High density lipoprotein particle size distribution in cord blood

Cord blood from 73 full term healthy newborns and blood from adults were analysed for the protein content of high density lipoprotein subclasses separated by gradient gel electrophoresis. Cholesterol and triglyceride concentrations of very low (VLDL), low (LDL) and high (HDL) density lipoproteins were also analysed and newborns had lower concentrations of cholesterol and triglycerides in VLDL, LDL and HDL (p less than 0.001) than adults. The HDL3c subclass, comprising the smallest particles of the HDL particle spectrum, was the major component for newborns and the minor one for adults and was the only lipoprotein fraction with a higher concentration in cord than in adult blood. No sex differences were present for any of the lipoprotein levels of the newborns. Serum cholesterol concentrations were positively correlated to HDL2b (r = 0.49, p less than 0.001) and HDL2a levels (0.42, p less than 0.001), correlations confined to the cholesterol contents of HDL (r = 0.72 and r = 0.67 respectively, both p less than 0.001). Serum triglycerides were inversely correlated to HDL2b and HDL2a levels in male newborns only (r = 0.38 and r = 0.34 respectively, both p less than 0.05). Irrespective of sex, gestational age and birthweight the newborns had 2 typical HDL subclass distributions, characterized by high or low levels of HDL2b and HDL2a. The newborns with high HDL2b and HDL2a levels also had low VLDL lipid levels and high HDL cholesterol concentrations.     

High Density Lipoprotein Particle Size Distribution in Cord Blood

ABSTRACT. Cord blood from 73 full term healthy newborns and blood from adults were analysed for the protein content of high density lipoprotein subclasses separated by gradient gel electrophoresis. Cholesterol and triglyceride concentrations of very low (VLDL), low (LDL) and high (HDL) density lipoproteins were also analysed and newborns had lower concentrations of cholesterol and triglycerides in VLDL, LDL and HDL ( p < 0.001) than adults. The HDL_3c subclass, comprising the smallest particles of the HDL particle spectrum, was the major component for newborns and the minor one for adults and was the only lipoprotein fraction with a higher concentration in cord than in adult blood. No sex differences were present for any of the lipoprotein levels of the newborns. Serum cholesterol concentrations were positively correlated to HDL_2b r = 0.49, p < 0.001) and HD_2a levels (0.42, p < 0.001), correlations confined to the cholesterol contents of HDL ( r = 0.72 and r = 0.67 respectively, both p < 0.001). Serum triglycerides were inversely correlated to HD_2b and HD_2a, levels in male newborns only ( r = 0.38 and r = 0.34 respectively, both p < 0.05). Irrespective of sex, gestational age and birthweight the newborns had 2 typical HDL subclass distributions, characterized by high or low levels of HDL_2b and HDL_2a. The newborns with high HDL_2b and HDL_2a levels also had low VLDL lipid levels and high HDL cholesterol concentrations.     

SERUM LIPIDS AND LIPOPROTEINS AT BIRTH BASED ON A STUDY OF 2815 NEWBORN INFANTS

Abstract. In a consecutive series of 2 815 newborn infants the triglyceride (TG) and cholesterol (CHOL) concentrations were determined in total cord serum and in high density lipoprotein (HDL) containing serum after precipitation of very low (VLDL) and low density lipo proteins (LDL) with heparin manganese chloride. The serum concentrations of TG and CHOL in VLDL+LDL were calculated as the differences between the concentrations in total serum and HDL. The serum concentration of TG totally, in VLDL+LDL and HDL were 0.48, 0.33 and 0.14 mmol/l, respectively, in boys and 0.47, 0.32 and 0.15 mmol/l in girls and of CHOL 1.75, 0.94 and 0.80 mmol/l in boys and 1.88, 1.00 and 0.87 mmol/l in girls. The concentrations of CHOL were significantly higher (p<0.001) in girls than in boys. The distributions of all lipid parameters were skewed to the right, that is towards higher values. Lipoprotein electrophoresis in agarose gel was performed on all serum samples. Patterns compatible with hyperbeta and/or hyperprebeta lipoproteinaemia were observed but no cbylomicrons, broad beta, late prebeta or sinking prebeta lipoprotein bands. The skew distributions of TG and CHOL may be due to primary of secondary hyperlipidaemias.     

