Growth in utero and coronary heart disease

Fetal in vivo continuous cardiovascular function during chronic hypoxia

Although the fetal cardiovascular defence to acute hypoxia and the physiology underlying it have been established for decades, how the fetal cardiovascular system responds to chronic hypoxia has been comparatively understudied. We designed and created isobaric hypoxic chambers able to maintain pregnant sheep for prolonged periods of gestation under controlled significant (10% O2) hypoxia, yielding fetal mean P(aO2) levels (11.5 ± 0.6 mmHg) similar to those measured in human fetuses of hypoxic pregnancy. We also created a wireless data acquisition system able to record fetal blood flow signals in addition to fetal blood pressure and heart rate from free moving ewes as the hypoxic pregnancy is developing. We determined in vivo longitudinal changes in fetal cardiovascular function including parallel measurement of fetal carotid and femoral blood flow and oxygen and glucose delivery during the last third of gestation. The ratio of oxygen (from 2.7 ± 0.2 to 3.8 ± 0.8; P < 0.05) and of glucose (from 2.3 ± 0.1 to 3.3 ± 0.6; P < 0.05) delivery to the fetal carotid, relative to the fetal femoral circulation, increased during and shortly after the period of chronic hypoxia. In contrast, oxygen and glucose delivery remained unchanged from baseline in normoxic fetuses. Fetal plasma urate concentration increased significantly during chronic hypoxia but not during normoxia (Δ: 4.8 ± 1.6 vs. 0.5 ± 1.4 μmol l(-1), P<0.05). The data support the hypotheses tested and show persisting redistribution of substrate delivery away from peripheral and towards essential circulations in the chronically hypoxic fetus, associated with increases in xanthine oxidase-derived reactive oxygen species.

In utero origin of sex-related differences in future cardiovascular disease

Background

There are sex differences in the risk of development of cardiovascular disease (CVD). According to the developmental origins of health and disease paradigm (DOHaD), CVD originates in fetal life. This study examines fetal sex differences in cardiovascular development in utero.

Methods

In 1028 pregnant women, we assessed fetal circulation using pulsed wave Doppler examinations between 28 and 34 weeks gestation. To test associations between fetal sex and fetal circulation measurements, linear regression models were used adjusting for fetal size, gestational age, and fetal heart rate.

Results

A higher pulsatility index in the ductus venosus was observed in male fetuses compared to female fetuses (difference 0.02, 95 % CI 0.01; 0.05) with a lower E/A ratio of the tricuspid (difference −0.01, 95 % CI −0.03; −0.00) and mitral (difference −0.02, 95 % CI −0.03; −0.01) valves. This was mainly determined by differences in the E wave of the tricuspid and mitral valves (differences −1.02, 95 % CI −1.81; −0.24 and −1.28, 95 % CI −2.11; −0.46, respectively). Also in males, a lower peak systolic velocity was seen in the pulmonary artery (difference −1.33, 95 % CI −2.63; −0.03) with a similar lower trend regarding peak systolic velocity in the ascending aorta.

Conclusions

Male fetuses exhibit an increased preload and reduced afterload conditions compared to females. While it is difficult to relate these measurements to exact cardiac function, our findings strongly suggest that the known differences in cardiovascular performance between the sexes already start in utero.

Life course models for upper aero-digestive tract cancer

Upper aero-digestive tract (UADT) cancers are collectively cancers of various human body sites, such as the oral cavity, pharynx, oesophagus and larynx. Worldwide, they are the fourth most frequent cancer type and the fourth most common cause of mortality from cancer. Many studies have shown that several chronic diseases, such as cancer, which occur more commonly in later adulthood, are influenced by social and psychological circumstances during birth, childhood, adolescence and early adult life. It is suggested that the build up of problematic circumstances throughout life is the cause of disease, rather than circumstances that happen at one point in time. UADT cancer is a chronic disease of complex multifactorial origin and most of the underlying exposures/risks cannot be considered as individual factors or in isolation, as they act at different levels, which differ from time to time. Thus, life-course epidemiology, rather than drawing false dichotomies between different risk factors of the underlying disease, attempts to integrate biological and social risk processes that cause the chronic disease. It studies how socially patterned exposures during all stages of life--childhood, adolescence and early adult--influence disease risk in adulthood and socio-economic position and hence may account for social inequalities in adult health and mortality. Furthermore, varying health effects, according to the timing or duration of exposure to socio-economic circumstances, may indicate important traces to the causes of cancer. In this paper, we have attempted to draw a conceptual framework on the relationships between socio-economic inequalities, oral health risk factors along the life-course of an individual and incidence of UADT cancer.

