P2Y2R and Cyst Growth in Polycystic Kidney Disease
Deletion of P2Y2R and pharmacological antagonism of purinergic signaling significantly reduced cyst growth in an orthologous PKD mouse model. P2Y2R was expressed in cysts of human PKD nephrectomies, which makes P2Y2R a reasonable target for treatment of PKD.
KEY FINDINGS: P2Y2R was significantly expressed in human and mouse polycystic kidneys. Deletion and antagonism of P2Y2R reduced cyst enlargement in an ADPKD mouse model.
BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by multiple bilateral kidney cysts that gradually enlarge, resulting in a decline in kidney function. Cyst growth is significantly driven by ATP-dependent chloride secretion mediated by the ion channel TMEM16A. This pathway is further augmented in advanced stages of the disease by hypoxia and activation of hypoxia-inducible factor (HIF)-1α. The mechanisms by which ATP leads to activation of TMEM16A and how HIF-1α contributes to cyst growth in vivo have remained elusive.
DETAILS: Mice with an inducible tubule-specific deletion of Pkd1 were compared with mice with an additional codeletion of the purinergic receptor P2y2r. Furthermore, animals were challenged by pharmacological activation of HIF-1α and Pkd1-deficient mice were treated with suramin, an antagonist of purinergic signaling. In addition, expression of P2Y2R, TMEM16A, and HIF-1α was analyzed in nephrectomy samples from 27 patients with ADPKD. Genetic deletion of P2y2r significantly inhibited cyst growth in vivo. In addition, aggravation of the polycystic phenotype mediated by pharmacological activation of HIF-1α was reduced by deletion of P2y2r. Application of suramin to pharmacologically inhibit purinergic signaling also suppressed cyst enlargement in vivo. Analysis of kidney samples from 27 patients with ADPKD revealed significant expression of P2Y2R at the luminal site of the cyst-lining epithelium.
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Source: Kraus, A., Skoczynski, K., Brotsch. M., et al. (2024). P2Y2R and Cyst Growth in Polycystic Kidney Disease. Journal of the American Society of Nephrology. 2024; 35(10):p 1351-1365. Published: October, 2024. DOI: 10.1681/ASN.0000000000000416.
A Simple Blood Test Warns of Possible Cardiometabolic Complications for Children With Obesity
Scientists from the University of Copenhagen have detected lipid biomarkers in children and teenagers with obesity that indicate an increased risk of developing type 2 diabetes, liver and heart disease as adults. A one-year lifestyle intervention lowered the levels of these lipid biomarkers, which demonstrates the importance of early intervention for children with obesity.
KEY FINDINGS: Scientists from the University of Copenhagen have detected lipid biomarkers in children and teenagers with obesity that indicate an increased risk of developing type 2 diabetes, liver and heart disease as adults. A one-year lifestyle intervention lowered the levels of these lipid biomarkers, which demonstrates the importance of early intervention for children with obesity.
BACKGROUND: The number of children and teens with obesity is increasing worldwide, with over 250 million expected to be affected by 2030. It is a major public health crisis, as children with obesity risk developing insulin resistance, fatty liver, and high blood pressure, which may lead to diseases such as cardiovascular disease, type 2 diabetes and liver disease, later in life.
DETAILS: Scientists think these diseases can be triggered by changes in the body's lipids -- a wide range of fats and oils in the body including triglycerides and cholesterol that serve many purposes including energy storage and cellular signalling. But it is still not well understood how lipid species change in children with obesity, and how they are linked to early cardiometabolic complications.
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Now, scientists at the University of Copenhagen have discovered that lipid species linked to cardiometabolic disease in adults are strongly associated with cardiometabolic risk factors in children and teenagers with obesity. The findings could pave the way for tests that serve as an early warning system for cardiometabolic disease.
"Our study shows that the impact of cardiometabolic associated lipid species emerges early in life in children with obesity, particularly affecting liver function and glucose metabolism. These risk lipid species could potentially be explored further as biomarkers for diagnosing or predicting cardiometabolic risk in children at high risk, offering new insights for early detection and intervention," says Postdoc Yun Huang from the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, and co-first author of the study in Nature Medicine.
Early intervention reverses cardiometabolic disease risk
The scientists made their discoveries by drawing on the HOLBAEK Study biobank of more than 4,000 children with and without obesity. at the Children's Obesity Clinic at Holbaek Hospital. Together with scientists at Steno Diabetes Center Copenhagen, they harnessed powerful mass spectrometry technology to map hundreds of individual lipid species, each with distinct structures and functions, providing a detailed picture of lipid metabolism. By analyzing the differences in the lipid profiles of 958 children with overweight or obesity and 373 who had normal weight, they gained deep insight into obesity altered lipid profiles and their link to cardiometabolic risk, and the ability to detect excessive fat in the liver.
