Acute hyperbilirubinemia determines an early subclinical renal damage: Evaluation of tubular biomarkers in cholemic nephropathy.

BACKGROUND AND AIMS: Cholemic nephropathy is a cause of acute kidney injury occurring in patients with jaundice. The aim of this study was to evaluate early renal function impairment in patients with mild acute hyperbilirubinemia in the absence of alterations of the common parameters used in clinical practice (serum creatinine or urea) and with normal renal morphology. We studied urinary biomarkers of tubular damage urinary neutrophil gelatinase-associated lipocalin (u-NGAL), urinary beta-2-microglobulin (u-B2M), urinary osteopontin (u-OPN), urinary trefoil factor 3 (u-TFF3) and urinary Cystatin C (u-Cys). METHODS: This is a case-control study investigating the following urinary biomarkers of tubular damage: u-NGAL, u-B2M, u-OPN, u-TFF3 and u-Cys, in patients with mild acute hyperbilirubinemia. Seventy-four patients were included in this study: 36 patients with jaundice and 38 patients without jaundice. RESULTS: Subjects with jaundice (total bilirubin 12.4 ± 7.3 mg/dL) showed higher u-NGAL, u-B2M, u-OPN, u-TFF3 and u-Cys compared with controls. After logistic regression analyses, including the following independent variables: age, estimated Glomerular Filtration Rate (eGFR), haemoglobin, diabetes, hypertension and jaundice, we observed a higher risk of elevated u-NGAL values (OR = 3.8, 95% CI 1.07-13.5, p = .03) and u-B2M (OR = 9.4, 95% CI 2.3-38.9, p = .0018) in jaundiced subjects. Moreover, urinary biomarkers had a direct correlation with serum cholestasis indexes. CONCLUSIONS: This study demonstrated increased urinary biomarkers of tubular damage (u-NGAL, u-B2M, u-OPN, u-TFF3, and u-Cys) in patients with mild hyperbilirubinemia in comparison with a control group. These findings suggest early renal tubular damage in the absence of alterations of the normal parameters used in clinical practice (eGFR, serum urea and renal morphology).

Perioperative Acute Renal Injury: Revisiting Pathophysiology.

BACKGROUND: Acute renal dysfunction and subsequent acute renal failure after cardiac surgery are associated with high mortality and morbidity. Early therapeutic or preventive intervention is hampered by the lack of an early biomarker for acute renal injury. Recent studies showed that urinary neutrophil gelatinase-associated lipocalin (NGAL or lipocalin 2) is upregulated early (within 1 to 3 h) after murine renal injury and in pediatric acute renal dysfunction after cardiac surgery. The authors hypothesized that postoperative urinary NGAL concentrations are increased in adult patients developing acute renal dysfunction after cardiac surgery compared with patients without acute renal dysfunction. METHODS: After institutional review board approval, 81 cardiac surgical patients were prospectively studied. Urine samples were collected immediately before incision and at various time intervals after surgery for NGAL analysis by quantitative immunoblotting. Acute renal dysfunction was defined as peak postoperative serum creatinine increase by 50% or greater compared with preoperative serum creatinine. RESULTS: Sixteen of 81 patients (20%) developed postoperative acute renal dysfunction, and the mean urinary NGAL concentrations in patients who developed acute renal dysfunction were significantly higher early after surgery (after 1 h, mean ± SD, 4,195 ± 6,520 vs. 1,068 ± 2,129 ng/ml; P < 0.01) compared with patients who did not develop acute renal dysfunction. Mean urinary NGAL concentrations continued to increase and remained significantly higher at 3 and 18 h after cardiac surgery in patients with acute renal dysfunction. In contrast, urinary NGAL in patients without acute renal dysfunction decreased rapidly after cardiac surgery. CONCLUSIONS: Patients developing postoperative acute renal dysfunction had significantly higher urinary NGAL concentrations early after cardiac surgery. Urinary NGAL may therefore be a useful early biomarker of acute renal dysfunction after cardiac surgery. These findings may facilitate the early detection of acute renal injury and potentially prevent progression to acute renal failure.

