Relationship Between Serum Uromodulin as a Marker of Kidney Damage and Metabolic Status in Patients with Chronic Kidney Disease of Non-Diabetic Etiology.

Chronic kidney disease (CKD) is often associated with dyslipidemia, marked by lipid abnormalities that can worsen kidney function and increase cardiovascular risk. A promising biomarker for evaluating kidney function and metabolic status in chronic kidney disease (CKD) is serum uromodulin (sUmod). This study sought to further investigate the relationship between sUmod levels and metabolic status in non-diabetic CKD patients. A sensitive ELISA method was used to determine sUmod levels in 90 adults with obstructive nephropathy and 30 healthy controls. Kidney function was assessed using the measured glomerular filtration rate (mGFR) through renal clearance of 99mTc-diethylenetriamine penta-acetic acid, along with cystatin C levels. Additionally, glycemic and lipid statuses were evaluated. sUmod concentrations showed a significant association with High-density lipoprotein (HDL) levels. Furthermore, CKD patients with lower sUmod levels had significantly lower Apolipoprotein A-I (Apo A-I) values compared to the control group. Significant predictors of lower sUmod concentrations identified in this study were higher glycemia (B = -15.939; p = 0.003) and lower HDL cholesterol levels (B = 20.588; p = 0.019). We conclude that, in addition to being significantly reduced in CKD patients, sUmod is a potential predictor of metabolic syndrome (MS) in this population. Lower sUmod concentrations, independent of mGFR, predict lower HDL cholesterol levels and higher glycemia values.

Neutrophil extracellular traps protect the kidney from ascending infection and are required for a positive leukocyte dipstick test.

Lower urinary tract infection (UTI) is common but only rarely complicated by pyelonephritis. However, the mechanisms preventing extension to the kidney are unclear. Here, we identified neutrophil extracellular traps (NETs) in healthy human urine that provide an antibacterial defense strategy within the urinary tract. In both in vivo murine models of UTI where uropathogenic E. coli are inoculated into the bladder and ex vivo human urine models, NETs interacted with uromodulin to form large webs that entrapped the bacteria. Peptidyl arginine deiminase 4 (PADI4) inhibition in mice blocked NETosis and resulted in progression of cystitis into pyelonephritis, suggesting that NETosis of urinary neutrophils acts to prevent bacterial ascent into the kidney. Analysis of UK Biobank data revealed that genetic variants in PADI4 that associated with increased risk of rheumatoid arthritis in multiple genome-wide association studies were consistently associated with reduced susceptibility to UTI. Last, we showed that urine dipstick testing for leukocyte esterase was negative in the presence of intact blood neutrophils but became positive when neutrophils were stimulated to NET, and this could be prevented by selective PADI4 inhibition, demonstrating that this test does not detect absolute neutrophil count, as has long been assumed, but specifically detects neutrophils that have undergone NETosis. These findings highlight the role of NETosis in preventing ascending infections in the urinary tract and improve our understanding of one of the most common clinical tests in medicine.

Association of major candidate protein biomarkers and long-term diabetic kidney disease progression among Asians with young-onset type 2 diabetes mellitus.

AIMS: We aim to determine the association of seven major candidate protein biomarkers and diabetic kidney disease (DKD) progression among Asians with young-onset type 2 diabetes mellitus (T2DM). METHODS: 824 T2DM patients (onset ≤ 40 years old) were classified as DKD progressors based on yearly estimated glomerular filtration rate (eGFR) decline of >3 ml/min/1.73 m2 or >40 % from baseline. Plasma leucine-rich α-2-glycoprotein 1 (pLRG1), tumor necrosis factor-receptor 1 (pTNF-R1), pigment epithelium-derived factor (pPEDF), urinary α-1-microglobulin (uA1M), kidney injury molecular 1 (uKIM-1), haptoglobin (uHP) and uromodulin (uUMOD) were measured using enzyme-linked immunoassays. RESULTS: Over 5.7 years of follow-up, 25.2 % of patients were DKD progressors. Elevated levels of pLRG1, pTNF-R1, pPEDF, uA1M, uKIM-1 and uHP were associated with DKD progression. The association between pTNF-R1 levels and DKD progression persisted after adjusting for clinical covariates (OR 1.84, 95 %CI 1.44-2.34, p < 0.001). The effects of pTNF-R1 were partially mediated through hyperglycemia (8 %) and albuminuria (10 %). Inclusion of pTNF-R1 in a clinical variable-based model improved the area under the receiver operating characteristics curve for predicting DKD progression by 0.02, from 0.72 (95 %CI 0.68-0.76) to 0.74 (95 %CI 0.70-0.78), p = 0.099. CONCLUSIONS: Among seven major candidate proteins, pTNF-R1, partially mediated through hyperglycemia and albuminuria, robustly predicted DKD progression among Asians with young-onset T2DM.

