Reprogramming of Energy Metabolism in Human PKD1 Polycystic Kidney Disease: A Systems Biology Analysis.

Multiple alterations of cellular metabolism have been documented in experimental studies of autosomal dominant polycystic kidney disease (ADPKD) and are thought to contribute to its pathogenesis. To elucidate the molecular pathways and transcriptional regulators associated with the metabolic changes of renal cysts in ADPKD, we compared global gene expression data from human PKD1 renal cysts, minimally cystic tissues (MCT) from the same patients, and healthy human kidney cortical tissue samples. We found gene expression profiles of PKD1 renal cysts were consistent with the Warburg effect with gene pathway changes favoring increased cellular glucose uptake and lactate production, instead of pyruvate oxidation. Additionally, mitochondrial energy metabolism was globally depressed, associated with downregulation of gene pathways related to fatty acid oxidation (FAO), branched-chain amino acid (BCAA) degradation, the Krebs cycle, and oxidative phosphorylation (OXPHOS) in renal cysts. Activation of mTORC1 and its two target proto-oncogenes, HIF-1α and MYC, was predicted to drive the expression of multiple genes involved in the observed metabolic reprogramming (e.g., GLUT3, HK1/HK2, ALDOA, ENO2, PKM, LDHA/LDHB, MCT4, PDHA1, PDK1/3, MPC1/2, CPT2, BCAT1, NAMPT); indeed, their predicted expression patterns were confirmed by our data. Conversely, we found AMPK inhibition was predicted in renal cysts. AMPK inhibition was associated with decreased expression of PGC-1α, a transcriptional coactivator for transcription factors PPARα, ERRα, and ERRγ, all of which play a critical role in regulating oxidative metabolism and mitochondrial biogenesis. These data provide a comprehensive map of metabolic pathway reprogramming in ADPKD and highlight nodes of regulation that may serve as targets for therapeutic intervention.

Sex differences in kidney metabolism may reflect sex-dependent outcomes in human diabetic kidney disease.

Diabetic kidney disease (DKD) is the main cause of chronic kidney disease (CKD) and progresses faster in males than in females. We identify sex-based differences in kidney metabolism and in the blood metabolome of male and female individuals with diabetes. Primary human proximal tubular epithelial cells (PTECs) from healthy males displayed increased mitochondrial respiration, oxidative stress, apoptosis, and greater injury when exposed to high glucose compared with PTECs from healthy females. Male human PTECs showed increased glucose and glutamine fluxes to the TCA cycle, whereas female human PTECs showed increased pyruvate content. The male human PTEC phenotype was enhanced by dihydrotestosterone and mediated by the transcription factor HNF4A and histone demethylase KDM6A. In mice where sex chromosomes either matched or did not match gonadal sex, male gonadal sex contributed to the kidney metabolism differences between males and females. A blood metabolomics analysis in a cohort of adolescents with or without diabetes showed increased TCA cycle metabolites in males. In a second cohort of adults with diabetes, females without DKD had higher serum pyruvate concentrations than did males with or without DKD. Serum pyruvate concentrations positively correlated with the estimated glomerular filtration rate, a measure of kidney function, and negatively correlated with all-cause mortality in this cohort. In a third cohort of adults with CKD, male sex and diabetes were associated with increased plasma TCA cycle metabolites, which correlated with all-cause mortality. These findings suggest that differences in male and female kidney metabolism may contribute to sex-dependent outcomes in DKD.

Ensuring Indigenous co-leadership in health research: a Can-SOLVE CKD case example.

BACKGROUND: Indigenous people are insightful and informed about their own health and wellness, yet their visions, strengths and knowledge are rarely incorporated into health research. This can lead to subpar engagement or irrelevant research practices, which exacerbates the existing health inequities Indigenous people experience compared to the non-Indigenous population. Data consistently underscores the importance of Indigenous self-determination in research as a means to address health inequities. However, there are few formal methods to support this goal within the existing research context, which is dominated by Western perspectives. MAIN TEXT: Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (Can-SOLVE CKD) is a patient-oriented research network in Canada that recognizes the need to create the space to facilitate Indigenous self-determination in research. Indigenous members of the network therefore created and evolved a unique group, called the Indigenous Peoples' Engagement and Research Council (IPERC). IPERC plays a critical role in informing Can-SOLVE CKD research priorities, as well as creating tools to support Indigenous-specific research and engagement. This approach ensures that Indigenous voices and knowledge are critical threads within the fabric of the network's operations and research projects. Here, we describe the methods taken to create a council such as IPERC, and provide examples of initiatives by the council that aim to increase Indigenous representation, participation and partnership in research. We share lessons learned on what factors contribute to the success of IPERC, which could be valuable for other organizations interested in creating Indigenous-led research councils. CONCLUSION: Indigenous self-determination in research is critical for addressing health inequities. Here, we present a unique model, led by a council of diverse Indigenous people, which could help reduce health equities and lead to a better era of research for everyone.