Non-coding RNA and DNA as epigenetic biomarkers for pre-eclampsia

The human genome contains a hidden and large layer of biologic information that is not accessible by proteomic or metabolic methods. Insight into the nature, size, function and importance of this information is increasing rapidly. This additional layer of information includes non-coding RNA and DNA and can be retrieved and analyzed using nucleic acids that circulate in the maternal plasma during pregnancy, originate from the developing placenta and provide information on fetal well being. This review explains why, when and how fetal information as carried on and provided by the placental DNA and RNA molecules circulating in the plasma of pregnant women can be explored to understand and to analyze the primary placental processes, that underlie pre-eclampsia and related disorders.

In vivo MRI assessment of placental and foetal oxygenation changes in a rat model of growth restriction using blood oxygen level-dependent (BOLD) magnetic resonance imaging

OBJECTIVES

To evaluate whether changes in BOLD signal intensities following hyperoxygenation are related to intrauterine growth restriction (IUGR) in a rat model.

METHODS

IUGR was induced in pregnant rats by ligating the left vascular uterine pedicle at day 16 of gestation. BOLD MR imaging using a balanced steady-state free-precession (balanced-SSFP) sequence on a 1.5-T system was performed on day 19. Signal intensities (SI) before and after maternal hyperoxygenation were compared in the maternal liver and in control and growth-restricted foetoplacental units (FPUs).

RESULTS

Maternal hyperoxygenation resulted in a significant increase in SI in all regions of interest (P < 0.05) in the 18 rats. In the control group, the SI (mean ± SD) increased by 21 % ± 15 in placentas (n = 74) and 13 % ± 8.5 in foetuses (n = 53). In the IUGR group, the increase was significantly lower: 6.5 % ± 4 in placentas (n = 36) and 7 %± 5.5 in foetuses (n = 34) (P < 0.05).

CONCLUSION

BOLD MRI allows non-invasive assessment of the foetoplacental response to maternal hyperoxygenation in the rat and demonstrates its alteration in an IUGR model. This imaging method may provide a useful adjunct for the early diagnosis, evaluation, and management of human IUGR.

KEY POINTS

• Intra-uterine growth restriction is an important cause of perinatal morbidity and mortality. • Blood oxygen level-dependent MRI non-invasively assesses foetoplacental response to maternal hyperoxygenation. • In the rat, foetoplacental response to maternal hyperoxygenation is altered in IUGR. • Functional MRI may help to assess human IUGR.

Causes and mechanisms of intrauterine hypoxia and its impact on the fetal cardiovascular system: a review

Until today the role of oxygen in the development of the fetus remains controversially discussed. It is still believed that lack of oxygen in utero might be responsible for some of the known congenital cardiovascular malformations. Over the last two decades detailed research has given us new insights and a better understanding of embryogenesis and fetal growth. But most importantly it has repeatedly demonstrated that oxygen only plays a minor role in the early intrauterine development. After organogenesis has taken place hypoxia becomes more important during the second and third trimester of pregnancy when fetal growth occurs. This review will briefly adress causes and mechanisms leading to intrauterine hypoxia and their impact on the fetal cardiovascular system.

Body-composition assessment in infancy: air-displacement plethysmography compared with a reference 4-compartment model

BACKGROUND

A better understanding of the associations of early infant nutrition and growth with adult health requires accurate assessment of body composition in infancy.

OBJECTIVE

This study evaluated the performance of an infant-sized air-displacement plethysmograph (PEA POD Infant Body Composition System) for the measurement of body composition in infants.

DESIGN

Healthy infants (n = 49; age: 1.7-23.0 wk; weight: 2.7-7.1 kg) were examined with the PEA POD system. Reference values for percentage body fat (%BF) were obtained from a 4-compartment (4-C) body-composition model, which was based on measurements of total body water, bone mineral content, and total body potassium.

RESULTS

Mean (+/- SD) reproducibility of %BF values obtained with the PEA POD system was 0.4 +/- 1.3%. Mean %BF obtained with the PEA POD system (16.9 +/- 6.5%) did not differ significantly from that obtained with the 4-C model (16.3 +/- 7.2%), and the regression between %BF for the 4-C model and that for the PEA POD system (R2 = 0.73, SEE = 3.7%BF) did not deviate significantly from the line of identity (y = x).

CONCLUSIONS

The PEA POD system provided a reliable, accurate, and immediate assessment of %BF in infants. Because of its ease of use, good precision, minimum safety concerns, and bedside accessibility, the PEA POD system is highly suitable for monitoring changes in body composition during infant growth in both the research and clinical settings.

