Adipokines in pregnancy

Reproductive success consists of a sequential events chronology, starting with the ovum fertilization, implantation of the embryo, placentation, and cellular processes like proliferation, apoptosis, angiogenesis, endocrinology, or metabolic changes, which taken together finally conduct the birth of healthy offspring. Currently, many factors are known that affect the regulation and proper maintenance of pregnancy in humans, domestic animals, or rodents. Among the determinants of reproductive success should be distinguished: the maternal microenvironment, genes, and proteins as well as numerous pregnancy hormones that regulate the most important processes and ensure organism homeostasis. It is well known that white adipose tissue, as the largest endocrine gland in our body, participates in the synthesis and secretion of numerous hormones belonging to the adipokine family, which also may regulate the course of pregnancy. Unfortunately, overweight and obesity lead to the expansion of adipose tissue in the body, and its excess in both women and animals contributes to changes in the synthesis and release of adipokines, which in turn translates into dramatic changes during pregnancy, including those taking place in the organ that is crucial for the proper progress of pregnancy, i.e. the placenta. In this chapter, we are summarizing the current knowledge about levels of adipokines and their role in the placenta, taking into account the physiological and pathological conditions of pregnancy, e.g. gestational diabetes mellitus, preeclampsia, or intrauterine growth restriction in humans, domestic animals, and rodents.

First-trimester irisin and fetuin-A concentration in predicting macrosomia

Objective: We investigated the diagnostic value of first-trimester adipokines and placental markers in predicting macrosomia. Methods: Out of 328 women recruited during the prenatal diagnosis between 11th and 13th week of pregnancy and subjected to follow up until delivery, we selected 26 women who gave birth to macrosomic babies and 34 women who gave birth to normal weight neonates for the evaluation of first trimester serum levels of pregnancy associated plasma protein-A, free β-human chorionic gonadotropin, placental growth factor (PIGF), and selected adipokines. Results: The mothers of macrosomic infants had higher PIGF (p = .049) and irisin concentrations (p = .00003), and lower fetuin-A levels (p = .0002) than had the mothers of normal weight babies. Newborn's weight correlated positively with maternal irisin (R = 0.454, p = .0003) and negatively with fetuin-A concentrations (R = -0.497, p = .00005). Multiple regression analysis showed that only serum irisin concentration was a significant predictor of birth weight (β = 0.329, p = .03), explaining 14% of its variability. The sensitivity and the specificity of irisin concentration in predicting macrosomia were 0.769 and 0.794, respectively (AUC = 0.818 [95%CI: 0.708-0.928], p = .00001) with a proposed cut-off value of 1725.4 ng/ml. Conclusions: Our results suggest that mother's irisin may be an early biomarker of macrosomia.

Maternal adipokines and insulin as biomarkers of pregnancies complicated by overweight and obesity

BACKGROUND

Maternal obesity is associated with several adverse pregnancy outcomes. This study was conducted aiming to evaluate maternal levels of adipokines and insulin in pregnancies complicated by overweight and obesity and its correlations with maternal and fetal outcomes.

METHODS

This cross-sectional study included 72 mother-newborn pairs. Mothers were classified as having normal weight (n = 23), overweight (n = 18), and obesity (n = 31). Maternal adiponectin, leptin, resistin and insulin levels at the end of pregnancy were compared among groups and correlated with maternal and perinatal outcomes. Data were analyzed by ANOVA and correlation tests, with a p value <0.05 being considered as significant.

RESULTS

Obese pregnant women showed higher leptin levels (p = 0.0021). Leptin levels were positively correlated with prepregnancy body mass index-BMI (r = 0.57), gestational (37 or 38 weeks of gestation) BMI (r = 0.39), hypertension (r = 0.27), and hyperglycemia (r = 0.30), and negatively associated with newborns' abdominal circumference (r = -0.25). Adiponectin concentrations were negatively correlated with gestational BMI (r = -0.29) and newborns' cephalic circumference (r = -0.27) and positively correlated with birth weight (r = 0.23). Insulin concentrations correlated positively with prepregnancy BMI (r = 0.38), gestational BMI (r = 0.24) and maternal hyperglycemia (r = 0.26).

CONCLUSIONS

Our findings support the relationship between markers of obesity and maternal-fetal outcomes. Maternal insulin and adipokines levels showed an independent relationship with mother and newborns outcomes, respectively. In this studied population, the results indirectly reinforce the importance of maternal weight control before and during pregnancy to avoid adverse outcomes to mother and their newborns.

