Induction of follicular growth by exogenous interleukin-8

A review of autoimmunity and immune profiles in patients with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a complicated clinical syndrome characterized by progressive deterioration of ovarian function. Autoimmunity is one of the main pathogenic factors affecting approximately 10% to 55% of POI cases. This review mainly focuses on the role of autoimmunity in the pathophysiology of POI and the potential therapies for autoimmunity-related POI. This review concluded that various markers of ovarian reserve, principally anti-Müllerian hormone, could be negatively affected by autoimmune diseases. The presence of lymphocytic oophoritis, anti-ovarian autoantibodies, and concurrent autoimmune diseases, are the main characteristics of autoimmune POI. T lymphocytes play the most important role in the immune pathogenesis of POI, followed by disorders of other immune cells and the imbalance between pro-inflammatory and anti-inflammatory cytokines. A comprehensive understanding of immune characteristics of patients with autoimmune POI and the underlying mechanisms is essential for novel approaches of treatment and intervention for autoimmune POI.

Mast Cell Activation Syndrome in COVID-19 and Female Reproductive Function: Theoretical Background vs. Accumulating Clinical Evidence

Coronavirus disease 2019 (COVID-19), a pandemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, can affect almost all systems and organs of the human body, including those responsible for reproductive function in women. The multisystem inflammatory response in COVID-19 shows many analogies with mast cell activation syndrome (MCAS), and MCAS may be an important component in the course of COVID-19. Of note, the female sex hormones estradiol (E2) and progesterone (P4) significantly influence mast cell (MC) behavior. This review presents the importance of MCs and the mediators from their granules in the female reproductive system, including pregnancy, and discusses the mechanism of potential disorders related to MCAS. Then, the available data on COVID-19 in the context of hormonal disorders, the course of endometriosis, female fertility, and the course of pregnancy were compiled to verify intuitively predicted threats. Surprisingly, although COVID-19 hyperinflammation and post-COVID-19 illness may be rooted in MCAS, the available clinical data do not provide grounds for treating this mechanism as significantly increasing the risk of abnormal female reproductive function, including pregnancy. Further studies in the context of post COVID-19 condition (long COVID), where inflammation and a procoagulative state resemble many aspects of MCAS, are needed.

Ovarian and endometrial immunity during the ovarian cycle

Immune tolerance is crucial for the successful pregnancy, while immune effectors and their products are required to safeguard a fetus from the infectious pathogens. The key immune effectors, such as T, B, and natural killer (NK) cells, monocytes, macrophages, and dendritic cells take part in regulating the immune responses at the maternal-fetal interface. The immune effectors become involved in intraovarian reproductive processes as well, such as ovulation, production of corpus luteum (CL) and its degeneration and determine the quality and evolution of the oocyte during the folliculogenesis. In the cycling endometrium, NK cells are rapidly infiltrated into the endometrium after ovulation and participate in angiogenesis and spiral artery remodeling process. In this study, we reviewed the characteristics and action mechanisms of immune effectors and their products in the peripheral blood, ovary, and endometrium during the ovarian cycle, since a comprehensive understanding of immune responses during the ovarian cycle and the time of implantation can help us to predict the pregnancy outcome and take effective measures for the prevention of potential obstetrical complications.

Cellular and molecular mechanisms of the preovulatory follicle differenciation and ovulation: What do we know in the mare relative to other species

