Urinary N-acetyl-β-D-glucosaminidase Research Articles

Urinary N-Acetyl-β-d-Glucosaminidase (NAG) Levels and Risk of Cardiovascular Events in Diabetic Patients.

BackgroundCardiovascular diseases (CVDs) have a high incidence rate in population with diabetic patients. Studies on the association between urinary N-acetyl-β-d-glucosaminidase (NAG) levels, the biomarker of renal tubular damage, with cardiovascular (CV) events diabetic patients was still few.MethodsThe relationship between urinary NAG levels and CV events was analyzed in a prospective cohort including 357 patients with type 2 diabetes mellitus at a follow-up of 5 years.ResultsTwenty-six (7.3%) patients have CV events. Kaplan–Meier analysis suggested that diabetic patients with urine NAG levels ≥37.5 IU/L had a higher rate of CV events than those with urine NAG levels <37.5 IU/L (Log rank test, P = 0.021). Cox analysis revealed that elevated urine NAG levels significantly contributed to increased risk of CV events (HR = 1.43, 95% CI 1.23–1.93, P < 0.001) after adjusting for clinical confounding factors. Interestingly, we also found that “abnormal renal function” has an effect modification on the association between urine NAG levels and CV events. ROC-AUC analysis suggested that the urine NAG (AUC = 0.81, P < 0.001) had a better predictive value than eGFR (AUC = 0.74, P = 0.012).ConclusionElevated urine NAG levels are associated with higher risk of CV events in patients with type 2 diabetes. These results might further suggested that urinary NAG is a value urinary biomarker for early detecting CV events among diabetic patients.

The Role of Urinary N-Acetyl-β-d-glucosaminidase in Cirrhotic Patients with Acute Kidney Injury: Multicenter, Prospective Cohort Study.

Background and Aims: Currently, it is difficult to predict the reversibility of renal function and to discriminate renal parenchymal injury in cirrhotic patients with acute kidney injury (AKI). The aim of this study is to evaluate whether urine N-acetyl-β-d-Glucosaminidase (NAG) can predict the survival and response to terlipressin in cirrhotic patients with AKI. Methods: Two hundred sixty-two cirrhotic consecutive patients who developed AKI were prospectively enrolled from 11 tertiary medical centers in Korea between 2016 to 2019. AKI was defined as an increase in serum Cr (SCr) of 0.3 mg/dL or a 50% increase in baseline SCr. Patients diagnosed with hepatorenal syndrome (HRS-AKI) were treated with terlipressin plus albumin. Results: The patients were 58.8 ± 12.9 years old on average and were predominantly male (72.5%). The mean MELD score was 25.3 ± 9.1. When classified according to the AKI phenotype, there were 119 pre-renal, 52 acute tubular necrosis, 18 miscellaneous, and 73 HRS-AKI patients. However, the urine NAG was not effective at discriminating AKI phenotypes, except for HRS-AKI. The baseline urine NAG increased as the baseline AKI stage increased (p < 0.001). In addition, within the same AKI stage, the urine NAG values were significantly lower in the AKI-resolved group than in the unresolved group. The urine NAG level was significantly lower in living patients compared with those who died or who underwent a liver transplant within 3 months (p = 0.005). In the multivariate analysis, the increased urine NAG was a significant risk factor for the 3-month transplant-free survival (TFS) rate, especially in patients with Child–Pugh class ≤ B or MELD < 24. The urine NAG did not predict the response to terlipressin treatment in patients with HRS. Conclusions: Urine NAG is strongly associated with the severity of AKI in patients with liver cirrhosis and is useful for predicting the 3-month TFS.

Cadmium induces renal inflammation by activating the NLRP3 inflammasome through ROS/MAPK/NF-κB pathway in vitro and in vivo.

Cadmium (Cd) has been reported to induce kidney damage by triggering oxidative stress and inflammation. The NLR family Pyrin Domain Containing 3 (NLRP3) inflammasome has been implicated a role in the pathogenesis of inflammation. However, the connection between Cd and NLRP3 inflammasome in the development of renal inflammation remains unknown. In this study, in vitro experiments based on the telomerase-immortalized human renal proximal-tubule epithelial cell line (RPTEC/TERT1) were carried out. Results revealed that CdCl2 (2-8μM) increased ROS production and activated NLRP3, thereby enhancing secretion of IL-1β and IL-18 (P < 0.05). Knock-down of NLRP3 rescued the RPTEC/TERT1 cells from Cd-induced inflammatory damage. Cd activated the MAPK/NF-κB signaling pathway in RPTEC/TERT1 cells (P < 0.05). In addition, treatment with N-acetylcysteine (NAC) improved inflammation and blocked the upregulation of the MAPK/NF-κB signaling pathway. Pre-treatment with MAPK and NF-κB inhibitors also suppressed NLRP3 inflammasome activation (P < 0.05). Moreover, CdCl2 (25-00mg/L) stimulated the MAPK/NF-κB signaling pathway, activated the NLRP3 inflammasome, and increased inflammatory response (P < 0.05) leading to renal injury in rats. Exposure to cadmium elevated serum levels of NLRP3 and IL-1β in populations (P < 0.05). Further analysis found that serum NLRP3 and IL-1β levels were positively correlated with urine cadmium (UCd) and urine N-acetyl-β-D-glucosaminidase (UNAG). Overall, Cd induced renal inflammation through the ROS/MAPK/NF-κB signaling pathway by activating the NLRP3 inflammasome. Our research thus provides new insights into the molecular mechanism that NLRP3 contributes to Cd-induced kidney damage.

