Developmental change in the position of the fetal human larynx

The position of the mammalian larynx has been shown to be an important determinant in breathing, swallowing, and vocalizing patterns. While the growth of the adult human larynx has been studied extensively, detailed examination of fetal development has not been undertaken. Thus, crucial developmental change in the fetal period and the effects of this change on normal maturation are still unclear. This study has examined the development of the larynx and its topography during the fetal period. Thirty specimens were preserved in 10% buffered formaldehyde solution for a period of 6 weeks, after which mid-sagittal sections were performed. Fetal ages were calculated from femur diaphyseal lengths and ranged from 15 to 29 weeks. Direct measurements were taken to determine the growth and position of the larynx and trachea relative to the vertebral column and soft palate. Results show that the upper and lower levels of the larynx correspond to the basiocciput and the lower border of the third to upper border of the fourth cervical vertebrae, respectively. The epiglottic cartilage was present at 15 weeks. By 21 weeks, the epiglottis was well developed and in close palatal apposition. At 23 to 25 weeks, the epiglottis and soft palate were found to be in full contact. The acquisition of this contact may be related to fetal respiratory viability.     

Prenatal Ethanol Exposure: Changes in Regional Brain Catecholamine Content Following Stress

Abstract: Previous studies have shown that fetal ethanol exposure (FEE) may have long-term effects on the function of catecholaminergic neurons in different regions of the CNS. The present study is the first to examine the effects of FEE on regional brain catecholamine responses following acute stress (a single 60-min restraint stress), repeated stress (single periods of restraint stress on 1, 5, or 10 consecutive days), and recovery from stress (recovery for up to 60 min in the home cage following a single 60-min period of restraint stress). Both male and female offspring from FEE, pair-fed (PF), and ad libitum-fed control (C) groups were tested in adulthood to determine catecholamine content in the cortex, hypothalamus, and hippocampus. A single period of restraint reduced cortical norepinephrine (NE) content in FEE and PF animals compared with that in the cortex of C animals, and reduced hypothalamic NE content in FEE female offspring below that found in animals in all other groups. In contrast, hippo-campal NE content was higher in FEE than in C animals following a single period of restraint; PF animals had intermediate levels of hippocampus NE and did not differ significantly from either FEE or C animals. Following repeated periods of restraint, cortical NE content was lower in FEE than in C animals; PF animals once again had intermediate levels of NE. Importantly, basal (non stressed) NE content did not differ among groups in any brain area examined. In addition, several significant changes in regional brain catecholaminergic responses to acute stress were observed in animals across all treatment groups. Females generally had significantly lower cortical NE levels than males following both single and multiple exposures to restraint. In addition, the cortical NE content decreased below non-stressed levels in all groups following a single restraint period, and remained significantly below basal levels during the 60-min recovery period, whereas the hypothalamic NE content was significantly decreased immediately following the restraint period but showed some recovery toward basal levels by 60 min. There were no significant changes over time in hippocampal NE level or in cortical or hypothalamic dopamine (DA) content following a single restraint stress. Following multiple periods of restraint, hippocampal NE levels were significantly increased and hypothalamic DA levels were significantly decreased in all animals compared with basal levels. These data suggest that the brain noradrenergic response to acute stress is particularly sensitive to the effects of FEE, and that with regard to the hypothalamus, male and female offspring were differentially affected. Furthermore, nutritional effects appear to play some role in mediating the changes in regional brain catecholamine content that are observed. In addition, stress effects on brain catecholamine content across all treatment groups were found to be both region and sex specific.     

Expression of activin subunits and receptors in the developing human ovary: activin A promotes germ cell survival and proliferation before primordial follicle formation

The formation of the essential functional unit of the ovary, the primordial follicle, occurs during fetal life in humans. Factors regulating oogonial proliferation and interaction with somatic cells before primordial follicle formation are largely unknown. We have investigated the expression, localisation and functional effects of activin and its receptors in the human fetal ovary at 14-21 weeks gestation. Expression of mRNA for the activin betaA and betaB subunits and the activin receptors ActRIIA and ActRIIB was demonstrated by RT-PCR. Expression of betaA mRNA increased 2-fold across the gestational range examined. Activin subunits and receptors were localised by immunohistochemistry. The betaA subunit was expressed by oogonia, and the betaB subunit and activin receptors were expressed by both oogonia and somatic cells. BetaA expression was increased in larger oogonia at later gestations, but was low in oocytes within newly formed primordial follicles. Treatment of ovary fragments with activin A in vitro increased both the number of oogonia present and oogonial proliferation, as detected by bromodeoxyuridine (BrdU) incorporation. These data indicate that activin may be involved in the autocrine and paracrine regulation of germ cell proliferation in the human ovary during the crucial period of development leading up to primordial follicle formation.     

