Vitamin E suppresses aortic ultrastructural alterations induced by toxic doses of monosodium glutamate / La vitamina E suprime las alteraciones ultraestructurales aórticas inducidas por dosis tóxicas de glutamato monosódico

SUMMARY: An association between certain food additives and chronic diseases is reported. Current study determined whether administering toxic doses of the food additive monosodium glutamate (MSG) into rats can induce aortopathy in association with the oxidative stress and inflammatory biomarkers upregulation and whether the effects of MSG overdose can be inhibited by vitamin E. MSG at a dose of (4 mg/kg; orally) that exceeds the average human daily consumption by 1000x was administered daily for 7 days to the rats in the model group. Whereas, rats treated with vitamin E were divided into two groups and given daily doses of MSG plus 100 mg/ kg vitamin E or MSG plus 300 mg/kg vitamin E. On the eighth day, all rats were culled. Using light and electron microscopy examinations, a profound aortic injury in the model group was observed demonstrated by damaged endothelial layer, degenerated smooth muscle cells (SMC) with vacuoles and condensed nuclei, vacuolated cytoplasm, disrupted plasma membrane, interrupted internal elastic lamina, clumped chromatin, and damaged actin and myosin filaments. Vitamin E significantly protected aorta tissue and cells as well as inhibited MSG-induced tissue malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). The highest used vitamin E dosage was more effective. Additionally, a significant correlation was observed between the aortic injury degree and tissue MDA, TNF-α, IL-6, and superoxide dismutase (SOD) levels (p=0.001). Vitamin E effectively protects against aortopathy induced by toxic doses of MSG in rats and inhibits oxidative stress and inflammation.

RESUMEN: Se reporta una asociación entre ciertos aditivos alimentarios y enfermedades crónicas. El objetivo de este estudio fue determinar si la administración de dosis tóxicas del aditivo alimentario glutamato monosódico (MSG) en ratas puede inducir aortopatía en asociación con el estrés oxidativo y la regulación positiva de los biomarcadores inflamatorios y si el efecto de una sobredosis de MSG se puede inhibir con vitamina E. Se administró MSG diariamente durante 7 días una dosis de (4 g/kg; por vía oral) que excede el consumo diario humano promedio, en 1000x a las ratas del grupo modelo. Mientras que las ratas tratadas con vitamina E se dividieron en dos grupos y se administraron dosis diarias de MSG más 100 mg/kg de vitamina E o MSG más 300 mg/kg de vitamina E. Todas las ratas fueron sacrificadas en el octavo día. Usando exámenes de microscopía óptica y electrónica, se observó una lesión aórtica profunda en el grupo modelo demostrada por una capa endotelial dañada, células musculares lisas degeneradas (SMC) con vacuolas y núcleos condensados, citoplasma vacuolado, membrana plasmática rota, lámina elástica interna interrumpida, cromatina agrupada y filamentos de actina y miosina dañados. La vitamina E protegió significativamente el tejido y las células de la aorta, además de inhibir el malondialdehído tisular (MDA) inducido por MSG, la interleucina-6 (IL-6) y el factor de necrosis tumoral alfa (TNF-α). La dosis más alta de vitamina E utilizada fue más efectiva. Además, se observó una correlación significativa entre el grado de lesión aórtica y los niveles tisulares de MDA, TNF-α, IL-6 y superóxido dismutasa (SOD) (p=0,001). La vitamina E efectivamente protege contra la aortopatía inducida por dosis tóxicas de MSG en ratas e inhibe el estrés oxidativo y la inflamación.

Relationship between blood cadmium and abdominal aortic calcification: NHANES 2013-2014.

