Prolonged Changes in Hepatic Mitochondrial Activity and Insulin Sensitivity by High Fructose Intake in Adolescent Rats

Persistence of damage induced by unhealthy diets during youth has been little addressed. Therefore, we investigated the impact of a short-term fructose-rich diet on liver metabolic activity in adolescent rats and the putative persistence of alterations after removing fructose from the diet. Adolescent rats were fed a fructose-rich diet for three weeks and then switched to a control diet for further three weeks. Body composition and energy balance were not affected by fructose-rich diet, while increased body lipids and lipid gain were found after the rescue period. Switching to a control diet reversed the upregulation of plasma fructose, uric acid, lipocalin, and haptoglobin, while plasma triglycerides, alanine aminotransferase, lipopolysaccharide, and tumor necrosis factor alpha remained higher. Hepatic steatosis and ceramide were increased by fructose-rich diet, but reversed by returning to a control diet, while altered hepatic response to insulin persisted. Liver fatty acid synthase and stearoyl-CoA desaturase (SCD) activities were upregulated by fructose-rich diet, and SCD activity remained higher after returning to the control diet. Fructose-induced upregulation of complex II-driven mitochondrial respiration, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, and peroxisome proliferator activated receptor α also persisted after switching to control diet. In conclusion, our results show prolonged fructose-induced dysregulation of liver metabolic activity.

Predictive value of cystatin C and neutrophil gelatinase-associated lipocalin in contrast-induced nephropathy: A meta-analysis

Background

There are still limited studies comprehensively examining the diagnostic performance of neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C in contrast-induced nephropathy (CIN). The study aimed to investigate and compare the predictive value of NGAL and cystatin C in the early diagnosis of CIN.

Methods and materials

We searched the PubMed, EMBASE and Cochrane Library databases until November 10, 2019. The methodological quality of the included studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) modeling were performed to summarize and compare the diagnostic performance of blood/urine NGAL and serum cystatin C in CIN. Subgroup and meta-regression analyses were performed according to the study and patient characteristics.

Results

Thirty-seven studies from thirty-one original studies were included (blood NGAL, 1840 patients in 9 studies; urine NGAL, 1701 patients in 10 studies; serum cystatin C, 5509 patients in 18 studies). Overall, serum cystatin C performed better than serum/urine NGAL (pooled DOR: 43 (95%CI: 12–152); AUROC: 0.93; λ: 3.79); serum and urine NGAL had a similar diagnostic performance (pooled DOR: 25 (95%CI: 6–108)/22(95%CI: 8–64); AUROC: 0.90/0.89; λ: 3.20/3.08). Meta-regression analysis indicated that the sources of heterogeneity might be CIN definition, assays, and nationalities.

Conclusion

Both NGAL and cystatin C can serve as early diagnostic indicators of CIN, while cystatin C may perform better than NGAL.

High sPLA2-IIA level is associated with eicosanoid metabolism in patients with bacterial sepsis syndrome

The aim of this study was to determine the association between secretory phospholipase A2 group IIA (sPLA2-IIA) and eicosanoid pathway metabolites in patients with bacterial sepsis syndrome (BSS). Levels of sPLA2-IIA, eicosanoids prostaglandin (PG)E2, PGD synthase were quantified in the sera from patients confirmed to have bacterial sepsis (BS; N = 45), bacterial severe sepsis/septic shock (BSS/SS; N = 35) and healthy subjects (N = 45). Cyclooxygenase (COX)-1 and COX-2 activities were analyzed from cell lysate. Serum levels of sPLA2-IIA, PGE2, and PGDS increased significantly in patients with BS and BSS/SS compared to healthy subjects (p<0.05). COX-2 activity was significantly increased in patients with BS compared to healthy subjects (p<0.05), but not COX-1 activity. Binary logistic regression analysis showed that sPLA2-IIA and PGE2 were independent factors predicting BSS severity. In conclusion, high level of sPLA2-IIA is associated with eicosanoid metabolism in patients with BSS.

Kidney-Detrimental Factors and Estimated Glomerular Filtration Rate in Preterm Newborns: The Role of Nutrition

: Background: Kidney function in preterm newborns may be impaired by many factors.

METHODS

71 newborns with gestational age (GA) < 32 weeks were enrolled. Serum creatinine (sCr), cystatin C (CysC), beta-trace protein (BTP) and urea were measured at T0 (3^rd day of life) and T36 (GA 36 weeks), and estimated glomerular filtration rate (eGFR) was calculated according to different formulas at T36. Pre-natal and post-natal kidney injury risk scores were calculated.

RESULTS

Newborns with GA ≤ 28 weeks had higher sCr at T0, and lower sCr, BTP and higher urea levels at T36 (p = 0.007, p = 0.005 and p = 0.029, respectively). eGFR values were not different according to GA when calculated by the formulas using only CysC, but were higher in subjects with GA ≤ 28 weeks according to the other formulas. The post-natal score was positively correlated with eGFR according to sCr-based formulas, but the correlations did not persist when adjusted for urea levels and GA.

CONCLUSIONS

CysC-based eGFR values are not influenced by GA. Post-natal score shows a direct correlation with eGFR according to sCr-based formulas, not persisting after adjustment for GA and urea levels, implying the importance of the nutritional status, since more premature subjects receive a more aggressive nutritional regimen, testified by higher urea levels.

Determination of neuroinflammatory biomarkers in autistic and neurotypical Saudi children

To identify neuroinflammatory biomarkers in patients with various severity of autism spectrum disorder (ASD) increases the insight about the pathogenesis and pathophysiology of this neurodevelopmental disorder. The aim of the present study was to analyze the levels in plasma of TGFβ2, Heat shock protein 70 (HSP70), and hematopoietic prostaglandin D2 synthase (H-PGDS) in Saudi ASD children and healthy age-matched neurotypical controls. Also, it was in the present study examined the correlation among these neuroinflammatory biomarkers and the sensory deficit exhibited by the ASD children. Blood samples from 38 Saudi children with ASD and 32 age-matched neurotypical controls were withdrawn after an overnight fast. For the blood taking 3 mL EDTA containing blood collection tubes was used. The samples were centrifuged for 20 min (4 °C; 3000×g) directly after the blood sampling. The harvested plasma was used for in vitro quantification of TGF-β2, HSP70, and H-PGDS by using the sandwich enzyme immunoassay. Receiver operating characteristic (ROC) analysis and predictiveness curves showed that each of TGF-β2, HSP70 or H-PGDS alone could not be used as a predictive neuroinflammatory biomarker for ASD. However, when TGF-β2 and HSP70 were combined in one ROC curve, the AUC was increased to an appreciable value that makes them together robust predictors of variation between the ASD and neurotypical control groups. Overall, it was in the present study found significant differences for TGF-β2 and HSP70 when the ASD and neurotypical control groups were compared, independently of the sensory deficit level. In conclusion, the present study highlights the usefulness of TGF-β2, HSP70, and H-PGDS as diagnostic tools to differentiate between ASD and neurotypical control children, but not among subgroups of ASD children exhibiting different severity levels of sensory dysfunction. The presented data also suggest the effectiveness of ROC as a powerful statistical tool, which precisely can measure a combined effect of neuroinflammatory biomarkers intended for diagnostic purposes.

Berberine and Pentoxifylline: A novel combination in amelioration of acute kidney injury

OBJECTIVE

To evaluate the nephro-protective effects of berberine and/or pentoxifylline on the reduction of diclofenac-induced acute kidney injury in rats.

METHODS

The experimental study was conducted at the Department of Pharmacology, College of Medicine, Mustansiriya University, Baghdad, Iraq, from February to April, 2018, and comprised fifty male Sprague-Dawley rats aged 3-4 months and weighing 250-400 grams each. They were divided into five equal groups and were treated for 12 days. Group 1 rats were treated with distilled water plus normal saline, Group 2 with distilled water plus diclofenac, Group 3 with berberine plus diclofenac, Group 4 with pentoxifylline plus diclofenac, and Group 5 rats were treated with berberine, pentoxifylline and diclofenac. Blood urea, creatinine, Neutrophil Gelatinase Associated Lipocalin (NGAL), kidney injury molecules (KIM-1) and cystatin-C were used to measure the severity of AKI.

RESULTS

Diclofenac led to significant AKI by significant elevation of blood urea, serum creatinine level, KIM-1, NGAL. Treatment with berberine showed no significant effect on all biomarkers level compared to diclofenac group except on serum KIM-1 level which was also seen in pentoxifylline group. Whereas, combination of berberine and pentoxifylline led to more significant effect in reduction of all renal biomarkers.

CONCLUSIONS

Combination of berberine with pentoxifylline led to more significant reno-protective than either berberine or pentoxifylline when used alone on diclofenac induced-AKI.

Estimation of GFR in children using rescaled beta-trace protein

INTRODUCTION

Beta-trace protein (BTP) is a low molecular weight protein, produced mainly in the cerebrospinal fluid. It has been proposed as a marker for kidney function. Recently, a new method for GFR estimation using mean normal values to rescale GFR marker concentrations has been described for creatinine and cystatin C, two commonly used endogenous markers for kidney function. The aim of this study is to apply this approach to BTP in children.

METHOD

We retrospectively analyzed serum concentrations of creatinine, cystatin C and BTP measured during inulin clearance tests in children. BTP was measured using a particle-enhanced immunonephelometric assay (Siemens Healthcare). A novel BTP-based eGFR equation was developed using published normal values for children: eGFR_BTP[ml/min/1.73m²] = 107.3/BTP/Q_BTP with Q_BTP = 0.69. Performance of this equation was compared to the established creatinine-based full age spectrum equation FASage and the cystatin C-based FAScys equations as well as the BTP-based Benlamri equation in terms of bias, % prediction error and P₃₀ and P₁₀ accuracy rates.

RESULTS

322 inulin clearance tests were studied. Overall, our novel equation performed comparably to the creatinine-based FASage and the BTP-based Benlamri equations but was less accurate than FAScys (P₃₀: 79.2 vs 86.3%, p = .008). Combining markers significantly enhanced performance compared to the single marker equations, with the exception of FAScys.