Preimplantation antagonism of adrenomedullin action compromises fetoplacental development and reduces litter size

Concentrations of adrenomedullin (ADM) in circulation, the uterus, and corpora lutea (CL) increase during pregnancy. We previously reported a temporal-spatial pattern of ADM level and gene expression of Adm and its receptor components, from early pregnancy through midpregnancy to late pregnancy in rats. Two earlier reports using an in vivo model of ADM antagonism demonstrated the important roles of ADM in the post-implantation period. Treatment with ADM receptor blocker hADM22-52 starting from gestation Day 8 or Day 14 resulted in fetal-placental growth restriction and reduction in litter size. In this study, the endogenous ADM actions were abolished in the preimplantation period by infusing the antagonist for the ADM receptor (hADM22-52) with the osmotic (Alzet) pump from Days 1-4 of pregnancy. We inferred that ADM, acting through the ADM receptor, had critical roles during preimplantation, as brief inhibition of ADM action by hADM22-52 during this period reduced litter size by restricting placental growth and increasing fetal resorption in midpregnancy.     

Estimation and reduction of the radiation dose to the fetus from external-beam radiotherapy

The appearance of a malignant disease during pregnancy is relatively rare. The use of external-beam radiation therapy is limited to non-pelvic tumors which are usually located above the diaphragm. However, supradiaphragmatic radiotherapy unavoidably exposes the fetus to secondary radiation due to head leakage, scatter from the machine and scatter produced inside the patient. This fetal exposure may be associated with an elevated risk for the development of deterministic harmful effects and/or carcinogenesis. The decision about the administration of radiotherapy in a pregnant patient is influenced by the fetal dose which must always be estimated before the patient’s treatment course. The methods employed for fetal dosimetry in external-beam radiotherapy are described in this review study. Direct dose measurements using thermoluminescent dosemeters or large ionization chambers placed on physical phantoms may be used. Monte Carlo simulations on computational phantoms may also provide accurate fetal dose calculations. The physical and/or computational phantoms need to simulate the full-scatter geometry of the pregnant patient. Typical fetal dose values attributable to radiation therapy for brain tumors, head and neck cancer, breast carcinoma and Hodgkin lymphoma at the first, second and third trimesters of gestation are presented. The effectiveness of different shielding devices for fetal dose reduction in radiotherapy is discussed. The effect of the dimensions and setup of the shielding material on the radiation dose received by the fetus is described. Moreover, practical methods for reducing the fetal dose by selecting the appropriate irradiation parameters are presented.     

Carry-over effects of embryonic acid conditions on development and growth of Rana temporaria tadpoles

1. Conditions experienced during the early stages of development may have carry‐over effects on performance during later life. The egg laying period and embryonic development of temperate and boreal zone amphibians often coincides with peak acidity resulting from spring snow‐melt, but the effects of acid conditions during embryonic stage on subsequent performance are unknown. 2. We investigated the potential carry‐over effects of acidity during the embryonic stage on performance up to metamorphosis in the common frog (Rana temporaria) tadpoles. There were four combinations of acid (4.5) and neutral (7.5) pH treatments applied to the egg and larval stages in a factorial laboratory experiment. In addition, we studied the difference in embryonic and larval tolerance of acidity between two populations originating from circumneutral (pH 6.6) and acidic conditions (pH 4.8). 3. The effects of acid conditions during the embryonic stage were sublethal, as indicated by delayed development and reduced size. Under acid conditions, tadpoles that had been raised in neutral water as embryos at first grew more slowly than tadpoles raised under acid conditions as embryos. At metamorphosis, no effects of embryonic acidity were detectable indicating that tadpoles were able to compensate fully for the initial reduction in growth. 4. Acid conditions during the larval period had a strongly negative effect on survival, size and age at metamorphosis. The amount of food consumed was lower under acid conditions, suggesting that reduced food consumption was at least partly responsible for the negative effects. 5. Although the two populations differed in the length of larval period, there was no indication of a differential response to the treatments in any of the metamorphic traits studied. 6. These results suggest that, although moderate acid conditions during embryonic development affect growth and development negatively, this influence does not persist after conditions have returned to normal. However, even moderately acid conditions during the larval period may have a strong negative influence on survival and performance of the tadpoles.     

