Urine cystatin-C Research Articles

Urinary cystatin-C and urinary NGAL associated with sepsis predicts longer hospital stay in premature newborns.

Aim: To evaluate the urinary biomarkers related to sepsis in preterm newborns (NBs) and to investigate the predictive capacity of these biomarkers for a longer hospital stay.Methods: Serum and urine were collected from 27 healthy NBs, 24 NBs with neonatal infection without sepsis and 11 NBs with sepsis for the measurement of sindecan-1, lipocalin associated with urinary neutrophil gelatinase (uNGAL), urinary cystatin-C (uCysC) and urinary kidney injury molecule-1.Results: Levels of uNGAL and urinary cystatin-C were elevated in NBs with sepsis and neonatal infection, and uNGAL was significant predictor of hospital stay longer than 30days (odds ratio: 1.052; 95% CI: 1.012-1.093; p=0.01).Conclusion: uNGAL was associated with sepsis in preterm NBs and was useful to predict extended hospital stay.

Fluoride exposure and pediatric kidney health in dry, wet and intermediate climatic zone communities in Sri Lanka: Implications from urinary Cystatin-C, and albumin-creatinine ratio

BackgroundHigh fluoride exposure is increasingly discussed attributing to kidney injury as a causative factor. Depending on geochemistry, differential fluoride levels in drinking water are identified in different regions in Sri Lanka. However, the levels of fluoride exposure, and associations with kidney health has not been adequately studied in Sri Lanka, particularly in pediatric communities. Hence, the present study aimed to assess fluoride exposure in selected pediatric communities in the dry, wet and intermediate climatic zones in Sri Lanka, along with an assessment of renal health using urinary Cystatin-C (uCys-C), and albumin-creatinine ratio (uACR). MethodsWe conducted a cross-sectional study with school students in selected education zones representing dry (N = 331), wet (N = 152), and intermediate (N = 292) climatic zones in Sri Lanka. Fluoride contents in urine and drinking water were assessed as measures of fluoride exposure. ResultsThe median (interquartile distance) urinary fluoride levels of participants in the dry, wet and intermediate zones were 1.63(1.04–2.85), 1.29(0.85–2.21), and 1.07(0.61–1.98) mg/gCr while the fluoride contents of drinking water samples were 1.76(1.36–2.30), 0.25(0.18–0.37), and 0.43(0.26–0.63) ppm respectively with significant differences among the three groups. Median uCys-C level (ng/mgCr) of the participants in intermediate zone [30.26(8.49–71.44)] was significantly low (p < 0.05) compared to that of the participants in dry zone [56.19(7.08–211.8)], and wet zone [66.29(30.43–125.20)]. The incidences of elevated uCys-C levels above reference intervals in participants of dry zone (47.7%), and wet zone (50.0%) were significantly high (p < 0.001) compared to the intermediate zone (26.4%). ConclusionRelatively high fluoride exposure is likely in dry and wet zone communities compared to the intermediate zone along with significantly higher incidence of uCys-C levels above reference intervals in study groups with higher fluoride exposure. However, to conclude a clear link between fluoride exposure and kidney health we need in-depth studies.

Detection of urinary cystatin-c in IUGR neonates by immunoblot SDS-PAGE.

it is known that intrauterine growth retardation (IUGR) represents a risk factor for the deterioration of renal function as it can adversely impact on the number of nephrons developed in the kidney during nephrogenesis. An interesting molecule is the Cystatin-C (cyst-C): it is considered to have the potency to detect both glomerular and proximal renal injury. Recently, using a quantitative EIA cyst-C detection kit, we found increased levels of cyst-C in the urine of neonates with IUGR. Since cyst-C molecules can be present in both monomer and/or polymer forms, the purpose of this study is to investigate in which forms this molecule is present in the urine of IUGR neonates by Immunoblot SDS-PAGE in order to verify if the presence or absence of a particular type of cyst-C conformation can give more information about the renal functioning. urine samples were collected from 64 neonates with IUGR, and 86 healthy controls defined as appropriate for gestational age (AGA). Urinary cyst-C was investigated by the Immunoblot SDS-PAGE. in all urine samples, SDS-PAGE analysis showed a reactivity of the IgG anti cyst-C with a complex of about 70kDa. The monomer form at 13KDa appeared in 78% of IUGR neonates and in 12% of AGA neonates. this study revealed the presence of monomer cyst-C in the urine of IUGR neonates, and suggests an insufficient and/or non-compensatory reabsorption by tubular cells. Monomeric cyst-C can be considered an early biochemical marker to identify and to select IUGR neonates who need to be monitored for risk of renal injury.