CONCLUSION

Rescaled BTP concentrations are a simple method for estimating GFR in children. However, the additional value of BTP for the estimation of GFR compared to rescaled creatinine and cystatin C still remains to be demonstrated.

Serum Beta-Trace Protein for Assessment of Kidney Function in Neonates

INTRODUCTION

Compared to the conventional methods, serum beta-trace protein (BTP) has been shown to be more helpful for estimating glomerular filtration rate; however, its value is remained unclear in neonates. The present study aimed to investigate the range of serum BTP level in healthy term neonates and its value to estimate glomerular filtration rate.

MATERIALS AND METHODS

This cross-sectional study was conducted on 50 healthy term neonates without underlying cardiovascular or kidney disorders who were admitted to Ali Asghar hospital in 2013. Serum BTP was measured using an automated nephelometric immunoassay. Glomerular filtration rate was assessed using the Schwartz equation based on serum creatinine level.

RESULTS

The mean age of the neonates was 6.2 ± 3.6 days (range, 2 to 17 days), their mean gestational age was 38.02 ± 0.20 weeks, and their mean height was 49.8 ± 1.7 cm. The mean serum BTP level was 0.41 ± 0.11 mg/L (range, 0.19 mg/L to 0.92 mg/L). The mean serum creatinine level was 0.49 ± 0.16 mg/dL (range, 0.3 mg/dL to 1.0 mg/dL). The mean estimated GFR was 48.90 ± 15.88 mL/min. A positive correlation was observed between the reciprocal concentrations of BTP and GFR (r = 0.383, P = .006). Furthermore, the reciprocal concentrations of BTP was associated with the reciprocal concentrations of serum creatinine level (r = 0.365, P = .009).

CONCLUSIONS

Measurement of serum BTP can be a reliable tool for detecting kidney function in neonates. Further studies are warranted to design a suitable formula for GFR estimation based on serum BTP in neonates.

Diagnosis of Allergy to Mammals and Fish: Cross-Reactive vs. Specific Markers

PURPOSE OF REVIEW

Allergen extracts are still widely used in allergy diagnosis as they are regarded as sensitive screening tools despite the fact that they may lack some minor allergens. Another drawback of extracts is their low specificity, which is due to the presence of cross-reactive allergens. Progress in allergen identification has disclosed a number of allergenic molecules of homologous sequence and structure which are present in different animal species. This review summarizes recent advances in mammalian and fish allergen identification and focuses on their clinical relevance.

RECENT FINDINGS

Serum albumins and parvalbumins are well-known animal panallergens. More recently several members of the lipocalin family were found to be cross-reactive between furry animals whereas in fish, additional allergens, enolase, aldolase and collagen, were found to be important and cross-reactive allergens. New epidemiological studies have analysed the prevalence and clinical relevance of mammalian and fish components. Primary sensitization can be distinguished from cross-sensitization by using marker allergens. Although substantial progress has been made in allergen identification, only few markers are commercially available for routine clinical practice.

Filtration Markers as Predictors of ESRD and Mortality: Individual Participant Data Meta-Analysis

BACKGROUND AND OBJECTIVES

Serum β-trace protein (BTP) and β-2 microglobulin (B2M) are associated with risk of ESRD and death in the general population and in populations at high risk for these outcomes (GP/HR) and those with CKD, but results differ among studies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed an individual patient-level meta-analysis including three GP/HR studies (n=17,903 participants) and three CKD studies (n=5415). We compared associations, risk prediction, and improvement in reclassification of eGFR using BTP (eGFRBTP) and B2M (eGFRB2M) alone and the average (eGFRavg) of eGFRBTP, eGFRB2M, creatinine (eGFRcr), and cystatin C (eGFRcys), to eGFRcr, eGFRcys, and their combination (eGFRcr-cys) for ESRD (2075 events) and death (7275 events).

RESULTS

Mean (SD) follow up times for ESRD and mortality for GP/HR and CKD studies were 13 (4), 6.2 (3.2), 14 (5), and 7.5 (3.9) years, respectively. Compared with eGFRcr, eGFRBTP and eGFRB2M improved risk associations and modestly improved prediction for ESRD and death even after adjustment for established risk factors. eGFRavg provided the most consistent improvement in associations and prediction across both outcomes and populations. Assessment of heterogeneity did not yield clinically relevant differences. For ESRD, addition of albuminuria substantially attenuated the improvement in risk prediction and risk classification with novel filtration markers. For mortality, addition of albuminuria did not affect the improvement in risk prediction with the use of novel markers, but lessened improvement in risk classification, especially for the CKD cohort.

CONCLUSIONS

These markers do not provide substantial additional prognostic information to eGFRcr and albuminuria, but may be appropriate in circumstances where eGFRcr is not accurate or albuminuria is not available. Educational efforts to increase measurement of albuminuria in clinical practice may be more cost-effective than measurement of BTP and B2M for improving prognostic information.

Can the new CKD-EPI BTP-B2M formula be applied in children?

Although measuring creatinine to determine kidney function is currently the clinical standard, new markers such as beta-trace protein (BTP) and beta-2-microglobulin (B2M) are being investigated in an effort to measure glomerular filtration rate more accurately. In their recent publication, Inker et al. (Am J Kidney Dis 2015; 67:40-48) explored the use of these two relatively new markers in combination with some commonly available clinical characteristics in a large cohort of adults with chronic kidney disease. Their research led them to develop three formulae using BTP, B2M, and a combination of the two. The combined formula is particularly attractive as it removes all gender bias, which applies to both serum creatinine and cystatin C. Using data from a cohort of 127 pediatric patients from our center, we sought to determine whether these formulae would be equally as effective in children as in adults. Unfortunately, we found that the formulae cannot be applied to the pediatric population.

Non-GFR Determinants of Low-Molecular-Weight Serum Protein Filtration Markers in CKD

BACKGROUND

Unlike the case with creatinine, conditions affecting the non-glomerular filtration rate (GFR) determinants of low-molecular-weight serum proteins, β-trace protein (BTP), β2-microglobulin (B2M), and cystatin C, are not well characterized.

STUDY DESIGN

Pooled cross-sectional analysis of 3 studies.

SETTING & PARTICIPANTS

3,156 persons with chronic kidney disease from the MDRD (Modification of Diet in Renal Disease) Study, AASK (African American Study of Kidney Disease and Hypertension), and CRIC (Chronic Renal Insufficiency Cohort) Study.

PREDICTORS

Demographic and clinical factors hypothesized to be associated with non-GFR determinants of the filtration markers, selected from literature review and physiologic and clinical considerations.

OUTCOMES

Serum creatinine, BTP, B2M, and cystatin C levels.

RESULTS

In multivariable-adjusted errors-in-variables regression models that included adjustment for measured GFR (mGFR) and mGFR measurement error, creatinine level had stronger associations with male sex, black race, and higher urine creatinine excretion than the other filtration markers. BTP was associated less strongly with age, similar in direction with sex, and opposite in direction with race than creatinine level. Like cystatin C, B2M level was associated less strongly with age, sex, and race than creatinine level. BTP, B2M, and cystatin C levels were associated more strongly than creatinine level with other factors, including urine protein excretion and weight for BTP, smoking and urine protein excretion for B2M, and smoking for cystatin C.

LIMITATIONS

Findings may not be generalizable to populations without chronic kidney disease, and residual confounding with GFR due to incomplete adjustment for GFR measurement error.

CONCLUSIONS

Like creatinine, serum levels of low-molecular-weight proteins are affected by conditions other than GFR. Knowledge of these conditions can aid the interpretation of GFR estimates and risk using these markers and guide the use of these filtration markers in developing GFR estimating equations.

Serum Chemerin Levels Are Associated with Abdominal Visceral Fat in Type 2 Diabetes

Chemerin is a recently identified adipokine suggested to play a role in obesity and its metabolic complications. The relationship between visceral obesity and serum chemerin levels in type 2 diabetes (T2DM) is unknown and may differ from that of subjects without diabetes. Therefore, we evaluated whether serum chemerin was associated with visceral abdominal obesity in patients with T2DM. A total of 218 Korean patients with T2DM were enrolled and metabolic parameters, abdominal visceral and subcutaneous fat areas, and serum chemerin levels were measured. Serum chemerin level showed positive correlation with fasting insulin, HOMA-IR, serum triglyceride, serum creatinine, urine albumin/creatinine ratio, high-sensitivity C-reactive protein (hsCRP), fibrinogen, abdominal visceral fat area, visceral to subcutaneous fat area ratio, and negatively correlation with high density lipoprotein cholesterol and creatinine clearance (CCr) after adjusting for age, gender and body mass index. Multiple linear stepwise regression analysis showed that abdominal visceral fat area (β = 0.001, P < 0.001), serum triglyceride (β = 0.001, P < 0.001), CCr (β = -0.003, P = 0.001), hsCRP (β = 0.157, P = 0.001), fibrinogen (β = 0.001, P < 0.001) and BMI (β = 0.02, P = 0.008) independently affected log transformed serum chemerin levels. Higher serum chemerin level was associated with higher level of abdominal visceral fat area, serum triglyceride, hsCRP and fibrinogen and lower level of CCr in patients with T2DM. Serum chemerin may be used as a biomarker of visceral adiposity and chemerin may play a role in inflammation, decreased renal function, and increased cardiovascular risk in T2DM.

Effect of Early vs Delayed Initiation of Renal Replacement Therapy on Mortality in Critically Ill Patients With Acute Kidney Injury: The ELAIN Randomized Clinical Trial

IMPORTANCE

Optimal timing of initiation of renal replacement therapy (RRT) for severe acute kidney injury (AKI) but without life-threatening indications is still unknown.

OBJECTIVE

To determine whether early initiation of RRT in patients who are critically ill with AKI reduces 90-day all-cause mortality.

DESIGN, SETTING, AND PARTICIPANTS

Single-center randomized clinical trial of 231 critically ill patients with AKI Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 (≥2 times baseline or urinary output <0.5 mL/kg/h for ≥12 hours) and plasma neutrophil gelatinase-associated lipocalin level higher than 150 ng/mL enrolled between August 2013 and June 2015 from a university hospital in Germany.