Glucocorticoid programming of adult disease

Fetal exposure to elevated levels of glucocorticoids can occur naturally when maternal glucocorticoids are elevated in times of stress or when exogenous glucocorticoids are administered. Epidemiological studies and animal models have shown that, whereas short-term benefits may be associated with fetal glucocorticoid exposure, long-term deleterious effects may arise. This review compares the effects of exposure to natural versus synthetic glucocorticoids and considers the ways in which the timing of the exposure and the sex of the fetus may influence outcomes. Some of the long-term effects of glucocorticoid exposure may be explained by epigenetic mechanisms.     

Quantification of risk from fetal exposure to diagnostic ultrasound

Biomedical ultrasound may induce adverse effects in patients by either thermal or non-thermal means. Temperatures above normal can adversely affect biological systems, but effects also may be produced without significant heating. Thermally induced teratogenesis has been demonstrated in many animal species as well as in a few controlled studies in humans. Various maximum ‘safe’ temperature elevations have been proposed, although the suggested values range from 0.0 to 2.5° C. Factors relevant to thermal effects are considered, including the nature of the acoustic field in situ, the state of perfusion of the embryo/fetus, and the variation of sensitivity to thermal insult with gestational stage of development. Non-thermal mechanisms of action considered include acoustic cavitation, radiation force, and acoustic streaming. While cavitation can be quite destructive, it is extremely unlikely in the absence of stabilized gas bodies, and although the remaining mechanisms may occur in utero, they have not been shown to induce adverse effects. For example, pulsed, diagnostic ultrasound can increase fetal activity during exposure, apparently due to stimulation of auditory perception by radiation forces on the fetal head or auditory structures. In contrast, pulsed ultrasound also produces vascular damage near developing bone in the late-gestation mouse, but by a unknown mechanism and at levels above current US FDA output limits. It is concluded that: (1) thermal rather than nonthermal mechanisms are more likely to induce adverse effects in utero, and (2) while the probability of an adverse thermal event is usually small, under some conditions it can be disturbingly high.     

Correcting the short-term effect of food deprivation in a damselfly: mechanisms and costs

1. Mass at emergence is a life-history trait strongly linked to adult fitness. Therefore, when faced with transient food shortage in the larval stage, mass-correcting mechanisms are common. 2. These correcting mechanisms may carry costs with them. On one hand, these costs may be overestimated because they can be confounded with the direct effects of the transient food shortage itself. On the other hand, costs may be underestimated by ignoring physiological costs. Another largely neglected topic is that correcting mechanisms and costs may critically depend upon other stressors that often co-occur. 3. Here, we identify the mass-correcting mechanisms and their associated costs at emergence in the damselfly Coenagrion puella, after being stressed by a transient period of starvation and a subsequent exposure to pesticide stress during the larval stage. We introduce path analysis to disentangle direct costs of starvation and the mass-correcting mechanisms in terms of immune response. 4. As predicted, we found no differences in mass at emergence. Starvation directly resulted in a costly delayed emergence and a decreased immune response at emergence. Mass-correcting mechanisms included a prolonged post-starvation period, reduced mass loss at emergence and compensatory growth, although the latter only in females under pesticide stress. 5. The mass-correcting mechanisms were associated with beneficial effects on investment in immune response, but only in the absence of pesticide stress. Under pesticide stress, these beneficial effects were mostly undone or overruled, resulting in negative effects of the mass-correcting mechanisms in terms of immune response. 6. Our results stress the importance of and introduce a statistical way of disentangling direct costs of starvation and the mass-correcting mechanisms themselves, and the importance of including physiological endpoints in this kind of studies.     

