Cardiovascular Risk in Patients With Glomerular Disease: A Narrative Review of the Epidemiology, Mechanisms, Management, and Patient Priorities.

Purpose of review: Cardiovascular (CV) disease is a major cause of morbidity and mortality for patients with glomerular disease. Despite the fact that mechanisms underpinning CV disease risk in this population are likely distinct from other forms of kidney disease, treatment and preventive strategies tend to be extrapolated from studies of patients with undifferentiated chronic kidney disease (CKD). There is an unmet need to delineate the pathophysiology of CV disease in patients with glomerular disease, establish unique risk factors, and identify novel therapeutic targets for disease prevention. The aims of this narrative review are to summarize the existing knowledge regarding the epidemiology, molecular mechanisms, and management of CV disease in patients with common glomerular disease, highlight the patient perspective, and propose specific areas for future study. Sources of information: The literature for this narrative review was accessed using common research search engines, including PubMed, PubMed Central, Medline, and Google Scholar. Information for the patient perspective section was collected through iterative discussions with a patient partner. Methods: We reviewed the epidemiology, molecular mechanisms of disease, management approaches, and the patient perspective in relation to CV disease in patients with glomerulopathies. Throughout, we have highlighted the current knowledge and have discussed future research approaches, both clinical and translational, while integrating the patient perspective. Key findings: Patients with glomerular disease have significant CV disease risk driven by multifactorial, molecular mechanisms originating from their glomerular disease but complicated by existing comorbidities, kidney disease, and medication side effects. The current approach to risk stratification and treatment relies heavily on existing data from CKD patients, but this may not always be appropriate given the unique pathophysiology and mechanisms associated with CV disease risk in patients with glomerular disease. We highlight the need for ongoing glomerular disease-focused studies aimed to better delineate CV disease risk, while integrating the patient perspective. Limitations: This is a narrative review and does not represent a comprehensive and systematic review of the literature.

Motif de la revue: Les maladies cardiovasculaires sont une cause majeure de morbidité et de mortalité chez les patients atteints d'une maladie glomérulaire. Bien que les mécanismes qui sous-tendent le risque de maladie cardiovasculaire dans cette population sont probablement distincts des autres formes de néphropathies, le traitement et les stratégies préventives ont tendance à être extrapolés à partir d'études portant sur des patients atteints d'insuffisance rénale chronique indifférenciée. Il existe ainsi un besoin de délimiter la physiopathologie des maladies cardiovasculaires chez les patients atteints d'une maladie glomérulaire, d'établir les facteurs de risque propres à la maladie glomérulaire et d'identifier de nouvelles cibles thérapeutiques pour la prévenir. Les objectifs de cette revue narrative sont de résumer les connaissances existantes concernant l'épidémiologie, les mécanismes moléculaires et la prise en charge des maladies cardiovasculaires chez les patients atteints d'une maladie glomérulaire commune, de mettre en évidence le point de vue des patients et de proposer des domaines précis pour de futures études. Sources de l'information: La documentation a été consultée par le biais des moteurs de recherche courants, notamment PubMed, PubMed Central, Medline et Google Scholar. Les points de vue des patients ont été recueillis au moyen de discussions itératives avec un patient partenaire. Méthodologie: Nous avons examiné l'épidémiologie et les mécanismes moléculaires de la maladie, les approches de prise en charge et la perspective des patients en lien avec les maladies cardiovasculaires chez les patients atteints d'une maladie glomérulaire. Nous avons fait état des connaissances actuelles et discuté des approches à envisager pour les recherches futures, tant cliniques que translationnelles, tout en intégrant la perspective du patient. Principales observations: Les patients atteints d'une maladie glomérulaire présentent un risque significatif de maladie cardiovasculaire associé à des mécanismes moléculaires multifactoriels provenant de la maladie glomérulaire elle-même. Ce risque est compliqué par les comorbidités existantes, la néphropathie et les effets secondaires des médicaments. L'approche actuelle de stratification du risque et de traitement repose en grande partie sur les données existantes pour les patients atteints d'insuffisance rénale chronique; cette approche pourrait ne pas toujours convenir, compte tenu de la physiopathologie unique et des mécanismes associés au risque de maladie cardiovasculaire chez les patients atteints d'une maladie glomérulaire. Nos résultats mettent en lumière le besoin d'études continues, axées sur les maladies glomérulaires, qui visent à mieux cerner le risque de maladies cardiovasculaires chez ces patients, tout en intègrant leur point de vue. Limites: Il s'agit d'une revue narrative; cette étude ne constitue pas une revue exhaustive et systématique de la littérature.

