Abundance of adiponectin in the newborn

The Influence of Maternal Obesity and Breastfeeding on Infant Appetite- and Growth-Related Hormone Concentrations: The SKOT Cohort Studies

BACKGROUND/AIMS

Exposure to obesity during pregnancy may lead to adverse changes in the offspring's metabolic profile. We compared appetite- and growth-related hormones in a cohort of infants born to obese mothers (SKOT-II) with infants born mainly to nonobese mothers (SKOT-I).

METHODS

Infants from SKOT-I (n = 273) and SKOT-II (n = 132) were examined including anthropometric measurements and blood samples analyzed for glucose, insulin, insulin-like growth factor-I (IGF-I), adiponectin, and leptin. Information on breastfeeding and parental characteristics were also collected.

RESULTS

At 9 months of age, SKOT-II infants were 3.6% heavier and 1.2% longer than SKOT-I infants even though their mothers were shorter. There was no difference in body mass index (BMI). SKOT-II infants had higher levels of insulin, adiponectin, and leptin but lower levels of IGF-I compared to SKOT-I infants (all p ≤ 0.015). These differences remained, except for leptin, when adjusted for current weight. Breastfeeding versus nonbreastfeeding at 9 months was associated with lower concentrations of all hormones (all p ≤ 0.003). In adjusted models, maternal BMI at 9 months was positively associated with insulin and adiponectin and negatively with IGF-I.

CONCLUSIONS

Pre-pregnancy obesity confers symmetrically larger infant body size and higher levels of most growth- and appetite-related hormones but surprisingly lower levels of IGF-I, suggesting other possible infant growth-promoting effects through insulin.

Associations of maternal and cord blood adipokines with offspring adiposity in Project Viva: is there an interaction with child age?

OBJECTIVES

Higher leptin and lower adiponectin correlate with adult and childhood adiposity, but it is unclear how exposure to these adipokines during gestation relates to offspring growth. We aimed to investigate the relationships of maternal and cord adipokines with offspring adiposity across childhood to early adolescence, as well as interactions with child age.

METHODS

In mother-child pairs in the Project Viva cohort, we measured adipokines in mothers at second trimester (n=1106) and in cord blood at birth (n=657). We measured offspring adiposity indices at early childhood (mean 3.3±s.d. 0.3 years), mid-childhood (7.9±0.8 years) and early adolescence (13.2±0.9 years). We analyzed associations of maternal and cord adipokines with offspring longitudinal adiposity using a linear mixed model adjusting for pre-pregnancy body mass index (BMI), gestational weight gain (GWG), and other confounders.

RESULTS

Mothers with higher BMI and GWG had higher leptin. Offspring born to mothers with the highest vs lowest quartile of leptin had lower BMI z-score (-0.49 units, 95% confidence interval (CI):-0.72,-0.26), waist circumference (-2.6 cm, 95% CI: -3.7,-1.5) and sum of subscapular and triceps skinfolds (-2.8 mm, 95% CI: -4.1,-1.4) in early life. An interaction term between maternal leptin and child age was positive, suggesting that the associations between maternal leptin and child adiposity were not constant over time. Offspring born to mothers with lowest vs highest quartile of maternal adiponectin had lower early life adiposity (BMI z-score -0.27 units, 95% CI: -0.48,-0.05). Results were similar for cord leptin but not cord adiponectin.

CONCLUSIONS

Our findings showed higher maternal and cord leptin, and lower maternal adiponectin are associated with lower offspring adiposity from childhood to early adolescence, independent of maternal BMI and GWG. However, the strength of these associations was not constant over time.

Adiponectin and leptin in human severe insulin resistance - diagnostic utility and biological insights

There is an intimate interplay between systemic insulin action and the actions of the adipocyte-derived proteins leptin and adiponectin. Concordant findings in humans and rodents demonstrate that leptin gates critical physiological functions to the prevailing nutritional state, however the physiological functions of adiponectin are less convincingly established. Murine evidence suggests that adiponectin can exert insulin-sensitising effects, plasma concentrations of adiponectin in humans correlate in most populations with insulin sensitivity, and increasingly strong evidence suggests an association between common genetic variation around the adiponectin gene and diabetes. However rare and severe genetic variants lowering adiponectin levels have not been convincingly associated with insulin resistance, and the discordant and sometimes extreme hyperadiponectinaemia seen in patients with severe insulin resistance due to loss of insulin receptor function poses a challenge to the widely held view that low adiponectin in humans plays a role in causing prevalent insulin resistance. The mechanism underlying this phenomenon remains to be elucidated, but the best available evidence implicates increased production of adiponectin in states of insulin receptor dysfunction, attributable at least in part to increased transcription of the ADIPOQ gene. Further investigation of the cellular basis of insulin receptoropathy-related hyperadiponectinaemia may shine further light on the human pathobiology of this most abundant and enigmatic product of adipose tissue.

