Ectopic pregnancy is associated with high anandamide levels and aberrant expression of FAAH and CB1 in fallopian tubes

Association of cannabis use with female infertility based on NHANES

BACKGROUND

With the gradual legalisation of recreational cannabis, associated health effects have received widespread attention, but their association with female infertility remains unclear. The aim of this study was to explore the association between cannabis use and infertility among females of childbearing age in the United States.

METHODS

Data were obtained from the National Health and Nutrition Examination Survey 2013-2018; 1694 female participants aged 18-45 years were included. The association between cannabis use and female infertility was analysed by logistic regression analysis. All data were weighted before analysis.

RESULTS

After adjusting for all covariates, former cannabis users demonstrated significantly elevated odds of infertility compared with never-users (odds ratio: 2.04, 95% confidence interval: 1.21-3.43, P = 0.012), whereas current cannabis users exhibited no significant difference in infertility odds relative to never-users. In subgroup analysis, former users aged 18-35 years exhibited higher odds of infertility than never-users (odds ratio: 2.37, 95% confidence interval: 1.11-5.04, P = 0.027); but former cannabis users aged 36-45 years demonstrated no significant difference in infertility odds compared with never-users. Among former cannabis users aged 18-35 years, those with sustained abstinence exceeding 3 years demonstrated significantly elevated odds of infertility compared with never-users (odds ratio: 2.94, 95% confidence interval: 1.29-6.71, P = 0.005). In contrast, individuals with shorter abstinence durations (<3 years) showed no significant difference in infertility odds relative to never-users.

CONCLUSIONS

Among females of childbearing age, the odds of infertility was not elevated among current cannabis users compared with never-users, while the odds of infertility was elevated among former users. This relationship between cannabis use and female fertility is more often reflected in the distant term (>3 years of cessation), and this adverse association is more pronounced among females in the most active reproductive years (18-35).

The Role of the Endocannabinoid System in Human Gametogenesis

The endocannabinoid system (ECS) is a complex endocrine network involved in maintaining body homeostasis. It comprises endocannabinoids, their receptors (CB1 and CB2), and the enzymes and transporters responsible for their synthesis and degradation. While the ECS's role in the nervous system is well established, its functions in other organs and peripheral tissues, including the cardiovascular, gastrointestinal, and reproductive systems, remain incompletely understood. With the increasing use of marijuana, particularly among individuals of reproductive age, concerns have emerged regarding its potential impact on male and female fertility. Phytocannabinoids (∆9tethrahydrocannabinol and cannabidiol), as well as synthetic cannabimimetic drugs, interact with the ECS, influencing sperm and oocyte physiology and reproductive outcomes. Recent research has identified ECS-related biomarkers with potential applications in infertility diagnosis, particularly in assessing male fertility with greater precision. Furthermore, emerging evidence suggests that ECS signaling pathways are involved in epigenetic modifications, which may influence health maintenance, disease susceptibility, and transgenerational inheritance patterns. These findings highlight the therapeutic potential of ECS modulation in reproductive disorders and broader medical applications. This narrative review aims to elucidate the role of the ECS in human reproduction, with a particular focus on the influence of endocannabinoids on gametogenesis. While current research underscores the critical role of the ECS in fertility, further investigations are needed to fully elucidate its underlying mechanisms and its broader implications for reproductive health and therapeutic interventions.

Cell-free pregnancy-associated microRNAs in blood plasma as potential biomarker in early diagnosis of ectopic pregnancy

PURPOSE

Ectopic pregnancy (EP) is one of the life-threatening disorders in early pregnancy and current strategies are inadequate in its clinical management. There is a need to identify more accurate biomarkers for early diagnosis of ectopic pregnancy.

METHODS

This case-control study was conducted in a group of 35 women diagnosed with ectopic pregnancy and 31 women with a normal singleton pregnancy. Patients' characteristics including the level of β-hCG, age, body mass index (BMI), and gestational age have been recorded. The plasma levels of cell-free hsa-miR-411, hsa-miR-433, and hsa-miR-524 were examined by qRT-PCR using specific primers.

RESULTS

There was no statistically significant difference in maternal age, gestational age, and BMI between the two groups. β-hCG concentrations in EP were significantly lower than normal pregnancy group. Cell-free hsa-miR-411 and hsa-miR-433 had statistically significant differences in concentrations in women with EP and normal pregnancy. hsa-miR-411 and hsa-miR-433 had better diagnostic values for discriminating EP from normal pregnancy. Moreover, hsa-miR-411 and hsa-miR-433 showed a specificity of 61% and 53%, and a sensitivity of 72% and 79%, respectively.

CONCLUSIONS

hsa-miR-411 and hsa-miR-433 microRNAs concentrations in plasma have potential as a predicting biomarker for early diagnosis of EP. However, further research is needed before using miRNAs in clinical practice for both diagnostic and therapeutic goals.

Untargeted Metabolomic Biomarker Discovery for the Detection of Ectopic Pregnancy

Ectopic pregnancy (EP) is the leading cause of maternal morbidity and mortality in the first trimester. Using an untargeted metabolomic approach, we sought to identify putative plasma biomarkers using tandem liquid chromatography-mass spectrometry for the detection of tubal EP. This case-control study included the prospective recruitment of 50 tubal EP cases and 50 early intrauterine pregnancy controls. To avoid over-fitting, logistic regression models were developed in a randomly selected discovery group (30 cases vs. 30 controls) and validated in the test group (20 cases vs. 20 controls). In total, 585 mass spectral features were detected, of which 221 molecular features were significantly altered in EP plasma (p < 0.05). Molecular networking and metabolite identification was employed using the Global Natural Products Social Molecular Networking (GNPS) database, which identified 97 metabolites at a high confidence level. Top significant metabolites include subclasses of sphingolipids, carnitines, glycerophosphocholines, and tryptophan metabolism. The top regression model, consisting of D-erythro-sphingosine and oleoyl-carnitine, was validated in a test group and achieved an area under receiving operating curve (AUC) (95% CI) = 0.962 (0.910-1) with a sensitivity of 100% and specificity of 95.9%. Metabolite alterations indicate alterations related to inflammation and abnormal placentation in EP. The validation of these metabolite biomarkers in the future could potentially result in improved early diagnosis.

Lactate plasma level as a potential biomarker in early diagnosis of ectopic pregnancy: A case-control survey

Introduction

A novel metabolomics survey proposed lactic acid as a diagnostic biomarker to detect ectopic pregnancy (EP). Here we investigate the plasma level of lactate for early diagnosis of EP as a potential biomarker.

Methods

In a case-control study, the reproductive aged women with definite tubal EP (6-10 weeks' gestation), referred to our department during 2021-2022, considered as case group, and women with normal singleton pregnancy in the same gestational age as control group. After informed concept, demographic data (maternal and gestational age and parity) recorded and 5 mL venous blood samples were taken to detect the lactate plasma level. The data analyzed using SPSS software ver22.

Results

Finally, 95 participations (50 in case and 45 in control group) enrolled. The clinical results showed that the most of case group were aged more than 35 years old with had higher parity and body mass index, but, no statistically significant difference showed up. On the other hand, although the lactate level was slightly higher in women with EP, but, the plasma lactate level did not statistically differ between the two study groups. Also, the logistic regression showed no relationship between the demographic variables and the lactate plasma level.

Conclusion

It seems that the plasma level of lactate cannot be a diagnostic biomarker for EP.

