Ultrasensitive sensing urinary cystatin C via an interface-engineered graphene extended-gate field-effect transistor for non-invasive diagnosis of chronic kidney disease.

Early chronic kidney disease (CKD) has strong concealment and lacks an efficient, non-invasive, and lable-free detection platform. Cystatin C (Cys C) in urine is closely related to the progress of CKD (especially at the early stage), which is an ideal endogenous marker to evaluate the impairment of renal function. Thus, the accurate detection of urinary Cys C (u-Cys C) is great significant for early prevention and treatment and delaying the course of the disease of CKD patients. Herein, we developed an extended-gate field-effect transistor (EG-FET) sensor for ultrasensitive detection of u-Cys C, which consists of a monolithic interface-engineered graphene EG electrode array and a commercially available MOSFET. Laser-induced graphene (LIG) loaded with sputtered Au NPs in the presence of adhesive Cr (Au NPs/Cr/LIG) boosts the electrical performance of the EG electrode. Meanwhile, Au NPs also serve as linkers to immobilize papain that can selectively form protein complexes with Cys C. Supported by the synergistic effect of multilevel interface-engineered graphene, our sensor exhibits a good linear correlation within the u-Cys C concentration range of 5 ag/µL to 50 ng/µL with low detection limit of 0.05 ag/µL. Our work makes accurate, specific and rapid detection of u-Cys C feasible and promising for early screening for CKD.

Urinary cystatin C and N-acetyl-beta-D-glucosaminidase (NAG) as early biomarkers for renal disease in dogs with leishmaniosis.

Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum that can vary from a subclinical infection to a severe disease. Dogs affected with CanL present varying degrees of renal dysfunction. Unfortunately, traditional biomarkers such as urea and creatinine detect renal damage in advanced stages of the disease, so more accurate biomarkers are needed. Hence, we aimed to study how urinary cystatin C (CysC) and N-acetyl-beta-D-glucosaminidase (NAG), behave in dogs with CanL at different stages of the disease. Eighty-six CanL infected dogs were classified according to LeishVet stages: LI (16 dogs), LIIa (12 dogs), LIIb (12 dogs), LIII (16 dogs) and LIV (30 dogs); as a control, 17 healthy dogs were studied. Blood samples were collected for complete haematological and biochemistry analysis including plasma cystatin C. Urine analysis included urine specific gravity (USG), urine protein to creatinine ratio (UPC), CysC and NAG expressed as a ratio with creatinine uCysCc (µg/g) and uNAGc (IU/g). The haematological, biochemical and urinary analysis coincided with the LeishVet guidelines. The statistical study of the uCysCc ratio and the uNAGc, showed significant increase when compared against control starting from group LI (p < 0.05). Interestingly, when the cut-off values were calculated using the ROC curve, uCysCc (258.85 µg/g) and uNAGc (2.25 IU/g) 75 % of the dogs included in LI groups surpassed the threshold. Hence our study indicates that uCysCc and uNAGc, could help to detect early renal damage in CanL affected dogs.

Impaired kidney function biomarkers and risk of severe COVID-19: Analysis of population-based cohort data.

