Longitudinal changes in adipokines and free leptin index during and after pregnancy in women with obesity

Glucose tolerance two years after gestational diabetes classified by old Swedish or new WHO diagnostic criteria

AIM

To explore how introduction of the lower WHO gestational diabetes (GDM) glucose criteria in Sweden affected prediabetes/type-2-diabetes (T2D) incidence two years postpartum.

METHODS

Women included in the PREvention of PostPartum (PREPP) diabetes study were diagnosed with GDM according to EASD 1991 criteria (GDMOLD; n = 93) or only WHO 2013 criteria (GDMWHO; n = 174). Both groups were further stratified by BMI, and BMI-matched normoglycemic pregnancy controls were included (n = 88). Postpartum assessments included oral glucose tolerance tests (OGTT) and anthropometric measurements.

RESULTS

There was a higher postpartum incidence of T2D in GDMOLD versus GDMWHO (P < 0.001). Despite similar BMI, GDMOLD exhibited higher fasting and OGTT glucose levels, lower fat-free-mass, and hip circumference compared to GDMWHO. In normal-weight women, both GDM groups displayed higher HOMA-IR and lower fat-free-mass compared to controls, with GDMOLD additionally showing lower HOMA-β, slower insulin release during OGTT, and worse glucose tolerance than GDMWHO. Among obese women, the main differences were lower fat-free-mass and hip circumference in GDMOLD.

CONCLUSION

The lower glucose cut-offs during pregnancy resulted in lower postpartum incidence of T2D, irrespective of BMI. Fat-free-mass emerged as a key determinant in glucose levels across BMI categories, while lower beta-cell function played a significant role in normal-weight women.

Total Gestational Weight Gain Is Explained by Leptin and Body Fat, Regardless of Pre-Pregnancy Body Mass Index and Other Adipokines, in Mexican Adolescents

Pre-pregnancy body mass index (pBMI) is a predictor of gestational weight gain (GWG). However, other factors, such as adipokines and inflammation markers, may also be associated with GWG. The aim of the study was to determine the association of leptin, adiponectin, irisin, and C-reactive protein, with GWG in adolescents. A longitudinal study was conducted from 2018 to 2023 in adolescents with a clinically healthy pregnancy. The assessments included sociodemographic and clinical data, pBMI, percent of body fat, serum concentrations of leptin, adiponectin, irisin, and high-sensitivity C-reactive protein (hsCRP), and total GWG adequacy. Cox regression models were performed, the outcome variables were inadequate and excessive GWG. In 198 participants, being overweight/obesity was marginally associated with a protective effect against inadequate GWG (HR = 0.44, 95%CI = 0.18-1.06), regardless of maternal characteristics and adipokines. Leptin (HR = 1.014, 95%CI = 1.008-1.021), and body fat percent (HR = 1.11, 95%CI = 1.05-1.17) were associated with a higher risk of excessive GWG, independent of other maternal variables such as pBMI, while adiponectin was associated with a lower risk. These findings suggest that, in Mexican adolescents, adipose tissue and its adipokines during pregnancy may play a more significant role in the final GWG than body weight.

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Maternal early mid-pregnancy adiponectin in relation to infant birth weight and the likelihood of being born large-for-gestational-age

This study aimed to evaluate the association of maternal adiponectin with infant birth size in 1349 pregnant women at Uppsala University Hospital, Sweden. The mean age of the women was 31.0 years, and 40.9% were nulliparous. Maternal early mid-pregnancy adiponectin was measured in microgram/mL. Linear regression models were performed to evaluate the association between adiponectin and infant birth weight. Logistic regression models were used to evaluate adiponectin in relation to the odds of giving birth to an infant large-for-gestational-age (LGA, infant birth weight standard deviation score > 90th percentile). Adjustments were made for early pregnancy BMI and diabetes mellitus. Prior adjustments, adiponectin was inversely associated with infant birth weight (β - 17.1, 95% confidence interval (CI) - 26.8 to - 7.4 g, P < 0.001), and one microgram/mL increase in adiponectin was associated with a 9% decrease in the odds of giving birth to an LGA infant (odds ratio 0.91, CI 0.85-0.97, P = 0.006). The associations did not withstand in the adjusted models. We found a significant interaction between adiponectin and infant sex on birth size. This interaction was driven by an inverse association between maternal adiponectin and birth size in female infants, whereas no such association was found in males.

