Selenium-binding protein 1: a sensitive urinary biomarker to detect heavy metal-induced nephrotoxicity

Identifying novel biomarkers to detect nephrotoxicity is clinically important. Here, we attempted to identify new biomarkers for mercury-induced nephrotoxicity and compared their sensitivity to that of traditional biomarkers in animal models. Comparative proteomics analysis was performed in kidney tissues of Sprague-Dawley rats after oral treatment with HgCl₂ (0.1, 1, or 5 mg/kg/day) for 21 days. Kidney cortex tissues were analyzed by two-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization, and differentially expressed proteins were identified. The corresponding spots were quantitated by RT-PCR. Selenium-binding protein 1 (SBP1) was found to be the most markedly upregulated protein in the kidney cortex of rats after HgCl₂ administration. However, blood urea nitrogen, serum creatinine, and glucose levels increased significantly only in the 1 or 5 mg/kg HgCl₂-treated groups. A number of urinary excretion proteins, including kidney injury molecule-1, clusterin, monocyte chemoattractant protein-1, and β-microglobulin, increased dose-dependently. Histopathological examination revealed severe proximal tubular damage in high-dose (5 mg/kg) HgCl₂-exposed groups. In addition, urinary excretion of SBP1 significantly increased in a dose-dependent manner. To confirm the critical role of SBP1 as a biomarker for nephrotoxicity, normal kidney proximal tubular cells were treated with HgCl₂, CdCl₂, or cisplatin for 24 h. SBP1 levels significantly increased in conditioned media exposed to nephrotoxicants, but decreased in cell lysates. Our investigations suggest that SBP1 may play a critical role in the pathological processes underlying chemical-induced nephrotoxicity. Thus, urinary excretion of SBP1 might be a sensitive and specific biomarker to detect early stages of kidney injury.

Rapid enlargement of endometrial stromal sarcoma after uterine fibroid embolization for presumed adenomyosis: a case report and literature review

Uterine sarcomas have rarely been diagnosed after uterine artery embolization. It remains unclear whether the diagnostic work-up is required prior to such embolization to prevent a missed diagnosis of sarcomas and a delay in providing definitive treatment. Because of the rarity and heterogeneity of endometrial stromal neoplasms, little is known about their epidemiology, pathogenesis, and molecular pathology. The authors report a case of low-grade endometrial stromal sarcoma (ESS) diagnosed after uterine fibroid embolization. Although they performed laparoscopic biopsy of the rapidly growing uterine mass, they could not detect the ESS. Although rare, ESS should be considered in the differential diagnosis of uterine fibroid enlargement. It is essential to assess the risk of malignancy by taking into account the patient's clinical symptoms, results of the physical exam, and imaging findings prior to uterine artery embolization. Pathologic diagnosis should include an adequate biopsy sample and the use of molecular genetic testing.

Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Switching dynamics of ferroelectric materials are governed by the response of domain walls to applied electric field. In epitaxial ferroelectric films, thermally-activated ‘creep’ motion plays a significant role in domain wall dynamics, and accordingly, detailed understanding of the system’s switching properties requires that this creep motion be taken into account. Despite this importance, few studies have investigated creep motion in ferroelectric films under ac-driven force. Here, we explore ac hysteretic dynamics in epitaxial BiFeO₃ thin films, through ferroelectric hysteresis measurements, and stroboscopic piezoresponse force microscopy. We reveal that identically-fabricated BiFeO₃ films on SrRuO₃ or La_0.67Sr_0.33MnO₃ bottom electrodes exhibit markedly different switching behaviour, with BiFeO₃/SrRuO₃ presenting essentially creep-free dynamics. This unprecedented result arises from the distinctive spatial inhomogeneities of the internal fields, these being influenced by the bottom electrode’s surface morphology. Our findings further highlight the importance of controlling interface and defect characteristics, to engineer ferroelectric devices with optimised performance.

