Association and mediation analyses among multiple metals exposure, plasma folate, and community-based impaired estimated glomerular filtration rate in central Taiwan.

BACKGROUND: Chronic kidney disease (CKD) is increasing, with heavy metal exposure an important risk factor. Additionally, the antioxidant folic acid has been studied for reducing blood arsenic levels and related tissue damage. Therefore, we explored the association and mediation effects among various heavy metal levels in blood, plasma folate, other CKD risk factors, and impaired estimated glomerular filtration rate (eGFR). METHODS: We constructed a community-based cross-sectional study from the Human Biomonitoring and Environmental Health Program in central Taiwan. A total of 1643 participants had lived locally for > 5 years, > 40 years old, and completely received health examinations and biospecimen collections. Impaired eGFR was defined as one single eGFR < 60 mL/min/1.73 m2. Plasma folate and metal levels in blood were determined, as well as urinary 8-hydroxy-2'-deoxyguanosine as an oxidative stress marker. Generalized weighted quantile sum (WQS) regression analysis was used to calculate a WQS score, reflecting overall body-burden of multiple metals (arsenic, cadmium, chromium, nickel, and lead) in blood. RESULTS: Impaired eGFR was identified in 225 participants. Participants with high WQS scores had increased risk of impaired eGFR (odds ratio = 1.67; 95% confidence interval [CI]: 1.34, 2.07). Of five metals, arsenic, lead, and cadmium were weighted highly in impaired eGFR. Participants with high WQS and folate insufficiency (< 6 ng/mL) had 2.38-fold risk of impaired eGFR compared to those with low WQS and high folate (≥6 ng/mL) (95% CI: 1.55, 5.17). Similar increased 4.16-fold risk of impaired eGFR was shown in participants with high WQS and uric acid levels (95% CI: 2.63, 6.58). However, there were no significant WQS-folate (p = 0.87) or WQS-uric acid (p = 0.38) interactions on impaired eGFR risk. As a mediator, uric acid contributed 24% of the association between WQS score and impaired eGFR risk (p < 0.0001). However, no mediation effect of plasma folate was observed. CONCLUSION: WQS analysis could be applied to evaluate the joint effects of multiple metals exposure. High WQS scores may influence impaired eGFR risk through increased uric acid levels. A large-scale and prospective cohort study is necessary to validate these results and demonstrate any causal relationship.

Development of MRI-Detectable Boron-Containing Gold Nanoparticle-Encapsulated Biodegradable Polymeric Matrix for Boron Neutron Capture Therapy (BNCT).

This study aimed to develop a novel magnetic resonance imaging (MRI)-detectable boron (B)-containing nanoassemblies and evaluate their potential for boron neutron capture therapy (BNCT). Starting from the citrate-coated gold nanoparticles (AuNPs) (23.9 ± 10.2 nm), the diameter of poly (D, L-lactide-co-glycolide) AuNPs (PLGA-AuNPs) increased approximately 110 nm after the encapsulation of the PLGA polymer. Among various B drugs, the self-produced B cages had the highest loading efficiency. The average diameter of gadolinium (Gd)- and B-loaded NPs (PLGA-Gd/B-AuNPs) was 160.6 ± 50.6 nm with a B encapsulation efficiency of 28.7 ± 2.3%. In vitro MR images showed that the signal intensity of PLGA-Gd/B-AuNPs in T1-weighted images was proportional to its Gd concentration, and there exists a significantly positive relationship between Gd and B concentrations (R2 = 0.74, p < 0.005). The hyperintensity of either 250 ± 50 mm3 (larger) or 100 ± 50 mm3 (smaller) N87 xenograft was clearly visualized at 1 h after intravenous injection of PLGA-Gd/B-AuNPs. However, PLGA-Gd/B-AuNPs stayed at the periphery of the larger xenograft while located near the center of the smaller one. The tumor-to-muscle ratios of B content, determined by inductively coupled plasma mass spectrometry, in smaller- and larger-sized tumors were 4.17 ± 1.42 and 1.99 ± 0.55, respectively. In summary, we successfully developed theranostic B- and Gd-containing AuNPs for BNCT in this study.

Molybdenum induces pancreatic ß-cell dysfunction and apoptosis via interdependent of JNK and AMPK activation-regulated mitochondria-dependent and ER stress-triggered pathways.