INTERVENTIONS

Early (within 8 hours of diagnosis of KDIGO stage 2; n = 112) or delayed (within 12 hours of stage 3 AKI or no initiation; n = 119) initiation of RRT.

MAIN OUTCOMES AND MEASURES

The primary end point was mortality at 90 days after randomization. Secondary end points included 28- and 60-day mortality, clinical evidence of organ dysfunction, recovery of renal function, requirement of RRT after day 90, duration of renal support, and intensive care unit (ICU) and hospital length of stay.

RESULTS

Among 231 patients (mean age, 67 years; men, 146 [63.2%]), all patients in the early group (n = 112) and 108 of 119 patients (90.8%) in the delayed group received RRT. All patients completed follow-up at 90 days. Median time (Q1, Q3) from meeting full eligibility criteria to RRT initiation was significantly shorter in the early group (6.0 hours [Q1, Q3: 4.0, 7.0]) than in the delayed group (25.5 h [Q1, Q3: 18.8, 40.3]; difference, -21.0 [95% CI, -24.0 to -18.0]; P < .001). Early initiation of RRT significantly reduced 90-day mortality (44 of 112 patients [39.3%]) compared with delayed initiation of RRT (65 of 119 patients [54.7%]; hazard ratio [HR], 0.66 [95% CI, 0.45 to 0.97]; difference, -15.4% [95% CI, -28.1% to -2.6%]; P = .03). More patients in the early group recovered renal function by day 90 (60 of 112 patients [53.6%] in the early group vs 46 of 119 patients [38.7%] in the delayed group; odds ratio [OR], 0.55 [95% CI, 0.32 to 0. 93]; difference, 14.9% [95% CI, 2.2% to 27.6%]; P = .02). Duration of RRT and length of hospital stay were significantly shorter in the early group than in the delayed group (RRT: 9 days [Q1, Q3: 4, 44] in the early group vs 25 days [Q1, Q3: 7, >90] in the delayed group; P = .04; HR, 0.69 [95% CI, 0.48 to 1.00]; difference, -18 days [95% CI, -41 to 4]; hospital stay: 51 days [Q1, Q3: 31, 74] in the early group vs 82 days [Q1, Q3: 67, >90] in the delayed group; P < .001; HR, 0.34 [95% CI, 0.22 to 0.52]; difference, -37 days [95% CI, -∞ to -19.5]), but there was no significant effect on requirement of RRT after day 90, organ dysfunction, and length of ICU stay.

CONCLUSIONS AND RELEVANCE

Among critically ill patients with AKI, early RRT compared with delayed initiation of RRT reduced mortality over the first 90 days. Further multicenter trials of this intervention are warranted.

TRIAL REGISTRATION

German Clinical Trial Registry Identifier: DRKS00004367.

Reference intervals for renal injury biomarkers neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in young infants

BACKGROUND

Reliable reference intervals for two novel urinary biomarkers of renal injury, neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) are lacking for infants. Therefore, the aim of our study was to establish reference intervals for urinary NGAL and KIM-1 absolute concentrations as well as normalized to urinary creatinine in young infants categorized in small age intervals.

METHODS

From June 2010 to March 2014, serum and urine samples of 106 basically healthy infants (born between 37 and 42 weeks of gestation) aged 1 day to 1 year were collected. Blood samples were assayed for serum creatinine levels to confirm a healthy renal status. Urine samples were assayed for creatinine, uNGAL (ng/mL) and uKIM-1 (ng/mL).

RESULTS

Two thirds of the study cohort were boys. uNGAL concentrations declined with increasing age (likelihood ratio test, p=0.001). Also, uNGAL concentrations were higher in girls (50th centile uNGAL was 27.1 ng/mL) than boys (50th centile uNGAL was 14.3 ng/mL) (two tailed Wald test, p<0.001) NGAL concentrations were not related to ethnicity. uKIM-1 concentrations were extremely low in almost all 106 subjects [median uKIM-1 was 0.08 (IQR 0.08-0.08) ng/mL] and not related with age, gender or ethnicity (all p>0.05).

CONCLUSIONS

Our data uniquely provide uNGAL and uKIM-1 reference intervals for the first year of life. Notably, only uNGAL levels decreased with increasing age and were higher in girls. These reference intervals enable future studies to evaluate the performance of both biomarkers in detecting early kidney tubular injury, particularly in the setting of critical care.

Serum Neutrophil Gelatinase-Associated Lipocalin and Cystatin C for Assessing Recovery of Graft Function in Patients Undergoing Living-Donor Kidney Transplantation

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) can be used as an early indicator of acute kidney injury (AKI), and cystatin C is also suggested to be an ideal marker of glomerular filtration rate (GFR), but they were not sufficiently studied in recipients without delayed graft function (DGF) after living-donor kidney transplant (LDKT). The aim of the study is to investigate whether serum NGAL and cystatin C can assess the recovery of renal function after LDKT.

METHODS

49 adult patients that had undergone LDKT between January 2012 and March 2014 were prospectively enrolled. Serum creatinine, NGAL, and cystatin C were measured on day 0-7, day 10, day 14 and month 9 after transplant. Recovery of graft function was evaluated by the time needed to reach eGFR > or = 60 mL/min/1.73 in2 Poor long-term graft outcome was defined as eGFR < 60 mL/min/1.73 M2 at 9 months.

RESULTS

No DGF was recorded. Serum NGAL level decreased to normal earlier than creatinine after transplant. Cystatin C declined rapidly, but still stayed above the normal range. Serum NGAL on day 0 (p = 0.028) and cystatin C on day 2 (p < 0.001) were independent predictors of the time for graft function recovery in multivariate analysis. Compared to recipients with fair long-term graft outcome (eGFR > 60 mL/min/1.73 m2 at 9 months), recipients with poor long-term graft outcome (eGFR < 60 mL/min/1.73 m2 at 9 months) displayed higher serum NGAL on day 2 (p = 0.045), older age (p = 0.002), longer time on dialysis (p = 0.02), and lower donor eGFR (p = 0.045). There were correlations between serum NGAL and eGFR on day 0 and day 2. Correlations between serum cystatin C and eGFR on day 0, day 2, and month 9 were all significant.

CONCLUSIONS

Serum NGAL may be used as an early predictor of recovery of post-transplant graft function after LDKT, but may not be used for real-time assessment of GFR. At the same time, the predictive ability of serum cystatin C needs to be further assessed.

Plasma levels of neutrophil gelatinase-associated lipocalin in children with heart failure

INTRODUCTION

Data about plasma levels of neutrophil gelatinase-associated lipocalin (NGAL) in children with heart failure (HF) are very limited. NGAL is used widely as a biomarker for the diagnosis of renal injury in numerous clinical studies. The aim of this study is to investigate the plasma NGAL in children with HF caused by idiopathic dilated cardiomyopathy (IDCM) and its relation to the severity of HF.

MATERIAL AND METHODS

In a case-control study, 30 nondiabetic children, aged -16 years (all have IDCM) recruited from the pediatric department of our institute together with 30 healthy children were prospectively enrolled in this study. Patients underwent a detailed history taking, clinical examination, New York Heart Association (NYHA) class assessment and echocardiographic evaluation. Plasma levels of NGAL were measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma levels of NGAL were significantly higher in children with HF compared with healthy controls (mean: 290.97 versus 144.33, p < 0.0001). The relationship between NGAL and the severity of HF was investigated. However, we did not find any statistically significant relationship between plasma NGAL levels and indices of myocardial function.

CONCLUSIONS

NGAL levels were significantly increased in children with HF caused by IDCM. However, there was no significant relationship between plasma NGAL levels and indices of myocardial function. Future multicenter clinical studies in a large population addressing the natural course of NGAL in HF and its potential as a treatment target are needed in the near future.

Short-Term Regulation of Lipocalin-2 but not RBP-4 During Oral Lipid Tolerance Test and Oral Glucose Tolerance Test

The postprandial regulation of lipocalin-2 and retinol binding protein-4 (RBP-4) by oral uptake of lipids and carbohydrates in healthy individuals has not yet been investigated. The regulation of lipocalin-2 and RBP-4 in 2 large cohorts of healthy volunteers during oral lipid tolerance test (OLTT; n=100) and oral glucose tolerance test (OGTT; n=100) was analyzed. One hundred healthy volunteers underwent OLTT and OGTT in an outpatient setting. Venous blood was drawn after 0, 2, 4, and 6 h in OLTT and after 0, 1, and 2 h in OGTT. In order to dissect carbohydrate-induced from lipid-induced effects, a novel OLTT solution completely free of carbohydrates and protein was applied. Subjects were characterized by anthropometric and laboratory parameters. Serum concentrations of lipocalin-2 and RBP-4 were measured by enzyme-linked immunosorbent assay (ELISA). Whereas RBP-4 levels remained unchanged during OGTT, lipocalin-2 concentrations significantly decreased during OGTT. During OLTT, RBP-4 levels were not influenced, whereas lipocalin-2 levels decreased significantly and stepwise. Fasting concentrations of RBP-4 were negatively correlated with BMI and waist-hip ratio, whereas lipocalin-2 levels were positively associated with BMI and waist-hip ratio. Female users of hormonal contraception had higher RBP-4 levels than females not on contraceptives. There is no significant short-term regulation of RBP-4 by orally ingested lipids or carbohydrates. Lipocalin-2 is downregulated after lipid and carbohydrate ingestion and this kind of regulation was not predicted by age, sex, triglycerides, glucose, or insulin levels.

Timing of renal replacement therapy in acute kidney injury

Acute kidney injury (AKI) is a frequent finding in patients with critical illness. In many of these patients renal replacement therapy (RRT) is needed to support organ dysfunction. Although international guidelines on the management of AKI have been developed and are widely accepted, there is still considerable controversy on the optimal timing of RRT. The clinician is in a constant dilemma that level of evidence (on timing of acute RRT) is low and the issue is of high importance. Despite this paucity of high quality prospective data, this review will give the reader an idea on how to approach the difficult question of initiating RRT. Obviously, no general recommendation can be given covering every aspect of intensive care medicine. Therefore, general thoughts are displayed, followed by a focus on specific clinical situations. The role of "novel" biomarkers in the process of deciding when to start is also discussed.