Squalene and noncholesterol sterols in serum and lipoproteins of children with and without familial hypercholesterolemia

Squalene and noncholesterol sterols, e.g. lathosterol and plant sterols, the respective markers of cholesterol synthesis and absorption, are transported with cholesterol in serum lipoproteins. Their concentrations and ratios to cholesterol in serum and lipoproteins have not been carefully compared, especially in children and in marked hypercholesterolemia. Thus, we measured these variables with gas-liquid chromatography in 18 children with and 29 without familial hypercholesterolemia, all aged 5-17 y. Concentrations of most noncholesterol sterols were higher in serum, LDL, and intermediate density lipoprotein in the children with than those without familial hypercholesterolemia. Despite accumulation of noncholesterol sterols mainly in LDL (75% in familial hypercholesterolemia and 55% in non-familial hypercholesterolemia, p < 0.001), their ratios were mostly similar in serum and lipoproteins of the two groups. The ratios of squalene and lathosterol were higher in VLDL and intermediate density lipoprotein, whereas in LDL that of lathosterol was lower than the respective serum values in both groups. Absorption marker sterol ratios were highest in HDL in both groups. Thus, even though the ratios of noncholesterol sterols to cholesterol in serum reflect, in general, synthesis and absorption of cholesterol, their ratios in different lipoproteins could give additional information of cholesterol metabolism.     

Lipoproteins and lipids in fetal, neonatal and adult rat serum

Levels of the serum lipoproteins (HDL, LDL and VLDL) and lipids in the fetal, neonatal and pregnant rat were measured using electrophoretic, immunological and biochemical methods. The results were compared to those of the adult rat. In the fetal rat at the end of gestation, the lipoprotein pattern was dominated by LDL (beta-lipoprotein). Fetal HDL (alpha-lipoprotein) occurred at a low concentration and showed a lower proportion of cholesterol and a higher proportion of triglycerides than did HDL in the adult rat serum. VLDL (pre-beta-lipoprotein) was present only at very low concentrations. The lipoprotein pattern of suckling neonatal rats showed rapidly increasing levels of VLDL and LDL, and high serum lipid values during the first 2 weeks after birth. The lipoprotein pattern of the adult rat, with the HDL fraction dominating, was completely developed by about 4 weeks after birth. In rats during late pregnancy, very high serum values were found for VLDL and LDL. High levels of triglycerides associated with these fractions were also seen. The serum lipoprotein development of the fetal and neonatal rat is different from that reported for the pig and man. This focuses the interest on the differences in lipid and lipoprotein metabolism between species during ontogenic development.     

SERUM LIPIDS AND LIPOPROTEINS AT BIRTH BASED ON A STUDY OF 2815 NEWOKN INFANTS

Abstract. In a consecutive series of 2 815 newborn infants the triglyceride (TG) and cholesterol (CHOL) concentrations were determined in total cord serum and in high density lipoprotein (HDL) containing serum after precipitation of very low (VLDL) and low density lipoproteins (LDL) with heparin manganese chloride. The serum Concentrations of TG and CHOL in VLDL+LDL were calculated as the differences between the concentrations in total serum and HDL. By multiple, stepwise, linear regression analysis the influence of various factors during pregnancy and delivery on the serum concentrations of TG and CHOL totally and in lipoproteins was investigated. All investigated factors had only minor or no influence on the lipid concentrations. For CHOL the sex was the variable with the highest coefficient of determination. Infants of diabetic mothers had a higher serum con centration of total and HDL CHOL. Gestational age, Apgar score, duration of labour, maternal blood pressure and dysmaturity showed a positive and birth weight a negative correlation with the TG content in total serum and lipoproteins. These factors did not, how ever, explain all the high serum concentrations of TG and CHOL, either totally or in lipo proteins. It is concluded that other factors are more important than materno-foetal complica tions in determining the lipid and lipoprotein levels at birth.     

Isolation and characterization of lipoprotein profiles in newborns by density gradient ultracentrifugation

Lipoproteins in newborn plasma were isolated from a minimal sample amount (0.3 ml) by a single-step ultracentrifugation in a density gradient, spanning the density range 1.02-1.20 g/ml. After 66 h ultracentrifugation in a swinging-bucket rotor, the content of the tube was eluted and collected in 0.4 ml fractions. Cholesterol and apoproteins AI, AII, and B were assayed in each fraction yielding both the distribution and composition of the very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL2, HDL3). Newborn plasma was characterized by a low amount of triglyceride-poor and cholesterol ester-rich VLDL and high content of HDL2 and HDL3. The VLDL and LDL concentrations increased drastically between 0 and 7 days together with the triglyceride content of the VLDL. At 30 days the lipid composition of VLDL was similar to that of adults, whereas the lipid/protein content remained low both in VLDL and LDL. The composition of HDL2 and HDL3 remained constant during this period, the percentage of HDL2 being higher in newborns than in adults. These compositional changes were reflected in the microviscosity of the lipoproteins, specially in the VLDL fraction.     