BACKGROUND: Patients with impaired kidney function were found at a high risk of COVID-19 hospitalization and mortality in many observational, cross-sectional, and hospital-based studies, but evidence from large-scale prospective cohorts has been lacking. We aimed to examine the association of kidney function-related biomarkers and their genetic predisposition with the risk of developing severe COVID-19 in population-based data. METHODS: We analyzed data from UK Biobank to examine the prospective association of abnormal kidney function biomarkers with severe COVID-19, defined by laboratory-confirmed COVID-19 hospitalizations. Using genotype data, we constructed polygenic risk scores (PRS) to represent an individual's overall genetic risk for these biomarkers. We also identified tipping points where the risk of severe COVID-19 began to increase significantly for each biomarker. RESULTS: Of the 502,506 adults, 1650 (0.32%) were identified as severe COVID-19, before August 12, 2020. High levels of cystatin C (OR: 1.3; 95% CI: 1.2-1.5; FDR = 1.5 × 10-5 ), serum creatinine (OR: 1.7; 95% CI: 1.3-2.1; p = 3.5 × 10-4 ; FDR = 3.5 × 10-4 ), microalbuminuria (OR: 1.4; 95% CI: 1.2-1.6; FDR = 4 × 10-4 ), and UACR (urinary albumin creatinine ratio; OR: 1.4; 95% CI: 1.2-1.6; p = 3.5 × 10-4 ; FDR = 3.5 × 10-4 ) were found significantly associated with severe COVID-19. Individuals with top 10% of PRS for elevated cystatin C, urate, and microalbuminuria had 28% to 43% higher risks of severe COVID-19 than individuals with bottom 30% PRS (p < 0.05). Tipping-point analyses further supported that severe COVID-19 could occur even when the values of cystatin C, urate (male), and microalbuminuria were within their normal value ranges (OR >1.1, p < 0.05). CONCLUSIONS: Findings from this study might point to new directions for clinicians and policymakers in optimizing risk-stratification among patients based on polygenic risk estimation and tipping points of kidney function markers. Our results call for further investigation to develop a better strategy to prevent severe COVID-19 outcomes among patients with genetic predisposition to impaired kidney function. These findings could provide a new tool for clinicians and policymakers in the future especially if we need to live with COVID-19 for a long time.

Urinary Cystatin C Has Prognostic Value in Peripheral Artery Disease.

Despite its association with adverse outcomes, peripheral artery disease (PAD) remains undertreated. Cystatin C is elevated in patients with renal disease and may be a marker of cardiovascular disease. We examined the prognostic ability of urinary Cystatin C (uCystatinC) in predicting adverse PAD-related events. In this prospective case-control study, urine samples were collected from patients with PAD (n = 121) and without PAD (n = 77). The cohort was followed for 2 years. uCystatinC was normalized to urinary creatinine (uCr) (uCystatinC/uCr; µg/g). The primary outcome was major adverse limb event (MALE; composite of vascular intervention (open or endovascular) or major limb amputation). The secondary outcome was worsening PAD status (drop in ABI ≥ 0.15). Multivariable Cox regression and Kaplan-Meier analyses were performed to assess the prognostic value of uCystatinC/uCr with regards to predicting MALE and worsening PAD status. Our analysis demonstrated that patients with PAD had significantly higher median [IQR] uCystatinC/uCr levels (24.9 µg/g [14.2-32.9] vs. 20.9 µg/g [11.1-27.8], p = 0.018). Worsening PAD status and MALE were observed in 39 (20%) and 34 (17%) patients, respectively. uCystatinC/uCr predicted worsening PAD status with a hazard ratio (HR) of 1.78 (95% CI 1.12-2.83, p = 0.015), which persisted after controlling for baseline demographic and clinical characteristics (adjusted HR 1.79 [95% CI 1.11-2.87], p = 0.017). Patients with high uCystatinC/uCr had a lower 2-year freedom from MALE (77% vs. 89%, p = 0.025) and worsening PAD status (63% vs. 87%, p = 0.001). Based on these data, higher uCystatinC/uCr levels are associated with adverse PAD-related events and have prognostic value in risk-stratifying individuals for further diagnostic vascular evaluation or aggressive medical management.

Urinary cystatin C: pediatric reference intervals and comparative assessment as a biomarker of renal injury among children in the regions with high burden of CKDu in Sri Lanka.

BACKGROUND: Cystatin C (Cys-C) is an emerging biomarker of renal diseases and its clinical use, particularly for screening the communities affected by chronic kidney disease of unknown etiology (CKDu), is hindered due to the lack of reference intervals (RIs) for diverse ethnic and age groups. The present study aimed to define RIs for urinary Cys-C (uCys-C) for a healthy pediatric population in Sri Lanka and in turn compare the renal function of the residential children in CKDu endemic and non-endemic regions in Sri Lanka. METHODS: A cross-sectional study was conducted with 850 healthy children (10-17 years) from selected locations for reference interval establishment, while a total of 892 children were recruited for the comparative study. Urine samples were collected and analyzed for Cys-C, creatinine (Cr) and albumin. Cr-adjusted uCys-C levels were partitioned by age, and RIs were determined with quantile regression (2.5th, 50th and 97.5th quantiles) at 90% confidence interval. RESULTS: The range of median RIs for uCys-C in healthy children was 45.94-64.44 ng/mg Cr for boys and 53.58-69.97 ng/mg Cr for girls. The median (interquartile range) uCys-C levels of children in the CKDu endemic and non-endemic regions were 58.18 (21.8-141.9) and 58.31 (23.9-155.3) ng/mg Cr with no significant difference (P = 0.781). A significant variation of uCys-C was noted in the children across age. CONCLUSIONS: Notably high uCys-C levels were observed in children with elevated proteinuria. Thus, uCys-C could be a potential biomarker in identifying communities at high risk of CKDu susceptibility.

