Neutrophil Gelatinase-Associated Lipocalin Is a New and Sensitive Marker of Kidney Function in Chronic Kidney Disease Patients and Renal Allograft Recipients

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) as markers of active lupus nephritis

BACKGROUND AND OBJECTIVES

Despite much research about lupus nephritis, none of the urinary biomarkers has been proven to be truly reflecting lupus nephritis activity, response to treatment, or prognosis. We aimed to study urinary biomarkers in lupus nephritis and test their relation to kidney damage.

PATIENTS AND METHODS

Forty patients with systemic lupus erythematosus (SLE) were divided into two graoups: (1) lupus nephritis group with biopsy-proven proliferative lupus nephritis (classes III and IV) and who did not receive immunosuppressive drugs within the preceding 3 months except for glucocorticoids and (2) lupus non-nephritis group with SLE patients without any renal manifestation. We assessed disease activity by the SLE disease activity index. uNGAL, uKim-1, uNGAL to urinary creatinine excretion (mg/dl), and uKim-1 to urinary creatinine excretion were measured in random spot urine samples at the time of renal biopsy and 6 months after the induction therapy.

RESULTS

The LN group before treatment showed higher levels of uNGAL and uKIM-1 (P-value < 0.001). ROC analysis showed that uNGAL at level of > 59 has a 95 % sensitivity, a 100 % specificity, and an AUC = 0.996 in the ability to diagnose LN. While the uKIM-1 ROC showed that at level of > 1.6, it has an 85 % sensitivity, an 80 % specificity, and an AUC = 0.919. uNGAL and uKIM levels were significantly lower after treatment (P-value < 0.001). No significant correlations were found between urinary markers before and after treatment with other clinical, inflammatory, and serological markers of lupus nephritis.

CONCLUSION

uNGAL, uKIM, uNGAL/Creat ratio, and uKIM/Creat ratio can be used as a predictor and a marker of disease activity for lupus nephritis. Key Points • Renal biopsy is the current standard for diagnosis of lupus nephritis and none of the urinary biomarkers has been fully concluded to have a diagnostic power to reflect the activity or the response to treatment. • However, based on the finding of the current study, uNGAL, uKIM, uNGAL/Creat ratio, and uKIM/Creat ratio showed significant diagnostic performance and were powerful indices of renal involvement in systemic lupus patients and as markers of disease activity.

Renal injury, biomarkers, and myositis, an understudied aspect of disease: prospective study in the MyoCite cohort

Introduction

The mechanisms leading to chronic kidney disease (CKD) in patients with idiopathic inflammatory myopathies (IIMs) are poorly understood. We assessed the prevalence of subclinical renal injury in patients with IIMs, through elevation in biomarker levels of tubular injury and fibrosis (NGAL, KIM1, Activin A, CD163, and Cys-c), and assessed differences between subtypes of IIMs, and the effect of disease activity and duration.

Materials and methods

Clinical data, core set measures, sera and urine were prospectively collected from all patients enrolled in the MyoCite cohort from 2017 to 2021. Twenty healthy subjects (HC) and 16 patients with acute kidney injury (AKI) were included as controls. Baseline and follow up data for IIMs were included. Enzyme-linked immunosorbent assay (ELISA) was used to measure urine NGAL (Human Lipocalin-2/NGAL Duoset ELISA, Cat no: DY1757), KIM1 (Human TIM-1/KIM 1/HAVCR Duoset ELISA, Cat.no: DY1750B), Activin A (Human Activin A Duoset ELISA, Cat no: DY338), CD163 (Human CD163 Duoset ELISA,Cat no: DY1607-05), and Cys-c (Human Cystatin C Duoset ELISA, Cat. no.: DY1196) levels, while eGFR (unit mL/min/1.73 m2) was calculated by the Cockcroft-Gault formula and CKD-EPI formula.

Results

Analysis of 201 visits of 110 adult patients with IIMs indicated higher normalized biomarker levels compared to HCs, and comparable to patients with AKI, with the exception of NGAL, which was higher in the AKI group. Notably 72 (49%) patients with IIMs had eGFR<90; the levels of the 5 biomarkers were comparable between active and inactive IIMs, and different subtypes of IIMs. Similarly, a poor correlation between urine biomarker levels and core set measures of activity and damage was found. Changes in biomarker levels on follow-up did not correlate with eGFR changes.

Discussion

This exploratory analysis of urinary biomarkers identified low eGFR and elevated biomarkers of CKD in nearly half of the patients with IIMs, comparable to patients with AKI and higher than HCs, indicative of potential renal damage in IIMs that may have a lead to complications in other systems.

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.

Prediction of kidney failure in children with chronic kidney disease and obstructive uropathy

BACKGROUND

Obstructive uropathy (OU) is a leading cause of pediatric kidney injury. Accurate prediction of kidney disease progression may improve clinical outcomes. We aimed to examine discrimination and accuracy of a validated kidney failure risk equation (KFRE), previously developed in adults, in children with OU.

METHODS

We identified 118 children with OU and an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 in the Chronic Kidney Disease in Children study, a national, longitudinal, observational cohort. Each patient's 5-year risk of kidney failure was estimated using baseline data and published parameters for the 4- and 8-variable KFREs. Discriminative ability of the KFRE was estimated using the C statistic for time-to-event analysis. Sensitivity and specificity were evaluated across varying risk thresholds.

RESULTS

Among the 118 children, 100 (85%) were boys, with median baseline age of 10 years (interquartile range, 6-14). Median eGFR was 42 mL/min/1.73m 2 (32-53), with a median follow-up duration of 4.5 years (2.7-7.2); 23 patients (19.5%) developed kidney failure within 5 years. The 4-variable KFRE discriminated kidney failure risk with a C statistic of 0.75 (95% CI, 0.68-0.82). A 4-variable risk threshold of ≥ 30% yielded 82.6% sensitivity and 75.0% specificity. Results were similar using the 8-variable KFRE.

CONCLUSIONS

In children with OU, the KFRE discriminated the 5-year risk of kidney failure at C statistic values lower than previously published in adults but comparable with suboptimal values reported in the overall CKiD population. The 8-variable equation did not improve model discrimination or accuracy, suggesting the need for continued research into additional, disease-specific markers.

Evaluation of early biomarkers of renal dysfunction in diabetic patients

Objectives:

To evaluate 2 renal tubular enzymes; urinary neutrophil gelatinase-associated lipocalin (uNGAL), and urinary N-acetyl-beta-D-glucosaminidase (uNAG), and serum Cystatin C as candidate biomarkers for early diagnosis of early stage of diabetic nephropathy (DB) in patients with type 2 diabetes mellitus (T2DM).

Methods:

This cross-sectional study was carried out at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia during the period between May 2017 and May 2018 and was conducted on 86 patients with T2DM. Patients were classified according to their albumin/creatinine ratio (ACR) into 3 groups; a normal albuminuria group with ACR <30 mg/g creatinine, a moderately increased albuminuria group with ACR: 30-299 mg/g creatinine, and a severely increased albuminuria group with ACR ≥300 mg/g. Healthy adults were recruited as a control group. Urine uNGAL, uNAG, and serum Cystatin C were measured in all patients.

Results:

Compared with healthy control, diabetic patients with normal albuminuria excreted significantly higher levels of uNGAL (p<0.001). In addition, significantly elevated uNGAL, uNAG and cystatin C levels were observed in moderately increased albuminuria and severely increased albuminuria groups when compared to the control and normoalbuminuric groups (p<0.001). urinary neutrophil gelatinase-associated lipocalin, urinary N-acetyl-beta-D-glucosaminidase and Cystatin C showed a positive correlation with fasting blood glucose (FBG), HbA1c, duration of diabetes, urea, creatinine, and ACR.

Conclusion:

Our results indicated that uNGAL could be a sensitive biomarker for early renal dysfunction in diabetic patients while uNAG and serum Cystatin C might have prognostic value.

Urinary biomarkers in lupus nephritis

Systemic lupus erythematosus (SLE) is the prototypical autoimmune disease that can affect any organ of the body. Multiple mechanisms may contribute to the pathophysiology of systemic lupus, including failure to remove apoptotic bodies, hyperactivity of self-reactive B and T lymphocytes, abnormal exposure to autoantigens, and increased levels of B-cell stimulatory cytokines. The involvement of the kidney, called lupus nephritis (LN), during the course of the disease affects between 30% and 60% of adult SLE patients, and up to 70% of children. LN is an immune-mediated glomerulonephritis that is a common and serious finding in patients with SLE. Nowadays, renal biopsy is considered the gold standard for classifying LN, besides its degree of activity or chronicity. Nevertheless, renal biopsy lacks the ability to predict which patients will respond to immunosuppressive therapy and is a costly and risky procedure that is not practical in the monitoring of LN because serial repetitions would be necessary. Consequently, many serum and urinary biomarkers have been studied in SLE patients for the complementary study of LN, existing conventional biomarkers like proteinuria, protein/creatinine ratio in spot urine, 24 ​h urine proteinuria, creatinine clearance, among others and non-conventional biomarkers, like Monocyte chemoattractant protein-1 (MCP-1), have been correlated with the histological findings of the different types of LN. In this article, we review the advances in lupus nephritis urinary biomarkers. Such markers ideally should be capable of predicting early sub-clinical flares and could be used to follow response to therapy. In addition, some of these markers have been found to be involved in the pathogenesis of lupus nephritis.