1299Association between environmental cadmium exposure and plasma and urinary metabolite profiles in Japanese cohort study

Abstract Background The purpose of this study was to identify plasma and urinary metabolites that can be used to better identify the effects of cadmium exposure than N-acetyl-β-D-glucosaminidase (NAG) using capillary electrophoresis - mass spectrometry (CE-MS). Methods Urinary cadmium (U-Cd) was measured as an indicator of cadmium exposure. Fasting plasma and urine samples were collected from 1,412 men and 2,022 women in Tsuruoka Metabolomics Cohort Study. Charged 94 plasma and 123 urinary metabolites were detected and determined. Regression analysis was performed for urinary NAG, plasma, and urinary metabolites as dependent variables and U-Cd in quartiles as an independent variable. Multivariate regression model included age, SBP, smoke, rice intake, BMI, HbA1c, LDLc, alcohol consumption, physical activity, educational history, dietary energy intake, urinary Na/K ratio, and uric acid. Results The mean U-Cd of the population was 2.65 μg/g creatinine (SD: 1.63). NAG was positively associated with U-Cd, but the association was not significant with lower U-Cd quartiles. In the plasma metabolites, 10 metabolites had significantly negative association with U-Cd in all models and Cd quartiles. Among urinary metabolites, 27 metabolites had significantly positive association with U-Cd. Alanine was negatively associated with U-Cd in urinary metabolites. The trend test also showed significant dose-response trends for 9 plasma and all 28 urinary metabolites (p &amp;lt; 0.05). Conclusions We found that the levels of Cd exposure, which did not cause an increase in NAG, caused changes in plasma and urinary metabolites. Key messages This study indicated that metabolomics might be promising and useful as markers of Cd exposure.

Environmental Exposure to Melamine-Related Compounds and Kidney Outcomes in Children

BACKGROUND AND AIM: Melamine is used in a variety of consumer and industrial applications, and exposure is ubiquitous. Melamine is a known nephrotoxicant in high doses, but it is unclear whether environmental levels or melamine analogues can impact pediatric kidney health. METHODS: We performed a cross-sectional study of 344 children (170 girls; 174 boys) aged 4-7 years within the GAPPS PATHWAYS Study relating urinary melamine, ammelide, and cyanuric acid (CA) concentrations with urinary concentrations of kidney injury-related biomarkers. Participants were recruited from an urban site (Seattle; n=163) and a rural site (Yakima; n=181) in Washington State. Biomarkers included total protein, albumin, creatinine, kidney injury molecule-1 (KIM-1), n-acetyl-β-D-glucosaminidase (NAG), neutrophil gelatinase-associated lipocalin (NGAL), and epidermal growth factor (EGF). Associations between melamine-related compounds and injury biomarkers were modeled in separate regressions controlling for specific gravity, urine collection time, study site, and sociodemographic factors. Additional regressions examined interactions by sex and site. RESULTS:Melamine, ammelide, and CA mean (SD) concentrations were 5.58 (11.8), 0.04 (0.10), and 49.0 (152.0) ng/mL, respectively. Compared to Seattle, Yakima participants had higher levels of ammelide and CA but lower levels of most kidney-related biomarkers. Girls had higher levels of most kidney-related biomarkers than boys. In the total population, ten-fold higher melamine was protectively associated with a 12.8% (95% CI: 1.55%, 25.4%) higher EGF and ten-fold higher CA was associated with 7.34% (2.43%, 12.0%) and 12.3% (0.02%, 23.1%) lower urinary total protein and NAG, respectively. Sex interaction analyses showed male-specific associations between melamine and higher KIM-1 as well as female-specific associations between ammelide and higher NAG and NGAL. Site interaction analyses showed that the associations with CA were specific to Yakima. CONCLUSIONS:These data suggest mixed associations between pediatric kidney health and melamine-related compounds that were at times sex-specific or site-specific. Potential public health implications of these findings require further study. KEYWORDS: Children’s environmental health, environmental epidemiology, molecular epidemiology, pesticides

The association between estimated glomerular filtration rate and cadmium exposure: An 8-year follow-up study.