Emerging multisystem biomarkers in hereditary transthyretin amyloidosis: a pilot study.

Hereditary transthyretin (ATTRv) amyloidosis is a rare, adult-onset, progressive, multisystemic condition caused by TTR pathogenic variants. Reliable biomarkers are needed to allow early diagnosis and to monitor disease severity and progression. We measured serum concentrations of growth differentiation factor-15 (GDF-15) and uromodulin (Umod) in ATTRv patients to evaluate correlations with standard markers of disease severity (FAP stage and PND score). Blood samples were collected from 16 patients diagnosed with ATTRv amyloidosis and a verified TTR variant and from 26 healthy controls. ATTRv patients were stratified by clinical phenotype (neurologic vs. mixed), genotype (V30M vs. non-V30M), and disease severity. We found significantly higher levels of serum GDF-15 in ATTRv patients compared with controls. Mean serum Umod levels were significantly lower in patients with ATTRv than controls. A positive correlation was found between serum Umod and estimated glomerular filtration rate (eGFR), while an inverse correlation was found with cystatin C levels. Conversely, GDF-15 showed a negative correlation with eGFR, and a direct correlation with cystatin C levels. No correlation was demonstrated between GDF-15 or Umod levels and traditional cardiac biomarkers. The results identify alteration of serum levels of GDF-15 and Umod in ATTRv amyloidosis.

Identification of uromodulin deposition in the stroma of perinephric fibromyxoid nephrogenic adenoma by mass spectrometry.

Nephrogenic adenoma (NA) is an epithelial lesion that usually occurs in the mucosa of the urinary tract. Rare cases of deep infiltrative or perinephric lesions have also been reported. Recently, NA with characteristic fibromyxoid stroma (fibromyxoid NA) has been proposed as a distinct variant. Although shedding of distal renal tubular cells due to urinary tract rupture has been postulated as the cause of NA in general, the mechanism underlying extraurinary presentation of NA and fibromyxoid stromal change in fibromyxoid NA remains unknown. In this study, we performed mass spectrometry (MS) analysis in a case of perinephric fibromyxoid NA of an 82-year-old man who underwent right nephroureterectomy for distal ureteral cancer. The patient had no prior history of urinary tract injury or radiation. Periodic acid-Schiff staining-positive eosinophilic structureless deposits in the stroma of fibromyxoid NA were microdissected and subjected to liquid chromatography/MS. The analysis revealed the presence of a substantial amount of uromodulin (Tamm-Horsfall protein). The presence of urinary content in the stroma of perinephric fibromyxoid NA suggests that urinary tract rupture and engraftment of renal tubular epithelial cells directly cause the lesion.

Vesicoureteral Reflux Causes Interstitial Inflammation in Pediatric Kidney Allograft: A Clinicopathological Analysis of 1-Year Protocol Biopsies.

