Adipokine, adropin and endothelin-1 levels in intrauterine growth restricted neonates and their mothers

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.

The Mother-Child Dyad Adipokine Pattern: A Review of Current Knowledge

An important role in the network of interconnections between the mother and child is played by adipokines, which are adipose tissue hormones engaged in the regulation of metabolism. Alternations of maternal adipokines translate to the worsening of maternal insulin resistance as well as metabolic stress, altered placenta functions, and fetal development, which finally contribute to long-term metabolic unfavorable conditions. This paper is the first to summarize the current state of knowledge concerning the concentrations of individual adipokines in different biological fluids of maternal and cord plasma, newborn/infant plasma, milk, and the placenta, where it highlights the impact of adverse perinatal risk factors, including gestational diabetes mellitus, preeclampsia, intrauterine growth restriction, preterm delivery, and maternal obesity on the adipokine patterns in maternal-infant dyads. The importance of adipokine measurement and relationships in biological fluids during pregnancy and lactation is crucial for public health in the area of prevention of most diet-related metabolic diseases. The review highlights the huge knowledge gap in the field of hormones participating in the energy homeostasis and metabolic pathways during perinatal and postnatal periods in the mother-child dyad. An in-depth characterization is needed to confirm if the adverse outcomes of early developmental programming might be modulated via maternal lifestyle intervention.

Biomarkers of cardiovascular disease risk in the neonatal population

The consistently high prevalence of cardiovascular disease (CVD) has urged the need for punctual and effective prevention. Extended research on this specific area has demonstrated the influence of fetal and neonatal periods on the risk of developing CVD in adulthood. Thus, the role of traditional and novel biological markers to the effective screening of CVD among the neonatal population is widely investigated. The objective of the present narrative review is to examine those neonatal biomarkers that may play a role in the development of CVD, to exhibit scientific data that appertain to their association with various perinatal conditions leading to CVD predisposition, and their potential role on prediction and prevention strategies. Multiple biomarkers, traditional and novel, have been mined across the studied literature. Adiposity, insulin resistance, altered lipid profile, inflammation, and endothelial dysfunction seem among the headliners of CVD. Even though various novel molecules have been studied, their clinical utility remains controversial. Therefore, it is quite important for the scientific community to find elements with strong predictive value and practical clinical use.

Maternal Serum and Cord Blood Leptin Concentrations at Delivery in Normal Pregnancies and in Pregnancies Complicated by Intrauterine Growth Restriction

INTRODUCTION

Leptin is a polypeptide hormone, and in pregnancy, it is secreted by the placenta and maternal and fetal adipose tissues. Normal leptin production is a factor responsible for uncomplicated gestation, embryo development, and fetal growth. The study compared maternal serum and cord blood leptin concentrations at delivery in normal pregnancies and in pregnancies complicated by intrauterine growth restriction (IUGR).

METHODS

The study was performed in 25 pregnant women with isolated IUGR and in 194 pregnant women without any complications. Leptin concentrations in maternal serum and in cord blood samples collected at delivery were measured by ELISA and subsequently analyzed by maternal body mass index (BMI), mode of delivery, and infant gender and birth weight. For comparative analyses of normally distributed variables, parametric tests were used, that is, the Student t test and a one-way ANOVA. The nonparametric Mann-Whitney test was used when the distribution was not normal. The Pearson correlation coefficient was calculated to assess the correlation between normally distributed variables (p < 0.05).

RESULTS

In pregnancies complicated by IUGR, the mean maternal serum leptin concentration at delivery was significantly higher (52.73 ± 30.49 ng/mL) than in normal pregnancies (37.17 ± 28.07 ng/mL) (p = 0.01). The mean cord blood leptin concentration in pregnancies complicated by IUGR was 7.97 ± 4.46 ng/mL and significantly lower than in normal pregnancies (14.78 ± 15.97 ng/mL) (p = 0.04). In normal pregnancies, but not in pregnancies complicated by IUGR, a statistically significant correlation was established between maternal serum leptin concentrations and maternal BMI at delivery (r = 0.22; p = 0.00). No statistically significant correlation was found between cord blood leptin concentrations and maternal BMI in either study subjects or controls. In normal pregnancies, but not in pregnancies complicated by IUGR, a strong correlation was observed between cord blood leptin concentrations and birth weight (r = 0.23; p = 0.00).

