Success of Programming Fetal Growth Phenotypes Among Obese Women

Telomere length and fetal programming: A review of recent scientific advances

We sought to synthesize a comprehensive literature review comprising recent research linking fetal programming to fetal telomere length. We also explored the potential effects fetal telomere length shortening has on fetal phenotypes. Utilizing the PubMed database as our primary search engine, we retrieved and reviewed 165 articles of published research. The inclusion criteria limited the articles to those that appeared within the last ten years, were pertinent to humans, and without restriction to language of publication. Our results showed that socio-demographic factors like age, sex, genetic inheritance, and acquired disease impact telomere length. Further, we found several maternal characteristics to be associated with fetal telomere length shortening, and these include maternal chemical exposure (eg, tobacco smoke), maternal stress during pregnancy, maternal nutritional and sleeping disorders during pregnancy as well as maternal disease status. Due to paucity of data, our review could not synthesize evidence directly linking fetal phenotypes to telomere length shortening. Although the research summarized in this review shows some association between determinants of intrauterine programming and fetal telomere length, there is still significant work that needs to be done to delineate the direct relationship of telomere attrition with specific fetal phenotypes.

Maternal obesity and occurrence of fetal macrosomia: a systematic review and meta-analysis

OBJECTIVE

To determine a precise estimate for the contribution of maternal obesity to macrosomia.

DATA SOURCES

The search strategy included database searches in 2011 of PubMed, Medline (In-Process & Other Non-Indexed Citations and Ovid Medline, 1950-2011), and EMBASE Classic + EMBASE. Appropriate search terms were used for each database. Reference lists of retrieved articles and review articles were cross-referenced.

METHODS OF STUDY SELECTION

All studies that examined the relationship between maternal obesity (BMI ≥30 kg/m(2)) (pregravid or at 1st prenatal visit) and fetal macrosomia (birth weight ≥4000 g, ≥4500 g, or ≥90th percentile) were considered for inclusion.

TABULATION, INTEGRATION, AND RESULTS

Data regarding the outcomes of interest and study quality were independently extracted by two reviewers. Results from the meta-analysis showed that maternal obesity is associated with fetal overgrowth, defined as birth weight ≥ 4000 g (OR 2.17, 95% CI 1.92, 2.45), birth weight ≥4500 g (OR 2.77,95% CI 2.22, 3.45), and birth weight ≥90% ile for gestational age (OR 2.42, 95% CI 2.16, 2.72).

CONCLUSION

Maternal obesity appears to play a significant role in the development of fetal overgrowth. There is a critical need for effective personal and public health initiatives designed to decrease prepregnancy weight and optimize gestational weight gain.

Markers of endothelial cell dysfunction are increased in human omental adipose tissue from women with pre-existing maternal obesity and gestational diabetes

OBJECTIVE

To determine the effect of maternal obesity and gestational diabetes mellitus (GDM) on the expression and release of genes involved in endothelial cell dysfunction in human placenta and omental adipose tissue.

MATERIALS/METHODS

Human placenta and omental adipose tissue were obtained from non-obese and obese normal glucose tolerant (NGT) women and women with GDM at the time of Caesarean section. Quantitative RT-PCR was performed to determine the level of expression. Tissue explants were performed to determine the release of proteins of interest.

RESULTS

There was no effect of pre-existing maternal obesity or GDM on placental gene expression or secretion of members of the VEGF family members (PLGF and VEGF-A expression and secretion; sFlt-1 release; VEGFR1 and VEGFR2 mRNA expression); FGFR1 mRNA expression, FGF2 mRNA expression and secretion; endoglin mRNA expression and secretion (sEng); and the adhesion molecules ICAM-1 and VCAM-1. On the other hand, in omental adipose tissue, pre-existing maternal obesity and GDM were associated with increased gene expression of PLGF, endoglin and ICAM-1 and increased secretion of PLGF, sFlt-1, FGF2, sEng and sICAM-1. There was, however, no effect of maternal pre-existing obesity and GDM on VEGF-A, VEGFR1, VEGFR2, FGFR1 and VCAM-1 expression or secretion.

