Cation Composition Influences the Toxicity of Salinity to Freshwater Biota.

The effects of salinization on freshwater ecosystems have been estimated by testing sodium chloride (NaCl) since it is the most widely used salt as a deicing agent and Na+ and Cl- ions are the most representative in seawater composition. However, calcium, magnesium, and/or potassium are starting to be proposed as potential surrogates for NaCl, but for which ecotoxicological effects are less explored. This study aimed to identify (i) the less toxic salt to freshwater biota to be suggested as a safer alternative deicer and (ii) to contribute to the lower tiers of salinity risk assessment frameworks by identifying a more suitable surrogate salt than NaCl. The battery of ecotoxicity assays with five key trophic level species showed that among the tested salts (MgCl2, CaCl2, and KCl), KCl and CaCl2 seemed to induce the highest and lowest toxicity, respectively, compared with NaCl. CaCl2 is suggested as a safer alternative for use as a deicer and KCl as a surrogate for the risk assessment of seawater intrusion in coastal regions. These results enrich the salt toxicity database aiming to identify and propose more suitable surrogate salts to predict the effects of salinization to a broader extent.

Calcium Chloride Toxicology for Food Safety Assessment Using Zebrafish (Danio rerio) Embryos.

The salt calcium chloride (CaCl2) is widely used in industry as a food additive; levels for human consumption are regulated by international or governmental agencies. Generally, the food industry relies on toxicity studies conducted in mammals such as mice, rats, and rabbits for determining food safety. However, testing in mammals is time-consuming and expensive. Zebrafish have been used in a range of toxicological analyses and offer advantages with regard to sensitivity, time, and cost. However, information in not available with regard to whether the sensitivity of zebrafish to CaCl2 is comparable to the concentrations of CaCl2 used as food additives. The aim of this study was to compare the CaCl2 tolerance of zebrafish embryos and larvae with concentrations currently approved as food additives. Acute toxicity, embryotoxicity, cardiotoxicity, and neurotoxicity assays were used to determine the threshold toxic concentration of CaCl2 in zebrafish embryos and larvae. The data showed that doses above 0.4% had toxic effects on development and on the activity of the cardiac and neuronal systems. Furthermore, all embryos exposed to 0.8 and 1.6% of CaCl2 died after 24 hpf. These findings are consistent with the limits of CaCl2 concentrations approved by Codex Alimentarius. Therefore, zebrafish embryos could be suitable for screening food additives.

Trimethylamine N-Oxide Promotes Abdominal Aortic Aneurysm Formation by Aggravating Aortic Smooth Muscle Cell Senescence in Mice.

Trimethylamine N-oxide (TMAO) has been linked to cardiovascular disease morbidity and mortality. However, the role of TMAO in the development of abdominal aortic aneurysms (AAAs) is not known. This study investigated the association between TMAO and AAA formation. TMAO and saline were added to the drinking water of angiotensin II (AngII)- and calcium chloride (CaCl2)-induced AAA model mice, respectively. After 4 weeks, the effects of TMAO on AAA development were determined by histology and immunohistology of aortic tissue. The in vitro effects of TMAO were also examined in mouse aortic smooth muscle cells (SMCs). The maximal aortic diameter, incidence of AAA, and degree of elastin degradation were significantly increased in TMAO-treated mice. TMAO also increased the accumulation of the senescence markers p21 and p16, as well as of reactive oxygen species (ROS), matrix metalloproteinase-2 (MMP2), and matrix metalloproteinase-9 (MMP9) in vivo and in vitro. TMAO promoted AAA development in mouse AAA models induced by AngII and CaCl2 by a mechanism involving cellular senescence.

MLKL and CaMKII Are Involved in RIPK3-Mediated Smooth Muscle Cell Necroptosis.