Potential biomarkers to predict return to fertility after discontinuation of female contraceptives-looking to the future

Nowadays there are multiple types of contraceptive methods, from reversible to permanent, for those choosing to delay pregnancy. Misconceptions about contraception and infertility are a key factor for discontinuation or the uptake of family planning methods. Regaining fertility (the ability to conceive) after contraceptive discontinuation is therefore pivotal. Technical studies to date have evaluated return to fertility by assessing pregnancy as an outcome, with variable results, or return to ovulation as a surrogate measure by assessing hormone levels (such as progesterone, LH, FSH) with or without transvaginal ultrasound. In general, relying on time to pregnancy as an indicator of return to fertility following contraceptive method discontinuation can be problematic due to variable factors independent of contraceptive effects on fertility, hormone clearance, and fertility recovery. Since the ability to conceive after contraceptive method discontinuation is a critical factor influencing product uptake, it is important to have robust biomarkers that easily and accurately predict the timing of fertility return following contraception and isolate that recovery from extrinsic and circumstantial factors. The main aim of this review is to summarize the current approaches, existing knowledge, and gaps in methods of evaluating return-to-fertility as well as to provide insights into the potential of new biomarkers to more accurately predict fertility restoration after contraceptive discontinuation. Biomarker candidates proposed in this document include those associated with folliculogenesis, cumulus cell expansion, follicular rupture and ovulation, and endometrial transport and receptivity which have been selected and scored on predefined criteria meant to evaluate their probable viability for advancement. The review also describes limitations, regulatory requirements, and a potential path to clinically testing these selected biomarkers. It is important to understand fertility restoration after contraceptive method discontinuation to provide users and health providers with accurate evidence-based information. Predictive biomarkers, if easy and low-cost, have the potential to enable robust evaluation of RTF, and provide potential users the information they desire when selecting a contraceptive method. This could lead to expanded uptake and continuation of modern contraception and inform the development of new contraceptive methods to widen user's family planning choices.

Endocannabinoid System Components of the Female Mouse Reproductive Tract Are Modulated during Reproductive Aging

The endocannabinoid (eCB) system has gained ground as a key modulator of several female fertility-related processes, under physiological/pathological conditions. Nevertheless, its modulation during reproductive aging remains unclear. This study aimed to investigate the expression levels of the main receptors (cannabinoid receptor 1,CB₁; cannabinoid receptor 2, CB₂; G-protein coupled receptor, GPR55; and transient receptor potential vanilloid type 1 channel, TRPV1) and metabolic enzymes (N-acylphosphatidylethanolamine phospholipase D, NAPE-PLD; fatty acid amide hydrolase, FAAH; monoacylglycerol lipase, MAGL; and diacylglycerol lipase, DAGL-α and -β) of this system in the ovaries, oviducts, and uteri of mice at prepubertal, adult, late reproductive, and post-reproductive stages through quantitative ELISA and immunohistochemistry. The ELISA showed that among the receptors, TRPV1 had the highest expression and significantly increased during aging. Among the enzymes, NAPE-PLD, FAAH, and DAGL-β were the most expressed in these organs at all ages, and increased age-dependently. Immunohistochemistry revealed that, regardless of age, NAPE-PLD and FAAH were mainly found in the epithelial cells facing the lumen of the oviduct and uteri. Moreover, in ovaries, NAPE-PLD was predominant in the granulosa cells, while FAAH was sparse in the stromal compartment. Of note, the age-dependent increase in TRPV1 and DAGL-β could be indicative of increased inflammation, while that of NAPE-PLD and FAAH could suggest the need to tightly control the levels of the eCB anandamide at late reproductive age. These findings offer new insights into the role of the eCB system in female reproduction, with potential for therapeutic exploitation.

Emerging Roles of Endocannabinoids as Key Lipid Mediators for a Successful Pregnancy

In recent years, Cannabis use/misuse for treating pregnancy-related symptoms and other chronic conditions has increased among pregnant women, favored by decriminalization and/or legalization of its recreational uses in addition to its easy accessibility. However, there is evidence that prenatal Cannabis exposure might have adverse consequences on pregnancy progression and a deleterious impact on proper neurodevelopmental trajectories in the offspring. Maternal Cannabis use could interfere with the complex and finely controlled role performed by the endocannabinoid system in reproductive physiology, impairing multiple gestational processes from blastocyst implantation to parturition, with long-lasting intergenerational effects. In this review, we discuss current clinical and preclinical evidence regarding the role of endocannabinoids in development, function, and immunity of the maternal–fetal interface, focusing on the impact of Cannabis constituents on each of these gestational processes. We also discuss the intrinsic limitations of the available studies and the future perspectives in this challenging research field.

Serine Hydrolases in Lipid Homeostasis of the Placenta-Targets for Placental Function?

The metabolic state of pregnant women and their unborn children changes throughout pregnancy and adapts to the specific needs of each gestational week. These adaptions are accomplished by the actions of enzymes, which regulate the occurrence of their endogenous substrates and products in all three compartments: mother, placenta and the unborn. These enzymes determine bioactive lipid signaling, supply, and storage through the generation or degradation of lipids and fatty acids, respectively. This review focuses on the role of lipid-metabolizing serine hydrolases during normal pregnancy and in pregnancy-associated pathologies, such as preeclampsia, gestational diabetes mellitus, or preterm birth. The biochemical properties of each class of lipid hydrolases are presented, with special emphasis on their role in placental function or dysfunction. While, during a normal pregnancy, an appropriate tonus of bioactive lipids prevails, dysregulation and aberrant signaling occur in diseased states. A better understanding of the dynamics of serine hydrolases across gestation and their involvement in placental lipid homeostasis under physiological and pathophysiological conditions will help to identify new targets for placental function in the future.

Nitric oxide positively affects endometrial receptivity via FAAH and NAPE-PLD in vitro

Objective

To determine if models of human 'receptive' and 'non-receptive endometrium' differ in their responses to nitric oxide (NO) supplementation by measuring the levels of the enzymes of the endocannabinoid system (ECS) (fatty acid amide hydrolase (FAAH) and N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD)), which control the 'anandamide tone' essential for successful pregnancy.

Design

A study of FAAH and NAPE-PLD expression (using human endometrium) through the menstrual cycle and an in vitro using a model of 'receptive' (Ishikawa) and 'non-receptive' (HEC-1A) human endometrial cell lines treated with the NO-donating compound S-nitroso-N-acetylpenicillamine (SNAP).

Results

Immunoreactivity measured by optimised H-score for both FAAH and NAPE-PLD was reduced in secretory (receptive) endometrium compared to proliferative (non-receptive) endometrium (P = 0.0009 and <0.0001, respectively). FAAH and NAPE transcript levels were significantly higher in untreated Ishikawa cells than in HEC-1A cells (P = 0.0228 and 0.0001, respectively). Treatment of cultures with SNAP resulted in an increase in the amount of FAAH mRNA produced by Ishikawa cells and a decrease in NAPE-PLD mRNA. No effect of SNAP was observed in HEC-1A cells. Similarly, FAAH protein was significantly decreased in endometria representative of the receptive endometrium.

Conclusion

These data suggest that NO most likely affects the expression of ECS enzymes in the implantation site of a receptive endometrium; a phenomenon not seen in a non-receptive endometrium. These effects are most marked with FAAH expression, suggesting that FAAH may play the more critical role in ensuring the correct 'anandamide tone' for successful embryo implantation than NAPE-PLD.

Lay summary

Embryo implantation into the wall of the uterus is only successful when the inner wall of the uterus (the endometrium) is 'receptive', because if it is 'non-receptive', implantation will fail. Previous work showed that enzymes of the 'endocannabinoid system' are critical for implantation by maintaining the correct level of a fat called anandamide. This is by balancing its synthesis (by N-acylphosphatidylethanolamine specific phospholipase D, NAPE-PLD) and degradation (by fatty acid amide hydrolase, FAAH). Using immortalised cell lines as models of 'receptive' and 'non-receptive' human endometrium, we demonstrate a key stimulator of implantation, nitric oxide, has a positive effect on implantation by both increasing the mRNA levels of the degrading enzyme (FAAH) and decreasing the expression of the synthesising enzyme (NAPE-PLD). These effects are most marked with the degrading enzyme, suggesting that FAAH plays a more critical role than NAPE-PLD in ensuring the correct 'anandamide tone' for successful embryo implantation.

