Neutrophil Gelatinase-associated Lipocalin Concentrations Research Articles

Haemolysis and acute tubular injury after pulsed field ablation compared to radiofrequency: An observational study

Abstract Background Pulsed field ablation (PFA) represents a novel promising non-thermal alternative in non-pharmacological treatment of atrial fibrillation (AF). However, infrequent cases of acute renal failure secondary to intravascular haemolysis after a PFA procedure have been described. Objective To investigate the impact of ablation technology (PFA vs. radiofrequency ablation (RFA)) on the level of plasma cell-free haemoglobin (CFH) and the concentration of serum neutrophil gelatinase-associated lipocalin (NGAL) as a marker of tubular injury. Methods This was a prospective observational trial. In a consecutive cohort of patients who underwent AF ablation (PFA of RFA), blood samples were drawn just before the procedure (Sample 1: CFH and NGAL), immediately after the procedure (Sample 2: CFH) and one day after the procedure (Sample 3: CFH and NGAL). Plasma CHF level and serum NGAL concentration were analysed using the ELISA technique. Results Among 70 patients enrolled (mean age 64.3 ± 10.3 years, 61 % male), 23 underwent RFA and 47 PFA (22 pulmonary vein isolation (PVI) only and 25 PVI with other additive lesions). Baseline serum creatinine levels of both groups were comparable (91.7 ± 22.1 µmol/L vs. 88.8 ± 22.1 µmol/L P = 0.44). In the PFA cohort, a significant peak of CFH concentration was observed just after the procedure with a subsequent decrease within 12 hours (Sample 1 vs. Sample 2: 93.4 ± 65.1 µg/mL vs. 2394.9 ± 1966.1 µg/mL P < 0.001, Sample 1 vs. Sample 3: 93.4 ± 65.1 µg/mL vs. 97.2 ± 68.5 µg/mL P = 0.75). No significant differences were observed in the RFA cohort. Compared to baseline, neither the PFA nor the RFA group showed a significant difference in NGAL levels (PFA 98.6 ± 31.7 ng/mL vs. 98.5 ± 38.1 ng/mL P = 0.78, RFA 108.3 ± 33.8 ng/mL vs. 116.3 ± 32.2 ng/mL P = 0.49). Conclusions Compared to RFA, PFA leads to significant peri-procedural haemolysis. However, no differences in the concentration of the tubular injury marker NGAL were observed on the first day after the procedure.

Assessment of Neutrophil Gelatinase Associated Lipocalin in Children with Acute Gastroenteritis and Dehydration to Identify Early Signs of Acute Kidney Injury

Background: Gastroenteritis often correlates with acute kidney injury (AKI) in children who are hospitalized. The primary diagnostic test for acute kidney injury (AKI) in modern times is serum creatinine (SCr), which increases in the presence of AKI and is eliminated by glomerular filtration. SCr is an unsuitable biomarker for renal sickness because it lacks specificity and a slow response to disease severity or treatment changes. NGAL, or neutrophil gelatinase-associated lipocalin, is a molecular weight of 25 kDa protein and forms a covalent bond with neutrophil gelatinase. Elevations in NGAL levels due to kidney injury have important predictive value and may forecast the onset of acute kidney injury (AKI) 24-72 hours before an increase in diagnostic serum creatinine (SCr) values. Aim and objectives: This study aims to determine whether plasma NGAL concentrations in mild, moderate, or severe dehydrated acute gastroenteritis patients may indicate acute kidney damage (AKI). The research will investigate whether acute renal injury and plasma NGAL concentrations are connected. Patients and methods: The cross-sectional design was employed in this study and included 80 patients who attended the pediatric gastrointestinal clinic at Babylon Children's Hospital. Between November 2022 and June 2023, all patients had gastroenteritis symptoms accompanied by different dehydration levels. Results: Patients with severe dehydration had considerable higher level of NGAL than those with mild to moderate dehydration (p<0.001). There was a notable inverse relationship (p = 0.046) between the NGAL level and potassium but a considerable direct link (p<0.001) between the NGAL level and creatinine. However, no significant correlation was seen between the NGAL level and urea (p = 0.404 and 0.062, respectively). The confidence range for the area under the curve (AUC) is 0.940 to 0.981, with a confidence level of 95%. The p-value is less than 0.001. The sensitivity is 88%. An accuracy of 88.4% has been attained. The NGAL cut-off point is 3.9832. Conclusion: An analysis of plasma neutrophil gelatinase-associated lipocalin (NGAL) in individuals with gastroenteritis and varied degrees of dehydration indicated a clear and direct link between the two parameters. Specifically, when dehydration worsened, the average NGAL value increased

Impacts of age, type 2 diabetes, and hypertension on circulating neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 after prolonged work in the heat in men.