BACKGROUND: Cadmium is a common toxic heavy metal in the environment and can cause irreversible damage to the human body. It is well established that cadmium has direct cardiovascular toxicity, but the relationship between cadmium exposure and abdominal aortic calcification (AAC) is not clear. METHODS: This was a cross-sectional study that aimed to assess the relationship between blood cadmium (B-Cd) and AAC in U.S. adults ≥ 40 years old. We obtained data from the 2013-2014 National Health and Nutrition Examination Survey. The AAC score was quantified by the Kauppila score system, whereas severe AAC was defined as an AAC score ≥ 6. We performed multivariate regressions, correlated subgroup analyses, and interaction terms to evaluate the relationship between B-Cd and AAC score and severe AAC. RESULTS: For 1530 enrolled participants, the mean AAC score was 1.52 ± 3.32, and the prevalence of severe AAC was 8.95%. Participants with higher B-Cd levels showed higher AAC scores (ß = 0.36, 95% CI: 0.03, 0.70, P = 0.0323) and an increased risk of severe AAC (OR=1.61, 95% CI: 1.01, 2.56, P = 0.0432). However, these associations were weakened after adjusting for serum cotinine to define smoking exposure. Subgroup analyses and correlated interaction terms indicated that the relationship between B-Cd and AAC was generally similar in different population settings, except for males, nonsmokers, and participants with a normal body mass index (BMI). The interaction terms indicated that smoking exposure status defined by serum cotinine interacted with the relationship between B-Cd and AAC condition (P for interaction=0.0413). CONCLUSIONS: There might be positive associations between B-Cd levels and AAC scores and the risk of severe AAC, while these associations were partially explained by smoking exposure. However, more well-designed studies are still needed to validate this relationship.

Aortic intramural haematoma associated with the use of nintedanib.

We report a 74-year-old patient who developed an acute aortic syndrome (AAS) with intramural haematoma (IMH) during treatment with nintedanib, a tyrosine kinase inhibitor. As we suspected a role for nintedanib, this was immediately interrupted. Four months later, a computed tomographic angiography (CTA) showed significant regression of the IMH. Therefore, we state that, when patients use nintedanib and develop acute chest or back pain, diagnostic work-up for AAS should be considered. Furthermore, other risk factors for AAS, such as hypertension, genetic diseases and comedication should be taken into account when prescription of medication of this class is considered.

TSP-1 (Thrombospondin-1) Deficiency Protects ApoE-/- Mice Against Leptin-Induced Atherosclerosis.

OBJECTIVE: Hyperleptinemia, hallmark of obesity, is a putative pathophysiologic trigger for atherosclerosis. We previously reported a stimulatory effect of leptin on TSP-1 (thrombospondin-1) expression, a proatherogenic matricellular protein implicated in atherogenesis. However, a causal role of TSP-1 in leptin-driven atherosclerosis remains unknown. Approach and Results: Seventeen-weeks-old ApoE-/- and TSP-1-/-/ApoE-/- double knockout mice, on normocholesterolemic diet, were treated with or without murine recombinant leptin (5 µg/g bwt, IP) once daily for 3 weeks. Using aortic root morphometry and en face lesion assay, we found that TSP-1 deletion abrogated leptin-stimulated lipid-filled lesion burden, plaque area, and collagen accumulation in aortic roots of ApoE-/- mice, shown via Oil red O, hematoxylin and eosin, and Masson trichrome staining, respectively. Immunofluorescence microscopy of aortic roots showed that TSP-1 deficiency blocked leptin-induced inflammatory and smooth muscle cell abundance as well as cellular proliferation in ApoE-/- mice. Moreover, these effects were concomitant to changes in VLDL (very low-density lipoprotein)-triglyceride and HDL (high-density lipoprotein)-cholesterol levels. Immunoblotting further revealed reduced vimentin and pCREB (phospho-cyclic AMP response element-binding protein) accompanied with augmented smooth muscle-myosin heavy chain expression in aortic vessels of leptin-treated double knockout versus leptin-treated ApoE-/-; also confirmed in aortic smooth muscle cells from the mice genotypes, incubated ± leptin in vitro. Finally, TSP-1 deletion impeded plaque burden in leptin-treated ApoE-/- on western diet, independent of plasma lipid alterations. CONCLUSIONS: The present study provides evidence for a protective effect of TSP-1 deletion on leptin-stimulated atherogenesis. Our findings suggest a regulatory role of TSP-1 on leptin-induced vascular smooth muscle cell phenotypic transition and inflammatory lesion invasion. Collectively, these results underscore TSP-1 as a potential target of leptin-induced vasculopathy.

Involvement of the toll-like receptors-2/nuclear factor-kappa B signaling pathway in atherosclerosis induced by high-fat diet and zymosan A in C57BL/6 mice.