The Cannabinoid Delta-9-tetrahydrocannabinol Disrupts Estrogen Signaling in Human Placenta

Cannabis consumption is increasing worldwide either for recreational or medical purposes. Its use during gestation is associated with negative pregnancy outcomes such as, intrauterine growth restriction, preterm birth, low birth weight, and increased risk of miscarriage, though the underlying molecular mechanisms are unknown. Cannabis sativa main psychoactive compound, Δ9-tetrahydrocannabinol (THC) is highly lipophilic, and as such, readily crosses the placenta. Consequently, THC may alter normal placental development and function. Here, we hypothesize alterations of placental steroidogenesis caused by THC exposure. The impact on placental estrogenic signaling was examined by studying THC effects upon the enzyme involved in estrogens production, aromatase and on estrogen receptor α (ERα), using placental explants, and the cytotrophoblast cell model BeWo. Aromatase expression was upregulated by THC, being this effect potentiated by estradiol. THC also increased ERα expression. Actions on aromatase were ERα-mediated, as were abolished by the selective ER downregulator ICI-182780 and dependent on the cannabinoid receptor CB1 activation. Furthermore, the presence of the aromatase inhibitor Exemestane did not affect THC-induced increase in ERα expression. However, THC effects on ERα levels were reversed by the antagonists of CB1 and CB2 receptors AM281 and AM630, respectively. Thus, we demonstrate major alterations in estrogen signaling caused by THC, providing new insight on how cannabis consumption leads to negative pregnancy outcomes, likely through placental endocrine alterations. Data presented in this study, together with our recently reported evidence on THC disruption of placental endocannabinoid homeostasis, represent a step forward into a deeper comprehension of the puzzling actions of THC.

Cannabinoid receptor type-1 and its correlation with CB1 gene polymorphism-1359G/A in ectopic pregnancy compared to the control group

AIM

Ectopic pregnancy (EP) is one of the most important causes of maternal mortality. This study aimed to evaluate the immunohistochemical (IHC) expression of the cannabinoid receptor type-1 (CB1) and its association with CB1-1359G/A gene polymorphism (rs1049353) in the fallopian tubes in EP compared to controls.

METHODS

In this case-control study, 100 women with EP (cases) and 100 women that underwent abdominal surgery due to the hysterectomy or uterine tubal ligation (healthy controls) were included. Genotyping of CB1-1359G/A polymorphism, tissue expression of CB1 at the protein and mRNA levels were studied using restriction fragment length polymorphism, IHC method, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

Genotyping showed that in EP, the frequency of AA, AA+AG genotypes, and A allele was significantly higher than healthy control subjects (p = 0.001). Also, patients with EP had significantly increased IHC expression of CB-1 compared to the control samples (p = 0.016). Patients with AA and AG genotypes had a significantly higher IHC expression of CB-1 compared to the GG genotype. qRT-PCR analysis showed that patients with EP had significantly increased expression of CB-1 compared to the control samples (p < 0.001). Patients with AA and AG genotypes had higher significant mRNA expression of CB-1 compared to the GG genotype.

CONCLUSIONS

CB1 is likely to be effective in creating innate immunity in humans and can affect the process of EP in the fallopian tube. CB1 is also a pathological valuable factor in identifying the pathway of inflammation during ectopic implantation.

(Endo)Cannabinoids and Gynaecological Cancers

Gynaecological cancers can be primary neoplasms, originating either from the reproductive tract or the products of conception, or secondary neoplasms, representative of metastatic disease. For some of these cancers, the exact causes are unknown; however, it is recognised that the precise aetiopathogeneses for most are multifactorial and include exogenous (such as diet) and endogenous factors (such as genetic predisposition), which mutually interact in a complex manner. One factor that has been recognised to be involved in the pathogenesis and progression of gynaecological cancers is the endocannabinoid system (ECS). The ECS consists of endocannabinoids (bioactive lipids), their receptors, and metabolic enzymes responsible for their synthesis and degradation. In this review, the impact of plant-derived (Cannabis species) cannabinoids and endocannabinoids on gynaecological cancers will be discussed within the context of the complexity of the proteins that bind, transport, and metabolise these compounds in reproductive and other tissues. In particular, the potential of endocannabinoids, their receptors, and metabolic enzymes as biomarkers of specific cancers, such as those of the endometrium, will be addressed. Additionally, the therapeutic potential of targeting selected elements of the ECS as new action points for the development of innovative drugs will be presented.

The fundamental role of the endocannabinoid system in endometrium and placenta: implications in pathophysiological aspects of uterine and pregnancy disorders

BACKGROUND

The endocannabinoid system (ECS) consists of the cannabinoid receptors CB1 and CB2, the main endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and their metabolic enzymes N-acylphosphatidylethanolamine-specific phospholipase D, fatty acid amide hydrolase, diacylglycerol lipase and monoacylglycerol lipase. This system is involved in the modulation of essential physiological processes. Its role in the reproductive system has become significantly important in recent years, given its major role in events such as gametogenesis, decidualisation, implantation and placentation.

OBJECTIVE AND RATIONALE

In this paper, we review the literature and summarize the role of the ECS elements in reproduction and their potential as early markers for diagnosis of reproductive disorders or as pharmacological targets for treatment.

SEARCH METHODS

Original research and review papers published from 1964 to June 2019 were selected in terms of relevance, reliability and quality by searching PubMed, MEDLINE and Web of Science, using the following search terms: endocannabinoid system and endometriosis; endocannabinoid system and ectopic pregnancy; endocannabinoid system and miscarriage; endocannabinoid system and pre-eclampsia; endocannabinoid system and endometrial cancer; endocannabinoid system and reproduction; endocannabinoid, endometrium; placenta; N-acylethanolamines; anandamide; 2-arachidonoylglycerol; and cannabinoids.

OUTCOMES

This review demonstrates relevant information concerning ECS alterations in endometriosis, ectopic pregnancy, miscarriage, pre-eclampsia and endometrial cancer. We highlight the importance of the endocannabinoids in endometrial and placental physiology and pathophysiology, from studies in vitro and in vivo and in clinical observations. The most studied of the endogenous cannabinoids is AEA. The levels of AEA were increased in plasma of patients with endometriosis and miscarriage, as well as in the fallopian tube of women with ectopic pregnancy and in endometrial biopsies of endometrial cancer. Changes in the pattern of expression of the cannabinoid receptor CB1 were also observed in endometrial biopsies of endometriosis, fallopian tube and decidua of patients with ectopic pregnancy and pre-eclamptic placenta. Moreover, alterations in CB2 expression have been reported in association with endometrial cancer. In general, studies on the cannabinoid signalling through CB2 and on the biological activities of the other major endocannabinoid, namely 2-AG, as well as its metabolic enzymes are scarce and avidly required.

WIDER IMPLICATIONS

The pathophysiological mechanisms involved in the described endometrial and placental pathologies are still unclear and lack the means for an early diagnosis. Based on current evidence, though alterations in ECS are demonstrated at tissue level, it is difficult to associate plasmatic changes in AEA with specific endometrial and placental diseases. Thus, pairing alterations in AEA levels with 2-AG and/or other endocannabinoid-like molecules may provide more accurate and early diagnoses. In addition, patients may benefit from new therapies that target the ECS and endocannabinoid signalling.

[Focus on the endocannabinoid system and the reprotoxicity of marijuana in female users]

Among recreative compounds, marijuana is the most used worldwide. Delta9THC binding on brain endocannabinoid receptors drives its psychotropic effects. The endocannabinoid system (ECS) is an endogenous neurohormonal system essential for homeostasis composed of ligands, metabolic enzymes and at least 2 receptors discovered to date. In female reproduction, the ECS regulates the hypothalamic-pituitary axis and many steps of the reproduction process, such as ovulation, tubal transportation and trophoblast implantation. Delta9THC can cross the placental barrier and bind to the fetal endocannabinoid system. In humans, fetal and obstetrical consequences of marijuana use during pregnancy are intrauterine growth restriction and preterm delivery. In the light of legalization projects currently reviewed in several western countries, further research should be conducted to improve knowledge on maternal, fetal and reprotoxic consequences of marijuana use during reproductive age and pregnancy.

