Urinary Fetuin-A Research Articles

Associations of urinary fetuin-A with histopathology and kidney events in biopsy-proven kidney disease.

Fetuin-A is implicated in the pathogenesis of vascular calcification in chronic kidney disease (CKD); however, the relationship between fetuin-A, histopathologic lesions and long-term kidney outcomes in patients with various types of kidney disease remains unclear. We measured urinary fetuin-A levels in 335 individuals undergoing clinically indicated native kidney biopsy. The expressions of fetuin-A mRNA and protein in the kidney were assessed using RNA sequencing and immunohistochemistry. The association of urinary fetuin-A with histopathologic lesions and major adverse kidney events (MAKE), defined as a decline in estimated glomerular filtration rate (eGFR) of at least 40%, kidney failure or death, was analyzed. Urinary fetuin-A levels showed a positive correlation with albuminuria (rs=0.67, P<.001) and a negative correlation with eGFR (rs=-0.46, P<.001). After multivariate adjustment, higher urinary fetuin-A levels were associated with glomerular inflammation, mesangial expansion, interstitial fibrosis and tubular atrophy, and arteriolar sclerosis. Using a 1 transcript per million gene expression cutoff, we found kidney fetuin-A mRNA levels below the threshold in both individuals with normal kidney function and those with CKD. Additionally, immunohistochemistry revealed reduced fetuin-A staining in tubular cells of CKD patients compared with normal controls. During a median 21-month follow-up, 115 patients experienced MAKE, and Cox regression analysis confirmed a significant association between elevated urinary fetuin-A and MAKE. This association remained significant after adjusting for potential confounding factors. Urinary fetuin-A is associated with chronic histological damage and adverse clinical outcomes across a spectrum of biopsy-proven kidney diseases.

Urinary Post-Translationally Modified Fetuin-A Protein Is Associated with Increased Risk of Graft Failure in Kidney Transplant Recipients.

Urinary fetuin-A has been identified as a biomarker for acute kidney injury and is proposed as a biomarker for early detection of kidney function decline. We investigated whether fetuin-A could serve as a marker of graft failure in kidney transplant recipients (KTRs). Data of KTR with a functioning graft ≥1 year that were enrolled in the TransplantLines Food and Nutrition Biobank and cohort study were used. Graft failure was defined as the need for re-transplantation or (re-)initiation of dialysis. Urinary fetuin-A was measured using an enzyme-linked immunosorbent assay kit that detected post-translationally modified fetuin-A in the urine (uPTM-FetA). In the main analyses, 24h uPTM-FetA excretion was used. In the sensitivity analyses, we excluded the outliers in 24h uPTM-FetA excretion, and we used uPTM-FetA concentration and uPTM-FetA concentration indexed for creatinine instead of 24h uPTM-FetA excretion. A total of 627 KTRs (age 53 ± 13 years, 42% females) were included at 5.3 (1.9-12.2) years after transplantation. The estimated glomerular filtration rate (eGFR) was 52 ± 20 mL/min/1.73 m2 and uPTM-FetA excretion was 34 (17-74) µg/24 h. During a median follow-up of 5.3 (4.5-6.0) years after baseline measurements, 73 (12%) KTRs developed graft failure. The association of 24h uPTM-FetA excretion with increased risk of graft failure was not constant over time, with increased risk only observed after 3 years from baseline measurements, independent of potential confounders including kidney function and 24 h urinary protein excretion (hazard ratio per doubling of 24h uPTM-FetA excretion = 1.31; 95% confidence interval = 1.06-1.61). This finding was robust in the sensitivity analyses. Our findings suggest that uPTM-FetA can be used as a marker for early detection of graft failure in KTR. Further studies are needed to confirm our findings.