INTRODUCTION: At present, there is limited evidence of the histological impact of vesicoureteral reflux (VUR) on pediatric kidney allografts. In this study, we aimed to investigate the relationship between VUR diagnosed by voiding cystourethrography (VCUG) and 1-year protocol biopsy results. METHODS: One hundred thirty-eight pediatric kidney transplantations were performed in Toho University Omori Medical Center between 2009 and 2019. We included 87 pediatric transplant recipients who were evaluated for VUR by VCUG prior to or at the time of the 1-year protocol biopsy and underwent a 1-year protocol biopsy after transplantation. We evaluated the clinicopathological findings of the VUR and non-VUR groups, and histological scores were evaluated using the Banff score. Tamm-Horsfall protein (THP) within the interstitium was identified by light microscopy. RESULTS: Of the 87 transplant recipients, 18 cases (20.7%) were diagnosed with VUR by VCUG. The clinical background and findings were not significantly different between the VUR and non-VUR groups. The pathological findings revealed a significantly higher Banff total interstitial inflammation (ti) score in the VUR group than in the non-VUR group. Multivariate analysis indicated a significant relationship between the Banff ti score and THP within the interstitium, and VUR. The 3-year protocol biopsy results (n = 68) revealed a significantly higher Banff interstitial fibrosis (ci) score in the VUR group than in the non-VUR group. CONCLUSION: VUR caused interstitial fibrosis in the 1-year pediatric protocol biopsies, and interstitial inflammation at the 1-year protocol biopsy may affect interstitial fibrosis at the 3-year protocol biopsy.

Association of clinical characteristics with urine uromodulin in children with chronic kidney disease.

BACKGROUND: Uromodulin is the most abundant protein in the urine of healthy adults, and higher urine concentrations mark better tubular health. Greater kidney size and function are predictors of higher uromodulin levels in adults. Urine uromodulin has not yet been studied in children with chronic kidney disease (CKD). Thus, we sought to determine the relationship between age and kidney function with urine uromodulin levels in children with CKD. METHODS: In the CKD in Children (CKiD) cohort, we utilized multivariable linear regression to evaluate the relationship of age and eGFR with urine uromodulin levels. The primary outcome was uromodulin indexed to urine creatinine (Umod/Cr, mg/g), which was log2-transformed given its skewed distribution. RESULTS: Among 677 CKiD participants, the median age was 11.8 years (8.2-15.3), the median eGFR was 49 ml/min/1.73 m2 (37-63), the etiology of CKD was glomerular disease in 31%, and the median Umod/Cr level was 0.114 mg/g (0.045-0.226). In the multivariable models, each one-year older age was associated with 0.18 (12%) lower log2(Umod/Cr) and 0.20 (13%) lower log2(Umod/Cr) among those with non-glomerular and glomerular disease, respectively (p < 0.001). However, we did not find a statistically significant association between eGFR and Umod/Cr in either participants with non-glomerular or glomerular disease (p = 0.13 and p = 0.58, respectively). CONCLUSIONS: Among children with CKD, older age is significantly associated with lower Umod/Cr, independent of eGFR. Further studies are needed to comprehensively evaluate age-specific reference ranges for urine uromodulin and to evaluate the longitudinal relationship of uromodulin with both age and eGFR in children with CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Biomarkers of eGFR decline after cardiac surgery in children: findings from the ASSESS-AKI study.

BACKGROUND: Children who require surgery for congenital heart disease have increased risk for long-term chronic kidney disease (CKD). Clinical factors as well as urine biomarkers of tubular health and injury may help improve the prognostication of estimated glomerular filtration rate (eGFR) decline. METHODS: We enrolled children from 1 month to 18 years old undergoing cardiac surgery in the ASSESS-AKI cohort. We used mixed-effect models to assess the association between urinary biomarkers (log2-transformed uromodulin, NGAL, KIM-1, IL-18, L-FABP) measured 3 months after cardiac surgery and cyanotic heart disease with the rate of eGFR decline at annual in-person visits over 4 years. RESULTS: Of the 117 children enrolled, 30 (24%) had cyanotic heart disease. During 48 months of follow-up, the median eGFR in the subgroup of children with cyanotic heart disease was lower at all study visits as compared with children with acyanotic heart disease (p = 0.01). In the overall cohort, lower levels of both urine uromodulin and IL-18 after discharge were associated with eGFR decline. After adjustment for age, RACHS-1 surgical complexity score, proteinuria, and eGFR at the 3-month study visit, lower concentrations of urine uromodulin and IL-18 were associated with a monthly decline in eGFR (uromodulin ß = 0.04 (95% CI: 0.00-0.09; p = 0.07) IL-18 ß = 0.07 (95% CI: 0.01-0.13; p = 0.04), ml/min/1.73 m2 per month). CONCLUSIONS: At 3 months after cardiac surgery, children with lower urine uromodulin and IL-18 concentrations experienced a significantly faster decline in eGFR. Children with cyanotic heart disease had a lower median eGFR at all time points but did not experience faster eGFR decline. A higher-resolution version of the Graphical abstract is available as Supplementary information.