The ongoing impact of obesity on childhood hypertension.

Obesity rates among children have been steadily rising over the past several decades. This epidemic has been accompanied by an increase in the prevalence of childhood hypertension, with children in low- and middle-income countries being affected to the same extent as children in high-income countries. This review will examine the trends in childhood blood pressure and the relationship between excess body weight and the development of hypertension. In addition, distinct mechanisms of obesity-related hypertension will be discussed. There will be an emphasis on recent studies conducted since the publication of new guidelines by the American Academy of Pediatrics in 2017 which resulted in the adoption of lower normative blood pressure cutoffs. The overall intent of this review is to provide the reader with an understanding of the ongoing impact, and complexities, of obesity-related hypertension.

Hypertension in pediatric kidney transplantation.

Arterial hypertension (HTN) in children after kidney transplantation is an important risk factor not only for graft loss but also for cardiovascular morbidity and mortality. The prevalence of posttransplant HTN ranges between 60% and 90%. The etiology of posttransplant HTN is multifactorial and includes residual chronic native kidney disease, immunosuppressive therapy, and chronic allograft dysfunction among other causes. Clinic blood pressure (BP) should be measured at each outpatient visit. However, ambulatory blood pressure monitoring (ABPM) is the gold standard method for BP evaluation in children after kidney transplantation, as it often reveals masked and nocturnal HTN; given this, it should be regularly performed in each transplanted child. All classes of antihypertensive drugs are used in the treatment of posttransplant HTN because it has never been proven that one class is better than another. However, in several retrospective studies, the use of calcium channel blockers is associated with better graft function. The optimal target BP for transplanted children is still a matter of debate; it is recommended to target the same BP as for healthy children, that is, <95th percentile. Control of HTN in transplanted children remains poor - only 20%-50% of treated children have normal BP. There is a great potential for improvement of antihypertensive treatment that could potentially result in improvement of both graft and patient survival in children after kidney transplantation.

Impact of acute moderate-intensity aerobic exercise on circulating extracellular vesicles in pregnant and non-pregnant women.

Exercise improves cardiovascular and metabolic health in pregnancy and may represent a non-pharmacological approach to improving pregnancy outcomes. Extracellular vesicles (EVs) are emerging biomarkers of endothelial dysfunction and offer the potential for evaluating vascular health non-invasively during pregnancy. The purpose of this study was to investigate changes in circulating EV levels after an acute bout of moderate-intensity aerobic exercise in healthy pregnant and non-pregnant women. We studied plasma samples from pregnant (N = 13, 13-28 weeks) and non-pregnant (N = 17) women. A pre-exercise blood sample was obtained followed by a 30 min bout of moderate-intensity treadmill-based exercise. Immediately following the exercise, a post-exercise blood draw was collected. Large EVs were isolated from plasma by differential centrifugation and characterized by Western blot and electron microscopy. We quantified circulating EVs by nanoscale flow cytometry. Endothelial EVs were identified as VE-Cadherin+, platelet EVs as CD41+, and leukocyte EVs as CD45+ events. Acute exercise was associated with a significant reduction in levels of circulating endothelial EVs in the non-pregnant group (p = 0.0232) but not in the pregnant group (p = 0.2734). A greater proportion of non-pregnant women (13/17, 76.47%) exhibited a reduction in endothelial EVs compared with their pregnant counterparts (4/13, 30.76%, p < 0.05). We also observed a positive association between measures of fitness (average speed) and baseline levels of platelet (r = 0.5816, p = 0.0159) and total EVs (r = 0.5325, p = 0.0296) in the non-pregnant group but not in pregnant individuals. Collectively, our study highlights that after a matched acute exercise, changes to circulating EV levels differ depending on pregnancy status.