MO1027: Kidney Tubular Damage Associated with Early Sepsis and Longer Hospital Stay in Newborns with Neonatal Infection

Abstract BACKGROUND AND AIMS The aim of the study was to evaluate the early association of urinary cystatin-C (uCysC) (proximal tubular injury biomarkers) with sepsis and longer hospital stay in premature newborns (NBs) with neonatal infection. METHOD This is a prospective study with NBs from Neonatal Intensive Care Unit (nUTI), between August 2019 and September 2020. Three groups were constructed: healthy NBs, NBs with neonatal infection without sepsis and NBs with sepsis. Premature newborns with kidney disease, renal malformation, insufficient data in the medical record, or samples with scarce volume were excluded. Urine samples were collected for biomarkers measurements. Urinary cystatin-C was quantified in the urine and expressed with or without ratio by urinary creatinine to investigate the urinary concentration bias. RESULTS In total, 62 NBs were included: 27 healthy, 24 with neonatal infection without sepsis and 11 with sepsis. No acute kidney injury (AKI) was found in NBs and 22 (63%) had longer hospital stay (˃ 30 days). Higher levels of urinary cystatin-C, both adjusted for urinary creatinine, were elevated in NBs's sepsis group. Moreover, in NBs with a longer hospital stay, there was an elevated level of urinary cystatin-C, which was capable to predict the need for ˃ 30 days of hospital stay (AUC-ROC = 0.783, P = .01). CONCLUSION Our study demonstrated that kidney tubular damage biomarker, such as uCysC, was associated with early sepsis in premature NBs and was useful to prognosis evaluation.

METTL3 enhances NSD2 mRNA stability to reduce renal impairment and interstitial fibrosis in mice with diabetic nephropathy

BackgroundNuclear receptor-binding SET domain protein 2 (NSD2) is a histone methyltransferase that has been demonstrated to regulate insulin secretion and glucose concentration. This study focused on the role of NSD2 in the renal impairment during diabetic nephropathy (DN).MethodsSerum NSD2 level in patients with DN was examined, and its correlations with the renal impairment-related indicators were examined. A murine model of DN was established, and mouse mesangial cells (SV40-MES-13) were treated with high-glucose (HG) to mimic a DN-like condition in vitro. Overexpression of NSD2 was introduced into mice or cells for in vivo and in vitro studies. The m6A level in HG-treated SV40-MES-13 cells was analyzed. METTL3 expression and its correlation with NSD2 were determined.ResultsNSD2 was poorly expressed in the serum of patients with DN and was negatively correlated with the levels of fasting blood sugar (FBG), serum creatinine (SCr), serum cystatin C (S-Cys-C), the 24-h urine protein (24-h U-protein) and the urine cystatin C (U-Cys-C). NSD2 overexpression reduced the kidney weight and reduced renal impairment in mice. It also suppressed interstitial fibrosis in mouse kidney tissues and reduced fibrosis-related markers in HG-treated SV40-MES-13 cells. HG treatment reduced the m6A level in the cells. METTL3 promoted m6A modification of NDS2 mRNA and enhanced its stability by YTHDF1. METTL3 overexpression alleviated renal impairment and fibrosis in vivo and in vitro. But the protective role was blocked upon NSD2 silencing.ConclusionThis study demonstrates that METTL3 promotes NSD2 mRNA stability by YTHDF1 to alleviate progression of DN.

Combined detection of urinary biomarkers noninvasively predicts extent of renal injury in patients with early diabetic kidney disease with kidney qi deficiency syndrome: A retrospective investigation.

Incipient diagnosis and noninvasive forecasts using urinary biomarkers are important for preventing diabetic kidney disease (DKD) progression, but they are also controversial. Previous studies have shown a potential relationship between urinary tubular biomarkers (UTBs) and traditional Chinese medicine (TCM) syndrome in patients with DKD. Thus, we further evaluated the clinical significance of combined detection of urinary biomarkers in noninvasively predicting the extent of renal damage in patients with early DKD with kidney qi deficiency syndrome, and preliminarily explored the potential biological link between UTBs and TCM syndrome in DKD. We categorized 92 patients with Type 2 diabetes mellitus into three groups as follows: 20 patients with normoalbuminuria, 50 patients with microalbuminuria, and 22 patients with macroalbuminuria. We found that, in all groups, 24 hr urinary albumin (24hUAlb) and urinary albumin-to-creatinine ratio (UACR) showed stepwise and significant increases. Urinary cystatin C (UCysC), urinary N-acetyl-β-d-glucosaminidase (UNAG), and urinary retinol-binding protein (URBP) synchronously increased gradually, consistent with the degree of albuminuria in all groups. Moreover, 24hUAlb and UACR were positively correlated with UCysC, UNAG, and URBP, respectively. In 72 patients with Type 2 DKD with albuminuria, a positive correlation was observed between UNAG and URBP, UCysC was also positively correlated with UNAG and URBP, respectively. Additionally, TCM syndrome distributional characteristics in all patients were consistent with clinical manifestations of kidney qi deficiency syndrome. Therefore, the combined detection of UCysC, UNAG, URBP, and UAlb may be used as a practical clinical technique to noninvasively forecast the extent of renal injury in patients with early Type 2 DKD with kidney qi deficiency syndrome. UTBs may be one of the biological bases of the specific TCM syndromes in DKD.