CONCLUSIONS

This study demonstrated the presence of abnormal expression and secretion of angiogenic proteins and adhesion molecules in omental adipose tissue, but not placenta, from pregnant women with GDM and pre-existing maternal obesity. Increased angiogenic and adhesion molecules released from adipose tissue may affect angiogenesis, inflammation and or lipid and glucose metabolism in both mum and her offspring.

Lower cerebrospinal fluid/plasma fibroblast growth factor 21 (FGF21) ratios and placental FGF21 production in gestational diabetes

Objectives

Circulating Fibroblast Growth Factor 21 (FGF21) levels are increased in insulin resistant states such as obesity, type 2 diabetes mellitus and gestational diabetes mellitus (GDM). In addition, GDM is associated with serious maternal and fetal complications. We sought to study human cerebrospinal fluid (CSF) and corresponding circulating FGF21 levels in women with gestational diabetes mellitus (GDM) and in age and BMI matched control subjects. We also assessed FGF21 secretion from GDM and control human placental explants.

Design

CSF and corresponding plasma FGF21 levels of 24 women were measured by ELISA [12 GDM (age: 26–47 years, BMI: 24.3–36.3 kg/m²) and 12 controls (age: 22–40 years, BMI: 30.1–37.0 kg/m²)]. FGF21 levels in conditioned media were secretion from GDM and control human placental explants were also measured by ELISA.

Results

Glucose, HOMA-IR and circulating NEFA levels were significantly higher in women with GDM compared to control subjects. Plasma FGF21 levels were significantly higher in women with GDM compared to control subjects [234.3 (150.2–352.7) vs. 115.5 (60.5–188.7) pg/ml; P<0.05]. However, there was no significant difference in CSF FGF21 levels in women with GDM compared to control subjects. Interestingly, CSF/Plasma FGF21 ratio was significantly lower in women with GDM compared to control subjects [0.4 (0.3–0.6) vs. 0.8 (0.5–1.6); P<0.05]. FGF21 secretion into conditioned media was significantly lower in human placental explants from women with GDM compared to control subjects (P<0.05).

Conclusions

The central actions of FGF21 in GDM subjects maybe pivotal in the pathogenesis of insulin resistance in GDM subjects. The significance of FGF21 produced by the placenta remains uncharted and maybe crucial in our understanding of the patho-physiology of GDM and its associated maternal and fetal complications. Future research should seek to elucidate these points.

Omentin-1 is decreased in maternal plasma, placenta and adipose tissue of women with pre-existing obesity

OBJECTIVE

The aim of this study was to determine (i) the effect of maternal obesity and gestational diabetes mellitus (GDM) on (i) the circulating levels of omentin-1 in cord and maternal plasma, and (ii) gene expression and release of omentin-1 from human placenta and adipose tissue. The effect of pregnancy on circulating omentin-1 levels was also determined.

DESIGN

Omentin-1 levels were measured in maternal and cord plasma from obese and non-obese normal glucose tolerant women (NGT; n = 44) and women with GDM (n = 39) at the time of term elective Caesarean section. Placenta and adipose tissue expression and release of omentin-1 was measured from 22 NGT and 22 GDM women collected at the time of term elective Caesarean section. Omentin-1 levels were also measured in maternal plasma from 13 NGT women at 11 and 28 weeks gestation and 7 weeks postpartum.

RESULTS

Maternal obesity was associated with significantly lower omentin-1 levels in maternal plasma; however, there was no effect of maternal obesity on cord omentin levels. Omentin-1 gene expression was lower in placenta and adipose tissue obtained from women with pre-existing obesity. In addition to this, adipose tissue release of omentin-1 was significantly lower from obese pregnant women. Omentin-1 levels were significantly lower in non-obese GDM compared to non-obese NGT women. However, there was no difference in omentin-1 levels between obese NGT and obese GDM women. There was no effect of GDM on cord omentin levels, and placental and adipose tissue omentin-1 expression. Maternal omentin-1 levels were negatively correlated with fetal birthweight and fetal ponderal index.

CONCLUSIONS

The data presented in this study demonstrate that pre-existing maternal obesity is associated with lower omentin-1 expression in placenta, adipose tissue and maternal plasma. Alteration in omentin-1 in pregnancy may influence the development of metabolic disorders in offspring later in life.