Molybdenum (Mo), a well-known toxic environmental and industrial pollutant, causes adverse health effects and diseases in humans and has received attention as a potential risk factor for DM. However, the roles of Mo in the mechanisms of the toxicological effects in pancreatic ß-cells are mostly unclear. In this study, the results revealed dysfunction of insulin secretion and apoptosis in the pancreatic ß-cell-derived RIN-m5F cells and the isolated mouse islets in response to Mo. These effects were accompanied by a mitochondria-dependent apoptotic signals including a decreased in the MMP, an increase in cytochrome c release, and the activation of caspase cascades and PARP. In addition, ER stress was triggered as indicated by several key molecules of the UPR. Furthermore, exposure to Mo induced the activation of ERK1/2, JNK, AMPKα, and GSK3-α/ß. Pretreatment with specific pharmacological inhibitors (in RIN-m5F cells and isolated mouse islets) of JNK (SP600125) and AMPK (Compound C) or transfection with si-RNAs (in RIN-m5F cells) specific to JNK and AMPKα effectively prevented the Mo-induced apoptosis and related signals, but inhibitors of ERK1/2 and GSK3-α/ß (PD98059 and LiCl, respectively) did not reverse the Mo-induced effects. Additionally, both the inhibitors and specific si-RNAs could suppress the Mo-induced phosphorylation of JNK and AMPKα each other. Taken together, these results suggest that Mo exerts its cytotoxicity on pancreatic ß-cells by inducing dysfunction and apoptosis via interdependent JNK and AMPK activation downstream-regulated mitochondrial-dependent and ER stress-triggered apoptosis pathways.

Differential accumulation of trace elements in ventral and dorsal muscle tissues in tilapia and milkfish with different feeding habits from the same cultured fishery pond.

There were many studies that reported the concentrations of trace elements in fish and assessed the human health risk through consumption of contaminated fish. However, fish species with different feeding habits may accumulate toxic elements differentially in their muscle. In this study, we conducted a field survey to analyze concentrations of ten trace elements in water, sediment, artificial feed, and different part of muscles either with or without skin of two species of fish, tilapia and milkfish. The results of this study showed that the ventral and dorsal muscles with skin contained higher concentrations of metals than those without skin for both species of fish. Tilapia lives in the bottom layer, the ventral part therefore contacts closely with sediment. A higher metal concentration in ventral muscle was obtained in this study when compared to dorsal muscle for tilapia. The estimated Metal Pollution Index (MPI) of tilapia is higher than that of milkfish. Our results indicated that metal concentrations in muscle of tilapia are mainly originated from sediment. However, sources of metal concentrations in muscle of milkfish can be from sediment and artificial feed.

Oxidative DNA damage estimated by urinary 8-hydroxy-2'-deoxyguanosine and arsenic in glass production workers.

A total of 130 male glass workers, including 33 administrative workers, 18 batch house workers, 42 craftsmen, and 37 melting process workers, were recruited to investigate the potential DNA damage resulting from toxic element exposure. The occupational exposure to trace elements, including arsenic (As), cadmium (Cd), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se), was estimated by their urinary levels as internal doses. In addition, all participants filled a self-filled questionnaire indicating their individual information. The average levels of urinary As, Cd, Mn, Ni, Pb, Se, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were 282.3 ± 464.6, 3.07 ± 5.39, 3.81 ± 11.43, 81.48 ± 138.9, 18.23 ± 49.61, 165.2 ± 224.9, and 17.21 ± 26.34 µg/g creatinine, respectively. The urinary levels of 8-OHdG and toxic elements were strongly associated with the work nature of the worker, with an exception of Mn and Pb. In contrast, the levels of toxic element were not influenced by age, smoking behavior, and alcohol consumption. The urinary 8-OHdG was found significantly higher in higher internal exposure groups of As, Cd, Ni, and Se. However, the stepwise multiple regression models showed that urinary 8-OHdG was only associated with urinary As and heat stress but inversely with age.

Quercetin induces tongue squamous cell carcinoma cell apoptosis via the JNK activation-regulated ERK/GSK-3α/ß-mediated mitochondria-dependent apoptotic signaling pathway.