Endotoxic kidney injury in Beagle dogs assessed by serum creatinine and symmetric dimethylarginine, and urinary neutrophil gelatinase-associated lipocalin and clusterin.

Sepsis of Gram negative bacterial origin results in lipopolysaccharide-induced endotoxemia. This often leads to acute kidney injury (AKI) and its recognition remains a challenge and delays treatment. As renal damage occurs before a rise in serum creatinine is detected, new early biomarkers of kidney injury need to be explored. The aim of this study was to determine changes in serum parameters of renal function and urine biomarkers of renal injury. This was a descriptive study. Endotoxemia was induced intravenously in six anaesthetized Beagles (T1). To achieve normotension, dogs received fluids (T2), followed by a continuous infusion of noradrenaline and dexmedetomidine or 0.9% NaCl (T3). Ten minutes later, the dogs received fluids (T4) and noradrenaline and dexmedetomidine or 0.9% NaCl in a crossover manner (T5). At each timepoint, blood and urine were collected for serum creatinine, urea, symmetric dimethylarginine, urine protein/creatinine (UPC) ratio, urine neutrophil-gelatinase-associated lipocalin (U-NGAL), U-NGAL/creatinine ratio, urine clusterin (U-clusterin) and U-clusterin/creatinine ratio. Data were analyzed using a mixed-effect model taking into account time and stage of veterinary AKI (VAKI). Three of six dogs had a VAKI stage ≥1; one with anuria and elevated creatinine. Serum creatinine (P < 0.001), U-NGAL/creatinine ratio (P = 0.01) and U-clusterin/creatinine ratio increased over time (P < 0.01). The UPC ratio (mean (range) 0.68 (0.35-2.3) versus 0.39 (0.15-0.71) P < 0.01) and U-NGAL (3164 pg/mL (100-147,555) versus 100 (100-14,524), P = 0.01) were higher in VAKI stage ≥1 versus stage 0, respectively. Endotoxemia induced VAKI stage ≥1 in half of the dogs. Repeated measurement of selected parameters could detect AKI early.

Relationship between neutrophil gelatinase-associated lipocalin levels and disease parameters including clinicopathological parameters and various cytokine levels in systemic lupus erythematosus.

Urine neutrophil gelatinase-associated lipocalin (NGAL) is a marker of acute kidney injury and indicates tubular damage. Lupus nephritis-associated renal injury is characterized by damage to the glomeruli and tubular portions of the kidneys. Therefore, NGAL concentrations are expected to vary according to the severity of systemic lupus erythematosus (SLE). In this study, samples from (NZB × NZW) F1 mice at an advanced stage of SLE were used to determine whether serum and urine NGAL concentrations or the urine NGAL:creatinine (uNGAL/C) ratio can be used to reflect diet, disease state, and treatment efficacy. Additionally, the relationship between the levels of NGAL and various cytokines in the serum in SLE was evaluated. Mice were divided into the following four groups (n=15): CN, chow diet and no treatment (saline; intraperitonially injected [i.p.]; 200 µL/day); CP, chow diet and methylprednisolone (i.p.; 5 mg/kg/day); HN, high-fat diet and no treatment (saline [i.p.]; 200 µL/day); and HP, high-fat diet and methylprednisolone treatment (i.p.; 5 mg/kg/day) every day from 6 to 42 weeks of age. The serum and urine NGAL levels and uNGAL/C values were significantly lower in the CP group than those in the CN group. Further, serum NGAL concentration demonstrated a strong positive correlation with urine NGAL levels, uNGAL/C, urine protein concentrations, urine protein:creatinine ratio, and the expression of several cytokines associated with SLE pathogenesis (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and interferon-induced protein [IP]-10). These results suggest that NGAL has a strong positive correlation with the clinicopathological parameters and several key cytokines in SLE.

Novel Finding of Urinary Erythropoietin as an Early Biomarker of Cisplatin-Induced Nephrotoxicity.

