Urinary Protein Biomarkers Research Articles

Urinary DNA-methylation and protein biomarkers identify urothelial carcinoma among other genitourinary diseases and cancer-free individuals

BackgroundFor more than 80 years, cystoscopy has been the gold standard for identification of urothelial carcinoma (UCa). Because of many factors, such as pain of the patients during this procedure or the costs involved, non-invasive detection of UCa remains a challenge. Herein, we verify our previously identified urinary biomarkers C-X-C Motif Chemokine Ligand 16 (CXCL16) and transforming growth-factor beta induced protein (TGFBI) on the protein level as well as the CpG sites ALOX5, TRPS1 and an intergenic region on Chromosome 16 on DNA methylation level in an independent cross-sectional study.MethodsWe collected N = 1119 urines from individuals coming to urological and gynecological check-ups, follow-up care or patients suspicious for UCa or already diagnosed for different urologic or gynecologic cancer entities. We performed methylation analysis of various CpG sites with DNA isolated from urine sediment and quantified the concentration of the protein markers CXCL16 and TGFBI in the corresponding urine supernatant using ELISA. We tested for patient-group differences with two-sided Wilcoxon rank sum tests and examined the performance with receiver operating characteristic curves. For verification, we analyzed the marker performance with previously set cutoff-values and marker combinations with established and experimental algorithms (with logical OR-conjunction, iterative threshold-based biomarker and score combining algorithm “PanelomiX”).ResultsEvaluation confirmed that our previously identified protein and DNA methylation biomarkers can distinguish UCa from frequent urological and gynecological cancers. CXCL16 and TGFBI discriminated UCa cases with a sensitivity of 31% and 56% and a specificity of 94% and 85%, respectively. Combining methylation markers resulted in UCa detection in men with a sensitivity of 54% and a specificity of 94%. Extending analysis by combining all methylation and protein markers (up to five markers in total) yielded a convincingly high specificity of 97% at a sensitivity of 72% for the identification of UCa patients within a heterogeneous collective of cancer-free individuals and patients suffering from urological or gynecological cancers.ConclusionCombining various biomarkers at protein and DNA level demonstrates a new option of non-invasive UCa diagnosis in urine, and thus might help to reduce the number of unnecessary cystoscopies, especially in patients without a history of UCa.

Urinary biomarkers for active Lupus Nephritis that have survived independent validation across cohorts

Most reported biomarkers for lupus nephritis (LN) have not been independently validated across cohorts. Moreover, many of the documented biomarker candidates have been reported to be elevated in LN compared to healthy controls. However, biomarkers that distinguish patients with active LN (ALN) from inactive systemic lupus erythematosus (iSLE) hold significant clinical utility. Hence, our review attempts to identify urine protein biomarkers for LN that have been independently validated across two or more cohorts and exhibit good diagnostic potential for distinguishing ALN from iSLE. PubMed and OVID were screened for studies assessing the diagnostic value of urinary biomarkers in patients with ALN compared to iSLE. Forty peer-reviewed articles were evaluated, encompassing urine biomarker data from 3,411 distinct patients. Of the 32 candidate biomarkers identified, fourteen were repeatedly reported/tested in four or more papers each, namely ALCAM, CCL2 (MCP1), CD163, HAVCR1 (KIM-1), HPGDS, ICAM-1 (CD54), ICAM-2 (CD102), IGFBP-2, LCN2, NCAM-1 (CD56), SELE (E-Selectin), SELL (L-Selectin), TNFSF12 (TWEAK), and VCAM-1, with most exhibiting C-statistics of 0.80 or more across multiple studies when discriminating patients with ALN from iSLE. The 32 reproducibly elevated biomarkers for active LN mapped to nine functional categories. The urinary proteins reported here promise to serve as a liquid biopsy for ALN. Besides representing potential candidates for diagnostic, monitoring, predictive, and prognostic biomarkers in LN, they also provide a window into potential molecular processes within the kidney that may be driving LN. Thus, ongoing advances in proteomics, which offer wider proteome coverage at increased sensitivity, are likely to further reshape our perspective of urinary biomarkers for LN.

