Cardiovascular toxic effects of nanoparticles and corresponding molecular mechanisms

Rapid advancements in nanotechnology have been integrated into various disciplines, leading to an increased prevalence of nanoparticle exposure. The widespread utilization of nanomaterials and heightened levels of particulate pollution have prompted government departments to intensify their focus on assessing the safety of nanoparticles (NPs). The cardiovascular system, crucial for maintaining human health, has emerged as vulnerable to damage from nanoparticle exposure. A mounting body of evidence indicates that interactions can occur when NPs come into contact with components of the cardiovascular system, contributing to adverse cardiovascular disease (CVD). However, the underlying molecular mechanisms driving these events remain elusive. This work provides a comprehensive review of recent advance on nanoparticle-induced adverse cardiovascular events and offers insight into the associated molecular mechanisms. Finally, the influencing factors of NPs-induced cardiovascular toxicity are discussed.

The interactions of subcellular organelles in pulmonary fibrosis induced by carbon black nanoparticles: a comprehensive review

Owing to the widespread use and improper emissions of carbon black nanoparticles (CBNPs), the adverse effects of CBNPs on human health have attracted much attention. In toxicological research, carbon black is frequently utilized as a negative control because of its low toxicity and poor solubility. However, recent studies have indicated that inhalation exposure to CBNPs could be a risk factor for severe and prolonged pulmonary inflammation and fibrosis. At present, the pathogenesis of pulmonary fibrosis induced by CBNPs is still not fully elucidated, but it is known that with small particle size and large surface area, CBNPs are more easily ingested by cells, leading to organelle damage and abnormal interactions between organelles. Damaged organelle and abnormal organelles interactions lead to cell structure and function disorders, which is one of the important factors in the development and occurrence of various diseases, including pulmonary fibrosis. This review offers a comprehensive analysis of organelle structure, function, and interaction mechanisms, while also summarizing the research advancements in organelles and organelle interactions in CBNPs-induced pulmonary fibrosis.

Impact of black soot emissions on public health in Niger Delta, Nigeria: understanding the severity of the problem

Rivers State, Niger Delta, Nigeria often referred to as the 'treasure bed of the nation' is the seat of crude oil production activities with the accompanying environmental degradation. The severity of the environmental pollution and contaminated air quality took a new turn for the worse in November 2016, when the residents of Port Harcourt city, Rivers State, a major oil producing State experienced for the first time, aerosol deposition of plumes of black soot. This systematic review paper is aimed at quantifying the severity of this public health challenge. Using appropriate search words, the following databases SCOPUS, PUBMED, Google Scholar, and AJOL were searched from 1990 to 2022 to enable comparative analyses of data before and after the emergence of black soot deposition. Air-related morbidities and mortalities such as cerebrospinal meningitis (CSM), chronic bronchitis, measles, pertussis, hemoptysis, cough, pulmonary tuberculosis, pneumonia, and upper respiratory tract infection (URTI), pneumonia, eye irritation, conjunctivitis, traumatic skin outgrowth, cancers, cardiovascular diseases, and child deformities were compared with levels of air pollutants and particulate matter. The results showed that Port Harcourt city's ambient air quality data were above the standard National Ambient Air Quality data and that of other regulatory agencies having higher levels of both inorganic and organic pollutants. There were significant relationships between air pollutants concentration with morbidities. These correlations were significant in the period covering 2016-2022. Consequently, it is concluded that the black soot emissions in Port Harcourt city, Nigeria has worsened the public health situation in the city.