Receptor interacting protein kinase 3 (RIPK3)-mediated smooth muscle cell (SMC) necroptosis has been shown to contribute to the pathogenesis of abdominal aortic aneurysms (AAAs). However, the signaling steps downstream from RIPK3 during SMC necroptosis remain unknown. In this study, the roles of mixed lineage kinase domain-like pseudokinase (MLKL) and calcium/calmodulin-dependent protein kinase II (CaMKII) in SMC necroptosis were investigated. We found that both MLKL and CaMKII were phosphorylated in SMCs in a murine CaCl2-driven model of AAA and that Ripk3 deficiency reduced the phosphorylation of MLKL and CaMKII. In vitro, mouse aortic SMCs were treated with tumor necrosis factor α (TNFα) plus Z-VAD-FMK (zVAD) to induce necroptosis. Our data showed that both MLKL and CaMKII were phosphorylated after TNFα plus zVAD treatment in a time-dependent manner. SiRNA silencing of Mlkl-diminished cell death and administration of the CaMKII inhibitor myristoylated autocamtide-2-related inhibitory peptide (Myr-AIP) or siRNAs against Camk2d partially inhibited necroptosis. Moreover, knocking down Mlkl decreased CaMKII phosphorylation, but silencing Camk2d did not affect phosphorylation, oligomerization, or trafficking of MLKL. Together, our results indicate that both MLKL and CaMKII are involved in RIPK3-mediated SMC necroptosis, and that MLKL is likely upstream of CaMKII in this process.

miR­101a­3p overexpression prevents acetylcholine­CaCl2­induced atrial fibrillation in rats via reduction of atrial tissue fibrosis, involving inhibition of EZH2.

Atrial fibrillation (AF), a clinically common heart arrhythmia, can result in left ventricular hypofunction, embolism and infarction. MicroRNA (miR)­101a­3p is lowly expressed in atrial tissues of patients with AF, but its role in AF remains unknown. In the present study, an AF model in rats was established via intravenous injection of acetylcholine (Ach)­CaCl2. The downregulation of miR­101a­3p and upregulation of enhancer of zeste 2 homolog 2 (EZH2) were observed in AF model rats, indicating the involvement of miR­101a­3p and EZH2 in AF development. To study the effect of miR­101a­3p on AF in vivo, AF model rats were intramyocardially injected with lentivirus expressing miR­101a­3p. Electrocardiogram analysis identified that miR­101a­3p overexpression restored disappeared P wave and R­R interphase changes in Ach­CaCl2­induced rats. Overexpression of miR­101a­3p also increased the atrial effective refractory period, reduced AF incidence and shortened duration of AF. Histological changes in atrial tissues were observed after H&E and Masson staining, which demonstrated that miR­101a­3p reduced atrial remodeling and fibrosis in AF model rats. Moreover, EZH2 expression was downregulated in atrial tissues by miR­101a­3p induction. Immunohistochemistry for collagen Ⅰ and collagen III revealed a reduction in atrial collagen synthesis following miR­101a­3p overexpression in AF model rats. Additionally, miR­101a­3p lowered the expression of pro­fibrotic biomarkers, including TGF­ß1, connective tissue growth factor, fibronectin and α­smooth muscle actin. The luciferase reporter assay results also indicated that EZH2 was a target gene of miR­101a­3p. Taken together, it was found that miR­101a­3p prevented AF in rats possibly via inhibition of collagen synthesis and atrial fibrosis by targeting EZH2, which provided a potential target for preventing AF.

Immune checkpoint programmed death-1 mediates abdominal aortic aneurysm and pseudoaneurysm progression.

PURPOSE: The causes and pathogenetic mechanisms underlying abdominal aortic aneurysms (AAAs) and pseudoaneurysms are not fully understood. We hypothesized that inhibiting programmed death-1 (PD-1) can decrease AAA and pseudoaneurysm formation in mouse and rat models. METHODS: Human AAA samples were examined in conjunction with an adventitial calcium chloride (CaCl2) application mouse model and an aortic patch angioplasty rat model. Single-dose PD-1 antibody (4 mg/kg) or BMS-1 (PD-1 inhibitor-1) (1 mg/kg) was administered by intraperitoneal (IP) or intraluminal injection. In the intramural injection group, PD-1 antibody was injected after CaCl2 incubation. The rats were divided into three groups: (1) the control group was only decellularized without other special treatment, (2) the PD-1 antibody-coated patch group, and (3) the BMS-1 coated patch group. Patches implanted in the rat abdominal aorta were harvested on day 14 after implantation and analyzed. RESULTS: Immunohistochemical analysis showed PD-1-positive cells, PD-1 and CD3, PD-1 and CD68, and PD-1 and α-actin co-expressed in the human AAA samples. Intraperitoneal (IP) injection or intraluminal injection of PD-1antibody/BMS-1 significantly inhibited AAA progression. PD-1 antibody and BMS-1 were each successfully conjugated to decellularized rat thoracic artery patches, respectively, by hyaluronic acid. Patches coated with either humanized PD-1 antibody or BMS-1 can also inhibit pseudoaneurysm progression and inflammatory cell infiltration. CONCLUSION: PD-1 pathway inhibition may be a promising therapeutic strategy for inhibiting AAA and pseudoaneurysm progression.

