Placenta-Derived Mesenchymal Stem Cells Restore the Ovary Function in an Ovariectomized Rat Model via an Antioxidant Effect

Stem cell-based therapeutic potential in female ovarian aging and infertility

Premature ovarian insufficiency (POI) is defined as onset of menopause characterized by amenorrhea, hypergonadotropism, and hypoestrogenism, before the age of 40 years. The POI is increasing, which seriously affects the quality of patients' life. Due to its diversity of pathogenic factors, complex pathogenesis and limited treatment methods, the search for finding effective treatment of POI has become a hotspot. Stem cells are characterized by the ability of self-renewal and differentiation and play an important role in the regeneration of injured tissues, which is therapy is expected to be used in the treatment of POI. The aim of this review is to summarize the pathogenic mechanisms and the research progress of POI treatment with stem cells from different sources.

Use of placental-derived mesenchymal stem cells to restore ovarian function and metabolic profile in a rat model of the polycystic ovarian syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disturbance that affects many women worldwide and is characterized by chronic anovulation, hyperandrogenism, and ovarian dysfunction. Placenta-derived mesenchymal stem cells (PDMSCs) are derived from the placenta and have advantages over other sources of MSCs in terms of availability, safety, and immunomodulation.

MATERIALS AND METHODS

In this experimental study, twenty female Wistar rats were assigned to four groups (n = 5) including control, sham, PCOS, and PCOS+PDMSCs groups. Then, PCOS was induced in the rats through administering letrozole for 21 days. PDMSCs (1 × 106 cells) were injected through the tail vein. Fourteen days after the cell infusion, evaluation was performed on the number of healthy follicles, corpus luteum, and cystic follicles as well as the levels of testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), fasting blood glucose, fasting insulin, and insulin resistance. Moreover, the serum levels of cholesterol, triglyceride (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were measured. Liver function was also determined by the evaluation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels.

RESULTS

The number of corpus luteum and primordial, primary, secondary, and antral follicles was significantly elevated in the PCOS+PDMSCs group compared to the PCOS group. However, the number of cystic follicles significantly decreased in the PCOS+PDMSCs group. The LH and testosterone levels also decreased significantly, while FSH levels increased significantly in the PCOS+PDMSCs group. The levels of fasting blood glucose, fasting insulin, and insulin resistance notably decreased in the PCOS+PDMSCs group. Moreover, the lipid profile improved in the PCOS+PDMSCs group along with a significant decrease of cholesterol, LDL, and TG and an increase in HDL. The PCOS+PDMSCs group exhibited marked decreases in the AST and ALT levels as well.

CONCLUSION

The results of this study suggest that PDMSCs are a potential treatment option for PCOS because they can effectively restore folliculogenesis and correct hormonal imbalances, lipid profiles and liver dysfunction in a rat model of PCOS. However, further research is needed to establish the safety and effectiveness of PDMSCs for treating PCOS.

3D hUC-MSC spheroids exhibit superior resistance to autophagy and apoptosis of granulosa cells in POF rat model

In brief

This study reveals that orthotopic transplantation of 3D hUC-MSC spheroids is more effective than monolayer-cultured hUC-MSCs in improving POF and distinctly reducing oxidative stress through the paracrine effect, thereby preventing apoptosis and autophagy of GCs.

Abstract

Premature ovarian failure (POF) is a common reproductive disease in women younger than 40 years old, and studies have demonstrated that the application of human umbilical cord mesenchymal stem cells (hUC-MSCs) is a promising therapy strategy for POF. Given the previously established therapeutic advantages of 3D MSC spheroids, and to evaluate their effectiveness, both 3D hUC-MSC spheroids and monolayer-cultured hUC-MSCs were employed to treat a cyclophosphamide-induced POF rat model through orthotopic transplantation. The effects of these two forms on POF were subsequently assessed by examining apoptosis, autophagy, and oxidative damage in ovarian granulosa cells (GCs). The results indicated that hUC-MSC spheroids exhibited superior treatment effects on resisting autophagy, apoptosis, and oxidative damage in GCs compared to monolayer-cultured hUC-MSCs. To further elucidate the impact of hUC-MSC spheroids in vitro, a H2O2-induced KGN cells model was established and co-cultured with both forms of hUC-MSCs. As expected, the hUC-MSC spheroids also exhibited superior effects in resisting apoptosis and autophagy caused by oxidative damage. Therefore, this study demonstrates that 3D hUC-MSC spheroids have potential advantages in POF therapy; however, the detailed mechanisms need to be further investigated. Furthermore, this study will provide a reference for the clinical treatment strategy of POF.