OBJECTIVE: Accumulated evidence reported a link between the immune system, microbial infection, and the development of atherosclerosis. Excess intake of high-fat diet (HFD) increases blood lipid levels and induces inflammatory pathways whereas zymosan A (Zym), a microbial component, mediates inflammatory response through the stimulation of specific ligand of toll-like receptors (TLRs) of the immune system. The current research work was aimed to evaluate the mechanism behind atherosclerosis mediated by HFD and Zym in C57BL/6 mice. MATERIALS AND METHODS: The mice were orally fed with HFD for 30 days and Zym (80 mg/kg, single intraperitoneal injection on day 8th). On the 31st day, blood was withdrawn from overnight fasted mice by tail vein puncture and estimated for serum lipids and tumor necrosis factor-alpha (TNF-α). Animals were sacrificed, and cardiac, liver, and aortic tissues were isolated for the estimation of cardiac TLR-2, nuclear factor-kappa B (NF-ƙB); hepatic low-density lipoprotein receptors (LDLR); and base of aorta analyzed for histopathology. RESULTS: It was found that HFD and Zym administration increased arterial inflammation directly through modulation of the TLR-2/NF-ƙB pathway, thereby upregulate serum TNF-α, cardiac TLR-2, and NF-ƙB levels. Further, HFD and Zym treatment significantly increased serum lipid levels and marked decrease in LDLR protein expression in the liver when compared to normal control mice. Histopathological analysis showed the formation of atherosclerotic plaque. CONCLUSION: The study is first, to our current knowledge, to demonstrate the involvement of the TLR-2/NF-ƙB signaling pathway in atherosclerosis induced by HFD and Zym in C57BL/6 mice, resulting in increased degradation of LDLR protein, thereby, increasing the serum lipid levels.

Ziziphora clinopodioides flavonoids based on network pharmacology attenuates atherosclerosis in rats induced by high-fat emulsion combined with vitamin D3 by down-regulating VEGF/AKT/NF-κB signaling pathway.

Ziziphora clinopodioides flavonoids (ZCF) is a major bioactive total flavonoids compound isolated from Ziziphora clinopodioides Lam. It has been long used as an anti-atherosclerosis (AS) in clinics. However, anti-AS effects of ZCF have not been fully investigated. The objective of this study is to further investigate the anti-AS activities and mechanisms of ZCF in vivo. The main chemical components, action targets and signal pathways of Ziziphora clinopodioides Lam were predicted and analyzed by network pharmacology technology. The main bioactive components of Ziziphora clinopodioides Lam were identified using high performance liquid chromatography-mass spectrometry (HPLC-MS). In vivo experiments, atherosclerosis in rats induced by high-fat emulsion combined with vitamin D3 and treated with simvastatin (0.45 mg/kg/d), ZCF (6.25, 12.5, 25 g/kg/d) for 7 weeks. We found that ZCF significantly reduced blood lipid levels (TG, TC, and LDL-C), and decreased lipid deposition in the aorta and atherosclerotic lesion size, inhibited mitochondrial mem- brane potential (MMP2/9/12/13) impairment. Meanwhile, ZCF may down-regulated the levels of VEGF, AKT, NF-κB, ICAM-1 and VCAM-1 proteins, indicating ZCF may play an anti-atherosclerotic role by down-regulating the VEGF/AKT/NF-κB signaling pathway. Results from this study demonstrated that ZCF have an anti-AS ability to lower lipid concentrations and protect endothelial function, antioxidant and anti-inflammatory activity, and suggested that ZCF might be a potential therapeutic drug in the prevention of AS.

Intermittent dosing of the transforming growth factor beta receptor 1 inhibitor, BMS-986260, mitigates class-based cardiovascular toxicity in dogs but not rats.

Small-molecule inhibitors of transforming growth factor beta receptor 1 (TGFßRI) have a history of significant class-based toxicities (eg, cardiac valvulopathy) in preclinical species that have limited their development as new medicines. Nevertheless, some TGFßRI inhibitors have entered into clinical trials using intermittent-dosing schedules and exposure limits in an attempt to avoid these toxicities. This report describes the toxicity profile of the small-molecule TGFßRI inhibitor, BMS-986260, in rats and dogs. Daily oral dosing for 10 days resulted in valvulopathy and/or aortic pathology at systemic exposures that would have been targeted clinically, preventing further development with this dosing schedule. These toxicities were not observed in either species in 1-month studies using the same doses on an intermittent-dosing schedule of 3 days on and 4 days off (QDx3 once weekly). Subsequently, 3-month studies were conducted (QDx3 once weekly), and while there were no cardiovascular findings in dogs, valvulopathy and mortality occurred early in rats. The only difference compared to the 1-month study was that the rats in the 3-month study were 2 weeks younger at the start of dosing. Therefore, a follow-up 1-month study was conducted to evaluate whether the age of rats influences sensitivity to target-mediated toxicity. Using the same dosing schedule and similar doses as in the 3-month study, there was no difference in the toxicity of BMS-986260 in young (8 weeks) or adult (8 months) rats. In summary, an intermittent-dosing schedule mitigated target-based cardiovascular toxicity in dogs but did not prevent valvulopathy in rats, and thus the development of BMS-986260 was terminated.