Maternal, umbilical arterial and umbilical venous 25-hydroxyvitamin D and adipocytokine concentrations in pregnancies with and without gestational diabetes

OBJECTIVE

Gestational diabetes mellitus (GDM) has been associated with inflammation as well as Vitamin D insufficiency. While Vitamin D has anti-inflammatory properties, relationships between Vitamin D and inflammatory markers remain unexplored in GDM. Therefore, this case--control study investigated adipocytokine and Vitamin D [25(OH)D] concentrations and correlations in GDM and control women, as well as their neonates.

DESIGN/PARTICIPANTS/MEASUREMENTS

seventy-three women participated: 36 GDM and 37 controls. Maternal samples were drawn at 31 weeks. Umbilical arterial and venous samples were collected at birth. 25(OH)D and adipocytokine concentrations were compared for GDM vs control maternal, umbilical arterial and venous samples. Correlations were explored between biochemical results, maternal and neonatal demographics.

RESULTS

Compared with age- and weight-matched control participants, GDM women had significantly lower concentrations of 25(OH)D (77·3 ± 24·3 vs 93·2 ± 19·2 nm/l; P = 0·009); adiponectin (17·5 ± 11·8 vs 34·1 ± 20·3 μg/ml, P < 0·001); resistin (25·4 ± 9·1 vs 31·9 ± 12·1 ng/ml, P = 0·045); and plasminogen activator inhibitor-1 (PAI-1) 13·9 ± 10·0 vs 21·0 ± 12·6 ng/ml, P = 0·038), while delivering 1 week earlier (38·2 ± 1·2 vs 39·5 ± 0·9 weeks, P < 0·001). GDM maternal 25(OH)D concentrations positively correlated with PAI-1, IL-8 and TNF-α concentrations. Umbilical 25(OH)D concentrations were not significantly different in GDM vs control offspring, whereas adiponectin, resistin and PAI-1 concentrations were significantly lower in GDM offspring.

CONCLUSIONS

GDM women had lower 25(OH)D concentrations than controls, while neonatal umbilical concentrations of 25(OH)D did not differ. GDM maternal and GDM offspring had lower adiponectin, resistin and PAI-1 concentrations compared with controls. Results suggest that both GDM women and their offspring demonstrate abnormal adipocytokine patterns.

First trimester maternal BMI is a positive predictor of cord blood c-peptide levels while maternal visfatin levels is a negative predictor of birth weight

OBJECTIVE

The role of first trimester maternal body mass index (BMI) and adipocytokines in cord blood c-peptide and birth weight in pregnancy was investigated.

DESIGN

Seventy non-diabetic pregnant Caucasian women were recruited. Anthropometry and measurements of fasting adipocytokines (visfatin, leptin, adiponectin), insulin and glucose were performed in each of the three trimesters. At birth, birth weight and cord blood c-peptide, glucose, insulin, visfatin, leptin, adiponectin and IL6 in each neonate were measured.

RESULTS

First trimester maternal BMI correlated positively with cord blood c-peptide (p=0.035, r=0.74) and negatively with cord blood visfatin (p=0.049, r=-0.67). First trimester HOMAR was negatively correlated with cord blood visfatin (p=0.037, r=-0.90) and negatively with cord blood leptin (p=0.031, r=0.90). First trimester maternal BMI was a positive predictor of cord blood c-peptide (p=0.007). First trimester maternal visfatin levels were negative predictors of birth weight (p=0.017).

CONCLUSIONS

We conclude that first trimester maternal BMI and serum visfatin seem to be strongly associated with fetal insulin secretion and final birth weight, respectively, suggesting a role of early-pregnancy maternal adipose tissue in the pregnancy metabolic environment.

Adipocytokines levels at delivery, functional variation of TFAP2β, and maternal and neonatal anthropometric parameters

OBJECTIVE

Adipocytokines participate in the regulation of glucose metabolism and fetal development. The transcription factor activating protein 2B (TFAP2β) has been associated with adipocytokine regulation, and gene variations with type 2 diabetes and obesity. This study investigated associations between maternal TFAP2B variation, adipocytokine levels, and maternal and neonatal anthropometric characteristics.

DESIGN AND METHODS

A population-based sample of women was followed from delivery to 6 months postpartum. Adiponectin, leptin, and interleukin-6 levels at delivery, and maternal as well as neonatal anthropometric variables were assessed. The TFAP2β intron 1 variable number tandem repeat (VNTR) was genotyped.

RESULTS

Maternal interleukin-6 correlated positively with leptin at delivery, with peripartum weight changes and weight of newborn males, adjusted for potential confounders. Leptin at delivery was associated with TFAP2β intron 1 VNTR genotype, adjusted for confounders, maternal weight and negatively with birth weight among female neonates. A path model suggested a link between TFAP2β genotype, leptin levels, and newborn females' weight.

