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Early biochemical identification of women at high risk for the development of pre-eclampsia (PE) is still unsatisfactory. Renal markers measured during the first trimester were analysed to predict later occurrence of PE. A nested case-control study was conducted within the prospective predictive markers for the diagnosis of preeclampsia study. Pregnant women were included at the end of the first trimester and followed up until birth. Controls were matched to PE cases. Renal markers [i.e. creatinine, cystatin C (CysC), β2microglobulin (B2M), β-trace protein (BTP), glomerular filtration rate estimations (eGFR) of the aforementioned markers, uric acid (UA), urea, and serum uromodulin (sUMOD)] were compared to placental growth factor (PlGF), a marker known to predict PE later in pregnancy. Reference intervals were determined for the different markers. In the 183 women (PE,n = 39; controls,n = 144), CysC, the CysC/PlGF ratio (p < .01) and UA were higher, whereas the eGFRCysC/eGFRCrearatio (a marker of glomerular endothelial integrity and shrunken pore syndrome) and PlGF were lower in women who developed PE (p < .05 for all). Compromised filtration of the larger molecule CysC together with a normal creatinine, in a subset of PE cases (15.3%) was a unique, strong and independent predictor of later PE if the baseline CysC concentration was >0.85 mg/l. In conclusion, CysC and its derivatives as well as UA, indicating volume expansion, measured at the end of the first trimester are predictive of PE. Thus, women can be easily identified and followed as an early reduction in glomerular filtration quality poses a high risk for a subsequent development of PE. [ABSTRACT FROM PUBLISHER]

Hereditary mutations in Tamm-Horsfall protein (THP/uromodulin) gene cause autosomal dominant kidney diseases characterized by juvenile-onset hyperuricemia, gout and progressive kidney failure, although the disease pathogenesis remains unclear. Here we show that targeted expression in transgenic mice of a mutation within the domain of 8 cysteines of THP in kidneys’ thick ascending limb (TAL) caused unfolded protein response in younger (1-month old) mice and apoptosis in older (12-month old) mice. While the young mice had urine concentration defects and polyuria, such defects progressively reversed in the older mice to marked oliguria, highly concentrated urine, fibrotic kidneys and reduced creatinine clearance. Both the young and the old transgenic mice had significantly higher serum uric acid and its catabolic product, allantoin, than age-matched wild-type mice. This THP mutation apparently caused primary defects in TAL by compromising the luminal translocation and reabsorptive functions of NKCC2 and ROMK and secondary responses in proximal tubules by upregulating NHE3 and URAT1. Our results strongly suggest that the progressive worsening of kidney functions reflects the accumulation of the deleterious effects of the misfolded mutant THP and the compensatory responses. Transgenic mice recapitulating human THP/uromodulin-associated kidney diseases could be used to elucidate their pathogenesis and test novel therapeutic strategies. [ABSTRACT FROM AUTHOR]

Background & objectives: Uromodulin, a UMOD gene encoded glycoprotein is synthesized exclusively in renal tubular cells and released into urine. Mutations lead to uromodulin misfolding and retention in the kidney, where it might stimulate cells of immune system to cause inflammation and progression of kidney disease. Genome-wide association studies (GWAS) have identified UMOD locus to be associated with hypertension and diabetic nephropathy (DN). In this study, we investigated the association between rs4293393 variation in UMOD gene and susceptibility to kidney disease in individuals with type 2 diabetes mellitus (T2DM). Methods: A total of 646 individuals, 208 with T2DM without evidence of kidney disease (DM), 221 with DN and 217 healthy controls (HC) were genotyped for UMOD variant rs4293393T>C by restriction fragment length polymorphism. Serum uromodulin levels were quantified by enzyme-linked immunosorbent assay. Results: A significant difference was found in genotype and allelic frequency among DM, DN and HC. TC+CC genotype and C allele were found more frequently in DN compared to HC (33.9 vs 23.0%, P=0.011 and 20.1 vs 12.9%, P=0.004, respectively). Compared to DM, C allele was found to be more frequent in individuals with DN (20.1 vs 14.7%, P=0.034). Those with DN had higher serum uromodulin levels compared to those with DM (P=0.001). Serum uromodulin levels showed a positive correlation with serum creatinine (r=0.431; P<0.001) and negative correlation with estimated glomerular filtration rate (r=-0.423; P<0.001). Interpretation & conclusions: The frequency of UMOD rs4293393 variant with C allele was significantly higher in individuals with DN. UMOD rs4293393 T>C variation might have a bearing on susceptibility to nephropathy in north Indian individuals with type 2 diabetes. [ABSTRACT FROM AUTHOR]

