Corbicula fluminea gene expression modulated by CeO2 nanomaterials and salinity.

Cerium dioxide nanomaterials (CeO2 NMs) are used in different fields and incorporated in daily products. Several studies highlighted their effects on organism physiology, although molecular studies remain scarce. NM behavior is strongly dependent on the environment but few data are available using complex exposure media, raising the question of its environmental impacts. The aim of the present work was to assess the toxic potential of three CeO2 NMs in Corbicula fluminea at a molecular level by RT-qPCR under a more realistic scenario of exposure, in a multistress context at two different salinities (1.5 and 15 psu). C. fluminea was exposed for 28 days to pulses of the three selected NMs (reference, manufactured, and aged manufactured). In bivalves, the gills and digestive gland are two key organs used for ecotoxicological studies. The expression change of 12 genes was measured in control organisms after 28 days in both organs, allowing us to clearly separate the responses for both organs and salinities. As gills come in contact with the environment first, we monitored gene the expression at intermediate time points (7, 14, and 21 days) for this organ in order to highlight clams responses to NM and salinity. Two genes (Se-GPx, MnSOD) had a salinity-dependent level of expression. HSP70, Se-GPx, and Trxr mRNAs presented significant changes in their expressions in the presence of NM. This study was completed using an integrated statistical approach. The exposed organisms differed more from control at field salinity than those exposed to hyper-saline conditions. At 15 psu, salinity pressure seems to cause the first molecular impact. At 1.5 psu, gene expression patterns allowed the effect of each NM to separate clearly. These results confirmed the usefulness of gene expression studies. Moreover, we highlighted the necessity to assess the environmental toxicity of the different forms of manufactured NM.

Genotoxicity and physiological effects of CeO2 NPs on a freshwater bivalve (Corbicula fluminea).

The rapid development of nanotechnology and the increased use of nanomaterials in products used in everyday life have raised the question of the potential release of nanoparticles into the aquatic environment. Their fate and effects in natural ecosystems are not currently well understood but harmful effects of nanoparticles have been demonstrated at low concentrations on some freshwater and marine species. Cerium dioxide nanoparticles (CeO2 NPs) are produced in large quantities and used in products in many different fields, such as automotives or optics. Because of their widespread use in daily products, CeO2 NPs are included in the OECD priority list of manufactured nanomaterials for human and environmental assessment. Indeed some studies have been conducted to assay various enzymatic biomarkers, which showed the CeO2 NPs potential to modify anti-oxidative defenses and cellular membrane stability. Nevertheless, only a few studies were performed on their genotoxic potential. The aim of this work was to evaluate the genotoxic and physiological effects of CeO2 NPs on a widespread freshwater bivalve Corbicula fluminea by using comet assay and a multi-enzymatic biomarker approach. Exposure to two CeO2 NP concentrations during a short term experiment (6 days) was set up. The first one (10 µg/L) was chosen in order to work with low but measurable concentrations whereas the second one was ten times higher (100 µg CeO2 NPs/L). DNA damage was significantly more pronounced compared with control for both concentrations tested as early as two days of exposure and seemed to increase with time. Some enzymatic biomarkers of anti-oxidative defenses (total antioxidant capacity, catalase activity), anti-toxic mechanisms (glutathione-S-transferase activity, caspase-3 activity) or metabolism (lactate dehydrogenase activity) tended to increase after 6 days of exposure but only the induction of caspase pathway and DNA damages appeared significant for exposed organisms. In this study, time and concentration effects of CeO2 NPs were highlighted by coupling genotoxic and cellular biomarker assessments.

Differential tolerance to nickel between Dreissena polymorpha and Dreissena rostriformis bugensis populations.