Excessive Pregestational Weight and Maternal Obstetric Complications: The Role of Adipokines

There is a high frequency of overweight and obesity in women of reproductive age. Women who start pregnancy with overweight or obesity have an increased risk of developing maternal obstetric complications such as gestational hypertension, pre-eclampsia, gestational diabetes mellitus, postpartum hemorrhage, and requiring C-section to resolve the pregnancy with a higher risk of C-section surgical site infection. Excessive weight in pregnancy is characterized by dysregulation of adipokines, the functions of which partly explain the predisposition of pregnant women with overweight or obesity to these maternal obstetric complications. This review compiles, organizes, and analyzes the most recent studies on adipokines in pregnant women with excess weight and the potential pathophysiological mechanisms favoring the development of maternal pregnancy complications.

Periconceptional biomarkers for maternal obesity: a systematic review

Periconceptional maternal obesity is linked to adverse maternal and neonatal outcomes. Identifying periconceptional biomarkers of pathways affected by maternal obesity can unravel pathophysiologic mechanisms and identify individuals at risk of adverse clinical outcomes. The literature was systematically reviewed to identify periconceptional biomarkers of the endocrine, inflammatory and one-carbon metabolic pathways influenced by maternal obesity. A search was conducted in Embase, Ovid Medline All, Web of Science Core Collection and Cochrane Central Register of Controlled Trials databases, complemented by manual search in PubMed until December 31^st, 2020. Eligible studies were those that measured biomarker(s) in relation to maternal obesity, overweight/obesity or body mass index (BMI) during the periconceptional period (14 weeks preconception until 14 weeks post conception). The ErasmusAGE score was used to assess the quality of included studies. Fifty-one articles were included that evaluated over 40 biomarkers. Endocrine biomarkers associated with maternal obesity included leptin, insulin, thyroid stimulating hormone, adiponectin, progesterone, free T4 and human chorionic gonadotropin. C-reactive protein was associated with obesity as part of the inflammatory pathway, while the associated one-carbon metabolism biomarkers were folate and vitamin B12. BMI was positively associated with leptin, C-reactive protein and insulin resistance, and negatively associated with Free T4, progesterone and human chorionic gonadotropin. Concerning the remaining studied biomarkers, strong conclusions could not be established due to limited or contradictory data. Future research should focus on determining the predictive value of the optimal set of biomarkers for their use in clinical settings. The most promising biomarkers include leptin, adiponectin, human chorionic gonadotropin, insulin, progesterone and CRP.

Adiponectin Deficiency Alters Placenta Function but Does Not Affect Fetal Growth in Mice

Adiponectin administration to pregnant mice decreases nutrient transport and fetal growth. An adiponectin deficiency, on the other hand, as seen in obese women during pregnancy, alters fetal growth; however, the mechanism is unclear. To determine the role of adiponectin on placenta function and fetal growth, we used adiponectin knockout, adiponectin heterozygote that displays reduced adiponectin levels, and wild-type mice on a control diet or high fat/high sucrose (HF/HS) diet. Triglycerides (TGs) in the serum, liver, and placenta were measured using colorimetric assays. Gene expression was measured using quantitative RT-PCR. Adiponectin levels did not affect fetal weight, but it reduced adiponectin levels, increased fetal serum and placenta TG content. Wildtype dams on a HF/HS diet protected the fetuses from fatty acid overload as judged by increased liver TGs in dams and normal serum and liver TG levels in fetuses, while low adiponectin was associated with increased fetal liver TGs. Low maternal adiponectin increased the expression of genes involved in fatty acid transport; Lpl and Cd36 in the placenta. Adiponectin deficiency does not affect fetal growth but induces placental dysfunction and increases fetal TG load, which is enhanced with obesity. This could lead to imprinting effects on the fetus and the development of metabolic dysfunction in the offspring.

