Search

We use impedance spectroscopy to investigate the dielectric response in polycrystalline, lead-free 0.5(Ba 0.7 Ca 0.3 )TiO 3 –0.5Ba(Zr 0.2 Ti 0.8 )O 3 (BCZT) ferroelectric thin films as a function of amplitude E 0 and frequency f of an applied ac electric field. Impedance spectra from f = 10 Hz to 1 MHz were collected at different E 0 on polycrystalline BCZT capacitor stacks, grown by pulsed laser deposition on platinized Si substrates and covered with Au electrodes. Deconvolution of the spectra is achieved by fitting the measured impedance to the impedance of an equivalent-circuit model of the capacitor stacks, including a recently proposed domain-wall pinning element Z DW . From an extended data analysis, we quantify the coupling strength between dielectric nonlinearity and frequency dispersion in the BCZT thin films, and we obtain a schematic diagram of the different domain-wall-motion regimes. Our results indicate that the presence of grain boundaries in BCZT reduces the coupling strength and suppresses the motion of internal domain-wall segments and also the irreversible center-of-mass motion of the domain walls. [ABSTRACT FROM AUTHOR]

Early islet cell loss is a significant problem in clinical islet cell transplantation. Diverse stress stimuli induce innate immune responses in islets that contribute to beta-cell dysfunction, inflammation, and loss. Here, we show that cytokine-stimulated murine islets express multiple inflammatory chemokines that recruit T-cells and thereby impair islet function in vitro and in vivo. Both nonislet ductal and exocrine elements and the individual islet cellular components contribute to this innate immune response. CD4+ CD25+ regulatory T-cells inhibit islet chemokine expression through a cell contact-dependent, soluble factor-independent mechanism and inhibit effector T-cell migration to the islet. Regulatory T-cells can also migrate to stimulated islets. Cotransfer of regulatory T-cells with islets in a transplantation model prevents islet innate immune responses and inflammation and preserves normal architecture and engraftment. Regulatory T-cell inhibition of multiple components of innate immune responses may be a fundamental aspect of their function that influences ischemia-reperfusion injury and adaptive immunity. [ABSTRACT FROM AUTHOR]

Glucose containing solutions, the basis of peritoneal dialysis fluids, affect the proliferation and regeneration of peritoneal mesothelial cells (MsC). The aim of this study was to examine mechanisms of glucose transport into MsC, that is, the expression of facilitative glucose transporters (GLUT) and the Na(+)-dependent glucose transporter (SGLT1) in human primary MsC and a transfected MsC line. Since expression of both transporters is differentiation dependent, we investigated the effects of cell differentiation induced by culturing MsC on membranes or by addition of hexamethylene bisacetamide (HMBA; 6 mM), which enhances SGLT1 expression in LLC-PK1 cells. Levels of mRNA for GLUT1 through GLUT4 and SGLT1 were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR). The presence of the corresponding proteins was examined by Western blotting and localized by immunofluorescence. Active, Na(+)-dependent glucose transport was assessed by alpha-methyl-D-[14C]glucopyranoside (AMG) with and without the SGLT1-specific inhibitor phlorizin and by patch clamp experiments in NaCl or choline-chloride, For Na(+) dependent glucose uptake choline chloride instead of NaCl served as negative control. Facilitative transport was assessed using 2-fluoro-2-deoxy-[14C]-D-glucose (FDG) with and without the inhibitors cytochalasin B or phloretin. Primary and transfected MsC express GLUT1 and GLUT3 mRNA while no transcripts were found for GLUT2 and GLUT4. No SGLT1 transcript was detectable in subconfluent cells. Semiquantitative RT-PCR analysis documented that the addition of the differentiation inducer HMBA to confluent cultures or growth of MsC on membranes for seven days produced a down-regulation of mRNA for GLUT1, no change for GLUT3, and a substantial increase for SGLT1 mRNA. Under these conditions MsC express SGLT1 protein and possess a Na(+)-dependent glucose uptake as assessed by AMG. Phlorizin (1 mM) inhibits AMG uptake by 30 to 40%. In patch clamp experiments the addition of extracellular glucose depolarized the membrane potential only in the presence of sodium. These results indicate that differentiated MsC express GLUT1, GLUT3, and SGLT1. Further characterization of these transport mechanisms and their regulation may help to understand the cellular effects of glucose on MsC in peritoneal dialysis. [ABSTRACT FROM AUTHOR]