Rooibos (Aspalathus linearis) protects against nicotineinduced vascular injury and oxidative stress in Wistar rats.

BACKGROUND: Rooibos (Aspalathus linearis) is an indigenous South African plant, traditionally used by the local population as a remedy against several ailments. More recently, rooibos was shown to exhibit potent antioxidant properties, attributed to its polyphenols. We assessed whether treatment with fermented rooibos (RF), unfermented rooibos (RUF) and melatonin (Mel), a well-documented antioxidant included for comparison, could counter the harmful vascular and pro-oxidant effects of nicotine. METHODS: Vascular function, antioxidant enzyme activity and lipid peroxidation were assessed in male adult rats treated with nicotine (5 mg/kg body weight/day) and 2% RF, 2% RUF or 4% Mel co-administration. Nitric oxide (NO) production and cell viability were measured in nicotine-exposed rat aortic endothelial cells (AECs) pre-treated with RF (0.015 mg/ml). RESULTS: Vascular studies showed that co-administration with RF or Mel exerted anti-contractile and pro-relaxation responses in aortic rings, and increased hepatic superoxide dismutase and catalase activity in nicotine-exposed animals. Co-treatment with Mel additionally decreased lipid peroxidation in nicotine-exposed rats. RUF exerted anti-contractile responses in aortic rings of nicotine-treated animals, while in nicotine-exposed AECs, RF pre-treatment increased intracellular NO levels. CONCLUSIONS: For the first time, we have shown that rooibos co-treatment exerted beneficial vascular effects in nicotine-exposed rats, and that this was associated with increased antioxidant enzyme activity.

Vehicular Particulate Matter (PM) Characteristics Impact Vascular Outcomes Following Inhalation.

Roadside proximity and exposure to mixed vehicular emissions (MVE) have been linked to adverse pulmonary and vascular outcomes. However, because of the complex nature of the contribution of particulate matter (PM) versus gases, it is difficult to decipher the precise causative factors regarding PM and the copollutant gaseous fraction. To this end, C57BL/6 and apolipoprotein E knockout mice (ApoE-/-) were exposed to either filtered air (FA), fine particulate (FP), FP+gases (FP+G), ultrafine particulate (UFP), or UFP+gases (UFP+G). Two different timeframes were employed: 1-day (acute) or 30-day (subchronic) exposures. Examined biological endpoints included aortic vasoreactivity, aortic lesion quantification, and aortic mRNA expression. Impairments in vasorelaxation were observed following acute exposure to FP+G in C57BL/6 animals and FP, UFP, and UFP+G in ApoE-/- animals. These effects were completely abrogated or markedly reduced following subchronic exposure. Aortic lesion quantification in ApoE-/- animals indicated a significant increase in atheroma size in the UFP-, FP-, and FP+G-exposed groups. Additionally, ApoE-/- mice demonstrated a significant fold increase in TNFα expression following FP+G exposure and ET-1 following UFP exposure. Interestingly, C57BL/6 aortic gene expression varied widely across exposure groups. TNFα decreased significantly following FP exposure and CCL-5 decreased in the UFP-, FP-, and FP+G-exposed groups. Conversely, ET-1, CCL-2, and CXCL-1 were all significantly upregulated in the FP+G group. These findings suggest that gas-particle interactions may play a role in vascular toxicity, but the contribution of surface area is not clear.

Tobacco cigarette smoking exacerbates aortic calcification in an early stage of myocardial infarction in a female mouse model.

Despite increased social awareness, marketing restraints, tobacco taxation, and available smoking cessation rehab programs, active and passive smoking remain a worldwide challenging epidemic and a key risk factor for cardiovascular diseases development. Although cardiovascular (CV) protection is more pronounced in women than in men due to estrogenic effects, tobacco cigarette smoking exposure seems to alter this protection by modulating estrogen actions via undefined mechanisms. Premenopausal cigarette smoking women are at higher risk of adverse CV effects than non-smokers. In this study, we investigated the impact of cigarette smoking on early CV injury after myocardial infarction (MI) in non-menopausal female mice. Aortic arch calcification, fibrosis, reactive oxygen species, and gene expression of inflammatory and calcification genes were exaggerated in mice exposed to cigarette smoke (CS). These findings suggest that aortic injury following MI, characterized by vascular smooth muscle cells transdifferentiation, calcification, inflammation, and collagen deposition but not cardiac dysfunction is exacerbated with CS exposure. The novel findings of this study highlight the importance of aortic injury on short and long-term prognosis in CS-exposed MI females. Linking those findings to estrogen alteration is probable and entails investigation.