The associations between cadmium exposure and chronic kidney disease have rarely been reported in longitudinal studies. In this study, we investigated the associations between the estimated glomerular filtration rate and cadmium exposure in a cross-sectional study in a longitudinal cohort. In total, 790 subjects (≥35 years of age) living in southeastern China were included at 1998. Cadmium in blood (BCd) and urine (UCd) as well as renal dysfunction biomarkers, urinary N-acetyl-β d-glucosaminidase (UNAG) and albumin (UALB), were determined. 497 subjects were followed at 2006 and a total of 456 subjects were finally included after excluding subjects that did not have exposure or effects biomarkers. The BCd, UCd, UNAG and UALB were determined using baseline methods. At follow-up, the estimated glomerular filtration rate (eGFR) was computed using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Single nucleotide polymorphisms (SNPs) in metallothioneins 1A (MT1A) rs11076161 and MT2A rs28366003 in blood sample were detected using TaqMan allelic discrimination assays. The median of UCd and BCd at baseline was 5.38μg/g cr and 4.69μg/L, respectively, and the median UCd and BCd at follow-up was 4.88μg/g cr and 2.20μg/L at follow-up. The mean eGFR at follow-up was 88.0mL/min/1.73m2 and 15 subjects had new onset of eGFR <60mL/min/1.73m2. The eGFR at follow-up was associated with baseline age (β=-0.66, 95% confidence interval (CI): 0.80 to -0.52), BCd (β=-0.46, 95% CI: 0.68 to -0.25) and UALB (β=-0.29, 95% CI: 0.41 to -0.16) after adjusting for confounders. Subgroup analysis in subjects who had low baseline UALB or subjects with or without hypertension showed similar results. A logistic regression model further showed that baseline BCd and UALB were independent risk factors for follow-up CKD. The odds ratios (ORs) were 1.09 (95% CI:1.03-1.16) for UALB, 1.16 (95% CI:1.01-1.33) for BCd, and 6.74 (0.87-29.63) for current hypertension. Baseline BCd, UALB and current hypertension were used to construct the nomogram. Linear discriminant analysis (LCA) showed that 87.6% of CKD was accurately predicted based on the three factors. Baseline age, BCd and UALB were associated with follow-up eGFR, and baseline BCd and UALB were predictive factors for incidence of CKD.

Elevated cadmium and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in residents living near electroplating industries.

This study aims to evaluate the body burdens of cadmium (Cd) associated with potential health impairment in residents living near electroplating industries. A total of 269 residents from exposure area and 106 from control area were recruited. We measured the blood and urinary Cd levels using an inductively coupled plasma mass spectrometer (ICP-MS); performed physical examinations; determined the urinary levels of β2-microglobulin (β2-MG), Nacetyl-β-D-glucosaminidase (NAG), and 8-hydroxy-2'-deoxyguanosine (8-OHdG); and evaluated the associations between Cd and these biomarkers. Blood and urinary Cd levels in exposure group were statistically higher than in control group (1.712 vs. 1.159 μg/L; 1.980 vs. 1.740 μg/L, respectively, p < 0.05). Urinary β2-MG and 8-OHdG levels in exposure group were also statistically higher (0.448 vs. 0.090 mg/L; 12.759 vs. 12.115 μg/L, respectively, p < 0.05), but urinary NAG levels showed no significant difference between the two groups (13.614 vs. 8.246 IU/L, p > 0.05). The proportion of abnormal nasal symptoms occurring in exposed subjects (88.8%) was much higher than in control subjects (78.2%, p < 0.05). Urinary Cd levels were positively correlated with blood Cd levels, urinary 8-OHdG, and NAG levels (r = 0.307, r = 0.185, r = 0.150, p < 0.05), but not correlated with urinary β2-MG levels (p > 0.05). In conclusion, our study revealed that residents living in close proximity to electroplating industries had elevated body burdens of Cd levels, as well as slight renal dysfunction and DNA oxidation damage.

Ginaton injection alleviates cisplatin-induced renal interstitial fibrosis in rats via inhibition of apoptosis through regulation of the p38MAPK/TGF-β1 and p38MAPK/HIF-1α pathways.

Ginaton injection (Ginkgo biloba extract; GBE) has been reported to protect against cisplatin-induced acute renal failure in rats. In the present study, the effects and molecular mechanisms of GBE on cisplatin-induced renal interstitial fibrosis were evaluated using a rat model. The rats were intraperitoneally injected with cisplatin once on the first day and a subset of rats were treated with GBE or SB203580 (SB; a specific p38 MAPK inhibitor) daily from days 22 to 40. The levels of N-acetyl-β-D-Glucosaminidase (NAG) in the urine, and of urea nitrogen (BUN) and creatinine (Scr) in the blood were assessed. The damage and fibrosis of renal tissues were evaluated using hematoxylin and eosin staining, as well as Masson's trichrome staining, respectively. Apoptosis in renal tissues was detected using a TUNEL assay. The protein expression levels of α-smooth muscle actin (SMA), collagen 1 (Col I), Bax, Bcl-2, caspase-3/cleaved caspase-3, hypoxia-inducible factor-1α (HIF-1α), TGF-β1 and p38MAPK, as well as the mRNA levels of p38MAPK in renal tissues were investigated. The results showed that GBE markedly reduced the levels of urinary NAG, Scr and BUN, and renal expression of α-SMA and Col I levels were also reduced. Furthermore, GBE significantly reduced renal tissue injury and the relative area of renal interstitial fibrosis induced by cisplatin. GBE effectively reduced the apoptotic rate of renal tissues, the protein expression levels of Bax, cleaved caspase-3, phospho-p38MAPK, TGF-β1 and HIF-1α, as well as the mRNA expression levels of p38MAPK in renal tissues induced by cisplatin, whereas GBE significantly increased Bcl-2 protein expression. SB exhibited similar effects to GBE, although it was not as effective. In summary, the present study is the first to show that GBE significantly alleviated renal interstitial fibrosis following cisplatin-induced acute renal injury. The mechanisms by which GBE exhibited its effects were associated with the inhibition of apoptosis via downregulation of the p38MAPK/TGF-β1 and p38MAPK/HIF-1α signaling pathways.

