Regulation of the estrous cycle by neutrophil infiltration into the vagina

Progesterone promotes CXCl2-dependent vaginal neutrophil killing by activating cervical resident macrophage-neutrophil crosstalk

Vaginal infections in women of reproductive age represent a clinical dilemma with significant socioeconomic implications. The current understanding of mucosal immunity failure during early pathogenic invasions that allows the pathogen to grow and thrive is far from complete. Neutrophils infiltrate most tissues following circadian patterns as part of normal repair, regulation of microbiota, or immune surveillance and become more numerous after infection. Neutrophils are responsible for maintaining vaginal immunity. Specific to the vagina, neutrophils continuously infiltrate at high levels, although during ovulation, they retreat to avoid sperm damage and permit reproduction. Here we show that, after ovulation, progesterone promotes resident vaginal macrophage-neutrophil crosstalk by upregulating Yolk sac early fetal organs (FOLR2+) macrophage CXCl2 expression, in a TNFA-patrolling monocyte-derived macrophage-mediated (CX3CR1hiMHCIIhi-mediated) manner, to activate the neutrophils' capacity to eliminate sex-transmitted and opportunistic microorganisms. Indeed, progesterone plays an essential role in conciliating the balance between the commensal microbiota, sperm, and the threat of pathogens because progesterone not only promotes a flurry of neutrophils but also increases neutrophilic fury to restore immunity after ovulation to thwart pathogenic invasion after intercourse. Therefore, modest progesterone dysregulations could lead to a suboptimal neutrophilic response, resulting in insufficient mucosal defense and recurrent unresolved infections.

Casein kinase 1α mediates estradiol secretion via CYP19A1 expression in mouse ovarian granulosa cells

BACKGROUND

Casein kinase 1α (CK1α), expressed in both ovarian germ and somatic cells, is involved in the initial meiosis and primordial follicle formation of mouse oocytes. Using in vitro and in vivo experiments in this study, we explored the function and mechanism of CK1α in estrogen synthesis in mice ovarian granulosa cells.

METHODS

A CK1α knockout (cKO) mouse model, targeted specifically to ovarian granulosa cells (GCs), was employed to establish the influence of CK1α on in vivo estrogen synthesis. The influence of CK1α deficiency on GCs was determined in vivo and in vitro by immunofluorescence analysis and Western blot assay. Transcriptome profiling, differentially expressed genes and gene functional enrichment analyses, and computation protein-protein docking, were further employed to assess the CK1α pathway. Furthermore, wild-type female mice were treated with the CK1α antagonist D4476 to elucidate the CK1α's role in estrogen regulation.

RESULTS

Ovarian GCs CK1α deficiency impaired fertility and superovulation of female mice; also, the average litter size and the estradiol (E2) level in the serum of cKO female mice were decreased by 57.3% and 87.4% vs. control mice, respectively. This deficiency disrupted the estrous cycle and enhanced the apoptosis in the GCs. We observed that CK1α mediated the secretion of estradiol in mouse ovarian GCs via the cytochrome P450 subfamily 19 member 1 (CYP19A1).

CONCLUSIONS

These findings improve the existing understanding of the regulation mechanism of female reproduction and estrogen synthesis.

TRIAL REGISTRATION

Not applicable.

Extrusion of Neutrophil Extracellular Traps (NETs) Negatively Impacts Canine Sperm Functions: Implications in Reproductive Failure

Reproductive failure in dogs is often due to unknown causes, and correct diagnosis and treatment are not always achieved. This condition is associated with various congenital and acquired etiologies that develop inflammatory processes, causing an increase in the number of leukocytes within the female reproductive tract (FRT). An encounter between polymorphonuclear neutrophils (PMNs) and infectious agents or inflammation in the FRT could trigger neutrophil extracellular traps (NETs), which are associated with significantly decreased motility and damage to sperm functional parameters in other species, including humans. This study describes the interaction between canine PMNs and spermatozoa and characterizes the release of NETs, in addition to evaluating the consequences of these structures on canine sperm function. To identify and visualize NETs, May-Grünwald Giemsa staining and immunofluorescence for neutrophil elastase (NE) were performed on canine semen samples and sperm/PMN co-cultures. Sperm viability was assessed using SYBR/PI and acrosome integrity was assessed using PNA-FITC/PI by flow cytometry. The results demonstrate NETs release in native semen samples and PMN/sperm co-cultures. In addition, NETs negatively affect canine sperm function parameters. This is the first report on the ability of NETs to efficiently entrap canine spermatozoa, and to provide additional data on the adverse effects of NETs on male gametes. Therefore, NETs formation should be considered in future studies of canine reproductive failure, as these extracellular fibers and NET-derived pro-inflammatory capacities will impede proper oocyte fertilization and embryo implantation. These data will serve as a basis to explain certain reproductive failures of dogs and provide new information about triggers and molecules involved in adverse effects of NETosis for domestic pet animals.