Inhibition of Notch1-mediated inflammation by intermedin protects against abdominal aortic aneurysm via PI3K/Akt signaling pathway.

The Notch1-mediated inflammatory response participates in the development of abdominal aortic aneurysm (AAA). The vascular endogenous bioactive peptide intermedin (IMD) plays an important role in maintaining vascular homeostasis. However, whether IMD inhibits AAA by inhibiting Notch1-mediated inflammation is unclear. In this study, we found Notch intracellular domain (NICD) and hes1 expression were higher in AAA patients' aortas than in healthy controls. In angiotensin II (AngII)-induced AAA mouse model, IMD treatment significantly reduced AAA incidence and maximal aortic diameter. IMD inhibited AngII-enlarged aortas and -degraded elastic lamina, reduced NICD, hes1 and inflammatory factors expression, decreased infiltration of CD68 positive macrophages and the NOD-like receptor family pyrin domain containing 3 protein level. IMD inhibited lipopolysaccharide-induced macrophage migration in vitro and regulated macrophage polarization. Moreover, IMD overexpression significantly reduced CaCl2-induced AAA incidence and down-regulated NICD and hes1 expression. However, IMD deficiency showed opposite results. Mechanically, IMD treatment significantly decreased cleavage enzyme-a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) level. Pre-incubation with IMD17-47 (IMD receptors blocking peptide) and the phosphatidylinositol 3-kinase/protein kinase b (PI3K/Akt) inhibitor LY294002 reversed ADAM10 level. In conclusion, exogenous and endogenous IMD could inhibit the development of AAA by inhibiting Notch1 signaling-mediated inflammation via reducing ADAM10 through IMD receptor and PI3K/Akt pathway.

Loss of SIRT1 in diabetes accelerates DNA damage-induced vascular calcification.

AIMS: Vascular calcification is a recognized predictor of cardiovascular risk in the diabetic patient, with DNA damage and accelerated senescence linked to oxidative stress-associated pathological calcification. Having previously shown that systemic SIRT1 is reduced in diabetes, the aim was to establish whether SIRT1 is protective against a DNA damage-induced senescent and calcified phenotype in diabetic vascular smooth muscle cells (vSMCs). METHODS AND RESULTS: Immunohistochemistry revealed decreased SIRT1 and increased DNA damage marker expression in diabetic calcified arteries compared to non-diabetic and non-calcified controls, strengthened by findings that vSMCs isolated from diabetic patients show elevated DNA damage and senescence, assessed by the Comet assay and telomere length. Hyperglycaemic conditions were used and induced DNA damage and enhanced senescence in vSMCs in vitro. Using H2O2 as a model of oxidative stress-induced DNA damage, pharmacological activation of SIRT1 reduced H2O2 DNA damage-induced calcification, prevented not only DNA damage, as shown by reduced comet tail length, but also decreased yH2AX foci formation, and attenuated calcification. While Ataxia Telanglectasia Mutated (ATM) expression was reduced following DNA damage, in contrast, SIRT1 activation significantly increased ATM expression, phosphorylating both MRE11 and NBS1, thus allowing formation of the MRN complex and increasing activation of the DNA repair pathway. CONCLUSION: DNA damage-induced calcification is accelerated within a diabetic environment and can be attenuated in vitro by SIRT1 activation. This occurs through enhancement of the MRN repair complex within vSMCs and has therapeutic potential within the diabetic patient.

Prevention of CaCl2-induced aortic inflammation and subsequent aneurysm formation by the CCL3-CCR5 axis.