Cisplatin is a chemotherapeutic drug used to treat a great variety of solid tumors. Its dose is commonly limited by its nephrotoxicity, manifested as acute kidney injury (AKI). Erythropoietin (Epo) is a glycoprotein hormone that regulates the production of red blood cells. This study was performed to evaluate the presence of endogenous Epo in male Wistar rat urine and to analyse changes in urinary Epo levels in response to cisplatin- induced AKI. Dose-dependent studies and time-dependent experiments were performed to evaluate changes in urea nitrogen and creatinine in plasma as well as Epo, neutrophil gelatinase-associated lipocalin (NGAL), alkaline phosphatase (AP) activity, creatinine and total proteins in urine at 2 days post-dosing. Rats received 2, 5 or 10 mg/kg b.w., i.p. of cisplatin. At 5 mg/kg b.w., i.p. cisplatin, significant increases in urinary Epo were detected. Significant increases in urea nitrogen and creatinine in plasma, NGAL, AP, proteins, and Epo were observed in urine from rats that received 10 mg/kg b.w., i.p. of cisplatin. In the time-dependent experiments, rats were injected with a dose of 5 mg/kg b.w., i.p. of cisplatin, and sampling occurred 2, 4, and 14 days post-dosing. In these animals, there were significant increases in urea nitrogen and creatinine in plasma and total proteins, AP activity, Epo, and NGAL in urine on day 4. Urinary Epo was also detected on day 2. Taken together, these findings provide weight of evidence for urinary Epo as a promising early biomarker of cisplatin-induced AKI in male rats.

Preoperative and postoperative urinary NGAL levels in children with bladder exstrophy.

BACKGROUND: Urinary NGAL (neutrophil gelatinase-associated lipocalin) levels have been shown to predict renal damage in various medical conditions. The present study was conducted to study the role of urinary NGAL levels in children with bladder exstrophy-epispadias complex post single-stage total reconstruction (SSTR) as markers of early renal function reduction. METHODS: Urine samples were collected from children with bladder exstrophy before SSTR (Group A, n = 11), 5 years post SSTR (Group B, n = 40) and controls (Group C, n = 41) and stored at - 20 °C. NGAL levels were estimated using double antibody sandwich ELISA. RESULTS: Mean NGAL levels in Groups A, B and C were 1.39, 34.24 and 2.58 ng/ml, respectively. Mean NGAL levels among Group B subjects with glomerular filtration rate (GFR) ≥ 80 ml/min/1.73 m2 body surface area (BSA) was 29.8 ng/ml, while it was 31.74 ng/ml in those with GFR < 80 ml/min. Urine samples were also evaluated 6 months post SSTR. Mean NGAL at 6 months was 6.76 ng/ml, while at 12 months it was 30.3 ng/ml, remaining > 30 ng/ml at 18 and 24 months. Dimercaptosuccinic acid (DMSA) scans did not show any scarring, and GFR on diethylenetriamine pentaacetate (DTPA) scans remained stable. CONCLUSIONS: Increasing levels of urinary NGAL following bladder-exstrophy and epispadias complex repair suggest that NGAL detects the earliest signs of renal damage even before any deterioration is observed in DMSA and/or DTPA-GFR scans. Further studies with an adequate sample size and periodic measurement of NGAL need to be performed before any definitive conclusion can be drawn.

Urinary neutrophil gelatinase-associated lipocalin predicted to contrast-associated acute kidney injury after planned percutaneous coronary intervention in elderly patients.

AIM: To determine the proportion of contrast-associated acute kidney injury (CA-AKI) after percutaneous coronary intervention (PCI) and the predictive value of urine neutrophil gelatinase-associated lipocalin (uNGAL) for CA-AKI in elderly patients with chronic coronary artery disease. METHODS: A total of 509 patients who had planned percutaneous coronary intervention (mean age was 63.58 ± 11.63 years and 63.3% of males) were divided into two groups: group 1 (n = 153; elderly patients) with ≥70 years old and group 2 (n = 356) with <70 years old. Urine NGAL was measured by the ELISA method. Clinical and laboratory data were collected on the day before intervention. CA-AKI was defined based on Kidney Disease: Improving Global Outcomes criteria. RESULTS: The ratio of CA-AKI in group 1 was 23.5% which was higher than that of group 2 (8.7%) with a p-value < 0.001. Urine NGAL level in group 1 was significantly higher than that of group 2 [31.3 (19.16-55.13) ng/ml vs. 19.86 (13.21-29.04) ng/ml, p < 0.001]. At a cut-off value of 44.43 ng/ml, uNGAL had a predictive value for CA-AKI in all patients (AUC = 0.977, p < 0.001). Especially at a cut-off value of 44.14 ng/ml, uNGAL had a predictive value for CA-AKI in elderly patients (AUC = 0.979, p < 0.001). CONCLUSIONS: The rate of CA-AKI after PCI in elderly patients was 23.5%. Urine NGAL before PCI had a good predictive value for CA-AKI in elderly patients with chronic coronary artery disease.