Fetal Sheep Brains: Findings at Functional Blood Oxygen Level–Dependent 3-T MR Imaging—Relationship to Maternal Oxygen Saturation during Hypoxia

PURPOSE

To quantify the dependence of the signal intensity (SI) at blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging of fetal sheep brains on maternal oxygen saturation and to investigate the influence of positions of regions of interest (ROIs).

MATERIALS AND METHODS

All experimental protocols were reviewed and approved by the local authorities on animal protection. The brains of singleton fetuses of five anesthetized sheep were subjected to rapid sequences (single-shot echo-planar imaging) of BOLD measurements with a 3-T MR imaging unit. Maternal oxygen saturation and heart rate were recorded continuously. After a normoxic phase, hypoxia was induced by reducing the oxygen in a ventilated gas mixture. ROIs were placed in the cerebrum at a reference level and in the cerebellum. Normalized BOLD SI values were calculated from the mean values of steady-state BOLD SIs at the control (SI(c)) and hypoxic (SI(h)) plateaus as follows: normalized BOLD SI = (SI(h)/ SI(c)) x 100. Normalized BOLD SI values were correlated with maternal oxygen saturation, and linear regression (slope) analysis was performed. Additionally, ROIs were varied in section level and position. Differences in normalized BOLD SI values for ROI placements were calculated by using analysis of variance. A t test was performed to evaluate differences.

RESULTS

Mean maternal oxygen saturation (as the percentage of oxygen in the blood) was 88% (95% confidence interval [CI]: 80%, 96%) in the control period. During hypoxia, it was reduced to 62% (95% CI: 50%, 75%), while fetal normalized BOLD SI decreased to 64% (95% CI: 44%, 85%) in the cerebrum and 56% (95% CI: 32%, 80%) in the cerebellum. Correlations between normalized BOLD SI values and maternal oxygen saturation were as follows: r2 = 0.84 and slope = 1.27 (95% CI: 1.17, 1.36) in the cerebrum and r2 = 0.83 and slope = 1.54 (95% CI: 1.44, 1.63) in the cerebellum. Normalized BOLD SI was 4% lower in the section above the reference level. Variations in normalized BOLD SI for different ROI positions ranged between 0% and 12%.

CONCLUSION

The depletion of oxygen supply is reflected by decreases in fetal brain BOLD SIs that are more distinct in the cerebellum than in the cerebrum. Normalized BOLD SI is influenced only slightly by ROI position.

Relationships among polycyclic aromatic hydrocarbon-DNA adducts, proximity to the World Trade Center, and effects on fetal growth

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by the World Trade Center (WTC) fires and various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. PAH-DNA adducts, or BaP-DNA adducts as their proxy, provide a measure of chemical-specific genetic damage that has been associated with increased risk of adverse birth outcomes and cancer. To learn whether PAHs from the WTC disaster increased levels of genetic damage in pregnant women and their newborns, we analyzed BaP-DNA adducts in maternal (n = 170) and umbilical cord blood (n = 203) obtained at delivery from nonsmoking women who were pregnant on 11 September 2001 and were enrolled at delivery at three downtown Manhattan hospitals. The mean adduct levels in cord and maternal blood were highest among newborns and mothers who resided within 1 mi of the WTC site during the month after 11 September, intermediate among those who worked but did not live within this area, and lowest in those who neither worked nor lived within 1 mi (reference group). Among newborns of mothers living within 1 mi of the WTC site during this period, levels of cord blood adducts were inversely correlated with linear distance from the WTC site (p = 0.02). To learn whether PAHs from the WTC disaster may have affected birth outcomes, we analyzed the relationship between these outcomes and DNA adducts in umbilical cord blood, excluding preterm births to reduce variability. There were no independent fetal growth effects of either PAH-DNA adducts or environmental tobacco smoke (ETS), but adducts in combination with in utero exposure to ETS were associated with decreased fetal growth. Specifically, a doubling of adducts among ETS-exposed subjects corresponded to an estimated average 276-g (8%) reduction in birth weight (p = 0.03) and a 1.3-cm (3%) reduction in head circumference (p = 0.04). The findings suggest that exposure to elevated levels of PAHs, indicated by PAH-DNA adducts in cord blood, may have contributed to reduced fetal growth in women exposed to the WTC event.

Caffeine suppresses the expression of the Bcl-2 mRNA in BeWo cell culture and rat placenta

Chronic caffeine exposure during pregnancy has an effect on fetal growth; however, the adverse effects of caffeine on embryogenesis are not well understood and controversial. We used cDNA microarray technology to determine whether caffeine alters gene expressions in a human cytotrophoblast-like cell line, BeWo. We found that the expression of the B-cell CLL/lymphoma 2 (Bcl-2) gene in BeWo cells was down-regulated by caffeine, suggesting that chronic exposure during the gestational period could exert an influence on embryogenesis. We then focused on the Bcl-2- and Bcl-2-associated X protein gene, Bax, to study the responsive gene expression in BeWo cells as well as placentas of pregnant rats fed a diet supplemented with caffeine (2 mg/100 g body weight) during gestation, and analyzed the gene expressions using LightCycler-based quantitative real-time polymerase chain reaction assays. We found a significantly decreased level of Bcl-2 mRNA expression, which demonstrated the influence of caffeine on placental function.

