Birth weight and characteristics of endothelial and smooth muscle cell cultures from human umbilical cord vessels.

BACKGROUND: Low birth weight has been related to an increased risk for developing high blood pressure in adult life. The molecular and cellular analysis of umbilical cord artery and vein may provide information about the early vascular characteristics of an individual. We have assessed several phenotype characteristics of the four vascular cell types derived from human umbilical cords of newborns with different birth weight. Further follow-up studies could show the association of those vascular properties with infancy and adulthood blood pressure. METHODS: Endothelial and smooth muscle cell cultures were obtained from umbilical cords from two groups of newborns of birth weight less than 2.8 kg or higher than 3.5 kg. The expression of specific endothelial cell markers (von Willebrand factor, CD31, and the binding and internalization of acetylated low-density lipoprotein) and the smooth muscle cell specific alpha-actin have been evaluated. Cell culture viability, proliferation kinetic, growth fraction (expression of Ki67) and percentage of senescent cells (detection of beta-galactosidase activity at pH 6.0) have been determined. Endothelial cell projection area was determined by morphometric analysis of cell cultures after CD31 immunodetection. RESULTS: The highest variation was found in cell density at the confluence of endothelial cell cultures derived from umbilical cord arteries (66,789 +/- 5,093 cells/cm(2) vs. 45,630 +/- 11,927 cells/cm(2), p < 0.05). Morphometric analysis indicated that the projection area of the artery endothelial cells (1,161 +/- 198 and 1,544 +/- 472 microm(2), p < 0.05), but not those derived from the vein from individuals with a birth weight lower than 2.8 kg was lower than that of cells from individuals with a birth weight higher than 3.5 kg. CONCLUSION: The analysis of umbilical cord artery endothelial cells, which demonstrated differences in cell size related to birth weight, can provide hints about the cellular and molecular links between lower birth weight and increased adult high blood pressure risk.

Procedure to consistently obtain endothelial and smooth muscle cell cultures from umbilical cord vessels.

The prenatal history of an individual can be responsible to some extent for the occurrence of several diseases later in life. Thus, low birth weight has been related to an increased risk of developing hypertension or type 2 diabetes. The molecular and cellular basis of this increased risk could be found in body fluids and cell types that can be obtained just after birth. To get this unique information, a methodology was developed to consistently obtain cultures of 4 cell types, endothelial and smooth muscle cells from both the vein and the arteries present in the umbilical cord of an individual. From 21 umbilical cords processed, 82 of the 84 possible cell cultures were obtained. The cell cultures exhibit the expected cell morphology and cellular characteristics. Thus, endothelial cells express the von Willebrand factor, CD31, as well as bind and internalize acetylated low-density lipoprotein. Vascular smooth muscle cells express the distinctive alpha-actin. Cell cultures can be cryopreserved and grow healthy for several passages. No influence of birth weight of the newborn has been found in the time required to obtain a primary cell culture for any of the 4 cell types. In conclusion, the procedure developed allows one to routinely obtain actively growing vascular cell cultures that could be used to study the molecular and cellular basis of vascular diseases that emerge in adulthood.

First-year blood pressure increase steepest in low birthweight newborns.

AIM: The present research has been undertaken prospectively to study the impact of birthweight and growth pattern on blood pressure changes from birth through the first year of life. METHODS: Parents of newborns born at term (gestational age > 37 weeks) after uncomplicated pregnancies and in the absence of perinatal illness were randomly invited to allow their children to participate in the study. One hundred and forty-nine (84 male and 65 female) newborns were included in the present analysis. The newborns were divided into four groups according to birthweight: < 2500 g (n = 23); 2500-2999 g (n = 39); 3000-3500 g (n = 48); and > 3500 g (n = 39). RESULTS: At birth systolic and diastolic blood pressure were significantly lower and heart rate was significantly higher in those children with the lowest birthweight as compared to those in the other groups. During the first month of life a significant trend, inversely related to birthweight, was present for systolic as well as diastolic blood pressure. After the first month of life, at 3, 6, 9 and at 12 months, systolic and diastolic blood pressure were similar across birthweight groups. In a multiple regression analysis, birthweight was a positive independent determinant of systolic blood pressure at birth and an inverse independent determinant of the increment of systolic blood pressure during the first month of life and of the systolic blood pressure at the end of the first year. CONCLUSIONS: In summary, the present study goes further towards understanding blood pressure changes in low birthweight babies. Beginning at birth, both blood pressure values, as well as changes in blood pressure, provide information about the impact of intrauterine life on the risk of developing hypertension later in life.