Differences in umbilical cord serum lipid levels with mode of delivery

Sex-specific responses in placental fatty acid oxidation, esterification and transfer capacity to maternal obesity

Fatty acid metabolism and oxidation capacity in the placenta, which likely affects the rate and composition of lipid delivered to the fetus remains poorly understood. Long chain polyunsaturated fatty acids, such as docosahexaenoic acid (DHA), are critical for fetal growth and brain development. We determined the impact of maternal obesity on placental fatty acid oxidation, esterification and transport capacity by measuring PhosphatidylCholine (PC) and LysoPhosphatidylCholine (LPC) containing DHA by mass spectrometry in mother-placenta-baby triads as well as placental free carnitine and acylcarnitine metabolites in women with normal and obese pre-pregnancy BMI. Placental protein expression of enzymes involved in beta-oxidation and esterification pathways, MFSD2a (lysophosphatidylcholine transporter) and OCTN2 (carnitine transporter) expression in syncytiotrophoblast microvillous (MVM) and basal (BM) membranes were determined by Western Blot. Maternal obesity was associated with decreased umbilical cord plasma DHA in LPC and PC fractions in male, but not female, fetuses. Basal membrane MFSD2a protein expression was increased in placenta of males of obese mothers. In female placentas, despite an increased MVM OCTN2 expression, maternal obesity was associated with a reduced MUFA-carnitine levels and increased esterification enzymes. We speculate that lower DHA-PL in fetal circulation of male offspring of obese mothers, despite a significant increase in transporter expression for LPC-DHA, may lead to low DHA needed for brain development contributing to neurological consequences that are more prevalent in male children. Female placentas likely have reduced beta-oxidation capacity and appear to store FA through greater placental esterification, suggesting impaired placenta function and lipid transfer in female placentas of obese mothers.

Maternal-fetal cholesterol transfer in human term pregnancies

OBJECTIVES

The extent to which the human term fetus utilizes cholesterol released from the placenta has remained elusive. Our aims were to estimate the net mass of cholesterol taken up by the uteroplacental unit, released by the placenta and taken up by the fetus. Thereby we aimed to explore the maternal-fetal cholesterol transfer and hypothesized that maternal levels and uteroplacental uptake were correlated to the fetal uptake of cholesterol.

METHODS

A cross-sectional in vivo study of 179 fasting, healthy women with uncomplicated singleton pregnancies. Blood flow in the uterine artery (n = 70) and umbilical vein (n = 125) was measured by Doppler ultrasound. Blood samples from the maternal radial artery, antecubital vein and uterine vein, and the umbilical artery and vein were obtained during cesarean section. Cholesterol was determined enzymatically.

RESULTS

We found a significant uteroplacental uptake (median [Q1,Q3]) of total (3.50 [-36.8,61.1]) and HDL cholesterol (6.69 [-3.78,17.9]) μmol/min, and a fetal uptake of HDL (8.07 [4.48,12.59]), LDL (5.97 [2.77,8.92]) and total cholesterol (13.2 [8.06,21.58]) μmol/min. Maternal cholesterol levels were not correlated to fetal uptake of cholesterol. There was a correlation between uteroplacental uptake of total (rho 0.35, p 0.003) and LDL cholesterol (rho 0.25, p 0.03) and the fetal uptake of LDL cholesterol from the umbilical circulation. The fetal uptake of cholesterol from HDL was higher than from LDL (p < 0.001).

CONCLUSION

Fetal cholesterol uptake is independent of maternal cholesterol levels, but related to the uteroplacental uptake of cholesterol from LDL. This suggests that the placenta influences maternal-fetal cholesterol transfer at term.

Cord blood C-peptide, insulin, HbA1c, and lipids levels in small- and large-for-gestational-age newborns

Background

Small- and large-for-gestational-age (SGA, LGA) newborns are associated with metabolic syndrome in their later life. Cord blood C-peptide, insulin, glycosylated hemoglobin (HbA1c), and lipids levels may be altered in SGA and LGA newborns; however, the results are conflicting. Therefore, this study aimed to determine the effect of cord blood markers on SGA and LGA newborns.

Material/Methods

This was a prospective cohort study and included 2873 term newborns of non-diabetic women. Among these newborns, 83 (2.9%) were SGA, 2236 (77.8%) were appropriate-for-gestational-age (AGA), and 554 (19.3%) were LGA newborns. Cord blood C-peptide, insulin, HbA1c, triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured. The chi-square, Kruskal-Wallis, and Mann-Whitney tests were used to analyze categorical variables and continuous variables, respectively. Multinomial logistic regression analysis was used to determine the independent effect of these variables on SGA and LGA newborns.

