was widespread formation of focal contacts between the cell bodies of neighboring podocytes, and tight junctions were evident at the site of cell-to-cell contact. This was confirmed by the increased expression of the tight junction molecule, zonula occludens-1 (ZO-1), which localized to the points of podocyte cell–cell body contact. On day 2, the interpodocyte distance decreased and the glomerular basement membrane thickness increased. Foot process effacement (FPE) was segmental on day 3 and diffuse by day 5, accompanied by the formation of podocyte cellular bridges with Bowman’s capsule, as confirmed by a decrease in podocyte-to-PEC distance. Fibrinoid necrosis and cellular crescents were evident in all glomeruli by days 7 and 14. In vitro, the exposure of podocytes to macrophage-conditioned media altered cellular morphology and caused an intracellular redistribution of ZO-1. Conclusion: The formation of tight junctions between podocytes is an early ultrastructural abnormality in CGN, preceding FPE and podocyte bridge formation and occurring in response to inflammatory injury. Podocyte-to-podocyte tight junction formation may be a compensatory mechanism to maintain the integrity of the glomerular filtration barrier following severe endocapillary injury. Keywords: glomerular, crescent, inflammation, zonula occludens

Plasmacytoid dendritic cells play important roles in inducing immune tolerance, preventing allograft rejection, and regulating immune responses in both autoimmune disease and graft-versus-host disease. In order to evaluate a possible protective effect of plasmacytoid dendritic cells against renal inflammation and injury, we purified these cells from mouse spleens and adoptively transferred lipopolysaccharide (LPS)-treated cells, modified ex vivo, into mice with adriamycin nephropathy. These LPS-treated cells localized to the kidney cortex and the lymph nodes draining the kidney, and protected the kidney from injury during adriamycin nephropathy. Glomerulosclerosis, tubular atrophy, interstitial expansion, proteinuria, and creatinine clearance were significantly reduced in mice with adriamycin nephropathy subsequently treated with LPS-activated plasmacytoid dendritic cells as compared to the kidney injury in mice given naive plasmacytoid dendritic cells. In addition, LPS-pretreated cells, but not naive plasmacytoid dendritic cells, convert CD4+CD25- T cells into Foxp3+ regulatory T cells and suppress the proinflammatory cytokine production of endogenous renal macrophages. This may explain their ability to protect against renal injury in adriamycin nephropathy. [ABSTRACT FROM AUTHOR]

Background: With an aging population, the prevalence of hearing loss and dementia are increasing rapidly. Hearing loss is currently considered the largest potentially modifiable risk factor for dementia. The effect of hearing interventions on cognitive function should therefore be investigated, as if effective, these may be successfully implemented to modify cognitive outcomes for older adults with hearing loss., Methods: This prospective longitudinal observational cohort study compared outcomes of a convenience sample of prospectively recruited first-time hearing aid users without dementia from an audiology center with those of community-living older adults participating in a large prospective longitudinal cohort study with/without hearing loss and/or hearing aids. All participants were assessed at baseline, 18 months, and 36 months using the same measures., Results: Participants were 160 audiology clinic patients (48.8% female patient; mean age 73.5 years) with mild-severe hearing loss, fitted with hearing aids at baseline, and 102 participants of the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Aging (AIBL) (55.9% female patient; mean age 74.5 years). 18- and 36-month outcomes of subsets of the first participants to reach these points and complete the cognition assessment to date are compared. Primary comparative analysis showed cognitive stability for the hearing aid group while the AIBL group declined on working memory, visual attention, and psychomotor function. There was a non-significant trend for decline in visual learning for the AIBL group versus no decline for the hearing aid group. The hearing aid group showed significant decline on only 1 subtest and at a significantly slower rate than for the AIBL participants ( p  < 0.05). When education effects on cognitive trajectory were controlled, the HA group still performed significantly better on visual attention and psychomotor function (lower educated participants only) compared to the AIBL group but not on working memory or visual learning. Physical activity had no effect on cognitive performance trajectory., Conclusion: Hearing aid users demonstrated significantly better cognitive performance to 3 years post-fitting, suggesting that hearing intervention may delay cognitive decline/dementia onset in older adults. Further studies using appropriate measures of cognition, hearing, and device use, with longer follow-up, are required., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. JS declared that they were an editorial board member of Frontiers at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Sarant, Busby, Schembri, Fowler and Harris.)

Background: In autosomal dominant polycystic kidney disease (ADPKD) impaired nitric oxide (NO) synthesis, in part, contributes to early-onset hypertension. Beetroot juice (BRJ) reduces blood pressure (BP) by increasing NO-mediated vasodilation. The aim of this double-blind, randomised, placebo-controlled study is to test the hypothesis that BRJ reduces systolic and diastolic clinic BP in hypertensive adults with ADPKD., Methods: Participants with ADPKD and treated hypertension (n = 60) will be randomly allocated (1:1) to receive a daily dose of either nitrate-replete (400 mg nitrate/day) or nitrate-deplete BRJ for 4 weeks. The co-primary outcomes are change in mean systolic and diastolic clinic BP before and after 4 weeks of treatment with daily BRJ. Secondary outcomes are changes in daily home BP, urinary albumin to creatinine ratio, serum and salivary nitrate/nitrite levels and serum asymmetric dimethylarginine levels before and after 4 weeks of BRJ., Discussion: The effect of BRJ in ADPKD has not been previously tested. BRJ is an accessible, natural dietary supplement that, if effective, will provide a novel adjunctive approach for treating hypertension in ADPKD., Trial Registration: ClinicalTrials.gov NCT05401409. Retrospectively registered on 27th May 2022., (© 2023. Crown.)

National strategies for addressing chronic kidney disease (CKD) are crucial to improving kidney health. We sought to describe country-level variations in non-communicable disease (NCD) strategies and CKD-specific policies across different regions and income levels worldwide. The International Society of Nephrology Global Kidney Health Atlas (GKHA) was a multinational cross-sectional survey conducted between July and October 2018. Responses from key opinion leaders in each country regarding national NCD strategies, the presence and scope of CKD-specific policies, and government recognition of CKD as a health priority were described overall and according to region and income level. 160 countries participated in the GKHA survey, comprising 97.8% of the world's population. Seventy-four (47%) countries had an established national NCD strategy, and 53 (34%) countries reported the existence of CKD-specific policies, with substantial variation across regions and income levels. Where CKD-specific policies existed, non-dialysis CKD care was variably addressed. 79 (51%) countries identified government recognition of CKD as a health priority. Low- and low-middle income countries were less likely to have strategies and policies for addressing CKD and have governments which recognise it as a health priority. The existence of CKD-specific policies, and a national NCD strategy more broadly, varied substantially across different regions around the world but was overall suboptimal, with major discrepancies between the burden of CKD in many countries and governmental recognition of CKD as a health priority. Greater recognition of CKD within national health policy is critical to improving kidney healthcare globally., Competing Interests: Outside the submitted work, BLN has received fees for advisory boards, scientific presentations, steering committee roles and travel support from AstraZeneca, Bayer, Boehringer and Ingelheim, and Janssen with all honoraria paid to his institution; AL and serves as a scientific advisor to Boehringer Ingelheim, AstraZeneca, and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); is on the data safety and monitoring board for the NIDDK, Kidney Precision Medicine, University of Washington Kidney Research Institute Scientific Advisory Committee; is funded by the Canadian Institute of Health Research and Kidney Foundation of Canada; PH reports grants from Chiesi Pharmaceuticals; VJ has research grants from Baxter, GSK and reports Consultancy and Advisory Board honoraria from Baxter Healthcare, and AstraZeneca; KK-Z has received honoraria and/or support from Abbott, Abbvie, ACI Clinical (Cara Therapeutics), Akebia, Alexion, Amgen, Ardelyx, ASN (American Society of Nephrology), Astra-Zeneca, Aveo, BBraun, Chugai, Cytokinetics, Daiichi, DaVita, Fresenius, Genentech, GSK, Haymarket Media, Hofstra Medical School, IFKF (International Federation of Kidney Foundations), ISH (International Society of Hemodialysis), International Society of Renal Nutrition & Metabolism (ISRNM), JSDT (Japanese Society of Dialysis Therapy), Hospira, Kabi, Keryx, Kissei, Novartis, Novo-Nordisk, OPKO, NIH (National Institutes of Health), NKF (National Kidney Foundations), Pfizer, Regulus, Relypsa, Resverlogix, Dr Schaer, Sandoz, Sanofi, Shire, VA (Veterans’ Affairs), Takeda, Vifor, UpToDate, ZS-Pharma; PGK reports conference attendance support from Amgen Australia and honorarium from Bayer Australia; SK is Director of the Real World Evidence Consortium that conducts investigator initiated industry funded projects (Allergan, Purdue, GSK, CSL, Lundbeck, NovoNordisk, Jansen, Bayer); CPK has received consulting fees from Abbott, Akebia, Astra-Zeneca, Bayer, Cara Therapeutics, CSL Behring, Rockwell and Vifor; JP reports grants and personal fees from Baxter Healthcare, Fresenius Medical Care, and Davita Healthcare partner; RTK reports personal fees from Baxter; AY-MW reports grants from Sanofi and Otsuka; MHZ has been a consultant or advisory committee member for GSK, AstraZeneca, Roche, and Bayer; KJJ reports personal fees from Fresenius Medical Care; VP has received fees for advisory boards, steering committee roles, or scientific presentations from AbbVie, Astellas, AstraZeneca, Bayer, Baxter, BMS, Boehringer Ingelheim, Dimerix, Durect, Eli Lilly, Gilead, GSK, Janssen, Merck, Mitsubishi Tanabe, Mundipharma, Novartis, Novo Nordisk, Pfizer, Pharmalink, Relypsa, Retrophin, Sanofi, Servier, Tricida, and Vifor. MT reports grants from the Canadian Institutes for Health Research during conduct of the study; DWJ has received consultancy fees, research grants, speaker’s honoraria and travel sponsorships from Baxter Healthcare and Fresenius Medical Care, consultancy fees from Astra Zeneca, Bayer, and AWAK, speaker’s honoraria from ONO and BI & Lilly, and travel sponsorships from Ono and Amgen. He is a current recipient of an Australian National Health and Medical Research Council Leadership Investigator Grant., (Copyright: © 2023 Neuen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

