Circulating levels of growth hormone, insulin-like growth factor-I and prolactin in normal, growth retarded and anencephalic human fetuses

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.

Prolactin from Pluripotency to Central Nervous System Development

Prolactin (PRL) is a versatile hormone that exerts more than 300 functions in vertebrates, mainly associated with physiological effects in adult animals. Although the process that regulates early development is poorly understood, evidence suggests a role of PRL in the early embryonic development regarding pluripotency and nervous system development. Thus, PRL could be a crucial regulator in oocyte preimplantation and maturation as well as during diapause, a reversible state of blastocyst development arrest that shares metabolic, transcriptomic, and proteomic similarities with pluripotent stem cells in the naïve state. Thus, we analyzed the role of the hormone during those processes, which involve the regulation of its receptor and several signaling cascades (Jak/Mapk, Jak/Stat, and PI3k/Akt), resulting in either a plethora of physiological actions or their dysregulation, a factor in developmental disorders. Finally, we propose models to improve the knowledge on PRL function during early development.

Serum level of ghrelin in umbilical cord in small and appropriate for gestational age newborn infants and its relationship to anthropometric measures

OBJECTIVE

To compare the cord blood ghrelin level in (SGA) infants with the level in appropriate for gestational age (AGA) infants, and determine its relationship to anthropometric measurements at delivery.

MATERIALS AND METHODS

Fifty newborn infants (30 SGA newborns and 20 AGA infants) were included in the study and were subjected to complete clinical examinations, anthropometric measurement, and ghrelin assays.

RESULTS

The cord blood ghrelin level in SGA infants was significantly higher than that in AGA infants. Cord ghrelin level correlated negatively with gestational age, weight, length, and body mass index in SGA group.

CONCLUSION

Cord ghrelin concentration increased in SGA infants due to state of prolonged undernutrition the source of ghrelin unknown may be from the mother placenta or fetal tissues.

Periconceptional maternal folic acid use of 400 microg per day is related to increased methylation of the IGF2 gene in the very young child

BACKGROUND

Countries worldwide recommend women planning pregnancy to use daily 400 microg of synthetic folic acid in the periconceptional period to prevent birth defects in children. The underlying mechanisms of this preventive effect are not clear, however, epigenetic modulation of growth processes by folic acid is hypothesized. Here, we investigated whether periconceptional maternal folic acid use and markers of global DNA methylation potential (S-adenosylmethionine and S-adenosylhomocysteine blood levels) in mothers and children affect methylation of the insulin-like growth factor 2 gene differentially methylation region (IGF2 DMR) in the child. Moreover, we tested whether the methylation of the IGF2 DMR was independently associated with birth weight.

METHODOLOGY/PRINCIPAL FINDINGS

IGF2 DMR methylation in 120 children aged 17 months (SD 0.3) of whom 86 mothers had used and 34 had not used folic acid periconceptionally were studied. Methylation was measured of 5 CpG dinucleotides covering the DMR using a mass spectrometry-based method. Children of mother who used folic acid had a 4.5% higher methylation of the IGF2 DMR than children who were not exposed to folic acid (49.5% vs. 47.4%; p = 0.014). IGF2 DMR methylation of the children also was associated with the S-adenosylmethionine blood level of the mother but not of the child (+1.7% methylation per SD S-adenosylmethionine; p = 0.037). Finally, we observed an inverse independent association between IGF2 DMR methylation and birth weight (-1.7% methylation per SD birthweight; p = 0.034).

CONCLUSIONS

Periconceptional folic acid use is associated with epigenetic changes in IGF2 in the child that may affect intrauterine programming of growth and development with consequences for health and disease throughout life. These results indicate plasticity of IGF2 methylation by periconceptional folic acid use.

Abnormal vessel morphology in boys born after intracytoplasmic sperm injection

AIM

Children born after intracytoplasmic sperm injection (ICSI) are at risk of preterm birth, low birth weight and perinatal morbidity which may predispose for diseases of the central nervous and vascular systems. Our aim was to investigate the ocular fundus morphology in children born after ICSI.

METHOD

Children born after ICSI (n = 82) had ocular fundus photographs taken at the age of 5 years and results were compared with those of a control group (n = 203). The ocular fundus morphology with the central retinal vessels was evaluated by digital image analysis.

RESULTS

Children born after ICSI (n = 57) had abnormal retinal vascularization as evidenced by a lower number of vascular branching points compared with the control group (n = 181) (p = 0.0002). A gender difference was found whereby the ICSI boys (n = 35) had significantly fewer retinal branching points (median 24, range 19-29.5) compared with the control boys (median 27.5, range 20-37) (p < 0.0001).

CONCLUSION

Our findings showed that ICSI boys have abnormal vessel morphology as demonstrated by a reduced number of central retinal branching points. The difference still remained after elimination of factors earlier shown to be associated with a low number of vascular branching points, i.e. low birth weight and preterm, suggesting other mechanisms responsible for the low number of vascular branching points.