The Biological Significance of Trogocytosis

Trogocytosis is the intercellular transfer of membrane and membrane-associated proteins between cells. Trogocytosis is an underappreciated phenomenon that has historically routinely been dismissed as an artefact. With a greater understanding of the process and the implications it has on biological systems, trogocytosis has the potential to become a paradigm changer. The presence on a cell of molecules they don't endogenously express can alter the biological activity of the cell and could also lead to the acquisition of new functions. To better appreciate this phenomenon, it is important to understand how these intercellular membrane exchanges influence the function and activity of the donor and the recipient cells. In this chapter, we will examine how the molecules acquired by trogocytosis influence the biology of a variety of systems including mammalian fertilization, treatment of hemolytic disease of the newborn, viral and parasitic infections, cancer immunotherapy, and immune modulation.

Role of the human vaginal microbiota in the regulation of inflammation and sexually transmitted infection acquisition: Contribution of the non-human primate model to a better understanding?

The human vaginal microbiota has a central role in the regulation of the female reproductive tract (FRT) inflammation. Indeed, on one hand an optimal environment leading to a protection against sexually transmitted infections (STI) is associated with a high proportion of Lactobacillus spp. (eubiosis). On the other hand, a more diverse microbiota with a high amount of non-Lactobacillus spp. (dysbiosis) is linked to a higher local inflammation and an increased STI susceptibility. The composition of the vaginal microbiota is influenced by numerous factors that may lead to a dysbiotic environment. In this review, we first discuss how the vaginal microbiota composition affects the local inflammation with a focus on the cytokine profiles, the immune cell recruitment/phenotype and a large part devoted on the interactions between the vaginal microbiota and the neutrophils. Secondly, we analyze the interplay between STI and the vaginal microbiota and describe several mechanisms of action of the vaginal microbiota. Finally, the input of the NHP model in research focusing on the FRT health including vaginal microbiota or STI acquisition/control and treatment is discussed.

Dual interleukin-17A/F deficiency protects against acute and chronic response to cigarette smoke exposure in mice

IL-17A and IL-17F are both involved in the pathogenesis of neutrophilic inflammation observed in COPD and severe asthma. To explore this, mice deficient in both Il17a and Il17f and wild type (WT) mice were exposed to cigarette smoke or environmental air for 5 to 28 days and changes in inflammatory cells in bronchoalveolar lavage (BAL) fluid were determined. We also measured the mRNA expression of keratinocyte derived chemokine (Kc), macrophage inflammatory protein-2 (Mip2), granulocyte–macrophage colony stimulating factor (Gmcsf) and matrix metalloproteinase-9 (Mmp9 ) in lung tissue after 8 days, and lung morphometric changes after 24 weeks of exposure to cigarette smoke compared to air-exposed control animals. Macrophage counts in BAL fluid initially peaked at day 8 and again on day 28, while neutrophil counts peaked between day 8 and 12 in WT mice. Mice dual deficient with Il17a and 1l17f showed similar kinetics with macrophages and neutrophils, but cell numbers at day 8 and mRNA expression of Kc, Gmcsf and Mmp9 were significantly reduced. Furthermore, airspaces in WT mice became larger after cigarette smoke exposure for 24 weeks, whereas this was not seen dual Il17a and 1l17f deficient mice. Combined Il17a and Il17f deficiency resulted in significant attenuation of neutrophilic inflammatory response and protection against structural lung changes after long term cigarette smoke exposure compared with WT mice. Dual IL-17A/F signalling plays an important role in pro-inflammatory responses associated with histological changes induced by cigarette smoke exposure.

Vaginal neutrophils eliminate sperm by trogocytosis

STUDY QUESTION

What is the vaginal polymorphonuclear (PMN) spermicidal mechanism to reduce the excess of sperm?

