Dysfunction of monocytes and dendritic cells in patients with premature ovarian failure

Immunophenotypic profiles and inflammatory markers in Premature Ovarian Insufficiency

Premature Ovarian Insufficiency (POI), also known as Premature Ovarian Failure (POF), is a heterogeneous disorder characterized by the cessation of ovarian function before age 40. Clinical symptoms include menstrual disorders: amenorrhea/oligomenorrhea or symptoms of estrogen deficiency. This review aims to provide the most important summary of the immunophenotypic profile of premature ovarian failure syndrome, along with a review of the latest reports on the usefulness of inflammatory markers. The inflammatory microenvironment in POI applies to many levels. Concomitants of autoimmune ovarian inflammation and impaired cellular immune response may be a picture of impaired regulation in autoimmune ovarian disease. The serum concentration of pro-inflammatory cytokines, like IL-6, IL-8, IL-17, tumor necrosis factor α (TNF-α), and interferon-gamma (IFN-γ), tend to increase, whereas levels of the anti-inflammatory cytokine, IL-10, tend to decrease. In our review, we focus on whether the measured immunological parameters could help in the diagnosis and prognosis of the syndrome. Among the inflammatory markers, neutrophil-to-lymphocyte ratio (NLR) is noteworthy, as it is decreased in patients with POI. It is important to stress that besides case series, we need properly powered studies with randomization to answer which treatment is effective, and how to deal with concurrent autoimmunity. In this review, we emphasize the importance of the premature ovarian failure syndrome immunoprofile for a proper understanding of the complexity of this syndrome, potential diagnostic points, and therapeutic targets.

Single-cell RNA sequencing of peripheral blood reveals immune cell dysfunction in premature ovarian insufficiency

Background

Premature ovarian insufficiency (POI) is one of the most common causes of female infertility and the etiology is highly heterogeneous. Most cases are idiopathic and the pathogenesis remains unclear. Previous studies proved that the immune system plays a crucial role in POI. However, the precise role of immune system remains unclear. This study aimed to analyze the characteristics of peripheral blood mononuclear cells (PBMC) from patients with POI by single-cell RNA sequencing (scRNA-seq) and to explore the potential involvement of immune response in idiopathic POI.

Methods

PBMC was collected from three normal subjects and three patients with POI. PBMC was subjected to scRNA-seq to identify cell clusters and differently expressed genes (DEGs). Enrichment analysis and cell-cell communication analysis were performed to explore the most active biological function in the immune cells of patients with POI.

Results

In total, 22 cell clusters and 10 cell types were identified in the two groups. Compared with normal subjects, the percentage of classical monocytes and NK cells was decreased, the abundance of plasma B cells was increased, and CD4/CD8 ratio was significantly higher in POI. Furthermore, upregulation of IGKC, IFITM1, CD69, JUND and downregulation of LYZ, GNLY, VCAN, and S100A9 were identified, which were enriched in NK cell-mediated cytotoxicity, antigen processing and presentation, and IL-17 signaling pathway. Among them, IGHM and LYZ were respectively the most significantly upregulated and downregulated genes among all cell clusters of POI. The strength of cell-cell communication differed between the healthy subjects and patients with POI, and multiple signaling pathways were assessed. The TNF pathway was found to be unique in POI with classical monocytes being the major target and source of TNF signaling.

Conclusions

Dysfunction of cellular immunity is related to idiopathic POI. Monocytes, NK cells, and B cells, and their enriched differential genes may play a role in the development of idiopathic POI. These findings provide novel mechanistic insight for understanding the pathogenesis of POI.

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.

Premature ovarian insufficiency (POI) and autoimmunity-an update appraisal

PURPOSE

Primary ovarian insufficiency (POI) represents ovarian dysfunction related to very early aging of the ovaries. While the cause of POI in a majority of clinical cases remains undefined, autoimmunity is responsible for approximately 4-30% of POI cases. In the present paper, we aim to provide a critical appraisal and update review on the role of autoimmunity in POI patients.