We describe a preliminary effort to model the growth and progression of glioblastoma multiforme, an aggressive form of primary brain cancer, in patients undergoing treatment for recurrence of tumor following initial surgery and chemoradiation. Two reaction-diffusion models are used: the Fisher-Kolmogorov equation and a 2-population model, developed by the authors, that divides the tumor into actively proliferating and quiescent (or necrotic) cells. The models are simulated on 3-dimensional brain geometries derived from magnetic resonance imaging (MRI) scans provided by the Barrow Neurological Institute. The study consists of 17 clinical time intervals across 10 patients that have been followed in detail, each of whom shows significant progression of tumor over a period of 1 to 3 months on sequential follow up scans. A Taguchi sampling design is implemented to estimate the variability of the predicted tumors to using 144 different choices of model parameters. In 9 cases, model parameters can be identified such that the simulated tumor, using both models, contains at least 40 percent of the volume of the observed tumor. We discuss some potential improvements that can be made to the parameterizations of the models and their initialization.

Background: Health information systems (HIS) are fundamental tools for the surveillance of health services, estimation of disease burden and prioritization of health resources. Several gaps in the availability of HIS for kidney disease were highlighted by the first iteration of the Global Kidney Health Atlas., Methods: As part of its second iteration, the International Society of Nephrology conducted a cross-sectional global survey between July and October 2018 to explore the coverage and scope of HIS for kidney disease, with a focus on kidney replacement therapy (KRT)., Results: Out of a total of 182 invited countries, 154 countries responded to questions on HIS (85% response rate). KRT registries were available in almost all high-income countries, but few low-income countries, while registries for non-dialysis chronic kidney disease (CKD) or acute kidney injury (AKI) were rare. Registries in high-income countries tended to be national, in contrast to registries in low-income countries, which often operated at local or regional levels. Although cause of end-stage kidney disease, modality of KRT and source of kidney transplant donors were frequently reported, few countries collected data on patient-reported outcome measures and only half of low-income countries recorded process-based measures. Almost no countries had programs to detect AKI and practices to identify CKD-targeted individuals with diabetes, hypertension and cardiovascular disease, rather than members of high-risk ethnic groups., Conclusions: These findings confirm significant heterogeneity in the global availability of HIS for kidney disease and highlight important gaps in their coverage and scope, especially in low-income countries and across the domains of AKI, non-dialysis CKD, patient-reported outcomes, process-based measures and quality indicators for KRT service delivery., (© The Author(s) 2020. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)

Objectives: The Global Kidney Health Atlas (GKHA) is a multinational, cross-sectional survey designed to assess the current capacity for kidney care across all world regions. The 2017 GKHA involved 125 countries and identified significant gaps in oversight, funding and infrastructure to support care for patients with kidney disease, especially in lower-middle-income countries. Here, we report results from the survey for the second iteration of the GKHA conducted in 2018, which included specific questions about health financing and oversight of end-stage kidney disease (ESKD) care worldwide., Setting: A cross-sectional global survey., Participants: Key stakeholders from 182 countries were invited to participate. Of those, stakeholders from 160 countries participated and were included., Primary Outcomes: Primary outcomes included cost of kidney replacement therapy (KRT), funding for dialysis and transplantation, funding for conservative kidney management, extent of universal health coverage, out-of-pocket costs for KRT, within-country variability in ESKD care delivery and oversight systems for ESKD care. Outcomes were determined from a combination of desk research and input from key stakeholders in participating countries., Results: 160 countries (covering 98% of the world's population) responded to the survey. Economic factors were identified as the top barrier to optimal ESKD care in 99 countries (64%). Full public funding for KRT was more common than for conservative kidney management (43% vs 28%). Among countries that provided at least some public coverage for KRT, 75% covered all citizens. Within-country variation in ESKD care delivery was reported in 40% of countries. Oversight of ESKD care was present in all high-income countries but was absent in 13% of low-income, 3% of lower-middle-income, and 10% of upper-middle-income countries., Conclusion: Significant gaps and variability exist in the public funding and oversight of ESKD care in many countries, particularly for those in low-income and lower-middle-income countries., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Fibrosis is characterized by progressively excessive deposition of matrix components and may lead to organ failure. Transforming growth factor-β (TGF-β) is a key cytokine involved in tissue repair and fibrosis. TGF-β's profibrotic signaling pathways converge at activation of β-catenin. β-Catenin is an important transcription cofactor whose function depends on its binding partner. Promoting β-catenin binding to forkhead box protein O (Foxo) via inhibition of its binding to T-cell factor (TCF) reduces kidney fibrosis in experimental murine models. Herein, we investigated whether β-catenin/Foxo diverts TGF-β signaling from profibrotic to physiological epithelial healing. In an in vitro model of wound healing (scratch assay), and in an in vivo model of kidney injury, unilateral renal ischemia reperfusion, TGF-β treatment in combination with either ICG-001 or iCRT3 (β-catenin/TCF inhibitors) increased β-catenin/Foxo interaction, increased scratch closure by increased cell proliferation and migration, reduced the TGF-β-induced mesenchymal differentiation, and healed the ischemia reperfusion injury with less fibrosis. In addition, administration of ICG-001 or iCRT3 reduced the contractile activity induced by TGF-β in C1.1 cells. Together, our results indicate that redirection of β-catenin binding from TCF to Foxo promotes β-catenin/Foxo-mediated epithelial repair. Targeting β-catenin/Foxo may rebuild normal structure of injured kidney., (Copyright © 2021 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