Urinary angiotensin-converting enzyme 2 and metabolomics in COVID-19-mediated kidney injury.

Background: Angiotensin-converting enzyme 2 (ACE2), the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is highly expressed in the kidneys. Beyond serving as a crucial endogenous regulator of the renin-angiotensin system, ACE2 also possess a unique function to facilitate amino acid absorption. Our observational study sought to explore the relationship between urine ACE2 (uACE2) and renal outcomes in coronavirus disease 2019 (COVID-19). Methods: In a cohort of 104 patients with COVID-19 without acute kidney injury (AKI), 43 patients with COVID-19-mediated AKI and 36 non-COVID-19 controls, we measured uACE2, urine tumour necrosis factor receptors I and II (uTNF-RI and uTNF-RII) and neutrophil gelatinase-associated lipocalin (uNGAL). We also assessed ACE2 staining in autopsy kidney samples and generated a propensity score-matched subgroup of patients to perform a targeted urine metabolomic study to describe the characteristic signature of COVID-19. Results: uACE2 is increased in patients with COVID-19 and further increased in those that developed AKI. After adjusting uACE2 levels for age, sex and previous comorbidities, increased uACE2 was independently associated with a >3-fold higher risk of developing AKI [odds ratio 3.05 (95% confidence interval 1.23‒7.58), P = .017]. Increased uACE2 corresponded to a tubular loss of ACE2 in kidney sections and strongly correlated with uTNF-RI and uTNF-RII. Urine quantitative metabolome analysis revealed an increased excretion of essential amino acids in patients with COVID-19, including leucine, isoleucine, tryptophan and phenylalanine. Additionally, a strong correlation was observed between urine amino acids and uACE2. Conclusions: Elevated uACE2 is related to AKI in patients with COVID-19. The loss of tubular ACE2 during SARS-CoV-2 infection demonstrates a potential link between aminoaciduria and proximal tubular injury.

Involving Patient Partners in the KRESCENT Peer Review: Intent, Process, Challenges, and Opportunities.

Purpose of review: The Kidney Research Scientist Core Education and National Training (KRESCENT) is a national Canadian training program for kidney scientists, funded by the Kidney Foundation of Canada (KFOC), the Canadian Institutes of Health Research (CIHR), and the Canadian Society of Nephrology (CSN). We describe our first year of incorporating patient partners into a scientific peer-review committee, the 2017 committee to select senior research trainees and early-career kidney researchers for funding and training, in the hope that it will be helpful to others who wish to integrate the perspective of people with lived experience into the peer-review process. Sources of information: Other peer-review committees, websites, journal articles, patient partners, Kidney Foundation of Canada Research Council, Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (Can-SOLVE CKD) Patient Council, participants in the 2017 Kidney Foundation of Canada KRESCENT peer-review panel. Methods: We describe our motivation, rationale, guiding principles, plans, feedback, implementation, and response. Key findings: We disseminated a "call for patient partners" 8 weeks before the meeting, seeking patients or their care givers to partner with the KRESCENT peer-review panel; we defined these people with lived experience of kidney disease as patient partners. Eight patient partners came forward and all participated as reviewers. Patient partners first participated in a webinar to learn about the function, structure, and processes of a peer-review committee. They practiced reviewing plain language summaries and giving feedback. In a subsequent teleconference, they shared and discussed their reviews. Plain language summaries were scored, overall, on the same 0-5 quality scale used by scientific reviewers. Three patient reviewers participated in some or all of the 6-hour meeting, which was conducted as usual, for this panel, by teleconference (initially audio only; from 2020 onwards by videoconference). In the meeting, the 2 assigned scientific reviewers first gave their scores, followed by the patient reviewers giving their scores, and discussion (mostly scientific, and conducted in usual scientific language). Scientific reviewers then negotiated a consensus score based on their initial scores, the discussion, patient reviewers' scores and statements, and the scientific officer's notes. Patient reviewers, scientific reviewers, and the Kidney Foundation of Canada (KFOC) were generally positive about the process. The increased length of the meeting (estimated at 1 hour) was generally thought to be acceptable. Patient reviewers also provided feedback on the methods used to incorporate patients into the research under review. These comments were concrete, insightful, and helpful. The patients did not uniformly recommend that basic scientists involve patients in their work. We did not detect bias against preclinical science, work that did not involve patients, or rarer diseases. Some patients found participation inspiring and enlightening. All participants appreciated the idea of patient partners as community witnesses to a group process committed to fairness and supportiveness. We discussed assigning formal meaningful weight to patient reviewers' assessments. Most, but not all, patients thought that the scientific reviewers were ultimately the best judges of the allocation of scarce research resources. Limitations: Patient participants tended to be Caucasian, middle class, and well educated. Because of the difficulties of travel for some people living with or supporting those living with kidney disease, our findings may not generalize fully to peer-review meetings that are conducted face to face. This is explicitly a supportive panel, committed to reviewing junior scientists with kindness as well as rigor; our findings may not generalize to panels conducted differently. We did not use formal qualitative methodology. Implications: Inclusion of patient partners as patient reviewers for the KRESCENT program peer-review panel was feasible, added value for scientific and patient reviewers, and for the funding stakeholders (CIHR, KFOC, and CSN). We were glad that we had taken this step and continue to refine the process with each successive competition.