SUMMARY ANSWER

We show that PMNs are very efficient at killing sperm by a trogocytosis-dependent spermicidal activity independent of neutrophil extracellular traps (NETs).

WHAT IS KNOWN ALREADY

Trogocytosis has been described as an active membrane exchange between immune cells with a regulatory purpose. Recently, trogocytosis has been reported as a mechanism which PMNs use to kill tumour cells or Trichomonas vaginalis.

STUDY DESIGN, SIZE, DURATION

We used in vivo murine models and human ex vivo sperm and PMNs to investigate the early PMN-sperm response.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We set up a live/dead sperm detection system in the presence of PMNs to investigate in vivo and ex vivo PMN-spermicidal activity by confocal microscopy, flow cytometry and computer-assisted sperm analysis (SCA).

MAIN RESULTS AND THE ROLE OF CHANCE

We revealed that PMNs are highly efficient at killing sperm by way of a NETs-independent, contact-dependent and serine proteases-dependent engulfment mechanism. PMNs 'bite' sperm and quickly reduce sperm motility (within 5 min) and viability (within 20 min) after contact.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted using murine models and healthy human blood PMNs; whether it is relevant to human vaginal PMNs or to cases of infertility is unknown.

WIDER IMPLICATIONS OF THE FINDINGS

Vaginal PMNs attack and immobilize excess sperm in the vagina by trogocytosis because sperm are exogenous and may carry pathogens. Furthermore, this mechanism of sperm regulation has low mucosal impact and avoids an exacerbated inflammatory response that could lead to mucosal damage or infertility.

STUDY FUNDING/COMPETING INTEREST(S)

This work was partially supported by Ministry of Economy and Competitiveness ISCIII-FIS grants, PI16/00050, and PI19/00078, co-financed by ERDF (FEDER) Funds from the European Commission, 'A way of making Europe' and IiSGM intramural grant II-PI-MRC-2017. M.R. holds a Miguel Servet II contract (CPII14/00009). M.C.L. holds IiSGM intramural contract. There are no competing interests.

A Comprehensive Profile of Chemokine Gene Expression in the Tissues of the Female Reproductive Tract in Mice

Homeostatic leukocyte trafficking into and within the female reproductive tract (FRT) contributes to fertility and reproductive health. It is unclear how this process is regulated in the anatomically distinct reproductive tissues, or whether the genes involved are affected by cyclical changes in reproductive hormones. In tissues such as skin and intestine, mouse studies have defined evolutionarily conserved molecular mechanisms for tissue-specific homing, interstitial positioning, and leukocyte egress. Chemokine family members are invariably involved, with the chemokine expression profile of a tissue regulating leukocyte content. Reproductive tissues (ovary, vagina, cervix, uterine horn) of 8 week old virgin female C57BL/6 mice (n = 20) were collected, and expression of mRNA for leukocyte markers and chemokines conducted by qPCR. Lymphocytic and myeloid cell populations within the uterus, cervix, bone marrow and PALN from virgin C57BL/6 mice were determined by flow cytometric analysis. Variation in leukocyte content between reproductive tissues is evident, with the uterus and cervix containing complex mixtures of lymphocytes and myeloid cells. Twenty-six chemokine genes are expressed in the FRT, many by several component tissues, some preferentially by one. Most striking are Xcl1 and Ccl28, which are restricted to the uterus. Ccl20 and genes encoding CXCR2 ligands are primarily transcribed in cervix and vagina. Ovary shows the lowest expression of most chemokine genes, with the notable exception of Ccl21 and Ccl27. We also identify eight chemokines in the vagina whose expression fluctuates substantially across the oestrous cycle. These data reveal complex chemokine networks within the FRT, and provide a framework for future studies of homeostatic leukocyte trafficking into and within these tissues.Abbreviations: BM: bone marrow; DC: dendritic cell; DN: double negative; FRT: female reproductive tract; FSC: forward scatter; NK: natural killer; PALN: para-aortic lymph node; SSC: side scatter; Tregs: regulatory T cells.