Tongue squamous cell carcinoma (SCC) is a most common type of oral cancer. Due to its highly invasive nature and poor survival rate, the development of effective pharmacological therapeutic agents is urgently required. Quercetin (3,3',4',5,7-pentahydroxyflavone) is a polyphenolic flavonoid found in plants and is an active component of Chinese herbal medicine. The present study investigated the pharmacological effects and possible mechanisms of quercetin on apoptosis of the tongue SCC-derived SAS cell line. Following treatment with quercetin, cell viability was assessed via the MTT assay. Apoptotic and necrotic cells, mitochondrial transmembrane potential and caspase-3/7 activity were analyzed via flow cytometric analyses. A caspase-3 activity assay kit was used to detect the expression of caspase-3 activity. Western blot analysis was performed to examine the expression levels of proteins associated with the MAPKs, AMPKα, GSK3-α/ß and caspase-related signaling pathways. The results revealed that quercetin induced morphological alterations and decreased the viability of SAS cells. Quercetin also increased apoptosis-related Annexin V-FITC fluorescence and caspase-3 activity, and induced mitochondria-dependent apoptotic signals, including a decrease in mitochondrial transmembrane potential and Bcl-2 protein expression, and an increase in cytosolic cytochrome c, Bax, Bak, cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase protein expression. Furthermore, quercetin significantly increased the protein expression levels of phosphorylated (p)-ERK, p-JNK1/2 and p-GSK3-α/ß, but not p-p38 or p-AMPKα in SAS cells. Pretreatment with the pharmacological JNK inhibitor SP600125 effectively reduced the quercetin-induced apoptosis-related signals, as well as p-ERK1/2 and p-GSK3-α/ß protein expression. Both ERK1/2 and GSK3-α/ß inhibitors, PD98059 and LiCl, respectively, could significantly prevent the quercetin-induced phosphorylation of ERK1/2 and GSK3-α/ß, but not JNK activation. Taken together, these results suggested that quercetin may induce tongue SCC cell apoptosis via the JNK-activation-regulated ERK1/2 and GSK3-α/ß-mediated mitochondria-dependent apoptotic signaling pathway.

Mutation analysis and characterization of alternative splice variants of the Wilson disease gene ATP7B.

UNLABELLED: Wilson disease is a copper metabolism disorder caused by mutations in ATP7B, a copper-transporting adenosine triphosphatase. A molecular diagnosis was performed on 135 patients with Wilson disease in Taiwan. We identified 36 different mutations, eight of which were novel: five missense mutations (Ser986Phe, Ile1348Asn, Gly1355Asp, Met1392Lys, and Ala1445Pro), one deletion (2810delT) in the coding region, and two nucleotide substitutions (-133A→C and -215A→T) in the promoter region. These mutations were not observed in 100 control subjects and reduced the activity of the mutated protein by at least 50% when compared with wild-type ATP7B. In addition to exon 8, our data indicate another mutation hotspot in exon 12 where 9.62% of all mutations occurred. An alternative splice variant of ATP7B lacking exon 12 was observed in one patient who had a homozygous 2810delT mutation and very mild clinical symptoms. Clinical examination and functional characterization of alternative splice variants of ATP7B lacking exon 12 showed that they retained 80% of their biological activity. The 2810delT mutation increased the expression of these variants, which may have explained the mild symptoms in the patient with the 2810delT mutation. We also discovered that treating liver cancer cells with a Na(+)/H(+) exchanger inhibitor, 5-(N-ethyl-N-isopropyl)-amiloride, significantly enhanced the expression of the alternative splice variant of ATP7B lacking exon 12. CONCLUSION: This study suggests a novel therapeutic strategy for patients with mutations in exon 12.

Inorganic arsenic causes cell apoptosis in mouse cerebrum through an oxidative stress-regulated signaling pathway.

Arsenic pollution is a major public health problem worldwide. Inorganic arsenic (iAs) is usually more harmful than organic ones. iAs pollution increases the risk of human diseases such as peripheral vascular disease and cancer. However, the toxicological effects of iAs in the brain are mostly unclear. Here, we investigated the toxic effects and possible mechanisms of iAs in the cerebrum of mice after exposure to iAs (0.5 and 5 ppm (mg/l) As(2)O(3), via the drinking water), which was the possible human exposed dose via the ingestion in iAs-contaminated areas, for 6 consecutive weeks. iAs dose-dependently caused an increase of LPO production in the plasma and cerebral cortex. iAs also decreased the reduced glutathione levels and the expressions of NQO1 and GPx mRNA in the cerebral cortex. These impairments in the cerebral cortex caused by iAs exposure were significantly correlated with the accumulation of As. Moreover, iAs induced the production of apoptotic cells and activation of caspase-3, up-regulation of Bax and Bak, and down-regulation of Mcl-1 in the cerebral cortex. Exposure to iAs also triggered the expression of ER stress-related genes, including GRP78, GRP94, and CHOP. Meanwhile, an increase of p38 activation and dephosphorylation of ERK1/2 were shown in the cerebral cortex as a result of iAs-exposed mice. These iAs-induced damages and apoptosis-related signals could be significantly reversed by NAC. Taken together, these results suggest that iAs-induced oxidative stress causes cellular apoptosis in the cerebrum, signaling of p38 and ERK1/2, and ER stress may be involved in iAs-induced cerebral toxicity.