Effects of Traumatic Amputation on β-Trace Protein and β2-Microglobulin Concentrations in Male Soldiers

BACKGROUND

Serum creatinine (SCr) levels are decreased following traumatic amputation, leading to the overestimation of glomerular filtration rate (GFR). β-Trace protein (BTP) and β2-microglobulin (B2M) strongly correlate with measured GFR and have not been studied following amputation. We hypothesized that BTP and B2M would be unaffected by traumatic amputation.

METHODS

We used the Department of Defense Serum Repository to compare pre- and post-traumatic amputation serum BTP and B2M levels in 33 male soldiers, via the N Latex BTP and B2M nephelometric assays (Siemens Diagnostics, Tarrytown, N.Y., USA). Osterkamp estimation using DEXA scan measurements was used to establish percent estimated body weight loss (%EBWL). Results were analyzed for small (3-5.9% EBWL), medium (6-13.5%), and large (>13.5%) amputation subgroups; and for a control group matched 1:1 to the 12 large amputation subjects. Paired Student's t test was used for comparisons.

RESULTS

Mean serum BTP levels were unchanged in controls, all amputees, and the small and medium amputation subgroups. BTP appeared to decrease following large %EBWL amputation (p = 0.05). Mean serum B2M levels were unchanged in controls, all amputees, and the small and medium amputation subgroups. B2M appeared to increase following large %EBWL amputation (p = 0.05).

CONCLUSIONS

BTP and B2M levels are less affected than SCr by amputation, and should be considered for future study of GFR estimation. BTP and B2M changes following large %EBWL amputation require validation and may offer insight into non-GFR BTP and B2M determinants as well as increased cardiovascular disease and mortality following amputation.

Klotho and S100A8/A9 as Discriminative Markers between Pre-Renal and Intrinsic Acute Kidney Injury

Early detection and accurate differentiation of the cause of AKI may improve the prognosis of the patient. However, to date, there are few reliable biomarkers that can discriminate between pre-renal and intrinsic AKI. In this study, we determined whether AKI is associated with altered serum and urinary levels of Klotho, S100A8/A9 (an endogenous ligand of toll-like receptor 4), and neutrophil gelatinase-associated lipocalin (NGAL), which may allow differentiation between pre-renal and intrinsic AKI. A volume-depleted pre-renal AKI model was induced in male Sprague Dawley rats fed a low-salt diet (0.03%) without water 96 h before two intraperitoneal (IP) injections of furosemide (20 mg/kg) at a 24 h interval. In contrast, in the cisplatin-induced intrinsic AKI model, animals were given a single IP injection of cisplatin (5 mg/kg). All of the animals were euthanized 72 h after the first IP injection. Serum and urinary levels of Klotho, S100A8/A9, and NGAL were measured using an enzyme-linked immunosorbent assay. We also performed a proof-of-concept cross-sectional study to measure serum and urinary biomarkers in 61 hospitalized patients with established AKI. Compared to the intrinsic AKI group, the pre-renal AKI group showed a marked depression in urinary Klotho levels (13.21±17.32 vs. 72.97±17.96 pg/mL; P = 0.002). In addition, the intrinsic AKI group showed marked elevation of S100A8/A9 levels compared to the pre-renal AKI group (2629.97±598.05 ng/mL vs. 685.09±111.65 ng/mL; P = 0.002 in serum; 3361.11±250.86 ng/mL vs. 741.72±101.96 ng/mL; P = 0.003 in urine). There was no difference in serum and urinary NGAL levels between the pre-renal and intrinsic AKI groups. The proof-of-concept study with the hospitalized AKI patients also demonstrated decreased urinary Klotho in pre-renal AKI patients and increased urinary S100A8/A9 concentrations in intrinsic AKI patients. The attenuation of urinary Klotho and increase in urinary S100A8/A9 may allow differentiation between pre-renal and intrinsic AKI.

Effects of Serum Uric Acid on Estimated GFR in Cardiac Surgery Patients: A Pilot Study

BACKGROUND

The aim of the study was to investigate the effects of serum uric acid (SUA) on acute kidney injury (AKI) in patients undergoing cardiac surgery.

METHODS

Prospectively collected data from a previous study were analyzed to investigate the relationship between SUA and AKI as assessed by neutrophil gelatinase-associated lipocalin (NGAL), serum creatinine (SCr) and kinetic estimated glomerular filtration rate (KeGFR).

RESULTS

Patients undergoing cardiovascular surgery (n = 37) were included. SUA was measured at postoperative 1 h. Statistically significant correlations were present between SUA and NGAL measured at postoperative 1 h (r = 0.39, p = 0.008), 6 h (r = 0.31, p = 0.029) and 24 h (r = 0.31, p < 0.001), respectively. Significant correlations were also noted between SUA and SCr measured on postoperative day 1 (r = 0.41, p = 0.006), day 2 (r = 0.29, p = 0.042) and day 3 (r = 0.42, p = 0.009). Negative correlations were demonstrated between SUA and day 1 (r = -0.44, p = 0.007), day 2 (r = -0.43, p = 0.007), day 3 (r = -0.44, p = 0.006 and day 4 KeGFR (r = -0.35, p = 0.035). The inverse relationship of SUA and KeGFR was also demonstrated with a different method (Jelliffe) of measurement.

CONCLUSIONS

A reduction in glomerular filtration rate (GFR) can lead to a rise in SUA. However, in this study, we are able to show that SUA at 1 h (maximal dilution time) effectively predicts subsequent changes in urinary NGAL, SCr, KeGFR, and the development of AKI. Thus, these findings suggest that uric acid precedes and predicts acute changes in renal function and cannot be ascribed to a simple relationship in which a reduced GFR raises SUA.

GFR Estimation Using β-Trace Protein and β2-Microglobulin in CKD

BACKGROUND

β-Trace protein (BTP) and β2-microglobulin (B2M) are novel glomerular filtration markers that have stronger associations with adverse outcomes than creatinine. Comparisons of BTP and B2M to creatinine and cystatin C are limited by the absence of rigorously developed glomerular filtration rate (GFR) estimating equations for the novel markers.

STUDY DESIGN

Study of diagnostic test accuracy.

SETTING & PARTICIPANTS

Pooled database of 3 populations with chronic kidney disease (CKD) with mean measured GFR of 48 mL/min/1.73 m2 (N=3,551; MDRD [Modification of Diet in Renal Disease] Study, AASK [African American Study of Kidney Disease and Hypertension], and CRIC [Chronic Renal Insufficiency Cohort] Study).

INDEX TESTS

GFR estimated using creatinine, cystatin C, BTP, or B2M level.

REFERENCE TEST

GFR measured as the urinary clearance of iothalamate.

RESULTS

For BTP and B2M, coefficients for age, sex, and race were smaller than for creatinine and were similar or smaller than for cystatin C. For B2M, coefficients for sex, age, and race were smaller than for creatinine and were similar (age and race) or smaller (sex) than for cystatin C. The final equations with BTP (BTP, age, and sex) or B2M (B2M alone) were less accurate than either the CKD-EPI (CKD Epidemiology Collaboration) creatinine or cystatin C equations. The combined BTP-B2M equation (BTP and B2M alone) had similar accuracy to the CKD-EPI creatinine or cystatin C equation. The average of the BTP-B2M equation and the CKD-EPI creatinine-cystatin C equation was not more accurate than the CKD-EPI creatinine-cystatin C equation.

LIMITATIONS

No external validation population, study population was restricted to CKD, few participants older than 65 years, or nonblack nonwhite race.

CONCLUSIONS

BTP and B2M are less influenced by age, sex, and race than creatinine and less influenced by race than cystatin C, but provide less accurate GFR estimates than the CKD-EPI creatinine and cystatin C equations. The CKD-EPI BTP and B2M equation provides a methodological advance for their study as filtration markers and in their associations with risk and adverse outcomes, but further study is required before clinical use.

Neutrophil Gelatinase Associated Lipocalin (NGAL) in Leptospirosis Acute Kidney Injury: A Multicenter Study in Thailand

AKI is one of the most serious complications of leptospirosis, an important zoonosis in the tropics. Recently, NGAL, one of the novel AKI biomarkers, is extensively studied in various specific settings such as sepsis, cardiac surgery, and radiocontrast nephropathy. In this multicenter study, we aimed to study the role of NGAL as an early marker and an outcome predictor of leptospirosis associated AKI. Patients who presented with clinical suspiciousness of leptospirosis were prospectively enrolled in 9 centers from August 2012 to November 2014. The first day of enrollment was the first day of clinical suspicious leptospirosis. Blood and urine samples were serially collected on the first three days and day 7 after enrollment. We used three standard techniques (microscopic agglutination test, direct culture, and PCR technique) to confirm the diagnosis of leptospirosis. KDIGO criteria were used for AKI diagnosis. Recovery was defined as alive and not requiring dialysis during hospitalization or maintaining maximum KDIGO stage at hospital discharge. Of the 221 recruited cases, 113 cases were leptospirosis confirmed cases. Thirty seven percent developed AKI. Median uNGAL and pNGAL levels in those developing AKI were significantly higher than in patients not developing AKI [253.8 (631.4) vs 24.1 (49.6) ng/ml, p < 0.001] and [1,030 (802.5) vs 192.0 (209.0) ng/ml, p < 0.001], respectively. uNGAL and pNGAL levels associated with AKI had AUC-ROC of 0.91, and 0.92, respectively. Both of urine NGAL and pNGAL level between AKI-recovery group and AKI-non recovery were comparable. From this multicenter study, uNGAL and pNGAL provided the promising result to be a marker for leptospirosis associated AKI. However, both of them did not show the potential role to be the predictor of renal recovery in this specific setting.

