The fetal origins of atherosclerosis: maternal hypercholesterolemia, and cholesterol-lowering or antioxidant treatment during pregnancy influence in utero programming and postnatal susceptibility to atherogenesis

Maternal inflammation, growth retardation, and preterm birth: insights into adult cardiovascular disease

The "fetal origin of adult disease Hypothesis" originally described by Barker et al. identified the relationship between impaired in utero growth and adult cardiovascular disease risk and death. Since then, numerous clinical and experimental studies have confirmed that early developmental influences can lead to cardiovascular, pulmonary, metabolic, and psychological diseases during adulthood with and without alterations in birth weight. This so called "fetal programming" includes developmental disruption, immediate adaptation, or predictive adaptation and can lead to epigenetic changes affecting a specific organ or overall health. The intrauterine environment is dramatically impacted by the overall maternal health. Both premature birth or low birth weight can result from a variety of maternal conditions including undernutrition or dysnutrition, metabolic diseases, chronic maternal stresses induced by infections and inflammation, as well as hypercholesterolemia and smoking. Numerous animal studies have supported the importance of both maternal health and maternal environment on the long term outcomes of the offspring. With increasing rates of obesity and diabetes and survival of preterm infants born at early gestational ages, the need to elucidate mechanisms responsible for programming of adult cardiovascular disease is essential for the treatment of upcoming generations.

Heat-shock proteins in cardiovascular disease

Heat-shock proteins (HSPs) belong to a group of highly conserved families of proteins expressed by all cells and organisms and their expression may be constitutive or inducible. They are generally considered as protective molecules against different types of stress and have numerous intracellular functions. Secretion or release of HSPs has also been described, and potential roles for extracellular HSPs reported. HSP expression is modulated by different stimuli involved in all steps of atherogenesis including oxidative stress, proteolytic aggression, or inflammation. Also, antibodies to HSPs may be used to monitor the response to different types of stress able to induce changes in HSP levels. In the present review, we will focus on the potential implication of HSPs in atherogenesis and discuss the limitations to the use of HSPs and anti-HSPs as biomarkers of atherothrombosis. HSPs could also be considered as potential therapeutic targets to reinforce vascular defenses and delay or avoid clinical complications associated with atherothrombosis.

Pathological aspects of lipid peroxidation

Lipid peroxidation (LPO) product accumulation in human tissues is a major cause of tissular and cellular dysfunction that plays a major role in ageing and most age-related and oxidative stress-related diseases. The current evidence for the implication of LPO in pathological processes is discussed in this review. New data and literature review are provided evaluating the role of LPO in the pathophysiology of ageing and classically oxidative stress-linked diseases, such as neurodegenerative diseases, diabetes and atherosclerosis (the main cause of cardiovascular complications). Striking evidences implicating LPO in foetal vascular dysfunction occurring in pre-eclampsia, in renal and liver diseases, as well as their role as cause and consequence to cancer development are addressed.

Changes in serum lipid levels during pregnancy in type 1 and type 2 diabetic subjects

OBJECTIVE

Alterations in maternal lipid metabolism could affect fetal programming and the susceptibility for atherosclerosis in the offspring; therefore, we studied differences in lipid profiles of pregnant women with type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 173 diabetic pregnancies were studied prior to conception (V0), at each trimester (V1-V3), and after delivery and were compared with 137 healthy women at V3.

RESULTS

During gestation, the increase in serum lipid concentrations was less pronounced in type 2 diabetic subjects. At V3, the lipid levels of type 1 diabetic women with normal glucose tolerance were similar but significantly higher then those of type 2 diabetic women. Elevated triglycerides and low HDL cholesterol at V3 were significant predictors for large-for-gestational-age (LGA) newborns.

CONCLUSIONS

Our data suggest smaller changes in serum lipid concentrations during pregnancy in type 2 diabetic mothers. Additionally, we found a positive association between maternal triglycerides and LGA infants independently of chronic glycemic control.

Placental ABCA1 and ABCG1 transporters efflux cholesterol and protect trophoblasts from oxysterol induced toxicity

ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 mediate the efflux of cholesterol and other sterols. Both transporters are expressed on the fetal capillaries of the placenta and are involved in maternal-to-fetal cholesterol delivery. In this study, we report that ABCA1 and ABCG1 are also present on the syncytiotrophoblast, the maternal facing placental membrane. Syncytial ABCA1 expression is apical, suggesting a role in cholesterol efflux to the mother, while ABCG1 is expressed basolaterally indicating transport to the fetus. Silencing of ABCA1 expression in primary trophoblasts in culture, or pharmacological antagonism by glyburide, decreased cholesterol efflux to apolipoprotein A-I (apoA-I) compared to controls, while ABCG1-silencing decreased cholesterol efflux to high density lipoproteins (HDL). In contrast, treatment with endogenous or synthetic LXR alpha/beta ligands such as T0901317 increased ABCA1 and ABCG1 expression and enhanced cholesterol efflux to apoA-I and HDL, respectively, while treatment with pharmacological PPAR-alpha or -gamma ligands was without effect. Trophoblasts transfected with ABCA1 or ABCG1 siRNA were more sensitive to toxic oxysterols substrates (25-hydroxycholesterol and 7-ketocholesterol) compared to mock-transfected cells, while prior treatment with T0901317 reduced oxysterol-mediated toxicity. These results identify syncytial ABCA1 and ABCG1 as important, inducible cholesterol transporters which also prevent placental accumulation of cytotoxic oxysterols.

