1,720,989 research outputs found
In vitro sex-dependent properties of male and female human umbilical vein endothelial cells (HUVECs)
No full textLoss of normal endothelial function is a critical step in the development and clinical expression of atherosclerosis and cardiovascular diseases (CVDs). Substantial sex/gender differences have been described with a prevalence in men than women until midlife. However, the occurrence of CVD increases with age in both sexes. Despite these well-established observations, very little is known about innate gender differences existing between male and female endothelial cells (ECs).
To characterize sex-dependent differences, we compared in vitro properties of male and female cells obtained from human umbilical vein ECs (HUVECs). Importantly, we always used HUVECs pooled from two or more donors to minimize the variability associated with cells derived from a single male or female newborn donor.
First, we focused our attention on properties shown by male and female HUVECs grown in standard conditions i.e. in 199 medium supplemented with FBS. We demonstrated that metabolic activity was similar in cells of both sex. On the other hand, female HUVECs expressed an higher amount of endothelial Nitric Oxide Synthase (eNOS) mRNA and protein, and showed greater migratory capabilities in comparison to male cells.
The female advantage in younger women has been attributed to vascular protection by estrogens, which is lost with menopause. To study the contribution of estrogens in EC physiology, male and female HUVECs were cultured in the absence of estrogens i.e. in phenol red-free 199 medium supplemented with charcoal-stripped FBS. We found that loss of estrogens induced a significant decrease in metabolic activity in comparison to growth standard conditions in cells of both sex. Very interestingly, the expression of eNOS was decreased in the absence in estrogens only in female HUVECs.
These preliminary results confirm a role for estrogen in the modulation of in vitro EC physiology. Further studies should be carried out to determine whether innate gender differences between male and female cells and estrogens might play a crucial role in the vascular protection responsible for the lower prevalence of CVDs in women until menopause
Charcoal-stripped serum impairs growth and sprouting of male and female human umbilical vein endothelial cells (HUVECs) regardless of estrogens
No full textLoss of a normal endothelial function crucially contributes to the development and clinical expression of atherosclerosis and cardiovascular disease (CVD). Despite substantial sex/gender differences have been described in the occurrence of CVD, very little is known about innate sex properties of male and female endothelial cells (ECs).
To characterize putative sex-dependent differences, we compared in vitro properties of male and female human umbilical vein ECs (HUVECs) showing that female HUVECs express an higher amount of eNOS mRNA and protein, and possess greater migratory capabilities in comparison to male cells. Male and female HUVECs did not show however any significant difference in metabolic activity.
Since a crucial issue in the sex-related incidence of CVD concerns estrogens, we compared male and female HUVECs grown in standard medium or in a nominally estrogen-free medium containing charcoal-stripped FBS. We found that lack of hormones induced in both sexes: i) a decrease in cell number, and as a consequence in metabolic activity (evaluated by MTT and ATP); ii) an impaired in vitro angiogenesis. All the effects were not reverted by 17-beta-estradiol (E2). These results suggest that estrogens did not represent a critical factor for the maintenance of EC behavior regardless of cell sex. Experiments are ongoing to identify substance(s) responsible for EC rescue from charcoal-stripped FBS-induced impairment in growth and angiogenesis
Sex-dependent properties of male and female human umbilical vein endothelial cells (HUVECs): focus on eNOS
No full textAtherosclerosis and cardiovascular diseases (CVDs) are classical examples of diseases where sex/gender differences have been described. A significant body of evidence suggests that CVDs are less prevalent in women than men until midlife, and the female advantage has been attributed to estrogens, which are lost with menopause. Since the earliest event in the onset of atherosclerosis and CVDs is endothelial dysfunction (ED) - a reduced release of nitric oxide (NO) coupled with an increase in Reactive Oxygen Species (ROS) in the vascular wall - many in vitro studies have been focused on endothelial cells (ECs). However, the sex of ECs has not been consistently reported in these studies, even when the effects of sex hormones were analyzed.
To better study the influence of estrogens on metabolic properties of human male and female umbilical vein ECs (HUVECs), we cultured HUVECs in a nominally hormone-free medium - consisting of a phenol-red free medium supplemented with charcoal-stripped serum (CS-FBS) - typically used to assess in vitro hormone biological activities. We found that HUVECs of both sexes stopped to grow and to sprout in the absence of hormones, and neither 17-β2 estradiol nor dihydrotestosterone reverted these inhibitory effects. We concluded that HUVEC growth and sprouting critically require some serum components - other than sex hormones - that are lost in the CS-FBS. We focused our attention on fatty acids (FAs) because: 1) metabolic pathways are emerging as important regulators of angiogenesis; 2) FAs have been crucially involved in the regulation of EC proliferation; 3) CS-FBS is fully depleted from FAs. As a matter of fact, the inhibitory effects on MTT absorbance, cell number and 3-D sprouting observed in HUVECs cultured in CS-FBS containing media were reverted by adding back sodium acetate and palmitic acid. These data confirm a fundamental role for FAs in the regulation of EC growth and sprouting. However, no substantial differences were found between male and female EC behavior in these conditions.
To further investigate inborn sex differences in ECs, we focused on a relevant issue that is the role of eNOS and of its product NO. Endothelium-produced NO has important functions on ECs themselves, playing a key role not only in CVD onset and development, but also in angiogenesis, by stimulating EC proliferation, migration and differentiation. We found that female HUVECs constitutively expressed an higher amount of eNOS both at mRNA and protein level. Moreover, female HUVECs possess greater migratory and 3-D spheroid sprouting capabilities in comparison to male cells. The increased migratory and angiogenic capabilities observed in female HUVECs were counteracted by the pretreatment with the NO synthesis inhibitor L-NAME.
These preliminary results suggest that the constitutive higher expression of eNOS observed in female HUVECs might contribute to the protection against CVDs characteristic of the younger female population. We will carry out further studies on ECs from different sources and ages to determine if the increase in eNOS expression observed in female HUVECs is preserved during lifetime and in ECs obtained from different vascular bed
Silencing of Eps8 inhibits in vitro angiogenesis
No full textAims: Eps8 is an actin-binding protein which has been proposed as a regulator of cancer cell motility and invasion. However, nothing much is known about its contribution to the invasive properties of endothelial cells (ECs), and more generally to angiogenesis. Main methods: Expression and silencing of Eps8 were evaluated by western blot analysis. The effect of Eps8 silencing on cell number and VEGF-induced signaling was tested with standard methods. Migration was evaluated by scratch wound assay and morphogenesis with 2-dimensional (2-D) tube formation and 3-dimensional (3-D) sprouting assays. Actin cytoskeleton was visualized by immunofluorescence. Key findings: We found that silencing of Eps8 profoundly affected the ability of human ECs to migrate and to undergo tube formation and sprouting in 2-D and 3-D in vitro assays, respectively. Notably, capillary-like outgrowth was strictly depending on Eps8 expression also in human tumor-derived ECs. Significance: Our data demonstrate for the first time the involvement of Eps8 in the morphological processes required for in vitro angiogenesis, and suggest that this protein might represent a common target for the design of new anticancer drugs, acting at the same time on both tumor and endothelial cells
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
