Urinary Neutrophil Gelatinase-associated Lipocalin Levels Research Articles

Urine Neutrophil Gelatinase-Associated Lipocalin Determination as a Donor Auxiliary Examination Method — First Results

A growing lack of donor organs has caused extension of criteria for deceased donation. Therefore, elderly donors and donors with increased serum creatinine levels, as well as donors after cardiocirculatory death, have become used more frequently. The examination of such donors is strongly limited due to the lack of time, and the determination of the quality of donor organs is still based on clinical and laboratory screening data of donors. Implementation of new examination methods is required to determine the functional condition of donor organs more accurately, which would allow correct selection of donors. This retrospective study included all consecutive deceased donor (DD) kidney transplantations (KTx) performed in a single centre during the period from 1 January 2010 till 30 November 2011. The donor examination was supplemented by the urine neutrophil gelatinase-associated lipocalin (U-NGAL) test. Recipients were available for follow- up for at least 12 months (totally 97 KTx from 63 DD). All cases were divided into four groups according to U-NGAL and serum creatinine (S-Crea) levels in donors: group I - normal U-NGAL and S-Crea (n = 70); group II - elevated U-NGAL and S-Crea (n = 10); group III - elevated U-NGAL and normal S-Crea (n = 9); group IV - normal U-NGAL and elevated S-Crea (n = 8). Information about rates of delayed graft function (DGF) and immediate graft function (IGF), acute rejection (AR), recipient S-Crea levels during the first post-transplant year for functioning grafts, graft losses and recipient deaths were summarised. Donor urine NGAL level showed moderate correlation with donor S-creatinie level (r = 0.543, P < 0.001). DGF was observed in 20 recipients (21%) and demonstrated association with increased donor S-creatinine (0.135 ± 0.061 vs. 0.108 ± 0.04 mmol/l in IGF, p < 0.05). Combination of increased donor S-Crea and U-NGAL (group II) was associated with worse graft function during the first year after transplantation. Recipients in group III had increased S-Crea at the time of discharge from hospital and at one year after transplantation. One-year death censored graft survival and recipient survival was similar in all groups (P = NS). Determination of U-NGAL can be used as a donor auxiliary examination method for determination of the kidney graft functional condition and for prediction of post-transplant results. The study needs to be continued with a higher number of observations and longer post-transplant follow-up.

Urinary Tubular Protein-Based Biomarkers in the Rodent Model of Cisplatin Nephrotoxicity

BackgroundSeveral biomarkers are becoming available for the early detection of acute kidney injury (AKI), but few have been directly compared.ObjectiveTo compare urinary kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL),...

Early Diagnosis of Acute Kidney Injury during Open Heart Surgery under Extracorporeal Circulation

Objective: to analyze the informative value of new methods for the early diagnosis of acute kidney injury (AKI) to determine treatment policy after heart surgery under extracorporeal circulation (EC). Subjects and methods. Patients of both sexes were examined before and after heart surgery under EC. A perfusion index of 2.5±0.4 l/min/m2, moderate hypothermia, and a mean blood pressure of 60—100 mm Hg were maintained throughout EC. Urine samples were taken 4—6 and 16—18 hours after termination of EC and centrifuged. Urinary neutrophil gelatinase associated lipocalin (NGAL) was determined using an Abbott Architect i1000sr analyzer. The cutoff level proposed by the Abbott Diagnostics was 132 ng/ml. NonResults. Two groups were formed. Group 1 included 14 patients with AKI according to the 2004 RIFLE classification. Stage 1 AKI was seen in 5 cases; there was no disease progression or urinary NGAL elevation. Four to six hours after EC, 8 of 9 patients with Stages 2—3 AKI had a urinary NGAL level of 200 ng/ml. Two patients required renal replacement therapy (RRT), their renal function recovery was observed. Other two patients died from respiratory and cardiac failure. Group 2 comprised 61 patients without AKI: in 59 and 2 patients, urinary NGAL levels were lower and higher than the accepted cutoff levels, respectively. No deaths were observed. AKI developed in patients who had more prolonged EC, transverse aortic ligation, low hemoglobin levels and received more doses of donor blood. In Stages 1—3 AKI, the sensitivity was 57.1% (95% confidence interval (CI), 28.9—82.2) and specificity was 96.7% (95% CI, 88.6—99.5); in Stages 2—3 AKI, these were 88.9% (95% CI, 51.7—98.2) and 97% (95% CI, 89.5—99.5), respectively. Conclusion. Urinary NGAL levels should be determined by using the laboratory platforms 4—6 hours after long EC, as well as aortic ligation, and transfusion of two or more blood doses. Elevated urinary NGAL levels are highly sensitive to Stages 2—3 AKI and useful in assessing indications by the beginning of RRT. Key words: cardiac surgery under extracorporeal circulation, acute kidney injury, urinary NGAL, urinary albumin to creatinine ratio.

