Macrophage inhibitory cytokine-1 in gestational tissues and maternal serum in normal and pre-eclamptic pregnancy

GDF-15 Alleviates Hypoxia-Reoxygenation-Induced Damage to Human Placental Vascular Endothelial Cells by Regulating SIRT1

OBJECTIVE

Pregnancy-induced hypertension (PIH) is a common disease during pregnancy, which arises from maternal placental vascular endothelial cell dysfunction. Growth differentiation factor 15 (GDF-15) has a protective effect on the cardiovascular system. The purpose of this study is to explore the protective effect of GDF-15 against hypoxia-reoxygenation (H/R)-induced damage to human placental vascular endothelial cells (HPVECs) and the regulatory mechanism of SIRT1 in this effect.

METHODS

Serum samples from healthy pregnant women and those with PIH were collected, and their GDF-15 and SIRT1 levels were examined. HPVECs were cultured in vitro and induced with H/R and GDF-15 at varying concentrations. The optimal concentration of GDF-15 in protecting HPVECs was determined by measuring cell viability via the CCK-8 assay. In H/R-induced HPVECs treated with GDF-15 and compound C (the AMPK inhibitor), expression levels of SIRT1, p-AMPK, and t-AMPK were detected. Cell apoptosis was examined by flow cytometry.

RESULTS

Serum SIRT1 and GDF-15 were significantly higher in healthy pregnant women than in PIH patients. Suppressed viability and activated apoptosis in H/R-induced HPVECs were partially reversed by the treatment of GDF-15 at a concentration of 100 ng/mL. H/R induction significantly downregulated SIRT1 and p-AMPK in HPVECs, which were then upregulated by GDF-15. Moreover, the protective effect of GDF-15 on H/R-induced HPVECs was blocked by inhibiting the AMPK signaling pathway.

CONCLUSION

GDF-15 protects against H/R-inhibited cell viability and H/R-stimulated apoptosis in HPVECs by activating the AMPK signaling pathway to upregulate SIRT1.

TGFβ signalling: a nexus between inflammation, placental health and preeclampsia throughout pregnancy

BACKGROUND

The placenta is a unique and pivotal organ in reproduction, controlling crucial growth and cell differentiation processes that ensure a successful pregnancy. Placental development is a tightly regulated and dynamic process, in which the transforming growth factor beta (TGFβ) superfamily plays a central role. This family of pleiotropic growth factors is heavily involved in regulating various aspects of reproductive biology, particularly in trophoblast differentiation during the first trimester of pregnancy. TGFβ signalling precisely regulates trophoblast invasion and the cell transition from cytotrophoblasts to extravillous trophoblasts, which is an epithelial-to-mesenchymal transition-like process. Later in pregnancy, TGFβ signalling ensures proper vascularization and angiogenesis in placental endothelial cells. Beyond its role in trophoblasts and endothelial cells, TGFβ signalling contributes to the polarization and function of placental and decidual macrophages by promoting maternal tolerance of the semi-allogeneic foetus. Disturbances in early placental development have been associated with several pregnancy complications, including preeclampsia (PE) which is one of the severe complications. Emerging evidence suggests that TGFβ is involved in the pathogenesis of PE, thereby offering a potential target for intervention in the human placenta.

OBJECTIVE AND RATIONALE

This comprehensive review aims to explore and elucidate the roles of the major members of the TGFβ superfamily, including TGFβs, bone morphogenetic proteins (BMPs), activins, inhibins, nodals, and growth differentiation factors (GDFs), in the context of placental development and function. The review focusses on their interactions within the major cell types of the placenta, namely trophoblasts, endothelial cells, and immune cells, in both normal pregnancies and pregnancies complicated by PE throughout pregnancy.

SEARCH METHODS

A literature search was carried out using PubMed and Google Scholar, searching terms: 'TGF signalling preeclampsia', 'pregnancy TGF signalling', 'preeclampsia tgfβ', 'preeclampsia bmp', 'preeclampsia gdf', 'preeclampsia activin', 'endoglin preeclampsia', 'endoglin pregnancy', 'tgfβ signalling pregnancy', 'bmp signalling pregnancy', 'gdf signalling pregnancy', 'activin signalling pregnancy', 'Hofbauer cell tgfβ signalling', 'placental macrophages tgfβ', 'endothelial cells tgfβ', 'endothelium tgfβ signalling', 'trophoblast invasion tgfβ signalling', 'trophoblast invasion Smad', 'trophoblast invasion bmp', 'trophoblast invasion tgfβ', 'tgfβ preeclampsia', 'tgfβ placental development', 'TGFβ placental function', 'endothelial dysfunction preeclampsia tgfβ signalling', 'vascular remodelling placenta TGFβ', 'inflammation pregnancy tgfβ', 'immune response pregnancy tgfβ', 'immune tolerance pregnancy tgfβ', 'TGFβ pregnancy NK cells', 'bmp pregnancy NK cells', 'bmp pregnancy tregs', 'tgfβ pregnancy tregs', 'TGFβ placenta NK cells', 'TGFβ placenta tregs', 'NK cells preeclampsia', 'Tregs preeclampsia'. Only articles published in English until 2023 were used.

OUTCOMES

A comprehensive understanding of TGFβ signalling and its role in regulating interconnected cell functions of the main placental cell types provides valuable insights into the processes essential for successful placental development and growth of the foetus during pregnancy. By orchestrating trophoblast invasion, vascularization, immune tolerance, and tissue remodelling, TGFβ ligands contribute to the proper functioning of a healthy maternal-foetal interface. However, dysregulation of TGFβ signalling has been implicated in the pathogenesis of PE, where the shallow trophoblast invasion, defective vascular remodelling, decreased uteroplacental perfusion, and endothelial cell and immune dysfunction observed in PE, are all affected by an altered TGFβ signalling.

WIDER IMPLICATIONS

The dysregulation of TGFβ signalling in PE has important implications for research and clinical practice. Further investigation is required to understand the underlying mechanisms, including the role of different ligands and their regulation under pathophysiological conditions, in order to discover new therapeutic targets. Distinguishing between clinically manifested subtypes of PE and studying TGFβ signalling in different placental cell types holistically is an important first step. To put this knowledge into practice, pre-clinical animal models combined with new technologies are needed. This may also lead to improved human research models and identify potential therapeutic targets, ultimately improving outcomes for affected pregnancies and reducing the burden of PE.

Hyperemesis gravidarum theories dispelled by recent research: a paradigm change for better care and outcomes

Nausea and vomiting (NVP) affect most pregnant women. At the severe end of the clinical spectrum, hyperemesis gravidarum (HG) can be life-threatening. The condition is fraught with misconceptions that have slowed progress and left women undertreated. Herein, recent scientific advances are presented that dispel common myths associated with HG related to maternal/offspring outcomes, etiology, and evolution. There is now strong evidence that (i) HG is associated with poor outcomes, (ii) a common cause of NVP and HG has been identified, and (iii) NVP is likely a protective evolutionary mechanism that occurs throughout the animal kingdom but is no longer necessary for human survival. Therefore, it is encouraging that we are finally on the cusp of testing treatments that may put an end to unnecessary suffering.

Association between plasma growth differentiation factor 15 levels and pre-eclampsia in China

Background

Growth differentiation factor-15 (GDF-15) is a stress response protein and is related to cardiovascular diseases (CVD). This study aimed to investigate the association between GDF-15 and pre-eclampsia (PE).

Method

The study involved 299 pregnant women, out of which 236 had normal pregnancies, while 63 participants had PE. Maternal serum levels of GDF-15 were measured by using enzyme-linked immunosorbent assay kits and then translated into multiple of median (MOM) to avoid the influence of gestational week at blood sampling. Logistic models were performed to estimate the association between GDF-15 MOM and PE, presenting as odd ratios (ORs) and 95% confidence intervals (CIs).

Results

MOM of GDF-15 in PE participants was higher compared with controls (1.588 vs. 1.000, p < 0.001). In the logistic model, pregnant women with higher MOM of GDF-15 (>1) had a 4.74-fold (95% CI = 2.23-10.08, p < 0.001) increased risk of PE, adjusted by age, preconceptional body mass index, gravidity, and parity.

Conclusions

These results demonstrated that higher levels of serum GDF-15 were associated with PE. GDF-15 may serve as a biomarker for diagnosing PE.

GDF15, an Emerging Player in Renal Physiology and Pathophysiology

These last years, the growth factor GDF15 has emerged as a key element in many different biological processes. It has been established as being produced in response to many pathological states and is now referred to as a stress-related hormone. Regarding kidney functions, GDF15 has been involved in different pathologies such as chronic kidney disease, diabetic nephropathy, renal cancer, and so on. Interestingly, recent studies also revealed a role of GDF15 in the renal homeostatic mechanisms allowing to maintain constant, as far as possible, the plasma parameters such as pH and K+ values. In this review, we recapitulate the role of GDF15 in physiological and pathological context by focusing our interest on its renal effect.