β-Catenin is an important co-factor which binds multiple transcriptional molecules and mediates fibrogenic signaling pathways. Its role in kidney transplantation is unknown. We quantified binding of β-catenin within renal tubular epithelial cells to transcription factors, TCF1 and FoxO1, using a proximity ligation assay in 240 transplanted kidneys, and evaluated their pathological and clinical outcomes. β-Catenin/FoxO1 binding in 1-month protocol biopsies inversely correlated with contemporaneous chronic fibrosis, subsequent inflammation. and inflammatory fibrosis (P < .001). The relative binding of β-catenin/TCF1 versus β-catenin/FoxO1 (TF ratio) was the optimal biomarker, and abnormal in diverse fibrotic transplant diseases. A high 1-month TF ratio was followed by greater tubular atrophy and interstitial fibrosis scores, cortical inflammation, renal impairment, and proteinuria at 1 year (n = 131, all P < .001). The TF ratio was associated with reduced eGFR (AUC 0.817), mild fibrosis (AUC 0.717), and moderate fibrosis (AUC 0.769) using receiver operating characteristic analysis. An independent validation cohort (n = 76) confirmed 1-month TF was associated with 12-month moderate fibrosis (15.8% vs. 2.6%, P = .047), however, not with other outcomes or 10-year graft survival, which limits generalizabilty of these findings. In summary, differential binding of β-catenin to TCF1 rather than FoxO1 in renal tubular cells was associated with the fibrogenic response in transplanted kidneys., (© 2020 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background and Objectives: People with kidney failure typically receive KRT in the form of dialysis or transplantation. However, studies have suggested that not all patients with kidney failure are best suited for KRT. Additionally, KRT is costly and not always accessible in resource-restricted settings. Conservative kidney management is an alternate kidney failure therapy that focuses on symptom management, psychologic health, spiritual care, and family and social support. Despite the importance of conservative kidney management in kidney failure care, several barriers exist that affect its uptake and quality., Design, Setting, Participants, & Measurements: The Global Kidney Health Atlas is an ongoing initiative of the International Society of Nephrology that aims to monitor and evaluate the status of global kidney care worldwide. This study reports on findings from the 2018 Global Kidney Health Atlas survey, specifically addressing the availability, accessibility, and quality of conservative kidney management., Results: Respondents from 160 countries completed the survey, and 154 answered questions pertaining to conservative kidney management. Of these, 124 (81%) stated that conservative kidney management was available. Accessibility was low worldwide, particularly in low-income countries. Less than half of countries utilized multidisciplinary teams (46%); utilized shared decision making (32%); or provided psychologic, cultural, or spiritual support (36%). One-quarter provided relevant health care providers with training on conservative kidney management delivery., Conclusions: Overall, conservative kidney management is available in most countries; however, it is not optimally accessible or of the highest quality., (Copyright © 2021 by the American Society of Nephrology.)

Background: Residual kidney function (RKF) is associated with improved survival and quality of life in dialysis patients. Previous studies have suggested that initiation of peritoneal dialysis (PD) may slow RKF decline compared to the pre-dialysis period. We sought to evaluate the association between PD initiation and RKF decline in the Initiating Dialysis Early And Late (IDEAL) trial., Methods: In this post hoc analysis of the IDEAL randomized controlled trial, PD participants were included if results from 24-hour urine collections had been recorded within 30 days of dialysis initiation, and at least one value pre- and one value post-dialysis commencement were available. The primary outcome was slope of RKF decline, calculated as mean of urinary creatinine and urea clearances. Secondary outcomes included slope of urine volume decline and time from PD initiation to anuria., Results: The study included 151 participants (79 early start, 72 late start). The slope of RKF decline was slower after PD initiation (-2.69±0.18mL/min/1.73m2/yr) compared to before PD (-4.09±0.33mL/min/1.73m2/yr; change in slope +1.19 mL/min/1.73m2/yr, 95%CI 0.48-1.90, p<0.001). In contrast, urine volume decline was faster after PD commencement (-0.74±0.05 L/yr) compared to beforehand (-0.57±0.06L/yr; change in slope -0.18L/yr, 95%CI -0.34--0.01, p = 0.04). No differences were observed between the early- and late-start groups with respect to RKF decline, urine volume decline or time to anuria., Conclusions: Initiation of PD was associated with a slower decline of RKF compared to the pre-dialysis period., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: YC reports personal fees from Baxter, outside the submitted work. CH reports personal fees from Janssen, GlaxoSmithKline and Osuka, and grant support from Baxter, Fresenius, Shire, PKD Aus and NHMRC, outside the submitted work. MGW has received honorarium for scientific lectures from AstraZeneca, Retrophin, Amgen and Baxter, outside the submitted work. His employer, the George Institute for Global Health, holds research contracts for trials in cardiovascular and/or kidney disease with a range of commercial organizations. DJ reports personal fees from AWAK, Astra-Zeneca, Baxter Healthcare and Fresenius Medical Care, and grant support from Baxter Extramural Grant and Baxter CEC Grant, outside the submitted work. The other authors declare no conflicts of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Type 2 innate lymphoid cells (ILC2s) are a subset of ILCs with critical roles in immunoregulation. However, the possible role of ILC2s as immunotherapy against allograft rejection remains unclear. Here, we show that IL-33 significantly prolonged islet allograft survival. IL-33-treated mice had elevated numbers of ILC2s and regulatory T cells (Tregs). Depletion of Tregs partially abolished the protective effect of IL-33 on allograft survival, and additional ILC2 depletion in Treg-depleted DEREG mice completely abolished the protective effects of IL-33, indicating that ILC2s play critical roles in IL-33-mediated islet graft protection. Two subsets of ILC2s were identified in islet allografts of IL-33-treated mice: IL-10 producing ILC2s (ILC2 10 ) and non-IL-10 producing ILC2s (non-ILC 10 ). Intravenous transfer of ILC2 10 cells, but not non-ILC 10 , prolonged islet allograft survival in an IL-10-dependent manner. Locally transferred ILC2 10 cells led to long-term islet graft survival, suggesting that ILC2 10 cells are required within the allograft for maximal suppressive effect and graft protection. This study has uncovered a major protective role of ILC2 10 in islet transplantation which could be potentiated as a therapeutic strategy., (© 2020 The Authors. Published under the terms of the CC BY 4.0 license.)

Transforming growth factor β (TGF-β) is the key cytokine involved in causing fibrosis through cross-talk with major profibrotic pathways. However, inhibition of TGF-β to prevent fibrosis would also abrogate its anti-inflammatory and wound-healing effects. β-catenin is a common co-factor in most TGF-β signaling pathways. β-catenin binds to T-cell factor (TCF) to activate profibrotic genes and binds to Forkhead box O (Foxo) to promote cell survival under oxidative stress. Using a proximity ligation assay in human kidney biopsies, we found that β-catenin/Foxo interactions were higher in kidney with little fibrosis, whereas β-catenin/TCF interactions were upregulated in the kidney of patients with fibrosis. We hypothesised that β-catenin/Foxo is protective against kidney fibrosis. We found that Foxo1 protected against rhTGF-β1-induced profibrotic protein expression using a CRISPR/cas9 knockout of Foxo1 or TCF1 in murine kidney tubular epithelial C1.1 cells. Co-administration of TGF-β with a small molecule inhibitor of β-catenin/TCF (ICG-001), protected against kidney fibrosis in unilateral ureteral obstruction. Collectively, our human, animal and in vitro findings suggest β-catenin/Foxo as a therapeutic target in kidney fibrosis.

Previous studies demonstrated that the 52-kDa FK506-binding protein (FKBP52) proline-rich loop is functionally relevant in the regulation of steroid hormone receptor activity. While zebra fish ( Danio rerio; Dr ) FKBP52 contains all of the analogous domains and residues previously identified as critical for FKBP52 potentiation of receptor activity, it fails to potentiate activity. Thus, we used a cross-species comparative approach to assess the residues that are functionally critical for FKBP52 function. Random selection of gain-of-function DrFKBP52 mutants in Saccharomyces cerevisiae identified two critical residues, alanine 111 (A111) and threonine 157 (T157), for activation of receptor potentiation by DrFKBP52. In silico homology modeling suggests that alanine to valine substitution at position 111 in DrFKBP52 induces an open conformation of the proline-rich loop surface similar to that observed on human FKBP52, which may allow for sufficient surface area and increased hydrophobicity for interactions within the receptor-chaperone complex. A second mutation in the FKBP12-like domain 2 (FK2), threonine 157 to arginine (T157R), also enhanced potentiation, and the DrFKBP52-A111V/T157R double mutant potentiated receptor activity similar to human FKBP52. Collectively, these results confirm the functional importance of the FKBP52 proline-rich loop, suggest that an open conformation on the proline-rich loop surface is a predictor of activity, and highlight the importance of an additional residue within the FK2 domain.