Advancing Discovery Research in Nephrology in Canada: A Conference Report From the 2021 Molecules and Mechanisms Mediating Kidney Health and Disease (M3K) Scientific Meeting and Investigator Summit.

Purpose of conference: New discoveries arising from investigations into fundamental aspects of kidney development and function in health and disease are critical to advancing kidney care. Scientific meetings focused specifically on fundamental biology of the kidney can facilitate interactions, support the development of collaborative groups, and accelerate translation of key findings. The Canadian fundamental kidney researcher community has lacked such a forum. On December 3 to 4, 2021, the first Molecules and Mechanisms Mediating Kidney Health and Disease (M3K) Scientific Meeting and Investigator Summit was held to address this gap with the goal of advancing fundamental kidney research nationally. The meeting was held virtually and was supported by a planning and dissemination grant from the Canadian Institutes of Health Research. Attendees included PhD scientists, nephrology clinician scientists, engineers, industry representatives, graduate students, medical residents, and fellows. Sources of information: This report was prepared from the scientific program, registration numbers, and details obtained from the online platform WHOVA, and summaries written by organizers and participants of the 2021 meeting. Methods: A 21-person team, consisting of the organizing committee members and participants from the meeting, was assembled. Key highlights of the meeting and future directions were identified and the team jointly assembled this report. Key findings: Participation in the meeting was strong, with more than 140 attendees across a range of disciplines. The program featured state-of-the-art presentations on diabetic nephropathy, the immune system, kidney development, and fibrosis, and was heavily focused on trainee presentations. The moderated "Investigator Summit" identified key barriers to research advancement and discussed strategies for overcoming them. These included establishment of a pan-Canadian fundamental kidney research network, development of key resources, cross-pollination with clinical nephrology, better reintegration into the Canadian Society of Nephrology, and further establishment of identity and knowledge translation. Limitations and implications: The 2021 M3K meeting represented a key first step in uniting fundamental kidney researchers in Canada. However, it was universally agreed that regular meetings were necessary to sustain this momentum. The proceedings of this meeting and future actions to sustain the M3K Scientific Meeting and Investigator Summit are presented in this article.

Objectif de la conférence: De nouvelles découvertes découlant des enquêtes sur les aspects fondamentaux du développement et de la fonction des reins en santé ou malades sont essentielles pour faire progresser les soins rénaux. Les réunions scientifiques axées spécifiquement sur la biologie fondamentale du rein peuvent faciliter les interactions, appuyer le développement de groupes de collaboration et accélérer l'application des principaux résultats. La communauté canadienne des chercheurs fondamentaux en néphrologie a manqué d'un tel forum. Les 3 et 4 décembre 2021, le premier Sommet des chercheurs et la réunion scientifique M3K (Molecules and Mechanisms Mediating Kidney Health and Disease) sur les molécules et les médiateurs de la santé et des maladies rénales ont eu lieu pour combler cette lacune; l'objectif était de faire progresser la recherche fondamentale en néphrologie à l'échelle nationale. La réunion s'est tenue virtuellement et était financée par une subvention de planification et de diffusion des Instituts de recherche en santé du Canada. Des doctorants, cliniciens-chercheurs en néphrologie, ingénieurs, représentants de l'industrie, étudiants diplômés, résidents en médecine et en surspécialisation figuraient parmi les participants. Sources: Ce rapport a été préparé à partir du program scientifique, des informations et des numéros d'inscription tirés de la plateforme en ligne WHOVA, et des résumés rédigés par les organisateurs et les participants à la réunion de 2021. Méthodologie: Une équipe de 20 personnes composée de membres du comité organisateur et de participants à la réunion a été formée. Les principaux points saillants de la réunion et les orientations futures ont été déterminés, puis l'équipe a rédigé conjointement le présent rapport. Principaux résultats: La réunion s'est avérée un succès; plus de 140 personnes provenant d'un large éventail de disciplines y ont participé. Le program comprenait des présentations de pointe sur la néphropathie diabétique, le système immunitaire, le développement des reins et la fibrose, et était fortement axé sur des présentations par des stagiaires. Le « Sommet des chercheurs ¼, animé par un modérateur, a permis de déterminer les principaux obstacles à l'avancement de la recherche et de discuter des stratégies pour les surmonter. Ces dernières incluent notamment la création d'un réseau pancanadien de recherche fondamentale en néphrologie, le développement de ressources clés, la pollinisation croisée avec la néphrologie clinique, une « meilleure réintégration dans la Société canadienne de néphrologie ¼ et la poursuite de l'établissement de l'identité et de l'application des connaissances. Limites et implications: La réunion M3K de 2021 a constitué une première étape clé dans l'unification des chercheurs fondamentaux en néphrologie au Canada. On a cependant universellement convenu que des réunions régulières étaient nécessaires pour maintenir cet élan. Le compte rendu de cette réunion ainsi que les actions futures pour soutenir la réunion scientifique M3K et le Sommet des chercheurs sont présentés dans le présent article.