Urinary Neutrophil Gelatinase-Associated Lipocalin Predicts Intensive Care Unit Admission Diagnosis: A Prospective Cohort Study.

Background: Acute kidney injury (AKI) is most commonly caused by tubular injury and is associated with a wide variety of critical illnesses. It is well known that urinary biomarkers can lead to the early identification of AKI. However, the ability of urinary biomarkers to distinguish between different types of critical illness has been less studied. Methods: In this prospective cohort study, urinary neutrophil gelatinase-associated lipocalin (uNGAL) was measured in 107 patients consecutively admitted to the ICUs in our tertiary medical center. uNGAL samples were collected within 3-6 hours of admission to an ICU and measured by ELISA. All data were analyzed using R statistical software, and univariate analysis was used to determine the correlations of uNGAL levels with AKI stage, admission diagnoses, and ICU course. Results: uNGAL level increased by a mean of 24-fold (SD 10-59) in ICU patients with AKI and demonstrated a significant correlation with the different AKI stages. uNGAL predicted the need for RRT, with values increased by more than 15-fold (P<0.05) in patients needing RRT, and remained a useful tool to predict AKI in ICU patients with a urinary tract infection. uNGAL level was correlated with certain ICU admitting diagnoses whereby uNGAL levels were lower in ICU patients with cardiogenic shock compared with other admission diagnoses (ß=-1.92, P<0.05). Conclusions: uNGAL can be used as an early predictor of AKI and its severity in patients admitted to the ICU, including the need for RRT. uNGAL may also help in distinguishing patients with cardiogenic shock from those with other critical illnesses and identifying those at risk for poor outcomes irrespective of the presence of AKI.

The effect of interval and continuous work on markers of acute kidney injury in a hot environment.

PURPOSE: To examine the effect of high-intensity interval work (HIIW) and moderate-intensity continuous work (MICW) on markers of acute kidney injury (AKI) and kidney function in a hot environment. METHODS: Nine males completed 2 h of work (2 × 60 min with 10 min passive rest) in a hot environment (40 °C and 15% relative humidity) as either HIIW [2 min at 80% peak oxygen consumption (VO2peak) and 3 min at 30% VO2peak] or MICW (matched for total work of HIIW). Blood and urine samples were collected immediately before (Pre), after (Post), 1 h (1 h Post), and 24 h after (24 h Post) the trials. Urine flow rate (UFR), creatinine clearance, insulin-like growth factor binding protein 7 (IGFBP7), urinary neutrophil gelatinase-associated lipocalin (uNGAL), and urinary kidney injury marker 1 (uKIM-1) were measured to assess kidney function and injury. RESULTS: Log IGFBP7 (p < 0.01), log uNGAL (p < 0.01), and log uKIM-1 (p = 0.01) all displayed a main effect for time after both HIIW and MICW. IGFBP7 (p = 0.01) and uKIM-1 (p < 0.01), corrected for Uosm, were higher after HIIW compared to MICW at Post, while IGFBP7 was also higher 1 h Post after HIIW compared to MICW (p = 0.02). UFR significantly decreasing from Pre to Post (p < 0.01) and 1 h Post (p < 0.01), but no main effect for condition (p = 0.53). CONCLUSION: Both HIIW and MICW in a hot environment caused an increase in biomarkers of kidney injury (IGFBP7, KIM-1, and NGAL), but HIIW may have a greater impact on biomarkers related to AKI.

Comparative Evaluation of Two NGAL Automated Immunoassays in Urine and Plasma.