GDF15 knockout does not substantially impact perinatal body weight or neonatal outcomes in mice

Growth differentiation factor-15 (GDF15) increases in circulation during pregnancy and has been implicated in food intake, weight loss, complications of pregnancy, and metabolic illness. We used a Gdf15 knockout mouse model (Gdf15-/- ) to assess the role of GDF15 in body weight regulation and food intake during pregnancy. We found that Gdf15-/- dams consumed a similar amount of food and gained comparable weight during the course of pregnancy compared to Gdf15+/+ dams. Insulin sensitivity on gestational day 16.5 was also similar between genotypes. In the postnatal period, litter size, and survival rates were similar between genotypes. There was a modest reduction in birth weight of Gdf15-/- pups, but this difference was no longer evident postnatal day 3.5 to 14.5. We observed no detectable differences in milk volume production or milk fat percentage. These data suggest that GDF15 is dispensable for changes in food intake, and body weight as well as insulin sensitivity during pregnancy in a mouse model.

Roles of bone morphogenetic proteins in endometrial remodeling during the human menstrual cycle and pregnancy

BACKGROUND

During the human menstrual cycle and pregnancy, the endometrium undergoes a series of dynamic remodeling processes to adapt to physiological changes. Insufficient endometrial remodeling, characterized by inadequate endometrial proliferation, decidualization and spiral artery remodeling, is associated with infertility, endometriosis, dysfunctional uterine bleeding, and pregnancy-related complications such as preeclampsia and miscarriage. Bone morphogenetic proteins (BMPs), a subset of the transforming growth factor-β (TGF-β) superfamily, are multifunctional cytokines that regulate diverse cellular activities, such as differentiation, proliferation, apoptosis, and extracellular matrix synthesis, are now understood as integral to multiple reproductive processes in women. Investigations using human biological samples have shown that BMPs are essential for regulating human endometrial remodeling processes, including endometrial proliferation and decidualization.

OBJECTIVE AND RATIONALE

This review summarizes our current knowledge on the known pathophysiological roles of BMPs and their underlying molecular mechanisms in regulating human endometrial proliferation and decidualization, with the goal of promoting the development of innovative strategies for diagnosing, treating and preventing infertility and adverse pregnancy complications associated with dysregulated human endometrial remodeling.

SEARCH METHODS

A literature search for original articles published up to June 2023 was conducted in the PubMed, MEDLINE, and Google Scholar databases, identifying studies on the roles of BMPs in endometrial remodeling during the human menstrual cycle and pregnancy. Articles identified were restricted to English language full-text papers.

OUTCOMES

BMP ligands and receptors and their transduction molecules are expressed in the endometrium and at the maternal-fetal interface. Along with emerging technologies such as tissue microarrays, 3D organoid cultures and advanced single-cell transcriptomics, and given the clinical availability of recombinant human proteins and ongoing pharmaceutical development, it is now clear that BMPs exert multiple roles in regulating human endometrial remodeling and that these biomolecules (and their receptors) can be targeted for diagnostic and therapeutic purposes. Moreover, dysregulation of these ligands, their receptors, or signaling determinants can impact endometrial remodeling, contributing to infertility or pregnancy-related complications (e.g. preeclampsia and miscarriage).

WIDER IMPLICATIONS

Although further clinical trials are needed, recent advancements in the development of recombinant BMP ligands, synthetic BMP inhibitors, receptor antagonists, BMP ligand sequestration tools, and gene therapies have underscored the BMPs as candidate diagnostic biomarkers and positioned the BMP signaling pathway as a promising therapeutic target for addressing infertility and pregnancy complications related to dysregulated human endometrial remodeling.

Evaluation of nausea and vomiting in the first trimester on the risk of adverse birth outcomes and the contribution of genetic polymorphisms: a pilot prospective study

PURPOSE

To evaluate the impact of Nausea and Vomiting in Pregnancy (NVP) on the risk of Preterm Birth (PTB) and Low Birth Weight (LBW), and explore the effect of genetic polymorphisms on the severity of NVP.

METHODS

A prospective study was conducted. Participants' experience of NVP prior to 12 gestational weeks were evaluated by a Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) scale. 11 Single Nucleotide Polymorphisms (SNPs) loci located in growth differentiation factor 15 (GDF15) and leucine-rich repeat containing 25 (LRRC25) gene of chr19p13.11 and intergenic region of chr4q12 were genotyped, which were implicated as genetic risk factors for NVP. Logistic regression models were applied to determine the effect of NVP in the first trimester on the risk of PTB and LBW, and genetic polymorphisms on the risk of NVP.

RESULTS

Among 413 pregnant women, the incidence of nausea and vomiting was 85.5% (n = 353) in the first trimester, including 38.7% (n = 160) mild vomiting, 42.6% (n = 176) moderate vomiting and 4.1% (n = 17) severe vomiting. 33 were PTB, 20 were LBW. Compared with pregnant women without NVP, women with mild, moderate or severe NVP in the first trimester were not associated with the risk of PTB and LBW. Besides, the polymorphisms of 11 SNPs loci were not associated with the risk of NVP.

CONCLUSIONS

Our study indicated that symptoms of nausea and vomiting in the first trimester were not significantly associated with PTB and LBW, and there were also no associations between GDF15 and LRRC25 polymorphisms and NVP.

Cross-species comparison of pregnancy-induced GDF15

Growth differentiation factor 15 (GDF15) is a stress-induced cytokine. Although the exact physiological function of GDF15 is not yet fully comprehended, the significant elevation of circulating GDF15 levels during gestation suggests a potential role for this hormone in pregnancy. This is corroborated by genetic association studies in which GDF15 and the GDF15 receptor, GDNF family receptor alpha like (GFRAL) have been linked to morning sickness and hyperemesis gravidarum (HG) in humans. Here, we studied GDF15 biology during pregnancy in mice, rats, macaques, and humans. In contrast to macaques and humans, mice and rats exhibited an underwhelming induction in plasma GDF15 levels in response to pregnancy (∼75-fold increase in macaques vs. ∼2-fold increase in rodents). The changes in circulating GDF15 levels were corroborated by the magnitude of Gdf15 mRNA and GDF15 protein expression in placentae from mice, rats, and macaques. These species-specific findings may help guide future studies focusing on GDF15 in pregnancy and on the evaluation of pharmacological strategies to interfere with GDF15-GFRAL signaling to treat severe nausea and HG.NEW & NOTEWORTHY In the present study pregnancy-induced changes in circulating growth differentiation factor 15 (GDF15) in rodents, rhesus macaques, and humans are mapped. In sum, it is demonstrated that humans and macaques exhibit a tremendous increase in placental and circulating GDF15 during pregnancy. In contrast, GDF15 is negligibly increased in pregnant mice and rats, questioning a physiological role for GDF15 in pregnancy in rodents.

Loss of growth differentiation factor 15 exacerbates lung injury in neonatal mice

Growth differentiation factor 15 (GDF15) is a divergent member of the transforming growth factor-β (TGF-β) superfamily, and its expression increases under various stress conditions, including inflammation, hyperoxia, and senescence. GDF15 expression is increased in neonatal murine bronchopulmonary dysplasia (BPD) models, and GDF15 loss exacerbates oxidative stress and decreases cellular viability in vitro. Our overall hypothesis is that the loss of GDF15 will exacerbate hyperoxic lung injury in the neonatal lung in vivo. We exposed neonatal Gdf15-/- mice and wild-type (WT) controls on a similar background to room air or hyperoxia (95% [Formula: see text]) for 5 days after birth. The mice were euthanized on postnatal day 21 (PND 21). Gdf15-/- mice had higher mortality and lower body weight than WT mice after exposure to hyperoxia. Hyperoxia exposure adversely impacted alveolarization and lung vascular development, with a greater impact in Gdf15-/- mice. Interestingly, Gdf15-/- mice showed lower macrophage count in the lungs compared with WT mice both under room air and after exposure to hyperoxia. Analysis of the lung transcriptome revealed marked divergence in gene expression and enriched biological pathways in WT and Gdf15-/- mice and differed markedly by biological sex. Notably, pathways related to macrophage activation and myeloid cell homeostasis were negatively enriched in Gdf15-/- mice. Loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice.NEW & NOTEWORTHY We show for the first time that loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice. We also highlight the distinct pulmonary transcriptomic response in the Gdf15-/- lung including pathways related to macrophage recruitment and activation.

Identification of menaquinone-4 (vitamin K2) target genes in bovine endometrial epithelial cells in vitro

The effect of vitamin K on bovine endometrial epithelial cells has not been thoroughly investigated. The objective of this study was to examine the effect of the biologically active form of vitamin K, menaquinone-4, on gene expression in bovine endometrial epithelial cells. First, we examined the mRNA and protein expression levels of UBIAD1, a menaquinone-4 biosynthetic enzyme. Second, we screened for potential target genes of menaquinone-4 in bovine endometrial epithelial cells using RNA-sequencing. We found 50 differentially expressed genes; 42 were upregulated, and 8 were downregulated. Among them, a dose-dependent response to menaquinone-4 was observed for the top three upregulated (TRIB3, IL6, and TNFAIP3) and downregulated (CDC6, ORC1, and RRM2) genes. It has been suggested that these genes play important roles in reproductive events. In addition, GDF15 and VEGFA, which are important for cellular functions as they are commonly involved in pathways, such as positive regulation of cell communication, cell differentiation, and positive regulation of MAPK cascade, were upregulated in endometrial epithelial cells by menaquinone-4 treatment. To the best of our knowledge, this is the first study showing the expression of UBIAD1 in the bovine uterus. Moreover, the study determined menaquinone-4 target genes in bovine endometrial epithelial cells, which may positively affect pregnancy with alteration of gene expression in cattle uterus.