Fenretinide treatment accelerates atherosclerosis development in apoE-deficient mice in spite of beneficial metabolic effects.

BACKGROUND AND PURPOSE: Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance, improve plasma lipid profile and reduce body fat mass. These effects, together with its ability to inhibit ceramide synthesis, suggest that fenretinide may have an anti-atherosclerotic action. EXPERIMENTAL APPROACH: To this aim, nine-week-old apoE-knockout (EKO) female mice were fed for twelve weeks a Western diet, without (control) or with (0.1% w/w) fenretinide. As a reference, wild-type (WT) mice were treated similarly. Growth and metabolic parameters were monitored throughout the study. Atherosclerosis development was evaluated in the aorta and at the aortic sinus. Blood and lymphoid organs were further characterized with thorough cytological/histological and immunocytofluorimetric analyses. KEY RESULTS: Fenretinide treatment significantly lowered body weight, glucose levels and plasma levels of total cholesterol, triglycerides, and phospholipids. In the liver, fenretinide remarkably reduced hepatic glycogenosis and steatosis driven by the Western diet. Treated spleens were abnormally enlarged, with severe follicular atrophy and massive extramedullary haematopoiesis. Severe renal hemosiderin deposition was observed in treated EKO mice. Treatment resulted in a threefold increase of total leukocytes (WT and EKO) and raised the activated/resting monocyte ratio in EKO mice. Finally, atherosclerosis development was markedly increased at the aortic arch, thoracic and abdominal aorta of fenretinide-treated mice. CONCLUSIONS AND IMPLICATIONS: We provide the first evidence that, despite beneficial metabolic effects, fenretinide treatment may enhance the development of atherosclerosis.

Intermedin1-53 Ameliorates Homocysteine-Promoted Atherosclerotic Calcification by Inhibiting Endoplasmic Reticulum Stress.

AIM: Vascular calcification (VC) is thought to be an independent predictor of cardiovascular morbidity and mortality. Intermedin1-53 (IMD) is a cardiovascular protective peptide and can inhibit vascular medial calcification in rats. In this study, we investigated the effect of IMD on atherosclerotic calcification induced by a high-fat diet plus homocysteine (Hcy) and the potential mechanisms. METHODS: ApoE-/- mice were fed a high-fat diet with Hcy in drinking water to induce atherosclerotic calcification. RESULTS: As compared to the high-fat diet alone, Hcy treatment significantly increased atherosclerotic lesion areas and the number of calcified nodules in aortic roots and was reduced by IMD infusion or 4-phenylbutyric acid (PBA) treatment. In vitro, as compared to calcifying medium alone, Hcy treatment further increased alkaline phosphatase activity, calcium content, and calcium nodule number in human aorta vascular smooth muscle cells (HA-VSMCs), all blocked by IMD or PBA pretreatment. Mechanistically, IMD or PBA significantly alleviated endoplasmic reticulum stress (ERS) activation compared with Hcy treatment. In parallel, IMD or PBA attenuated the messenger RNA levels of osteogenic markers and inflammatory cytokines in aortas and their protein levels in lesions of aortic roots. In vitro, Hcy treatment significantly increased the protein levels of osteoblast-like cell markers in primary rat VSMCs and inflammation markers in mouse peritoneal macrophages, all decreased with IMD or PBA pretreatment. Intermedin1-53 pretreatment also markedly reduced the protein levels of ERS markers in rat VSMCs and mouse peritoneal macrophages. CONCLUSIONS: Intermedin1-53 protects against Hcy-promoted atherosclerotic calcification in ApoE-/- mice by inhibiting ERS.

Acceleratory effects of ambient fine particulate matter on the development and progression of atherosclerosis in apolipoprotein E knockout mice by down-regulating CD4+CD25+Foxp3+ regulatory T cells.

