Serum Uromodulin Concentrations Research Articles

Serum Uromodulin and All-Cause Mortality in Peritoneal Dialysis Patients: A Chinese Cohort Study

Serum Uromodulin and All-Cause Mortality in Peritoneal Dialysis Patients: A Chinese Cohort Study

Značaj određivanja koncentracije uromodulina u serumu bolesnika sa dijabetes melitusom tip 2

Introduction: In the kidney, cells in the thick ascending limb of the loop of the Henle synthesized uromodulin (UMOD). This study aims to present the evaluation of the uromodulin serum concentration in diabetes mellitus type 2 (T2DM) patients in the early detection of kidney damage. Materials and methods: The study included 50 T2DM patients mean age of 60.75 ± 11.23 years estimated glomerular filtration rate (eGFR) 114.38 ± 22.12 ml/min and a control group of 20 healthy persons. We measured serum concentration of haemoglobin, urea, creatinine, uromodulin (ELISA method), and cystatin C (nephelometry). We determined formulas: Cockcroft-Gault# (combination Cockcroft-Gault for patients with BMI < 30 kg/m2 and Cockcroft-GaultLBW for patients with BMI ≥ 30 kg/m2), CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration equation), and simple Cystatin C. Results: T2DM patients had lower hemoglobin serum concentration as well as eGFR calculated by formulas: Cockcroft-Gault# and CKD-EPI. T2DM patients had significantly higher BMI and cystatin C compared to control group. T2DM patients had significantly lower serum uromodulin concentration (136.51 ± 84.34 vs 220.50 ± 92.39 ng/ml) than in controls. Significant positive correlation between uromodulin and Cockcroft-Gault# (r = 0.432, p = 0.000), CKD-EPI (r = 0.439; p = 0.000) formulas as well as simple cystatin C (r = 0.250, p = 0.02), but negative correlation with age (r = -0.476, p = 0.000), BMI (r = -0.313, p = 0.002) and cystatin C serum concentration (r = -0.293, p = 0.015) were found. Conclusion: The role of serum uromodulin concentration is not still fortified. The results of this study showed that reduced uromodulin serum concentration indicated early kidney damage in T2DM patients.

Individual uromodulin serum concentration is independent of glomerular filtration rate in healthy kidney donors.

The mucoprotein uromodulin is considered to correlate with glomerular filtration rates (GFR) in patients with chronic kidney disease (CKD). Here we investigated how serum uromodulin is associated with measured GFR using inulin-clearance and GFR estimated by CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation in healthy subjects. We assessed possible correlations between uromodulin serum concentrations, inulin-GFR and CKD-EPI-GFR in a well characterized study cohort of 112 healthy living kidney donors with two kidneys before and 64 with one kidney after kidney donation. A subgroup of 32 individuals, which presented data before and after nephrectomy, was assessed separately. All 112 healthy living kidney donors with two kidneys revealed individual serum uromodulin concentrations between 60.1 and 450.5µg/L. Sixty-four healthy kidney donors after nephrectomy had significantly lower median (interquartile range) serum uromodulin concentrations (124 [101-166] vs. 185 [152-238] µg/L), inulin-GFR (67.3 [60.6-74.6] vs. 93.5 [82.1-104.4] mL/min/1.73m2), and CKD-EPI-GFR (61.2 [53.1-69.7] vs. 88.6 [80.0-97.1] mL/min/1.73m2) as compared to the 112 donors before donation (p<0.001). The subgroup of 32 subjects, which presented data before and after nephrectomy, showed almost the same pattern of kidney function. No statistically relevant associations were found between serum uromodulin and inulin-GFR or CKD-EPI-GFR regarding this healthy population. These novel findings indicate that- in contrast to patients with CKD- serum uromodulin concentrations are not correlated with measured and estimated GFR in healthy individuals.

Serum uromodulin is a novel renal function marker in the Japanese population.