Motif de la revue: Le KRESCENT (Kidney Research Scientist Core Education and National Training) est un programme national de formation pour les chercheurs en santé rénale financé par la Fondation canadienne du rein (FCR), les Instituts de recherche en santé du Canada (IRSC) et la Société canadienne de néphrologie (SCN). Nous décrivons notre première année d'intégration de partenaires patients dans un comité d'examen scientifique par les pairs, le comité de 2017, visant la sélection de stagiaires de recherche et de chercheurs en santé rénale en début de carrière pour le financement et la formation, dans l'espoir que cela sera utile à ceux qui souhaitent intégrer la perspective des personnes ayant une expérience vécue au processus d'examen par les pairs. Sources: Autres comités d'examen par les pairs, sites Web, articles de revues, partenaires patients, Conseil de recherche de la Fondation canadienne du rein, conseil des patients de Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (CAN-SOLVE CKD), participants au comité d'examen par les pairs de la Fondation canadienne du rein de 2017. Méthodologie: Nous décrivons ce qui a motivé cette étude, notre raisonnement, nos principes directeurs, nos plans, la rétroaction, la mise en œuvre et les réponses. Principaux résultats: Nous avons diffusé un « appel à des partenaires patients ¼ huit semaines avant la réunion pour trouver des patients ou des soignants prêts à collaborer avec le comité d'examen par les pairs de KRESCENT; nous avons défini comme partenaires patients les personnes ayant une expérience vécue de maladie rénale. Huit partenaires patients ont répondu à l'appel et tous ont participé en tant qu'examinateurs. Les partenaires patients ont d'abord participé à un webinaire pour en apprendre davantage sur la fonction, la structure et les processus d'un comité d'examen par les pairs. Ils se sont ensuite entraînés à examiner des résumés en langage simple et à donner des commentaires. Lors d'une téléconférence ultérieure, ils ont partagé et discuté de leurs examens respectifs. Les résumés en langage clair ont été notés, dans l'ensemble, sur la même échelle de qualité de 0 à 5 utilisée par les examinateurs scientifiques. Trois patients examinateurs ont participé à une partie ou à la totalité de la réunion de 6 heures, qui s'est tenue comme d'habitude, pour ce panel, par téléconférence (initialement en audio seulement; par vidéoconférence à partir de 2020). Au cours de la réunion, les deux examinateurs scientifiques désignés ont d'abord donné leurs notes, puis les patients examinateurs ont donné leurs notes, et une discussion a suivi (principalement scientifique, et menée dans le langage scientifique habituel). Les examinateurs scientifiques ont ensuite négocié pour établir une note consensuelle en fonction de leurs notes initiales, de la discussion, des notes et des commentaires des patients examinateurs et des notes de l'agent scientifique.Les patients examinateurs, les examinateurs scientifiques et la Fondation canadienne du rein étaient généralement positifs à l'égard du processus. La durée accrue de la réunion (estimée à 1 heure) a généralement été jugée acceptable. Les patients examinateurs ont également fourni des commentaires sur les méthodes utilisées pour intégrer les patients à la recherche à l'étude. Ces commentaires étaient concrets, pertinents et utiles. Les patients ne recommandent pas uniformément que les scientifiques en recherche fondamentale impliquent les patients dans leur travail. Nous n'avons pas détecté de biais contre la science préclinique, les études qui n'impliquent pas de patients ou les maladies plus rares. Certains patients ont trouvé la participation inspirante et instructive. Tous les participants ont aimé l'idée des partenaires patients comme témoins communautaires d'un processus de groupe engagé dans l'équité et le soutien.Nous avons discuté de l'attribution d'un poids formel significatif aux évaluations des patients examinateurs. La plupart des patients, mais pas tous, étaient d'avis que les examinateurs scientifiques étaient en fin de compte les meilleurs juges de l'allocation des ressources limitées de la recherche. Limites: Les patients participants étaient pour la plupart de race blanche, de classe moyenne et bien éduqués. En raison des difficultés de déplacement pour certaines personnes vivant avec ou soutenant les personnes vivant avec une maladie rénale, nos résultats peuvent ne pas se généraliser entièrement aux réunions d'examen par les pairs menées en personne. Il s'agit essentiellement d'un groupe de soutien, qui s'est engagé à examiner les jeunes chercheurs avec bienveillance et rigueur; nos conclusions peuvent ne pas se généraliser à des groupes de travail menés différemment. Nous n'avons pas utilisé de méthodologie qualitative officielle. Résultats: L'inclusion de partenaires patients comme examinateurs dans un comité d'examen par les pairs du programme KRESCENT s'est avérée réalisable, et une valeur ajoutée pour les examinateurs scientifiques, les patients examinateurs et les parties responsables du financement (IRSC, FCR et SCN). Nous sommes heureux d'avoir franchi cette étape, nous continuons de raffiner le processus à chaque concours successif.