Serum Uromodulin, a Potential Biomarker of Tubulointerstitial Damage, Correlates Well with Measured GFR and ERPF in Patients with Obstructive Nephropathy.

Background and Objectives: In chronic kidney obstruction, the severity of tubulointerstitial damage correlates best with the loss of kidney function and the risk for progression to end-stage kidney disease. The present study aimed to investigate the potential clinical significance of serum uromodulin (sUmod) as a marker of early kidney disfunction in patient with obstructive nephropathy (ON). Materials and Methods: Serum Umod level was measured by sensitive ELISA method in 57 adult patients with obstructive nephropathy and 25 healthy subjects in control group. Kidney function was precisely evaluated via measured glomerular filtration rate (mGFR) (renal clearance of 99 mTc-diethylenetriamine penta-acetic acid), effective renal plasma flow (ERPF) and Cystatin C level. Recruited patients were divided into subgroups based on the mGFR: group I­GFR ≤ 60 mL/min/1.73 m2 (N = 31), group II­GFR > 60 mL/min/1.73 m2 (N = 26). Results: A significantly lower level of serum uromodulin was measured in patients with ON (50.2 ± 26.3 ng/mL) compared to the control group (78.3 ± 24.5 ng/mL) (p < 0.001). The mean level of serum Umod was significantly different between group I (30.5 ng/mL ± 11.1) and group II (73.6 ng/mL ± 18.6) (p < 0.001), but not between group II (73.6 ng/mL ± 18.6) and control group (78.3 ± 24.5 ng/mL). There was a positive correlation between sUmod and mGFR (R = 0.757, p < 0.001) and ERPF (R = 0.572 p < 0.001), with lower sUmod levels in patients with impaired renal function. An inverse relationship was detected between sUmod and filtration markers­cystatin C (R = −0.625, p < 0.001), creatinine, urea and uric acid. ROC analysis of sUmod to differentiate between ON patients with GFR below 60 mL/min/1.73 m2 and above 60 mL/min/1.73 m2 resulted in AUC of 0.98 (p < 0.001, 95% CI 0.922 vs. 0.998) at a cut-off value of 46 ng/mL (specificity 96.8%, sensitivity 92.2%). Conclusions: The significant correlation of sUmod with kidney function parameters may imply potential clinical significance as a noninvasive biomarker of early kidney disfunction in obstructive nephropathy.

The Effect of miR-505-5p on Inhibition of Serum Uromodulin Ameliorates Myocardial Inflammation and Apoptosis Induced by Ischemia-Reperfusion.