Prolonged work in the heat increases the risk of acute kidney injury (AKI) in young men. Whether aging and age-associated chronic disease may exacerbate the risk of AKI remains unclear. We evaluated plasma neutrophil gelatinase-associated lipocalin (NGAL) and serum kidney injury molecule-1 (KIM1) before and after 180min of moderate-intensity work (200W/m2) in temperate (wet-bulb globe temperature [WBGT] 16°C) and hot (32°C) environments in healthy young (n = 13, 22years) and older men (n = 12, 59years), and older men with type 2 diabetes (T2D; n = 9, 60years) or hypertension (HTN; n = 9, 60years). There were no changes in NGAL or KIM1 concentrations following prolonged work in temperate conditions in any group. Despite a similar work tolerance, the relative change in NGAL was greater in the older group when compared to the young group following exercise in the hot condition (mean difference + 82ng/mL; p < 0.001). Baseline concentrations of KIM1 were ~ 22pg/mL higher in the older relative to young group, increasing by ~ 10pg/mL in each group after exercise in the heat (both p ≤ 0.03). Despite a reduced work tolerance in the heat in older men with T2D (120 ± 40min) and HTN (108 ± 42min), elevations in NGAL and KIM1 were similar to their healthy counterparts. Age may be associated with greater renal stress following prolonged work in the heat. The similar biomarker responses in T2D and HTN compared to healthy older men, alongside reduced exercise tolerance in the heat, suggest these individuals may exhibit greater vulnerability to heat-induced AKI if work is prolonged.

Polycystic Ovary Syndrome Accompanied by Hyperandrogenemia or Metabolic Syndrome Triggers Glomerular Podocyte Injury.

Objective: To determine whether the urinary excretion of podocyte degradation products varies according to PCOS phenotype and metabolic syndrome (MetS). Methods: The concentrations of podocalyxin (PDX) and nephrin, chronic markers of podocyte damage, and neutrophil gelatinase-associated lipocalin (NGAL), a marker of acute glomerular damage, were analyzed in the morning urine samples of 50 PCOS patients and 50 healthy controls matched by age and BMI. Albuminuria was assessed by calculating the urine albumin-creatinine ratio (uACR). Results: The PDX, nephrin and NGAL concentrations of PCOS participants were significantly higher than those of the control group. While PDX, nephrin and NGAL levels of classic phenotypes were similar, they were higher than ovulatory and non-hyperandrogenic phenotypes. Significant increases in urinary levels of each podocyte protein were detected in PCOS patients with MetS compared to patients without MetS. A positive significant correlation between podocyte proteins and BMI, systolic blood pressure, testosterone, glucose, HOMA-IR and uACR. After adjusting for age and BMI, podocyte proteins were an independent risk factor for microalbuminuria. The incidence of microalbuminuria in PCOS increased 6-fold compared to controls. The frequency of microalbuminuria was higher in classical phenotypes than in ovulatory phenotype. The frequency of microalbuminuria in PCOS patients with MetS was 6.5 times higher than in PCOS patients without MetS. Conclusions: In PCOS accompanied by hyperandrogenemia or metabolic syndrome, leakage of acute and chronic podocyte breakdown products into the urine becomes more pronounced.

A silver auto-catalyzed plasmonic enzyme-linked immunosorbent assay for colorimetric and fluorescent detection of neutrophil gelatinase associated lipocalin (NGAL)

The conventional ELISA lacked sufficient sensitivity and accuracy for analyzing neutrophil gelatinase associated lipocalin (NGAL), a potential biomarker of ulcerative colitis. Here, we developed a dual-readout plasmonic ELISA with cascade amplification of alkaline phosphatase hydrolysis and O-phenylenediamine oxidation. In this novel plasmonic ELISA, alkaline phosphatase-conjugated antibodies capture NGAL from samples, alkaline phosphatase hydrolyzes 2-phospho-L-ascorbic acid into ascorbic acid, and then ascorbic acid blocks silver-catalyzed O-phenylenediamine oxidation by turning silver ions into silver microwires. Therefore, NGAL concentration is proportional to the decrease in chromogenic and fluorescent response. This novel plasmonic ELISA exhibited a linear range of 0.5–80 ng/mL, and the LOD was as low as 0.5 ng/mL. The sensitivity was superior to that of conventional ELISA and previous studies. The plasmonic ELISA exhibited favorable selectivity because of the specific antibody-antigen interaction and the robust cascade amplification. Besides, the dual-readout feature endowed the plasmonic ELISA with advantages in terms of convenience and compatibility. In summary, our study provided a novel and sensitive plasmonic ELISA for the diagnosis of ulcerative colitis.