Atmospheric elemental carbon pollution and its regional health disparities in China

Previous studies have reported that atmospheric elemental carbon (EC) may pose potentially elevated toxicity when compared to total ambient fine particulate matter (PM2.5). However, most research on EC has been conducted in the US and Europe, whereas China experiences significantly higher EC pollution levels. Investigating the health impact of EC exposure in China presents considerable challenges due to the absence of a monitoring network to document long-term EC levels. Despite extensive studies on total PM2.5 in China over the past decade and a significant decrease in its concentration, changes in EC levels and the associated mortality burden remain largely unknown. In our study, we employed a combination of satellite remote sensing, available ground observations, machine learning techniques, and atmospheric big data to predict ground EC concentrations across China for the period 2005-2018, achieving a spatial resolution of 10 km. Our findings reveal that the national average annual mean EC concentration has remained relatively stable since 2005, even as total PM2.5 levels have substantially decreased. Furthermore, we calculated the all-cause non-accidental deaths attributed to long-term EC exposure in China using baseline mortality data and pooled mortality risk from a cohort study. This analysis unveiled significant regional disparities in the mortality burden resulting from long-term EC exposure in China. These variations can be attributed to varying levels of effectiveness in EC regulations across different regions. Specifically, our study highlights that these regulations have been effective in mitigating EC-related health risks in first-tier cities. However, in regions characterized by a high concentration of coal-power plants and industrial facilities, additional efforts are necessary to control emissions. This observation underscores the importance of tailoring environmental policies and interventions to address the specific challenges posed by varying emission sources and regional contexts.

Impact of surface chemistry of ultrasmall superparamagnetic iron oxide nanoparticles on protein corona formation and endothelial cell uptake, toxicity, and barrier function

Ultrasmall superparamagnetic iron oxide nanoparticles (USPION) have been investigated for biomedical applications, including novel contrast agents, magnetic tracers for tumor imaging, targeted drug delivery vehicles, and magneto-mechanical actuators for hyperthermia and thrombolysis. Despite significant progress, recent clinical reports have raised concerns regarding USPION safety related to endothelial cell dysfunction; however, there is limited information on factors contributing to these clinical responses. The influence of USPION surface chemistry on nanoparticle interactions with proteins may impact endothelial cell function leading to adverse responses. Therefore, the goal of this study was to assess the effects of carboxyl-functionalized USPION (CU) or amine-functionalized USPION (AU) (∼30 nm diameter) on biological responses in human coronary artery endothelial cells. Increased protein adsorption was observed for AU compared to CU after exposure to serum proteins. Exposure to CU, but not AU, resulted in a concentration-dependent decrease in cell viability and perinuclear accumulation inside cytoplasmic vesicles. Internalization of CU was correlated with endothelial cell functional changes under non-cytotoxic conditions, as evidenced by a marked decreased expression of endothelial-specific adhesion proteins (e.g., VE-cadherin and PECAM-1) and increased endothelial permeability. Evaluation of downstream signaling indicated endothelial permeability is associated with actin cytoskeleton remodeling, possibly elicited by intracellular events involving reactive oxygen species, calcium ions, and the nanoparticle cellular uptake pathway. This study demonstrated that USPION surface chemistry significantly impacts protein adsorption and endothelial cell uptake, viability, and barrier function. This information will advance the current toxicological profile of USPION and improve development, safety assessment, and clinical outcomes of USPION-enabled medical products.

Elevated intraocular pressure induces neuron-specific β-III-tubulin expression in non-neuronal vascular cells

PURPOSE

Pathological alterations within optic nerve axons and progressive loss of the parental retinal ganglion cell (RGC) bodies are characteristics of glaucomatous neuropathy. Abnormally elevated intraocular pressure (IOP) is thought to be the major risk factor for most forms of glaucomatous changes, while lowering of the IOP is the mainstream of treatment. However, the pathophysiological mechanisms involved in neurodegenerative changes are poorly understood. It remains still a matter of debate whether elevated IOP harms the neurons directly or indirectly through alterations in the retinal vascularization.

METHODS

We analysed morphological and molecular changes within the retina exposed to elevated IOP in an animal model of glaucoma in vivo, in retinal explants and in cultured dissociated retinal cells each incubated under elevated air pressure in vitro, imitating elevated IOP.

