Search

Abstract: Migration and proliferation of endothelial cells are involved in re-endothelialization and angiogenesis, two important cardiovascular processes that are increased in response to estrogens. RhoA, a small GTPase which controls multiple cellular processes, is involved in the control of cell migration and proliferation. Our aim was to study the role of RhoA on estradiol-induced migration and proliferation and its dependence on estrogen receptors activity. Human umbilical vein endothelial cells were stimulated with estradiol, in the presence or absence of ICI 182780 (estrogen receptors antagonist) and Y-27632 (Rho kinase inhibitor). Estradiol increased Rho GEF-1 gene expression and RhoA (gene and protein expression and activity) in an estrogen receptor-dependent manner. Cell migration, stress fiber formation and cell proliferation were increased in response to estradiol and were also dependent on the estrogen receptors and RhoA activation. Estradiol decreased p27 levels, and significantly raised the expression of cyclins and CDK. These effects were counteracted by the use of either ICI 182780 or Y-27632. In conclusion, estradiol enhances the RhoA/ROCK pathway and increases cell cycle-related protein expression by acting through estrogen receptors. This results in an enhanced migration and proliferation of endothelial cells. [Copyright &y& Elsevier]

The CD40/CD40L system is considered a crucial modulator of the inflammatory process underlying the progression and complication of atheroma plaques. The soluble fraction of CD40L (sCD40L) is a reliable indicator of the CD40/CD40L system. Our purpose was to investigate whether a therapeutic dose of estradiol, by either the oral or the transdermal route, was associated with changes in circulating levels of sCD40L. Forty-seven women completed a 4-week course of treatment with either oral estradiol valerate (2 mg/day, 20 women) or transdermal estradiol (50 μg/day, 27 women). Serum levels of sCD40L were measured by conventional enzyme-linked immunosorbent assay. Oral, but not transdermal estradiol, modified the lipid profile. Levels of sCD40L, however, remained unchanged compared with baseline. This neutral effect of oral or transdermal estradiol on sCD40L levels further advances our knowledge on the effects of estrogens on mechanisms involved in the progression and complication of atherosclerosis. [ABSTRACT FROM AUTHOR]

Objective: To examine the proliferative effect of of raloxifene on human umbilical-vein endothelial cells (HUVECs), and to investigate whether there is an associated increased expression of some key regulators of the cell cycle. Design: Cell culture for different incubation times. Setting: University research laboratory. Patient(s): Sources of HUVECs. Intervention(s): Measurement of cell proliferation, of protein levels of cyclin A, cyclin B1, cyclin D1, cyclin-dependent protein kinase (CDK) 2, CDK4, and p27Kip1, and of messenger RNA expression of cyclin A, cyclin B1, and p27Kip1. Main Outcome Measure(s): Cell proliferation was measured by the 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the bromo-2′-deoxyuridine assay, and the sodium 3′-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate assay. Changes in protein expression were measured by immunoblotting, and modifications in gene expression were measured by quantitative real-time polymerase chain reaction. Result(s): Both 1 nM and 10 nM of either E2 or raloxifene achieved a similar increase in cell proliferation. The pure antiestrogen ICI 182780 only blocked the E2-induced proliferative effect. Western blot experiments detected an increase in the expression of only cyclin A and B1, and a decreasing trend for p27Kip1. Enhancements in gene expression were observed in response to E2 and raloxifene for cyclin A and B1. No significant changes were found for p27Kip1. The ICI 182780 effectively abrogated the increased gene expression associated with E2 for cyclin B1, but not for cyclin A. In contrast, ICI 182780 was ineffective in the case of raloxifene. Conclusion(s): Raloxifene increased the proliferation of HUVECs in association with enhanced gene expression of cyclins A and B1. [Copyright &y& Elsevier]