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Source: University of Copenhagen - The Faculty of Health and Medical Sciences (2024). A Simple Blood Test Warns of Possible Cardiometabolic Complications for Children With Obesity. ScienceDaily. 2024; Published: September 20, 2024. DOI: 10.1038/s41591-024-03279-x.
Visceral Adiposity and Progression of ADPKD
Visceral abdominal adiposity quantified by MRI in the coronal plane using a deep learning segmentation model can be used as an index of axial segmentation in patients with ADPKD. Higher visceral abdominal adiposity was independently associated with faster kidney growth in patients with relatively early-stage ADPKD at high risk of rapid progression.
Summary
A Cohort Study of Patients From the TEMPO 3:4 Trial
[Posted 3/Sep/2024]
AUDIENCE: Nephrology, Internal Medicine
KEY FINDINGS: Visceral adiposity that can be quantified by MRI in the coronal plane using a deep learning segmentation model independently associates with more rapid kidney growth and improves classification of rapid progression in individuals with a normal BMI. Tolvaptan efficacy decreases with increasing visceral adiposity.
BACKGROUND: Body mass index (BMI) is an independent predictor of kidney disease progression in individuals with autosomal dominant polycystic kidney disease (ADPKD). Adipocytes do not simply act as a fat reservoir but are active endocrine organs. Authors hypothesized that greater visceral abdominal adiposity would associate with more rapid kidney growth in ADPKD and influence the efficacy of tolvaptan.
DETAILS: 1,053 patients enrolled in the TEMPO 3:4 tolvaptan trial with ADPKD and at high risk of rapid disease progression. In fully adjusted models, the highest tertile of visceral adiposity was associated with greater odds of annual change in TKV of >=7% versus v5% (odds ratio [OR], 4.78 [95% CI, 3.03-7.47]). The association was stronger in women than men (interaction P < 0.01). In linear mixed models with an outcome of percent change in TKV per year, tolvaptan efficacy (% change in TKV) was reduced with higher visceral adiposity (3-way interaction of treatment * time * visceral adiposity, P = 0.002). Visceral adiposity significantly improved classification performance of predicting rapid annual percent change in TKV for individuals with a normal BMI (DeLong's test z score: -2.03; P = 0.04). Greater visceral adiposity was not associated with estimated glomerular filtration rate (eGFR) slope in the overall cohort; however, visceral adiposity was associated with more rapid decline in eGFR slope (below the median) in women (fully adjusted OR, 1.06 [95% CI, 1.01-1.11] per 10 unit increase in visceral adiposity) but not men (OR, 0.98 [95% CI, 0.95-1.02]).
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Copyright © Elsevier Ltd. All rights reserved.
Source: Nowak, K. L., Moretti, F., Bussola, N., et al. (2024). Visceral Adiposity and Progression of ADPKD: A Cohort Study of Patients From the TEMPO 3:4 Trial. Am J Kidney Dis. 2024; 84(3): 275-285. Published: September, 2024. DOI: XXXX.
Effect of Starting Dialysis Versus Continuing Medical Management on Survival and Home Time in Older Adults With Kidney Failure
Older adults starting dialysis when their eGFR fell below 12 mL/min/1.73 mm2 who were not referred for transplant had modest gains in life expectancy and less time at home.
KEY FINDINGS: Older adults starting dialysis when their eGFR fell below 12 mL/min/1.73 mm2 who were not referred for transplant had modest gains in life expectancy and less time at home.
BACKGROUND: Aim of the study is to compare survival and home time between older adults who started dialysis at an estimated glomerular filtration rate (eGFR) less than 12 mL/min/1.73 m2 and those who continued medical management.
DETAILS: Participants were adults aged 65 years or older with chronic kidney failure and eGFR below 12 mL/min/1.73 m2 who were not referred for transplant. Among 20,440 adults (mean age, 77.9 years [SD, 8.8]), the median time to dialysis start was 8.0 days in the group starting dialysis and 3.0 years in the group continuing medical management. Over a 3-year horizon, the group starting dialysis survived 770 days and the group continuing medical management survived 761 days (difference, 9.3 days [95% CI, -17.4 to 30.1 days]). Compared with the group continuing medical management, the group starting dialysis had 13.6 fewer days at home (CI, 7.7 to 20.5 fewer days at home). Compared with the group continuing medical management and forgoing dialysis completely, the group starting dialysis had longer survival by 77.6 days (CI, 62.8 to 91.1 days) and 14.7 fewer days at home (CI, 11.2 to 16.5 fewer days at home).