Exosomes: compositions, biogenesis, and mechanisms in diabetic wound healing

Diabetic wounds are characterized by incomplete healing and delayed healing, resulting in a considerable global health care burden. Exosomes are lipid bilayer structures secreted by nearly all cells and express characteristic conserved proteins and parent cell-associated proteins. Exosomes harbor a diverse range of biologically active macromolecules and small molecules that can act as messengers between different cells, triggering functional changes in recipient cells and thus endowing the ability to cure various diseases, including diabetic wounds. Exosomes accelerate diabetic wound healing by regulating cellular function, inhibiting oxidative stress damage, suppressing the inflammatory response, promoting vascular regeneration, accelerating epithelial regeneration, facilitating collagen remodeling, and reducing scarring. Exosomes from different tissues or cells potentially possess functions of varying levels and can promote wound healing. For example, mesenchymal stem cell-derived exosomes (MSC-exos) have favorable potential in the field of healing due to their superior stability, permeability, biocompatibility, and immunomodulatory properties. Exosomes, which are derived from skin cellular components, can modulate inflammation and promote the regeneration of key skin cells, which in turn promotes skin healing. Therefore, this review mainly emphasizes the roles and mechanisms of exosomes from different sources, represented by MSCs and skin sources, in improving diabetic wound healing. A deeper understanding of therapeutic exosomes will yield promising candidates and perspectives for diabetic wound healing management.

Exosomes as Theranostic Agents in Reproduction System

Exosomes (Exos), belonging to extracellular vesicles, are cell-derived nano-sized vesicles with the potential to carry different kinds of biological molecules. Many studies have proved the impacts of exosomal cargo on several biological processes in female and male reproductive systems. It is also hypothesized that changes in exosomal cargo are integral to the promotion of certain pathological conditions, thus Exos can be used as valid biomarkers for the diagnosis of infertility and other abnormal conditions. Here, efforts are made to collect some recent data related to the physiological significance of Exos in the reproductive system, and their potential therapeutic effects. It is anticipated that the current review article will lay the groundwork for elucidating the source and mechanisms by which Exos control the reproductive system additionally supplying fresh methods and concepts for the detection and treatment of disorders associated with fertility for future studies.

Protective effect of Luffa cylindrica fermentation liquid on cyclophosphamide-induced premature ovarian failure in female mice by attenuating oxidative stress, inflammation and apoptosis

Premature ovarian failure (POF) is a leading cause of women's infertility without effective treatment. The purpose of this study was to investigate the protective effects of Luffa cylindrica fermentation liquid (LF) on cyclophosphamide (CTX) -induced POF in mice and to preliminarily investigate the underlying mechanisms. Thirty-two Balb/c mice were divided into four groups randomly. One group served as the control, while the other three received CTX injections to establish POF models. A 14-day gavage of either 5 or 10 μL/g LF was administered to two LF pretreatment groups. To analyze the effects of LF, the ovarian index, follicle number, the levels of serum sex hormones, superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), inflammatory factors, and apoptosis of the ovarian cells were measured. The effects of LF pretreatment on the expression of TLR4/NF-κB and apoptosis pathways were also evaluated. We found that LF pretreatment increased the ovarian index and the number of primordial and antral follicles while decreasing those of atretic follicles. LF pretreatment also increased the serum levels of estradiol (E2) and anti-Müllerian hormone (AMH), while decreasing those of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Furthermore, LF pretreatment increased the levels of SOD and GSH in the ovaries, while decreasing those of MDA, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). LF administration reduced the amount of TUNEL+ ovarian cells and the levels of TLR4 and NF-κB P65 protein expression. In conclusion, LF has antioxidant, anti-inflammatory as well as anti-apoptotic effects against CTX-induced POF, and the inhibition of TLR4/NF-κB and apoptosis pathways may be involved in its mechanisms.

Protective role of stem cells in POI: Current status and mechanism of action, a review article

Premature ovarian insufficiency (POI) has far-reaching consequences on women's life quality. Due to the lack of full recognition of the etiology and complexity of this disease, there is no appropriate treatment for infected patients. Recently, stem cell therapy has attracted the attention of regenerative medicine scholars and offered promising outcomes for POI patients. Several kinds of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) have been used for the treatment of ovarian diseases. However, their potential protective mechanisms are still unknown. Undoubtedly, a better understanding of the therapeutic molecular and cellular mechanisms of stem cells will address uncover strategies to increase their clinical application for multiple disorders such as POI. This paper describes a detailed account of the potential properties of different types of stem cells and provides a comprehensive review of their protective mechanisms, particularly MSC, in POI disorder. In addition, ongoing challenges and several strategies to improve the efficacy of MSC in clinical use are addressed. Therefore, this review will provide proof-of-concept for further clinical application of stem cells in POI.