BACKGROUND: Acute kidney injury (AKI), a frequent and serious complication of hospitalized patients, is associated with increased mortality and morbidity. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for the early identification of AKI. We report a comparative laboratory verification of the Abbott Diagnostics (ARCHITECT® urine NGAL) and BioPorto Diagnostics (NGAL TestTM) assays including an assessment of the Abbott assay's performance in EDTA plasma. METHODS: Intra-/interbatch imprecision, linearity, recovery, and limit of quantitation (LoQ) were assessed and an interassay comparison performed (n = 51). Between-laboratory agreement was assessed against other laboratories using the Abbott (n = 48) and BioPorto (n = 94) assays. Plasma NGAL (pNGAL) levels were measured in non-AKI patients with a range of estimated glomerular filtration rates (n = 80). RESULTS: Coefficients of variation (CVs) for intra- and interbatch imprecision were 0.7%-12.4% and 1.9%-27.5% for the BioPorto assay, respectively, and 1.4%-6.3%/3.4%-6.8%, respectively, for the Abbott assay. The BioPorto assay exhibited a higher LoQ (27.5 ng/mL vs 1.2 ng/mL). Both assays were linear over the range 5-6000 ng/mL. Recovery of recombinant NGAL was 113.1 ± 7.1% and 96.5 ± 7.8% for the Abbott and BioPorto assays, respectively. On average, the Abbott assay gave results 9.2% lower than the BioPorto assay. Mean differences of 0.2% (Abbott) and 20.2% (BioPorto) were observed in the between-laboratory comparison. In patients without AKI, pNGAL levels were inversely proportional to eGFR. CONCLUSIONS: Performance of the Abbott and BioPorto assays was similar although the latter performed less well at lower NGAL concentrations. The Abbott assay tended to yield lower results, exhibited a lower LoQ and over-recovered NGAL. Although only Conformité Européenne-marked and marketed for use in urine, the Abbott assay demonstrated equivalent performance to the BioPorto assay with EDTA plasma.

Detection of subclinical nephrotoxicity induced by aminoglycosides in critically ill elderly patients using trough levels and urinary neutrophil gelatinase-associated lipocalin.

OBJECTIVES: Early detection of aminoglycoside-induced acute kidney injury (AKI) is crucial in intensive care unit (ICU) patients, but it is not adequately reflected by serum creatinine (SrCr) levels. This study proposed investigating the relationship between amikacin trough levels and the development of nephrotoxicity using both conventional markers and a new biomarker of renal function in critically ill elderly patients. METHODS: Thirty-three critically ill patients aged ≥65 years with normal SrCr who received once-daily amikacin were evaluated. Trough levels of amikacin, creatinine clearance (CrCL) and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were measured during the 10-day study period. The patients were divided into three groups and were compared based on the trough levels on both day 3 and day 7: <3 µg/mL (low trough (LT)), 3-6 µg/mL (moderate trough (MT)) and >6 µg/mL (high trough (HT)). RESULTS: In the LT group, neither CrCL nor uNGAL levels significantly changed from baseline (p=0.364 and p=0.562, respectively). In the MT group, the CrCL level altered significantly over time from baseline (p=0.007), but the uNGAL level did not change significantly over the study period (p=0.916). In the HT group, both CrCL and uNGAL levels significantly changed from baseline during the study period (p=0.002 and p=0.046, respectively). CONCLUSIONS: In critically ill elderly patients with MT, the mean uNGAL level changed at least 4 days earlier than the SrCr level. Instead, the trough level of amikacin demonstrated a potential value for predicting subclinical AKI for implementing necessary interventions. Amikacin trough levels <3 µg/mL in the once-daily dosing regimen appeared safe, even in geriatric patients. Further studies are needed to confirm this finding.

Association between Neutrophil Gelatinase-Associated Lipocalin and Fetal Hemoglobin Levels in Patients with Type 2 Diabetes Mellitus.