Association of Urine Albumin-Creatinine Ratio and Cystatin C-Based Estimated GFR with Outcomes in Patients with Ischemic Stroke.

BACKGROUND/AIMS: Data about the independent and combined effects of cystatin C-based estimated glomerular filtration rate (eGFRcys) and albuminuria on the risk of poor outcome in stroke patients are limited. The aim was to elucidate how these two renal markers affect the clinical outcomes after ischemic stroke separately and jointly. METHODS: The study subjects consisted of 10,197 patients with ischemic stroke from the third China National Stroke Registry. The study outcomes were all-cause mortality, poststroke disability, recurrence of stroke, and cardiocerebral vascular disease (CVD) composite events. Cox proportional hazard models and multivariable logistic regression model were applied to evaluate the effects of eGFRcys and urine albumin-creatinine ratio (ACR) on these outcomes. RESULTS: Both reduced eGFRcys and increased ACR were independently associated with higher incidences of all-cause death and poststroke disability (p < 0.01). Mildly decreased eGFRcys (60-89 mL/min/1.73 m2) is associated with increased risk of all-cause death and poststroke disability in the presence of high-normal ACR (10-29 mg/g). Patients with both eGFRcys <45 mL/min/1.73 m2 and ACR ≥30 mg/g at baseline had a 6.8-fold risk for all-cause mortality and 3.6-fold risk for poststroke disability, compared with patients with eGFRcys of 90-119 mL/min/1.73 m2 and ACR <10 mg/g. In addition, increased ACR was associated with recurrent stroke and CVD composite event, while reduced eGFRcys showed no relationship with these outcomes. CONCLUSIONS: Both decreased eGFRcys and albuminuria are independent risk factors for all-cause death and poststroke disability. Combining the two markers is useful for improving risk stratification even in those without chronic kidney disease.

Development and Evaluation of Europium-Based Quantitative Lateral Flow Immunoassay for the Chronic Kidney Disease Marker Cystatin-C.

This study aimed to establish a Europium label time-resolved fluorescence immunoassay (TRFIA) to detect the chronic kidney disease (CKD) biomarker Cystatin-C. An Europium based Time resolved fluorescence immunoassay was developed to detect the concentration of Cystatin-C in a urine sample to increase the sensitivity with captured anti-Cystatin-C antibodies immobilized on nitrocellulose membrane and then bonded with detection anti-Cystatin-C labelled with CM-EU, followed by fluorescence measurement using time-resolved fluorometry in 15 min. The performance of this TRFIA was evaluated using the clinical urine serum and compared with the ELISA assays. The linear calibration range was 0.015-32 µg/ml, and the limit of detection (LOD) quantified was 0.0001 µg/ml. This current work has improved the LOD of our previous work from 0.013 µg/ml to 0.001 µg/ml. These results indicated that the CM-EU nanoparticle-based LFIA is rapid, more sensitive, reliable, and reproducible for point-of-care testing of Cys-C concentrations in urine.

Urine Biomarkers for the Assessment of Acute Kidney Injury in Neonates with Hypoxic Ischemic Encephalopathy Receiving Therapeutic Hypothermia.