Abstract W P261: Increased Susceptibility of Blood-Brain Barrier to Ischemic Damage by a Diabetic Metabolite Methylglyoxal

Ischemic stroke is the major cause of death or disability in diabetic patients. Diabetic patients have higher incidence of stroke, however the underlying molecular mechanisms are not clear. The blood level of methylglyoxal (MG), a byproduct of glycolysis, is significantly increased in patients with diabetes. Several studies have reported that MG might play a key role in vascular dysfunction under diabetic condition. In this study, we investigated if MG disrupts blood-brain barrier (BBB) function and increases the susceptibility of BBB to ischemic damage. Treatment of MG significantly decreased cell viability of bEND.3 cells, an in vitro BBB model. MG increased the permeability in bEND.3 in a dose-dependent manner. In addition, the level of occludin, a tight junction protein, was decreased after exposure to MG. To investigate the change in susceptibility to ischemic damage under high concentration of MG, we exposed bEnd.3 cells to MG for 12 hours prior to oxygen-glucose deprivation (OGD). Cell viability assay revealed an increased ischemic cell death under high level of MG, indicating that MG increased susceptibility to ischemic damage of BBB. Taken together, we demonstrated ischemic disruption of BBB can be enhanced by exposure to MG, suggesting that MG-induced BBB disruption might be a key factor in the susceptible ischemic damage under diabetic condition.

Erythrophagocytosis of lead-exposed erythrocytes by renal tubular cells: possible role in lead-induced nephrotoxicity

BACKGROUND

Nephrotoxicity associated with lead poisoning has been frequently reported in epidemiological studies, but the underlying mechanisms have not been fully described.

OBJECTIVES

We examined the role of erythrocytes, one of the major lead reservoirs, in lead-associated nephrotoxicity.

METHODS AND RESULTS

Co-incubation of lead-exposed human erythrocytes with HK-2 human renal proximal tubular cells resulted in renal tubular cytotoxicity, suggesting a role of erythrocytes in lead-induced nephrotoxicity. Morphological and flow cytometric analyses revealed that HK-2 cells actively phagocytized lead-exposed erythrocytes, which was associated with phosphatidylserine (PS) externalization on the erythrocyte membrane and generation of PS-bearing microvesicles. Increased oxidative stress and up-regulation of nephrotoxic biomarkers, such as NGAL, were observed in HK-2 cells undergoing erythrophagocytosis. Moreover, TGF-β, a marker of fibrosis, was also significantly up-regulated. We examined the significance of erythrophagocytosis in lead-induced nephrotoxicity in rats exposed to lead via drinking water for 12 weeks. We observed iron deposition and generation of oxidative stress in renal tissues of lead-exposed rats, as well as the histopathological alterations such as tubulointerstitial lesions, fibrosis, and up-regulation of KIM-1, NGAL, and TGF-β.

CONCLUSIONS

Our data strongly suggest that erythrophagocytosis and subsequent iron deposition in renal tubular cells could significantly enhance nephrotoxicity following lead exposure, providing insight on lead-associated kidney damages.

Abstract T P250: Role of Autophagy in Blood-Brain Barrier Disruption and Tight Junction Degradation Under Ischemic Condition

During ischemic stroke, the integrity of blood-brain barrier (BBB), which shows selective permeability for substances to brain, is significantly damaged amplifying ischemic neuronal damage. There have been attempts to identify the exact mechanism ischemic BBB disruption to minimize brain damage under ischemic stroke. Autophagy is catabolic process which involves degradation and recycling of damaged or unnecessary organelles. However, excessive autophagy can induce cell damage and death under pathological conditions such as ischemia. In this study, we evaluated if autophagy is a key mechanism of BBB dysfunction under ischemic stroke. In vitro BBB model of bEnd.3 cells were exposed to oxygen-glucose deprivation (OGD), an ischemic mimic condition. After exposure to OGD for 18 hours, cell viability was significantly decreased and cellular permeability was impaired. The conversion of LC3-I to LC3-II and puncta of LC3 in bEnd.3 were increased, demonstrating that autophagy is induced under ischemic condition. Modulation of autophagy by 3-methyladenine, an autophagy inhibitor, reversed the conversion of LC3 as well as decreased cell viability, suggesting that autophagy involves in ischemic BBB damage. The level of occludin, a tight junction protein in BBB, was decreased after OGD, and this was reversed by inhibition of autophagy. Our findings showed that induction of autophagy might contribute to increased permeability through occludin degradation in brain endothelial cells under ischemia, providing a new mechanism of BBB disruption in ischemic stroke.

Protective activity of Dendropanax morbifera against cisplatin-induced acute kidney injury

BACKGROUND/AIMS

Drug-induced acute kidney injury (AKI) has been a severe threat to hospitalized patients, raising the urgent needs to develop strategies to reduce AKI. We investigated the protective activity of Dendropanax morbifera (DP), a medicinal plant which has been widely used to treat infectious and pain diseases, on acute kidney injury (AKI) using cisplatin-induced nephropathic models.