Circulating Growth Differentiation Factor 15 and Preeclampsia: A Meta-Analysis

Growth differentiation factor 15 (GDF-15) has been suggested as a potential biomarker of preeclampsia. However, previous studies evaluating circulating GDF-15 in women with preeclampsia showed inconsistent results. A meta-analysis was performed accordingly in this study. Observational studies comparing circulating GDF-15 between women with preeclampsia normal pregnancy were identified by search of electronic databases including PubMed, Embase, Web of Science, Wanfang, and CNKI. The Newcastle-Ottawa Scale (NOS) was used for assessing the quality of the studies. A randomized-effect model incorporating the possible between-study heterogeneity was used to pool the results. Eleven observational studies including 498 women with preeclampsia and 2349 women with normal pregnancy contributed to the meta-analysis. Results showed that compared to controls of women with normal pregnancy at least matched for gestational ages, women with preeclampsia had significantly higher circulating GDF-15 at the diagnosis [standard mean difference (SMD): 0.66, 95% confidence interval (CI): 0.16 to 1.17, p=0.01, I2=93%]. Subgroup analysis showed consistent results in women with preterm and term preeclampsia in Asian and non-Asian women and in studies with different quality scores, which were not statistically significant between subgroups (p for subgroup difference>0.05). Moreover, a higher level of GDF-15 was also found before the diagnosis in women who subsequently developed preeclampsia than those who did not (SMD: 1.32, 95% CI: 0.45 to 2.18, p=0.003, I2=89%). In conclusion, a higher circulating GDF-15 is observed in women with preeclampsia even before the diagnosis of the disease.

Growth and differentiation factor 15 (GDF15) levels predict adverse respiratory outcomes in premature neonates

Growth and differentiation factor 15 (GDF15) is a stress-responsive cytokine, and its expression increases during inflammation, hyperoxia, and senescence. Significantly, GDF15 is secreted by the placenta, and maternal levels increase throughout pregnancy. Serum GDF15 level is a promising biomarker for many lung diseases like pulmonary hypertension and pulmonary fibrosis. However, circulating GDF15 levels in preterm infants and their role as a predictor of respiratory outcomes have not been studied. We hypothesized that GDF15 levels would increase with gestational age at birth, and that postnatal GDF15 will be correlated with adverse respiratory outcomes in preterm infants. Scavenged blood samples were retrieved from 57 preterm infants at five time points, from birth until 36-weeks postmenstrual age (PMA). GDF15 levels were measured using ELISA in 114 samples. We performed two-sample t-test, correlation and linear regression, logistic regression, and mixed-effects linear models for statistical analysis, and significance was identified when p < 0.05. Contrary to our hypothesis, for every 1-week increase in gestational age at birth, the predicted GDF15 level decreased by 475.0 pg/ml (p < 0.001). Greater PMA was significantly associated with lower serum GDF15 levels (p < 0.001). Interestingly, higher GDF15 levels were associated with a longer need for mechanical ventilation (p = 0.034), prolonged respiratory support need (p < 0.001), and length of hospital stay (p = 0.006). In conclusion, in preterm infants, GDF15 levels show an inverse correlation with gestational age at birth, with higher levels in more preterm babies, and levels trend down postnatally. Furthermore, longitudinal GDF15 levels through 36 weeks PMA predict adverse respiratory outcomes in preterm infants.

Whole-exome sequencing uncovers new variants in GDF15 associated with hyperemesis gravidarum

Whole‐exome sequencing reveals placenta and vomiting hormone GDF15 most likely cause of Hyperemesis Gravidarum.

Serum and urine profiles of TGF-β superfamily members in reproductive aged women

BACKGROUND

TGF-β superfamily members are important biomarkers of reproductive health in women desiring fertility and during pregnancy. TGF-β proteins derived from the ovary and/or placenta have been detected in serum in women, but there have been very few attempts to measure them non-invasively, such as in urinary samples, and to compare them to serum concentrations.

METHODS

We measured inhibin A, inhibin B, total inhibin, AMH, activin A, activin B, activin AB, follistatin, the GDF-9/BMP-15 complex, and GDF-15 in paired serum and urine samples from healthy reproductive aged women and in pregnant (second trimester) women.

RESULTS

We detected all hormones in serum in both pregnant and non-pregnant women. Inhibin A, total inhibin, activin A, activin AB, follistatin, and GDF-15 were significantly higher in pregnant than in non-pregnant women. GDF-15 was the only hormone consistently detected in urine. We also measured, for the first time, the GDF-9/BMP-15 functional heterodimer and the GDF-15 protein harboring the H202D polymorphism.

CONCLUSIONS

We report the successful measurement of the GDF-9/BMP-15 heterodimer (its native form) in serum and the ability to measure GDF-15 non-invasively, in urinary samples. This novel GDF-15 assay also captures the antigen in the presence of a common genetic variant.

Plasma GDF15 levels are similar between subjects after bariatric surgery and matched controls and are unaffected by meals

Growth differentiating factor 15 (GDF15) is expressed in the intestine and is one of the most recently identified satiety peptides. The mechanisms controlling its secretion are unclear. The present study investigated whether plasma GDF15 concentrations are meal-related and if potential responses depend on macronutrient type or are affected by previous bariatric surgery. The study included 1) volunteers ingesting rapidly vs. slowly digested carbohydrates (sucrose vs. isomaltose; n = 10), 2) volunteers who had undergone Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery and unoperated matched controls ingesting a liquid mixed meal (n = 9-10 in each group), and 3) individuals with previous RYGB compared with unoperated controls ingesting isocaloric glucose, fat, or protein (n = 6 in each group). Plasma was collected after an overnight fast and up to 6 h after ingestion (≥12 time points). In cohort 1, fasting GDF15 concentrations were ∼480 pg/mL. Concentrations after sucrose or isomaltose intake did not differ from baseline (P = 0.26 to P > 0.99) and total area under the curves (tAUCs were similar between groups (P = 0.77). In cohort 2, fasting GDF15 concentrations were as follows (pg/mL): RYGB = 540 ± 41.4, SG = 477 ± 36.4, and controls = 590 ± 41.8, with no between-group differences (P = 0.73). Concentrations did not increase at any postprandial time point (over all time factor: P = 0.10) and tAUCs were similar between groups (P = 0.73). In cohort 3, fasting plasma GDF15 was similar among the groups (P > 0.99) and neither glucose, fat, nor protein intake consistently increased the concentrations. In conclusion, we find that plasma GDF15 was not stimulated by meal intake and that fasting concentrations did not differ between RYGB-, SG-, and body mass index (BMI)-matched controls when investigated during the weight stable phase after RYGB and SG.NEW & NOTEWORTHY Our combined data show that GDF15 does not increase in response to a liquid meal. Moreover, we show for the first time that ingestion of sucrose, isomaltose, glucose, fat, or protein also does not increase plasma GDF15 concentrations, questioning the role of GDF15 in regulation of food source preference. Finally, we find that neither fasting nor postprandial plasma GDF15 concentrations are increased in individuals with previous bariatric surgery compared with unoperated body mass index (BMI)-matched controls.

Circulating Growth Differentiation Factor 15 Is Increased Preceding Preeclampsia Diagnosis: Implications as a Disease Biomarker

Background

We investigated the biomarker potential of growth differentiation factor 15 (GDF‐15), a stress response protein highly expressed in placenta, to predict preeclampsia.

Methods and Results

In 2 prospective cohorts (cohort 1: 960 controls, 39 women who developed preeclampsia; cohort 2: 950 controls, 41 developed preeclampsia), plasma concentrations of GDF‐15 at 36 weeks' gestation were significantly increased among those who developed preeclampsia (P<0.001), area under the receiver operating characteristic curves (AUC) of 0.66 and 0.71, respectively. In cohort 2 a ratio of sFlt‐1/PlGF (a clinical biomarker for preeclampsia) had a sensitivity of 61.0% at 83.2% specificity to predict those who will develop preeclampsia (AUC of 0.79). A ratio of GDF‐15×sFlt‐1/PlGF yielded a sensitivity of 68.3% at 83.2% specificity (AUC of 0.82). GDF‐15 was consistently elevated across a number of international cohorts: levels were higher in placenta and blood from women delivering <34 weeks' gestation due to preterm preeclampsia in Melbourne, Australia; and in the blood at 26 to 32 weeks' gestation among 57 women attending the Manchester Antenatal Vascular Service (MAViS, UK) who developed preeclampsia (P=0.0002), compared with 176 controls. In the Preeclampsia Obstetric adVerse Events biobank (PROVE, South Africa), plasma GDF‐15 was significantly increased in women with preeclampsia with severe features (P=0.02; n=14) compared to controls (n=14).