Uromodulin-associated kidney disease (UAKD) is caused by mutations in the uromodulin (UMOD) gene that result in a misfolded form of UMOD protein, which is normally secreted by nephrons. In UAKD patients, mutant UMOD is poorly secreted and accumulates in the ER of distal kidney epithelium, but its role in disease progression is largely unknown. Here, we modeled UMOD accumulation in mice by expressing the murine equivalent of the human UMOD p.Cys148Trp point mutation (UmodC147W/+ mice). Like affected humans, these UmodC147W/+ mice developed spontaneous and progressive kidney disease with organ failure over 24 weeks. Analysis of diseased kidneys and purified UMOD-producing cells revealed early activation of the PKR-like ER kinase/activating transcription factor 4 (PERK/ATF4) ER stress pathway, innate immune mediators, and increased apoptotic signaling, including caspase-3 activation. Unexpectedly, we also detected autophagy deficiency. Human cells expressing UMOD p.Cys147Trp recapitulated the findings in UmodC147W/+ mice, and autophagy activation with mTOR inhibitors stimulated the intracellular removal of aggregated mutant UMOD. Human cells producing mutant UMOD were susceptible to TNF-α- and TRAIL-mediated apoptosis due to increased expression of the ER stress mediator tribbles-3. Blocking TNF-α in vivo with the soluble recombinant fusion protein TNFR:Fc slowed disease progression in UmodC147W/+ mice by reducing active caspase-3, thereby preventing tubule cell death and loss of epithelial function. These findings reveal a targetable mechanism for disease processes involved in UAKD. [ABSTRACT FROM AUTHOR]

Autosomal Dominant Tubulointerstitial Kidney Diseases (ADTKD) are a group of autosomal dominant hereditary nephropathies which share a rather aspecific pathological picture of interstitial fibrosis and tubular atrophy (IFTA) and a slowly progressing tubulointerstitial clinical profile: end-stage renal disease (ESRD) generally occurs between 30 and 50 years. Four types of ADTKD have been described so far, each showing some peculiarities: hepatocyte nuclear factor-1 β (HNF1β) ADTKD, in which ADTKD can be associated with renal cysts and a wide spectrum of congenital abnormalities of kidney and urinary tract (CAKUT) and extra-renal manifestations (diabetes, liver enzyme alterations, genital malformations), uromodulin (UMOD) ADTKD, characterised by early onset of hyperuricemia and gout, mucin-1 (MUC-1) ADTKD, a recently discovered form which appears to be an isolated tubulointerstitial nephropathy, and renin (REN) ADTKD, which appears in childhood and is characterised by anemia and mild signs of hyporeninism. A better awareness is needed in order to perform genetic analysis whenever clinical setting is compatible with this nephropathy. A timely diagnosis can have an important impact on both the patient and his family members in terms of therapy and prognosis, also at the prospect of renal transplant. [ABSTRACT FROM AUTHOR]

Uromodulin (also known as Tamm-Horsfall protein) is exclusively produced in the kidney and is the most abundant protein in normal urine. The function of uromodulin remains elusive, but the available data suggest that this protein might regulate salt transport, protect against urinary tract infection and kidney stones, and have roles in kidney injury and innate immunity. Interest in uromodulin was boosted by genetic studies that reported involvement of the UMOD gene, which encodes uromodulin, in a spectrum of rare and common kidney diseases. Rare mutations in UMOD cause autosomal dominant tubulointerstitial kidney disease (ADTKD), which leads to chronic kidney disease (CKD). Moreover, genome-wide association studies have identified common variants in UMOD that are strongly associated with risk of CKD and also with hypertension and kidney stones in the general population. These findings have opened up a new field of kidney research. In this Review we summarize biochemical, physiological, genetic and pathological insights into the roles of uromodulin; the mechanisms by which UMOD mutations cause ADTKD, and the association of common UMOD variants with complex disorders. [ABSTRACT FROM AUTHOR]