Urinary cell-free mitochondrial and nuclear deoxyribonucleic acid correlates with the prognosis of chronic kidney diseases

Introduction

Cell-free deoxyribonucleic acid DNA (cf-DNA) in urine is promising due to the advantage of urine as an easily obtained and non-invasive sample source over tissue and blood. In clinical practice, it is important to identify non-invasive biomarkers of chronic kidney disease (CKD) in monitoring and surveillance of disease progression. Information is limited, however, regarding the relationship between urine and plasma cf-DNA and the renal outcome in CKD patients.

Methods

One hundred and thirty-one CKD patients were enrolled between January 2016 and September 2018. Baseline urine and plasma cell-free mitochondrial DNA (cf-mtDNA) and cell-free nuclear DNA (cf-nDNA) were isolated using quantitative real-time PCR. Estimated glomerular filtration rate (eGFR) measurement was performed at baseline and 6-month follow-up. Favorable renal outcome was defined as eGFR at 6 months minus baseline eGFR> = 0. Receiver operator characteristics (ROC) curve analysis was performed to assess different samples of cf-DNA to predict favorable renal outcomes at 6 months. A multivariate linear regression model was used to evaluate independent associations between possible predictors and different samples of cf-DNA.

Results

Patients with an advanced stage of CKD has significantly low plasma cf-nDNA and high plasma neutrophil gelatinase-associated lipocalin (NGAL) levels. Low urine cf-mtDNA, cf-nDNA levels and low plasma NGAL were significantly correlated with favorable renal outcomes at 6 months. The urine albumin-creatinine ratio (ACR) or urine protein-creatinine ratio (PCR) level is a robust predictor of cf-mtDNA and cf-nDNA in CKD patients. Baseline urine levels of cf-mtDNA and cf-nDNA could predict renal outcomes at 6 months.

Conclusions

Urinary cf-mtDNA and cf-nDNA may provide novel prognostic biomarkers for renal outcome in CKD patients. The levels of plasma cf-nDNA and plasma NGAL are significantly correlated with the severity of CKD.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1549-x) contains supplementary material, which is available to authorized users.

Activin A: a novel urinary biomarker of renal impairment in multiple myeloma

Renal impairment (RI) is a common complication of multiple myeloma (MM) that significantly affects treatment efficacy and mortality. However, no useful biomarkers for early detection of renal damage in MM exist. Reports indicate that activin A, a multifunctional cytokine of the TGF-β superfamily, is involved in the development and progression of various kidney diseases. In the present study, we measured urinary activin A levels in patients with newly diagnosed MM (NDMM) (n=41), smoldering MM (SMM) (n=10), and monoclonal gammopathy of undetermined significance (MGUS) (n=28), including monoclonal gammopathy of renal significance (MGRS), and assessed the correlation between urinary activin A and several clinical parameters. Urinary activin A, undetectable in healthy volunteers, was significantly increased in NDMM patients but not in patients with SMM and MGUS (97.3, 25.0, and 6.61 mg/gCr, respectively, P<0.05). In all patients with NDMM, urinary activin A levels were significantly reduced after initial treatment regardless of the therapy regimen. There was a significant correlation of urinary activin A with spot urinary protein level (P<0.001) and serum M-protein (P=0.029) but not with estimated glomerular filtration rate (eGFR), serum creatinine (Cr), N-acetyl-glucosaminidase (NAG), and serum activin A level. Histological analysis using renal biopsy samples revealed that activin A, which was absent from normal kidneys, was detected in the renal tubular cells of patients with MGRS. These data suggest that urinary activin A reflects tubular injury in MM and might aid the early detection of RI in plasma cell neoplasms.

Biomarkers for individualized dosage adjustments in immunosuppressive therapy using calcineurin inhibitors after organ transplantation

Calcineurin inhibitors (CNIs), such as cyclosporine A and tacrolimus, are widely used immunosuppressive agents for the prevention of post-transplantation rejection and have improved 1-year graft survival rates by up to 90%. However, CNIs can induce severe reactions, such as acute or chronic allograft nephropathy, hypertension, and neurotoxicity. Because CNIs have varied bioavailabilities, narrow therapeutic ranges, and individual propensities for toxic effects, therapeutic drug monitoring is necessary for all CNIs. Identifying the genetic polymorphisms in drug-metabolizing enzymes will help to determine personalized dosage regimens for CNIs, as CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp, MDR1). CNIs are often concomitantly administered with voriconazole or proton pump inhibitors (PPIs), giving rise to drug interaction problems. Voriconazole and PPIs can increase the blood concentrations of CNIs, and both are primarily metabolized by CYP2C19. Thus, it is expected that interactions between CNIs and voriconazole or PPI would be affected by CYP2C19 and CYP3A5 polymorphisms. CNI-induced acute kidney injury (AKI) is a serious complication of transplantations. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1) are noninvasive urinary biomarkers that are believed to be highly sensitive to CNI-induced AKI. In this article, we review the adverse events and pharmacokinetics of CNIs and the biomarkers related to CNIs, including CYP3A5, CYP2C19, MDR1, NGAL, and KIM-1. We hope that these data will help to identify the optimal biomarkers for monitoring CNI-based immunosuppressive therapy after organ transplantation.

Comparative Assessment of uNGAL, uNAG and Cystatin C As Early Biomarkers in Renal Post-Transplant Patients

Urinary neutrophil gelatinase-associated lipocalin (uNGAL), urinary N-acetyl-bd-glucosaminidase (NAG), urinary α1-microglobulin/creatinine ratio and cystatin C have been suggested as potential early markers of delayed graft function (DGF) following kidney transplantation. We conducted a prospective study in 50 consecutive kidney transplant recipients to evaluate serial changes of these biomarkers within the first week after transplantation and assess their performance in predicting DGF (dialysis requirement during initial post-transplant week) and graft function throughout the first year. Urine samples were collected on post-transplantation days 0, 1, 2, 4, and 7. Statistical analysis: Linear mixed and multivariable regression models, receiver-operating characteristic (ROC), and areas under ROC curves were used. At all-time points, mean urinary NGAL levels were significantly higher in patients developing DGF. Shortly after transplantation (3-6 h), uNGAL and uNAG values were higher in DGF recipients (on average +242 ng/mL; NAG – 6.8 U/mmol creatinine, considering mean dialysis time of 4.1 years) and rose further in the following days, contrasting with prompt function recipients. On Day-1 uNGAL levels accurately predicted DGF (AUC-ROC = 0.93), with a performance higher than serum creatinine (AUC-ROC = 0.76), and similar to cystatin C (AUC-ROC = 0.95). Multivariable analyses revealed that uNGAL levels at days 4 and 7 were strongly associated with one-year serum creatinine level. Urinary NGAL, serum cystatin C is an early marker of graft injury and is independently associated with dialysis requirement within one week after transplantation and one-year graft function.

Evaluation value of neutrophil gelatinase-associated lipocalin for the renal dysfunction of patients with chronic kidney disease: A meta-analysis

OBJECTIVE

The role of neutrophil gelatinase-associated lipocalin (NGAL) for the evaluation of renal function in chronic kidney disease (CKD) has not yet to be determined. We aimed to perform a meta-analysis exploring the correlation between NGAL and glomerular filtration rate (GFR) in CKD patients, and to further identify factors affecting NGAL's performance.

METHODS

Studies dated before November 2017 were retrieved from PubMed, Embase, Web of Science, and the Cochrane Library. A total of 28 relevant studies (involving 3082 patients from 17 countries) were included. The second version of the Quality Assessment for Studies of Diagnostic Accuracy demonstrated that no significant bias had influenced the methodological quality of the included studies.

RESULTS

Neutrophil gelatinase-associated lipocalin showed a strong negative correlation with measured glomerular filtration rate (mGFR). The pooled correlation coefficient (r) with corresponding 95% confidence intervals for the correlation between serum NGAL (sNGAL) and GFR was -0.48, meanwhile that for urine NGAL (uNGAL) and GFR was -0.34. However, NGAL's performance is different in subgroups restricted by clinical settings, race, sex, age, and staging of renal function.

CONCLUSION

Neutrophil gelatinase-associated lipocalin could be a renal function evaluation marker for patients with renal dysfunction in CKD. Compared with uNGAL, there was a significant negative correlation between sNGAL and GFR. The performances of sNGAL and uNGAL were restricted by clinical factors that should be considered in regards to the sampling source selection.

Kidney injury biomarkers 5 years after AKI due to pediatric cardiac surgery

BACKGROUND

We previously reported that children undergoing cardiac surgery are at high risk for long-term chronic kidney disease (CKD) and hypertension, although postoperative acute kidney injury (AKI) is not a risk factor for worse long-term kidney outcomes. We report here our evaluation of renal injury biomarkers 5 years after cardiac surgery to determine whether they are associated with postoperative AKI or long-term CKD and hypertension.