Conclusions

We conclude circulating GDF‐15 is elevated among women more likely to develop preeclampsia or diagnosed with the condition. It may have value as a clinical biomarker, including the potential to improve the sensitivity of sFlt‐1/PlGF ratio.

Fragile X-Related Protein 1 (FXR1) Promotes Trophoblast Migration at Early Pregnancy via Downregulation of GDF-15 Expression

Fragile X-related protein 1 (FXR1) is an RNA-binding protein that can regulate specific mRNA decay in cells. Our previous study showed that FXR1 expression was significantly decreased in trophoblasts from patients with unexplained recurrent spontaneous abortion (RSA); however, the role of FXR1 in trophoblast function during early placenta development has not been fully elucidated. In this study, we found that knockdown of FXR1 using siRNA effectively inhibited the migration of HTR-8 cells and extravillous trophoblast (EVT) outgrowth in an ex vivo extravillous explant culture model. Furthermore, through analysis of a panel of cytokines, we found that the GDF-15 protein was upregulated after knockdown of FXR1 in HTR-8/SVneo cells. This was further confirmed by western blotting and immunofluorescence in HTR-8/SVneo cells and an extravillous explant. Our data also showed that FXR1 expression was downregulated and GDF-15 was upregulated in chorionic villous tissues from RSA patients compared with those from healthy controls (HCs). Further, immunohistochemistry showed a strong expression of GDF-15 in chorionic villous tissue in the RSA group, which was mainly distributed in villous trophoblasts (CTBs) and syncytiotrophoblasts (STBs). Moreover, knockdown of GDF-15 enhanced the migration of HTR-8 cells, while overexpression of GDF-15 using plasmid or treatment with recombinant human GDF-15 protein inhibited trophoblast migration. Importantly, RNA-binding protein immunoprecipitation showed that FXR1 directly bound to the 3'-UTR of GDF-15 mRNA to promote GDF-15 mRNA decay. Together, our data provide new insight into the function of FXR1 in human placenta via regulation of GDF-15 expression in trophoblasts and suggest a possible pathological process involved in RSA.

A study of serum growth differentiation factor 15 in Indian women with and without gestational diabetes mellitus in the third trimester of pregnancy and its association with pro-inflammatory markers and glucose metabolism

The pathogenesis of gestational diabetes mellitus (GDM) is multifactorial and it shares many features with type 2 diabetes mellitus. Growth differentiation factor 15 (GDF-15), a member of transforming growth factor-β superfamily, is expressed in a high amount in the placenta in addition to other organs. This cross-sectional study was performed to assess the difference of GDF-15 and pro-inflammatory cytokines between pregnant women with or without GDM, and to explore the possible association of GDF-15 with the parameters of dysglycemia (Serum insulin, HOMA-IR, fasting, 60 min, and 120 min post-75 gm oral glucose plasma glucose levels) and inflammation (IL-6 and TNF-α) in women with GDM at 24-28 weeks of gestation. Thirty-five women with GDM and 30 age-matched non-diabetic pregnant control (NDPC) subjects were recruited for the study. Mean serum GDF-15, IL-6, and TNF-α levels were significantly higher in GDM in comparison to the NDPC population. These differences persisted even after adjusting for the possible confounders like maternal age and BMI. GDF-15 level showed a positive correlation with parameters of dysglycemia (Serum insulin, HOMA-IR, fasting, 60 min, and 120 min post-75 gm oral glucose plasma glucose levels) but a variable correlation with the markers of inflammation. In conclusion, our study provides evidence that, in Indian women, serum GDF-15 level is higher in GDM in comparison to age-matched pregnant subjects without GDM in the early third trimester pregnancy. Moreover, in third trimester, GDF-15 level increases with increase in plasma glucose and insulin resistance.

Roles of TGF-β Superfamily Proteins in Extravillous Trophoblast Invasion

Following embryo implantation, extravillous trophoblasts (EVTs) invade the maternal decidua to a certain extent during early pregnancy, which is critical for normal placentation and successful pregnancy in humans. Although sharing a similar protein structure, the transforming growth factor-β (TGF-β) superfamily members exert divergent functions in regulating EVT invasion, which contributes to a relative balance of TGF-β superfamily proteins in precisely modulating this process at the maternal-fetal interface during the first trimester of pregnancy. This review details recent advances in our understanding of the functions of TGF-β superfamily members and their corresponding receptors, signaling pathways, and downstream molecular targets in regulating human EVT invasion from studies using various in vitro or ex vivo experimental models. Also, the relevance of these discoveries about TGF-β superfamily members to adverse pregnancy outcomes is summarized. The application of 3D culture trophoblast organoids, single-cell sequencing, and microfluidic assays in EVT invasion studies will help better reveal the molecular mechanisms through which TGF-β superfamily members regulate human EVT invasion, shedding light on the development of innovative strategies for predicting, diagnosing, treating, and preventing adverse human pregnancy outcomes related to EVT invasion dysfunction.

Serum growth differentiation factor 15 is closely associated with metabolic abnormalities in Chinese pregnant women

Aims

To explore the relationship between serum growth differentiation factor 15 (GDF15) and metabolic abnormalities in Chinese pregnant women.

Materials and Methods

We recruited 200 patients with gestational diabetes mellitus (GDM) and 211 matched normal control within 24–28 weeks of pregnancy. Enzyme‐linked immunosorbent assay (ELISA) was used to determine the serum GDF15 levels of all participants. Then we grouped participants according to the number of metabolic abnormalities (including blood glucose, blood lipids and blood pressure), divided them into a normal metabolic group, one metabolic abnormality group, two or more metabolic abnormalities group. Finally, multinomial logistic regression analysis was used to estimate the odds radio (OR) and 95% CIs expressing the association between GDF15 and metabolic abnormalities in pregnant women.

Results

Through bivariate correlation analysis, we found that serum GDF15 is linearly correlated with glucose metabolism indices, such as 1h‐PG, 2h‐PG, HbA1c (all P < 0.05). In addition, serum GDF15 and triglycerides were linearly correlated (P < 0.05). Grouping by the number of metabolic abnormalities, we found that as GDF15 levels increased, the risk of metabolic abnormalities also increased (OR > 1), and the risk of multiple metabolic abnormalities was higher. As the number of metabolic abnormalities increased, serum GDF15 levels also were elevated (P < 0.001).

Conclusions

The results suggest that serum GDF15 levels are closely associated with metabolic abnormalities in pregnant women and may be used as a predictor of metabolic abnormalities during pregnancy.

Synergistic action of estradiol and PGE2 on endometrial transcriptome in vivo resembles pregnancy effects better than estradiol alone†

Successful pregnancy establishment in mammals depends on numerous interactions between embryos and the maternal organism. Estradiol-17β (E2) is the primary embryonic signal in the pig, and its importance has been questioned recently. However, E2 is not the only molecule of embryonic origin. In pigs, prostaglandin E2 (PGE2) is abundantly synthesized and secreted by conceptuses and endometrium. The present study aimed to determine the role of PGE2 and its simultaneous action with E2 in changes in porcine endometrial transcriptome during pregnancy establishment. The effects of PGE2 and PGE2 acting with E2 were studied using an in vivo model of intrauterine hormone infusions, and were compared to the effects of E2 alone and conceptuses' presence on day 12 of pregnancy. The endometrial transcriptome was profiled using gene expression microarrays followed by statistical analyses. Downstream analyses were performed using bioinformatics tools. Differential expression of selected genes was verified by quantitative polymerase chain reaction. Microarray analysis revealed 2413 differentially expressed genes (DEGs) in the endometrium treated simultaneously with PGE2 and E2 (P < 0.01). No significant effect of PGE2 administered alone on endometrial transcriptome was detected. Gene ontology annotations enriched for DEGs were related to multiple processes such as: focal adhesion, vascularization, cell migration and proliferation, glucose metabolism, tissue remodeling, and activation of immune response. Simultaneous administration of E2 and PGE2 induced more changes within endometrial transcriptome characteristic to pregnancy than infusion of E2 alone. The present findings suggest that synergistic action of estradiol-17β and PGE2 resembles the effects of pregnancy on endometrial transcriptome better than E2 alone.

Role of Growth Differentiation Factor 15 in Lung Disease and Senescence: Potential Role Across the Lifespan

Growth Differentiation Factor 15 (GDF15) is a divergent member of transforming growth factor-beta (TGF-β) superfamily and is ubiquitously expressed, under normal physiological conditions. GDF15 expression increases during many pathological states and serves a marker of cellular stress. GDF15 has multiple and even paradoxical roles within a pathological condition, as its effects can be dose- and time-dependent and vary based on the targeted tissues and downstream pathways. GDF15 has emerged as one of the most recognized proteins as part of the senescence associated secretory phenotype. Cellular senescence plays a major role in many lung diseases across the life-span from bronchopulmonary dysplasia in the premature neonate to COPD and idiopathic pulmonary fibrosis in aged adults. GDF15 levels have been reported to be as a useful biomarker in chronic obstructive pulmonary disease, lung fibrosis and pulmonary arterial hypertension and predict disease severity, decline in lung function and mortality. Glial-cell-line-derived neurotrophic factor family receptor alpha-like (GFRAL) in the brain stem has been identified as the only validated GDF15 receptor and mediates GDF15-mediated anorexia and wasting. The mechanisms and pathways by which GDF15 exerts its pulmonary effects are being elucidated. GDF15 may also have an impact on the lung based on the changes in circulating levels or through the central action of GDF15 activating peripheral metabolic changes. This review focuses on the role of GDF15 in different lung diseases across the lifespan and its role in cellular senescence.