Abstract: Objective: Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, is a novel cardiovascular risk factor produced by endothelial cells. ADMA levels are mainly regulated by the activity of dimethylarginine dimethylaminohydrolases (DDAH). Endothelial release of ADMA is increased in the presence of oxidized LDL cholesterol (oxLDL), whereas estrogens stimulate NO production by endothelial cells by increasing both expression and activity of NO synthase and by reducing ADMA levels. Thus, the aim of the present study was to evaluate the estradiol effects on the DDAH/ADMA/NO pathway in cultured human umbilical vein endothelial cells (HUVEC) exposed to LDL. Methods: After 24 h of exposure to various treatments, culture medium was collected to measure NO production by using an amperometric sensor specific for NO, and to measure dimethylarginines by high-performance liquid chromatography (HPLC). DDAH-I and II mRNA expression and protein content were quantified by real-time PCR assay and immunoblotting, respectively. Results: Exposure of HUVEC to 100 μg/mL oxLDL, but not to 100 μg/mL of native LDL (nLDL), reduced DDAH-II expression at both the mRNA as well as the protein levels, which in turn increased ADMA levels and reduced NO production. Estradiol (1 nM) alone increased DDAH-II mRNA and protein expression, which reduced ADMA levels and increased NO production. In cells exposed to estradiol in combination with either nLDL or oxLDL, levels of DDAH-II, ADMA, and NO were the same as those for estradiol alone. Conclusion: Estradiol completely reverses the effects induced by oxLDL on the DDAH/ADMA/NO pathway. [Copyright &y& Elsevier]

We investigated the effect of a therapeutic dose of raloxifene on the plasma levels of myeloperoxidase and F2α-isoprostanes, two markers of oxidative stress recently described as reliable indicators of coronary heart disease. Contrary to changes described in the literature for estrogens (E), raloxifene did not modify the levels of either myeloproxidase or F2α-isoprostanes after 3 or 6 months of treatment. [Copyright &y& Elsevier]

Objective: To examine the effects of raloxifene on prostacyclin production by human umbilical vein endothelial cells (HUVEC) and to shed light on the molecular details of that action. Design: Cell culture for 4, 8, 16, 24, and 48 hours. Setting: University research laboratory. Patient(s): Source of HUVEC. Intervention(s): Measurement of prostacyclin production and of protein levels and mRNA expression of cyclooxygenase (COX)-1 and -2. Main Outcome Measure(s): Prostacyclin production was measured by enzyme immunoassay, the mRNA expression of COX-1 was measured by quantitative real time-polymerase chain reaction, and the protein levels of COX-1 and -2 were measured by immunoblotting. Result(s): Raloxifene significantly increased prostacyclin release in a time- and dose-dependent manner, being higher than control after 24 hours. Raloxifene, at 0.1–10 nM, increased the mRNA expression of COX-1 and the protein content of both COX-1 as well as COX-2. All of these effects were independent of the classical pathway for estrogen receptor (ER) activation because the treatment of cells with the ER antagonist ICI 182780 did not eliminate any of the effects. Although treatment with either the selective COX-1 inhibitor SC-560 or the selective COX-2 inhibitor NS-398 significantly diminished prostacyclin release (20% ± 5% and 24% ± 7%, respectively), co-treatment with raloxifene and either SC-560 or NS-398 was followed by a smaller increase than that achieved by raloxifene alone. The nonselective COX inhibitor indomethacin, however, reduced prostacyclin production to 37% ± 11% of control values. Conclusion(s): Raloxifene increased HUVEC prostacyclin release through a mechanism possibly distinct from the classical ER pathway and involving enhanced COX-1 and COX-2 expression and activity. [Copyright &y& Elsevier]

