Tubular Impairment Research Articles

Deficiency of thiosulfate sulfurtransferase mediates the dysfunction of renal tubular mitochondrial fatty acid oxidation in diabetic kidney disease.

One of the main characteristics of diabetic kidney disease (DKD) is abnormal renal tubular fatty acid metabolism, especially defective fatty acid oxidation (FAO), accelerating tubular injury and tubulointerstitial fibrosis. Thiosulfate sulfurtransferase (TST), a mitochondrial enzyme essential for sulfur transfer, is reduced in metabolic diseases like diabetes and obesity. However, the potential role of TST in regulating fatty acid metabolic abnormalities in DKD remains unclear. Here, our data revealed decreased TST expression in the renal cortex of DKD patients. TST deficiency exacerbated tubular impairment in both diabetic and renal fibrosis mouse models, while sodium thiosulfate treatment or TST overexpression mitigated renal tubular injury with high-glucose exposure. TST downregulation mediated the decrease in S-sulfhydration of very long-chain specific acyl-CoA dehydrogenase, resulting in mitochondrial FAO dysfunction. This sequence of events exacerbates the progression of tubulointerstitial injury in DKD. Together, our findings demonstrate TST as a regulator of renal tubular injury in DKD.

Notoginsenoside Fc ameliorates renal tubular injury and mitochondrial damage in acetaminophen-induced acute kidney injury partly by regulating SIRT3/SOD2 pathway.

Mitochondria dysfunction is one of the primary causes of tubular injury in acute kidney injury (AKI). Notoginsenoside Fc (Fc), a new saponin isolated from Panax notoginseng, exhibited numerous pharmacological actions. However, the beneficial effects of Fc on renal tubular impairment and mitochondrial dysfunction in AKI have not been fully studied. In this study, we established acetaminophen (APAP)-induced AKI model in mice to examine the therapeutic impacts of Fc on AKI. Our results showed that Fc could decrease the levels of the serum creatinine (Scr), blood urea nitrogen (BUN) and Cystatin C in mice with AKI. Fc also ameliorated renal histopathology, renal tubular cells apoptosis and restored expression of apoptosis-related proteins such as Bax, Bcl-2 and caspase3 (C-caspase3). Additionally, Fc increased the protein expression of SIRT3 and SOD2 in kidneys from mice with AKI. In vitro studies further showed Fc reduced the apoptosis of HK-2 cells exposure to APAP, attenuated the loss of mitochondrial membrane potential and decreased the formation of mitochondrial superoxide. Fc also partly restored the protein expression of Bax, Bcl-2, C-Caspase3, SIRT3, and SOD2 in HK-2 cells exposure to APAP. In summary, Fc might reduce renal tubular injury and mitochondrial dysfunction in AKI partly through the regulation of SIRT3/SOD2 pathway.

Urinary RBP as an Independent Predictor of Renal Outcome in Diabetic Nephropathy.

Background Renal tubular impairment is prevalent in diabetic nephropathy (DN) and the histological severity predicted renal outcome. Biomarkers of tubular injury also increased in the urine of DN patients. The retrospective study aimed to assess the prognostic value of clinically widely applied urinary tubular injury markers, retinol-binding protein (RBP), β2-microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) in DN. Method A total of 305 patients with biopsy-proven DN were enrolled. The baseline urine total protein and components including albumin, IgG, RBP, β2-MG and NAG were retrieved from medical records. The primary outcome was end stage renal disease (ESRD). Cox proportional hazard analysis and restricted cubic splines were performed to evaluate the association of parameters with ESRD. Nomograms were constructed and concordance index (C-index) was used to measure the prediction ability. Result The levels of urinary RBP, β2-MG and NAG were positively correlated with the severity of interstitial fibrosis and tubular atrophy (IFTA). Positive correlations were also observed among β2-MG, NAG and mesangial expansion. Urinary RBP was not correlated with any glomerular lesions. Urinary RBP, β2-MG and NAG were risk factors for ESRD in hazard analysis with adjustment for age, gender and body mass index (BMI). The hazard ratios increased with the increment of baseline levels. In the multivariate Cox model including serum creatinine (SCr), total urinary protein, urinary albumin, urinary IgG and the tubular injury biomarkers, urinary RBP (with every g/mol.Cr increase: HR 1.06, 95% CI 1.03-1.10, p =0.001) remained as an independent risk factor for ESRD in DN patients. Patients were divided by the medium value of urinary RBP into the low RBP and high RBP groups. Survival analysis showed that significantly more patients in the high RBP progressed to ESRD compared to those in the low RBP group (p =0.02) when urinary total protein was less than 3.5 g/g. The C-index of the nomogram incorporating age, gender, BMI, SCr and total urine protein was 0.757. The value increased to 0.777 after adding urinary RBP to the model. Conclusions Urinary RBP excretion was only correlated with the severity of IFTA and independently predicted ESRD in DN patients.