Value of plasma neutrophil gelatinase-associated lipocalin in predicting the mortality of patients with sepsis at the emergency department

BACKGROUND

Sepsis is a major cause of morbidity and mortality in the emergency department. This study aimed to evaluate the assessment of severity of sepsis by and prognostic value of plasma neutrophil gelatinase-associated lipocalin (NGAL) compared with other widely used biological markers of inflammation in patients with sepsis.

METHODS

NGAL, procalcitonin, and C-reactive protein values were measured in 470 patients with suspected sepsis, and the Mortality in Emergency Department Sepsis (MEDS) score was obtained for all enrolled subjects, who were followed for up to 28days.

RESULTS

The median plasma NGAL value was increased with sepsis severity according to the MEDS score. The plasma NGAL value was higher in nonsurvivors than in survivors. The area under the receiver operating characteristic curve of NGAL (0.797) was greater than that of procalcitonin (0.599) and MEDS score (0.774) in predicting 28-day hospital mortality. Multivariable logistic regression found that the plasma NGAL value was an independent predictor for hospital mortality in patients with sepsis. The plasma NGAL values were positively correlated with C-reactive protein and procalcitonin levels, and MEDS scores.

CONCLUSIONS

Plasma NGAL is a valuable biological marker in the assessment of severity and prediction of prognosis of patients with sepsis in the emergency department.

Comparison between admission natriuretic peptides, NGAL and sST2 testing for the prediction of worsening renal function in patients with acutely decompensated heart failure

BACKGROUND

In order to predict the occurrence of worsening renal function (WRF) and of WRF plus in-hospital death, 101 emergency department (ED) patients with acute decompensated heart failure (ADHF) were evaluated with testing for amino-terminal pro-B-type natriuretic peptide (NT-proBNP), BNP, sST2, and neutrophil gelatinase associated lipocalin (NGAL).

METHODS

In a prospective international study, biomarkers were collected at the time of admission; the occurrence of subsequent in hospital WRF was evaluated.

RESULTS

In total 26% of patients developed WRF. Compared to patients without WRF, those with WRF had a longer in-hospital length of stay (LOS) (mean LOS 13.1±13.4 days vs. 4.8±3.7 days, p<0.001) and higher in-hospital mortality [6/26 (23%) vs. 2/75 (2.6%), p<0.001]. Among the biomarkers assessed, baseline NT-proBNP (4846 vs. 3024 pg/mL; p=0.04), BNP (609 vs. 435 pg/mL; p=0.05) and NGAL (234 vs. 174 pg/mL; p=0.05) were each higher in those who developed WRF. In logistic regression, the combination of elevated natriuretic peptide and NGAL were additively predictive for WRF (ORNT-proBNP+NGAL=2.79; ORBNP+NGAL=3.11; both p<0.04). Rates of WRF were considerably higher in patients with elevation of both classes of biomarker. Comparable results were observed in a separate cohort of 162 patients with ADHF from a different center.

CONCLUSIONS

In ED patients with ADHF, the combination of NT-proBNP or BNP plus NGAL at presentation may be useful to predict impending WRF (Clinicaltrials.gov NCT#0150153).

Prognostic impact of neutrophil gelatinase-associated lipocalin and B-type natriuretic in patients with ST-elevation myocardial infarction treated by primary PCI: a prospective observational cohort study

OBJECTIVES

Neutrophil gelatinase-associated lipocalin (NGAL) from a pathophysiological perspective connects various pathways that affect the prognosis after myocardial infarction. The objective was to evaluate the benefits of measuring NGAL for prognostic stratification in addition to the Thrombolysis in Myocardial Infarction (TIMI) score, and to compare it with the prognostic value of B-type natriuretic peptide (BNP).

DESIGN

Prospective observational cohort study.

SETTING

One university/tertiary centre.

PARTICIPANTS

A total of 673 patients with ST segment elevation myocardial infarction were treated by primary percutaneous coronary intervention. NGAL and BNP were assessed on hospital admission.

PRIMARY OUTCOME

1-year mortality.

SECONDARY OUTCOMES

1-year hospitalisation due to acute heart failure, unplanned revascularisation, reinfarction, stroke and combined end point of 1-year mortality and hospitalisation due to heart failure.

STATISTICAL METHODS

Using the c-statistic, the ability of NGAL, BNP and TIMI score to predict 1-year mortality alone and in combination with readmission for heart failure was evaluated. The addition of the predictive value of biomarkers to the score was assessed by category free net reclassification improvement (cfNRI) and the integrated discrimination index (IDI).

RESULTS

The NGAL level was significantly higher in non-survivors (67 vs 115 pg/mL; p<0.001). The area under the curve (AUC) values for mortality prediction for NGAL, BNP and TIMI score were 75.5, 78.7 and 74.4, respectively (all p<0.001) with optimal cut-off values of 84 pg/mL for NGAL and 150 pg/mL for BNP. The addition of NGAL and BNP to the TIMI score significantly improved risk stratification according to cfNRI and IDI. A BNP and the combination of the TIMI score with NGAL predicted the occurrence of the combined end point with an AUC of 80.6 or 82.2, respectively. NGAL alone is a simple tool to identify very high-risk patients. NGAL >110 pg/mL was associated with a 1-year mortality of 20%.

CONCLUSIONS

The measurement of NGAL together with the TIMI score results in a strong prognostic model for the 1-year mortality rate in patients with STEMI.

Lipocalin-2 Is a Disease Activity Marker in Inflammatory Bowel Disease Regulated by IL-17A, IL-22, and TNF-α and Modulated by IL23R Genotype Status

BACKGROUND

Lipocalin-2 (LCN2) is a potent bacteriostatic protein. We aimed to investigate its role as a disease activity marker in patients with inflammatory bowel disease (IBD) and its induction by the Th17 cytokines IL-17A, IL-22, and TNF-α in colonic epithelial cells. Moreover, we analyzed the influence of IBD-associated IL23R alleles on LCN2 serum levels in IBD patients.

METHODS

LCN2 serum levels were determined in 131 IBD patients (71 with Crohn's disease [CD], 60 with ulcerative colitis [UC]) and 63 healthy controls. IBD patients were genotyped for 10 IBD-associated IL23R polymorphisms. LCN2 expression after stimulation with IL-17A, IL-22, and TNF-α was measured in human colonic epithelial cell lines.

RESULTS

A significant upregulation of serum LCN2 in active IBD (median [IQR], 36.84 [21.17-73.74] ng/mL; P = 0.01) compared with healthy controls (24.22 [17.76-35.25] ng/mL) was confined to active UC (42.21 [28.97-73.74] ng/mL; P = 0.0006). LCN2 proved to be a marker of UC disease activity (area under the curve 0.75, sensitivity 0.83, specificity 0.63; P = 0.0002). IL-17A showed a synergistic effect with IL-22 and TNF-α in inducing colonic epithelial expression of LCN2 and its essential transcription factor IKBZ. In CD, LCN2 concentrations were significantly modulated by IL23R genotype status with homozygous carriers of IBD risk-increasing alleles showing particularly low LCN2 levels.

CONCLUSIONS

Serum LCN2 proves to be a biomarker of active UC. Lower LCN2 levels in CD patients carrying IBD risk-increasing IL23R variants may result from a restricted upregulation of LCN2 due to an impaired Th17 immune response.

Balanced Hydroxyethylstarch (HES 130/0.4) Impairs Kidney Function In-Vivo without Inflammation

Volume therapy is a standard procedure in daily perioperative care, and there is an ongoing discussion about the benefits of colloid resuscitation with hydroxyethylstarch (HES). In sepsis HES should be avoided due to a higher risk for acute kidney injury (AKI). Results of the usage of HES in patients without sepsis are controversial. Therefore we conducted an animal study to evaluate the impact of 6% HES 130/0.4 on kidney integrity with sepsis or under healthy conditions Sepsis was induced by standardized Colon Ascendens Stent Peritonitis (sCASP). sCASP-group as well as control group (C) remained untreated for 24 h. After 18 h sCASP+HES group (sCASP+VOL) and control+HES (C+VOL) received 50 ml/KG balanced 6% HES (VOL) 130/0.4 over 6 h. After 24 h kidney function was measured via Inulin- and PAH-Clearance in re-anesthetized rats, and serum urea, creatinine (crea), cystatin C and Neutrophil gelatinase-associated lipocalin (NGAL) as well as histopathology were analysed. In vitro human proximal tubule cells (PTC) were cultured +/- lipopolysaccharid (LPS) and with 0.1-4.0% VOL. Cell viability was measured with XTT-, cell toxicity with LDH-test. sCASP induced severe septic AKI demonstrated divergent results regarding renal function by clearance or creatinine measure focusing on VOL. Soleley HES (C+VOL) deteriorated renal function without sCASP. Histopathology revealed significantly derangements in all HES groups compared to control. In vitro LPS did not worsen the HES induced reduction of cell viability in PTC cells. For the first time, we demonstrated, that application of 50 ml/KG 6% HES 130/0.4 over 6 hours induced AKI without inflammation in vivo. Severity of sCASP induced septic AKI might be no longer susceptible to the way of volume expansion.

Neutrophil Gelatinase-associated Lipocalin in the Prediction of Contrast-induced Nephropathy: A Systemic Review and Meta-analysis

OBJECTIVE

The aim of this study was to investigate the predictive value of neutrophil gelatinase-associated lipocalin (NGAL) in the early diagnosis of contrast-induced nephropathy (CIN).

METHODS

We searched MEDLINE and Embase until December 2014 for articles evaluating the diagnostic accuracy of plasma/serum and urinary NGAL levels to predict CIN. The primary analysis was based on a hierarchical, bivariate, generalized, linear, mixed model. Diagnostic odds ratio (DOR) and sample size-weighted area under the curve for the receiver operating characteristic (AUROC) were calculated.