Association between plasma aldosterone and markers of tubular and glomerular damage in primary aldosteronism.

Although renal impairments are observed in patients with primary aldosteronism (PA), the association between plasma aldosterone concentration (PAC) and specific structural kidney damage remains unknown. Thus, we analysed the association between PAC, and markers of glomerular and tubular damage. This was a retrospective cross-sectional study of 96 PA patients, in which we analysed the association between PAC and markers of kidney damage, including urinary albumin-creatinine ratio (ACR) for glomerular damage, and urinary liver fatty acid-binding protein (L-FABP), N-acetyl-β-D-glucosaminidase (NAG) and β2-microglobulin (β2-MG) for tubular damage. In addition, we evaluated the association between PAC and N-terminal pro-brain natriuretic peptide (NT-proBNP) as a marker for body fluid volume. Urinary ACR, L-FABP, NAG, β2-MG and NT-proBNP significantly correlated with PAC. PAC (<415pmol/L, 415-550, 550-740, 740 <)-based quartile analysis revealed that both elevated markers of kidney damage and NT-proBNP could be observed in PA patients with a PAC over 550pmol/L. Logistic regression analysis showed that PAC was significantly associated with a risk of both microalbuminuria and lowered eGFR (<60mL/min/1.73m2 ), with its optimal cut-offs for predicting each, 558 and 594pmol/L, respectively. Increased PAC, especially over 550pmol/L, is associated with excessive damage to the tubule and glomerulus.

Pharmacokinetics-based chronoefficacy of Fuzi against chronic kidney disease.

Identifying drugs with time-varying efficacy or toxicity, and understanding the underlying mechanisms would help to improve treatment efficacy and reduce adverse effects. In this study, we uncovered that the therapeutic effect of Fuzi (the lateral root of Aconitum carmichaelii Debeaux) depended on the dosing time in mice with adenine-induced chronic kidney disease (CKD). The Fuzi efficacy was determined by biomarker measurements [i.e. plasma creatinine (CRE), blood urea nitrogen (BUN) and urinary N-acetyl-β-D-glucosaminidase (NAG)], as well as inflammation, fibrosis and histological analyses. Circadian regulation of Fuzi pharmacokinetics and efficacy was evaluated using brain and muscle Arnt-like protein-1 (Bmal1)-deficient (Bmal1-/-) mice. The Fuzi efficacy was higher when the drug was dosed at ZT10 and was lower when the drug was dosed at other times (ZT2, ZT6, ZT14, ZT18 and ZT22) according to measurements of plasma CRE, BUN and urinary NAG. Consistently, ZT10 (5 PM) dosing showed a stronger protective effect on the kidney (i.e. less extensive tubular injury) as compared to ZT22 (5 AM) dosing. This was supported by lower levels of inflammatory and fibrotic factors (IL-1β, IL-6, Tnf-α, Ccl2, Tgfb1 and Col1a1) at ZT10 than at ZT22. Pharmacokinetic analyses showed that the area under the curve (AUC) values (reflective of systemic exposure) and renal distribution of aconitine, hypaconitine and mesaconitine (three putative active constituents) for Fuzi dosing at ZT10 were significantly higher than those for herb dosing at ZT22, suggesting a role of circadian pharmacokinetics in Fuzi chronoefficacy. Drug efficacy studies confirmed that aconitine, hypaconitine and mesaconitine possessed a kidney-protecting effect. In addition, genetic knockout of Bmal1 in mice abolished the time-dependency of Fuzi pharmacokinetics and efficacy. This reinforced the existence of chronoefficacy for Fuzi and supported the role of circadian pharmacokinetics in Fuzi chronoefficacy. The efficacy of Fuzi against CKD depends on the dosing time in mice, which is associated with circadian pharmacokinetics of the three main active constituents (i.e. aconitine, hypaconitine and mesaconitine). These findings highlight the relevance of dosing time in the therapeutic outcomes of herbal medicines.

Nomogram to Predict Cadmium-Induced Osteoporosis and Fracture in a Chinese Female Population.