The effects of the World Trade Center event on birth outcomes among term deliveries at three lower Manhattan hospitals

The effects of prenatal exposure to pollutants from the World Trade Center (WTC) disaster on fetal growth and subsequent health and development of exposed children remain a source of concern. We assessed the impact of gestational timing of the disaster and distance from the WTC in the 4 weeks after 11 September on the birth outcomes of 300 nonsmoking women who were pregnant at the time of the event. They were recruited at delivery between December 2001 and June 2002 from three hospitals close to the WTC site. Residential and work addresses of all participants for each of the 4 weeks after 11 September 2001 were geocoded for classification by place and timing of exposure. Average daily hours spent at each location were based on the women's reports for each week. Biomedical pregnancy and delivery data extracted from the medical records of each mother and newborn included medical complications, type of delivery, length of gestation, birth weight, birth length, and head circumference. Term infants born to women who were pregnant on 11 September 2001 and who were living within a 2-mile radius of the WTC during the month after the event showed significant decrements in term birth weight (-149 g) and birth length (-0.82 cm), compared with infants born to the other pregnant women studied, after controlling for sociodemographic and biomedical risk factors. The decrements remained significant with adjustment for gestational duration (-122 g and -0.74 cm, respectively). Women in the first trimester of pregnancy at the time of the WTC event delivered infants with significantly shorter gestation (-3.6 days) and a smaller head circumference (-0.48 cm), compared with women at later stages of pregnancy, regardless of the distance of their residence or work sites from the WTC. The observed adverse effects suggest an impact of pollutants and/or stress related to the WTC disaster and have implications for the health and development of exposed children.

Ligation of the Uterine Artery and Early Postnatal Food Restriction – Animal Models for Growth Retardation

Intrauterine growth restriction (IUGR) is one of the major causes of short stature in child- and adulthood. The cause of IUGR is unknown, however, an impaired uteroplacental function during the second half of human pregnancy might be an important factor, by affecting the programming of somatotropic axis and leading to postnatal growth failure into adulthood. Two rat models with perinatally induced growth retardation were used to examine the long-term effects of perinatal insults on growth. IUGR rats were prepared from pregnant dams, with a bilateral uterine artery ligation at day 17 of their pregnancy. Since the rat is relatively immature at birth, an early postnatal food restriction model was included as another model to broaden the time window of sensitive period of organogenesis. An individual growth curve was calculated of each animal (n = 813). From these individual growth curves the predicted growth curve for each experimental group was calculated by multilevel analysis. The proposed mathematical model allows us to estimate the growth potentials of these rat models with precision and could provide basic information to investigate the relationships among a number of other variables in future studies. Furthermore, we concluded that both pre- and early postnatal malnutrition leads to irreversible slowing down of postnatal growth.

Child nutrition in developing countries

Malnutrition permeates all aspects of health, growth, cognition, motor and social development of young children in developing countries. More than 50% of deaths in these children can be attributed to malnutrition, most often in conjunction with serious infection. Irreversible and lifelong sequelae prevent children from reaching their full potential. Child survival initiatives and programs have accomplished much to save the lives of children from common and preventable illnesses, but the quality of the survivors' health needs to be improved, with much more attention paid to nutrition of the preschool and school child. Promotion of nutritional health must become an integral part of primary health services, especially for infants, preschoolers, schoolchildren, and women. Promotion of exclusive breastfeeding and appropriate complementary feeding and weaning are essential inputs. A daunting challenge is to improve diet quality through the raising and consumption of small animals by rural subsistence households to enhance maternal and child nutrition. School feeding from preschool onward must be an integral part of education so children are in a condition to learn. An excellent example of such programs is the WHO initiated Integrated Management of Childhood Illness, which integrates nutrition into the care of both sick and well children. The Early Child Development Program initiated by the World Bank and UNICEF has taken hold in many countries. Nutrition outcomes are closely linked with health and education activities starting in the preconception period through pregnancy, lactation, and childhood. Investment in human capital early in life will optimize the growth and social and economic development of children, families, and communities.