1262-PUB: Observational Study to Evaluate the Presence of Tubulopathy and Glomerulopathy in Indian T2DM Patients and to Correlate Their Presence with Established Risk Factors for Nephropathy

Objective: Urinary cystatin C (UCC) is an emerging marker of DN. UCC has recently been suggested as an alternative marker in eGFR due to its favorable properties. This study was conducted to evaluate the presence of glomerulopathy and tubulopathy in patients with type 2 diabetes mellitus (T2DM) and to correlate them with established risk factors for nephropathy. We aimed at evaluating the level of UCC as a marker of tubulointerstitial damage in patients with T2DM in relation to the level of albuminuria and other parameters. Methods: Sixty eight patients with T2DM (mean age, 47.44 ± 10.40 years) age- and sex-matched subjects were evaluated for UCC, serum creatinine (SCr), and urinary albumin-creatinine ratio (UACR) along with other parameters. Results: Of the 68 patients enrolled in the study, 49 were male (72%) and 19 were female (28%). The mean duration of diabetes was 7.21 ± 4.03 years, mean HbA1c was 9.1 ± 1.3%, and mean body mass index (BMI) was 23.21 ± 3.11 kg/m2. Microalbuminuria was found in 17 (25%) cases and macroalbuminuria was found in 8 (11.8%) cases. The mean UACR of the study group was 113.42 ± 252.31 mg/g creatinine and mean UCC was 741.26 ± 1523.46 ng/ml. There was a statistically significant association between rising albumin excretion and BMI, duration of diabetes, SCr, UCC, and SBP and DBP. A significant negative correlation between eGFR and age of the patient and SCr and significant positive correlation between eGFR and BMI was noted. However, a negative correlation between eGFR and UCC failed to achieve statistical significance. Conclusion: We thus conclude that UCC may be one of the early biomarkers of DN. the use of UCC measurement for early evaluation of renal involvement and may help initiation of timely treatment and prevent/delay renal complications of diabetes. Disclosure P. Hans: None. M. Kumar: None.

Cystatin C, Neutrophil Gelatinase-associated Lipocalin, and Lysozyme C: Urinary Biomarkers for Detection of Early Kidney Dysfunction in Children With Urolithiasis

OBJECTIVETo screen for the presence of biomarkers involved in tubular injury and kidney damage in children with urolithiasis (RS), and to validate these proteins by ELISA. METHODSProspective-controlled pilot study of children with urolithiasis and their age- and gender-matched controls (HC). Initial screening test was done by quantitative proteomic comparison of pooled urine from RS versus HC, using liquid chromatography-mass spectrometry. Proteins of interest were selected using the following criteria: (1) ≥5 spectral counts; (2) ≥2-fold difference in spectral counts; and (3) ≤.05 P value for the Fisher's Exact Test. Validation was performed by ELISA testing. Statistical analysis was performed by Student t-test and Mann-Whitney U test. RESULTSProteomic analysis identified 3 proteins of interest, Cystatin C (CYTC), neutrophil gelatinase-associated lipocalin (NGAL) and lysozyme C that were significantly over-represented in RS group versus HC. ELISA analysis revealed significantly increased urinary levels of CYTC and NGAL, and nearly significantly increased urinary levels of lysozyme C in RS group (N = 24) compared to controls (N = 13). Subgroup analysis showed significantly higher urinary levels of CYTC in both hypercalciuria (N = 14) and hypocitraturia (N = 10) versus HC (P <.05). CONCLUSIONChildren with urolithiasis showed significant increase in urinary CYTC and NGAL irrespective of their normal serum creatinine. These biomarkers indicate tubular injury and early kidney damage and represent valid tools for early screening when traditional tests are normal.