Cadmium exposure may increase the risk of osteoporosis. However, there is no quick method to get bone mineral density (BMD) unless dual-energy X-ray absorptiometry (DXA) examinations were performed. In the present study, we aimed to identify associated factors to osteoporosis and fracture in a Chinese female population with cadmium exposure and develop nomograms to predict the risk. A total of 488 women was included in this study. Cadmium in blood (BCd) and urine (UCd) were determined as exposure biomarkers. BMD was determined using single-photon absorptiometry. Urinary N-acetyl-β-d-glucosaminidase (UNAG) and urinary albumin (UALB) were determined as renal function biomarkers. Osteoporosis was defined if T-score < - 2.5. Multiple logistic regression showed that age, BCd, and menopausal status were independent risk factors for osteoporosis. The odds (OR) value was 1.19 (95% confidence interval (CI): 1.14-1.25) for age, 1.05 (95% CI: 1.004-1.10) for BCd, and 4.75 (95% CI: 1.65-13.69) for menopausal status after adjusting with cofounders. Age and UCd were the independent risk factors for bone fracture. Nomograms were developed based on the associated factors. Age was the main determinant for osteoporosis or fracture. Receiver operating curve showed acceptable performance in predicting osteoporosis (area under the curve (AUC) = 0.93, 95CI: 0.90-0.96) and fracture (AUC = 0.67, 95% CI: 0.58-0.75). Linear discriminant analysis (LDA) further showed that 88.9% of osteoporosis and 68.4% of fractures were correctly classified. Our study develops nomograms that may be used to predict cadmium-induced osteoporosis or fracture if BMD data is not available.

Study of Urinary N-Acetyl-Beta-D-Glucosaminidase as a biomarker of Diabetic Nephropathy

Background: Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients worldwide. Plenty of tubular damage biomarkers have been discovered. Urinary N-acetyl-β-D-glucosaminidase (NAG) is a hydrolytic enzyme that acts on glycosyl compounds. NAG is excreted in abnormally high amounts in many renal diseases. Objective: The aim of this work was to study the importance of Urinary N acetyl-β-D-glucosaminidase level as an early biomarker for detection of DN and to assess the degree of kidney affection in various stages of DN. Patients and methods: 100 subjects divided into five groups: Group 1: 20 healthy volunteers (control group), group 2: 20 pre diabetic persons, group 3: 20 normo-albuminuria diabetic patients, group 4: 20 micro-albuminuria diabetic patients (ACR 3 -300 mg/mmol) and group 5: 20 macro-albuminuria diabetic patients (ACR ≥ 300 mg/mmol). All individuals were subjected to full history taking, ECG & echocardiography, abdominal ultrasound, laboratory investigations (HbA1c, fasting and post prandial blood glucose, lipid profile, oral glucose tolerance test (OGTT), blood urea, serum creatinine, serum uric acid, e-GFR and urinary NAG. Results: There was high significant difference between the five groups regarding duration of the disease, fasting blood sugar, postprandial blood glucose, HbA1c, Serum cholesterol, albumin/creatinine ratio, serum urea and creatinine, e-GFR and urinary NAG. In addition, there was significant positive correlation between urinary NAG and albumin/creatinine ratio, blood urea, creatinine, and e-GFR. Conclusion: The urinary NAG can be used as an early urinary biomarker for early detection and progression of diabetic nephropathy in type 2 diabetic patients.

Study of Urinary N-Acetyl-Beta-D-Glucosaminidase as a biomarker of Diabetic Nephropathy

Background: Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients worldwide. Plenty of tubular damage biomarkers have been discovered. Urinary N-acetyl-β-D-glucosaminidase (NAG) is a hydrolytic enzyme that acts on glycosyl compounds. NAG is excreted in abnormally high amounts in many renal diseases. Objective: The aim of this work was to study the importance of Urinary N acetyl-β-D-glucosaminidase level as an early biomarker for detection of DN and to assess the degree of kidney affection in various stages of DN. Patients and methods: 100 subjects divided into five groups: Group 1: 20 healthy volunteers (control group), group 2: 20 pre diabetic persons, group 3: 20 normo-albuminuria diabetic patients, group 4: 20 micro-albuminuria diabetic patients (ACR 3 -300 mg/mmol) and group 5: 20 macro-albuminuria diabetic patients (ACR ≥ 300 mg/mmol). All individuals were subjected to full history taking, ECG & echocardiography, abdominal ultrasound, laboratory investigations (HbA1c, fasting and post prandial blood glucose, lipid profile, oral glucose tolerance test (OGTT), blood urea, serum creatinine, serum uric acid, e-GFR and urinary NAG. Results: There was high significant difference between the five groups regarding duration of the disease, fasting blood sugar, postprandial blood glucose, HbA1c, Serum cholesterol, albumin/creatinine ratio, serum urea and creatinine, e-GFR and urinary NAG. In addition, there was significant positive correlation between urinary NAG and albumin/creatinine ratio, blood urea, creatinine, and e-GFR. Conclusion: The urinary NAG can be used as an early urinary biomarker for early detection and progression of diabetic nephropathy in type 2 diabetic patients.

Utility of Urine N-acetyl-β-D-glucosaminidase for Prediction of Renal Damage in Obese Children.

