Publications by authors named "Bradley Dixon"

Introduction: Critically ill adults with acute kidney injury (AKI) have high morbidity and mortality and lack treatment options. We assessed the association between complement activation (urine Ba fragment levels), and AKI and organ failures.

Methods: A biorepository of critically ill adults was leveraged.

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  • The term atypical hemolytic uremic syndrome (aHUS) originated in the 1970s to differentiate between familial/sporadic cases and typical epidemic cases associated with Shiga toxin.
  • Over time, aHUS has become a broad term for various diseases that don't relate to Shiga toxin, complicating the definition and treatment strategies due to its diverse causes.
  • A group of experts used a consensus-building method called the Delphi approach to discuss and clarify the terminology and issues surrounding aHUS in light of advancements in medical science and targeted therapies.
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  • In patients with X-linked hypophosphatemia (XLH), traditional treatments can lead to nephrocalcinosis, but the connections between XLH, its treatment, and kidney function are still unclear.
  • A study analyzed kidney health in 196 children and 318 adults with XLH, with findings showing a significant prevalence of nephrocalcinosis, especially in children, and its association with reduced kidney function.
  • Results indicated that nephrocalcinosis was common in both age groups, with children showing more symptoms related to kidney function compared to adults, highlighting the need for deeper understanding and monitoring of kidney health in XLH patients.*
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Rationale & Objective: Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA) caused by complement dysregulation. Ravulizumab is a C5i approved for the treatment of aHUS. This analysis assessed long-term outcomes of ravulizumab in adults and pediatric patients with aHUS.

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Background: Recurrence of focal segmental glomerulosclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) after kidney transplant leads to significant morbidity and potentially earlier allograft loss. To date however, reported rates, risk factors and treatment outcomes have varied widely.

Methods: We applied computational phenotypes to a multicenter aggregation of electronic health records data from 7 large pediatric health systems in the USA, to identify recurrence rates, risk factors, and treatment outcomes.

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We investigated the risks of post-acute and chronic adverse kidney outcomes of SARS-CoV-2 infection in the pediatric population via a retrospective cohort study using data from the RECOVER program. We included 1,864,637 children and adolescents under 21 from 19 children's hospitals and health institutions in the US with at least six months of follow-up time between March 2020 and May 2023. We divided the patients into three strata: patients with pre-existing chronic kidney disease (CKD), patients with acute kidney injury (AKI) during the acute phase (within 28 days) of SARS-CoV-2 infection, and patients without pre-existing CKD or AKI.

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  • Dysregulated complement activation is a major factor in diseases like C3 glomerulopathy (C3G) and other related kidney conditions, with pegcetacoplan being explored as a potential treatment to reduce kidney damage.
  • A phase 2 study on pegcetacoplan showed significant reductions in proteinuria (up to 65.4%) in C3G patients over 48 weeks, alongside stable kidney function and improvements in certain biomarkers.
  • The treatment demonstrated a favorable safety profile, with common side effects being mild, such as respiratory infections and nausea, and no serious adverse events were reported.
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Objective: Word list-learning tasks are commonly used to evaluate auditory-verbal learning and memory. However, different frequencies of word usage, subtle meaning nuances, unique word phonology, and different preexisting associations among words make translation across languages difficult. We administered lists of consonant-vowel-consonant (CVC) nonword trigrams to independent American and Italian young adult samples.

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Background: Identification of abnormal blood pressure (BP) in children requires normative data. We sought to examine the feasibility of using "real-world" office BP data obtained from electronic health records (EHR) to generate age-, sex- and height-specific BP percentiles for children.

Methods: Using data collected 01/01/2009-8/31/2021 from eight large children's healthcare organisations in PEDSnet, we applied a mixed-effects polynomial regression model with random slopes to generate Z-scores and BP percentiles and compared them with currently used normative BP distributions published in the 2017 American Academy of Paediatrics (AAP) Clinical Practise Guidelines (CPG).

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Rationale & Objective: PRESERVE seeks to provide new knowledge to inform shared decision-making regarding blood pressure (BP) management for pediatric chronic kidney disease (CKD). PRESERVE will compare the effectiveness of alternative strategies for monitoring and treating hypertension on preserving kidney function; expand the National Patient-Centered Clinical Research Network (PCORnet) common data model by adding pediatric- and kidney-specific variables and linking electronic health record data to other kidney disease databases; and assess the lived experiences of patients related to BP management.

Study Design: Multicenter retrospective cohort study (clinical outcomes) and cross-sectional study (patient-reported outcomes [PROs]).