Expression and Function of the Endocannabinoid Modulating Enzymes Fatty Acid Amide Hydrolase and N-Acylphosphatidylethanolamine-Specific Phospholipase D in Endometrial Carcinoma

Background: The concentrations of three N-acylethanolamines (NAEs), anandamide (AEA), N-oleoylethanolamide (OEA), and N-palmitylethanolamide (PEA) are increased in the endometria of women with endometrial cancer (EC). It is widely accepted that plasma levels of these three NAEs are regulated by the actions of the rate-limiting enzymes N-acylphoshatidylethanolamine-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), which are synthesizing and degradative, respectively. The expression and activity of these enzymes have not previously been studied in EC.

Methods: FAAH activity in peripheral blood lymphocytes, and transcript and protein expression for FAAH and NAPE-PLD in EC tissues were measured using enzyme, quantitative RT-PCR, and histomorphometry (of immunoreactive tissue sections), respectively. Samples were from 6 post-menopausal women with atrophic endometria (controls) and 34 women with histologically diagnosed EC. Concentrations of the three NAEs also measured in plasma and tissues were correlated with lymphocytic FAAH activity and the NAPE-PLD and FAAH transcript and protein levels.

Results: Peripheral lymphocyte FAAH activity was unaffected in women with EC compared to controls. The FAAH transcript expression level was significantly (p < 0.0001) 75% lower in EC whilst NAPE-PLD levels were not significantly (p = 0.798) increased. In line with the transcript data, a significant (p < 0.0001) tumor type-dependent 70–90% decrease in FAAH protein and significant 4- to 14-fold increase in NAPE-PLD protein (p < 0.0001) was observed in the malignant tissue with more advanced disease having lower FAAH and higher NAPE-PLD expression than less advanced disease. Correlation analyses also confirmed that tissue NAE concentrations were inversely related to FAAH expression and directly correlated to NAPE-PLD expression and the NAPE-PLD/FAAH ratio.

Conclusion: These data support our previous observation of tissue levels of AEA, OEA, and PEA and a role for NAE metabolism in the pathogenesis of EC.

Metabolomic identification of novel diagnostic biomarkers in ectopic pregnancy

INTRODUCTION

Ectopic pregnancy (EP) is a potentially life-threatening condition and early diagnosis still remains a challenge, causing a delay in management leading to tubal rupture.

OBJECTIVES

To identify putative plasma biomarkers for the detection of tubal EP and elucidate altered biochemical pathways in EP compared to intrauterine pregnancies.

METHODS

This case-control study included prospective recruitment of 39 tubal EP cases and 89 early intrauterine pregnancy controls. Plasma samples were biochemically profiled using proton nuclear magnetic resonance spectroscopy (¹H NMR). To avoid over-fitting, datasets were randomly divided into a discovery group (26 cases vs 60 controls) and a test group (13 cases and 29 controls). Logistic regression models were developed in the discovery group and validated in the independent test group. Area under the receiver operating characteristics curve (AUC), 95% confidence interval (CI), sensitivity, and specificity values were calculated.

RESULTS

In total 13 of 43 (30.3%) metabolite concentrations were significantly altered in EP plasma (p < 0.05). Metabolomic profiling yielded significant separation between EP and controls (p < 0.05). Independent validation of a two-metabolite model consisting of lactate and acetate, achieved an AUC (95% CI) = 0.935 (0.843-1.000) with a sensitivity of 92.3% and specificity of 96.6%. The second metabolite model (D-glucose, pyruvate, acetoacetate) performed well with an AUC (95% CI) = 0.822 (0.657-0.988) and a sensitivity of 84.6% and specificity of 86.2%.

CONCLUSION

We report novel metabolomic biomarkers with a high accuracy for the detection of EP. Accurate biomarkers could potentially result in improved early diagnosis of tubal EP cases.

Identification of Novel Predictive Biomarkers for Endometrial Malignancies: N-Acylethanolamines

Objective: To identify new biochemical markers for endometrial cancer (EC). Recent evidence suggests that members of the endocannabinoid system (N-acylethanolamines) that bind to and activate receptors that are dysregulated in EC are involved in this tumour's biology. These observations suggest increased N-acylethanolamine levels in the tissue that might appear in plasma and could be used as disease biomarkers. Methods: N-arachidonoylethanolamine (anandamide, AEA) and the N-acylethanolamine substances, N-oleoylethanolamine (OEA), and N-palmitoylethanolamine (PEA) were quantified in plasma and endometrial tissue collected from 31 EC and seven atrophic controls using UHPLC-MS/MS. Receiver-operating characteristics (ROC) and logistic regression were used to determine diagnostic accuracy. Cannabinoid receptor 1 (CB1) and 2 (CB2) protein levels were determined by specific immunohistochemistry and histomorphometric analyses. Correlations between plasma and tissue levels of the three N-acylethanolamines and tissue levels of the three N-acylethanolamines and CB1 and CB2 receptor expression levels were determined using correlation analysis. Results: Plasma and tissue AEA and PEA levels were significantly (p < 0.05) higher in EC than controls whilst OEA levels were significantly elevated in type 1 EC tissues but not in plasma. There were significant positive correlations between plasma and tissue levels of AEA (R ² = 0.302, p = 0.008) and PEA (R ² = 0.182, p = 0.047), but not for OEA (R ² = 0.022, p = 0.506). The diagnostic accuracies for EC were: sensitivity of 53.3%, specificity of 100% for plasma AEA (>1.36 nM); sensitivity of 73.3%, specificity of 100% for plasma PEA (>27.5 nM); and sensitivity of 93.3%, specificity of 28.6% for plasma OEA (>4.97 nM). Logistic regression increased the area under the ROC curve (AUC) from 0.781 for AEA, 0.857 for PEA, and 0.543 for OEA to a combined AUC of 0.933 for EC diagnosis. Significant inverse correlations between tissue AEA (R ² = 0.343, p = 0.003) and PEA (R ² = 0.384, p < 0.0001) levels and CB1 expression were observed. No correlation between tissue levels of OEA and CB1 and tissue levels of any of the three N-acylethanolamines and CB2 protein expression were observed, except in the type 1 EC patients. Conclusion: Since plasma AEA and PEA are significantly elevated in patients with EC and a reflection of production by the endometrial tumour, then these lipids have the potential to be useful biomarkers for the early diagnosis of EC.

Cannabinoids in Gynecological Diseases

The endocannabinoid system (ECS) is a multifunctional homeostatic system involved in many physiological and pathological conditions. The ligands of the ECS are the endo-cannabinoids, whose actions are mimicked by exogenous cannabinoids, such as phytocannabinoids and synthetic cannabinoids. Responses to the ligands of the ECS are mediated by numerous receptors like the classical cannabinoid receptors (CB₁ and CB₂) as well as ECS-related receptors, e.g., G protein-coupled receptors 18 and 55 (GPR18 and GPR55), transient receptor potential ion channels, and nuclear peroxisome proliferator-activated receptors. The ECS regulates almost all levels of female reproduction, starting with oocyte production through to parturition. Dysregulation of the ECS is associated with the development of gynecological disorders from fertility disorders to cancer. Cannabinoids that act at the ECS as specific agonists or antagonists may potentially influence dysregulation and, therefore, represent new therapeutic options for the therapy of gynecological disorders.