Pertussis (whooping cough) is a vaccine-preventable but re-emerging, highly infectious respiratory disease caused by Bordetella pertussis. There are currently no effective treatments for pertussis, complicating care for non-vaccinated individuals, especially newborns. Disease manifestations are predominantly caused by pertussis toxin (PT), a pivotal virulence factor classified as an ADP-ribosylating AB-type protein toxin. In this work, an unbiased approach using peptide libraries, bioassay-guided fractionation and mass spectrometry revealed α 1 -antitrypsin (α 1 AT) as a potent PT inhibitor. Biochemistry-, cell culture- and molecular modeling-based in vitro experimentation demonstrated that the α 1 AT mode of action is based on blocking PT-binding to the host target cell surface. In the infant mouse model of severe pertussis, α 1 AT expression was reduced upon infection. Further, systemic administration of α 1 AT significantly reduced B. pertussis-induced leukocytosis, which is a hallmark of infant infection and major risk factor for fatal pertussis. Taken together our data demonstrates that α 1 AT is a novel PT inhibitor and that further evaluation and development of α 1 AT as a therapeutic agent for pertussis is warranted. Importantly, purified α 1 AT is already in use clinically as an intravenous augmentation therapy for those with genetic α 1 AT deficiency and could be repurposed to clinical management of pertussis., Competing Interests: Conflicts of Interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

While the native arterio-venous fistula (AVF) remains the first choice in vascular access for most hemodialysis patients, tunneled hemodialysis catheters (tHDC) continue to be an option in selected patients. Since timely access to vascular surgery-due to delayed referral or resource limitations-is not always possible, nephrologists have to become more actively involved in planning, creation and monitoring of vascular access. Moreover, this approach could also strengthen patient-centered care in nephrology. This manuscript reviews the current standard in tHDC creation, patient selection and strategies to mitigate the risk of infectious complications and catheter thrombosis. Presentation of novel developments in catheter placement with ultrasound-guided or ECG-guided positioning, their benefits and possible disadvantages emphasizes the complexity of vascular access planning. We offer an approach for choice of insertion method, depending on selected side and existing resources and set focus on the necessity and required resources of 'interventional nephrology' training programs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

Background: The complement factor 5 (C5)-inhibitor eculizumab has been established as standard-of-care for the treatment of atypical hemolytic uremic syndrome (aHUS). In 2021, the long-acting C5-inhibitor ravulizumab was approved, extending intervals of intravenous treatment from two to eight weeks resulting in improvement of quality of life for patients and lowering direct and indirect therapy associated costs., Methods: This multicenter, retrospective data analysis of 32 adult patients with aHUS (including 10 kidney transplant recipients) treated with eculizumab for at least three months and switched to ravulizumab aims to evaluate the safety and efficacy of switching medication in the real-world setting. Hematologic parameters, kidney function, concurrent therapy and aHUS associated events were evaluated three months before and until up to 12 months after switching to ravulizumab., Results: Mean age (range) at ravulizumab initiation was 41 years (19-78 years) and 59% of the patients were female. Genetic analysis was available for all patients with 72% showing a pathogenic variant. Median time (range) on eculizumab before switching was 20 months (3-120 months). No new events of TMA or worsening of renal function were reported during up to 12 months of follow-up during ravulizumab treatment., Conclusions: This is the largest, non-industry derived, multi-center retrospective analysis of adult patients with aHUS switching C5-inhibitor treatment from eculizumab to ravulizumab in the real-world setting. Switching to ravulizumab was safe and efficient resulting in sustained hematological stability and preservation of renal function., (© 2024. The Author(s).)

