Vanadium Toxicity Monitored by Fertilization Outcomes and Metal Related Proteolytic Activities in Paracentrotus lividus Embryos

Metal pharmaceutical residues often represent emerging toxic pollutants of the aquatic environment, as wastewater treatment plants do not sufficiently remove these compounds. Recently, vanadium (V) derivatives have been considered as potential therapeutic factors in several diseases, however, only limited information is available about their impact on aquatic environments. This study used sea urchin embryos (Paracentrotus lividus) to test V toxicity, as it is known they are sensitive to V doses from environmentally relevant to very cytotoxic levels (50 nM; 100 nM; 500 nM; 1 uM; 50 uM; 100 uM; 500 uM; and 1 mM).We used two approaches: The fertilization test (FT) and a protease detection assay after 36 h of exposure. V affected the fertilization percentage and increased morphological abnormalities of both egg and fertilization envelope, in a dose-dependent manner. Moreover, a total of nine gelatinases (with apparent molecular masses ranging from 309 to 22 kDa) were detected, and their proteolytic activity depended on the V concentration. Biochemical characterization shows that some of them could be aspartate proteases, whereas substrate specificity and the Ca2+/Zn2+ requirement suggest that others are similar to mammalian matrix metalloproteinases (MMPs)

Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species

Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species. These different sensitivities highlight the importance of testing toxicity in several species for risk assessment. The strong negative effects of Gd on calcification in plutei, together with the plethora of marine species that have calcifying larvae, indicates that Gd pollution is urgent issue that needs to be addressed

Toxicological Impact of Rare Earth Elements (REEs) on the Reproduction and Development of Aquatic Organisms Using Sea Urchins as Biological Models

The growing presence of lanthanides in the environment has drawn the attention of the scientific community on their safety and toxicity. The sources of lanthanides in the environment include diagnostic medicine, electronic devices, permanent magnets, etc. Their exponential use and the poor management of waste disposal raise serious concerns about the quality and safety of the ecosystems at a global level. This review focused on the impact of lanthanides in marine organisms on reproductive fitness, fertilization and embryonic development, using the sea urchin as a biological model system. Scientific evidence shows that exposure to lanthanides triggers a wide variety of toxic insults, including reproductive performance, fertilization, redox metabolism, embryogenesis, and regulation of embryonic gene expression. This was thoroughly demonstrated for gadolinium, the most widely used lanthanide in diagnostic medicine, whose uptake in sea urchin embryos occurs in a time- and concentration-dependent manner, correlates with decreased calcium absorption and primarily affects skeletal growth, with incorrect regulation of the skeletal gene regulatory network. The results collected on sea urchin embryos demonstrate a variable sensitivity of the early life stages of different species, highlighting the importance of testing the effects of pollution in different species. The accumulation of lanthanides and their emerging negative effects make risk assessment and consequent legislative intervention on their disposal mandatory

Large Artery Remodeling and Dynamics following Simulated Microgravity by Prolonged Head-Down Tilt Bed Rest in Humans

The effects of simulated microgravity on the static and dynamic properties of large arteries are still mostly unknown. The present study evaluated, using an integrated vascular approach, changes in structure and function of the common carotid and femoral arteries (CCA and CFA) after prolonged head-down tilt bed rest (HDTBR). Ten healthy men were enrolled in a 5-week HDTBR study endorsed by the Italian Space Agency (ASI). Arterial geometry, flow, stiffness, and shear rate were evaluated by ultrasound. Local carotid pulse pressure and wave reflection were studied by applanation tonometry. After five weeks of HDTBR, CFA showed a decrease in lumen diameter without significant changes in wall thickness (IMT), resulting in an inward remodeling. Local carotid pulse pressure decreased and carotid-to-brachial pressure amplification increased. The ratio of systolic-to-diastolic volumetric flow in CFA decreased, whereas in CCA it tended to increase. Indices of arterial stiffness and shear rate did not change during HDTBR, either in CCA or CFA. In summary, prolonged HDTBR has a different impact on CCA and CFA structure and flow, probably depending on the characteristics of the vascular bed perfuse

Toxicity induced by Gadolinium ions on sea urchin embryos: comparison among phylogenetically distant species and focus on stress response and skeletogenesis.

Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a lanthanide metal whose chelates are employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the effects of exposure to sublethal Gd concentrations on the development of four phylogenetically and geographically distant sea urchin species: two Mediterranean, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Sensitivity to Gd greatly varied, with EC50 ranging from 56 nM to 132 µM across the four species. Measures of the Gd and Ca content inside embryos showed a time- and dose-dependent increase in Gd, in parallel with a reduction in Ca. In all the four species, we observed a general delay of embryo development at 24h post-fertilization, and a strong inhibition of skeleton growth at 48h. Further experiments were carried out on P. lividus embryos: RT-PCR gene expression analysis showed the misregulation of several genes implicated both in the skeletogenic and the left-right axis specification networks. WB analysis showed an increase of the LC3 autophagic marker at 24 and 48h. Confocal microscopy studies confirmed the increased number of autophagosomes and autophagolysosomes and showed no apoptotic induction. The results show the hazard of Gd in the marine environment, indicating that Gd is able to affect three different levels in sea urchin embryos: morphogenesis, stress response such as autophagy, and gene expression. Results highlight that pollution assays based on only one species can be misleading with respect to hazard risk assessment

Involvement of fractalkine and macrophage inflammatory protein-1 alpha in moderate-severe depression.

Moderate-severe depression (MSD) is linked to overexpression of proinflammatory cytokines and chemokines. Fractalkine (FKN) and macrophage inflammatory protein-1 alpha (MIP-1alpha) are, respectively, members of CX3C and C-C chemokines, and both are involved in recruiting and activating mononuclear phagocytes in the central nervous system. We analysed the presence of FKN and MIP-1alpha in sera of untreated MSD patients and healthy donors. High FKN levels were observed in all MSD patients as compared with values only detectable in 26% of healthy donors. MIP-1alpha was measurable in 20% of patients, while no healthy donors showed detectable chemokine levels. In conclusion, we describe a previously unknown involvement of FKN in the pathogenesis of MSD, suggesting that FKN may represent a target for a specific immune therapy of this disease

Palytoxin and an Ostreopsis Toxin Extract Increase the Levels of mRNAs Encoding Inflammation-Related Proteins in Human Macrophages via p38 MAPK and NF-κB

BACKGROUND: Palytoxin and, likely, its analogues produced by the dinoflagellate genus Ostreopsis, represent a class of non-proteinaceous compounds displaying high toxicity in animals. Owing to the wide distribution and the poisonous effects of these toxins in humans, their chemistry and mechanism of action have generated a growing scientific interest. Depending on the exposure route, palytoxin and its Ostreopsis analogues may cause several adverse effects on human health, including acute inflammatory reactions which seem more typical of cutaneous and inhalation contact. These observations have led us to hypothesize that these toxins may activate pro-inflammatory signalling cascades. METHODOLOGY AND PRINCIPAL FINDINGS: Here we demonstrate that palytoxin and a semi-purified Ostreopsis cf. ovata toxin extract obtained from a cultured strain isolated in the NW Adriatic Sea and containing a putative palytoxin and all the ovatoxins so far known--including the recently identified ovatoxin-f--significantly increase the levels of mRNAs encoding inflammation-related proteins in immune cells, i.e. monocyte-derived human macrophages, as assessed by Real-Time PCR analysis. Western immunoblot and electrophoretic mobility shift assays revealed that nuclear transcription factor -κB (NF-κB) is activated in cells exposed to toxins in coincidence with reduced levels of the inhibitory protein IκB-α. Moreover, Mitogen-Activated Protein Kinases (MAPK) were phosphorylated in response to palytoxin, as also reported by others, and to the Ostreopsis toxin extract, as shown here for the first time. By using specific chemical inhibitors, the involvement of NF-κB and p38 MAPK in the toxin-induced transcription and accumulation of Cycloxigenase-2, Tumor Necrosis Factor-α, and Interleukin-8 transcripts has been demonstrated. CONCLUSIONS AND SIGNIFICANCE: The identification of specific molecular targets of palytoxin and its Ostreopsis analogues, besides contributing to expand the still limited knowledge of the intracellular signalling cascades affected by these toxins, may have important implications in setting up focused pharmacological interventions, replacing currently used symptomatic treatments