RESULTS

Ten studies involving 1310 patients were analyzed. Overall, the DOR/AUROC for NGAL level to predict CIN was 20.56 [95% confidence interval (CI), 9.67-43.74]/0.87 (95% CI, 0.84-0.90), with sensitivity and specificity of 0.80 (95% CI, 0.74-0.85) and 0.83 (95% CI, 0.73-0.90), respectively. Subgroup analysis showed that the diagnostic performance of the DOR/AUROC of urinary NGAL [29.48 (95% CI, 12.19-71.27)/0.87 (95% CI, 0.84-0.90)] was better than that of plasma/serum NGAL [14.63 (95% CI, 4.51-47.38)/0.85 (95% CI, 0.82-0.88)] (DOR, P = 0.005, and AUROC, P = 0.04, respectively).

CONCLUSIONS

Plasma/serum and urinary NGAL levels seem to be useful biomarkers in the early prediction of CIN. Moreover, urinary NGAL levels perform better than plasma/serum NGAL.

Cardiorenal syndrome type 5: in vitro cytotoxicity effects on renal tubular cells and inflammatory profile

Background. Cardiorenal Syndrome Type 5 (CRS Type 5) reflects concomitant cardiac and renal dysfunctions in the setting of a wide spectrum of systemic disorders. Our aim was to study in vitro effects of CRS Type 5 plasma on renal tubular cells (RTCs), in terms of cellular death and the characterization of inflammatory plasma profile in these patients. Material and Methods. We enrolled 11 CRS Type 5 patients from ICU and 16 healthy controls. Plasma from patients and controls was incubated with renal tubular cells (RTCs) and cell death was evaluated. Plasma cytokines were detected. Results. RTCs incubated with CRS Type 5 plasma showed significantly higher apoptosis and necrosis with respect to controls. Plasma cytokine profile of CRS Type 5 patients was significantly different from controls: we observed the production of pro- and anti-inflammatory mediators in these patients. Caspase-3, caspase-8, and caspase-9 were activated in cells treated with CRS Type 5 plasma compared to controls. Conclusions. Our results underline the cytotoxic effect of CRS Type 5 mediators on RTC viability, probably due to the activation of both intrinsic and extrinsic pathways of apoptosis and to the deregulation of cytokine release. The consequence may be the damage of distant organs which lead to the worsening of condition of patients.

Low Serum Neutrophil Gelatinase-associated Lipocalin Level as a Marker of Malnutrition in Maintenance Hemodialysis Patients

Background

Neutrophil gelatinase-associated lipocalin (NGAL or LCN2) is an iron-transporting factor which possesses various activities such as amelioration of kidney injury and host defense against pathogens. Its circulating concentrations are elevated in acute and chronic kidney diseases and show a positive correlation with poor renal outcome and mortality, but its clinical significance in maintenance hemodialysis (HD) patients remains elusive.

Methods

Serum NGAL levels were determined by enzyme-linked immunosorbent assay in out-patient, Japanese HD subjects. Their correlation to laboratory findings and morbidity (as development of severe infection or serum albumin reduction) was investigated using linear regression analysis and χ² test.

Results

Pre-dialysis serum NGAL levels in HD patients were elevated by 13-fold compared to healthy subjects (n=8, P<0.001). In a cross-sectional study of 139 cases, serum NGAL concentrations were determined independently by % creatinine generation rate (an indicator of muscle mass, standardized coefficient β=0.40, P<0.001), peripheral blood neutrophil count (β=0.38, P<0.001) and anion gap (which likely reflects dietary protein intake, β=0.16, P<0.05). Iron administration to anemic HD patients caused marked elevation of peripheral blood hemoglobin, serum ferritin and iron-regulatory hormone hepcidin-25 levels, but NGAL levels were not affected. In a prospective study of 87 cases, increase in serum albumin levels a year later was positively associated to baseline NGAL levels by univariate analysis (r=0.36, P<0.01). Furthermore, within a year, patients with the lowest NGAL tertile showed significantly increased risk for marked decline in serum albumin levels (≥0.4 g/dl; odds ratio 5.5, 95% confidence interval 1.5–20.3, P<0.05) and tendency of increased occurrence of severe infection requiring admission (odds ratio 3.1, not significant) compared to the middle and highest tertiles.

Conclusion

Low serum NGAL levels appear to be associated with current malnutrition and also its progressive worsening in maintenance HD patients.

Detection and evaluation of renal biomarkers in a swine model of acute myocardial infarction and reperfusion

The prevalence of type 1 cardiorenal syndrome (CRS) is increasing and strongly associated with long-term mortality. However, lack of reliable animal models and well-defined measures of renoprotection, made early diagnosis and therapy difficult. We previously successfully established the swine acute myocardial infarction (AMI) model of ischemia-reperfusion by blocking left anterior descending branch (LAD). Reperfusion was performed after 90-minute occlusion of the LAD. AMI was confirmed by ECG and left ventricular angiography (LVG). Then those 52 survived AMI reperfusion swine, including ventricular fibrillation-cardiac arrest after restoration of blood flow, were randomly divided into four groups (four/group) according to different interventions: resuscitation in room temperature, resuscitation with 500 ml saline in room temperature, resuscitation with 4°C 500 ml saline and normal control (with no intervention of resuscitation). Each group was further observed in four groups according to different time of resuscitation after ventricular arrhythmias: 1, 3, 5, 10-minute reperfusion after ventricular arrhythmias. Plasma and random urine were collected to evaluate renal function and test renal biomarkers of acute kidney injury (AKI). Our swine AMI model of ischemia-reperfusion provoked subclinical AKI with the elevation of the tubular damage biomarker, NGAL, IL-18 and L-FABP. Renal damage rapidly observed after hemodynamic instability, rather than observation after several hours as previously reported. The increasing rate of biological markers declined after interventions, however, its impact on the long-term prognosis remains to be further studied. These data show that elevation of tubular damage biomarkers without glomerular function loss may indicate appropriate timing for effective renoprotections like hypothermia resuscitation in type 1 CRS.

Reference ranges for serum β-trace protein in neonates and children younger than 1 year of age

BACKGROUND

β-Trace protein (BTP) has been proposed as an alternative endogenous marker of glomerular filtration rate. Data on BTP reference ranges in young children are scarce. We therefore aim to establish reference ranges and examine the developmental course of serum BTP in basically healthy children younger than 1 year of age.

METHODS

Single blood samples were taken from healthy children (born at gestational age ≥37 weeks) <12 months of age. Serum BTP was measured using the N latex B-trace protein assay (Siemens Diagnostics, Deerfield, IL, USA) on an Immage® 800 Rate Nephelometer (Beckman Coulter Inc. Brea, CA, USA). Serum creatinine and cystatin C were additionally determined and compared to reference values to confirm a normal renal function.

RESULTS

From June 2010 to January 2014, 95 blood samples were collected from 95 children {67.4% male; median age 120 days [inter quartile range 57-166]}. BTP was normally distributed (mean concentration 0.84±standard deviation 0.35 mg/L). Considering all children, the 50th centile BTP reference concentration was 0.82 mg/L (5th-95th centiles; 0.27-1.38). BTP concentrations were the highest in neonates and steadily declined with increasing age (Spearman's rank correlation was -0.415, p=0.002). No gender differences were found.

CONCLUSIONS

Our data provide a BTP reference range for the first year of life. Seeing the biological pattern of BTP, with only a limited postnatal decline, this marker might offer a promising alternative to serum creatinine-based methods for estimating glomerular filtration rate in newborns.

Over-expression of lipocalin 2 promotes cell migration and invasion through activating ERK signaling to increase SLUG expression in prostate cancer

BACKGROUND

Metastasis is the primary cause of prostate cancer (PCa) lethality and poses a huge clinical obstacle. Lipocalin 2 (LCN2), a member of the lipocalin family, is aberrantly expressed in some human cancers and has been implicated in the progression of some tumors. However, the role of LCN2 in the metastatic capacity of prostate cancer (PCa) is poorly understood.

METHODS

LCN2 expression was examined by RT-qPCR and/or immunoblotting in human prostate tissue specimens and prostate cancer cell lines LNCaP, C4-2, 22RV1, PC3, DU-145, and PC3MM2. LCN2 protein level in human serum samples was determined by ELISA. Lentiviruses-mediated over-expression of LCN2 and knockdown of LCN2 was conducted to evaluate the role of LCN2 in cell migratory and invasive capacities of prostate cancer cells. Cell migration and invasion was examined by transwell chamber assay. Knockdown of SLUG by lentivirus was performed to investigate its role in LCN2-promoted cell migration and invasion in vitro (22RV1 cell line) and metastasis in vivo (tail vein metastasis assay in nude mice). Role of ERK signaling in LCN2-mediated up-regulation of SLUG was assayed by using ERK inhibitor U0126.

RESULTS

We confirmed that LCN2 levels were correlated positively with invasive prostate cancer in human tissue and serum samples, and were also consistently associated with the invasive capacity of prostate cancer cell lines. The over-expression of LCN2 in 22RV1 cells (not highly invasive) promoted the epithelial-mesenchymal transition (EMT), increasing cell motility and invasiveness, while the knockdown of LCN2 in PC3 cells (highly invasive) inhibited EMT, decreasing cell motility and invasiveness. Among the multiple EMT transcription factors, LCN2 specifically induces the expression of SLUG, which was shown here to be required for the LCN2-induced increase in the invasive capacity of prostate cancer cells both in vitro and in vivo. Mechanistically, LCN2 promoted SLUG expression via activating ERK signaling pathway.

CONCLUSION

LCN2 plays an important role in promoting cell migration and invasion of prostate cancer by inducing EMT through the ERK/SLUG axis. Therefore, targeted inhibition of LCN2 may represent a therapeutic strategy to prevent the metastasis of prostate cancer.

Association of Perioperative Plasma Neutrophil Gelatinase-Associated Lipocalin Levels with 3-Year Mortality after Cardiac Surgery: A Prospective Observational Cohort Study

Background

Higher levels of plasma neutrophil gelatinase-associated lipocalin (pNGAL) are an early marker of acute kidney injury and are associated with increased risk of short-term adverse outcomes. The independent association between pNGAL and long-term mortality is unknown.