Urine Neutrophil Gelatinase-Associated Lipocalin as a Marker of Acute Kidney Injury After Kidney Surgery

We evaluated urine NGAL as a marker of acute kidney injury in patients undergoing partial nephrectomy. We sought to identify the preoperative clinical features and surgical factors during partial nephrectomy that are associated with renal injury, as measured by increased urine NGAL vs controls. Using patients treated with radical nephrectomy or thoracic surgery as controls, we prospectively collected and analyzed urine and serum samples from patients treated with partial or radical nephrectomy, or thoracic surgery between April 2010 and April 2012. Urine was collected preoperatively and at multiple time points postoperatively. Differences in urine NGAL levels were analyzed among the 3 surgical groups using a generalized estimating equation model. The partial nephrectomy group was subdivided based on a preoperative estimated glomerular filtration rate of less than 60, or 60 ml/minute/1.73 m(2) or greater. Of 162 patients included in final analysis more than 65% had cardiovascular disease. The median estimated glomerular filtration rate was greater than 60 ml/minute/1.73 m(2) in the radical and partial nephrectomy, and thoracic surgery groups (61, 78 and 84.5 ml/minute/1.73 m(2), respectively). Preoperatively, a 10 unit increase in the estimated glomerular filtration rate was associated with a 4 unit decrease in urine NGAL in the partial nephrectomy group. Postoperatively, urine NGAL in the partial nephrectomy group was not higher than in controls and did not correlate with ischemia time. Patients with partial nephrectomy with a preoperative estimated glomerular filtration rate of less than 60 ml/minute/1.73 m(2) had higher urine NGAL postoperatively than those with a higher preoperative estimated rate. Urine NGAL does not appear to be a useful marker for detecting renal injury in healthy patients treated with partial nephrectomy. However, patients with poorer preoperative renal function have higher baseline urine levels and appear more susceptible to acute kidney injury, as detected by urine levels and Acute Kidney Injury Network criteria, than those with a normal estimated glomerular filtration rate.

Urinary neutrophil gelatinase-associated lipocalin levels predict cisplatin-induced acute kidney injury better than albuminuria or urinary cystatin C levels

Cisplatin-induced acute kidney injury (AKI) is a major concern among clinicians in prescribing cisplatin-based chemotherapy. This study evaluated and compared the ability of urinary biomarkers, including urinary neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and the urinary albumin to creatinine ratio (ACR) to predict cisplatin-induced AKI. Thirty-three cancer patients receiving cisplatin-based chemotherapy were prospectively studied, including 10 (30%) who developed AKI (the study group). Changes of urinary biomarkers were compared at 4 hours, 8 hours, and 12 hours, and 1 day, 2 days, 3 days, and 4 days after cisplatin intravenous infusions (75mg/m2) versus the baseline. There was a significant increase in urinary NGAL levels from 12 hours to 4 days (p<0.05) compared to baseline after cisplatin infusion in the AKI group. The magnitude of these changes over time differed significantly by group (p<0.001). The area under the receiver operating curve describing the relationship between urinary NGAL levels and AKI within 12 hours was 0.865 (95% confidence interval=0.691–1.000). Urinary NGAL levels independently predicted AKI 12 hours after cisplatin (p=0.045) after adjustments for age, gender, body mass index, baseline serum creatinine, and urinary total protein. Urinary NGAL levels may be an early biomarker of AKI in patients receiving cisplatin-based treatment.

Urinary Biomarkers for The Prediction of Reversibility in Acute-on-Chronic Renal Failure

There is no reliable clinical test to predict the reversibility of acute-on-chronic renal failure. We study whether urinary biomarkers could be used as a noninvasive prognostic marker in patients with acute-on-chronic renal failure. We studied 39 adult patients with pre-existing chronic renal impairment presenting to us with acute-on-chronic renal failure. Urinary neutrophil gelatinase-associated lipocalin (NGAL) level was measured. The mRNA of kidney injury molecule-1 (KIM-1), interleukin-18 (IL-18), alpha-1-microglobulin (α1M), sodium/hydrogen exchanger-3 (NHE3), beta-2 microglobulin (β2M), and N-acetyl-β-D-glucosaminidase (NAG) in urinary sediment were quantified. Urinary NGAL level significantly correlated with the serum creatinine at presentation (r=0.762, p<0.0001) but not baseline serum creatinine. Urinary sediment β2M expression significantly correlated with baseline glomerular filtration rate (GFR) (r=−0.400, p=0.012). Urinary α1M and NHE3 expressions were significantly higher in ischemic acute tubular necrosis than other causes of acute kidney injury (p<0.0001 and p=0.006, respectively). Urinary α1M expression significantly correlated with the degree of improvement in renal function (r=0.387, p=0.026), as well as the estimated GFR 6 months later (r=0.386, p=0.027). In patients with acute-on-chronic renal failure, urinary NGAL level correlates with the severity of renal failure, while urinary α1M expression correlates with the degree of renal function recovery. Quantification of urinary α1M mRNA may be developed as an non-invasive tool for risk stratification of this group of patients.