The fetal response to chronic placental insufficiency

Fetal growth restriction is most commonly caused by failure of the placenta to meet the increasing demands for oxygen and substrate of the developing fetus, resulting in common fetal compensatory responses. Understanding these responses is helpful in developing a management strategy that will optimize pregnancy outcome.

Fetal growth restriction and postnatal development

The interaction between genetic constitution and in utero environment determines fetal growth and development and influences the susceptibility to certain disorders in adulthood. Data from both animal and human studies indicate that prenatal and early postnatal malnutrition can program the hypothalamus-pituitary-adrenal axis (HPA axis), altering neuroendocrine response to stressors throughout lifetime. Impaired uteroplacental perfusion results in fetal growth restriction (FGR). In FGR there is evidence of chronic hypoxemia and alterations in metabolic, endocrine, and hematological parameters, compatible with starvation. Furthermore, FGR is associated with increased perinatal mortality and in the survivors there is increased susceptibility to diabetes and cardiovascular disease in adulthood. There is evidence that early postnatal growth acceleration, which would normally be considered desirable, may exacerbate metabolic dysfunction in later life.

Aspects of placental growth hormone physiology

Placental growth hormone (PGH) has been known for 20 years. Nevertheless, its physiology is far from understood. In this review, basal aspects of PGH physiology are summarised and put in relation to the highly homologous pituitary growth hormone (GH). During normal pregnancy, PGH progressively replaces GH and reach maximum serum concentrations in the third trimester. A close relationship to insulin-like growth factor (IGF)-I and -II levels is observed. Furthermore, PGH levels are positively associated to fetal growth. The potential importance of growth hormone receptors and binding protein for PGH effects is discussed. Finally, the review outlines current knowledge of PGH in pathological pregnancies.

Neural tube defects and associated anomalies in a fetal and perinatal autopsy series

Neural tube defects (NTDs) are congenital malformations of the central nervous system (CNS) secondary to abnormal closure of the neural tube during embryonic development. This study provides information on NTD rate, distribution, associated morphologic anomalies and organ weights in a Danish fetal and perinatal autopsy series during a 16 year period. The data were extracted from the autopsy reports of a consecutive series of 1984 fetal and perinatal autopsies from the Copenhagen area performed in the period 1989-2004. Registered parameters included: The location and morphology of the NTD, associated morphological anomalies, and organ weights. Organ weights were evaluated according to new fetal autopsy standards and grouped as low, normal or high. Ninety-seven NTD cases were found (4.9%): Spina bifida (38 cases), cephalocele (17 cases) and anencephaly (42 cases). 63% of NTD cases had associated morphologic anomalies. Among the most common were hydrocephalus, NTD in another region, and anomalies in the urogenital system. 58% of the NTD cases had abnormal weight of one or more organs. Most notable was low adrenal weight not only in anencephalic fetuses but also in cases with cephalocele, suggesting a possible association.

IGF-1 and Retinopathy of Prematurity in the Preterm Infant

BACKGROUND

Retinopathy of prematurity (ROP) continues to be a major cause of blindness in children. Although ablation of the retina reduces the incidence of blindness by suppressing the neovascular phase of ROP, the visual outcomes after treatment are often poor. Preventive therapy is required and will likely come from a better understanding of the pathophysiology of the disease.

OBJECTIVES

To study the role of insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) in both the proliferative phase of ROP (phase II) and in the early phase when blood vessels are lost.

METHODS

Using both a mouse model of ROP and clinical studies the relationship between IGF-1, VEGF and both vessel loss and vessels proliferation in the retina was studied.

RESULTS

IGF-1 is required for maximum VEGF activation of vascular endothelial cell proliferation and survival pathways. IGF-1 levels are deficient after premature birth, setting the stage for retinal vascular loss and ROP.

CONCLUSIONS

Restoration of IGF-1 to levels found in utero may help prevent ROP.

The role of maternal factors, postnatal nutrition, weight gain, and gender in regulation of serum IGF-I among preterm infants

IGF-I is important for somatic growth and development of the human fetus and neonate. IGF-I also plays an important role in normal vascularization of human retina, as it has been suggested that insufficient IGF-I may be a factor in the development of retinopathy of prematurity. The principal regulator of the bioavailability of IGF-I in the circulation is IGF binding protein 3 (IGFBP-3). The aim of this study was to study factors associated with postnatal serum concentrations of IGF-I and of IGFBP-3 in preterm infants from birth to an age corresponding to 40 wk postmenstruation. We conducted a prospective, longitudinal study in which we measured serum IGF-I and IGFBP-3 concentrations in 76 preterm infants from birth (postmenstrual ages 23-32 wk) until discharge from hospital around 40 wk. Information regarding nutrition, weight gain, maternal factors, and treatment with corticosteroids were collected weekly. Variables found to be associated with postnatal change over time of serum IGF-I and IGFBP-3 were postmenstrual age (p<0.001), weight gain (standard deviation score) (p<0.001), and enteral intake of protein (p<0.001). Male gender was associated with lower IGF-I levels (p<0.001). The relationship between protein intake and IGF-I (and also between protein intake and IGFBP-3) was positive, as was the relationship between weight gain and IGF-I (and between weight gain and IGFBP-3). These results indicate that the degree of prematurity, low enteral protein intake, male gender, and slow weight gain are associated with a slower postnatal increase of IGF-I in preterm infants.