Background: ANCA (antineutrophil cytoplasmatic antibody)-associated vasculitis (AAV) mainly affects elderley people but adjusted therapy concepts for this patient group are lacking., Aim: The aim of this study was therefore to analyze differences in course and outcome of patients with AAV with respect to age., Materials and Methods: 62 patients were analyzed for treatment response, of whom 53 (85%) experienced adverse events (AE and SAE) that could be evaluated. Older (> 65 yrs.) versus younger (< 65 yrs.) patients were compared. Treatment response was assessed at 6 months, complications were assessed over 18 months., Results: Treatment response was not seen to differ by age groups. In multiple logistic regression, pulmonary involvement (OR = 6,9; CI = 1,7-27,8, p < 0,01) and ΔGFR [ml/min] (OR = 0,93; CI = 0,89-0,97, p < 0,01) were predictors of SAE. 14 patients had more than 1 SAE. Again, pulmonary involvement (28,2% vs. 78,6%, p < 0,01) was a risk factor and older patients (78,6% vs. 43,6%, p = 0,025) were more frequently affected. Patients with multiple SAEs received glucocorticoids of more than 5 mg/d for longer periods of time (171 ± 65 days vs. 120 ± 70 days, p = 0,03)., Discussion: No differences were found between older and younger patients with regard to treatment response. Multiple SAEs occurred more frequently in elderly patients. There was a correlation between pulmonary manifestation and duration of glucocorticoid therapy with a complicated course. The most frequent SAEs were infections requiring hospitalisation., Conclusion: Therapy for elderly patients should be individualized with the goal of a fast reduction of glucocorticoids. Special monitoring is indicated for elderly patients, especially those with pulmonary involvement., (© 2022. The Author(s).)

Introduction: Radiographic fluoroscopy is the current standard for placement of tunneled central venous catheters (CVCs) for hemodialysis. Radiographic fluoroscopy requires structural and personnel infrastructure and exposes the patient to ionizing radiation. Here, we investigate the feasibility of solely ultrasound-guided placement of tunneled central venous dialysis catheters (USCVCs)., Methods: We evaluated prospectively collected single-center data regarding safety and catheter function of 134 consecutive patients who underwent USCVC implantation between 2020 and 2021. We used the inset guidewire to visualize the position of the catheter tip. In the case of inadequate visibility by ultrasound, we used intracardiac electrocardiography (ECG) recording or agitated saline. A total of 1844 catheter days were assessed. The optimal CVC position was defined as being within the upper right atrium (URA) and middle to deep right atrium., Results: Of the 134 USCVCs, 87% were placed on the right side. The primary success rate for optimal tip position and catheter function was 98%. Of the USCVCs, 97% were placed solely by ultrasound. Regarding positioning, 6% were in the vena cava superior zone, 70% in the URA and 24% in the middle to deep right atrium, resulting in a rate of 94% with optimal positioning. Effective blood flow averaged 292 ± 39 ml/min. There were no immediate procedure-associated complications., Conclusion: Placement of CVC for hemodialysis solely by ultrasound is an effective alternative to fluoroscopy-assisted placement., (© 2023 International Society of Nephrology. Published by Elsevier Inc.)