Electrochemical Detection of Neutrophil Gelatinase-Associated Lipocalin (NGAL) in Simulated Urine Using Au@Si/Ni-Porphyrin Nanocomposite for the Prediction of Kidney Injury

Kidney Injury is multifactorial out of which ureteropelvic junction obstruction is one of the major causes of concern. There are a multitude of methods for monitoring the deterioration of renal function like serum creatinine levels, ultrasound scans, renograms, and nuclear scans like radiolabelled MAG3 and DMSA which require repeat evaluation or sedation during the process. Many of the biomarkers utilized for the assessment of kidney injury are expressed at the later stages. Urine NGAL is a promising biomarker for risk stratification which is reported to be expressed at the onset of ureteropelvic junction obstruction (UPJO) and is a gold standard for the estimation of tubular injury. Urinary NGAL is also reported to be a specific marker for the prediction of hydronephrosis in children who require surgical intervention. The kidney injury cut-off for NGAL in urine is 185ng/mL and 48 ng/mL in the adult and pediatric population groups respectively. Electrochemical detection of NGAL in patient urine is a fast, reliable, non-invasive, accurate, and cost-effective method for monitoring kidney health to segregate patient groups that require surgical intervention.In this study, an electrochemical sensor was designed with Au(150nm) electrodes fabricated using thermal evaporation on a flexible substrate (PET; 250μm) by using Cr(20nm) as the seed layer. The electrode was immobilized with Au@Si core-shell decorated on Ni-porphyrin nanosheets functionalized with anti-NGAL using covalent chemistry. The nanocomposite was synthesized through a bottom-up approach where the Ni-tetrakis(4-carboxyphenyl) porphyrin nanosheets were synthesized using the solvothermal method in an organic phase (DMF) followed by purification and suspension in ethanol medium. The Si nanocrystals were synthesized in a citrate medium with APTMS as the precursor followed by purification via dialysis. The purified Si nanocrystals (60ppm) and Ni-porphyrin nanosheets (880ppm) were treated in chloroauric acid (0.25mM) and the reducing agent trisodium citrate (34mM) to form Au shell. The physicochemical and electronic properties of the synthesized nanocomposite were evaluated through XRD, XPS, microscopic analysis(TEM, SEM), AFM, UV-Vis, FTIR, and Raman spectroscopy. The resultant nanocomposite was purified and linked to anti-NGAL (100μg/mL) through EDC (0.4M)/NHS (0.1M) chemistry. The antibody-nanocomposite was immobilized on the fabricated Au electrodes (working electrode surface area: 0.35mm2) through BSA(1.2mM)/glutaraldehyde (2.5% v/v) crosslinking. The quantitative electrochemical estimation of NGAL antigen spiked in 0.1M PBS (pH=7.2±0.2) and simulated urine was performed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The shelf life of the fabricated sensors was evaluated for 30 days (stored at 4˚ C until use) over the concentration range of 0-5000 ng/mL. The amount of test solution required per measurement for the miniaturized electrodes was 6μL.The sensing mechanism of the electrochemical platform was established through CV by varying the scan rate (0.05 V/s - 2.5 V/s) for 500ng/mL in 0.1M PBS and urine. With increasing scan rate a linear relationship between log ip and log ν was observed. For 0.1M PBS, the process was largely capacitive at various detected potentials (b=0.94 @ 0.5V; b=0.86 @ 0.3V; b=0.85 @ 0.07V). However, in the case of simulated urine, the electrochemical process was diffusion-limited at 0.6V (b=0.49). Therefore, to obtain higher current sensitivity in the diffusion-limited regime, DPV was adopted. With increasing concentration of antigen NGAL, a monotonic decrease in the redox current at 0.6V and 0.45V potential was observed. This signifies that the presence of NGAL antigen leads to the formation of antigen-antibody complex immobilized on the surface of the nanocomposite translating into an increase in the resistance at the electrode surface leading to a decrease in the redox current. The decrease in the current was proportional to the increase in the amount of the test antigen. The sensitivity of the sensor at 0.45V and 0.6V was 2.22 nA/ng mL-1/mm2 and 0.51 nA/ng mL-1/mm2 respectively with the lowest limit of NGAL detection as 12.5ng/mL in simulated urine by using DPV. Similarly, for CV the sensitivity of the sensor at 0.56V was 3.48 nA/ng mL-1/mm2 with 22ng/mL as the limit of detection. The sensor performance was evaluated without the use of nanocomposite (only antibody) as a control for comparison.Therefore, this study is a proof of concept for an effective electrochemical sensor platform design for urinary NGAL detection using a novel nanocomposite. It was established that the use of nanocomposite provides a better surface area to volume ratio through the core-shell nanostructures decorated on the nanosheets translating into higher electrochemical activity. The sensing platform was found to be specific, sensitive, and stable making it a perfect candidate for a point-of-care-testing(POCT) platform. Figure 1

Meconium Proteins Involved in Iron Metabolism.