Effect of maternal malnutrition and anemia on the endocrine regulation of fetal growth

Fetal growth retardation is a result of a complex pathology caused by multiple factors of fetal, placental, and maternal origin. Hormones and growth factors released as a result of maternal-fetal physiological interactions play an importance role in fetal well being and fetal outcome. Intrauterine Growth Retardation (IUGR) is associated with significant perinatal and childhood morbidity. It is estimated that 13.7 million infants are born annually with IUGR, comprising 11% of all births in developing countries. Both maternal malnutrition and anemia are associated with various degrees of fetal growth retardation. The relationship between decreasing birth weight percentiles and increasing fetal morbidity and mortality has been demonstrated by several investigators and epidemiological studies suggest that IUGR is a significant risk factor for the subsequent development of chronic hypertension, ischemic heart disease, diabetes, and obstructive lung disease in adult life (Barker's Hypothesis). Maternal anemia and/or malnutrition are recognized to be the most frequent cause of IUGR and SGA birth in developing countries like India. In order to investigate adaptive mechanisms by the fetus to overcome the growth disadvantage caused due to maternal nutritional limitations, we examined the quantitative variations in hormonal and growth factor profiles in paired cord blood and maternal samples obtained from neonates born to malnourished and/or anemic mothers. The results of our study show that: 1) The percentage of small for gestational age (SGA) neonates born to malnourished and anemic mothers was significantly higher than those born to mothers who were either malnourished or anemic; 2) Significantly higher levels of GH, PRL, HPL and IGF-1 were observed in the cord blood of neonates born to malnourished and anemic mothers indicative of an adaptive response on part of the fetus to over come an in-utero growth disadvantage; 3) The anoxemia-related fetal perturbations may have unique features that make them distinct from nutrient deficiency-related IUGR. Thus, these novel observations are relevant to the context of the ongoing scientific debate on Barker's hypothesis.

Temperament in young adulthood and later mortality: prospective observational study

STUDY OBJECTIVE

To determine the association between a clinician assessment of temperament in early adulthood and cause specific mortality.

DESIGN

Prospective observational study.

SETTING

Glasgow University.

PARTICIPANTS

9239 male former students aged 16-30 (mean 20.5) years who participated in an ongoing health survey from 1948-68. A physician recorded free text assessment of temperament, which seemed to capture aspects of personality (trait) and mental health (state), was coded into: stable, anxious, schizoid, hypomanic, odd, depressed, immature, hypochondriacal, unstable, and obsessive. Associations between temperament and mortality were investigated using Cox proportional hazards models.

MAIN RESULTS

There were 878 deaths. Most students-8342 (90.3%)-were assessed as stable, the remaining 897 (9.7%) having at least one, and 103 (1.1%) having more than one, temperament type. The second most common temperament was anxiety, recorded in 520 (5.6%) students. In multivariable analyses, having at least one temperament type was associated with increased all cause and stroke mortality, hazard ratios (95% confidence intervals): 1.23 (1.01 to 1.50) and 1.95 (1.06 to 3.59) respectively, compared with stable students. Students with more than one temperament type had higher risk of death from: all causes, 2.05 (1.36 to 3.09); stroke, 3.26 (1.01 to 10.56); and cancer, 2.90 (1.62 to 5.20). Anxiety was positively associated with all cause and cancer mortality, respective hazard ratios: 1.36 (1.07 to 1.72) and 1.51 (1.04 to 2.20). Men labelled hypomanic had increased cardiovascular mortality risk, 1.90 (1.05 to 3.44).

CONCLUSIONS

Markers of early adult psychological distress are associated with increased mortality. Mechanisms underlying these associations require investigation.

Caffeine enhances the expression of the angiotensin II Type 2 receptor mRNA in BeWo cell culture and in the rat placenta

Although chronic caffeine exposure during pregnancy has been shown to affect fetal growth, adverse effects of caffeine on embryogenesis are not only well understood, but also controversial. We have used gene chip technology in an attempt to identify to what extent, if any, caffeine could possibly alter gene expressions in the cytotrophoblast-like cell line BeWo. Few down-regulated genes were found; most of the genes were up-regulated, suggesting that chronic caffeine exposure during the gestational period could exert certain influences on embryogenesis. The highest up-regulated gene expression of BeWo cells by caffeine was angiotensin II type 2 (AT(2)) receptor gene. We focused the genes of the renin-angiotensin system (RAS), angiotensin II type 1 (AT(1)) and AT(2)receptors and angiotensin I converting enzyme, for study on caffeine's responsive gene expression in BeWo cells and in the placentae of pregnant rats that were fed a diet supplemented with caffeine (2 mg/100 g body weight) during gestation, and analysed the gene expressions using RT-PCR and LightCycler system. A significantly increased AT(2)receptor gene expression and a slight decreased AT(1)receptor gene expression demonstrated the caffeine's effect to the placental RAS.