Triglyceride and cholesterol concentrations in whole serum and in serum lipoproteins in Reye syndrome.

Triglyceride and cholesterol concentrations in whole serum and in the serum lipoprotein fractions were measured during the course of hospitalization in six patients with Reye syndrome, four of whom survived. Very low density lipoprotein (VLDL) triglycerides were significantly lower on admission than on the last day of hospitalization. However, no VLDL triglyceride value was below the normal range. Triglyceride transport was increased in low density lipoprotein (LDL) and high density lipoprotein (HDL) fractions. LDL and HDL cholesterol concentrations were low on admission and decreased further during hospitalization. The changes in LDL and HDL cholesterol concentrations were more severe among nonsurvivors. No HDL cholesterol was detected in nonsurvivors on the last day of hospitalization. These results suggest that decreased VLDL triglycerides may not play an important role in the development of fatty liver and that decreased LDL and HDL cholesterol concentrations may be of prognostic value in Reye syndrome.     

The effect of feeding human milk and adapted milk formulae on serum lipid and lipoprotein levels in young infants

The effect of feeding with human milk and commercially available milk substitutes was studied in a group of 154 healthy infants during the first 3 months of life by assessment of body weight, body length, head circumference, skinfold thickness, serum lipid and lipoprotein concentrations. Human milk and the different milk formulae have the same energy content (kcal/100 ml) and total fat, total protein and total carbohydrate contents are comparable but they differ in respect of their fatty acid compositions. The various diets were chosen freely by the parents and the newborns were exclusively fed either human milk (n=56), Multival 1 (n=31), Humana 1 (n=33), or Pre Aptamil (n=34). No significant differences in body, weight, body length or head circumference were observed between any of the different dietary groups. Fat storage, as assessed by measurements of skinfold thickness, was significantly less in breast-fed children compared to those on the formula diets. Breast-fed and Pre Aptamil-fed infants had the highest levels of total serum cholesterol, low density lipoprotein (LDL)-cholesterol and LDL. No differences were observed in the levels of total serum triglycerides, very low density lipoprotein (VLDL)- and high density lipoproteins (HDL)-cholesterol, VLDL and HDL. There were no strong correlations between the physical and the biochemical parameters. No indication of an increased risk of developing atherosclerosis was associated with any of the dietary treatments for the duration of this study. However, these investigations support the hypothesis that subtle early nutritional variation can influence mechanisms that regulate lipoprotein and cholesterol levels in later life.Abbreviations VLDL very low density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins - HMG-CoA reductase 3-hydroxy-3-methylglutaryl coenzyme A reductase     

Thyroxine inversely regulates serum intermediate density lipoprotein levels in children with congenital hypothyroidism

BACKGROUND: Although there have been numerous studies on the effects of thyroid hormones on serum lipid profiles, the effects of thyroxine on intermediate how density lipoprotein (IDL) remain uncertain. In an attempt to clarify, this issue, under conditions with very little influence exerted by sex hormones on serum lipid profiles, we studied the relationship between serum thyroid hormone levels and the proportion of serum IDL fractions in children. METHODS: Nineteen children with congenital hypothyroidism and 13 children with non-thyroid diseases were enrolled in this study. Blood samples were taken to measure serum thyroid stimulating hormone, triiodothyronine, free thyroxine (FT4), total cholesterol, high density lipoprotein (HDL) cholesterol, triglyceride and apolipoprotein levels. Lipoprotein fractions, including very low density lipoprotein (VLDL), IDL, low density lipoprotein (LDL) and HDL, were determined by their electrophoretic mobility in a non-denaturing polyacrylamide gel. RESULTS: The proportion of IDL fractions showed a significant inverse correlation with serum FT4 levels and a significant correlation with serum total cholesterol and apolipoprotein B and C-II levels. Serum VLDL, LDL and HDL fractions did not correlate with serum thyroid hormone levels. CONCLUSION: From these results and other studies, we suggest that thyroxine promotes the conversion of IDL into LDL, possibly by its stimulatory effects on hepatic lipase activity.     