Need for early interventions in the prevention of pediatric overweight: a review and upcoming directions

Childhood obesity is currently one of the most prevailing and challenging public health issues among industrialized countries and of international priority. The global prevalence of obesity poses such a serious concern that the World Health Organization (WHO) has described it as a "global epidemic." Recent literature suggests that the genesis of the problem occurs in the first years of life as feeding patterns, dietary habits, and parental feeding practices are established. Obesity prevention evidence points to specific dietary factors, such as the promotion of breastfeeding and appropriate introduction of nutritious complementary foods, but also calls for attention to parental feeding practices, awareness of appropriate responses to infant hunger and satiety cues, physical activity/inactivity behaviors, infant sleep duration, and family meals. Interventions that begin at birth, targeting multiple factors related to healthy growth, have not been adequately studied. Due to the overwhelming importance and global significance of excess weight within pediatric populations, this narrative review was undertaken to summarize factors associated with overweight and obesity among infants and toddlers, with focus on potentially modifiable risk factors beginning at birth, and to address the need for early intervention prevention.

Adverse fetal and neonatal outcomes associated with a life-long high fat diet: role of altered development of the placental vasculature

Maternal obesity results in a number of obstetrical and fetal complications with both immediate and long-term consequences. The increased prevalence of obesity has resulted in increasing numbers of women of reproductive age in this high-risk group. Since many of these obese women have been subjected to hypercaloric diets from early childhood we have developed a rodent model of life-long maternal obesity to more clearly understand the mechanisms that contribute to adverse pregnancy outcomes in obese women. Female Sprague Dawley rats were fed a control diet (CON--16% of calories from fat) or high fat diet (HF--45% of calories from fat) from 3 to 19 weeks of age. Prior to pregnancy HF-fed dams exhibited significant increases in body fat, serum leptin and triglycerides. A subset of dams was sacrificed at gestational day 15 to evaluate fetal and placental development. The remaining animals were allowed to deliver normally. HF-fed dams exhibited a more than 3-fold increase in fetal death and decreased neonatal survival. These outcomes were associated with altered vascular development in the placenta, as well as increased hypoxia in the labyrinth. We propose that the altered placental vasculature may result in reduced oxygenation of the fetal tissues contributing to premature demise and poor neonatal survival.

Fetal serum folate concentrations and placental folate transport in obese women

OBJECTIVE

We hypothesized that fetal folate serum concentrations are lower and placental folate transport is impaired in pregnancies of obese women.

STUDY DESIGN

Umbilical vein serum and placental tissue were collected from normal weight and obese pregnant women at term. Cellular localization (immunohistochemistry) of folate receptor-α (FR-α), proton coupled folate transporter (PCFT), and reduced folate carrier (RFC) was established. Protein expression (Western blot) and transporter activity (isotope labeled methyltetrahydrofolate) were determined in syncytiotrophoblast microvillus membranes (MVM).

RESULTS

Fetal folate concentrations were similar in obese women as compared with normal weight women. Protein expression of FR-α in microvillus membranes was increased (+173%), in RFC was decreased (-41%), and in PCFT was unchanged. However, activity of FR-α, PCFT, and RFC was unaltered in obesity.

CONCLUSION

Fetal serum folate concentrations and placental folate transport activity are not altered in obesity at term, which suggests that limited availability of folate does not contribute to abnormal gene methylation and developmental programming.

Aberrant fetal growth and early, late, and postneonatal mortality: an analysis of Milwaukee births, 1996-2007

OBJECTIVE

The objective of the study was to ascertain the association between fetal growth (small- [SGA], appropriate- [AGA], and large-for-gestational-age [LGA]) and early, late, and postneonatal mortality.

STUDY DESIGN

Birth certificate data for nonanomalous singletons, delivered from 1996 to 2007, were obtained for Milwaukee residents. Multivariate logistic regression analyses, adjusted for 19 covariates, determined the association between fetal growth and mortality.

RESULTS

Among the 123,383 live births, SGA was 57% higher than LGA (11% vs 7%). The infant mortality rate for SGA was 11.0, AGA, 5.3, and LGA, 2.7/1000 live births. SGA was a significant risk factor for early (adjusted odds ratio, 2.66) and late (2.06) but not postneonatal mortality. The adjusted risk of mortality for LGA was not significantly different from AGA. Over 12 years, 3 types of mortality for aberrant fetal growth did not change significantly.