Background: It has been found that miR-505-5p is closely related to cardiovascular metabolic risk factors. Nonetheless, there is little research analyzing miR-505-5p for its role as well as molecular mechanism in myocardial injury caused by ischemia-reperfusion (I/R). Methods: This work utilized quantitative reverse transcriptase PCR (qRT-PCR) for detecting miR-505-5p and serum uromodulin (sUmod) levels. sUmod, interleukin-1beta (IL-1ß), IL-6, IL-10, caspase7, caspase9, tumor necrosis factor-alpha (TNF-α), Bax, and Bcl-xL expression was detected by western blot. Bioinformatics database was used for target prediction and miR-505-5's target was determined by luciferase reporter gene assay. Results: Relative to sham group, sUmod was highly expressed within myocardial I/R injury (MIRI), whereas sUmod silencing significantly decreased the heart weight/body weight ratio, reduced serum myocardial enzymes expression, ameliorated I/R-mediated myocardial apoptosis, and inflammation. TargetScan bioinformatics database and luciferase reporter genes confirmed that sUmod was miR-505-5p's direct target gene, besides, miR-505-5p overexpression significantly improved the myocardial injury score, increased IL-10, decreased TNF-α, IL-1ß, IL-6 expression, decreased caspase7, caspase9, Bax expression, and increased Bcl-xL expression. More importantly, overexpression of sUmod abolished miR-505-5p overexpression's role in I/R-mediated myocardial apoptosis and inflammation. Conclusion: miR-505-5p can improve I/R-mediated myocardial apoptosis and inflammation by targeting sUmod. In this study, miR-505-5p is related to MIRI pathogenesis, which provides the new possible targeted therapy in patients with MIRI.

Evaluation of Early Renal Involvement in Essential Hypertension by Measuring Urinary Biomarkers.

Hypertensive kidney damage results in glomerular as well as tubular dysfunction. Albuminuria is a well-known marker of glomerular damage. On the other hand, urinary uromodulin is increasingly considered as a potential biomarker of early tubular dysfunction. The aim of the study was to assess glomerular and tubular function of the kidney by measuring urinary albumin and uromodulin excretion in hypertensive subjects. This cross-sectional study was conducted from July 2018 to June 2019 in Hypertension Clinic of Dhaka Medical College Hospital, Dhaka and Kidney Care and Research Centre, Sonargaon, Narayanganj, Bangladesh. In this study 122 hypertensive subjects with age >30 years, duration of hypertension <5 years, without accelerated or malignant BP, absence of dipstick proteinuria and eGFR >60ml/min were included. There were also 33 normotensive individuals included as healthy controls. Albumin-creatinine ratio (uACR mg/g), urine uromodulin-creatinine ratio (uUMODµg/g), urinary sodium-creatinine ratio (mEq/g) and potassium-creatinine ratio (mEq/g) were measured from single morning spot urine sample. Urinary uromodulin levels were measured by ELISA method. The hypertensive and normotensive subjects were age matched 49.0±12.0 vs. 48.0±11.0, years (p=NS). The mean uACR was 29.0±65.0 versus 5.6±2.7mg/g, (p<0.001) respectively. The median uUMOD in hypertensive subjects was 3.38 (1.73-9.06) and in normotensives 3.85(2.28-5.69) µg/g (p=non significant). Multivariate analysis showed significant inverse association between diastolic blood pressure and urinary uromodulin excretion. A uUMOD cut-off of 2.9 (25th percentile) showed eGFR, urinary sodium and potassium excretions were significantly lower at low uromodulin group. The glomerular involvement was found in 21.0% of hypertensive subjects as evidenced by albuminuria. No difference was observed in urinary uromodulin level between hypertensive and normotensive subjects. Low urinary uromodulin level was associated with lower eGFR, Na+ and K+ excretion which indicate simultaneous tubular and glomerular involvement.

Olfactomedin 4 as a novel loop of Henle-specific acute kidney injury biomarker.