Shared pathobiology identifies AMPK as a therapeutic target for obesity and autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common Mendelian kidney disease, affecting approximately one in 1,000 births and accounting for 5% of end-stage kidney disease in developed countries. The pathophysiology of ADPKD is strongly linked to metabolic dysregulation, which may be secondary to defective polycystin function. Overweight and obesity are highly prevalent in patients with ADPKD and constitute an independent risk factor for progression. Recent studies have highlighted reduced AMP-activated protein kinase (AMPK) activity, increased mammalian target of rapamycin (mTOR) signaling, and mitochondrial dysfunction as shared pathobiology between ADPKD and overweight/obesity. Notably, mTOR and AMPK are two diametrically opposed sensors of energy metabolism that regulate cell growth and proliferation. However, treatment with the current generation of mTOR inhibitors is poorly tolerated due to their toxicity, making clinical translation difficult. By contrast, multiple preclinical and clinical studies have shown that pharmacological activation of AMPK provides a promising approach to treat ADPKD. In this narrative review, we summarize the pleiotropic functions of AMPK as a regulator of cellular proliferation, macromolecule metabolism, and mitochondrial biogenesis, and discuss the potential for pharmacological activation of AMPK to treat ADPKD and obesity-related kidney disease.

Urinary interleukin-9 in youth with type 1 diabetes mellitus.

AIMS: Interleukin-9 (IL-9) attenuates podocyte injury in experimental kidney disease, but its role in diabetic nephropathy is unknown. We sought to relate urinary IL-9 levels to the release of podocyte-derived extracellular vesicles (EVs) in youth with type 1 diabetes. We related urinary IL-9 levels to clinical variables and studied interactions between urinary IL-9, vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) on urinary albumin/creatinine ratio (ACR) a functional measure of podocyte injury. METHODS: We performed an analysis of urine samples and clinical data from a cohort of youth with type 1 diabetes (n = 53). Cytokines were measured using a Luminex platform (Eve Technologies), and nanoscale flow cytometry was employed to quantify urinary podocyte-derived EVs. All urinary measures were normalized to urinary creatinine. RESULTS: Mean age was 14.7 ± 1.6 years, and the mean time from diagnosis was 6.7 ± 2.9 years. Mean HbA1c was 70.3 ± 13.9 mmol/mol, mean ACR was 1.3 ± 1.9 mg/mmol, and mean eGFR was 140.3 ± 32.6 ml/min/1.73 m2. IL-9 was inversely related to podocyte EVs (r = - 0.56, p = 0.003). IL-9 was also inversely related to blood glucose, HbA1C and eGFR (r = - 0.44, p = 0.002; r = - 0.41, p = 0.003; r = - 0.49, p < 0.001, respectively) and positively correlated with systolic BP (r = 0.30, p = 0.04). There was a significant interaction between IL-9, EVs and ACR (p = 0.0143), and the relationship between IL-9 and ACR depended on VEGF (p = 0.0083), TNFα (p = 0.0231) and IL-6 levels (p = 0.0178). CONCLUSIONS: IL-9 is associated with podocyte injury in early type 1 diabetes, and there are complex interactions between urinary IL-9, inflammatory cytokines and ACR.