Prenatal diagnosis of absence of the septum pellucidum associated with septo-optic dysplasia

Septo-optic dysplasia (SOD; De Morsier syndrome) is a rare congenital disorder characterized by the absence of the septum pellucidum (SP), hypoplasia of the optic chiasma and nerves, and various types of hypothalamic-pituitary dysfunction. We report on two fetuses with absence of the SP diagnosed by ultrasound examination at 29 and 30 gestational weeks. In the first case the diagnosis of SOD was suspected in utero and confirmed postnatally; to the best of our knowledge this is the first report of the prenatal diagnosis of SOD. In the second case absence of the SP appeared to be isolated and no visual or endocrine impairment were detected after birth.

Circulating levels of inhibin A, inhibin B and activin A in normal and intrauterine growth restricted (IUGR) fetuses

OBJECTIVE

To evaluate the relationships between circulating levels of inhibin A, inhibin B and activin A, and sex, gestational age and gonadotropins in normal and pathological fetuses.

STUDY DESIGN

The study included 31 normal fetuses and 12 affected with intrauterine growth restriction (IUGR) of gestational age ranging 20-40 weeks.

RESULTS

No gender difference in inhibin A and activin A levels were observed. Inhibin B levels were significantly higher in males than in females (P < 0.05). Fetuses with the highest levels of inhibin A and B were found in the IUGR group that also showed activin A levels significantly higher than normal. No correlations were observed between inhibin A, inhibin B, activin A and both gonadotropins.

CONCLUSION

Plasma inhibin A, inhibin B and activin A are detectable in both genders during intrauterine life. The different gender pattern of inhibin B suggests that inhibin B may contribute to the assessment of the hypothalamic-pituitary-gonadal set-point at least in males.

Immunocytochemical study of the GH cells in the anterior pituitary gland of human fetus II. Anencephalic fetus

In order to elucidate the effects of hypothalamic regulation on the morphology of GH cells, light and electron microscopic immunocytochemical examinations were carried out comparing GH cells in the anterior pituitary gland of anencephalic fetus with those of normal fetuses. Three types of GH cells were identified in the anterior pituitary gland of anencephalic fetus as well as in the normal fetus. Type-I is a small, round cell containing a few small secretory granules. Type-III is a large, polygonal cell with numerous large secretory granules. Type-II is a polygonal cell with medium-sized secretory granules. The Type-II GH cell was predominant in both anencephalic and normal fetuses. The most striking difference between anencephalic and normal fetuses was the presence of atypical forms of the Type II cell. These were polygonal cells containing secretory granules, which were either immunopositive or immunonegative to anti-human GH (anti-hGH) serum. Furthermore, two other types of GH cells were identified. The somatomammotroph (SM cell) contained GH and PRL in different granules within the same cell. Also, a different type of the GH cell was noted containing two varieties of secretory granules; one was immunolabeled only with anti-hGH and the other was not immunolabeled to either anti-hGH or anti-human PRL (anti-hPRL). From these results, we suggest that an absence of hypothalamic regulation in the anencehpalic does not seriously modify GH cell morphology but induces an altered GH storage pattern in some of the cells.

Abnormal retinal vascular morphology in young adults following intrauterine growth restriction

OBJECTIVE

Intrauterine growth restriction (IUGR) resulting in low birth weight for gestational age may predispose one to development of cardiovascular disease later in life. Abnormal fetal blood flow in the presence of fetal growth restriction helps to distinguish infants with true fetal growth impairment from small but normal infants. Our goal was to investigate associations between IUGR with abnormal fetal blood flow and abnormal retinal vascular morphology at 18 years of age.

METHODS

A prospective study was performed with 21 subjects with IUGR (abnormal fetal aortic blood flow velocity; birth weight small for gestational age; median birth weight deviation from the population mean of -31% [range: -22% to -42%] and in 23 subjects with birth weight appropriate for gestational age [normal fetal aortic blood flow velocity; median birth weight deviation of -2% (range: -10% to 22%)]). The retinal vessel morphology was evaluated by digital image analysis.