Effects of maternal obesity on fetal growth and body composition: implications for programming and future health

Since the hypothesis linking low birth weight and poor fetal growth with future risk of cardiovascular disease was first proposed, there has been much interest in the early origins of disease. As rates of obesity increase and as maternal obesity has become common, interest has been directed towards the early origins of obesity. It is likely that a complex interaction of inherited gene effects and in-utero environment may interact in the developing fetus to programme pathways leading to future obesity. It is clear that maternal metabolism is disturbed in pregnancy in obese women, and that offspring of obese mothers have a higher percentage of body fat and are insulin resistant. This review discusses the ideas contributing to the current working concept of obesity programming, and discusses several potential mechanisms that may underlie obesity programming and susceptibility to future metabolic and vascular disease.

Oxidized low-density lipoprotein and ankle-brachial pressure index in patients with clinically evident peripheral arterial disease

OBJECTIVES

To investigate whether oxidized low-density lipoprotein is a suitable predictor of peripheral arterial disease severity. The role of oxidized low-density lipoprotein in the pathogenesis of atherosclerosis has already been investigated. Its relevance as a predictor of the appearance and worsening of coronary arterial disease is also well known. However, the same is not true regarding peripheral arterial disease.

METHOD

Eighty-five consecutive patients with an ankle-brachial pressure index (ABPI) < 0.9 and the presence of either intermittent claudication or critical lower leg ischemia were included. The plasma level of IgG autoantibodies against oxidized low-density lipoprotein was evaluated through an enzyme-linked immunosorbent assay. The results were categorized into quartiles according to the ankle-brachial pressure index (a marker of peripheral arterial disease severity), and significant differences were investigated with the Kruskal-Wallis test.

RESULTS

There was no significant difference between the quartiles for this population (p = 0.33). No correlation was found between the ankle-brachial pressure index and oxidized low-density lipoprotein levels in subjects with clinically evident peripheral arterial disease with a wide range of clinical manifestations.

CONCLUSIONS

Oxidized low-density lipoprotein is not a good predictor of peripheral arterial disease severity.

A maternal high-fat diet is accompanied by alterations in the fetal primate metabolome

OBJECTIVE

To characterize the serum metabolome of a primate model of in utero high-fat exposure.

STUDY DESIGN

Serum from maternal and fetal (e130) macaque monkeys exposed to either a high-fat or control diet were analyzed by gas chromatography-mass spectrometry. Multivariate data analysis was performed to reduce the generated data set. Candidate metabolites were further analyzed for significance by using the analysis of variance and comparative t tests.

RESULTS

Approximately 1300 chromatographic features were detected. Through multivariate data analysis this number was reduced to 60 possible metabolites. With the use of comparative t tests, 22 metabolites had statistical significance (P < .05) over the entire study. By virtue of maternal high-fat diet alone, fetal phenotypic differences are accompanied by altered metabolite concentrations of 7 metabolites (P < .05).

CONCLUSION

In utero high-fat diet exposure is associated with an altered fetal epigenome and parlays a characteristic modification in the fetal metabolite profile.

Impact of maternal undernutrition on diabetes and cardiovascular disease risk in adult offspring

Epidemiological, clinical, and experimental observations have led to the hypothesis that the risk of developing chronic diseases in adulthood is influenced not only by genetic and adult lifestyle factors, but also by environmental factors during early life. Low birth weight, a marker of intrauterine stress, has been linked to predisposition to cardiovascular disease (CVD) and diabetes. The compelling animal evidence and significant human data to support this conclusion are reviewed. Specifically, the review discusses the role of maternal nutrition before and during pregnancy, placental insufficiencies and epigenetic changes in the increased predisposition to diabetes and CVD in adult life. The impact of low birth weight and catch-up growth as they pertain to risk of disease in adult life is also discussed. In addition, adult disease risk in the overnourished fetus is also mentioned. Reference is made to some of the mechanisms of the induction of diabetes and CVD phenotype. It is proposed that fetal nutrition, growth and development through efficient maternal nutrition before and during pregnancy could constitute the basis for nutritional strategies for the primary prevention of diabetes and CVD.

Influence of maternal dysmetabolic conditions during pregnancy on cardiovascular disease

Pathogenic factors associated with maternal hypercholesterolemia, obesity, and diabetic conditions during pregnancy influence fetal development and predispose offspring to cardiovascular disease. Animal models have established cause–effect relationships consistent with epidemiological findings in humans and have demonstrated, in principle, that interventions before or during pregnancy can reduce or prevent pathogenic in utero programming. However, little is known about the mechanisms by which maternal dysmetabolic conditions enhance disease susceptibility in offspring. Identification of these mechanisms is rendered more difficult by the fact that programming effects in offspring may be latent and may require conventional risk factors and inherited genetic co-factors to become clinically manifest. Given the increasing prevalence of maternal risk factors, which is expected to lead to a wave of cardiovascular disease in the coming decades, and the length of prospective studies on developmental programming in humans, greater-than-usual emphasis on experimental models and translational studies is necessary.

