The Role of Kisspeptin in the Pathogenesis of Pregnancy Complications: A Narrative Review

Pregnancy, delivery, and neonatal outcomes among women with PCOS and endometriosis: a population database cohort

PURPOSE

PCOS and endometriosis are independent risk factors for perinatal outcomes. Little research has evaluated the concomitant effects of these conditions, nor have studies been conducted on a population database. We sought to identify the pregnancy, delivery, and neonatal outcomes in women with polycystic ovary syndrome (PCOS) and endometriosis vs. PCOS without endometriosis.

METHODS

A retrospective population-based cohort study was performed extracting data using ICD-9 codes from the HCUP-NIS Database from 2004 to 2014. Endometriosis in women with PCOS represented the study group (n = 163), and the remaining PCOS, non-endometriosis patients constituted the reference group (n = 14,719). Subjects were included once per delivery. Demographics were compared using chi-squared tests. Confounding effects in pregnancy outcomes were controlled using binary logistic regression analysis.

RESULTS

Concomitant endometriosis and PCOS patients were more likely to be white (88.5% vs.71.0%, p < 0.001), with BMI < 30 kg/m2 (87.1% vs.77.8%, p < 0.004) and from lower income quartiles (27.1% vs.17.1%, p < 0.017) when compared to PCOS without endometriosis. Comparing pregnancy complication rates, placental abruption (p < 0.018, aOR 3.01, 95% CI 1.21-7.50), Cesarean section (p < 0.003, aOR 1.75, 95% CI 1.21-2.53), deep venous thromboses (p < 0.002, aOR 74.31, 95% CI 4.57-1209.21), and venous thromboembolic events (p < 0.031, aOR 10.40, 95% CI 1.24-87.37), were increased in the study group compared to the reference group.

CONCLUSION

Women with PCOS and endometriosis were more likely to be white, of lower socioeconomic status, lean, and experience abruptio-placenta, cesarean deliveries, and venous thromboembolisms. Since little was previously known about the combined outcomes of PCOS and endometriosis, it is difficult to counsel patients on risks. Our findings can help clinicians manage pregnant PCOS patients with endometriosis to minimize complications such as abruptio placenta and VTE.

The kisspeptin system in and beyond reproduction: exploring intricate pathways and potential links between endometriosis and polycystic ovary syndrome

Endometriosis and polycystic ovary syndrome (PCOS) are two common female reproductive disorders with a significant impact on the health and quality of life of women affected. A novel hypothesis by evolutionary biologists suggested that these two diseases are inversely related to one another, representing a pair of diametrical diseases in terms of opposite alterations in reproductive physiological processes but also contrasting phenotypic traits. However, to fully explain the phenotypic features observed in women with these conditions, we need to establish a potential nexus system between the reproductive system and general biological functions. The recent discovery of kisspeptin as pivotal mediator of internal and external inputs on the hypothalamic-pituitary-gonadal axis has led to a new understanding of the neuroendocrine upstream regulation of the human reproductive system. In this review, we summarize the current knowledge on the physiological roles of kisspeptin in human reproduction, as well as its involvement in complex biological functions such as metabolism, inflammation and pain sensitivity. Importantly, these functions are known to be dysregulated in both PCOS and endometriosis. Within the evolving scientific field of "kisspeptinology", we critically discuss the clinical relevance of these discoveries and their potential translational applications in endometriosis and PCOS. By exploring the possibilities of manipulating this complex signaling system, we aim to pave the way for novel targeted therapies in these reproductive diseases.

Placental mRNA Expression of Neurokinin B Is Increased in PCOS Pregnancies with Female Offspring

Current research suggests that polycystic ovary syndrome (PCOS) might originate in utero and implicates the placenta in its pathogenesis. Kisspeptin (KISS1) and neurokinin B (NKB) are produced by the placenta in high amounts, and they have been implicated in several pregnancy complications associated with placental dysfunction. However, their placental expression has not been studied in PCOS. We isolated mRNA after delivery from the placentae of 31 PCOS and 37 control women with term, uncomplicated, singleton pregnancies. The expression of KISS1, NKB, and neurokinin receptors 1, 2, and 3 was analyzed with real-time polymerase chain reaction, using β-actin as the reference gene. Maternal serum and umbilical cord levels of total testosterone, sex hormone-binding globulin (SHBG), free androgen index (FAI), androstenedione, dehydroepiandrosterone sulfate (DHEAS), Anti-Mullerian hormone (AMH), and estradiol were also assessed. NKB placental mRNA expression was higher in PCOS women versus controls in pregnancies with female offspring. NKB expression depended on fetal gender, being higher in pregnancies with male fetuses, regardless of PCOS. NKB was positively correlated with umbilical cord FAI and AMH, and KISS1 was positively correlated with cord testosterone and FAI; there was also a strong positive correlation between NKB and KISS1 expression. Women with PCOS had higher serum AMH and FAI and lower SHBG than controls. Our findings indicate that NKB might be involved in the PCOS-related placental dysfunction and warrant further investigation. Studies assessing the placental expression of NKB should take fetal gender into consideration.