Differential tolerance to stress is partly responsible for the heterogeneity of biomarker responses between populations of a sentinel species. Although currently used for freshwater biomonitoring, studies concerning inter-populational variability in tolerance to contaminants for the zebra mussel (Dreissena polymorpha) are scarce. Moreover, this well-known invader is currently replaced by another, the quagga mussel (Dreissena rostriformis bugensis). To evaluate the differential tolerance between dreissenids, several populations of both species were exposed to a high concentration of nickel. A LT50 (time when 50% of individuals were dead) was established for each population. Biomarker responses and internal nickel concentration were also measured, to link tolerance with physiological status. Results evidenced that D. polymorpha populations are more heterogeneous and more tolerant than D. r. bugensis ones. For D. polymorpha populations only, LT50 values were positively correlated with the nickel contamination in situ, with higher anti-oxidative defences and a higher Integrated Biomarker Response value in the field. Such findings may be explained by local adaptation and invasion dynamic within each species. The significance of this differential tolerance when using biomarker responses for biomonitoring purposes is thus discussed.

The influence of salinity on the fate and behavior of silver standardized nanomaterial and toxicity effects in the estuarine bivalve Scrobicularia plana.

Because of their antibacterial properties, silver (Ag) engineered nanomaterials are included in many products. The present study used a standardized Ag nanomaterial (NM-300K, 20 nm) supplied with a stabilizing agent. The aim was to investigate the behavior of Ag nanomaterial in an estuarine-like medium at 2 salinities (15 psu and 30 psu). Uptake as well as sublethal effects of Ag nanomaterial (10 µg Ag/L), its stabilizing agent, and AgNO3 (10 µg Ag/L) were assessed in the clam Scrobicularia plana, after 7 d of exposure. The release of soluble Ag from Ag nanomaterial in the experimental media was quantified by using diffusive gradient in thin films and ultrafiltration. A multibiomarker approach was employed to reveal responses of clams at subindividual and individual levels. The bioaccumulation of Ag was significantly greater at 15 psu versus 30 psu, which could be explained by differences in Ag speciation. In conclusion, the present study showed different impacts of Ag nanomaterial that were not always explained by the release of Ag ions in clams at both salinities; such impacts were particularly characterized by induction of oxidative stress, cell damage, and impairment of energetic levels. Burrowing of clams was affected by the stabilizing agent depending on the salinity tested, with stronger effects at 15 psu. Finally, the present study highlighted salinity-dependent changes in the physiology of estuarine bivalves. Environ Toxicol Chem 2016;35:2550-2561. © 2016 SETAC.

Adaptation of the Daphnia sp. acute toxicity test: miniaturization and prolongation for the testing of nanomaterials.

Manufacturing of nanomaterials (NMs) is often complex and expensive, and their environmental risks are poorly understood or even unknown. An economization of testing NMs is therefore desirable, which can be achieved by miniaturizing test systems. However, the downsizing of test vessels and volumes can enlarge the surface/volume ratio (SVR) which in turn can affect the bioavailable concentration of adsorbing substances like NMs. The present study focused on the miniaturization of the acute toxicity test with Daphnia magna. The adaptations were verified with three reference substances, the non-adsorbing potassium dichromate (K2Cr2O7) and as potentially highly-adsorbing substances silver nanoparticles (AgNPs) and silver nitrate (AgNO3). The miniaturized test was conducted in 24-well microtiter plates (MT) and simultaneously compared to the OECD standard test (ST). Furthermore, the test duration was prolonged from 48 to 96 h since NMs tend to show effects only after extended exposure. The toxicity of K2Cr2O7 and AgNPs continued to increase within the prolonged test span. The test comparisons with K2Cr2O7 did not reveal any significant differences between ST and MT. AgNO3 toxicity was significantly decreased in MT compared to ST due to the enlarged SVR. The toxicity of AgNPs in MT after 24 h was equal to ST. Contrary to our expectations an exposure longer than 24 h resulted in an increase of AgNP toxicity in MT, possibly due to enhanced dissolution of silver. Microtiter plates are appropriate alternative test vessels for the Daphnia sp. acute toxicity test; thus, its miniaturization is feasible. The enlarged SVR has to be taken into account since it can affect the toxicity of potentially adsorbing substances. Furthermore, the standard test duration of 48 h might underestimate the toxicity of many substances, especially of NMs.