P0745URINE TIMP-2 AND IGFBP-7- NEW BIOMARKERS OF KIDNEY INJURY IN MULTIPLE MYELOMA PATIENTS

Abstract Background and Aims Urine tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) seem to be novel kidney injury related biomarkers, especially in tubular cells damage. Free light chains (FLCs) are associated with renal failure in multiple myeloma (MM) and appear to have a prognostic value and indicate stages in MM. The aim of the study was to investigate the correlation between new biomarkers and acclaimed parameters of renal failure and markers of MM stages and prognosis. Method The study included 124 patients with MM in the mean age of 66 +/- 10 years, with median time from MM diagnosis of 30 (lower; upper quartile 14; 63) months. There were 7(6%) patients with smoldering MM, 80(65%) with ISS stage 1, 22 (18%)with stage 2 and 15 (12%) with stage 3 MM. Mean eGFR was 71 +/- 25 ml/min/1.73 m2 and 30 (24%) patients had eGFR &amp;lt;60 ml/min/1.73 m2. The examined parameters included creatinine, urine NGAL, urine and serum cystatin-C, urine and serum FLC kappa and lambda, serum monoclonal protein, IGFBP-7 and TIMP-2 in serum and urine, WBC count, IL-6, NT-proBNP, serum albumin and β2-microglobulin. IGFBP-7 and TIMP-2 in serum were measured in a subgroup of 73 patients, including 26 (36%) with eGFR &amp;lt;60 ml/min/1.73 m2. The association between between these parameters were determined by multivariate stepwise regression analysis. The p-value &amp;lt;0.05 was considered statistically significant. Results Except for urine cystatin C and urine TIMP-2, all the studied markers were higher among patients with eGFR &amp;lt;60 ml/min/1.73m2: urine NGAL: 23.3 (9.2; 68.4) vs. 7.8 (3.9; 16.8) ng/ml; p&amp;lt;0.001; urine IGFBP-7: ; serum IGFBP-7: 86.2 (29.3; 125.0) vs. 33.7 (13.2; 61.5) ng/ml; p=0.003; and serum TIMP-2: 628 (498; 663) vs. 431 (360; 614) ng/ml; p=0.011, respectively. Serum and urine IGFBP-7 and urine NGAL were also higher among patients with ISS grade 3 comparing to the rest of the group (p=0.008, p&amp;lt;0.001 and p=0.033, respectively). Patients with smoldering myeloma did not differ from those with symptomatic disease. No differences in studied markers were observed between patients with newly diagnosed MM in comparison to those who had been treated with one or more schemes. Only urinary IGFBP-7 differed between patients who were on treatment at the time of samples’ collection (median ng/ml) in comparison to untreated (median ng/ml; p=0.009). No differences in TIMP-2 and IGFBP-7 levels in patients divided according to MM state were observed (remission vs stable vs progressive disease). In whole studied group, urinary markers of tubular injury were interrelated: cystatin C correlated positively with NGAL monomer (R=0.22; p=0.016), IGFBP-7 (R=0.26; p=0.004) and TIMP-2 (R=0.22; p=0.016), NGAL correlated positively with IGFBP-7 (R=0.39; p&amp;lt;0.001) and TIMP-2 (R=0.25; p=0.005), and IGFBP-7 correlated positively with TIMP-2 (R=0.31; p&amp;lt;0.001). In multiple linear regression, the negative correlation between urinary IGFBP-7 and eGFR was independent of other studied urinary markers of tubular injury. However, after adjustment for confounders (age, smoldering versus symptomatic MM, ISS, LDH, remission versus stable or progressive disease, and the concentrations of involved urine light chains), only urinary NGAL was independently associated with eGFR. Conclusion Urine TIMP-2 and IGFBP-7 may be useful in investigating tubular renal damage in patients with chronic kidney injury among patients with MM. This can lead to noninvasive biomarker-targeted diagnostic interventions and contribute to early beginning of treatment that may improve life expectancy quality of life in MM.

Urinary Cystatin-C, a marker to assess and monitor neonatal kidney maturation and function: validation in twins.