Inflammatory mediators such as cytokines and chemokines are crucially involved in the development of abdominal aortic aneurysm (AAA). Here we report that CaCl2 application into abdominal aorta induces AAA with intra-aortic infiltration of macrophages as well as enhanced expression of chemokine (C-C motif) ligand 3 (CCL3) and MMP-9. Moreover, infiltrating macrophages express C-C chemokine receptor 5 (CCR5, a specific receptor for CCL3) and MMP-9. Both Ccl3-/- mice and Ccr5-/- but not Ccr1-/- mice exhibit exaggerated CaCl2-inducced AAA with augmented macrophage infiltration and MMP-9 expression. Similar observations are also obtained on an angiotensin II-induced AAA model. Immunoneutralization of CCL3 mimics the phenotypes observed in CaCl2-treated Ccl3-/- mice. On the contrary, CCL3 treatment attenuates CaCl2-induced AAA in both wild-type and Ccl3-/- mice. Consistently, we find that the CCL3-CCR5 axis suppresses PMA-induced enhancement of MMP-9 expression in macrophages. Thus, CCL3 can be effective to prevent the development of CaCl2-induced AAA by suppressing MMP-9 expression.

Pharmacological Inhibition of Cathepsin S Suppresses Abdominal Aortic Aneurysm in Mice.

OBJECTIVE: Evidence suggests that cathepsin S (CTSS), a potent mammalian elastase, participates in abdominal aortic aneurysm (AAA) formation. This study examines the hypothesis that pharmacological inhibition of CTSS with an α-ketoamide based compound 6r might suppress AAA in mice. METHODS: Experimental study of the CaCl2 induced AAA model in B6 mice and angiotensin II (AngII) infused AAA model in ApoE-/- mice. The effects of intraperitoneal administration of 6r (25 mg/kg) and vehicle every three days since one day after AAA induction were evaluated at 28 days using CaCl2 induced (n = 12 per group) and AngII infused (n = 8 per group) models. Additionally, the effects of post-treatment with 6r and vehicle from seven days or 14 days after AAA induction were evaluated at 28 days using the CaCl2 induced model (n = 6 per group). Aortic samples were harvested for histological and biochemical analyses, including cathepsin levels, Verhoeff Van Gieson staining, TUNEL assay, and immunostaining for macrophages. RESULTS: In the CaCl2 induced model, treatment with 6r suppressed aortic dilatation observed in vehicle treated controls (median: 0.58 vs. 0.92 mm; p < .001), along with reduced CTSS and cathepsin K (CTSK) levels (both p < .001), preserved elastin integrity (p < .001), fewer medial apoptotic cells (p = .012) and less macrophage infiltration (p = .041). In the AngII infused model, the aortic diameter was smaller in 6r treated mice than in vehicle treated controls (median: 0.95 vs. 1.84 mm; p = .047). The levels of CTSS (p < .001) and CTSK (p = .033) and the numbers of elastin breaks (p < .001), medial apoptotic cells (p < .001) and infiltrating macrophages (p = .030) were attenuated under 6r treatment. Finally, post-treatment with 6r from seven days (p = .046) or 14 days (p = .012) after AAA induction limited CaCl2 induced AAA. CONCLUSION: Pharmacological inhibition of CTSS by 6r suppresses AAA formation in mice. Also, post-treatment with 6r retards mouse AAA progression. These findings provide proof of concept validation for CTSS as a potential therapeutic target in AAA.

Deficiency of immunoglobulin E protects mice from experimental abdominal aortic aneurysms.

Allergic asthma with high plasma IgE levels is a significant risk factor of human abdominal aortic aneurysm (AAA). This study tests a direct role of IgE in angiotensin-II (Ang-II) perfusion- and peri-aortic CaCl2 injury-induced AAA in mice. In both models, IgE-deficiency in Apoe-/- Ige-/- mice blunts AAA growth and reduces lesion accumulation of macrophages, CD4+ and CD8+ T cells, and lesion MHC class-II expression, CD31+ microvessel growth, and media smooth muscle cell loss, compared with those from Apoe-/- control mice. Real time-PCR reveals significant reductions in expression of neutrophil chemoattractants MIP-2α and CXCL5 in AAA lesions or macrophages from Apoe-/- Ige-/- mice, along with reduced lesion Ly6G+ neutrophil accumulation. Consistent with reduced lesion inflammatory cell accumulation, we find significant reductions of plasma and AAA lesion IL6 expression in Apoe-/- Ige-/- mice. Immunofluorescent staining and FACS analysis show that AAA lesion neutrophils express FcεR1. Mechanistic study demonstrates that IgE induces neutrophil FcεR1 expression, activates MAPK signaling, and promotes IL6 production. This study supports a direct role of IgE in AAA by promoting lesion chemokine expression, inflammatory cell accumulation, MAPK signaling, and cytokine expression. IgE inhibition may represent a novel therapeutic approach in AAA management.