Role of Cannabinoid Receptor Type 1 in Insulin Resistance and Its Biological Implications

Endogenous cannabinoids (ECs) are lipid-signaling molecules that specifically bind to cannabinoid receptor types 1 and 2 (CB1R and CB2R) and are highly expressed in central and many peripheral tissues under pathological conditions. Activation of hepatic CB1R is associated with obesity, insulin resistance, and impaired metabolic function, owing to increased energy intake and storage, impaired glucose and lipid metabolism, and enhanced oxidative stress and inflammatory responses. Additionally, blocking peripheral CB1R improves insulin sensitivity and glucose metabolism and also reduces hepatic steatosis and body weight in obese mice. Thus, targeting EC receptors, especially CB1R, may provide a potential therapeutic strategy against obesity and insulin resistance. There are many CB1R antagonists, including inverse agonists and natural compounds that target CB1R and can reduce body weight, adiposity, and hepatic steatosis, and those that improve insulin sensitivity and reverse leptin resistance. Recently, the use of CB1R antagonists was suspended due to adverse central effects, and this caused a major setback in the development of CB1R antagonists. Recent studies, however, have focused on development of antagonists lacking adverse effects. In this review, we detail the important role of CB1R in hepatic insulin resistance and the possible underlying mechanisms, and the therapeutic potential of CB1R targeting is also discussed.

Mice Missing Cnr1 and Cnr2 Show Implantation Defects

Cannabinoid/endocannabinoid signaling is primarily mediated by cannabinoid receptor type 1 (CB1; encoded by Cnr1) and/or type 2 (CB2; encoded by Cnr2). Here, we show that Cnr1-/-Cnr2-/- mice are subfertile as a result of compromised implantation. Upon implantation, the epithelium is smooth and adhered to the blastocyst trophectoderm within the implantation chamber (crypt) in wild-type mice, whereas the epithelium in Cnr1-/-Cnr2-/- mice is ruffled, which compromises appropriate blastocyst-uterine interactions. The suboptimal implantation leads to higher incidence of pregnancy failure in Cnr1-/-Cnr2-/- mice. Histological analysis revealed heightened edema around the implantation chamber in these deleted females. With the use of a reporter mouse line, we observed that CB2 is present on endothelial cells of uterine blood vessels, and its absence leads to blood vessel leakage during implantation. These results suggest that appropriately regulated uterine edema is important to optimal implantation.

New Insights of Uterine Leiomyoma Pathogenesis: Endocannabinoid System

Background

The aim of this study was to determine if components of the endocannabinoid system are modulated in uterine leiomyomas (fibroids). Components studied included cannabinoid receptors 1 (CB1) and 2 (CB2); the G protein-coupled receptor GPR55; transient potential vanilloid receptor 1 (TRPV1) and the endocannabinoid modulating enzymes N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), and their N-acylethanolamine (NAE) ligands: N-arachidonylethanolamine (AEA), N-oleoylethanolamine (OEA), and N-palmityolethanaolamine (PEA).

Material/Methods

Transcript levels of CB1, CB2, TRPV1, GPR55, NAPE-PLD, and FAAH were measured using RT-PCR and correlated with the tissue levels of the 3 NAEs in myometrial tissues. The tissues studied were: 1) fibroids, 2) myometrium adjacent/juxtaposed to the fibroid lesions, and 3) normal myometrium. Thirty-seven samples were processed for NAE measurements and 28 samples were used for RT-PCR analyses.

Results

FAAH expression was significantly lower in fibroids, resulting in a NAPE-PLD: FAAH ratio that favors higher AEA levels in pre-menopausal tissues, whilst PEA levels were significantly lower, particularly in post-menopausal women, suggesting PEA protects against fibroid pathogenesis. The CB1: CB2 ratio was lower in fibroids, suggesting that loss of CB1 expression affects the fibroid cell phenotype. Significant correlations between reduced FAAH, CB1, and GPR55 expression and PEA in fibroids indicate that the loss of these endocannabinoid system components are biomarkers of leiomyomata.

Conclusions

Loss of expression of CB1, FAAH, GPR55, and PEA production are linked to the pathogenesis of uterine fibroids and further understanding of this might eventually lead to better disease indicators or the development of therapeutic potentials that might eventually be used in the management of uterine fibroids.

Anandamide down-regulates placental transporter expression through CB2 receptor-mediated inhibition of cAMP synthesis

The BCRP/ABCG2 efflux transporter is expressed on the membrane of placental syncytiotrophoblasts and protects the fetus from toxicant exposure. Syncytiotrophoblasts arise from the fusion of cytotrophoblasts, a process negatively regulated by the endocannabinoid, anandamide (AEA). It is unknown whether AEA can influence fetal concentrations of xenobiotics by modulating the expression of transporters in syncytiotrophoblasts. Here, we sought to characterize and identify the mechanism(s) responsible for AEA-mediated down-regulation of the BCRP transporter in human placental explants and BeWo trophoblasts. Treatment of human placental explants with AEA (1 μM, 24 h) reduced hCGα, syncytin-1, and BCRP mRNAs by ˜30%. Similarly, treatment of BeWo trophoblasts with AEA (0-10 μM, 3-24 h) coordinately down-regulated mRNAs for hCGß, syncytin-2, and BCRP. In turn, AEA increased the sensitivity of trophoblasts to the cytotoxicity of mitoxantrone, a known BCRP substrate, and environmental and dietary contaminants including mycoestrogens and perfluorinated chemicals. AEA-treated trophoblasts also demonstrated reduced BCRP transport of the mycoestrogen zearalenone and the diabetes drug glyburide, labeled with BODIPY. The AEA-mediated reduction of BCRP mRNA was abrogated when placental cells were co-treated with AM630, a CB2 receptor inhibitor, or 8-Br-cAMP, a cAMP analog. AEA reduced intracellular cAMP levels in trophoblasts by 75% at 1 h, and completely inhibited forskolin-induced phosphorylation of the cAMP response element binding protein (CREB). AEA also decreased p-CREB binding to the BCRP promoter. Taken together, our data indicate that AEA down-regulates placental transporter expression and activity via CB2-cAMP signaling. This novel mechanism may explain the repression of placental BCRP expression observed during diseases of pregnancy.

Cannabinoid receptor expression in estrogen-dependent and estrogen-independent endometrial cancer

The lack of good diagnostic/prognostic biomarkers and the often late presentation of endometrial cancer (EC) hinders the amelioration of the morbidity and mortality rates associated with this primarily estrogen-driven disease, a disease that is becoming more prevalent in the population. Previous studies on the expression of the classical cannabinoid receptors, CB1 and CB2, suggest these could provide good diagnostic/prognostic biomarkers for EC but those observations have been contradictory. In this study, we sought to resolve the inconsistency of CB1 and CB2 expression levels in different EC studies. To that end, we used qRT-PCR and immunohistochemistry (IHC) for CB1 and CB2 in endometrial biopsies from women with or without EC and found that transcript levels for both CB1 and CB2 were significantly decreased by 90 and 80%, respectively in EC. These observations were supported by histomorphometric studies where CB1 and CB2 staining intensity was decreased in all types of EC. These data suggest that the loss of both types of CB receptors is potentially involved in the development of or progression of EC and that CB1 and CB2 receptor expression could serve as useful histological markers and therapeutic targets in the treatment of or prevention of EC.

MicroRNAs as Potential Serum Biomarkers for Early Detection of Ectopic Pregnancy

Diagnosis of ectopic pregnancy relies on both ultrasound findings and human chorionic gonadotropin (hCG) measurements but due to the need for serial tests, tubal rupture and death represent major maternal and fetal risks. Early detection of ectopic pregnancy is essential and thus a noninvasive diagnostic tool seems crucial for the prevention of adverse effects since studies suggest there is a specific relationship between ectopic pregnancy and increasing microRNA factors. Human fluids in women with ectopic pregnancy reveal a particular change in comparison to healthy women. In addition to certain placental microRNAs circulating through plasma that present a specific concentration and serum profile, microRNAs seem to be possible biomarkers for the detection of pregnancy complications linked to placental pathologies. The aim of this study is to review current literature considering the expression levels of several circulating microRNAs that have shown to be novel potential biomarkers for the diagnosis of tubal ectopic pregnancy.