Estradiol impairs epithelial CXCL1 gradient in the cervix to delay neutrophil transepithelial migration during insemination

Female reproductive mucosa must allow allogenic sperm survival whereas at the same time, avoid pathogen infection. To preserve sperm from neutrophil attack, neutrophils disappear from the vagina during the ovulatory phase (high estradiol); although the mechanisms that regulate neutrophil influx to the vagina during insemination remain controversial. We investigated the sex hormone regulation of the neutrophil migration through the cervix during insemination and revealed that ovulatory estradiol dose fades the CXCL1 epithelial expression in the ectocervix and fornix; hence, retarding neutrophil migration and retaining them in the epithelium. These mechanisms spare sperm from neutrophil attack to preserve reproduction, but might compromise immunity. However, luteal progesterone dose promotes the CXCL1 gradient expression to restore neutrophil migration, to eliminate sperm and prevent sperm associated pathogen dissemination. Surprisingly, these mechanisms are hormone dependent and independent of the insemination. Thus, sex hormones orchestrate tolerance and immunity in the vaginal lumen by regulating neutrophil transepithelial migration in the fornix and ectocervix.

Estrogen Receptor-Alpha (ESR1) Governs the Lower Female Reproductive Tract Vulnerability to Candida albicans

Estradiol-based therapies predispose women to vaginal infections. Moreover, it has long been known that neutrophils are absent from the vaginal lumen during the ovulatory phase (high estradiol). However, the mechanisms that regulate neutrophil influx to the vagina remain unknown. We investigated the neutrophil transepithelial migration (TEM) into the vaginal lumen. We revealed that estradiol reduces the CD44 and CD47 epithelial expression in the vaginal ectocervix and fornix, which retain neutrophils at the apical epithelium through the estradiol receptor-alpha. In contrast, luteal progesterone increases epithelial expression of CD44 and CD47 to promote neutrophil migration into the vaginal lumen and Candida albicans destruction. Distinctive to vaginal mucosa, neutrophil infiltration is contingent to sex hormones to prevent sperm from neutrophil attack; although it may compromise immunity during ovulation. Thus, sex hormones orchestrate tolerance and immunity in the vaginal lumen by regulating neutrophil TEM.

Intra-uterine experimental infection by Ureaplasma diversum induces TNF-α mediated womb inflammation in mice

Ureaplasma diversum is an opportunistic pathogen associated with uterine inflammation, impaired embryo implantation, infertility, abortions, premature birth of calves and neonatal pneumonia in cattle. It has been suggested that the intra-uterine infection by Ureaplasma diversum can cause vascular changes that hinder the success of pregnancy. Thus, the aim of this study was to evaluate the changes of intrauterine site of A/J mice in estrus or proestrus phase inoculated with Ureaplasma diversum. The infection was monitored at 24, 48 and 72 hours by the PCR methodology to detect the Ureaplasma in the inoculation site and the profile of circulating blood cells. Morphological changes, intensity of inflammation and the production of cytokines were compared. The infected mice showed local inflammation through the production of IFN-γ and TNF-α. Ureaplasma diversum infections in the reproductive tract of studied mice seemed to be associated with the production of pro-inflammatory cytokines in uterine parenchyma. The levels of TNF-α of infected mice were dependent on the bacterial load of inoculated Ureaplasma. Uterine experimental infections by Ureaplasma diversum have not been mentioned yet and herein we presented the first report of an intrauterine infection model in mice.

Interleukin-10 modulates pulmonary neutrophilic inflammation induced by cigarette smoke exposure

AIM OF THE STUDY

Interleukin (IL)-10 is an anti-inflammatory cytokine, but its role in cigarette smoke (CS)-induced inflammation and chronic obstructive pulmonary disease (COPD) has not been fully elucidated. The purpose of this study was to investigate the effect of IL-10 deficiency on CS-induced pulmonary inflammation in mice in vivo and in vitro.

MATERIALS AND METHODS

IL-10-deficient and wild-type control mice with a C57BL6/J genetic background were exposed to CS, and inflammatory cells in bronchoalveolar lavage fluid (BALF) and mRNA of cytokines in lung were evaluated with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

During 12 days of daily CS exposure to wild-type mice, neutrophil counts in BAL fluid and tumor necrosis factor (TNF)-α mRNA expression were increased, peaked at day 8, and then declined on day 12 when the level of IL-10 reached its peak. In IL-10-deficient mice, neutrophil recruitment and TNF-α mRNA levels induced by CS exposure were significantly greater than those in wild-type mice. Keratinocyte-derived chemokine (KC; murine ortholog of human CXCL8) and granulocyte macrophage colony-stimulating factor (GM-CSF) mRNA levels or matrix metalloproteinase(MMP)-9 protein levels were not correlated with neutrophil count.