Update on pediatric nutrition: breastfeeding, infant nutrition, and growth

Recent studies continue to point out the critical nature of a patient's nutritional status in helping to determine important health outcomes in pediatrics. We review recent data concerning the composition of breast milk and its adequacy to support infant growth in the first six months of life, as well as trials that support breastfeeding as an important method to delay or reduce the incidence of atopic diseases such as eczema, allergies, and asthma. Studies have also been published that show how physician education and training about breastfeeding can be optimized. Studies showing how nutritional status is measured (using standard anthropometric techniques as well as more modern measures of basal metabolic rate) are highlighted, as well as the role of micronutrient supplementation of patients with the human immunodeficiency virus infection and diarrheal diseases.

Effects of intrauterine and early postnatal growth restriction on hypothalamic somatostatin gene expression in the rat

In the human, intrauterine growth retardation (IUGR) can result in persistent postnatal growth failure, which may be attributable, in part, to abnormal GH secretion. Whether putative alterations in GH secretion are the result of abnormalities intrinsic to the pituitary or reflect changes in the production of GH-releasing hormone or somatostatin (SS) is unknown. We tested the hypothesis that growth failure associated with IUGR or early postnatal food restriction (FR) is caused by a central defect in hypothalamic SS gene expression. Both models displayed persistent growth failure postnatally without any catch-up growth. We measured levels of SS mRNA levels in rats experimentally subjected to IUGR or FR. SS mRNA levels were measured by semiquantitative in situ hybridization throughout development. Levels of SS mRNA in the periventricular nucleus were significantly higher in both male and female IUGR rats in the juvenile and adult stages compared with matched controls (p < or = 0.05). FR was associated with higher SS mRNA levels only in neonatal female rats (p < or = 0.05). These results suggest that intrauterine malnutrition induces a persistent increase in the expression of SS mRNA in the periventricular nucleus, whereas early postnatal FR results in only a transient increase in SS gene expression. Because IGF-I levels were normal in juvenile IUGR and FR rats, central dysregulation of SS neurons does not appear to be the cause of early postnatal growth failure in either model. However, these observations are consistent with the hypothesis that nutritional stress at critical times during development can have persistent and potentially irreversible effects on organ function.

Influence of socioeconomic conditions on growth in infancy: the 1921 Aberdeen birth cohort

OBJECTIVES

To identify environmental influences on infant growth using data from a birth cohort established in 1921.

DESIGN

A longitudinal cohort study.

SETTING

Aberdeen 1921-22.

SUBJECTS

Five hundred and sixteen individuals (263 boys and 253 girls) born in Aberdeen during 1921. Health visitor assessments ranged from two to 40 (47% received at least 10 visits). No records were available for infants who died. Individuals were grouped as those who did not breast feed, those who breast fed initially but not at 6 months, and those who were continuing to breast feed at 6 months.

MAIN OUTCOME MEASURE

Rate of weight gain over the 1st year of life. A random effects model was used to identify environmental factors and conditions contributing to rate of weight gain in the 1st year of life.

RESULTS

Breast feeding rates were about 80% and 50% at 10 days and 6 months, respectively. Breast fed infants were significantly heavier than bottle fed infants at 28 days but this difference disappeared by 12 months. Significant negative effects on rate of weight gain, independent of initial body weight, were found for overcrowding in family homes and maternal parity, whereas social class had no effect.

CONCLUSION

Studies based on historical cohorts that have controlled socioeconomic variables only in terms of social class (derived from parental occupation) may have been subject to residual confounding. Growth in the 1st year of life is likely to reflect a number of environmental influences, some of which may continue to have effects throughout early life and beyond.

Fetal exposure to a maternal low protein diet impairs nephrogenesis and promotes hypertension in the rat

Epidemiological evidence suggests that hypertension and coronary heart disease are programmed by exposure to a poor diet during intrauterine life. It has been proposed that the prenatal environment may exert an adverse effect on the development of the kidney and hence later control of blood pressure. These assertions are supported by animal experiments. In the rat, fetal exposure to a maternal low protein diet is associated with disproportionate patterns of fetal growth and later elevation of blood pressure. Pregnant female rats were fed control (18% casein) or low protein diets throughout pregnancy, or during specific periods. Nephron number was determined at day 20 gestation, full term and 4 weeks of age. Exposure to low protein throughout gestation, or in mid-late gestation increased total nephron number at day 20. By term nephron number was reduced, relative to controls, in rats that were undernourished between days 8-14 or 15-22 gestation. At 4 weeks postnatally rats exposed to low protein throughout fetal life had a reduced (13%) nephron complement and blood pressures 13 mmHg above control animals. Lower renal size and elevated blood pressure persisted to 19 weeks of age, at which time glomerular filtration rate was normal. The data are consistent with the hypothesis that maternal undernutrition may programme the renal nephron number and hence impact upon adult blood pressure and the development of renal disease.