Escherichia coli strain 15 (ATCC 9723) formed robust biofilms of two distinct forms on glass tubes. In rich, low-osmolarity medium, the biofilms were restricted to the air/liquid interface, resulting in rings attached to the glass. As it was not evident that these biofilms extended across the liquid surface, we termed them 'ring' rather than 'pellicle' biofilms. In minimal medium supplemented with a non-fermentable substrate as the carbon/energy source, we observed either robust ring biofilms or little biofilm of any type, depending on the substrate. In contrast, fermentable substrates (sugars and sugar derivatives) supported robust biofilms covering most of the solid/liquid interface, which we termed 'tube-covering biofilms'. Maximal biofilm growth was observed when the sugar was a relatively poor substrate, supporting slow growth and known to cause minimal dephosphorylation of regulatory protein Enzyme IIA Glucose of the phosphotransferase system. Compounds found to be inhibitors of biofilm growth, such as lactate, caused a shift from tube-covering to ring form at low concentration and complete loss of biofilm growth at high when added to minimal medium supplemented with a fermentable substrate. Exogenous cAMP activated biofilm growth under all conditions tested, leading to more intense ring or tube-covering biofilms and/or to a shift from ring to tube-covering form.

The occurrence of a spontaneous nephropathy with intranuclear inclusions in laboratory mice has puzzled pathologists for over 4 decades, because its etiology remains elusive. The condition is more severe in immunodeficient animals, suggesting an infectious cause. Using metagenomics, we identify the causative agent as an atypical virus, termed "mouse kidney parvovirus" (MKPV), belonging to a divergent genus of Parvoviridae. MKPV was identified in animal facilities in Australia and North America, is transmitted via a fecal-oral or urinary-oral route, and is controlled by the adaptive immune system. Detailed analysis of the clinical course and histopathological features demonstrated a stepwise progression of pathology ranging from sporadic tubular inclusions to tubular degeneration and interstitial fibrosis and culminating in renal failure. In summary, we identify a widely distributed pathogen in laboratory mice and establish MKPV-induced nephropathy as a new tool for elucidating mechanisms of tubulointerstitial fibrosis that shares molecular features with chronic kidney disease in humans., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Regulatory T cells (T regs ) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of T regs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of T regs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of T regs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2-interacting mediator (Bim) knock-out mice by transient depleting T regs . Bim is a pro-apoptotic member of the B cell lymphoma 2 (Bcl-2) family. Bim knock-out (Bim -/- ) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that T reg depletion in Bim -/- mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild-type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17α, interferon (IFN)-γ and tumour necrosis factor (TNF)-α were increased significantly after T reg depletion in Bim -/- mice. This study demonstrates that transient depletion of T regs leads to enhanced self-reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim-deficient mice., (© 2017 British Society for Immunology.)

We aimed to assess the association between dairy product consumption and calcium intake with the prevalence and 10-year incidence of chronic kidney disease (CKD). 1185 participants aged ≥50 years at baseline were examined between 1992-4 and 2002-4. Dietary data were collected using a food frequency questionnaire, and servings of dairy food consumption were calculated. Baseline biochemistry including serum creatinine was measured. CKD was defined as Modification of Diet in Renal Disease Study estimated glomerular filtration rate <60 mL·min -1. 1.73 m -2 . Cross-sectional analysis showed that older adults in the highest quintile compared to the lowest quintile (reference group) of low/reduced fat dairy food consumption had reduced odds of CKD, multivariable-adjusted odds ratio, OR, 0.64 (95% confidence intervals, CI, 0.43-0.96). Increasing total intake of dietary calcium was associated with reduced odds of CKD (P-trend = 0.02); comparing highest versus lowest quintile: OR 0.62 (95% CI 0.42-0.92). Participants in the second versus first quintile of low/reduced fat dairy food consumption at baseline had 49% reduced risk of CKD 10 years later, OR 0.51 (95% CI 0.29-0.89). Higher consumption of low/reduced fat dairy foods was independently associated with lower risk of CKD. Additional population-based studies are warranted to confirm these findings.

Regulatory T cells (Tregs) have been shown to be important in maintaining immune homeostasis and preventing autoimmune disease, including autoimmune kidney disease. It is also likely that they play a role in limiting kidney transplant rejection and potentially in promoting transplant tolerance. Although other subsets of Tregs exist, the most potent and well-defined Tregs are the Foxp3 expressing CD4(+) Tregs derived from the thymus or generated peripherally. These CD4(+)Foxp3(+) Tregs limit autoimmune renal disease in animal models, especially chronic kidney disease, and kidney transplantation. Furthermore, other subsets of Tregs, including CD8 Tregs, may play a role in immunosuppression in kidney disease. The development and protective mechanisms of Tregs in kidney disease and kidney transplantation involve multiple mechanisms of suppression. Here we review the development and function of CD4(+)Foxp3(+) Tregs. We discuss the specific application of Tregs as a therapeutic strategy to prevent kidney disease and to limit kidney transplant rejection and detail clinical trials in this area of transplantation., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

CD103(+) dendritic cells (DCs) in nonlymphoid organs exhibit two main functions: maintaining tolerance by induction of regulatory T cells and protecting against tissue infection through cross-presentation of foreign antigens to CD8(+) T cells. However, the role of CD103(+) DCs in kidney disease is unknown. In this study, we show that CD103(+) DCs are one of four subpopulations of renal mononuclear phagocytes in normal kidneys. CD103(+) DCs expressed DC-specific surface markers, transcription factors, and growth factor receptors and were found in the kidney cortex but not in the medulla. The number of kidney CD103(+) DCs was significantly higher in mice with adriamycin nephropathy (AN) than in normal mice, and depletion of CD103(+) DCs attenuated kidney injury in AN mice. In vitro, kidney CD103(+) DCs preferentially primed CD8(+) T cells and did not directly induce tubular epithelial cell apoptosis. Adoptive transfer of CD8(+) T cells significantly exacerbated kidney injury in AN SCID mice, whereas depletion of CD103(+) DCs in these mice impaired activation and proliferation of transfused CD8(+) T cells and prevented the exacerbation of kidney injury associated with this transfusion. In conclusion, kidney CD103(+) DCs display a pathogenic role in murine CKD via activation of CD8(+) T cells., (Copyright © 2016 by the American Society of Nephrology.)

Background: Endothelial-mesenchymal transition (EndoMT) is a major source of myofibroblast formation in kidney fibrosis. Our previous study showed a profibrotic role for matrix metalloproteinase 9 (MMP-9) in kidney fibrosis via induction of epithelial-mesenchymal transition (EMT). Inhibition of MMP-9 activity reduced kidney fibrosis in murine unilateral ureteral obstruction. This study investigated whether MMP-9 also plays a role in EndoMT in human glomerular endothelial cells., Results: TGF-β1 (10 or 20 ng/ml) induced EndoMT in HKGECs as shown by morphological changes. In addition, VE-cadherin and CD31 were significantly downregulated, whereas α-SMA, vimentin, and N-cadherin were upregulated. RT-PCR revealed that Snail, a known inducer of EMT, was upregulated. The MMP inhibitor GM6001 abrogated TGF-β1-induced EndoMT. Zymography indicated that MMP-9 was also upregulated in TGF-β1-treated HKGECs. Recombinant MMP-9 (2 μg/ml) induced EndoMT in HKGECs via Notch signaling, as evidenced by increased formation of the Notch intracellular domain (NICD) and decreased Notch 1. Inhibition of MMP-9 activity by its inhibitor showed a dose-dependent response in preventing TGF-β1-induced α-SMA and NICD in HKGECs, whereas inhibition of Notch signaling by γ-secretase inhibitor (GSI) blocked rMMP-9-induced EndoMT., Conclusions: Taken together, our results demonstrate that MMP-9 plays an important role in TGF-β1-induced EndoMT via upregulation of Notch signaling in HKGECs.