Spatial distribution of cannabinoid receptor 1 and fatty acid amide hydrolase in the cat ovary and oviduct

Involvement of the endocannabinoid system in female reproduction has been extensively described in humans with the cognate receptors and ligands being found in the ovaries and genital tract. In human, an imbalance of the endocannabinoid system is linked with both ectopic pregnancy and infertility. In bovine species anandamide levels regulate aspects of sperm-oviduct interaction. Here we report the immunohistochemical distribution of cannabinoid receptor 1 (CB1R) and fatty acid amide hydrolase (FAAH) in cat ovary and oviduct, using paraffin-embedded tissue samples and commercially available antibodies. We found a differential expression of both CB1R and FAAH during different stages of ovarian function and in the oviduct. CB1R was detected only in tertiary follicle granulosa cells while more immature follicles were negative. FAAH was instead found in ovarian pre-antral follicles, the oocyte cytoplasm, and in granulosa cells of primary, secondary and tertiary follicles. Secondary and tertiary follicles were also FAAH immunoreactive. Luteal cells were immunopositive for both CB1R and FAAH. Because CBR1 in oviduct was found only in ciliated cells, it might represent a specific marker at least in cats. In contrast, FAAH immunoreactivity was observed in both ciliated and non-ciliated cells. The present study may thus serve as the starting point for further investigations on the role of the endocannabinoid system in cat reproduction. Additional work will be needed to assess whether the morphological distribution of CB1R and FAAH changes in different conditions such as pre-pubertal age, follicular phase of the sexual cycle and pregnancy.

CB1 cannabinoid receptor drives oocyte maturation and embryo development via PI3K/Akt and MAPK pathways

Endocannabinoids have been recognized as mediators of practically all reproductive events in mammals. However, little is known about the role of this system in oocyte maturation. In a mouse model, we observed that activation of cannabinoid receptor 1 (CB₁) during in vitro oocyte maturation modulated the phosphorylation status of Akt and ERK1/2 and enhanced the subsequent embryo production. In the absence of CB₁, in vivo oocyte maturation was impaired and embryo development delayed. Cannabinoid receptor 2 (CB₂) was unable to rescue these effects. Finally, we confirmed abnormal oocyte maturation rather than impaired embryonic transport through the oviduct in CB₁ knockouts. Our data suggest that cannabinoid agonists may be useful in vitro maturation supplements. For in vitro fertilization patients intolerant to gonadotropins, this could be a promising and only option.-López-Cardona, A. P., Pérez-Cerezales, S., Fernández-González, R., Laguna-Barraza, R., Pericuesta, E., Agirregoitia, N., Gutiérrez-Adán, A., Agirregoitia, E. CB₁ cannabinoid receptor drives oocyte maturation and embryo development via PI3K/Akt and MAPK pathways.

Dynamic of expression and localization of cannabinoid-degrading enzymes FAAH and MGLL in relation to CB1 during meiotic maturation of human oocytes

The endogenous cannabinoid system has been characterized in some female reproductive organs but little is known about the expression and localization pattern of cannabinoid-degrading enzymes in relation to the CB1 cannabinoid receptor in human oocytes. In this study, we focus on the investigation of the presence and differential distribution of fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGLL) in relation to CB1 during the maturation of human oocytes. We used a total of 290 human oocytes not suitable for in vitro fertilization/intracytoplasmic sperm injection (ICSI): germinal-vesicle (GV) and metaphase-I (MI) stages and metaphase-II (MII) oocytes that had not developed into an embryo after ICSI. Cannabinoid-degrading enzymes and the cannabinoid CB1 receptor were present in human oocytes. Specifically, FAAH was detected in the periphery of the oocyte from the GV to MI stage and co-localized with CB1. Later, by the MII stage, FAAH was spread within the oocyte, whereas MGLL immunostaining was homogeneous across the oocyte at all stages of maturation and only overlapped with CB1 at the GV stage. This coordinated redistribution of cannabinoid system proteins suggests a role for this system in the maturation of the female gamete.

Dynamics of expression and localization of the cannabinoid system in granulosa cells during oocyte nuclear maturation

OBJECTIVE

To describe the expression of cannabinoid receptors CB1 and CB2 and cannabinoid-degrading enzymes fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGLL) in human granulosa cells and to investigate their differential distribution with respect to CB1 at various stages during the nuclear maturation of the oocyte.

DESIGN

Analysis of granulosa cells from germinal vesicle (GV), metaphase I (MI), and MII oocytes by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and indirect immunofluorescence assays.

SETTING

Academic research laboratory.

PATIENT(S)

Patients from the Human Reproduction Unit of Cruces University Hospital undergoing intracytoplasmic sperm injection.

INTERVENTION(S)

We analyzed the granulosa cells of 300 oocytes from 53 patients. The oocyte maturation stages were 75 at GV stage, 51 at MI, and 174 at MII.

MAIN OUTCOME MEASURE(S)

The mRNA and protein expression of CB1, CB2, FAAH, and MGLL and localization in granulosa cells at each oocyte maturation stage.

RESULT(S)

CB1, FAAH, and MGLL are present in human granulosa cells during oocyte maturation, but the presence of CB2 receptor is not entirely clear in those cells. CB1 and FAAH were detected in the periphery of the granulosa cells from the GV to the MII oocytes, and they colocalized in some portions of the cell membrane. On the other hand, MGLL immunostaining was more homogeneous across the cell and overlapped with CB1 only weakly.

CONCLUSION(S)

The presence of the cannabinoid system in granulosa cells suggests a possible role of this system in the nuclear maturation of the oocyte.

Validation of endogenous control reference genes for normalizing gene expression studies in endometrial carcinoma

Real-time quantitative RT-PCR (qRT-PCR) is a powerful technique used for the relative quantification of target genes, using reference (housekeeping) genes for normalization to ensure the generation of accurate and robust data. A systematic examination of the suitability of endogenous reference genes for gene expression studies in endometrial cancer tissues is absent. The aims of this study were therefore to identify and evaluate from the thirty-two possible reference genes from a TaqMan(®) array panel their suitability as an internal control gene. The mathematical software packages geNorm qBasePLUS identified Pumilio homolog 1 (Drosophila) (PUM1), ubiquitin C (UBC), phosphoglycerate kinase (PGK1), mitochondrial ribosomal protein L19 (MRPL19) and peptidylpropyl isomerase A (cyclophilin A) (PPIA) as the best reference gene combination, whilst NormFinder identified MRPL19 as the best single reference gene, with importin 8 (IPO8) and PPIA being the best combination of two reference genes. BestKeeper ranked MRPL19 as the most stably expressed gene. In addition, the study was validated by examining the relative expression of a test gene, which encodes the cannabinoid receptor 1 (CB1). A significant difference in CB1 mRNA expression between malignant and normal endometrium using MRPL19, PPIA, and IP08 in combination was observed. The use of MRPL19, IPO8 and PPIA was identified as the best reference gene combination for the normalization of gene expression levels in endometrial carcinoma. This study demonstrates that the arbitrary selection of endogenous control reference genes for normalization in qRT-PCR studies of endometrial carcinoma, without validation, risks the production of inaccurate data and should therefore be discouraged.

The evolving role of the endocannabinoid system in gynaecological cancer

BACKGROUND

The 'endocannabinoid system' (ECS), comprising endogenous ligands (endocannabinoids) and their regulating enzymes, together with the cannabinoid receptors, has attracted a great deal of attention because it affects not only all facets of human reproduction, from gametogenesis through to parturition and beyond, but also targets key mechanisms affecting some hallmarks of cancer. Recent evidence showing that cannabinoid receptors play a very important role in the development of malignancies outside of the reproductive organs suggests a similar role for the ECS in the establishment or continued development of gynaecological malignancy.

METHODS

Primary papers and review articles, and primary sources within these papers, up to December 2014, on the evolving role of the ECS in cancer, with a special focus on gynaecological cancers, were obtained by Medline and PubMed searches using the search terms: 'cancer', 'cannabinoid', 'endocannabinoid', 'gynaecology' and 'malignancy'. Non-English manuscripts were excluded.