METHODS

Children aged 1 month to 18 years old undergoing cardiopulmonary bypass were recruited to this prospective cohort study. At 5 years after cardiac surgery, we measured urine interleukin-18, kidney injury molecule-1, monocyte chemoattractant protein-1, YKL-40, and neutrophil gelatinase-associated lipocalin (NGAL). Biomarker levels were compared between patients with AKI and those without. We also performed a cross-sectional analysis of the association between these biomarkers with CKD and hypertension.

RESULTS

Of the 305 subjects who survived hospitalization, four (1.3%) died after discharge, and 110 (36%) participated in the 5-year follow-up. Of these 110 patients, 49 (45%) had AKI. Patients with versus those without postoperative AKI did not have significantly different biomarker concentrations at 5 years after cardiac surgery. None of the biomarker concentrations were associated with CKD or hypertension at 5 years of follow-up, although CKD and hypertension were associated with a higher proportion of participants with abnormal NGAL levels.

CONCLUSIONS

Postoperative pediatric AKI is not associated with urinary kidney injury biomarkers 5 years after surgery. This may represent a lack of chronic renal injury after AKI, imprecise estimation of the glomerular filtration rate, the need for longer follow-up to detect chronic renal damage, or that our studied biomarkers are inadequate for evaluating subclinical chronic renal injury.

Spleen contributes significantly to increased circulating levels of fibroblast growth factor 23 in response to lipopolysaccharide-induced inflammation

Background

Circulating levels of fibroblast growth factor 23 (FGF23) increase progressively and correlate with systemic inflammation in chronic kidney disease (CKD). The aim of this study was to identify and characterize the causal relationship between FGF23 and inflammation in CKD.

Methods

Circulating FGF23 and inflammatory cytokines were correlated in healthy subjects and patients with varying levels of CKD. In addition, FGF23 expression in blood and solid organs was measured in normal mice that were exposed acutely (one time) or chronically (2-week) to low-dose lipopolysaccharide (LPS); chronic exposure being either sustained (subcutaneous pellets), intermittent (daily injections) or combined sustained plus acute (subcutaneous pellets plus acute injection on the day of sacrifice). Blood was analyzed for both terminal (cFGF23) and intact (iFGF23) FGF23 levels. Solid tissues were investigated with immunohistochemistry, enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction.

Results

FGF23 levels correlated significantly with neutrophil gelatinase-associated lipocalin ( r = 0.72, P < 0.001), C-reactive protein ( r = 0.38, P < 0.001), tumor necrosis factor-α ( r = 0.32, P = 0.001) and interleukin-6 ( r = 0.48, P < 0.001). Acute LPS administration increased tissue FGF23 mRNA and plasma levels of cFGF23 but not iFGF23. Neither chronic sustained nor chronic pulsatile LPS increased the tissue or circulating levels of FGF23. However, acute on chronic LPS raised tissue FGF23 mRNA and both circulating cFG23 and iFGF23. Interestingly, the spleen was the major source of FGF23.

Conclusion

Acute on chronic exposure to LPS stimulates FGF23 production in a normal mouse model of inflammation. We provide the first evidence that the spleen, under these conditions, contributes substantially to elevated circulating FGF23 levels.

Oxidative Stress in Kidney Diseases: The Cause or the Consequence?

Exaggerated oxidative stress (OS) is usually considered as a disturbance in regular function of an organism. The excessive levels of OS mediators may lead to major damage within the organism’s cells and tissues. Therefore, the OS-associated biomarkers may be considered as new diagnostic tools of various diseases. In nephrology, researchers are looking for alternative methods replacing the renal biopsy in patients with suspicion of chronic kidney disease (CKD). Currently, CKD is a frequent health problem in world population, which can lead to progressive loss of kidney function and eventually to end-stage renal disease. The course of CKD depends on the primary disease. It is assumed that one of the factors influencing the course of CKD might be OS. In the current work, we review whether monitoring the OS-associated biomarkers in nephrology patients can support the decision-making process regarding diagnosis, prognostication and treatment initiation.

Kinetic Glomerular Filtration Rate Estimation Compared With Other Formulas for Evaluating Acute Kidney Injury Stage Early After Kidney Donation

OBJECTIVES

Kinetic glomerular filtration rate estimation may have more power and versatility than the Modification of Diet in Renal Disease or Cockcroft-Gault formula for evaluating kidney function when plasma creatinine fluctuates rapidly. After kidney donation, glomerular filtration rate rapidly fluctuates in otherwise healthy patients. We compared 3 formulas for estimating glomerular filtration rate: kinetic, Modification of Diet in Renal Disease, and Cockcroft-Gault, for determining stages of acute kidney injury early after kidney donation.

MATERIALS AND METHODS

In 42 living kidney donors, we measured serum creatinine, cystatin C, neutrophil gelatinase-associated lipocalin, and glomerular filtration rates before uninephrectomy and 3 days afterward. To estimate glomerular filtration rate, we used Cockcroft-Gault, Modification of Diet in Renal Disease, and kinetic equations. We sought the most accurate formula for staging acute kidney injury according to the risk, injury, failure, loss, and end-stage criteria.

RESULTS

The kinetic glomerular filtration rate model found more cases of stage 3 acute kidney injury than did the Modification of Diet in Renal Disease or Cockcroft-Gault formula. Receiver operating characteristic curves showed that the kinetic glomerular filtration rate model had more sensitivity and specificity than the Cockroft-Gault formula for discriminating among risk, injury, failure, loss, and end-stage criteria stages of acute kidney injury, based on serum creatinine changes. On day 2 after donation, a more sensitive marker with a shorter half-life (serum neutrophil gelatinase-associated lipocalin) was more significantly correlated with kinetic glomerular filtration rate estimation.

CONCLUSIONS

The kinetic glomerular filtration rate model was able to discriminate stages of acute kidney injury early after kidney donation according to risk, injury, failure, loss, and end-stage criteria better than the Modification of Diet in Renal Disease or Cockcroft-Gault formulas. The kinetic model detected failure-stage acute kidney injury ≥ 1 to 2 days earlier than the MDRD formula, CG formula detected no failure.

Predicting acute kidney injury: current status and future challenges

Acute kidney injury (AKI) is characterized by an acute decline in renal function and is associated to increased mortality rate, hospitalization time, and total health-related costs. The severity of this ‘fearsome’ clinical complication might depend on, or even be worsened by, the late detection of AKI, when the diagnosis is based on the elevation of serum creatinine (SCr). For these reasons, in recent years a great number of new tools, biomarkers and predictive models have been proposed to clinicians in order to improve diagnosis and prevent the development of AKI. The purpose of this narrative paper is to review the current state of the art in prediction and early detection of AKI and outline future challenges.

The impact of calcineurin inhibitors on neutrophil gelatinase-associated lipocalin and fibroblast growth factor 23 in long-term kidney transplant patients

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL), a protein with bacteriostatic functions rapidly excreted from stimulated or damaged epithelial cells, is elevated in acute and chronic kidney disease. A calcineurin dependent signaling pathway for fibroblast growth factor 23 (FGF23) has been revealed, but the effect of calcineurin inhibitors (CNIs) on the levels of NGAL and markers of mineral metabolism in long-term kidney transplant patients has not been explored.

METHODS

In a cross-sectional study, 39 patients who received a first kidney transplant more than 10 years ago were split into two groups based on whether (n=28) or not (n=11) they used CNIs. Only patients with well-functioning grafts defined as an estimated glomerular filtration rate ≥45 mL/min per 1.73 m² were included.

RESULTS

The median levels of NGAL, intact parathyroid hormone (iPTH), and iFGF23 were significantly higher in CNI users vs CNI nonusers, 167.0 (134.0-235.0) ng/mL vs 105.0 (91.3-117.0) ng/mL, P<.001, 13.8 (10.0-17.3) pmol/L vs 8.4 (6.4-9.9) pmol/L, P=.003, and 81.6 (56.4-116.5) pg/mL vs 61.8 (43.3-72.1) pg/mL, P=.04 respectively.

CONCLUSIONS

The median levels of iFGF23 were higher in CNI users compared to CNI nonusers giving support to the notion of a CNI induced FGF23 resistance in the parathyroid. The net result of CNIs side effects needs to be further explored.

Plasma neutrophil gelatinase-associated lipocalin (NGAL) is an indicator of interstitial damage and a predictor of kidney function worsening of chronic kidney disease in the early stage: a pilot study

BACKGROUND

The aim of this study was to examine whether plasma neutrophil gelatinase-associated lipocalin (NGAL) levels predict the outcome of kidney function and correlate with the severity of tubulointerstitial damages in patients with chronic kidney disease (CKD).

METHODS

In this prospective 18-month cohort study of 112 patients with CKD between 2010 and 2011, associations between plasma NGAL levels and estimated glomerular filtration ratio (eGFR), further worsening of kidney function and histological lesion on kidney biopsy were investigated.

RESULTS

Serum levels of creatinine and eGFR before the study were 1.48 ± 0.65 mg/dl and 42.6 ± 22.0 ml/min/1.73 m². Median plasma NGAL level was 148.5 (83.75-248.25) ng/ml and showed no correlation with eGFR or age. 87 out of 112 patients were able to follow up for 18 months. Patients with higher levels of NGAL (>107.8 ng/ml) showed significantly more decrease in eGFR in CKD stage 1 or 2 than those with lower levels of NGAL (≦107.8 ng/ml), while there was no difference in change in eGFR in CKD stage 3-5 between patients with higher and lower levels of NGAL. In the kidney biopsy of 27 patients out of enrolled patients, plasma NGAL levels correlated significantly with the degree of interstitial cell infiltration and fibrosis, but did not correlate with that of glomerular sclerosis. In ROC analysis, plasma NGAL levels predicted tubulointerstitial cell infiltrations more accurately [AUC = 0.8300 than eGFR (AUC = 0.716)].

