Alterações histopatológicas na veia umbilical de gestantes com excesso de peso

Abstract

Excess weight during pregnancy is a condition that can affect both mother and fetus, through the maternal-fetal interface, which is constituted by the placenta and umbilical cord. The umbilical vein is responsible for transporting oxygen and nutrients to the fetus, and its proper functioning depends on the integrity of its structure. The remodeling of the umbilical vein represents one of the causes of inadequate transport of nutrients to the fetus, being potentially deleterious. The objective of this study is to evaluate whether maternal overweight alters the structural characteristics of the umbilical vein. Umbilical cords were collected from eutrophic pregnant women (control; n=19) and from overweight and obese pregnant women (SP/OB; n=16). The umbilical veins were processed according to histological routine and analyzed for the following parameters: morphometry analysis, collagen deposition, glycosaminoglycan level and cell proliferation. The correlation analysis of all parameters with the body mass index (BMI) of the pregnant women was also performed. The BMI of the SP/OB group was higher than the control group (28.0±0.7 vs. 22.3±0.4, respectively; p<0.0001). Veins from SP/OB pregnant women were found to have greater total area (4.16±0.45 vs. 3.1±0.22 mm²), wall area (3.29±0.36 vs. 2.43±0.17; mm²), wall thickness (0.58±0.04 vs. 0.48±0.02 mm) and diameter (2.31±0.13 vs. 1.98±0.07 mm). There was higher collagen labeling in the perivascular region of the SP/OB group (71.08±0.5 vs. 57.74±0.02 %) and higher amount of type III collagen in the vascular smooth muscle (5.14±0.54 vs. 3.48±0.5 %). The proliferation of muscle (0.38±0.06 vs. 0.14±0.04 %) and perivascular (1.72±0.54 vs. 0.07±0.02 %) cells was higher in SP/OB pregnant women. A positive, although weak, correlation was observed between BMI with vessel thickness (r=0.357; p=0.03) and with type III collagen deposition in vascular smooth muscle (r=0.567; p=0.02). It is concluded that overweight is capable of structurally altering the umbilical vein, causing vascular remodeling of the vessel, through hypertrophy and hyperplasia.