Research Advances in the Roles of Circular RNAs in Pathophysiology and Early Diagnosis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) refers to different degrees of glucose tolerance abnormalities that occur during pregnancy or are discovered for the first time, which can have a serious impact on the mother and the offspring. The screening of GDM mainly relies on the oral glucose tolerance test (OGTT) at 24–28 weeks of gestation. The early diagnosis and intervention of GDM can greatly improve adverse pregnancy outcomes. However, molecular markers for early prediction and diagnosis of GDM are currently lacking. Therefore, looking for GDM-specific early diagnostic markers has important clinical significance for the prevention and treatment of GDM and the management of subsequent maternal health. Circular RNA (circRNA) is a new type of non-coding RNA. Recent studies have found that circRNAs were involved in the occurrence and development of malignant tumors, metabolic diseases, cardiovascular and cerebrovascular diseases, etc., and could be used as the molecular marker for early diagnosis. Our previous research showed that circRNAs are differentially expressed in serum of GDM pregnant women in the second and third trimester, placental tissues during cesarean delivery, and cord blood. However, the mechanism of circular RNA in GDM still remains unclear. This article focuses on related circRNAs involved in insulin resistance and β-cell dysfunction, speculating on the possible role of circRNAs in the pathophysiology of GDM under the current research context, and has the potential to serve as early molecular markers for the diagnosis of GDM.

Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: A longitudinal, placebo-controlled study

OBJECTIVE

To explore mechanisms that modulate gestational weight gain (GWG) in women with polycystic ovary syndrome (PCOS) and healthy controls.

DESIGN

Sub-sample of randomised controlled trials (PCOS) combined with a prospective cohort (controls).

SETTING

Eleven Norwegian, Swedish, and Icelandic hospitals.

POPULATION

Pregnant women with PCOS treated with metformin (PCOS-M, n = 36) or placebo (PCOS-P, n = 37), and healthy pregnant women (HC, n = 15).

METHODS

Serum levels of the appetite regulating hormones leptin, ghrelin, allopregnanolone, and soluble leptin receptor (sOB-R) were determined in the first and third trimesters.

MAIN OUTCOME MEASURES

Excessive GWG (eGWG) relative to body mass index according to Institute of Medicine (IOM) guideline. Serum leptin/sOB-R ratio, or free-leptin-index (FLI), as biomarker of leptin sensitivity. Serum ghrelin and allopregnanolone levels.

RESULTS

The overall prevalence of eGWG was 44% (38/86). Women with eGWG had higher first and third trimester FLI (P < 0.001), and lower third trimester allopregnanolone levels (P = 0.003) versus women with non-eGWG. The prevalence of eGWG was lower in PCOS-M versus PCOS-P (28% versus 62%, odds ratio = 0.4, 95% CI 0.2-0.8, P = 0.005). FLI decreased during pregnancy in PCOS-M (P = 0.01), but remained unaltered in PCOS-P and HC. Ghrelin and allopregnanolone levels were comparable in PCOS-M, PCOS-P and HC throughout pregnancy.

CONCLUSION

Excessive GWG is associated with enhanced leptin resistance, and attenuated physiological increase in serum allopregnanolone levels during pregnancy. Metformin reduces the risk for eGWG and improves leptin sensitivity in pregnant women with PCOS.

Longitudinal changes in circulating concentrations of inflammatory markers throughout pregnancy: are there associations with diet and weight status?