Nephrogenesis is a complex process of nephron formation and maturation that can be compromised by preterm delivery and intrauterine growth restriction. This study aimed to evaluate and compare urinary Cys-C levels with renal volume in a cohort of preterm and term twins, adequate for gestational age or intrauterine growth restricted, to investigate their values in different conditions of nephrogenesis. The study was performed on twins at 30-40 days of postnatal corrected age: renal volumes were measured by 3D ultrasound technology and urine samples were analyzed for Cystatin-C. A follow-up was performed by Cystatin-C. Renal volumes in preterm and intrauterine growth-restricted twins showed values significantly lower than those observed in term twins and were inversely correlated to urinary Cystatin-C levels. During the follow-up, intrauterine growth-restricted twins showed amplified levels of urinary Cystatin-C; in contrast, invariable or decreased levels were observed in adequate for gestational age twins. Urinary Cystatin-C, evaluated when intrauterine/extrauterine nephrogenesis could be considered completed, concurrently with renal volume assessment can improve the identification of neonates with initial kidney impairment. Its potential value as a useful marker in monitoring physiological/pathological renal conditions could be considered, mainly for neonates at elevated risk of developing long-term renal diseases. Urinary Cys-C levels are inversely correlated to renal volumes and reflect nephrogenesis conditions. No data in literature are reported regarding: (a) the concurrent assessment of renal volumes and urinary levels of Cystatin-C in preterm and term twins with different conditions of gestational life, i.e., AGA and IUGR and (b) the follow-up of IUGR and preterm neonates using the urinary Cys-C determination. The variations of urinary Cys-C levels, observed in the follow-up of preterm and/or IUGR neonates, support the usefulness of monitoring those neonates with altered nephrogenesis, who are later at risk for renal impairment and for long-term renal diseases.

MON-290 THE ASSOCIATION OF URINARY BIOMARKERS FORECASTS RENAL INJURIOUS EXTENT IN THE INCIPIENT TYPE 2 DIABETIC KIDNEY DISEASE PATIENTS

Diabetic kidney disease (DKD) becomes a common health problem worldwide as one of the major microvascular complications of diabetes mellitus (DM). The incipient diagnosis and the noninvasive detections in clinic are thereby of major importance of preventing the progression from DKD to end-stage renal disease. Recently the increasing evidences have demonstrated the impaired absorption of the filtered proteins by renal tubular epithelium might also play the important roles in the incipient DKD patients. Despite this, the clinical significances of urinary biomarkers in predicting renal injurious extent of DKD are controversial. Therefore, this study aimed to evaluate ulteriorly the clinical significances of association of urinary biomarkers in predicting renal damaged extent of the type 2 DKD patients at the early stage in a signal-center. The study was performed on the 92 type 2 DM patients with the different levels of urinary albumin (UAlb) and certain range of serum creatinine (Scr). According to urinary albumin-to-creatinine ratio (UACR), all patients were categorized into 3 groups, a normo-albuminuria (< 30 mg/g creatinine) group, a micro-albuminuria (30-300 mg/g creatinine) group and a macro-albuminuria (> 300 mg/g ceatinine) group. In addition to UAlb and UACR, Scr, estimated glomerular filtration rate (eGFR) and urinary tubular biomarkers including urinary cystatin C (UCysC), urinary N-acety1-β-D-glucosaminidase (UNAG) and urinary retinal binding protein (URBP) were tested, respectively. In all patients, 24hUAlb and UACR showed the stepwise increases and the significant differences in normo-albuminuria, micro-albuminuria and macro-albuminuria groups. Additionally, UCysC, UNAG and URBP synchronously revealed the gradual increases along with albuminuria in the 3 groups, and there was a significant difference between normo-albuminuria and micro-albuminuria groups, as well as that between micro-albuminuria and macro-albuminuria groups. Moreover, 24hUAlb and UACR were positively correlated with UCysC, UNAG and URBP. In the 72 type 2 DKD patients with micro-albuminuria and macro-albuminuria, there was a positive correlation between UNAG and URBP, and that UCysC was positively correlated with UNAG and URBP. In the incipient type 2 DKD patients, increased UCysC, UNAG and URBP are independently associated with UAlb, and these urinary tubular biomarkers cooperated with UAlb may be widely used as the practical targets in clinic in predicting renal damaged extent.

Novel automated immune turbidimetric assay for routine urinary cystatin-C determinations.

There is no commercially available urinary cystatin-C (u-CYSC) test in the market. Therefore, we optimized and validated an automated immune turbidimetric test for u-CYSC measurements and investigated u-CYSC concentrations in acute and chronic diseases which might lead to renal tubular disorders. A particle-enhanced immune turbidimetric assay was adapted and validated on a Cobas 8000/c502 analyzer. Urine samples of different patient groups were also analyzed. Our method showed excellent analytical performance. U-CYSC/u-creatinine (u-CREAT) was higher in sepsis-related acute kidney injury group (p<0.001) compared with controls and to patients with chronic hypertension and Type 2 diabetes. We validated a fast, sensitive, fully automated u-CYSC assay which is ideal for routine use and might be a potential complementary laboratory test to evaluate renal tubular function.