RESULTS

Although ß-III-tubulin expressing RGCs decreased within the course of the disease, total amount of ß-III-tubulin protein within the retina increased, leading to the assumption that other cells than RGCs abnormally express ß-III-tubulin due to elevated IOP. Surprisingly, we found that β-III-tubulin, a marker developmentally regulated and specifically expressed in neurons under normal conditions, was strongly up-regulated in desmin-, PDGFR-β- and α-SMA-positive pericytes as well as in endothelin-1-positive endothelial cells both in vivo under elevated IOP and in vitro under elevated culture atmosphere pressure that simulated IOP elevation. Beta-III-tubulin-driven signalling pathways (ERK 1/2, pERK1/2 and cdc42/Rac) were also regulated.

CONCLUSION

The unprecedented regulation of neuron-specific β-III-tubulin in pericytes and endothelial cells is likely associated with a role of the retinal vasculature in the IOP-induced development and manifestation of glaucomatous degenerative optic nerve response.

Telomere length and genotoxicity in the lung of rats following intragastric exposure to food-grade titanium dioxide and vegetable carbon particles

Vegetable carbon (E153) and titanium dioxide (E171) are widely used as black and white food colour additives. The aim of this study was to assess gastrointestinal tight junction and systemic genotoxic effects in rats following exposure to E153 and E171 for 10 weeks by oral gavage once a week. The expression of tight junction proteins was assessed in intestinal tissues. Levels of DNA strand breaks, oxidatively damaged DNA and telomere length were assessed in secondary organs. Hydrodynamic suspensions of E153 and E173 indicated mean particles sizes of 230 and 270 nm, respectively, and only E153 gave rise to intracellular production of reactive oxygen species in colon epithelial (Caco-2) cells. Rats exposed to E153 (6.4 mg/kg/week) or E171 (500 mg/kg/week) had decreased gene expression of the tight junction protein TJP1 (P < 0.05). E153 (6.4 mg/kg/week) also decreased OCLN (P < 0.05) in the colon and occludin protein expression in the small intestine (P < 0.05). Furthermore, E153 or E171 exposed rats had shorter telomeres in the lung (P < 0.05). Plasma from particle-exposed rats also produced telomere shortening in cultured lung epithelial cells. There were unaltered levels of oxidatively damaged DNA in the liver and lung and no changes in the DNA repair activity of oxidatively damaged DNA in the lung. Altogether, these results indicate that intragastric exposure to E153 and E171 is associated with reduced tight junction protein expression in the intestinal barrier and telomere length shortening in the lung in rats.

Caloric restriction induces H2O2 formation as a trigger of AMPK-eNOS-NO pathway in obese rats: Role for CAMKII

Caloric restriction (CR) improves endothelial function through the upregulation of adenosine monophosphate-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). Moreover, hydrogen peroxide (H₂O₂) is upregulated in yeast subjected to CR. Our aim was to assess if mild short-term CR increases vascular H₂O₂ formation as a link with AMPK and eNOS activation. Twelve-week old Zucker obese (fa/fa) and control Zucker lean male rats were fed a standard chow either ad libitum (AL, n=10) or with a 20% CR (CR, n=10) for two weeks. CR significantly improved relaxation to ACh in fa/fa rats because of an enhanced endogenous production of H₂O₂ in aortic rings (H₂O₂ levels _fa/faAL=0.5 ± 0.05 nmol/mg vs. H₂O₂ levels _fa/faCR=0.76 ± 0.07 nmol/mg protein; p<0.05). Expression of mitochondrial superoxide dismutase (Mn-SOD) and total SOD activity were increased in aorta from fa/fa animals after CR. In cultured aortic endothelial cells, serum deprivation or 2-deoxy-d-glucose induced a significant increase in: i) superoxide anion and H₂O₂ levels, ii) p-AMPK/AMPK and p-eNOS/eNOS expression and iii) nitric oxide levels. This effect was reduced by catalase and strongly inhibited by Ca²⁺/calmodulin-dependent kinase II (CamkII) silencing. In conclusion, we propose that mild short-term CR might be a trigger of mechanisms aimed at protecting the vascular wall by the increase of H₂O₂, which then activates AMPK and nitric oxide release, thus improving endothelium-dependent relaxation. In addition, we demonstrate that CAMKII plays a key role in mediating CR-induced AMPK activation through H₂O₂ increase.