Influence of dietary factors on the plasma lipoprotein composition and content in neonates

Previous studies have shown that the cholesterol and apoprotein concentrations in newborn plasma are dependent on the degree of saturation (polyunsaturated/saturated fatty acids ratio) of the dietary fats. In the present study we compare the influence on the lipoprotein patterns of breast-feeding and of two adapted formulae with a similar P/S ratio in 30 infants. The lipoprotein distribution and composition were investigated by density-gradient ultracentrifugation at days 0, 7 and 30.The lipoprotein patterns were quite comparable at 0 and 7 days in the three groups. We found low VLDL and LDL and relatively elevated HDL concentrations with a high percentage of HDL₂. A significant increase of both VLDL and LDL was observed between 0 and 7 days. The VLDL concentration in the breast-fed infants subsequently decreased between 7 and 30 days to a value close to that measured at birth. The infants receiving an adapted formula had significantly higher VLDL and lower LDL at 30 days compared to breast-fed children. HDL concentrations were not significantly different whereas the HDL₂ percentage was significantly lower in the infants receiving the adapted formulae.These data further support the hypothesis that the lipoprotein patterns in infants are sensitive to the type of nutrition and that breast-feeding induces specific lipoprotein patterns compared to adapted milk formulae.Abbreviations VLDL very-low-density lipoproteins - IDL intermediate density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins - FFA free fatty acid - P/S polyunsaturated/saturated fatty acids     

A comparative study of the distribution and fatty acid composition of the lipoproteins in the fetal and maternal plasma of sheep

Fetal plasma contained significantly lower amounts of lipoproteins than the mother. In both mother and fetus, high density lipoprotein (HDL) was the major fraction. Very low density lipoprotein (VLDL) accounted for 12% of total plasma lipid in the mother but only 4% in the fetus. Maternal and fetal plasmas showed similar distributions of lipids in their HDL and low density lipoprotein (LDL) with cholesteryl esters comprising the major lipid of both and LDL having a higher level of triglycerides and lower level of phospholipids than HDL. Low levels of triglycerides were present in fetal VLDL. There were pronounced increases in levels of unsaturated fatty acids with increasing lipoprotein density. In the mother, levels of linoleic acid increased and in the fetus palmitoleic and oleic acids increased. The major saturated fatty acids in the fetal lipoproteins was palmitic acid and in the maternal lipoproteins stearic acid. In contrast to the mother, LDL and HDL of the fetus showed similar fatty acid compositions.     

Lipids, lipoproteins and apolipoproteins AI, AII, B, CII, CIII and E in newborns.

In this study lipid and apolipoprotein patterns were investigated at birth and compared with those of adults. In cord sera, cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol were 38.2, 46.2, 50.5, and 31.9%, respectively, of adult values. Apolipoprotein AII, B and CIII were 48.6, 30.6 and 44.5% of adult values, while apo AI, apo CII and apo E showed values approaching those of adults (63.4, 73.3 and 89.7%, respectively). Also cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol ratios were lower in newborns. In cord sera, lipids were correlated with various apolipoproteins in a surprisingly different way from adult sera. HDL cholesterol was not inversely correlated with triglycerides, and showed a highly positive correlation with apo E, apo CII and apo CIII, which did not correlate with HDL cholesterol in adults. These data supported the presence of significant differences in plasma concentrations and composition of lipoproteins at birth. Therefore HDL, apo CII, and apo E seem to play a different and more important metabolic role in neonatal lipid metabolism.     

Impaired serum lipids and lipoproteins in fetal macrosomia related to maternal obesity

The aim of this work was to determine lipoprotein metabolism alterations in macrosomic newborns and to see whether these lipoprotein abnormalities are parallel or not to those found in their obese or nonobese mothers. Serum lipids, apo A-I, apo B100, lipoproteins (VLDL, LDL, HDL2, and HDL3), and LCAT activity were investigated in obese and nonobese mothers and cord blood of their macrosomic or appropriate-for-gestational-age (AGA) newborns. Serum and VLDL triglyceride concentrations were higher in obese mothers of AGA newborns than in nonobese mothers. Serum triglyceride, VLDL, and apo B100 levels were higher, while serum apo A-I and HDL2 cholesterol concentrations were lower in obese mothers of macrosomic newborns than in the other groups. In their macrosomic newborns, serum lipid, lipoprotein, apo B100, and apo A-I levels were higher as compared with those of other newborns. Macrosomic newborns of nonobese mothers had lipoprotein profiles similar to those in AGA newborns. LCAT activity was similar in both mother groups and in both newborn groups. In conclusion, maternal obesity and fetal macrosomia were associated with lipoprotein abnormalities consistent with high atherogenic risk.     