METHODS

A literature review was conducted for all relevant articles reporting on POI and autoimmunity. PubMed/MEDLINE and the Cochrane library were searched for the best available evidence on this topic.

RESULTS

Patients with POI and coexisting autoimmunity are indistinguishable from those with negative autoimmune screen with regard to age of onset, prevalence of primary amenorrhea, or their endocrine profiles. A specific noninvasive reliable diagnostic test for the diagnosis of an autoimmune etiology is lacking; therefore, patients should be screened for the most common autoantibodies, i.e., steroid cell antibodies, anti-ovarian antibodies, and anti-thyroid antibodies. Moreover, treatment strategies to POI infertility are lacking and controversial.

CONCLUSIONS

Nowadays, guidelines for the treatment of autoimmune POI are not available. Moreover, since diagnostic and treatment strategies to POI infertility are still lacking and controversial, further large clinical studies are needed to investigate the true impact of autoimmunity on POI and to identify the selected groups of patients who are most likely to benefit from immunossuprresive treatment.

Immunoregulation of follicular renewal, selection, POF, and menopause in vivo, vs. neo-oogenesis in vitro, POF and ovarian infertility treatment, and a clinical trial

The immune system plays an important role in the regulation of tissue homeostasis ("tissue immune physiology"). Function of distinct tissues during adulthood, including the ovary, requires (1) Renewal from stem cells, (2) Preservation of tissue-specific cells in a proper differentiated state, which differs among distinct tissues, and (3) Regulation of tissue quantity. Such morphostasis can be executed by the tissue control system, consisting of immune system-related components, vascular pericytes, and autonomic innervation. Morphostasis is established epigenetically, during morphogenetic (developmental) immune adaptation, i.e., during the critical developmental period. Subsequently, the tissues are maintained in a state of differentiation reached during the adaptation by a "stop effect" of resident and self renewing monocyte-derived cells. The later normal tissue is programmed to emerge (e.g., late emergence of ovarian granulosa cells), the earlier its function ceases. Alteration of certain tissue differentiation during the critical developmental period causes persistent alteration of that tissue function, including premature ovarian failure (POF) and primary amenorrhea. In fetal and adult human ovaries the ovarian surface epithelium cells called ovarian stem cells (OSC) are bipotent stem cells for the formation of ovarian germ and granulosa cells. Recently termed oogonial stem cells are, in reality, not stem but already germ cells which have the ability to divide. Immune system-related cells and molecules accompany asymmetric division of OSC resulting in the emergence of secondary germ cells, symmetric division, and migration of secondary germ cells, formation of new granulosa cells and fetal and adult primordial follicles (follicular renewal), and selection and growth of primary/preantral, and dominant follicles. The number of selected follicles during each ovarian cycle is determined by autonomic innervation. Morphostasis is altered with advancing age, due to degenerative changes of the immune system. This causes cessation of oocyte and follicular renewal at 38 +/-2 years of age due to the lack of formation of new granulosa cells. Oocytes in primordial follicles persisting after the end of the prime reproductive period accumulate genetic alterations resulting in an exponentially growing incidence of fetal trisomies and other genetic abnormalities with advanced maternal age. The secondary germ cells also develop in the OSC cultures derived from POF and aging ovaries. In vitro conditions are free of immune mechanisms, which prevent neo-oogenesis in vivo. Such germ cells are capable of differentiating in vitro into functional oocytes. This may provide fresh oocytes and genetically related children to women lacking the ability to produce their own follicular oocytes. Further study of "immune physiology" may help us to better understand ovarian physiology and pathology, including ovarian infertility caused by POF or by a lack of ovarian follicles with functional oocytes in aging ovaries. The observations indicating involvement of immunoregulation in physiological neo-oogenesis and follicular renewal from OSC during the fetal and prime reproductive periods are reviewed as well as immune system and age-independent neo-oogenesis and oocyte maturation in OSC cultures, perimenopausal alteration of homeostasis causing disorders of many tissues, and the first OSC culture clinical trial.

