Browsing by Author "Sobrevía, Luis"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells(Society for Experimental Biology and Medicine by Sage, 2015) Contador, David; Ezquer, Fernando; Espinosa, Maximiliano; Arango-Rodríguez, Martha; Puebla, Carlos; Sobrevía, Luis; Conget, PauletteThe final product of adipogenesis is a functional adipocyte. This mature cell acquires the necessary machinery for lipid metabolism, loses its proliferation potential, increases its insulin sensitivity, and secretes adipokines. Multipotent mesechymal stromal cells have been recognized as a source of adipocytes both in vivo and in vitro. The in vitro adipogenic differentiation of human MSC (hMSC) has been induced up to now by using a complex stimulus which includes dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin (a classical cocktail) and evaluated according to morphological changes. The present work was aimed at demonstrating that the simultaneous activation of dexamethasone's canonical signaling pathways, through the glucocorticoid receptor and CCAAT-enhancer-binding proteins (C/EBPs) and rosiglitazone through peroxisome proliferator-activated receptor gamma (PPAR-gamma) is sufficient yet necessary for inducing hMSC adipogenic differentiation. It was also ascertained that hMSC exposed just to dexamethasone and rosiglitazone (D&R) differentiated into cells which accumulated neutral lipid droplets, expressed C/EBP-alpha, PPAR-gamma, aP2, lipoprotein lipase, acyl-CoA synthetase, phosphoenolpyruvate carboxykinase, adiponectin, and leptin genes but did not proliferate. Glucose uptake was dose dependent on insulin stimulus and high levels of adipokines were secreted (i.e. displaying not only the morphology but also expressing mature adipocytes' specific genes and functional characteristics). This work has demonstrated that (i) the activating C/EBPs and PPAR-gamma signaling pathways were sufficient to induce adipogenic differentiation from hMSC, (ii) D&R producing functional adipocytes from hMSC, (iii) D&R induce adipogenic differentiation from mammalian MSC (including those which are refractory to classical adipogenic differentiation stimuli). D&R would thus seem to be a useful tool for MSC characterization, studying adipogenesis pathways and producing functional adipocytes.Item Maternal supraphysiological hypercolesterolemia leads to endothelial dysfunction of the human fetoplacental macro and microvasculature(2015) Leiva, Andrea; Salsoso, Rocío; Sáez, Tamara; Silva, Luis; Sanhueza, Carlos; Pardo, Fabian; Sobrevía, LuisMaternal physiological hypercholesterolemia (MPH) occurs in pregnancy assuring fetal growth and development. However, maternal supraphysiological hypercholesterolemia (MSPH) leads to increased atherosclerosis in the fetal vasculature. In this study the maternal and neonatal total cholesterol (TCh) and lipoprotein levels were determined in a group of pregnant women and her newborns. A cut-off value for MSPH was established as maternal TCh levels at term of pregnancy >280 mg/dl. Pregnancies with values over this cut-off point were associated with fetoplacental endothelial dysfunction evaluated as reduced endothelial-dependent vascular dilation in the macro- (umbilical vein; 41 ± 7% and 10± 2% for MPH and MSPH, respectively) and microvasculature (veins in placental stem villi; 52 ± 6% and 1± 0.2% for MPH and MSPH, respectively). The mechanisms involved in this phenomenon include reduced nitric oxide synthase (NOS) activity and therefore reduced nitric oxide (NO) availability in human umbilical vein endothelial cells (HUVEC; reduction of 51 ± 2% compared with MPH) and human placental microvascular endothelial cells (HPMEC; reduction of 83 ± 4% compared with MPH). MSPH was also associated with reduced synthesis of the eNOS cofactor tetrahydrobiopterin (BH4; reduction of 87.5 ± 5% compared with MPH) as well as increased activity of arginases, a group of enzymes that compete with NOS for the substrate L-arginine (1.5 times compared with MPH). Interestingly, the restoration of the BH4 levels and the inhibition of arginases improved the endothelial function impaired by the MSPH condition. Therefore MSPH is a maternal condition likely involved in the endothelial dysfunction and the later development of atherosclerosis described for MSPH offspring. However, the mechanism(s) leading to the development MSPH as well as whether this maternal condition modifies the placental transport of cholesterol and therefore the fetal lipid function are actually unknown.Item Maternal supraphysiological hypercolesterolemia leads to endothelial dysfunction of the human fetoplacental macro and microvasculature(2015) Leiva, Andrea; Salsoso, Rocío; Sáez, Tamara; Silva, Luis; Sanhueza, Carlos; Pardo, Fabian; Sobrevía, LuisMaternal physiological hypercholesterolemia (MPH) occurs in pregnancy assuring fetal growth and development. However, maternal supraphysiological hypercholesterolemia (MSPH) leads to increased atherosclerosis in the fetal vasculature. In this study the maternal and neonatal total cholesterol (TCh) and lipoprotein levels were determined in a group of pregnant women and her newborns. A cut-off value for MSPH was established as maternal TCh levels at term of pregnancy >280 mg/dl. Pregnancies with values over this cut-off point were associated with fetoplacental endothelial dysfunction evaluated as reduced endothelial-dependent vascular dilation in the macro- (umbilical vein; 41 ± 7% and 10± 2% for MPH and MSPH, respectively) and microvasculature (veins in placental stem villi; 52 ± 6% and 1± 0.2% for MPH and MSPH, respectively). The mechanisms involved in this phenomenon include reduced nitric oxide synthase (NOS) activity and therefore reduced nitric oxide (NO) availability in human umbilical vein endothelial cells (HUVEC; reduction of 51 ± 2% compared with MPH) and human placental microvascular endothelial cells (HPMEC; reduction of 83 ± 4% compared with MPH). MSPH was also associated with reduced synthesis of the eNOS cofactor tetrahydrobiopterin (BH4; reduction of 87.5 ± 5% compared with MPH) as well as increased activity of arginases, a group of enzymes that compete with NOS for the substrate L-arginine (1.5 times compared with MPH). Interestingly, the restoration of the BH4 levels and the inhibition of arginases improved the endothelial function impaired by the MSPH condition. Therefore MSPH is a maternal condition likely involved in the endothelial dysfunction and the later development of atherosclerosis described for MSPH offspring. However, the mechanism(s) leading to the development MSPH as well as whether this maternal condition modifies the placental transport of cholesterol and therefore the fetal lipid function are actually unknown.