The effect of neutrophil gelatinase-associated lipocalin (NGAL) on fetal hemoglobin (HbF) levels in diabetic patients is rarely investigated. This study is aimed at investigating the possible association between NGAL and HbF levels in type 2 diabetes mellitus (T2DM). A total of 160 patients with T2DM and 61 healthy individuals were evaluated. NGAL, HbF, tumor necrosis factor-α (TNF-α), interleukin-5 (IL-5), glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and urine albumin levels were measured. HbF levels were significantly higher in patients with elevated NGAL than in those without elevated NGAL (1.44% versus 0.94%, P = 0.001). High HbF was 2.3 times more prevalent in patients with elevated NGAL than in those without elevated NGAL. In addition, NGAL, TNF-α, and IL-5 levels were significantly higher in patients with high HbF than in those with low HbF; however, there was no significant difference in HbA1c and FPG levels between the two groups. HbF was positively correlated with NGAL (r = 0.275, P < 0.001), TNF-α (r = 0.256, P < 0.001), and IL-5 (r = 0.212, P < 0.001), but not with HbA1c and FPG. An elevated NGAL level led to a 1.27-fold increase in the prevalence of high HbF (odds ratio: 1.27, 95% CI: 1.03-2.51, and P < 0.001). The diagnostic efficacy of NGAL to identify an elevated HbF level was superior to that of HbA1c (area under the curve: 0.697, 95% CI: 0.609-0.786 versus 0.584, 95% CI: 0.488-0.681, and P = 0.022). In conclusion, enhanced NGAL production may be closely linked to elevated HbF in conjunction with proinflammatory cytokines in patients with T2DM.

A panel of urinary proteins predicts active lupus nephritis and response to rituximab treatment.

OBJECTIVES: ∼30% of patients with SLE develop LN. Presence and/or severity of LN are currently assessed by renal biopsy, but biomarkers in serum or urine samples may provide an avenue for non-invasive routine testing. We aimed to validate a urinary protein panel for its ability to predict active renal involvement in SLE. METHODS: A total of 197 SLE patients and 48 healthy controls were recruited, and urine samples collected. Seventy-five of the SLE patients had active LN and 104 had no or inactive renal disease. Concentrations of lipocalin-like prostaglandin D synthase (LPGDS), transferrin, alpha-1-acid glycoprotein (AGP-1), ceruloplasmin, monocyte chemoattractant protein 1 (MCP-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were quantified by MILLIPLEX® Assays using the MAGPIX Luminex platform. Binary logistic regression was conducted to examine whether proteins levels associate with active renal involvement and/or response to rituximab treatment. RESULTS: Urine levels of transferrin (P <0.005), AGP-1 (P <0.0001), MCP-1 (P <0.001) and sVCAM-1 (P <0.005) were significantly higher in SLE patients when compared with healthy controls. Furthermore, levels of transferrin, AGP-1, ceruloplasmin, MCP-1 and sVCAM-1 (all P <0.0001) were higher in SLE patients with active LN when compared with patients without active LN. A combination of five urine proteins, namely LPGDS, transferrin, ceruloplasmin, MCP-1 and sVCAM-1 was a good predictor of active LN (AUC 0.898). A combined model of LPGDS, transferrin, AGP-1, ceruloplasmin, MCP-1 and sVCAM-1 predicted response to rituximab treatment at 12 months (AUC 0.818). CONCLUSIONS: Findings support the use of a urinary protein panel to identify active LN and potentially predict response to treatment with rituximab in adult SLE patients. Prospective studies are required to confirm findings.

Vulpeculin: a novel and abundant lipocalin in the urine of the common brushtail possum, Trichosurus vulpecula.

Lipocalins are a family of secreted proteins. They are capable of binding small lipophilic compounds and have been extensively studied for their role in chemosignalling in rodent urine. Urine of the common brushtail possum (Trichosurus vulpecula) contains a prominent glycoprotein of 20 kDa, expressed in both sexes. We have isolated this protein and determined its primary sequence by mass spectrometry, including the use of metabolic labelling to resolve the leucine/isoleucine isobaric ambiguity. The protein sequence was identified as a lipocalin, and phylogenetic analysis grouped the protein with other marsupial lipocalin sequences in a phylogenetic clade distinct from established cross-species lipocalin sub-families. The pattern of expression in possum urine and the similarity in sequence and structure to other lipocalins suggests this protein may have a role in brushtail possum chemosignalling.