The presence of antimicrobial and pesticide residues in products sourced from peasant family farms selected from eight regions of Chile was determined. A total of 204 samples were analyzed from family farm products, including honey, lettuce, tomato, strawberry, raspberry, lamb meat, and cow’s milk. Pesticide residues were found in 43 of 107 samples tested for them, but only 4 samples had concentrations that exceeded the maximum residue limits (MRLs) set by Chilean regulations. As for animal products, 2 of 15 cow’s milk samples tested positive for permethrin residues; however, these concentrations did not exceed Chilean MRLs. No pesticide residues were detected in honey samples. As for antimicrobial drugs, 4 of 14 lamb meat samples and 11 of 79 cow’s milk samples tested positive for different classes of antimicrobial residues, such as tetracyclines, macrolides, aminoglycosides, and β-lactams. Among these, only three samples exceeded the MRLs for these matrices. Traces of tetracyclines and sulfonamides were detected in 7 of 29 honey samples. These findings show that these chemical contaminants are present in trace concentrations in foodstuffs produced by peasant family farms in Chile; however, most residues did not exceed the regulatory limits. This study is the first assessment of the presence of residues from antimicrobial drugs and pesticides in food products sourced from peasant family farms in Chile. Data about the current state of drug residues in this segment of food products provide a baseline for efforts to close possible gaps in current surveillance schemes. [ABSTRACT FROM AUTHOR]

Improvements and good practices (GPs) in rural environments are often developed by peasants themselves and shared among trust-based networks. The level of adoption of GPs by peasant family farmers (PFF) has been poorly studied. This paper describes the performance and results of the innovation adoption index (InAI) and rate (InAR) which were used to estimate the adoption of GPs for pesticide and veterinary drug use by PFF from eight different regions of Chile. Surveys were conducted among 257 farmers to find out about the adoption (yes/no) of a set of GPs in the adequate handling, use and storage of these chemical products, as well as some identifying information. The farmers in this study are producers of berries, dairy cows, honey and vegetables. The results of the survey showed an average of 57.33% GPs were adopted by farmers. Group averages of 55.23–61.32% were observed in the numbers of practices adopted by farmers. This survey data collection was part of a wider study intended to design a national plan to reduce chemical residues in food produced by PFF in Chile, with a focus on organizing practical workshops with extension officers and farmers. [ABSTRACT FROM AUTHOR]

The article focuses on a study of Salmonella enterica infection in pinnipeds in Chile. The study involved 13 malnourished and stranded South American sea lions or Otaria flavescens discovered from August to December 2010. Peptone water was used to isolate bacteria in the swab samples. It mentions the detection of S. enterica serotypes Newport and Havana in human population in the country.

Vascular effects of estradiol are being investigated because there are controversies among clinical and experimental studies. DNA microarrays were used to investigate global gene expression patterns in cultured human umbilical vein endothelial cells (HUVEC) exposed to 1 nmol/L estradiol for 24 hours. When compared to control, 187 genes were identified as differentially expressed with 1.9-fold change threshold. Supervised principal component analysis and hierarchical cluster analysis revealed the differences between control and estradiol-treated samples. Physiological concentrations of estradiol are sufficient to elicit significant changes in HUVEC gene expression. Notch signaling, actin cytoskeleton signaling, pentose phosphate pathway, axonal guidance signaling and integrin signaling were the top-five canonical pathways significantly regulated by estrogen. A total of 26 regulatory networks were identified as estrogen responsive. Microarray data were confirmed by quantitative RT-PCR in cardiovascular meaning genes; cyclooxigenase (COX)1, dimethylarginine dimethylaminohydrolase (DDAH)2, phospholipase A2 group IV (PLA2G4) B, and 7-dehydrocholesterol reductase were upregulated by estradiol in a dose-dependent and estrogen receptor-dependent way, whereas COX2, DDAH1 and PLA2G4A remained unaltered. Moreover, estradiol-induced COX1 gene expression resulted in increased COX1 protein content and enhanced prostacyclin production. DDAH2 protein content was also increased, which in turn decreased asymmetric dimethylarginine concentration and increased NO release. All stimulated effects of estradiol on gene and protein expression were estrogen receptor-dependent, since were abolished in the presence of the estrogen receptor antagonist ICI 182780. This study identifies new vascular mechanisms of action by which estradiol may contribute to a wide range of biological processes. [ABSTRACT FROM AUTHOR]