Methods

In this prospective observational cohort study, we studied 1191 adults who underwent cardiac surgery between 2007 and 2009 at 6 centers in the TRIBE-AKI cohort. We measured the pNGAL on the pre-operative and first 3 post-operative days and assessed the relationship of peri-operative pNGAL concentrations with all-cause mortality.

Results

During a median follow-up of 3.0 years, 139 participants died (50/1000 person-years). Pre-operative levels of pNGAL were associated with 3-year mortality (unadjusted HR 1.96, 95% CI 1.34,2.85) and the association persisted after adjustment for pre-operative variables including estimated glomerular filtration rate (adjusted HR 1.48, 95% CI 1.04–2.12). After adjustment for pre- and intra-operative variables, including pre-operative NGAL levels, the highest tertiles of first post-operative and peak post-operative pNGAL were also independently associated with 3-year mortality risk (adjusted HR 1.31, 95% CI 1.0–1.7 and adjusted HR 1.78, 95% CI 1.2–2.7, respectively). However, after adjustment for peri-operative changes in serum creatinine, there was no longer an independent association between the first post-operative and peak post-operative pNGAL and long-term mortality (adjusted HR 0.98,95% CI 0.79–1.2 for first pNGAL and adjusted HR 1.19, 95% CI 0.87–1.61 for peak pNGAL).

Conclusions

Pre-operative pNGAL levels were independently associated with 3-year mortality after cardiac surgery. While post-operative pNGAL levels were also associated with 3-year mortality, this relationship was not independent of changes in serum creatinine. These findings suggest that while pre-operative pNGAL adds prognostic value for mortality beyond routinely available serum creatinine, post-operative pNGAL measurements may not be as useful for this purpose.

Opinion paper on utility of point-of-care biomarkers in the emergency department pathways decision making

Overcrowding of the emergency department (ED) is rapidly becoming a global challenge and a major source of concern for emergency physicians. The evaluation of cardiac biomarkers is critical for confirming diagnoses and expediting treatment decisions to reduce overcrowding, however, physicians currently face the dilemma of choosing between slow and accurate central-based laboratory tests, or faster but imprecise assays. With improvements in technology, point-of-care testing (POCT) systems facilitate the efficient and high-throughput evaluation of biomarkers, such as troponin (cTn), brain natriuretic peptide (BNP) and neutrophil gelatinase-associated lipocalin (NGAL). In this context, POCT may help ED physicians to confirm a diagnosis of conditions, such as acute coronary syndrome, heart failure or kidney damage. Compared with classic laboratory methods, the use of cTn, BNP, and NGAL POCT has shown comparable sensitivity, specificity and failure rate, but with the potential to provide prompt and accurate diagnosis, shorten hospital stay, and alleviate the burden on the ED. Despite this potential, the full advantages of rapid delivery results will only be reached if POCT is implemented within hospital standardized procedures and ED staff receive appropriate training.

The multi-biomarker approach for heart failure in patients with hypertension

We assessed the predictive ability of selected biomarkers using N-terminal pro-brain natriuretic peptide (NT-proBNP) as the benchmark and tried to establish a multi-biomarker approach to heart failure (HF) in hypertensive patients. In 120 hypertensive patients with or without overt heart failure, the incremental predictive value of the following biomarkers was investigated: Collagen III N-terminal propeptide (PIIINP), cystatin C (CysC), lipocalin-2/NGAL, syndecan-4, tumor necrosis factor-α (TNF-α), interleukin 1 receptor type I (IL1R1), galectin-3, cardiotrophin-1 (CT-1), transforming growth factor β (TGF-β) and N-terminal pro-brain natriuretic peptide (NT-proBNP). The highest discriminative value for HF was observed for NT-proBNP (area under the receiver operating characteristic curve (AUC) = 0.873) and TGF-β (AUC = 0.878). On the basis of ROC curve analysis we found that CT-1 > 152 pg/mL, TGF-β < 7.7 ng/mL, syndecan > 2.3 ng/mL, NT-proBNP > 332.5 pg/mL, CysC > 1 mg/L and NGAL > 39.9 ng/mL were significant predictors of overt HF. There was only a small improvement in predictive ability of the multi-biomarker panel including the four biomarkers with the best performance in the detection of HF—NT-proBNP, TGF-β, CT-1, CysC—compared to the panel with NT-proBNP, TGF-β and CT-1 only. Biomarkers with different pathophysiological backgrounds (NT-proBNP, TGF-β, CT-1, CysC) give additive prognostic value for incident HF in hypertensive patients compared to NT-proBNP alone.

Plasma neutrophil gelatinase-associated lipocalin as a potential predictor of adverse renal outcomes in immunoglobulin A nephropathy

BACKGROUND/AIMS

Neutrophil gelatinase-associated lipocalin (NGAL) is a well-known biomarker of acute kidney injury. We evaluated the value of plasma NGAL (pNGAL) as an independent predictor of prognosis in immunoglobulin A nephropathy (IgAN).

METHODS

In total, 91 patients with biopsy-proven IgAN at a single center were evaluated. pNGAL was measured using a commercial enzyme-linked immunosorbent assay kit (R&D Systems). Adverse renal outcome was defined as chronic kidney disease (CKD) stage 3 or above at the last follow-up. Pearson correlation coefficient and Cox regression were used for analyses.

RESULTS

The mean age of all patients (male:female, 48:43) was 35 years (range, 18 to 77). pNGAL ranged between 21.68 and 446.40 ng/mL (median, 123.97) and showed a correlation with age (r = 0.332, p = 0.001), creatinine (r = 0.336, p = 0.001), estimated glomerular filtration rate (r = -0.397, p < 0.001), uric acid (r = 0.289, p = 0.006), and the protein-to-creatinine ratio (r = 0.288, p = 0.006). During a mean follow-up period of 37.6 months, 11 patients (12.1%) had CKD stage 3 or above. In a multivariate Cox regression model, hypertension (hazard ratio [HR], 8.779; 95% confidence interval [CI], 1.526 to 50.496; p = 0.015), proteinuria > 1 g/day (HR, 5.184; 95% CI, 1.124 to 23.921; p = 0.035), and pNGAL (HR, 1.012; 95% CI, 1.003 to 1.022; p = 0.013) were independent predictors associated with adverse renal outcome.

CONCLUSIONS

pNGAL showed strong correlations with other clinical prognostic factors and was also an independent predictor of adverse renal outcome. We suggest pNGAL as a potential predictor for prognosis in IgAN, while further studies are needed to confirm the clinical value.

High serum and urine neutrophil gelatinase-associated lipocalin levels are independent predictors of renal progression in patients with immunoglobulin A nephropathy

BACKGROUND/AIMS

Tubulointerstitial injury plays an important role in the progression of immunoglobulin A nephropathy (IgAN), and neutrophil gelatinase-associated lipocalin (NGAL) is among the most sensitive tubular biomarkers. We investigated whether serum or urine NGAL predicts prognosis in patients with IgAN.

METHODS

The present study enrolled patients with biopsy-proven IgAN from January 2005 to December 2010, whose serum and urine samples at the time of kidney biopsy were preserved by freezing. We retrospectively reviewed patient clinical data and followed patients until October 2012. Serum and urine NGAL levels were measured using an enzyme-linked immunosorbent assay kit. Renal progression was defined as an estimated glomerular filtration rate decline by > 50% or progression to end-stage renal disease.

RESULTS

There were 121 patients enrolled in this study. During the median follow-up period of 41.49 months, renal progression was found in nine patients (7.4%). Serum or urine NGAL alone could not predict renal progression; however, when serum and urine NGAL levels were combined, belonging to the high NGAL group independently predicted renal progression (hazard ratio [HR], 5.56; 95% confidence interval [CI], 1.42 to 21.73; p = 0.014), along with tubular damage graded according to the Oxford classification as T2 (HR, 8.79; 95% CI, 2.01 to 38.51; p = 0.004). In addition, a Kaplan-Meier curve of renal survival showed significantly higher renal progression in patients in the high NGAL group (log rank, p = 0.004).

CONCLUSIONS

In patients with IgAN, high serum and urine NGAL levels at the time of kidney biopsy predict renal progression.

Ameliorative effect of chrysin on adenine-induced chronic kidney disease in rats

Chrysin (5, 7- dihydroxyflavone) is a flavonoid with several pharmacological properties that include antioxidant, anti-inflammatory and antiapoptotic activities. in this work, we investigated some effects of three graded oral doses of chrysin (10, 50 and 250 mg/kg) on kidney structure and function in rats with experimental chronic renal disease (CKD) induced by adenine (0.25% w/w in feed for 35 days), which is known to involve inflammation and oxidative stress. Using several indices in plasma, urine and kidney homogenates, adenine was found to impair kidney function as it lowered creatinine clearance and increased plasma concentrations of creatinine, urea, neutrophil gelatinase-associated lipocalin and N-Acetyl-beta-D-glucosaminidase activity. Furthermore, it raised plasma concentrations of the uremic toxin indoxyl sulfate, some inflammatory cytokines and urinary albumin concentration. Renal morphology was severely damaged and histopathological markers of inflammation and fibrosis were especially increased. In renal homogenates, antioxidant indices, including superoxide dismutase and catalase activities, total antioxidant capacity and reduced glutathione were all adversely affected. Most of these adenine – induced actions were moderately and dose -dependently mitigated by chrysin, especially at the highest dose. Chrysin did not cause any overt adverse effect on the treated rats. The results suggest that different doses of chrysin produce variable salutary effects against adenine-induced CKD in rats, and that, pending further pharmacological and toxicological studies, its usability as a possible ameliorative agent in human CKD should be considered.