Terminal follicular differentiation and ovulation are essential steps of reproduction. They are induced by the increase in circulating LH, and lead to the expulsion from the ovary of oocytes ready to be fertilized. This review summarizes our current understanding of cellular and molecular pathways that control ovulation using a broad mammalian literature, with a specific focus to the mare, which is unique in some aspects of ovarian function in some cases. Essential steps and key factors are approached. The first part of this review concerns LH, receptors and signaling, addressing the description of the equine gonadotropin and cloning, signaling pathways that are activated following the binding of LH to its receptors, and implication of transcription factors which better known are CCAAT-enhancer-binding proteins (CEBP) and cAMP response element-binding protein (CREB). The second and major part is devoted to the cellular and molecular actors within follicular cells during preovulatory maturation. We relate to 1) molecules involved in vascular permeability and vasoconstriction, 2) involvement of neuropeptides, such as kisspeptin, neurotrophins and neuronal growth factor, neuropeptide Y (NPY), 3) the modification of steroidogenesis, steroids intrafollicular levels and enzymes activity, 4) the local inflammation, with the increase in prostaglandins synthesis, and implication of leukotrienes, cytokines and glucocorticoids, 5) extracellular matrix remodelling with involvement of proteases, antiproteases and inhibitors, as well as relaxin, and finaly 6) the implication of oxytocine, osteopontin, growth factors and reactive oxygen species. The third part describes our current knowledge on molecular aspect of in vivo cumulus-oocyte-complexe maturation, with a specific focus on signaling pathways, paracrine factors, and intracellular regulations that occur in cumulus cells during expansion, and in the oocyte during nuclear and cytoplasmic meiosis resumption. Our aim was to give an overall and comprehensive map of the regulatory mechanisms that intervene within the preovulatory follicle during differentiation and ovulation.

Human granulosa-luteal cells initiate an innate immune response to pathogen-associated molecules

The microenvironment of the ovarian follicle is key to the developmental success of the oocyte. Minor changes within the follicular microenvironment can significantly disrupt oocyte development, compromising the formation of competent embryos and reducing fertility. Previously described as a sterile environment, the ovarian follicle of women has been shown to contain colonizing bacterial strains, whereas in domestic species, pathogen-associated molecules are concentrated in the follicular fluid of animals with uterine infection. The aim of this study is to determine whether human granulosa-luteal cells mount an innate immune response to pathogen-associated molecules, potentially disrupting the microenvironment of the ovarian follicle. Human granulosa-luteal cells were collected from patients undergoing assisted reproduction. Cells were cultured in the presence of pathogen-associated molecules (LPS, FSL-1 and Pam3CSK4) for 24h. Supernatants and total RNA were collected for assessment by PCR and ELISA. Granulosa-luteal cells were shown to express the molecular machinery required to respond to a range of pathogen-associated molecules. Expression of TLR4 varied up to 15-fold between individual patients. Granulosa-luteal cells increased the expression of the inflammatory mediators IL1B, IL6 and CXCL8 in the presence of the TLR4 agonist E. coli LPS. Similarly, the TLR2/6 ligand, FSL-1, increased the expression of IL6 and CXCL8. Although no detectable changes in CYP19A1 or STAR expression were observed in granulosa-luteal cells following challenge, a significant reduction in progesterone secretion was measured after treatment with FSL-1. These findings demonstrate the ability of human granulosa-luteal cells to respond to pathogen-associated molecules and generate an innate immune response.

Gonadotrophin stimulation in IVF alters the immune cell profile in follicular fluid and the cytokine concentrations in follicular fluid and serum

Study question

Are the immune cell profiles and the cytokine concentrations in follicular fluid (FF) and serum at the preovulatory stage different in conventional exogenous gonadotrophin stimulated IVF (c-IVF) compared with natural cycle IVF (NC-IVF)?

Summary answer

The cell counts of CD45+ leucocytes and T cell subpopulations and the cytokine concentrations in FF and serum are different in c-IVF compared to NC-IVF.

What is known already

FF-derived cells are heterogeneous. Immune cells are involved in intra-ovarian processes and cytokines are required for normal follicular development. Gonadotrophins stimulate the regulatory intrafollicular system and influence the local distribution of immune cells and the intrafollicular release of cytokines. Administration of exogenous gonadotrophins may have a significant effect on this local regulatory system, which then in turn could influence oocyte quality.

Study design, size, duration

The study included 105 patients, 69 undergoing c-IVF and 36 undergoing NC-IVF. c-IVF was performed by exogenous ovarian stimulation with hMG and GnRH antagonists.

Participants/materials, setting, methods

FF samples were collected from the first dominant follicle in c-IVF without pooling and from single leading preovulatory follicles in NC-IVF. Three different approaches were used to analyze FF samples: (i) microscopic investigation of CD45+ leucocytes, (ii) fluorescence-activated cell sorting to determine CD19+ B cells and CD3+ T cells including T cell subpopulations (CD4+, CD8+), and (iii) evaluation of tumour necrosis factor-alpha (TNF-α), interferon-gamma (INF-γ), interleukins (IL)-2, -6, -8, -10 and vascular endothelial growth factor (VEGF) levels in matched FF and serum samples using the Bio-Plex® platform.