Redox modulation of Ca2+ signaling in human endothelial and smooth muscle cells in pre-eclampsia

Pre-eclampsia (PE) is a leading cause of maternal hypertension in pregnancy and is associated with fetal growth restriction, premature birth, and fetal and maternal mortality. Activation and dysfunction of the maternal and fetal endothelium in PE appears to be a consequence of increased oxidative stress, resulting from elevated levels of circulating lipid peroxides. Accumulating evidence implicates reactive oxygen species (ROS) in the pathogenesis of vascular dysfunction in PE, perhaps involving a disturbance in intracellular Ca(2+) signaling. Several ion-transport pathways are highly sensitive to oxidative stress, and the resulting modulation of ion transport by ROS will affect intracellular Ca(2+) homeostasis. We review the evidence that changes in ion transport induced by ROS may be linked with abnormalities in Ca(2+)-mediated signal transduction, leading to endothelial and smooth muscle dysfunction in maternal and fetal circulations in PE. As dysregulation of Ca(2+) signaling in fetal umbilical endothelial cells is maintained in culture and embryonic, fetal, and postnatal development is affected by the cellular redox state, we hypothesize that impaired redox signaling in PE may influence "programming" of the fetal cardiovascular system and endothelial function in adulthood.

Human Endothelial Cells of the Placental Barrier Efficiently Deliver Cholesterol to the Fetal Circulation via ABCA1 and ABCG1

Although maternal–fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas. Maternal cholesterol may enter fetal circulation by traversing syncytiotrophoblast and endothelial layers of the placenta. We hypothesized that endothelial cells (ECs) of the fetoplacental vasculature display a high and tightly regulated capacity for cholesterol release. Using ECs isolated from human term placenta (HPECs), we investigated cholesterol release capacity and examined transporters involved in cholesterol efflux pathways controlled by liver-X-receptors (LXRs). HPECs demonstrated 2.5-fold higher cholesterol release to lipid-free apolipoprotein (apo)A-I than human umbilical vein ECs (HUVECs), whereas both cell types showed similar cholesterol efflux to high-density lipoproteins (HDLs). Interestingly, treatment of HPECs with LXR activators increased cholesterol efflux to both types of acceptors, whereas no such response could be observed for HUVECs. In line with enhanced cholesterol efflux, LXR activation in HPECs increased expression of ATP-binding cassette transporters ABCA1 and ABCG1, while not altering expression of ABCG4 and scavenger receptor class B type I (SR-BI). Inhibition of ABCA1 or silencing of ABCG1 decreased cholesterol efflux to apoA-I (−70%) and HDL 3 (−57%), respectively. Immunohistochemistry localized both transporters predominantly to the apical membranes of placental ECs in situ. Thus, ECs of human term placenta exhibit unique, efficient and LXR-regulated cholesterol efflux mechanisms. We propose a sequential pathway mediated by ABCA1 and ABCG1, respectively, by which HPECs participate in forming mature HDL in the fetal blood.

Maternal low-protein diet or hypercholesterolemia reduces circulating essential amino acids and leads to intrauterine growth restriction

OBJECTIVE

We have examined maternal mechanisms for adult-onset glucose intolerance, increased adiposity, and atherosclerosis using two mouse models for intrauterine growth restriction (IUGR): maternal protein restriction and hypercholesterolemia.

RESEARCH DESIGN AND METHODS

For these studies, we measured the amino acid levels in dams from two mouse models for IUGR: 1) feeding C57BL/6J dams a protein-restricted diet and 2) feeding C57BL/6J LDL receptor-null (LDLR(-/-)) dams a high-fat (Western) diet.

RESULTS

Both protein-restricted and hypercholesterolemic dams exhibited significantly decreased concentrations of the essential amino acid phenylalanine and the essential branched chain amino acids leucine, isoleucine, and valine. The protein-restricted diet for pregnant dams resulted in litters with significant IUGR. Protein-restricted male offspring exhibited catch-up growth by 8 weeks of age and developed increased adiposity and glucose intolerance by 32 weeks of age. LDLR(-/-) pregnant dams on a Western diet also had litters with significant IUGR. Male and female LDLR(-/-) Western-diet offspring developed significantly larger atherosclerotic lesions by 90 days compared with chow-diet offspring.

CONCLUSIONS

In two mouse models of IUGR, we found reduced concentrations of essential amino acids in the experimental dams. This indicated that shared mechanisms may underlie the phenotypic effects of maternal hypercholesterolemia and maternal protein restriction on the offspring.

Post-delivery oxidative stress in women with preeclampsia or IUGR

AIM

To compare oxidative stress in patients with preeclampsia (PE) or intrauterine growth restriction (IUGR) vs. normal pregnancy (controls) during 48 h after delivery.

STUDY DESIGN

Women with singleton pregnancies were recruited immediately after delivery (gestational age >26.0 weeks). Women with PE or IUGR were matched with healthy controls by age, BMI, gestational age and delivery mode. Venous blood samples and urine samples were tested for oxidative stress products 24 h and 48 h after delivery.

RESULTS

Plasma malondialdehyde (MDA) concentration 24 h after delivery was significantly higher in subjects with PE or IUGR (3.41+/-1.14 micromol/L, n=20) than in controls (2.91+/-0.82 micromol/L, n=38) (P=0.04). Urine iPF(2alpha)-VI declined from 24 to 48 h after delivery significantly in controls (P=0.006) and not in subjects with PE or IUGR (P=0.71).

CONCLUSION

Of the markers tested only MDA is indicating higher oxidative stress in women with PE/IUGR than in normal pregnancy and only at 24 h after delivery. No consistent pattern of change in the oxidative stress markers exists between 24-48 h after delivery.

Increased LDL cholesterol and CRP in infants of mothers with type 1 diabetes

BACKGROUND

Proatherogenic stimuli during foetal life may predispose to development of atherosclerosis in adulthood. Elevated plasma low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP) expression is associated with increased risk of atherosclerosis.

