VEGF en capa muscular de vasos placentarios: expresión en preeclampsia y asociación con status antioxidante / VEGF in muscular layer of placental vessels: expression in preeclampsia and its association with the antioxidant status

Introducción: La preeclampsia es una enfermedad gestacional de origen placentario, de alta prevalencia y morbi-mortalidad materna y fetal. Su patogenia es desconocida, aunque sabemos que en ella ocurre placentación anómala e isquemia placentaria, que conlleva desarrollo de estrés oxidativo (EO) y disfunción endotelial. En condiciones normales la perfusión placentaria es regulada fundamentalmente por óxido nítrico (NO). El factor de crecimiento vascular endotelial (VEGF) es clave en su modulación, aumentando la actividad de enzimas productoras de NO, manteniendo una perfusión placentaria y gestación normales. Objetivo: Caracterizar el perfil de parámetros oxidativos en preeclampsia, asociado con expresión de VEGF en capa muscular de vasos placentarios (CMVP). Metodología: Estudio analítico, observacional, transversal. Se tomaron muestras placentarias y plasmáticas de embarazadas con preeclampsia (n=12) y embarazos normales (n=15). En placenta se determinó: expresión de VEGF en CMVP, malondialdehído y actividad enzimática antioxidante–superóxido dismutasa, glutatión peroxidasa y catalasa. En plasma materno se determinó: F2-isoprostanos y capacidad plasmática antioxidante total (FRAP). Resultados: Pacientes con preeclampsia mostraron mayor expresión de VEGF en CMVP y reducción del FRAP, incremento de F2-isoprostanos y malondialdehído, y menor actividad de superóxido dismutasa (p<0.05). Discusión: Expresión de VEGF en CMVPy parámetros de EO aumentan en preeclampsia. En condiciones normoxémicas, VEGF en CMVP estimula la producción de NO, manteniendo una perfusión placentaria y gestación normales. En condiciones de hipoxia, EO y bajas defensas antioxidantes, como la preeclampsia, VEGF en CMVP favorecería la producción de pro-oxidantes en desmedro de la de NO, lo que contribuiría a explicar la fisiopatología de esta enfermedad.

Introduction: Preeclampsia is a systemic pregnancy disorder, which has high prevalence and high maternal and fetal mortality associated. Its pathogenesis is unknown, but is thought to occur in three phases: abnormal placentation, placental ischemia, which involves development of oxidative stress (OS), and endothelial dysfunction. During normal placental perfusion is regulated primarily by nitric oxide (NO). The vascular endothelial growth factor (VEGF) is a key modulator, increasing the activity of enzymes producing NO, maintaining placental perfusion and normal pregnancy. Objective: To characterize the profile of oxidative parameters in Preeclampsia, associated with VEGF expression in muscular layer of placental vessels (MLPV).Methodology: Analytical, observational, transversal study. Placental and blood plasma samples were taken of pregnant women with preeclampsia (n=12) and normal pregnancies (n=15). In placenta was determined: expression of VEGF in MLPV, malondialdehyde and antioxidant enzyme activity - superoxide dismutase, glutathione peroxidase and catalase. Was determined in maternal plasma F2-isoprostanes and plasma total antioxidant capacity (FRAP). Results: Patients with preeclampsia showed higher expression of VEGF in MLPV and reduced FRAP, increased F2-isoprostanes and malondialdehyde, and decreased activity of superoxide dismutase (p <0.05). Discussion: VEGF expression in MLPV and parameters of OS are both increased in preeclampsia. In normal, VEGF in MLPV stimulates NO production, maintaining a normal pregnancy and placental perfusion. Under hypoxic conditions, OS and low antioxidant defenses, as in preeclampsia, VEGF in MLPV favors the production of pro oxidant agents, at the expense of NO, which would help explain the pathophysiology of this disease.

Modificación del perfil lipídico de la placenta humana por efecto de la desnutrición materna moderada / Modification of lipidic profile of human placenta by effects of moderate maternal undernutrition

The lipid composition of human placenta phospholipids, coming from 9 undernourished women that gave birth to low weight newborns and 9 well norished women, was analyzed using gas-liquid chromatography. Phospholipids of placentas coming from undernourished women, when compared to well nourished women, had significantly lower amounts of w-6 and w-3 fatty acids (40.1 ñ 1.5 vs 42.4 ñ 1.4 and 6.0 ñ 0.7 vs 7.1 ñ 1,3 per cent respectively). The calculated mean melting point was higher in placentas coming from undernourished women. In these women, the low content of polyunsaturated fatty acids and its replacement by short chain fatty acids was not able to balance the high mean melting points. The relative deficiency of essencial fatty acids, the low saturation index and the high mean melting point of undernourished women's placental phospholipids, may suggest a lower membrane fluidity and a subnormal essencial fatty acid content of fetal organs, that are essencial for normal growth and development