CONCLUSION

In the city of Milwaukee, aberrant fetal growth was variably associated with early, late, and postneonatal mortality.

Experimentally induced gestational androgen excess disrupts glucoregulation in rhesus monkey dams and their female offspring

Discrete fetal androgen excess during early gestation in rhesus monkeys (Macaca mulatta) promotes endocrine antecedents of adult polycystic ovary syndrome (PCOS)-like traits in female offspring. Because developmental changes promoting such PCOS-like metabolic dysfunction remain unclear, the present study examined time-mated, gravid rhesus monkeys with female fetuses, of which nine gravid females received 15 mg of testosterone propionate (TP) subcutaneously daily from 40 to 80 days (first to second trimesters) of gestation [term, mean (range): 165 (155-175) days], whereas an additional six such females received oil vehicle injections over the same time interval. During gestation, ultrasonography quantified fetal growth measures and was used as an adjunct for fetal blood collections. At term, all fetuses were delivered by cesarean section for postnatal studies. Blood samples were collected from dams and infants for glucose, insulin, and total free fatty acid (FFA) determinations. TP injections transiently accelerated maternal weight gain in dams, very modestly increased head diameter of prenatally androgenized (PA) fetuses, and modestly increased weight gain in infancy compared with concurrent controls. Mild to moderate glucose intolerance, with increased area-under-the-curve circulating insulin values, occurred in TP-injected dams during an intravenous glucose tolerance test in the early second trimester. Moreover, reduced circulating FFA levels occurred in PA fetuses during a third trimester intravenous glucagon-tolbutamide challenge (140 days gestation), whereas excessive insulin sensitivity and increased insulin secretion relative to insulin sensitivity occurred in PA infants during an intravenous glucose-tolbutamide test at ∼1.5 mo postnatal age. Data from these studies suggest that experimentally induced fetal androgen excess may result in transient hyperglycemic episodes in the intrauterine environment that are sufficient to induce relative increases in pancreatic function in PA infants, suggesting in this nonhuman primate model that differential programming of insulin action and secretion may precede adult metabolic dysfunction.

The impact of previous cesarean section on the success of future fetal programming pattern

PURPOSE

The purpose of this study is to examine whether cesarean section in the first pregnancy is associated with the success or failure of programmed fetal growth phenotypes or patterns in the subsequent pregnancy.

METHODS

We analyzed data from a population-based retrospective cohort of singleton deliveries that occurred in the state of Missouri from 1978 to 2005 (n = 1,224,133). The main outcome was neonatal mortality, which was used as an index of the success of fetal programming. Cox proportional hazard and logistic regression models were used to generate point estimates and 95% confidence intervals.

RESULTS

Mothers delivering by cesarean section in the first pregnancy were less likely to deliver subsequent appropriate-for-gestational-age (AGA) neonates (OR 0.91, 95% CI 0.89-0.92) when compared with mothers delivering vaginally. Of the 1,457 neonatal deaths in the second pregnancy, 383 early neonatal and 95 late neonatal deaths were to mothers with cesarean section deliveries in the first pregnancy. When compared with women with a previous vaginal delivery, AGA neonates of women with a primary cesarean section had 20% increased risk of both neonatal (OR 1.20, 95% CI 1.05-1.37) and early neonatal (OR 1.23, 95% CI 1.05-1.43) death.

CONCLUSION

Our study suggests that previous cesarean section is a risk factor for neonatal mortality among AGA infants of subsequent pregnancy. Future prospective studies are needed to confirm these findings.

Early growth patterns and long-term obesity risk

PURPOSE OF REVIEW

This review is an update on recent findings regarding early growth patterns and later obesity. These data are important because the potential programming of obesity in early life provides hope for new prevention strategies targeting early growth for long-term benefits.

RECENT FINDINGS

Recent findings regarding the association of childhood or adulthood obesity with fetal growth, gestational weight gain, maternal diabetes, or infancy weight gain are reviewed. Some related outcomes and potential mechanisms are also described. Most studies remain observational and confirm previous findings, but some intervention studies have begun to appear in the recent literature and support some, but not other, observed associations.

SUMMARY

Past and recent findings confirm the association of early growth patterns with obesity. However, causality must be demonstrated and safety must be established before translating these findings into public health recommendations.