Plasma Neutrophil Gelatinase-Associated Lipocalin Is Primarily Related to Inflammation during Sepsis: A Translational Approach

Acute kidney injury (AKI) during sepsis is common and underestimated. Plasma neutrophil gelatinase-associated lipocalin (plasma-NGAL) is discussed as new biomarker for AKI diagnosis, but during inflammation its function and diagnostic impact remain unclear. The association between plasma-NGAL and inflammatory markers in septic patients, but also in healthy controls and patients with chronic inflammation before and after either maximum exercise test or treatment with an anti-TNF therapy were investigated. In-vitro blood stimulations with IL-6, lipopolysaccharide, NGAL or its combinations were performed to investigate cause-effect-relationship. Plasma-NGAL levels were stronger associated with inflammation markers including IL-6 (Sepsis: r=0.785 P<0.001; chronic inflammation after anti-TNF: r=0.558 P<0.001), IL-8 (Sepsis: r=0.714 P<0.004; healthy controls after exercise r=0.786 P<0.028; chronic inflammation before anti-TNF: r=0.429 P<0.041) and IL-10 (healthy controls before exercise: r=0.791 P<0.028) than with kidney injury or function. Correlation to kidney injury or function was found only in septic patients (for creatinine: r= 0.906 P<0.001; for eGFR: r= -0.686 P=0.005) and in patients with rheumatic disease after anti-TNF therapy (for creatinine: r= 0.466 P<0.025). In stimulation assays with IL-6 and lipopolysaccharide plasma-NGAL was increased. Co-stimulation of lipopolysaccharide with plasma-NGAL decreased cellular injury (P<0.05) and in trend IL-10 levels (P=0.057). Septic mice demonstrated a significantly improved survival rate after NGAL treatment (P<0.01). Plasma-NGAL seams to be strongly involved in inflammation. For clinical relevance, it might not only be useful for AKI detection during severe inflammation - indeed it has to be interpreted carefully within this setting - but additionally might offer therapeutic potential.

Combined biomarker analysis for risk of acute kidney injury in patients with ST-segment elevation myocardial infarction

BACKGROUND

Acute kidney injury (AKI) complicating ST-segment elevation myocardial infarction (STEMI) increases subsequent morbidity and mortality. We combined the biomarkers of heart failure (HF; B-type natriuretic peptide [BNP] and soluble ST2 [sST2]) and renal injury (NGAL [neutrophil gelatinase-associated lipocalin] and cystatin C) in predicting the development of AKI in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

From March 2010 to September 2013, 189 STEMI patients were sequentially enrolled and serum samples were collected at presentation for BNP, sST2, NGAL and cystatin C analysis. 37 patients (19.6%) developed AKI of varying severity within 48 hours of presentation. Univariate analysis showed age, Killip class ≥2, hypertension, white blood cell counts, hemoglobin, estimated glomerular filtration rate, blood urea nitrogen, creatinine, and all the four biomarkers were predictive of AKI. Serum levels of the biomarkers were correlated with risk of AKI and the Acute Kidney Injury Network (AKIN) stage and all significantly discriminated AKI (area under the receiver operating characteristic [ROC] curve: BNP: 0.86, sST2: 0.74, NGAL: 0.75, cystatin C: 0.73; all P < 0.05). Elevation of ≥2 of the biomarkers higher than the cutoff values derived from the ROC analysis improved AKI risk stratification, regardless of the creatine level (creatinine < 1.24 mg/dL: odds ratio [OR] 11.25, 95% confidence interval [CI] 1.63-77.92, P = 0.014; creatinine ≥ 1.24: OR 15.0, 95% CI 1.23-183.6, P = 0.034).

CONCLUSIONS

In this study of STEMI patients undergoing primary PCI, the biomarkers of heart failure (BNP and sST2) and renal injury (NGAL and cystatin C) at presentation were predictive of AKI. High serum levels of the biomarkers were associated with an elevated risk and more advanced stage of AKI. Regardless of the creatinine level, elevation of ≥2 of the biomarkers higher than the cutoff values indicated a further rise in AKI risk. Combined biomarker approach may assist in risk stratification of AKI in patients with STEMI.

NGAL and cystatin C: two possible early markers of diabetic nephropathy in young patients with type 1 diabetes mellitus: one year follow up

OBJECTIVE

Diabetic nephropathy constitutes a major long-term complication in patients with type 1 diabetes mellitus (T1D) and its diagnosis is based on microalbuminuria. The aim of this observational follow-up study was to explore the role of neutrophil-gelatinase-associated lipocalin (NGAL) and cystatin C in unravelling early diabetic nephropathy even in patients with normoalbuminuria.

DESIGN

Fifty-six euthyroid patients with T1D, with mean age 13.1 (SD: 3.2) years, and 49 healthy controls with mean age 12.8 (SD: 6.6) were recruited. Besides standard blood chemistry and urinary albumin excretion, serum NGAL (ELISA) and cystatin C (nephelometry) were measured at enrollment and after 12-15 months. GFR was calculated with the bedside Schwartz formula (eGFR) and the Lund strategy formula (L-eGFR).

RESULTS

At baseline, mean NGAL levels were not significantly different between children with diabetes and controls. At re-evaluation, mean NGAL value and mean eGFR value in patients with diabetes were increased (p=0.032 and p=0.003 respectively). At both baseline and reevaluation, NGAL was positively correlated with cystatin C (r=0.41, p<0.001), systolic arterial pressure z-score (r=0.3, p=0.031) and creatinine (r=0.32, p=0.010). NGAL correlated negatively with eGFR (r=-0.26, p=0.049) and L-eGFR (r=-0.33, p=0.010). Cystatin C had a negative correlation to eGFR (r=-0.29, p=0.025) and a positive one with creatinine (r=0.35, p=0.009) at reevaluation. No statistically significant correlation was found between cystatin C and microalbuminuria (p=0.736).

CONCLUSIONS

NGAL and cystatin C, known markers of renal injury, correlate with renal function decline in T1D, suggesting that they may be used as supplementary tests to urine albumin excretion in order to unmask early renal dysfunction.

Effects of storage conditions on the stability of serum CD163, NGAL, HMGB1 and MIP2

BACKGROUND

Several cytokines have been involved in the diagnosis and prognosis for the pathogenesis and severity of chronic hepatitis B (CHB) such as cluster of differentiation 163 (CD163), neutrophil gelatinase-associated lipocalin (NGAL), high-mobility group box 1 (HMGB1) and macrophage inflammatory protein-2 (MIP-2). Nevertheless, the stability and reliability of these cytokines can be greatly influenced by handling and storage processes.

METHODS

In this study, potential utility of serum samples of a CHB cohort was evaluated to investigate several processes that might impact cytokine profiles such as temperature, storage time and number of freeze-thaw cycles. Blood samples collected from 100 patients with CHB were separated immediately and divided into two groups. In one group, samples (n=50) stored at -80 °C were subject to 1-3 freeze-thaw cycles. In the other group, samples (n=50) were stored at 4 °C and 25 °C for 3 h, 9 h, 24 h, 48 h, 72 h, and 7 d time points, respectively. To assess the influence of different storage conditions on cytokines, the levels of CD163, NGAL, HMGB1 and MIP-2 were measured using enzyme-linked immunosorbent assays (ELISA) kits.

RESULTS

No significant differences of these four cytokines after 1-3 repeated freeze-thaw cycles. Significant differences of NAGL levels were seen between 9 h and 7 d (P<0.05), and also in HMGB1 at 25 °C, while the other cytokines were relatively stable at the two storage temperatures over the various time points.

CONCLUSION

This study indicated that these four cytokines remained stable within three freeze-thaw cycles and 7 d at 4 °C. No perceptible effects on CD163 and MIP-2 levels were presented under the storage condition of 7 d at room temperature, whereas the degradation of NGAL and HMGB1 were notable.

Nephrotoxic effects of varenicline as the most effective drug used for smoking cessation: a preliminary experimental study

PURPOSE

Varenicline is a new most effective drug for smoking cessation. Its effect on kidney functions remains unclear. This study purposed to investigate whether varenicline causes nephrotoxicity in rats.

METHODS

Fifteen rats were randomly assigned to three groups: control, 0.0125 mg kg(-1) varenicline and 0.025 mg kg(-1) varenicline (single dose for 3 days, i.p.). Before and after experimental period, serum neutrophil gelatinase-associated lipocalin, creatinine and urea levels were measured. Total oxidant and antioxidant status were measured in kidney homogenates. Histological examination was performed in kidney.

RESULTS

The nephrotoxic effects of varenicline were detected by histopathological and biochemical examinations in the varenicline treatment groups. No change was observed in the control group.

CONCLUSIONS

These findings firstly indicate that a 3-day varenicline treatment causes nephrotoxic effects in rats.

Plasma neutrophil gelatinase-associated lipocalin and kidney function decline and kidney disease-related clinical events in older women

BACKGROUND

It is still unclear whether serum neutrophil gelatinase-associated lipocalin (NGAL), a biomarker of renal tubular injury, is a prognostic marker for the progression of chronic kidney disease (CKD) in the general population.

METHODS

A prospective-cohort study of 1,245 women aged ≥70 from the general population. Associations between plasma NGAL and change in 5-year estimated glomerular filtration rate (eGFR), rapid renal decline and 10-year risk of acute or chronic renal disease-related hospitalisations and/or mortality were examined.

RESULTS

Compared to women with above-median plasma NGAL of 76.5 ng/l, women with below-median plasma NGAL had a 9.3% reduction in eGFR over a 5-year period. Among women with above-median plasma NGAL, there was over a 1.7-fold increased risk of rapid renal decline (eGFR decline of >3 ml/min/year) (adjusted odds ratio 1.76, 95% CI 1.003, 3.102, p = 0.049). Compared to women with baseline eGFR of <60 ml/min/1.73 m(2), women with above-median plasma NGAL experienced over a 2.5-fold increased risk of renal disease events at 10 years (hazard ratio 2.55, 95% CI 1.13, 5.78, p = 0.025) after adjustment of age, hypertension and diabetes. Addition of plasma NGAL in participants with eGFR of <60 ml/min/1.73 m(2) significantly improved the accuracy in predicting the 10-year risk of renal disease events (adjusted area-under-curve receiver operator characteristics without and with NGAL 0.64 and 0.71, respectively; p = 0.027) and reclassified 13% of women who experienced renal disease events into the higher risk categories (p = 0.03).

CONCLUSION

Plasma NGAL is of modest clinical utility in predicting the renal function decline and risk of renal disease-related clinical events, particularly those with mild to moderate CKD.