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Ravulizumab and eculizumab are complement C5 inhibitors approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Ravulizumab requires less frequent infusions than eculizumab, which may reduce treatment burden. This study investigated patients' treatment preferences and the impact of both treatments on patient and caregiver quality of life.

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Background: IgA vasculitis is the most common vasculitis in children and is often complicated by acute nephritis (IgAVN). Risk of chronic kidney disease (CKD) among children with IgAVN remains unknown. This study aimed to describe the clinical management and kidney outcomes in a large cohort of children with IgAVN.

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Key Points: Complement activation, specifically factor B, is implicated in AKI pathogenesis in animal models. Urine Ba (an activation fragment of factor B) was significantly higher in critically ill children with stage 3 AKI and sepsis-AKI. If larger studies show similar association between urine Ba and AKI severity, clinical trials of factor B inhibition are warranted.

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Background: The objectives of this study were to use electronic health record data from a US national multicenter pediatric network to identify a large cohort of children with CKD, evaluate CKD progression, and examine clinical risk factors for kidney function decline.

Methods: This retrospective cohort study identified children seen between January 1, 2009, to February 28, 2022. Data were from six pediatric health systems in PEDSnet.

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  • * Two phase 2 clinical studies were conducted on the orally active factor D inhibitor danicopan, aiming to assess its impact on C3G and related conditions.
  • * Although danicopan was found to be safe, it failed to provide consistent treatment benefits or sufficiently inhibit the alternative pathway, indicating that stronger and sustained action is needed for effective patient outcomes.
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  • C3 glomerulopathy (C3G) is a rare kidney disease caused by issues in the complement system, specifically the alternative pathway, and the study aimed to analyze biomarkers in patients participating in phase 2 trials of danicopan, a factor D inhibitor.
  • Twenty-nine patients were evaluated, revealing systemic activation of the complement pathway with significant correlations between various complement biomarkers and kidney health metrics, such as eGFR and proteinuria.
  • The findings highlight strong relationships between complement biomarkers and kidney function/histology, potentially enhancing the understanding and classification of C3G patients.
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Background: Acute kidney injury (AKI) is common in lupus nephritis (LN) and a risk factor for development of chronic kidney disease. In adults with LN, AKI severity correlates with the incidence of kidney failure and patient survival. Data on AKI outcomes in children with LN, particularly those requiring kidney replacement therapy (KRT), are limited.

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The complement cascade is an important part of the innate immune system. In addition to helping the body to eliminate pathogens, however, complement activation also contributes to the pathogenesis of a wide range of kidney diseases. Recent work has revealed that uncontrolled complement activation is the key driver of several rare kidney diseases in children, including atypical hemolytic uremic syndrome and C3 glomerulopathy.

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Background: Children with glomerular disease have unique risk factors for compromised bone health. Studies addressing skeletal complications in this population are lacking.

Methods: This retrospective cohort study utilized data from PEDSnet, a national network of pediatric health systems with standardized electronic health record data for more than 6.

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Unlabelled: Acute antibody-mediated rejection (AMR) is mediated by the activation of the classical complement system in addition to noncomplement-dependent inflammatory pathways. Complement fixation by donor-specific antibodies leads to cleavage of the complement proteins C4, C3, and C5 to produce multiple complement split-products (CSP) and the end-effector membrane attack complex, C5b-9. In this study, we investigate CSP as potential biomarkers for AMR.

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IgA vasculitis (IgAV, also known as Henoch-Schönlein purpura or HSP) is a vasculitis of small vessels involving multiple organs, particularly of the joints, gastrointestinal tract, skin, and kidneys. Growing laboratory evidence has shown that complement plays a key role in the pathogenesis of IgAV, although direct evidence of this association in patients is lacking. We report a child with IgAV associated with clinical features of hypertension, nephrotic range proteinuria, acute kidney injury, and low serum C3, with histopathologic findings on renal biopsy of membranoproliferative glomerulonephritis with C3 and IgA co-dominance, and extensive complement derangements.

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Background: Children who are critically ill with AKI suffer from high morbidity and mortality rates, and lack treatment options. Emerging evidence implicates the role of complement activation in AKI pathogenesis, which could potentially be treated with complement inhibitors. The purpose of this study is to evaluate the association between complement activation fragments and severity of AKI in children who are critically ill.

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What Is Known And Objective: The C5 inhibitor eculizumab is the standard of care for treatment of atypical haemolytic uraemic syndrome (aHUS). Ravulizumab, a next-generation C5 inhibitor, was engineered to have a longer terminal half-life than eculizumab. We describe practical benefits of the advanced ravulizumab 100 mg/mL formulation.

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