The natural inflammation occurring during pregnancy can, under certain conditions, be associated with adverse pregnancy outcomes. This study aimed to: 1) quantify changes in circulating concentrations of leptin, adiponectin, interleukin-6 (IL-6) and C-reactive protein (CRP) across trimesters of pregnancy, according to pre-pregnancy body mass index (ppBMI); and 2) examine the trimester-specific associations between the inflammatory markers' concentrations, a Mediterranean diet score (MDS) and the dietary inflammatory index (DII). We measured leptin, adiponectin and IL-6 by ELISA, and CRP by high-sensitivity immunonephelometry, in blood samples from 79 pregnant women (age: 32.1 ± 3.7 years; ppBMI: 25.7 ± 5.8 kg/m2). Three web-based 24h recalls were completed at each trimester and used to compute the MDS and the DII. CRP concentrations remained stable across trimesters, whereas concentrations of leptin and IL-6 increased, and adiponectin concentrations decreased (p<0.001). Changes in leptin and adiponectin concentrations also differed according to ppBMI categories (p<0.05). As for the dietary scores, the only significant association was observed in the second trimester between leptin concentrations and the MDS (r=-0.26, p<0.05). In conclusion, ppBMI and the progression of pregnancy itself probably supplant the potential associations between diet and the inflammation occurring during that period. Novelty: • Circulating leptin and IL-6 concentrations increased across trimesters whereas CRP was stable, and adiponectin decreased. • Variations in circulating leptin and adiponectin concentrations differed by ppBMI categories. • Very few associations were observed between dietary scores and inflammatory markers.

Growth-differentiation-factor 15 levels in obese and healthy pregnancies: Relation to insulin resistance and insulin secretory function

OBJECTIVE/AIM

Growth-differentiation-factor 15 (GDF15) has been suggested to improve or protect beta cell function. During pregnancy, beta cell numbers and function increase to overcome the natural rise in insulin resistance during gestation. In this study, we longitudinally measured serum GDF15 levels during and after pregnancy in women of normal weight (NW) and in women with obesity (OB) and explored associations between GDF15 and changes in beta cell function by homeostatic model assessment (HOMA).

METHODS

The cohort participants were 38 NW (BMI 22.3 ± 1.7) and 35 OB (BMI 35.8 ± 4.2). Blood was sampled and body composition measured at each trimester (T1, T2, and T3) and at 6, 12 and 18 months postpartum. Fasting glucose, insulin and GDF15 were measured, and HOMA for insulin resistance (HOMA-IR) and beta cell function (HOMA-B) determined.

RESULTS

GDF15 levels increased significantly each trimester and were ~200-fold higher at T3 than in the nonpregnant postpartum state. GDF15 was higher in NW than OB during pregnancy, but was reversed after pregnancy with a significant interaction effect. GDF15 correlated inversely with BMI and fat-free mass at T3. Low GDF15 was associated with lower incidence of nausea and with carrying a male foetus. The pregnancy induced increase in GDF15 associated with increased HOMA-B in OB and with reduced fasting glucose in all women.

CONCLUSION

Large gestational upregulation of GDF15 levels may help increase insulin secretory function to overcome pregnancy-induced insulin resistance.

Physical activity during pregnancy and association with changes in fat mass and adipokines in women of normal-weight or with obesity

Adipose tissue and adipokine concentrations change markedly during pregnancy, but the effects of physical activity on these changes are rarely studied. We aimed to assess physical activity levels in pregnant women of normal-weight (NW) or with obesity (OB), and to determine the relation with changes in fat mass and adipokines. In each trimester, pregnant women (136 NW, 51 OB) were interviewed about their physical activity and had their body composition, leptin, soluble leptin receptor (sOB-R) and adiponectin determined. NW reported higher activity and more aerobic exercise than OB during early pregnancy. Both groups maintained training frequency but reduced overall activity as pregnancy progressed. NW women reporting aerobic and/or resistance exercise and OB women reporting aerobic exercise had greater sOB-R increases (independent of BMI or gestational weight gain). In NW, exercise also associated with lower fat mass and leptin increases. Higher activity levels associated with lower gestational weight gain in both groups. The relationship between physical activity and adiponectin differed between NW and OB. Maternal exercise may partly mediate its beneficial effects through regulation of leptin bioavailability, by enhancing pregnancy-induced increases in sOB-R. This could be of particular importance in OB with pre-gestational hyperleptinemia and leptin resistance.