The incidence of obesity has increased globally in children and adults. In addition, renal dysfunction is an important complication of childhood obesity. This study was performed to identify the diagnostic value of N-acetyl-β-D-glucosaminidase (NAG), a renal injury marker, for the early determination of renal damage in childhood obesity. Totally, 115 obese children and 115 healthy normal weight controls were enrolled in a cross-sectional case-control study. Urine NAG was measured in sample urine and normalized by urine creatinine (CR). In addition, correlation of urine NAG with other variables such as blood pressure (BP), blood glucose, and urine albumin was evaluated. Mean systolic BP (P <0.001), serum glucose (P = 0.047), urine albumin/Cr (P = 0.049), and urine NAG/Cr (P = 0.037) were significantly higher in obese children, compared with normal healthy controls. There was no correlation between urine NAG and urine albumin excretion. Urinary NAG/Cr was a simple and safe screening test for early determination of renal damage in children with obesity.

DNA aptamer raised against receptor for advanced glycation end products suppresses renal tubular damage and improves insulin resistance in diabetic mice.

Objective:Interaction of advanced glycation end products (AGEs) with the receptor RAGE plays a role in diabetic nephropathy. However, effects of RAGE-aptamer on tubular damage remain unknown. We examined whether RAGE-aptamer inhibited tubular damage in KKAy/Ta mice, obese type 2 diabetic mice with insulin resistance.Materials and Methods:Male 8-week-old KKAy/Ta mice received continuous intraperitoneal infusion of either control-aptamer or RAGE-aptamer for 8 weeks. Blood biochemistry and blood pressure, and urinary N-acetyl-β-D-glucosaminidase (NAG) activity and albumin excretion levels were monitored. Kidney and adipose tissue samples were obtained for immunohistochemical analyses.Results:Although RAGE-aptamer did not affect blood glucose, blood pressure, body weight, or serum creatinine values, it significantly inhibited the increase in urinary NAG activity and HOMA-IR in diabetic mice at 12 and 16 and at 16 weeks old, respectively. Furthermore, compared with control-aptamer-treated mice, renal carboxymethyllysine, RAGE, and NADPH oxidase-driven superoxide generation were significantly decreased in RAGE-aptamer-treated mice at 12 weeks old with subsequent amelioration of histological alterations in glomerular and interstitial area, while adipose tissue adiponectin expression was increased.Conclusion:Our present results suggest that RAGE-aptamer could inhibit tubular injury in obese type 2 diabetic mice partly by suppressing the AGE-RAGE-oxidative stress axis and improving insulin resistance.

Assessment of acute kidney injury by urinary β2-MG and NAG in pediatric cancer patients prescribed with Cisplatin, Carboplatin, and Ifosfamide as the chemotherapeutic agents

Background: Acute kidney injury (AKI) is defined as a failure in renal function leading to insufficiency of fluid and electrolyte homeostasis. Thus, sensitive biomarkers of renal tubular injury are needed to detect AKI earlier. In this study, urinary beta 2-microglobulin (β2-MG) and urinary N-acetyl-β-D-glucosaminidase (NAG) were evaluated for AKI prognosis/diagnosis in pediatric patients suffering different cancers prescribed with Ifosfamide, Ifosfamide plus Carboplatin, and Ifosfamide plus Cisplatin. Materials and Methods: In this prospective study done in Isfahan, Iran, urinary β2-MG, urinary NAG, blood urea nitrogen (BUN), and serum and urinary creatinine (Cr) were measured in 40 pediatric cancer patients less than 16 years old in three age groups during 61 courses of chemotherapy on day 0, three and six after the treatment. Results: Using ANOVA and t-test, the mean levels of urinary β2-MG (p= 0.001), urinary β2-MG/Cr (p= 0.003) and urinary NAG/Cr (p= 0.001), before and on day six of the treatment were statistically significant (p&lt; 0.05). Also, the mean levels of BUN (p= 0.01), urinary β2-MG (p= 0.001), β2-MG/Cr (p= 0.001) and NAG/Cr (p= 0.004) based on the gender groups, the mean levels of urinary NAG (p=0.001), NAG/Cr (p= 0.001) and β2-MG/Cr (p= 0.008) based on three age groups, and the mean levels of serum Cr (p= 0.047), urinary β2-MG (p= 0.005), β2-MG/Cr (p= 0.032) and NAG/Cr (p= 0.032) based on the Ifosfamide dosage were statistically significant during the time of the treatment. Conclusion: Urinary β2-MG, urinary β2-MG/Cr, and urinary NAG/Cr are more significant biomarkers than serum Cr in earlier diagnosis and treatment of AKI in cancer patients. However, urinary NAG should be further studied to prove its reliability for AKI prognosis/diagnosis. It is suggested that urinary NAG can be used along with other renal biomarkers such as urinary β2-MG, kidney injury molecule-1(KIM-1), or interleukin-18 (IL-18) for AKI prognosis/diagnosis.