OBJECTIVE: Atherosclerosis is an autoimmune inflammatory disease that is closely associated with long-term exposure to fine particulate matter (PM2.5). CD4+CD25+Foxp3+ regulatory T cells (Tregs) play a critical role in the regulation of T cell-mediated immune responses, and the depletion of CD4+CD25+Foxp3+ Tregs has been thought to play a prominent role in atherosclerosis. Therefore, we investigated the association between the CD4+CD25+Foxp3+ Tregs population and atherosclerotic development in ApoE-/- mice exposed to PM2.5. METHODS: We employed a real-world system to subject 40 ApoE-/- mice to ambient inhalation of PM2.5 (PM2.5 group, n = 20) or filtered air (FA group, n = 20) for 12 weeks. PM2.5 source apportionment, atherosclerotic lesions within aorta, lipid deposition and plaque accumulation in whole artery, serum level of inflammatory factors and lipid profiles, CD4+CD25+Foxp3+ Tregs population in splenocytes, Foxp3 protein and mRNA expressions in descending aorta and spleen were quantified, respectively. RESULTS: The daily average concentration of PM2.5 was 57.4 ± 25.6 µg/m3. Atherosclerotic lesions within aorta, lipid deposition and plaque accumulation in whole artery, serum levels of IL-6, TNF-α, TC and LDL-C in the PM2.5 group increased significantly compared to the FA group. Whereas, serum levels of IL-10 and TGF-ß, CD4+CD25+Foxp3+ Tregs population in splenocytes, Foxp3 protein and mRNA expressions in descending aorta and spleen in the PM2.5 group decreased significantly compared to the FA group. CONCLUSION: These results suggest that PM2.5 could accelerate the development of atherosclerosis in ApoE-/- mice, which is related to CD4+CD25+Foxp3+ Tregs down-regulation, as well as lipid deposition and systemic inflammation.

Elevated luteinizing hormone contributes to atherosclerosis formation by inhibiting nitric oxide synthesis via PI3K/Akt pathway.

BACKGROUND: The contentious effects of estrogen therapy on the risk of postmenopausal cardiovascular disease (CVD) indicate that this type of atherosclerosis is not solely induced by estrogen deficiency. Other sex hormones such as elevated luteinizing hormone (LH) may also affect CVD risk in this population. We therefore explored the relationship between LH and atherosclerosis in ovariectomized (OVX) female mice. METHODS: Aortic atherosclerotic lesions were assessed in OVX ApoE knock out (ApoE-/-) female mice administered with LH. Human umbilical vascular endothelial cells (HUVECs) were cultured as cell model. The influence of LH on NO release, phosphorylated endothelial nitric oxide synthase (eNOS) and Akt levels were evaluated. Immunoprecipitation and lentiviral particle transfection were applied to assess the role of Gαq on PI3K activity. RESULTS: LH increased the atherosclerotic lesion area and carotid artery intima-media thickness (IMT) in OVX ApoE-/- female mice. High levels of LH attenuated vasodilation induced by Ach and inhibited NO release from HUVECs. These effects were related to the findings that LH enhanced interaction between Gαq and p110α, which subsequently inhibited PI3K activity and suppressed the phosphorylation of Akt and eNOS. CONCLUSIONS: Elevated LH promotes atherosclerosis formation in OVX ApoE-/- female mice. This effect may be mediated by inhibiting endothelial NO synthesis via PI3K/Akt signaling pathway.

Cardiotonic Steroids Induce Vascular Fibrosis Via Pressure-Independent Mechanism in NaCl-Loaded Diabetic Rats.

Endogenous cardiotonic steroid, marinobufagenin (MBG), induces Fli1-dependent tissue fibrosis. We hypothesized that an increase in MBG initiates the development of aortic fibrosis in salt-loaded rats with type 2 diabetes mellitus (DM2) via pressure-independent mechanism. DM2 was induced by a single intraperitoneal administration of 65 mg/kg streptozotocin to neonatal (4-5 days) male Wistar rats. Eight-week-old DM2 rats received water or 1.8% NaCl (DM-NaCl) solution for 4 weeks (n = 16); half of DM-NaCl rats were treated with anti-MBG monoclonal antibody (mAb) (DM-NaCl-AB) during week 4 of salt loading; control intact rats received water (n = 8/group). Blood pressure, MBG, erythrocyte Na/K-ATPase activity, aortic weights, levels of fibrosis markers (Fli1, protein kinase Cδ, transforming growth factor-ß1, receptors of the transforming growth factor beta5, fibronectin, collagen-1), and sensitivity of the aortic explants to the vasorelaxant effect of sodium nitroprusside were assessed. No changes in systolic blood pressure were observed while erythrocyte Na/K-ATPase was inhibited by 30%, plasma MBG was doubled, and aortic markers of fibrosis became elevated in DM-NaCl rats versus control. Treatment of DM-NaCl rats with anti-MBG mAb activated Na/K-ATPase, prevented increases in aortic weights, and the levels of fibrosis markers returned to the control levels. The responsiveness of the aortic rings from DM-NaCl rats to the relaxant effect of sodium nitroprusside was reduced (half maximal effective concentration (EC50) = 29 nmol/L) versus control rings (EC50 = 7 nmol/L) and was restored by anti-MBG mAb (EC50 = 9 nmol/L). Our results suggest that in salt-loaded diabetic rats, MBG stimulates aortic collagen synthesis in a pressure-independent fashion and that 2 profibrotic mechanisms, Fli1 dependent and transforming growth factor-ß dependent, underlie its effects.