胎肝干细胞的分离、培养与鉴定

目的体外扩增培养大鼠胎肝干细胞,研究其形态、生物学特性及表面标志物,探讨胎肝干细胞的性质。方法分离培养胎龄12-16d的胎肝细胞,SABC法检测原代、传代后及细胞克隆中的肝干细胞特异表面标志物OV-6、CK-19及nestin的表达。结果原代、传代培养的胎肝细胞部分表达OV-6、CK-19及nestin;培养3d开始出现小细胞团,1个月即形成肉眼可见的细胞集落,5-7d传代一次;细胞克隆几乎全部为干细胞标志阳性细胞。结论胎肝干细胞可通过克隆筛选法进行体外扩增,胎肝内存在nestin阳性干细胞,可能是一种更为原始的干细胞,在胚胎发育中起重要作用。     

Maternal age and parity influence ultrasonographic measurements of fetal growth in Dutch Warmblood mares

Ultrasonographic examination of the equine fetus in mid-late gestation is usually performed only if there are concerns about fetal or maternal health. Even then it is difficult to determine whether development is ‘normal’ for gestational age because the reference values include considerable error margins. This study examined maternal factors that influence fetal growth with the aim of producing more precise late gestation fetal growth curves for Dutch Warmblood horses. Fetal development was monitored at 2-week intervals from day 100 of gestation until term in 32 mares ranging from 4 to 18 years in age; seven of the mares were primiparous. Transrectal and/or transabdominal ultrasonographic measurement of the fetal eye orbit, cranium, aorta, heart rate and of the combined thickness of uterus and placenta (CTUP) were performed using a portable ultrasound machine equipped with 6 MHz linear and 3.5 MHz curved array probes.During days 100–250 of gestation, the CTUP was thicker in primiparous than multiparous mares (p < 0.05). After day 220 the maximum cross-sectional area, but not diameter, of both the eye orbit and cranium were also greater in primiparous than multiparous mares (p < 0.05). Fetal aorta diameter was not influenced by parity but was affected by maternal age, being smaller in mares ≥15 years of age than younger animals (p < 0.05). Only biparietal cross-sectional surface area and aorta diameter increased linearly throughout late gestation. However, even allowing for the effects of parity and maternal age, the late gestational variation in fetal size is such that serial measurements may be required to definitively identify abnormal development.     

Effects of early resource limitation and compensatory growth on lifetime fitness in the ladybird beetle (Harmonia axyridis)

Acceleration of growth following a period of diet restriction may result in either complete or partial catch-up in size. The existence of such compensatory growth indicates that organisms commonly grow at rates below their physiological maxima and this implies a cost for accelerated growth. We examined patterns of accelerated growth in response to temporary resource limitation, and assayed both short and long-term costs of this growth in the ladybird beetle Harmonia axyridis. Subsequent to the period of food restriction, accelerated growth resulted in complete compensation for body sizes, although we observed greater larval mortality during the period of compensation. There were no effects on female fecundity or survivorship within 3 months of maturation. Females did not discriminate against males that had undergone compensatory growth, nor did we observe effects on male mating behaviour. However, individuals that underwent compensatory growth died significantly sooner when deprived of food late in adult life, suggesting that longer-term costs of compensatory growth may be quite mild and detectable only under stressful conditions.     

An assessment of direct and indirect effects of climate change for populations of the Rocky Mountain Apollo butterfly (Parnassius smintheus Doubleday)

Abstract Climate change is occurring and insects are responding. Current challenges for ecologists and managers are predicting how organisms will respond to continuing climate change and determining how to mitigate potential negative effects. In contrast to broad scale predictions for climate change involving the distribution of species, in this article we highlight the many ways in which local populations of the Rocky Mountain Apollo butterfly (Parnassius smintheus Doubleday) are predicted to respond to climate change. Using experimental and observational data collected over the past 15 years, we detail both direct and indirect effects. In addition, we identify limitations in our knowledge restricting the ability to predict how populations will respond to climate change. Some changes, such as warmer winter temperatures, may have beneficial effects; however, most of the effects of climate change will be detrimental. Variability in snow cover during the overwintering period and habitat loss due to forest encroachment have the largest potential negative effects.     

Proteomic analysis of fetal programming‐related obesity markers

The objectives of this study were to analyze fetal programming in rat brain using proteomic analysis and to identify fetal programming‐related obesity markers. Sprague–Dawley rats were divided into four feeding groups: (i) the Ad Libitum (AdLib)/AdLib group was given a normal diet during pregnancy and the lactation period; (ii) the AdLib/maternal food restriction group (FR) was subjected to 50% FR during the lactation period; (iii) the FR/AdLib group was subjected to 50% FR during pregnancy; and (iv) the FR/FR group was subjected to 50% FR during pregnancy and the lactation period. Offspring from each group were sacrificed at 3 weeks of age and whole brains were dissected. To obtain a maximum number of protein markers related to obesity, 2DE and Pathway Studio bioinformatics analysis were performed. The identities of the markers among the selected and candidate proteins were confirmed by Western blotting and immunohistochemistry. Proteomic and bioinformatics analyses revealed that expression of ubiquitin carboxy‐terminal hydrolase L1 (UCHL1) and Secernin 1 (SCRN1) were significantly different in the FR/AdLib group compared with the AdLib/AdLib group for both male and female offspring. These findings suggest that UCHL1 and SCRN1 may be used as fetal programming‐related obesity markers.     