Water outage increases the risk of gastroenteritis and eyes and skin diseases.

BACKGROUND: The present study used insurance claims data to investigate infections associated with short-term water outage because of constructions or pipe breaks. METHODS: The present study used medical claims of one million insured persons for 2004-2006. We estimated incidences of gastroenteritis and eye and skin complaints for 10 days before, during, and after 10 days of water supply restriction for outpatient visits and for emergency and in-patient care combined. RESULTS: There was an increase in medical services for these complaints in outpatient visits because of water outages. Poisson regression analyses showed that increased risks of medical services were significant for gastroenteritis (relative risk [RR] 1.31, 95% confidence interval [CI] 1.26-1.37), skin disease (RR 1.36, 95% CI 1.30-1.42), and eye disease patients (RR 1.34, 95% CI 1.26-1.44). Similar risks were observed during 10-day lag periods. Compared with those in cool days, risks of medical services are higher when average daily temperature is above 30 °C for gastroenteritis (RR 12.1, 95% CI 6.17-23.7), skin diseases (RR 4.48, 95% CI 2.29-8.78), and eye diseases (RR 40.3, 95% CI 7.23-224). CONCLUSION: We suggest promoting personal hygiene education during water supply shortages, particularly during the warm months.

Lead poisoning due to incense burning: an outbreak in a family.

BACKGROUND: In Asia and some other regions of the world, incense burning is an important folk and cultural activity. However, this ritual can cause health impacts, such as chronic respiratory diseases and neoplasms. Herein, we describe a family with lead poisoning possibly related to the frequent use of incense sticks at home. CASE REPORT: A 65-year-old homemaker with severe anemia, pitting edema of the lower legs, bone pain, abdominal pain, and exertional dyspnea for several months presented to our clinic. Her blood workup indicated severe anemia with basophilic stippling in red blood cells and blood lead level (BLL) of 59.75 µg/dL. Her husband, three children, and four grandchildren who lived with her also had high BLLs. As a Daoist clergy person, she had been exposed to a large amount of smoke from every day use of incense for >30 years. In the field investigation, the chronic dust deposited in hidden corners of their home had considerably higher lead content and other toxic metals. DISCUSSION: Our observations indicated chronic, frequent exposure to smoke from incense burning may be a cause of lead poisoning. Strict avoidance of incense smoke is a significant step toward preventing lead poisoning in children in societies with the custom of incense burning.

Arsenic induces autophagy-dependent apoptosis via Akt inactivation and AMPK activation signaling pathways leading to neuronal cell death.

Inorganic arsenic (As3+), a well-known worldwide industrial and environmental pollutant, has been linked to neurodegenerative disorders (NDs). Autophagy plays an important role in controlling neuronal cell survival/death. However, limited information is available regarding the toxicological mechanism at the interplay between autophagy and As3+-induced neurotoxicity. The present study found that As3+ exposure induced a concomitant activation of apoptosis and autophagy in Neuro-2a cells, which was accompanied with the increase of phosphatidylserine exposure on outer membrane leaflets and apoptotic cell population, and the activation of caspase-3, -7, and PARP as well as the elevation of protein expressions of LC3-II, Atg-5, and Beclin-1, and the accumulation of autophagosome. Pretreatment of cells with autophagy inhibitor 3-MA, but not that of Z-VAD-FMK (a pan-caspase inhibitor), effectively prevented the As3+-induced autophagic and apoptotic responses, indicating that As3+-triggered autophagy was contributing to neuronal cell apoptosis. Furthermore, As3+ exposure evoked the dephosphorylation of Akt. Pretreatment with SC79, an Akt activator, could significantly attenuated As3+-induced Akt inactivation as well as autophagic and apoptotic events. Expectedly, inhibition of Akt signaling with LY294002 obviously enhanced As3+-triggered autophagy and apoptosis. Exposure to As3+ also dramatically increased the phosphorylation level of AMPKα. Pretreatment of AMPK inhibitor (Compound C) could markedly abrogate the As3+-induced phosphorylated AMPKα expression, and autophagy and apoptosis activation. Taken together, these results indicated that As3+ exerted its cytotoxicity in neuronal cells via the Akt inactivation/AMPK activation downstream-regulated autophagy-dependent apoptosis pathways, which ultimately lead to cell death. Our findings suggest that the regulation of Akt/AMPK signals may be a promising intervention to against As3+-induced neurotoxicity and NDs.