Background: CD166, an adhesion molecule of the immunoglobulin superfamily, is one of the crucial effectors that traffic lymphocytes into tissues. Till now, the expression and role of CD166 in the chronic kidney disease remains unknown., Objectives: In the present study, we are to examine the expression of CD166 in the chronic kidney disease, and to explore its function with CD4+ T cells., Materials and Methods: CD166 expression was tested by Flow Cytometry (FACS) in the primary macrophages stimulated with LPS. In vivo, the expression of CD166 and CD4 were examined in the kidney tissues of adriamycin-induced nephropathy (AN) mice by immnohistochemistry. Macrophages and lymphocytes were co-cultured, the interaction between CD166 and CD4 was tested by immunofluorescent staining. Furthermore, the effects of CD166 on the activation and proliferation of T cells were explored., Results: In this study, CD166 expression was found to be upregulated on activated macrophages and glomerular endothelia in the adriamycin-induced nephropathy (AN) mice and CD4+ T cells were increased with CD166 expression in the AN mice. The interaction between macrophages and CD4+ T cells indicated that CD166 played a key role in the recruitment of lymphocytes in the chronic kidney disease, and neither proliferation nor activation of T cells was affected by CD166., Conclusions: CD166 expressed on macrophages and endothelia in AN kidney, and the function was related to the recruitment of CD4+ T cells into inflamed kidney, indicating that CD166 may be a potential target for reducing the inflammatory infiltrates in the chronic kidney disease.

Macrophages are found in normal kidney and in increased numbers in diseased kidney, where they act as key players in renal injury, inflammation, and fibrosis. Macrophages are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics in response to various stimuli in the local microenvironment in different types of kidney disease. In kidney tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce pro-inflammatory macrophages, which contribute to further tissue injury, inflammation, and subsequent fibrosis. Apoptotic cells and anti-inflammatory factors in post-inflammatory tissues induced anti-inflammatory macrophages, which can mediate kidney repair and regeneration. This review summarizes the role of macrophages with different phenotypes in kidney injury, inflammation, and fibrosis in various acute and chronic kidney diseases. Understanding alterations of kidney microenvironment and the factors that control the phenotype and functions of macrophages may offer an avenue for the development of new cellular and cytokine/growth factor-based therapies as alternative treatment options for patients with kidney disease., (©2015 Int. Union Physiol. Sci./Am. Physiol. Soc.)

Conventional markers of macrophages (Mфs) and dendritic cells (DCs) lack specificity and often overlap, leading to confusion and controversy regarding the precise function of these cells in kidney and other diseases. This study aimed to identify the phenotype and function of renal mononuclear phagocytes (rMPs) expressing key markers of both Mфs and DCs. F4/80(+)CD11c(+) cells accounted for 45% of total rMPs in normal kidneys and in those from mice with Adriamycin nephropathy (AN). Despite expression of the DC marker CD11c, these double-positive rMPs displayed the features of Mфs, including Mф-like morphology, high expression of CD68, CD204, and CD206, and high phagocytic ability but low antigen-presenting ability. F4/80(+)CD11c(+) cells were found in the cortex but not in the medulla of the kidney. In AN, F4/80(+)CD11c(+) cells displayed an M1 Mф phenotype with high expression of inflammatory mediators and costimulatory factors. Adoptive transfer of F4/80(+)CD11c(+) cells separated from diseased kidney aggravated renal injury in AN mice. Furthermore, adoptive transfer of common progenitors revealed that kidney F4/80(+)CD11c(+) cells were derived predominantly from monocytes, but not from pre-DCs. In conclusion, renal F4/80(+)CD11c(+) cells are a major subset of rMPs and display Mф-like phenotypic and functional characteristics in health and in AN., (Copyright © 2015 by the American Society of Nephrology.)

Heterocyclic dithiocarbamates have anti-inflammatory and anti-proliferative effects in rodent models of chronic kidney disease. In this study, we tested the hypothesis that pyrrolidine dithiocarbamate (PDTC) reduces the progression of polycystic kidney disease (PKD). Male Lewis polycystic kidney (LPK) rats (an ortholog of Nek8/NPHP9) received intraperitoneal injections of either saline vehicle or PDTC (40 mg/kg once or twice daily) from postnatal weeks 4 until 11. By serial magnetic resonance imaging at weeks 5 and 10, the relative within-rat increase in total kidney volume and cyst volume were 1.3-fold (P = 0.01) and 1.4-fold (P < 0.01) greater, respectively, in LPK + Vehicle compared to the LPK + PDTC(40 mg/kg twice daily) group. At week 11 in LPK rats, PDTC attenuated the increase in kidney weight to body weight ratio by 25% (P < 0.01) and proteinuria by 66% (P < 0.05 vs. LPK + Vehicle) but did not improve renal dysfunction. By quantitative whole-slide image analysis, PDTC did not alter interstitial CD68+ cell accumulation, interstitial fibrosis, or renal cell proliferation in LPK rats at week 11. The phosphorylated form of the nuclear factor (NF)-κB subunit, p105, was increased in cystic epithelial cells of LPK rats, but was not altered by PDTC. Moreover, PDTC did not significantly alter nuclear expression of the p50 subunit or NF-κB (p65)-DNA binding. Kidney enlargement in LPK rats was resistant to chronic treatment with a proteasome inhibitor, bortezomib. In conclusion, PDTC reduced renal cystic enlargement and proteinuria but lacked anti-inflammatory effects in LPK rats., (© 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.)

Background: Endothelial-mesenchymal transition (EndoMT) has been shown to be a major source of myofibroblasts, contributing to kidney fibrosis. However, in vitro study of endothelial cells often relies on culture of isolated primary endothelial cells due to the unavailability of endothelial cell lines. Our recent study suggested that peritubular endothelial cells could contribute to kidney fibrosis through EndoMT. Therefore, successful isolation and culture of mouse peritubular endothelial cells could provide a new platform for studying kidney fibrosis. This study describes an immunomagnetic separation method for the isolation of mouse renal peritubular endothelial cells using anti-CD146 MicroBeads, followed by co-culture with mouse renal proximal tubular epithelial cells to maintain endothelial phenotype., Results: Flow cytometry showed that after isolation and two days of culture, about 95% of cells were positive for endothelial-specific marker CD146. The percentage of other cells, including dendritic cells (CD11c) and macrophages (F4/80), was less than 1%. Maintenance of endothelial cell phenotype required vascular endothelial growth factor (VEGF) and co-culture with mouse proximal tubular epithelial cells., Conclusion: In this study, we established a method for the isolation of mouse renal peritubular endothelial cells by using immunomagnetic separation with anti-CD146 MicroBeads, followed by co-culture with mouse renal proximal tubular epithelial cells to maintain phenotype.

Steroid hormone receptors are ligand-dependent transcription factors that require the ordered assembly of multichaperone complexes for transcriptional activity. Although heat shock protein (Hsp) 90 and Hsp70 are key players in this process, multiple Hsp70- and Hsp90-associated cochaperones associate with receptor-chaperone complexes to regulate receptor folding and activation. Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA) was recently characterized as an Hsp70 and Hsp90-associated cochaperone that specifically regulates androgen receptor activity. However, the specificity of SGTA for additional members of the steroid hormone receptor superfamily and the mechanism by which SGTA regulates receptor activity remain unclear. Here we report that SGTA associates with and specifically regulates the androgen, glucocorticoid, and progesterone receptors and has no effect on the mineralocorticoid and estrogen receptors in both yeast and mammalian cell-based reporter assays. In both systems, SGTA knockdown/deletion enhances receptor activity, whereas SGTA overexpression suppresses receptor activity. We demonstrate that SGTA binds directly to Hsp70 and Hsp90 in vitro with similar affinities yet predominately precipitates with Hsp70 from cell lysates, suggesting a role for SGTA in early, Hsp70-mediated folding. Furthermore, SGTA expression completely abrogates the regulation of receptor function by FKBP52 (52-kDa FK506-binding protein), which acts at a later stage of the chaperone cycle. Taken together, our data suggest a role for SGTA at distinct steps in the chaperone-dependent modulation of androgen, glucocorticoid, and progesterone receptor activity., (© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.)