Assessment of Glomerular and Tubular Function in the Evaluation of Diabetic Nephropathy: A Cross-sectional Study.

Background:Diabetic nephropathy (DN) occurs in 20%–40% of patients with diabetes, and it is characterized by proteinuria and progressive loss of renal functions ultimately leading to end-stage renal disease. Classically, albuminuria is regarded as a consequence of diabetes-induced glomerular damage. It is now being appreciated that the renal tubulointerstitium also plays a role in the development of DN.[1] Urinary cystatin C (UCC) is an emerging marker of DN. It is totally catabolized by proximal tubular cells and is not normally present in the urine. However, in the presence of tubulopathy, it is excreted in urine, and serum levels also are elevated due to lack of catabolism.Materials and Methods:The present study was conducted to evaluate the presence of glomerulopathy and tubulopathy in patients with type 2 diabetes mellitus (T2DM) and to correlate them with established risk factors for nephropathy. We aimed at evaluating the level of UCC as a marker of tubulointerstitial damage in patients with T2DM in relation to the level of albuminuria and other parameters. Seventy-two patients with T2DM (mean age, 47.44 ± 10.40 years) and 45 healthy age- and sex-matched subjects were evaluated for UCC, serum creatinine, and urinary albumin-creatinine ratio (UACR) along with other parameters.Results:Of the 72 patients included in the study, microalbuminuria was found in 26% and macroalbuminuria in 10% of cases. UCC was significantly higher in micro- and macro-albuminuric groups in comparison with normoalbuminuric patients and correlated positively with UACR. Among the 46 patients with normoalbuminuria, 11 had elevated UCC levels indicating early tubular dysfunction.Conclusions:This finding may support the hypothesis of a “tubular phase” of diabetic kidney disease preceding overt DN, and hence, the use of UCC measurement for early evaluation of renal involvement.

Combining Novel Renal Injury Markers with Delta Serum Creatinine Early after Cardiac Surgery and Risk-Stratification for Serious Adverse Outcomes: An Exploratory Analysis

To evaluate the prognostic utility of multiple novel urinary biomarkers of renal injury when used alone, in pair-wise combination with an early delta serum creatinine (ΔSCr) term, and combined as a broad biomarker panel for the prediction of serious adverse outcomes that may reflect AKI in patients undergoing cardiac surgery. Post-hoc analysis of prospective observational study. Academic medical center. 603 adults undergoing cardiac surgery. None. Urinary cystatin-c, kidney injury molecule-1, chemokine (C-C motif) ligand 2 and interleukin-18 were measured at baseline and <1 hour, 3 hours and 18-24 hours after separation from cardiopulmonary bypass (CPB). ΔSCr-initial was defined as the difference in SCr from baseline to first postoperative measure. The primary outcome of hospital mortality or renal replacement therapy occurred in 25 patients. Concordant elevation of any urinary biomarker measured 3 hours after CPB together with ΔSCr-initial ≥0 mg.dL-1 provided excellent early risk stratification for the primary outcome (OR ≥15.1, 95% CI 4.1-55.4). Combining four urinary biomarkers together with ΔSCr-initial and neutrophil gelatinase-associated lipocalin, previously reported from the same cohort, to provide a 6-point AKI risk score enabled early identification of patients reaching the primary outcome (ROCAUC 0.86, 95% CI 0.79-0.92) with potentially useful sensitivity and specificity at varied cut-points. Combining novel urinary biomarkers of renal injury with a creatinine-based metric soon after cardiac surgery provided excellent prognostic utility for serious adverse outcomes. Future studies are required to confirm these findings and determine optimal biomarker combinations for cost-effective risk stratification.

Renal function and novel urinary biomarkers in infants with neonatal encephalopathy.