Urinary Fetuin-A Fragments Predict Progressive Estimated Glomerular Filtration Rate Decline in Two Independent Type 2 Diabetes Cohorts of Different Ethnicities

Introduction: There is a great clinical need for novel markers to predict kidney function decline in patients with type 2 diabetes. We explored the potential of posttranslationally modified fetuin-A fragments in urine (uPTM-FetA) as such a marker. Methods: We included patients with type 2 diabetes from two independent, nonoverlapping prospective cohort studies. A cut-off for uPTM-FetA, measured via ELISA method, was determined using the Youden index in the primary cohort of patients with type 2 diabetes from Taiwan. Kidney endpoint was defined as an estimated glomerular filtration rate (eGFR) decline ≥30% from baseline, reaching of an eGFR <15 mL/min/1.73 m², or a need of renal replacement therapy. Prospective associations were assessed in Cox regression models. All analyses were replicated in a cohort of patients with type 2 diabetes from the Netherlands. Results: In total, 294 patients with type 2 diabetes (age 61 ± 10 years, 55% male, eGFR 88 ± 16 mL/min/1.73 m²) were included in the primary cohort. During a follow-up of median 4.6 years, 42 participants (14%) experienced the kidney endpoint. Using the defined cut-off, a high uPTM-FetA was associated with a higher risk of renal function decline (P_log-rank < 0.0001). This association was similar in subgroups depending on albuminuria. This association remained, independent of age, sex, baseline eGFR, albuminuria, HbA1c, and other potential confounders (HR: 9.94; 95% CI: 2.96–33.40; p < 0.001 in the final model). Analyses in the validation cohort (376 patients with type 2 diabetes, age 64 ± 11 years, 66% male, eGFR 76 ± 24 mL/min/1.73 m²) using the same cut-off yielded similar results. Conclusion: uPTM-FetA was independently associated with kidney function decline in patients with type 2 diabetes validated in a 2-cohort study. The significant additive predictive power of this biomarker from conventional risk factors suggests its clinical use for renal function progression in patients with type 2 diabetes.

Urinary fetuin-A peptides as a new marker for impaired kidney function in patients with type 2 diabetes.

BackgroundThe hepatokine fetuin-A, released by the human liver, promotes pro-inflammatory effects of perivascular fat. The involvement of inflammation in type 2 diabetes mellitus (T2DM) can affect the kidney and contribute to the development of diabetic kidney disease. Therefore we examined the association of urinary fetuin-A protein fragments with renal damage in T2DM patients.MethodsUrinary peptides of 1491 individuals using proteome data available from the human urine proteome database were analysed. Prediction of proteases involved in urinary peptide generation was performed using the Proteasix tool.ResultsWe identified 14 different urinary protein fragments that belong to the region of the connecting peptide (amino acid 301–339) of the total fetuin-A protein. Calpains (CAPN1 and CAPN2), matrix metalloproteinase and pepsin A-3 were identified as potential proteases that were partially confirmed by previous in vitro studies. Combined fetuin-A peptides (mean of amplitudes) were significantly increased in T2DM patients with kidney disease and to a lesser extent with cardiovascular risk. Furthermore, fetuin-A peptide levels displayed a significant negative correlation with baseline estimated glomerular filtration rate (eGFR) values (r = −0.316, P < 0.0001) and with the slope (%) of eGFR per year (r = −0.096, P = 0.023). A multiple regression model including fetuin-A peptide and albuminuria resulted in a significantly improved correlation with eGFR (r = −0.354, P < 0.0001) compared with albuminuria, indicating an added value of this novel biomarker.ConclusionsThe urinary proteome analysis demonstrated the association of fetuin-A peptides with impaired kidney function in T2DM patients. Furthermore, fetuin-A peptides displayed early signs of kidney damage before albuminuria appeared and therefore can be used as markers for kidney disease detection.

Urinary fetuin-A as a possible biomarker for pregnancy diagnosis in Murrah buffaloes

Urinary fetuin-A as a possible biomarker for pregnancy diagnosis in Murrah buffaloes

Quantitative Urinary Proteome Reveals Potential Biomarkers for Ureteropelvic Junction Obstruction.