Adherence to Nutritional Supplementation Determines Postoperative Vitamin D Status, but Not Levels of Bone Resorption Marker, in Sleeve-Gastrectomy Patients.

BACKGROUND: Taking advantage of isomeric form of vitamin E in the supplement, adherence to supplement could be evaluated by changes in circulating α- and γ-tocopherol concentrations. Accordingly, effects of supplementation on postoperative nutrition and bone metabolism were studied in terms of adherence. METHODS: Thirty-eight SG patients were all prescribed a postoperative nutritional supplement containing a low dose of vitamin D (600 IU) and calcium (200 mg). Blood samples were collected prior to (M0) and 6 months after (M6) surgery and concentrations of nutrients and C-terminal telopeptide of type I collage (CTX), a marker of bone resorption, were measured. Adherence and non-adherence were stratified according to change (△, M6-M0) in serum α-tocopherol concentrations (> 0 vs. ≤ 0, respectively). RESULTS: When M0 and M6 were compared, there were significant increases in serum concentrations of 25(OH)D, α-tocopherol and selenium, whereas there were reductions in parathyroid hormone, ferritin, and γ-tocopherol. At M6, the prevalence of vitamin D insufficiency (25(OH)D < 30 ng/mL) and high CTX were 72 and 26%, respectively. When comparison was made between adherence and non-adherence, only △25(OH)D concentrations, but no other nutrients nor postoperative CTX differed. Multiple linear regression demonstrated that postoperative vitamin D status was independently associated with its preoperative concentrations (ß = 0.85, p < 0.001) and adherence (ß = 0.52, p < 0.05). CONCLUSION: SG patients' adherence to supplementation, even with a low dose of vitamin D and calcium, determined vitamin D status but not bone resorption marker concentrations, at least within 6 months after surgery.

Roles of ERK/Akt signals in mitochondria-dependent and endoplasmic reticulum stress-triggered neuronal cell apoptosis induced by 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene, a major active metabolite of bisphenol A.

Bisphenol A (BPA) is recognized as a harmful pollutant in the worldwide. Growing studies have reported that BPA can cause adverse effects and diseases in human, and link to a potential risk factor for development of neurodegenerative diseases (NDs). 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), which generated in the mammalian liver after BPA exposure, is a major active metabolite of BPA. MBP has been suggested to exert greater toxicity than BPA. However, the molecular mechanism of MBP on the neuronal cytotoxicity remains unclear. In this study, MBP exposure significantly reduced Neuro-2a cell viability and induced apoptotic events that MBP (5-15 µM) exhibited greater neuronal cytotoxicity than BPA (50-100 µM). The mitochondria-dependent apoptotic signals including the decrease in mitochondrial membrane potential (MMP) and the increase in cytosolic apoptosis-induced factor (AIF), cytochrome c release, and Bax protein expression were involved in MBP (10 µM)-induced Neuro-2a cell death. Exposure of Neuro-2a cells to MBP (10 µM) also triggered endoplasmic reticulum (ER) stress through the induction of several key molecules including glucose-regulated protein (GRP)78, C/EBP homologous protein (CHOP), X-box binding protein (XBP)-1, protein kinase R-like ER kinase (PERK), eukaryotic initiation factor 2α (eIF2α), inositol-requiring enzyme(IRE)-1, activation transcription factor(AFT)4 and ATF6, and caspase-12. Pretreatment with 4-PBA (an ER stress inhibitor) and specific siRNAs for GRP78, CHOP, and XBP-1 significantly suppressed the expression of these ER stress-related proteins and the activation of caspase-12/-3/-7 in MBP-exposed Neuro-2a cells. Furthermore, MBP (10 µM) exposure dramatically increased the activation of extracellular regulated protein (ERK)1/2 and decreased Akt phosphorylation. Pretreatment with PD98059 (an ERK1/2 inhibitor) and transfection with the overexpression of activation of Akt1 (myr-Akt1) effectively suppressed MBP-induced apoptotic and ER stress-related signals. Collectively, these results demonstrate that MBP exposure exerts neuronal cytotoxicity via the interplay of ERK activation and Akt inactivation-regulated mitochondria-dependent and ER stress-triggered apoptotic pathway, which ultimately leads to neuronal cell death.