Clinical presentation and management of nephrotic syndrome in the first year of life: A report from the Pediatric Nephrology Research Consortium.

Background and objectives: Nephrotic syndrome (NS) in the first year of life is called congenital (CNS) if diagnosed between 0-3 months, or infantile (INS) if diagnosed between 3-12 months of age. The aim of this study was to determine if there were clinically meaningful differences between CNS and INS patients, regarding clinical presentation, management and outcomes. Design setting participants and measurements: Eleven Pediatric Nephrology Research Consortium sites participated in the study, using IRB-approved retrospective chart reviews of CNS and INS patients born between 1998 and 2019. Data were collected on patient characteristics, pertinent laboratory tests, provided therapy, timing of unilateral/bilateral nephrectomy and initiation of renal replacement therapy (RRT). Results: The study included 69 patients, 49 with CNS and 20 with INS, with a median age at diagnosis of 1 and 6 months, respectively. Management for the two groups was similar regarding nutrition, thyroxin supplementation, immunoglobulin administration, and thrombosis prophylaxis. Within the first 2 months after diagnosis, daily albumin infusions were used more often in CNS vs. INS patients (79 vs. 30%; p = 0.006), while weekly infusions were more common in INS patients (INS vs. CNS: 50 vs. 3%; p = 0.001). During the 6 months preceding RRT, albumin infusions were more frequently prescribed in CNS vs. INS (51 vs. 15%; p = 0.007). Nephrectomy was performed more often in CNS (78%) than in INS (50%; p = 0.02). End-stage kidney disease tended to be more common in children with CNS (80%) vs. INS (60%; p = 0.09). Conclusion: Compared to INS, patients with CNS had a more severe disease course, requiring more frequent albumin infusions, and earlier nephrectomy and RRT. Despite center-specific variations in patient care, 20-40% of these patients did not require nephrectomy or RRT.

Blood pressure variability in children with obesity and sleep-disordered breathing following positive airway pressure treatment.

Obese youth with sleep-disordered breathing are treated with positive airway pressure to improve sleep and cardiovascular status. While improvements in sleep parameters have been confirmed, a study by Katz et al. showed no major improvement in ambulatory blood pressure. The aim of this ancillary study was to analyze short-term blood pressure variability, following positive airway pressure treatment, as a more sensitive marker of cardiovascular health. We analyzed 24-h blood pressure variability data in 17 children, taken at baseline and after 12 months of treatment. These data were derived from an already published prospective, multicenter cohort study conducted in 27 youth (8-16 years) with obesity who were prescribed 1-year of positive airway pressure for moderate-severe sleep-disordered breathing. Significant decreases were found in 24 h systolic blood pressure (p = 0.040) and nighttime diastolic blood pressure (p = 0.041) average real variability, and diastolic blood pressure (p = 0.035) weighted standard deviation. Significant decreases were noted in nighttime diastolic blood pressure time rate variability (p = 0.007). Positive airway pressure treatment resulted in a significant decrease in blood pressure variability, suggesting a clinically significant improvement of sympathetic nerve activity in youth with obesity and sleep-disordered breathing. IMPACT: Cardiovascular variability, as measured by blood pressure variability, is improved in children following positive airway pressure treatment. Our novel findings of improved blood pressure time rate variability are the first described in the pediatric literature. Future studies aimed at analyzing target organ damage in this patient population will allow for a better understanding as to whether alterations in blood pressure variability translate to decreasing target organ damage in children, as seen in adults.