CONCLUSIONS

IL-10 had a modulatory effect on CS-induced pulmonary neutrophilic inflammation and TNF-α expression in mice in vivo and therefore appears to be an important endogenous suppressor of airway neutrophilic inflammation.

Cervico-vaginal immunoglobulin G levels increase post-ovulation independently of neutrophils

The prevalence of sexually transmitted infections (STIs) is often higher in females than in males. Although the reproductive cycle profoundly modulates local immunity in the female reproductive tract (FRT) system, significant gaps in our knowledge of the immunobiology of the FRT still exist. An intriguing and frequently observed characteristic of the FRT is the predominant presence of immunoglobulin (Ig) G in cervico-vaginal secretions. We show here that in the mouse, IgG accumulation was enhanced approximately 5-fold post-ovulation, and was accompanied by an influx of neutrophils into the FRT. To determine whether these two events were causally related, we performed short-term neutrophil depletion experiments at individual stages throughout the estrous cycle. Our results demonstrate that neutrophils were not necessary for cycle-dependent tissue remodeling and cycle progression and that cycle-dependent IgG accumulation occurred independent of neutrophils. We thus conclude that neutrophil influx and IgG accumulation are independent events that occur in the FRT during the reproductive cycle.

Pheromone-induced cell proliferation in the murine subventricular zone

Enhancement of adult neurogenesis in female mice was previously demonstrated through exposure to soiled bedding from males, although the identity of relevant chemosignals has remained unknown. The farnesenes and SBT (2-sec-butyl-4,5-dihydrothiazole) are male murine pheromones that dominant males secrete at higher levels. Previous studies have shown that they induce oestrus in female mice. We have recently shown that these pheromones strongly increase cell proliferation in the SVZ (subventricular zone) of adult female mice. In addition, we found that a female murine pheromone, 2,5-dimethylpyrazine, facilitates similar changes in males. 2,5-dimethylpyrazine is a female pheromone that is secreted when females are housed in large groups and it was originally found to suppress oestrus in females. We found that it does not have suppressive effect on the cell proliferation in the SVZ of females. Similarly, male murine pheromones, SBT and the farnesenes, do not show a suppressive effect on the cell proliferation in the SVZ of males. Our results demonstrated that pheromonal communication between males and females has strong stimulatory effect on both the reproductive physiology and brain cell proliferation, but intrasex pheromonal exchanges do not reduce progenitor proliferation in these brain regions.

Physiology and Endocrinology Symposium: role of immune cells in the corpus luteum

The immune system is essential for optimal function of the reproductive system. The corpus luteum (CL) is an endocrine organ that secretes progesterone, which is responsible for regulating the length of the estrous cycle, and for the establishment and maintenance of pregnancy in mammals. This paper reviews literature that addresses 2 areas; i) how immune cells are recruited to the CL, and ii) how immune cells communicate with luteal cells to affect the formation, development, and regression of the CL. Immune cells, primarily recruited to the ovulatory follicle from lymphoid organs after the LH surge, facilitate ovulation and populate the developing CL. During the luteal phase, changes in the population of macrophages, eosinophils, neutrophils, and T lymphocytes occur at critical functional stages of the CL. In addition to their role in facilitating ovulation, immune cells may have an important role in luteal function. Evidence shows that cytokines secreted by immune cells modulate both luteotropic and luteolytic processes. However, the decision to pursue either function may depend on the environment provided by luteal cells. It is suggested that understanding the role immune cells play could lead to identification of new strategies to improve fertility in dairy cattle and other species.

Neutrophil NETs in reproduction: from infertility to preeclampsia and the possibility of fetal loss

The intention of this review is to provide an overview of the potential role of neutrophil extracellular traps (NETs) in mammalian reproduction. Neutrophil NETs appear to be involved in various stages of the reproductive cycle, starting with fertility and possibly ending with fetal loss. The first suggestion that NETs may play a role in pregnancy-related disorders was in preeclampsia, where vast numbers were detected in the intervillous space of affected placentae. The induction of NETosis involved an auto-inflammatory component, mediated by the increased release of placental micro-debris in preeclampsia. This report was the first indicating that NETs may be associated with a human pathology not involving infection. Subsequently, NETs have since then been implicated in bovine or equine infertility, in that semen may become entrapped in the female reproductive tract during their passage to the oocyte. In this instance interesting species-specific differences are apparent, in that equine sperm evade entrapment via expression of a DNAse-like molecule, whereas highly motile bovine sperm, once free from seminal plasma (SP) that promotes interaction with neutrophils, appear impervious to NETs entrapment. Although still in the realm of speculation it is plausible that NETs may be involved in recurrent fetal loss mediated by anti-phospholipid antibodies, or perhaps even in fetal abortion triggered by infections with microorganisms such as L. monocytogenes or B. abortus.

