Effects of fluorides on apoptosis and activation of human umbilical vein endothelial cells

Impact of Fluoride Exposure on Rat Placenta: Foetal/Placental Morphometric Alterations and Decreased Placental Vascular Density

Inorganic fluoride is a geogenic and anthropogenic contaminant widely distributed in the environment and commonly identified in contaminated groundwater. There is limited information on the effect of fluoride exposure on pregnancy. The aim of this study was to evaluate possible placental alterations of fluoride exposure in a rat model simulating preconception and pregnancy exposure conditions in endemic areas. Fluoride exposure was administered orally to foetuses of dams exposed to 2.5 and 5 mg fluoride/kg/d. Foetal weight, height, foetal/placental weight ratio, placental zone thickness, levels of malondialdehyde (MDA) and vascular endothelial growth factor-A (VEGF-A) and vascular density in placental tissue were evaluated. The results showed a nonlinear relationship between these outcomes and the dose of fluoride exposure. In addition, a significant increase in the fluoride concentration in placental tissue was observed. The group that was exposed to 2.5 mg fluoride/kg/d had a greater increase in both MDA levels and VEGF-A levels than the higher dose group. A significant increase in the thickness of the placental zones and a decrease in the vascular density of the labyrinth zone area were also observed in the fluoride-exposed groups. In conclusion, the data obtained demonstrate that fluoride exposure results in morpho-structural alterations in the placenta and that non-monotonic changes in MDA, VEGF-A levels and placental foetal weight ratio were at environmentally relevant concentrations.

Evaluation of vascular and kidney injury biomarkers in Mexican children exposed to inorganic fluoride

Exposure to inorganic fluoride (F) has been implicated in cardiovascular and kidney dysfunction mainly in adult populations. However, limited epidemiological information from susceptible populations, such as children, is available. In this study we evaluated the relationship of F exposure with some vascular and kidney injury biomarkers in children. A cross-sectional study was conducted in 374 Mexican schoolchildren. Dental fluorosis and F concentrations in the water and urine were evaluated. The glomerular filtration rate (eGFR) and the urinary concentrations of kidney injury molecule 1 (KIM-1) and cystatin-C (uCys-C) were examined to assess kidney injury. The carotid intima media thickness (cIMT) and serum concentrations of vascular adhesion molecule 1 (VCAM-1), intracellular adhesion molecule 1 (ICAM-1), endothelin 1(ET-1) and cystatin-C (sCys-C) were measured to assess vascular alterations. High proportions of children exposed to F were observed (79.7% above 1.2 ppm F in urine) even in the low water F exposure regions, which suggested additional sources of F exposure. In robust multiple linear regression models, urinary F was positively associated with eGFR (β = 1.3, p = 0.015), uCys-C (β = -8.5, p = 0.043), VCAM-1 (β = 111.1, p = 0.019), ICAM-1 (β = 57, p = 0.032) and cIMT (β = 0.01, p = 0.032). An inverse association was observed with uCys-C (β = -8.5, p = 0.043) and sCys-C (β = -9.6, p = 0.021), and no significant associations with ET-1 (β = 0.069, p = 0.074) and KIM-1 (β = 29.1, p = 0.212) were found. Our findings revealed inconclusive results regarding F exposure and kidney injury. However, these results suggest that F exposure is related to early vascular alterations, which may increase the susceptibility of cardiovascular diseases in adult life.

In vitro systems toxicology-based assessment of the potential modified risk tobacco product CHTP 1.2 for vascular inflammation- and cytotoxicity-associated mechanisms promoting adhesion of monocytic cells to human coronary arterial endothelial cells

Cigarette smoking causes cardiovascular diseases. Heating tobacco instead of burning it reduces the amount of toxic compounds in the aerosol and may exert a reduced impact on health compared with cigarette smoke. Aqueous extract from the aerosol of a potential modified risk tobacco product, the Carbon Heated Tobacco Product (CHTP) 1.2, was compared in vitro with aqueous extract from the smoke of a 3R4F reference cigarette for its impact on the adhesion of monocytic cells to artery endothelial cells. Human coronary artery endothelial cells (HCAEC) were treated for 4 h with conditioned media from human monocytic Mono Mac 6 (MM6) cells exposed to CHTP1.2 or 3R4F extracts for 2 h or directly with those extracts freshly generated. In vitro monocyte-endothelial cell adhesion was measured concomitantly with inflammatory, oxidative stress, cytotoxicity, and death markers. Furthermore, transcriptomics analyses enabled to quantify the level of perturbation in HCAECs, and provide biological interpretation for the underlying molecular changes following exposure to 3R4F or CHTP1.2 extract. Our systems toxicology study demonstrated that approximately 10-15-fold higher concentrations of the CHTP 1.2 aerosol extract were needed to elicit similar effects as the 3R4F smoke extract on cardiovascular disease-relevant inflammation and cytotoxicity-related mechanisms and markers investigated in vitro.