The lack of specific biological materials and biomarkers limits our knowledge of the mechanisms underlying intrauterine regulation of iron supply to the fetus. Determining the meconium content of proteins commonly used in the laboratory to assess the transport, storage, and distribution of iron in the body may elucidate their roles in fetal development. Ferritin, transferrin, haptoglobin, ceruloplasmin, lactoferrin, myeloperoxidase (MPO), neutrophil gelatinase-associated lipocalin (NGAL), and calprotectin were determined by ELISA in meconium samples obtained from 122 neonates. There were strong correlations between the meconium concentrations of haptoglobin, transferrin, and NGAL (p < 0.05). Meconium concentrations of ferritin were several-fold higher than the concentrations of the other proteins, with the exception of calprotectin whose concentration was approximately three-fold higher than that of ferritin. Meconium ceruloplasmin concentration significantly correlated with the concentrations of MPO, NGAL, lactoferrin, and calprotectin. Correlations between the meconium concentrations of haptoglobin, transferrin, and NGAL may reflect their collaborative involvement in the storage and transport of iron in the intrauterine environment in line with their recognized biological properties. High meconium concentrations of ferritin may provide information about the demand for iron and its utilization by the fetus. The associations between ceruloplasmin and neutrophil proteins may indicate the involvement of ceruloplasmin in the regulation of neutrophil activity in the intrauterine environment.

Is the urinary neutrophil gelatinase-associated lipocalin concentration in children and adolescents with type 1 diabetes mellitus different from that in healthy children?

Diabetic kidney disease (DKD) is one of the major microvascular complications of type 1 diabetes mellitus (T1DM). Some studies suggest that changes of renal tubular components emerge before the glomerular lesions thus introducing the concept of diabetic tubulopathy with urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a potential marker of DKD. This concept was not confirmed in all studies. In 198 T1DM patients with median age 15 years and diabetes duration over one year, an albumin/creatinine ratio (ACR) was determined and uNGAL measured in spot urine sample. Urine samples for ACR and uNGAL were also collected in the control group of 100 healthy children of similar age. There was no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects (6.9 (2.8-20.1) ng/mL vs 7.9 (2.9-21.0) ng/mL, P = 0.969 and 6.8 (2.2-18.4) ng/mg vs 6.5 (1.9-13.4) ng/mg, P = 0.448, respectively) or between T1DM subjects with albuminuria A2 and albuminuria A1 (P = 0.573 and 0.595, respectively). Among T1DM patients 168 (85%) had normal uNGAL concentrations, while in 30 (15%) patients uNGAL was above the defined cut-off value of 30.9 ng/mL. There was no difference in BMI, HbA1c and diabetes duration between patients with elevated uNGAL compared to those with normal uNGAL. We found no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects or between albuminuria A2 and albuminuria A1 T1DM subjects. Therefore, uNGAL should not be recommended as a single marker for detecting diabetic kidney disease in children and adolescents.

Clinical Impacts of Urinary Neutrophil Gelatinase-Associated Lipocalin in Patients With Chronic Kidney Disease Undergoing Percutaneous Coronary Intervention.

Chronic kidney disease (CKD) is associated with poor prognosis in patients undergoing percutaneous coronary intervention (PCI). Urinary neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for renal injury. However, the association between urinary NGAL concentrations and renal and cardiovascular events in patients with CKD undergoing PCI has not been elucidated. This study investigated the clinical impact of urinary NGAL concentrations on renal and cardiovascular outcomes in patients with non-dialysis CKD undergoing PCI.Methods and Results: We enrolled 124 patients with non-dialysis CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) undergoing elective PCI. Patients were divided into low and high NGAL groups based on the median urinary NGAL concentration measured the day before PCI. Patients were monitored for renal and cardiovascular events during the 2-year follow-up period. Kaplan-Meier analyses showed that the incidence of renal and cardiovascular events was higher in the high than low NGAL group (log-rank P<0.001 and P=0.032, respectively). Multivariate Cox proportional hazards analyses revealed that urinary NGAL was an independent risk factor for renal (hazard ratio [HR] 4.790; 95% confidence interval [CI] 1.537-14.924; P=0.007) and cardiovascular (HR 2.938; 95% CI 1.034-8.347; P=0.043) events. Urinary NGAL could be a novel and informative biomarker for predicting subsequent renal and cardiovascular events in patients with CKD undergoing elective PCI.

#2307 Serum NGAL, MMP-9 and suPAR in the assessment of kidney impairment and cardiovascular risk in children and adolescents with type 1 diabetes or obesity