Alternatively activated macrophages (M2) regulate immune responses and ex vivo polarized splenic M2 are able to ameliorate renal injury including models of renal disease, such as adriamycin nephropathy. Whether M2 derived from other organs have similar protective efficacy is unknown. Here, we report adoptively transferred bone marrow M2 macrophages did not improve renal function or reduce renal injury in adriamycin nephropathy, whereas splenic M2 macrophages were protective. Bone marrow and splenic M2 macrophages showed similar regulatory phenotypes and suppressive functions in vitro. Within the inflamed kidney, suppressive phenotypes in bone marrow but not in splenic M2 macrophages, were dramatically reduced. Loss of the suppressive phenotype in bone marrow M2 was related to strong proliferation of bone marrow M2. Bone marrow M2 proliferation in vivo correlated with M-CSF expression by tubular cells in the inflamed kidney. Inhibition of M-CSF in vitro limited bone marrow M2 proliferation and prevented switch of phenotype. Proliferating cells derived from transfused bone marrow M2 were inflammatory rather than regulatory in their phenotype and function. Thus bone marrow in contrast to splenic M2 macrophages do not protect against renal structural and functional injury in murine adriamycin nephropathy. The failed renoprotection of bone marrow M2 is due to the switch of transfused M2 macrophages from a regulatory to an inflammatory phenotype.

Background: Non-randomized studies suggest an association between serum uric acid levels and progression of chronic kidney disease (CKD). The aim of this systematic review is to summarize evidence from randomized controlled trials (RCTs) concerning the benefits and risks of uric acid-lowering therapy on renal outcomes., Methods: Medline, Excerpta Medical Database and Cochrane Central Register of Controlled Trials were searched with English language restriction for RCTs comparing the effect of uric acid-lowering therapy with placebo/no treatment on renal outcomes. Treatment effects were summarized using random-effects meta-analysis., Results: Eight trials (476 participants) evaluating allopurinol treatment were eligible for inclusion. There was substantial heterogeneity in baseline kidney function, cause of CKD and duration of follow-up across these studies. In five trials, there was no significant difference in change in glomerular filtration rate from baseline between the allopurinol and control arms [mean difference (MD) 3.1 mL/min/1.73 m2, 95% confidence intervals (CI) -0.9, 7.1; heterogeneity χ2=1.9, I2=0%, P=0.75]. In three trials, allopurinol treatment abrogated increases in serum creatinine from baseline (MD -0.4 mg/dL, 95% CI -0.8, -0.0 mg/dL; heterogeneity χ2=3, I2=34%, P=0.22). Allopurinol had no effect on proteinuria and blood pressure. Data for effects of allopurinol therapy on progression to end-stage kidney disease and death were scant. Allopurinol had uncertain effects on the risks of adverse events., Conclusions: Uric acid-lowering therapy with allopurinol may retard the progression of CKD. However, adequately powered randomized trials are required to evaluate the benefits and risks of uric acid-lowering therapy in CKD.

Background and Objectives: The Initiating Dialysis Early and Late study showed that planned early or late initiation of dialysis, based on the Cockcroft and Gault estimation of GFR, was associated with identical clinical outcomes. This study examined the association of all-cause mortality with estimated GFR at dialysis commencement, which was determined using multiple formulas., Design, Setting, Participants, & Measurements: Initiating Dialysis Early and Late trial participants were stratified into tertiles according to the estimated GFR measured by Cockcroft and Gault, Modification of Diet in Renal Disease, or Chronic Kidney Disease-Epidemiology Collaboration formula at dialysis commencement. Patient survival was determined using multivariable Cox proportional hazards model regression., Results: Only Initiating Dialysis Early and Late trial participants who commenced on dialysis were included in this study (n=768). A total of 275 patients died during the study. After adjustment for age, sex, racial origin, body mass index, diabetes, and cardiovascular disease, no significant differences in survival were observed between estimated GFR tertiles determined by Cockcroft and Gault (lowest tertile adjusted hazard ratio, 1.11; 95% confidence interval, 0.82 to 1.49; middle tertile hazard ratio, 1.29; 95% confidence interval, 0.96 to 1.74; highest tertile reference), Modification of Diet in Renal Disease (lowest tertile hazard ratio, 0.88; 95% confidence interval, 0.63 to 1.24; middle tertile hazard ratio, 1.20; 95% confidence interval, 0.90 to 1.61; highest tertile reference), and Chronic Kidney Disease-Epidemiology Collaboration equations (lowest tertile hazard ratio, 0.93; 95% confidence interval, 0.67 to 1.27; middle tertile hazard ratio, 1.15; 95% confidence interval, 0.86 to 1.54; highest tertile reference)., Conclusion: Estimated GFR at dialysis commencement was not significantly associated with patient survival, regardless of the formula used. However, a clinically important association cannot be excluded, because observed confidence intervals were wide.

Two types of alternatively activated macrophages, M(2a) induced by IL-4/IL-13 and M(2c) by IL-10/TGF-β, exhibit anti-inflammatory functions in vitro and protect against renal injury in vivo. Since their relative therapeutic efficacy is unclear, we compared the effects of these two macrophage subsets in murine adriamycin nephrosis. Both subsets significantly reduced renal inflammation and renal injury; however, M(2c) macrophages more effectively reduced glomerulosclerosis, tubular atrophy, interstitial expansion, and proteinuria than M(2a) macrophages. The M(2c) macrophages were also more effective than M(2a) in reduction of macrophage and CD4(+) T-cell infiltration in kidney. Moreover, nephrotic mice treated with M(2c) had a greater reduction in renal fibrosis than those treated with M(2a). M(2c) but not M(2a) macrophages induced regulatory T cells (Tregs) from CD4(+)CD25(-) T cells in vitro, and increased Treg numbers in local draining lymph nodes of nephrotic mice. To determine whether the greater protection with M(2c) was due to their capability to induce Tregs, the Tregs were depleted by PC61 antibody in nephrotic mice treated with M(2a) or M(2c). Treg depletion diminished the superior effects of M(2c) compared to M(2a) in protection against renal injury, inflammatory infiltrates, and renal fibrosis. Thus, M(2c) are more potent than M(2a) macrophages in protecting against renal injury due to their ability to induce Tregs.

Increasing evidence indicates that vitamin D deficiency exacerbates chronic kidney injury, but its effects on renal enlargement in polycystic kidney disease (PKD) are not known. In this study, male Lewis polycystic kidney disease (LPK) rats received a normal diet (ND; AIN-93G) supplemented with or without cholecalciferol (vitamin D-deficient diet, VDD; both 0.5% calcium), commenced at either postnatal week 3 (until weeks 10-20; study 1) or from week 10 (until week 20; study 2). Levels of 25-hydroxy vitamin D were reduced in groups receiving the VDD (12 ± 1 nmol/l vs. 116 ± 5 in ND; P < 0.001). In study 1, food intake and weight gain increased by ∼25% in LPK rats receiving the VDD ad libitum, and at week 20 this was associated with a mild reduction in the corrected serum calcium (SCa(2+), 7.4%) and TKW:BW ratio (8.8%), and exacerbation of proteinuria (87%) and hypertension (19%; all P < 0.05 vs. ND). When LPK rats were pair-fed for weeks 3-10, there was a further reduction in the SCa(2+) (25%) and TKW:BW ratio (22%) in the VDD group (P < 0.05 vs. ND). In study 2, the VDD did not alter food intake and body weight, reduced SCa(2+) (7.7%), worsened proteinuria (41.9%), interstitial monocyte accumulation (26.4%), renal dysfunction (21.4%), and cardiac enlargement (13.2%, all P < 0.05), but there was a trend for a reduction in the TKW:BW ratio (13%, P = 0.09). These data suggest that chronic vitamin D deficiency has adverse long-term actions on proteinuria, interstitial inflammation, renal function, and cardiovascular disease in PKD, and these negate its mild inhibitory effect on kidney enlargement.