METHODS

Both in vitro renal tubular cells (NRK-52E) and in vivo rat models were used to demonstrate the nephroprotective effect of DP.

RESULTS

Methanolic extract from DP significantly reduced cisplatin-induced toxicity in renal tubular cells. Through successive liquid extraction, the extract of DP was separated into n-hexane, CHCl3, EtOAc, n-BuOH, and H2O fractions. Among these, the CHCl3 fraction (DPCF) was found to be most potent. The protective activity of DPCF was found to be mediated through anti-oxidant, mitochondrial protective, and anti-apoptotic activities. In in vivo rat models of AKI, treatment with DPCF significantly reversed the cisplatin-induced increase in blood urea nitrogen and serum creatinine and histopathologic damage, recovered the level of anti-oxidant enzymes, and inhibited renal apoptosis.

CONCLUSION

We demonstrated that DP extracts decreased cisplatin-induced renal toxicity, indicating its potential to ameliorate drug-associated acute kidney damage.

Modulation of mitochondrial function and autophagy mediates carnosine neuroprotection against ischemic brain damage

BACKGROUND AND PURPOSE

Despite the rapidly increasing global burden of ischemic stroke, no therapeutic options for neuroprotection against stroke currently exist. Recent studies have shown that autophagy plays a key role in ischemic neuronal death, and treatments that target autophagy may represent a novel strategy in neuroprotection. We investigated whether autophagy is regulated by carnosine, an endogenous pleiotropic dipeptide that has robust neuroprotective activity against ischemic brain damage.

METHODS

We examined the effect of carnosine on mitochondrial dysfunction and autophagic processes in rat focal ischemia and in neuronal cultures.

RESULTS

Autophagic pathways such as reduction of phosphorylated mammalian target of rapamycin (mTOR)/p70S6K and the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II were enhanced in the ischemic brain. However, treatment with carnosine significantly attenuated autophagic signaling in the ischemic brain, with improvement of brain mitochondrial function and mitophagy signaling. The protective effect of carnosine against autophagy was also confirmed in primary cortical neurons.

CONCLUSIONS

Taken together, our data suggest that the neuroprotective effect of carnosine is at least partially mediated by mitochondrial protection and attenuation of deleterious autophagic processes. Our findings shed new light on the mechanistic pathways that this exciting neuroprotective agent influences.

Silymarin-loaded solid nanoparticles provide excellent hepatic protection: physicochemical characterization and in vivo evaluation

Background

The purpose of this study was to develop a novel silymarin-loaded solid nanoparticle system with enhanced oral bioavailability and an ability to provide excellent hepatic protection for poorly water-soluble drugs using Shirasu porous glass (SPG) membrane emulsification and a spray-drying technique.

Methods

A silymarin-loaded liquid nanoemulsion was formulated by applying the SPG membrane emulsification technique. This was further converted into solid state nanosized particles by the spray-drying technique. The physicochemical characteristics of these nanoparticles were determined by scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. Their dissolution, bioavailability, and hepatoprotective activity in rats were assessed by comparison with a commercially available silymarin-loaded product.

Results

Formulation of a silymarin-loaded nanoemulsion, comprising silymarin, castor oil, polyvinylpyrrolidone, Transcutol HP, Tween 80, and water at a weight ratio of 5/3/3/1.25/1.25/100 was accomplished using an SPG membrane emulsification technique at an agitator speed of 700 rpm, a feed pressure of 15 kPa, and a continuous phase temperature of 25°C. This resulted in generation of comparatively uniform emulsion globules with a narrow size distribution. Moreover, the silymarin-loaded solid nanoparticles, containing silymarin/castor oil/polyvinylpyrrolidone/Transcutol HP/Tween 80 at a weight ratio of 5/3/3/1.25/1.25, improved about 1,300-fold drug solubility and retained a mean size of about 210 nm. Silymarin was located in unaltered crystalline form in the nanoparticles. The drug dissolved rapidly from the nanoparticles, reaching nearly 80% within 15 minutes, indicating three-fold better dissolution than that of the commercial product. Further, the nanoparticles showed a considerably shorter time to peak concentration, a greater area under the concentration-time curve, and a higher maximum concentration of silymarin compared with the commercial product (P < 0.05). In particular, the area under the concentration-time curve of the drug provided by the nanoparticles was approximately 1.3-fold greater than that of the commercial product. In addition, the silymarin-loaded nanoparticles significantly reduced carbon tetrachloride-induced hepatotoxicity, indicating improved bioactivity compared with silymarin powder and the commercial product.