Rationale & Objective: Donor acute kidney injury (AKI) activates innate immunity, enhances HLA expression in the kidney allograft, and provokes recipient alloimmune responses. We hypothesized that injury and inflammation that manifested in deceased-donor urine biomarkers would be associated with higher rates of biopsy-proven acute rejection (BPAR) and allograft failure after transplantation., Study Design: Prospective cohort., Setting & Participants: 862 deceased donors for 1,137 kidney recipients at 13 centers., Exposures: We measured concentrations of interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) in deceased donor urine. We also used the Acute Kidney Injury Network (AKIN) criteria to assess donor clinical AKI., Outcomes: The primary outcome was a composite of BPAR and graft failure (not from death). A secondary outcome was the composite of BPAR, graft failure, and/or de novo donor-specific antibody (DSA). Outcomes were ascertained in the first posttransplant year., Analytical Approach: Multivariable Fine-Gray models with death as a competing risk., Results: Mean recipient age was 54 ± 13 (SD) years, and 82% received antithymocyte globulin. We found no significant associations between donor urinary IL-18, KIM-1, and NGAL and the primary outcome (subdistribution hazard ratio [HR] for highest vs lowest tertile of 0.76 [95% CI, 0.45-1.28], 1.20 [95% CI, 0.69-2.07], and 1.14 [95% CI, 0.71-1.84], respectively). In secondary analyses, we detected no significant associations between clinically defined AKI and the primary outcome or between donor biomarkers and the composite outcome of BPAR, graft failure, and/or de novo DSA., Limitations: BPAR was ascertained through for-cause biopsies, not surveillance biopsies., Conclusions: In a large cohort of kidney recipients who almost all received induction with thymoglobulin, donor injury biomarkers were associated with neither graft failure and rejection nor a secondary outcome that included de novo DSA. These findings provide some reassurance that centers can successfully manage immunological complications using deceased-donor kidneys with AKI., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Perovskite solar cells promise to deliver high efficiencies at low manufacturing costs. Yet on their way towards commercialization, they have to face the associated risk of potential lead leakage into the environment after damage to the cell's encapsulation. Here we present a new approach to generate a lead binding coating, based on a layer-by-layer deposition of biopolymers. A lead-adsorbing functionality was shown after subsequent crosslinking, demonstrating a high binding capacity. The lead binding capabilities could be further enhanced by increasing the thickness of the coatings, analyzed both in the supernatant and on the surface of the coated material. The thin-layered coating had a thickness of less than one micrometer, was stable even under low pH conditions and could successfully be transferred onto different substrates, ranging from silicon, gold and glass substrates to polymeric nonwoven materials with high surface areas, further increasing its lead binding capacity. This newly described coating was applied within perovskite solar cell stacks without impeding the overall efficiency but strongly reducing the amount of lead released after simulated rain tests on devices with damaged encapsulation. Accordingly, incorporation of lead-binding polyelectrolyte multilayers inside the encapsulation of perovskite solar cells shows great potential to limit the perovskite solar cells inherent risk of lead leakage in a sustainable manner., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Autosomal Dominant Tubulointerstitial Kidney Disease (ADTKD) is caused by mutations in one of at least five genes and leads to kidney failure usually in mid adulthood. Throughout the literature, variable numbers of families have been reported, where no mutation can be found and therefore termed ADTKD-not otherwise specified. Here, we aim to clarify the genetic cause of their diseases in our ADTKD registry. Sequencing for all known ADTKD genes was performed, followed by SNaPshot minisequencing for the dupC (an additional cytosine within a stretch of seven cytosines) mutation of MUC1. A virtual panel containing 560 genes reported in the context of kidney disease (nephrome) and exome sequencing were then analyzed sequentially. Variants were validated and tested for segregation. In 29 of the 45 registry families, mutations in known ADTKD genes were found, mostly in MUC1. Sixteen families could then be termed ADTKD-not otherwise specified, of which nine showed diagnostic variants in the nephrome (four in COL4A5, two in INF2 and one each in COL4A4, PAX2, SALL1 and PKD2). In the other seven families, exome sequencing analysis yielded potential disease associated variants in novel candidate genes for ADTKD; evaluated by database analyses and genome-wide association studies. For the great majority of our ADTKD registry we were able to reach a molecular genetic diagnosis. However, a small number of families are indeed affected by diseases classically described as a glomerular entity. Thus, incomplete clinical phenotyping and atypical clinical presentation may have led to the classification of ADTKD. The identified novel candidate genes by exome sequencing will require further functional validation., (Copyright © 2022 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The term frailty describes a complex syndrome of reduced resistance to stress factors as a consequence of age-related degeneration in various organ systems.In the general population frailty is associated with poor clinical outcomes, including an increased risk of falls, hospitalization, functional impairment and mortality. Frailty occurs earlier and its prevalence is higher in patients with chronic kidney disease (CKD) compared to the general population. Frail patients with CKD, on dialysis or not, have reduced quality of life and increased hospitalization and mortality rates, regardless of age, sex or comorbidities.The identification of frailty in patients with CKD can lead to the detection of important and potentially modifiable risk factors. Early nephrological evaluation coupled with an interdisciplinary approach including primary care physicians, geriatricians, physiotherapists, occupational therapists and nutritionists, is fundamental in the prevention of frailty as well as in the management of frail patients with CKD.Several instruments have been developed to screen for and assess the degree of frailty; however, there is currently no recommendation as to which should be used in nephrology and how to manage frail patients with CKD. In this article we suggest an approach based on a multidimensional, interdisciplinary evaluation aimed at the early identification and management of frail CKD patients independent of the clinical setting of admission; however, more important than the method used is the need to identify and follow-up on frail CKD patients., (© 2021. The Author(s).)