Results

Cord serum TG level was significantly higher in the SGA group than in AGA and LGA groups (p<0.05). The LGA group had significantly higher cord serum insulin level than AGA and SGA groups (p<0.05). After adjustment for confounding variables, including maternal age, parity, pre-pregnancy body mass index (BMI), education, annual household income, pregnancy-induced hypertension (PIH), mode of delivery, and newborn sex, high TG and insulin levels remained significantly associated with SGA and LGA newborns, respectively (p<0.05).

Conclusions

High cord serum TG and insulin levels are independently associated with SGA and LGA newborns, respectively.

Lack of relationship between cord serum angiopoietin-like protein 4 (ANGPTL4) and lipolytic activity in human neonates born by spontaneous delivery

BACKGROUND

Ligands of peroxisome-proliferator activated receptors (PPARs), such as non-esterified fatty acids (NEFAs), induce expression of angiopoietin-like protein 4 (ANGPTL4). Recently ANGPTL4 has been reported to be a mediator of intracellular adipose lipolysis induced by glucocorticoids.

OBJECTIVE

To determine the concentrations of ANGPTL4 in cord serum of neonates born by spontaneous vaginal delivery (SVD) and by pre-labor cesarean section (CS) from healthy women, and to relate them to parameters of neonatal lipolytic activity at birth.

MEASUREMENTS

In 54 neonates born by SVD and in 56 neonates born by CS, arterial cord blood was drawn to determine insulin, cortisol, triacylglycerols (TAGs), glycerol, non-esterified fatty acids (NEFAs), individual fatty acids, ANGPTL4, adiponectin, retinol binding protein 4 (RBP4) and leptin.

RESULTS

Birth weight and neonatal fat mass in SVD and CS showed no difference, but the concentrations of glycerol, adiponectin, RBP4, NEFAs and most individual fatty acids were higher in cord serum of neonates born by SVD compared to CS, indicating a higher adipose tissue breakdown in the SVD group. The concentrations of TAG and cortisol were also higher and that of insulin was lower in cord serum of SVD compared to the CS group. However, the concentration in cord serum of ANGPTL4 did not differ between the two groups and no positive correlation with either NEFA or glycerol concentrations were detected.

CONCLUSION

ANGPTL4 is known to stimulate lipolysis in adults, but does not appear to mediate the increased activity in SVD, indicating the presence of different regulatory inputs.

Intrauterine growth restriction is associated with alterations in placental lipoprotein receptors and maternal lipoprotein composition

Among other factors, fetal growth requires maternal supply of cholesterol. Cellular cholesterol uptake is mainly mediated by the LDL receptor (LDL-R) and the scavenger receptor family. We hypothesized that expression levels of key receptors of these families were regulated differently in placentas from IUGR pregnancies with varying degrees of severity. Third-trimester placentas from IUGR pregnancies with (IUGR-S) and without (IUGR-M) fetal hemodynamic changes and from control (AGA) pregnancies were studied. LDL-R, LDL-R-related protein (LRP-1), and scavenger receptor class B type I (SR-BI) mRNA and protein levels were measured. Cholesterol concentration and composition of lipoproteins were analyzed enzymatically and by lipid electrophoresis, respectively, in maternal and umbilical cord blood. LDL-R mRNA levels in IUGR-M were similar to AGA but lower (P < 0.05) in IUGR-S. In contrast, LDL-R protein was twofold (IUGR-M) and 1.8-fold (IUGR-S) higher (P < 0.05) than in the AGA group. LRP-1 mRNA and protein levels were not altered in the IUGR cases. SR-BI mRNA was unchanged in IUGR, but protein levels were lower (P < 0.05) in IUGR-S than in the other groups. Maternal plasma concentrations of LDL cholesterol were higher (P < 0.05) in the AGA group (188.5 +/- 23.6 mg/dl) than in the IUGR-S group (154.2 +/- 26.1). Electrophoretic mobility of the LDL fraction in maternal plasma demonstrated significant changes in migration toward higher values (AGA 0.95 +/- 0.06, IUGR-M 1.12 +/- 0.11, P < 0.001; IUGR-S 1.28 +/- 0.20, P = 0.002). We conclude that LDL-R and SR-BI levels are altered in IUGR pregnancies. These differences were associated with changes in LDL, but not HDL, mobility and cholesterol concentration in maternal circulation.

Adiponectin in umbilical cord blood is inversely related to low-density lipoprotein cholesterol but not ethnicity

CONTEXT

Adiponectin is a recognized protective risk marker for cardiovascular disease in adults and is associated with an optimal lipid profile. The role of adiponectin at birth is not well understood, and its relationship with the neonatal lipid profile is unknown. Because ethnic disparities in cardiovascular risk have been attributed to low adiponectin and its associated low high-density lipoprotein cholesterol (HDL-C), investigation at birth may help determine the etiology of these risk patterns.