Serum lipoprotein profile in children with celiac disease

Jejunal mucosa is responsible for the absorption of triglycerides and the production of lipoproteins [chylomicrons, very-low-density lipoprotein (VLDL), high-density lipoprotein (HDL)] and apolipoproteins (B-48, A-I, A-II, A-IV, C-II). Mucosal damage is known to cause fat malabsorption and probably also affects the serum lipid profile. To determine lipoprotein production in states of enterocyte dysfunction, we compared the serum lipid profiles in a group of 12 children with untreated celiac disease (flat jejunal mucosa) with the profiles in a control group of 10 children suffering from other intestinal diseases. Statistically significant differences were found in the following parameters (celiac versus control): plasma levels of triglycerides (70 versus 119 mg/dl), cholesterol content in LDL (107 versus 67.7 mg/dl), protein content in VLDL (6 versus 10 mg/dl), and level of apoprotein A-I (112 versus 140 mg/dl). No significant differences were found between the two groups in the serum levels of total cholesterol, the cholesterol content in VLDL and HDL, the protein content in LDL and HDL, and the level of apoprotein B. Following institution of a gluten-free diet, the lipoprotein profile reverted to normal. These data suggest that the changes in the serum lipoprotein profile in celiac disease are secondary to alterations in enterocyte function and not only a reflection of fat malabsorption.     

Lipoprotein profiles at different stages of the nephrotic syndrome

We investigated lipoprotein profiles in 24 children with normal renal function at different stages of the idiopathic nephrotic syndrome (NS). Four groups of patients were studied: (I) steriod-resistant NS with persistent proteinuria; (II) untreated steroid-sensitive NS during a relapse; (III) steroid-sensitive NS in remission induced by steroid-treatment; (IV) steroid-sensitive NS in long-term remission with-out therapy. Triglycerides (TG), cholesterol (CHOL), and phospholipids (PLP) were measured in plasma as well as in the lipoprotein fractions of very low (VLDL), intermediate (IDL), low (LDL) and high density (HDL). Apoproteins (Apo) AI, AII, B and C-apoproteins were measured in patients of groups I and IV. Results were compared to those obtained in 24 healthy control subjects. All patients with active NS (groups I–III) had significantly elevated CHOL levels. TG and CHOL in the VLDL, IDL, LDL, and CHOL in HDL₂, but not HDL₃ were inversely correlated with the serum albumin level. Patients with active NS had increased concentrations of TG and CHOL in lipoprotein fractions of lower density. Total and fractionated HDL-CHOL was not significantly different from control levels in any group. Patients in group I had significantly reduced Apo AI levels, whereas an increase of Apo AI and Apo AII in HDL₃ and of most C-apoproteins in both HDL fractions was observed in patients of group IV. While changes in HDL apoprotein composition during longterm remission are of yet unknown clinical significance, our data indicate an increased risk of atherosclerosis only in those paediatric patients with persistent steroid-resistant NS.Abbreviations Apo A (B) apoprotein A (B) - CHOL cholesterol - GFR glomerular filtration rate - DHL high density lipoprotein - HLP hyperlipoproteinaemia - IDL intermediate density lipoprotein - LDL low density lipoprotein - MC minimal changes - NS nephrotic syndrome - PLP phospholipids - TG triglycerides - VLDL very low density lipoprotein     

Assessment of feeding different amounts of arachidonic and docosahexaenoic acids in preterm infant formulas on the fatty acid content of lipoprotein lipids

This study evaluated preterm infants of less than 2.3 kg birth weight fed commercial formula (Preemie SMA^®) devoid of arachidonic acid (AA) and docosahexaenoic acid (DHA) and compared this control group with similar infant groups fed one of three formulas containing a range of 0.32-1.1% AA and 0.24-0.75% DHA in the fat component of the formula. An analogous group of infants fed on their mothers' breast milk and a breast milk fortifier was also studied. Individual lipoprotein fractions were isolated from blood samples collected at 12 d of age and after a further 4 wk of feeding. The fatty acid content of individual lipid components, isolated from each lipoprotein fraction was quantitatively determined in order to identify change in marker pools of essential fatty acid. The high density lipoproteins (HDL) and low density lipoproteins (LDL) phospholipid and cholesterol ester fractions contain most of the AA and DHA found in the lipoprotein fractions (total of 0.49% and 0.35%, respectively). Infants fed a formula without AA and DHA showed a reduction in AA level in the phospholipid fraction of all lipoproteins and in the HDL and LDL cholesterol ester fraction. A reduced level of DHA was also observed primarily in the lipoprotein phospholipid fraction in comparison with infants fed breast milk or infant formula containing AA and DHA. Supplementing infant formula with increasing levels of AA and DHA produced a clear dose response in the level of AA found in the HDL and LDL phospholipid fraction. From comparison of the fatty acid levels present in the lipoproteins it appears that a formula level of 0.49% AA and 0.35% DHA provides sufficient levels of these fatty acids to achieve a similar fatty acid content to that of infants fed breast milk for the major lipoprotein fractions examined.     