CONCLUSIONS

Elevated maternal blood leptin concentrations in pregnancies complicated by IUGR may indicate a significant adverse effect of elevated leptin on fetal growth. The differences in leptin concentrations, measured in maternal serum and in cord blood, between the study subjects and controls suggest that deregulated leptin levels may increase the risk of obstetric complications associated with placental insufficiency.

Genetic Background of Fetal Growth Restriction

Fetal growth restriction (FGR) is one of the most formidable challenges in present-day antenatal care. Pathological fetal growth is a well-known factor of not only in utero demise in the third trimester, but also postnatal morbidity and unfavorable developmental outcomes, including long-term sequalae such as metabolic diseases, diabetic mellitus or hypertension. In this review, the authors present the current state of knowledge about the genetic disturbances responsible for FGR diagnosis, divided into fetal, placental and maternal causes (including preeclampsia), as well as their impact on prenatal diagnostics, with particular attention on chromosomal microarray (CMA) and noninvasive prenatal testing technique (NIPT).

Maternal and fetal serum leptin levels and their association with maternal and fetal variables and labor: A cross-sectional study

Background

Leptin is a polypeptide hormone that may be implicated in the pathogenesis of various disorders during pregnancy. We sought to determine serum leptin levels among pregnant women and their fetuses and to investigate their association with fetal and maternal variables.

Method

452 pregnant women who attended to labor ward between January 2020 and August 2020 were included in the study. Serum leptin concentrations were measured using enzyme-linked immunosorbent assay method. Mann-Whitney U test and Spearman's correlation test were used for statistical analysis. A multivariate linear regression analysis was then performed. Significance level was considered at alpha <0.05.

Results

The median maternal and fetal serum leptin levels were 6.42 [4.16-8.51] ng/mL and 2.9 [1.03-5.36] ng/mL respectively. There was no significant correlation between maternal and fetal serum leptin levels (p = 0.064). Maternal serum leptin levels correlated positively with maternal body mass index (BMI) (r = 0.117, p = 0.005). Besides, maternal serum leptin levels were significantly higher in nulliparous women (7.57 [4.45-9.30] ng/mL vs. 6.22 [4.02-8.30] ng/mL, p = 0.037) and in women who were in active labor (6.83 [4.39-8.92] ng/mL vs. 6.25 [4.04-8.30] ng/mL, p = 0.047). Fetal serum leptin levels were significantly higher in large for gestational age (LGA) fetuses (4.81 [2.13-7.22] ng/mL vs. 2.80 [0.96-5.16] ng/mL, p = 0.003) and in fetuses with preterm premature ruptures of membranes (PPROM) (5.23 [2.42-8.07] ng/mL vs. 2.86 [1.00-5.23] ng/mL, p = 0.021).

Conclusion

Maternal serum leptin levels were influenced by maternal BMI, parity and labor. Fetal serum leptin levels were higher among LGA fetuses and in fetuses with PPROM.

Maternal blood leptin concentration in small for gestational age: a meta-analysis

Monitoring leptin concentration in maternal blood would be useful for earlier identification of mothers at risk of delivering small for gestational age (SGA) neonates. This study was performed to examine whether maternal blood leptin concentrations are different between SGA neonates and healthy controls. Meta-analysis was performed to summarize the data of all English-language studies providing the numbers of SGA neonates, the numbers of healthy controls, and the means and standard deviations of maternal blood leptin concentrations in these two groups. The studies were collected by searching ten databases including PubMed (MEDLINE) and investigating the PubMed Related Citations and bibliographic references. The Newcastle-Ottawa Scale was used to assess study quality. Publication bias was assessed using Egger's test. The primary outcome of this study was the standardized mean difference (SMD) in maternal blood leptin concentration between SGA neonates and healthy controls. Thirty-two overall good-quality studies involving 1734 women and their neonates were extracted from 17 articles. Synthetic evidence did not indicate statistically significant SMD in maternal blood leptin concentration between SGA neonates and healthy controls (P = 0.172). Egger's test showed no publication bias (P = 0.309).Conclusion: Maternal blood leptin concentration is not significantly different between SGA neonates and healthy controls. What is Known: • Monitoring leptin concentration in maternal blood would be useful for earlier identification of mothers at risk of delivering small for gestational age (SGA) neonates. What is New: • The results of this meta-analysis including 1734 women and their neonates in 32 overall good-quality studies showed that maternal blood leptin concentration is not significantly different between SGA neonates and healthy controls.