Genes and gene networks involved in sodium fluoride-elicited cell death accompanying endoplasmic reticulum stress in oral epithelial cells

Here, to understand the molecular mechanisms underlying cell death induced by sodium fluoride (NaF), we analyzed gene expression patterns in rat oral epithelial ROE2 cells exposed to NaF using global-scale microarrays and bioinformatics tools. A relatively high concentration of NaF (2 mM) induced cell death concomitant with decreases in mitochondrial membrane potential, chromatin condensation and caspase-3 activation. Using 980 probe sets, we identified 432 up-regulated and 548 down-regulated genes, that were differentially expressed by >2.5-fold in the cells treated with 2 mM of NaF and categorized them into 4 groups by K-means clustering. Ingenuity^® pathway analysis revealed several gene networks from gene clusters. The gene networks Up-I and Up-II included many up-regulated genes that were mainly associated with the biological function of induction or prevention of cell death, respectively, such as Atf3, Ddit3 and Fos (for Up-I) and Atf4 and Hspa5 (for Up-II). Interestingly, knockdown of Ddit3 and Hspa5 significantly increased and decreased the number of viable cells, respectively. Moreover, several endoplasmic reticulum (ER) stress-related genes including, Ddit3, Atf4 and Hapa5, were observed in these gene networks. These findings will provide further insight into the molecular mechanisms of NaF-induced cell death accompanying ER stress in oral epithelial cells.

Maize purple plant pigment protects against fluoride-induced oxidative damage of liver and kidney in rats

Anthocyanins are polyphenols and well known for their biological antioxidative benefits. Maize purple plant pigment (MPPP) extracted and separated from maize purple plant is rich in anthocyanins. In the present study, MPPP was used to alleviate the adverse effects generated by fluoride on liver and kidney in rats. The results showed that the ultrastructure of the liver and kidney in fluoride treated rats displayed shrinkage of nuclear and cell volume, swollen mitochondria and endoplasmic reticulum and vacuols formation in the liver and kidney cells. MPPP significantly attenuated these fluoride-induced pathological changes. The MDA levels in serum and liver tissue of fluoride alone treated group were significantly higher than those of the control group (p < 0.05). The presence of 5 g/kg MPPP in the diet reduced the elevation of MDA levels in blood and liver, and increased the SOD and GSH-Px activities in kidney and GSH level in liver and kidney compared with the fluoride alone treated group (p < 0.05). In addition, MPPP alleviated the decrease of Bcl-2 protein expression and the increase of Bax protein expression induced by fluoride. This study demonstrated the protective role of MPPP against fluoride-induced oxidative stress in liver and kidney of rats.

Characterization of a distinct population of circulating human non-adherent endothelial forming cells and their recruitment via intercellular adhesion molecule-3

Circulating vascular progenitor cells contribute to the pathological vasculogenesis of cancer whilst on the other hand offer much promise in therapeutic revascularization in post-occlusion intervention in cardiovascular disease. However, their characterization has been hampered by the many variables to produce them as well as their described phenotypic and functional heterogeneity. Herein we have isolated, enriched for and then characterized a human umbilical cord blood derived CD133⁺ population of non-adherent endothelial forming cells (naEFCs) which expressed the hematopoietic progenitor cell markers (CD133, CD34, CD117, CD90 and CD38) together with mature endothelial cell markers (VEGFR2, CD144 and CD31). These cells also expressed low levels of CD45 but did not express the lymphoid markers (CD3, CD4, CD8) or myeloid markers (CD11b and CD14) which distinguishes them from ‘early’ endothelial progenitor cells (EPCs). Functional studies demonstrated that these naEFCs (i) bound Ulex europaeus lectin, (ii) demonstrated acetylated-low density lipoprotein uptake, (iii) increased vascular cell adhesion molecule (VCAM-1) surface expression in response to tumor necrosis factor and (iv) in co-culture with mature endothelial cells increased the number of tubes, tubule branching and loops in a 3-dimensional in vitro matrix. More importantly, naEFCs placed in vivo generated new lumen containing vasculature lined by CD144 expressing human endothelial cells (ECs). Extensive genomic and proteomic analyses of the naEFCs showed that intercellular adhesion molecule (ICAM)-3 is expressed on their cell surface but not on mature endothelial cells. Furthermore, functional analysis demonstrated that ICAM-3 mediated the rolling and adhesive events of the naEFCs under shear stress. We suggest that the distinct population of naEFCs identified and characterized here represents a new valuable therapeutic target to control aberrant vasculogenesis.