Acute kidney injury (AKI) is associated with morbidity and mortality. Urinary biomarkers may disentangle its clinical heterogeneity. Olfactomedin 4 (OLFM4) is a secreted glycoprotein expressed in stressed neutrophils and epithelial cells. In septic mice, OLFM4 expression localized to the kidney's loop of Henle (LOH) and was detectable in the urine. We hypothesized that urine OLFM4 (uOLFM4) will be increased in patients with AKI and sepsis. Urine from critically ill pediatric patients was obtained from a prospective study based on AKI and sepsis status. uOLFM4 was quantified with a Luminex immunoassay. AKI was defined by KDIGO severe criteria. Sepsis status was extracted from the medical record based on admission diagnosis. Immunofluorescence on pediatric kidney biopsies was performed with NKCC2, uromodulin and OLFM4 specific antibodies. Eight patients had no sepsis, no AKI; 7 had no sepsis but did have AKI; 10 had sepsis, no AKI; 11 had sepsis and AKI. Patients with AKI had increased uOLFM4 compared to no/stage 1 AKI (p = 0.044). Those with sepsis had increased uOLFM4 compared to no sepsis (p = 0.026). uOLFM4 and NGAL were correlated (r2 0.59, 95% CI 0.304-0.773, p = 0.002), but some patients had high uOLFM4 and low NGAL, and vice versa. Immunofluorescence on kidney biopsies demonstrated OLFM4 colocalization with NKCC2 and uromodulin, suggesting expression in the thick ascending LOH (TALH). We conclude that AKI and sepsis are associated with increased uOLFM4. uOLFM4 and NGAL correlated in many patients, but was poor in others, suggesting these markers may differentiate AKI subgroups. Given OLFM4 colocalization to human TALH, we propose OLFM4 may be a LOH-specific AKI biomarker.

Urine Uromodulin as a Biomarker of Kidney Tubulointerstitial Fibrosis.

BACKGROUND AND OBJECTIVES: Uromodulin, produced exclusively in the kidney's thick ascending limb, is a biomarker of kidney tubular health. However, the relationship between urine uromodulin and histologic changes in the kidney tubulointerstitium has not been characterized. In this study, we test the association of urine uromodulin with kidney histologic findings in humans and mice. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We investigated the independent association of urine uromodulin measured at the time of kidney biopsy with histologic features in 364 participants at two academic medical centers from 2015 to 2018 using multivariable linear regression models. This relationship was further examined by comparison of uromodulin staining in murine models of kidney fibrosis and repair. RESULTS: We found urine uromodulin to be correlated with serum creatinine (rho=-0.43; P<0.001), bicarbonate (0.20; P<0.001), and hemoglobin (0.11; P=0.03) at the time of biopsy but not with urine albumin (-0.07; P=0.34). Multivariable models controlling for prebiopsy GFR, serum creatinine at biopsy, and urine albumin showed higher uromodulin to be associated with lower severity of interstitial fibrosis/tubular atrophy and glomerulosclerosis (interstitial fibrosis/tubular atrophy: -3.5% [95% confidence intervals, -5.7% to -1.2%] and glomerulosclerosis: -3.3% [95% confidence intervals, -5.9% to -0.6%] per two-fold difference in uromodulin). However, when both interstitial fibrosis/tubular atrophy and glomerulosclerosis were included in multivariable analysis, only interstitial fibrosis/tubular atrophy was independently associated with uromodulin (interstitial fibrosis/tubular atrophy: -2.5% [95% confidence intervals, -4.6% to -0.4%] and glomerulosclerosis: -0.9% [95% confidence intervals, -3.4% to 1.5%] per two-fold difference in uromodulin). In mouse kidneys, uromodulin staining was found to be lower in the fibrotic model than in normal or repaired models. CONCLUSIONS: Higher urine uromodulin is independently associated with lower tubulointerstitial fibrosis in both human kidney biopsies and a mouse model of fibrosis. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_08_10_CJN04360422.mp3.

Serum Uromodulin Levels Reflect Severity of Clinicopathological Findings in Early Stage IgA Nephropathy.