Main results and the role of chance

FF obtained from c-IVF contained proportionally more CD45+ leucocytes (P = 0.0384), but fewer CD8+ cytotoxic T cells than FF from NC-IVF. CD3+ T lymphocytes were the most common type of lymphocytes, and the number thereof was comparable in the two study groups. In c-IVF, serum VEGF levels were higher (P = 0.007) than in NC-IVF while FF contained marginally decreased concentrations of IL-8 in c-IVF in comparison to NC-IVF. The cytokine concentration gradient between FF and serum in c-IVF was 10-fold for IL-8 and 8-fold for VEGF and thereby markedly lower than in NC-IVF, where the differences were 32-fold and 30-fold, respectively. Strong positive correlations were determined between FF- IL-10 and FF- VEGF in c-IVF (r = 0.85, P < 0.0001) and in NC-IVF (r = 0.81, P < 0.0001).

Large scale data

N/A.

Limitations, reasons for caution

The ovulation of NC-IVF follicles was induced by the exogenous administration of hCG, which means that the environment did not fully correspond to the physiological situation.

Wider implications of the findings

The differences in the immune profile and the cytokine concentrations in c-IVF and NC-IVF follicles support the hypothesis that conventional ovarian stimulation affects indirectly and heterogeneously the intrafollicular milieu, and thereby possibly affects the oocyte quality and the IVF outcome. However, further studies are needed to confirm our findings and to refine stimulation protocols in the context of optimizing the intrafollicular environment during oocyte maturation.

Study funding/competing interest(s)

The study was supported by a research grant from IBSA Institut Biochimique SA and MSD Merck Sharp & Dohme GmbH. The authors are clinically involved in low dose mono-follicular stimulation and IVF-therapies, using gonadotrophins from all gonadotrophins distributors on the Swiss market, including Institut Biochimique SA and MSD Merck Sharp & Dohme GmbH.

Novel effects of the cyclooxygenase-2-selective inhibitor NS-398 on IL-1β-induced cyclooxygenase-2 and IL-8 expression in human ovarian granulosa cells

Ovulation is a critical inflammation-like event that is central to ovarian physiology. IL-1β is an immediate early pro-inflammatory cytokine that regulates production of several other inflammatory mediators, such as cyclooxygenase 2 (COX)-2 and IL-8. NS-398 is a selective inhibitor of COX-2 bioactivity and thus this drug is able to mitigate the COX-2-mediated production of downstream prostaglandins and the subsequent inflammatory response. Here we have investigated the action of NS-398 using a human ovarian granulosa cell line, KGN, by exploring IL-1β-regulated COX-2 and IL-8 expression. First, NS-398, instead of reducing inflammation, appeared to further enhance IL-1β-mediated COX-2 and IL-8 production. Using selective inhibitors targeting various signaling molecules, MAPK and NF-κB pathways both seemed to be involved in the impact of NS-398 on IL-1β-induced COX-2 and IL-8 expression. NS-398 also promoted IL-1β-mediated NF-κB p65 nuclear translocation but had no effect on IL-1β-activated MAPK phosphorylation. Flow cytometry analysis demonstrated that NS-398, in combination with IL-1β, significantly enhanced cell cycle progression involving IL-8. Our findings demonstrate a clear pro-inflammatory function for NS-398 in the IL-1β-mediated inflammatory response of granulosa cells, at least in part, owing to its augmenting effect on the IL-1β-induced activation of NF-κB.