Urinary Neutrophil Gelatinase Associated Lipocalins (NGALs) predict acute kidney injury post liver transplant.

BACKGROUND: Acute Kidney Injury, a common complication of liver transplant, is associated with a significant increase in the risk of morbidity, mortality and graft loss. Current diagnostic criteria leaves a delay in diagnosis allowing further potential irreversible damage. Early biomarkers of renal injury are of clinical importance and Neutrophil Gelatinase Associated Lipocalins (NGALs) and Syndecan-1 were investigated. METHODS: AKI was defined according to the Acute Kidney Injury Network criteria. Urine and blood samples were collected pre-operatively, immediately post-op and 24 h post reperfusion to allow measurement of NGAL and Syndecan-1 levels. RESULTS: 13 of 27 patients developed an AKI. Patients who developed AKI had significantly higher peak transaminases. Urinary NGAL, plasma NGAL and Syndecan-1 levels were significantly elevated in all patients post reperfusion. Urinary NGAL levels immediately post-op were significantly higher in patients who developed an AKI than those that didn't [1319 ng/ml vs 46.56 ng/ml, p ≤ 0.001]. ROC curves were performed and urinary NGAL levels immediately post-op were an excellent biomarker for AKI with an area under the curve of 0.948 (0.847-1.00). CONCLUSIONS: Urinary NGAL levels measured immediately post-op accurately predict the development of AKI and their incorporation into clinical practise could allow early protocols to be developed to treat post transplant AKI.

Urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, uromodulin, and cystatin C concentrations in an experimental rat model of ascending acute kidney injury induced by pyelonephritis.

Recent evidence suggests that neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C (CysC), uromodulin (UMOD), and some interleukins (IL-6 and IL-18) can be considered as diagnostic markers of acute kidney injury (AKI). The aim of this study was to verify the applicability of four urinary (u) markers, namely uNGAL, uKIM-1, uCysC, and uUMOD, for the diagnosis of ascending AKI induced by bacterial pyelonephritis. The study included 30 female rats that were divided into three groups (n = 10 each) and were inoculated transurethrally with various doses of Escherichia coli to induce isolated pyelonephritis (group 1, 105 CFU/ml), pyelonephritis-induced AKI (group 2, 107 CFU/ml), or AKI and urosepsis (group 3, 109 CFU/ml). The inoculate contained a highly virulent E. coli strain isolated from a patient with pyelonephritis. Urine samples were obtained prior to the inoculation and 7, 14, and 21 days thereafter. The concentrations of all assessed proteins were determined in the urine samples by ELISA. All the study groups showed elevated concentrations of uNGAL and uCysC at all study time points. The concentrations of uKIM-1 in group 1 were the same as that at the baseline, whereas it was elevated in groups 2 and 3 at all study time points. The concentrations of uUMOD in groups 1 and 2 tended to decrease with the time from inoculation, whereas it rapidly increased in group 3 at 21 days postinfection. uKIM-1 seems to be the only marker of ascending AKI associated with urinary tract infection. Elevated concentrations of uNGAL, uCysC, and uUMOD were found in both AKI and isolated pyelonephritis. Thus, it can be concluded that none of these markers can be used as a single diagnostic marker of ascending AKI, as it may produce false-negative results, leading to incorrect diagnosis, lack of adequate treatment, and increased mortality risk.

Alteration of urinary neutrophil gelatinase-associated lipocalin as a predictor of tacrolimus-induced chronic renal allograft fibrosis in tacrolimus dose adjustments following kidney transplantation.