Effects of ambient PM2.5 and particle-bound metals on the healthy residents living near an electric arc furnace: A community- based study.

Fine particulate matter (PM2.5) emitted from electric arc furnaces (EAFs) poses health concerns. However, little research has been done on the impact of EAF on the health of community residents. This cross-sectional study conducted a PM2.5 exposure assessment and health examination of community residents living near an EAF. A total of 965 residents aged 40-90 years were recruited. The residents' exposure to PM2.5 was categorized according to the distance of their residence from the EAFs (<500, 500-1000, 1000-1500, 1500-2000, and > 2000 m). Average ambient PM2.5 concentrations were estimated using a hybrid kriging/land-use regression (LUR) model. In addition, we selected two air-sampling sites to monitor the 2-year levels of PM2.5 and particle-bound metals. A spot urine sample and blood samples were collected and ten heavy metal concentrations in the blood were analyzed. Inflammation- and oxidative stress-related biomarkers were measured. The associations between environmental factors and a biochemical examination were estimated using a generalized linear model. Active air sampling and hybrid kriging/LUR model simulation indicated increased levels of PM2.5 near the EAF. The metal concentrations in PM2.5 included Fe, Pb, Mn, Ni, As, Cu, Ni, Zn, and Al, which also significantly increased near the EAF. PM2.5 levels were significantly associated with an increased total cholesterol-high-density lipoprotein (TC/HDL) ratio. High levels of PM2.5 and malondialdehyde were associated with a 1.72-fold increased risk of TC/HDL ratio ≥ 4 (95% CI: 1.12-2.65) after adjusting for potential confounding factors. Blood Pb levels were significantly associated with increased systolic and diastolic blood pressure and decreased estimated glomerular filtration rate but negatively associated with distance from the EAF. The results show that people living near EAFs should pay more attention to adverse health problems, including atherogenic dyslipidemia, hypertension, and chronic kidney disease associated with exposure to PM2.5 and particle-bound metals.

Ultrafine silicon dioxide nanoparticles cause lung epithelial cells apoptosis via oxidative stress-activated PI3K/Akt-mediated mitochondria- and endoplasmic reticulum stress-dependent signaling pathways.

Silicon dioxide nanoparticles (SiO2NPs) are widely applied in industry, chemical, and cosmetics. SiO2NPs is known to induce pulmonary toxicity. In this study, we investigated the molecular mechanisms of SiO2NPs on pulmonary toxicity using a lung alveolar epithelial cell (L2) model. SiO2NPs, which primary particle size was 12 nm, caused the accumulation of intracellular Si, the decrease in cell viability, and the decrease in mRNAs expression of surfactant, including surfactant protein (SP)-A, SP-B, SP-C, and SP-D. SiO2NPs induced the L2 cell apoptosis. The increases in annexin V fluorescence, caspase-3 activity, and protein expression of cleaved-poly (ADP-ribose) polymerase (PARP), cleaved-caspase-9, and cleaved-caspase-7 were observed. The SiO2NPs induced caspase-3 activity was reversed by pretreatment of caspase-3 inhibitor Z-DEVD-FMK. SiO2NPs exposure increased reactive oxygen species (ROS) production, decreased mitochondrial transmembrane potential, and decreased protein and mRNA expression of Bcl-2 in L2 cells. SiO2NPs increased protein expression of cytosolic cytochrome c and Bax, and mRNAs expression of Bid, Bak, and Bax. SiO2NPs could induce the endoplasmic reticulum (ER) stress-related signals, including the increase in CHOP, XBP-1, and phospho-eIF2α protein expressions, and the decrease in pro-caspase-12 protein expression. SiO2NPs increased phosphoinositide 3-kinase (PI3K) activity and AKT phosphorylation. Both ROS inhibitor N-acetyl-l-cysteine (NAC) and PI3K inhibitor LY294002 reversed SiO2NPs-induced signals described above. However, the LY294002 could not inhibit SiO2NPs-induced ROS generation. These findings demonstrated first time that SiO2NPs induced L2 cell apoptosis through ROS-regulated PI3K/AKT signaling and its downstream mitochondria- and ER stress-dependent signaling pathways.