Manyetik Rezonans Görüntüleme ve Bilgisayarlı Tomografi Yöntemlerinin İdrarda Nötrofil Jelatinaz ile İlişkili Lipokalin Düzeylerine Etkisi

a Objective: Urinary neutrophil gelatinase associated lipocalin (NGAL) is among novel markers assessed for early diagnosis of acute kidney injury. The effect of gadolinium-based contrast media on urinary NGAL concentrations has not been studied before. The aim of our study was to compare the effect of iodinated contrast agents and gadolinium-based contrast media on renal function and on urinary NGAL levels in patients with normal renal function. Material and Methods: The study group consisted of 40 patients. They were selected among patients who would undergo computerized tomography (CT) (n=20) or magnetic resonance imaging (MRI) (n = 20) scan. Patients with diabetes, malignancy or infection were excluded. Blood samples were drawn before, and 2 and 48 h after the procedure. Urine samples were collected before and 2 h after the procedure for NGAL measurements. Levels of urinary NGAL and blood creatinine before and after the procedure were compared. Results: Urinary NGAL levels did not significantly change 2 h after the procedure compared to baseline value at CT [29 (4.1 - 499) vs. 26.7 (1 - 113) ng/ml, p=0.100] and at MRI [16 (6.7 - 169) vs. 15.7 (3.5- 112) ng/ml, p=0.313]. Although creatinine levels at 48 h were higher compared to baseline levels, they did not increase up to 50% in the CT group. The serum creatinine did not change at any time point in the MRI group. Conclusion: Gadolinium or iodinated contrast agents did not significantly change urinary NGAL levels when used intravenously in patients with normal renal function.

Urine Catalytic Iron and Neutrophil Gelatinase-Associated Lipocalin as Companion Early Markers of Acute Kidney Injury after Cardiac Surgery: A Prospective Pilot Study

Background: Open heart surgery with cardiopulmonary bypass is recognized as a common cause of acute kidney injury (AKI). The conventional biomarker creatinine is not sensitive enough to detect AKI until a significant decline in renal filtration has occurred. Urine neutrophil gelatinase-associated lipocalin (NGAL), part of an acute response to the release of tissue iron from cells, is an early biomarker and a predictor of AKI in a variety of clinical settings. We sought to evaluate the relationship between urine catalytic iron (unbound iron) and NGAL over the course of AKI due to cardiac surgery. Methods: Fourteen patients who underwent open heart surgery had the following measured: serum creatinine (0, 12, 24, 48 and 72 h postoperatively), urine NGAL and urine catalytic iron (0, 8, 24 and 48 h postoperatively). Urine NGAL and urine catalytic iron were quantified by immunoassay and bleomycin-detectable iron assay, respectively. AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. Results: Urine catalytic iron increased significantly (p < 0.05) within 8 h and peaked at 24 h postoperatively in patients who developed AKI (n = 8, baseline 101.96 ± 177.48, peak 226.35 ± 238.23 nmol/l, p = 0.006), but not in non-AKI patients (n = 6, baseline 131.08 ± 116.21, peak 163.99 ± 109.62 nmol/l, p = 0.380). Urine NGAL levels also peaked at 24 h with significant increase observed only in AKI patients: AKI – baseline 34.88 ± 26.47, peak 65.50 ± 27.03 ng/ml, p = 0.043; non-AKI – baseline 59.33 ± 31.72, peak 71.00 ± 31.76 ng/ml, p = 0.100. The correlation between baseline levels of urine catalytic iron and NGAL and peak levels of urine catalytic iron and NGAL was r = 0.86, p < 0.0001. Conclusion: Urine catalytic iron appears to rise and fall in concert with NGAL in patients undergoing cardiac surgery and may be indicative of early AKI. Future research into the role that catalytic iron plays in acute organ injury syndromes and its potential diagnostic and therapeutic implications is warranted.

Urinary Neutrophil Gelatinase Associated Lipocalin (NGAL) for Early Diagnosis of Acute Kidney Injury in Renal Transplant Recipients

BackgroundEarly predictive biomarkers for acute kidney injury (AKI) such as neutrophil elatinase-associated lipocalin (NGAL) could identify patients who may benefit from early initiation of treatment.ObjectivesWe aimed to obtain a cut off point for AKI prediction by urine NGAL in kidney transplantation.Patients and MethodsIn a prospective cohort study, 64 adult who underwent kidney transplantation from living or deceased donors at Baqiyatallah transplant center between April 2009 and January 2010 were included. Patients divided into two groups based on the presence or absence of graft dysfunction. In this study, early graft dysfunction (post transplantation AKI) was defined as Cr level more than 1.5 mg/dL on the second postoperative day.ResultsPost-transplant AKI was observed in 31 recipients. Mean urinary NGAL level was greater in recipients with AKI (P = 0.024). In linear regression model, AKI was only factor affected on urinary NGAL level (B = 299.8, P = 0.009). The best sensitivity and specificity for AKI detection by urinary NGAL observed at 2 hour after operation with cut-off point 204 ng/mL.ConclusionsOur study showed in those who developed early post transplantation graft dysfunction the best AUC-ROC for urine NGAL observed at a cut-off value of 204 ng/mL after 2 hour post transplantation.