[In utero fetal programming and its impact on health in adulthood]

Adverse events during intrauterine life may program organ growth and favor disease later in life. This is the usually called 'Barker's hypothesis'. Increasing evidence suggests that conditions like vascular disease, hypertension, metabolic syndrome, and type 2 diabetes mellitus are programmed during the early stages of fetal development and become manifest in late stages of life, when there is an added impact of lifestyle and other conventional acquired environmental risk factors that interact with genetic factors. The aim of this review was to provide additional, updated evidence to support the association between intrauterine fetal health and increased prevalence of chronic non-communicable diseases in adulthood. Various potential cellular and molecular mechanisms proposed to be related to the above hypothesis are discussed, including endothelial function, oxidative stress, insulin resistance, and mitochondrial function.

Cord blood adiponectin and infant growth at one year

OBJECTIVE

The aim of this study was to determine the association between cord blood adiponectin and leptin and early infant growth at one year in small for gestational age (SGA) and appropriate for gestational age (AGA) infants.

STUDY DESIGN

In this prospective study adiponectin and leptin concentrations were determined in cord blood of (i) AGA newborns (n = 44) and (ii) SGA newborns (n = 24). At one year of age, height and weight were measured. Linear regression analysis was used to determine which factors were associated with anthropometric measurements at the age of one year.

RESULTS

(i) SGA neonates had a significantly lower median cord blood adiponectin and leptin than AGA neonates; (ii) among SGA neonates, cord blood adiponectin concentrations were negatively correlated with body weight at one year, weight gain after one year and with BMI at one year; and (iii) among AGA neonates cord blood adiponectin concentrations were negatively correlated with body weight at one year, weight gain after one year and with BMI at one year.

CONCLUSION

The disparity in cord blood adiponectin and leptin concentrations between SGA and AGA neonates suggests a role for adipokines in fetal growth.

Preeclampsia and adiponectin in cord blood

AIMS

To compare cord blood concentrations of total adiponectin in the offspring of pregnancies with and without preeclampsia.

METHODS

Using a Luminex analyzer, cord blood adiponectin was measured in 182 singleton pregnancies with preeclampsia and compared to adiponectin measured in 511 singleton pregnancies without preeclampsia.

RESULTS

Adiponectin levels in cord blood increased with increasing gestational age, but overall, crude levels were similar in pregnancies with and without preeclampsia. However, in pregnancies with early delivery (weeks 32-36), and in pregnancies with delivery after spontaneous contractions, adiponectin levels were higher in the preeclampsia group.

CONCLUSION

In preterm pregnancies and in pregnancies with spontaneous contractions, adiponectin levels in cord blood were higher in the preeclampsia group than in pregnancies without preeclampsia, maybe reflecting the need to optimize energy in preeclampsia.

Hypoadiponectinemia--cause or consequence of human "insulin resistance"?

CONTEXT

Adiponectin is a highly abundant plasma protein synthesized nearly exclusively in adipose tissue from the ADIPOQ gene. It has excited intense interest because of robust correlation of its circulating levels with indices of insulin resistance (IR) and risk of type 2 diabetes, and their unusual inverse relationship with fat mass. It has been suggested that pharmacological strategies aimed at augmenting adiponectin levels or action may generate novel insulin-sensitizing drugs.

EVIDENCE ACQUISITION

Relevant publications were identified by searching PubMed, with secondary searches of their bibliographies.

EVIDENCE SYNTHESIS

Rodent studies suggest that adiponectin exerts a direct insulin-sensitizing effect on the liver, consistent with a role in the pathogenesis of prevalent forms of IR and its sequelae. However, the complex higher-order structure of adiponectin and inconsistent reports regarding its putative receptors have complicated efforts to understand the mechanistic basis of this. No proof yet exists that adiponectin modulates insulin sensitivity in humans, and genetic, biochemical, and physiological evidence suggests that low adiponectin levels may be a consequence of IR with compensatory hyperinsulinemia. This suggests that there may be a bidirectional relationship between IR and hypoadiponectinemia in humans.