Ovarian stem cells and aging

OBJECTIVE

To review successes to date in the field of ovarian stem cell research and discuss the evidence supporting their potential to rejuvenate the follicular pool during adult life; to present factors that may contribute to their competence; and to address the question of why menopause is an inevitable outcome of advanced age if ovarian stem cells exist.

METHOD

In a review of the literature, relevant articles were identified through a PubMed literature search from inception to July 2010.

RESULTS

The current concept that mammalian ovaries possess a static ovarian reserve is at odds with the experimental results discussed in this review. Ovarian stem cells are likely to be the source of germline stem cells during fetal and adult life, due to their potential to differentiate into competent oocytes given a suitable environment.

CONCLUSIONS

Stem cells in different compartments share properties such as pluripotency, self-renewal, and diminished regenerative potential in old age. Our model of ovarian stem cell aging suggests that menopause is driven by an age-related decline in ovarian stem cell function rather than depletion of a non-renewable follicular reserve. Understanding how ovarian stem cells interact with their surrounding environment moves us a step closer to controlling the female biological clock when it might be clinically desirable.

Immune maintenance of self in morphostasis of distinct tissues, tumour growth and regenerative medicine

Morphostasis (tissue homeostasis) is a complex process consisting of three circumstances: (1) tissue renewal from stem cells, (2) preservation of tissue cells in a proper differentiated state and (3) maintenance of tissue quantity. This can be executed by a tissue control system (TCS) consisting of vascular pericytes, immune system-related components--monocyte-derived cells (MDC), T cells and immunoglobulins and autonomic innervation. Morphostasis is established epigenetically, during the critical developmental period corresponding to the morphogenetic immune adaptation. Subsequently, the tissues are maintained in a state of differentiation reached during the adaptation by a 'stop effect' of MDC influencing markers of differentiating tissue cells and presenting self-antigens to T cells. Retardation or acceleration of certain tissue differentiation during adaptation results in its persistent functional immaturity or premature ageing. The tissues being absent during adaptation, like ovarian corpus luteum, are handled as a 'graft.' Morphostasis is altered with age advancement, because of the degenerative changes of the immune system. That is why the ageing of individuals and increased incidence of neoplasia and degenerative diseases occur. Hybridization of tumour stem cells with normal tissue cells causes an augmentation of neoplasia by host pericytes and MDC stimulating a 'regeneration' of depleted functional cells. Degenerative diseases are associated with apoptosis. If we are able to change morphostasis in particular tissue, we may disrupt apoptotic process of the cell. An ability to manage the 'stop effect' of MDC may provide treatment for early post-natal tissue disorders, improve regenerative medicine and delay physical, mental and hormonal ageing.

Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine

The immune system plays an important role in immunity (immune surveillance), but also in the regulation of tissue homeostasis (immune physiology). Lessons from the female reproductive tract indicate that immune system related cells, such as intraepithelial T cells and monocyte-derived cells (MDC) in stratified epithelium, interact amongst themselves and degenerate whereas epithelial cells proliferate and differentiate. In adult ovaries, MDC and T cells are present during oocyte renewal from ovarian stem cells. Activated MDC are also associated with follicular development and atresia, and corpus luteum differentiation. Corpus luteum demise resembles rejection of a graft since it is attended by a massive influx of MDC and T cells resulting in parenchymal and vascular regression. Vascular pericytes play important roles in immune physiology, and their activities (including secretion of the Thy-1 differentiation protein) can be regulated by vascular autonomic innervation. In tumors, MDC regulate proliferation of neoplastic cells and angiogenesis. Tumor infiltrating T cells die among malignant cells. Alterations of immune physiology can result in pathology, such as autoimmune, metabolic, and degenerative diseases, but also in infertility and intrauterine growth retardation, fetal morbidity and mortality. Animal experiments indicate that modification of tissue differentiation (retardation or acceleration) during immune adaptation can cause malfunction (persistent immaturity or premature aging) of such tissue during adulthood. Thus successful stem cell therapy will depend on immune physiology in targeted tissues. From this point of view, regenerative medicine is more likely to be successful in acute rather than chronic tissue disorders.