Dietary Interventions in Autosomal Dominant Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the progressive growth of renal cysts, leading to the loss of functional nephrons. Recommendations for individuals with ADPKD to maintain a healthy diet and lifestyle are largely similar to those for the general population. However, recent evidence from preclinical models suggests that more tightly specified dietary regimens, including caloric restriction, intermittent fasting, and ketogenic diets, hold promise to slow disease progression, and the results of ongoing human clinical trials are eagerly awaited. These dietary interventions directly influence nutrient signaling and substrate availability in the cystic kidney, while also conferring systemic metabolic benefits. The present review focuses on the importance of local and systemic metabolism in ADPKD and summarizes current evidence for dietary interventions to slow disease progression and improve quality of life.

Evaluation of novel glomerular filtration rate estimation equations in adolescents and young adults with type 1 diabetes.

AIMS: Individuals with type 1 diabetes (T1D) are at an increased risk of chronic kidney disease making estimation of glomerular filtration rate (eGFR) an important component of diabetes care. Which eGFR equation is most appropriate to use in patients with T1D during the transition to adult care is unclear. We, therefore, sought to evaluate the performance of five eGFR equations in adolescents and young adults with T1D. METHODS: Measured iohexol-based glomerular filtration rate was compared to the Chronic Kidney Disease and Epidemiology Collaboration (CKD-EPI) eGFR, Chronic Kidney Disease in Children (CKiD) eGFR, and three recently developed age-adjusted versions of these in 53 patients with T1D and preserved GFR using bias, precision, and accuracy. RESULTS: The best performance was found in the sex-dependent CKiD equation (bias: -0.8, accuracy: 11.8 ml/min/1.73 m2). Bias and accuracy (26.4 and 26.8 ml/min/1.73 m2) were worst in the CKD-EPI equation. Age-dependent adjustment improved performance for this equation (bias: 5.3, accuracy: 13.4 ml/min/1.73 m2), but not for the CKiD equation (bias: 15.5, accuracy: 18.8 ml/min/1.73 m2). CONCLUSION: Age-adjustment improved performance for the CKD-EPI equation, but not for the CKiD equation. The sex-adjusted CKiD equation performed best out of all equations.

Follistatin-Like-1 (FSTL1) Is a Fibroblast-Derived Growth Factor That Contributes to Progression of Chronic Kidney Disease.

Our understanding of the mechanisms responsible for the progression of chronic kidney disease (CKD) is incomplete. Microarray analysis of kidneys at 4 and 7 weeks of age in Col4a3-/- mice, a model of progressive nephropathy characterized by proteinuria, interstitial fibrosis, and inflammation, revealed that Follistatin-like-1 (Fstl1) was one of only four genes significantly overexpressed at 4 weeks of age. mRNA levels for the Fstl1 receptors, Tlr4 and Dip2a, increased in both Col4a-/- mice and mice subjected to unilateral ureteral obstruction (UUO). RNAscope® (Advanced Cell Diagnostics, Newark CA, USA) localized Fstl1 to interstitial cells, and in silico analysis of single cell transcriptomic data from human kidneys showed Fstl1 confined to interstitial fibroblasts/myofibroblasts. In vitro, FSTL1 activated AP1 and NFκB, increased collagen I (COL1A1) and interleukin-6 (IL6) expression, and induced apoptosis in cultured kidney cells. FSTL1 expression in the NEPTUNE cohort of humans with focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), and IgA nephropathy (IgAN) was positively associated with age, eGFR, and proteinuria by multiple linear regression, as well as with interstitial fibrosis and tubular atrophy. Clinical disease progression, defined as dialysis or a 40 percent reduction in eGFR, was greater in patients with high baseline FSTL1 mRNA levels. FSTL1 is a fibroblast-derived cytokine linked to the progression of experimental and clinical CKD.

Sex and kidney ACE2 expression in primary focal segmental glomerulosclerosis: A NEPTUNE study.

BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) has been implicated in the pathogenesis of experimental kidney disease. ACE2 is on the X chromosome, and in mice, deletion of ACE2 leads to the development of focal segmental glomerulosclerosis (FSGS). The relationship between sex and renal ACE2 expression in humans with kidney disease is a gap in current knowledge. METHODS: We studied renal tubulointerstitial microarray data and clinical variables from subjects with FSGS enrolled in the Nephrotic Syndrome Study Network (NEPTUNE) study. We compared relationships between ACE2 expression and age, estimated glomerular filtration rate (eGFR), urinary albumin to creatinine ratio (UACR), interstitial fibrosis, tubular atrophy, and genes implicated in inflammation and fibrosis in male and female subjects. RESULTS: ACE2 mRNA expression was lower in the tubulointerstitium of males compared to females (P = 0.0026). Multiple linear regression analysis showed that ACE2 expression was related to sex and eGFR but not to age or treatment with renin angiotensin system blockade. ACE2 expression is also related to interstitial fibrosis, and tubular atrophy, in males but not in females. Genes involved in inflammation (CCL2 and TNF) correlated with ACE2 expression in males (TNF: r = -0.65, P < 0.0001; CCL2: r = -0.60, P < 0.0001) but not in females. TGFB1, a gene implicated in fibrosis correlated with ACE2 in both sexes. CONCLUSIONS: Sex is an important determinant of ACE2 expression in the tubulointerstitium of the kidney in FSGS. Sex also influences the relationships between ACE2, kidney fibrosis, and expression of genes involved in kidney inflammation.