Kisspeptin: a potential therapeutic target in patients with unexplained infertility?

BACKGROUND

Kisspeptin has recently emerged as a key regulator of the reproductive axis in women. Kisspeptin, acting centrally via the kisspeptin receptor, stimulates the secretion of the gonadotrophin-releasing hormone (GnRH).

AIMS

To investigate serum kisspeptin levels in infertility patients for its clinical utilisation in management and understanding of the pathophysiology of infertility in a wide array of patients.

METHODS

This prospective case-control study analysis involved 92 primary infertile women with PCOS, diminished ovarian reserve (DOR), unexplained infertility (UEI), and male factor infertility between 20 and 42 years of age. Serum samples were collected between the second and fifth day of the menstrual cycle. The kisspeptin level was determined using a human kisspeptin ELISA kit according to the manufacturer's procedure.

RESULTS

The median value of serum kisspeptin in the PCOS infertility group was significantly higher than that in the UEI group (p = 0.011). There was a statistically significant (p = 0.015, r =  -0.182) negative weak correlation found between serum kisspeptin levels and age. The optimal cutoff value obtained to differentiate the UEI from others (PCOS infertility + DOR + male factor infertility) according to the serum kisspeptin level was 214.3 ng/L with a sensitivity of 55% and specificity of 80.9%.

CONCLUSIONS

Understanding the role of kisspeptin may lead to its use as a biomarker in infertility diagnosis in UEI patients and might guide the use of kisspeptin analogues in selected patients for infertility management.

Epigenetics of Hypogonadotropic Hypogonadism: Molecular Mimicry between Severe Acute Respiratory Syndrome Coronavirus 2 and KISSR

This study analyzed KISS1 and its receptor KISSR for peptide sharing with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was found that SARS-CoV-2 shares numerous minimal immune pentapeptide determinants with KISSR only. The peptide sharing has a high immunologic potential since almost all the common peptides are present in 101 SARS-CoV-2-derived immunoreactive epitopes. Data are in favor of configuring molecular mimicry as an epigenetic factor that can alter KISSR thus causing the hypogonadotropic hypogonadism syndrome with which altered KISSR associates.

Role of kisspeptin in decidualization and unexplained recurrent spontaneous abortion via the ERK1/2 signalling pathway

INTRODUCTION

This study aimed to study the expression and function of kisspeptin during human uterine decidualization in recurrent spontaneous abortion (RSA) and the underlying mechanism.

METHODS

All patients were recruited from the Clinical Reproductive Center of the Second Affiliated Hospital of Soochow University. Mice models of RSA (CBA/J × DBA/2) and normal pregnancy (CBA/J × BALB/c) were established, respectively. Kisspeptin expression in the serum and decidual tissues of women with RSA were detected. The function of kisspeptin during decidualization in human endometrial stromal cells (HESCs) was assessed by enhancing and silencing kisspeptin expression. CBA/J × DBA/2 pregnant mice were injected with kisspeptin polypeptide, kisspeptin receptor blocker, and expression of decidualization markers was observed. The regulation of ERK1/2 signalling pathway were verified.

RESULTS

Serum kisspeptin levels were significantly lower in patients with RSA than in normal pregnant individuals, as was the expression of kisspeptin, p-ERK, and decidualization indicators in the decidua. Additionally, kisspeptin inhibition downregulated the expression of decidualization markers in HESCs. In mice with RSA, kisspeptin was significantly downregulated, and p-ERK expression at the maternal-foetal interface was significantly decreased. Moreover, exogenous kisspeptin supplementation improved the levels of IGFBP-1 and dPRL, upregulated p-ERK expression, and reduced the abortion rate.

DISCUSSION

Kisspeptin is involved in promoting uterine decidualization via the ERK1/2 signalling pathway.