Formononetin Attenuates Renal Tubular Injury and Mitochondrial Damage in Diabetic Nephropathy Partly via Regulating Sirt1/PGC-1α Pathway.

Mitochondrial abnormality is one of the main factors of tubular injury in diabetic nephropathy (DN). Formononetin (FMN), a novel isoflavonoid isolated from Astragalus membranaceus, has diverse pharmacological activities. However, the beneficial effects of FMN on renal tubular impairment and mitochondrial dysfunction in DN have yet to be studied. In this study, we performed in vivo tests in Streptozotocin (STZ) -induced diabetic rats to explore the therapeutic effects of FMN on DN. We demonstrated that FMN could ameliorate albuminuria and renal histopathology. FMN attenuated renal tubular cells apoptosis, mitochondrial fragmentation and restored expression of mitochondrial dynamics-associated proteins, such as Drp1, Fis1 and Mfn2, as well as apoptosis-related proteins, such as Bax, Bcl-2 and cleaved-caspase-3. Moreover, FMN upregulated the protein expression of Sirt1 and PGC-1α in diabetic kidneys. In vitro studies further demonstrated that FMN could inhibit high glucose-induced apoptosis of HK-2 cells. FMN also reduced the production of mitochondrial superoxide and alleviated mitochondrial membrane potential (MMP) loss. Furthermore, FMN partially restored the protein expression of Drp1, Fis1 and Mfn2, Bax, Bcl-2, cleaved-caspase-3, Sirt1 and PGC-1α in HK-2 cells exposure to high glucose. In conclusion, FMN could attenuate renal tubular injury and mitochondrial damage in DN partly by regulating Sirt1/PGC-1α pathway.

Persistent/progressive subclinical contrast-induced nephropathy – predictors and effects of parenteral hydration. A prospective study in patients undergoing coronary angioplasty

Abstract Background In most cases, contrast-induced nephropathy (CIN) appears to be a transient event. The pathophysiology of CIN, which includes renal vasoconstriction and hypoxia, generation of cytotoxic reactive oxygen species, and even direct tubular toxicity, suggests however that the tubular impairment typical for CIN may not be entirely transient and that persistent/progressive subclinical kidney dysfunction could actually occur. Purpose We aimed to evaluate the incidence, identify the predictors, and assess the impact of parenteral hydration on the occurrence of persistent/progressive subclinical CIN in patients undergoing coronary angioplasty. Methods A total of 71 patients scheduled for elective coronary angioplasty were randomized into two groups: Control (n=36) and HYD (n=35). Patients in the HYD group received prophylactic hydration with saline solution (1 ml/kg/h; 6 h prior to and 12 h after the procedure). Plasma levels of neutrophil gelatinase-associated lipocalin (NGAL), a specific marker of tubular impairment, were evaluated prior to, and 48 h and 1 month after the angioplasty procedure. Persistent/progressive subclinical CIN at 1 month post-angioplasty was defined as a significant increase in NGAL at 48 h after the procedure that persisted (i.e., did not change by more than 10%) or aggravated (i.e., increased by more than 10%) at 1 month follow-up. The ability of several factors (i.e., age, hypertension, diabetes, use of nephrotoxic drugs, baseline creatinine clearance, volume of contrast agent) to predict persistent/progressive CIN was evaluated. The ability of parenteral hydration to prevent persistent/progressive CIN was also assessed. Results According to the current criteria, CIN was present in 5 (7.0%) patients. Meanwhile, subclinical CIN was identified in 36 (50.7%) patients, of which 10 (27.7%) presented persistent and 15 (41.6%) progressive CIN at 1 month follow-up. The volume of contrast administered during angioplasty was the only factor that differed significantly between patients who developed persistent/progressive CIN and those who did not (178±17 mL vs. 130±10 mL, p=0.01). In ROC analysis, contrast volume ≥150 mL predicted persistent/progressive CIN with 77% sensitivity and 60% specificity (p<0.001). Prophylactic hydration was associated with a 75% lower risk of persistent/progressive CIN (RR 0.25; 95% CI 0.09–0.65; p=0.001). Conclusions Despite the relatively low incidence of CIN, subclinical CIN was identified in more than 50% of the study patients. More than 2/3 of these patients presented persistent or progressive subclinical CIN at 1 month follow-up. The clinical impact of this persistent/progressive subclinical CIN in patients undergoing multiple contrast administrations remains to be established. Our data indicate that reducing the contrast volume and/or using prophylactic parenteral hydration can significantly reduce persistent/progressive subclinical CIN. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS-UEFISCDI