RESULT

Subjects with IUGR (n = 21) had significantly less retinal vascularization as evidenced by a lower number of vascular branching points (median: 26; range: 20-31) as compared with the subjects who were born appropriate for gestational age (median: 28; range: 26-32). Within the entire group (N = 44), increasing negative birth weight deviation was associated with a reduced number of vascular branching points (r = 0.36.

CONCLUSION

Our findings show that IUGR with abnormal fetal blood flow is associated with abnormal retinal vascular morphology in young adult life.

Serum concentrations of iodine, thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH) and insulin-like growth factor 1 (IGF-1) during the last trimester of pregnancy, during labour, and in early puerperium of women with normal pregnancy or with in

In women with intrauterine growth retardation (IUGR), insulin-like growth factor 1 (IGF-1) concentrations tended to reduce during the last trimester of pregnancy. Parameters of thyroid function in maternal serum were not distinctly influenced by IUGR, except for high concentrations of iodine. Triiodothyronine (T3) concentrations in cord blood of normal pregnancies was significantly lower than maternal concentrations, but was relatively high when the fetus was growth retarded. The results are discussed in connection with changes of thyroid function and changes of IGF-1 during pregnancy.

Uteroplacental insufficiency lowers the threshold towards hypoxia-induced cerebral apoptosis in growth-retarded fetal rats

Infants suffering uteroplacental insufficiency and hypoxic ischemic injury often demonstrate cerebral apoptosis. Our objective was to determine the global effects of uteroplacental insufficiency upon cerebral gene expression of the apoptosis related proteins Bcl-2 and Bax and their role in increasing vulnerability to hypoxia-induced cerebral apoptosis. We therefore caused uteroplacental insufficiency and growth retardation by performing bilateral uterine artery ligation upon pregnant rats 2 days prior to term delivery and elicited further perinatal fetal hypoxia by placing maternal rats in 14% FiO(2) 3 h prior to delivery. We quantified cerebral levels of Bcl-2 and Bax mRNA, lipid peroxidation, caspase-3 activity, and cAMP in control and growth retarded term rat pups that experienced either normoxia or hypoxia. Uteroplacental insufficiency alone caused a significant decrease in cerebral Bcl-2 mRNA levels without altering cerebral Bax mRNA levels, malondialdehyde levels, or caspase-3 activity. In contrast, uteroplacental insufficiency and subsequent fetal hypoxia significantly increased cerebral Bax mRNA levels, lipid peroxidation and caspase-3 activity; Bcl-2 mRNA levels continued to be decreased. Hypoxia alone increased cerebral cAMP levels, whereas uteroplacental insufficiency and subsequent hypoxia decreased cerebral cAMP levels. We speculate that the decrease in Bcl-2 gene expression increases the vulnerability towards cerebral apoptosis in fetal rats exposed initially to uteroplacental insufficiency and subsequent hypoxic stress.

Anomalous costochondral cartilage in fetal anencephaly

Anencephaly is a human fetal malformation with absence of brain and calvarium superior to the orbits. The consequent absence of hypothalamus provides a unique model for studying human development, and therefore skeletal growth, in the absence of hypothalamic hormones and their regulatory functions. To assess the influence of hypothalamic insufficiency on cartilage development, we studied costochondral cartilage sections from eight anencephalic fetuses (18-22 weeks old) and seven controls (16-22 weeks old) with pathologies not directly related to skeletal growth. We found a previously undescribed anomalous organization of the cartilage in the anencephalic. The proliferative chondrocytes showed a disordered appearance with an increased proliferative zonal length (156 +/- 28 microm in anencephalic fetuses vs. 103 +/- 14 microm in controls, p = 0.006) and a concomitant decrease in the maturing portion, where cells form ordered isogenic groups (58 +/- 13 microm in anencephalic fetuses vs. 93 +/- 19 microm in controls, p = 0.003). In addition, cell density was significantly decreased in the proliferating and maturing zones in the anencephalic cases (84 +/- 21 vs. 130 +/- 21 cells/40 microm(2) in proliferating zone; 53 +/- 8 vs. 94 +/- 8 in maturing portion, p < 0.005). These alterations in the developing cartilage of the anencephalic may contribute to the observed growth retardation in these fetuses and reflect modifications in pituitary hormones and growth factors resulting from reduction in hypothalamopituitary function.

Regulation of fetal amino acid metabolism: substrate or hormonal regulation?

Insulin is regarded as the primary fetal growth-promoting hormone, but direct in vivo experimental data supporting this conjecture are sparse. Data obtained from studies in in vivo, chronically catheterized fetal lambs under a variety of experimental circumstances demonstrate that glucose availability is the primary modulator of fetal protein accretion, via its ability to diminish amino acid catabolism. The ovine fetus is shown to be resistant to insulin-induced suppression of proteolysis, relative to the adult. Data from studies in the human premature infant show that the findings in the ovine fetus are similar to those in the ex utero premature human.