Quantitative assessment of hemolymph metabolites in two physiological states and two populations of the land snail Helix pomatia.

Hemolymph metabolite composition in ectothermic species is mainly constrained by trophic and climatic habitat conditions. In temperate regions, ectothermic species have to face subzero temperatures in winter, to which they typically respond with a state of inactivity. With use of ultra-performance liquid chromatography and gas chromatography-mass spectrometry techniques, we investigated the hemolymph metabolite composition of the land snail Helix pomatia with respect to physiological states (activity and hibernation) in a mountain population (800 m above sea level) and a valley population (150 m above sea level) in Germany. The dry masses of active snails as well as the saccharide and amino acid concentrations in active snails were higher in the mountain population than in the valley population. These differences between populations might reflect differences in microhabitat conditions, such as climate and vegetal food, and consequent differences in metabolic activity. Galactose was the most abundant component in hemolymph besides glucose. Both saccharides might indicate glycolytic activity, which could provide energy for locomotion and foraging. In hibernation, glutamate, α-alanine, glycine, aspartate, serine, homoserine, hydroxyproline, glycerol, and triglycerides were accumulated in both populations. The concentrations were correlated with a decrease in body supercooling point. Therefore, these metabolites might have a role in the cold hardiness of H. pomatia that should be further investigated in a functional study.

Adjustment of metabolite composition in the haemolymph to seasonal variations in the land snail Helix pomatia.

In temperate regions, land snails are subjected to subzero temperatures in winter and hot temperatures often associated to drought in summer. The response to these environmental factors is usually a state of inactivity, hibernation and aestivation, respectively, in a temperature and humidity buffered refuge, accompanied by physiological adjustments to resist cold or heat stress. We investigated how environmental factors in the microhabitat and body condition influence the metabolite composition of haemolymph of the endangered species Helix pomatia. We used UPLC and GC-MS techniques and analyzed annual biochemical variations in a multivariate model. Hibernation and activity months differed in metabolite composition. Snails used photoperiod as cue for seasonal climatic variations to initiate a physiological state and were also highly sensitive to temperature variations, therefore constantly adjusting their physiological processes. Galactose levels gave evidence for the persistence of metabolic activity with energy expenditure during hibernation and for high reproductive activity in June. Triglycerides accumulated prior to hibernation might act as cryoprotectants or energy reserves. During the last month of hibernation snails activated physiological processes related to arousal. During activity, protein metabolism was reflected by high amino acid level. An exceptional aestivation period was observed in April giving evidence for heat stress responses, like the protection of cells from dehydration by polyols and saccharides, the membrane stabilization by cholesterol and enhanced metabolism using the anaerobic succinic acid pathway to sustain costly stress responses. In conclusion, physiological adjustments to environmental variations in Helix pomatia involve water loss regulation, cryoprotectant or heatprotectant accumulation.

Evaluation of the clinimetric properties of the Early Inflammatory Arthritis--self-administered comorbidity questionnaire.

OBJECTIVES: To adapt the self-administered comorbidity questionnaire (SCQ) into the Early Inflammatory Arthritis-SCQ (EIA-SCQ) and assess its clinimetric properties in EIA. METHODS: The EIA-SCQ and indices of disease activity, function, pain, health-related quality of life (HRQoL) and health resource utilization were administered to 320 patients with EIA. Twenty patients completed the EIA-SCQ a second time 1 week later. Construct validity was evaluated by testing the hypotheses that a valid comorbidity index would correlate well with age, weakly with HRQoL and recent resource utilization and poorly with indices of disease activity, function and pain. RESULTS: The intra-class correlation coefficient between repeat scores was 0.93 (95% CI 0.83-0.97). Kappa values for individual items ranged from 0.64 to 1.0. EIA-SCQ scores correlated moderately with age (Tau B = 0.29, P < 0.001) and weakly with function (HAQ-DI Tau B = 0.09, P = 0.03), pain (McGill Pain Questionnaire Tau B = 0.09, P = 0.05), some measures of HRQoL [the SF-36 mental component score (MCS) Tau B = - 0.08, P < 0.05; World Health Organization Disease Assessment Schedule II score Tau B = 0.09, P = 0.03] and a measure of resource utilization (number of tests in the last 4 months Tau B = 0.10, P = 0.04). The EIA-SCQ did not correlate with other measures of disease activity, another HRQoL measure [SF-36 physical component score (PCS)] or other measures of resource utilization. CONCLUSIONS: The EIA-SCQ is reliable and valid for use in EIA. It has the potential to become a useful measure of comorbidity in outcome studies of EIA when the resources for a full medical chart review are unavailable.

