Influência da concentração de leptina no sangue materno, no sangue do cordão umbilical e na placenta no peso e condições do feto ao nascimento

• Ano de defesa: 2013
• Autor(a) principal: Maria Carmen Neves Souza Carmo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Parturientes; Recém-nascidos; Leptina; Gravidez; Bioquímica e imunologia
• Link de acesso: http://hdl.handle.net/1843/BUBD-9ZHJMC

Pregnancy is characterized by endocrine and metabolic adaptations of the mother, including increasing in weight and adipose tissue. Leptin is secreted by adipose tissue, and it is also expressed in other organs such as gastrointestinal tract, bone, lung, intestine, kidney, liver, skin, stomach, heart, spleen and placenta, suggesting pleiotropic actions. Although the mechanisms that regulate the weights of mother and fetus during pregnancy are unclear, it is possible that leptin has a role as a regulator factor. Thus, our goal in this study was to analyze leptin levels in maternal blood and umbilical cord and their relationship with fetal weight and conditions at birth. For this, twenty-five patients were recruited at public hospitals and maternal peripheral blood samples and, after parturition, placental tissue fragment and blood of the umbilical arteries and vein were collected. Leptin concentration in maternal and fetal blood, leptin expression in placenta and leptin receptor expression in placenta (Ob-Rb) were obtained. After the combined analysis of all pregnant women, they were divided into two groups (low leptin and high leptin levels), according to leptin concentration in maternal peripheral blood, to enable comparisons in statistical analyzes. Correlations were also performed. The average age of mothers was 28 years, with body mass index of 22.5 kg/m2 and average weight gain of 12.8 kg. The newborns had a mean weight of 3.15 kg and average length of 45.9 cm. After the division of the groups, it was observed that the mothers in high leptin level group had age, BMI and weight before pregnancy and weight in late pregnancy significantly higher than the mothers of low leptin level group. Although no statistical differences were observed between groups regarding serum concentrations of leptin in the umbilical arteries and vein, it was observed a significant increase in fetal leptin retained in the high leptin level group. Both groups presented positive correlation between umbilical vein and arteries leptin levels and also between placenta leptin levels and maternal BMI and weight before pregnancy. In the low leptin level group it was observed only positive correlation between umbilical vein and arteries leptin levels and also between placenta leptin levels and maternal BMI and weight before pregnancy. In the high leptin level group it was observed the same correlations observed in the former group and also positive correlation between maternal leptin levels and maternal weight before pregnancy, negative correlation between maternal leptin levels and Ob-Rb expression in placenta, positive correlation between blood cord leptin levels and fetal weight and negative correlation between newborn Apgar score and umbilical vein leptin levels. In conclusion, cord leptin levels, but not maternal blood leptin levels, may play a role in determining fetal weight. Nevertheless, higher umbilical vein leptin levels were associated with low Apgar scores. Keywords: pregnancy, leptin, pregnant women, newborns.