Brg1 trans-activates endothelium-derived colony stimulating factor to promote calcium chloride induced abdominal aortic aneurysm in mice.

Endothelial cell derived secretive factors play pivotal roles maintaining the homeostasis by influencing the behaviors of other cells. When dysregulated, these factors may contribute to the disruption of physiological integrity and promote disease genesis in a number of different tissues and organs. In the present study we investigated how targeted deletion of brahma related gene 1 (Brg1), a chromatin remodeling protein, in endothelium might affect the pathogenesis of abdominal aortic aneurysm (AAA) induced by calcium chloride (CaCl2). We report here that compared to the wild type (WT) littermates, endothelial conditional Brg1 knockout (ecKO) mice exhibited an attenuated phenotype of AAA. Immunostaining and quantitative PCR analyses showed that vascular inflammation was suppressed in ecKO mice as opposed to WT mice likely due to diminished recruitment of macrophages. Further examination revealed that Brg1 deficiency led to a reduction in colony stimulating factor 1 (CSF1) levels. In cultured endothelial cells, Brg1 cooperated with histone H3K9 demethylase KDM3A to activate CSF1 transcription and macrophage recruitment thereby perpetuating vascular inflammation. Depletion of BRG1 or KDM3A in endothelial cells dampened CSF1 production and attenuated macrophage chemotaxis. Therefore, our data suggest that epigenetic activation of CSF1 transcription by Brg1 may contribute to AAA pathogenesis.

Effects of osteoprotegerin/TNFRSF11B in two models of abdominal aortic aneurysms.

Osteoprotegerin (OPG), additionally termed tumor necrosis factor receptor superfamily member 11B, is produced by vascular smooth muscle cells (VSMCs) and endothelial cells in the vasculature, and its release may be modulated by pro­inflammatory cytokines, including interleukin­1ß and tumor necrosis factor­α. The present study investigated the effects of treatment with low­dose human recombinant OPG on abdominal aortic aneurysm (AAA) development in mice. Mice were treated with 1 µg human recombinant OPG four times (or vehicle) for 2 weeks prior to inducing AAA. A total of two different models for inducing AAA were used to investigate the hypothesis as to whether OPG is involved in key events of AAA development, using osmotic mini­pumps with angiotensin II in apolipoprotein­E (ApoE­/­) mice for 28 days or using periaortic application of CaCl2 on the aorta in C57Bl/6J mice for 14 days. OPG was continuously administered during the experimental period. Histological staining using Masson's trichrome, Verhoeff's van­Gieson and picro­sirius red, in addition to reverse transcription­quantitative polymerase chain reaction analysis of various markers, were used to analyze phenotypic alterations. Treatment with OPG had no inhibitory effect on AAA development in the angiotensin II model in ApoE­/­ mice, which developed suprarenal aneurysms, although it increased vessel wall thickness of the aorta and total collagen in C57Bl/6J mice using the CaCl2 model that induced infrarenal dilation of the aorta. Treatment with OPG did not inhibit aneurysm development and key events, including inflammation, extracellular matrix or VSMC remodeling, in aortas from OPG­treated mice with periaortic treatment with CaCl2. The results indicated that mice treated with low levels of human recombinant OPG may have a more stable aneurysmal phenotype due to compensatory production of collagen and increased vessel wall thickness of the aorta, potentially protecting the aneurysm from rupture. Further studies investigating rupture models of AAA in addition to using higher levels of OPG are require to verify this speculation. Furthermore, treatment with low levels of OPG in patients with AAA may represent a novel therapeutic strategy for the treatment of AAA as well as attenuate the adverse effects associated with the administration of normal and high dosages of OPG.