Relationship of urinary liver-type fatty acid-binding protein with cardiovascular risk factors in the Japanese population without chronic kidney disease: Sasayama study

BackgroundUrinary liver-type fatty acid-binding protein (L-FABP) is a well-known marker of proximal tubular impairment. We evaluated the relationship between cardiovascular disease (CVD) risk factors and levels of L-FABP in a cross-sectional community-based study. Participants with normoalbuminuria and normal estimated glomerular filtration rate (eGFR), that is, non-chronic kidney disease (non-CKD), were enrolled in this study. To the best of our knowledge, this is the first study to focus on the association between CVD risk factors and a proximal tubular marker in the Japanese general population with normoalbuminuria and normal eGFR.MethodsThe present study is part of the Sasayama study. The participants included 1000 community residents (447 men and 553 women) aged 40–64 years without a history of CVD or renal dysfunction. Out of these participants 375 men and 477 women, defined as non-CKD, were included for further analysis. In each sex, the highest quintile group was considered to have high-normal L-FABP levels. A multiple logistic regression model was used to evaluate the relationship between risk factors for CVD and high-normal L-FABP levels in the non-CKD participants. We performed a similar analysis using the high-normal urinary albumin to creatinine ratio (UACR) as a dependent variable instead of L-FABP.ResultsAmong the non-CKD participants, in the highest quintile group (Q5, top 20%), L-FABP was ≥2.17 μg/gCre in men and ≥ 2.83 μg/gCre in women. In women, the multivariate odds ratio was 3.62 (1.45–9.00) for high-normal L-FABP in the presence of diabetes mellitus (DM) compared with that in the group without DM. However, the relationship between DM and the UACR level was not significant. In men, DM was significantly associated with high-normal UACR. However, the relationship with L-FABP levels was not significant.ConclusionsThe presence of DM was more strongly related to high-normal L-FABP levels than to high-normal UACR in women even at the stage of normoalbuminuria and normal eGFR. Our results were also consistent with the findings of a previous study where women were more prone to nonalbuminuric renal impairment compared to men, although further studies are required to confirm the results.

Influence of maternal use of tenofovir disoproxil fumarate or zidovudine in Vietnamese pregnant women with HIV on infant growth, renal function, and bone health.

Tenofovir disoproxil fumarate (TDF) is still widely prescribed for human immunodeficiency virus (HIV)-infected pregnant women, despite its renal and bone toxicity. Although TDF-exposed infants often show transient growth impairment, it is not clear whether maternal TDF causes infantile rickets via maternal/fetal renal dysfunction in Asian populations. This prospective observational study was conducted in Vietnam and involved pregnant HIV-infected women treated with TDF-based regimen (TDF group) or zidovudine-based regimen (AZT-group). At birth, 3, 12, and 18 months of age, and included body length, weight, head circumference, serum alkaline phosphatase (ALP), creatinine, calcium, phosphorus, urine-β2-microglobulin (U-BMG), percentage of tubular reabsorption of phosphate (%TRP), and radiographic wrist score for rickets. Age-adjusted multivariate linear regression analysis evaluated the association of TDF/AZT use during pregnancy with fetal renal function and bone health. The study included 63 mother-infant pairs (TDF group = 53, AZT group = 10). In the mothers, detectable U-BMG (>252 μg/L) was observed more frequently in the TDF- than AZT group (89 vs 50%, p<0.001), but other renal/bone parameters were similar. In infants, maternal TDF use was not associated with growth impairment, renal dysfunction, or abnormal bone findings, but with a slightly higher ALP levels (p = 0.019). However, shorter length was associated with maternal AZT (p = 0.021), and worse radiographic scores were associated with LPV/r (p = 0.024). In Vietnamese population, TDF usage during pregnancy was not associated with infant transient rickets, growth impairment, or renal dysfunction, despite mild maternal tubular impairment. Maternal AZT and LPV/r influenced infant growth and bone health, though further studies are needed to confirm this finding.