Uromodulin, also known as Tamm-Horsfall protein, is the most abundant protein in urine. It has recently been reported that uromodulin exists in a small amount in blood and that its concentration correlates with the estimated glomerular filtration rate (eGFR). First, we generated anti-human uromodulin mouse monoclonal antibodies (mAb(s)) and established a specific enzyme-linked immunosorbent assay (ELISA) for uromodulin. We then performed an observational clinical study to determine if there was a correlation between serum uromodulin concentration and estimates of kidney function and whether the serum uromodulin value could be a biomarker in clinical nephrology. The clinical study included 308 patients with and without chronic kidney disease and healthy volunteers. Serum concentrations of creatinine, cystatin C, and uromodulin were measured and correlations were sought between the eGFR calculated from the creatinine and cystatin C levels and the serum uromodulin concentration. There was a good correlation between the serum uromodulin concentration and the eGFR value calculated from the creatinine (r = 0.76) and cystatin C (r = 0.79) levels. The mean serum uromodulin level in the group with an eGFR > 90mL/min/1.73m2 calculated using cystatin C was significantly higher than that in the group with an eGFR of 80-89mL/min/1.73m2. The serum uromodulin measurement could be a useful biomarker for identification of patients with early deterioration of kidney function.

Association of Serum Uromodulin with Death, Cardiovascular Events, and Kidney Failure in CKD.

Uromodulin is exclusively produced by tubular epithelial cells and released into urine and serum. Higher serum uromodulin has been associated with lower risk for kidney failure in Chinese patients with CKD and with lower risk for mortality in the elderly and in patients undergoing coronary angiography. We hypothesized that lower serum uromodulin is associated with mortality, cardiovascular events, and kidney failure in white patients with CKD. We measured serum uromodulin in 5143 participants enrolled in the German CKD (GCKD) study. The associations of baseline serum uromodulin with all-cause mortality, major adverse cardiovascular events (MACE; a composite of cardiovascular mortality, nonfatal myocardial infarction or stroke, or incident peripheral vascular disease), and kidney failure (dialysis or transplantation) were evaluated using multivariable Cox proportional hazard regression analyses in a cohort study design, adjusting for demographics, eGFR, albuminuria, cardiovascular risk factors, and medication. The mean age of participants was 60±12 years, 60% were male. Mean serum uromodulin concentration was 98±60 ng/ml, eGFR was 49±18 ml/min per 1.73 m2, and 78% had eGFR <60 ml/min per 1.73 m2. Participants in lower serum uromodulin quartiles had lower eGFR and higher albuminuria, prevalence of diabetes, hypertension, coronary artery disease, and more frequent history of stroke at baseline. During a follow-up of 4 years, 335 participants died, 417 developed MACE, and 229 developed kidney failure. In multivariable analysis, the highest serum uromodulin quartile was associated with lower hazard for mortality (hazard ratio [HR], 0.57; 95% CI, 0.38 to 0.87), MACE (HR, 0.63; 95% CI, 0.45 to 0.90), and kidney failure (HR, 0.24; 95% CI, 0.10 to 0.55) compared with the lowest quartile. Higher serum uromodulin is independently associated with lower risk for mortality, cardiovascular events, and kidney failure in white patients with CKD. Deutsches Register für Klinische Studien (DRKS; German national database of clinical studies), DRKS00003971.

Circulating uromodulin inhibits vascular calcification by interfering with pro-inflammatory cytokine signalling.

Uromodulin is produced exclusively in the kidney and secreted into both urine and blood. Serum levels of uromodulin are correlated with kidney function and reduced in chronic kidney disease (CKD) patients, but physiological functions of serum uromodulin are still elusive. This study investigated the role of uromodulin in medial vascular calcification, a key factor associated with cardiovascular events and mortality in CKD patients. Experiments were performed in primary human (HAoSMCs) and mouse (MOVAS) aortic smooth muscle cells, cholecalciferol overload and subtotal nephrectomy mouse models and serum from CKD patients. In three independent cohorts of CKD patients, serum uromodulin concentrations were inversely correlated with serum calcification propensity. Uromodulin supplementation reduced phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of HAoSMCs. In human serum, pro-inflammatory cytokines tumour necrosis factor α (TNFα) and interleukin-1β (IL-1β) co-immunoprecipitated with uromodulin. Uromodulin inhibited TNFα and IL-1β-induced osteo-/chondrogenic signalling and activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated β cells (NF-kB) as well as phosphate-induced NF-kB-dependent transcriptional activity in HAoSMCs. In vivo, adeno-associated virus (AAV)-mediated overexpression of uromodulin ameliorated vascular calcification in mice with cholecalciferol overload. Conversely, cholecalciferol overload-induced vascular calcification was aggravated in uromodulin-deficient mice. In contrast, uromodulin overexpression failed to reduce vascular calcification during renal failure in mice. Carbamylated uromodulin was detected in serum of CKD patients and uromodulin carbamylation inhibited its anti-calcific properties in vitro. Uromodulin counteracts vascular osteo-/chondrogenic transdifferentiation and calcification, at least in part, through interference with cytokine-dependent pro-calcific signalling. In CKD, reduction and carbamylation of uromodulin may contribute to vascular pathology.