Fetal growth in the baboon during the second half of pregnancy

The normal growth profile of critical fetal organs through the last third of gestation has not been documented in detail in human fetuses or the fetus of any nonhuman primate species. Recent epidemiological studies in human pregnancy suggest that fetal growth plays a major role in the programming of life-long health by modifying cardiovascular, pancreatic, brain, and liver growth. The present study aimed to produce a detailed database of individual organ growth in the fetal baboon in late gestation. Fetal organ weights were obtained from 43 baboon fetuses between 121 and 177 days of gestation. Various organs (brain, heart, kidney, femur, intestines, and spinal cord) showed no sign of slowed growth in late gestation while growth of others (lung, liver, stomach, and bladder) accelerated in late gestation. The fetal adrenal and thymus showed a decrease in growth rate over the final 20 and 10 days of gestation respectively. These observations provide a database that will permit analysis of factors responsible for regulation of normal and altered fetal organ development in this important experimental species.

Description and evaluation of a method based on magnetic resonance imaging to estimate adipose tissue volume and total body fat in infants

Information about body fatness is important during nutritional assessment of infants, but current methods to estimate body composition in vivo are often not applicable in infants. Therefore, a new method based on magnetic resonance imaging (MRI) was developed. This method, which can assess the volume and distribution of adipose tissue (AT) as well as total body fat, was applied in 11 healthy full-term infants. Their total body water was also estimated using the isotope dilution technique. Adipose tissue volume (ATV) was calculated from AT area in 16 images of the body taken by an MRI scanner (1.5 tesla). AT area was assessed using a computer program in which AT criteria was defined by the observer. ATV of the infants was therefore evaluated once by three observers and twice by a fourth observer. The different observers estimated total, s.c., and non-s.c. ATV with a precision that varied between 1.9 and 7.2%, 2.0 and 4.8%, and 4.2 and 40.7%, respectively. Variations during AT area calculations accounted for a large part of the imprecision when assessing total and s.c. ATV. The linear relationship between percent total body water and total ATV in relation to body weight was significant in all evaluations. Although average total ATV varied when estimated by the four observers, there was, within each evaluation, a fairly constant order between infants with respect to their ATV. It is concluded that the MRI procedure represents a useful possibility to assess body fatness in infants.

Compliance with and efficacy of treatment with pravastatin and cholestyramine: a randomized study on lipid-lowering in primary care

OBJECTIVES

Lipid-lowering drugs as 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors and cholestyramine are effective in reducing cardiovascular morbidity both in primary and secondary prevention. Patient compliance is an important determinant of the outcome of therapy. This study was designed to compare compliance with tolerance and lipid-lowering effectiveness of pravastatin and/or cholestyramine in primary care.

DESIGN

Nine hundred and eighty nine women and 1047 men were randomized to treatment at 100 primary-care centres in Sweden. After dietary intervention, an eligible patient was randomly assigned to one of four programs of daily treatment: group Q, 16 g cholestyramine, group QP, 8 g cholestyramine and 20 mg pravastatin, group P20, 20 mg pravastatin or group P40, 40 mg pravastatin.

RESULTS

In group Q, group QP, group P20 and group P40 the reductions in low density lipoprotein (LDL)-cholesterol were 26%, 36%, 27% and 32%. The dose actually taken was 91-95% of the prescribed for the pravastatin treatment groups and 77-88% for the cholestyramine groups. In the pravastatin and cholestyramine groups 76-78% and 44-53%, respectively, completed the trial. Only 8-27% of the patients reached a serum cholesterol target level of 5.2 mmol L-1. There was no difference in lipid-lowering effect between women and men.

CONCLUSION

Pravastatin alone is efficacious and compliance is high, independent of dose. Combined treatment with cholestyramine and pravastatin had a better cholesterol lowering effect (although not statistically significant) than 40 mg pravastatin. Despite this, only 8-27% of the patients actually reached a serum cholesterol level of 5.2 mmol L-1. No unexpected serious adverse events were detected in any of the treatment groups. As predicted, the gastrointestinal disturbances were more common on cholestyramine treatment. These two factors suggest that an increase in the dosage of the HMG-CoA reductase inhibitor may be appropriate. Results from other studies indicate that there also might be other positive effects of statin treatment beyond cholesterol lowering.

Do genetic determinates of ischaemic heart disease imply that prevention may become more difficult?