Diastolic hypertension is associated with proteinuria in pediatric patients.

BACKGROUND AND AIMS: Blood pressure lability has been observed in certain cohorts of pediatric patients with variable degrees of proteinuria; however, the impact of proteinuria on blood pressure is not fully elucidated. The objective of our study was to analyze blood pressure and heart rate in pediatric patients with proteinuria. METHODS: We performed a retrospective chart review of patients (age 1-18) diagnosed with idiopathic nephrotic syndrome, with varying degrees of proteinuria. Blood pressure and heart rate data were analyzed in relation to anthropometric and biochemical parameters. A total of 72 urine sample analyses, along with associated blood pressure measurements, were obtained from the charts of 33 children (males = 25). RESULTS: Diastolic blood pressure Z-scores were significantly higher in proteinuric patients (urine protein/creatinine >0.02 g/mmol) compared to non-proteinuric patients (P = .006; Cohen-d 0.97 [0.41; 1.53]). Systolic blood pressure was also significantly higher in proteinuric patients (P = .04), but with a less significant effect size (Cohen-d 0.54 [-0.002; 1.08]). Proteinuria (>0.02 g/mmol) was the most significant predictor of diastolic (ß = .79, P = .04), but not systolic blood pressure elevation on multivariate analysis. CONCLUSIONS: We observed a disproportionate increase in diastolic blood pressure vs systolic blood pressure in patients with proteinuria.

Acute Rheumatic Fever: A Disease of the Past?

Introduction. Acute rheumatic fever (ARF) is a manifestation of the nonsuppurative sequelae of Streptococcus pyogenes infection. Herein, two cases of ARF are presented to highlight that this disease is present in urban cities, can be diagnosed in otherwise healthy children, and that its diagnosis may be challenging, or marred with confounders, leading to delays in diagnosis. Case Report. Two unrelated children, age 7 and 9, presented to an urban hospital in Canada with unique manifestations of ARF. Diagnosis of ARF in the first patient was interrupted by a course of steroids which masked symptoms leading to therapeutic delays. The second patient presented with facial droop and symptoms thought to be viral, thus leading to misdiagnosis as Bell's palsy. Discussion/Conclusion. ARF is more common in underserviced and marginalized populations, which may lead clinicians in urban centers to overlook signs or symptoms suggestive of ARF because they no longer see this condition routinely, or they believe it is a disease of the past.

Extracellular Vesicles: Cell-Derived Biomarkers of Glomerular and Tubular Injury.

Extracellular vesicles (EVs) are important mediators of intercellular communication. Since EVs are also released during pathological conditions, there has been considerable interest in their potential as sensitive biomarkers of cellular stress and/or injury. In the context of kidney disease, urinary EVs are promising indicators of glomerular and tubular damage. In the present review we discuss the role of urinary EVs in kidney health and disease. Our focus is to explore urinary large EVs (lEVs, often referred to as microparticles or microvesicles) as direct and noninvasive early biomarkers of renal injury. In this regard, studies have been demonstrating altered levels of urinary lEVs, especially podocyte-derived lEVs, preceding the decrease of renal function assessed by classical markers. In addition, we discuss the role of small EVs (sEVs, often referred to as exosomes) and their contents in kidney pathophysiology. Even though results concerning the production of sEVs during diseased conditions are varied, there has been a consensus on the importance of urinary sEV content assessment in kidney disease. These mediators, including EV-released miRNAs and mRNAs, are responsible for EV-mediated signaling in the regulation of renal cellular homeostasis, pathogenesis and regeneration. Finally, steps necessary for the validation of EVs as reliable markers will be discussed.