Alterations in adhesion molecules, pro-inflammatory cytokines and cell-derived microparticles contribute to intima-media thickness and symptoms in postmenopausal women

Menopause, the cessation of menses, occurs with estrogens decline, low-grade inflammation, and impaired endothelial function, contributing to atherosclerotic risk. Intima-media thickness (IMT) is an early subclinical biomarker of atherosclerosis. Inflammation may have a role on symptoms: hot flashes, anxiety, and depressive mood, which also are related to endothelial dysfunction, increased IMT and cardiovascular risk. In this study we compared several inflammatory markers in early vs. late postmenopausal women and studied the association of IMT and symptoms with these markers in the full sample. In a cross-sectional design including 60 women (53.1 ± 4.4 years old) at early and late postmenopause, we evaluated the expression of CD62L, ICAM-1, PSGL-1, CD11b, CD11c, and IL-8R on PBMC by flow cytometry. Serum soluble ICAM-1, sVCAM-1, sCD62E, sCD62P, CXCL8, IL-1β, IL-6, and TNF-α levels were quantified by ELISA. Plasma levels of microparticles (MPs) were determined by FACS. Finally, carotid intima-media thickness (IMT) was measured by ultrasound. We observed that ICAM-1 expression by lymphocytes and serum sVCAM-1 levels were augmented at late postmenopause. Late postmenopause women with severe hot flashes had increased expression of CD62L and IL-8R on neutrophils. By multivariate analysis, the carotid IMT was strongly associated with membrane-bound TNF-α, CD11b expression, Annexin V(+) CD3(+) MPs, LPS-induced NO production, HDL-cholesterol and age. Depressive mood was associated negatively with PSGL-1 and positively with LPS-induced NO. Finally, Log(AMH) levels were associated with carotid IMT, IL-8R expression and time since menopause. IMT and depressive mood were the main clinical features related to vascular inflammation. Aging, hormonal changes and obesity were also related to endothelial dysfunction. These findings provide further evidence for a link between estrogen deficiency and low-grade inflammation in endothelial impairment in mature women.

Effects of interleukin-8 on estradiol and progesterone production by bovine granulosa cells from large follicles and progesterone production by luteinizing granulosa cells in culture

Interleukin 8 (IL-8) is a chemoattractant involved in the recruitment and activation of neutrophils and is associated with the ovulate process. We examined the possible role of IL-8 in steroid production by bovine granulosa cells before and after ovulation. The concentration of IL-8 in the follicular fluid of estrogen-active dominant (EAD) and pre-ovulatory follicles (POF) was higher than that of small follicles (SF). CXCR1 mRNA expression was higher in the granulosa cells of EAD and POF than that of SF. In contrast, CXCR2 mRNA expression was lower in granulosa cells of EAD and POF than in SF. IL-8 inhibited estradiol (E2) production in follicle-stimulating hormone (FSH)-treated granulosa cells at 48 h of culture. IL-8 also suppressed CYP19A1 mRNA expression in FSH-treated granulosa cells. IL-8 stimulated progesterone (P4) production in luteinizing hormone (LH)-treated granulosa cells at 48 h of culture. Although IL-8 did not alter the expression of genes associated with P4 production, it induced StAR protein expression in LH-treated granulosa cells. The expression of CXCR1 mRNA in corpus luteum (CL) did not change during the luteal phase. In contrast, the expression of CXCR2 mRNA in middle CL was significantly higher than in early and regression CL during the luteal phase. In luteinizing granulosa cells, an in vitro model of granulosa cell luteinization, CXCR2 mRNA expression was downregulated, whereas CXCR1 mRNA expression was unchanged. IL-8 also stimulated P4 production in luteinizing granulosa cells. These data provide evidence that IL-8 functions not only as a chemokine, but also act as a regulator of steroid synthesis in granulosa cells to promote luteinization after ovulation.

Pathophysiological roles of chemokines in human reproduction: an overview

Chemokines are a group of small cytokines that have an ability to induce leukocyte migration. Chemokines exert their functions by binding and activating specific G protein-coupled receptors. Studies have unveiled pleiotropic bioactivities of chemokines in various phenomena ranging from immunomodulation, embryogenesis, and homeostasis to pathogenesis. In the mammalian reproductive system, chemokines unexceptionally serve in multimodal events that are closely associated with establishment, maintenance, and deterioration of fecundity. The aim of this review is to update the knowledge on chemokines in male and female genital organs, with a focus on their potential pathophysiological roles in human reproduction.