Favourable changes in environment and lifestyle in the community may lead to a situation in which genetic determinants of ischaemic heart disease assume greater importance. Does this imply that ischaemic heart disease becomes more difficult to prevent? Much of the role of the family history as a risk factor within populations may be explained by new genetic mutations. However, differences between populations are generally attributable to environmental differences. A model of gene-environment interaction implies that individuals or populations with genetic risk markers are both more susceptible and more responsive to environmental changes, including lifestyle and drugs, and thus, may be eminently treatable.

Lipid supply and metabolism in infancy

The rapid growth of young infants is supported by a high dietary fat intake close to 50% of the energy intake, resulting in a high dietary energy density. The adequacy of diets with low fat content during the second half year of life with respect to supporting growth has recently been studied. The digestion of dietary lipids is initiated by gastric lipolysis, which may provide an important contribution to total fat digestion in premature infants. The supply, metabolism and biological effects of long-chain polyunsaturated fatty acids during early development has been the subject of intensive research in recent years in view of potential effects on growth and functional development of visual and neural tissues. Intravenous lipid emulsions are an indispensable part of parenteral nutrition of young children, and efforts are being made to improve the parenteral feeding regimens to meet the metabolic needs for this sensitive group of patients.

Nutrition in early life and cardiovascular disease

Fat-modified diets for children are controversial. Infant nutrition imprints adult lipid metabolism in animals, but evidence is not available for humans. Three intervention trials to reduce total fat, saturated fat and cholesterol intake in children showed small effects on lipid intakes and on serum lipids, but no adverse effects. Serum lipoproteins are associated with coronary artery raised lesions in young adults. Although modifying dietary intakes of children and adolescents appears difficult, changes sufficient to lower plasma cholesterol levels would retard the progression of atherosclerosis and would be safe.

Intrauterine programming of cardiovascular disease by maternal nutritional status

The origins of cardiovascular disease are related to genetic factors, postnatal environmental and behavioral influences, and also the environment experienced in utero. Patterns of disproportionate fetal growth consistent with maternal undernutrition appear to be predictive of later hypertension and coronary heart disease. These findings from epidemiologic studies are strongly supported by animal studies. Experimental models are suggestive of a role for glucocorticoid hormones in the intrauterine programming of cardiovascular function. New understanding of the relationships between maternal diet and the development and maturation of fetal tissues may enable prevention of cardiovascular disease by intervention in early life.

Direct administration of insulin-like growth factor to fetal rhesus monkeys (Macaca mulatta)

A potential treatment for the amelioration of fetal growth failure is insulin-like growth factor-I (IGF-I). To address concerns of safety and efficacy, IGF-I (80 microg/kg; GroPep Pty.) was administered i.p. to healthy rhesus monkey fetuses via ultrasound guidance every other day between gestational days (GD) 110-120 and 130-140 (third trimester; term = approximately GD 165 +/- 10; n = 6). Pregnancies were monitored sonographically, and fetal/maternal blood samples were collected for complete blood counts, immunophenotyping, and biochemical analyses. Blood samples, external measures of the fetus and newborn, and tissue and organ weights were collected at fetal necropsy (GD 150; n = 2) or at term delivery of neonates (GD 160; n = 4). The results of these investigations have shown no evidence of hypoglycemia in the fetus or dam during the course of treatment. Circulating concentrations of fetal, but not maternal, IGF-I increased with treatment (approximately 80 to approximately 1015 ng/ml), and there was no evidence of a change in serum IGF-II or an increase in IGF binding protein-3 compared with historical control values. Fetal lymphocytes and select red cell parameters increased, and a significant elevation in circulating B cells and CD4/CD8 ratios in fetal lymph nodes was shown. Although no changes were detected in body weights, increases in thymic, splenic, and kidney weights and small intestine lengths occurred. Thus, administration of IGF-I to the fetal monkey is safe and results in 1) transient increases in circulating IGF-I, 2) a significant effect on fetal hematopoietic and lymphoid tissues, and 3) an increase in select fetal organ weights and measures. These data suggest that IGF-I may represent a potential candidate for therapeutic treatment of growth-compromised human fetuses in utero.

[Long-term consequences of fetal nutrition]

A large number of animal experimental data indicate that pre- or early postnatal malnutrition can have long-term negative consequences on weight and height, with smaller weight and height in adulthood than predicted on genetics basis. Furthermore, according to the Barker's hypothesis, based on data available from British cohort studies, in utero malnutrition could also result in an increased risk of cardiovascular, endocrine and metabolic diseases in adulthood. There are however discordant data in the literature which invite to be cautious about on this hypothesis, mainly because the role of the socio-economic factors during childhood and adulthood have not been taken into account.