CONCLUSION

Plasma NGAL is a useful marker of interstitial lesions in patients with CKD and a predictor of further kidney worsening in the early CKD stage.

Urinary NGAL for the diagnosis of the renal injury from multiple myeloma

OBJECTIVES

Neutrophil gelatinase-associated lipocalin (NGAL) has been proved as a sensitive biomarker in acute and chronic renal injury. Renal impairment is a common complication of multiple myeloma (MM). We attempt to assess the value of NGAL for the early and accurate diagnosis of renal injury in MM patients.

METHODOLOGY

Forty-five MM patients with CKD stage I to V(MM-renal group), 20 MM patients with normal kidney function (MM-non-renal group), and 37 healthy volunteers (healthy control) were compared for serum and urinary NGAL and other renal injury biomarkers (Creatinine[CRE]; Cystatin-C [CysC]; N-acetyl-beta-D-glucosaminidase [NAG]). Other biomarkers reflect the inflammation and tumor burden like high-sensitivity C-reactive protein(hs-CRP) and urine free light chain were also detected.

RESULTS

Among the biomarkers of renal injury, the assessment of serum CysC, CRE and NGAL was a reliable tool to distinguish MM-renal from MM-non-renal. Both serum and urinary NGAL levels were higher in MM-renal patients than in MM-non-renal or healthy controls (187.10 (45.60-699.60) vs 136.70 (47.70-216.50) vs 117.7 (69.3-192.3), P< 0.01; 37.50 (6.30-412.10) vs 18.00 (0.50-66.50) vs 11.2 (0.9-69.1), P< 0.01). Univariate analysis showed that both serum (Odds Ratio = 1.009; 95%CI 1.002-1.017; P= 0.018) and urinary NGAL (Odds Ratio = 1.038; 95%CI 1.003-1.073; P= 0.031) as well as serum CysC (Odds Ratio = 9.875; 95%CI 1.685-57.882; P= 0.011) were strong predictors for the risk of renal injury in MM patients. Moreover, the urinary NGAL level was negatively correlated with estimated glomerular filtration rate (eGFR) (r= -0.586, P= 0.00003) and has a tendency towards positive correlation with urine free light chain (r = 0.235, P = 0.124) and hs-CRP (r = 0.379, P = 0.074).

CONCLUSIONS

The present study demonstrated that urinary NGAL was not superior to serum NGAL in distinguishing MM-renal group from MM-non-renal group. And it could be considered an independent predictor of renal injury from multiple myeloma reflecting active kidney damage, tumor burden, and inflammation.

Short-Term Non-Steroid Anti-Inflammatory Drug Use in Spondyloarthritis Patients Induces Subclinical Acute Kidney Injury: Biomarkers Study

BACKGROUND

Non-steroid anti-inflammatory drug (NSAID) usage is associated with kidney injury. Rise in serum creatinine (sCr) often represents irreversible process. Thus to assess the early effects of regular NSAID use, we studied sensitive serum and urine biomarkers of kidney injury.

METHODS

In a protocol-based intervention study, 103 subjects were enrolled in 3 mutually exclusive groups. Group 1 included 37 healthy controls having minimal baseline NSAID exposure as per a definition, and group 2 had 41 spondyloarthritis (SpA) patients on regular NSAID therapy for >3 months. Group 3 included 25 SpA patients having minimal NSAID exposure at baseline. Blood and urine samples were collected from all the 3 groups at baseline. Furthermore, group 3 was started on 6-week regular NSAID therapy, and blood and urine samples were re-collected at 1, 6, and 12 weeks. Baseline normal kidney function as per the definition was ensured in all the subjects. Creatinine, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin-C, and microalbumin were measured in urine and serum samples to assess kidney injury.

RESULTS

Kidney injury biomarkers were 2-3-fold higher in SpA patients using regular NSAID therapy compared to healthy controls and SpA patients having minimal NSAID exposure (uKIM-1 and uNGAL p < 0.0001, sKIM-1 and sNGAL p = 0.001). There was no difference in sCr and estimated glomerular filtration rate using Cockcroft-Gault equation between the groups. In SpA patients started on 6 weeks of regular NSAID (group 3), biomarker levels started rising at week 1 and showed a significant rise at week 6. The levels in the patients that stopped NSAID use at 6 weeks showed reversibility at 12 weeks.

CONCLUSIONS

Regular NSAID use in SpA patients induces subclinical kidney injury represented by rise in biomarkers. These levels start rising as early as 7 days of regular NSAID use and are reversible on stopping the drug.

The Kidney and Periodontal Disease (KAPD) study: A pilot randomized controlled trial testing the effect of non-surgical periodontal therapy on chronic kidney disease

INTRODUCTION

Chronic kidney disease (CKD) remains a prevalent public health problem that disproportionately affects minorities and the poor, despite intense efforts targeting traditional risk factors. Periodontal diseases are common bacterial plaque-induced inflammatory conditions that can respond to treatment and have been implicated as a CKD risk factor. However there is limited evidence that treatment of periodontal disease slows the progression of CKD.

METHODS/DESIGN

We describe the protocol of the Kidney and Periodontal Disease (KAPD) study, a 12-month un-blinded, randomized, controlled pilot trial with two intent-to-treat treatment arms: 1. immediate intensive non-surgical periodontal treatment or 2. rescue treatment with delayed intensive treatment. The goals of this pilot study are to test the feasibility of conducting a larger trial in an ethnically and racially diverse, underserved population (mostly poor and/or low literacy) with both CKD and significant periodontal disease to determine the effect of intensive periodontal treatment on renal and inflammatory biomarkers over a 12-month period.

RESULTS

To date, KAPD has identified 634 potentially eligible patients who were invited to in-person screening. Of the 83 (13.1%) of potentially eligible patients who attended in-person screening, 51 (61.4%) were eligible for participation and 46 enrolled in the study. The mean age of participants is 59.2years (range 34 to 73). Twenty of the participants (43.5%) are Black and 22 (47.8%) are Hispanic.

DISCUSSION

Results from the KAPD study will provide needed preliminary evidence of the effectiveness of non-surgical periodontal treatment to slow CKD progression and inform the design future clinical research trials.

Effect of Rhizoma Polygoni Cuspidati and Ramulus Cinnamomi compatibility on uric acid metabolism and urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in rats with hyperuricemia

OBJECTIVE

To explore the effects of Rhizoma Polygoni Cuspidati and Ramulus Cinnamomi compatibility (PR) on uric acid metabolism and the expression of urinary neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in rats with hyperuricemia.

METHODS

Seventy male Sprague Dawley (SD) rats were randomly divided into 7 groups with 10 rats per group, including the normal group, model group, allopurinol group, benzbromarone group and PR groups at 3 doses (3.5, 7, 14 g/kg). Except the normal group, rats of the other groups were intragastrically administered 100 mg/kg hypoxanthine and 250 mg/kg ethambutol, and subcutaneously injected with 200 mg/kg potassium oxonate. All rats were continuously modeled for 17 days, and gavaged with corresponding drugs. The rats of the normal and model groups were gavaged with saline, once a day, for 2 weeks. The levels of serum uric acid (SUA), blood urea nitrogen (BUN) and creatinine (Cr) were determined. In addition, the contents of NGAL and KIM-1 in urine and the mRNA and protein expressions of xanthine oxidase (XOD) in liver of hyperuricemia rats were measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. Moreover, the pathological changes of kidney were analyzed by hematoxylin and eosin (HE) stain method.

RESULTS

Compared with the normal group, the levels of SUA, BUN, NGAL and KIM-1 and the expressions of hepatic XOD mRNA and protein in the hyperuricemia rats were increased signifificantly (P<0.01). PR signifificantly decreased the levels of SUA, BUN, NGAL and KIM-1 and down-regulated the mRNA and protein expressions of hepatic XOD (P<0.05 or P<0.01). In addition, the pathological changes of kidney were signifificantly suppressed by oral administration of PR.

CONCLUSIONS

PR ameliorated uric acid metabolism and protected renal function, the underlying mechanism was mediated by decreasing the levels of SUA, BUN, NGAL and KIM-1, inhibiting the expression of hepatic XOD and ameliorating the pathological change of kidney.

Screening of renal dysfunction among Burkitt lymphoma survivors by novel markers

BACKGROUND

Burkitt lymphoma (BL) represents the most common pathological type of non-Hodgkin lymphoma in our region. Recently, high success rates have been achieved in BL treatment. Little is known about long-term renal dysfunction in this vulnerable group. In the present study, we tried to detect early chronic kidney diseases (CKD) among BL survivors by using novel screening modalities.