Cellulose acetate electrophoretic separation of serum and urine proteins in Nigerian children with autism spectrum disorders

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental disorder (NDD) characterized by social communication challenges and restricted, repetitive behaviors. While genetic and environmental factors are known to contribute to ASD, the role of the immune system remains unclear. This study investigated the separation patterns of serum and urine proteins in Nigerian children with ASD compared to typically developing children and children with other NDDs.MethodsForty-seven participants aged 3–8 years were recruited, including 16 children diagnosed with ASD and 16 children with other NDDs, both according to DSM-5 criteria, along with 15 neurotypical children. Blood and urine samples were collected for protein analysis. Total protein and albumin levels were measured in both serum and urine using established methods. Protein separation in serum and urine was performed using cellulose acetate electrophoresis, followed by densitometry analysis of the electrophoretic patterns.ResultsThe results revealed no significant differences in total serum protein levels and most protein fractions between the groups. However, children with other NDDs exhibited significantly lower levels of alpha-2 globulin compared to neurotypical children. Conversely, both ASD and NDD groups showed significantly higher gamma globulin levels compared to the control group. Interestingly, spot urine protein levels were significantly higher in children with ASD compared to neurotypical children.ConclusionThe observed changes in alpha-2 and gamma globulin levels suggest potential immune system involvement in ASD and other NDDs. The higher urine protein excretion in the ASD group warrants further investigation to explore the potential of urinary protein biomarkers for ASD diagnosis.

Assessment of urine metabolite biomarkers for the detection of S. haematobium infection in pre-school aged children in a rural community in Zimbabwe

BackgroundEarly diagnosis of urogenital schistosomiasis is key to its control and elimination. The current gold standard microscopic examination techniques lack sensitivity in detecting light Schistosomiasis infections in pre-school aged children thus it is urgent to develop diagnostic tools that may be integrated into control programs. In this study, we evaluated the diagnostic performance of urine metabolite biomarkers using a chemical reagent strip in the detection of S. haematobium infection in pre-school aged children. MethodsA case-control study was conducted involving 82 pre-school aged children that were age and sex matched. Urine samples were collected for 3 consecutive days and were evaluated using urine filtration gold techniques as the gold standard method. The samples were simultaneously measured for metabolite biomarkers specifically haematuria, proteins, ketones, nitrites, glucose, bilirubin and urobilinogen using chemical reagent strips. Pearson correlation test was used to measure the relationship between S. haematobium infection and the urine metabolite biomarkers. ResultsThe diagnostic performance of urine biomarkers were correlated with the microscopic examination urine filtration technique. Haematuria (r = 0.592, p = 0.0001) and proteinuria (r = 0.448, p = 0.0001) were correlated to S. haematobium infection. Negative correlations with p > 0.05 were recorded for ketones and urobilinogen. Highest sensitivity was 65.9 % (CI, 49.4 - 79.9) for haematuria whilst protein (albumin) biomarker had a lower specificity value of 43.9 % (28.5 – 60.3). Inversely, highest sensitivity was 87.8 % (73.8 – 95.9) for proteinuria whilst haematuria had a lower sensitivity value of 82.9 % (67.9 – 92.8). The positive predictive values ranged from 57.7 % (41.6 – 72.2) to 79.4 % (65.5 - 88.7) whereas negative predictive values ranged from 70.8 % (60.8 – 79.2) to 52.0 % (48.7 – 55.3). With respect to diagnostic efficiency, haematuria had a fair diagnostic performance with an area under the curve of 0.76 followed by proteinuria with proteinuria whilst the remaining metabolites fail discriminating ability with an area under the curve of <0.5. ConclusionAlthough haematuria and protein biomarkers in urine are moderately sensitive and specific, they are important morbidity indicators of urogenital schistosomiasis in pre-school aged that may be utilised during screening in schistosomiasis control programs. We recommend comprehensive analysis of biomarkers using metabolomics techniques to identify novel urine biomarkers.

Urinary complement factor D is increased in primary malignant hypertension: a single-center, cross-sectional study

Kidney injury is one of the detrimental consequences of primary malignant hypertension (pMHTN). There is a paucity of non-invasive biomarkers to enhance diagnosis and elucidate the underlying mechanisms. This study aims to explore urine protein biomarkers for pMHTN associated renal damage. In the discovery phase, urine samples were collected from 8 pMHTN, 19 disease controls (DCs), and 5 healthy controls (HCs). In-gel digestion combined with liquid chromatography–tandem mass spectrometry (LC–MS/MS) approach was used for identification of proteins associated with pMHTN. In the validation phase, the differentially expressed proteins were validated by ELISA assay in cohort with 10 pMHTN patients, 37 DCs, and 30 HCs. Compared to DCs and HCs, a specific band between 15 and 25 kDa was found in 7 out of 8 patients with pMHTN. Further LC–MS/MS analysis revealed 5 differentially expressed proteins. ELISA validation demonstrated that urinary complement factor D (CFD) was significantly up regulated in pMHTN. By receiver operating characteristic curve analysis, urinary CFD/Cr showed moderate potential in discriminating pMHTN from DCs (the area under curve: 0.822, 95% CI 0.618–0.962). Urinary CFD may be a potential biomarker for pMHTN with its elevation indicative of the activation of the alternative complement pathway in pMHTN.