Adropin and Inflammation Biomarker Levels in Male Patients With Obstructive Sleep Apnea: A Link With Glucose Metabolism and Sleep Parameters

STUDY OBJECTIVES

The main objectives of the study were to determine plasma adropin, systemic inflammation biomarker levels, and glucose metabolism parameters in patients with moderate and severe obstructive sleep apnea (OSA) compared to healthy controls.

METHODS

In this study, we included 50 male patients with OSA (25 moderate and 25 severe) and 25 age- and sex-matched control subjects. All subjects underwent fasting sampling of peripheral blood for laboratory analyses.

RESULTS

Adropin plasma levels were significantly lower in the severe OSA group in comparison with the moderate and control groups (4.50 ± 1.45 versus 6.55 ± 1.68 versus 8.15 ± 1.79 ng/mL, P < .001). Plasma biomarkers of systemic inflammation were significantly increased in patients with moderate OSA (interleukin [IL]-6 and tumor necrosis factor alpha [TNF-α]) and severe OSA (IL-6, TNF-α, high-sensitivity C-reactive protein) when compared with controls (P < .001). Adropin levels showed a significant negative correlation with IL-6 (r = -.419, P < .001), TNF-α (r = -.540, P < .001), fasting glucose (r = -.331, P = .004), hemoglobin A1c (r = -.438, P < .001), homeostatic model assessment insulin resistance index (r = -.213, P = .046), and polysomnographic parameters including apnea-hypopnea index (r = -.615, P < .001) and oxygen desaturation index (r = -.573, P < .001). A multivariate regression analysis showed that plasma adropin remained as a significant negative predictor of severe OSA status, when adjusted for age and body mass index and computed along with other inflammatory biomarkers in the regression model (odds ratio 0.069, 95% confidence interval 0.009-0.517, P = .009).

CONCLUSIONS

Plasma adropin concentrations significantly correlate with indices of disease severity in patients with OSA, suggesting that adropin potentially plays an important role in the complex pathophysiology of the disease.

Disparity in fetal growth between twin and singleton gestation: the role of adipokines

OBJECTIVE

Twin pregnancies are characterized by unique pattern of attenuated fetal weight gain during late gestation compared with singleton gestation. The mechanism(s) responsible for regulating twin growth has not yet elucidated. Leptin and adiponectin are two adipocytokines implicated in metabolism and energy balance of fetuses, newborns and adults. Moreover, these hormones have been suggested to play a role in fetal growth. The objective of the study was to determine cord blood adiponectin and leptin in twins and singletons, with and without growth impairment.

STUDY DESIGN

This was a case-control study. It included two groups of newborns, matched for gestational age and birth weight percentile: singleton (n=60 newborns) and twins (n=44 newborns). Adiponectin and leptin were determined in cord blood, and compared between the groups according to clinical and demographic characteristics. Non-parametric and parametric statistical methods were employed.

RESULTS

Median adiponectin and leptin concentrations were lower in twins vs singletons (P<0.001 for both comparisons). Among small for gestational age newborns (SGA), median concentration of adiponectin (P=0.04), but not leptin (P=0.1), was lower in twins compared to singletons. In pooled analysis (singleton plus twins), cord blood adiponectin and leptin were strongly correlated with gestational age (P<0.001 and P=0.005, respectively) and birth weight (P<0.001 and P<0.001, respectively). Regression analysis revealed that plurality (P=0.02) was significantly and independently associated with cord blood adiponectin concentrations, after adjustment for confounding variables. Similar regression in which leptin was the independent variable revealed that only birth weight (P=0.01) was significantly and independently associated with cord blood leptin concentrations.

CONCLUSIONS

Twin pregnancies are associated with lower cord blood concentrations of adiponectin and leptin compared with singleton gestations. However, only cord blood adiponectin, but not leptin, was lower in SGA neonates. Collectively, these data suggest that adiponectin may be implicated in the mechanism accounting for the growth disparity between twins and singletons.