Un paso más en seguridad en nutrición parenteral pediátrica / On step more in safety in pediatric parenteral nutrition

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Taurine Reverses Atrial Structural Remodeling in Ach-Cacl2 Induced Atrial Fibrillation Rats.

Taurine has been reported to have anti-arrhythmia effects, but the anti-atrial fibrillation (AF) effects and its mechanism remain incompletely understood. In the present study, the therapy effects and partly mechanisms were investigated. AF animal model was established by intravenous administered with the mixture of acetylcholine (Ach) and CaCl2 (66 µg/mL + 10 mg/mL) (i.v.) for 7 days. The actions of taurine (99 mg/kg∙d, introgastric administration) on the levels of Hs-CRP, IL-6, TNF-α, MMP-9, AngII, the extent of the fibrosis and ultrastructural changes in left atrial were studied. The data showed that the serum levels of TNF-α, IL-6, AngII and the plasma levels of Hs-CRP and MMP-9 were significantly elevated in automatic recovery group relative to the control group (p < 0.01), which were all decreased by taurine administration (p < 0.01) similar to Verapamil treatment. Masson's trichrome staining of the left atrial tissue showed an obvious interstitial fibrosis in rats of automatic recovery group. The alteration could be reversed by additional taurine. Electron microscopy revealed that taurine administration could significantly alleviate the ultrastructural damage of atrial cells, and the effects were similar to the Verapamil treatment. In conclusion, the results suggested that taurine could inhibit the structural remodeling of AF in rats partly by decreasing the levels of inflammatory factors and profibrotic molecules, attenuating the extent of myocardial fibrosis and protecting the integrity of myocardial ultrastructure.

Taurine Prevents the Electrical Remodeling in Ach-CaCl2 Induced Atrial Fibrillation in Rats.

OBJECTIVE: To study the preventive actions and mechanism of taurine on the electrical remodeling in atrial fibrillation (AF) rats. METHODS: Male Wistar rats were injected with the mixture of acetylcholine (Ach) (66 µg/mL)-CaCl2 (10 mg/mL) (i.v.) for 7 days to establish AF model. Taurine was administered in drinking water 1 week before or at the same time of AF model establishment. The duration of AF was monitored by recording ECG of rats during the model establishment. At the end of the experiment, left atrial appendages were cut down to measure the effective refractory period (ERP) by S1-S2 double stimulation method; atrial tissues were collected in order to detect the concentration of K+ and taurine by flame atomic absorption spectrometry and ELISA respectively; total RNA were extracted from the atrium, gene expressions of Kv1.5, Kv4.3, Kir2.1, Kir3.4 were detected by semi-quantitative RT-PCR. RESULTS: Taurine administration effectively shortened the AF duration of rats and prolonged atrial ERP than the model and taurine depleted rats. In addition, atrial K+ level in taurine treated groups was significantly reduced nearly to the normal level. Moreover, the mRNA expression levels of Kir3.4 and Kv1.5 were significantly increased in the taurine preventive treated groups. CONCLUSIONS: Taurine can prevent the atrial electrical remodeling and decrease the duration of AF in rats by reducing the atrial K+ concentration and up-regulating mRNA expression levels of Kir3.4 and Kv1.5.

Impacts of road deicing salts on the early-life growth and development of a stream salmonid: Salt type matters.

The use of road deicing salts in regions that experience cold winters is increasing the salinity of freshwater ecosystems, which threatens freshwater resources. Yet, the impacts of environmentally relevant road salt concentrations on freshwater organisms are not well understood, particularly in stream ecosystems where salinization is most severe. We tested the impacts of deicing salts-sodium chloride (NaCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2)-on the growth and development of newly hatched rainbow trout (Oncorhynchus mykiss). We exposed rainbow trout to a wide range of environmentally relevant chloride concentrations (25, 230, 860, 1500, and 3000 mg Cl- L-1) over an ecologically relevant time period (25 d). We found that the deicing salts studied had distinct effects. MgCl2 did not affect rainbow trout growth at any concentration. NaCl had no effects at the lowest three concentrations, but rainbow trout length was reduced by 9% and mass by 27% at 3000 mg Cl- L-1. CaCl2 affected rainbow trout growth at 860 mg Cl- L-1 (5% reduced length; 16% reduced mass) and these effects became larger at higher concentrations (11% reduced length; 31% reduced mass). None of the deicing salts affected rainbow trout development. At sub-lethal and environmentally relevant concentrations, our results do not support the paradigm that MgCl2 is the most toxic deicing salt to fish, perhaps due to hydration effects on the Mg2+ cation. Our results do suggest different pathways for lethal and sub-lethal effects of road salts. Scaled to the population level, the reduced growth caused by NaCl and CaCl2 at critical early-life stages has the potential to negatively affect salmonid recruitment and population dynamics. Our findings have implications for environmental policy and management strategies that aim to reduce the impacts of salinization on freshwater organisms.