Kidney Diseases: The Age of Molecular Markers.

Kidney diseases are conditions that increase the morbidity and mortality of those afflicted. Diagnosis of these conditions is based on parameters such as the glomerular filtration rate (GFR), measurement of serum and urinary creatinine levels and equations derived from these measurements (Wasung, Chawla, Madero. Clin Chim Acta 438:350-357, 2015). However, serum creatinine as a marker for measuring renal dysfunction has its limitations since it is altered in several other physiological situations, such as in patients with muscle loss, after intense physical exercise or in people on a high protein diet (Riley, Powers, Welch. Res Q Exerc Sport 52(3):339-347, 1981; Juraschek, Appel, Anderson, Miller. Am J Kidney Dis 61(4):547-554, 2013). Besides the fact that serum creatinine is a marker that indicates glomerular damage, it is necessary the discovery of new biomarkers that reflect not only glomerular damage but also tubular impairment. Recent advances in Molecular Biology have led to the generation or identification of new biomarkers for kidney diseases such as: Acute Kidney Failure (AKI), chronic kidney disease (CKD), nephritis or nephrotic syndrome. There are recent markers that have been used to aid in diagnosis and have been shown to be more sensitive and specific than classical markers, such as neutrophil gelatinase associated lipocalin (NGAL) or kidney injury molecule-1 (KIM-1) (Wasung, Chawla, Madero. Clin Chim Acta 438:350-357, 2015; George, Gounden. Adv Clin Chem 88:91-119, 2019; Han, Bailly, Abichandani, Thadhani, Bonventre. Kidney Int 62(1):237-244, 2002; Fontanilla, Han. Expert Opin Med Diagn 5(2):161-173, 2011). However, early diagnostic biomarkers are still necessary to assist the intervention and monitor of the progression of these conditions.

Acute Hyperglycemia May Induce Renal Tubular Injury Through Mitophagy Inhibition.

AimAcute hyperglycemia is closely related to kidney injury. Oxidative stress activation and notable mitochondria damages were found under acute hyperglycemia treatment in our previous work. In the present study, we explored the dose-effect relationship and the pivotal role of mitophagy in acute hyperglycemia induced tubular injuries.MethodsForty non-diabetic SD rats were randomly divided and treated with different concentrations of hyperglycemia respectively during the 6-h clamp experiment. Renal morphological and functional alterations were detected. Rat renal tubular epithelial cells were treated with different concentrations of glucose for 6 h. Markers and the regulation pathway of mitophagy were analyzed.ResultsSignificant tubular injuries but not glomeruli were observed under both light and electron microscope after acute hyperglycemia treatment, which manifested as enlargement of tubular epithelial cells, disarrangement of epithelial cell labyrinths and swelling of mitochondria. Urinary microalbumin, β2-MG, CysC, NAG, GAL, and NGAL were increased significantly with the increase of blood glucose (P < 0.05). ROS was activated, mitochondrial membrane potential and LC3-II/LC3-I ratio were decreased but P62 and BNIP3L/Nix were increased in hyperglycemia groups (P < 0.05), which were reversed by AMPK activation or mTOR inhibition.ConclusionAcute hyperglycemia causes obvious tubular morphological and functional injuries in a dose-dependent manner. Acute hyperglycemia could inhibit mitophagy through AMPK/mTOR pathway, which would aggravate mitochondria damage and renal tubular impairment.