Bacterial access to the gut immune system is a crucial process to promote host immune responses. The probiotic L-92 strain of Lactobacillus acidophilus exerts anti-allergic immunomodulatory effects upon oral administration in mice. Here, we show that microfold cells (M cells) are responsible for L-92 internalization for evoking L-92-mediated immune responses. L-92 specifically bound to uromodulin, a glycosylphosphatidylinositol-anchored protein expressed exclusively on M cells among intestinal epithelial cells. Internalization of L-92 into M cells was significantly reduced in uromodulin-deficient (Umod-/-) mice compared to Umod+/+ mice. Furthermore, the binding of L-92 to uromodulin was significantly decreased after removal of surface layer protein A (SlpA) from the bacteria. Our study thus revealed a crucial role of uromodulin on the M-cell surface for the uptake of SlpA-positive lactic acid bacteria into M cells, possibly leading to subsequent delivery of the bacteria to dendritic cells closely associated with M cells for immunomodulation. Our study also shed light on the possibility that SlpA and uromodulin could be used as vehicle and target, respectively, for efficient mucosal vaccine delivery. [ABSTRACT FROM AUTHOR]

In its early stages, symptoms of chronic kidney disease (CKD) are usually not apparent. Significant reduction of the kidney function is the first obvious sign of disease. If diagnosed early (stages 1 to 3), the progression of CKD can be altered and complications reduced. In stages 4 and 5 extensive kidney damage is observed, which usually results in end-stage renal failure. Currently, the diagnosis of CKD is made usually on the levels of blood urea and serum creatinine (sCr), however, sCr has been shown to be lacking high predictive value. Due to the development of genomics, epigenetics, transcriptomics, proteomics, and metabolomics, the introduction of novel techniques will allow for the identification of novel biomarkers in renal diseases. This review presents some new possible biomarkers in the diagnosis of CKD and in the prediction of outcome, including asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), uromodulin, kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), miRNA, ncRNA, and lincRNA biomarkers and proteomic and metabolomic biomarkers. Complicated pathomechanisms of CKD development and progression require not a single marker but their combination in order to mirror all types of alterations occurring in the course of this disease. It seems that in the not so distant future, conventional markers may be exchanged for new ones, however, confirmation of their efficacy, sensitivity and specificity as well as the reduction of analysis costs are required. [ABSTRACT FROM AUTHOR]

Many urine proteins are found in calcium oxalate stones, yet decades of research have failed to define the role of urine proteins in stone formation. This urine proteomic study compares the relative amounts of abundant urine proteins between idiopathic calcium oxalate stone forming and non-stone forming (normal) cohorts to identify differences that might correlate with disease. Random mid-morning urine samples were collected following informed consent from 25 stone formers and 14 normal individuals. Proteins were isolated from urine using ultrafiltration. Urine proteomes for each sample were characterized using label-free spectral counting mass spectrometry, so that urine protein relative abundances could be compared between the two populations. A total of 407 unique proteins were identified with the 38 predominant proteins accounting for >82% of all sample spectral counts. The most highly abundant proteins were equivalent in stone formers and normals, though significant differences were observed in a few moderate abundance proteins (immunoglobulins, transferrin, and epidermal growth factor), accounting for 13 and 10% of the spectral counts, respectively. These proteins contributed to a cationic shift in protein distribution in stone formers compared to normals (22% vs. 18%, p = 0.04). Our data showing only small differences in moderate abundance proteins suggest that no single protein controls stone formation. Observed increases in immunoglobulins and transferrin suggest increased inflammatory activity in stone formers, but cannot distinguish cause from effect in stone formation. The observed cationic shift in protein distribution would diminish protein charge stabilization, which could lead to protein aggregation and increased risk for crystal aggregation. [ABSTRACT FROM AUTHOR]