CONCLUSIONS

The present results stress a role for the TFAP2 β in adiposity-related conditions and intrauterine growth. The association between neonatal birth weight and maternal adipocytokine levels, together with the observed sex effect, call for further studies on the mechanisms behind neuroendocrine fetal programming.

Association of Adiponectin Gene Polymorphism With Birth Weight in Korean Neonates

Adiponectin has been associated with insulin resistance and type 2 diabetes mellitus and possibly fetal growth. Our aim was to assess the association between the single nucleotide polymorphisms (SNPs) of the adiponectin gene (ADIPOQ) and the birth sizes. We investigated four SNPs of ADIPOQ (rs182052, rs2241766, rs1501299, and rs266729) and birth height and weight in 237 healthy full-term neonates. The neonates with the rs182052 G allele had a greater birth weight (p = .043 in the dominant model) and a higher ponderal index (p = .028 in the additive model). The rs2241766 G allele was associated with a greater birth weight (p = .016 in the recessive model). In a logistic regression analysis, the homozygotes for the rs182052 G allele and those for the rs2241766 G allele showed a significant association with a greater birth weight above 90 percentile (OR 2.75, 95% CI 1.13–6.70 and OR 5.15, 95% CI 1.66–15.99, respectively). In conclusion, we found an association between rs182052 and rs2241766 and birth weight and ponderal index among healthy neonates and suggested that adiponectin might have some roles in fetal growth.

Maternal and cord blood adiponectin multimeric forms in gestational diabetes mellitus: a prospective analysis

OBJECTIVE

To analyze the relationship between maternal adiponectin (mAdiponectin) and cord blood adiponectin (cbAdiponectin) multimeric forms (high molecular weight [HMW], medium molecular weight [MMW], and low molecular weight [LMW]) in a cohort of gestational diabetes mellitus (GDM) and normal glucose-tolerant (NGT) pregnant women.

RESEARCH DESIGN AND METHODS

A total of 212 women with a singleton pregnancy, 132 with NGT and 80 with GDM, and their offspring were studied. Maternal blood was obtained in the early third trimester and cord blood was obtained at delivery. Total adiponectin and the multimeric forms of adiponectin were determined in cord blood and maternal serum. Spearman rank correlation and stepwise linear correlation analysis were used to assess the relationship between cbAdiponectin levels and clinical and analytical parameters.

RESULTS

No differences in cbAdiponectin concentration or its multimeric forms were observed in the offspring of diabetic mothers compared with NGT mothers. The HMW-to-total adiponectin ratio was higher in cord blood than in maternal serum, whereas the MMW- and LMW-to-total adiponectin ratio was lower. Cord blood total and HMW adiponectin levels were positively correlated with birth weight and the ponderal index (PI), whereas cord blood MMW adiponectin was negatively correlated with the PI. In addition, cbAdiponectin and its multimeric forms were correlated with mAdiponectin concentrations. In the multivariate analysis, maternal multimeric forms of adiponectin emerged as independent predictors of cbAdiponectin, its multimers, and their distribution.

CONCLUSIONS

cbAdiponectin concentrations are independently related to mAdiponectin levels and unrelated to the diagnosis of GDM. Maternal multimeric forms of adiponectin are independent predictors of the concentrations of cbAdiponectin and its multimeric forms at delivery.

Plasma levels of resistin-like molecule beta in humans

BACKGROUND

Resistin-like molecules (RELM) are expressed in many tissues and among those, RELMβ is most abundantly expressed in the colon. Based on animal studies, RELMβ is induced by high fat diets, obesity, and intestinal microflora and may play a role in insulin resistance and intestinal inflammation. In the present study, we evaluated whether RELMβ could be measured in human plasma and the influence of selected host and behavioral factors on RELMβ levels, including known risk factors for colorectal cancer.

METHODS

The subjects for this pilot study were derived from healthy controls who participated in a population-based case-control study of colorectal cancer in Metropolitan Detroit. The subjects were 45-80 years of age without history of cancer or colorectal resection.

RESULTS

RELMβ was present in human plasma, with levels in the range of 0.08-0.26 ng/mL. Lower RELMβ levels were found in subjects with non-Caucasian race, lower pack-years of smoking, and higher physical activity index scores. Other variables such as dietary intakes, gender, obesity, use of non-steroidal anti-inflammatory agents and history of polyps were not associated with RELMβ levels.

CONCLUSIONS

The direct association of RELMβ with smoking and inverse association with physical activity, both of which are risk factors for colon cancer, indicates that RELMβ may be involved in mediating the effects of these two lifestyle factors on risk of colon cancer.