Urinary dipeptidase 1 and trefoil factor 1 are promising biomarkers for early diagnosis of colorectal cancer.

Currently utilized serum tumor markers and fecal immunochemical tests do not have sufficient diagnostic power for colorectal cancer (CRC) due to their low sensitivities. To establish non-invasive urinary protein biomarkers for early CRC diagnosis, we performed stepwise analyses employing urine samples from CRCs and healthy controls (HCs). Among 474 urine samples, 363 age- and sex-matched participants (188 HCs, 175 stage 0-III CRCs) were randomly divided into discovery (16 HCs, 16 CRCs), training (110 HCs, 110 CRCs), and validation (62 HCs, 49 CRCs) cohorts. Of the 23 urinary protein candidates comprehensively identified from mass spectrometry in the discovery cohort, urinary levels of dipeptidase 1 (uDPEP1) and Trefoil factor1 (uTFF1) were the two most significant diagnostic biomarkers for CRC in both training and validation cohorts using enzyme-linked immunosorbent assays. A urinary biomarker panel comprising uDPEP1 and uTFF1 significantly distinguished CRCs from HCs, showing area under the curves of 0.825-0.956 for stage 0-III CRC and 0.792-0.852 for stage 0/I CRC. uDPEP1 and uTFF1 also significantly distinguished colorectal adenoma (CRA) patients from HCs, with uDPEP1 and uTFF1 increasing significantly in the order of HCs, CRA patients, and CRC patients. Moreover, expression levels of DPEP1 and TFF1 were also significantly higher in the serum and tumor tissues of CRC, compared to HCs and normal tissues, respectively. This study established a promising and non-invasive urinary protein biomarker panel, which enables the early detection of CRC with high sensitivity.

Discovering urinary protein biomarkers for hepatocellular carcinoma in the population of patients with chronic hepatitis B: A single-center case-control study.

e16230 Background: Chronic hepatitis B (CHB) can result in hepatocellular carcinoma (HCC) imposing a substantial health and economic burden worldwide. Early detection of hepatitis B virus-related HCC (HBV-HCC) in CHB with potential biomarkers has emerged as an urgent and challenging task. Recent progression of urinary proteomics provides a promising method for HBV-HCC biomarker discovery. Methods: This single-center case-control study, conducted at Peking Union Medical College Hospital, enrolled 33 patients with HBV-HCC, 26 patients with CHB, 30 healthy controls, and 33 controls with other types of cancer. Urine proteomes were analyzed using liquid chromatography with tandem mass spectrometry by data-dependent acquisition or parallel reaction monitoring, respectively. Differential analysis was carried out with limma package in R software, and the origin of selected proteins was confirmed with immunohistochemistry of surgical specimens. The diagnostic performance of the biomarker panel was evaluated with area under receiver operator curves (AUROC). Results: 21 urinary proteins were significantly upregulated in HBV-HCC compared with CHB samples, playing key roles in vesicular transportation, cytoskeleton-extracellular matrix interaction, and tumor development according to enrichment analysis. Immunohistochemistry validated the differential expression of 4 urinary proteins (4UP: HNRNPM, ADGRG1, APOC1, and RALA) across cancerous and adjacent normal liver tissues. These proteins were specifically found in HBV-HCC but not in CHB, healthy control, or other cancer controls. The AUROCs of 4UP individually (0.642 for APOC1, 0.780 for HNRNPM, 0.755 for ADGRG1, 0.729 for RALA) were no worse than that of serum α-fetoprotein (AUROC = 0.751), and the 4UP panel unified via logistic regression showed an AUROC of 0.828. Conclusions: Urinary proteomics revealed HNRNPM, ADGRG1, APOC1, and RALA as biomarkers to distinguish HBV-HCC from CHB. The 4UP could be traced back to HBV-HCC tumor cells, shedding light on pathogenesis of HBV-HCC. [Table: see text]

Comprehensive Urinary Proteome Profiling Analysis Identifies Diagnosis and Relapse Surveillance Biomarkers for Bladder Cancer.