METHODS AND RESULTS

In this study, we examined how maternal type 1 diabetes affects foetal plasma LDL cholesterol and CRP. In comparison with healthy mothers, the plasma LDL cholesterol was not increased in the mothers with diabetes, however, the umbilical-cord plasma LDL cholesterol was increased in their infants. CRP was increased in infants of mothers with diabetes and high haemoglobin A1c (HbA1c, > or = 6.2%). Human placenta expresses microsomal triglyceride transfer protein (MTP), which facilitates secretion of apolipoprotein B-containing lipoproteins. Microsomal triglyceride transfer activity was slightly higher (11%) in placentas from mothers with diabetes and HbA1c > or = 6.2% compared with the controls.

CONCLUSION

The results suggest that maternal type 1 diabetes increases the foetal plasma LDL cholesterol and CRP concentration and thus might predispose the offspring to development of atherosclerosis.

Low birth weight and the developing vascular tree: a systematic review

Low birth weight (LBW) is a risk factor for hypertension, stroke and coronary heart disease in adults. Mechanisms underlying cardiovascular disease may therefore be initiated in early life. Studies to investigate the initiating events and emergence of vascular risk markers in infancy and childhood have been an area of particular interest in recent years. The aim of this review is to focus on the early development of the human vascular tree in relation to LBW. Specific characteristics, including endothelial function, intima-media thickness, microvascular density, arterial dimensions and elasticity, will be discussed. LBW due to different causes--poor foetal growth or preterm birth--results in different patterns of altered development of the vascular system, which can already be seen in infancy. Follow-up studies in children and young adults indicate that vascular compromise in many ways persists in those born either small for gestational age or prematurely.

CONCLUSION

LBW is associated with structural and functional changes in the vascular tree, which have implications for cardiovascular health in adult life.

In utero programming of adult vascular function in transgenic mice lacking low-density lipoprotein receptor

OBJECTIVE

The objective of this study was to examine the role of maternal hypercholesterolemia in fetal programming of adult vascular function using transgenic mice lacking the low-density lipoprotein receptor (LDLR).

STUDY DESIGN

Homozygous LDLR knockout mice (B6.129S7-Ldlr(tm1Her)/J, LDLR(-/-KO)) and their wild-type controls (C57BL/6J, LDLR(+/+WT)) were cross-bred to produce 4 litter groups: LDLR(-/-KO), maternally derived heterozygous (LDLR(+/-Mat)), paternally derived heterozygous (LDLR(+/-Pat)) and LDLR(+/+WT). Female and male offspring were killed at 10-12 weeks of age, and carotid arteries were used for in vitro experiments.

RESULTS

The dose responses to phenylephrine were significantly higher in LDLR(-/-KO) and LDLR(+/-Mat) male offspring. The contractile responses to phenylephrine in female mice were significantly increased only in the LDLR(-/-KO) offspring. Maximal Ca(2+) contraction was higher in LDLR(-/-KO) male and female offspring.

CONCLUSION

Despite being genomically similar, heterozygous offspring that developed in a hypercholesterolemic maternal environment had abnormal vascular responses later in life compared with those that developed in a normal environment.

Endothelial function in children with a history of premature prolonged rupture of membranes and bronchopulmonary dysplasia--a pilot study

AIM

To investigate vascular function in children with a neonatal history of generalised inflammation indicated by premature prolonged rupture of membranes (PPROM) and bronchopulmonary dysplasia (BPD).

METHODS

Children born at <or=30 weeks 1994-2000 were investigated at a present age of 6-12 years. Twenty-eight children participated and were divided into two groups with regard to BPD/no BPD (n=15/13) and PPROM/no PPROM (n=10/18). Vascular endothelial function was assessed by acetylcholine (ACh)-induced skin vasodilatation.

RESULTS

Maximum ACh-induced skin perfusion was statistically significantly lower in the PPROM group compared with the non-PPROM group (p=0.045) after adjustment for confounders. We found no association between BPD and maximum ACh-induced skin perfusion (p=0.404), after adjustment for confounders.

CONCLUSION

A neonatal history of prolonged premature rupture of membranes was associated with later impairment of vascular endothelial function in childhood. This association was not observed with BPD. Some forms of perinatal inflammation may be associated with later cardiovascular function.

Lipid peroxidation and decomposition--conflicting roles in plaque vulnerability and stability

The low density lipoprotein (LDL) oxidation hypothesis has generated considerable interest in oxidative stress and how it might affect atherosclerosis. However, the failure of antioxidants, particularly vitamin E, to affect the progression of the disease in humans has convinced even staunch supporters of the hypothesis to take a step backwards and reconsider alternatives. Preponderant evidence for the hypothesis came from animal antioxidant intervention studies. In this review we point out basic differences between animal and human atherosclerosis development and suggest that human disease starts where animal studies end. While initial oxidative steps in the generation of early fatty streak lesions might be common, the differences might be in the steps involved in the decomposition of peroxidized lipids into aldehydes and their further oxidation into carboxylic acids. We suggest that these steps may not be amenable to attenuation by antioxidants and antioxidants might actually counter the stabilization of plaque by preventing the formation of carboxylic acids which are anti-inflammatory in nature. The formation of such dicarboxylic acids may also be conducive to plaque stabilization by trapping calcium. We suggest that agents that would prevent the decomposition of lipid peroxides and promote the formation and removal of lipid hydroxides, such as paraoxonase (PON 1) or apo A1/high density lipoprotein (HDL) might be more conducive to plaque regression.