Aortic Oxidative Stress, Inflammation and DNA Damage Following Pulmonary Exposure to Cerium Oxide Nanoparticles in a Rat Model of Vascular Injury.

Pulmonary exposure to cerium oxide nanoparticles (CeO2 NPs) can occur either at the workplace, or due to their release in the environment. Inhaled CeO2 NPs are known to cross the alveolar-capillary barrier and reach various parts of the body, including the vasculature. The anticancer drug cisplatin (CP) causes vascular damage. However, the effects CeO2 NPs on vascular homeostasis in a rat model of CP-induced vascular injury remain unclear. Here, we assessed the impact and underlying mechanism of pulmonary exposure to CeO2 NPs on aorta in rats given a single intraperitoneal injection of cisplatin (CP, 6 mg/kg) to induce vascular damage. Six days later, the rats were intratracheally instilled with either CeO2 NPs (1 mg/kg) or saline (control), and various variables were studied 24 h thereafter in the aortic tissue. The concentration of reduced glutathione and the activity of catalase were significantly increased in the CP + CeO2 NPs group compared with both the CP + saline and the CeO2 NPs groups. The activity of superoxide dismutase was significantly decreased in the CP + CeO2 NPs group compared with both the CP + saline and CeO2 NPs groups. The expression of nuclear factor erythroid-derived 2-like 2 (Nrf2) by the nuclei of smooth muscles and endocardial cells assessed by immunohistochemistry was significantly augmented in CeO2 NPs versus saline, in CP + saline versus saline, and in CP + CeO2 NPs versus CeO2 NPs. Moreover, the concentrations of total nitric oxide, lipid peroxidation and 8-hydroxy-2-deoxyguanosine were significantly elevated in the CP + CeO2 NPs group compared with both the CP + saline and the CeO2 NPs groups. Similarly, compared with both the CP + saline and CeO2 NPs groups, the combination of CP and CeO2 NPs significantly elevated the concentrations of interleukin-6 and tumour necrosis factor-α. Additionally, aortic DNA damage assessed by Comet assay was significantly increased in CeO2 NPs compared with saline, and in CP + saline versus saline, and all these effects were significantly aggravated by the combination of CP and CeO2 NPs. We conclude that pulmonary exposure to CeO2 NPs aggravates vascular toxicity in animal model of vascular injury through mechanisms involving oxidative stress, Nrf2 expression, inflammation and DNA damage.

The promotion effect of novel magnetic nanoparticles on atherosclerotic plaque vulnerability in apolipoprotein E-/- mice.

Although manufactured magnetic nanoparticles (NPs) are currently used in many fields, NPs have potential toxicity on cardiovascular system especially atherosclerosis. In our previous study, we prepared novel Fe3O4 nanoparticles surface-coated with aminoguanidine (Fe3O4-AG NPs) which could remove acid dyes from aqueous solution efficiently. To understand its biocompatibility to atherosclerotic plaque vulnerability, we investigated the effects of the nanoparticles on human umbilical vein endothelial cells (HUVECs) in vitro and plaque stability in vivo. Fe3O4-AG NPs were taken up by HUVECs and induced HUVEC apoptosis. Fe3O4-AG NP injection remarkably promoted plaque vulnerability at low-dose (0.5 mg/kg) but not high-dose (5.0 mg/kg) in apolipoprotein E-/- (ApoE-/-) mice. Further study indicated that Fe3O4-AG NP-induced atherosclerotic plaque vulnerability was tightly linked to bioactivity of nitric oxide (NO). A significant decrease in NO production was induced which coincided with the inhibition of endothelial nitric oxide synthase (eNOS) activity in serum and endothelium of plaque in ApoE-/- mice injected with low-dose Fe3O4-AG NPs in vivo and HUVECs treated with low-dose Fe3O4-AG NPs in vitro. Thus, the low concentration of Fe3O4-AG NPs presented toxicity to atherosclerosis. Our results indicated that the use of Fe3O4-AG NPs to improve aqueous solution pollution should be cautious due to the potential toxicity.