Maternal and Cord Blood Adiponectin Concentrations in Small for Gestational Age: A Meta-Analysis

Background: Adiponectin, which may have a growth-promoting effect through its insulin-sensitizing action, is thought to play a key role in fetal growth. This study was performed to determine whether maternal and/or cord blood adiponectin concentrations differ between small for gestational age (SGA) and healthy controls. Methods: Databases were searched to identify good quality English language studies providing the number of SGA and healthy controls, and the means and standard deviations of maternal or cord blood adiponectin concentration in both groups. A meta-analysis was performed to summarize the standardized mean differences (SMDs) in maternal and cord blood adiponectin concentrations between SGA and healthy controls. Results: There was no statistically significant difference in maternal blood adiponectin concentration between SGA and healthy controls (n = 8, p = 0.951). However, cord blood adiponectin concentration was significantly lower in SGA than in healthy controls (n = 6, p = 0.028), and the effect was large (i.e., SMD >0.7). Conclusions: Maternal blood adiponectin concentration is not low in SGA compared with healthy controls. However, SGA shows lower cord blood adiponectin concentration than healthy controls.

Leptin action in normal and pathological pregnancies

Leptin is now considered an important signalling molecule of the reproductive system, as it regulates the production of gonadotrophins, the blastocyst formation and implantation, the normal placentation, as well as the foeto‐placental communication. Leptin is a peptide hormone secreted mainly by adipose tissue, and the placenta is the second leptin‐producing tissue in humans. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes such as proliferation, protein synthesis, invasion and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including polycystic ovary syndrome, recurrent miscarriage, gestational diabetes mellitus, pre‐eclampsia and intrauterine growth restriction. Due to the relevant incidence of the mentioned diseases and the importance of leptin, we decided to review the latest information available about leptin action in normal and pathological pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy.

Modeling the impact of growth and leptin deficits on the neuronal regulation of blood pressure

The risk of hypertension is increased by intrauterine growth restriction (IUGR) and preterm birth. In the search for modifiable etiologies for this life-threatening cardiovascular morbidity, a number of pathways have been investigated, including excessive glucocorticoid exposure, nutritional deficiency and aberration in sex hormone levels. As a neurotrophic hormone that is intimately involved in the cardiovascular regulation and whose levels are influenced by glucocorticoids, nutritional status and sex hormones, leptin has emerged as a putative etiologic and thus a therapeutic agent. As a product of maternal and late fetal adipocytes and the placenta, circulating leptin typically surges late in gestation and declines after delivery until the infant consumes sufficient leptin-containing breast milk or accrues sufficient leptin-secreting adipose tissue to reestablish the circulating levels. The leptin deficiency seen in IUGR infants is a multifactorial manifestation of placental insufficiency, exaggerated glucocorticoid exposure and fetal adipose deficit. The preterm infant suffers from the same cascade of events, including separation from the placenta, antenatal steroid exposure and persistently underdeveloped adipose depots. Preterm infants remain leptin deficient beyond term gestation, rendering them susceptible to neurodevelopmental impairment and subsequent cardiovascular dysregulation. This pathologic pathway is efficiently modeled by placing neonatal mice into atypically large litters, thereby recapitulating the perinatal growth restriction-adult hypertension phenotype. In this model, neonatal leptin supplementation restores the physiologic leptin surge, attenuates the leptin-triggered sympathetic activation in adulthood and prevents leptin- or stress-evoked hypertension. Further pathway interrogation and clinical translation are needed to fully test the therapeutic potential of perinatal leptin supplementation.

Association between serum adropin level and burden of coronary artery disease in patients with non-ST elevation myocardial infarction

Objective:

Previous studies revealed the relationship between stable coronary artery disease (CAD) and serum adropin level, but this relationship has not been investigated in patients with non-ST segment elevation myocardial infarction (NSTEMI). The present study is an analysis of the relationship between adropin and severity of CAD assessed based on SYNTAX score in patients with NSTEMI.

Methods:

A total of 109 participants, 80 patients with NSTEMI and 29 healthy individuals, were prospectively enrolled in the study. Patients with NSTEMI were divided to 2 groups: high SYNTAX score (≥32) (35 patients) and low SYNTAX score (<32) (45 patients). Adropin level was measured from blood serum samples using enzyme-linked immunosorbent assay test.

Results:

Patients with NSTEMI and high SYNTAX score had significantly lower serum adropin level (2357.30 pg/mL±821.58) compared to NSTEMI patients with low SYNTAX score (3077.00 pg/mL±912.86) and control group (3688.00±956.65). Adropin cut-off value for predicting high SYNTAX score on receiver-operating characteristic curve analysis was determined to be 2759 pg/mL, with a sensitivity of 63% and a specificity of 57%. Adropin was an independent predictor for high SYNTAX score (odds ratio=0.999; 95% confidence interval: 0.998–1.000; p=0.007).

Conclusion:

Adropin could be an alternative blood sample value for predicting severity of CAD.