Atherosclerosis: a redox-sensitive lipid imbalance suppressible by cyclopentenone prostaglandins

Disorders concerning the metabolism of plasma and intracellular lipids are hallmarks of atherosclerosis. However, failures in proper control of intracellular cholesterol balance, rather than simple cholesterol overloading due to augmented uptake, could fuel atherogenesis. Therefore, the understanding of atherosclerosis-associated lipid alterations, which feed an inflammatory microenvironment in the arterial wall, requires the meticulous investigation of several aspects of lipid synthesis, uptake and export from cells. In this regard, the presence of reactive cysteines in transcription factors and key enzymes of lipid metabolism may dictate cholesterol accumulation, and therefore the progression of vascular disease. The strong inhibitory effect of cysteine-reactant anti-inflammatory cyclopentenone prostaglandins (CP-PGs) over atherosclerosis progression in vivo (LipoCardium technology) symbolizes a new concept of atherosclerosis and its treatment. Results from this laboratory and those from other research groups have unraveled a novel facet in prostaglandin research in that CP-PGs may act as redox signals that guide lipid metabolism in atherosclerosis. By modifying enzymes (e.g., HMG-CoA reductase, ACAT and cholesteryl ester hydrolases) and transcription factors (e.g., NF-kappaB and Keap1) involved in inflammation and lipid metabolism, CP-PGs (especially those of A-series) induce pivotal changes in glutathione and lipid metabolism that completely arrest atherosclerosis progression. Hence, pharmacological manipulation of lipid metabolism by CP-PGs may be a novel and invaluable strategy for treating atherosclerosis. Also, a better understanding of why CP-PGs do not resolve inflammation physiologically may explain many unsolved questions and yield insights into atherogenesis and its termination.

Maternal C-reactive protein and developmental programming of atherosclerosis

OBJECTIVE

Maternal hypercholesterolemia during pregnancy enhances the susceptibility to atherosclerosis in their offspring by oxidation-dependent mechanisms. The present study investigated whether maternal C-reactive protein (CRP) level, which is an indicator of inflammation and cardiovascular risk, or smoking, which enhances oxidative stress, predict the in utero programming of atherosclerosis.

STUDY DESIGN

Subsets of patients from the Fate of Early Lesions in Childhood study (156 normocholesterolemic children) were examined at autopsy, classified by maternal cholesterol levels during pregnancy. Maternal CRP level was correlated with maternal cholesterol and aortic atherosclerosis of children.

RESULTS

CRP level was elevated in hypercholesterolemic mothers and showed significant correlation with atherogenesis in children in univariate and multivariate analysis. However, many hypercholesterolemic mothers did not have elevated CRP levels. Smoking only correlated in univariate analysis.

CONCLUSION

CRP level during pregnancy is a predictor of increased atherogenesis in children of hypercholesterolemic mothers, albeit a weaker one than maternal cholesterol. In the presence of hypercholesterolemia, maternal smoking does not further enhance atherogenic programming.

Developmental programming: maternal hypercholesterolemia and immunity influence susceptibility to atherosclerosis

It is increasingly recognized that the in utero environment is an important determinant of adult disease, and extensive epidemiological evidence links dysmetabolic conditions during pregnancy with increased hypertension, cardiovascular disease, and diabetes later in life. The original Barker Hypothesis focused on low birth weight as the primary indicator of postnatal risk, but low birth weight may arise from other, non-metabolic conditions. This has impeded the identification of developmental programming mechanisms. More recently, the focus has shifted to the impact of specific maternal risk factors, such as obesity, metabolic syndrome, and diabetes, on cardiovascular risk in offspring. Inflammation plays a central role in these maternal conditions as well as in offspring atherogenesis, and two key factors that influence inflammation, maternal hypercholesterolemia and maternal immune mechanisms, have been shown to affect the developmental programming of atherosclerosis. Maternal hypercholesterolemia in pregnancy, even if only temporary, is associated with increased fatty streak formation in human fetal arteries and accelerated progression of atherosclerosis in normocholesterolemic children. Conversely, immunization of experimental animals with oxidized low-density lipoprotein cholesterol, an antigen prevalent in atherosclerotic lesions, inhibits the progression of atherosclerosis in the offspring of hypercholesterolemic mothers. These findings indicate it is possible, in principle, to program postnatal immune responses and to reduce atherosclerosis, and potentially other immunomodulated diseases, by targeted maternal immunomodulation.

The contribution of childhood obesity to adult carotid intima-media thickness: the Bogalusa Heart Study

OBJECTIVE

Although obese children are at increased risk for coronary heart disease in later life, it is not clear if the association results from the persistence of childhood obesity into adulthood. We examined the relation of both childhood and adult levels of body mass index (BMI, kg m(-2)) to carotid intima-media thickness (IMT) measured at the (mean) age of 36 years.

DESIGN AND SUBJECTS

Prior to the determination of adult IMT, the 1142 participants had been examined 7 (mean) times in the Bogalusa Heart Study.

MEASUREMENTS

In addition to BMI, levels of lipids, lipoproteins and blood pressure were measured at each examination. Cumulative levels of each risk factor were based on the areas under the individual growth curves calculated using multilevel models for repeated (BMI) measurements. We then examined the relation of these cumulative levels to adult IMT.

RESULTS

Carotid IMT was associated with cumulative levels of BMI in both childhood and adulthood (P<0.001 for each association). Furthermore, the association between childhood BMI and adult IMT persisted, but was reduced, after controlling for adult BMI. Although childhood levels of lipids, lipoproteins and blood pressure were also associated with adult IMT, these associations were not independent of adult levels of these risk factors.