Bladder cancer (BCa) is the predominant malignancy of the urinary system. Herein, a comprehensive urine proteomic feature was initially established for the noninvasive diagnosis and recurrence monitoring of bladder cancer. 279 cases (63 primary BCa, 87 nontumor controls (NT), 73 relapsed BCa (BCR), and 56 nonrelapsed BCa (BCNR)) were collected to screen urinary protein biomarkers. 4761 and 3668 proteins were qualified and quantified by DDA and sequential window acquisition of all theoretical mass spectra (SWATH-MS) analysis in two discovery sets, respectively. Upregulated proteins were validated by multiple reaction monitoring (MRM) in two independent combined sets. Using the multi-support vector machine-recursive feature elimination (mSVM-RFE) algorithm, a model comprising 13 proteins exhibited good performance between BCa and NT with an AUC of 0.821 (95% CI: 0.675-0.967), 90.9% sensitivity (95% CI: 72.7-100%), and 73.3% specificity (95% CI: 53.3-93.3%) in the diagnosis test set. Meanwhile, an 11-marker classifier significantly distinguished BCR from BCNR with 75.0% sensitivity (95% CI: 50.0-100%), 81.8% specificity (95% CI: 54.5-100%), and an AUC of 0.784 (95% CI: 0.609-0.959) in the test cohort for relapse surveillance. Notably, six proteins (SPR, AK1, CD2AP, ADGRF1, GMPS, and C8A) of 24 markers were newly reported. This paper reveals novel urinary protein biomarkers for BCa and offers new theoretical insights into the pathogenesis of bladder cancer (data identifier PXD044896).

#1089 Urinary Protein Biomarkers for Assessing Disease Activity and Chronicity in IgA Nephropathy

Abstract Background and Objectives IgA nephropathy (IgAN) is a progressive kidney disease characterized by the mesangial deposition of galactose-deficient IgA1, leading to kidney damage and may eventually lead to end-stage kidney disease. Current treatment decisions for IgAN patients rely on the degree of proteinuria. However, this is a non-specific parameter that can be the result of inflammatory disease activity and/or chronic glomerular damage. In this study, we employed the Olink proximity extension assay to comprehensively analyze the urinary proteome of IgAN patients. Our goal was to identify biomarkers capable of distinguishing between IgAN disease activity and disease chronicity. Method Urine samples were collected from 41 IgAN patients and 41 age- and eGFR-matched controls. Patient characteristics are shown in Table 1. Using Olink Proteomics, we measured 276 proteins in urine, from the inflammation, organ damage, and cardiometabolic panels. Comparisons were made between IgAN patients and controls, as well as between those with mild (eGFR ≥ 60 ml/min/1.73 m2 and uPCR &amp;lt; 100 mg/mmol) and active IgAN (eGFR ≥ 60 ml/min/1.73 m2 and uPCR ≥ 100 mg/mmol) to identify biomarkers for disease activity. Additionally, we compared IgAN patients with eGFR ≥ 60 ml/min/1.73 m2 to those with eGFR ≤ 30 ml/min/1.73 m2 to identify biomarkers associated with disease chronicity. Mann-Whitney U tests were used for group comparisons. Correction for multiple testing was performed using the Benjamini-Hochberg procedure. Disease activity and chronicity scores were calculated by averaging the z-scores of the identified biomarkers. Results L-Selectin (SELL), leukocyte inhibitory factor (LIF), interleukin-6 (IL-6), and carbonic anhydrase 1 (CA1) were most prominently elevated in IgAN patients compared to controls (Fig. 1A). SELL and CA1 were also markedly elevated in the active versus mild IgAN patients, and were therefore selected as biomarkers of disease activity (Fig. 1B). Contactin 2 (CNTN2) and chemokine (C-C motif) ligand 25 (CCL25) were most prominently elevated in IgAN patients with eGFR ≤ 30 ml/min/1.73 m2, and were selected as biomarkers of disease chronicity (Fig. 1C). We plotted the disease activity and chronicity scores calculated from the identified biomarkers to distinguish the different IgAN disease stages (Fig. 1D). Conclusion This study identified urine biomarkers indicative of IgAN disease activity and chronicity. Calculating an activity and chronicity score using these biomarkers offers a new approach to distinguish between inflammatory disease activity and chronicity, providing an alternative to proteinuria for guiding treatment decisions in IgAN patients. Validation of these biomarkers, and the scores calculated from them, in a larger cohort of IgAN patients is currently underway.

Predicting autosomal dominant polycystic kidney disease progression: review of promising Serum and urine biomarkers.

