The Associations of Foot Process Effacement with Kidney Histopathologic Lesions and Disease Progression.

Background: Foot process effacement (FPE), a marker of podocyte injury observable via electron microscopy (EM), plays a key role in the pathophysiology of albuminuria and kidney disease progression. Whether FPE, as reported on kidney biopsies, is associated with histopathologic lesions and adverse clinical outcomes across a range of kidney diseases has not yet been explored.

Methods: We developed semi-quantitative scores from free text pathologists' descriptions of FPE severity, using EM reports from 813 participants in the Boston Kidney Biopsy Cohort (BKBC), a prospective cohort study of individuals with biopsy-confirmed kidney disease.

Circulating Proteins for Prediction of Kidney Disease Progression and Cardiovascular Outcomes: Individual Participant Data Meta-Analysis of Four Cohorts.

Introduction: KIM-1, TNFRSF1A, and TNFRSF1B have been accepted as early risk markers in diabetic kidney disease by the US Food and Drug Administration. Whether they may be useful in identifying high-risk patients for cardiovascular/kidney clinical trial enrollment in other important subgroups is uncertain.

Methods: We evaluated the potential prognostic enrichment of KIM-1, TNFRSF1A, and TNFRSF1B in four cohorts: the Atherosclerosis Risk in Communities (ARIC) (N = 4,594, mean age 76 years, 55% women, mean eGFR 68 mL/min/1.

Serum Metabolomic Markers of Dietary Potassium and Risk of CKD.

Key Points: We identified metabolomic markers of dietary potassium and diet-related metabolites that were associated with incident CKD in US adults. These metabolites may be prioritized for elucidating mechanisms that could be modified by dietary strategies to prevent CKD.

Background: Discovering metabolomic markers of dietary potassium may help improve dietary assessment of potassium and trace the effect of dietary potassium on CKD development.

Glycerol-3-phosphate contributes to the increase in FGF23 production in chronic kidney disease.

Why fibroblast growth factor 23 (FGF23) levels increase markedly in chronic kidney disease (CKD) is unknown. Recently, we found that phosphate stimulates renal production of glycerol-3-phosphate (G-3-P), which circulates to the bone to trigger FGF23 production. To assess the impact of G-3-P on FGF23 production in CKD, we compared the effect of adenine-induced CKD in mice deficient in glycerol-3-phosphate dehydrogenase 1 (Gpd1), an enzyme that synthesizes G-3-P, along with wild-type littermates.

Circulating Protein and Metabolite Correlates of Histologically Confirmed Diabetic Kidney Disease.

Rationale & Objective: Diabetic kidney disease (DKD) is one of the leading causes of end-stage kidney disease globally. We aim to identify proteomic and metabolomic correlates of histologically confirmed DKD that may improve our understanding of its pathophysiology.

Study Design: A cross-sectional study.

A Metabolomics Approach to Identify Metabolites Associated With Mortality in Patients Receiving Maintenance Hemodialysis.

Introduction: Uremic toxins contributing to increased risk of death remain largely unknown. We used untargeted metabolomics to identify plasma metabolites associated with mortality in patients receiving maintenance hemodialysis.

Methods: We measured metabolites in serum samples from 522 Longitudinal US/Canada Incident Dialysis (LUCID) study participants.

Plasma proteomics of acute tubular injury.

The kidney tubules constitute two-thirds of the cells of the kidney and account for the majority of the organ's metabolic energy expenditure. Acute tubular injury (ATI) is observed across various types of kidney diseases and may significantly contribute to progression to kidney failure. Non-invasive biomarkers of ATI may allow for early detection and drug development.

Consistency of metabolite associations with measured glomerular filtration rate in children and adults.

Background: There is interest in identifying novel filtration markers that lead to more accurate GFR estimates than current markers (creatinine and cystatin C) and are more consistent across demographic groups. We hypothesize that large-scale metabolomics can identify serum metabolites that are strongly influenced by glomerular filtration rate (GFR) and are more consistent across demographic variables than creatinine, which would be promising filtration markers for future investigation.

Methods: We evaluated the consistency of associations between measured GFR (mGFR) and 887 common, known metabolites quantified by an untargeted chromatography- and spectroscopy-based metabolomics platform (Metabolon) performed on frozen blood samples from 580 participants in Chronic Kidney Disease in Children (CKiD), 674 participants in Modification of Diet in Renal Disease (MDRD) Study and 962 participants in African American Study of Kidney Disease and Hypertension (AASK).

Serum and Urine Metabolites and Kidney Function.

Key Points: We provide an atlas of cross-sectional and longitudinal serum and urine metabolite associations with eGFR and urine albumin-creatinine ratio in an older community-based cohort. Metabolic profiling in serum and urine provides distinct and complementary insights into disease.