Ecosystem metabolism regulates seasonal bioaccumulation of metals in atyid shrimp (Neocaridina denticulata) in a tropical brackish wetland.

Natural dissolved organic matter (DOM) forms the base of aquatic food webs and is a key environmental factor that affects the bioavailability of metals for aquatic organisms. Aquatic communities are naturally exposed simultaneously to environments containing a mixture of metals and varying DOM levels and compositions. However, the exact effect of DOM on metal bioaccumulation is difficult to predict due to temporal and spatial variations in sources, production, and consumption of DOM, and to interactions between DOM and metals. Ecosystem metabolism describes the process of organic carbon production and consumption and, therefore, the trophic status of ecosystems. However, whether and how ecosystem metabolism determines the seasonality of metal bioaccumulation remains unclear. The present study used in-situ water quality sondes and discrete field samplings to establish the relationship between the seasonality of ecosystem metabolism; related environmental and limnological regulators; the metal speciation and concentration in bulk water and sediments; and their metal bioaccumulation. The target population consisted of atyid shrimp (Neocaridina denticulata) in a brackish constructed wetland in tropical Taiwan was sampled between August 2014 and November 2015. Metal bioaccumulation displayed distinct seasonal patterns that peaked in summer (Cu, Cd, Cr, Zn, Mn, and Se) or winter (Pb and Ni). The in situ production (gross primary production) and heterotrophic consumption (ecosystem respiration) of organic matter significantly decreased with increasing waterborne DOM levels in this heterotrophic wetland. Both dissolved free metals bioavailable for respiratory surfaces (As, Zn, Cu, and Cr) and insoluble metals available for dietary intake (Mn and Ni) decreased with increasing DOM, as well as with decreasing gross primary production and ecosystem respiration. Seasonal variations of metal bioaccumulation also paralleled the transition in wetland trophic status, which reflected the effect of potential qualitative changes in the wetland DOM pool. Bioaccumulation of most metals displayed strong correlations with gross primary production, ecosystem respiration, and wetland trophic status. Our findings demonstrated that ecosystem metabolism can play a key mediating role in the seasonality of metal bioaccumulation in atyid shrimp, as it links the variation and interaction between DOM level/source, the speciation/bioavailability, and the uptake efficiency for metals by aquatic organisms. This study contributes to the temporal-specific risk assessment of aquatic metal exposure in regional environmental settings. It also reveals ecosystem-specific spectra in the context of changes in climate and environment.

Silica nanoparticles induce caspase-dependent apoptosis through reactive oxygen species-activated endoplasmic reticulum stress pathway in neuronal cells.

Human exposure to silica nanoparticles (SiNPs) has been widely applied as vehicles for drug delivery and cellular manipulations in nanoneuromedicine. SiNPs may cause adverse effects in the brain, but potential mechanisms underlying SiNPs-induced neurotoxicity are remained unclear. Here, we examined cytotoxic effects and the cellular mechanisms of SiNPs-induced neuronal cell death. In this study, the results showed that SiNPs significantly decreased cell viability and induced apoptosis in Neuro-2a cells as evidenced by the increase caspase-3 activity and the activation of caspase cascades and poly (ADP-ribose) polymerase (PARP). In addition, endoplasmic reticulum (ER) stress was triggered as indicated by several key molecules including glucose-regulated protein (GRP)78 and 94, C/EBP homologous protein (CHOP), activation transcription factor (ATF)-4, and caspase-12. Pretreatment of Neuro-2a cells with specific pharmacological inhibitor of ER stress (4-phenylbutyric acid (4-PBA)) effectively alleviated the SiNPs-induced ER stress and apoptotic related signals. Furthermore, 2',7'-Dichlorofluorescein fluorescence as an indicator of reactive oxygen species (ROS) formation after exposure of Neuro-2a cells to SiNPs significantly increased ROS levels. Antioxidant N-acetylcyseine (NAC) effectively reversed SiNPs-induced cellular responses. Taken together, these results suggest that SiNPs exposure exerts its neurotoxicity in cultured neuronal cells by inducing apoptosis via a ROS generation-activated downstream ER stress signaling pathway.

Nutritional Status of Obese Taiwanese Before Bariatric-Metabolic Surgery and Their Serum 25-Hydroxyvitamin D Concentrations for Maximal Suppression of Parathyroid Hormone.