Beneficial lactobacilli: effects on the vaginal tract in a murine experimental model

Vaginal probiotics containing lactic acid bacteria with activity towards pathogenic microorganisms that cause urogenital tract infections have been proposed as a valid strategy for their prophylaxis and therapy. A murine experimental model was set up to evaluate the colonization capability of beneficial human lactobacilli and their effects on the mouse vaginal mucosa and innate immune cells. Five Lactobacillus strains were intravaginally inoculated into previously estrogenized BALB/c mice. The significance of the effects observed in the vaginal tract was determined by analysis of variance using the general linear model. The numbers of viable vaginal lactobacilli were significantly higher at proestrous-estrous than those at the metaestrous-diestrous phase and decreased markedly on the days after inoculation. Lactobacilli inoculation did not cause cytological or histological modifications of the murine vaginal tract. Moreover, the intravaginal administration of Lactobacillus salivarius CRL (Centro de Referencia para Lactobacilos culture collection) 1328 and Lactobacillus gasseri CRL 1263 did not affect the amounts of granulocytes and macrophages present in vaginal washings. In conclusion, the results demonstrate that vaginal lactobacilli did not produce adverse effects on the murine vaginal tract. Therefore, they could be proposed as safe probiotic candidates to promote a balanced microbiota in the urogenital tract.

Vaginal bacterial flora and cytology in proestrous bitches: role on fertility

The study of canine vaginal cytology underwent limited evolution over the years. Presence and significance of inflammatory cells in vaginal smears are little considered aspects in the bitch. Moreover, occurrence of vaginal bacteria in breeding bitches during follicular phase of the reproductive cycle, in absence of clinical signs of infection, involves the difficult question of antibiotics administration. The aim of this study was to relate findings in vaginal cytology (presence of neutrophils, lymphocytes, eosinophils, erytrocytes and bacteria) and microbial environment during proestrus with fertility outcomes (development of pregnancy, uterine infection, resorption, abortion and neonatal mortality). Bacteria sensitivity to antibiotics normally used in small animal practice was also evaluated. Bacteria isolated from vagina, in order of frequency, were Enterococcus faecalis, Streptococcus β-haemolyticus, Pasteurella multocida, E. coli, Klebsiella pneumoniae, Proteus mirabilis, E. coli haemolyticus, Arcanobacterium pyogenes, Streptococcus spp., Staphylococcus spp. and Acinetobacter spp. No mycoplasmas were observed. The present study showed that proestrous cytological aspects do not affect fertility. Eosinophils were never detected, while erythrocytes were always detected. During diestrus, E. coli was found in all pregnant bitches that developed clinical symptoms of uterine disorders (n = 3), resulting in uterine infection, resorption or abortion, but without statistical significance. Vaginal presence of Streptococcus spp. in proestrus was instead negatively associated with development of uterine infections (P = 0.005). Therefore, Streptococcus spp. could have a protective competitive role against more dangerous pathogens affecting fertility of the bitch. Among the 12 antibiotics tested, Gram-negative bacteria showed a significant sensitivity towards the amoxicillin and clavulanic acid association (P = 0.038). However, antibiotic treatment before mating, on the basis of positive culture, yet in the absence of clinical signs, seems to be unnecessary besides harmful leading to imbalance in vaginal commensal flora with adverse effects on fertility. In conclusion, vaginal bacteria, neutrophils, lymphocytes and erytrocytes should be considered as physiological aspect in the bitch during proestrus that does not require antibiotic therapy when asymptomatic.