INTRODUCTION: Uromodulin (UMOD), also known as Tamm-Horsfall protein, is a kidney-specific protein. Recently, low levels of urinary UMOD (uUMOD) have been reported as a risk factor for renal function decline in IgA nephropathy (IgAN). However, the clinical significance of serum UMOD (sUMOD) is not clear. In this study, we clarified the clinical significance of sUMOD in IgAN. METHODS: One hundred eight biopsy-proven IgAN patients were included in this study. The relationships between sUMOD levels and various clinicopathological findings were evaluated. RESULTS: sUMOD was positively correlated with estimated glomerular filtration rate (eGFR) (p < 0.001, r = 0.5) and negatively correlated with creatinine (Cr) (p < 0.0001, r = -0.51) and urinary protein (UP) (p = 0.005, r = -0.33). In the low sUMOD group (<145 ng/mL), Cr was significantly higher (p < 0.0001) and histopathological changes were severe. The cumulative incidence of a 30% decline in eGFR was 25.6% overall, 0% in histological grade (H-G) I, 33.3% in H-G II, 59.6% in H-G III, and 66.7% in H-G IV. In univariate analyses, prognostic factors for a 30% decline in eGFR were male, high UP, low albumin, low eGFR, and low sUMOD. When comparing the severe histopathological classes (H-G II-IV) and H-G I, low sUMOD was a risk factor for severe histopathological changes. Furthermore, in patients with eGFR > 60 (n = 74), multivariate analyses revealed that low sUMOD independently predicted a 30% decline in eGFR and having severe histopathological changes. CONCLUSION: In IgAN, sUMOD levels were associated with renal function. Low sUMOD levels may be a risk factor for worsening renal function, especially in the early stage of IgAN.

Lamprey immunity protein enables early detection and recurrence monitoring for bladder cancer through recognizing Neu5Gc-modified uromodulin glycoprotein in urine.

The clinical management of bladder cancer (BCa) is hindered by the lack of reliable biomarkers. We aimed to investigate the potential of lamprey immunity protein (LIP), a lectin that specifically binds to multi-antennary sialylated N-glycolylneuraminic acid (Neu5Gc) structures on UMOD glycoproteins in the urine of BCa patients. Primary BCa patients had higher levels of LIP-bound Neu5Gc in urine than healthy participants and patients receiving postoperative treatment did. In addition, lectin chip assay and mass spectrometry were used to analyze the glycan chain structure, which can recognize the UMOD glycoprotein decorated with multi-antennary sialylated Neu5Gc structures. Furthermore, compared with urine samples from healthy patients (N = 2821, T/C = 0.12 ± 0.09) or benign patients (N = 360, T/C = 0.11 ± 0.08), the range of the urine T/C ratio detected using LIP test paper was 1.97 ± 0.32 in patients with bladder cancer (N = 518) with significant difference (P < 0.0001). Our results indicate that LIP may be a tool for early BCa identification, diagnosis, and monitoring. Neu5Gc-modified UMOD glycoproteins in urine and Neu5Gc-modified N-glycochains and sialyltransferases may function as potential markers in clinical trials.

Decreased preoperative urinary uromodulin as a predictor of acute kidney injury and perioperative kidney dysfunction in patients undergoing cardiac surgery: A prospective cohort study.

BACKGROUND: Acute kidney injury (AKI) is a major complication following cardiac surgery that substantially increases mortality. We explored the clinical utility of urinary uromodulin (uUMOD), a marker of renal tubular reserve, for preoperative identification of patients at risk for AKI and perioperative kidney dysfunction. METHODS: This prospective observational study included patients who underwent cardiac surgery between December 2019 and January 2021. AKI was defined according to the Kidney Disease Improving Global Outcomes criteria; perioperative kidney dysfunction was accessed using a longitudinal estimated glomerular filtration rate. RESULTS: A total of 409 participants were enrolled. Patients with uUMOD ≤ 20.7 µg/mL were associated with a higher risk for AKI (odds ratio, 3.24; 95% confidence interval: 1.87-5.63, P < 0.001), independent of baseline kidney function. The uUMOD exhibits adequate discrimination for predicting AKI, with an area under the receiver operating characteristic curve of 0.713 (95% confidence interval: 0.652-0.773), and has well-fitted calibration (Hosmer-Lemeshow goodness-of-fit test, P = 0.163). The trajectory analysis revealed that decreased uUMOD levels were linked to a higher risk of patients being assigned to a worse perioperative kidney function cluster. CONCLUSIONS: Decreased preoperative uUMOD is independently associated with an increased risk of AKI and perioperative kidney dysfunction after cardiac surgery.