High ACR level is a strong risk factor for renal tubular impairment in patients with type 2 diabetes: A longitudinal observational study

BackgroundSeveral studies have indicated that high albuminuria is associated with renal function decline. However, the relationship between the urinary albumin-to-creatinine ratio (ACR) and risk of developing tubular injury remains unclear. Our aim was to investigate the association of ACR with the risk of developing tubular impairment in patients with type 2 diabetes. MethodsThis longitudinal observational study compared baseline with follow-up data in 183 patients with type 2 diabetes. ACR, urinary alpha-1-microglobulin-to-creatinine ratio (A1MCR) and estimated glomerular filtration rate (eGFR) were used to evaluate albuminuira, tubular injury and glomerular filtration function, respectively. ResultsLevels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and A1MCR were significantly different at the two-year follow-up compared with baseline levels. Among patients both with baseline ACR above and below 30 mg/g, the percentage with A1MCR > 15 mg/g clearly increased after follow-up (P < 0.05). The risk of A1MCR rising from normal ranges to >15 mg/g over the follow-up increased with increasing baseline ACR values lower baseline eGFR. Among the patients with baseline ACR > 63.10 mg/g, all showed increased A1MCR values at follow-up compared with baseline. In the multivariate regression analysis, the patients with baseline ACR > 63.10 mg/g had a strong risk of A1MCR rising from normal to >15 mg/g (odds ratio (OR) = 11.12, P = 0.001) over the follow-up, while the males had a 2.89-fold risk of A1MCR increasing from normal to >15 mg/g compared with females. ConclusionBaseline ACR level is related to increased risk of developing renal tubular injury; in particular, this association is much stronger in patients with type 2 diabetes and baseline ACR > 63.10 mg/g.

Calcaneal Quantitative Ultrasonography and Urinary Retinol-Binding Protein in Antiretroviral-Treated Patients With Human Immunodeficiency Virus in Uganda: A Pilot Study.

Data on bone health and renal impairment in people with human immunodeficiency virus (HIV) in resource-limited settings are limited. The primary aim of this study was to investigate the potential role of calcaneal quantitative ultrasonography (QUS) in predicting bone mineral density (BMD) reduction in a population of Ugandan HIV-infected individuals receiving long-term antiretroviral therapy; the secondary end point was to assess the prevalence of proximal tubular dysfunction and the correlation between elevated urinary retinol-binding protein-urinary creatinine ratio (uRBP/uCr) and reduced BMD. We conducted a cross-sectional study at the Infectious Diseases Institute, Kampala, Uganda. We included 101 HIV-infected adults who had been receiving continuous antiretroviral therapy for ≥10 years and had undergone dual-energy x-ray absorptiometry (DXA) during the previous 12 months. All patients underwent calcaneal QUS evaluation and urine sample collection. DXA BMD measurements were significantly associated (P < .01) with calcaneal speed of sound, broadband ultrasound attenuation, and QUS index. Forty-seven individuals (47%) had abnormal uRBP/uCr values. A significant inverse correlation was observed between uRBP/uCr and DXA T scores (lumbar [P = .03], femoral neck [P < .001], and total hip [P = .002]). Calcaneal QUS results showed a moderate correlation with DXA outputs. The identified high prevalence of subclinical tubular impairment also highlights the importance of expanding access to tenofovir disoproxil fumarate-sparing regimens in resource-limited settings.

C/EBP\u03b1 deficiency in podocytes aggravates podocyte senescence and kidney injury in aging mice

Kidney aging leads to an increased incidence of end-stage renal disease (ESRD) in the elderly, and aging is a complex biological process controlled by signaling pathways and transcription factors. Podocyte senescence plays a central role in injury resulting from kidney aging. Here, we demonstrated the critical role of C/EBPα in podocyte senescence and kidney aging by generating a genetically modified mouse model of chronological aging in which C/EBPα was selectively deleted in podocytes and by overexpressing C/EBPα in cultured podocytes, in which premature senescence was induced by treatment with adriamycin. Moreover, we illuminated the mechanisms by which podocyte senescence causes tubular impairment by stimulating HK-2 cells with bovine serum albumin (BSA) and chloroquine. Our findings suggest that C/EBPα knockout in podocytes aggravates podocyte senescence through the AMPK/mTOR pathway, leading to glomerulosclerosis, and that subsequent albuminuria exacerbates the epithelial–mesenchymal transdifferentiation of senescent tubular cells by suppressing autophagy. These observations highlight the importance of C/EBPα as a new potential target in kidney aging.