Growth differentiation factor 15 increases in both cerebrospinal fluid and serum during pregnancy

Aim

Growth differentiation factor 15 (GDF15) increases in serum during pregnancy to levels not seen in any other physiological state and is suggested to be involved in pregnancy-induced nausea, weight regulation and glucose metabolism. The main action of GDF15 is regulated through a receptor of the brainstem, i.e., through exposure of GDF15 in both blood and cerebrospinal fluid (CSF). The aim of the current study was to measure GDF15 in both CSF and serum during pregnancy, and to compare it longitudinally to non-pregnant levels.

Methods

Women were sampled at elective caesarean section (n = 45, BMI = 28.1±5.0) and were followed up 5 years after pregnancy (n = 25). GDF15, insulin and leptin were measured in CSF and serum. Additional measurements included plasma glucose, and serum adiponectin and Hs-CRP.

Results

GDF15 levels were higher during pregnancy compared with follow-up in both CSF (385±128 vs. 115±32 ng/l, P<0.001) and serum (73789±29198 vs. 404±102 ng/l, P<0.001). CSF levels correlated with serum levels during pregnancy (P<0.001), but not in the non-pregnant state (P = 0.98). Both CSF and serum GDF15 were highest in women carrying a female fetus (P<0.001). Serum GDF15 correlated with the homeostatic model assessment for beta-cell function and placental weight, and CSF GDF15 correlated inversely with CSF insulin levels.

Conclusion

This, the first study to measure CSF GDF15 during pregnancy, demonstrated increased GDF15 levels in both serum and CSF during pregnancy. The results suggest that effects of GDF15 during pregnancy can be mediated by increases in both CSF and serum levels.

Infant body composition relationship to maternal adipokines and fat mass: the PONCH study

BACKGROUND

Infant adiposity is linked to both high maternal fat mass (FM) and excessive gestational FM gain, whereas the association with maternal adipokines is less clear. The aim was to determine how levels of maternal leptin, the soluble leptin receptor (sOB-R), adiponectin, and FM during pregnancy were linked to infant FM in normal-weight (NW) women and women with obesity (OB).

METHODS

Body composition and serum levels of leptin, adiponectin, and sOB-R were determined three times during pregnancy in 80 NW and 46 OB women. For infants, body composition was measured at 1 and 12 weeks of age.

RESULTS

Maternal leptin and sOB-R levels increased during pregnancy. For NW women, infant FM at 1 week was inversely associated with changes in maternal leptin and at 12 weeks inversely associated with absolute maternal sOB-R levels throughout pregnancy, as well as changes in sOB-R levels in early pregnancy. For OB women, infant FM at both 1 and 12 weeks were best explained by maternal FM.

CONCLUSIONS

Leptin and sOB-R, thought to regulate leptin bioavailability, are associated with fat accumulation in infants born to NW women. In OB women, maternal FM in early pregnancy is more important than leptin in determining infant fat accumulation.

IMPACT

In normal-weight women, the regulation of maternal leptin bioavailability during pregnancy has a role in infant fat mass accumulation. In women with obesity, however, pre-pregnancy maternal fat mass seems more important for infant fat mass. This is the first study of maternal adipokines and fat mass including longitudinal measurements in both mothers and their children. Understanding the relationship between maternal factors and infant fat mass is of great importance as obesity is programmed over the generations, and it is important to learn what regulates this programming.

The effect of postpartum period back massage on serum ghrelin, leptin, adiponectin and visfatin levels

In addition to the initiation and continuity of lactation, hormones transferred from mother plasma to milk during breastfeeding are also important. The aim of this study was to determine the effect of back massage on maternal serum ghrelin, leptin, adiponectin and visfatin levels in women giving birth. A total of 60 mothers, participated in this experimental study. Massage was applied in the first 3-4 h after birth. Blood sample was taken in the postnatal routine. It was determined that the intervention group did not make a statistically significant difference in ghrelin (1.37 ± 0.7, 1.00 ± 0.2), leptin (0.76 ± 0.5, 0.70 ± 0.1), adiponectin (3.55 ± 0.8, 3.05 ± 0.5) levels compared to the control group (p > 0.05). However, visfatin (10.53 ± 2.4, 9.97 ± 2.0) levels were statistically higher than the control group (p < 0.05). Back massage was found to be beneficial in terms of increased growth factors in breast milk production and content.