OBJECTIVE: To evaluate the predictive performance of urine biomarkers for acute kidney injury (AKI) in neonates with hypoxic ischemic encephalopathy (HIE) receiving therapeutic hypothermia. STUDY DESIGN: We performed a multicenter prospective observational study of 64 neonates. Urine specimens were obtained at 12, 24, 48, and 72 hours of life and evaluated for neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C, interleukin-18 (IL-18), tissue inhibitor of metalloproteinases 2 (TIMP2), and insulin-like growth factor-binding protein 7 (IGFBP7). Logistic regression models with receiver operating characteristics for area under the curve (AUC) were used to assess associations with neonatal modified KDIGO (Kidney Disease: Improving Global Outcomes) AKI criteria. RESULTS: AKI occurred in 16 of 64 infants (25%). Neonates with AKI had more days of vasopressor drug use compared with those without AKI (median [IQR], 2 [0-5] days vs 0 [0-2] days; P = .026). Mortality was greater in neonates with AKI (25% vs 2%; P = .012). Although NGAL, KIM-1, and IL-18 were significantly associated with AKI, the AUCs yielded only a fair prediction. KIM-1 had the best predictive performance across time points, with an AUC (SE) of 0.79 (0.11) at 48 hours of life. NGAL and IL-18 had AUCs (SE) of 0.78 (0.09) and 0.73 (0.10), respectively, at 48 hours of life. CONCLUSIONS: Urine NGAL, KIM-1, and IL-18 levels were elevated in neonates with HIE receiving therapeutic hypothermia who developed AKI. However, wide variability and unclear cutoff levels make their clinical utility unclear.

Association Between Graft Function and Urine CXCL10 and Acylcarnitines Levels in Kidney Transplant Recipients.

OBJECTIVE: To evaluate post-transplantation graft functions noninvasively by using urine C-X-C motif chemokine 10 (CXCL10) and metabolome analysis. METHODS: The 65 living-donor kidney-transplant recipients in our cohort underwent renal biopsy to investigate possible graft dysfunction. The patients were divided into 2 groups, according to pathology reports: chronic allograft dysfunction (CAD; n = 18) and antibody-mediated/humoral allograft rejection (AMR; n = 16). The control group was composed of renal transplant recipients with stable health (n = 33). We performed serum creatinine, blood urea nitrogen (BUN), cystatin C, urine protein, CXCL10, and metabolome analyses on specimens from the patients. RESULTS: BUN, creatinine, cystatin C, urine protein, leucine + isoleucine, citrulline, and free/acetyl/propionyl carnitine levels were significantly higher in patients with CAD and AMR, compared with the control individuals. CXCL10 levels were significantly elevated in patients with AMR, compared with patients with CAD and controls. CXCL10 (AUC = 0.771) and cystatin C (AUC = 0.746) were significantly higher in the AMR group, compared with the CAD group (P<.02). CONCLUSIONS: CXCL10 and metabolome analyzes are useful for evaluation of graft functions. Also, CXCL10 might be useful as a supplementary noninvasive screening test for diagnosis of allograft rejection.

The Effect of a Short Course of Tocolytic Indomethacin on Urinary Biomarkers in Premature Infants.

OBJECTIVE: The aim of this study was to determine the effects of a 2-day prenatal course of indomethacin on the premature kidney as reflected by serum creatinine and urinary biomarkers. STUDY DESIGN: Urine of infants ≤32 weeks was collected for the first 14 days and analyzed for cystatin C, neutrophil gelatinase-associated lipocalin, osteopontin, ß2 microglobulin, epidermal growth factor, uromodulin, and microalbumin. Bivariate analysis compared serum creatinine and biomarkers of exposed (INDO) and unexposed (CONT) subjects. RESULTS: Fifty-seven infants (35 CONT and 22 INDO) were studied. The cohorts were similar in gestational age, birthweight, race, gender, nephrotoxic medication exposure, and Apgar's scores. CONT had more dopamine exposure and included more pre-eclamptic mothers (p = 0.005). No difference in creatinine-based acute kidney injury or the log transformed mean, maximum, and minimum values of urinary biomarkers was detected. CONCLUSION: Our findings suggest that a short course of tocolytic indomethacin does not result in neonatal acute kidney injury. KEY POINTS: · A short prenatal course of indomethacin does not result in neonatal acute kidney injury (AKI).. · Urinary EGF might have a promising role as a more sensitive biomarker for early detection of AKI in premature infants..

Serum and urinary biomarkers for early detection of acute kidney injury following Hypnale spp. envenoming.

