Browsing by Author "Westermeier Lafuente, Francisco David"
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- ItemEndothelial dysfunction and reduced insulin response in umbilical vein from the offspring of maternal obesity pregnancies(2016) Villalobos Labra, Roberto Esteban; Pizarro, Carolina; Westermeier Lafuente, Francisco David; Sáez Pedraza, Pablo José; Sobrevía Luarte, Luis Alberto; Farías Jofré, Marcelo EnriqueINTRODUCTION: Maternal obesity (MO) has been recognized as a risk factor for maternal and fetal complications, including offspring´s insulin resistance (IR) later in life. We evaluated the effect of MO in endothelial cells function and umbilical vein vasodilatation in response to insulin. METHODS: Primary cultures of human umbilical vein endothelial cells (HUVEC) and rings were isolated from normal (HUVEC-N) or MO (HUVEC-OB) pregnancies attending to Pontificia Universidad Católica de Chile Hospital. Total and/or phosphorylated level of IRS-1, Akt, MAPK and eNOS, were measured by western blot in protein extracts of cells exposed to insulin (1 nM, 30 min). Wire myography was used to evaluate functional effect of insulin in umbilical vein rings. Cellular nitric oxide (NO) availability was measured using the fluorescent probe diaminofluorescein (DAF). Values are Mean±S.E.M. RESULTS: MO was associated with inhibition of IRS-1 and reduced phosphorylation of Akt (2,24±0,06 vs 6,85±0,12; p<0,01) and MAPK (4,13±0,65 vs 13,12±1,67; p<0,01) in response to insulin, in HUVEC. We found that total eNOS and the activating phosphorylation on Ser1177 was reduced (0,98±0,03 vs 5,45±0,85; p<0,01) in HUVEC-OB compared to HUVEC-N. Conversely, the inhibitory phosphorylation on Thr495 was increased (1,88±0,08 vs 1,51±0,14; p<0,01) in HUVEC-OB. Also, HUVEC-N exposed to insulin (1nM) showed increased levels of NO at 5, 15 and 30 min of incubation, an effect blocked by the inhibitor of NOS L-NAME. In contrast, insulin did not increase NO production in HUVECOB. Finally, vein rings from MO showed abolished relaxation in response to insulin, meanwhile rings from normal pregnancies showed a 20% of insulin dilator effect, which was blocked by L-NAME. CONCLUSIONS: We have shown evidence that MO promotes less vasodilation of umbilical vein in response to insulin, due to an inhibitory state of insulin signaling and eNOS activation, with the consequent absence of insulin-dependent NO production by HUVEC affected by MO.
- ItemEquilibrative nucleoside transporters in fetal endothelial dysfunction in diabetes mellitus and hyperglycaemia(2009) Westermeier Lafuente, Francisco David; Puebla Aracena, Carlos Alberto; Vega Pizarro, José Luis Eduardo; Farías Jofré, Marcelo Enrique; Escudero Orozco, Carlos Alonso; Casanello Toledo, Paola Cecilia; Sobrevía Luarte, Luis AlbertoDiabetes mellitus types 1 and 2, and gestational diabetes are characterized by abnormal D-glucose metabolism and hyperglycaemia, and induce foetal endothelial dysfunction with implications in adult life increasing the risk of vascular diseases. Synthesis of nitric oxide (NO) and uptake of L-arginine (i.e. the L-arginine/NO signalling pathway) and adenosine (a vasoactive endogenous nucleoside) by the umbilical vein endothelium is altered in pathological pregnancies, including pregnancies with pre-established diabetes mellitus or in gestational diabetes. The mechanisms underlying these alterations include differential expression of equilibrative nucleoside transporters (ENTs), amino acid transporters and NO synthases (NOS). Modulation of ENTs and NOS expression and activity in endothelium involves several signalling molecules, including protein kinase C, mitogen-activated protein kinases p42 and p44, calcium and phosphatidyl inositol 3 kinase. Elevated extracellular D-glucose and diabetes alters human endothelial function. However, information regarding modulation the transport capacity as well as expression of ENTs is limited. This review focuses on the effect of diabetes mellitus and gestational diabetes, and hyperglycaemia on the reported mechanisms described for transcriptional and posttranscriptional regulation of ENTs, and the potential consequences for foetal endothelial function in these pathologies. Recent available information regarding functional consequences of an abnormal environment on the functionality of the endothelium from microvasculature of the human placenta is mentioned. The available information is scarce, but it could contribute to a better understanding of the cell and molecular basis of the altered vascular endothelial function in this pathological conditions, emphasizing the key role of this type of epithelium in fetal-placental function and the normal foetal development and growth.
- ItemMaternal obesity and neonatal insulin resistance in the origin of metabolic syndrome in childhood(2013) Farías Jofré, Marcelo Enrique; Villalobos Labra, Roberto Esteban; Sáez Pedraza, Pablo José; Westermeier Lafuente, Francisco David; Poblete Lizana, José Andrés; Kusanovic, Juan Pedro; Mardones S., Francisco; Sobrevía Luarte, Luis AlbertoObesity during pregnancy has been recognized as an independent risk factor for maternal and fetal complications, including congenital anomalies, gestational diabetes mellitus, gestational hypertension and preeclampsia, caesarean delivery, macrosomia (birth weight > 4000 g), increased neonatal adiposity and hyperinsulinemia. In addition to perinatal complications associated to maternal obesity, rising epidemiological evidence has suggested the intrauterine programming of whole body insulin resistance (IR) in the offspring of obese pregnant woman, evaluated both at early neonatal stage and at young adulthood. Our cohort data showed association among elevated neonatal anthropometry measurements (birth weight and height) and increased levels of waist circumpherence and blood pressure in childohood, two components of the metabolic syndrome (MetS). In the other hand, the homeostasis model assesment index of insulin resistance (HOMA-IR) was correlated to the number of MetS components in this population. In order to describe potential mechanisms of relationship between maternal obesity and future development of MetS, we have evaluated modulators of neonatal insulin signaling pathway in human and animal models of maternal obesity. We have found increased levels of neonatal insulin secretion (serum C-peptide) and sub-clinical markers of cellular insulin resistance and endoplasmic reticulum stress (ER-stress) in offsprings of women with maternal weight excess. The ER stress response has been related to IR and diabetes mellitus development in multiple models of obesity. Thus, a mechanistic link could be proposed between maternal obesity, ER stress and IR in fetal tissues as part of the physiopathology route that connects abnormal intrauterine nutrition with elevated risk of MetS in childhood.
- ItemPotential Cell Signalling Mechanisms Involved in Differential Placental Angiogenesis in Mild and Severe Pre-Eclampsia(2009) Escudero, Carlos; Westermeier Lafuente, Francisco David; Sobrevía Luarte, Luis Alberto
- ItemReduced Insulin Response in Human Umbilical Vein Endothelial Cells from Pregnancies with Maternal Obesity Is Associated with Activation of PERK Branch of Endoplasmic Reticulum Stress Pathway(2013) Farías Jofré, Marcelo Enrique; Westermeier Lafuente, Francisco David; Kusanovic Pivcevic, Juan Pedro; Poblete Lizana, José Andrés; Mardones S., Francisco; Sobrevía Luarte, Luis Alberto