Background: De novo post-transplant diabetes mellitus (PTDM) is a common complication after kidney transplant (KT). Most recent studies are single center with various approaches to outcome ascertainment., Methods: In a multicenter longitudinal cohort of 632 nondiabetic adult kidney recipients transplanted in 2010-2013, we ascertained outcomes through detailed chart review at 13 centers. We hypothesized that donor characteristics, such as sex, HCV infection, and kidney donor profile index (KDPI), and recipient characteristics, such as age, race, BMI, and increased HLA mismatches, would affect the development of PTDM among KT recipients. We defined PTDM as hemoglobin A1c ≥6.5%, pharmacological treatment for diabetes, or documentation of diabetes in electronic medical records. We assessed PTDM risk factors and evaluated for an independent time-updated association between PTDM and graft failure using regression., Results: Mean recipient age was 52±14 years, 59% were male, 49% were Black. Cumulative PTDM incidence 5 years post-KT was 29% (186). Independent baseline PTDM risk factors included older recipient age ( P <0.001) and higher BMI ( P =0.006). PTDM was not associated with all-cause graft failure (adjusted hazard ratio (aHR), 1.10; 95% CI, 0.78 to 1.55), death-censored graft failure (aHR, 0.85; 95% CI, 0.53 to 1.37), or death (aHR, 1.31; 95% CI, 0.84 to 2.05) at median follow-up of 6 (interquartile range, 4.0-6.9) years post-KT. Induction and maintenance immunosuppression were not different between patients who did and did not develop PTDM., Conclusions: PTDM occurred commonly, and higher baseline BMI was associated with PTDM. PTDM was not associated with graft failure or mortality during the 6-year follow-up, perhaps due to the short follow-up time., Competing Interests: C.R. Parikh reports receiving a consulting fee from and Genfit (Data Safety Monitoring Board) and Renalytix (Advisory Board), and reports receiving grant/research support from National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Heart, Lung and Blood Institute (NHLBI). E. Akalin reports receiving a research grant from CareDx and National Institutes of Health (NIH). F.L. Weng reports receiving NIH grant support from the National Institute on Minority Health and Health Disparities (NIMHD) (R01MD00766405). J.S. Bromberg reports receiving grant support from NIH (NIDDK/National Institute of Allergy and Infectious Diseases [NIAID]/NIMHD/NHLBI). M.D. Doshi reports receiving salary support from NIDDK. M.N. Harhay reports receiving NIH grant support from NIDDK (K23DK105207 and R01DK124388) and National Science Foundation (NSF) grant support (award 2035007). P.P. Reese reports epidemiology consulting for VALHeath related to identifying patients with CKD; reports receiving investigator-initiated and collaborative grants from AbbVie and Merck to the University of Pennsylvania to support trials of transplanting organs from donors with hepatitis C into hepatitis C–negative recipients; reports receiving investigator-initiated grants from CVS to the University of Pennsylvania to support studies of medication adherence; and reports being an Associate Editor for American Journal of Kidney Disease. S.G. Mansour reports being supported by the American Heart Association (18CDA34110151) and Patterson Trust Fund. S. Mohan reports receiving grant and research support from the NIH (NIDDK/NIAID/NIHMD/NIBIB) and NSF; reports receiving consulting fees from Angion BIomedica; and reports being Deputy Editor, Kidney International Reports. All remaining authors have nothing to disclose., (Copyright © 2021 by the American Society of Nephrology.)

