Kisspeptin signalling and its correlation with placental ultrastructure and clinical outcomes in pregnant South African women with obesity and gestational diabetes.

INTRODUCTION: Gestational diabetes mellitus (GDM) is a major pregnancy metabolic disorder and is strongly linked with obesity. Kisspeptin is a hormone that increases several thousand-fold in the maternal circulation during human pregnancy, with placenta as its main source. Studies have suggested that kisspeptin regulates trophoblast invasion and promotes pancreatic insulin secretion and peripheral insulin sensitivity. METHODS: In a well-characterized cohort of pregnant South African women and molecular and histological techniques, this study explored the impact and interaction of maternal obesity and GDM on kisspeptin (KISS1) signalling in relation to placental morphology and maternal and neonatal parameters. RESULTS: We found that GDM had no effect on placental KISS1 and KISS1R (KISS1 receptor) mRNA and/or protein expression. However, obesity reduced placental KISS1R mRNA expression even though overall KISS1 protein abundance or localization was not different from the non-obese group. Maternal and cord circulating KISS1 concentrations did not vary with obesity or GDM, but maternal circulating KISS1 was positively correlated with placenta weight in non-GDM obese women, and negatively correlated with placental intervillous space volume in non-GDM non-obese women. Cord serum KISS1 was positively correlated with infant weight in GDM obese women, but negatively correlated with maternal BMI in the non-obese GDM group. Placental syncytiotrophoblast extracellular vesicles exhibited detectable KISS1 and its abundance was ∼50 % lower in those from obese GDM compared to non-GDM women. DISCUSSION: This study shows maternal obesity and GDM can modulate placental kisspeptin signalling and placental morphological development with potential pathophysiological implications for clinically-relevant pregnancy and perinatal outcomes.

Polycystic ovary syndrome and recurrent pregnancy loss, a review of literature.

Objective: PCOS is a syndrome of ovarian dysfunction associated with recurrent pregnancy loss. Several correlating factors have been investigated that influence the risk of pregnancy loss in PCOS. However, uncertainty remains about their contribution to pregnancy loss and prognosis. This review of literature aims to identify what is known and what requires further investigation on the relationship between PCOS and recurrent pregnancy loss, to guide future research and optimize medical guidance throughout pregnancy. Study design: a review of literature was performed on several search engines using the following terms; polycystic ovarian syndrome, PCOS, recurrent pregnancy loss, recurrent miscarriage, RPL, aborted fetus, abortus provocatus, miscarriage and habitual abortion. Results: 37 articles were included; 3 systematic reviews, 1 meta-analysis, 2 randomized controlled trials, 6 prospective cohort studies, 22 case-control studies and 3 case series. The main objectives investigated by studies were pregnancy complications, pregnancy loss and live birth in the PCOS population. Conclusion: Studies that investigated the relationship between PCOS and recurrent pregnancy loss are few and inconsistent and warrant further research. Factors apt for further investigation include the extent to which PCOS phenotypes, BMI, obesity, insulin resistance, hyperandrogenemia, SHBG, hs-CRP, CTRP6, adiponectin, plasma leptin, homocysteine, AMH and thrombophilia contribute to further risk of miscarriage. Other factors requiring further exploration in relation to risk for miscarriage in PCOS patient with RPL include sOB-R, PAI-Fx and the Factor-V-Leiden mutations.

Obesity and gestational diabetes independently and collectively induce specific effects on placental structure, inflammation and endocrine function in a cohort of South African women.

Maternal obesity and gestational diabetes mellitus (GDM) are associated with insulin resistance and health risks for mother and offspring. Obesity is also characterized by low-grade inflammation, which in turn, impacts insulin sensitivity. The placenta secretes inflammatory cytokines and hormones that influence maternal glucose and insulin handling. However, little is known about the effect of maternal obesity, GDM and their interaction, on placental morphology, hormones and inflammatory cytokines. In a South African cohort of non-obese and obese pregnant women with and without GDM, this study examined placental morphology using stereology, placental hormone and cytokine expression using real-time PCR, western blotting and immunohistochemistry, and circulating TNFα and IL-6 concentrations using ELISA. Placental expression of endocrine and growth factor genes was not altered by obesity or GDM. However, LEPTIN gene expression was diminished, syncytiotrophoblast TNFα immunostaining elevated and stromal and fetal vessel IL-6 staining reduced in the placenta of obese women in a manner that was partly influenced by GDM status. Placental TNFα protein abundance and maternal circulating TNFα concentrations were reduced in GDM. Both maternal obesity and, to a lesser extent, GDM were accompanied by specific changes in placental morphometry. Maternal blood pressure and weight gain and infant ponderal index were also modified by obesity and/or GDM. Thus, obesity and GDM have specific impacts on placental morphology and endocrine and inflammatory states that may relate to pregnancy outcomes. These findings may contribute to developing placenta-targeted treatments that improve mother and offspring outcomes, which is particularly relevant given increasing rates of obesity and GDM worldwide. KEY POINTS: Rates of maternal obesity and gestational diabetes (GDM) are increasing worldwide, including in low-middle income countries (LMIC). Despite this, much of the work in the field is conducted in higher-income countries. In a well-characterised cohort of South African women, this study shows that obesity and GDM have specific impacts on placental structure, hormone production and inflammatory profile. Moreover, such placental changes were associated with pregnancy and neonatal outcomes in women who were obese and/or with GDM. The identification of specific changes in the placenta may help in the design of diagnostic and therapeutic approaches to improve pregnancy and neonatal outcomes with particular significant benefit in LMICs.