Development of ATPase-positive,immature Langerhans cells in the fetal mouse epidermis and their maturation during the early postnatal period

Summary The development and maturation of Langerhans cells during the differentiation of skin was studied in mice from fetal day 13 to adult using 3 indices: (1) ATPase activity; (2) ultrastructure; and (3) quantitative evaluation of the cell population.ATPase-positive Langerhans cells appeared in the epidermis at first at fetal day 16, and they increased in number in the differentiating epidermis during the late fetal period. The earliest appearance of Birbeck granules was at postnatal day 4. Cored tubules were also formed in the Langerhans cells in the dermis at around the same age. The cells containing Birbeck granules or cored tubules are considered to be mature Langerhans cells. In the Langerhans-cell lineage, those cells in the epidermis at stages earlier than postnatal day 4 and not yet containing specific organelles are considered to be immature Langerhans cells. These immature Langerhans cells can be identified ultrastructurally in the epidermis at fetal day 16, coinciding with the appearance of ATPase-positive cells. The increase in the number of immature Langerhans cells during the perinatal period was shown by quantitative analysis of nuclear density and relative Langerhans-cell area on the electron micrographs.It is concluded that ATPase is a marker of the Langerhans-cell lineage from the early development stages, while Birbeck granules and cored tubules are markers that identify mature Langerhans cells in electron micrographs.     

Maternal essential metals,thyroid hormones,and fetal growth: Association and mediation analyses in Chinese pregnant women

BackgroundEssential metals play critical roles in fetal growth and development, but results from human studies are inconsistent. Additionally, whether maternal thyroid hormone (TH) levels mediate the associations between essential metals and fetal growth remains unknown.MethodsData for analysis were extracted from the Information System of Guangdong Women and Children Hospital between January 2017 and December 2019. Maternal levels of essential metals [copper (Cu), zinc (Zn), magnesium (Mg), and iron (Fe)] and THs were measured at the second trimester. Multivariate linear models were introduced to evaluate the potential associations between maternal essential metals, thyroid functions, and fetal growth, and the possible mediation effects of thyroid functions were explored in the median analyses.ResultsA total of 4186 mother-infant pairs were included in the present study. Maternal Fe levels were found to significantly increase birth weight in 272.91 g (95 % CI: 15.59, 530.22) among anemia group. Maternal Cu levels were positively associated with increased free triiodothyronine/free thyroxine ratio (FT3/FT4). Negative associations of Fe and Mg levels with thyroid-stimulating hormone (TSH) concentrations were observed, accompanied with the positive associations in relation to FT3, FT4 and FT3/FT4 ratio. Mediation analyses suggested that 72.01 % of the associations between Fe levels and birth length might be mediated by FT3 levels. Additionally, 25.85 % of the Cu-birth length association and 44.53 % of the Fe-birth length association could be explained by FT3/FT4 ratio.ConclusionOur findings suggest that maternal Cu, Mg, and Fe levels can alter TH concentrations, and maternal FT3 and FT3/FT4 ratio might be potential mediators on the developmental effects of Cu and Fe levels.     

Selection against late emergence and small offspring in Atlantic salmon (Salmo salar)

Timing of breeding and offspring size are maternal traits that may influence offspring competitive ability, dispersal, foraging, and vulnerability to predation and climatic conditions. To quantify the extent to which these maternal traits may ultimately affect an organism's fitness, we undertook laboratory and field experiments with Atlantic salmon (Salmo salar). To control for confounding effects caused by correlated traits, manipulations of the timing of fertilization combined with intraclutch comparisons were used. In the wild, a total of 1462 juveniles were marked at emergence from gravel nests. Recapture rates suggest that up to 83.5% mortality occurred during the first four months after emergence from the gravel nests, with the majority (67.5%) occurring during the initial period ending 17 days after median emergence. Moreover, the mortality was selective during this initial period, resulting in a significant phenotypic shift toward an earlier date of and an increased length at emergence. However, no significant selection differentials were detected thereafter, indicating that the critical episode of selection had occurred at emergence. Furthermore, standardized selection gradients indicated that selection was more intense on date of than on body size at emergence. Timing of emergence had additional consequences in terms of juvenile body size. Late-emerging juveniles were smaller than early-emerging ones at subsequent samplings, both in the wild and in parallel experiments conducted in seminatural stream channels, and this may affect success at subsequent size-selective episodes, such as winter mortality and reproduction. Finally, our findings also suggest that egg size had fitness consequences independent of the effects of emergence time that directly affected body size at emergence and, in turn, survival and size at later life stages. The causality of the maternal effects observed in the present study supports the hypothesis that selection on juvenile traits may play an important role in the evolution of maternal traits in natural populations.     

