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Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, for organ systems are at their most plastic when progenitor cells are proliferating and differentiating. Influences operating at this time can permanently affect their structure and functional capacity, and the activity of enzyme systems and endocrine axes. It is now appreciated that such effects lay the foundations for a diverse array of diseases that become manifest many years later, often in response to secondary environmental stressors. Fetal development is underpinned by the placenta, the organ that forms the interface between the fetus and its mother. All nutrients and oxygen reaching the fetus must pass through this organ. The placenta also has major endocrine functions, orchestrating maternal adaptations to pregnancy and mobilizing resources for fetal use. In addition, it acts as a selective barrier, creating a protective milieu by minimizing exposure of the fetus to maternal hormones, such as glucocorticoids, xenobiotics, pathogens, and parasites. The placenta shows a remarkable capacity to adapt to adverse environmental cues and lessen their impact on the fetus. However, if placental function is impaired, or its capacity to adapt is exceeded, then fetal development may be compromised. Here, we explore the complex relationships between the placental phenotype and developmental programming of chronic disease in the offspring. Ensuring optimal placentation offers a new approach to the prevention of disorders such as cardiovascular disease, diabetes, and obesity, which are reaching epidemic proportions.

The growth of every human fetus is constrained by the limited capacity of the mother and placenta to deliver nutrients to it. At birth, boys tend to be longer than girls at any placental weight. Boy’s placentas may therefore be more efficient than girls, but may have less reserve capacity. In the womb boys grow faster than girls and are therefore at greater risk of becoming undernourished. Fetal undernutrition leads to small size at birth and cardiovascular disorders, including hypertension, in later life. We studied 2003 men and women aged around 62 years who were born in Helsinki, Finland, of whom 644 had hypertension: we examined their body and placental size at birth. In both sexes, hypertension was associated with low birth weight. In men, hypertension was also associated with a long minor diameter of the placental surface. The dangerous growth strategy of boys may be compounded by the costs of compensatory placental enlargement in late gestation. In women, hypertension was associated with a small placental area, which may reduce nutrient delivery to the fetus. In men, hypertension was linked to the mothers’ socioeconomic status, an indicator of their diets: in women it was linked to the mothers’ heights, an indicator of their protein metabolism. Boys’ greater dependence on their mothers’ diets may enable them to capitalize on an improving food supply, but it makes them vulnerable to food shortages. The ultimate manifestation of their dangerous strategies may be that men have higher blood pressures and shorter lives than women.

Adolescence is the period of development that begins at puberty and ends in early adulthood. Most commonly, adolescence is divided into three developmental periods: early adolescence (10-14 years of age), late adolescence (15-19 years of age), and young adulthood (20-24 years of age). Adolescence is marked by physical and sexual maturation, social and economic independence, development of identity, acquisition of skills needed to carry out adult relationships and roles, and the capacity for abstract reasoning. Adolescence is characterized by a rapid pace of growth that is second only to that of infancy. Nutrition and the adolescent transition are closely intertwined, since eating patterns and behaviors are influenced by many factors, including peer influences, parental modeling, food availability, food preferences, cost, convenience, personal and cultural beliefs, mass media, and body image. Here, we describe the physiology, metabolism, and nutritional requirements for adolescents and pregnant adolescents, as well as nutrition-related behavior and current trends in adolescent nutrition. We conclude with thoughts on the implications for nutrition interventions and priority areas that would require further investigation.