BACKGROUND: This is the first report from Taiwan using laboratory tests to assess nutritional status of patients with obesity before bariatric-metabolic surgery. Moreover, the 25(OH)D threshold for maximal suppression of parathyroid hormone (PTH) was evaluated to offer a reference value for preoperative nutritional care. METHODS: Inclusion criteria were Taiwanese, 18-65 years old, and with BMI ≥ 27.5 kg/m2 awaiting bariatric-metabolic surgery. Anthropometric data and blood samples were collected before surgery. Serum concentrations of protein; vitamins B1, B12, folate, A, D, and E; calcium; iron; zinc; copper; selenium; PTH; and erythrocyte glutathione reductase activity coefficient (vitamin B2 status) were measured. RESULTS: For 52 participants with a mean BMI 37.6 ± 6.4 kg/m2, vitamin D deficiency (25(OH)D < 20 ng/mL) and insufficiency (20 < 25(OH)D < 30 ng/mL) were at 73 and 22% prevalence, respectively. Secondary hyperparathyroidism (PTH â‰§ 65 pg/mL) was 24% and hypocalcemia was 50% (ionized Ca < 4.5 mg/dL). Deficiency of other nutrients was sporadic (< 10%) or nil. When participants were stratified according to 25(OH)D concentrations (< 10, 10-15, 15-20, and ≥ 20 ng/mL), PTH increased at 25(OH)D < 10 ng/mL (ß = 48.34, p = 0.001) after adjusting for age, gender, and BMI. CONCLUSION: For patients with obesity before bariatric-metabolic surgery, vitamin D/calcium deficiency was the only nutritional issue that needs to be addressed in Taiwan. However, a lower cutoff point of 25(OH)D, i.e., 10 ng/mL, for vitamin D deficiency may be considered for patients before surgery. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03915158.

Health risk of consuming heavy metals in farmed tilapia in central Taiwan.

Taiwan is a small island nation, and many aquaculture sites are located near industrial parks. Anthropogenic activities may contaminate fish ponds. Therefore, we investigated the concentrations of eight metal elements in tilapia tissues (muscle and scale) at two fisheries. We compared the difference in metal content in tilapia at these two fisheries with that in non-contaminated fish at the Fisheries Research Institute. Probabilistic risk analysis was carried out to assess the health risk for people who eat contaminated tilapia. The predicted 95th percentiles of the hazard quotient and excess lifetime cancer risk for residents consuming contaminated tilapia were found to be in the range of 3.1-9.2 and 1.03 x 10(-5)-1.85 x 10(-5), respectively.

Methylmercury exposure induces ROS/Akt inactivation-triggered endoplasmic reticulum stress-regulated neuronal cell apoptosis.

Epidemiological studies have positively linked mercury exposure and neurodegenerative diseases (ND). Methylmercury (MeHg), an organic form of mercury, is a ubiquitous and potent environmental neurotoxicant that easily crosses the blood-brain barrier and causes irreversible injury to the central nervous system (CNS). However, the molecular mechanisms underlying MeHg-induced neurotoxicity remain unclear. Here, the present study found that Neuro-2a cells underwent apoptosis in response to MeHg (1-5 µM), which was accompanied by increased phosphatidylserine (PS) exposure on the outer cellular membrane leaflets, caspase-3 activity, and the activation of caspase cascades and poly (ADP-ribose) polymerase (PARP). Exposure of Neuro-2a cells to MeHg also triggered endoplasmic reticulum (ER) stress, which was identified via several key molecules (including: glucose-regulated protein (GRP)78, GRP94, C/EBP homologous protein (CHOP) X-box binding protein(XBP)-1, protein kinase R-like ER kinase (PERK), eukaryotic initiation factor 2α (eIF2α), inositol-requiring enzyme(IRE)-1, activation transcription factor(AFT)4, and ATF6. Transfection with GRP78-, GRP94-, CHOP-, and XBP-1-specific small interfering (si)RNA significantly suppressed the expression of these proteins, and attenuated cytotoxicity and caspase-12, -7, and -3 activation in MeHg-exposed cells. Furthermore, MeHg dramatically decreased Akt phosphorylation, and the overexpression of activation of Akt1 (myr-Akt1) could significantly prevent MeHg-induced Akt inactivation, as well as apoptotic and ER stress-related signals. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively prevented MeHg-induced neuronal cell reactive oxygen species (ROS) generation, apoptotic and ER stress-related signals, and Akt inactivation. Collectively, these results indicate that MeHg exerts its cytotoxicity in neurons by inducing ROS-mediated Akt inactivation up-regulated ER stress, which induces apoptosis and ultimately leads to cell death.