Oxymatrine ameliorates diabetes-induced aortic endothelial dysfunction via the regulation of eNOS and NOX4

AIM

Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait (the Chinese herb Kushen) and exhibits diverse pharmacological actions. In this study, we investigated the effects of OMT on diabetes-associated aortic endothelial dysfunction in a rat model of diabetes and its mechanisms.

METHODS

Male Sprague-Dawley rats were randomly divided into five groups: control, diabetic rats, diabetic rats treated with OMT (60, 120 mg/kg per day, by gavage), and diabetic rats treated with metformin (20 mg/kg per day, by gavage). The serum fasting blood glucose, insulin, total cholesterol, triglyceride, and nitric oxide (NO) levels were determined with commercial kits. Biochemical indices reflecting oxidative stress, such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were analyzed with commercial kits. Mitochondrial reactive oxygen species 2',7'-dichlorofluorescein diacetate (DCFH-DA) was measured by fluorescence microscopy. Histological analyses were conducted to observe morphological changes. Western blot analysis was applied to detect the expression levels of eNOS and NOX4. Reverse transcription polymerase chain reaction was used to detect the expressions of eNOS and NOX4 messenger RNA (mRNA).

RESULTS

The diabetic rats exhibited markedly reduced body weight and increased plasma glucose levels. Moreover, the diabetic rats showed oxidative stress (significantly increased MDA and decreased SOD, CAT, GSH-Px, and serum NO levels). Hyperglycemia caused significant endothelial injury and dysfunction, including vasodilative and histologic changes in the diabetic rats. The expressions of phospho-eNOS protein and mRNA were significantly decreased, while the NOX4 protein expression was increased in the aortas of the diabetic rats. All of these diabetes-induced effects were reversed by OMT in the diabetic rats.

CONCLUSION

The OMT treatment ameliorates diabetic endothelial dysfunction through enhanced NO bioavailability by upregulating eNOS expression and downregulating expression of NOX4.

Assessing the in vitro and in vivo toxicity of ultrafine carbon black to mouse liver

The increasing presence of nanomaterials in commercial products makes large quantities of nanoparticles reach the environment intentionally or accidentally. Their ability to be cleared from lung to stomach and then translocate into blood circulation suggests they may cause effects on the organs and cells of the organism. In this study, we characterized the dispersity of UFCB (ultrafine carbon black, FW200) in the complete medium and investigated the toxicity of FW200 to mouse hepatocytes and the liver both in vitro and in vivo. FW200 dispersed homogeneously in the complete medium with an average size at around 100 nm. In vitro, FW200 induced apparent cytotoxicity in the hepatocytes with the level of oxidative stress, apoptosis and the viability of hepatocytes changed by approximately 30%. The intracellular catalase (CAT) activity was stimulated by FW200 to a higher level than the control group. In vivo, the 7-week mice were exposed to FW200 (10 mg/kg body weight) by oral administration for six days. The liver was collected and used for histopathological analysis. In our findings, the 13 nm carbon black nanoparticle was proved to induce acute inflammation and apoptosis in the liver. The particles were also proved to have a damage to central veins and architecture of the hepatocytes. These findings suggest that the carbon black nanoparticle could cause a negative effect at both the cellular and organism level and unearthed the potential effects of carbon black nanoparticles on animals and human.

Recent advances in nanotechnology for the treatment of metabolic syndrome

Metabolic syndrome is a main clinical challenge of global health which is growing universally. It would be resulted from over-consumption of energy, increased obesity, and lack of movement during life. The metabolic syndrome causes a five-fold increase in the risk of type 2 diabetes mellitus and a double increase in the risk of rising cardiovascular disease over the next 5-10 years. Based on this, more attention has been drawn to the diagnosis and treatment options of this disease. Nanotechnology is one of the preferred methods for improving this disease. This way is a natural development in many health domains, including synthetic and nanostructures. The use of nanoparticles with the purpose of increase the effectiveness of treatment, decrease the side effects and the amount of drug usage, through their small size, permeability and maintenance strength lead to their absorption by target organs. Meanwhile, different nanoparticles with consumption values and particle size have been investigated.