Abstract Background and Aims Type 1 diabetes mellitus (DM1) and obesity represent two chronic paediatric diseases with worryingly rising incidence, characterized by chronic inflammation, endothelial dysfunction and increased risk for kidney impairment and cardiovascular disease. The aim of this cross-sectional study was to explore the potential usefulness of serum Neutrophil Gelatinase-Associated Lipocalin (NGAL), Matrix Metalloproteinase-9 (MMP-9) and Soluble Urokinase Plasminogen Activator Receptor (suPAR) for predicting early kidney injury or increased cardiovascular risk in children and adolescents with DM1 or obesity. Method Serum samples were obtained from children and adolescents aged &amp;lt;18 years old with DM1 (n=35) or obesity (n=38) and normal renal function with no history of albuminuria, as well as from healthy controls (n=23). Serum NGAL, MMP-9 and suPAR concentrations were measured using commercially available sandwich ELISA kits (NGAL: (DY1757-05), MMP-9: (DMP900); suPAR: (DUP00); R&amp;D systems). All patients were evaluated for anthropometric indices (weight, height, BMI) while for different degrees of weight status we used the body mass index (BMI) z-score adjusted for age and sex. Estimated glomerular filtration rate (eGFR) was calculated according to the revised bedside Schwartz formula. Results Serum NGAL values were found significantly higher in patients with obesity but not in those with DM1. A positive correlation was found in patients with T1DM with diabetes duration (Spearman rho 0.364, p=0.044), and in all study participants with BMI z-score (Spearman rho 0.401, p=0.004). Furthermore, serum MMP-9 levels were significantly increased in patients with T1DM and in patients with obesity compared to controls. Mean serum suPAR levels were significantly higher in patients with obesity compared to patients with T1DM and controls, while children with T1DM had similar suPAR levels to controls (Table 1). Finally, serum suPAR levels showed a negative correlation with age (Spearman rho −0.359, p&amp;lt;0.001) and creatinine levels (Spearman rho −0.334, p=0.005), and a positive correlation with BMI z-score (Spearman rho 0.354, p=0.009). Conclusion Circulating NGAL, MMP-9 levels may prove useful as surrogate biomarkers to creatinine, GFR and albumin excretion rate for early detection of kidney injury, inflammation or endothelial dysfunction and cardiovascular complications in children and adolescents with T1DM or obesity. Children with obesity may have impaired inflammation status, kidney and endothelial function to a higher degree compared to children with T1DM, which may suggest that obesity may impose a greater health burden than T1DM, at least during childhood or the first years after T1DM diagnosis.

Admission plasma concentration of neutrophil gelatinase-associated lipocalin and -C-reactive protein have additive prognostic value in patients with STEMI

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): This work was supported by Righospitalets Forskningsfond (07IO) Lundbeck Foundation (R186-2015-2132). Background Inflammation plays an apparent critical role in patients with acute coronary syndrome (ACS) and is associated with mortality. However, the complex process is poorly understood. Neutrophil gelatinase-associated lipocalin (NGAL) is a novel biomarker originating from mature neutrophils and renal tubular cells. It has previously been shown to be associated with mortality and acute kidney injury in ACS patients. In this study we sought to assess the potential additive prognostic value of NGAL and its relation to other markers of inflammation. Methods In 1556 consecutive ST-elevation myocardial infarction (STEMI) patients, NGAL and C-reactive protein (CRP) plasma concentration were measured at hospital admission, before acute coronary angiography. Patients were stratified to plasma concentration of both biomarkers &amp;gt;/&amp;lt; the median concentration into 4 groups (low NGAL/ low CRP (group 1), low NGAL/high CRP (2), high NGAL/low CRP (3), high NGAL/high CRP(4)). Primary outcome was 30-day all-cause mortality. Results In total, 477 (31%), 324 (21%), 316 (20%), and 439 (28%) patients were stratified in group 1-4, respectively. With 0, 1, or 2 biomarker plasma concentration above the median (group 1 – 4), patients were older (61 – 67 years old, p&amp;lt;0.0001), had more comorbidity (hypertension (40 – 53%), p=0.002; previous stroke (4.0 – 9.9%), p=0.007; peripheral arterial disease (PAD) (2.6 – 10%), p&amp;lt;0.0001; chronic kidney dysfunction (CKD) (0.6 – 11%), p&amp;lt;0.0001) and more critical per-infarction circumstances (time from symptom debut to angiography (170 – 229 minutes), p&amp;lt;0.0001; cardiogenic shock (1.3 – 14%), p&amp;lt;0.0001, cardiac arrest (0.8 – 3.4%), p=0.0002) and lower left ventricular ejection fraction (LVEF) (48 – 43%, p&amp;lt;0.0001). Increased NGAL and CRP was associated with 30-day all-cause mortality (Figure A). Only high NGAL/high CRP was independently associated with 30-day mortality in a cox proportional hazard model when adjusting for age, hypertension, previous stroke, CKD, LVEF, and cardiogenic shock (HR (95% CI) 5.19 (1.20 – 22.52), p=0.03). Both CRP and NGAL had significant predictive value of 30-day mortality (AUC ROC 0.67, p&amp;lt;0.0001 and 0.78, p&amp;lt;0.0001, respectively). Combining NGAL and CRP did, however, not increase the predictive value of NGAL alone (AUC ROC 0.77, p=0.86) (Figure B). Conclusion Combined admission NGAL and CRP plasma concentration was independently associated with 30-day all-cause mortality in STEMI patients. Adding CRP to NGAL did, however, not increase the predictive value.Figure AFigure B

A Pilot Study of the Role of Selected Biomarkers of Kidney Injury in Dogs with Dilated Cardiomyopathy.

Heart and kidney diseases are among the most frequent medical conditions diagnosed in small animals. Due to the functional interconnection between these organs, the concept of the cardio-renal axis has been developed. In this context, renal disease or dysfunction often occurs secondary to heart diseases, such as dilated cardiomyopathy (DCM). DCM is the most common cardiomyopathy and a leading cause of mortality in large-breed dogs. Traditional biomarkers like creatinine or symmetric dimethylarginine concentration are not always effective, especially in the early stages of the disease, underscoring the need for more sensitive markers of renal impairment during heart failure (HF). This study aimed to evaluate the efficacy of selected biomarkers as indicators for early kidney damage in dogs with stage B2 DCM. We measured serum concentrations of cystatin C, KIM-1 (kidney injury molecule-1), and NGAL (neutrophil gelatinase-associated lipocalin) and their ratios to creatinine, analyzing their diagnostic values. Cystatin C was quantified using a sandwich enzyme immunoassay, while KIM-1 and NGAL were measured with enzyme-linked immunosorbent assay kits designed for canine diagnostics. The concentrations were indexed against serum creatinine. The study included 26 dogs: 9 with HF and 17 healthy controls. The mean ± standard deviation for healthy dogs for cystatin C, cystatin C/creatinine ratio, KIM-1, KIM-1/creatinine ratio, NGAL, and NGAL/creatinine ratio were 0.24 ± 0.04, 0.26 ± 0.07, 0.61 ± 0.07, 0.67 ± 0.13, 2.76 ± 1.8, and 2.79 ± 1.81, respectively. For DCM dogs, these values were 0.27 ± 0.1, 0.32 ± 0.12, 0.61 ± 0.08, 0.69 ± 0.17, 6.46 ± 5.22 (p = 0.02), and 7.99 ± 6.53 (p = 0.04). This study's findings suggest that during the asymptomatic phase of DCM, only NGAL concentration and the NGAL/creatinine ratio may serve as diagnostic markers for early-stage kidney injury.

Assessment of Urinary and Serum Neutrophil Gelatinase-Associated Lipocalin (NGAL) Levels as Novel Predictors for Vesicoureteral Reflux Diagnosis in Children with Febrile Urinary Tract Infection.

The invasive, expensive, and time-consuming nature of radiological examinations for vesicoureteral reflux (VUR) has compelled researchers to search for new markers to predict VUR. This study was designed to evaluate the usefulness of serum and urine concentrations of neutrophil gelatinase-associated lipocalin (NGAL) in predicting the existence of VUR. This cross-sectional study involved all patients with a first febrile urinary tract infection (UTI) referred to Ali Asghar Children's Hospital. Each patient included in the study had clinical symptoms of pyelonephritis and a positive urine culture. The patients were divided into 2 groups: VUR and non-VUR. The serum and urinary NGAL levels were calculated in both groups. The receiver operating characteristic (ROC) curve was used to look for serum and urinary NGAL cut-points that differentiated the VUR group from the non-VUR group. Among the 40 children in the study, 23 belonged to the VUR group. The median age was 2.5 years (range, 0.3-8 years), and 35 patients were girls. ROC curve analysis showed that only the urinary NGAL level was significantly related to VUR. There was no association between serum NGAL levels and VUR. According to the ROC curve, a urinary NGAL level cut-off value of 15 ng/mL was likely to be diagnostic of VUR with 82.6% sensitivity and 58.8% specificity. The urinary NGAL level, specifically with a cut-off value of 15 ng/mL, can indicate the existence of VUR in patients with UTI with near-acceptable levels of sensitivity and specificity.

Tissue-resident Lymphocytes Are Released During Hypothermic and Normothermic Machine Perfusion of Human Donor Kidneys.

Machine perfusion is the preferred preservation method for deceased donor kidneys. Perfusate fluid, which contains a complex mixture of components, offers potential insight into the organ's viability and function. This study explored immune cell release, particularly tissue-resident lymphocytes (TRLs), during donor kidney machine perfusion and its correlation with injury markers. Perfusate samples from hypothermic machine perfusion (HMP; n = 26) and normothermic machine perfusion (NMP; n = 16) of human donor kidneys were analyzed for TRLs using flow cytometry. Residency was defined by expressions of CD69, CD103, and CD49as. TRL release was quantified exclusively in NMP. Additionally, levels of cell-free DNA, neutrophil gelatinase-associated lipocalin, and soluble E-cadherin (sE-cadherin) were measured in NMP supernatants with quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Both HMP and NMP samples contained a heterogeneous population of TRLs, including CD4 + tissue-resident memory T cells, CD8 + tissue-resident memory T cells, tissue-resident natural killer cells, tissue-resident natural killer T cells, and helper-like innate lymphoid cells. Median TRL proportions among total CD45 + lymphocytes were 0.89% (NMP) and 0.84% (HMP). TRL quantities in NMP did not correlate with donor characteristics, perfusion parameters, posttransplant outcomes, or cell-free DNA and neutrophil gelatinase-associated lipocalin concentrations. However, CD103 + TRL release positively correlated with the release of sE-cadherin, the ligand for the CD103 integrin. Human donor kidneys release TRLs during both HMP and NMP. The release of CD103 + TRLs was associated with the loss of their ligand sE-cadherin but not with general transplant injury biomarkers.