Morphological analyses of interleukin-8 effects on rat ovarian follicles at ovulation and luteinization in vivo

The aim of the present study was to elucidate functions of the interleukin (IL)-8 at ovulation and luteinization in vivo. To compare the morphological differences between human chorionic gonadotropin (hCG) and IL-8 stimulation, scanning electron microscopy was employed to study rat ovarian vascular corrosion casts. Follicular growth and increased capillary vessel densities around the follicles were seen in vascular corrosion casts after IL-8 injection, similar to the result of hCG administration. This result indicated that exogenous IL-8 could play a role in the neovascularization during follicular development as an angiogenetic factor. Many fenestrations were observed in the vascular endothelium by hCG administration. In contrast, no fenestrations were observed with IL-8 injection, indicating that IL-8 may not be sufficient to increase the vascular permeability directly. Although germinal vesicle breakdown (GVBD) occurred at rates of 82% after the hCG injection, only 20% GVBD was observed after the IL-8 injection. The present study indicated that IL-8 might have important effects on rat follicles at ovulation and luteinization via vascularization in a similar manner to hCG. However, IL-8 was not effective on vascular permeability and oocyte maturation, which were different from hCG. Thus, we can conclude that IL-8 can participate in follicular development in part and may play important roles in ovulation and luteinization as one of some mediators induced by endogenous luteinizing hormone.

Determination of Total Interleukin-8 in Whole Blood after Cell Lysis

Background: It has been shown that a high percentage of interleukin-8 (IL-8) in blood is cell associated. Recently, a simple method for determination of cell-associated IL-8 in whole blood after cell lysis has been described. The purpose of this study was to evaluate this method, to examine the influence of preanalytic sample handling, and to establish the concentration range of total IL-8 and its relation to age and sex in healthy subjects.

Methods: Total IL-8 content of whole blood was determined after lysing blood cells with Milenia® cell lysis solution. IL-8 in the resulting blood lysate was measured with the IMMULITE® IL-8 immunoassay.

Results: When freshly drawn blood was stored up to 48 h on ice, no significant changes in total IL-8 were measured in the subsequently prepared lysate, whereas with storage at room temperature, total IL-8 increased after 3 h from 94 ± 13 ng/L to 114 ± 16 ng/L (n = 10). In lysate stored for 48 h at 4 °C, marginal changes of the IL-8 concentration were noted, with storage at room temperature, only 76% ± 5% (n = 12) of initial concentration was recovered. From lysate frozen at −20 and −80 °C, respectively, 84% ± 4% and 93% ± 2% of initial IL-8 was recovered after 70 days (n = 10). IL-8 was measured with comparable precision in plasma (CV, 3.2–4.2%) and blood lysate (CV, 3.7–4.1%). When plasma was diluted with cell lysis solution, a slightly overestimated recovery (125% ± 3%) was observed; for lysate specimens with a cell lysis solution content ≥75%, the recovery after dilution was 98% ± 2%. In lysate prepared from 12 blood samples with exogenous IL-8 added, IL-8 recovery was 104% ± 2% (recovery from plasma &lt;35%). The median total IL-8 in blood lysates from 103 healthy subjects (22–61 years) was 83 ng/L of blood (2.5–97.5 percentile range, 49–202 ng/L of blood). In females but not in males, total IL-8 increased significantly with advancing age (P &lt;0.002). We found grossly increased total IL-8 in six pregnant women with amniotic infection syndrome.

Conclusions: The evaluated method allows the assessment of total IL-8 in blood with good performance when appropriate conditions of sample pretreatment are considered. The values in healthy volunteers all were above the detection limit of the IL-8 assay; therefore, slight changes of total IL-8 could be noted. Thus, the present method is a suitable tool to study the diagnostic relevance of total IL-8 in blood.

Potential implications of chemokines in reproductive function: an attractive idea

Chemokines are a new family of cytokines specialised in attracting leukocytes, acting in physiological conditions and in pathological processes. A wide variety of cell types in response to exogenous irritants or endogenous mediators of the inflammatory reaction produce them. Pivotal parts of reproductive function are based on inflammatory like processes wherein different leukocytes subsets are recruited and activated to produce paracrine autocrine effects in which cytokines and growth factors are implicated. Since chemokines control leukocyte trafficking and belong to the cytokine superfamily, in this review we analyze the implications of these molecules and related cells in ovulation, embryonic implantation, menstruation, parturition and their role in pathological process such as preterm delivery, endometriosis, ovarian hyperstimulation syndrome and HIV infection.