Neutrophil gelatinase-associated lipocalin as an early marker of acute kidney injury in patients with traumatic brain injury

Recent studies have shown that urinary neutrophil gelatinase-associated lipocalin (NGAL) is rapidly up-regulated early after murine renal injury, and in patients after cardiac surgery or patients critically ill with multiple trauma. In this study, we evaluated urinary NGAL levels as a potential biomarker of early acute kidney injury (AKI) in patients with severe traumatic brain injury (TBI). All patients with severe TBI admitted to our neurosurgical intensive care unit from March to September 2011 were enrolled prospectively. Urinary NGAL was measured using a chemiluminescent microparticle immunoassay upon admission and at 24 and 48 hours after TBI. The presence of AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. Using AKIN criteria, a total of 13 patients were identified with AKI, an incidence of 24%. Those who subsequently developed AKI had a striking rise in urinary NGAL early after TBI and a sustained increase over the entire duration of the study. The urinary NGAL level of the AKI group was significantly higher than the group without AKI at all time points. Using a cutoff value of 53.9 ng/mL, the area under the receiver-operating characteristic curve for urinary NGAL at 48 hours was 0.876 with a sensitivity of 0.69 and specificity of 0.95. Increased urinary NGAL is associated with an increased occurrence of AKI in patients with severe TBI. It is possible that urinary NGAL could provide a screening tool for AKI immediately after severe TBI, and this may in turn allow early intervention to ameliorate the adverse effects of AKI.

Urinary neutrophil gelatinase-associated lipocalin as a biomarker for the diagnosis of hepatorenal syndrome in cirrhotic patients

PurposeThe aim of the study was to assess the usefulness of urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a biomarker for hepatorenal syndrome (HRS) in patients with cirrhosis.Patients and methodsEighty-two cirrhotic patients were enrolled in this study. Urinary levels of NGAL were measured using enzyme-linked immunosorbent assay. Ten normal healthy individuals were enrolled as a control group. Group I included 15 cirrhotic patients with normal kidney function. Group II included 52 cirrhotic patients with acute impaired kidney function: 21 with prerenal azotemia, 22 with HRS, and nine with intrinsic acute kidney injury (iAKI). Group III included 15 cirrhotic patients with chronic impaired kidney function. Group IV included 10 healthy normal individuals as control.ResultsIn HRS, uNGAL was significantly different from patients with either iAKI or prerenal azotemia. uNGAL levels in patients with prerenal azotemia were low and equivalent to levels in patients with normal kidney function and chronic kidney disease. uNGAL elevation was more prominent in type 1 than in type 2. Serum creatinine was significantly higher in patients with iAKI compared with those with normal kidney function and chronic kidney disease but was statistically similar to those with prerenal azotemia and HRS. Patients with HRS had a significantly higher level of serum creatinine than those with prerenal azotemia, but the level was similar to patients with iAKI. Fractional excretion of sodium was significantly higher in patients with iAKI than in patients with either HRS or prerenal azotemia.ConclusionuNGAL levels may be useful in the differential diagnosis of HRS from other causes of acute impairment of kidney function in cirrhosis.

Evaluation of the diagnostic performance of new markers for acute kidney injury associated with contrast administration

Background: Contrast-induced nephropathy (CIN) is a form of acute kidney injury (AKI) that is caused by exposure to contrast media in diagnostic imaging and interventional procedures such as angiography. At present serum creatinine is the only standard test for it. A few studies have been published analyzing the potential use of neutrophil-gelatinase-associated lipocalin (NGAL) in AKI. Aim: The aim of this study is to search for new markers to identify AKI acute renal failure earlier than serum creatinine. Materials and Methods: We studied 100 consecutive patients with normal serum creatinine undergoing angiographic procedure against Urine NGAL, serum NGAL, serum Cystatin C and urinary interleukin-18 (IL-18) at basal, and 2 h, 4 h, 8 h, 24 h, and 48 h after the angiography. Results: There was a significant rise in serum NGAL levels at 2 h, 4 h, and 8 h after angiography and in urinary NGAL levels at 4 h, 8 h, and 24 h after the procedure. Cystatin C rose significantly at 8 h and 24 h after the procedure, On the other hand, there was mild rise in urinary Il-18 levels at 24 h, but not significant. The presence of CIN associated with AKI was 13%. Conclusion: The present study highlighted the importance of serum NGAL, urine NGAL and Cystatin C in detecting AKI associated with contrast administration earlier than serum creatinine.