Despite tacrolimus (TAC) drug-level monitoring, TAC-induced chronic renal allograft fibrosis remains an important problem. This study investigated the potential of urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a chronic renal allograft fibrosis biomarker in a two-phase study (proof of concept and cohort). In the proof of concept stage of the study, increased TAC-doses at 3 days after dose adjustment compared with the baseline were associated with elevated uNGAL (+ΔuNGAL) and urinary interleukin 18 (IL-18), but normal serum creatinine (SCr), despite the therapeutic trough levels of TAC. In the cohort study, the patients with elevated uNGAL post-recruitment in comparison with the baseline (+ΔuNGAL) was associated with the more severe renal allograft fibrosis from renal pathology of the protocol biopsy at 12 months post kidney transplantation (post-KT). A cut-off value of uNGAL ≥ 125.2 ng/mL during a 3, 6, 9 and 12 months post-KT was associated with a higher fibrosis score, with an area under the receiver operating characteristics curve of 0.80 (95% confidence interval [CI] 0.72 to 0.88, p < 0.0001) and a hazard ratio (HR) of 2.54 (95% CI 1.45 to 9.33; p < 0.001). We conclude that uNGAL is a sensitive biomarker of TAC induced subtle renal injury and TAC-induced chronic renal allograft fibrosis. We propose that uNGAL measurements, in addition to trough levels of TAC, should be used to predict TAC-induced chronic renal allograft fibrosis in the recipients of KT.

Growing international evidence for urinary biomarker panels identifying lupus nephritis in children - verification within the South African Paediatric Lupus Cohort.

BACKGROUND: A urinary biomarker panel including alpha-1-acid-glycoprotein (AGP), lipocalin-like-prostaglandin-D-synthase (LPGDS), transferrin and ceruloplasmin demonstrates an 'excellent' ability for identifying active lupus nephritis in UK/US children. This study aimed to assess whether this panel identifies active lupus nephritis within the South African Paediatric Lupus Cohort. METHODS: Juvenile-onset-systemic lupus erythematosus (JSLE) patients aged < 19 years at diagnosis and healthy controls were recruited. Patients were categorized as having active lupus nephritis (renal BILAG score; A/B and previous histological confirmation) or inactive lupus nephritis (renal BILAG score: D/E). Urinary biomarkers were quantified by ELISA. Mann-Whitney U-test compared biomarker levels between groups. Binary logistic regression and receiver operating curve analysis assessed biomarker combinations. RESULTS: Twenty-three juvenile-onset-systemic lupus erythematosus patients were recruited with a median age of 13.5 years (interquartile range (IQR) 12.7-14.9) and disease duration of 2.6 years (IQR 1.8-4.0). Eighteen healthy controls had a median age of 11.0 years (IQR 10.0-12.0). AGP, LPGDS, transferrin, ceruloplasmin and VCAM-1 were significantly higher in active than in inactive lupus nephritis patients (corrected p-values, all pc < 0.05), with no difference between inactive lupus nephritis patients and healthy controls (all pc = 1.0). The optimal biomarker combination included AGP, ceruloplasmin, LPGDS and transferrin (area under the curve = 1.0). CONCLUSIONS: A urinary biomarker panel comprising AGP, ceruloplasmin, LPGDS and transferrin previously validated within UK/US cohorts also performed excellently within a racially distinct South African cohort which displayed more severe lupus nephritis.

Effect of Repeated Injection of Iodixanol on Renal Function in Healthy Wistar Rats Using Functional MRI.

PURPOSE: To determine the optimal time interval of repeated intravenous injections of iodixanol in rat model and to identify the injury location and causes of renal damage in vivo. MATERIALS AND METHODS: Rats were randomly divided into Control group, Group 1 with one iodixanol injection, and Group 2 with two iodixanol injections. Group 2 was subdivided into 3 cohorts according to the interval between the first and second iodixanol injections as 1, 3, and 5 days, respectively. Blood oxygen level-dependent (BOLD) imaging and diffusion weighted imaging (DWI) were performed at 1 hour, 1 day, 3 days, 5 days, and 10 days after the application of solutions. RESULTS: Compared with Group 1 (7.2%), Group 2 produced a remarkable R2⁎ increment at the inner stripe of the renal outer medulla by 15.37% (P = 0.012), 14.83% (P = 0.046), and 13.53% (P > 0.05), respectively, at 1 hour after repeated injection of iodixanol. The severity of BOLD MRI to detect renal hypoxia was consistent with the expression of HIF-1α and R2⁎ was well correlated with HIF-1α expression (r = 0.704). The acute tubular injury was associated with urinary NGAL and increased significantly at 1 day. CONCLUSIONS: Repetitive injection of iodixanol within a short time window can induce acute kidney injury, the impact of which on renal damage in rats disappears gradually 3-5 days after the injections.