RESULTS

More than 2100 sources were obtained from which only 112 were specifically important to the topic. Analysis of those articles supports a role of the ECS in gynaecological cancers but leaves many gaps in our knowledge that need to be filled. How some of the relevant receptors are activated and cause changes in cell phenotypes that progress to malignancy remains undiscovered and an area for future research. Increasing evidence suggests that malignant transformation within the female genital tract could be accompanied by deregulation of components of the ECS, acting through rather complex cannabinoid receptor-dependent and receptor-independent mechanisms.

CONCLUSIONS

The paucity of studies in this area suggests that research using animal models is needed to evaluate endocannabinoid signalling in cancer networks. Future randomized clinical studies should reveal whether endocannabinoids or their derivatives prove to be useful therapeutic targets for gynaecological and other cancers.

Endocannabinoid signaling at the periphery: 50 years after THC

In 1964, the psychoactive ingredient of Cannabis sativa, Δ(9)-tetrahydrocannabinol (THC), was isolated. Nearly 30 years later the endogenous counterparts of THC, collectively termed endocannabinoids (eCBs), were discovered: N-arachidonoylethanolamine (anandamide) (AEA) in 1992 and 2-arachidonoylglycerol (2-AG) in 1995. Since then, considerable research has shed light on the impact of eCBs on human health and disease, identifying an ensemble of proteins that bind, synthesize, and degrade them and that together form the eCB system (ECS). eCBs control basic biological processes including cell choice between survival and death and progenitor/stem cell proliferation and differentiation. Unsurprisingly, in the past two decades eCBs have been recognized as key mediators of several aspects of human pathophysiology and thus have emerged to be among the most widespread and versatile signaling molecules ever discovered. Here some of the pioneers of this research field review the state of the art of critical eCB functions in peripheral organs. Our community effort is aimed at establishing consensus views on the relevance of the peripheral ECS for human health and disease pathogenesis, as well as highlighting emerging challenges and therapeutic hopes.

Decreased circulating anandamide levels in preeclampsia

The endocannabinoid system has a key role in female reproduction, including implantation, decidualization and placentation. A growing number of studies indicate that placental and peripheral blood anandamide levels correlate closely with both spontaneous miscarriage and ectopic pregnancy. Anandamide has also been implicated in blood pressure regulation. In this study, we aimed to determine circulating anandamide levels in preeclampsia for the first time in the literature. Forty-three preeclamptic patients and 71 healthy pregnant women were involved in this case-control study. Serum anandamide concentrations were determined by high-performance liquid chromatography-mass spectrometry technique. Serum total soluble fms-like tyrosine kinase-1 (sFlt-1) and biologically active placental growth factor (PlGF) levels were measured by electrochemiluminescence immunoassay. For statistical analyses, nonparametric methods were applied. Serum levels of anandamide were significantly lower in preeclamptic patients than in healthy pregnant women (0.75 (0.44-1.03) ng ml(-1) vs. 1.30 (0.76-2.0) ng ml(-1), P<0.001). Preeclamptic patients had significantly higher sFlt-1 levels (12,121 (7963-18,316) pg ml(-1) vs. 2299 (1393-3179) pg ml(-1), P<0.001) and significantly lower PlGF concentrations (71.2 (39.2-86.4) pg ml(-1) vs. 256.8 (181.1-421.0) pg ml(-1), P<0.001) as compared with healthy pregnant women. Serum anandamide concentrations did not correlate with serum levels of sFlt-1 and PlGF in our healthy pregnant and preeclamptic groups. In conclusion, we demonstrated for the first time in the literature that serum anandamide concentrations are decreased in women with preeclampsia. However, the cause and consequence of this observation remain to be determined.

Endocannabinoids and Reproductive Events in Health and Disease

The lasting research on the endocannabinoid system (ECS) has now provided solid and convincing evidence that proves the detrimental effects of recreational drug abuse (a growing habit among teenagers) on fertility. Endocannabinoids (eCBs) affect reproductive events from gametogenesis to fertilization, from embryo implantation to the final outcome of pregnancy and, thus, they have been proposed as suitable biomarkers to predict the reproductive potential of male and female gametes in clinical practice. Novel tools for reproductive medicine are highly sought after, and here we report the latest findings on the impact of the ECS on fertility, demonstrating how basic research can be translated into new medical strategies.

Relationship between seminal plasma levels of anandamide congeners palmitoylethanolamide and oleoylethanolamide and semen quality

OBJECTIVE

To determine whether changes in seminal plasma concentrations of the endogenous lipid signaling molecules palmitoylethanolamide (PEA) and oleoylethanolamide (OEA) have significant effects on sperm quality.

DESIGN

Biochemical and physiological studies of human seminal plasma and spermatozoa.

SETTING

Academic tertiary care medical center.

PATIENT(S)

Ninety men attending an infertility clinic for semen analysis.

INTERVENTION(S)

Palmitoylethanolamide and OEA extracted from seminal plasma were quantified by ultra high-performance liquid chromatography (HPLC)-tandem mass spectrometry. Patient sperm from semen with normal parameters were exposed in vitro to PEA or OEA to determine effects on sperm motility, viability, and mitochondrial activity.

MAIN OUTCOME MEASURE(S)

The relationship between seminal plasma concentrations of PEA and OEA and sperm quality and the effect of these compounds on sperm motility, viability, and mitochondria activity in vitro.

RESULT(S)

Palmitoylethanolamide and OEA concentrations in seminal plasma were lower in men with asthenozoospermia and oligoasthenoteratozospermia compared with men with normal semen parameters. Palmitoylethanolamide and OEA rapidly and significantly improved sperm motility and maintained viability without affecting mitochondria activity in vitro.

CONCLUSION(S)

Maintenance of normal PEA and OEA tone in human seminal plasma may be necessary for the preservation of normal sperm function and male fertility. Exocannabinoids found in Cannabis, such as delta-9-tetrahydrocannabinol and cannabidiol, could compete with these endocannabinoids upsetting their finely balanced, normal functioning and resulting in male reproductive failure.

MicroRNA and implantation

We provide a review of microRNA (miRNA) related to human implantation which shows the potential diagnostic role of miRNAs in impaired endometrial receptivity, altered embryo development, implantation failure after assisted reproduction technology, and in ectopic pregnancy and pregnancies of unknown location. MicroRNAs may be emerging diagnostic markers and potential therapeutic tools for understanding implantation disorders. However, further research is needed before miRNAs can be used in clinical practice for identifying and treating implantation failure.

Synthetic cannabinoids and potential reproductive consequences

Increases in emergency room visits due to abuse of designer drugs, popularly known by the street names "K2" and "Spice," are a cause for social, judicial, and clinical concerns. The psychoactive components in these herbal drugs mainly consist of different synthetic cannabinoids, and users of these street drugs are primarily within the age group of 12 to 20years old. The abusive use of synthetic cannabinoids results in anxiety, nausea, vomiting, tachycardia, elevated blood pressure, tremors, seizures, hallucinations, and paranoid behavior, but the effects of maternal use of synthetic cannabinoids during pregnancy are ambiguous due to limited studies in humans and a relative short history of the drugs. In this review, we discuss the known and potential adverse effects of synthetic cannabinoids on human pregnancy using knowledge gathered from studies in mice and limited studies in humans. In mice, multiple sites and stages of pregnancy are potential targets of synthetic cannabinoids, including preimplantation embryo development, oviductal embryo transport, implantation, placentation, and parturition. It is anticipated that maternal use of synthetic cannabinoids would result in severely compromised female fertility and pregnancy outcome.

Endocannabinoids as biomarkers of human reproduction

BACKGROUND

Infertility is a condition of the reproductive system that affects ∼10-15% of couples attempting to conceive a baby. More than half of all cases of infertility are a result of female conditions, while the remaining cases can be attributed to male factors, or to a combination of both. The search for suitable biomarkers of pregnancy outcome is a challenging issue in human reproduction, aimed at identifying molecules with predictive significance of the reproductive potential of male and female gametes. Among the various candidates, endocannabinoids (eCBs), and in particular anandamide (AEA), represent potential biomarkers of human fertility disturbances. Any perturbation of the balance between synthesis and degradation of eCBs will result in local changes of their tone in human female and male reproductive tracts, which in turn regulates various pathophysiological processes, oocyte and sperm maturation included.