OBJECTIVE

Our objective was to investigate the relationship between neonatal adiponectin and lipid profile at birth in two ethnic groups in cord blood.

DESIGN, SETTING, AND PARTICIPANTS

Seventy-four healthy mothers and their newborns of South Asian and White European origin were studied in this cross-sectional study at St. Mary's Hospital, Manchester, United Kingdom.

MAIN OUTCOME MEASURES

Serum adiponectin, total cholesterol, HDL-C, low-density lipoprotein cholesterol (LDL-C), and triglyceride levels were measured in umbilical venous blood at birth and in maternal blood collected at 28 wk gestation.

RESULTS

Cord adiponectin was significantly inversely associated with cord LDL-C (r = -0.32; P = 0.005) but not HDL-C. In a multiple regression analysis, cord LDL-C remained the most significant association of cord adiponectin (beta = -0.13; P < 0.001). We did not find any significant ethnic differences in cord adiponectin or lipids with the exception of triglycerides, which were significantly lower in South Asian newborns (P < 0.05).

CONCLUSION

This is the first report of an inverse relationship between cord adiponectin and LDL-C at birth. In contrast to adult studies, we found no significant association between adiponectin and HDL-C in cord blood. Our results and the strong independent association between adiponectin and HDL-C observed in adult studies suggest a role for adiponectin in lipid metabolism. Ethnic differences in adiponectin may arise after birth.

Cord blood lipoproteins and prenatal influences

PURPOSE OF REVIEW

Blood lipoprotein profiles in early life are known to be related to and predictive of those in adulthood, but little is known about their determinants. Genetic and environmental influences affect cord blood lipoproteins, but how this occurs and the relative contribution of these influences to the overall profile in healthy newborns remains uncertain.

RECENT FINDINGS

This review discusses findings from a range of earlier and more recent studies, and summarizes the key influences on cord blood lipoproteins. In particular, we review the potential contribution of maternal blood total cholesterol levels during pregnancy and the increased maternal transmission in newborns of mothers with diabetes.

SUMMARY

In cord blood, cholesterol levels are lower than in adults and the relative proportion present in HDL as opposed to LDL is much higher. The currently available evidence suggests that several factors influence the composition of cord blood lipoproteins. Although inheritance of major monogenic disorders can affect cord lipids in general, the genetic contribution appears to be minimal, although effects of the proprotein convertase subtilisin/kexine type 9 gene (PCSK9) need fuller exploration in this regard in certain ethnic groups. Evidence is summarized that maternal lipoprotein levels, particularly those due to diet or induced by pregnancy, influence cord lipid levels. Placental insufficiency and other conditions affecting fetal growth and the mode of delivery may also influence cord lipoprotein concentrations. How maternal glucose tolerance during pregnancy affects cord blood lipoproteins remains unclear. In view of increasing evidence that cardiovascular risk may have prenatal antecedents, this would seem to be an important area for further investigation.

Lipoprotein (a) and lipid profile in neonates from mothers with three different types of diabetes mellitus

OBJECTIVES

The metabolic components in neonates may be affected by maternal diabetes mellitus.

DESIGN AND METHODS

To investigate the alterations in lipid metabolism and the possible atherogenic risk, the lipoprotein a (Lp a), apoproteins, lipid profile, glucose concentrations were measured (ELISA, immunodiffusion and enzymatic) in 77 cord blood samples from diabetic and healthy pregnant mothers.

RESULTS

The body weight, cord glucose and both apoproteins were increased in neonates of gestational and noninsulin dependent diabetic (GDM, NIDDM) than in neonates of nondiabetic mothers (NNDM). The Lp (a) was not correlated with the blood glucose and didn't significantly increase in the three neonates groups of diabetic mothers. The apo B/apo A1 and the LDL/HDL ratios were insignificantly increased in relation to the body weight. In neonates of diabetic mothers (NDM), only the blood glucose and Lp (a) differ between both sexes.

CONCLUSION

NDM may have disturbed lipid metabolism, which require special care to them and to their mothers during the prenatal period.

Umbilical cord vascular cell adhesion molecule concentration following labor

OBJECTIVE

This study was designed to determine if VCAM concentrations are increased in serum from neonates delivered vaginally compared to those delivered by cesarean in the absence of labor at term.

METHODS

Serum was collected from umbilical cords immediately after delivery of term uncomplicated pregnancies either prior to onset of labor by scheduled cesarean or following labor. VCAM concentration was determined by commercial ELISA.

RESULTS

Mean VCAM concentration was significantly higher in the laboring (1,106.2 +/- 279 ng/ml) than the nonlaboring group (906.9 +/- 217 ng/ml, P = 0.01).

CONCLUSIONS

Increases in neonatal serum VCAM concentrations may represent a response to enhanced lipid peroxidation and oxidative stress during labor as well as a component of the normal fetal immune response.