PATIENTS AND METHODS

we investigated 53 children (aged 10 ± 2.8 years, 34 boys) who successfully treated for Burkitt lymphoma, based on LMB96 protocol, as "patient group" and 30 children as control. All eligible participants were subjected to history taking, physical assessment, and routine laboratory investigations including urine analysis, serum creatinine. Estimated glomerular filtration rates using new Schwartz formula (GFR_CKD) were calculated and chronic kidney disease prevalence was diagnosed accordingly. Also, serum Cystatin-C (Cys-C) and neutrophil-gelatinase-associated Lipocalin (NGAL) were determined as novel markers aiming at early and accurate detection of CKD in BL survivors.

RESULTS

After 18.3 ± 5.2 months of BL cytotoxic therapy completion, almost one fifth of asymptomatic BL survivors showed evidence of subclinical CKD when estimated GFR_CKD (16.9%), serum Cystatin-C (15%) and serum neutrophil-gelatinase-associated Lipocalin (18.8%) were used for kidney function monitoring. This prevalence was four to fivefolds higher than that detected by routine serum creatinine screening (3.7%). Significant persistent albuminuria was diagnosed at 4/53 (7.5.3%) of BL survivors and asymptomatic hypertension was reported in 1/53 (1.9%) of them compared to none of the controls. Positive correlation could be displayed between serum Cys-C and serum NGAL. Conversely, negative correlations between both of them and estimated GFR_CKD were documented.

CONCLUSION

Novel modalities such new Schwartz formula (GFRCKD) estimation, serum Cys-C, and serum NGAL assessment should be incorporated in the routine follow-up screening for CKD among BL survivors for accurate diagnosis of such detrimental morbidity.

Neutrophil Gelatinase-Associated Lipocalin, Fibroblast Growth Factor 23, and Soluble Klotho in Long-Term Kidney Donors

Background

The best treatment for end-stage renal disease (ESRD) is kidney transplantation. Twenty-seven percent of transplantations in Norway are from living donors. Recent studies have shown an increased risk of ESRD and increased mortality in donors. The aim of this study was to determine if the levels of the new biomarkers neutrophil gelatinase-associated lipocalin (NGAL), soluble Klotho (sKlotho), and fibroblast growth factor 23 (FGF23) are changed in kidney donors with normal kidney function defined as an estimated glomerular filtration rate (eGFR) >60 ml/min/1.73 m² compared to patients with chronic kidney disease (CKD) stages 3-5 and healthy controls.

Methods

This is a cross-sectional, observational, single-center study including 35 kidney donors with an eGFR ≥60 ml/min/1.73 m² 5 years after donation, 22 patients with CKD stage 3 (eGFR 30-59 ml/min/1.73 m²), 18 patients with CKD stage 4 (eGFR 15-29 ml/min/1.73 m²), 20 patients with CKD stage 5 (eGFR <15 ml/min/1.73 m²), and 35 controls comparing levels of biomarkers in long-term kidney donors with those in CKD patients and healthy controls.

Results

The level of log NGAL was significantly higher in donors than in healthy controls (2.02 ± 0.10 vs. 1.89 ± 0.10 ng/ml; p < 0.001), and the level increased with declining kidney function. The log FGF23 level was nonsignificantly higher in donors than in controls, but it significantly increased with declining kidney function. The log sKlotho levels were significantly lower in patients with CKD stages 4 and 5 than in controls, but no difference was revealed between controls and donors.

Conclusion

Kidney donors have significantly higher levels of NGAL than healthy controls after a median of 15 years (range 5-38). NGAL could be a valuable diagnostic marker in the future. FGF23 and sKlotho were not significantly different between donors and controls.

Prognostic Value of Levels of Urine Neutrophil Gelatinase-associated Lipocalin and Interleukin-18 in Patients With Delayed Graft Function After Kidney Transplantation

OBJECTIVE

The aim of our study was to examine how serial urine neutrophil gelatinase-associated lipocalin (uNGAL) and interleukin (IL)-18 concentrations change over time after kidney transplantation and whether we can use them to predict delayed graft function (DGF).

METHODS

Spot urine samples for the NGAL and IL-18 tests were taken at 4, 12, 24, 48, and 72 hours after transplantation from every patient at hospital presentation. Urine samples were tested for NGAL by a chemiluminescence assay kit on the ARCHITECT I2000 immunology analyzer. IL-18 were measured by a quantitative immunoenzymatic assay kit. Serum samples for the creatinine measurement were taken at 24, 48, and 72 hours after kidney transplantation. Serum samples were tested for creatinine on the Olympus analyzer 5821 by alkaline picric acid method. The patients were divided into 2 groups: DGF group and non-DGF group.

RESULTS

The urine NGAL levels were increased in DGF group at all points over the follow-up period. There are differences (P < .05) in NGAL concentrations between DGF (n = 21) and non-DGF groups (n = 102). However, urine samples from the DGF group (n = 21) had increased IL-18 concentrations at 4, 12, 24, and 48 hours postoperatively compared with non-DGF group samples (n = 102) (P < .05). There were obvious distinctions (P < .05) of serum creatinine (SCr) levels in 24 hours between the DGF (n = 21) and non-DGF groups (n = 102). The specificity and positive predictive value of NGAL in the DGF diagnosis increased with time, but the sensitivity and negative predictive value do not change. The specificity, sensitivity, positive predictive, value and negative predictive value of IL-18 in the DGF diagnosis changed irregularly at multiple time points after transplant. The positive predictive value and negative predictive value of 24-hour SCr were 47.4% and 95.7%, respectively. The positive predictive value and negative predictive value of combination of NGAL, IL-18, and SCr (area under the receiver-operating characteristic curve = 0.984; 95% CI, 0.887-0.994) were 90.9% and 100%, respectively. Overall, the combination of NGAL, IL-18, and SCr was found to have a significantly better positive predictive value than all the other combination assays (P < .05). In addition, there were obvious distinction of the negative predictive value of NGAL and IL-18 combination compared with those of other combinations (P < .05).

CONCLUSIONS

The combination of NGAL, IL-18, and SCr measurements after initiation of treatment may be highly effective for risk stratification in patients with DGF. The combination may be useful to cover the complete diagnostic window of patients presenting with DGF.

Common chronic conditions do not affect performance of cell cycle arrest biomarkers for risk stratification of acute kidney injury

Background

Identification of acute kidney injury (AKI) can be challenging in patients with underlying chronic disease, and biomarkers often perform poorly in this population. In this study we examined the performance characteristics of the novel biomarker panel of urinary tissue inhibitor of metalloproteinases-2 (TIMP2) and insulin-like growth factor-binding protein 7 ([IGFBP7]) in patients with a variety of comorbid conditions.

Methods

We analyzed data from two multicenter studies of critically ill patients in which [TIMP2]•[IGFBP7] was validated for prediction of Kidney Disease: Improving Global Outcomes (KDIGO) Stage 2 or 3 AKI within 12 h. We constructed receiver operating characteristic (ROC) curves for AKI prediction both overall and by comorbid conditions common among patients with AKI, including diabetes mellitus, congestive heart failure (CHF) and chronic kidney disease (CKD).

Results

In the overall cohort of 1131 patients, 139 (12.3%) developed KDIGO Stage 2 or 3 AKI. [TIMP2]•[IGFBP7] was significantly higher in AKI versus non-AKI patients, both overall and within each comorbidity subgroup. The AUC for [TIMP2]•[IGFBP7] in predicting AKI was 0.81 overall. Higher AUC was noted in patients with versus without CHF (0.89 versus 0.79; P = 0.026) and CKD (0.91 versus 0.80; P = 0.024).

Conclusions

We observed no significant impairment in the performance of cell cycle arrest biomarkers due to the presence of chronic comorbid conditions.

Role of plasma neutrophil gelatinase-associated lipocalin as an emerging biomarker of acute renal failure following kidney transplantation and its correlation with plasma creatinine

Introduction: Graft function early after kidney transplantation is an important parameter in determining the outcome of operation. Urinary and plasma neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin protein family, has been advocated as a sensitive, early biomarker for predicting early renal graft after transplantation. The functions of NGAL appears to be expressed in stress conditions and in tissues undergoing involution. It rapidly accumulates in the kidney tubules and urine after nephrotoxic and ischemic insults.

Objectives: This study aimed to examine the prognostic role of NGAL early after renal transplantation.

Patients and Methods: A total of 37 kidney recipients were enrolled from a teaching centre in Tabriz within a 6-month period of time. Plasma NGAL was measured immediately before and at 6 and 12 hours post-transplantation. Changes of serum creatinine were documented daily within the first week post-operation. Acute kidney injury (AKI)/graft rejection during the first week after transplantation was the outcome variable.

Results: There were 22 males (59.5%) and 15 females (40.5%) with the mean age of 34.93 ± 14.97 years (range: 12-59) in the study group. AKI/graft rejection developed in 12 patients (32.4%). The mean post-transplantation plasma NGAL levels and serum creatinine at all time points were significantly higher in patients with AKI/graft rejection. The best prognostic role was found for plasma NGAL at 12 hours (sensitivity = 100%, specificity = 92%; cut-off value = 309 ng/ml), far better than the prognostic accuracy of corresponding serum creatinine (sensitivity = 66.7%, specificity = 61.9%).

Conclusion: Plasma NGAL, particularly 12 hours after transplantation, is a very sensitive and specific biomarker for predicting acute renal injury.