METHODS

PubMed and Web of Science databases were searched for papers using relevant keywords like 'biomarker', 'endocannabinoid', 'infertility', 'pregnancy' and 'reproduction'.

RESULTS

In this review, we discuss different studies on the measurements of AEA and related eCBs in human reproductive cells, tissues and fluids, where the local contribution of these bioactive lipids could be critical in ensuring normal sperm fertilizing ability and pregnancy.

CONCLUSION

Based on the available data, we suggest that the AEA tone has the potential to be exploited as a novel diagnostic biomarker of infertility, to be used in association with assays of conventional hormones (e.g. progesterone, β-chorionic gonadotrophin) and semen analysis. However further quantitative research of its predictive capacity is required.

Updates in reproduction coming from the endocannabinoid system

The endocannabinoid system (ECS) is an evolutionarily conserved master system deeply involved in the central and local control of reproductive functions in both sexes. The tone of these lipid mediators-deeply modulated by the activity of biosynthetic and hydrolyzing machineries-regulates reproductive functions from gonadotropin discharge and steroid biosynthesis to the formation of high quality gametes and successful pregnancy. This review provides an overview on ECS and reproduction and focuses on the insights in the regulation of endocannabinoid production by steroids, in the regulation of male reproductive activity, and in placentation and parturition. Taken all together, evidences emerge that the activity of the ECS is crucial for procreation and may represent a target for the therapeutic exploitation of infertility.

First evidence of the interaction between deleted in malignant brain tumor 1 and galectin-3 in the mammalian oviduct

The oviduct supports the transport and final maturation of gametes, and harbors fertilization and early embryo development. The oviductal epithelium is responsible for providing the correct environment for these processes. Deleted in malignant brain tumor 1 (DMBT1) is expressed by multiple organisms and several cell types, and the interaction of the rabbit ortholog of DMBT1 with galectin-3 (gal-3) modulates the polarity of epithelial cells. This interaction has not yet been shown in locations other than rabbit kidney and human-cultured endothelial cells. DMBT1 and gal-3 also protect epithelial layers from pathogens and trauma, and are innate immunity components. DMBT1 has been detected in the porcine oviduct, and gal-3 has been reported in the Fallopian tube and in the cow oviduct. Interaction between both proteins would show a probable physiological function in the female reproductive tract. This work describes the presence and co-localization of DMBT1 and gal-3 mainly in the apical region of the epithelial cells of the Fallopian tube and the porcine oviduct, and co-immunoprecipitation in membrane-enriched epithelial cell extracts from the porcine oviduct. The findings strongly support a functional interaction in the mammalian oviduct, suggestive of a role on epithelial protection and homeostasis, which might be related to epithelium-gamete interaction.

Anandamide levels fluctuate in the bovine oviduct during the oestrous cycle

Mammalian oviduct acts as a reservoir for spermatozoa and provides an environment in which they may compete for the opportunity to fertilize the oocyte. Whilst in the oviduct spermatozoa undergo capacitation essential for fertilization. Sperm-oviduct interaction is essential for sperm capacitation and is a tightly regulated process influenced by the local microenvironment. Previously we reported that the endocannabinoid anandamide (AEA) regulates sperm release from epithelial oviductal cells by promoting sperm capacitation. The aims of this work were to measure the AEA content and to characterize the main AEA metabolic pathway in the bovine oviduct and determine how these change through the oestrous cycle. In this study, the levels of AEA and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in bovine oviduct collected during different stages of oestrous cycle by ultra high performance liquid chromatography tandem mass spectrometry. Results indicated that intracellular oviductal epithelial levels of all three N-acylethanolamines fluctuate during oestrous cycle. Anandamide from oviductal fluid also varied during oestrous cycle, with the highest values detected during the periovulatory period. Endocannabinoid levels from ipsilateral oviduct to ovulation were higher than those detected in the contralateral one, suggesting that levels of oviductal AEA may be regulated by ovarian hormones. The expression and localization of N-acylethanolamines metabolizing enzymes in bovine oviduct were also determined by RT-PCR, Western blot, and immunohistochemistry but no change was found during the oestrous cycle. Furthermore, nanomolar levels of AEA were detected in follicular fluids, suggesting that during ovulation the mature follicle may contribute to oviductal AEA levels to create an endocannabinoid gradient conducive to the regulation of sperm function for successful fertilization.

The role of endocannabinoids in pregnancy

Endocannabinoids are a family of lipid signalling molecules. As with prostaglandins (PGs), endocannabinoids are derived from polyunsaturated fatty acids and affect cell function via receptor-mediated mechanisms. They also bind to PG receptors, although at a lower affinity. The endocannabinoid network is regulated in pregnancy from embryo development to labour onset. Even small changes in endocannabinoid exposure can retard embryo development and affect implantation success. There is now compelling evidence that aberrant expression of factors involved in the endocannabinoid pathway in the placenta and circulating lymphocytes results in spontaneous miscarriage and poor pregnancy outcomes. It is likely that competition between endocannabinoids, PGs and other similar lipids ultimately determines how phospholipid/fatty acid substrates are metabolised and, thus, the balance between the uterotonic and tocolytic activities. We, therefore, hypothesise that endocannabinoid profiles may be used as a biomarker to predict and/or identify spontaneous labour onset.

Elevated anandamide and related N-acylethanolamine levels occur in the peripheral blood of women with ectopic pregnancy and are mirrored by changes in peripheral fatty acid amide hydrolase activity

BACKGROUND

Studies from knockout mice suggest that perturbations in oviductal endocannabinoid levels, endocannabinoid receptors, or endocannabinoid degrading enzyme [fatty acid amide hydrolase (FAAH)] expression result in infertility secondary to physical trapping of embryos. Similar observations have been made in ectopic pregnant women together with a suggestion that the endocannabinoid receptor gene polymorphism 1359G/A (rs1049353) is associated with ectopic pregnancy. These observations led to the hypothesis that ectopic pregnancy is associated with a perturbation in levels of endocannabinoids and FAAH activity and that such changes are associated with impaired tubal function.

AIMS

The objective of the study was to quantify the plasma levels of endocannabinoids (anandamide, oleoylethanolamide, and palmitoylethanolamide) and evaluate blood endocannabinoid metabolizing enzyme activities FAAH and N-acyl-phosphatidyl-ethanolamine phospholipase D (NAPE-PLD) in ectopic pregnancy and normal pregnant controls and relate that to β-human chorionic gonadotropin (β-hCG) levels. Additionally, we wanted to examine the effect of endocannabinoids on cilia beat frequency in Fallopian tube epithelial cells ex vivo.

PARTICIPANTS AND METHODS

Whole blood collected from ectopic and normal pregnancies was used for quantification of plasma endocannabinoid levels by ultra-HPLC-tandem mass spectrometry of FAAH and NAPE-PLD enzyme activities by radiometric assays, and β-hCG by immunoassay. Fallopian tube epithelial cells from healthy volunteers were treated with endocannabinoids and cilia beat frequency analyzed using a high-speed digital camera and CiliaFA software.

RESULTS

FAAH activity (P < .05) but not NAPE-PLD activity was significantly reduced in ectopic pregnancies. All 3 endocannabinoids levels were significantly higher (P < .05) in ectopic pregnancy. There was no correlation between endocannabinoids, enzyme activity, and β-hCG levels. Oleoylethanolamide (P < .05), but not methanandamide or palmitoylethanolamide, significantly decreased cilia beat frequency in Fallopian tube epithelial cells.

CONCLUSION

Elevated endocannabinoid levels and reduced FAAH activity are associated with ectopic pregnancy and may modulate tubal function, suggesting dysfunctional endocannabinoid action in ectopic implantation. Oleoylethanolamide may play a critical role in embryo-tubal transport.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.