Autosomal dominant polycystic kidney disease (ADPKD) is one of the leading causes of end-stage renal disease. In spite of the recent tremendous progress in the understanding of ADPKD pathogenesis, the molecular mechanisms of the disease remain incompletely understood. Considering emerging new targeted therapies for ADPKD, it has become crucial to disclose easily measurable and widely available biomarkers for identifying patients with future rapid disease progression. This review encompasses all the research with a shared goal of identifying promising serum or urine biomarkers for predicting ADPKD progression or response to therapy. The rate of the ADPKD progress varies significantly between patients. The phenotypic variability is only partly explained by the underlying genetic lesion diversity. Considering significant decline in kidney function in ADPKD is not usually evident until at least 50% of the parenchyma has been destroyed, conventional kidney function measures, such as glomerular filtration rate (GFR), are not suitable for monitoring disease progression in ADPKD, particularly in its early stages. Since polycystic kidney enlargement usually precedes the decline in GFR, height-adjusted total kidney volume (ht-TKV) has been accepted as an early biomarker for assessing disease severity in ADPKD patients. However, since measuring ht-TKV is time-consuming and observer-dependent, the identification of a sensitive and quickly measurable biomarker is of a great interest for everyday clinical practice. Throughout the last decade, due to development of proteomic and metabolomic techniques and the enlightenment of multiple molecular pathways involved in the ADPKD pathogenesis, a number of urine and serum protein biomarkers have been investigated in ADPKD patients, some of which seem worth of further exploring. These include copeptin, angiotensinogen, monocyte chemoattractant protein 1, kidney injury molecule-1 and urine-to-plasma urea ratio among many others. The aim of the current review is to provide an overview of all of the published evidence on potentially clinically valuable serum and urine biomarkers that could be used for predicting disease progression or response to therapy in patients with ADPKD. Hopefully, this review will encourage future longitudinal prospective clinical studies evaluating proposed biomarkers as prognostic tools to improve management and outcome of ADPKD patients in everyday clinical practice.

Urinary Protein-Biomarkers Reliably Indicate Very Early Kidney Damage in Children With Alport Syndrome Independently of Albuminuria and Inflammation

Alport syndrome (AS) is a hereditary type IV collagen disease. It starts shortly after birth, without clinical symptoms, and progresses to end-stage kidney disease early in life. The earlier therapy starts, the more effectively end-stage kidney disease can be delayed. Clearly then, to ensure preemptive therapy, early diagnosis is an essential prerequisite. To provide early diagnosis, we searched for protein biomarkers (BMs) by mass spectrometry in dogs with AS stage 0. At this very early stage, we identified 74 candidate BMs. Of these, using commercial enzyme-linked immunosorbent assays (ELISAs), we evaluated 27 in dogs and 28 in children, 50 with AS and 104 healthy controls. Most BMs from blood appeared as fractions of multiple variants of the same protein, as shown by their chromatographic distribution before mass spectrometry. Blood samples showed only minor differences because ELISAs rarely detect disease-specific variants. However, in urine , several proteins, individually or in combination, were promising indicators of very early and preclinical kidney injury. The BMs with the highest sensitivity and specificity were collagen type XIII, hyaluronan binding protein 2 (HABP2), and complement C4 binding protein (C4BP). We generated very strong candidate BMs by our approach of first examining preclinical AS in dogs and then validating these BMs in children at early stages of disease. These BMs might serve for screening purposes for AS before the onset of kidney damage and therefore allow preemptive therapy.

Identification of Potential Urinary Protein Biomarkers in Colorectal Cancer: A Pilot Study Using a Proteomic Approach

Colorectal cancer (CRC) is among the most diagnosed malignancies worldwide, and it is also the second leading cause of cancer-related deaths. Despite recent progress in screening programs, noninvasive accurate biomarkers are still needed in the CRC field. In this study, we evaluated and compared the urinary proteomic profiles of patients with colorectal adenocarcinoma and patients without cancer, aiming to identify potential biomarker proteins. Urine samples were collected from 9 patients with CRC and 9 patients with normal colonoscopy results. Mass spectrometry (label-free LC‒MS/MS) was used to characterize the proteomic profile of the groups. Ten proteins that were differentially regulated were identified between patients in the experimental group and in the control group, with statistical significance with a p value ≤ 0.05. The only protein that presented upregulation in the CRC group was beta-2-microglobulin (B2M). Subsequent studies are needed to evaluate patients through different analysis approaches to independently verify and validate these biomarker candidates in a larger cohort sample.

BTA stat®, NMP22® BladderChek®, UBC® Rapid Test, and CancerCheck® UBC® rapid VISUAL as urinary marker for bladder cancer: Final results of a German multicenter study