Chronic, Gross Hematuria Caused by Idiopathic Ureteric Stricture.

An otherwise healthy, 10-year-old boy presented with chronic, gross hematuria. This persisted daily for 5 years despite extensive multidisciplinary workup with renal biopsy and resulted in severe iron deficiency anemia. The extensive workup and requirement for routine follow-up, investigations, and procedures led to significant psychosocial distress for the patient. Initially, it was thought the patient had a nutcracker phenomenon, but on closer inspection of his ureters, an idiopathic, unilateral ureteric stricture was discovered and, after 8 weeks of stenting, resulted in complete resolution of the hematuria. Importantly, the patient's psychosocial distress resolved after resolution of the hematuria and with the closure that came with a diagnosis.

Chalcogenopyrylium dyes as differential modulators of organic anion transport by multidrug resistance protein 1 (MRP1), MRP2, and MRP4.

Multidrug resistance proteins (MRPs) mediate the ATP-dependent efflux of structurally diverse compounds, including anticancer drugs and physiologic organic anions. Five classes of chalcogenopyrylium dyes (CGPs) were examined for their ability to modulate transport of [(3)H]estradiol glucuronide (E(2)17ßG; a prototypical MRP substrate) into MRP-enriched inside-out membrane vesicles. Additionally, some CGPs were tested in intact transfected cells using a calcein efflux assay. Sixteen of 34 CGPs inhibited MRP1-mediated E(2)17ßG uptake by >50% (IC50 values: 0.7-7.6 µM). Of 9 CGPs with IC50 values ≤2 µM, two belonged to class I, two to class III, and five to class V. When tested in the intact cells, only 4 of 16 CGPs (at 10 µM) inhibited MRP1-mediated calcein efflux by >50% (III-1, V-3, V-4, V-6), whereas a fifth (I-5) inhibited efflux by just 23%. These five CGPs also inhibited [(3)H]E(2)17ßG uptake by MRP4. In contrast, their effects on MRP2 varied, with two (V-4, V-6) inhibiting E(2)17ßG transport (IC(50) values: 2.0 and 9.2 µM) and two (V-3, III-1) stimulating transport (>2-fold), whereas CGP I-5 had no effect. Strikingly, although V-3 and V-4 had opposite effects on MRP2 activity, they are structurally identical except for their chalcogen atom (Se versus Te). This study is the first to identify class V CGPs, with their distinctive methine or trimethine linkage between two disubstituted pyrylium moieties, as a particularly potent class of MRP modulators, and to show that, within this core structure, differences in the electronegativity associated with a chalcogen atom can be the sole determinant of whether a compound will stimulate or inhibit MRP2.

Chalcogenopyrylium compounds as modulators of the ATP-binding cassette transporters P-glycoprotein (P-gp/ABCB1) and multidrug resistance protein 1 (MRP1/ABCC1).

Twenty-seven chalcogenopyrylium derivatives varying in the heteroatom of the pyrylium core and substituents at the 2-, 4-, and 6-positions were examined for their effect on human MRP1-mediated uptake of tritiated estradiol glucuronide into inside-out membrane vesicles, their affinity for and ability to stimulate the ATPase activity of purified human P-glycoprotein (P-gp)-His(10), and their ability to promote uptake of calcein AM and vinblastine in multidrug-resistant cells. Differences in their effects on MRP1 and P-gp activity were noted, and a second set of thiopyrylium compounds with systematic substituent changes was examined to refine these differences further. Derivatives with tert-butyl substituents in the 2- and 6-positions had the lowest inhibitory activity toward both transporters. Derivatives with thioamide functionality in the 4-position were more active against MRP1 than derivatives with amide functionality. Conversely, derivatives with amide functionality in the 4-position were more active in P-gp than derivatives with thioamide functionality.