EPA Prevents the Development of Abdominal Aortic Aneurysms through Gpr-120/Ffar-4.

Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture with a high mortality rate. Although eicosapentaenoic acid (EPA) has been reported to prevent AAA formation, the mechanism by which EPA works on vascular smooth muscle cells is unknown. This study aimed to investigate the mechanism by which orally-administered EPA prevents the formation of severe AAAs that develop in Osteoprotegerin (Opg) knockout (KO) mice. In the CaCl2-induced AAA model, EPA attenuated the enhanced progression of AAAs in Opg-KO mice, including the increase in aortic diameter with destruction of elastic fibers in the media. Immunohistochemical analyses showed that EPA reduced the phosphorylation of transforming growth factor beta-activated kinase-1/Map3k7 (Tak-1) and c-Jun NH2-terminal kinase (JNK), as well as the expression of Matrix metalloproteinase-9 (Mmp-9) in the media of the aorta. In smooth muscle cell cultures, rh-TRAIL-induced activation of the Tak-1-JNK pathway and increase in Mmp-9 expression were inhibited by EPA. Moreover, GW9508, a specific ligand for G-protein coupled receptor (Gpr)-120/Free fatty acid receptor (Ffar)-4, mimicked the effects of EPA. The effects of EPA were abrogated by knockdown of the Gpr-120/Ffar-4 receptor gene. Our data demonstrate that the Trail-Tak-1-JNK-Mmp-9 pathway is responsible for the enhancement of AAAs in Opg-KO mice, and that EPA inhibits the Tak-1-JNK pathway by activating Gpr-120/Ffar-4, which results in the attenuation of AAA development.

Age-Associated Sirtuin 1 Reduction in Vascular Smooth Muscle Links Vascular Senescence and Inflammation to Abdominal Aortic Aneurysm.

RATIONALE: Uncontrolled growth of abdominal aortic aneurysms (AAAs) is a life-threatening vascular disease without an effective pharmaceutical treatment. AAA incidence dramatically increases with advancing age in men. However, the molecular mechanisms by which aging predisposes individuals to AAAs remain unknown. OBJECTIVE: In this study, we investigated the role of SIRT1 (Sirtuin 1), a class III histone deacetylase, in AAA formation and the underlying mechanisms linking vascular senescence and inflammation. METHODS AND RESULTS: The expression and activity of SIRT1 were significantly decreased in human AAA samples. SIRT1 in vascular smooth muscle cells was remarkably downregulated in the suprarenal aortas of aged mice, in which AAAs induced by angiotensin II infusion were significantly elevated. Moreover, vascular smooth muscle cell-specific knockout of SIRT1 accelerated angiotensin II-induced formation and rupture of AAAs and AAA-related pathological changes, whereas vascular smooth muscle cell-specific overexpression of SIRT1 suppressed angiotensin II-induced AAA formation and progression in Apoe-/- mice. Furthermore, the inhibitory effect of SIRT1 on AAA formation was also proved in a calcium chloride (CaCl2)-induced AAA model. Mechanistically, the reduction of SIRT1 was shown to increase vascular cell senescence and upregulate p21 expression, as well as enhance vascular inflammation. Notably, inhibition of p21-dependent vascular cell senescence by SIRT1 blocked angiotensin II-induced nuclear factor-κB binding on the promoter of monocyte chemoattractant protein-1 and inhibited its expression. CONCLUSIONS: These findings provide evidence that SIRT1 reduction links vascular senescence and inflammation to AAAs and that SIRT1 in vascular smooth muscle cells provides a therapeutic target for the prevention of AAA formation.