Introduction and objectiveBTA stat®, NMP22® BladderChek®, UBC® Rapid Test, and CancerCheck® UBC® rapid VISUAL are urinary-based rapid tests. This multicenter study is the first study comparing all available rapid tests on a large cohort of bladder cancer patients and healthy controls in one setting. MethodsIn total 732 urine samples (second morning urine) in a real-world assessment have been analyzed. We evaluated clinical samples from 464 patients with histologically confirmed urothelial tumors of the urinary bladder (17 solitary CIS, 189 low-grade, 187 high-grade nonmuscle invasive, 71 high-grade muscle invasive), 77 patients with No Evidence of Disease (NED), and from 191 healthy controls. Urine samples were analyzed by the BTA stat®, NMP22® BladderChek®, UBC® Rapid Test point-of-care (POC) system using the concile Omega 100 POC reader, and CancerCheck® UBC® rapid VISUAL. Sensitivities and specificities were calculated by contingency analyses. ResultsAll investigated urinary markers detected more pathological concentrations in urine of bladder cancer patients compared to tumor-free patients. The calculated diagnostic sensitivities for BTA stat®, NMP22® BladderChek®, UBC® Rapid Test, CancerCheck® UBC® rapid VISUAL, and cytology were 62.4%, 13.4%, 58.2%, 28.6%, 36.2% for low-grade, 83.4%, 49.5%, 84.5%, 63.1%, 71.2% for high-grade nonmuscle invasive, and 95.8%, 35.2%, 76.1%, 50.7%, 67.7% for high-grade muscle-invasive bladder cancer. The specificity was 67.9%, 95.5%, 79.4%, 94.4%, and 83.7%, respectively. The area under the curve (AUC) after receiver operating characteristics (ROC) analysis for high-grade non–muscle-invasive tumors was 0.757, 0.725, 0.819, 0.787, and 0.774, respectively. ConclusionsThe analysis of more than 700 urine samples offers an objective view on urine-based rapid diagnostics. Elevated pathological concentrations of markers in urine of bladder cancer patients were detected in all investigated tests. The highest sensitivities for high-grade non–muscle-invasive tumors were calculated for BTA stat® and UBC® Rapid Test, whereas NMP22® BladderChek®, and cytology showed the highest specificities. BTA stat® and UBC® Rapid Test have the potential to be used as a clinical valuable urinary protein biomarker for the detection of high-grade non–muscle-invasive bladder cancer patients and could be included in the management of these tumors.

Protein Biomarkers in Chronic Kidney Disease in Children-What Do We Know So Far?

Chronic kidney disease (CKD) in children is a major concern of medical care and public health as it is related to high morbidity and mortality due to progression to end-stage kidney disease (ESKD). It is essential to identify patients with a risk of developing CKD to implement therapeutic interventions. Unfortunately, conventional markers of CKD, such as serum creatinine, glomerular filtration rate (GFR) and proteinuria, have many limitations in serving as an early and specific diagnostic tool for this condition. Despite the above, they are still the most frequently utilized as we do not have better. Studies from the last decade identified multiple CKD blood and urine protein biomarkers but mostly assessed the adult population. This article outlines some recent achievements and new perspectives in finding a set of protein biomarkers that might improve our ability to prognose CKD progression in children, monitor the response to treatment, or even become a potential therapeutic target.

Evaluation of mechanistic serum and urine biomarkers for secondary osteoarthritis associated with developmental dysplasia of the hip

ObjectiveDetermine measurable differences for mechanistic urine and serum biomarkers in patients with developmental dysplasia of the hip (DDH) prior to, and following, secondary hip osteoarthritis (OA) when compared to controls. DesignUrine and serum were collected from individuals with developmental dysplasia of the hip (n = 39), prior to (Pre-OA DDH, n = 32) and following diagnosis of secondary hip OA (Post-OA DDH, n = 7), age-matched Pre-OA controls (n = 35), and age-matched Post-OA controls (n = 12). Samples were analyzed for protein biomarkers with potential for differentiation of hip status through a Mann-Whitney U test with a Benjamini-Hochberg correction. ResultsSeveral interleukin and degradation related proteins were found to be differentially expressed when comparing DDH-related hip status prior to and following diagnosis of hip OA. In addition, MCP-1 and TIMP-1 were significantly different between younger and older patients in the control cohorts. ConclusionThese results provide initial evidence for serum and urine protein biomarkers that define clinically relevant stages of symptomatic DDH and its progression to secondary hip osteoarthritis categorized by known mechanisms of disease. Level of evidenceIII.

Novel urinary protein panels for the non-invasive diagnosis of nonalcoholic fatty liver disease and fibrosis stages.

There is an unmet clinical need for non-invasive tests to diagnose nonalcoholic fatty liver disease (NAFLD) and individual fibrosis stages. We aimed to test whether urine protein panels could be used to identify NAFLD, NAFLD with fibrosis (stage F≥1), and NAFLD with significant fibrosis (stage F≥2). We collected urine samples from 100 patients with biopsy-confirmed NAFLD and 40 healthy volunteers and proteomics and bioinformatics analyses were performed in this derivation cohort. Diagnostic models were developed for detecting NAFLD (UPNAFLD model), NAFLD with fibrosis (UPfibrosis model), or NAFLD with significant fibrosis (UPsignificant fibrosis model). Subsequently, the derivation cohort was divided into training and testing sets to evaluate the efficacy of these diagnostic models. Finally, in a separate independent validation cohort of 100 patients with biopsy-confirmed NAFLD and 45 healthy controls, urinary enzyme-linked immunosorbent assay analyses were undertaken to validate the accuracy of these newly diagnostic models. The UPfibrosis model and the UPsignificant fibrosis model showed an AUROC of 0.863 (95% CI: 0.725-1.000) and 0.858 (95% CI: 0.712-1.000) in the training set; and 0.837 (95% CI: 0.711-0.963) and 0.916 (95% CI: 0.825-1.000) in the testing set, respectively. The UPNAFLD model showed excellent diagnostic performance and the area under the receiver operator characteristic curve (AUROC) exceeded 0.90 in the derivation cohort. In the independent validation cohort, the AUROC for all three of the above diagnostic models exceeded 0.80. Our newly developed models constructed from urine protein biomarkers have good accuracy for non-invasively diagnosing liver fibrosis in NAFLD.