Ureteropelvic junction obstruction (UPJO) is a common obstructive disease. To investigate useful urinary biomarkers in UPJO children, the urinary proteome in UPJO infants is analyzed and it is compared with normal controls. A tandem mass tag (TMT)-based quantitative proteomics study is performed to analyze the proteome of bladder urine (BU) and pelvis urine (PU) from unilateral UPJO infants with differential renal function less than 40% and they are compared with normal control urine (CON). GO analysis is then utilized to analyze general characterization of the proteins. Proteomic results are verified by western blot. There are 81 and 186 proteins significantly changed in BU and PU groups, respectively, as compared to the CON group. Fifty proteins overlaps are found between these two sets of statistically significant differential proteins. These 50 common differential proteins are involved in multiple biological processes. The increased urinary abundance of Fetuin-A, AGP1, AGP2, Alpha-1-microglobulin/Bikunin Precursor (AMBP), and prostaglandin-H2D-isomerase (PGDS) are verified by western blot analysis. This proteomic analysis indicates that urinary Fetuin-A, AGP1, AGP2, protein AMBP, and PGDS may serve as noninvasive potential biomarkers and these proteins can help to further yield pathological mechanisms involved in UPJO.

Urine and serum fetuin-A levels in patients with urolithiasis.

Introduction:Fetuin-A is a glycoprotein secreted by liver and has been shown to inhibit extraosseous mineralization. Urolithiasis may be a manifestation in the urinary tract due to fetuin deficiency in urine. The objective of this study was to compare the 24-h urine and serum fetuin-A levels of patients with and without urolithiasis.Methods:Serum and 24-h urine fetuin-A levels were measured in 41 patients with bilateral, multiple, or recurrent urinary tract calculi (Group A) and 41 matched controls with no calculi (Group B). Fetuin levels were measured by enzyme linked immunosorbent assay. Serum and urine fetuin-A levels in the two groups were compared.Results:The median (range) 24-h urine fetuin-A value in Group A was 11.9 (1.12–221) mg/day and in Group B was 37.7 (1.28–125) mg/day. This difference was statistically significant (Mann–Whitney test, P = 0.0169). The median (range) serum fetuin-A in Group A was 0.67 (0.05–2.68) g/L and in Group B was 0.99 (0.01–5.5) g/L. The difference between serum values in the two arms was not statistically significant (Mann–Whitney test, P = 0.1817). However, the serum creatinine-adjusted mean log serum fetuin and urine fetuin were significantly different in the two arms (P = 0.003). The mean ± standard deviation (range) serum creatinine in Group A was 0.98 ± 0.25 (0.56–1.58) mg% and in Group B was 0.83 ± 0.16 (0.58–1.18) mg% (two sample t-test, P = 0.0031).Conclusions:Patients with urolithiasis have lower urine fetuin-A and creatinine-adjusted serum fetuin-A levels.

The relationship between serum and urinary Fetuin-A levels and kidney stone formation among kidney stone patients.

IntroductionMineralization inhibitors are required to prevent the precipitation of minerals and inhibit the formation of kidney stones and other ectopic calcifications. In laboratory studies, Fetuin-A as a glycoprotein has inhibited hydroxyapatite precipitation in calcium and phosphate supersaturated solutions; however, information about patients with kidney stones is limited. The aim of this study was to investigate the association of serum and urinary Fetuin-A levels with calcium oxalate kidney stones.Material and methodsIn this case-control study, 30 patients with kidney stones and 30 healthy individuals without any history of urolithiasis who were referred to the urology ward of Sina Hospital of Tehran, Iran, in 2015 were entered into the study. All patients underwent computerized tomography scans. After collecting demographic information, serum and urine levels of Fetuin-A and some other calcification inhibitors and promoters, were measured and compared using T-test, Mann-Whitney and logistic regression between the two study groups.ResultsPatients with kidney stones, on average, had lower levels of Serum Fetuin-A (1522.27 ±755.39 vs. 1914.64 ±733.76 μg/ml; P = 0.046) as well as lower levels of Urine Fetuin-A (944.62 ±188.5 vs. 1409.68 ±295.26 μg/ml; P <0.001). Multivariate logistic analysis showed that urinary calcium and serum creatinine are the risk factors and Fetuin-A is a urinary protective factor for kidney stones.ConclusionsPFC Our study showed that patients with kidney stones had lower serum and urinary levels of Fetuin-A. In the logistic regression model, urinary Fetuin-A was reported as a protective factor for kidney stones.