Second- and third-trimester serum levels of growth-differentiation factor-15 in prediction of pre-eclampsia

OBJECTIVE

Pre-eclampsia (PE) is a significant contributor to adverse maternal and perinatal outcome; however, accurate prediction and early diagnosis of this condition remain a challenge. The aim of this study was to compare serum levels of growth-differentiation factor-15 (GDF-15) at three different gestational ages between asymptomatic women who subsequently developed preterm or term PE and healthy controls.

METHODS

This was a case-control study drawn from a prospective observational study on adverse pregnancy outcomes in women attending for their routine second- and third-trimester hospital visits. Serum GDF-15 was determined in 300 samples using a commercial GDF-15 enzyme-linked immunosorbent assay: 120 samples at 19-24 weeks of gestation, 120 samples at 30-34 weeks and 60 samples at 35-37 weeks. Multiple linear regression was applied to logarithmically transformed GDF-15 control values to evaluate the influence of gestational age at blood sampling and maternal characteristics on GDF-15 results. GDF-15 multiples of the normal median (MoM) values, adjusted for gestational age and maternal characteristics, were compared between pregnancies that subsequently developed preterm or term PE and healthy controls.

RESULTS

Values of GDF-15 increased with gestational age. There were no significant differences in GDF-15 MoM values between cases of preterm or term PE and normotensive pregnancies at 19-24 or 35-37 weeks of gestation. At 30-34 weeks, GDF-15 MoM values were significantly increased in cases of preterm PE, but not in those who later developed term PE. Elevated GDF-15 MoM values were associated significantly with a shorter interval between sampling at 30-34 weeks and delivery with PE (P = 0.005).

CONCLUSION

Serum GDF-15 levels at 19-24 or 35-37 weeks of gestation are not predictive of preterm or term PE. At 30-34 weeks, GDF-15 levels are higher in women who subsequently develop preterm PE; however, this difference is small and GDF-15 is unlikely to be useful in clinical practice when used in isolation. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The GDF15-GFRAL Pathway in Health and Metabolic Disease: Friend or Foe?

GDF15 is a cell activation and stress response cytokine of the glial cell line-derived neurotrophic factor family within the TGF-β superfamily. It acts through a recently identified orphan member of the GFRα family called GFRAL and signals through the Ret coreceptor. Cell stress and disease lead to elevated GDF15 serum levels, causing anorexia, weight loss, and alterations to metabolism, largely by actions on regions of the hindbrain. These changes restore homeostasis and, in the case of obesity, cause a reduction in adiposity. In some diseases, such as advanced cancer, serum GDF15 levels can rise by as much as 10-100-fold, leading to an anorexia-cachexia syndrome, which is often fatal. This review discusses how GDF15 regulates appetite and metabolism, the role it plays in resistance to obesity, and how this impacts diseases such as diabetes, nonalcoholic fatty liver disease, and anorexia-cachexia syndrome. It also discusses potential therapeutic applications of targeting the GDF15-GFRAL pathway and lastly suggests some potential unifying hypotheses for its biological role.

GDF15, an update of the physiological and pathological roles it plays: a review

Growth differentiation factor 15 (GDF15) is a peptide hormone, and a divergent member of the transforming growth factor beta (TGFβ) superfamily. In normal physiology, GDF15 is expressed in multiple tissues at a low concentration. GDF15 is overexpressed during and following many pathological conditions such as tissue injury and inflammation in order to play a protective role. However, GDF15 appears to promote tumour growth in the later stages of malignant cancer. The recently identified endogenous receptor for GDF15, GDNF family receptor a-like (GFRAL), has allowed elucidation of a physiological pathway in which GDF15 regulates energy homeostasis and body weight, primarily via appetite suppression. The anorectic effect of GDF15 provides some therapeutic potential in management of cancer-related anorexia/cachexia and obesity. Despite the identification of GFRAL as a GDF15 receptor, there appears to be other signalling mechanisms utilized by GDF15 that further increase the possibility of development of therapeutic treatments, should these pathways be fully characterized. In this review, GDF15 function in both physiological and pathological conditions in various tissues will be discussed.

Estradiol-17β-Induced Changes in the Porcine Endometrial Transcriptome In Vivo

Estradiol-17β (E2) is a key hormone regulating reproductive functions in females. In pigs, E2, as the main conceptus signal, initiates processes resulting in prolonged corpus luteum function, embryo development, and implantation. During early pregnancy the endometrium undergoes morphological and physiological transitions that are tightly related to transcriptome changes. Recently, however, the importance of E2 as a primary conceptus signal in the pig has been questionable. Thus, the aim of the present study was to determine the effects of E2 on the porcine endometrial transcriptome in vivo and to compare these effects with transcriptome profiles on day 12 of pregnancy. Microarray analysis revealed differentially expressed genes (DEGs) in response to E2 with overrepresented functional terms related to secretive functions, extracellular vesicles, cell adhesion, proliferation and differentiation, tissue rearrangements, immune response, lipid metabolism, and many others. Numerous common DEGs and processes for the endometrium on day 12 of pregnancy and E2-treated endometrium were identified. In summary, the present study is the first evidence for the effect of E2 on transcriptome profiles in porcine endometrium in vivo in the period corresponding to the maternal recognition of pregnancy. The presented results provide a valuable resource for further targeted studies considering genes and pathways regulated by conceptus-derived estrogens and their role in pregnancy establishment.

Serum growth differentiation factor 15 is associated with glucose metabolism in the third trimester in Chinese pregnant women

OBJECTIVE

Growth differentiation factor 15 (GDF15) has been demonstrated to increase in diabetes as a protective factor. However, studies assessing relationships between GDF15 levels and gestational diabetes mellitus (GDM) are limited. In this study, we aimed to investigate whether GDF15 levels are related to GDM in Chinese subjects.

METHODS

We included 200 GDM patients and 200 matched normal controls in the second trimester as well as 130 GDM patients and 130 matched normal controls in the third trimester. Serum GDF15 levels of all participants were determined using an enzyme-linked immunosorbent assay (ELISA). Then, according to GDF15 levels, we equally divided the participants in the second and third trimesters into four subgroups respectively. The relationships of serum GDF15 levels with glucolipid metabolism indicators were analyzed.

RESULTS

In the third trimester, GDF15 levels were significantly higher in the GDM patients than in the normal controls (P < 0.001). Additionally, fasting blood glucose (FBG), 1-h postprandial glucose (1h-PG), 2-h postprandial glucose (2h-PG), hemoglobin A1C (HbA1c) and area under curve of glucose (AUCG) from the 75-g oral glucose tolerance test (OGTT) were positively associated with GDF15 levels (P < 0.05), even after adjusting for age, pregestational BMI, changes of BMI until the third trimester, gestational age, twin and family history of diabetes. Moreover, GDF15 levels were higher in the third trimester than in the second trimester (P < 0.001). No significant relationships were found between GDF15 levels and glucolipid metabolism in the second trimester (P > 0.05).

CONCLUSIONS

Serum GDF15 levels were positively correlated with glucose metabolism in the third trimester in Chinese pregnant women.

Nausea and vomiting of pregnancy and hyperemesis gravidarum

Nausea and vomiting of pregnancy (NVP) is a common condition that affects as many as 70% of pregnant women. Although no consensus definition is available for hyperemesis gravidarum (HG), it is typically viewed as the severe form of NVP and has been reported to occur in 0.3-10.8% of pregnant women. HG can be associated with poor maternal, fetal and child outcomes. The majority of women with NVP can be managed with dietary and lifestyle changes, but more than one-third of patients experience clinically relevant symptoms that may require fluid and vitamin supplementation and/or antiemetic therapy such as, for example, combined doxylamine/pyridoxine, which is not teratogenic and may be effective in treating NVP. Ondansetron is commonly used to treat HG, but studies are urgently needed to determine whether it is safer and more effective than using first-line antiemetics. Thiamine (vitamin B1) should be introduced following protocols to prevent refeeding syndrome and Wernicke encephalopathy. Recent advances in the genetic study of NVP and HG suggest a placental component to the aetiology by implicating common variants in genes encoding placental proteins (namely GDF15 and IGFBP7) and hormone receptors (namely GFRAL and PGR). New studies on aetiology, diagnosis, management and treatment are under way. In the next decade, progress in these areas may improve maternal quality of life and limit the adverse outcomes associated with HG.