BACKGROUND: Hump-nosed pit viper (HNV; Hypnale spp.) bites account for most venomous snakebites in Sri Lanka. Acute kidney injury (AKI) is the most serious systemic manifestation (1-10%) following HNV envenoming. We aimed to identify the value of functional and injury biomarkers in predicting the development of AKI early following HNV bites. METHODS: We conducted a prospective cohort study of patients with confirmed HNV envenoming presenting to two large tertiary care hospitals in Sri Lanka. Demographics, bite details, clinical effects, complications and treatment data were collected prospectively. Blood and urine samples were collected from patients for coagulation and renal biomarker assays on admission, at 0-4h, 4-8h, 8-16h and 16-24h post-bite and daily until discharge. Follow-up samples were obtained 1 and 3 months post-discharge. Creatinine (sCr) and Cystatin C (sCysC) were measured in serum and kidney injury molecule-1 (uKIM-1), clusterin (uClu), albumin (uAlb), ß2-microglobulin (uß2M), cystatin C (uCysC), neutrophil gelatinase associated lipocalin (uNGAL), osteopontin (uOPN) and trefoil factor-3 (uTFF-3) were measured in urine. Definite HNV bites were based on serum venom specific enzyme immunoassay. Kidney Disease: Improving Global Outcomes (KDIGO) criteria were used to stage AKI. Two patients had chronic kidney disease at 3 month follow-up, both with pre-existing abnormal sCr, and one developed AKI following HNV envenoming. RESULTS: There were 52 patients with confirmed HNV envenoming; median age 48y (Interquartile range [IQR]:40-59y) and 29 (56%) were male. Median time to admission was 1.87h (IQR:1-2.75h). Twelve patients (23%) developed AKI (AKI stage 1 = 7, AKI stage 2 = 1, AKI stage 3 = 4). Levels of five novel biomarkers, the functional marker serum Cystatin C and the damage markers urinary NGAL, cystatin C, ß2-microglobulin and clusterin, were elevated in patients who developed moderate/severe acute kidney injury. sCysC performed the best at 0-4 h post-bite in predicting moderate to severe AKI (AUC-ROC 0.95;95%CI:0.85-1.0) and no biomarker performed better than sCr at later time points. CONCLUSIONS: sCysC appears to be a better marker than sCr for early prediction of moderate to severe AKI following HNV envenoming.

Urinary concentrations of neonicotinoid insecticides were related to renal tubular dysfunction and neuropsychological complaints in Dry-zone of Sri Lanka.

Neonicotinoids are systemic insecticides used since the 1990's , that possess renal tubular toxicity. We conducted a field-based descriptive study in the North Central Dry-zone of Sri Lanka, where chronic kidney disease (CKD) of unknown etiology has been increasing since the 1990's. To elucidate the relationship between renal tubular dysfunctions and urinary neonicotinoids concentrations, we collected spot urine samples from15 CKD patients, 15 family members, and 62 neighbors in 2015, analyzed two renal tubular biomarkers, Cystatin-C and L-FABP, quantified seven neonicotinoids and a metabolite N-desmethyl-acetamiprid by LC-MS/MS; and we investigated their symptoms using a questionnaire. Cystatin-C and L-FABP had a positive correlation (p < 0.001). N-Desmethyl-acetamiprid was detected in 92.4% of the urine samples, followed by dinotefuran (17.4%), thiamethoxam (17.4%), clothianidin (9.8%), thiacloprid and imidacloprid. Dinotefuran and thiacloprid have never been registered in Sri Lanka. In High Cystatin-C group (> 70 µg/gCre, n = 7), higher urinary concentration of dinotefuran (p = 0.009), and in Zero Cystatin-C group (< LOQ, n = 7), higher N-desmethyl-acetamiprid (p = 0.013), dinotefuran (p = 0.049), and thiacloprid (p = 0.035), and more complaints of chest pains, stomachache, skin eruption and diarrhea (p < 0.05) were found than in Normal Cystatin-C group (n = 78). Urinary neonicotinoids may be one of the potential risk factors for renal tubular dysfunction in this area.

Urinary cystatin C as a biomarker of early renal dysfunction in type 2 diabetic patients.