The Relationship between Serum and Urinary Fetuin-A Levels and Kidney Stones Formation Among kidney stone patients

The Relationship between Serum and Urinary Fetuin-A Levels and Kidney Stones Formation Among kidney stone patients

Evaluation of serum and urine fetuin-A levels in children with acute lymphoblastic leukemia during and after high-dose methotrexate therapy: Relation to toxicity

Background/objectives: Fetuin-A is a multifunctional protein with its urine level was considered as a marker of acute kidney injury. We investigated the serum and urine fetuin-A in acute lymphoblastic leukemia (ALL) children during and after high-dose methotrexate (HDMTX).Methods: Twenty-two ALL children and 20 matched healthy controls were included. Liver transaminases, serum creatinine, estimated glomular filtration rate (eGFR), creatinine clearance (CrCl), serum β2 microglobulin (B2M), and serum and urine fetuin-A levels were assayed pre and 4 months after the consolidation. Among a subgroup of 15 patients, the investigations were performed 42 hours after the start of the second and the fourth HDMTX infusions.Results: HDMTX was well tolerated. During HDMTX, there was significant decline in serum fetuin-A together with significant rise of urine fetuin-A and B2M levels compared to the control and to the pre-consolidation levels, changes that persisted 4 months after the consolidation despite recovery of the significantly altered renal functions. The second HDMTX-related serum fetuin-A level directly correlated with eGFR and CrCl (r = 0.86, P < 0.0001 and r = 0.67, P = 0.016, respectively). Four months after consolidation, urine fetuin-A directly correlated with serum creatinine (r = 0.54, P = 0.004) and inversely correlated with the eGFR (r = −0.66, P < 0.0001).Conclusion: Significant disturbance in serum and urinary fetuin-A levels, which was related to renal functions, had occurred during HDMTX and persisted for at least 4 months after the consolidation. Serum and urine fetuin-A could be sensitive markers for subtle renal dysfunction in ALL children.

Urine Fetuin-A is a biomarker of autosomal dominant polycystic kidney disease progression.

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by numerous fluid-filled cysts that frequently result in end-stage renal disease. While promising treatment options are in advanced clinical development, early diagnosis and follow-up remain a major challenge. We therefore evaluated the diagnostic value of Fetuin-A as a new biomarker of ADPKD in human urine.ResultsWe found that renal Fetuin-A levels are upregulated in both Pkd1 and Bicc1 mouse models of ADPKD. Measurement by ELISA revealed that urinary Fetuin-A levels were significantly higher in 66 ADPKD patients (17.5 ± 12.5 μg/mmol creatinine) compared to 17 healthy volunteers (8.5 ± 3.8 μg/mmol creatinine) or 50 control patients with renal diseases of other causes (6.2 ± 2.9 μg/mmol creatinine). Receiver operating characteristics (ROC) analysis of urinary Fetuin-A levels for ADPKD rendered an optimum cut-off value of 12.2 μg/mmol creatinine, corresponding to 94% of sensitivity and 60% of specificity (area under the curve 0.74 ; p = 0.0019). Furthermore, urinary Fetuin-A levels in ADPKD patients correlated with the degree of renal insufficiency and showed a significant increase in patients with preserved renal function followed for two years.ConclusionsOur findings establish urinary Fetuin-A as a sensitive biomarker of the progression of ADPKD. Further studies are required to examine the pathogenic mechanisms of elevated renal and urinary Fetuin-A in ADPKD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0463-7) contains supplementary material, which is available to authorized users.