Urinary protein biomarkers based on LC-MS/MS analysis to discriminate vascular dementia from Alzheimer's disease in Han Chinese population.

This study aimed to identify the potential urine biomarkers of vascular dementia (VD) and unravel the disease-associated mechanisms by applying Liquid chromatography tandem-mass spectrometry (LC-MS/MS). LC-MS/MS proteomic analysis was applied to urine samples from 3 groups, including 14 patients with VD, 9 patients with AD, and 21 normal controls (NC). By searching the MS data by Proteome Discoverer software, analyzing the protein abundances qualitatively and quantitatively, comparing between groups, combining bioinformatics analysis using Gene Ontology (GO) and pathway crosstalk analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG), and literature searching, the differentially expressed proteins (DEPs) of VD can be comprehensively determined at last and were further quantified by receiver operating characteristic (ROC) curve methods. The proteomic findings showed quantitative changes in patients with VD compared to patients with NC and AD groups; among 4,699 identified urine proteins, 939 and 1,147 proteins displayed quantitative changes unique to VD vs. NC and AD, respectively, including 484 overlapped common DEPs. Then, 10 unique proteins named in KEGG database (including PLOD3, SDCBP, SRC, GPRC5B, TSG101/STP22/VPS23, THY1/CD90, PLCD, CDH16, NARS/asnS, AGRN) were confirmed by a ROC curve method. Our results suggested that urine proteins enable detection of VD from AD and VC, which may provide an opportunity for intervention.

Bilirubin level is decreased in patients with allergic rhinitis

BackgroundThere are limitations in detecting methods for early diagnosis and screening of allergic rhinitis. Considering the anti-inflammatory and anti-oxidative effects of bilirubin, this study aims to explore the relationship between bilirubin and allergic rhinitis and to identify bilirubin-related candidate urinary protein biomarkers associated with allergic rhinitis. Methods63 allergic rhinitis patients (AR group) and 86 healthy controls (NC group) were enrolled. Venous blood was obtained to measure serum total IgE levels and bilirubin parameters. Patients in the AR group were then classified into the AR1 group (IgE > 125 IU/mL) and the AR2 group (IgE ≤ 125 IU/mL). After randomly selecting ten urine samples from the AR1 group, ten samples were chosen from the AR2 and the NC groups, respectively, according to age and gender matching. We employed a Tandem Mass Tag-Based liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) proteomics approach and targeted parallel-reaction monitoring(PRM) to identify and validate urinary biomarkers for allergic rhinitis. ResultsCompared with the NC group, the bilirubin levels of the AR group, AR1 group, and AR2 group were significantly lower. Although the bilirubin level of the AR1 group was lower than that of the AR2 group, the difference was not significant. Further urinary proteomics analysis found that the expression levels of proteins related to bilirubin metabolism and transportation in the AR1 and AR2 groups, including ABCC1, GSTA1, GSTO1, GSTM3, GSTM5, and BLVRB, were significantly higher than those in the NC group. By PRM-based quantification, GSTA1 and GSTO1 showed significant differences in different degrees of Allergic Rhinitis groups and healthy controls. The AUC of the combined diagnosis of GSTA1 and GSTO1 was 0.79 (95% CI 0.583–0.997, P = 0.007), and the sensitivity and specificity were 100% and 60.0%, respectively. ConclusionsBilirubin levels are associated with allergic rhinitis. Our study revealed that urine proteomics has a specific value for exploring the pathophysiological mechanism of bilirubin changes in AR patients and screening possible biomarkers.

Evaluation of Novel Urinary Biomarkers in Beagle Dogs With Amphotericin B-Induced Kidney Injury.