Clinical significance of detection of urine renal injury biomarkers in children with primary nephrotic syndrome

Objective To investigate the clinical significance of detection of urine renal injury biomarkers in children with primary nephrotic syndrome (PNS). Methods Seventy-nine children with PNS at the Department of Nephrology, Tianjin Children′s Hospital were enrolled from January to December 2016, who were given sufficient glucocorticoid for 4 weeks.According to the response to glucocorticoid, they were divided into steroid-sensitive nephrotic syndrome (SSNS) group (63 cases) and steroid-resistant nephrotic syndrome (SRNS) group (16 cases), then they were divided into simple type and nephritic type according to diagnostic criteria.Urinary levels of microalbuminuria (MAlb), transferrin (TfR), retinal binding protein (RBP), N-acetyl-β-D-glucosaminidase (NAG), α1-microglobulin (α1-MG) and β2-microglobulin (β2-MG) were measured in the children before and after treatment, and the data were analyzed by the statistical method. Results Before treatment, the levels of RBP, NAG, α1-MG and β2-MG in the SSNS group [0.91(1.80) mg/L, 28.00(31.5) U/L, 8.40(14.2) mg/L, 0.45(0.35) mg/L]were lower than those in SRNS group[3.94(4.82) mg/L, 37.10(18.20) U/L, 11.10(21.42) mg/L, 0.66(1.41) mg/L], and the differences were statistically significant (all P<0.05); After treatment, the MAlb, TfR, RBP, NAG, α1-MG, β2-MG in the SSNS group [14.10(5.60) mg/L, 0.40(1.60) mg/L, 0.26(0.38) mg/L, 7.90(9.10) U/L, 2.00(4.40) mg/L, 0.27(0.35) mg/L] were lower than those before treatment[MAlb: 1 704.00(1 995.60) mg/L, TfR: 142.10(81.90) mg/L] and those after treatment in the SRNS group[557.90(1 857.17) mg/L, 117.40(102.10) mg/L, 4.19(5.15) mg/L, 38.80(32.43) U/L, 10.85(16.60) mg/L, 0.63(0.91) mg/L], and the differences were statistically significant (all P<0.05). However, before and after treatment, except for MAlb[before treatment: 2 258.75(2 028.43) mg/L], the indicators in the SRNS group were not significantly improved.Before treatment, the RBP in the SRNS group was significantly higher than that in the SSNS group in children with simple type PNS, and the RBP, NAG, α1-MG and β2-MG in the SRNS group were significantly higher than those in the SSNS group in children with nephritic type PNS (all P<0.05). According to receiver operating characteristic curve, there were obvious differences in the urinary levels of RBP, NAG and β2-MG, and area under curve(AUC) was 0.858, 0.837 and 0.679, respectively, all of which were <0.9, so the value of diagnosis was not high.Logistic regression analysis was used to identify RBP and NAG as influencing factors and to establish a model.Through the combined detection of these two indicators, the diagnostic value was higher (AUC was 0.956), and when the diagnostic sensitivity was 93.8%, the specificity could reach 82.5%. Conclusions Urinary RBP, NAG, α1-MG and β2-MG can early reflect tubular interstitial impairment in children with PNS, especially SRNS.Combined detection of RBP and NAG has certain value in predicting the efficacy of glucocorticoid. Key words: Primary nephrotic syndrome; Microalbuminuria; Transferrin; Retinal binding protein; N-acetyl-β-D-glucosaminidase; α1-microglobulin; β2-microglobulin

A New Estimate of the Glomerular Sieving Coefficient for Retinol-Binding Protein 4 Suggests It Is Not Freely Filtered

A New Estimate of the Glomerular Sieving Coefficient for Retinol-Binding Protein 4 Suggests It Is Not Freely Filtered

Renal Consequences of Gestational Diabetes Mellitus in Term Neonates: A Multidisciplinary Approach to the DOHaD Perspective in the Prevention and Early Recognition of Neonates of GDM Mothers at Risk of Hypertension and Chronic Renal Diseases in Later Life