CONCLUSIONS

The relationship between adiponectin and insulin action in humans is more complex than often suggested. Further investigation of the direction of causality in this relationship, allied to studies of the cellular mechanisms involved, will be central to improving understanding of the physiological role of this enigmatic protein, and to efforts to exploit it for therapeutic benefit.

Metabolic syndrome in children and adolescents--risk for sleep-disordered breathing and obstructive sleep-apnoea syndrome?

The clinical relevance of the term "metabolic syndrome", the definition criteria, and predictive power are being disputed. Inclusion of sleep-disordered breathing and sleep apnoea into a definition of metabolic syndrome is also controversial once children and/or adolescents are affected. Nevertheless, along with the increasing prevalence of childhood obesity, the prevalence of the metabolic syndrome in obese children is reported at 30%, irrespective of the definition applied. Moreover, childhood obesity is associated with sleep-disordered breathing. Adipocytokines, cytokines secreted from adipose tissue, are thought to play a major role in the pathophysiology of metabolic syndrome. Leptin was initially suggested as a promising "anti-obesity" hormone. New concepts indicate that in humans leptin and its soluble receptor may be more important in states of energy deficiency rather than a predictor of the metabolic syndrome. Adiponectin, on the other hand, is not only related to obesity and insulin resistance, but appears to be the strongest predictor for metabolic syndrome, even in children. In newborns and infants, both adipocytokines occur in high concentrations, even though this cannot completely explain the increased risk for ensuing metabolic disease later in life. Finally, low-grade systemic inflammation may underlie the clustering of metabolic risk factors. Overall factors from the adipose tissue may constitute not only markers but also mediators of metabolic sequelae of obesity.

Epidermal growth factor and parathyroid hormone-related peptide mRNA in the mammary gland and their concentrations in milk: effects of postpartum hypoxia in lactating rats

The physiological adaptations of the neonatal rat to hypoxia from birth include changes in gastrointestinal function and intermediary metabolism. We hypothesized that the hypoxic lactating dam would exhibit alterations in mammary gland function leading to changes in the concentration of milk peptides that are important in neonatal gastrointestinal development. The present study assessed the effects of chronic hypoxia on peptides produced by the mammary glands and present in milk. Chronic hypoxia decreased the concentration of epidermal growth factor (EGF) in expressed milk and pup stomach contents and decreased maternal mammary gland EGF mRNA. The concentration of parathyroid hormone-related protein (PTHrp) was unchanged in milk and decreased in pup stomach contents; however, mammary PTHLH mRNA was increased by hypoxia. There was a significant increase in adiponectin concentrations in milk from hypoxic dams. Chronic hypoxia decreased maternal body weight, and pair feeding normoxic dams an amount of food equivalent to hypoxic dam food intake decreased body weight to an equivalent degree. Decreased food intake did not affect the expression of EGF, PTHLH, or LEP mRNA in mammary tissue. The results indicated that chronic hypoxia modulated mammary function independently of hypoxia-induced decreases in maternal food intake. Decreased EGF and increased adiponectin concentrations in milk from hypoxic dams likely affect the development of neonatal intestinal function.

Obesity: the hormonal milieu

PURPOSE OF REVIEW

Obesity has reached epidemic proportions throughout the world and poses significant health and economic burdens to both developed and developing societies. Most recent data from the NHANES study (2003-2004) report that 17.1% of US children are overweight and 32.2% of adults are obese, a significant increase compared with data obtained only 6 years earlier.

RECENT FINDINGS

The neurohormonal control of appetite, body composition, and glucose homeostasis is mediated by hormones secreted from adipose tissue, endocrine glands, and enteroendocrine cells, which converge at the vagus nerve, brainstem and hypothalamus to modulate complex interactions of neurotransmitters and central appetite-regulating peptides. These hormonal signals are tightly regulated to maintain body weight/adiposity within a narrow, individually defined range that may be further impacted by variables such as ingested calories, meal composition, and lifestyle.

SUMMARY

Clinical manifestations of obesity, the metabolic syndrome and impaired glucose tolerance reflect biochemical alterations in a complex hormonal milieu. Elucidation of these hormonal perturbations in obese patients has already provided novel pharmacologic treatments to improve weight management and address the metabolic sequelae of obesity. The remarkable redundancy of these hormones, however, and their interactions make a monopharmaceutical approach unlikely to be successful.