Kisspeptins and Glucose Homeostasis in Pregnancy: Implications for Gestational Diabetes Mellitus-a Review Article.

Gestational diabetes mellitus (GDM) is becoming an increasingly common complication of pregnancy with the global rise of obesity. The precise pathophysiological mechanisms underpinning GDM are yet to be fully elucidated. Kisspeptin, a peptide encoded by the KISS1 gene, is mainly expressed by placental syncytiotrophoblasts during pregnancy. It is an essential ligand for kisspeptin 1 receptor (KISS1R), which is expressed by both the villous and invasive extravillous cytotrophoblast cells. Circulatory kisspeptins rise dramatically in the second and third trimester of pregnancy coinciding with the period of peak insulin resistance. Kisspeptins stimulate glucose-dependent insulin secretion and decreased plasma levels inversely correlate with markers of insulin resistance. Additionally, kisspeptins play a critical role in the regulation of appetite, energy utilisation and glucose homeostasis. GDM pregnancies have been associated with low circulatory kisspeptins, despite higher placental kisspeptin and KISS1R expression. This review evaluates the role of kisspeptin in insulin secretion, resistance and regulation of appetite as well as its implications in GDM.

Medical conditions associated with recurrent miscarriage-Is BMI the tip of the iceberg?

BACKGROUND: In contrast to sporadic miscarriage, recurrent miscarriage (RM) is a rare entity which affects 1% of couples attempting conception. It is distressing for couples and healthcare professionals as the aetiology is unclear with limited treatment options. Apart from anti-phospholipid syndrome (APS), the strength of associations between RM and commonly investigated endocrine, autoimmune, thrombophilic and uterine structural abnormalities remains uncertain and variable. OBJECTIVES: To assess the prevalence of commonly investigated medical conditions associated with RM. STUDY DESIGN: A 9-year retrospective analysis of a prospectively collected database was conducted for 592 patients seen between 2008 and 2016, in tertiary level RM clinic in South Africa. RESULTS: In this period, 592 patients were assessed. The mean age was 29.73±5.46 (mean±SD), gravidity 4.6±1.82 and parity 0.98±1.05. The mean number of miscarriages per patient was 3.34±1.63, of which two-thirds (61.3%) were in the first trimester, a third (33%) in the second trimester and intrauterine fetal deaths (IUFDs) constituted 6% of total losses. Of the 50% of patients with no identified associated disorders, 15% were unexplained (investigations complete but no associations found), 10% became pregnant during investigation (investigations incomplete) and 25% were lost to follow-up (investigations incomplete). Nearly forty percent (38%) of patients had an associated endocrine disorder (22% PCOS, 11% IGT, 3% Diabetes Mellitus and 2% Thyroid Dysfunction) and 10% a uterine factor (4% Cervical Incompetence, 2% Fibroids, 2% Synechiae and 2% Anomalies). APS and Thrombophilias constituted 3% and 2% of patients respectively. The BMI (mean±SD) amongst patients with Unexplained RM, PCOS and IGT were 28.85±5.95, 30.86±7.79 and 33.40±6.47 respectively. Patients with IGT had significantly higher mean BMI in comparison to those with Unexplained RM (p<0.0001)*** and PCOS (p<0.001)**. CONCLUSION: PCOS, IGT and Type II Diabetes are all likely surrogates for elevated BMI and constitute 70% of those women with RM and identified associated medical disorders. In our population, BMI seems to have a substantial impact on recurrent pregnancy loss and future studies should interrogate its effect on recurrent miscarriage.

Elevated placental expression at the maternal-fetal interface but diminished maternal circulatory kisspeptin in preeclamptic pregnancies.