Dynamics of Restoration of Functional State of the Kidney Parenchyma and Normalization of Main Risk Factors of Calcium-oxalate Nephrolithiasis in Urine on the Background of Using Complex Metaphylaxis

The objective: to investigate the dynamics of restoration of the functional state of the renal parenchyma by levels of N-acetyl-β-D-glucosaminidase (NAG) activity in urine and normalization of the main risk factors of calcium-oxalate nephrolithiasis (Ca-Ox NL) – by concentrations of calcium, oxalic and uric acids in urine on the background of application of complex metaphylaxis within a year after stone removal.Materials and methods. 45 patients with Ca-Ox NL before and after the removal of concrements in 1, 3, 6 and 12 months on the background of the use of complex metaphylaxis were examined. The activity of the conditionally renospecific enzyme NAG and concentration of calcium, oxalic and uric acids were analyzed. The personification of metaphylactic measures was performed depending on the characteristics of the risk factors for the development of Ca-Ox NL: the combination of hyperoxaluria with hyperuricemia and hyperuricuria, the combination of hyperoxaluria with hyperuricemia, the presence of significant hyperoxaluria on the background of normouricemia and normouricuria and also depending on hypercalciuria. The control group consisted of 28 practically healthy persons with normal analysis of urine and free of renal diseases.Results. In patients with NL before the removal of the stone, the activity of NAG, calcium, oxalic and uric acid concentrations probably exceeded the control data. In the dynamics of observation there is a gradual decrease in urinary NAG activity, calcium, oxalic and uric acid concentrations. NAG activity and uric acid concentration did not differ from the data in the control group after 12 months, calcium – after 3 months, oxalic acid concentration after 6 months.Conclusion. Restoration of the functional state of tubular nephrotheoia and normalization of concentrations of the main risk factors for the development of Ca-Ox NL on the background of complex metaphylaxis was achieved in almost 95 % of cases. The obtained results can be used to correct and optimize the treatment tactics of patients with Ca-Ox NL after removal of the calculus during the year.

Enzymologic Indicators of Ischemic Damage to the Kidney Parenchyma in Patients with Urolithiasis (Clinical Experimental Study)

The objective: was to determine in the urine of patients with calcium-oxalate nephrolithiasis (Ca-Ox NL) and phosphoric acid nephrolithiasis PhAU) and in the rabbit kidney parenchyma with simulated ischemia, the activity of lysosome enzymes N-acetyl-β-D-glucosaminidase (NAG) and β-galactosidase (β-Gal) as enzymatic indicators of the ischemic origin of the kidney parenchyma.Materials and methods. In the urine of 151 patients with nephrolithiasis with preserved renal function (45 with Ca-Ox NL and 106 with PhANL), the activity of the lysosomal enzymes NAG and β-Gal was examined. Patients are divided into groups depending on the type of NL, the size of the calculus and its mineral composition. The reference group – 25 healthy persons. An experimental study was conducted on 10 rabbits with modeled left kidney ischemia, which developed 3.5 to 5.0 months after ligature was applied to its upper pole, and 3 healthy rabbits (6 kidneys). The activity of NAG and β-Gal was determined in the homogenate of the cortical layer of the upper pole of the ischemic kidney and the kidneys of healthy rabbits.Results. All patients with nephrolithiasis have ischemic damage to the kidney parenchyma of varying severity. The most significant ischemic damage to the kidney parenchyma by calculus according to the definition of NAG and β-Gal was recorded in patients with PhANL with magnesium-containing calculi, which had the largest stone sizes. In the experiment on rabbits, a significant decrease in the enzyme activity in the renal parenchyma of animals with ischemia was shown to be compared with similar parameters in healthy rabbits.Conclusion. The results obtained indicate the feasibility of determining the activity of lysosomal enzymes of urine NAG and β-Gal as non-invasive enzyme indicators of ischemic damage to the tubular epithelium of the kidney in patients with nephrolithiasis, which is confirmed by experimental studies. The severity of ischemic damage to the kidney parenchyma in patients with nephrolithiasis according to the determination of the activity of the NAG and β-Gal enzymes in urine depends on the type of nephrolithiasis, the size of the calculus and its mineral composition.

Effect of non-steroidal anti-inflammatory drugs on glomerular filtration rate and urinary N-acetyl-β-D-glucosaminidase activity in cats after dental surgery