Fetal exposure to gestational diabetes mellitus (GDM) seems to stimulate a negative impact on the kidneys. Renal volumes and urinary biomarkers of renal function and tubular impairment and injury were evaluated in 30–40-day old newborns of GDM mothers (n = 139) who needed insulin therapy during pregnancy. We found that neonates of mothers who maintained strict control over normoglycemia (n = 65) during pregnancy and fulfilled the other criteria of the GDM management program showed no differences compared to control (n = 55). Conversely, those (n = 74), whose mothers did not maintain glycemic control and were not compliant to the management program, exhibited significantly lower levels of renal volumes and higher activity of N-acetyl-β-d-glucosaminidase and cathepsin B. Differences due to maternal pre-gestational and gestational body mass index (BMI) as well as to maternal weight gain were demonstrated. Our findings indicate that a multidisciplinary approach, which involves an appropriate management of GDM, prevents the negative effects of GDM on the kidneys at 30–40 days of postnatal age, indicating the fundamental role of glycemic control, as well as of an adequate range of maternal weight gain. Total renal volume, cortical volume, and urinary activity of N-acetyl-β-d-glucosaminidase and cathepsin B may be suggested as indicators for the early recognition of GDM neonates at long-term risk of hypertension and kidney disease.

Chronic exposure to low-level cadmium induced zinc-copper dysregulation

Background and objectivesExposure to cadmium (Cd) has been associated with aberrant zinc and copper homeostasis. This study investigated if Cd exposure impairs renal reabsorption of metals. MethodsRenal tubular reabsorption of metals were calculated from urine to serum metal ratios and analyzed for an independent association with Cd exposure levels, using data from 100 men and 100 women, aged 16–60 years. ResultsThe smoking prevalence was 30% in men and 0% in women. The male and female means (SD) for urine Cd were 0.54 (0.43) and 0.62 (0.43) μg/g creatinine. The mean (SD) for fractional zinc reabsorption was 77.2 (23) % in men and 87.7 (13.3) % in women, while the copper reabsorption was 100% in both men and women. Lower zinc reabsorption levels were associated with higher Cd exposure (P<0.001), higher serum copper to zinc ratios (P=0.007) and higher tubular impairment levels (P=0.024). Reduced zinc reabsorption was particularly severe in smokers as those with high Cd exposure had 44.9% and 37.2% (P<0.001) lower zinc reabsorption than those with low and moderate exposures. The mean zinc reabsorption in male non-smokers with high Cd exposure was 25.8% (P<0.001) and 18.2% (P=0.003) lower than those with low and moderate exposures, while the corresponding figure for female non-smokers was 17% (P<0.001), and 12.8% (P=0.013), respectively. ConclusionsThis is the first report demonstrating Cd-dose dependent reduction in renal zinc reabsorption and high serum copper to zinc ratios.

O38-4 - Changes of urinary Liver-type Fatty Acid Binding during Therapeutic Course of Acute Decompensated Heart Failure

Introduction: Urinary Liver-type Fatty Acid Binding Protein (uL-FABP) is known as a marker reflecting renal tubular impairment in worsening renal function (WRF). However, its clinical significance has not been elucidated in patients with acute decompensated heart failure (ADHF), especially changes of uL-FABP is little known. Methods and Results: This prospective, observational study included 208 patients (mean age: 77 year, 51% male) presenting with ADHF. uL-FABP and other biomarkers were measured at admission and before discharge. WRF was defined as a rise in serum creatinine >0.3 mg/dl within seven days from admission. Median uL-FABP/Cr levels significantly decreased from 7.8 to 2.9 µg/gCr (P < .0001). These changes of uL-FABP were correlated with changes of aspartate aminotransferase (r = 0.27, P < .0001) and alanine aminotransferase (r = 0.24, P < .0001), although they were not correlated with changes of brain natriuretic peptide and estimated glomerular filtration rate. uL-FABP/Cr levels at admission were associated with WRF in the univariate logistic regression analysis (P = .03), but changes of uL-FABP/Cr were not associated. Conclusion: In patients with ADHF, uL-FABP decreased significantly during treatment. The decrease was correlated with changes of liver enzyme, though it was not associated with WRF.

Dynamic renal scintigraphic estimation of deceased donor kidneys in a rat model.

At present a large number of the renal transplantations are being performed from the deceased donors. The success of these transplantations depends on the viability of the deceased donor kidneys. The aim of this study was to investigate the reliability of scintigraphic estimation of function of deceased donor kidneys by comparing the histopathologic and scintigraphic findings. Ten rats were included in the study (2-3 months old, 250-300 g, all male). Control scintigraphy was performed to all the rats by injection of 37 MBq Tc-99m DTPA from the tail vein in a dynamic manner. Brain death of the rats was achieved by inflation of a Fogartys catheter in the cranial cavity. Immediately, after brain death confirmation, dynamic renal scintigraphy was performed with the same parameters of control scintigraphy. In the comparison of scintigraphies obtained in the before and just after brain death period, there was impairment of tubular functions, concentration and excretion functions in the postbrain death period. In the immediate postbrain death period, there was a significant elevation in the glomerular filtration rate and time to maximum concentration values. In the histopathological evaluation of the kidney samples in the postbrain death period, there were definitive findings of tubular impairment. Dynamic renal scintigraphy also demonstrated definite impairment of tubular system and tubular functions in the deceased donor kidneys. This could explain the reason of the increased frequency of acute tubular necrosis seen among deceased donor kidneys.