Next-generation urinary protein biomarkers have been qualified to enable monitoring for drug-induced kidney injury in toxicology studies conducted in rats. However, there is limited literature on the utility of these biomarkers in dogs. To add to the existing body of knowledge on the utility of the next-generation drug-induced kidney injury (DIKI) biomarkers, we evaluated the value of these biomarkers for the early detection of DIKI in Beagle dogs using a differentiated nephrotoxicant, Amphotericin B (AmpB). In dogs with AmpB-induced kidney injury, we monitored the response of urinary albumin, total protein, clusterin, kidney injury molecule 1, neutrophil gelatinase-associated lipocalin and N-acetyl-beta-D-glucosaminidase. We also measured blood urea nitrogen, serum creatinine and cystatin C. The results showed that urinary clusterin (up to ∼ 112x) was much more sensitive to AmpB-induced kidney injury relative to other biomarkers. Moreover, other than urinary clusterin and to a much lesser extent urinary albumin and total protein, none of the other biomarkers analyzed in this study were more sensitive than blood urea nitrogen and serum creatinine. The AmpB related tubular alterations were characterized by minimal to mild, multifocal necrosis, degeneration, regeneration, dilatation and mineralization. The mild nature of these histopathologic findings further attested to the sensitivity of urinary clusterin to AmpB-induced kidney injury in dogs. These results will help drug developers make informed decisions when selecting urinary biomarkers for monitoring DIKI in dogs for toxicology studies.

Association of Novel Urinary Protein Biomarkers with Persistent Albuminuria in Patients with Sickle Cell Disease

Introduction: Standard assessments for kidney disease, albuminuria and decline in estimated glomerular filtration rate (eGFR), occur well after substantial functional and structural damage have ensued. Chronic kidney disease (CKD) is common in patients with sickle cell disease (SCD). With its association with increased morbidity and mortality, identification of novel biomarkers that could predict early development of CKD offers opportunities to modify risk factors in hopes of attenuating kidney function loss and decreasing mortality risk. Methods: The participants of this exploratory study represent a subset of patients with HbSS or HbSβ0 thalassemia enrolled in a prospective cohort study to assess the natural history of kidney disease in SCD. We excluded patients with diabetic nephropathy, cancer, connective tissue disease, other glomerular diseases, known infection with hepatitis (B or C) or HIV, end-stage kidney disease on dialysis and those who had undergone bone marrow transplantation. Participants were enrolled during routine clinic visits. Urine levels of clusterin [CLU; also referred to as apolipoprotein J], retinol-binding protein 4 [RBP4], alpha-1-microglobulin [A1M], interleukin-18 [IL-18], beta-2 microglobulin [B1M], insulin-like growth factor-binding protein 7 [IGFBP7], tissue inhibitor of metalloproteinases-2 [TIMP2], angiotensinogen [AGT], podocalyxin, and cysteine-rich with EGF-like domains 2 [CRELD2] were measured using quantitative ELISA assay. All values of urine biomarkers were normalized to urine creatinine. Persistent albuminuria (PA) was defined based on presence of at least 2 of 3 spot urine albumin/creatinine ratio (ACR) values ≥30 mg/g of creatinine or a single value ≥100 mg/g. Glomerular filtration rate was estimated using the 2009 creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. Medians are presented with the interquartile range [IQR]. Associations between ACR and eGFR with each urine biomarker were assessed using linear regression. Levels of urinary biomarkers were compared using the Wilcoxon-Mann-Whitney test. Results: Thirty-seven subjects, 13 (35.2%) with PA (ACR - 147mg/g [IQR: 136.4, 223]), and 24 (64.9%) without PA (non-PA) (ACR - 12 mg/g [IQR: [6, 20]) were evaluated. Subjects with PA were older, had higher blood urea nitrogen (BUN), blood aspartate transaminase, and lower eGFR (Table 1). Urinary levels of CLU, RBP4, A1M, and AGT normalized to urine creatinine were significantly higher in subjects with PA vs. those with non-PA (Table 2). In univariate analysis, significant associations were identified between A1M and ACR (p=0.035) as well as between AGT and ACR (p<0.0001) (Table 2). In multivariable analyses, only AGT remained significantly associated with ACR (p=0.0003). Conclusion: The higher urinary levels of RBP4 and A1M, both low molecular weight proteins freely filtered in the glomerulus and reabsorbed by kidney proximal tubule cells, in subjects with PA suggests the presence of tubular injury. Higher levels of clusterin, a ubiquitously expressed glycoprotein that is rapidly upregulated upon acute kidney damage and present in de-differentiated kidney tubule cells, also indicates tubular injury in subjects with PA. Urinary AGT, the only precursor of all angiotensin peptides, is independently associated with ACR in this cohort. Higher levels of AGT indicates increased intrarenal renin-angiotensin system activity in subjects with PA. More studies are required to evaluate the association of these biomarkers with persistent albuminuria in SCD. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal