Innate Bacteriostatic Mechanisms Defend the Urinary Tract.

Urinary tract infection (UTI) is the most common type of urogenital disease. UTI affects the urethra, bladder, ureter, and kidney. A total of 13.3% of women, 2.3% of men, and 3.4% of children in the United States will require treatment for UTI. Traditionally, bladder (cystitis) and kidney (pyelonephritis) infections are considered independently. However, both infections induce host defenses that are either shared or coordinated across the urinary tract. Here, we review the chemical and biophysical mechanisms of bacteriostasis, which limit the duration and severity of the illness. Urinary bacteria attempt to overcome each of these defenses, complicating description of the natural history of UTI.

A prospective, multicenter, three-cohort study evaluating contrast-induced acute kidney injury (CI-AKI) in patients with cirrhosis.

BACKGROUND & AIMS: Nephrotoxicity of intravenous iodinated contrast media (ICM) in cirrhosis is still a debated issue, due to scarce, low-quality and conflicting evidence. This study aims to evaluate the incidence and predisposing factors of acute kidney injury (AKI) in patients with cirrhosis undergoing contrast-enhanced computed tomography (CECT). METHODS: We performed a prospective, multicenter, cohort study including 444 inpatients, 148 with cirrhosis (cohort 1) and 163 without cirrhosis (cohort 3) undergoing CECT and 133 with cirrhosis (cohort 2) unexposed to ICM. Kidney function parameters were assessed at T0, 48-72 h (T1), 5 and 7 days after CECT/enrollment. Urinary neutrophil gelatinase-associated lipocalin (U-NGAL) was measured in 50 consecutive patients from cohort 1 and 50 from cohort 2 as an early biomarker of tubular damage. RESULTS: AKI incidence was not significantly increased in patients with cirrhosis undergoing CECT (4.8%, 1.5%, 2.5% in cohorts 1, 2, 3 respectively, p = n.s.). Most AKI cases were mild and transient. The presence of concomitant infections was the only independent predictive factor of contrast-induced AKI (odds ratio 22.18; 95% CI 2.87-171.22; p = 0.003). No significant modifications of U-NGAL between T0 and T1 were detected, neither in cohort 1 nor in cohort 2 (median ΔU-NGAL: +0.2 [-7.6 to +5.5] ng/ml, +0.0 [-6.8 to +9.5] ng/ml, respectively [p = 0.682]). CONCLUSIONS: AKI risk after CECT in cirrhosis is low and not significantly different from that of the general population or of the cirrhotic population unexposed to ICM. It mostly consists of mild and rapidly resolving episodes of renal dysfunction and it is not associated with tubular kidney injury. Patients with ongoing infections appear to be the only ones at higher risk of AKI. IMPACT AND IMPLICATIONS: Nephrotoxicity due to intravenous iodinated contrast media (ICM) in patients with cirrhosis is still a debated issue, as the available evidence is limited and based on very heterogeneous studies, often conducted on small and retrospective cohorts. In this prospective three-cohort study we found that intravenous administration of ICM was associated with a low risk of AKI, similar to that of the general population and to that of patients with cirrhosis unexposed to ICM. Patients with ongoing infections were the only ones to have a significantly increased risk of contrast-induced AKI. Therefore, the actual recommendations of performing contrast imaging studies cautiously in cirrhosis do not seem to be reasonable anymore, with the exception of infected patients, who have a significantly higher risk of contrast-induced AKI.

Effects of fructan and gluten on gut microbiota in individuals with self-reported non-celiac gluten/wheat sensitivity-a randomised controlled crossover trial.

BACKGROUND: Individuals with non-celiac gluten/wheat sensitivity (NCGWS) experience improvement in gastrointestinal symptoms following a gluten-free diet. Although previous results have indicated that fructo-oligosaccharides (FOS), a type of short-chain fructans, were more likely to induce symptoms than gluten in self-reported NCGWS patients, the underlying mechanisms are unresolved. METHODS: Our main objective was therefore to investigate whether FOS-fructans and gluten affect the composition and diversity of the faecal microbiota (16S rRNA gene sequencing), faecal metabolites of microbial fermentation (short-chain fatty acids [SCFA]; gas chromatography with flame ionization detector), and a faecal biomarker of gut inflammation (neutrophil gelatinase-associated lipocalin, also known as lipocalin 2, NGAL/LCN2; ELISA). In the randomised double-blind placebo-controlled crossover study, 59 participants with self-reported NCGWS underwent three different 7-day diet challenges with gluten (5.7 g/day), FOS-fructans (2.1 g/day), and placebo separately (three periods, six challenge sequences). RESULTS: The relative abundances of certain bacterial taxa were affected differently by the diet challenges. After the FOS-fructan challenge, Fusicatenibacter increased, while Eubacterium (E.) coprostanoligenes group, Anaerotruncus, and unknown Ruminococcaceae genera decreased. The gluten challenge was primarily characterized by increased abundance of Eubacterium xylanophilum group. However, no differences were found for bacterial diversity (α-diversity), overall bacterial community structure (ß-diversity), faecal metabolites (SCFA), or NGAL/LCN2. Furthermore, gastrointestinal symptoms in response to FOS-fructans were generally not linked to substantial shifts in the gut bacterial community. However, the reduction in E. coprostanoligenes group following the FOS-fructan challenge was associated with increased gastrointestinal pain. Finally, correlation analysis revealed that changes in gastrointestinal symptoms following the FOS-fructan and gluten challenges were linked to varying bacterial abundances at baseline. CONCLUSIONS: In conclusion, while FOS-fructans induced more gastrointestinal symptoms than gluten in the NCGWS patients, we did not find that substantial shifts in the composition nor function of the faecal microbiota could explain these differences in the current study. However, our results indicate that individual variations in baseline bacterial composition/function may influence the gastrointestinal symptom response to both FOS-fructans and gluten. Additionally, the change in E. coprostanoligenes group, which was associated with increased symptoms, implies that attention should be given to these bacteria in future trials investigating the impact of dietary treatments on gastrointestinal symptoms. TRIAL REGISTRATION: Clinicaltrials.gov as NCT02464150.

Pre-clinical evaluation of biomarkers for the early detection of nephrotoxicity following alpha-particle radioligand therapy.

PURPOSE: Cancer treatment with alpha-emitter-based radioligand therapies (α-RLTs) demonstrates promising tumor responses. Radiolabeled peptides are filtered through glomeruli, followed by potential reabsorption of a fraction by proximal tubules, which may cause acute kidney injury (AKI) and chronic kidney disease (CKD). Because tubular cells are considered the primary site of radiopeptides' renal reabsorption and potential injury, the current use of kidney biomarkers of glomerular functional loss limits the evaluation of possible nephrotoxicity and its early detection. This study aimed to investigate whether urinary secretion of tubular injury biomarkers could be used as an additional non-invasive sensitive diagnostic tool to identify unrecognizable tubular damage and risk of long-term α-RLT nephrotoxicity. METHODS: A bifunctional cyclic peptide, melanocortin 1 ligand (MC1L), labeled with [203Pb]Pb-MC1L, was used for [212Pb]Pb-MC1L biodistribution and absorbed dose measurements in CD-1 Elite mice. Mice were treated with [212Pb]Pb-MC1L in a dose-escalation study up to levels of radioactivity intended to induce kidney injury. The approach enabled prospective kidney functional and injury biomarker evaluation and late kidney histological analysis to validate these biomarkers. RESULTS: Biodistribution analysis identified [212Pb]Pb-MC1L reabsorption in kidneys with a dose deposition of 2.8, 8.9, and 20 Gy for 0.9, 3.0, and 6.7 MBq injected [212Pb]Pb-MC1L doses, respectively. As expected, mice receiving 6.7 MBq had significant weight loss and CKD evidence based on serum creatinine, cystatin C, and kidney histological alterations 28 weeks after treatment. A dose-dependent urinary neutrophil gelatinase-associated lipocalin (NGAL, tubular injury biomarker) urinary excretion the day after [212Pb]Pb-MC1L treatment highly correlated with the severity of late tubulointerstitial injury and histological findings. CONCLUSION: Urine NGAL secretion could be a potential early diagnostic tool to identify unrecognized tubular damage and predict long-term α-RLT-related nephrotoxicity.

Plasma NGAL levels in stable kidney transplant recipients and the risk of allograft loss.

BACKGROUND: The objective of this study was to investigate the utility of neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin (CPT) to predict long-term graft survival in stable kidney transplant recipients (KTR). METHODS: A total of 709 stable outpatient KTR were enrolled >2 months post-transplant. The utility of plasma and urinary NGAL (pNGAL, uNGAL) and plasma and urinary CPT at enrollment to predict death-censored graft loss was evaluated during a 58-month follow-up. RESULTS: Among biomarkers, pNGAL showed the best predictive ability for graft loss and was the only biomarker with an area under the curve (AUC) > 0.7 for graft loss within 5 years. Patients with graft loss within 5 years (n = 49) had a median pNGAL of 304 [interquartile range (IQR) 235-358] versus 182 (IQR 128-246) ng/mL with surviving grafts (P < .001). Time-dependent receiver operating characteristic analyses at 58 months indicated an AUC for pNGAL of 0.795, serum creatinine-based Chronic Kidney Disease Epidemiology Collaboration estimated glomerular filtration rate (eGFR) had an AUC of 0.866. pNGAL added to a model based on conventional risk factors for graft loss with death as competing risk (age, transplant age, presence of donor-specific antibodies, presence of proteinuria, history of delayed graft function) had a strong independent association with graft loss {subdistribution hazard ratio (sHR) for binary log-transformed pNGAL [log2(pNGAL)] 3.4, 95% confidence interval (CI) 2.24-5.15, P < .0001}. This association was substantially attenuated when eGFR was added to the model [sHR for log2(pNGAL) 1.63, 95% CI 0.92-2.88, P = .095]. Category-free net reclassification improvement of a risk model including log2(pNGAL) in addition to conventional risk factors and eGFR was 54.3% (95% CI 9.2%-99.3%) but C-statistic did not improve significantly. CONCLUSIONS: pNGAL was an independent predictor of renal allograft loss in stable KTR from one transplant center but did not show consistent added value when compared with baseline predictors including the conventional marker eGFR. Future studies in larger cohorts are warranted.

Urine biomarkers individually and as a consensus model show high sensitivity and specificity for detecting UTIs.

BACKGROUND: Current diagnoses of urinary tract infection (UTI) by standard urine culture (SUC) has significant limitations in sensitivity, especially for fastidious organisms, and the ability to identify organisms in polymicrobial infections. The significant rate of both SUC "negative" or "mixed flora/contamination" results in UTI cases and the high prevalence of asymptomatic bacteriuria indicate the need for an accurate diagnostic test to help identify true UTI cases. This study aimed to determine if infection-associated urinary biomarkers can differentiate definitive UTI cases from non-UTI controls. METHODS: Midstream clean-catch voided urine samples were collected from asymptomatic volunteers and symptomatic subjects ≥ 60 years old diagnosed with a UTI in a urology specialty setting. Microbial identification and density were assessed using a multiplex PCR/pooled antibiotic susceptibility test (M-PCR/P-AST) and SUC. Three biomarkers [neutrophil gelatinase-associated lipocalin (NGAL), and Interleukins 8 and 1ß (IL-8, and IL-1ß)] were also measured via enzyme-linked immunosorbent assay (ELISA). Definitive UTI cases were defined as symptomatic subjects with a UTI diagnosis and positive microorganism detection by SUC and M-PCR, while definitive non-UTI cases were defined as asymptomatic volunteers. RESULTS: We observed a strong positive correlation (R2 > 0.90; p < 0.0001) between microbial density and the biomarkers NGAL, IL-8, and IL-1ß for symptomatic subjects. Biomarker consensus criteria of two or more positive biomarkers had sensitivity 84.0%, specificity 91.2%, positive predictive value 93.7%, negative predictive value 78.8%, accuracy 86.9%, positive likelihood ratio of 9.58, and negative likelihood ratio of 0.17 in differentiating definitive UTI from non-UTI cases, regardless of non-zero microbial density. NGAL, IL-8, and IL-1ß showed a significant elevation in symptomatic cases with positive microbe identification compared to asymptomatic cases with or without microbe identification. Biomarker consensus exhibited high accuracy in distinguishing UTI from non-UTI cases. CONCLUSION: We demonstrated that positive infection-associated urinary biomarkers NGAL, IL-8, and IL-1ß, in symptomatic subjects with positive SUC and/or M-PCR results was associated with definitive UTI cases. A consensus criterion with ≥ 2 of the biomarkers meeting the positivity thresholds showed a good balance of sensitivity (84.0%), specificity (91.2%), and accuracy (86.9%). Therefore, this biomarker consensus is an excellent supportive diagnostic tool for resolving the presence of active UTI, particularly if SUC and M-PCR results disagree.

Therapeutic potential of Lactobacillus casei and Chlorella vulgaris in high-fat diet-induced non-alcoholic fatty liver disease (NAFLD)-associated kidney damages: a stereological study.

BACKGROUND: The non-alcoholic fatty liver disease (NAFLD) is prevalent in as many as 25% of adults who are afflicted with metabolic syndrome. Oxidative stress plays a significant role in the pathophysiology of hepatic and renal injury associated with NAFLD. Therefore, probiotics such as Lactobacillus casei (LBC) and the microalga Chlorella vulgaris (CV) may be beneficial in alleviating kidney injury related to NAFLD. MATERIALS AND METHODS: This animal study utilized 30 C57BL/6 mice, which were evenly distributed into five groups: the control group, the NAFLD group, the NAFLD + CV group, the NAFLD + LBC group, and the NAFLD + CV + LBC group. A high-fat diet (HFD) was administered to induce NAFLD for six weeks. The treatments with CV and LBC were continued for an additional 35 days. Biochemical parameters, total antioxidant capacity (TAC), and the expression of kidney damage marker genes (KIM 1 and NGAL) in serum and kidney tissue were determined, respectively. A stereological analysis was conducted to observe the structural changes in kidney tissues. RESULTS: A liver histopathological examination confirmed the successful induction of NAFLD. Biochemical investigations revealed that the NAFLD group exhibited increased ALT and AST levels, significantly reduced in the therapy groups (p < 0.001). The gene expression levels of KIM-1 and NGAL were elevated in NAFLD but were significantly reduced by CV and LBC therapies (p < 0.001). Stereological examinations revealed reduced kidney size, volume, and tissue composition in the NAFLD group, with significant improvements observed in the treated groups (p < 0.001). CONCLUSION: This study highlights the potential therapeutic efficacy of C. vulgaris and L. casei in mitigating kidney damage caused by NAFLD. These findings provide valuable insights for developing novel treatment approaches for managing NAFLD and its associated complications.

Relationship between methylenetetrahydrofolate reductase C677T gene polymorphism and neutrophil gelatinase-associated lipocalin in early renal injury in H-type hypertension.

OBJECTIVE: To analyse the relationship between the polymorphisms of the H-type hypertensive methylenetetrahydrofolate reductase (MTHFR) C677T gene and neutrophil gelatinase-associated lipocalin (NGAL) in early kidney injury. METHOD: A total of 279 hospitalised patients with hypertension were selected and grouped according to their homocysteine (Hcy) level. If their blood Hcy level was ≥ 10 µmol/L they were assigned to the H-type hypertensive group, and if it was < 10 µmol/L they were assigned to the non-H-type hypertensive group. Blood lipid indexes, renal function indexes and blood glucose indexes were collected, and the differences between the two groups were compared. Furthermore, MTHFR C677T genotype distribution and allele frequency and Hcy level of MTHFR C677T genotype were compared, and logistic multiple regression analysis was conducted for the correlation of different genotypes of MTHFR C677T and the early kidney injury marker NGAL. RESULTS: In the non-H-type hypertensive group, the levels of Hcy and NGAL, cystatin, blood urea nitrogen, serum creatinine, uric acid, serum ß2-microglobulin and urinary microalbumin-to-creatinine ratio increased significantly, and the glomerular filtration rate level decreased significantly, when compared with the H-type hypertensive group, with statistical differences (p < 0.05). The H-type hypertensive group and the non-H-type hypertensive group had significant differences in the CC, CT and TT genotypes and allele frequencies at the MTHFR C677T locus. The MTHFR C677T gene mutation rate of the H-type hypertensive group was significantly higher than that of the non-H-type hypertensive group. The H-type hypertensive group had higher levels of the TT genotype and CT genotype Hcy. There was a statistical difference (p < 0.05). CONCLUSION: Methylenetetrahydrofolate reductase C677T polymorphism is correlated with the Hcy level, and its gene polymorphism will affect the Hcy level. Methylenetetrahydrofolate reductase C677T polymorphism has an interactive effect with NGAL. Screening NGAL and reducing Hcy levels are valuable methods for the prevention and treatment of early renal injury in patients with H-type hypertension and help improve the prognosis of patients and their quality of life.

Biomarkers for urinary tract infection: present and future perspectives.

A prompt diagnosis of urinary tract infection (UTI) is necessary to minimize its symptoms and limit sequelae. The current UTI screening by urine test strip analysis and microscopic examination has suboptimal diagnostic accuracy. A definitive diagnosis of UTI by urine culture takes two to three days for the results. These limitations necessitate a need for better biomarkers for the diagnosis and subsequent management of UTI in children. Here, we review the value of currently available UTI biomarkers and highlight the potential of emerging biomarkers that can facilitate a more rapid and accurate UTI diagnosis. Of the newer UTI biomarkers, the most promising are blood procalcitonin (PCT) and urinary neutrophil gelatinase-associated lipocalin (NGAL). PCT can provide diagnostic benefits and should be considered in patients who have a blood test for other reasons. NGAL, which is on the threshold of clinical care, needs more research to address its scope and utilization, including point-of-care application. Employment of these and other biomarkers may ultimately improve UTI diagnosis, guide UTI therapy, reduce antibiotic use, and mitigate UTI complications.

Furosemide stress test to predict acute kidney injury progression in critically ill children.

BACKGROUND: Furosemide stress test (FST) is a novel functional biomarker for predicting severe acute kidney injury (AKI); however, pediatric studies are limited. METHODS: Children 3 months to 18 years of age admitted to the intensive care unit (ICU) of a tertiary care hospital from Nov 2019 to July 2021 were screened and those who developed AKI stage 1 or 2 within 7 days of admission underwent FST (intravenous furosemide 1 mg/kg). Urine output was measured hourly for the next 6 h; a value > 2 ml/kg within the first 2 h was deemed furosemide responsive. Other biomarkers like plasma neutrophil gelatinase-associated lipocalin (NGAL) and proenkephalin (PENK) were also evaluated. RESULTS: Of the 480 admitted patients, 51 developed AKI stage 1 or 2 within 7 days of admission and underwent FST. Nine of these patients were furosemide non-responsive. Thirteen (25.5%) patients (eight of nine from FST non-responsive group) developed stage 3 AKI within 7 days of FST, nine (17.6%) of whom (seven from non-responsive group) required kidney support therapy (KST). FST emerged as a good biomarker for predicting stage 3 AKI and need for KST with area-under-the-curve (AUC) being 0.93 ± 0.05 (95% CI 0.84-1.0) and 0.96 ± 0.03 (95% CI 0.9-1.0), respectively. FST outperformed NGAL and PENK in predicting AKI stage 3 and KST; however, the combination did not improve the diagnostic accuracy. CONCLUSIONS: Furosemide stress test is a simple, inexpensive, and robust biomarker for predicting stage 3 AKI and KST need in critically ill children. Further research is required to identify the best FST cut-off in children.

Renal resistive index by point of care ultrasound to predict sepsis associated acute kidney injury in critically ill children.

BACKGROUND: Sepsis associated acute kidney injury (AKI) is linked with adverse outcomes in the PICU. Doppler-based renal resistive index (RRI) has shown promising results in adults for prediction of AKI. We aimed to explore the performance of RRI in children with sepsis. METHODS: This prospective observational study (March - November 2022) included children aged 1-12 years with sepsis admitted to the PICU. RRI and urine neutrophil gelatinase associated lipocalin (NGAL) were measured within 12 h of admission. Children were followed up for 3 days. AKI (new and persistent) was defined as any child with KDIGO stage 2 or 3 AKI on day 3. RESULTS: We enrolled 90 children but included 79 in final analysis. Two thirds (n = 53, 67%) had septic shock. Median (IQR) age was 6.2 years (4.1-9.2). RRI decreased with increasing age. Twenty-six (33%) children had AKI on day 3. Mean (SD) RRI was higher in the AKI group [0.72 (0.08) vs. 0.65 (0.07), p < 0.001].The area under ROC curve for RRI to detect AKI among the 1-4 year old group was 0.75 (95% CI:0.51, 0.98; p = 0.05) and among the 5-12 year old group was 0.76 (0.62, 0.89; p = 0.001). An RRI 0.71 predicted AKI with 100% sensitivity and 46.2% specificity among the 1-4-year-old group and RRI 0.69 predicted it with 70% sensitivity and 77.5% specificity in the 5-12-year-old group. RRI and eGFR at admission were independent predictors of AKI on multivariable analysis. Urine NGAL 94.8 ng/ml predicted AKI with 76.9% sensitivity and 77.4% specificity and AUROC was 0.74 (0.62, 0.86) among the 1-12-year-old group. CONCLUSIONS: RRI values varied with age. RRI showed good diagnostic accuracy to detect new/persistent AKI on day 3 in children with sepsis; however, it was less precise as an independent predictor.

Longitudinal NGAL and cystatin C plasma profiles present a high level of heterogeneity in a mixed ICU population.

BACKGROUND: NGAL and Cystatin C (CysC) as biomarkers for the early detection of AKI are subject to both pathophysiological, as well as patient related heterogeneity. The aim of this study was to investigate the timeline of plasma levels of NGAL and CysC during the first seven days of ICU admission in a mixed ICU population and to relate these to AKI severity during ICU stay. Via these means we aimed to bring clarity to the previously reported heterogeneity of these renal biomarkers. METHODS: Prospective Observation Cohort. Consecutive patients admitted to adult ICU at an academic hospital in the Netherlands between 18-02-2014 and 31-03-2014 were included. Urine output, serum creatinine, plasma NGAL and CysC were recorded during the first seven days of ICU admission. Biomarker expression was analyzed based on KDIGO score and time of AKI diagnosis. RESULTS: 335 patients were included, 110 met KDIGO criteria for AKI. NGAL and CysC plasma levels were higher in AKI patients compared to non-AKI, high variability in individual values resulted in 56% of AKI patients having a false negative, and 32% of non-AKI patients having a false positive. Individual biomarker levels were variable, and no pattern based on KDIGO score was observed. CONCLUSIONS: Plasma NGAL and CysC as biomarkers for the early AKI detection may be subject to pathophysiological, and patient related heterogeneity. Further understanding of individual biomarker profiles may help in their application amongst mixed ICU populations. TRIAL REGISTRATION: The need for informed consent was waived by the Institutional Ethical Review Board of the University Medical Center Groningen (METc 2013 - 174) by Prof. dr. W.A. Kamps on May 17th 2013.

Hypohydration induced by prolonged cycling in the heat increases biomarkers of renal injury in males.

PURPOSE: Recent studies have shown that hypohydration can increase renal injury. However, the contribution of hypohydration to the extent of renal injury is often confounded by exercise induced muscle damage. Therefore, the aim of the present study was to investigate the effect of manipulating hydration status during moderate-intensity cycling in the heat on biomarkers of renal injury. METHODS: Following familiarisation, fourteen active males (age: 21 [20-22] y; BMI: 22.1 ± 1.9 kg/m2; V ˙ O2peak: 55 ± 9 mL/kg/min) completed two experimental trials, in a randomised cross-over design. Experimental trials consisted of up to 120 min of intermittent cycling (~ 50% Wpeak) in the heat (~ 35 °C, ~ 50% relative humidity). During exercise, subjects consumed either a water volume equal to 100% body mass losses (EU) or minimal water (HYP; 75-100 mL) to induce ~ 3% body mass loss. Blood and urine samples were collected at baseline, 30 min post-exercise and 24 h post-baseline, with an additional urine sample collected immediately post-exercise. RESULTS: Thirty minutes post-exercise, body mass and plasma volume were lower in HYP than EU (P < 0.001), whereas serum and urine osmolality (P < 0.001), osmolality-corrected urinary kidney injury molecule-1 concentrations (HYP: 2.74 [1.87-5.44] ng/mOsm, EU: 1.15 [0.84-2.37] ng/mOsm; P = 0.024), and percentage change in osmolality-corrected urinary neutrophil gelatinase-associated lipocalin concentrations (HYP: 61 [17-141] %, EU: 7.1 [- 4 to 24] %; P = 0.033) were greater in HYP than EU. CONCLUSION: Hypohydration produced by cycling in the heat increased renal tubular injury, compared to maintaining euhydration with water ingestion.

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.

PURPOSE: 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. METHODS: We evaluated plasma neutrophil gelatinase-associated lipocalin (NGAL) and serum kidney injury molecule-1 (KIM1) before and after 180 min of moderate-intensity work (200 W/m2) in temperate (wet-bulb globe temperature [WBGT] 16 °C) and hot (32 °C) environments in healthy young (n = 13, 22 years) and older men (n = 12, 59 years), and older men with type 2 diabetes (T2D; n = 9, 60 years) or hypertension (HTN; n = 9, 60 years). RESULTS: 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 + 82 ng/mL; p < 0.001). Baseline concentrations of KIM1 were ~ 22 pg/mL higher in the older relative to young group, increasing by ~ 10 pg/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 ± 40 min) and HTN (108 ± 42 min), elevations in NGAL and KIM1 were similar to their healthy counterparts. CONCLUSION: 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.

Neutrophil Gelatinase-Associated Lipocalin for the Differentiation of Mucinous Pancreatic Cystic Lesions.

Undetermined pancreatic cystic lesion (PCL) differentiation benefits from endoscopic ultrasound (EUS) based on morphology and cyst fluid analysis, but room for new biomarkers exists. Our aim was to assess the intracystic and serum diagnostic value of neutrophil gelatinase-associated lipocalin (Ngal) and interleukin 1 beta (IL-1ß) for differentiation of PCLs. This prospective study included patients from one tertiary hospital, evaluated between April 2018 and May 2020. EUS fine-needle aspiration or pancreatic pseudocysts drainage was the source of PCL intracystic liquid. The final diagnosis was based on surgery or EUS results (morphology, cytology, glucose, and CEA-carcinoembryogenic antigen). The intracystic samples were tested for Ngal, IL-1ß, glucose, and CEA, and serum for Ngal and IL-1ß. We evaluated 63 cysts, 33 pseudocysts, and 30 non-inflammatory cysts. The diagnostic sensitivity and specificity for mucinous PCL was 70.8% and 92.3% for intracystic Ngal (cut-off: 500-800 ng/dL), without correlation with serum Ngal, no matter the inclusion of infected pseudocysts. After exclusion of infected pseudocysts, the sensitivity and specificity for glucose were 87% and 75%, respectively, and for CEA, they were 87.1%, and 96.8%, respectively. Intracystic Ngal shows promise in differentiating mucinous PCLs, but researchers need to conduct further studies to confirm its effectiveness. Intracystic IL-1ß and serum Ngal made no diagnostic contribution.

Associations between Microglia and Astrocytic Proteins and Tau Biomarkers across the Continuum of Alzheimer's Disease.

Recent investigations implicate neuroinflammatory changes, including astrocyte and microglia activation, as crucial in the progression of Alzheimer's disease (AD) Thus, we compared selected proteins reflecting neuroinflammatory processes to establish their connection to AD pathologies. Our study, encompassing 80 subjects with (n = 42) AD, (n = 18) mild cognitive impairment (MCI) and (n = 20) non-demented controls compares the clinical potential of tested molecules. Using antibody-based methods, we assessed concentrations of NGAL, CXCL-11, sTREM1, and sTREM2 in cerebrospinal fluid (CSF). Proinflammatory proteins, NGAL, and CXCL-11 reached a peak in the early stage of the disease and allowed for the identification of patients with MCI. Furthermore, the concentration of the anti-inflammatory molecule sTREM2 was highest in the more advanced stage of the disease and permitted differentiation between AD and non-demented controls. Additionally, sTREM2 was biochemically linked to tau and pTau in the AD group. Notably, NGAL demonstrated superior diagnostic performance compared to classical AD biomarkers in discriminating MCI patients from controls. These findings suggest that proteins secreted mainly through microglia dysfunction might play not only a detrimental but also a protective role in the development of AD pathology.

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.

The Expression of Markers of Acute Kidney Injury Kim1 and NGAL after Administration of High Doses of Lithium Carbonate in Mice with Engrafted Skin Melanoma B16.

The expression of marker proteins of acute kidney injury after administration of high doses of lithium carbonate was assessed to evaluate the possibility of lithium use in neutron capture therapy. In mice with implanted skin melanoma B16, the expression of Kim1 (kidney injury molecule 1) and NGAL (neutrophil gelatinase-associated lipocalin) proteins in the kidneys was evaluated immunohistochemically 15, 30, 90, 180 min, and 7 days after peroral administration of lithium carbonate at single doses of 300 and 400 mg/kg. An increase in the expression of the studied proteins was found in 30 and 90 min after administration of 400 mg/kg lithium carbonate, however, 7 days after the drug administration, the expression returned to the level observed in the control group. It can be suggested that single administration of lithium carbonate in the studied doses effective for lithium neutron capture therapy will not significantly affect the renal function.

IL-6 mediates the hepatic acute phase response after prerenal azotemia in a clinically defined murine model.

Prerenal azotemia (PRA) is a major cause of acute kidney injury and uncommonly studied in preclinical models. We sought to develop and characterize a novel model of PRA that meets the clinical definition: acute loss of glomerular filtration rate (GFR) that returns to baseline with resuscitation. Adult male C57BL/6J wild-type (WT) and IL-6-/- mice were studied. Intraperitoneal furosemide (4 mg) or vehicle was administered at time = 0 and 3 h to induce PRA from volume loss. Resuscitation began at 6 h with 1 mL intraperitoneal saline for four times for 36 h. Six hours after furosemide administration, measured glomerular filtration rate was 25% of baseline and returned to baseline after saline resuscitation at 48 h. After 6 h of PRA, plasma interleukin (IL)-6 was significantly increased, kidney and liver histology were normal, kidney and liver lactate were normal, and kidney injury molecule-1 immunofluorescence was negative. There were 327 differentially regulated genes upregulated in the liver, and the acute phase response was the most significantly upregulated pathway; 84 of the upregulated genes (25%) were suppressed in IL-6-/- mice, and the acute phase response was the most significantly suppressed pathway. Significantly upregulated genes and their proteins were also investigated and included serum amyloid A2, serum amyloid A1, lipocalin 2, chemokine (C-X-C motif) ligand 1, and haptoglobin; hepatic gene expression and plasma protein levels were all increased in wild-type PRA and were all reduced in IL-6-/- PRA. This work demonstrates previously unknown systemic effects of PRA that includes IL-6-mediated upregulation of the hepatic acute phase response.NEW & NOTEWORTHY Prerenal azotemia (PRA) accounts for a third of acute kidney injury (AKI) cases yet is rarely studied in preclinical models. We developed a clinically defined murine model of prerenal azotemia characterized by a 75% decrease in measured glomerular filtration rate (GFR), return of measured glomerular filtration rate to baseline with resuscitation, and absent tubular injury. Numerous systemic effects were observed, such as increased plasma interleukin-6 (IL-6) and upregulation of the hepatic acute phase response.

Melittin inhibits tumor cell migration and enhances cisplatin sensitivity by suppressing IL-17 signaling pathway gene LCN2 in castration-resistant prostate cancer.

BACKGROUND: Melittin is a small molecule polypeptide extracted from the abdominal cavity of bees, which is used to treat inflammatory diseases and relieve pain. However, the antitumor effect of melittin and its mechanisms remain unclear, especially in castration-resistant prostate cancer (CRPC). METHODS: Through CCK-8 assay, colony formation assay, wound healing assay and Transwell migration assay, we explored the effect of melittin on CRPC cell lines. In addition, with microarray analysis, gene ontology analysis and kyoto encyclopedia of genes and genomes analysis, this study identified key genes and signaling pathways that influence the growth of PC-3 cells. Meanwhile, the effect of melittin on CRPC was also verified through subcutaneous tumor formation experiments. Finally, we also tested the relevant indicators of human prostate cancer (PCa) specimens through immunohistochemistry and H＆E stating. RESULTS: Here, melittin was verified to inhibit the cell proliferation and migration of CPRC. Moreover, RNA-sequence analysis demonstrated that Interleukin-17 (IL-17) signaling pathway gene Lipocalin-2 (LCN2) was downregulated by melittin treatment in CRPC. Further investigation revealed that overexpression of LCN2 was able to rescue tumor suppression and cisplatin sensitivity which melittin mediated. Interestingly, the expression of LCN2 is highly related to metastasis in PCa. CONCLUSIONS: In brief, our study indicates that LCN2 plays an oncogenic role in CRPC and melittin may be selected as an attractive candidate for CRPC therapy.