CONCLUSIONS

These results emphasize the adverse effects of elevated childhood BMI levels. In addition to the strong tracking of BMI levels from childhood to adulthood, there appears to be a modest, independent effect of childhood BMI on adult IMT. The prevention of childhood obesity should be emphasized.

Nutrition and Cardiovascular Disease

The major cardiovascular diseases affecting the developed world have at their core atherosclerosis and hypertension, both of which are profoundly affected by diet and can be approached, at least in part, from a nutritional point of view, as can the increasing “epidemic” of obesity. Diet is a multi-component mixture of many nutrients, which may interact with one another. The definitive study of nutrients and their impact on cardiovascular disease can be a daunting enterprise. Many dietary risk factors contribute to these diseases in various environmental and ethnic settings. These risk factors are often in evidence in youth so that preventive measures must be initiated early in life. Although most of the information about nutritional risk factors and cardiovascular disease derives from studies in the developed world, the situation is rapidly evolving toward epidemic proportions in the developing world where a major burden on the economy and health services will be imposed.

Role of lipids and fatty acids in macrosomic offspring of diabetic pregnancy

Diabetic pregnancy frequently results in macrosomia or fetal obesity. It seems that the anomalies in carbohydrate and lipid metabolism in macrosomic infants of diabetic mothers are due to maternal hyperglycemia, which leads to fetal hyperinsulinemia. We have developed a rat model of macrosomic offspring and assessed the onset of obesity in these animals. The macrosomic offspring born to diabetic mothers are prone to the development of glucose intolerance and obesity as a function of age. It seems that in utero programming during diabetic pregnancy creates a "metabolic memory" which is responsible for the development of obesity in macrosomic offspring. We have demonstrated that the metabolism of lipids, and altered anti-oxidant status and immune system are implicated in the etiopathology of obesity in these animals. We have reported beneficial effects of n-3 polyunsaturated fatty acids (PUFAs) in obese animals, born to diabetic dams.

Effect of gestational hypercholesterolaemia on omental vasoreactivity, placental enzyme activity and transplacental passage of normal and oxidised fatty acids

OBJECTIVE

Maternal hypercholesterolaemia during pregnancy increases lipid peroxidation in mothers and fetuses and programs increased susceptibility to atherosclerosis later in life. The objective of this study was to elucidate the role of the placenta in mediating oxidative stress from mother to offspring.

DESIGN

Comparison between normo- and hypercholesterolaemic mothers (n = 36 each) and their children.

SETTING

Obstetric wards, hospitals of the University of Naples and Regione Campania.

POPULATION

Healthy primiparas delivering by caesarean section.

METHODS

Biochemical measurements of oxidative stress and serum leptin in cord plasma and placenta, immunochemistry of placenta microvessels, and vasoreactivity studies were performed.

MAIN OUTCOME MEASURES

Oxidative status (i.e. lipid composition and content of oxidised fatty acids, activity of pro- and antioxidant enzymes, immunohistochemical presence of oxidation-specific epitopes) in maternal and cord blood and in placental tissue, as well as vascular reactivity in omental arteries.

RESULTS

Hypercholesterolaemia during pregnancy was associated with extensive changes in fatty acid composition of both maternal and cord blood lipids, sufficient to alter vasoreactivity of omental vessels. Results also indicated that the placenta is not only subject to substantial oxidative stress, but that it may further increase fetal oxidative stress through changes of pro- and antioxidant enzyme activities.

CONCLUSIONS

The placenta plays an important role in both transmitting and enhancing pathogenic effects of gestational hypercholesterolaemia.

Increased expression of inflammation-related co-stimulatory molecules by HUVECs from newborns with a strong family history of myocardial infarction stimulated with TNF-alpha and oxLDL

BACKGROUND

Recent findings indicate that atherosclerosis, a chronic inflammatory process, might start during childhood. Nevertheless, the expression of inflammation-related molecules of endothelial cell isolated from healthy neonates with a strong family history of myocardial infarction (SFHMI) has been rarely analyzed.

METHODS

Human umbilical vein endothelial cells (HUVECs) from children with SFHMI were assessed for the expression of CD40 and CD40L, in the presence of TNF-alpha and oxLDL. The intracellular content of CD80, CXCL8 and tissue factor by HUVECs stimulated with a CD40 agonist monoclonal antibody as well as monocytes/lymphocyte adhesion to TNF-alpha-stimulated HUVECs was also evaluated.

RESULTS

The basal expression of CD40 and CD40L was higher in SFHMI-positive HUVECs in comparison to controls. TNF-alpha and oxLDL upregulated the expression of CD40 and CD40L in SFHMI versus control HUVECs (p<0.001). The intracellular expression of CXCL8, tissue factor and CD80 was also higher than in controls, and the adhesion of lymphocyte- and monocyte-like cells augmented upon TNF-alpha stimulation.

CONCLUSIONS

It is possible that the modifications observed in the SFHMI-positive HUVECs, all of them relevant to the atherosclerosis process, may lead to early inflammatory reactions, thus contributing to the premature initiation of atherosclerotic lesions in these children.

Lipid and lipoprotein concentrations at age 4. Association with neonatal and parental levels

BACKGROUND AND OBJECTIVE

To study the influence of diet, anthropometrical measurements and neonatal and parental lipoprotein variables on lipoprotein concentrations at age 4.