Vasomotor function in rat arteries after ex vivo and intragastric exposure to food-grade titanium dioxide and vegetable carbon particles

Background

Humans are continuously exposed to particles in the gastrointestinal tract. Exposure may occur directly through ingestion of particles via food or indirectly by removal of inhaled material from the airways by the mucociliary clearance system. We examined the effects of food-grade particle exposure on vasomotor function and systemic oxidative stress in an ex vivo study and intragastrically exposed rats.

Methods

In an ex vivo study, aorta rings from naïve Sprague-Dawley rats were exposed for 30 min to food-grade TiO₂ (E171), benchmark TiO₂ (Aeroxide P25), food-grade vegetable carbon (E153) or benchmark carbon black (Printex 90). Subsequently, the vasomotor function was assessed in wire myographs. In an in vivo study, lean Zucker rats were exposed intragastrically once a week for 10 weeks to vehicle, E171 or E153. Doses were comparable to human daily intake. Vasomotor function in the coronary arteries and aorta was assessed using wire myographs. Tetrahydrobiopterin, ascorbate, malondialdehyde and asymmetric dimethylarginine were measured in blood as markers of oxidative stress and vascular function.

Results

Direct exposure of E171 to aorta rings ex vivo increased the acetylcholine-induced vasorelaxation and 5-hydroxytryptamine-induced vasocontraction. E153 only increased acetylcholine-induced vasorelaxation, and Printex 90 increased the 5-hydroxytryptamine-induced vasocontraction, whereas Aeroxide P25 did not affect the vasomotor function. In vivo exposure showed similar results as ex vivo exposure; increased acetylcholine-induced vasorelaxation in coronary artery segments of E153 and E171 exposed rats, whereas E171 exposure altered 5-hydroxytryptamine-induced vasocontraction in distal coronary artery segments. Plasma levels of markers of oxidative stress and vascular function showed no differences between groups.

Conclusion

Gastrointestinal tract exposure to E171 and E153 was associated with modest albeit statistically significant alterations in the vasocontraction and vasorelaxation responses. Direct particle exposure to aorta rings elicited a similar type of response. The vasomotor responses were not related to biomarkers of systemic oxidative stress.

The Toxicological Mechanisms of Environmental Soot (Black Carbon) and Carbon Black: Focus on Oxidative Stress and Inflammatory Pathways

The environmental soot and carbon blacks (CBs) cause many diseases in humans, but their underlying mechanisms of toxicity are still poorly understood. Both are formed after the incomplete combustion of hydrocarbons but differ in their constituents and percent carbon contents. For the first time, “Sir Percival Pott” described soot as a carcinogen, which was subsequently confirmed by many others. The existing data suggest three main types of diseases due to soot and CB exposures: cancer, respiratory diseases, and cardiovascular dysfunctions. Experimental models revealed the involvement of oxidative stress, DNA methylation, formation of DNA adducts, and Aryl hydrocarbon receptor activation as the key mechanisms of soot- and CB-induced cancers. Metals including Si, Fe, Mn, Ti, and Co in soot also contribute in the reactive oxygen species (ROS)-mediated DNA damage. Mechanistically, ROS-induced DNA damage is further enhanced by eosinophils and neutrophils via halide (Cl⁻ and Br⁻) dependent DNA adducts formation. The activation of pulmonary dendritic cells, T helper type 2 cells, and mast cells is crucial mediators in the pathology of soot- or CB-induced respiratory disease. Polyunsaturated fatty acids (PUFAs) were also found to modulate T cells functions in respiratory diseases. Particularly, telomerase reverse transcriptase was found to play the critical role in soot- and CB-induced cardiovascular dysfunctions. In this review, we propose integrated mechanisms of soot- and CB-induced toxicity emphasizing the role of inflammatory mediators and oxidative stress. We also suggest use of antioxidants and PUFAs as protective strategies against soot- and CB-induced disorders.