Pathophysiological aspects of the thick ascending limb and novel genetic defects: HELIX syndrome and transient antenatal Bartter syndrome.

The thick ascending limb plays a central role in human kidney physiology, participating in sodium reabsorption, urine concentrating mechanisms, calcium and magnesium homeostasis, bicarbonate and ammonium homeostasis, and uromodulin synthesis. This review aims to illustrate the importance of these roles from a pathophysiological point of view by describing the interactions of the key proteins of this segment and by discussing how recently identified and long-known hereditary diseases affect this segment. The descriptions of two recently described salt-losing tubulopathies, transient antenatal Bartter syndrome and HELIX syndrome, which are caused by mutations in MAGED2 and CLDN10 genes, respectively, highlight the role of new players in the modulation of sodium reabsorption the thick ascending limb.

Kidney tubule health, mineral metabolism and adverse events in persons with CKD in SPRINT.

BACKGROUND: Measures of kidney tubule health are risk markers for acute kidney injury (AKI) in persons with chronic kidney disease (CKD) during hypertension treatment, but their associations with other adverse events (AEs) are unknown. METHODS: Among 2377 Systolic Blood Pressure Intervention Trial (SPRINT) participants with CKD, we measured at baseline eight urine biomarkers of kidney tubule health and two serum biomarkers of mineral metabolism pathways that act on the kidney tubules. Cox proportional hazards models were used to evaluate biomarker associations with risk of a composite of pre-specified serious AEs (hypotension, syncope, electrolyte abnormalities, AKI, bradycardia and injurious falls) and outpatient AEs (hyperkalemia and hypokalemia). RESULTS: At baseline, the mean age was 73 ± 9 years and mean estimated glomerular filtration rate (eGFR) was 46 ± 11 mL/min/1.73 m2. During a median follow-up of 3.8 years, 716 (30%) participants experienced the composite AE. Higher urine interleukin-18, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin (NGAL) and monocyte chemoattractant protein-1 (MCP-1), lower urine uromodulin (UMOD) and higher serum fibroblast growth factor-23 were individually associated with higher risk of the composite AE outcome in multivariable-adjusted models including eGFR and albuminuria. When modeling biomarkers in combination, higher NGAL [hazard ratio (HR) = 1.08 per 2-fold higher biomarker level, 95% confidence interval (CI) 1.03-1.13], higher MCP-1 (HR = 1.11, 95% CI 1.03-1.19) and lower UMOD (HR = 0.91, 95% CI 0.85-0.97) were each associated with higher composite AE risk. Biomarker associations did not vary by intervention arm (P > 0.10 for all interactions). CONCLUSIONS: Among persons with CKD, several kidney tubule biomarkers are associated with higher risk of AEs during hypertension treatment, independent of eGFR and albuminuria.

Autosomal dominant tubulointerstitial kidney disease: more than just HNF1ß.

Autosomal dominant tubulointerstitial kidney disease (ADTKD) refers to a group of disorders with a bland urinary sediment, slowly progressive chronic kidney disease (CKD), and autosomal dominant inheritance. Due to advances in genetic diagnosis, ADTKD is becoming increasingly recognized as a cause of CKD in both children and adults. ADTKD-REN presents in childhood with mild hypotension, CKD, hyperkalemia, acidosis, and anemia. ADTKD-UMOD is associated with gout and CKD that may present in adolescence and slowly progresses to kidney failure. HNF1ß mutations often present in childhood with anatomic abnormalities such as multicystic or dysplastic kidneys, as well as CKD and a number of other extra-kidney manifestations. ADTKD-MUC1 is less common in childhood, and progressive CKD is its sole clinical manifestation, usually beginning in the late teenage years. This review describes the pathophysiology, genetics, clinical characteristics, diagnosis, and treatment of the different forms of ADTKD, with an emphasis on diagnosis. We also present data on kidney function in children with ADTKD from the Wake Forest Rare Inherited Kidney Disease Registry.