Urinary Fetuin-A Is a Novel Marker for Diabetic Nephropathy in Type 2 Diabetes Identified by Lectin Microarray

We analyzed the urine samples of patients with type 2 diabetes at various stages of diabetic nephropathy by lectin microarray to identify a biomarker to predict the progression of diabetic nephropathy. Japanese patients with type 2 diabetes at various stages of nephropathy were enrolled and we performed lectin microarray analyses (n = 17) and measured urinary excretion of fetuin-A (n = 85). The increased signals of urine samples were observed in Siaα2-6Gal/GalNAc-binding lectins (SNA, SSA, TJA-I) during the progression of diabetic nephropathy. We next isolated sialylated glycoproteins by using SSA-lectin affinity chromatography and identified fetuin-A by liquid chromatography–tandem mass spectrometer. Urinary excretion of fetuin-A significantly increased during the progression of albuminuria (A1, 0.40±0.43; A2, 0.60±0.53; A3 1.57±1.13 ng/gCr; p = 7.29×10−8) and of GFR stages (G1, 0.39±0.39; G2, 0.49±0.45; G3, 1.25±1.18; G4, 1.34±0.80 ng/gCr; p = 3.89×10−4). Multivariate logistic regression analysis was employed to assess fetuin-A as a risk for diabetic nephropathy with microalbuminuria or GFR<60 mL/min. Fetuin-A is demonstrated as a risk factor for both microalbuminuria and reduction of GFR in diabetic nephropathy with the odds ratio of 4.721 (1.881–11.844) and 3.739 (1.785–7.841), respectively. Collectively, the glycan profiling analysis is useful method to identify the urine biomarkers and fetuin-A is a candidate to predict the progression of diabetic nephropathy.

Reduced Serum Fetuin-A in Nephrotic Children: A Consequence of Proteinuria?

Background: The extracellular protein fetuin-A is a potent soluble inhibitor of calcification, and its deficiency has been associated with vascular calcification in dialysis patients. In proteinuric patients, significant urinary losses of fetuin-A may cause low serum fetuin-A levels. Methods: In a cross-sectional study, urinary/serum concentrations of fetuin-A were investigated in proteinuric children with glomerular diseases and preserved renal function (n = 58) in comparison to healthy controls (n = 246). Results: Mean fetuin-A serum concentrations were clearly reduced in children with nephrotic syndrome (0.25 ± 0.14 g/l, p < 0.001), slightly reduced in children with large proteinuria (0.39 ± 0.15 g/l, p < 0.05), and comparable to controls in those with mild proteinuria (0.45 ± 0.14 vs. 0.46 ± 0.12 g/l). Fetuin-A was positively correlated with serum protein (r = 0.58), albumin (r = 0.57), and calcium (r = 0.64), but negatively correlated with proteinuria (r = –0.41), albuminuria (r = –0.46), and urinary fetuin-A excretion (r = –0.48; each p < 0.001). The fractional excretion of fetuin-A was significantly associated with the degree of proteinuria and serum fetuin-A levels. However, the urinary loss of fetuin-A and albumin in nephrotic children differed by three orders of magnitude and the mean fractional excretion of fetuin-A was only 1/10 of that of albumin (0.016 ± 0.029 vs. 0.162 ± 0.403%; p < 0.001). Conclusions: Fetuin-A is clearly reduced in children with nephrotic syndrome and associated with the degree of hypoalbuminemia. This is due to urinary fetuin-A loss and/or reduced hepatic synthesis. Persistent fetuin-A deficiency may have an impact on cardiovascular morbidity in nephrotic children.

The Role of Alpha2-Heremans Schmid Glycoprotein (Fetuin-A) in the Etiology of Urolithiasis

Aim: To determine the role of fetuin-A, a glycoprotein which represents the alpha-2 band of protein electrophoresis and which prevents the precipitation of calcium both in the intravascular and extravascular areas, in the etiology of urolithiasis. Material and Method: Sixty-nine patients (55 patients with urolithiasis and 14 patients with a history of urolithiasis) and 44 control subjects (patients without urolithiasis) were included in the study. Fetuin-A concentrations were measured by the enzyme-linked immunosorbent assay method both in the serum and in 24-hour urine samples obtained from the patients and the control group. In addition, the other activators and inhibitors that may play a role in urolithiasis were measured biochemically. Results: There were no statistically significant differences in serum sodium, potassium, creatinine, calcium, magnesium, phosphorus, uric acid, albumin, and parathyroid hormone levels between the patients and the control group. Daily urine volume, magnesium, uric acid, potassium, sodium, calcium, phosphorus, citrate, oxalate and cystine levels measured in 24-hour urine collections were similar in both the patients and the control groups. The serum fetuin-A level was 0.5 g/l in the patients with urolithiasis, 0.45 g/l in the patients with a history of urolithiasis, and 0.51 g/l in the control group (p > 0.05). The urine fetuin-A levels were 8.71, 5.7 and 10.81 mg/d, respectively (p > 0.05). The data were not statistically significant between the 3 groups. Conclusion: There was no difference in between the serum and urine fetuin-A levels between the groups with and without urolithiasis. This result does not correlate with the results of another study which suggested a role for fetuin-A in the etiology of urolithiasis. This discrepancy needs to be elucidated with a larger population in further studies.