Integration of physiological and molecular mechanisms of the developmental origins of adult disease: new concepts and insights

It is now well established that an imbalance or reduction in the maternal diet either through pregnancy and lactation or at defined time points therein can have long-term effects on cardiovascular and metabolic health in the resulting offspring; the exact outcome varying greatly with the period of development or growth targeted. The EARly Nutrition programming – long-term follow up of Efficacy and Safety Trials and integrated epidemiological, genetic, animal, consumer and economic research (EARNEST), or metabolic programming, project aims to determine the primary physiological and molecular mechanisms that cause long-term changes in both cardiovascular function and metabolic homeostasis. Thereafter, it also aims to examine nutritional interventions that could be adopted in order to overcome such complications. The present review summarises some of the more recent findings from a range of nutritional interventions in both small and large animals that are beginning to uncover novel pathways by which long-term health can be determined. These interventions include nutritional manipulations that can increase or decrease blood pressure in the resulting offspring as well as indicating their dissociation from adaptations in the kidney. Particular emphasis will be placed on growth during lactation in conjunction with the extent to which central and peripheral tissue adaptations can act to amplify, or protect, the offspring from later disease when born to nutritionally-manipulated mothers.

Circulating levels of adiponectin in preterm infants

OBJECTIVE

To determine circulating levels of adiponectin in preterm infants and examine possible associations with anthropometric measurements, weight gain, and leptin and insulin levels.

DESIGN

Prospective study.

SETTING

A university hospital neonatal care unit.

STUDY POPULATION

62 preterm (mean (SD) gestational age 32.0 (2.1) weeks) and 15 full-term infants (reference group).

INTERVENTIONS

Blood samples taken at discharge (40.9 (14.8) days of life) from the preterm infants and at a comparable postnatal age in full-term infants. All infants were fed the same commercial formula, but in nine preterms the formula contained long-chain polyunsaturated fatty acids (LCPUFAs).

MAIN OUTCOME MEASURES

Serum levels of adiponectin, leptin and insulin. Associations of adiponectin levels were tested only in the preterm group.

RESULTS

Serum levels of adiponectin were lower in preterm (40.9 (14.8) microg/ml) than full-term infants (53.1 (16.0) microg/ml, p<0.01). However, after adjustment for body weight, the influence of prematurity on adiponectin levels was no longer significant. In preterm infants, adiponectin levels independently correlated with being born small for gestational age (SGA) (beta=-0.35, p=0.01), weight gain (beta=0.28, p=0.03) and LCPUFA-supplemented formula (beta=0.34, p=0.009). Serum adiponectin levels did not correlate with insulin or leptin levels. However, insulin levels were higher in preterm than in full-term infants after adjustment for body weight.

CONCLUSIONS

Adiponectin levels are lower in preterm infants at discharge than full-term infants probably due to decreased adiposity. The levels are influenced by being born SGA, weight gain and, possibly, by dietary LCPUFAs. The importance of these findings in the development of insulin or leptin resistance in children born prematurely needs to be further studied.

New predictors of the metabolic syndrome in children--role of adipocytokines

There is ample discussion of the relevance of the metabolic syndrome, the definition criteria, and predictive power. Nevertheless, along with the increasing prevalence of childhood obesity, the prevalence of the metabolic syndrome in obese children is reported at 30%, irrespective of the definition applied. Because children are otherwise relatively free of co-morbidities, they constitute an interesting population in which to study the sequence of events of obesity-related pathology. The adipocytokines appear to be important in this respect. Leptin was initially suggested as a promising "antiobesity" hormone. New concepts indicate that, in humans, leptin and its soluble receptor may be more important in states of energy deficiency rather than a predictor of the metabolic syndrome. Adiponectin, on the other hand, is not only related to obesity and insulin resistance, but appears to be the strongest predictor for metabolic syndrome, even in children. In newborns and infants, both adipocytokines occur in high concentrations, even though this cannot completely explain the increased risk for ensuing metabolic disease later in life. Finally, low-grade systemic inflammation may underlie the clustering of metabolic risk factors, but their role in children remains to be specified. Overall factors from the adipose tissue may constitute not only markers but also mediators of metabolic sequelae of obesity.

Adiponectin, Adipocyte Fatty Acid Binding Protein, and Epidermal Fatty Acid Binding Protein: Proteins Newly Identified in Human Breast Milk

Background: Breastfeeding may protect children from developing metabolic syndrome and other diseases later in life. We investigated novel proteins in human breast milk that might play a role in this process.

Methods: We used ELISA to measure adiponectin, adipocyte and epidermal fatty acid binding proteins (AFABP, EFABP), and leptin concentrations in human breast milk obtained from 59 mothers 48 h after initiation of lactation. Using a questionnaire and medical records, we collected information about the mothers and newborns.