Urinary L-FABP and its combination with urinary NGAL in early diagnosis of acute kidney injury after cardiac surgery in adult patients

Background/Aim: The early detection of acute kidney injury (AKI) may be become possible by several promising early biomarkers which may facilitate the early detection, differentiation and prognosis prediction of AKI. In this study, we investigated the value of urinary liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL) and their combination in predicting the occurrence and the severity of AKI following cardiac surgery.Methods: We prospectively followed 109 patients undergoing open heart surgery and identified 26 that developed AKI, defined as an increase in serum creatinine of ≥0.3 mg/dl or ≥150% of baseline creatinine. Serum creatinine (SCr), urinary L-FABP, and NGAL corrected by urine creatinine were tested pre-operation, at 0 hour and 2 hours post-operation. Each marker was assessed at each time point between patients with and without AKI. Receiver operating characteristic (ROC) curves and area under curves (AUC) were used to evaluate the diagnostic accuracy of urinary L-FABP, NGAL and their combination for predicting AKI.Results: Patients were aged 63.0 ± 11.3 years, 66.1% were male and baseline SCr was 70.5 ± 19.1 umol/L. Of 109 patients, 26(23.9%) developed AKI (AKIN stage I, II and III were 46.2%, 34.6% and 19.2% separately). The levels of urinary L-FABP and NGAL were significantly higher in AKI patients than non-AKI patients at 0 hour and 2 hours postoperative. AUCs for L-FABP was 0.844 (sensitivity (ST) 0.846, specificity (SP) 0.819, cut-off (CO) 2226.50 μg/g Ucr) at 0 hours and 0.832 at 2 hours (ST 0.808, SP 0.747, CO 673.09 μg/g Ucr) while 0.866 for NGAL at 0 hours (ST 0.769, SP 0.819, CO 131.12 μg/g Ucr) and 0.871 at 2 hours (ST 0.808, SP 0.831, CO 33.73 μg/g Ucr) to predict AKI occurrence. Using a combination of L-FABP and NGAL analyzed at the same timepoint as above, we were able to obtain an AUC of 0.911–0.927, p < 0.001. Similar AUCs of 0.81–0.87 were found to predict AKI stage II–III.Conclusions: Urinary L-FABP and NGAL increased at an early stage after cardiac surgery. The combination of the two biomarkers enhanced the accuracy of the early detection of postoperative AKI after cardiac surgery before a rise in SCr.

Neutrophil gelatinase-associated lipocalin is a sensitive biomarker for the early diagnosis of acute rejection after living-donor kidney transplantation

Early diagnosis of kidney allograft dysfunction is crucial for the management and long-term survival of transplanted kidneys. We investigated whether neutrophil gelatinase-associated lipocalin (NGAL), interleukin 18 (IL-18), and liver-type fatty acid-binding protein (L-FABP) are capable of being used as novel biomarkers of acute kidney allograft dysfunction. We measured serum and urine NGAL, urine IL-18, and urine L-FABP levels on the first 3 days after transplantation. To assess the diagnostic sensitivity of these biomarkers, a receiver-operating characteristic curve (ROC) was plotted, and the area under the curve (AUC) was calculated to quantify the accuracy of the parameter. Sections from paraffin-embedded biopsy specimens were examined by immunohistochemistry for NGAL expression. Twelve cases were clinically diagnosed as acute rejection (AR) by renal biopsy. Urine NGAL was the most sensitive of these markers for detection of acute kidney allograft dysfunction. The cutoff value of urine NGAL was 66.0 ng/ml, with an AUC of 0.79 (95 % CI 0.68-0.88). Sensitivity of serum NGAL was about the same as urine NGAL with an AUC of 0.75 (0.64-0.85). IL-18 and L-FABP were 0.584 (95 % CI 0.433-0.725) and 0.612 (95 % CI 0.460-0.749), respectively. NGAL was more useful than other biomarkers to detect AR of kidney allograft dysfunction. NGAL staining intensity was significantly increased in the proximal tubules of the transplants with AR than in transplants that were not acutely rejected. Urine NGAL level was found to be the most sensitive biomarker of acute kidney allograft dysfunction after living-donor kidney transplantation.

Tubular Damage Is Ubiquitous in Newly-Diagnosed Patients with Multiple Myeloma: Comparison of Three Urinary and Two Serum Markers of Kidney Injury.