SUBJECTS AND METHOD

18 neonates with normal serum lipoprotein values (group 1), 19 neonates with high total cholesterol (TC) levels (group 2) and 21 neonates with normal TC but altered levels in other lipids, apolipoproteins, lipoproteins or ratios (group 3) were selected for a follow-up study. Body weight, body mass index (BMI) and the suitability of diet at age 4 for coronary heart disease prevention were evaluated. Multivariable stepwise linear regression analyses were performed for each lipid or lipoprotein parameter at age 4 considering group at birth, diet, neonatal and parental BMI, lipid or lipoprotein parameters.

RESULTS

A large percentage of 4 year-olds had high low density lipoproteins-cholesterol (LDLc) and low high density lipoproteins-cholesterol (HDLc) and followed an unsuitable diet. Prevalence of altered lipoprotein variables, except for TC/HDLc, was similar in the 3 groups. Correlations of birth versus 4 year levels were significant (p = 0.021-0.0001) for all parameters except triglycerides, TC and LDLc. However, all tracking correlations were not significant in group 3. In the multiple regression study, parental and neonatal parameters were retained as explicative variables in many of the models but diet was not retained in any of them. Maternal concentrations were always more explicative than paternal or neonatal ones. Models for TC/HDLc and LDLc/HDLc were the most explicative (both, R2 > 0.578; p < 0.0001).

CONCLUSIONS

Lipoprotein variables at age 4 were more closely associated with progenitors' and neonatal lipoprotein values than BMI or diet.

Mechanisms of Disease: in utero programming in the pathogenesis of hypertension

Nutritional and other environmental cues during development can permanently alter the structure, homeostatic systems, and functions of the body. This phenomenon has been referred to as 'programming'. Epidemiological and animal studies show that programmed effects operate within the normal range of growth and development, and influence the risk of chronic disease in adult life. We review the evidence that these effects include reduced nephron number and compensatory adaptations, which might lead to hypertension, and perhaps accelerate the decline in renal function that accompanies aging. These processes might be exacerbated by programmed changes in vascular structure and function, and alterations in endocrine and metabolic homeostasis. Programmed effects might be initiated as early as the periconceptual phase of development, and could involve epigenetic changes in gene expression or altered stem cell allocation. Better understanding of these processes could lead to the development of novel diagnostic and preventive measures, and to early detection of at-risk individuals. By monitoring blood pressure, weight, and renal function in children, it might be possible to reduce the risk of cardiovascular and renal disease in later life.

Supplementation of n-3 fatty acids during pregnancy and lactation reduces maternal plasma lipid levels and provides DHA to the infants

OBJECTIVE

Docosahexaenoic acid (DHA, 22:6 n-3) is considered an essential fatty acid for the fetus and newborn infant, but the optimal level of supply is not known. We studied the effect of supplementing pregnant and lactating women with marine n-3 polyunsaturated fatty acids (PUFAs) as compared to n-6 PUFAs related to maternal and infant lipid levels.

STUDY DESIGN

Five hundred and ninety pregnant women in weeks 17-19 of pregnancy were recruited. They were given either 10 mL cod liver oil (n-3 PUFAs) or corn oil (n-6 PUFAs) daily until three months after delivery, and 341 women took part in the study until giving birth.

RESULTS

Maternal supplementation with cod liver oil increased the concentration of DHA in maternal as well as infant plasma and umbilical tissue phospholipids, as compared to corn oil. The maternal plasma triacylglycerol increase during pregnancy was less pronounced in women supplemented with cod liver oil as compared to corn oil. The concentration of high-density lipoprotein (HDL)-cholesterol was unchanged during pregnancy in the cod liver oil group, whereas it decreased in the corn oil group, promoting a greater increase in the ratio of total cholesterol/HDL-cholesterol in the corn oil group.

CONCLUSION

Maternal supplementation with n-3 fatty acids during pregnancy and lactation provides more DHA to the infant and reduces maternal plasma lipid levels compared to supplementation with n-6 fatty acids.

Maternal Immunization Programs Postnatal Immune Responses and Reduces Atherosclerosis in Offspring

Maternal hypercholesterolemia during pregnancy increases offspring susceptibility to atherosclerosis by an oxidation-dependent mechanism. The present studies investigated whether maternal immunization with oxidized LDL (OxLDL) before pregnancy protects the fetus from atherogenic in utero programming by maternal hypercholesterolemia. Maternal immunization of NZW rabbits and LDL receptor-deficient mice indeed reduced atherosclerosis in adult offspring by up to 56%, but the protective effect could not be attributed to a reduction of fetal exposure to hypercholesterolemia alone, and even nonspecific immune stimulation with adjuvant only provided some protection. Unexpectedly, offspring of immunized mothers developed increased IgM antibodies to selective OxLDL epitopes and increased IgM-LDL immune complexes, compared with offspring of nonimmunized controls. Even naïve offspring of OxLDL-immunized mothers never exposed to postnatal hypercholesterolemia responded to a one-time OxLDL and KLH challenge with greater OxLDL-specific IgM responses, increased OxLDL-specific IgM-secreting B cells, and more IgM-LDL immune complexes. In contrast, maternal immunization with KLH, a T cell-dependent nonmammalian antigen, did not influence postnatal immune responses. Effects of maternal OxLDL-immunization on offspring B cells and selective antibodies were independent of transplacental passage of maternal immunoglobulins. Results show that maternal immunization with antigens prevalent in atherosclerotic lesions reduces atherogenesis in their offspring by mechanisms that include, but are not limited to, reduced fetal exposure to maternal hypercholesterolemia and lipid peroxidation. More importantly, they demonstrate in principle that maternal adaptive immunity to selective antigens influences postnatal B cell and antibody responses in offspring, and that modulation of in utero immune programming may influence immune-modulated diseases later in life.