Symptoms of depression predict the trajectory of pain among patients with early inflammatory arthritis: a path analysis approach to assessing change.

OBJECTIVE: To assess the longitudinal relationships, including directionality, among chronic pain, symptoms of depression, and disease activity in patients with early inflammatory arthritis (EIA). METHODS: One hundred eighty patients with EIA completed an examination, including swollen joint count, and were administered the Center for Epidemiological Studies Depression Scale (CES-D) and the McGill Pain Questionnaire (MPQ) at 2 timepoints 6 months apart. Cross-lagged panel path analysis was used to simultaneously assess concurrent and longitudinal relationships among pain, symptoms of depression, and number of swollen joints. RESULTS: Pain, symptoms of depression, and number of swollen joints decreased over time (p < 0.001) and were prospectively linked to pain, symptoms of depression, and number of swollen joints, respectively, at 6 months. Symptoms of depression and pain were correlated with each other at baseline (0.47) and at 6-month followup assessments (0.28). Baseline symptoms of depression significantly predicted pain symptoms at 6 months (standardized regression coefficient = 0.28, p = 0.001), whereas pain and disease activity did not predict the course of any other variable after controlling for baseline values. CONCLUSION: Symptoms of depression predicted the trajectory of pain from baseline to 6 months. In addition, there were reciprocal/bidirectional associations between pain and symptoms of depression over time. More research is needed to better understand the relationship between pain and depressive symptoms and how to best manage patients with EIA who have high levels of both.

Safety and efficacy of long-term intraarticular steroid injections in osteoarthritis of the knee: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To evaluate the safety and efficacy of long-term intraarticular (IA) steroid injections for knee pain related to osteoarthritis (OA). METHODS: In a randomized, double-blind trial, 68 patients with OA of the knee received IA injections of triamcinolone acetonide 40 mg (34 patients) or saline (34 patients) into the study knee every 3 months for up to 2 years. The primary outcome variable was radiologic progression of joint space narrowing of the injected knee after 2 years. Measurements of minimum joint space width were performed by an automated computerized method on standardized fluoroscopically guided radiographs taken with the patient standing and with the knee in a semiflexed position. The clinical efficacy measure of primary interest was the pain subscale from the Western Ontario and McMaster Universities OA Index (WOMAC). Efficacy measures of secondary interest were the total score on the WOMAC, physician's global assessment, patient's global assessment, patient's assessment of pain, range of motion (ROM) of the affected knee, and 50-foot walking time. Clinical symptoms were assessed just before each injection. RESULTS: At the 1-year and 2-year followup evaluations, no difference was noted between the two treatment groups with respect to loss of joint space over time. The steroid-injected knees showed a trend toward greater symptom improvement, especially at 1 year, for the WOMAC pain subscale, night pain, and ROM values (P = 0.05) compared with the saline-injected knees. Using area under the curve analyses, knee pain and stiffness were significantly improved throughout the 2-year study by repeated injections of triamcinolone acetonide, but not saline (P < 0.05). CONCLUSION: Our findings support the long-term safety of IA steroid injections for patients with symptomatic knee OA. No deleterious effects of the long-term administration of IA steroids on the anatomical structure of the knee were noted. Moreover, long-term treatment of knee OA with repeated steroid injections appears to be clinically effective for the relief of symptoms of the disease.