Recent Approaches to Targeting Canonical NFκB Signaling in the Early Inflammatory Response to Renal IRI.

Ischemia reperfusion injury (IRI) is the most common cause of in-hospital AKI and is associated with increased morbidity and mortality. IRI is associated with an early phase of inflammation primarily regulated by the canonical NFκB signaling pathway. Despite recent advances in our understanding of the pathogenesis of IRI, few therapeutic strategies have emerged. The purpose of this manuscript is to review interventions targeting NFκB after IRI.

Comparison of Clinical and Social Characteristics of Canadian Youth Living With Type 1 and Type 2 Diabetes.

OBJECTIVES: Our aim in this study was to describe the clinical and social characteristics of 2 Canadian cohorts of adolescents with diabetes. METHODS: Participants from the Improving renal Complications in Adolescents with type 2 diabetes through REsearch (iCARE) study (n=322) and the Early Determinants of Cardio-Renal Disease in Youth With Type 1 Diabetes (n=199) study were compared. RESULTS: Adolescents were 10 to 18 years of age (mean ± standard deviation: 14.8±2.4 years). The T2DM cohort had a shorter duration of diabetes. Both groups had glycated hemoglobin levels above target. The type 2 diabetes (T2D) cohort was comprised of predominantly Indigenous youth. The type 1 diabetes (T1D) cohort was 58.3% European/Caucasian, with a high proportion (41.7%) of visible minority groups (Afro-Caribbean, Asian/Pacific Islander, Hispanic). The prevalence of obesity, hypertension, left ventricular hypertrophy, albuminuria and hyperfiltration was higher in the T2D cohort. The T1D cohort was more socially and economically advantaged in all 4 dimensions of health inequality. CONCLUSIONS: There are significant differences in clinical and social characteristics of adolescents with T2D and T1D in Canada. Both have inadequate glycemic control with evidence of onset and progression of diabetes-related complications.

Urinary podocyte-derived microparticles in youth with type 1 and type 2 diabetes.

AIMS/HYPOTHESIS: The release of podocyte-derived microparticles into the urine may reflect early kidney injury in diabetes. We measured the urinary excretion of podocyte-derived microparticles in youth with type 1 and type 2 diabetes, and related the values to blood pressure, renal function and blood glucose levels. METHODS: Cross-sectional, exploratory analysis of urine samples and clinical data from youth with type 1 (n = 53) and type 2 (n = 50) diabetes was carried out. Urinary podocyte-derived microparticle numbers, measured by flow cytometry, were assessed in relation to measures of blood glucose levels and renal function. RESULTS: Podocyte-derived microparticle excretion (MPE) normalised to urinary creatinine (MP/UCr) was higher in type 1 vs type 2 diabetes (median [IQR] MP/UCr: 7.88 [8.97] vs 1.84 [8.62]; p < 0.0001), despite the type 2 diabetes group having higher blood pressure (systolic blood pressure, median [range]: 124 [110-154] vs 114 [94-143] mmHg) and higher proportions of microalbuminuria (44.0% vs 13.2%), but shorter time since diabetes diagnosis (median [range]: 1.2 [0.0-7.0] vs 6.4 [2.0-13.9] years), than the type 1 diabetes cohort. MPE in youth with type 1 diabetes was associated with blood glucose (p = 0.01) and eGFR (p = 0.03) but not HbA1c, systolic or diastolic blood pressure or urine albumin/creatinine ratio. After adjustment for age at baseline, duration of diabetes, sex and BMI, the association with eGFR remained significant (p = 0.04). No associations were found between MPE and these clinical variables in youth with type 2 diabetes. CONCLUSIONS/INTERPRETATION: Significant associations between podocyte MPE, blood glucose levels and eGFR were observed in youth with type 1 diabetes but not in those with type 2 diabetes, notwithstanding increased renal pathology in the type 2 diabetes cohort. These findings suggest that podocyte injury differs in the two diabetes cohorts. Graphical abstract.

A Framework to Ensure Patient Partners Have Equal and Contributing Voices Throughout the Research Program Evaluation Process.