Plasma FGF-21 and GDF-15 are elevated in different inherited metabolic diseases and are not diagnostic for mitochondrial disorders

Recently, the plasma cytokines FGF-21 and GDF-15 were described as cellular metabolic regulators. They share an endocrine function and are highly expressed in the liver under stress and during starvation. Several studies found that these markers have high sensitivity and specificity for the diagnosis of mitochondrial diseases, especially those with prominent muscular involvement. In our study, we aimed to determine whether these markers could help distinguish mitochondrial diseases from other groups of inherited diseases. We measured plasma FGF-21 and GDF-15 concentrations in 122 patients with genetically confirmed primary mitochondrial disease and 127 patients with non-mitochondrial inherited diseases. Although GDF-15 showed better analytical characteristics (sensitivity = 0.66, specificity = 0.64, area under the curve [AUC] = 0.88) compared to FGF-21 (sensitivity = 0.51, specificity = 0.76, AUC = 0.78) in the pediatric group of mitochondrial diseases, both markers were also elevated in a variety of non-mitochondrial diseases, especially those with liver involvement (Gaucher disease, galactosemia, glycogenosis types 1a, 1b, 9), organic acidurias and some leukodystrophies. Thus, the overall positive and negative predictive values were not acceptable for these measurements to be used as diagnostic tests for mitochondrial diseases (FGF-21 positive predictive value [PPV] = 34%, negative predictive value [NPV] = 73%; GDF-15 PPV = 47%, NPV = 28%). We suggest that FGF-21 and GDF-15 increase in patients with metabolic diseases with metabolic or oxidative stress and inflammation.

GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans

GDF15 is an established biomarker of cellular stress. The fact that it signals via a specific hindbrain receptor, GFRAL, and that mice lacking GDF15 manifest diet-induced obesity suggest that GDF15 may play a physiological role in energy balance. We performed experiments in humans, mice, and cells to determine if and how nutritional perturbations modify GDF15 expression. Circulating GDF15 levels manifest very modest changes in response to moderate caloric surpluses or deficits in mice or humans, differentiating it from classical intestinally derived satiety hormones and leptin. However, GDF15 levels do increase following sustained high-fat feeding or dietary amino acid imbalance in mice. We demonstrate that GDF15 expression is regulated by the integrated stress response and is induced in selected tissues in mice in these settings. Finally, we show that pharmacological GDF15 administration to mice can trigger conditioned taste aversion, suggesting that GDF15 may induce an aversive response to nutritional stress.

Analysis of GDF15 and IGFBP7 in Hyperemesis Gravidarum Support Causality

Objective Hyperemesis gravidarum, severe nausea and vomiting in pregnancy, occurs in up to 2% of pregnancies and leads to significant weight loss, dehydration, electrolyte imbalance, and ketonuria. It is associated with both maternal and fetal morbidity. Familial aggregation studies and twin studies suggest a genetic component. In a recent GWAS, we showed that placentation, appetite, and cachexia genes GDF15 and IGFBP7 are linked to hyperemesis gravidarum (HG). The purpose of this study is to determine whether GDF15 and IGFBP7 are upregulated in HG patients.

Methods We compared serum levels of GDF15 and IGFBP7 at 12 and 24 weeksʼ gestation in women hospitalized for HG, and two control groups, women with nausea and vomiting of pregnancy (NVP), and women with no NVP.

Results We show GDF15 and IGFBP7 serum levels are significantly increased in women with HG at 12 weeksʼ gestation. Serum levels of hCG are not significantly different between cases and controls. At 24 weeks gestation, when symptoms have largely resolved, there is no difference in GDF15 and IGFBP7 serum levels between cases and controls.

Conclusion This study supports GDF15 and IGFBP7 in the pathogenesis of HG and may be useful for prediction and diagnosis. The GDF15-GFRAL brainstem-activated pathway was recently identified and therapies to treat conditions of abnormal appetite are under intense investigation. Based on our findings, HG should be included.

Evidence GDF15 Plays a Role in Familial and Recurrent Hyperemesis Gravidarum

Introduction Hyperemesis gravidarum (HG), a pregnancy complication characterized by severe nausea and vomiting in pregnancy, occurs in up to 2% of pregnancies. It is associated with both maternal and fetal morbidity. HG is highly heritable and recurs in approximately 80% of women. In a recent genome-wide association study, it was shown that placentation, appetite, and the cachexia gene GDF15 are linked to HG. The purpose of this study was to explore whether GDF15 alleles linked to overexpression of GDF15 protein segregate with the condition in families, and whether the GDF15 risk allele is associated with recurrence of HG.

Methods We analyzed GDF15 overexpression alleles for segregation with disease using exome-sequencing data from 5 HG families. We compared the allele frequency of the GDF15 risk allele, rs16982345, in patients who had recurrence of HG with its frequency in those who did not have recurrence.

Results Single nucleotide polymorphisms (SNPs) linked to higher levels of GDF15 segregated with disease in HG families. The GDF15 risk allele, rs16982345, was associated with an 8-fold higher risk of recurrence of HG.

Conclusion The findings of this study support the hypothesis that GDF15 is involved in the pathogenesis of both familial and recurrent cases of HG. The findings may be applicable when counseling women with a familial history of HG or recurrent HG. The GDF15-GFRAL brainstem-activated pathway was recently identified and therapies to treat conditions of abnormal appetite are under development. Based on our findings, patients carrying GDF15 variants associated with GDF15 overexpression should be included in future studies of GDF15-GFRAL-based therapeutics. If safe, this approach could reduce maternal and fetal morbidity.

Placenta and appetite genes GDF15 and IGFBP7 are associated with hyperemesis gravidarum

Hyperemesis gravidarum (HG), severe nausea and vomiting of pregnancy, occurs in 0.3-2% of pregnancies and is associated with maternal and fetal morbidity. The cause of HG remains unknown, but familial aggregation and results of twin studies suggest that understanding the genetic contribution is essential for comprehending the disease etiology. Here, we conduct a genome-wide association study (GWAS) for binary (HG) and ordinal (severity of nausea and vomiting) phenotypes of pregnancy complications. Two loci, chr19p13.11 and chr4q12, are genome-wide significant (p < 5 × 10-8) in both association scans and are replicated in an independent cohort. The genes implicated at these two loci are GDF15 and IGFBP7 respectively, both known to be involved in placentation, appetite, and cachexia. While proving the casual roles of GDF15 and IGFBP7 in nausea and vomiting of pregnancy requires further study, this GWAS provides insights into the genetic risk factors contributing to the disease.

Effect of proline rich 15-deficiency on trophoblast viability and survival

Deviations from the normal program of gene expression during early pregnancy can lead to early embryonic loss as well as dysfunctional placentation, which can cause significant morbidity and mortality. Proline rich 15 (PRR15) is a low molecular weight nuclear protein expressed by the trophoblast during early gestation. Lentivirus-mediated knockdown of PRR15 mRNA in ovine trophectoderm led to demise of the embryo by gestational day 15, providing compelling evidence that PRR15 expression is critical during this precarious window of development. Our objective was to determine the effect of PRR15 knockdown on trophoblast gene expression, proliferation, and survival. The first-trimester human trophoblast cell line, ACH-3P, was infected with control lentivirus or a lentivirus expressing a short hairpin (sh)RNA to target PRR15 mRNA for degradation, resulting in a 68% reduction in PRR15 mRNA. Microarray analysis of these cell lines revealed differential expression of genes related to cancer, focal adhesion, and p53 signaling. These changes included significant up-regulation of GDF15, a cytokine increased in pregnancies with preeclampsia. Viability and proliferation decreased in PRR15-deficient cells, which was consistent with down-regulation of cell cycle-related genes CCND1 and CDK6 and an up-regulation of CCNG2 and CDKN1A in the PRR15-deficient cells. TNFSF10, a tumor necrosis factor superfamily member known to induce apoptosis increased significantly in the PRR15-deficient cells. Migration through a basement membrane matrix decreased and an increased population of apoptotic cells was present when treated with shRNA to target PRR15. These results suggest that PRR15 enhances trophoblast viability and survival during early implantation and placentation.

The nuclear receptor REV-ERBα represses the transcription of growth/differentiation factor 10 and 15 genes in rat endometrium stromal cells

Cellular oscillators in the uterus play critical roles in the gestation processes of mammals through entraining of the clock proteins to numerous downstream genes, including growth/differentiation factor (Gdf)10 and Gdf15. The expression of Gdf10 and Gdf15 is significantly increased in the uterus during decidualization, but the mechanism underlying the regulation of Gdf gene expression in the uterus is poorly understood. Here, we focused on the function of the cellular oscillators in the expression of Gdf family by using uterine endometrial stromal cells (UESCs) isolated from pregnant Per2‐dLuc transgenic rats. A significant decline of Per2‐dLuc bioluminescence activity was induced in in vitro decidualized UESCs, and concomitantly the expression of canonical clock genes was downregulated. Conversely, the expression of Gdf10 and Gdf15 of the Gdf was upregulated. In UESCs transfected with Bmal1‐specific siRNA, in which Rev‐erbα expression was downregulated, Gdf10 and Gdf15 were upregulated. However, Gdf5, Gdf7, and Gdf11 were not significantly affected by Bmal1 silencing. The expression of Gdf10 and Gdf15 was enhanced after treatment with a REV‐ERBα antagonist in the presence or absence of progesterone. Chromatin immunoprecipitation‐PCR analysis revealed the inhibitory effect of REV‐ERBα on the expression of Gdf10 and Gdf15 in UESCs by recognizing their gene promoters. Collectively, our findings indicate that the attenuation of REV‐ERBα leads to an upregulation of Gdf10 and Gdf15 in decidual cells, in which cellular oscillators are impaired. Our results provide novel evidence regarding the functions of cellular oscillators regulating the expression of downstream genes during the differentiation of UESCs.

