Estrogen receptor expression and synthesis in the human internal thoracic artery

Comparative genome-wide transcriptional analysis of human left and right internal mammary arteries

In coronary artery bypass grafting (CABG), the combined use of left and right internal mammary arteries (LIMA and RIMA) - collectively known as bilateral IMAs (BIMAs) provides a survival advantage over the use of LIMA alone. However, gene expression in RIMA has never been compared to that in LIMA. Here we report a genome-wide transcriptional analysis of BIMA to investigate the expression profiles of these conduits in patients undergoing CABG. As expected, in comparing the BIMAs to the aorta, we found differences in pathways and processes associated with atherosclerosis, inflammation, and cell signaling - pathways which provide biological support for the observation that BIMA grafts deliver long-term benefits to the patients and protect against continued atherosclerosis. These data support the widespread use of BIMAs as the preferred conduits in CABG.

Hormone replacement therapy and cardioprotection: a new dawn? A statement of the Study Group on Cardiovascular Disease in Women of the Italian Society of Cardiology on hormone replacement therapy in postmenopausal women

Cardiovascular disease is the leading cause of death in women in Western countries. Despite preventive strategies, in the past decades the incidence of cardiovascular events has shown a decline in men but a rise in women, matching the growth of the population of postmenopausal women. Several epidemiological findings suggest the causative pathophysiological role of ovarian hormone deficiency in the development of cardiovascular disease in women. Observational and randomized studies have suggested that hormone replacement therapy in early postmenopause could be beneficial from a cardiovascular point of view. Conversely, aging, time since menopause and presence of cardiovascular risk factors or cardiovascular disease may decrease its efficacy and increase the risk of cardiovascular events. It is plausible that the unfavorable effects of the estrogen/progestin combination used in the randomized studies are not related to the hormone preparation per se but rather to the use of hormones in the less receptive group of women, older and with cardiovascular risk factors. Clinical judgment, choice of the right dose and estrogen/progestin combination are of pivotal importance to maximize the beneficial effect of estrogen replacement therapy/hormone replacement therapy, especially if given within a reasonable time after the menopause to women who need the therapy for the relief of menopausal symptoms.

Human-derived nanoparticles and vascular response to injury in rabbit carotid arteries: proof of principle

Self-calcifying, self-replicating nanoparticles have been isolated from calcified human tissues. However, it is unclear if these nanoparticles participate in disease processes. Therefore, this study was designed to preliminarily test the hypothesis that human-derived nanoparticles are causal to arterial disease processes. One carotid artery of 3 kg male rabbits was denuded of endothelium; the contralateral artery remained unoperated as a control. Each rabbit was injected intravenously with either saline, calcified, or decalcified nanoparticles cultured from calcified human arteries or kidney stones. After 35 days, both injured and control arteries were removed for histological examination. Injured arteries from rabbits injected with saline showed minimal, eccentric intimal hyperplasia. Injured arteries from rabbits injected with calcified kidney stone- and arterial-derived nanoparticles occluded, sometimes with canalization. The calcified kidney stone-derived nanoparticles caused calcifications within the occlusion. Responses to injury in rabbits injected with decalcified kidney stone-derived nanoparticles were similar to those observed in saline-injected animals. However, decalcified arterial-derived nanoparticles produced intimal hyperplasia that varied from moderate to occlusion with canalization and calcification. This study offers the first evidence that there may be a causal relationship between human-derived nanoparticles and response to injury including calcification in arteries with damaged endothelium.

E4F1, a novel estrogen-responsive gene in possible atheroprotection, revealed by microarray analysis

Estrogen has been postulated to be involved in inhibition of vascular smooth muscle cell (VSMC) proliferation mainly via estrogen receptor (ER), but the detailed mechanism has remained primarily unknown. Therefore, in this study, microarray analysis was used in two types of cultured human VSMCs: one positive for ER alpha, and the other for ER beta, which were treated by estrogens to detect the estrogen-responsive genes. We also used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate mRNA levels of selective target gene (TG) in these cells. We further studied whether the TG product was involved in inhibition of proliferation using small interfering RNA (siRNA) of the TG transfection. We subsequently used quantitative RT-PCR and in situ hybridization analysis to evaluate the expression of these gene products in human aorta. E4F1, a possible inducer of cell growth arrest, was markedly increased only in ER alpha-positive VSMCs by estrogens in both microarray and RT-PCR analyses. Blocking of E4F1 using siRNA suppressed estrogenic inhibition of ER alpha-positive VSMC proliferation. E4F1 mRNA was abundant in premenopausal female aorta with mild atherosclerotic changes. E4F1 is therefore considered one of the estrogen-responsive genes involving ER alpha-mediated inhibition of VSMC proliferation and may play an important role in estrogen-related atheroprotection of human aorta.