PURPOSE OF PROGRAM: Traditionally, peer review was a closed process conducted only by individuals working in the research field. To establish a more integrated and patient-centered approach, one of Canada's largest kidney research networks (Can-SOLVE CKD) has created a Research Operations Committee (ROC) that includes patients as key members. The ROC represents one way for achieving meaningful patient-oriented research (POR). SOURCE OF INFORMATION: Can-SOLVE CKD, a network created as part of the Canadian Institutes of Health Research (CIHR) Strategy for Patient-Oriented Research (SPOR). METHODS: The ROC consists of patients, physicians, scientists, Indigenous partners, experts in research methodology, and a member of Can-SOLVE CKD's operational team. On an annual basis, Can-SOLVE CKD's research teams provide the ROC with a review package, which incorporates information from patient engagement check-in calls and surveys, the project's knowledge translation plan and products, and a progress report written by the project team. The ROC evaluates the review package and provides feedback and recommendations accordingly. KEY FINDINGS: The transparent nature of the process, regular feedback and review, along with an overt accountability and scoring system, has been embraced by both patients and researchers. As a result of the ROC process, the number of patient leads for each project has grown over a 3-year period and more researchers have received POR and cultural sensitivity training. LIMITATIONS: While anecdotal evidence suggests this approach is beneficial for achieving POR, formal mechanisms of evaluation are currently lacking. IMPLICATIONS: This ROC framework ensures patients are active contributors throughout the research process and could be adopted by other organizations to achieve a more patient-centered approach to research.

OBJECTIF DU PROGRAM: L'évaluation par les pairs consiste habituellement en un processus fermé et mené uniquement par des personnes travaillant dans le domaine de la recherche. Pour développer une approche plus intégrée et davantage axée sur les patients, un des plus importants réseaux canadiens de recherche sur les maladies rénales (Can-SOLVE CKD) a créé un comité de gestion de la recherche (CGR) où les patients sont des membres à part entière. Une approche qui vise la conduite d'activités de recherches significatives et davantage orientées vers le patient. SOURCE: Can-SOLVE CKD, un réseau créé dans le cadre de la Stratégie de recherche axée sur le patient (SRAP) des Instituts de recherche en santé du Canada (IRSC). MÉTHODOLOGIE: Le CGR rassemble des patients, des médecins, des chercheurs, des partenaires autochtones, des experts en méthodologie de recherche et un membre de l'équipe d'intervention de Can-SOLVE CKD. Une fois par année, l'équipe de recherche de Can-SOLVE CKD fournit au CGR un dossier d'examen. Ce dossier contient les informations recueillies lors d'appels ou de sondages vérifiant l'engagement des patients, le plan d'application des connaissances du projet et ses résultats, de même qu'un rapport périodique rédigé par l'équipe responsable du projet. Le CGR évalue ce dossier et émet ses commentaires et recommandations. PRINCIPAUX RÉSULTATS: La transparence du processus, la rétroaction et la révision sur une base régulière, de même que les systèmes de responsabilité et de notation ouverts ont été adoptés tant par les patients que par les chercheurs. Grâce à ce processus, le nombre de patients candidats pour chaque projet a augmenté sur une période de trois ans, et davantage de chercheurs ont reçu une formation sur les réalités culturelles et la pratique d'activités de recherche axées sur le patient. LIMITES: Bien que des preuves anecdotiques suggèrent que cette approche soit bénéfique à la conduite de recherches axées sur le patient, des mécanismes formels pour son évaluation manquent toujours. CONCLUSION: Le cadre proposé par le CGR assure une contribution active des patients tout au long du processus de recherche. Ce program pourrait être adopté par d'autres organizations et permettre la réalisation d'activités de recherche davantage axées sur le patient.

Inhibition of BRD4 Reduces Neutrophil Activation and Adhesion to the Vascular Endothelium Following Ischemia Reperfusion Injury.

Renal ischemia reperfusion injury (IRI) is associated with inflammation, including neutrophil infiltration that exacerbates the initial ischemic insult. The molecular pathways involved are poorly characterized and there is currently no treatment. We performed an in silico analysis demonstrating changes in NFκB-mediated gene expression in early renal IRI. We then evaluated NFκB-blockade with a BRD4 inhibitor on neutrophil adhesion to endothelial cells in vitro, and tested BRD4 inhibition in an in vivo IRI model. BRD4 inhibition attenuated neutrophil adhesion to activated endothelial cells. In vivo, IRI led to increased expression of cytokines and adhesion molecules at 6 h post-IRI with sustained up-regulated expression to 48 h post-IRI. These effects were attenuated, in part, with BRD4 inhibition. Absolute neutrophil counts increased significantly in the bone marrow, blood, and kidney 24 h post-IRI. Activated neutrophils increased in the blood and kidney at 6 h post-IRI and remained elevated in the kidney until 48 h post-IRI. BRD4 inhibition reduced both total and activated neutrophil counts in the kidney. IRI-induced tubular injury correlated with neutrophil accumulation and was reduced by BRD4 inhibition. In summary, BRD4 inhibition has important systemic and renal effects on neutrophils, and these effects are associated with reduced renal injury.