ObjectiveTo compare the effects of meloxicam or carprofen on glomerular filtration rate (GFR), and to evaluate the effect of meloxicam on urinary N-acetyl-β-D-glucosaminidase (NAG) activity, of cats after dental surgery. Study designRandomized, blinded, controlled trial. AnimalsA total of 24 mixed breed cats. MethodsCats were randomly assigned to one of three groups (n = 8 per group): meloxicam (0.2 mg kg–1); carprofen (4 mg kg–1); or saline (2 mL). Acepromazine (0.04 mg kg–1) and buprenorphine (0.02 mg kg–1) were administered intramuscularly as preanaesthetic medication. Test drugs were injected subcutaneously at the time of preanaesthetic medication. Anaesthesia was induced with intravenous propofol and maintained with isoflurane in oxygen. Mean arterial blood pressure (MAP), respiratory rate (fR), heart rate (HR) and haemoglobin oxygen saturation values (SpO2) were recorded. All cats underwent ultrasonic dental scaling with polishing. Teeth extraction involved mucosal flap creation, removal of alveolar bone and flap closure. Plasma iohexol clearance (ICL), a measure of GFR, was estimated before and 24 hours after anaesthesia induction in all cats. Urinary NAG index was estimated in saline and meloxicam groups at the same time points as GFR. Between-group and -time point differences in GFR and NAG index were compared using mixed model analyses. Data are presented as mean ± standard deviation (p < 0.05). ResultsThere was no significant difference in plasma ICL rate (range: from 1.22 ± 0.05 to 1.27 ± 0.04 mL kg minute–1) between groups or between time points. Urinary NAG index (range: from 1.0 ± 0.19 to 1.36 ± 0.29 Units gram–1) was not significantly different between meloxicam and saline groups. MAP, HR, fR and SpO2 did not differ significantly between groups. Conclusions and clinical relevanceMeloxicam and carprofen appeared to produce nonsignificant effects on GFR, and meloxicam did not affect the urinary NAG activity, of cats after dental surgery.

Diagnostic value of combined detection of four-item urinary protein for early hypertensive kidney injury

Objective To investigate the diagnostic value of combined detection of urine α1-microglobulin(α1-mG), N-acetyl-β-D-glucosaminidase (NAG), retinol binding protein (RBP) and β2-microglobulin (β2-mG) for early hypertensive kidney injury. Methods From June 2016 to December 2018, 116 hypertension patients with renal damage (HRD group) and 44 cases with simple hypertension(HBP group) were selected in the Central People′s Hospital of Tengzhou in this study.And 36 cases of healthy people during the same period were selected as the control group.One hundred and sixteen cases of the HRD group were divided into Ⅰ-Ⅱ group (61 cases) and Ⅲ-Ⅴ group (55 cases) according to the classification of chronic kidney disease(CKD). The concentrations of α1-mG, NAG, RBP and β2-mG in urine were detected in patients and healthy people respectively.SPSS 19.0 software was used to perform statistical analysis. Results The concentrations of urine α1-mG, NAG, RBP, β2-mG in the HRD group were (41.77±24.21)mg/L, (22.60±13.24)U/L, (2.86±1.73)mg/L, (1.76±0.95)mg/L, respectively, which in the HBP group were (12.49±8.10)mg/L, (13.45±8.61)U/L, (0.31±0.16)mg/L, (0.38±0.38)mg/L, respectively, which in the control group were (4.37±2.52)mg/L, (6.12±3.57)U/L, (0.29±0.17)mg/L, (0.28±0.15)mg/L, respectively.The concentrations of urine α1-mG, NAG, RBP, β2-mG in the HRD group were significantly higher than those in the HBP group(t=4.07, 4.25, 4.09, 4.03, all P<0.05) and the control group(t=3.15, 4.94, 2.49, 2.61, all P<0.05). The urine levels of α1-mG, NAG, RBP, β2-mG in phase Ⅰ-Ⅱ group were (21.62±13.45)mg/L, (21.96±12.49)U/L, (0.5±0.47)mg/L, (0.93±0.62)mg/L, respectively, which in the phase Ⅲ-Ⅴ group were (64.11±60.12)mg/L, (23.32±14.11)U/L, (5.48±4.77)mg/L, (2.68±2.55)mg/L, respectively.The concentrations of urine α1-mG, NAG, RBP and β2-mG in Ⅰ-Ⅱ group (t=5.08, 4.99, 2.96, 1.66, all P<0.05) and Ⅲ-Ⅴ group (t=3.95, 4.81, 4.33, 3.74, all P<0.05) were significantly higher than those in the control group.The levels of α1-mG, RBP and β2-mG in group Ⅲ-Ⅴ were higher than those in group Ⅰ-Ⅱ(t=5.37, 8.11, 4.52, all P<0.05). The positive detection rates of α1-mG, NAG, RBP, β2-mG and combination test in phase Ⅰ-Ⅱ group were 70.5%, 77.0%, 19.7%, 60.7%, 91.8%, respectively, which in the phase Ⅲ-Ⅴ group were 81.8%, 81.8%, 69.1%, 69.1% and 96.4%, respectively.The positive rate of urine α1-mG, NAG, RBP and β2-mG combination test was significantly higher than that of the single detection (phase Ⅰ-Ⅱ group: χ2=7.71, 3.99, 61.4, 14.65; phase Ⅲ-Ⅴ group: χ2=4.58, 4.58, 12.47, 12.47; all P<0.05). Conclusion Urine α1-mG, NAG, RBP and β2-mG are important biochemical indicators in patients with early hypertensive kidney injury.The combined detection of the four tests has high diagnostic value in the diagnosis of early hypertensive nephropathy. Key words: Hypertension; Urine protein; Early hypertensive kidney injury; α1-microglobulin; N-acetyl-β-D-glucosaminidase; Retinol binding protein; β2-microglobulin; Combined detection