Elevated growth differentiation factor 15 expression predicts poor prognosis in epithelial ovarian cancer patients

The purpose of this study was to determine the expression of growth differentiation factor 15 (GDF15) and explore its clinical significance in epithelial ovarian cancer (EOC) patients. The expression of GDF15 in EOC tissues and serum samples was evaluated using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. The association of GDF15 expression with clinicopathologic parameters was analyzed. Survival time was assessed using the Kaplan-Meier technique and Cox regression model. Both in EOC tissues and serum, high GDF15 levels were obviously related with advanced International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, ascites, and chemoresistance. Kaplan-Meier analysis indicated that EOC patients with high GDF15 expression showed poorer progression-free survival (PFS) and overall survival (OS). Multivariate analysis demonstrated that GDF15 expression was an independent predictor of PFS in EOC patients. Our study shows that elevated GDF15 expression was associated with poor prognosis in EOC patients. We suggest that GDF15 is a novel biomarker for the early detection of EOC, prediction of the response to chemotherapy, and screening for recurrence in EOC patients.

Anorexia-cachexia and obesity treatment may be two sides of the same coin: role of the TGF-b superfamily cytokine MIC-1/GDF15

Anorexia-cachexia associated with cancer and other diseases is a common and often fatal condition representing a large area of unmet medical need. It occurs most commonly in advanced cancer and is probably a consequence of molecules released by tumour cells, or tumour-associated interstitial or immune cells. These may then act directly on muscle to cause atrophy and/or may cause anorexia, which then leads to loss of both fat and lean mass. Although the aetiological triggers for this syndrome are not well characterized, recent data suggest that MIC-1/GDF15, a transforming growth factor-beta superfamily cytokine produced in large amounts by cancer cells and as a part of other disease processes, may be an important trigger. This cytokine acts on feeding centres in the hypothalamus and brainstem to cause anorexia leading to loss of lean and fat mass and eventually cachexia. In animal studies, the circulating concentrations of MIC-1/GDF15 required to cause this syndrome are similar to those seen in patients with advanced cancer, and at least some epidemiological studies support an association between MIC-1/GDF15 serum levels and measures of nutrition. This article will discuss its mechanisms of central appetite regulation, and the available data linking this action to anorexia-cachexia syndromes that suggest it is a potential target for therapy of cancer anorexia-cachexia and conversely may also be useful for the treatment of severe obesity.

The Expression of GDF-15 in the Human Vitreous in the Presence of Retinal Pathologies with an Inflammatory Component

PURPOSE

The presence of growth differentiation factor-15 (GDF-15), a protein implicated in the regulation of the inflammatory response, was investigated in the vitreous of patients with vitreoretinal disorders.

METHODS

Vitreous and plasma samples were collected from patients with idiopathic epiretinal membrane (IERM), macular hole (MH), rhegmatogenous retinal detachment (RRD), nucleus drop (ND), or proliferative diabetic retinopathy (PDR). GDF-15 concentrations were measured using ELISA.

RESULTS

The vitreous levels of GDF-15 were higher in ND (5) and PDR (14) patients (1494 ± 243 and 904 ± 138 pg/mL, respectively) than RRD (3), MH (3), and IERM (8) patients (302 ± 160, 288 ± 24, and 254 ± 91 pg/mL, respectively). The vitreous levels of GDF-15 were significantly higher in patients with inflammatory vitreoretinal disorders (p < 0.0001).

CONCLUSIONS

This is the first report showing that GDF-15 appears to be expressed in the vitreous, and that its expression is significantly higher in the presence of a vitreoretinal disorder in which there is an inflammatory component.

A bioplex analysis of cytokines and chemokines in first trimester maternal plasma to screen for predictors of miscarriage

Background

We have previously shown in two independent cohorts that circulating first trimester Macrophage Inhibitory Cytokine-1 (MIC-1) levels are lower in women in early pregnancy who are destined to miscarriage. While promising, the diagnostic performance of measuring MIC-1 alone was not sufficient for it to be a useful predictive test for miscarriage. Besides MIC-1, there are other cytokines, as well as chemokines, involved in facilitating early pregnancy. We reasoned that screening these factors in maternal plasma could uncover other predictive markers of miscarriage.

Methods

This was a nested case control study, of 78 women from a prospective study of 462 attending the Early Pregnancy Assessment Unit in the first trimester (EPAU) with a threatened miscarriage; 34 of these subsequently miscarried (cases) and 44 went on to have a normal delivery (controls) Cytokines IL-1β, IL-6 and IL-10, and the chemokines, CXCL8, CCL2, CCL5, CCL7 and CX3CL1 were measured in plasma from our cohort.

Results

The cytokines IL-1β, IL-6, IL-10 and the chemokine CXCL8 were not detectable in first trimester plasma. The chemokines CCL2, CCL5, CCL7 and CX3CL1 were detectable in all samples but levels did not vary across 5–12 weeks of gestation among controls. Plasma levels of these chemokines were no different in the miscarriage cohort compared to controls.

Conclusion

The chemokines CCL2, CCL5, CCL7 and CX3CL1 were detectable in plasma during the first trimester while IL-1β, IL-6, IL-10 and CXCL8 were not. However, none of the cytokines and chemokines screened were different in maternal plasma in cases or controls. These therefore do not appear to have potential for application as predictive biomarkers of miscarriage.

Serum growth differentiation factor 15 levels in newly diagnosed multiple myeloma patients

BACKGROUND/AIMS

Multiple myeloma (MM) is a hematological cancer associated with increased clonal malignant plasma cells. Growth differentiation factor 15 (GDF 15) is a protein that is highly expressed in the bone marrow mesenchymal stem cells of patients with MM. This study investigated whether the clinical stage of the disease, treatment response and survival are affected by pretreatment serum GDF 15 levels.

METHODS

Serum GDF 15 levels were measured in 35 newly diagnosed MM patients and 27 healthy controls. The correlation between serum GDF 15 levels and various clinical and laboratory parameters was analyzed.

RESULTS

The study demonstrated significantly higher levels of GDF 15 in MM patients. There was a negative correlation between GDF 15 levels, hemoglobin and albumin levels, and a positive correlation between GDF 15 levels, CRP, creatinine, β-2-microglobulin and stage. GDF 15 levels were lower in patients who could receive autologous stem cell transplantation compared to other groups, representing a statistically significant difference. However, in the survival analyses, GDF 15 level did not have an impact on survival.

CONCLUSION

High serum levels of GDF 15 may indicate a poor treatment response. Our study supports the prognostic value of GDF 15 in MM.

Plasma MIC-1 and PAPP-a levels are decreased among women presenting to an early pregnancy assessment unit, have fetal viability confirmed but later miscarry

Background

We have recently shown first trimester Macrophage inhibitory cytokine-1 (MIC-1) and Pregnancy Associated Plasma Protein-A (PAPP-A) serum concentrations are depressed among asymptomatic women destined to miscarry. Here we examined whether plasma levels of MIC-1 and PAPP-A are depressed among women presenting to an Early Pregnancy Assessment Unit (EPAU), noted to have a confirmed viable fetus, but subsequently miscarry.

Methods

We performed a prospective cohort study, recruiting 462 women in the first trimester presenting to EPAU and had fetal viability confirmed by ultrasound. We obtained plasma samples on the same day and measured MIC-1, PAPP-A and human chorionic gonadotrophin (hCG), grouping the cohort according to whether they later miscarried or not. To correct for changes in analyte levels across gestation, we expressed the data as Multiples of the normal Median (MoMs).

Results

We recruited 462 participants presenting to EPAU at 5-12 weeks gestation. Most (80%) presented with symptoms of threatened miscarriage (e.g. abdominal pain, vaginal bleeding). 34 (7.4%) subsequently miscarried. Median plasma MIC-1 levels among those who miscarried were 50% of those with ongoing pregnancies (Miscarriage cohort MoM 0.50 (25^th-75^th centiles: 0.29-1.33) vs ongoing pregnancies MoM 1.00 (0.65-1.38); p=0.0025). Median plasma PAPP-A MoMs among those who miscarried was 0.57 (0.00-1.12), significantly lower than those with ongoing pregnancies (MoMs 1.00 (0.59-1.59); p=0.036). Plasma hCG levels were also significantly depressed among those who miscarried compared to those with ongoing pregnancies. However, the performance of MIC-1 as a diagnostic marker to predict miscarriage in this cohort was modest, and not improved with the addition of hCG.

Conclusion

MIC-1 and PAPP-A levels are significantly depressed in women presenting to EPAU with ultrasound evidence of fetal viability, but later miscarry. While they are unlikely to be useful as predictive biomarkers in this clinical setting, they probably play important roles in the maintenance of early pregnancy.