Kidney ACE2 expression: Implications for chronic kidney disease.

Angiotensin-converting enzyme 2 (ACE2) has been implicated in the pathogenesis of chronic kidney disease (CKD) and is a membrane receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease (COVID-19), whereas transmembrane protease, serine 2 (TMPRSS2) is involved in viral attachment. Together, tissue expression of ACE2 and TMPRSS2 may determine infection. Sex, age, body mass index (BMI), and CKD are clinical risk factors for COVID-19 severity, but the relationships between kidney ACE2 and TMPRSS2 expression and these clinical variables are unknown. Accordingly, we obtained renal tubulointerstitial and glomerular microarray expression data and clinical variables from healthy living donors (HLD) and patients with CKD from the European Renal cDNA Bank. ACE2 expression was similar in the tubulointerstitium of the two groups, but greater in females than males in HLD (P = 0.005) and CKD (P < 0.0001). ACE2 expression was lower in glomeruli of CKD patients compared to HLD (P = 0.0002) and lower in males than females. TMPRSS2 expression was similar in the tubulointerstitium but lower in glomeruli of CKD patients compared to HLD (P < 0.0001). There was a strong relationship between ACE2 and TMPRSS2 expression in the glomerulus (r = 0.51, P < 0.0001). In CKD, there was a relationship between tubulointerstitial ACE2 expression and estimated glomerular filtration rate (r = 0.36, P < 0.0001) and age (r = -0.17, P = 0.03), but no relationship with BMI. There were no relationships between TMPRSS2 expression and clinical variables. Genes involved in inflammation (CCL2, IL6, and TNF) and fibrosis (COL1A1, TGFB1, and FN1) were inversely correlated with ACE2 expression. In summary, kidney expression of ACE2 and TMPRSS2 differs in HLD and CKD. ACE2 is related to sex and eGFR. ACE2 is also associated with expression of genes implicated in inflammation and fibrosis.

An evaluation of renin-angiotensin system markers in youth with type 2 diabetes and associations with renal outcomes.

AIMS/HYPOTHESIS: Youth with type 2 diabetes (T2D) have high rates of obesity, hypertension and suboptimal glycemic control. We hypothesized that renin-angiotensin system (RAS) activation is present in youth with T2D and associated with poor glycemic control and renal outcomes. METHODS: Cross-sectional analysis of 183 youth with T2D and 100 controls from the Improving renal Complications in Adolescents with T2D through REsearch cohort. Diabetes youth stratified by urine albumin:creatinine ratio (ACR) < or ≥2 mg/mmol. RAS levels measured with enzyme-linked immunosorbent assay (ELISA) and enzyme activities by synthetic substrates. In T2D, levels log transformed and Tobit linear regressions evaluated for associations with hemoglobin A1c (HbA1c), mean arterial pressure (MAP), estimated glomerular filtration rate (eGFR), ACR. RESULTS: Youth were 14 to 15 years, with diabetes duration 1.7 to 1.8 years; 21.3% albuminuria. Serum: differences in plasma renin activity (<0.0001), and angiotensin converting enzyme (ACE) activity (P = .003) in T2D vs controls. Urine: higher ACE activity and ACE2 protein/activity (all P < .0001) in T2D, higher levels in T2D with albuminuria. Multivariable regressions: higher serum ACE activity (ß = 0.03, SE 0.01;P < .01), urine ACE activity (ß = 0.44, SE 0.18;P < .01), ACE2 (ß = 0.51, SE 0.19;P < .01) positively associated with HbA1c; urine angiotensinogen (AGT) negatively associated (ß = -0.28 [SE 0.06;P < .01]). Higher serum aldosterone (ß = 0.11 [SE 0.04;P < .01]) and urine AGT (ß = 0.32 [SE 0.07;P < .01]) significantly associated with ACR and urine ACE2 (ß = 0.21 [SE 0.13;P < .03]). No associations between RAS markers and eGFR/MAP. CONCLUSIONS/INTERPRETATION: RAS activation present in youth with T2D and associated with higher HbA1c. Higher serum aldosterone and urine AGT associated with albuminuria. The prognostic significance of the combined effect of glycemia and RAS activation on renal outcomes requires additional investigation.