Conclusion

Silymarin-loaded nanoparticles developed using SPG membrane emulsification and spray-drying techniques could be a useful system for delivery of poorly water-soluble silymarin while affording excellent hepatic protection.

Comprehensive clinical follow-up of late effects in childhood cancer survivors shows the need for early and well-timed intervention

BACKGROUND

Due to recent advances in treatment, nearly 80% of childhood cancer patients become long-term survivors. Studies on the late effects of survivors are under way worldwide. However, data on Asian survivors remain limited.

METHODS

Data on 241 survivors at the Long-term Follow-up Clinic in Severance Hospital, South Korea, were collected and late effects were confirmed by oncologists.

RESULTS

The median follow-up from diagnosis was 7.8 years. Late effects were identified in 59.8% of survivors and 23.2% had two or more late effects. Grade 3 or higher late effects were present in 10.8%. The most common late effects involved endocrine system (29.0%). Late effects were present in 95.7% of brain tumor survivors and 36.0% of Wilms' tumor survivors. Chemotherapy, hematopoietic stem-cell transplantation and radiotherapy were significant factors associated with the number and severity of late effects (P < 0.05). Brain tumor survivors had more severe late effects (P < 0.001), whereas Wilms' tumor survivors had fewer and milder late effects (P < 0.05).

CONCLUSION

The observation that over 50% of cancer survivors suffered from late effects during the short follow-up period and that a high frequency of endocrine late effects was present indicates the need for early and well-timed intervention of the survivors.

Circulating osteoprotegerin levels are elevated and correlated with antiphospholipid antibodies in patients with systemic lupus erythematosus

Patients with antiphospholipid syndrome (APS) have an increased risk for the development of thrombotic complications. Recent studies indicate that osteoprotegerin (OPG) acts as an important molecule in the development of vascular diseases. The aim of the present study was to examine the association between serum OPG levels and APS manifestations in patients with SLE. Seventy-nine patients with SLE and ninety-two healthy controls, matched for age and sex, were included in this study. Serum levels of OPG, monocyte chemoattractant protein(MCP)-1 and soluble E-selectin were determined by ELISA. At the time of serum sampling, various clinical and laboratory parameters were assessed. We found that serum levels of OPG were significantly higher in patients with SLE than in healthy controls (1236 ± 82 vs 967 ± 37 pg/mL, P = 0.003). Particularly, serum OPG levels were significantly higher in SLE patients with APS than those without (1615 ± 191 vs 1171 ± 91 pg/mL, P = 0.006). Serum OPG levels correlated with titres of IgG anti-cardiolipin antibody ( P = 0.026) and anti-β2-glycoprotein I antibody ( P < 0.001). Moreover, serum OPG also correlated with serum levels of sE-selectin ( P = 0.002), which is an endothelial cell activation marker, and MCP-1 ( P = 0.003), a well known chemokine implicated in thrombogenesis. Collectively, serum OPG levels were increased in SLE patients with APS and correlated with titres of antiphospholipid antibodies, suggesting that OPG might be linked to the development of APS.

3-(1H-tetrazol-5-yl)-1,4,5,6-tetrahydro-cyclopentapyrazole (MK-0354): a partial agonist of the nicotinic acid receptor, G-protein coupled receptor 109a, with antilipolytic but no vasodilatory activity in mice

The discovery and profiling of 3-(1H-tetrazol-5-yl)-1,4,5,6-tetrahydro-cyclopentapyrazole (5a, MK-0354), a partial agonist of GPR109a, is described. Compound 5a retained the plasma free fatty acid lowering effects in mice associated with GPR109a agonism, but did not induce vasodilation at the maximum feasible dose. Moreover, preadministration of 5a blocked the flushing effect induced by nicotinic acid but not that induced by PGD2. This profile made 5a a suitable candidate for further study for the treatment of dyslipidemia.