Inflammation and Vascular Effects after Repeated Intratracheal Instillations of Carbon Black and Lipopolysaccharide

Inflammation and oxidative stress are considered the main drivers of vasomotor dysfunction and progression of atherosclerosis after inhalation of particulate matter. In addition, new studies have shown that particle exposure can induce the level of bioactive mediators in serum, driving vascular- and systemic toxicity. We aimed to investigate if pulmonary inflammation would accelerate nanoparticle-induced atherosclerotic plaque progression in Apolipoprotein E knockout (ApoE^-/-) mice. ApoE^-/- mice were exposed to vehicle, 8.53 or 25.6 μg nanosized carbon black (CB) alone or spiked with LPS (0.2 μg/mouse/exposure; once a week for 10 weeks). Inflammation was determined by counting cells in bronchoalveolar lavage fluid. Serum Amyloid A3 (Saa3) expression and glutathione status were determined in lung tissue. Plaque progression was assessed in the aorta and the brachiocephalic artery. The effect of vasoactive mediators in plasma of exposed ApoE^-/- mice was assessed in aorta rings isolated from naïve C57BL/6 mice. Pulmonary exposure to CB and/or LPS resulted in pulmonary inflammation with a robust influx of neutrophils. The CB exposure did not promote plaque progression in aorta or BCA. Incubation with 0.5% plasma extracted from CB-exposed ApoE^-/- mice caused vasoconstriction in aorta rings isolated from naïve mice; this effect was abolished by the treatment with the serotonin receptor antagonist Ketanserin. In conclusion, repeated pulmonary exposure to nanosized CB and LPS caused lung inflammation without progression of atherosclerosis in ApoE^-/- mice. Nevertheless, plasma extracted from mice exposed to nanosized CB induced vasoconstriction in aortas of naïve wild-type mice, an effect possibly related to increased plasma serotonin.

Bio-effect of nanoparticles in the cardiovascular system

Nanoparticles (NPs; < 100 nm) are increasingly being applied in various fields due to their unique physicochemical properties. The increase in human exposure to NPs has raised concerns regarding their health and safety profiles. The potential correlation between NP exposure and several cardiovascular (CV) events has been demonstrated. The aim of this review is to provide a comprehensive evaluation of the current knowledge regarding the bio-toxic impacts of titanium oxide, silver, silica, carbon black, carbon nanotube, and zinc oxide NPs exposure on the CV system in terms of in vivo and in vitro experiments, which is not fully understood presently. Moreover, the potential toxic mechanisms of NPs in the CV system that are still being questioned are elaborately discussed, and the underlying capacity of NPs used in medicine for CV events are summarized. It will be an important instrument to extrapolate relevant data for human CV risk evaluation and management. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2881-2897, 2016.

MMP-9-Dependent Serum-Borne Bioactivity Caused by Multiwalled Carbon Nanotube Exposure Induces Vascular Dysfunction via the CD36 Scavenger Receptor

Inhalation of multiwalled carbon nanotubes (MWCNT) causes systemic effects including vascular inflammation, endothelial dysfunction, and acute phase protein expression. MWCNTs translocate only minimally beyond the lungs, thus cardiovascular effects thereof may be caused by generation of secondary biomolecular factors from MWCNT-pulmonary interactions that spill over into the systemic circulation. Therefore, we hypothesized that induced matrix metalloproteinase-9 (MMP-9) is a generator of factors that, in turn, drive vascular effects through ligand-receptor interactions with the multiligand pattern recognition receptor, CD36. To test this, wildtype (WT; C57BL/6) and MMP-9(-/-)mice were exposed to varying doses (10 or 40 µg) of MWCNTs via oropharyngeal aspiration and serum was collected at 4 and 24 h postexposure. Endothelial cells treated with serum from MWCNT-exposed WT mice exhibited significantly reduced nitric oxide (NO) generation, as measured by electron paramagnetic resonance, an effect that was independent of NO scavenging. Serum from MWCNT-exposed WT mice inhibited acetylcholine (ACh)-mediated relaxation of aortic rings at both time points. Absence of CD36 on the aortic rings (obtained from CD36-deficient mice) abolished the serum-induced impairment of vasorelaxation. MWCNT exposure induced MMP-9 protein levels in both bronchoalveolar lavage and whole lung lysates. Serum from MMP-9(-/-)mice exposed to MWCNT did not diminish the magnitude of vasorelaxation in naïve WT aortic rings, although a modest right shift of the ACh dose-response curve was observed in both MWCNT dose groups relative to controls. In conclusion, pulmonary exposure to MWCNT leads to elevated MMP-9 levels and MMP-9-dependent generation of circulating bioactive factors that promote endothelial dysfunction and decreased NO bioavailability via interaction with vascular CD36.