Induction of human aortic myofibroblast-mediated extracellular matrix dysregulation: A potential mechanism of fluoroquinolone-associated aortopathy.

OBJECTIVES: Fluoroquinolone (FQ) antibiotics are associated with adverse aortic clinical events. We assessed human aortic myofibroblast-mediated extracellular matrix (ECM) dysregulation as a possible cellular mechanism underlying FQ-associated aortopathy. METHODS: Human aortic myofibroblasts were isolated from patients with aortopathy undergoing elective ascending aortic resection (N = 9). The capacity for extracellular matrix degradation in cells exposed to FQ was assessed by multiplex analysis of secreted matrix metalloproteinases relative to tissue inhibitors of matrix metalloproteinases (TIMPs). Direct evaluation of extracellular matrix degradation was investigated in human aortic cells using a 3-dimensional gelatin-fluorescein isothiocyanate fluorescence microgel assay. Aortic cellular collagen-1 expression following FQ exposure was determined by immunoblotting and immunofluorescent staining. Cell apoptosis, necrosis, and metabolic viability was determined by annexin-V, propidium iodide staining, and water-soluble tetrazolium salt (WST1) assay. RESULTS: FQ exposure significantly decreased aortic cell TIMP-1 (P = .004) and TIMP-2 (P = .0004) protein expression compared with vehicle control. The ratio of matrix metalloproteinase-9/TIMP-2 was increased suggesting an increased capacity for extracellular matrix degradation (P = .01). In collagen gels, we show a trend toward increased aortic myofibroblast-mediated collagen fiber degradation with FQ exposure (P = .09). Similarly, FQ exposure attenuated collagen-1 expression as assessed by immunoblotting (P = .002) and immunofluorescence (P = .02). Cell apoptosis, necrosis, and metabolic viability was not significantly influenced by FQ exposure. CONCLUSIONS: For the first time, we document a putative mechanism underlying FQ-associated aortopathy whereby decreased TIMP expression with impaired compensatory collagen-1 expression results in human aortic myofibroblast-mediated extracellular matrix dysregulation. These novel data may provide a cellular and molecular mechanism to explain the established clinical association between FQ exposure and acute aortic events.

Anti-tumor necrosis factor-α therapy increases plaque burden in a mouse model of experimental atherosclerosis.

BACKGROUND AND AIMS: Atherosclerosis is critically fueled by vascular inflammation through oxidized lipids and inflammatory cytokines such as tumor necrosis factor (TNF)-α. Genetic disruption of Tnf-α reduces atherosclerosis in experimental mouse models. However, less is known about the therapeutic potential of Tnf-α blockage by pharmacological inhibitors such as monoclonal antibodies, which are already approved for several inflammatory disorders in patients. Therefore, we investigated the effect of pharmacological TNF-α inhibition on plaque development in experimental atherosclerosis. RESULTS: 10 week old male Ldlr-/- mice were divided into 4 groups (n = 7-10) and fed a high fat, high cholesterol diet for 6 and 12 weeks. Simultaneously, the mouse-specific anti-Tnf-α monoclonal antibody CNTO5048 (CNT) or a control IgG was administered. RESULTS: CNT reduced circulating inflammatory markers without affecting body weight and glucose metabolism. Unexpectedly, CNT treatment increased plasma triglyceride levels and pro-atherogenic very-low-density lipoprotein (VLDL) cholesterol as well as plaque burden in the thoracoabdominal aorta and in the aortic root. In addition, we observed decreased smooth muscle cell content in the lesions and a trend towards reduced collagen deposition upon Tnf-α inhibition. Furthermore, inflammatory gene expression in the aortic arch was increased following Tnf-α inhibitor treatment. CONCLUSIONS: Although up to 12-week pharmacological inhibition of TNF-α in Ldlr-/- mice diminishes systemic inflammation, experimental plaque burden and vascular inflammatory gene expression are increased, while markers of plaque stability decrease. These observations may be explained by the development of a pro-atherogenic plasma lipid profile.