Abstract 2919Renal impairment is a common complication of multiple myeloma (MM). The CRAB criteria define the serum creatinine (sCr) level of >2 mg/dl as the cut-off value for starting therapy in MM patients. However, the measurement of sCr for the evaluation of renal impairment has several limitations. Furthermore, the estimation of glomerular filtration rate (GFR) by the MDRD equation has greater value in patients with stabilized sCr, while the majority of MM patients have acute renal damage, which may be irreversible. Thus, identification of individuals at higher risk of early kidney dysfunction is critical to the timely initiation of treatment to prevent permanent renal damage. For this reason, several markers of renal dysfunction have been used in renal disorders. Neutrophil gelatinase-associated lipocalin (NGAL) is a protein overproduced by proximal tubular cells in response to kidney injury, while kidney injury molecule-1 (KIM-1) is a type 1 transmembrane glycoprotein that is overexpressed in dedifferentiated proximal tubule epithelial cells after ischemic or toxic injury. Urinary NGAL and KIM-1 have never been evaluated in MM patients.To assess the value of these molecules in MM, we measured urinary and serum NGAL, urinary KIM-1, urinary and serum cystatin-C (cys-C; a sensitive marker of GFR which is not secreted in the urine) in 48 newly diagnosed symptomatic MM patients (27M/21F, median age 65 years). The estimated GFR (eGFR) was calculated using the CKD-EPI equation (proposed by the CKD Epidemiology Collaboration and is widely accepted in renal impairment). Serum and urinary NGAL was evaluated using an ELISA method (BioPorto Diagnostics A/S, Gentofte, Denmark) with a protocol applied in the Siemens Advia 1800 clinical chemistry system. Serum and urinary cys-C was measured on the BN ProSpec analyser using a latex particle-enhanced nephelometric immunoassay (Dade Behring-Siemens Healthcare Diagnostics, Liederbach, Germany), while urinary KIM-1 was also measured using an ELISA (R&D Systems, Minneapolis, MN, USA). For the urinary measurements, a 24h urine collection was used.Nine (19%) patients had sCr >2mg/dl, while 60% had eGFR ≥60 ml/min (CKD stages 1 & 2), 18.5% had eGFR 30–59 ml/min (CKD stage 3) and 21.5% eGFR <30 ml/min (CKD stages 4 & 5). The median values (range) for the studied markers in MM patients and in 120 healthy controls were: for urinary NGAL 36 ng/ml (0.5–2512 ng/ml) vs. 5.3 ng/ml (0.7–9.8 ng/ml), p<0.0001; for serum NGAL 162 ng/ml (53–576 ng/ml) vs. 63 ng/ml (37–106 ng/ml), p<0.0001; for urinary KIM-1 1.1 ng/ml (0.13–4.87 ng/ml) vs. 1.3 (0.1–5.3 ng/ml), p=0.345; for urinary Cys-C 0.05 mg/l (ND-13.9) vs. non-detectable, p<0.01; and for serum cys-C 1.0 mg/l (0.4–3.2 mg/l) vs. 0.7 (0.3–0.9 mg/l), p<0.01. Almost all patients (93%) had higher levels of urinary NGAL than the higher value of the controls; the respective frequency for the other markers was: 68% for serum NGAL and serum cys-C, 50% for urinary cys-C and only 10% for urinary KIM-1.All studied markers correlated with eGFR: serum cys-C (r=−0.758, p<0.001), serum NGAL (r=−0.627, p<0.001), urinary cys-C (r=−0.498, p=0.008), urinary NGAL (r=−0.430, p=0.01) and urinary KIM-1 (r=−0.369, p=0.021). Only serum cys-C strongly correlated with the involved serum free light chain (r=0.806, p<0.001). Urinary NGAL correlated also with urinary cys-C (r=0.880, p<0.001), serum NGAL (r=0.503, p=0.002), 24-h proteinuria (r=0.431, p=0.01) and ISS stage (mean±SD values for ISS-1, ISS-2 and ISS-3 were: 31±29 ng/mL, 47±52 ng/mL and 408±695 ng/mL, respectively; p=0.03). Serum cys-C correlated also with ISS stage (the values for ISS-1, ISS-2 and ISS-3 were: 0.85±0.19 mg/L, 0.94±0.24 mg/L and 2.15±0.98 mg/L, respectively; p=0.01), while urinary cys-C correlated with 24-h proteinuria (r=0.564, p<0.001).Our data suggest that almost all newly diagnosed symptomatic MM patients have tubular damage as assessed by elevated urinary NGAL suggesting that renal impairment is present very early in the disease course. Measurement of urinary NGAL and serum cys-C offers valuable information for the kidney function of MM patients and their measurement may help in the identification of patients with high risk for the development of acute renal function. The value of KIM-1 seems to be very low in myeloma reflecting the differences in the pathogenesis of myeloma-related renal dysfunction than toxic acute renal injury of other etiology. Disclosures:No relevant conflicts of interest to declare.

Serum and urinary neutrophil gelatinase-associated lipocalin as a predictor of rat kidney histopathology in an early ischemia-reperfusion model