Urinary biomarkers of chronic allograft nephropathy

PURPOSE

Chronic allograft nephropathy (CAN) is widely accepted as the leading cause of renal allograft loss after the first year post transplantation. This study aimed to identify urinary biomarkers that could predict CAN in transplant patients.

EXPERIMENTAL DESIGN

The study included 34 renal transplant patients with histologically proven CAN and 36 renal transplant patients with normal renal function. OrbiTrap MS was utilized to analysis a urinary fraction in order to identify other members of a previously identified biomarker tree . This novel biomarker pattern offers the potential to distinguish between transplant recipients with CAN and those with normal renal function.

RESULTS

The primary node of the biomarker pattern was reconfirmed as β2 microglobulin. Three other members of this biomarker pattern were identified: neutrophil gelatinase-associated lipocalin, clusterin, and kidney injury biomarker 1. Significantly higher urinary concentrations of these proteins were found in patients with CAN compared to those with normal kidney function.

CONCLUSIONS AND CLINICAL RELEVANCE

While further validation in a larger more-diverse patient population is required to determine if this biomarker pattern provides a potential means of diagnosing CAN by noninvasive methods in a clinical setting, this study clearly demonstrates the biomarkers' ability to stratify patients based on transplant function.

Measurement of neutrophil gelatinase-associated lipocalin (NGAL) in patients with non-communicable diseases: any additional benefit?

AIM

Chronic kidney disease (CKD) is one of the major complication from non-communicable diseases (NCD), such as diabetes or hypertension. We aimed to determine if routine measurement of neutrophil gelatinase-associated lipocalin (NGAL) in NCD patients could provide additional benefit for diagnosing kidney disease.

METHODS

Fasting serum NGAL, urea, creatinine, uric acid and albumin were measured in 298 NCD patients. Estimated glomerular filtration rate (e-GFR) was calculated using the CKD-EPI equation. Multiple linear regression modeling was used for analysis.

RESULTS

CKD patients have the highest levels of NGAL than the other NCD patients (p < 0.001). Although NGAL was significantly related to e-GFR, creatinine, urea and albumin in CKD-patients (p < 0.001) and not in the other NCD patients (p > 0.05), only serum creatinine predicted NGAL levels in CKD-patients (p < 0.001).

CONCLUSION

NGAL level is best associated with serum creatinine only in patients with CKD and NGAL measurement may not be cost effective as a routine kidney function test in NCD patients in under-resourced economies.

Urine Biomarkers and Perioperative Acute Kidney Injury: The Impact of Preoperative Estimated GFR

BACKGROUND

The interaction between baseline kidney function and the performance of biomarkers of acute kidney injury (AKI) on the development of AKI is unclear.

STUDY DESIGN

Post hoc analysis of prospective cohort study.

SETTING & PARTICIPANTS

The 1,219 TRIBE-AKI Consortium adult cardiac surgery cohort participants.

PREDICTOR

Unadjusted postoperative urinary biomarkers of AKI measured within 6 hours of surgery.

OUTCOME

AKI was defined as AKI Network stage 1 (any AKI) or higher, as well as a doubling of serum creatinine level from the preoperative value or the need for post-operative dialysis (severe AKI).

MEASUREMENTS

Stratified analyses by preoperative estimated glomerular filtration rate (eGFR) ≤ 60 versus > 60mL/min/1.73m(2).

RESULTS

180 (42%) patients with preoperative eGFRs≤60mL/min/1.73m(2) developed clinical AKI compared with 246 (31%) of those with eGFRs>60mL/min/1.73m(2) (P<0.001). For log2-transformed biomarker concentrations, there was a significant interaction between any AKI and baseline eGFR for interleukin 18 (P=0.007) and borderline significance for liver-type fatty acid binding protein (P=0.06). For all biomarkers, the adjusted relative risk (RR) point estimates for the risk for any AKI were higher in those with elevated baseline eGFRs compared with those with eGFRs≤60mL/min/1.73m(2). However, the difference in magnitude of these risks was low (adjusted RRs were 1.04 [95% CI, 0.99-1.09] and 1.11 [95% CI, 1.07-1.15] for those with preoperative eGFRs≤60mL/min/1.73m(2) and those with higher eGFRs, respectively). Although no biomarker displayed an interaction for baseline eGFR and severe AKI, log2-transformed interleukin 18 and kidney injury molecule 1 had significant adjusted RRs for severe AKI in those with and without baseline eGFRs≤60mL/min/1.73m(2).

LIMITATIONS

Limited numbers of patients with severe AKI and post-operative dialysis.

CONCLUSIONS

The association between early postoperative AKI urinary biomarkers and AKI is modified by preoperative eGFR. The degree of this modification and its impact on the biomarker-AKI association is small across biomarkers. Our findings suggest that distinct biomarker cutoffs for those with and without a preoperative eGFR≤60mL/min/1.73m(2) is not necessary.

Prognostic significance of urinary NGAL in chronic kidney disease

Background

Chronic kidney disease (CKD) is a worldwide public health problem. Recently urinary NGAL (uNGAL) has been proven to be a useful (potentially ideal) biomarker for early detection of CKD. The aim of the present study was to examine the correlation of uNGAL with severity of renal impairment in CKD and to evaluate its prognostic value in these subjects.

Methods

This was a prospective study carried out over a period of 24 months in subjects with CKD due to primary chronic glomerulonephritis. New cases of CKD stage II, III, IV aged between 18 and 65 years were enrolled as per KDIGO (Kidney Disease: Improving Global Outcomes) guidelines 2012. A total of 90 subjects completed the study up to the end-point. The primary follow-up end-point was 18 months, or decreased glomerular filtration rate of less than 15 mL/min. Secondary follow-up end-point was the number of subjects who expired during this period.

Results

Multiple regression model of estimated glomerular filtration rate showed significant associations with log uNGAL (β=0.38, P<0.001), Ca×PO4 (β=0.60, P<0.001), hemoglobin (β=0.37, P<0.001), urine protein (β=0.34, P<0.001), serum albumin (β=0.48, P<0.001), and systolic blood pressure (β=0.76, P<0.001). Receiver operator curve for uNGAL considering the progression of CKD showed area under the curve for uNGAL was 0.878 (95% confidence interval: 0.68–0.96). Cut-off value for uNGAL was log 3.5 unit with a sensitivity of 93.08% and specificity of 71.43% for predicting the progression of CKD. Kaplan–Meier survival curve showed that patients with log uNGAL levels <3.51 unit had a survival rate of 71.4% while patients with NGAL level >3.51 unit had a renal survival rate of 14.7%.

Conclusion

Our study result showed that uNGAL has a positive correlation with disease severity which signifies the prognostic importance of uNGAL in CKD.

Biomarkers of delayed graft function as a form of acute kidney injury in kidney transplantation

Renal transplantation ensures distinct advantages for patients with end-stage kidney disease. However, in some cases early complications can lead to allograft dysfunction and consequently graft loss. One of the most common early complications after kidney transplantation is delayed graft function (DGF). Unfortunately there is no effective treatment for DGF, however early diagnosis of DGF and therapeutic intervention (eg modification of immunosuppression) may improve outcome. Therefore, markers of acute kidney injury are required. Creatinine is a poor biomarker for kidney injury due principally to its inability to help diagnose early acute renal failure and complete inability to help differentiate among its various causes. Different urinary and serum proteins have been intensively investigated as possible biomarkers in this setting. There are promising candidate biomarkers with the ability to detect DGF. We focused on emerging biomarkers of DGF with NGAL is being the most studied followed by KIM-1, L-FABP, IL-18, and others. However, large randomized studies are needed to establish the value of new, promising biomarkers, in DGF diagnosis, prognosis and its cost-effectiveness.

Implications of the changes in serum neutrophil gelatinase-associated lipocalin and cystatin C in patients with chronic kidney disease

AIM

Early intervention in patients with chronic kidney disease (CKD) significantly improves the prognosis. The present widely used markers of renal function, such as serum creatinine (sCr), fail to reflect early renal damage and predict the progression of disease. The authors aimed to evaluate whether neutrophil gelatinase-associated lipocalin (NGAL), a novel specific biomarker of acute kidney injury, could predict the progression of CKD.

METHODS

We identified 92 patients with stage 2-4 CKD caused by primary chronic glomerulonephritis. The patients were followed for 2 years, the changes in NGAL levels in the progressive and non-progressive groups were compared.

RESULTS

First, the serum NGAL levels of patients with stage 2-4 CKD were significantly increased compared with the control group. Second, based on Pearson correlation analysis, positive correlations existed between NGAL and cystatin C levels and between NGAL and sCr levels. Third, bounded by the progress of renal function, the area under the curve of serum NGAL was 0.872 (95% confidence interval, 0.786-0.933), which suggests a blood NGAL cut-off level of 246 ng/mL (sensitivity 85.19%, specificity 81.54%). Fourth, Kaplan-Meier survival curve analysis showed that the serum NGAL level was closely related to the end-point of renal function in patients with CKD. Fifth, Cox multivariate regression analysis showed that the estimated glomerular filtration rate and blood NGAL are associated with progression of CKD.

CONCLUSION

Serum NGAL is an effective biomarker for detecting early-stage renal damage in CKD patients. Serum NGAL was significantly correlated with the severity of renal damage and the progression of renal function deterioration.