Perinatal asphyxia is associated with multi-organ injury including acute kidney injury (AKI). New urinary biomarkers may detect more subtle renal injury. Urinary biomarkers (albumin, beta-2 microglobulin, cystatin-C, epidermal growth factor, neutrophil gelatinase-associated lipocalin, osteopontin, uromodulin) were serially measured from days 1 to 7 in term infants with perinatal asphyxia and controls and compared to 'Kidney Disease Improving Global Outcome' scoring of renal injury and to encephalopathy grade. A total of 255 urine samples were taken from infants exposed to perinatal asphyxia (n=82) and term controls (n=10). Thirty-nine infants underwent therapeutic hypothermia, four died and 30 infants had acute kidney injury. Infants with acute kidney injury had significantly higher levels of urinary albumin (day 2), cystatin-C (days 1, 2, 3 and 7), neutrophil gelatinase-associated lipocalin (days 2, 3 and 7) and osteopontin (days 2, 3 and 7) and lower epidermal growth factor and uromodulin (day 1) compared to those without AKI. Day 2 cystatin-C predicted AKI with an area under receiver operating characteristic curve of 0.89, p<0.001, cut-off 9.8×104 pg/mL. NE grade II/III infants had significantly elevated levels of urinary cystatin-C, neutrophil gelatinase-associated lipocalin and decreased EGF compared to grade 0/I infants. Asphyxiated infants who develop acute kidney injury have significantly altered urinary biomarkers postnatally. Validation of neonatal AKI urinary biomarkers in a large prospective study is required. Long-term follow-up of infants post-asphyxial insult for chronic renal injury is advised.

Increased Urinary Cystatin-C Levels Correlate with Reduced Renal Volumes in Neonates with Intrauterine Growth Restriction

Background: Exposure to intrauterine growth retardation (IUGR) can have a negative impact on nephrogenesis resulting in limited fetal kidney development and supporting the hypothesis that IUGR represents a risk for renal function and long-term renal disease. Cystatin-C (Cys-C), a strong inhibitor of cysteine proteinases, is freely filtered by the kidney glomerulus and is reabsorbed by the tubules, where it is almost totally catabolized; what remains is subsequently eliminated in urine. In tubular diseases and in hyperfiltration conditions, it seems reasonable to postulate that Cys-C degradation would decrease, and consequently an increase in its urinary elimination would be observed. Objectives: The aim of this study was to investigate the urinary excretion of Cys-C simultaneously with the assessment of renal volumes in adequate for gestational age (AGA) and IUGR neonates in order to identify its clinical value in IUGR. Methods: Urinary Cys-C levels were measured using the enzyme immunoassay DetectX® Human Cystatin C kit in IUGR and AGA neonates. Whole renal and renal cortex volumes were assessed with ultrasounds (Vocal II; Software, GE). Results: Urinary Cys-C levels in IUGR were significantly higher than those found in AGA and were negatively correlated to reduced whole renal and renal cortex volumes. Conclusions: The increased levels of Cys-C in the urine of neonates with IUGR were significantly associated with reduced renal/renal cortex volumes, suggesting that Cys-C could be taken as a surrogate of nephron mass. It also could be used as an early biochemical marker to identify IUGR neonates at high risk of developing long-term renal disease and to select patients for monitoring during childhood.

Validation of potential candidate biomarkers of drug-induced nephrotoxicity and allodynia in medication-overuse headache.

BackgroundMedication-overuse headache (MOH) is a chronic disorder that results from the overuse of analgesics drugs, triptans or other acute headache compounds. Although the exact mechanisms underlying MOH remain still unknown, several studies suggest that it may be associated with development of “central sensitization”, which may cause cutaneous allodynia (CA). Furthermore, the epidemiology of drug-induced disorders suggests that medication overuse could lead to nephrotoxicity. The aim of this work was to confirm and validate the results obtained from previous proteomics studies, in which we analyzed the urinary proteome of MOH patients in comparison with healthy non-abusers individuals.MethodsMOH patients were divided into groups on the basis of the drug abused: triptans, non-steroidal anti-inflammatory drugs (NSAIDs) and mixtures, (mainly containing indomethacin, paracetamol and, in some cases, caffeine). Healthy subjects, with a history of normal renal function, were used as controls. In this study, four proteins that were found differentially expressed in urine, and, on the basis of the literature review, resulted related to kidney diseases, were verified by Western Blot and Enzyme-linked Immunosorbent Assay (ELISA); Prostaglandin-H2 D-synthase (PTGDS), uromodulin (UROM), alpha-1-microglobulin (AMBP) and cystatin-C (CYSC).ResultsWestern blot analysis allowed to validate our previous proteomics data, confirming that all MOH patients groups show a significant over-excretion of urinary PTGDS, UROM, AMBP and CYSC (excluding triptans group for this latter), in comparison with controls. Moreover, the expression of PTGDS was further evaluated by ELISA. Also by this assay, a significant increase of PTGDS was observed in all MOH abusers, according to 2-DE and Western blot results.ConclusionsIn this study, we confirmed previous findings concerning urinary proteins alterations in MOH patients, identified and demonstrated the over-expression of PTGDS, UROM, AMBP, and CYSC, particularly in NSAIDs and mixtures abusers. Over-expression of these proteins have been related to renal dysfunction and probably, PTGDS, to the development of CA. The detection and confirmation of this proteins pattern represent a promising tool for a better understanding of potential nephrotoxicity induced by drugs overuse and may enhance awareness related to the MOH-associated risks, even in absence of clinical symptoms.