Measures of Oxidative Stress

Development of in vivo markers of oxidative stress that are sensitive, specific, reliable, and accurate in reflecting underlying atherosclerotic disease states and prediction of cardiovascular risk and clinical events will be invaluable in the future in clinical medicine. Oxidized low-density lipoprotein (OxLDL) and isoprostanes are emerging plasma biomarkers that hold promise for cardiovascular risk prediction. This article describes the pathophysiology of OxLDL and isoprostanes as potential biomarkers, the rationale behind development of methods to measure OxLDL and isoprostanes, and a detailed description of current methodologies, including advantages and disadvantages of available assays. Clinical investigations consisting of epidemiological, case-control, and prospective studies are reviewed to elucidate the role of these biomarkers in reflecting pathophysiology and risk prediction.

Role of nutrition in the development of the fetal cardiovascular system

Emerging evidence demonstrates that heart disease may originate during fetal development. This review will focus on the role of maternal nutrition in the development of the fetal cardiovascular system. Emphasis will be placed upon the concept that nutritional inadequacies during gestation may be major programming stimuli that alter fetal cardiac, as well as vascular, physiology and predispose an individual to cardiovascular abnormalities in postnatal life. It is hypothesized that this research area will yield new information, resulting in improved fetal nutrition, growth and development through efficient maternal nutrition before and during pregnancy and will form the basis for nutritional strategies for the primary prevention of cardiovascular disease.

Nitric oxide and atherosclerosis: an update

Nitric oxide (NO) is a molecule that has gained recognition as a crucial modulator of vascular disease. NO has a number of intracellular effects that lead to vasorelaxation, endothelial regeneration, inhibition of leukocyte chemotaxis, and platelet adhesion. Endothelium damage induced by atherosclerosis leads to the reduction in bioactivity of endothelial NO synthase (eNOS) with subsequent impaired release of NO together with a local enhanced degradation of NO by increased generation of reactive oxygen species with subsequent cascade of oxidation-sensitive mechanisms in the arterial wall. Many commonly used vasculoprotective agents have their therapeutic actions through the production of NO. L-Arginine, the precursor of NO, has demonstrated beneficial effects in atherosclerosis and disturbed shear stress. Finally, eNOS gene polymorphism might be an additional risk factor that may contribute to predict cardiovascular events. However, further studies are needed to understand the possible clinical implications of these correlations.

C-Reactive Protein and Other Emerging Blood Biomarkers to Optimize Risk Stratification of Vulnerable Patients

Several emerging plasma biomarkers may ultimately prove useful in risk stratification and prognosis of cardiovascular disease. The clinical utility of these biomarkers will depend on their ability to provide a reflection of the underlying atherosclerotic burden or activity; the ability to provide reliable, accurate, and cost-effective information; and the ability to predict future events. High-sensitivity C-reactive protein (hs-CRP) fulfills many, if not all, of these criteria, and blood levels of hs-CRP are now commonly used in clinical practice to improve vascular risk prediction in primary and secondary prevention across all levels of low-density lipoprotein-cholesterol (LDL-C), all levels of the Framingham Risk Score, and all levels of metabolic syndrome. High-sensitivity C-reactive protein may also have clinical relevance as an adjunct to LDL-C for both the targeting and monitoring of statin therapy. Accumulating evidence suggests that several other selected emerging biomarkers may also potentially prove useful in the diagnosis and prognosis of cardiovascular disease. Specifically, data are accumulating on the potential clinical utility of lipoprotein-associated lipoprotein-associated phospholipase A2, myeloperoxidase, oxidized LDL, lipoprotein (a), isoprostanes, and small, dense LDL. This review focuses on hs-CRP and these emerging plasma biomarkers, and their potential diagnostic and prognostic utility in cardiovascular disease. Plasma biomarkers that reflect the clinical potential of atherothrombotic disease may allow more precise risk stratification and prognostication in high-risk populations, and perhaps earlier diagnosis and intervention in patients at risk for or with occult cardiovascular disease.

Oxidized low-density lipoprotein biomarkers in atherosclerosis

The concept that the oxidation of lipoproteins is central in the pathogenesis of atherosclerosis was first reported over 25 years ago, initially by in vitro studies and subsequently through experimental models of atherosclerosis. The innate immune system plays a key role in atherogenesis as manifested by its atherosclerosis-modulating properties, the immunogenicity of oxidized low-density lipoprotein (LDL), and the presence of oxidized LDL autoantibodies in plasma and lesions of humans. In the past 10 years it has been possible to generate monoclonal antibodies to oxidized LDL to directly measure oxidized LDL in plasma. This has led to a rapidly accelerating pace of new reports on the relationship of circulating oxidized LDL and various cardiovascular pathologic processes, which are the focus of this review.

Infection, inflammation, height, and longevity

Using historical data from cohorts born before the 20th century in four northern European countries, we show that increasing longevity and declining mortality in the elderly occurred among the same birth cohorts that experienced a reduction in mortality at younger ages. Concurrently, these cohorts also experienced increasing adult height. We hypothesize that both the decline in old-age mortality and the increase in height were promoted by the reduced burden of infections and inflammation. Thus, early growth and cardiovascular diseases of old age may share infectious and inflammatory causes rooted in the external environment.