Systemic reserve dysfunction and contrast-associated acute kidney injury following percutaneous coronary intervention.

Developing contrast-associated acute kidney injury (CA-AKI) following percutaneous coronary intervention (PCI) is closely related to patient-related risk factors as well as contrast administration. The diagnostic and prognostic roles of neutrophil gelatinase-associated lipocalin (NGAL) in CA-AKI following PCI are not well established. Consecutive patients undergoing PCI were enrolled prospectively. CA-AKI was defined as an increase in the serum creatinine level ≥0.3 mg/dL within 48 hours or ≥1.5 times the baseline within 7 days after PCI. Serum NGAL concentrations were determined immediately before and 6 hours after PCI. The participants were classified into four NGAL groups according to the pre- and post-PCI NGAL values at 75th percentile. CA-AKI occurred in 38 (6.4%) of 590 patients. With chronic kidney disease status (hazard ratio [HR] 1.63, 95% confidence interval [CI]: 1.06-2.52), NGAL groups defined by the combination of pre- and 6 h post-PCI values were independently associated with the occurrence of CA-AKI (HR 1.69, 95% CI: 1.16-2.45). All-cause mortality for 29-month follow-ups was different among NGAL groups (log-rank p<0.001). Pre-PCI NGAL levels significantly correlated with baseline cardiac, inflammatory, and renal markers. Although post-PCI NGAL levels increased in patients with larger contrast administration, contrast media made a relatively limited contribution to the development of CA-AKI. In patients undergoing PCI, the combination of pre- and post-PCI NGAL values may be a useful adjunct to current risk-stratification of CA-AKI and long-term mortality. CA-AKI is likely caused by systemic reserve deficiency rather than contrast administration itself.

Value of serum iron and urine neutrophil gelatinase-associated lipocalin in predicting the mortality of critically ill patients with sepsis.

We aimed to investigate the association of iron metabolism-related parameters with 60-day mortality in critically ill patients with sepsis. Serum or urine concentrations of iron metabolism-related parameters on intensive care unit admission were measured in a prospective cohort of 133 eligible patients with sepsis according to the Sepsis-3 criteria, and these values were compared between survivors and nonsurvivors, categorized according to their 60-day survival status. Cox regression analyses were performed to examine the association between iron parameters and 60-day mortality. Kaplan-Meier methods were used to illustrate the differences in survival between different iron parameters. Of the 133 patients included in the study, 61 (45.8%) had died by day 60. After adjusting for confounding variables, higher concentrations of serum iron (cut-off 9.5 μmol/mL) and higher concentrations of urine neutrophil gelatinase-associated lipocalin (uNGAL; cut-off 169.3 ng/mL) were associated with a significantly greater risk of death in the Cox regression analysis. These two biomarkers combined with Sequential Organ Failure Assessment (SOFA) scores increased the area under the receiver operating characteristic (AUROC) curve to 0.85. These findings suggest that higher concentrations of serum iron and uNGAL are each associated with higher 60-day mortality, and they add significant accuracy to this prediction in combination with SOFA. Abbreviations: uNGAL: urine neutrophil gelatinase-associated lipocalin; ICU: intensive care unit; SOFA: Sequential Organ Failure Assessment; APACHE II: the Acute Physiology and Chronic Health Evaluation II; ELISA: enzyme-linked immunosorbent assay; HR: hazard ratio; CIs: confidence intervals; WBC: white blood cell; TBIL: total bilirubin.

Clinical outcomes prediction in kidney transplantation by use of biomarkers from hypothermic machine perfusion.

The clinical outcomes of kidney transplantation from deceased donors have seen significant improvements with the use of machine perfusion (MP), now a standard practice in transplant centers. However, the use of perfusate biomarkers for assessing organ quality remains a subject of debate. Despite this, some centers incorporate them into their decision-making process for donor kidney acceptance. Recent studies have indicated that lactate dehydrogenase (LDH), glutathione S-transferase, interleukin-18, and neutrophil gelatinase-associated lipocalin (NGAL) could predict post-transplant outcomes. Between August 2016 and June 2017, 31 deceased-donor after brain death were included and stroke was the main cause of death. Pediatric patients, hypersensitized recipients were excluded. 43 kidneys were subjected to machine perfusion. Perfusate samples were collected just before the transplantation and stored at -80ºC. Kidney transplant recipients have an average age of 52 years, 34,9% female, with a BMI 24,6±3,7. We employed receiver operating characteristic analysis to investigate associations between these perfusate biomarkers and two key clinical outcomes: delayed graft function and primary non-function. The incidence of delayed graft function was 23.3% and primary non-function was 14%. A strong association was found between NGAL concentration and DGF (AUC=0.766, 95% CI, P=0.012), and between LDH concentration and PNF (AUC=0.84, 95% CI, P=0.027). Other perfusate biomarkers did not show significant correlations with these clinical outcomes. The concentrations of NGAL and LDH during machine perfusion could assist transplant physicians in improving the allocation of donated organs and making challenging decisions regarding organ discarding. Further, larger-scale studies are required.