Tenofovir clearance is reduced in HIV-positive patients with subclinical tubular impairment.

To assess if tenofovir (TFV) clearance is associated with urinary retinal-binding protein (RBP) in HIV-positive patients with normal estimated filtration rate. A cross-sectional diagnostic study. HIV-positive patients with estimated creatinine clearance above 60 ml/min, on tenofovir disoproxil fumarate (TDF)-containing combination since at least 6 months, taking TDF at night, and without significant comorbidities (diabetes, untreated hypertension, known renal malformations, recurrent nephrolithiasis) and nephrotoxic drugs were included. TFV plasma and urinary concentrations were measured 12 h after drug intake (C12). RBP was measured through enzyme immunoassay kit on spot urines and corrected per urinary creatinine (uRBP/uCr); normality ranges were below 130 μg/g (in patients aged <50 years) and below 172 μg/g (in patients aged ≥50 years). Two hundred and eighty-nine patients were included (median age of 45.8 years, 71.6% male and 85.4% whites); patients were concomitantly treated with nonnucleoside reverse transcriptase inhibitors (155, 53.6%), protease inhibitors (118, 40.8%), or integrase inhibitors (16, 5.5%)-containing regimens. Estimated creatinine clearance was 89.4 ml/min (78.6-105.9). Urinary RBP (uRBP) and uRBP/uCr were 204.6 ng/ml (92-380) and 169.7 μg/g (85.8-318.3), respectively; abnormally high uRBP/uCr was observed in 157 patients (54.3%). A multivariate binary logistic regression confirmed that both ethnicity (P = 0.004, β 2.93, 95% confidence interval 1.41-6.10) and TFV urinary C12 less than 21 mg/ml (P = 0.006, β 2.04, 95% confidence interval 1.12-3.41) were significantly associated with abnormal uRBP/uCr. HIV-positive TDF-treated patients showed a high prevalence of proximal tubular impairment: ethnicity (whites) and low urinary TFV concentrations were significantly associated with elevated uRBP. SDC VIDEO:: http://links.lww.com/QAD/A852.

Associations of Low Environmental Exposure to Multiple Metals with Renal Tubular Impairment in Korean Adults.

Recently several studies reported that the renal toxicity of lead (Pb) and cadmium (Cd) may exist in even a low level exposure. In terms of the deterioration of tubular function, it affects the loss of divalent metals and leads to other complications, so renal tubular effect of heavy metals should be well managed. Considering the exposure to heavy metals in reality, it is hard to find the case that human is exposed to only one heavy metal. We designed a cross-sectional study using Korean Research Project on the Integrated Exposure Assessment (KRIEFS) data to investigate the renal effects of multiple metal exposure in general population. We used blood Pb and urinary Cd as exposure measures, and urinary N-acetyl-β-D-glucosaminidase (NAG) and β2-microglobulin (β2-MG) as renal tubular impairment outcome. We conducted linear regression to identify the association between each heavy metal and urinary NAG and β2-MG. And then, we conducted linear regression including the interaction term. Of 1953 adults in KRIEFS (2010~2011), the geometric mean of blood Pb and urinary Cd concentration was 2.21 μg/dL (geometric SD = 1.49 μg/dL) and 1.08 μg/g cr (geometric SD = 1.98 μg/g cr), respectively. In urinary Cd, the strength of the association was also high after adjusting (urinary NAG: β = 0.44, p < 0.001; urinary β2-MG: β = 0.13, p = 0.002). Finally, we identified the positive interactions for the two renal biomarkers. The interaction effect of the two heavy metals of β2-MG was greater than that of NAG. It is very important in public health perspective if the low level exposure to multiple heavy metals has an interaction effect on kidney. More epidemiological studies for the interaction and toxicological studies on the mechanism are needed.