Advanced glycation end-products (AGEs) form during oxidative stress, which is increased in diabetes mellitus (DM). Uromodulin is a protein with a renal protective effect, and may be subject to glycation. The implications of uromodulin glycation and AGEs in the urine are not understood. Here, immunoprecipitation and liquid chromatography-mass spectrometry identified glycated uromodulin (glcUMOD) in the urine of 62.5% of patients with diabetic kidney disease (DKD), 20.0% of patients with non-diabetic chronic kidney disease (CKD), and no DM patients with normal renal function or healthy control participants; a finding replicated in a larger cohort of 84 patients with CKD in a case-control study (35 with DM, 49 without). Uromodulin forms high molecular weight polymers that associate with microvesicles and exosomes. Differential centrifugation identified uromodulin in the supernatant, microvesicles, and exosomes of the urine of healthy participants, but only in the supernatant of samples from patients with DKD, suggesting that glycation influences uromodulin function. Finally, the diagnostic and prognostic utility of measuring urinary glcUMOD concentration was examined. Urinary glcUMOD concentration was substantially higher in DKD patients than non-diabetic CKD patients. Urinary glcUMOD concentration predicted DKD status, particularly in patients with CKD stages 1-3a aged <65 years and with urine glcUMOD concentration ⩾9,000 arbitrary units (AU). Urinary uromodulin is apparently glycated in DKD and forms AGEs, and glcUMOD may serve as a biomarker for DKD. [ABSTRACT FROM AUTHOR]

Tamm-Horsfall protein (THP) is an abundant urinary protein of renal origin. We hypothesize that THP can act as an inhibitor of complement since THP binds complement 1q (C1q) of the classical complement pathway, inhibits activation of this pathway, and is important in decreasing renal ischemia-reperfusion injury (a complement-mediated condition). In this study, we began to investigate whether THP interacted with the alternate complement pathway via complement factor H (CFH). THP was shown to bind CFH using ligand blots and in an ELISA (KD of 1 × 10−6 M). Next, the ability of THP to alter CFH’s normal action as it functioned as a cofactor in complement factor I (CFI)–mediated complement 3b (C3b) degradation was investigated. Unexpectedly, control experiments in these in vitro assays suggested that THP, without added CFH, could act as a cofactor in CFI-mediated C3b degradation. This cofactor activity was present equally in THP isolated from 10 different individuals. While an ELISA demonstrated small amounts of CFH contaminating THP samples, these CFH amounts were insufficient to explain the degree of cofactor activity present in THP. An ELISA demonstrated that THP directly bound C3b (KD ~ 5 × 10−8 , a prerequisite for a protein acting as a C3b degradation cofactor. The cofactor activity of THP likely resides in the protein portion of THP since partially deglycosylated THP still retained cofactor activity. In conclusion, THP appears to participate directly in complement inactivation by its ability to act as a cofactor for C3b degradation, thus adding support to the hypothesis that THP might act as an endogenous urinary tract inhibitor of complement. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Proteinuria is a marker and mediator of chronic kidney disease (CKD). In clinical practice, the urinary protein-to-creatinine ratio (UP/C) is of limited usefulness, because it indicates only the magnitude of proteinuria and not the origin of the loss (glomerular or tubular). The complete assessment of proteinuria includes quantitative and qualitative evaluations, both of which are required in order to optimize the therapy. In addition to measuring the UP/ C, we performed SDS-PAGE and western blotting to determine the expression of albumin, vitamin D-binding protein (VDBP), retinol-binding protein (RBP), and Tamm-Horsfall protein (THP) in urine samples of 49 dogs: healthy (control) dogs (n = 9); and dogs with CKD (n = 40), stratified by stage. In the dogs with stage 3 or 4 CKD, there was a predominance of tubular proteins. Neither VDBP nor RBP was observed in the urine of the control dogs. Among the dogs with stage 1 or 2 CKD, VDBP and RBP were detected in those without proteinuria or with borderline proteinuria. The expression of urinary albumin was significantly higher in the stage 4 group than in any other group (P ≤ 0.01). In the stage 4 group, urinary THP was either undetectable or lower than in the control group (P ≤ 0.01). In conclusion, urinary VDBP and RBP might act as early markers of kidney injury, and a decrease in urinary THP could be an indicator of CKD progression. [ABSTRACT FROM AUTHOR]