Plasma Biomarkers Associated to Outcome in Patients with Sars-Cov-2 Infection

Background: A serious consequence of respiratory infections with SARS-CoV-2 is Acute Kidney Injury (AKI). The aim of this study was to evaluate some novel biomarkers measured in plasma for their associations with the outcome of this infection as to AKI and mortality. Methods: Four different HNL (Human Neutrophil Lipocalin) assays were constructed using different antibody configurations, reflecting both neutrophil and epithelial cell activities. TK-1 (Thymidine kinase-1) was measured as a sign of cell destruction and proliferation. For comparison the plasma concentrations of NGAL (Neutrophil Gelatinase Associated Lipocalin), the cytokines IL-6, IL-8 and IFN-γ and of cystatin C, and procalcitonin were also measured. One hundred and three patients with severe respiratory failure admitted to the ICU were sampled for blood at admittance and at day three (n=67) after admittance. Results: Sixty-five percent of the patients developed AKI. The performance of the HNL assay 763/8F was most closely associated to outcome as to AKI and mortality with Area Under the Receiver Operating Characteristics Curve (AUC) of 0.87 and a sensitivity of 80% and a specificity of 88% in COVID-19 patients with and without severe AKI (p&lt;0.0001). TK-1 was significantly related to the development of AKI (p=0.01) and the three cytokines were related to mortality (p=0.004-p&lt;0.001). Conclusion: The HNL variant 763/8F and TK-1 are novel biomarkers that might become useful and novel tools in the management of COVID-19 patients, but likely also in other patients affected by AKI.

Effects of high-intensity intermittent exercise versus moderate-intensity continuous exercise on renal hemodynamics assessed by ultrasound echo.

High-intensity intermittent exercise (HIIE) has become attractive for presenting a variety of exercise conditions. However, the effects of HIIE on renal function and hemodynamics remain unclear. This study aimed to compare the effects of HIIE and moderate-intensity continuous exercise (MICE) on renal hemodynamics, renal function, and kidney injury biomarkers. Ten adult males participated in this study. We allowed the participants to perform HIIE or MICE to consider the impact of exercise on renal hemodynamics under both conditions. Renal hemodynamic assessment and blood sampling were conducted before the exercise (pre) and immediately (post 0), 30 min (post 30), and 60 min (post 60) after the exercise. Urine sampling was conducted in the pre, post 0, and post 60 phases. There was no condition-by-time interaction (p = 0.614), condition (p = 0.422), or time effect (p = 0.114) regarding renal blood flow. Creatinine-corrected urinary neutrophil gelatinase-associated lipocalin concentrations increased at post 60 (p = 0.017), but none exceeded the cut-off values for defining kidney injury. Moreover, there were no significant changes in other kidney injury biomarkers at any point. These findings suggest that high-intensity exercise can be performed without decreased RBF or increased kidney injury risk when conducted intermittently for short periods.

The Utility of Noninvasive Urinary Biomarkers for the Evaluation of Vesicoureteral Reflux in Children.

Vesicoureteral reflux (VUR) is one of the most important disorders encountered in pediatric nephrology due to its frequency and potential evolution to chronic kidney disease (CKD). The aim of our study was to identify noninvasive and easy-to-determine urinary markers to facilitate the diagnosis and staging of VUR. We performed a cross-section study including 39 patients with VUR followed over three years (August 2021-September 2023) and 39 children without urinary disorder (the control group). We measured the urinary concentration of interleukin-6 (IL-6), cathelicidin (LL-37), and neutrophil gelatinase-associated lipocalin (NGAL) in VUR and healthy controls. Moreover, we analyzed the correlation between these biomarkers and the presence of renal scars (RS), reflux nephropathy (RN), and CKD. The NGAL concentrations were significantly higher in patients with VUR than in the controls (p = 0.02). Regarding the severity of the reflux, NGAL/creatinine and LL-37/creatinine were positively correlated with severe reflux (p = 0.04, respectively, p = 0.02). In patients with VUR and RS, LL-37/creatinine was significantly lower (p = 0.01). LL-37/creatinine with an AUC of 0.71 and NGAL/creatinine with an AUC of 0.72 could be acceptable diagnostic tests for severe VUR. In conclusion, urinary IL-6, NGAL, and LL-37 could serve as valuable markers for diagnosing and predicting outcomes in patients with VUR and RN.