Assessment of neutrophil gelatinase-associated lipocalin in the brain-dead organ donor to predict immediate graft function in kidney recipients: a prospective, multicenter study

BACKGROUND

Delayed graft function is a major determinant of long-term renal allograft survival. Despite considerable efforts to improve donor selection and matching, incidence of delayed graft function remains close to 25%. As neutrophil gelatinase-associated lipocalin (NGAL) has been shown to predict acute renal failure, the authors tested the hypothesis that NGAL measurement in brain-dead donors predicts delayed graft function in kidney recipients.

METHODS

In a prospective, multicenter, observational study, serum NGAL was measured in donors at the time of transfer to operating room. The primary endpoint was the delayed graft function, defined as the need for renal replacement therapy during the first week posttransplantation.

RESULTS

Among 159 included brain-dead donors, 146 were analyzable leading to 243 renal transplantations. Of these, 56 (23%) needed renal replacement therapy. Donors' NGAL values were similar in case of both delayed and normal graft function in recipients. The area under the receiver-operating curve for NGAL to predict the need for renal replacement therapy before day 8 was 0.50 (95% CI, 0.42 to 0.59). The area under curve for NGAL to predict failure to return to a normal graft function at day 8 was 0.51 (95% CI, 0.44 to 0.59). Using multivariate analysis, NGAL was not associated to the need for renal replacement therapy (odds ratio, 0.99; 95% CI, 0.98 to1.00) or failure to return to a normal graft function at day 8 (odds ratio, 1.00; 95% CI, 0.99 to 1.00).

CONCLUSION

NGAL measurement in brain-dead donors at the time of recovery failed to predict delayed or normal graft function in kidney recipients.

Plasma neutrophil gelatinase-associated lipocalin and worsening renal function during everolimus therapy after heart transplantation

Recently, the mammalian target of rapamycin inhibitor everolimus (EVL) has been introduced as a novel immunosuppressant for heart transplant (HTx) recipients, and is expected to preserve renal function compared to conventional calcineurin inhibitors (CNIs). However, a considerable number of recipients treated with EVL were not free from worsening renal function regardless of CNI reduction. Data were collected retrospectively from 27 HTx recipients who had received EVL (trough concentration, 3.1-9.2 ng/mL) along with reduced CNIs (%decreases in trough concentration, 27.3 ± 13.0%) because of switching from mycophenolate mophetil due to digestive symptoms or neutropenia, progressive coronary artery vasculopathy, or persistent renal dysfunction, and had been followed over 1 year between August 2008 and January 2013. Estimated glomerular filtration rate (eGFR) decreased in 5 recipients (18.5%) during the study period. Univariate logistic regression analysis demonstrated that a higher plasma neutrophil gelatinase-associated lipocalin (P-NGAL) level was the only significant predictor for a decrease in eGFR over a 1-year EVL treatment period among all baseline parameters (P = 0.008). eGFR and proteinuria worsened almost exclusively in patients with baseline P-NGAL ≥ 85 ng/mL, which was the cutoff value calculated by an ROC analysis (area under the curve, 0.955; sensitivity, 1.000; specificity, 0.955). In conclusion, higher P-NGAL may be a novel predictor for the worsening of renal function after EVL treatment that is resistant to CNI reduction in HTx recipients.

Folate receptor alpha, mesothelin and megakaryocyte potentiating factor as potential serum markers of chronic kidney disease

Renal disease is the eighth leading cause of death in the United States. Early diagnosis is usually based on the detection of proteinuria or elevated serum creatinine, a relatively poor biomarker that does not accurately predict renal disease progression. As a result, more predictive biomarkers of renal function are sought. We present preliminary data on three protein biomarkers, folate receptor alpha (FRA), mesothelin (MSLN), and megakaryocyte potentiating factor (MPF), currently being pursued for applications in oncology diagnostics, and evaluate serum and urine levels in subjects with renal disease. Compared to healthy subjects, a significant (P < 0.0001) increase in all three biomarkers in both serum and urine of subjects with renal disease was demonstrated. Further, serum levels of these three protein biomarkers increased with increasing stage of disease suggesting their potential value in predicting progression in subjects with renal disease and raising caution in interpretation of data in oncology applications.

Serum anti-lipocalin 2 IgG is a novel biomarker in the diagnosis of systemic lupus erythematosus

BACKGROUND

Previous work suggests that lipocalin 2 is involved in the pathogenesis of systemic lupus erythematosus (SLE) and that this novel antigen could serve as a high-quality renal biomarker of acute kidney injury in SLE. However, serum lipocalin 2 antibody levels remain unclear. We have therefore undertaken this study to assess the level of serum IgG antibody against lipocalin 2 in different disease states and to evaluate the diagnostic value of this potential biomarker in SLE.

METHODS

Serum levels of anti-lipocalin IgG antibodies were measured by ELISA in 103 SLE patients, 93 rheumatoid arthritis (RA) patients, 29 primary Sjögren's syndrome (pSS) patients, 13 systemic sclerosis (SSc) patients, and 91 healthy controls. Diagnostic properties of anti-lipocalin IgG were determined by receiver-operating characteristic (ROC) curve analysis.

RESULTS

The level of serum anti-lipocalin IgG in patients with SLE was significantly higher than in patients with RA, pSS, SSc, or healthy controls (p < 0.05), effectively distinguishing SLE from other conditions with high sensitivity and specificity (49.5% and 90.7%, respectively). In ROC curve analysis, the area under the curve (AUC) is 0.783, with a 95% confidence interval (CI) extending from 0.729 to 0.839. Anti-lipocalin antibodies were present in 48.1% of anti-Sm-negative SLE patients, and also occurred in SLE patients lacking anti-dsDNA (52%) or anti-nucleosome antibodies (46.3%) antibodies. Finally, SLE patients with positive anti-lipocalin IgG possessed higher levels of IgA and CRP than the negative group (p < 0.05), clearly demonstrating a positive correlation between anti-lipocalin IgG and these laboratory parameters.

CONCLUSIONS

Anti-lipocalin 2 IgG is a promising biomarker for the diagnosis of SLE, particularly when obtained in conjunction with anti-Sm, anti-dsDNA, and anti-nucleosome antibody levels.

The extracellular matrix in the kidney: a source of novel non-invasive biomarkers of kidney fibrosis?

Interstitial fibrosis is the common endpoint of end-stage chronic kidney disease (CKD) leading to kidney failure. The clinical course of many renal diseases, and thereby of CKD, is highly variable. One of the major challenges in deciding which treatment approach is best suited for a patient but also in the development of new treatments is the lack of markers able to identify and stratify patients with stable versus progressive disease. At the moment renal biopsy is the only means of diagnosing renal interstitial fibrosis. Novel biomarkers should improve diagnosis of a disease, estimate its prognosis and assess the response to treatment, all in a non-invasive manner. Existing markers of CKD do not fully and specifically address these requirements and in particular do not specifically reflect renal fibrosis. The aim of this review is to give an insight of the involvement of the extracellular matrix (ECM) proteins in kidney diseases and as a source of potential novel biomarkers of renal fibrosis. In particular the use of the protein fingerprint technology, that identifies neo-epitopes of ECM proteins generated by proteolytic cleavage by proteases or other post-translational modifications, might identify such novel biomarkers of renal fibrosis.

The role of vitamin D in regulating the iron-hepcidin-ferroportin axis in monocytes

Chronic kidney disease affects 40% of adults aged 65 and older. Anemia of CKD is present in 30% of patients with CKD and is associated with increased cardiovascular risk, decreased quality of life, and increased mortality. Hepcidin-25 (hepcidin), the key iron regulating hormone, prevents iron egress from macrophages and thus prevents normal recycling of the iron needed to support erythropoiesis. Hepcidin levels are increased in adults and children with CKD. Vitamin D insufficiency is highly prevalent in CKD and is associated with erythropoietin hyporesponsiveness. Recently, hepcidin levels were found to be inversely correlated with vitamin D status in CKD. The aim of this study was to investigate the role of vitamin D in the regulation of hepcidin expression in vitro and in vivo. This study reports that 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), the hormonally active form of vitamin D, is associated with decreased hepcidin and increased ferroportin expression in lipopolysaccharide (LPS) stimulated THP-1 cells. 1,25(OH)₂D₃ also resulted in a dose-dependent decrease in pro-hepcidin cytokines, IL-6 and IL-1β, release in vitro. Further, we show that high-dose vitamin D therapy impacts systemic hepcidin levels in subjects with early stage CKD. These data suggest that improvement in vitamin D status is associated with lower systemic concentrations of hepcidin in subjects with CKD. In conclusion, vitamin D regulates the hepcidin-ferroportin axis in macrophages which may facilitate iron egress. Improvement in vitamin D status in patients with CKD may reduce systemic hepcidin levels and may ameliorate anemia of CKD.

Neutrophil gelatinase associated lipocalin in acute kidney injury

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a member of the lipocalin family of proteins. Usually, NGAL is produced and secreted by kidney tubule cells at low levels, but the amount produced and secreted into the urine and serum increases dramatically after ischemic, septic, or nephrotoxic injury of the kidneys. The purpose of our review article is to summarize the role of NGAL in acute kidney injury (AKI), emergent, and intensive care.