Anthropometric correlates of lipoprotein profile and blood pressure in high BMI African American children

Objective: To explore the association of anthropometric indices with lipoprotein profile and blood pressure as risk factors of cardiovascular disease, in African American (AA) children. Methods: A cross‐sectional analysis was carried out on children aged 9–13 years with BMI >85th percentile. Height, weight, waist and hip circumferences, % body fat and blood pressure [systolic (sBP) and diastolic (dBP)] were measured. Fasting plasma levels of triglycerides (TG), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol (LDL‐C), intermediate density lipoprotein cholesterol (IDL‐C) and very low‐density lipoprotein cholesterol (VLDL‐C) were analysed. Results: After accounting for age, gender and pubertal status of the child, multiple linear regression models showed that waist circumference and BMIz were strong predictors for lipoprotein variables. In independent analysis, waist circumference and BMI z‐scores were found to be interdependently associated with TG, LDL‐C:HDL‐C ratio, VLDL‐C and sBPz. However, for HDL‐C, TG:HDL‐C ratio and dBPz, waist circumference was independently and more strongly associated with these risk factors than BMI. Conclusion: Waist circumference was a stronger predictor for lipoprotein variables and blood pressure in high BMI AA children than other anthropometric indices, and may be adequate as a screening test to identify children who are at increased risk for cardiovascular disease.     

Apolipoprotein and lipid composition of plasma lipoproteins in neonates during the first month of life

In this study the lipid and apoprotein profiles were investigated in newborns at 0, 7, and 30 days of life. The plasma lipoproteins were separated both by ultracentrifugation and gel filtration in order to compare the patterns obtained by the two techniques. At birth, the apo E concentration is comparable to that measured in adults, but its distribution among lipoproteins is significantly different as more than 80% of the plasma apo E belongs to high-density lipoproteins (HDL). At 7 and 30 days the plasma apo E concentrations are close to the values at birth, but a significant redistribution occurs from HDL to very low-density lipoproteins. By analogy with apo B, the plasma apo CIII concentration is low at birth and increases between 0 and 7 days by a factor of about two. Plasma triglycerides increase significantly during the first week of life so that the apo CIII increase is most pronounced in very low-density lipoproteins. These lipoproteins therefore become enriched in apo E, apo CIII and triglycerides between 0 and 7 days. At birth, a distinct HDL fraction, enriched in apo E, apo AII and cholesterol (HDLE), could be detected. To compensate for the low LDL levels, this HDLE fraction might function as an additional source for cholesterol delivery to peripheral tissues via the apo (B, E) receptor. At later age, low-density lipoprotein synthesis is enhanced, apo E is transferred to very low-density lipoproteins, and cholesterol delivery via the HDLE becomes less important.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of the potential for transfer of lipoprotein-cholesterol across the human placenta

We sought to determine whether evidence exists for the contribution of maternal plasma cholesterol to the fetal plasma cholesterol pool. We found maternal lipoprotein-cholesterol levels at the time of delivery to be significantly higher than those in mixed umbilical cord plasma. The maternal plasma levels of total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol were not correlated to fetal plasma levels of these lipoproteins. There was a weak, but statistically significant, positive correlation between maternal and fetal plasma levels of very low-density lipoprotein (VLDL)-cholesterol. Also, we found a highly significant difference between the levels of HDL-, LDL-, and total cholesterol in umbilical venous and umbilical arterial plasma; venous levels being 7.7-12.8% higher than those in arterial plasma. These data are suggestive that cholesterol derived from maternal plasma can be delivered across the placenta to the fetal compartment in normal pregnancies at term. The contribution of such cholesterol to the fetal plasma cholesterol pool, however, appears to be of minimal quantitative importance in term newborns of women experiencing uncomplicated pregnancies.