The kidney is centrally involved in blood pressure regulation and undergoes extensive changes during pregnancy. Hypertension during pregnancy may result in an altered urinary peptidome that could be used to indicate new targets of therapeutic or diagnostic interest. The stroke-prone spontaneously hypertensive rat (SHRSP) is a model of maternal chronic hypertension. Capillary electrophoresis-mass spectrometry was conducted to interrogate the urinary peptidome in SHRSP and the control Wistar-Kyoto strain at three time points: prepregnancy and gestational days 12 and 18. The comparison within and between the Wistar-Kyoto and SHRSP peptidome at all time points detected 123 differentially expressed peptides (fold change >1.5; P<0.05). Sequencing of these peptides identified fragments of collagen α-chains, albumin, prothrombin, actin, serpin A3K, proepidermal growth factor, and uromodulin. Uromodulin peptides showed a pregnancy-specific alteration in SHRSP with a 7.8-fold (P<0.01) and 8.8-fold (P<0.05) increase at gestational days 12 and 18, respectively, relative to the Wistar-Kyoto. Further investigation revealed that these peptides belonged to the polymerization-inhibitory region of uromodulin. Two forms of uromodulin (polymerization competent and polymerization incompetent) were found in urine from both Wistar-Kyoto and SHRSP, where the polymerization-incompetent form was increased in a pregnancy-specific manner in SHRSP. Nifedipine-treated pregnant SHRSP showed only polymerization-competent uromodulin, indicating that calcium may be mechanistically involved in uromodulin polymerization. This study highlights, for the first time, a potential role of uromodulin and its polymerization in hypertensive pregnancy. [ABSTRACT FROM AUTHOR]

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Uromodulin is the most abundant urinary protein in physiological conditions. It is exclusively produced by renal epithelial cells lining the thick ascending limb of Henle’s loop (TAL) and it plays key roles in kidney function and disease. Mutations in UMOD, the gene encoding uromodulin, cause autosomal dominant tubulointerstitial kidney disease uromodulin-related (ADTKD-UMOD), characterised by hyperuricemia, gout and progressive loss of renal function. While the primary effect of UMOD mutations, retention in the endoplasmic reticulum (ER), is well established, its downstream effects are still largely unknown. To gain insight into ADTKD-UMOD pathogenesis, we performed transcriptional profiling and biochemical characterisation of cellular models (immortalised mouse TAL cells) of robust expression of wild type or mutant GFP-tagged uromodulin. In this model mutant uromodulin accumulation in the ER does not impact on cell viability and proliferation. Transcriptional profiling identified 109 genes that are differentially expressed in mutant cells relative to wild type ones. Up-regulated genes include several ER resident chaperones and protein disulphide isomerases. Consistently, pathway enrichment analysis indicates that mutant uromodulin expression affects ER function and protein homeostasis. Interestingly, mutant uromodulin expression induces the Unfolded Protein Response (UPR), and specifically the IRE1 branch, as shown by an increased splicing of XBP1. Consistent with UPR induction, we show increased interaction of mutant uromodulin with ER chaperones Bip, calnexin and PDI. Using metabolic labelling, we also demonstrate that while autophagy plays no role, mutant protein is partially degraded by the proteasome through ER-associated degradation. Our work demonstrates that ER stress could play a central role in ADTKD-UMOD pathogenesis. This sets the bases for future work to develop novel therapeutic strategies through modulation of ER homeostasis and associated protein degradation pathways. [ABSTRACT FROM AUTHOR]