METHODS

A PubMed search was performed (only English-language articles concerning human subjects were considered) using each of the following search term combinations: neutrophil gelatinase-associated lipocalin OR NGAL and acute kidney injury OR AKI; cardiac surgery; heart failure OR cardiology; intensive care; emergency department OR emergency medicine; nephropathy OR nephrotoxicity and transplantation.

RESULTS

The results of our search yielded 339 articles. Of the 339 articles, 160 were eligible for review based on the predefined criteria for inclusion.

CONCLUSION

Based on the evidence reviewed, it is clear that patient NGAL level is an appropriate, sensitive, and specific early biomarker of AKI caused by a variety of different etiologies. It is advised that a multidisciplinary group of experts come together to make recommendations and propose a consensus of clinical procedures to advance the most efficacious NGAL monitoring protocol for early detection and treatment of patients with AKI.

Neutrophil gelatinase-associated lipocalin in kidney transplantation is an early marker of graft dysfunction and is associated with one-year renal function

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been suggested as potential early marker of delayed graft function (DGF) following kidney transplantation (KTx). We conducted a prospective study in 40 consecutive KTx recipients to evaluate serial changes of uNGAL within the first week after KTx and assess its performance in predicting DGF (dialysis requirement during initial posttransplant week) and graft function throughout first year. Urine samples were collected on post-KTx days 0, 1, 2, 4, and 7. Linear mixed and multivariable regression models, receiver-operating characteristic (ROC), and areas under ROC curves were used. At all-time points, mean uNGAL levels were significantly higher in patients developing DGF (n = 18). Shortly after KTx (3–6 h), uNGAL values were higher in DGF recipients (on average +242 ng/mL, considering mean dialysis time of 4.1 years) and rose further in following days, contrasting with prompt function recipients. Day-1 uNGAL levels accurately predicted DGF (AUC-ROC = 0.93), with a performance higher than serum creatinine (AUC-ROC = 0.76), and similar to cystatin C (AUC-ROC = 0.95). Multivariable analyses revealed that uNGAL levels at days 4 and 7 were strongly associated with one-year serum creatinine. Urinary NGAL is an early marker of graft injury and is independently associated with dialysis requirement within one week after KTx and one-year graft function.

Urine neutrophil gelatinase-associated lipocalin levels do not improve risk prediction of progressive chronic kidney disease

Novel biomarkers may improve our ability to predict which patients with chronic kidney disease (CKD) are at higher risk for progressive loss of renal function. Here, we assessed the performance of urine neutrophil gelatinase-associated lipocalin (NGAL) for outcome prediction in a diverse cohort of 3386 patients with CKD in the Chronic Renal Insufficiency Cohort study. In this cohort, the baseline mean estimated glomerular filtration rate (eGFR) was 42.4 ml/min per 1.73 m(2), the median 24-h urine protein was 0.2 g/day, and the median urine NGAL concentration was 17.2 ng/ml. Over an average follow-up of 3.2 years, there were 689 cases in which the eGFR was decreased by half or incident end-stage renal disease developed. Even after accounting for eGFR, proteinuria, and other known CKD progression risk factors, urine NGAL remained a significant independent risk factor (Cox model hazard ratio 1.70 highest to lowest quartile). The association between baseline urine NGAL levels and risk of CKD progression was strongest in the first 2 years of biomarker measurement. Within this time frame, adding urine NGAL to a model that included eGFR, proteinuria, and other CKD progression risk factors led to net reclassification improvement of 24.7%, but the C-statistic remained nearly identical. Thus, while urine NGAL was an independent risk factor of progression among patients with established CKD of diverse etiology, it did not substantially improve prediction of outcome events.

Protein and peptide biomarkers in organ transplantation

Organ transplantation is the optimal treatment choice for end-stage organ failure in pediatric patients. The ideal maintenance of a transplanted organ requires efficient monitoring tools and an effective individualized post-transplant treatment plan. Currently available post-transplant monitoring options are not ideal because of their invasiveness or their lack of sensitivity and specificity when providing an accurate assessment of transplant injury. Current research on proteins and peptides, including mass spectrometry-based proteomics, can identify novel surrogate protein and peptide biomarkers that can assist in monitoring the graft in order to correctly assess the status of the transplanted organ. In this article, we have critically reviewed current relevant literature to highlight the importance of protein and peptide biomarkers in the field of pediatric organ transplantation, the status of research findings in the field of protein and peptide biomarkers in different organ transplantation and factors that impact and inhibit the progression of protein biomarker discovery in the field of solid-organ transplantation in pediatrics.

Kidney Injury Biomarkers in Hypertensive, Diabetic, and Nephropathy Rat Models Treated with Contrast Media

Contrast-induced nephropathy (CIN) refers to a decline in renal function following exposure to iodinated contrast media (CM). The present study was initiated to explore the role of known human risk factors (spontaneous hypertension, diabetes, protein-losing nephropathy) on CIN development in rodent models and to determine the effect of CM administration on kidney injury biomarkers in the face of preexisting kidney injury. Spontaneously hypertensive rats (hypertension), streptozotocin-treated Sprague Dawley rats (diabetes), and Dahl salt-sensitive rats (protein-losing nephropathy) were given single intravenous injections of the nonionic, low osmolar contrast medium, iohexol. Blood urea nitrogen (BUN), serum creatinine (sCr), and urinary biomarkers; albumin, lipocalin 2 (Lcn-2), osteopontin (Opn), kidney injury molecule 1 (Kim-1), renal papillary antigen 1 (Rpa-1), α-glutathione S-transferase (α-Gst), µ-glutathione S-transferase (µ-Gst), and beta-2 microglobulin (β2m) were measured in disease models and appropriate controls to determine the response of these biomarkers to CM administration. Each disease model produced elevated biomarkers of kidney injury without CM. Preexisting histopathology was exacerbated by CM but little or no significant increases in biomarkers were observed. When 1.5-fold or greater sCr increases from pre-CM were used to define true positives, receiver–operating characteristic curve analysis of biomarker performance showed sCr was the best predictor of CIN across disease models. β2m, Lcn-2, and BUN were the best predictors of histopathology defined kidney injury.

Assessment and diagnosis of renal dysfunction in the ICU

Identifying patients with impaired renal function is crucial in the setting of critical illness. Serum creatinine serves as the gold standard for assessing steady-state renal function, helping to define those with chronic kidney disease (CKD). Although these baseline creatinine values are often not available in the setting of critical illness, CKD, whether defined by serum creatinine or proteinuria, increases the risk of developing acute kidney injury (AKI). Despite delays in elevations following renal insults, serum creatinine remains the standard for assessing acute changes in renal function. Standardized definitions of AKI, using changes in serum creatinine and urine output, have informed the epidemiology of ICU-acquired AKI and have helped define the long-term outcomes in patients who experience AKI. A complex cyclical interplay exists between AKI and CKD, in which CKD predisposes patients to an increased risk of AKI, whereas those with AKI, regardless of baseline renal function, are more likely to suffer from post-AKI CKD. The clarification of the AKI-CKD dynamic remains a work in progress and will be aided by the implementation of novel measures of renal function. Several novel biomarkers of renal function have been proposed to augment serum creatinine in the diagnosis of AKI and CKD. These biomarkers, taken with recent clinical investigations, have laid the groundwork for the impending paradigm shift in risk stratifying and in diagnosing changes in renal function in the ICU.

Epithelial-mesenchymal crosstalk alteration in kidney fibrosis

The incidence of chronic kidney diseases (CKD) is constantly rising, reaching epidemic proportions in the western world and leading to an enormous threat, even to modern health-care systems, in industrialized countries. Therapies of CKD have greatly improved following the introduction of drugs targeting the renin-angiotensin system (RAAS) but even this refined pharmacological approach has failed to stop progression to end-stage renal disease (ESRD) in many individuals. In vitro historical data and recent new findings have suggested that progression of renal fibrosis might occur as a result of an altered tubulo-interstitial microenvironment and, more specifically, as a result of an altered epithelial-mesenchymal crosstalk. Here we the review biological findings that support the hypothesis of an altered cellular crosstalk in an injured local tubulo-interstitial microenvironment leading to renal disease progression. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Progressive Increase of Inflammatory Biomarkers in Chronic Kidney Disease and End-Stage Renal Disease

Chronic kidney disease (CKD) has reached epidemic levels. It is a multisystem disease associated with elevated systemic inflammatory and hypercoagulable states. Most concerning are the cardiovascular risks associated with all stages of kidney disease. It is difficult to assess kidney disease stage progression and cardiovascular risk with current indicators such as estimated glomerular filtration rate and conventional cardiovascular risk factors. However, the use of biomarkers to assess the underlying pathological disease state may bridge the gap. This study evaluated biomarkers of inflammation including C-reactive protein, d-dimer, neuron-specific enolase, neutrophil gelatinase–associated lipocalin, tumor necrosis factor receptor I, and thrombomodulin in 3 groups of patients: CKD stages 2-4, end-stage renal disease (ESRD), and age-matched controls. The study demonstrated a statistically significant progressive upregulation in mean concentration of all markers when comparing controls to CKD and ESRD. Therefore, biomarkers may be able to evaluate the inflammatory state in kidney disease and potentially predict the cardiovascular risk.