Background: Metabolites represent a read-out of cellular processes underlying states of health and disease.

siRNA takes a jab at hypertension.

Hypertension is a modifiable risk factor for cardiovascular disease, the leading cause of death worldwide, yet most US adults with hypertension do not meet goal blood pressure. KARDIA-1 demonstrates the efficacy of zilebesiran, a subcutaneously administered small interfering RNA, for lowering blood pressure, presenting a novel treatment option for this deadly disease..

Longitudinal Plasma Metabolome Patterns and Relation to Kidney Function and Proteinuria in Pediatric CKD.

Key Points: Longitudinal untargeted metabolomics. Children with CKD have a circulating metabolome that changes over time.

Background: Understanding plasma metabolome patterns in relation to changing kidney function in pediatric CKD is important for continued research for identifying novel biomarkers, characterizing biochemical pathophysiology, and developing targeted interventions.

Plasma Proteins Associated with Chronic Histopathologic Lesions on Kidney Biopsy.

Key Points: Proteomic profiling identified 35 blood proteins associated with chronic histopathologic lesions in the kidney. Testican-2 was expressed in the glomerulus, released by the kidney into circulation, and inversely associated with glomerulosclerosis severity. NELL1 was expressed in tubular epithelial cells, released by the kidney into circulation, and inversely associated with interstitial fibrosis and tubular atrophy severity.

Association of Integrated Proteomic and Metabolomic Modules with Risk of Kidney Disease Progression.

Key Points: Integrated analysis of proteome and metabolome identifies modules associated with CKD progression and kidney failure. Ephrin transmembrane proteins and podocyte-expressed CRIM1 and NPNT emerged as central components and warrant experimental and clinical investigation.

Background: Proteins and metabolites play crucial roles in various biological functions and are frequently interconnected through enzymatic or transport processes.

Plasma metabolites and physical function in patients undergoing hemodialysis.

Impaired physical function contributes to falls, fractures, and mortality among patients undergoing dialysis. Using a metabolomic approach, we identified metabolite alterations and effect size-based composite scores for constructs of impaired gait speed and grip strength. 108 participants incident to dialysis had targeted plasma metabolomics via liquid chromatography-mass spectrometry and physical function assessed (i.

Phosphate sensing in health and disease.

Purpose Of Review: Disruptions of phosphate homeostasis are associated with a multitude of diseases with insufficient treatments. Our knowledge regarding the mechanisms underlying metazoan phosphate homeostasis and sensing is limited. Here, we highlight four major advancements in this field during the last 12-18 months.

Gα11 deficiency increases fibroblast growth factor 23 levels in a mouse model of familial hypocalciuric hypercalcemia.

Fibroblast growth factor 23 (FGF23) production has recently been shown to increase downstream of Gαq/11-PKC signaling in osteocytes. Inactivating mutations in the gene encoding Gα11 (GNA11) cause familial hypocalciuric hypercalcemia (FHH) due to impaired calcium-sensing receptor signaling. We explored the effect of Gα11 deficiency on FGF23 production in mice with heterozygous (Gna11+/-) or homozygous (Gna11-/-) ablation of Gna11.

Glycated Albumin and Adverse Clinical Outcomes in Patients With CKD: A Prospective Cohort Study.

Rationale & Objective: Hemoglobin A (HbA) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown.

Serum Metabolomic Markers of Protein-Rich Foods and Incident CKD: Results From the Atherosclerosis Risk in Communities Study.

Rationale & Objective: While urine excretion of nitrogen estimates the total protein intake, biomarkers of specific dietary protein sources have been sparsely studied. Using untargeted metabolomics, this study aimed to identify serum metabolomic markers of 6 protein-rich foods and to examine whether dietary protein-related metabolites are associated with incident chronic kidney disease (CKD).

Study Design: Prospective cohort study.

Metabolites Associated With Uremic Symptoms in Patients With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study.

Rationale & Objective: The toxins that contribute to uremic symptoms in patients with chronic kidney disease (CKD) are unknown. We sought to apply complementary statistical modeling approaches to data from untargeted plasma metabolomic profiling to identify solutes associated with uremic symptoms in patients with CKD.

Study Design: Cross-sectional.

Maintenance of remission of ANCA vasculitis by rituximab based on B cell repopulation versus serological flare: a randomised trial.

Objective: To compare two long-term remission maintenance strategies for antineutrophil cytoplasmic antibody (ANCA) vasculitis.

Methods: We conducted a prospective, single-centre, open-label, randomised controlled trial of patients with ANCA vasculitis in remission after completing at least 2 years of fixed-schedule rituximab. In the B cell arm, rituximab was reinfused upon B cell repopulation; in the ANCA arm, rituximab was reinfused upon significant rise in ANCA level.