Carbon nanoparticle induced cytotoxicity in human mesenchymal stem cells through upregulation of TNF3, NFKBIA and BCL2L1 genes

Carbon based nanomaterials, including carbon nanotubes, graphene, nanodiamond and carbon nanoparticles, have emerged as potential candidates for a wide variety of applications because of their unusual electrical, mechanical, thermal and optical properties. However, our understanding of how increased usage of carbon based nanomaterials could lead to harmful effects in humans and other biological systems is inadequate. Our present investigation is focused on the cellular toxicity of carbon nanoparticles (CNPs) on human mesenchymal stem cells (hMSCs). Following exposure to CNPs, cell viability, nuclear morphological changes, apoptosis and cell cycle progression were monitored. Furthermore, the expression of genes involved in both cell death (e.g., P53, TNF3, CDKN1A, TNFRSF1A, TNFSF10, NFKBIA, BCL2L1) and cell cycle regulation (e.g., PCNA, EGR1, E2F1, CCNG1, CCND1, CCNC, CYCD3) were assessed using qPCR. Our results indicated that CNPs reduce cell viability and cause chromatin condensation and DNA fragmentation. Cell cycle analysis indicated that CNPs affect the cell cycle progression. However, the gene expression measurements confirmed that CNPs significantly upregulated the P53, TNF3, CDKNIA, and NFKBIA genes and downregulated the EGR1 gene in hMSCs. Our findings suggest that CNPs reduce cell viability by disrupting the expression of cell death genes in human mesenchymal stem cell (hMSC). The results of this investigation revealed that CNPs exhibited moderate toxicity on hMSCs.

The biological effects upon the cardiovascular system consequent to exposure to particulates of less than 500 nm in size

CONTEXT

Ultrafine particulate matter contribution to cardiovascular disease is not known and not regulated. PM up to 500 nm are abundant in urban air and alveolar deposition is significant.

OBJECTIVE

Effects beyond the alveolar barrier within the body or in vitro tissues exposed to particles <500 nm.

METHODS AND RESULTS

DATABASES

MEDLINE; Ovid-MEDLINE PREM; Web of Science; PubMed (SciGlobe). 127 articles. Results in tables: "subject type exposed", "exposure type", "technique".

CONCLUSION

Heart rate, vasoactivity, atherosclerotic advancement, oxidative stress, coagulability, inflammatory changes are affected. Production of reactive oxygen species is a useful target to limit outcomes associated with UFP exposure.

Monocyte adhesion induced by multi-walled carbon nanotubes and palmitic acid in endothelial cells and alveolar-endothelial co-cultures