Serum uromodulin and progression of kidney disease in patients with chronic kidney disease

BackgroundUromodulin is specifically synthesized and secreted by kidney tubular epithelial cells. Studies on the association of serum uromodulin and outcomes of chronic kidney disease (CKD) are lacking. This study aimed to evaluate whether serum uromodulin was associated with outcomes of patients with CKD.MethodsWe measured serum uromodulin concentrations by ELISA in 2652 CKD patients from the Chinese Cohort Study of Chronic Kidney Disease (C-STRIDE) and investigated the association of serum uromodulin with outcomes of CKD patients, including end-stage kidney disease (ESKD) receiving kidney replacement therapy, cardiovascular events and mortality by Cox proportional hazards regression model.ResultsA total of 2652 CKD patients were enrolled in this study, with an age of 48.7 ± 13.8 years and the baseline eGFR of 49.6 ± 29.4 mL/min/1.73 m2, of whom 58.4% were male. The median level of urinary albumin/creatinine ratio and serum uromodulin was 473.7 mg/g (IQR 134.1–1046.6 mg/g) and 77.2 ng/mL (IQR 48.3–125.9 ng/mL), respectively. Altogether, 404 ESKD, 189 cardiovascular events, and 69 deaths occurred during the median follow-up of 53.6 (IQR 44.0–64.0) months. Lower levels of serum uromodulin were independently associated with higher risk of incident ESKD after adjusting for traditional cardiovascular risk factors, with the hazard ratios (HRs) of 3.23 (95% confidence intervals [CIs] 2.15–4.85) for the middle tertile and 7.47 (95% CI 5.06–11.03) for the bottom tertile, compared with top tertile and 0.31 (95% CI 0.25–0.38) per every standard deviation increase. After further adjustment for the baseline eGFR, the association was greatly attenuated, but still significant, with HRs of 1.92 (95% CI 1.26–2.90) for the bottom tertile compared with top tertile and 0.69 (95% CI 0.55–0.86) per every standard deviation increase.ConclusionsSerum uromodulin is independently associated with an increased risk of incident ESKD in CKD patients.

Serum uromodulin as an early biomarker of tubular atrophy and interstitial fibrosis in patients with glomerulopathies

To assess the significance of the serum uromodulin (Tamm-Horsfall protein - THP) concentration (Sumo) as an early biomarker of tubular atrophy (TA) and interstitial renal fibrosis (IF) in patients with glomerulopathies. 84 patients with glomerulopathy and 11 practically healthy persons (control) were examined. Uromodulin concentrations in serum and urine (Uumo) were measured, renal excretion of this protein and the estimated glomerular filtration rate (eGFR) were established. A semi-quantitative assessment of nephrobioptates was performed. Sumo decreases with a minimum expression of tubular atrophy (TA) or interstitial fibrosis (IF), when the values of eGFR still remain normal. Variations of such excretory parameters of THP as Uumo, daily excretion, and ratio: urinary uromodulin / urinary creatinine, did not manifest a similar trend. Sumo is promising as an early biomarker of fibrotic and atrophic renal damage. The parameters of renal excretion of THP do not seem to have this property. The reason for the delay in the decline of Uumo in the progression of CKD as compared to the decrease in Sumo seems to be the need to maintain a sufficient Uumo to counteract urinary tract infection and stone formation.

The value of uromodulin as a new serum marker to predict decline in renal function.