Background: The severity of ischemia-reperfusion (I/R) kidney injury is highly correlated with mortality and morbidity rate. Research on human and animal prove that NGAL predicts kidney injury at early phase. The objective of this study is to prove that the increase in serum and urinary NGAL are correlated with kidney tubular epithelial damage, and this increase has occurred in initiation phase, indicated by rat kidney histopathology in an early I/R model. Methods: Twenty eight male Sprague-Dawley rats were divided into 4 groups: 4 hour sham (Sham 4), 8 hour sham (Sham 8), 10 minute ischemia 4 hour reperfusion (I/R 4) and 10 minute ischemia 8 hour reperfusion (I/R 8). Blood, urine and kidney samples were collected. Serum creatinine level was analyzed with Jaffe method, while serum and urinary NGAL level were analyzed with direct sandwich ELISA method. Evaluation of kidney damage were measured semi quantitatively in tissue stained with HE. Further evaluation to confirm cellular changes on kidney was performed by electron microscope and immunohistochemistry. Results: Serum NGAL was found significantly correlated with degree of kidney tissue damage (ρSpearman&nbsp;NGAL serum = 0.701, p &lt; 0.001), also urinary NGAL (ρSpearman = 0.689, p &lt; 0.001). NGAL expression differs significantly between I/R group and sham (t-test, t = -26635.056, p &lt; 0.001), also kidney damage (t-test, t = -5.028, p &lt; 0.001), and serum and urinary NGAL levels (Mann-Whitney, U = 0, p &lt; 0.001). With cutoff points of 136.95 ng/mL and 58.69 ng/mL subsequently for serum and urinary NGAL , it is found that sensitivity = 1, specificity = 1. Conclusion: Elevation of serum and urinary NGAL are significantly correlated with epithelial tubular kidney damage on rat undergoing early ischaemia reperfusion. (Med J Indones. 2012;21:208-13)

Urinary NGAL, but not L-FABP, in Early Post-Transplant Period, Predicts Graft Outcome Up to 1 Year after Kidney Transplantation

Background: Several recent reports demonstrated the usefulness of new biomarkers in early post-transplant period for predicting delayed graft function (DGF) after kidney transplantation. However, the usefulness of these biomarkers in predicting long-term graft outcome has scarcely been assessed. Methods: This was a prospective observational study, and only recipients without evidence of DGF, a well-known risk factor for poor long-term outcome, were included for the analysis (n=62). Urine samples at 0 hr, day 2 and 6 were obtained. Results: Urinary neutrophil gelatinase-associated lipocalin (u-NGAL) level on day 2, but not liver type fatty acid binding protein (L-FABP) or serum creatinine, was significantly higher in slow graft function (SGF) compared to immediate graft function (IGF) group. Higher day 2 u-NGAL level was associated with more frequent development of SGF and in addition, it was also associated with significantly lower 1yr estimated glomerular filtratrion rate (eGFR). In multivariate logistic regression analysis, day 2 u-NGAL was a significant, independent factor for predicting poor long-term graft function (1yr eGFR< 60ml/min/1.73m2). Conclusions: This study first demonstrated the possibility that u-NGAL might also be useful in predicting long-term graft outcome as well as short-term function even in patients who showed favorable early clinical course with early graft function (EGF).

Urinary NGAL and KIM-1: Biomarkers for Assessment of Acute Ischemic Kidney Injury Following Nephron Sparing Surgery

Nephron sparing surgery is considered the treatment of choice in most patients with confined renal cancer. Interrupting renal blood flow is often necessary during such surgery, which can induce significant renal injury. We explored the possibility of using urinary NGAL and KIM-1 excretion as novel biomarkers to assess the extent of acute kidney injury after nephron sparing surgery. The study group included 27 patients who underwent open nephron sparing surgery for enhancing solid renal tumors. During surgery the renal artery was clamped for between 6 and 47 minutes. Urine samples were collected before surgery, and 1, 3, 8, 24, 48 and 72 hours after renal pedicle clamp removal. Urinary levels of NGAL and KIM-1 were determined. Renal artery clamping induced renal injury, as reflected by increased urinary NGAL and KIM-1 in all participants. These increases in urinary NGAL excretion were evident after 1 hour of renal ischemia and lasted for 72 hours. Urinary NGAL correlated with the serum creatinine increase and ischemia duration. Compared with patients without significantly increased serum creatinine, those with significantly increased serum creatinine after nephron sparing surgery had a greater increase in urinary NGAL but not in KIM-1. Renal injury severity after nephron sparing surgery could be quantitatively assessed by measuring urinary NGAL and KIM-1.