Study origin of germ cells and formation of new primary follicles in adult human and rat ovaries

The central thesis regarding the human ovaries is that, although primordial germ cells in embryonal ovaries are of extraovarian origin, those generated during the fetal period and in postnatal life are derived from the ovarian surface epithelium (OSE) bipotent cells. With the assistance of immune system-related cells, secondary germ cells and primitive granulosa cells originate from OSE stem cells in the fetal and adult human gonads. Fetal primary follicles are formed during the second trimester of intrauterine life, prior to the end of immune adaptation, possibly to be recognized as self-structures and renewed later. With the onset of menarche, a periodical oocyte and follicular renewal emerges to replace aging primary follicles and ensure that fresh eggs for healthy babies are always available during the prime reproductive period. The periodical follicular renewal ceases between 35 and 40 yr of age, and the remaining primary follicles are utilized during the premenopausal period until exhausted. However, the persisting oocytes accumulate genetic alterations and may become unsuitable for ovulation and fertilization. The human OSE stem cells preserve the character of embryonic stem cells, and they may produce distinct cell types, including new eggs in vitro, particularly when derived from patients with premature ovarian failure or aging and postmenopausal ovaries. Our observations also indicate that there are substantial differences in follicular renewal between adult human and rat ovaries. As part of this chapter, we present in detail protocols utilized to analyze oogenesis in humans and to study interspecies differences when compared to the ovaries of rat females.

Potential new strategies for the treatment of ovarian infertility and degenerative diseases with autologous ovarian stem cells

The 50-year-old and currently prevailing view that all oocytes in adult human ovaries persist from the fetal period of life is controversial as it clashes with Darwinian evolutionary theory. Studies of oogenesis and follicular renewal in adult human ovaries, and of the role of hormonal signals and third-party cells (tissue macrophages and T cells), could all be helpful in providing better understanding of the causes of ovarian infertility, its prevention and potential therapy. In addition, the authors recently reported differentiation of distinct cell types and the production of new eggs in cultures derived from premenopausal and postmenopausal human ovaries. It is possible that fertilisation of such eggs will open up new opportunities for providing genetically related children to infertile women for whom conventional in vitro fertilisation has failed. As ovarian stem cells appear to represent a new type of totipotent adult stem cell, they could also be utilised for autologous stem cell therapy of degenerative diseases, without any involvement of allogeneic embryonic stem cells and somatic cell nuclear transfer.

Ovarian autoimmune disease and ovarian autoantibodies

Detection of specific autoantibodies remains the most practical clinical and research marker of autoimmune disease. The lack of consensus on ovary specific antibodies as a marker for ovarian autoimmunity has clinical and research consequences. The objective of this review is to summarize the evidence for ovarian autoimmunity and the detection of ovary specific autoantibodies in humans. Evidence favors the presence of an autoimmune disease of the ovary. Ovarian autoantibodies are associated primarily with premature ovarian failure (POF) and unexplained infertility. Variations in detection of ovarian autoantibodies are likely to be due to study design elements such as antibody test format, antigen preparation, and criteria for study and comparison groups. In addition, multiple targets appear to be involved in ovarian autoimmunity including ovarian cellular elements and oocyte related antigens. Many studies only assess one target antigen, leaving individuals with ovarian autoimmunity unidentified. The next most significant advance in characterizing ovarian autoimmunity will be definitive identification of the specific antigens and development of standardized tests based on use of specific antigens.