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Source: Montez-Rath, M. E., Thomas, I., Charu, V., et al. (2024). Effect of Starting Dialysis Versus Continuing Medical Management on Survival and Home Time in Older Adults With Kidney Failure: A Target Trial Emulation Study. Ann Intern Med.. 2024; Epub. Published: August 20, 2024. DOI: 10.7326/M23-302.
MASLD and MASH At the Crossroads of Hepatology Trials and Cardiorenal Metabolic Trials
The challenge is defining the optimal combination of biomarkers, imaging and morbidity/mortality outcomes and ensuring that they are included in future trials while minimizing the burden on patients, trialists and trial sponsors. This paper provides an overview of some of the wide array of CV, liver and kidney measurements that were discussed at the MOSAIC meeting.
KEY FINDINGS: The challenge is defining the optimal combination of biomarkers, imaging and morbidity/mortality outcomes and ensuring that they are included in future trials while minimizing the burden on patients, trialists and trial sponsors. This paper provides an overview of some of the wide array of CV, liver and kidney measurements that were discussed at the MOSAIC meeting.
BACKGROUND: Steatotic liver disease (SLD) is a worldwide public health problem, causing considerable morbidity and mortality. Patients with SLD are at increased risk for major adverse cardiovascular (CV) events, type 2 diabetes mellitus and chronic kidney disease.
DETAILS: Conversely, patients with cardiometabolic conditions have a high prevalence of SLD. In addition to epidemiological evidence linking many of these conditions, there is evidence of shared pathophysiological processes. In December 2022, a unique multi-stakeholder, multi-specialty meeting, called MOSAIC (Metabolic multi Organ Science Accelerating Innovation in Clinical Trials) was convened to foster collaboration across metabolic, hepatology, nephrology and CV disorders. One of the goals of the meeting was to consider approaches to drug development that would speed regulatory approval of treatments for multiple disorders by combining liver and cardiorenal endpoints within a single study. Non-invasive tests, including biomarkers and imaging, are needed in hepatic and cardiorenal trials. They can be used as trial endpoints, to enrich trial populations, to diagnose and risk stratify patients and to assess treatment efficacy and safety. Although they are used in proof of concept and phase 2 trials, they are often not acceptable for regulatory approval of therapies.
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Copyright © John Wiley & Sons, Inc. All rights reserved
Source: Zannad, F., Sanyal, A. J., Butler, J., et al. (2024). MASLD and MASH At the Crossroads of Hepatology Trials and Cardiorenal Metabolic Trials. Journal of Internal Medicine. 2024; 296(1): 24-38. Published: July, 2024. DOI: 10.1111/joim.13793.
Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis
Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.
KEY FINDINGS: Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.
BACKGROUND: Nephritis is a common manifestation of IgA vasculitis and is morphologically indistinguishable from IgA nephropathy. While MEST-C scores are predictive of kidney outcomes in IgA nephropathy, their value in IgA vasculitis nephritis has not been investigated in large multiethnic cohorts.
DETAILS: Biopsies from 262 children and 99 adults with IgA vasculitis nephritis (N=361) from 23 centers in North America, Europe, and Asia were independently scored by three pathologists. MEST-C scores were assessed for correlation with eGFR/proteinuria at biopsy. Because most patients (N=309, 86%) received immunosuppression, risk factors for outcomes were evaluated in this group using latent class mixed models to identify classes of eGFR trajectories over a median follow-up of 2.7 years (interquartile range, 1.2-5.1). Clinical and histologic parameters associated with each class were determined using logistic regression. M, E, T, and C scores were correlated with either eGFR or proteinuria at biopsy. Two classes were identified by latent class mixed model, one with initial improvement in eGFR followed by a late decline (class 1, N=91) and another with stable eGFR (class 2, N=218). Class 1 was associated with a higher risk of an established kidney outcome (time to >= 30% decline in eGFR or kidney failure; hazard ratio, 5.84; 95% confidence interval, 2.37 to 14.4). Among MEST-C scores, only E1 was associated with class 1 by multivariable analysis. Other factors associated with class 1 were age 18 years and younger, male sex, lower eGFR at biopsy, and extrarenal noncutaneous disease. Fibrous crescents without active changes were associated with class 2.
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Source: Barbour, S., Coppo, R., Lee, E., et al. (2024). Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis. Clinical Journal of the American Society of Nephrology . 2024; 19(4): 438-451. Published: May, 2024. DOI: 10.2215/CJN.0000000000000398.
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