光合细菌对小麦生长和光合功能的影响

【目的】探明光合细菌对小麦生长、产量及光合功能的影响。【方法】以尧麦16为材料,在不同生长时期施用光合细菌,研究光合细菌对小麦生长、产量及光合功能的影响。【结果】光合细菌培养液的不同成分可提高小麦旗叶SPAD值、光合速率及干物质积累。拔节期施用后,混合菌液对叶片SPAD含量促进作用最大,较不施用对照提高33.6%,小麦干物质积累较对照增加25.7%,单株籽粒重量增效为14.3%。单菌株实验处理中沼泽红假单胞菌促进作用最强,干物质积累和单株籽粒重量较培养基稀释液对照增效均为13.1%。不同施用时期的结果表明沼泽红假单胞菌对灌浆期和拔节期小麦促进效应最强,其中静息细胞可延长叶片功能期,使光合产物持续增加;无细胞培养液通过促进小麦营养生长,进而提高小麦产量。【结论】光合细菌可促进小麦生长,有效提高小麦生育过程中相关光合功能;施用时期应为小麦拔节期和灌浆期;光合细菌对小麦生长和产量促进作用是静息细胞和代谢活性物质综合作用的结果。     

Brassinosteroids as Metahormones: Evidence for their Specific Influence during the Critical Period in Sorghum Development

Abstract: In Sorghum bicolor, the effect of brassinosteroid (BR) treatments on blade elongation depends both on concentration and on the stage of development. A specific period of increase in sensitivity to BR is reported during early vegetative development. It coincides with emergence of a critical period during which the between-organs relationship is readjusted as a function of new developmental events or new environmental conditions. Accordingly, the influence of BR cannot be completely understood without separating its effects during stable phases (phenophases) and during critical periods. A high level of redundancy exists in networks of regulation, so that modifications due to BR treatments generally remain cryptic. Nevertheless, it is shown that BR affects the pattern of relationships between organs, confirming its involvement in emergence of a new network of regulation. It is suggested that, during critical periods, brassinosteroids act as "metahormones" integrating the new emerging regulation network by triggering changes in cellular sensitivity to PGRs.     

Cholesterol acceptor capacity is preserved by different mechanisms in preterm and term fetuses

Fetal serum cholesterol and lipoprotein concentrations differ between preterm and term born neonates. An imbalance of the flow of cholesterol from the sites of synthesis or efflux from cells of peripheral organs to the liver, the reverse cholesterol transport (RCT), is linked to atherosclerosis and cardiovascular disease (CVD). Preterm delivery is a risk factor for the development of CVD. Thus, we hypothesized that RCT is affected by a diminished cholesterol acceptor capacity in preterm as compared to term fetuses. Cholesterol efflux assays were performed in RAW264.7, HepG2, and HUVEC cell lines. In the presence and absence of ABC transporter overexpression by TO-901317, umbilical cord sera of preterm and term born neonates (n = 28 in both groups) were added. Lipid components including high density lipoprotein (HDL), low density lipoprotein (LDL), apolipoprotein A1, and apolipoprotein E were measured and related to fractional cholesterol efflux values. We found overall, fractional cholesterol efflux to remain constant between the study groups, and over gestational ages at delivery, respectively. However, correlation analysis revealed cholesterol efflux values to be predominantly related to HDL concentration at term, while in preterm neonates, cholesterol efflux was mainly associated with LDL. In conclusion cholesterol acceptor capacity during fetal development is kept in a steady state with different mechanisms and lipid fractions involved at distinct stages during the second half of fetal development. However, RCT mechanisms in preterm neonates seem not to be involved in the development of CVD later in life suggesting rather changes in the lipoprotein pattern causative.