Macrophages (MΦ) are located throughout kidney tissue, where they play important roles in homeostasis, surveillance, tolerance, and cytoprotection. MΦ are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics depending on their microenvironment and the disease type and stage. Recent studies have identified a dual role for MΦ in several murine models of kidney disease. In this review, we discuss the pathogenic and protective roles of the various MΦ subsets in experimental and human kidney diseases and summarize current progress toward the therapeutic use of MΦ in kidney diseases.

A pro-fibrotic role of matrix metalloproteinase-9 (MMP-9) in tubular cell epithelial-mesenchymal transition (EMT) is well established in renal fibrosis; however studies from our group and others have demonstrated some previously unrecognized complexity of MMP-9 that has been overlooked in renal fibrosis. Therefore, the aim of this study was to determine the expression pattern, origin and the exact mechanism underlying the contribution of MMP-9 to unilateral ureteral obstruction (UUO), a well-established model of renal fibrosis via MMP-9 inhibition. Renal MMP-9 expression in BALB/c mice with UUO was examined on day 1, 3, 5, 7, 9, 11 and 14. To inhibit MMP-9 activity, MMP-2/9 inhibitor or MMP-9-neutralizing antibody was administered daily for 4 consecutive days from day 0-3, 6-9 or 10-13 and tissues harvested at day 14. In UUO, there was a bi-phasic early- and late-stage upregulation of MMP-9 activity. Interestingly, tubular epithelial cells (TECs) were the predominant source of MMP-9 during early stage, whereas TECs, macrophages and myofibroblasts produced MMP-9 during late-stage UUO. Early- and late-stage inhibition of MMP-9 in UUO mice significantly reduced tubular cell EMT and renal fibrosis. Moreover, MMP-9 inhibition caused a significant reduction in MMP-9-cleaved osteopontin and macrophage infiltration in UUO kidney. Our in vitro study showed MMP-9-cleaved osteopontin enhanced macrophage transwell migration and MMP-9 of both primary TEC and macrophage induced tubular cell EMT. In summary, our result suggests that MMP-9 of both TEC and macrophage origin may directly or indirectly contribute to the pathogenesis of renal fibrosis via osteopontin cleavage, which, in turn further recruit macrophage and induce tubular cell EMT. Our study also highlights the time dependency of its expression and the potential of stage-specific inhibition strategy against renal fibrosis.

The CD40-CD154 costimulatory pathway has been shown to be critical for both T- and B-cell activation in autoimmune disease. Here, we assessed the effects of blocking this pathway using CD40 DNA vaccine enhanced by dendritic cell targeting on the development of active Heymann nephritis, a rat model of human membranous nephropathy. DNA vaccination delivers plasmid DNA encoding the target antigen, either alone or in combination with enhancing elements, to induce both humoral and cellular immune responses. To determine whether CD40 DNA vaccine targeting the encoded CD40 directly to dendritic cells would improve the efficacy of the vaccination against self-protein CD40, we utilized a plasmid encoding a single-chain Fv antibody specific for the dendritic cell-restricted antigen-uptake receptor DEC205 (scDEC), the target gene CD40, and the adjuvant tetanus sequence p30. This vaccine plasmid was compared to a control plasmid without scDEC. Rats vaccinated with scDEC-CD40 had significantly less proteinuria and renal injury than did rats receiving scControl-CD40 and were protected from developing Heymann nephritis. Thus, CD40 DNA vaccination targeted to dendritic cells limits the development of Heymann nephritis.

Transforming growth factor β1 (TGF-β1) is known to be both anti-inflammatory and profibrotic. Cross-talk between TGF-β/Smad and Wnt/β-catenin pathways in epithelial-mesenchymal transition (EMT) suggests a specific role for β-catenin in profibrotic effects of TGF-β1. However, no such mechanistic role has been demonstrated for β-catenin in the anti-inflammatory effects of TGF-β1. In the present study, we explored the role of β-catenin in the profibrotic and anti-inflammatory effects of TGF-β1 by using a cytosolic, but not membrane, β-catenin knockdown chimera (F-TrCP-Ecad) and the β-catenin/CBP inhibitor ICG-001. TGF-β1 induced nuclear Smad3/β-catenin complex, but not β-catenin/LEF-1 complex or TOP-flash activity, during EMT of C1.1 (renal tubular epithelial) cells. F-TrCP-Ecad selectively degraded TGF-β1-induced cytoplasmic β-catenin and blocked EMT of C1.1 cells. Both F-TrCP-Ecad and ICG-001 blocked TGF-β1-induced Smad3/β-catenin and Smad reporter activity in C1.1 cells, suggesting that TGF-β1-induced EMT depends on β-catenin binding to Smad3, but not LEF-1 downstream of Smad3, through canonical Wnt. In contrast, in J774 macrophages, the β-catenin level was low and was not changed by interferon-γ (IFN-γ) or lipopolysaccharide (LPS) with or without TGF-β1. TGF-β1 inhibition of LPS-induced TNF-α and IFN-γ-stimulated inducible NO synthase (iNOS) expression was not affected by F-TrCP-Ecad, ICG-001 or by overexpression of wild-type β-catenin in J774 cells. Inhibition of β-catenin by either F-TrCP-Ecad or ICG-001 abolished LiCl-induced TOP-flash, but not TGF-β1-induced Smad reporter, activity in J774 cells. These results demonstrate for the first time that β-catenin is required as a co-factor of Smad in TGF-β1-induced EMT of C1.1 epithelial cells, but not in TGF-β1 inhibition of macrophage activation. Targeting β-catenin may dissociate the TGF-β1 profibrotic and anti-inflammatory effects.

Background: Since the mid-1990s, early dialysis initiation has dramatically increased in many countries. The Initiating Dialysis Early and Late (IDEAL) study demonstrated that, compared with late initiation, planned early initiation of dialysis was associated with comparable clinical outcomes and increased health care costs. Because residual renal function is a key determinant of outcome and is better preserved with peritoneal dialysis (PD), the present pre-specified subgroup analysis of the IDEAL trial examined the effects of early-compared with late-start dialysis on clinical outcomes in patients whose planned therapy at the time of randomization was PD., Methods: Adults with an estimated glomerular filtration rate (eGFR) of 10 - 15 mL/min/1.73 m(2) who planned to be treated with PD were randomly allocated to commence dialysis at an eGFR of 10 - 14 mL/min/1.73 m(2) (early start) or 5 - 7 mL/min/1.73 m(2) (late start). The primary outcome was all-cause mortality., Results: Of the 828 IDEAL trial participants, 466 (56%) planned to commence PD and were randomized to early start (n = 233) or late start (n = 233). The median times from randomization to dialysis initiation were, respectively, 2.03 months [interquartile range (IQR):1.67 - 2.30 months] and 7.83 months (IQR: 5.83 - 8.83 months). Death occurred in 102 early-start patients and 96 late-start patients [hazard ratio: 1.04; 95% confidence interval (CI): 0.79 - 1.37]. No differences in composite cardiovascular events, composite infectious deaths, or dialysis-associated complications were observed between the groups. Peritonitis rates were 0.73 episodes (95% CI: 0.65 - 0.82 episodes) per patient-year in the early-start group and 0.69 episodes (95% CI: 0.61 - 0.78 episodes) per patient-year in the late-start group (incidence rate ratio: 1.19; 95% CI: 0.86 - 1.65; p = 0.29). The proportion of patients planning to commence PD who actually initiated dialysis with PD was higher in the early-start group (80% vs 70%, p = 0.01)., Conclusion: Early initiation of dialysis in patients with stage 5 chronic kidney disease who planned to be treated with PD was associated with clinical outcomes comparable to those seen with late dialysis initiation. Compared with early-start patients, late-start patients who had chosen PD as their planned dialysis modality were less likely to commence on PD.