Introduction: This 12-month, noninterventional study on routine clinical practice in Germany evaluated renal function in stable kidney transplant recipients converted from immediate-release tacrolimus (IR-T) to prolonged-release tacrolimus (PR-T)., Methods: Renal function was assessed in 183 patients by estimated glomerular filtration rate using the modification of diet in renal disease-4 formula. Self-reported gastrointestinal health-related quality of life, adherence, satisfaction with PR-T, suspected rejection episodes, and safety were also assessed at conversion and at 3, 6, and 12 months., Results: Conversion from IR-T to PR-T resulted in stable kidney function over 12 months, with a difference in estimated glomerular filtration rate between the first and final visits of 0.1 mL/min/1.73 m 2 (95% confidence interval, -1.6, 1.8). Eight patients experienced an acute rejection episode (4.4%). At each assessment, gastrointestinal health-related quality of life was low and adherence was high. Most patients reported that they were very satisfied (69.8%) or satisfied (28.1%) with PR-T at the final visit. Among patients reporting a preference, 78.4% preferred PR-T, 2.2% preferred IR-T, and 19.4% reported no preference. The safety profile of PR-T was consistent with that previously described., Conclusion: Conversion of stable kidney transplant recipients from IR-T to PR-T provided stable kidney and graft function over 12 months (Verband Forschender Arzneimittelhersteller--registered study: NIS ADV-02)., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Objectives: BK polyomavirus (BKV) infection commonly complicates kidney transplantation, contributing to morbidity and allograft failure. The virus is often donor-derived and influenced by ischemia-reperfusion processes and disruption of structural allograft integrity. We hypothesized that deceased-donor AKI associates with BKV infection in recipients., Design, Setting, Participants, & Measurements: We studied 1025 kidney recipients from 801 deceased donors transplanted between 2010 and 2013, at 13 academic centers. We fitted Cox proportional-hazards models for BKV DNAemia (detectable in recipient blood by clinical PCR testing) within 1 year post-transplantation, adjusting for donor AKI and other donor- and recipient-related factors. We validated findings from this prospective cohort with analyses for graft failure attributed to BKV within the Organ Procurement and Transplantation Network (OPTN) database., Results: The multicenter cohort mean kidney donor profile index was 49±27%, and 26% of donors had AKI. Mean recipient age was 54±13 years, and 25% developed BKV DNAemia. Donor AKI was associated with lower risk for BKV DNAemia (adjusted hazard ratio, 0.53; 95% confidence interval, 0.36 to 0.79). In the OPTN database, 22,537 (25%) patients received donor AKI kidneys, and 272 (0.3%) developed graft failure from BKV. The adjusted hazard ratio for the outcome with donor AKI was 0.7 (95% confidence interval, 0.52 to 0.95)., Conclusions: In a well-characterized, multicenter cohort, contrary to our hypothesis, deceased-donor AKI independently associated with lower risk for BKV DNAemia. Within the OPTN database, donor AKI was also associated with lower risk for graft failure attributed to BKV., Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021&#95;03&#95;10&#95;CJN18101120&#95;final.mp3., (Copyright © 2021 by the American Society of Nephrology.)