Premature ovarian failure and ovarian autoimmunity

Premature ovarian failure (POF) is defined as a syndrome characterized by menopause before the age of 40 yr. The patients suffer from anovulation and hypoestrogenism. Approximately 1% of women will experience menopause before the age of 40 yr. POF is a heterogeneous disorder with a multicausal pathogenesis involving chromosomal, genetic, enzymatic, infectious, and iatrogenic causes. There remains, however, a group of POF patients without a known etiology, the so-called "idiopathic" form. An autoimmune etiology is hypothesized for the POF cases with a concomitant Addison's disease and/or oöphoritis. It is concluded in this review that POF in association with adrenal autoimmunity and/or Addison's disease (2-10% of the idiopathic POF patients) is indeed an autoimmune disease. The following evidence warrants this view: 1) The presence of autoantibodies to steroid-producing cells in these patients; 2) The characterization of shared autoantigens between adrenal and ovarian steroid-producing cells; 3) The histological picture of the ovaries of such cases (lymphoplasmacellular infiltrate around steroid-producing cells); 4) The existence of various autoimmune animal models for this syndrome, which underlines the autoimmune nature of the disease. There is some circumstantial evidence for an autoimmune pathogenesis in idiopathic POF patients in the absence of adrenal autoimmunity or Addison's disease. Arguments in support of this are: 1) The presence of cellular immune abnormalities in this POF patient group reminiscent of endocrine autoimmune diseases such as IDDM, Graves' disease, and Addison's disease; 2) The more than normal association with IDDM and myasthenia gravis. Data on the presence of various ovarian autoantibodies and anti-receptor antibodies in these patients are, however, inconclusive and need further evaluation. A strong argument against an autoimmune pathogenesis of POF in these patients is the nearly absent histological confirmation (the presence of an oöphoritis) in these cases (< 3%). However, in animal models using ZP immunization, similar follicular depletion and fibrosis (as in the POF women) can be detected. Accepting the concept that POF is a heterogenous disorder in which some of the idiopathic forms are based on an abnormal self-recognition by the immune system will lead to new approaches in the treatment of infertility of these patients. There are already a few reports on a successful ovulation-inducing treatment of selected POF patients (those with other autoimmune phenomena) with immunomodulating therapies, such as high dosages of corticosteroids (288-292).

Cytokines in the ovary: pathophysiology and potential for pharmacological intervention

The ovary and testis are sites for interaction between the endocrine and immune system via leukocytes and their secreted products, the cytokines. There are convincing data available to show that the gonads are sites of cytokine action and production. In the ovary, cytokines and leukocytes are intimately involved in follicular development, ovulation, and luteal function. A variety of clinical situations may be due to cytokine action in the gonads, and therapeutic manipulation of the immune system may affect reproductive function.

Analysis of peripheral blood lymphocyte subsets, NK cells, and delayed type hypersensitivity skin test in patients with premature ovarian failure

PROBLEM

Premature ovarian failure (POF) probably belongs to the group of autoimmune endocrinopathies. Cell-mediated immune parameters were investigated. Sex steroids have a profound effect on the immune system. POF patients and postmenopausal control women (PM) were tested with or without estrogen substitution.

METHOD

A novel FACS analysis system (using double labeling techniques) was used in 30 patients with POF to enumerate the subjects of peripheral blood lymphocytes and NK cells. Eighteen PM women and 30 healthy men and women served as controls. We also tested the delayed type hypersensitivity skin test (DTH) toward Candida in the POF patient group to be informed on their cell-mediated immune function.

RESULTS

The numbers of blood lymphocytes, CD3+, CD4+ and CD8+T cells, were not abnormal in POF patients. However, HLA-DR+T cells were increased in POF patients and in PM women (P < 0.05). These elevated numbers were partially reversible by estrogen substitution. The number of CD19+ cells (B cells) was elevated, whereas CD3-/CD16+/CD56+ cells (NK cells) were decreased in POF patients (P < 0.05), irrespective of estrogen substitution. DTH skin tests toward 0.1% Candidin (0.1 ml intradermal injection) were negative in 11 out of 20 tested POF patients, compared to only 2 out of 10 tested controls (P < 0.05).

CONCLUSION

POF patients show numerous immune cell abnormalities. These abnormalities were only partially due to estrogen deficiency. We hypothesize that these abnormalities either lead to ovarian autoimmunity or may have direct effects on the ovarian function.