Background Uromodulin is a protein produced exclusively by the kidneys and present in urine and blood. In contrast to weak and in part contradictory study data on uromodulin in urine samples, the analysis of serum samples recently proved uromodulin's value as superior biomarker for ongoing kidney disease. Whether serum uromodulin is associated with cardiovascular event risk and whether it has predictive power for overall mortality is still unknown and has been evaluated in the present study. Methods We measured uromodulin in a series of 529 patients without acute coronary syndrome undergoing coronary angiography for the evaluation of established or suspected stable coronary artery disease (CAD) and prospectively recorded mortality as well as cardiovascular events in our patients during a follow-up of up to 8 years. Results We recorded 95 deaths and 145 cardiovascular events over 8 years. Serum uromodulin proved protective for overall mortality (HR = 0.56 [95%CI 0.43–0.72]; p < 0.001), even after full adjustment including eGFR, current smoking, diabetes, and CAD status (adj. HR = 0.57 [95%CI 0.37–0.89]; p = 0.014). Patients in the lowest tertile of serum uromodulin had a significantly higher cardiovascular event risk compared to patients in the medium and highest tertile (HR = of 1.45 (95%CI 1.04–2.02, p = 0.027). The ratio between creatinine and uromodulin was significantly associated with kidney function (r = − 0.322; p < 0.001) and significantly predicted the incidence of cardiovascular events (HR of 1.26 [95%CI 1.12–1.41], p < 0.001) and major cardiovascular events (HR of 1.37 [95%CI 1.21–1.56], p < 0.001). Conclusion We conclude that serum uromodulin is a valuable biomarker to predict overall mortality and cardiovascular events. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Urinary extracellular vesicles (EVs) are a promising source of biomarkers, which can be obtained in a non-invasive manner. However, the yield of EVs from urine samples may be insufficient for various analyses due to the entrapment of EVs by the Tamm-Horsfall protein (THP) meshwork. Here, we developed a simple dilution protocol to increase the urinary EV yield by disrupting the interaction between THP filaments and EVs with the help of alkaline pH and lowered ionic concentration. The integrity of the EVs and THP was assessed by electron microscopy. The effect of the protocol on the EV yield was quantified against an undiluted control by western blotting of four EV markers, nanoparticle tracking analysis and measuring of the RNA/miRNA concentration of the EV samples. The average EV yield from the dilution protocol was 2–7 fold the yield from the undiluted control i.e. increased by 130–624% as measured by western blotting and NTA. The yield increased most from samples with a high THP to EV ratio. The morphology and size range of the EVs were unaltered by the protocol. However, RNA/miRNA yields were the same as from the undiluted control and THP filaments could still be detected in EV samples. The dilution protocol, that we named KeepEX, provides a simple and efficient way to prevent loss of EVs thus increasing their yield from urine. Since KeepEX does not require individual adjustment of sample pH nor extra centrifugation steps, it could be used on its own or in combination with other EV purification protocols to improve EV isolation particularly from small urine volumes. [ABSTRACT FROM AUTHOR]

Ageing is a complex process characterised by a systemic and progressive deterioration of biological functions. As ageing is associated with an increased prevalence of age-related chronic disorders, understanding its underlying molecular mechanisms can pave the way for therapeutic interventions and managing complications. Animal models such as mice are commonly used in ageing research as they have a shorter lifespan in comparison to humans and are also genetically close to humans. To assess the translatability of mouse ageing to human ageing, the urinary proteome in 89 wild-type (C57BL/6) mice aged between 8–96 weeks was investigated using capillary electrophoresis coupled to mass spectrometry (CE-MS). Using age as a continuous variable, 295 peptides significantly correlated with age in mice were identified. To investigate the relevance of using mouse models in human ageing studies, a comparison was performed with a previous correlation analysis using 1227 healthy subjects. In mice and humans, a decrease in urinary excretion of fibrillar collagens and an increase of uromodulin fragments was observed with advanced age. Of the 295 peptides correlating with age, 49 had a strong homology to the respective human age-related peptides. These ortholog peptides including several collagen (N = 44) and uromodulin (N = 5) fragments were used to generate an ageing classifier that was able to discriminate the age among both wild-type mice and healthy subjects. Additionally, the ageing classifier depicted that telomerase knock-out mice were older than their chronological age. Hence, with a focus on ortholog urinary peptides mouse ageing can be translated to human ageing. [ABSTRACT FROM AUTHOR]