AIMS: We aimed to evaluate urinary CysC (cystanin c) as an early marker of diabetic nephropathy in patients with type 2 diabetes and investigate the correlation of urinary CysC with albuminuria and GFR. METHODOLOGY: This case-controlled study was conducted on 66 type 2 diabetic patients who were classified according to albuminuria into 3 groups and consisting of 20 healthy subjects as the control group. We assessed urinary CysC, urinary albumin excretion rate (UACR). RESULTS: Urinary CysC levels were significantly higher in normoalbuminuric diabetic compared with healthy control and there was a progressive linear increase in urinary CysC levels with increasing albuminuria in the diabetic patients. Despite insignificant deference in creatinine between participants groups, we observed significant differences between these groups as regard eGFR, urinary CysC, and UACR. Urinary CysC did not have significant correlations with any clinical or biochemical parameters. Moreover, urinary CysC had a statistically significant association with albuminuria and eGFR. CONCLUSION: Urinary CysC levels correlated with UACR and GFR. It is linked to subclinical tubular injury and can be an earlier marker of kidney involvement, even before albuminuria and it is less influenced by non-renal factors. Therefore, Urinary CysC is useful biomarker for early diagnosis of diabetic nephropathy.

The determination of cystatin C in biological samples via the surface plasmon resonance method.

Surface plasmon resonance imaging biosensors have a number of advantages that make them superior to other analytical methods. These include the possibility of label-free detection, speed and high sensitivity to low protein concentrations. The aim of this study was to create and analyze biochips, with the help of which it is possible to test cystatin C in patient urine samples and compare the results with the one-time traditional ELISA method. The main advantage of the surface plasmon resonance imaging method is the possibility of repeated measurements over a long period of time in accordance with clinical practice. The surface of the biochip was spotted with anticystatin C and a negative control of mouse IgG at a ratio of 1:1. The aforementioned biochip was first verified using standard tests and then with patient samples, which clearly confirmed the required sensitivity even for very low concentrations of cystatin C.

The validation of immunoblot SDS-PAGE as a qualitative and quantitative method for the determination of urinary Cystatin C in neonates.

INTRODUCTION: The quantitative determination of urinary Cystatin C (cyst-C) associated with the qualitative analysis of its polymorphisms is an excellent method for early identification of newborns predisposed to renal function impairment. PETIA, PENIA and EIA are the immunometric methods used for the quantitative determination of cyst-C in human biologic fluid but they have limitations and do not allow qualitative analysis. The present study is a validation of Immunoblot SDS-PAGE for the qualitative and quantitative analysis of urinary cyst-C. METHODS: Urine was collected from neonates in the nursey at S. Maria della Misericordia Hospital. Urinary cyst-C was investigated by the immunoblot SDS-PAGE and by reading of optical density. RESULTS: The qualitative analysis showed two different molecular forms: a reactivity at about 70 KDa in all samples and a reactivity at 13 KDa in a limited number of samples. This analysis allows the correlation of the polymorphisms of cyst-C with specific alterations of renal function in newborns. The quantitative analysis is specific, sensitive and accurate. In fact the coefficient of variation for assay precision was 10% and for assay accuracy was ±10%, the detection limit was 0.009 ng/ µL and the calibration line has satisfactory linearity (range 0.02-0.3 ng/ µL). The stability of urinary cyst-C was acceptable, even without the use of protease inhibitors, as long as the assay was performed on freshly recruited urine or immediately after thawing the samples, which had been stored for up to six months. CONCLUSION: Immunoblot SDS-PAGE analysis is a valid method of obtaining a qualitative and quantitative analysis of urinary cyst-C. This method presents unique information about a previously unknown 70 KDa cyst-C form. The assay may offer potential diagnostic information not available with immunometric method.

Cystatin C and Urine Albumin to Creatinine Ratio Predict 5-Year Mortality and Cardiovascular Events in People Living With HIV.