Urine fetuin‐A values in relation to the presence of urolithiasis

To investigate the relationship of urine fetuin-A and other promotors and inhibitors of urine crystalization with urolithiasis, as fetuin-A inhibits the precipitation of hydroxyapatite from supersaturated solutions of calcium and phosphate in vitro but no information on urine fetuin-A in patients with urolithiasis is available. In all, 39 patients with urolithiasis and 22 individuals with no urolithiasis or probands with undetected stones were involved. All patients underwent kidney ultrasonography and X-ray examination, and body mass index (BMI) was calculated. Serum creatinine, parathyroid hormone, calcium, magnesium, anorganic phosphate, uric acid and urine creatinine, albumin, alpha(1)-microglobulin, sulphate, oxalate, citrate and fetuin-A (ELISA) were determined. The patients with urolithiasis had lower urine fetuin-A levels (median 4.9 vs 0.77 mg/day; P < 0.01) and citraturia levels (1.7 vs 5.1 mmol/day; P = 0.02); and higher calciuria (6.5 vs 5.2 mmol/day) and oxaluria (0.47 vs 0.25; P = 0.04). Patients with fetuin-A levels in the lowest quartile had an odds ratio of 36 compared with individuals in the highest quartile. The sensitivity of the urine fetuin-A level for urolithiasis was 97.4% and specificity was 100% (area under the curve 0.99; 95% confidence interval 0.94-1.0) using a urine fetuin-A threshold of <or=2.1 mg/day. Values of urine fetuin-A did not correlate with gender, age or BMI. Our study indicates, for the first time, that patients with documented urolithiasis had lower fetuin-A concentrations independent of other conventional promotors and inhibitors of urine crystallization.

Exosomal Fetuin-A identified by proteomics: A novel urinary biomarker for detecting acute kidney injury

Urinary exosomes containing apical membrane and intracellular fluid are normally secreted into the urine from all nephron segments, and may carry protein markers of renal dysfunction and structural injury. We aimed to discover biomarkers in urinary exosomes to detect acute kidney injury (AKI), which has a high mortality and morbidity. Animals were injected with cisplatin. Urinary exosomes were isolated by differential centrifugation. Protein changes were evaluated by two-dimensional difference in gel electrophoresis and changed proteins were identified by mass spectrometry. The identified candidate biomarkers were validated by Western blotting in individual urine samples from rats subjected to cisplatin injection; bilateral ischemia and reperfusion (I/R); volume depletion; and intensive care unit (ICU) patients with and without AKI. We identified 18 proteins that were increased and nine proteins that were decreased 8 h after cisplatin injection. Most of the candidates could not be validated by Western blotting. However, exosomal Fetuin-A increased 52.5-fold at day 2 (1 day before serum creatinine increase and tubule damage) and remained elevated 51.5-fold at day 5 (peak renal injury) after cisplatin injection. By immunoelectron microscopy and elution studies, Fetuin-A was located inside urinary exosomes. Urinary Fetuin-A was increased 31.6-fold in the early phase (2-8 h) of I/R, but not in prerenal azotemia. Urinary exosomal Fetuin-A also increased in three ICU patients with AKI compared to the patients without AKI. We conclude that (1) proteomic analysis of urinary exosomes can provide biomarker candidates for the diagnosis of AKI and (2) urinary Fetuin-A might be a predictive biomarker of structural renal injury.