Remodeling of the cervix and parturition in mice lacking the progesterone receptor B isoform

Withdrawal of progestational support for pregnancy is part of the final common pathways for parturition, but the role of nuclear progesterone receptor (PGR) isoforms in this process is not known. To determine if the PGR-B isoform participates in cervical remodeling at term, cervices were obtained from mice lacking PGR-B (PGR-BKO) and from wild-type (WT) controls before or after birth. PGR-BKO mice gave birth to viable pups at the same time as WT controls during the early morning of Day 19 postbreeding. Morphological analyses indicated that by the day before birth, cervices from PGR-BKO and WT mice had increased in size, with fewer cell nuclei/area as well as diminished collagen content and structure, as evidenced by optical density of picrosirius red-stained sections, compared to cervices from nonpregnant mice. Moreover, increased numbers of resident macrophages, but not neutrophils, were found in the prepartum cervix of PGR-BKO compared to nonpregnant mice, parallel to findings in WT mice. These results suggest that PGR-B does not contribute to the growth or degradation of the extracellular matrix or proinflammatory processes associated with recruitment of macrophages in the cervix leading up to birth. Rather, other receptors may contribute to the progesterone-dependent mechanism that promotes remodeling of the cervix during pregnancy and in the proinflammatory process associated with ripening before parturition.

The effect of hormone therapy and tibolone on serum CD40L and ADAM-8 in healthy post-menopausal women

BACKGROUND/AIM

The role of neutrophils and platelets in atherothrombotic disease is well established. The aim of our study was to investigate the effect of HT and tibolone on the soluble markers of neutrophil and platelet activation, "a disentigrin and metalloproteinase domain" (ADAM-8) and CD40 ligand (CD40L) respectively, in healthy post-menopausal women.

SUBJECTS AND METHODS

One hundred and six healthy post-menopausal women were randomly allocated to: estradiol plus drospirenone (E₂/DSP), E₂ hemihydrate 1 mg plus norethisterone acetate (E₂/NETA) 0.5 mg, and tibolone 2.5 mg. Serum ADAM-8 and CD40L were measured at baseline and at 6 months.

RESULTS

Baseline values of ADAM-8 and CD40L were similar between groups. No significant correlation was revealed between ADAM-8 or CD40L and parameters related to cardiovascular risk factors in each group. No significant changes were observed between baseline values and values at 6 months (E₂/DSP group: ADAM-8: 267.4±71.3 pg/ml vs 270.7±42.8 pg/ml, p=0.86, CD40L: 6.43±3.13 vs 6.79±2.70 ng/ml, p=0.67), (E₂/NETA group: ADAM-8: 308.3±64.3 vs 294.7±57.7 pg/ml, p=0.40, CD40L: 9.68±2.81 vs 8.59±5.13 ng/ml, p=0.51), (tibolone group: ADAM-8: 307.5±87.5 vs 289±48.1 pg/ml, p=0.48, CD40L: 9.46±4.30 vs 9.26±4.60 ng/ml, p=0.99).

CONCLUSIONS

Our study has not revealed an association between estrogen plus progestin treatment or tibolone on serum ADAM-8 and CD40L levels in healthy post-menopausal women. Larger prospective studies are needed to further investigate the effect of low-dose HT or tibolone on serum markers of neutrophil and platelet activation.

Sex hormone regulation of innate immunity in the female reproductive tract: the role of epithelial cells in balancing reproductive potential with protection against sexually transmitted pathogens

The immune system in the female reproductive tract (FRT) does not mount an attack against HIV or other sexually transmitted infections (STI) with a single endogenously produced microbicide or with a single arm of the immune system. Instead, the body deploys dozens of innate antimicrobials to the secretions of the female reproductive tract. Working together, these antimicrobials along with mucosal antibodies attack many different viral, bacterial and fungal targets. Within the FRT, the unique challenges of protection against sexually transmitted pathogens coupled with the need to sustain the development of an allogeneic fetus have evolved in such a way that sex hormones precisely regulate immune function to accomplish both tasks. The studies presented in this review demonstrate that estradiol and progesterone secreted during the menstrual cycle act both directly and indirectly on epithelial cells and other immune cells in the reproductive tract to modify immune function in a way that is unique to specific sites throughout the FRT. As presented in this review, studies from our laboratory and others demonstrate that the innate immune response is under hormonal control, varies with the stage of the menstrual cycle, and as such is suppressed at mid-cycle to optimize conditions for successful fertilization and pregnancy. In doing so, a window of STI vulnerability is created during which potential pathogens including HIV enter the reproductive tract to infect host targets.