Background Uromodulin-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 . Methods We 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. Results Whole 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. Conclusions The 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. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the changes of urinary microvesicle-bound uromodulin and total urinary uromodulin levels in human urine and the correlations with the severity of diabetic kidney disease (DKD). 31 healthy subjects without diabetes and 100 patients with type 2 diabetes mellitus (T2DM) were included in this study. The patients with T2DM were divided into three groups based on the urinary albumin/creatinine ratio (UACR): normoalbuminuria group (DM, n=46); microalbuminuria group (DN1, n=32); and macroalbuminuria group (DN2, n=22). We use a specific monoclonal antibody AD-1 to capture the urinary microvesicles. Urinary microvesicle-bound uromodulin and total urinary uromodulin levels were determined by enzyme-linked immunosorbent assay (ELISA). Our results showed that the levels of urinary microvesicle-bound uromodulin in DN1 and DN2 groups were significantly higher than those in control group and DM group (P<0.01). Multiple stepwise linear regression analysis showed that UACR was independent determinant for urinary microvesicle-bound uromodulin (P<0.05) but not for total urinary uromodulin. These findings suggest that the levels of urinary microvesicle-bound uromodulin are associated with the severity of DKD. The uromodulin in urinary microvesicles may be a specific marker of DKD and potentially may be used to predict the onset and/or monitor the progression of DKD. [ABSTRACT FROM AUTHOR]

Prostate cancer (PCa) is one of the most prevalent types of cancer in men worldwide; however, the main diagnostic tests available for PCa have limitations and a biopsy is required for histopathological confirmation of the disease. Prostate-specific antigen (PSA) is the main biomarker used for the early detection of PCa, but an elevated serum concentration is not cancer-specific. Therefore, there is a need for the discovery of new non-invasive biomarkers that can accurately diagnose PCa. The present study used trichloroacetic acid-induced protein precipitation and liquid chromatography-mass spectrometry to profile endogenous peptides in urine samples from patients with PCa (n=33), benign prostatic hyperplasia (n=25) and healthy individuals (n=28). Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of urinary peptides. In addition, Proteasix tool was used for in silico prediction of protease cleavage sites. Five urinary peptides derived from uromodulin were revealed to be significantly altered between the study groups, all of which were less abundant in the PCa group. This peptide panel showed a high potential to discriminate between the study groups, resulting in area under the curve (AUC) values between 0.788 and 0.951. In addition, urinary peptides outperformed PSA in discriminating between malignant and benign prostate conditions (AUC=0.847), showing high sensitivity (81.82%) and specificity (88%). From in silico analyses, the proteases HTRA2, KLK3, KLK4, KLK14 and MMP25 were identified as potentially involved in the degradation of uromodulin peptides in the urine of patients with PCa. In conclusion, the present study allowed the identification of urinary peptides with potential for use as non-invasive biomarkers in PCa diagnosis. [ABSTRACT FROM AUTHOR]

Although changes in dietary sodium intake alter blood pressure (BP) in salt-sensitive individuals, pathophysiological mechanisms are still unknown. It has been reported that uromodulin is involved in sodium tubular transport, and genome-wide association studies pointed to UMOD gene as one of the most important gene candidates for arterial hypertension. Our aim was to analyze urinary uromodulin, salt intake and BP in 326 young middle-aged subjects (mean age 36±8 years, 49.4% male). In a subgroup of 175 individuals, ambulatory blood pressure monitoring and echocardiogram were performed. Uromodulin was determined by ELISA. According to the JNC-7 criteria, subjects were classified as optimal BP (n=103, men 72%), prehypertension (PHT) (n=143, men 43%) and hypertension (HT) (n= 80, men 38%). There were no differences in age, salt intake, estimated glomerular filtration rate, sodium excretion and uromodulin among BP groups. However, in PHT subjects, uromodulin was positively associated with fractional sodium excretion and negatively with 24-h sodium excretion and diastolic BP dip. These findings point to the effect of uromodulin on sodium reabsorption along the nephron and consequently circadian BP alteration in prehypertensives., (Sestre Milosrdnice University Hospital.)