Uromodulin is the most abundant protein in urine. Low uromodulin has been found associated with diabetes as well as with chronic kidney disease (CKD). Whether it also predicts a future decline in kidney function is not known. We evaluated the association between serum uromodulin and kidney function in 529 patients and performed a genome-wide association study. Clinical parameters including renal function were determined at baseline and reassessed at a 4-year follow-up visit. Patients' serum uromodulin levels were highest associated with a polymorphism in the UMOD coding region and were significantly correlated with estimated glomerular filtration rate (eGFR) (r = 0.242, P < 0.001) and, in an inverse way, with the albumin-creatinine ratio (r = -0.120, P = 0.012). Serum uromodulin concentrations were significantly lower in patients with CKD (eGFR < 60 ml/min per 1.73 m) than in patients with normal kidney function (71.9 ± 29.0 vs. 169.1 ± 76.1 ng/ml, P < 0.001) and the same applied to patients with albuminuria (148.7 ± 72.2 vs. 167.9 ± 77.6 ng/ml, P = 0.008) or hypertension (160.9 ± 74.0 vs. 181.8 ± 87.8 ng/ml, P = 0.037). Prospectively, patients who developed CKD during the follow-up had significantly less uromodulin in serum than those who did not (126.8 ± 42.3 vs. 180.2 ± 79.1 ng/ml, P = 0.003). Serum uromodulin concentration was inversely associated with the development of CKD, even after adjustment for patients age, sex, genotype of the identified polymorphism, hypertension and diabetes status, and eGFR (odds ratio = 0.263, P = 0.019), and it significantly increased the performance of a prediction model for CKD (C-statistics 0.844 vs. 0.804, P = 0.049). The current study is the first evaluating the value of uromodulin in serum as a novel predictive biomarker for renal function and for the incidence of CKD.

Serum Uromodulin Levels in Prediction of Acute Kidney Injury in the Early Phase of Acute Pancreatitis.

In health, uromodulin is the main protein of urine. Serum uromodulin concentrations (sUMOD) have been shown to correlate with kidney function. Acute kidney injury (AKI) is among the main complications of severe acute pancreatitis (AP). No reports exist on sUMOD in patients with AP, including the diagnostic usefulness for early prediction of AP severity. We measured sUMOD during first 72 h of AP. Sixty-six adult patients with AP were recruited at the surgical ward of the District Hospital in Sucha Beskidzka, Poland. AP was diagnosed according to the Revised Atlanta Classification. Blood samples were collected at 24, 48 and 72 h of AP, and sUMOD concentrations were measured with enzyme-linked immunosorbent test. sUMOD decreased non-significantly during the study. Patients with severe AP had non-significantly lower sUMOD concentrations than those with mild disease. Significant positive correlation was observed between sUMOD and estimated glomerular filtration rate on each day of the study and negative correlations were shown between sUMOD and age, serum creatinine, cystatin C and urea. Patients with AKI tended to have lower sUMOD. Although sUMOD correlated significantly with kidney function in the early phase of AP, measuring sUMOD did not allow to reliably predict AP severity or development of AKI.

Serum Uromodulin and Mortality Risk in Patients Undergoing Coronary Angiography.

The mucoprotein uromodulin is the most abundant protein in mammalian urine and has important roles in ion transport, maintenance of water and electrolyte balance, and clearance of bacteria from the urinary tract. Low urinary uromodulin concentrations have been associated with increased mortality risk. However, measuring uromodulin in urine has several preanalytic drawbacks, and sensitive assays for the detection of uromodulin in blood have become available. In this study, we investigated the association of serum uromodulin concentration with cardiovascular biomarkers and mortality risk in a large cohort of patients referred for coronary angiography. Uromodulin concentrations were available in 3057 of 3316 participants of the Ludwigshafen Risk and Cardiovascular Health Study. Higher serum uromodulin concentration associated with a favorable metabolic profile, lower prevalence rates of comorbidities (arterial hypertension, diabetes mellitus, and heart failure), and a lower risk for 10-year mortality, with hazard ratios (95% confidence intervals) of 0.65 (0.54 to 0.78), 0.71 (0.58 to 0.88), and 0.57 (0.45 to 0.73) in the second, third, and fourth quartiles, respectively, compared with the first quartile. The association with reduced mortality was independent of other cardiovascular risk factors, including eGFR, and stronger after adjustment for the genotype of the rs12917707 polymorphism at the UMOD locus. Adding serum uromodulin concentration to established cardiovascular risk prediction scores improved risk prediction. Uromodulin may, therefore, be a useful marker for cardiovascular and renal health.