Fabrication of transparent capacitive structure by self-assembled thin films

An approach to fabricating transparent electronic devices by using nanomaterial and nanofabrication is presented in this paper. A see-through capacitor is constructed from self-assembled silica nanoparticle layers that are stacked on the transparent substrate. The electrodes are made of indium tin oxide. Unlike the traditional processes used to fabricate such devices, the self-assembly approach enables one to synthesize the thin film layers at lower temperature and cost, and with a broader availability of nanomaterials. The vertical dimension of the self-assembled thin films can be precisely controlled, as well as the molecular order in the thin film layers. The shape of the capacitor is generated by planar micropatterning. The monitoring by quartz crystal demonstrates the steady growth of the silica nanoparticle multilayer. In addition, because the material synthesis and the device fabrication steps are separate, the fabrication is not affected by the harsh conditions required for the material synthesis. As a result, a clear pattern is allowed over a large area on the substrate. The prepared capacitive structure has an optical transparency higher than 92% over the visible spectrum. The capacitive impedance is measured at different frequencies and fit the theoretical results. As one of the fundamental components, this type of capacitive structure can serve in the transparent circuits, interactive media and sensors, as well as being applicable to other transparent devices.

Fluorinated pyrazole acids are agonists of the high affinity niacin receptor GPR109a

A series of 5-alkyl pyrazole-3-carboxylic acids were prepared and found to act as potent and selective agonists of the human GPCR, GPR109a, the high affinity nicotinic acid receptor. No activity was observed at the highly homologous low affinity niacin receptor, GPR109b. A further series of 4-fluoro-5-alkyl pyrazole-3-carboxylic acids were shown to display similar potency. One example from the series was shown to have improved properties in vivo compared to niacin.

Agonist lead identification for the high affinity niacin receptor GPR109a

A strategy for lead identification of new agonists of GPR109a, starting from known compounds shown to activate the receptor, is described. Early compound triage led to the formulation of a binding hypothesis and eventually to our focus on a series of pyrazole acid derivatives. Further elaboration of these compounds provided a series of 5,5-fused pyrazoles to be used as lead compounds for further optimization.

Relationship between the change in overweight status from childhood to adolescence and metabolic syndrome phenotypes: a 9-year retrospective study

OBJECTIVE

To evaluate how the changes in overweight status from childhood to adolescence are related to metabolic syndrome phenotypes in adolescents.

SUBJECTS AND METHODS

A total 375 adolescents aged 16 years. The overweight status from childhood to adolescence (from 7 years of age to 16 years) was determined by body mass index (BMI, kg/m(2)) calculated from records of the School Physical Examination data. The change in body weight was classified into four groups: normal weight to normal weight (NW-NW); overweight to normal (OW-NW); normal to overweight (NW-OW); overweight to overweight (OW-OW). Metabolic syndrome phenotypes were examined from a cross-sectional survey.

RESULTS

The mean values of all phenotypes except for body fatness (BMI and waist) and the cluster score of phenotypes at 16 years of age were not different between the NW-NW group and the OW-NW group, nor between the NW-OW group and the OW-OW group. However, the score as well as the level of body fatness and blood glucose were significantly different between current overweight and normal adolescents regardless of overweight status during childhood (P<0.05).

CONCLUSION

There was a linear relationship between overweight status during childhood and metabolic syndrome phenotypes in adolescence but current overweight status (adolescence overweight) was more closely related to the adolescent risk of metabolic syndrome than childhood overweight status.

Clusterin induces differentiation of pancreatic duct cells into insulin-secreting cells

AIMS/HYPOTHESIS

We recently reported that expression of the gene encoding clusterin (Clu) is upregulated in the regenerating pancreas, particularly in tissues undergoing differentiation. This led us to propose that clusterin participates in the cytodifferentiation of pancreatic tissue, particularly the endocrine islet cells. The aim of this study was to investigate whether clusterin induces the differentiation of duct-lining cells into insulin-secreting cells.

METHODS

We isolated ductal tissue from rat pancreas and cultured it to develop epithelial cell explants for transfection of the Clu cDNA as well as for treatment of clusterin protein.

RESULTS

The number of newly differentiated insulin cells increased 6.9-fold upon Clu overexpression compared with controls. Ins1 mRNA and peptide levels were also increased. Furthermore, glucose-stimulated insulin secretion was observed in the differentiated insulin cells. These cells were immunoreactive for insulin and C-peptide, but negative for other islet hormones and for cytokeratin-20, which indicates a fully differentiated state. Insulin cell differentiation was also increased in a dose-dependent manner by treating duct cells in culture with clusterin, indicating a growth-factor-like action of clusterin in insulin cell differentiation.

CONCLUSIONS/INTERPRETATION

These results suggest that clusterin can be considered as a potential morphogenic factor that promotes differentiation of pancreatic beta cells.