Free palmitic acid (PA) is a potential pro-atherogenic stimulus that may aggravate particle-mediated cardiovascular health effects. We hypothesized that the presence of PA can aggravate oxidative stress and endothelial activation induced by multi-walled carbon nanotube (MWCNT) exposure in vitro. We investigated the interaction between direct exposure to MWCNTs and PA on THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs), as well as on indirect exposure in an alveolar-endothelial co-culture model with A549 cells and THP-1-derived macrophages exposed in inserts and the effect measured in the lower chamber on HUVECs and THP-1 cells. The exposure to MWCNTs, including a short (NM400) and long (NM402) type of entangled fibers, was associated with elevated levels of reactive oxygen species as well as a decrease in the intracellular glutathione concentration in HUVEC and A549 monocultures. Both effects were found to be independent of the presence of PA. MWCNT exposure significantly increased THP-1 monocyte adhesion to HUVECs, and co-exposure to PA aggravated the NM400-mediated adhesion but decreased the NM402-mediated adhesion. For the co-cultures, the exposure of A549 cells did not promote THP-1 adhesion to HUVECs in the lower chamber. When THP-1 macrophages were present on the cell culture inserts, there was a modest increase in the adhesion and an increase in interleukin-6 and interleukin-8 levels in the lower chamber whereas no tumor necrosis factor was detected. Overall, this study showed that direct exposure of HUVECs to MWCNTs was associated with oxidative stress and monocyte adhesion and the presence of PA increased the adhesion when exposed to NM400.

Hepatic oxidative stress, genotoxicity and vascular dysfunction in lean or obese Zucker rats

Metabolic syndrome is associated with increased risk of cardiovascular disease, which could be related to oxidative stress. Here, we investigated the associations between hepatic oxidative stress and vascular function in pressurized mesenteric arteries from lean and obese Zucker rats at 14, 24 and 37 weeks of age. Obese Zucker rats had more hepatic fat accumulation than their lean counterparts. Nevertheless, the obese rats had unaltered age-related level of hepatic oxidatively damaged DNA in terms of formamidopyrimidine DNA glycosylase (FPG) or human oxoguanine DNA glycosylase (hOGG1) sensitive sites as measured by the comet assay. There were decreasing levels of oxidatively damaged DNA with age in the liver of lean rats, which occurred concurrently with increased expression of Ogg1. The 37 week old lean rats also had higher expression level of Hmox1 and elevated levels of DNA strand breaks in the liver. Still, both strain of rats had increased protein level of HMOX-1 in the liver at 37 weeks. The external and lumen diameters of mesenteric arteries increased with age in obese Zucker rats with no change in media cross-sectional area, indicating outward re-modelling without hypertrophy of the vascular wall. There was increased maximal response to acetylcholine-mediated endothelium-dependent vasodilatation in both strains of rats. Collectively, the results indicate that obese Zucker rats only displayed a modest mesenteric vascular dysfunction, with no increase in hepatic oxidative stress-generated DNA damage despite substantial hepatic steatosis.

Mild caloric restriction reduces blood pressure and activates endothelial AMPK-PI3K-Akt-eNOS pathway in obese Zucker rats

Genetic obesity models exhibit endothelial dysfunction associated to adenosine monophosphate-activated protein kinase (AMPK) dysregulation. This study aims to assess if mild short-term caloric restriction (CR) restores endothelial AMPK activity leading to an improvement in endothelial function. Twelve-week old Zucker lean and obese (fa/fa) male rats had access to standard chow either ad libitum (AL, n=8) or 80% of AL (CR, n=8) for two weeks. Systolic blood pressure was significantly higher in fa/fa AL rats versus lean AL animals, but was normalized by CR. Endothelium-dependent relaxation to acetylcholine (ACh, 10(-9) to 10(-4) M) was reduced in fa/fa AL compared to control lean AL rats (p<0.001), and restored by CR. The AMPK activator AICAR (10(-5) to 8·10(-3) M) elicited a lower relaxation in fa/fa AL rings that was normalized by CR (p<0.001). Inhibition of PI3K (wortmannin, 10(-7) M), Akt (triciribine, 10(-5) M), or eNOS (L-NAME, 10(-4) M) markedly reduced AICAR-induced relaxation in lean AL, but not in fa/fa AL rats. These inhibitions were restored by CR in Zucker fa/fa rings. These data show that mild short-term CR improves endothelial function and lowers blood pressure in obesity due to the activation of the AMPK-PI3K-Akt-eNOS pathway.