Background and Purpose-Women who develop pre-eclampsia in pregnancy are at increased risk of cardiovascular disease. The offspring from pregnancies complicated by pre-eclampsia have higher blood pressures during childhood, but little is known about their long-term health. We hypothesized that pre-eclampsia would lead to an increased risk of cardiovascular disease in the offspring. Methods-We traced 6410 babies born in Helsinki, Finland, from 1934 to 1944. We used the mothers' blood pressure levels and the presence of proteinuria during pregnancy to define pre-eclampsia and gestational hypertension without proteinuria according to modern criteria. Results-Two hundred eighty-four of the pregnancies were complicated by pre-eclampsia (120 with nonsevere and 164 with severe disease) and 1592 by gestational hypertension. The crude hazard ratio for all forms of stroke among people whose mothers had pre-eclampsia was 1.9 (1.2 to 3.0; Pϭ0.01); among people whose mothers had gestational hypertension, it was 1.4 (1.0 to 1.8; Pϭ0.03). There was no evidence that these pregnancy disorders were associated with coronary heart disease in the offspring. Pre-eclampsia, in particular severe disease, was associated with a reduced mean head circumference at birth, whereas gestational hypertension was associated with an increased head circumference in relation to body length. Conclusions-People born after pregnancies complicated by pre-eclampsia or gestational hypertension are at increased risk of stroke. The underlying processes may include a local disorder of the blood vessels of the brain as a consequence of either reduced brain growth or impaired brain growth leading to "brain-sparing" responses in utero.

The generation of new myocytes is an essential process of in utero heart growth. Most, or all, cardiac myocytes lose their capacity for proliferation during the perinatal period through the process of terminal differentiation. An increasing number of studies focus on how experimental interventions affect cardiac myocyte growth in the fetal sheep. Nevertheless, fundamental questions about normal growth of the fetal heart remain unanswered. In this study, we determined that during the last third of gestation the hearts of fetal sheep grew primarily by four processes. 1) Myocyte proliferation contributed substantially to daily cardiac mass gain, and the number of cardiac myocytes continued to increase to term. 2) The (hitherto unrecognized) contribution to cardiac growth by the increase in myocyte size associated with the transition from mononucleation to binucleation (terminal differentiation) became considerable from approximately 115 days of gestational age (dGA) until term (145dGA). Because binucleation became the more frequent outcome of myocyte cell cycle activity after approximately 115dGA, the number of binucleated myocytes increased at the expense of the number of mononucleated myocytes. Both the interval between nuclear divisions and the duration of cell cycle activity in myocytes decreased substantially during this same period. Finally, cardiac growth was in part due to enlargement of 3) mononucleated and 4) binucleated myocytes, which grew in cross-sectional diameter but not length during the last third of gestation. These data on normal cardiac growth may enable a more detailed understanding of the consequences of experimental and pathological interventions in prenatal life.

Placental insufficiency, resulting in restriction of fetal substrate supply, is a major cause of intrauterine growth restriction (IUGR) and increased neonatal morbidity. Fetal adaptations to placental restriction maintain the growth of key organs, including the heart, but the impact of these adaptations on individual cardiomyocytes is unknown. Placental and hence fetal growth restriction was induced in fetal sheep by removing the majority of caruncles in the ewe before mating (placental restriction, PR). Vascular surgery was performed on 13 control and 11 PR fetuses at 110-125 days of gestation (term: 150 +/- 3 days). PR fetuses with a mean gestational Po(2) < 17 mmHg were defined as hypoxic. At postmortem (<135 or >135 days), fetal hearts were collected, and cardiomyocytes were isolated and fixed. Proliferating cardiomyocytes were counted by immunohistochemistry of Ki67 protein. Cardiomyocytes were stained with methylene blue to visualize the nuclei, and the proportion of mononucleated cells and length and width of cardiomyocytes were measured. PR resulted in chronic fetal hypoxia, IUGR, and elevated plasma cortisol concentrations. Although there was no difference in relative heart weights between control and PR fetuses, there was an increase in the proportion of mononucleated cardiomyocytes in PR fetuses. Whereas mononucleated and binucleated cardiomyocytes were smaller, the relative size of cardiomyocytes when expressed relative to heart weight was larger in PR compared with control fetuses. The increase in the relative proportion of mononucleated cardiomyocytes and the relative sparing of the growth of individual cardiomyocytes in the growth-restricted fetus are adaptations that may have long-term consequences for heart development in postnatal life.

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