Biomarkers for acute kidney injury: combining the new silver with the old gold

Over the last decade, the pursuit for drugs to prevent ortreat acute kidney injury (AKI) has been replaced by asearch for novel biomarkers of kidney damage. Promptedby expert opinion that lack of sensitive and specific bio-markers has thwarted progress in the field, several newbiomarkers have emerged and are jockeying to becomethe ‘golden’ test for AKI. As clinical experience withthese biomarkers accumulates, it is increasingly evidentthat no single biomarker will likely take the crown. Thereis a slow realization that the consistent emphasis on theweakness and limitations of existing markers may be mis-guided. In fact, there may be several opportunities to re-evaluate existing techniques in combination with newerbiomarkers for managing patients with AKI.Urine microscopy has long been considered to be awindow to the kidney; however, its clinical value wasquestioned after publications suggested that urinalysis wasnot helpful in discriminating between functional andintrinsic renal disorders, especially in sepsis [1–3]. Never-theless, there has been a recent resurgence in interest inurine microscopy as a tool to characterize AKI spurred bydata from two groups. Chawla et al. [4] developed an AKIcast scoring index to standardize urine sediment analysisand were able to show good precision of the index todetect acute tubular necrosis (ATN). In that study, urinesediment also correlated with outcomes in patients withATN. Renal recovery was worse in patients with a highercast scoring index (2.55±0.9 versus 1.7±0.79; P=0.04),and the area under the receiver operating characteristic(ROC) curve of the cast scoring index for the prediction ofnon-renal recovery was 0.79. Perazella et al. [5] proposeda different scoring system for differentiating ATN from de-creased kidney perfusion in AKI (pre-renal AKI). Usingfinal AKI diagnosis at discharge as the gold standard,urinary microscopy on the day of nephrology consultationwas highly predictive of ATN. The odds ratio for ATN in-crementally increased with a higher score. In patients withan initial diagnosis of ATN, any granular casts or renal epi-thelial tubular cells (corresponding to a score of 2) resultedin a positive predictive value of 100% and a negative pre-dictive value of 44%. Lack of renal epithelial tubular cellsor granular casts in patients with an initial diagnosis ofdecreased kidney perfusion (functional AKI) had a sensi-tivity of 0.73 and a specificity of 0.75 for the final diagno-sis of ATN. The same group developed a scoring pointsystem of urinary microscopy findings to predict adverseoutcomes [6]. They evaluated the correlation of urinarysediment score and the Acute Kidney Injury Network(AKIN) stage at nephrology consultation. The score ofurinary microscopy was associated with higher risk ofworsening AKI in a dose-dependent manner.In this issue of the journal, Schinstock et al. reinforcethe value of urinary microscopy as a predictor of AKI andAKI severity. They performed urine microscopy andmeasured Neutrophil Gelatinase-associated Lipocalin(NGAL) levels in urine samples collected in the emer-gency room (ER) from 363 patients who were sub-sequently admitted to the hospital. Patient charts werereviewed to determine whether they developed AKI usingthe AKIN creatinine criteria of a rise in creatinine of >0.3mg/dL within the 48 h following admission. Normalranges and thresholds for the NGAL ELISA were estab-lished in a cohort of 125 healthy volunteers. Seventy-sixpatients (21%) developed AKI with 65% in AKIN Stage1. Finding a renal epithelial cell, renal epithelial cellcast or granular cast had separately a high specificity(93.0–98.6%) to discriminate AKI from non-AKI patients.The presence of these elements as a group showed ahigher sensitivity (from 6 to 22%) and good specificity(91%), determining a low negative but high positive pre-dictive value (81.6). The discriminative performance waseven better when comparing more severe AKIN Stage 2or 3 from AKIN Stage 0 or 1: sensitivity 30%, specificity90% and positive predictive value 94%. In contrast, urineNGAL at ER admission had a sensitivity of 64.5% and aspecificity of 64.5% to predict the development of AKI,which was significantly lower than the admission serumcreatinine (sensitivity of 84.2% and specificity of 77.7%).Urine NGAL levels also predicted AKIN stage; however,urine microscopy additionally predicted death.Nickolas et al. [7], in a single-center study of ERpatients, showed sensitivities and specificities of urinary

Epoetin administrated after cardiac surgery: effects on renal function and inflammation in a randomized controlled study

BackgroundExperimentally, erythropoietin (EPO) has nephroprotective as well as immunomodulatory properties when administered after ischemic renal injury. We tested the hypothesis that different doses of recombinant human EPO administered to patients after cardiac surgery would minimize kidney lesions and the systemic inflammatory response, thereby decreasing acute kidney injury (AKI) incidence.MethodsIn this double-blinded randomized control study, 80 patients admitted to the ICU post-cardiac surgery were randomized by computer to receive intravenously isotonic saline (n = 40) versus α-Epoetin (n = 40): either 40000 IU (n = 20) or 20000 IU (n = 20). The study lasted one year. The primary outcome was the change in urinary NGAL concentration from baseline and 48 h after EPO injection. Creatinine, cystatine C and urinary NGAL levels were measured on the day of randomization and 2–4 days after EPO injection. To assess acute inflammatory response, serum cytokines (IL6 and IL8) were measured at randomization and four days after r-HuEPO injection. Patients and care-takers were blinded for the assignment.ResultsNo patient was excluded after randomization. Patient groups did not differ in terms of age, gender, comorbidities and renal function at randomization. The rate of AKI assessed by AKIN criteria was 22.5% in our population. EPO treatment did not significantly modify the difference in uNGAl between 48 hours and randomization compared to placebo [2.5 ng/ml (−17.3; 22.5) vs 0.7 ng/ml (−31.77; 25.15), p = 0.77] and the incidence of AKI was similar. Inflammatory cytokines levels were not influenced by EPO treatment. Mortality and hospital stays were similar between the groups and no adverse event was recorded.ConclusionIn this randomized-controlled trial, α-Epoetin administrated after cardiac surgery, although safe, demonstrated neither nephroprotective nor anti-inflammatory properties.Trial registration numberNCT00676234