Maternal Serum Macrophage Inhibitory Cytokine-1 as a Biomarker for Ectopic Pregnancy in Women with a Pregnancy of Unknown Location

BACKGROUND

Ectopic pregnancy (EP) occurs in 1-2% of pregnancies, but is over-represented as a leading cause of maternal death in early pregnancy. It remains a challenge to diagnose early and accurately. Women often present in early pregnancy with a 'pregnancy of unknown location' (PUL) and the diagnosis and exclusion of EP is difficult due to a lack of reliable biomarkers. A serum biomarker able to clearly distinguish between EP and other pregnancy outcomes would greatly assist clinicians in diagnosing and safely managing PULs. This study evaluates the ability of maternal serum macrophage inhibitory cytokine-1 (MIC-1) levels to differentiate between EP and other pregnancy outcomes in women with a PUL.

METHODS

Sera were collected from 120 women with a PUL at first clinical presentation and assayed for MIC-1 by ELISA. Results were classified according to ultimate pregnancy outcome and the discriminatory ability of MIC-1 to diagnose EP was assessed.

RESULTS

Serum MIC-1 levels were lower in women with histologically confirmed (definite) EP (dEP) (median 552 ng/mL; interquartile range (IQR) 414-693 ng/mL) compared to women with definite viable intra-uterine pregnancies (dVIUPs) (722 ng/mL; IQR 412-1122 ng/mL), and higher when compared to women with definite non-viable intra-uterine pregnancies (dNVIUPs) (465 ng/mL; IQR 341-675 ng/mL). MIC-1 levels were significantly higher in women with dEP compared to women whose PULs resolved without medical intervention (srPUL) (401 ng/mL; IQR 315-475 ng/mL) (p<0.003). There were no women with an ectopic pregnancy where serum MIC-1>1000 ng/mL.

CONCLUSION

Serum MIC-1 levels in PUL were not able to categorically diagnose EP, however, MIC-1 could distinguish women with an EP that required medical intervention and those women whose PULs spontaneously resolved. A single serum MIC-1 measurement also excluded EP at levels above 1000 ng/mL. MIC-1 may play a role in the development of a combined assay of biomarkers for the diagnosis of EP.

Diagnostic accuracy of maternal serum macrophage inhibitory cytokine-1 and pregnancy-associated plasma protein-A at 6-10 weeks of gestation to predict miscarriage

OBJECTIVE

To determine whether serum macrophage inhibitory cytokine-1, pregnancy-associated plasma protein-A (PAPP-A), anandamide, or β-human chorionic gonadotropin (hCG) measured in an asymptomatic population in the middle of the first trimester with a viable fetus predicts subsequent miscarriage.

METHODS

We undertook a prospective cohort study at Mercy Hospital for Women between 2004 and 2008. Participants (N=782) were recruited from prenatal clinics, where samples were taken from asymptomatic women at 6 0/7 to 10 6/7 weeks of gestation. We collected samples from only those women for whom we were able to obtain ultrasound evidence of a singleton with fetal cardiac activity. Serum macrophage inhibitory cytokine-1, PAPP-A, anandamide, and β-hCG concentrations were assayed.

RESULTS

Twenty-one (2.7%) miscarried and 761 did not. Among those who miscarried, macrophage inhibitory cytokine-1 and PAPP-A were significantly decreased at 63% (multiples of the median (MOM) 0.63, 25th-75th percentiles 0.33-0.88) and 23% (MOM 0.23, 25th-75th percentiles 0.12-0.48) of levels seen among those with ongoing pregnancies (P<.001 for both comparisons). In contrast, neither serum β-hCG (MOM 0.99, 25th-75th percentiles 0.46-1.86) nor anandamide (MOM 1.07, 25th-75th percentiles 0.87-1.19) was elevated or decreased among those who miscarried compared with those with ongoing pregnancies. At a fixed 10% false-positive rate (90% specificity), a test combining macrophage inhibitory cytokine-1 and PAPP-A yielded 63% sensitivity and a 6.6 positive likelihood ratio in predicting miscarriage.

CONCLUSION

Low serum levels of macrophage inhibitory cytokine-1 and PAPP-A measured from asymptomatic women at 6-10 weeks of gestation with viable pregnancies can predict subsequent miscarriage. These analytes are likely to have an important biological role in early pregnancy and are likely to be useful clinical biomarkers for miscarriage and other early pregnancy complications.

LEVEL OF EVIDENCE

II.

Growth/differentiation factor-15: prostate cancer suppressor or promoter?

Deregulation of expression and function of cytokines belonging to the transforming growth factor-β (TGF-β) family is often associated with various pathologies. For example, this cytokine family has been considered a promising target for cancer therapy. However, the detailed functions of several cytokines from the TGF-β family that could have a role in cancer progression and therapy remain unclear. One of these molecules is growth/differentiation factor-15 (GDF-15), a divergent member of the TGF-β family. This stress-induced cytokine has been proposed to possess immunomodulatory functions and its high expression is often associated with cancer progression, including prostate cancer (PCa). However, studies clearly demonstrating the mechanisms for signal transduction and functions in cell interaction, cancer progression and therapy are still lacking. New GDF-15 roles have recently been identified for modulating osteoclast differentiation and for therapy for PCa bone metastases. Moreover, GDF-15 is as an abundant cytokine in seminal plasma with immunosuppressive properties. We discuss studies that focus on the regulation of GDF-15 expression and its role in tissue homeostasis, repair and the immune response with an emphasis on the role in PCa development.

MIC-1 (a multifunctional modulator of dendritic cell phenotype and function) is produced by decidual stromal cells and trophoblasts

BACKGROUND

Macrophage inhibitory cytokine-1 (MIC-1) is a multifunctional cytokine produced in high amounts by placental tissue. Inhibiting trophoblast invasion and suppressing inflammation through inhibition of macrophage activation, MIC-1 is thought to provide pleiotropic functions in the establishment and maintenance of pregnancy. So far, little is known about the decidual cell subsets producing MIC-1 and the effect of this cytokine on dendritic cells (DCs), which are known to play a distinct role in the development of pro-fetal tolerance in pregnancy.

METHODS

To identify the decidual cell types expressing and secreting MIC-1, immunohistochemical staining, PCR experiments, western blot analysis and ELISAs were performed. Immature DCs (iDCs) were generated from peripheral blood-derived monocytes and differentiated in the presence of MIC-1 or dexamethasone (Dex) for control. Migratory and proliferative activity of DCs after MIC-1 exposure was investigated by migration and proliferation assay. Cytokine secretion after MIC-1 exposure was tested in isolated uNK cells, isolated CD14+ monocytes, monocyte-derived iDCs and mature DCs. Subsequently, the phenotype of DCs was studied using FACS analysis. To test the T-cell stimulatory capacity of pre-incubated DCs, mixed lymphocyte reaction was applied. Finally, the expression of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) after the exposure of MIC-1 to maturing DCs was analysed by western blot.

RESULTS

Immunohistochemical staining, PCR and western blot experiments demonstrated that MIC-1 is mainly expressed by trophoblast cells and decidual stromal cells. Analysis of the MIC-1 secretion of decidual cell types by ELISA again characterized trophoblast and stromal cells as main producers. The migratory activity of iDCs was significantly induced by MIC-1. No changes in proliferative activity of DCs were observed after MIC-1 pre-incubation. The secretion of pro- or anti-inflammatory cytokines was not affected significantly by MIC-1. Studying the phenotype of DCs after MIC-1 exposure by FACS analysis, we observed that MIC-1 suppresses the expression of typical maturation molecules such as CD25 and CD83 as well as of CD86 during cytokine-induced DC maturation similar to Dex. In addition, T-cell stimulatory capacity of DCs was significantly reduced after MIC-1 exposure. MIC-1 was also able to increase slightly the expression of IDO (a key immunomodulatory enzyme promoting periphereal tolerance) in maturing DCs.

CONCLUSIONS

We have identified MIC-1 as a novel factor (secreted by decidual cells in early pregnancy) that could promote the increase of a tolerogenic subtype of DC in decidua.

The TGF-β superfamily cytokine, MIC-1/GDF15: a pleotrophic cytokine with roles in inflammation, cancer and metabolism

Macrophage inhibitory cytokine-1 (MIC-1/GDF15) is associated with cardiovascular disease, inflammation, body weight regulation and cancer. Its serum levels facilitate the diagnosis and prognosis of cancer and vascular disease. Furthermore, its serum levels are a powerful predictor of all-cause mortality, suggesting a fundamental role in biological processes associated with ageing. In cancer, the data available suggest that MIC-1/GDF15 is antitumorigenic, but this may not always be the case as disease progresses. Cancer promoting effects of MIC-1/GDF15 may be due, in part, to effects on antitumour immunity. This is suggested by the anti-inflammatory and immunosuppressive properties of MIC-1/GDF15 in animal models of atherosclerosis and rheumatoid arthritis. Furthermore, in late-stage cancer, large amounts of MIC-1/GDF15 in the circulation suppress appetite and mediate cancer anorexia/cachexia, which can be reversed by monoclonal antibodies in animals. Available data suggest MIC-1/GDF15 may be an important molecule mediating the interplay between cancer, obesity and chronic inflammation.