OBJECTIVE: To investigate the placental mRNA and protein expression of metastasis suppressor gene Kiss-1 and the transcript expression of its receptor GPR-54 across the maternal-fetal interface of healthy and preeclamptic pregnancies. To furthermore compare placental tissue kisspeptin expression to circulatory kisspeptin levels in these pregnancies. SETTING: Secondary and Tertiary Hospital Setting in Cape Town, South Africa. POPULATION: Patients with and without preeclampsia undergoing elective caesarean delivery. METHODS: The placenta, placental bed and decidua parietalis as well as maternal and cord blood in both healthy and preeclamptic pregnancies were simultaneously sampled at elective caesarean delivery. RT-PCR was utilised to determine mRNA expression while immunohistochemistry was employed to investigate protein expression in maternal-fetal tissues. Circulating maternal and cord serum kisspeptin concentrations were determined using ELISA. MAIN OUTCOME MEASURES: Maternal-fetal tissue mRNA expression of Kiss-1 and GPR-54 as well as maternal/cord serum kisspeptin concentrations in healthy and preeclamptic pregnancies. RESULTS: There was high placental kisspeptin expression but low circulating serum kisspeptin levels in pregnancies complicated by preeclampsia. Kiss-1 mRNA and protein expression was minimal in the maternal tissues (placental bed and decidua parietalis) of both healthy and preeclamptic pregnancies. No difference was found in Kiss-1 receptor (GPR-54) mRNA expression across maternal-fetal tissues of healthy and preeclamptic pregnancies. CONCLUSIONS: Increased placental kisspeptin expression is consistent with reduced trophoblast invasiveness and may represent a molecular mechanism that explains the development of preeclampsia. Decreased circulating kisspeptin concentration has the potential to be utilised as a marker for placental dysfunction.

Kisspeptin regulation of genes involved in cell invasion and angiogenesis in first trimester human trophoblast cells.

The precise regulation of extravillous trophoblast invasion of the uterine wall is a key process in successful pregnancies. Kisspeptin (KP) has been shown to inhibit cancer cell metastasis and placental trophoblast cell migration. In this study primary cultures of first trimester human trophoblast cells have been utilized in order to study the regulation of invasion and angiogenesis-related genes by KP. Trophoblast cells were isolated from first trimester placenta and their identity was confirmed by immunostaining for cytokeratin-7. Real-time quantitative RT-PCR demonstrated that primary trophoblast cells express higher levels of GPR54 (KP receptor) and KP mRNA than the trophoblast cell line HTR8Svneo. Furthermore, trophoblast cells also expressed higher GPR54 and KP protein levels. Treating primary trophoblast cells with KP induced ERK1/2 phosphorylation, while co-treating the cells with a KP antagonist almost completely blocked the activation of ERK1/2 and demonstrated that KP through its cognate GPR54 receptor can activate ERK1/2 in trophoblast cells. KP reduced the migratory capability of trophoblast cells in a scratch-migration assay. Real-time quantitative RT-PCR demonstrated that KP treatment reduced the expression of matrix metalloproteinase 1, 2, 3, 7, 9, 10, 14 and VEGF-A, and increased the expression of tissue inhibitors of metalloproteinases 1 and 3. These results suggest that KP can inhibit first trimester trophoblast cells invasion via inhibition of cell migration and down regulation of the metalloproteinase system and VEGF-A.

The differential expression of Kiss1, MMP9 and angiogenic regulators across the feto-maternal interface of healthy human pregnancies: implications for trophoblast invasion and vessel development.

Genes involved in invasion of trophoblast cells and angiogenesis are crucial in determining pregnancy outcome. We therefore studied expression profiles of these genes in both fetal and maternal tissues to enhance our understanding of feto-maternal dialogue. We investigated the expression of genes involved in trophoblast invasion, namely Kiss1, Kiss1 Receptor (Kiss1R) and MMP9 as well as the expression of angiogenic ligands Vascular Endothelial Growth Factor-A (VEGF-A) and Prokineticin-1 (PROK1) and their respective receptors (VEGFR1, VEGFR2 and PROK1R) across the feto-maternal interface of healthy human pregnancies. The placenta, placental bed and decidua parietalis were sampled at elective caesarean delivery. Real-time RT-PCR was used to investigate transcription, while immunohistochemistry and western blot analyses were utilized to study protein expression. We found that the expression of Kiss1 (p<0.001), Kiss1R (p<0.05) and MMP9 (p<0.01) were higher in the placenta compared to the placental bed and decidua parietalis. In contrast, the expression of VEGF-A was highest in the placental bed (p<0.001). While VEGFR1 expression was highest in the placenta (p<0.01), the expression of VEGFR2 was highest in the placental bed (p<0.001). Lastly, both PROK1 (p<0.001) and its receptor PROK1R (p<0.001) had highest expression in the placenta. Genes associated with trophoblast invasion were highly expressed in the placenta which could suggest that the influence on invasion capacity may largely be exercised at the fetal level. Furthermore, our findings on angiogenic gene expression profiles suggest that angiogenesis may be regulated by two distinct pathways with the PROK1/PROK1R system specifically mediating angiogenesis in the fetus and VEGFA/VEGFR2 ligand-receptor pair predominantly mediating maternal angiogenesis.