Just as synthetic organic chemistry once revolutionized the ability of chemists to build molecules (including those that did not exist in nature) following a basic set of design rules, cell-free synthetic biology is beginning to provide an improved toolbox and faster process for not only harnessing but also expanding the chemistry of life. At the interface between chemistry and biology, research in cell-free synthetic systems is proceeding in two different directions: using synthetic biology for synthetic chemistry and using synthetic chemistry to reprogram or mimic biology. In the coming years, the impact of advances inspired by these approaches will make possible the synthesis of nonbiological polymers having new backbone compositions, new chemical properties, new structures, and new functions., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Regulatory T cells (Tregs) help protect against autoimmune renal injury. The use of agonist antibodies and antibody/cytokine combinations to expand Tregs in vivo may have therapeutic potential for renal disease. Here, we investigated the effects of administering IL-2/IL-2Ab complexes in mice with adriamycin nephropathy, a model of proteinuric kidney disease that resembles human focal segmental glomerulosclerosis. Injecting IL-2/IL-2Ab complexes before or, to a lesser extent, after induction of disease promoted expansion of Tregs. Furthermore, administration of this complex was renoprotective, evidenced by improved renal function, maintenance of body weight, less histologic injury, and reduced inflammation. IL-2/IL-2Ab reduced serum IL-6 and renal expression of IL-6 and IL-17 but enhanced expression of IL-10 and Foxp3 in the spleen. In vitro, the addition of IL-2/IL-2Ab complexes induced rapid STAT-5 phosphorylation in CD4 T cells. In summary, these data suggest that inducing the expansion of Tregs by administering IL-2/IL-2Ab complexes is a possible strategy to treat renal disease.

Autoreactive T cells play a pivotal role in the pathogenesis of autoimmune kidney disease. T cell vaccination (TCV) may limit autoimmune disease and induce CD8+ regulatory T cells (Tregs). We used Heymann nephritis (HN), a rat model of human membranous nephritis, to study the effects of TCV on autoimmune kidney disease. We harvested CD4+ T cells from renal tubular antigen (Fx1A) -immunized rats and activated these cells in vitro to express the MHC Class Ib molecule Qa-1. Vaccination of Lewis rats with these autoreactive Fx1A-induced T cells protected against HN, whereas control-primed T cells did not. Rats that underwent TCV had lower levels of proteinuria and serum creatinine and significantly less glomerulosclerosis, tubular damage, and interstitial infiltrates. Furthermore, these rats expressed less IFN-γ and IL-6 in splenocytes, whereas the numbers of Tregs and the expression of Foxp3 were unchanged. In vitro cytotoxicity assays showed CD8+ T cell-mediated elimination of Qa-1-expressing CD4+ T cells. In vivo, TCV abrogated the increase in Qa-1-expressing CXCR5+ TFH cells observed in HN compared with controls. Taken together, these results suggest that TCV protects against autoimmune kidney disease by targeting Qa-1-expressing autoreactive CD4+ cells.

The kidney contains receptors for the cytokine IL-25, but the effects of IL-25 in CKD are unknown. Here, we induced adriamycin nephropathy in both BALB/c mice and severe combined immunodeficient (SCID) mice, and we injected IL-25 for 7 consecutive days starting at day 5 after adriamycin administration. BALB/c mice treated with IL-25 had less glomerulosclerosis, tubular atrophy, interstitial expansion, and proteinuria than control mice at day 28. IL-25 increased the levels of IL-4 and IL-13 in serum, kidney, renal draining lymph nodes, and CD4+ lymphocytes. IL-25 also directly suppressed effector macrophages in vitro and in vivo and induced alternatively activated (M2) macrophages in vivo. However, in SCID mice and in BALB/c mice treated with IL-4/13-neutralizing antibody, IL-25 failed to protect against renal injury and did not induce M2. In conclusion, IL-25 protects against renal injury in adriamycin nephropathy in mice by, at least in part, inducing Th2 immune responses., (Copyright © 2011 by the American Society of Nephrology)

Due to the anti-inflammatory properties of PUFA, it has been suggested that they may protect against kidney damage in adults. However, relatively few epidemiological studies have examined this hypothesis in human subjects. We investigated the association between dietary intakes of PUFA (n-3, n-6 and α-linolenic acid), fish and the prevalence of chronic kidney disease (CKD). A total of 2600 Blue Mountains Eye Study (1997-9) participants aged ≥ 50 years were analysed. Dietary data were collected using a semi-quantitative FFQ, and PUFA and fish intakes were calculated. Baseline biochemistry including serum creatinine was measured. Moderate CKD was defined as an estimated glomerular filtration rate of < 60 ml/min per 1·73 m2. Participants in the highest quartile of long-chain n-3 PUFA intake had a significantly reduced likelihood of having CKD compared with those in the lowest quartile of intake (multivariable-adjusted OR 0·69, 95 % CI 0·49, 0·99). α-Linolenic acid intake was positively associated with CKD (OR, per standard deviation increase in α-linolenic acid, 1·18, 95 % CI 1·05, 1·32). Total n-3 PUFA or total n-6 PUFA were not significantly associated with CKD. The highest compared with the lowest quartile of fish consumption was associated with a reduced likelihood of CKD (OR 0·68, 95 % CI 0·48, 0·97; P for trend = 0·02). The present study shows that an increased dietary intake of long-chain n-3 PUFA and fish reduces the prevalence of CKD. Hence, a diet rich in n-3 PUFA and fish could have a role in maintaining healthy kidney function, in addition to roles of these nutrients in the prevention and modulation of other diseases.

It has been shown that dietary glycemic index (GI) and fiber could have a role in the development of chronic diseases; however, the link between carbohydrate nutrition and development of chronic kidney disease (CKD) is unclear. We aimed to determine whether cross-sectional and longitudinal associations exist between carbohydrate nutrition (mean dietary GI, dietary intakes of carbohydrate, sugar, starch, and fiber) and CKD. Data included 2600 Blue Mountains Eye Study (1997-1999) participants aged ≥50 y. Baseline biochemistry including serum creatinine was measured. Moderate CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL·min(-1)·1.73 m(-2). Dietary data were collected in a semiquantitative FFQ. Cross-sectionally, participants in the 4th quartile of mean dietary GI intake compared with those in the first quartile (reference) had a 55% increased likelihood of having eGFR < 60 mL·min(-1)·1.73 m(-2) [multivariable-adjusted OR = 1.55 (95% CI = 1.07-2.26); P-trend = 0.01]. After multivariable adjustment, participants in the 4th quartile of dietary cereal fiber intake compared with those in the first quartile (reference) had a 50% reduced risk of incident moderate CKD (P-trend = 0.03). Higher baseline consumption of energy-dense, nutrient-poor sources of carbohydrate (e.g. cookies) yielded a 3-fold higher risk of incident CKD (P-trend = 0.01). In summary, we observed a novel link between high cereal fiber intake and reduced incidence of moderate CKD and this was supported by the cross-sectional association with dietary GI. Conversely, our data suggest that higher intake of energy-dense, nutrient-poor sources of carbohydrate, potentially through acute hyperglycemia, could impair renal function.

E-Cadherin/β-catenin complex plays an important role in maintaining epithelial integrity and disrupting this complex affect not only the adhesive repertoire of a cell, but also the Wnt-signaling pathway. Aberrant expression of the complex is associated with a wide variety of human malignancies and disorders of fibrosis resulting from epithelial-mesenchymal transition. These associations provide insights into the complexity that is likely responsible for the fibrosis/tumor suppressive action of E-cadherin/β-catenin.

Macrophages have heterogeneous phenotypes as they exercise their twofold role in the development and recovery of renal diseases. Some subpopulations of macrophages (M1) have a pathogenic function in renal inflammation, making them a logical target for elimination. Alternatively, M2 macrophage subpopulations resolve inflammation and repair injury, making them a potential therapeutic tool against renal injury. Here, we summarize recent findings regarding macrophage plasticity, and the various strategies for targeting or utilizing macrophages to treat renal disease. We highlight, in particular, the potential of renoprotective M2 macrophages to resolve inflammation and repair the kidney.