Serum uromodulin concentrations correlate with glomerular filtration rate in patients with chronic kidney disease.

INTRODUCTION Urinary uromodulin excretion has been associated with kidney diseases. However, serum uromodulin concentrations have not been extensively studied in patients with chronic kidney disease (CKD), and the results of published studies are inconsistent. OBJECTIVES The aims of the study were to evaluate serum uromodulin concentrations in patients with CKD and to assess the utility of serum uromodulin measurements for diagnosing CKD stages. PATIENTS AND METHODS This observational study included 170 patients with CKD stages 1 to 5, not treated by renal replacement therapy, and 30 healthy individuals. The serum levels of creatinine, cystatin C, and uromodulin were measured, and estimated glomerular filtration rate (eGFR) was calculated according to the 2012 CKD Epidemiology Collaboration cystatin‑creatinine equation. RESULTS Among patients with CKD, serum uromodulin concentrations were significantly lower than in controls, and were strongly negatively correlated with renal retention markers (ie, serum creatinine and cystatin C) and strongly positively correlated with eGFR. An inverse, hyperbolic relationship between serum creatinine and uromodulin levels was analogous to the well‑known association between serum creatinine concentrations and eGFR. A receiver‑operating characteristic curve analysis showed a high diagnostic accuracy of the measurement of serum uromodulin concentrations in the assessment of CKD stages. CONCLUSIONS Serum uromodulin concentrations are closely correlated with eGFR, which is the recommended measure of renal function. As uromodulin is produced exclusively by renal tubular cells, the assessment of uromodulin levels in patients with CKD may be an alternative method for evaluating the number of functioning nephrons.

Serum uromodulin predicts graft failure in renal transplant recipients

Objective and methods: Test the ability of serum uromodulin concentrations 1–3 months after renal transplantation to predict all-cause mortality (ACM) and graft loss (GL) in 91 patients.Results: uromodulin predicted GL equivalently to the other markers studied: the risk for GL was reduced by 0.21 per one standard deviation (SD) increase (cystatin C: hazard ratio [HR] 4.57, creatinine: HR 4.53, blood-urea-nitrogen [BUN]: HR 2.50, estimated glomerular filtration rate [eGFR]: HR 0.10). In receiver-operating-characteristic (ROC) analysis, uromodulin predicted GL with an area-under-the curve of 0.782 at an optimal cut-off (OCO) of 24.0 ng/ml with a sensitivity of 90.0% and a specificity of 70.2%.Conclusion: Serum uromodulin predicted GL equivalently compared to conventional biomarkers of glomerular filtration.

A new missense mutation in UMOD gene leads to severely reduced serum uromodulin concentrations — A tool for the diagnosis of uromodulin-associated kidney disease

BackgroundUromodulin-associated Autosomal Dominant Tubulointerstitial Kidney Disease (ADTKD-UMOD) belongs to a group of autosomal dominant inherited diseases caused by mutations in the UMOD gene, which codes for uromodulin, a protein exclusively expressed in renal tubular cells of the ascending limb of the loop of Henle. The diagnosis is hampered by non-specific clinical, laboratory and histological findings. In this study, we evaluated serum uromodulin as diagnostic marker for ADTKD-UMOD in a family with a novel mutation in UMOD. MethodsWe investigated a family with five members suffering from chronic kidney disease of unknown origin (CKD) and three healthy members using whole exome sequencing. Serum uromodulin was measured by ELISA. The uromodulin concentration of each CKD family member was compared to reference CKD groups with similar eGFR and to non-CKD individuals in case of the healthy family members, respectively. ResultsWhole exome sequencing revealed novel missense mutation c.457T>G, p.(Cys153Gly) in UMOD. Serum uromodulin concentration was lower in all affected patients compared to all patients of the reference CKD groups, while healthy family members showed normal values comparable to those of the non-CKD reference group. ConclusionsThe mutation detected in our family leads to severely reduced serum uromodulin concentrations, distinguishing these patients clearly from CKD patients with comparable eGFR. Therefore, serum uromodulin could serve as a simple, new diagnostic marker to identify patients with ADTKD-UMOD.

Evidence for a role of uromodulin in chronic kidney disease progression

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. 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. 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. 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.