Early urinary angiotensinogen excretion in critically ill neonates.

Urinary angiotensinogen is considered a reliable biomarker for intrarenal renin-angiotensin system activity. The aims of this study were to assess the urinary angiotensinogen level during the first day of life and to evaluate its correlation with renal function in critically ill neonates. Urinary angiotensinogen concentration during the first 24 hours of life was measured in 98 critically ill neonates. Neonatal renal function was assessed by urinary levels of cystatin-C, albumin and α1-microglobulin and urinary electrolyte excretion. Urinary angiotensinogen level decreased with increasing gestational age and body weight in critically ill neonates (P<0.001). After adjustment for gestational age, urinary angiotensinogen level correlated with urinary fractional excretion of sodium and urinary levels of cystatin-C and α1-microglobulin. Multivariate linear regression identified a significant impact of urinary cystatin-C on urinary angiotensinogen level (P<0.001). Furthermore, urinary angiotensinogen was significantly increased in neonates with a urinary cystatin-C-to-creatinine ratio ⩾2500 ng/mg, which was the optimal cut-off value to predict acute kidney injury in our previous study. The urinary angiotensinogen level correlates with the overall maturity of renal function during the early postnatal period in critically ill neonates and an increased urinary angiotensinogen level might reflect renal injury in immature neonates.

Assessment of cell-cycle arrest biomarkers to predict early and delayed acute kidney injury.

Purpose. To assess urinary tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein 7 ([TIMP-2]·[IGFBP7]), urinary neutrophil gelatinase-associated lipocalin (NGAL), and urinary cystatin-C as acute kidney injury predictors (AKI) exploring the association of nonrenal factors with elevated biomarker levels. Methods. We studied 94 patients with urine collected within 48 hours of ICU admission and no AKI at sampling. AKI was defined by the Kidney Disease: Improving Global Outcomes criteria. Predictive performance was assessed by the area under the receiver operating characteristics (ROC) curve. Associations between biomarkers and clinical factors were assessed by multivariate linear regression. Results. Overall, 19 patients (20%) developed AKI within 48 hours. [TIMP-2]·[IGFBP7], NGAL, or cystatin-C admission levels did not differ between patients without AKI and patients developing AKI. [TIMP-2]·[IGFBP7], NGAL, and cystatin-C were poor AKI predictors (ROC areas 0.34–0.51). Diabetes was independently associated with higher [TIMP-2]·[IGFBP7] levels (P = 0.02) but AKI was not (P = 0.24). Sepsis was independently associated with higher NGAL (P < 0.001) and cystatin-C (P = 0.003) levels. Conclusions. Urinary [TIMP-2]·[IGFBP7], NGAL, and cystatin-C should be used cautiously as AKI predictors in general ICU patients since urine levels of these biomarkers are affected by factors other than AKI and their performance can be poor.

PS-108 Urinary Biomarkers May Help Predict Outcome In Neonatal Encephalopathy

Background Following a perinatal hypoxic-is chaemic insult, term infants are at risk of multi-organ injury including AKI. Infants with NE experience up-regulation of urinary cytokines which may reflect severity of brain injury. Objective To investigate the association between novel urinary biomarkers and outcome in a group of term infants with NE compared to controls. Methods Levels of urinary biomarkers [Albumin, B2M, Cystatin-C, EGF, NGAL, Osteopontin, Uromodulin] were serially measured over day 1–11 in a group of term newborns with NE and controls. These values were compared to grade of encephalopathy defined by Sarnat score. Results Ten control and 82 cases had urine samples collected (Grade 0 NE = 7, Grade I NE = 22, Grade II NE = 42, Grade III NE = 11). Thirty-nine infants underwent TH, 4 infants died. Control infants had significantly lower B2M on day 1, NGAL on day 1–2 and significantly higher urinary EGF on day 2–3 and Uromodulin on day 3, compared with cases (p-values Conclusion Infants with NE have elevated urinary biomarkers compared to controls. Abnormal grade of encephalopathy is best predicted by day 2 urinary Cystatin-C and day 3 NGAL. Urinary biomarkers may have a role in long term outcome prediction following NE.