Background: Uromodulin (also known as Tamm-Horsfall protein) is the most abundant urinary protein in healthy individuals and exhibits diverse functions including prevention of ascending urinary tract infections by binding type I-fimbriated Escherichia coli. Although uromodulin is targeted to the apical membrane of thick ascending limb (TAL) cells and secreted into the lumen, detectable levels are also found in venous blood. Uromodulin has been shown to interact with and activate specific components of the immune system, and thus, may act as a signalling molecule for renal tubular damage.
Methods: In order to investigate the potential involvement of uromodulin in chronic kidney disease (CKD), we quantified uromodulin in paired urine and serum from 14 healthy volunteers and 77 CKD patients. Clinical parameters such as estimated GFR (eGFR), proteinuria and urinary N-acetyl-beta-D-glucosaminidase (NAG) were measured. Mean infiltration and atrophy score were assessed in patient biopsies. Additionally, tumour necrosis factor-alpha, interleukin-6 (IL-6), IL-8 and IL-1 beta were measured in serum samples.
Results: eGFR correlated positively with urinary uromodulin and negatively with serum uromodulin. Patients with abnormally low urinary uromodulin showed a broader range of serum uromodulin. Patients with both very low urinary and serum uromodulin had the highest tubular atrophy scores. There was a positive correlation of serum uromodulin with all cytokines measured. Additionally, in in vitro experiments, uromodulin caused a dose-dependent increase in pro-inflammatory cytokine release from whole blood.
Conclusions: Our data suggest that TAL damage, or damage distal to the TAL, results in an elevated interstitial uromodulin, which stimulates an inflammatory response. Persistent chronic TAL damage reduces TAL cell numbers and attenuates urinary and serum uromodulin concentrations. The combined analysis of serum and urinary uromodulin provides new insights into the role of uromodulin in CKD and suggest that uromodulin may be an active player in CKD progression.
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http://dx.doi.org/10.1093/ndt/gfp748 | DOI Listing |
Am J Kidney Dis
January 2025
Yale Department of Chronic Disease Epidemiology and Center for Perinatal, Pediatric and Environmental Epidemiology, Yale School of Public Health, New Haven, CT, USA; Mid-Norway Center for Sepsis Research, Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
Rationale & Objective: Observational studies suggest that uromodulin, produced by the kidneys, is associated with a reduced the risk of upper urinary tract infections, but inferences are limited by potential confounding factors. This study sought to explore further the validity of this association using Mendelian randomization.
Study Design: Two-sample Mendelian randomization study.
Pediatr Nephrol
January 2025
Department of Paediatrics, University Medical Centre Maribor, Ljubljanska ulica 5, 2000, Maribor, Slovenia.
Background: Serum and urinary uromodulin are emerging as potential cardiovascular risk factors. The aim of our study was to determine uromodulin in both serum and urine to evaluate their potential as early cardiovascular risk markers and markers of kidney function in children and young adults.
Methods: This case-control study included 72 participants - 42 children and young adults with chronic kidney disease stages 1-2 and 30 healthy controls.
Ren Fail
December 2025
Department of Nephrology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
Objective: The innate immune defense plays a pivotal role in protecting the urinary tract from uropathogenic invasion and maintaining immune homeostasis. Dysregulation of the innate immune system can result in recurrent urinary tract infections (RUTI) due to heightened susceptibility to uropathogens. Despite this, predicting the risk of recurrence and the degree of immune compromise in patients who have had one urinary tract infection remains challenging.
View Article and Find Full Text PDFKidney Int Rep
December 2024
Institute of Physiology, University of Zurich, Zurich, Switzerland.
Presse Med
December 2024
Division of Pathology, Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, Canada.
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