Results: Mean (SE) adiponectin concentrations in breast milk were 13.7 (0.8), range 3.9–30.4 μg/L; AFABP concentrations 26.7 (4.4), range 1.2–137.0 μg/L; EFABP concentrations 18.1 (1.4), range 0.8–47.0 μg/L; and leptin concentrations 0.50 (0.05), range 0–1.37 μg/L. We found a significant correlation between AFABP and EFABP concentrations (r = 0.593, P &lt;0.0001). Maternal EFABP concentrations were significantly higher in mothers who delivered boys than in those who delivered girls [21.7 (2.3) vs 15.4 (1.7) μg/L, P = 0.028] and correlated with newborn birth weight (r = 0.266, P = 0.045). Maternal leptin correlated with body weight before pregnancy (r = 0.272, P = 0.043) and at delivery (r = 0.370, P = 0.005), body mass index before pregnancy (r = 0.397, P = 0.003) and at delivery (r = 0.498, P &lt;0.0001), body weight gain during pregnancy (r = 0.267, P = 0.047), and newborn gestational age (r = 0.266, P = 0.048). Leptin was significantly lower in mothers who delivered preterm vs term babies [0.30 (0.09) vs 0.60 (0.05) ug/L, P = 0.026].

Conclusions: Concentrations of adiponectin, AFABP, and EFABP in human breast milk are related to nutritional variables of mothers and newborns and thus may play a role in the protective effects of breastfeeding.

Sex-discordant associations with adiponectin levels and lipid profiles in children

In adults, lower circulating levels of the adipocyte-derived hormone adiponectin are associated with obesity, type 2 diabetes, and cardiovascular disease risks. Its use as a risk marker in children is less clear. In 839 children aged 8 years from a representative birth cohort, circulating adiponectin levels were associated with body weight, BMI, waist circumference, and fasting and 30-min insulin levels, but the associations were opposite in boys, with positive associations, and girls, with inverse associations (P = 0.008-0.00001 for interaction with sex). Girls had overall higher adiponectin, higher total cholesterol, lower HDL cholesterol, and higher triglyceride levels than boys, even after adjustment for BMI. With increasing BMI, girls showed steeper declines in HDL cholesterol (P = 0.01 for interaction) and adiponectin levels (P = 0.0005 for interaction) and a steeper increase in triglyceride levels (P = 0.009 for interaction) compared with boys. In conclusion, plasma adiponectin is not a simple marker of central fat and insulin sensitivity in children. With increasing BMI, decreasing adiponectin levels in girls could contribute to their faster deterioration in lipid profiles in comparison with boys. Our data suggest a complex age- and sex-related regulation of adiponectin secretion or clearance.

Longitudinal changes in insulin sensitivity and secretion from birth to age three years in small- and appropriate-for-gestational-age children

AIMS/HYPOTHESIS

Insulin resistance and type 2 diabetes risk in human subjects who were small-for-gestational-age (SGA) at birth may be a consequence of rapid early postnatal weight gain.

MATERIALS AND METHODS

We prospectively studied early changes in fasting insulin sensitivity and insulin secretion, assessed by a short intravenous glucose tolerance test that was conducted several times from birth to 3 years of age in 55 SGA (birthweight below fifth percentile) newborns and in 13 newborns with a birthweight appropriate for gestational age (AGA).

RESULTS

Most SGA infants showed postnatal upward weight centile crossing and by 3 years were similar in size to AGA infants. SGA infants had lower pre-feed insulin levels at postnatal age 48 h than AGA infants (median 34.4 vs 59.7 pmol/l, p<0.05), but by the age of 3 years they had higher fasting insulin levels (median 38.9 vs 23.8 pmol/l, p<0.005), which were related to rate of weight gain between 0 and 3 years (r=0.47, p=0.0003). First-phase insulin secretion did not differ between SGA and AGA infants, but SGA infants had a lower glucose disposition index (beta cell compensation) (median 235 vs 501 min mmol(-1) l(-1), p=0.02), which persisted after allowing for postnatal weight gain (p=0.009).

CONCLUSIONS/INTERPRETATION

SGA infants showed a marked transition from lower pre-feed insulin and increased insulin sensitivity at birth to insulin resistance over the first 3 years of life. This transition was related to rapid postnatal weight gain, which could indicate a propensity to central fat deposition. The additional observation of reduced compensatory beta cell secretion underlines the need for long-term surveillance of glucose homeostasis in all SGA subjects, whether or not they show postnatal catch-up growth.