BACKGROUND: Identifying people with HIV (PWH) at risk for chronic kidney disease, cardiovascular events, and death is crucial. We evaluated biomarkers to predict all-cause mortality and cardiovascular events, and measured glomerular filtration rate (mGFR) slope. METHODS: Biomarkers were measured at enrollment. Baseline and 5-year mGFR were measured by plasma iohexol clearance. Outcomes were a composite criterion of all-cause mortality and/or cardiovascular events, and mGFR slope. RESULTS: Of 168 subjects, 146 (87.4%) had undetectable HIV load. Median follow-up was 59.1 months (interquartile range, 56.2-62.1). At baseline, mean age was 49.5 years (± 9.8) and mean mGFR 98.9 mL/min/1.73m2 (± 20.6). Seventeen deaths and 10 cardiovascular events occurred during 5-year follow-up. Baseline mGFR was not associated with mortality/cardiovascular events. In multivariable analysis, cystatin C (hazard ratio [HR], 5.978; 95% confidence interval [CI], 2.774-12.88; P < .0001) and urine albumin to creatinine ratio (uACR) at inclusion (HR, 1.002; 95% CI, 1.001-1.004; P < .001) were associated with mortality/cardiovascular events. Area under receiver operating curve of cystatin C was 0.67 (95% CI, .55-.79) for mortality/cardiovascular event prediction. Biomarkers were not associated with GFR slope. CONCLUSIONS: uACR and cystatin C predict all-cause mortality and/or cardiovascular events in PWH independently of mGFR.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. IMPACT: 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.

The role of cystatin C as a proteasome inhibitor in multiple myeloma.

Objectives: Bone destruction and renal impairment are two frequent complications of multiple myeloma (MM). Cystatin C, an extracellular cysteine proteinase inhibitor, is encoded by the housekeeping gene CST3 and associated with human tumors. The role of cystatin C in multiple myeloma has been revealed recently. The purpose of this study was to explore the role of cystatin C as a proteasome inhibitor in multiple myeloma. Methods : A comprehensive literature review was conducted through Pubmed to summarize the published evidence on cystatin C in multiple myeloma. English literature sources since 1999 were searched, using the terms cystatin C, multiple myeloma. Results: cystatin C is a sensitive indicator for the diagnosis of myeloma nephropathy and has a dual role in myeloma bone disease. Also, cystatin C reflects tumor burden and is strongly associated with prognosis in patients with multiple myeloma. Conclusion: Cystatin C have great diagnostic and prognostic value in multiple myeloma. It can provide a new treatment direction for MM by designing and searching for antagonists of cystatin C or cysteine protease agonists using cystatin C as a therapeutic target.

A Comparative Study of the Use of Dexamethasone, N-acetyl Cysteine, and Theophylline to Ameliorate Renal Ischemia-Reperfusion Injury in Experimental Rat Models: A Biochemical and Immuno-histochemical Approach.

Renal ischemia-reperfusion injury (IRI) is commonly encountered in clinical practice during renal transplantation. In a trial to find the drug that best safeguards the kidney against IRI, dexamethasone (Dex), N-acetyl cysteine (NAC), and theophylline (Theo) were tested in experimental rat models. This study included 105 adult male albino rats, which were randomly assigned to the following five groups: Group I - sham-operated, n = 5, Group II - IRI n = 25, Group III - IRI + Dex n = 25, Group IV - IRI + NAC n = 25, and Group V -IRI + Theo n = 25. IRI was induced for 40 min followed by reperfusion. Rats were sacrificed 1, 2, 4, 6, and 24 h after reperfusion. This was preceded by blood and urine sampling for biochemical study of serum Cystatin C (Cys C), serum creatinine, and urinary Cys C. Kidneys were processed for histopathological evaluation and immune-histochemical staining for Cys C. The expression of Cys C in the proximal tubular cells was significantly lower in the IRI group compared to that of the sham group. There was a significant rise in the levels of serum and urinary Cys C after 1 h in the IRI group, while the rise in creatinine occurred later. Dex was superior to NAC and Theo 24 h after the IR insult, and the serum levels of creatinine and Cys C were significantly lower in this group than the other two drug groups (P <0.001 in both cases). Our study revealed a clear benefit for the use of Dex to ameliorate IRI over NAC and Theo if used immediately following the insult. The effect is evident 24-h after its use. The role of serum Cys C as an early marker of acute kidney injury compared to serum creatinine is confirmed.

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

OBJECTIVE: To 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. METHODS: Prospective-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. RESULTS: Proteomic 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). CONCLUSION: Children 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.