Premature ovarian insufficiency: a review on the role of tobacco smoke, its clinical harm, and treatment

Premature ovarian insufficiency (POI) is a condition in which the quantity of follicles and the quality of oocytes gradually decrease. This results in an estrogen secretion disorder and abnormal follicle development, which can lead to related diseases, early onset of menopause, sexual dysfunction, and an increased risk of cardiovascular issues, osteoporosis, and depression, among others. This disease significantly impacts the physical and mental health and overall quality of life of affected women. Factors such as genetic abnormalities, oophorectomy, radiotherapy for malignancy, idiopathic conditions, and an unhealthy lifestyle, including smoking, can accelerate the depletion of the follicular pool and the onset of menopause. Extensive research has been conducted on the detrimental effects of tobacco smoke on the ovaries. This article aims to review the advancements in understanding the impact of tobacco smoke on POI, both in vivo and in vitro. Furthermore, we explore the potential adverse effects of common toxicants found in tobacco smoke, such as polycyclic aromatic hydrocarbons (PAHs), heavy metals like cadmium, alkaloids like nicotine and its major metabolite cotinine, benzo[a]pyrene, and aromatic amines. In addition to discussing the toxicants, this article also reviews the complications associated with POI and the current state of research and application of treatment methods. These findings will contribute to the development of more precise treatments for POI, offering theoretical support for enhancing the long-term quality of life for women affected by this condition.

Stem-Cell-Derived Extracellular Vesicles: Unlocking New Possibilities for Treating Diminished Ovarian Reserve and Premature Ovarian Insufficiency

Despite advancements in assisted reproductive technology (ART), achieving successful pregnancy rates remains challenging. Diminished ovarian reserve and premature ovarian insufficiency hinder IVF success-about 20% of in vitro fertilization (IVF) patients face a poor prognosis due to a low response, leading to higher cancellations and reduced birth rates. In an attempt to address the issue of premature ovarian insufficiency (POI), we conducted systematic PubMed and Web of Science research, using keywords "stem cells", "extracellular vesicles", "premature ovarian insufficiency", "diminished ovarian reserve" and "exosomes". Amid the complex ovarian dynamics and challenges like POI, stem cell therapy and particularly the use of extracellular vesicles (EVs), a great potential is shown. EVs trigger paracrine mechanisms via microRNAs and bioactive molecules, suppressing apoptosis, stimulating angiogenesis and activating latent regenerative potential. Key microRNAs influence estrogen secretion, proliferation and apoptosis resistance. Extracellular vesicles present a lot of possibilities for treating infertility, and understanding their molecular mechanisms is crucial for maximizing EVs' therapeutic potential in addressing ovarian disorders and promoting reproductive health.

Increased IGFBP2 Levels by Placenta-Derived Mesenchymal Stem Cells Enhance Glucose Metabolism in a TAA-Injured Rat Model via AMPK Signaling Pathway

The insulin resistance caused by impaired glucose metabolism induces ovarian dysfunction due to the central importance of glucose as a source of energy. However, the research on glucose metabolism in the ovaries is still lacking. The objectives of this study were to analyze the effect of PD-MSCs on glucose metabolism through IGFBP2-AMPK signaling and to investigate the correlation between glucose metabolism and ovarian function. Thioacetamide (TAA) was used to construct a rat injury model. PD-MSCs were transplanted into the tail vein (2 × 106) 8 weeks after the experiment started. The expression of the IGFBP2 gene and glucose metabolism factors (e.g., AMPK, GLUT4) was significantly increased in the PD-MSC group compared to the nontransplantation (NTx) group (* p < 0.05). The levels of follicular development markers and the sex hormones AMH, FSH, and E2 were also higher than those in the TAA group. Using ex vivo cocultivation, the mRNA and protein expression of IGFBP2, AMPK, and GLUT4 were significantly increased in the cocultivation with the PD-MSCs group and the recombinant protein-treated group (* p < 0.05). These findings suggest that the increased IGFBP2 levels by PD-MSCs play an important role in glucose metabolism and ovarian function through the IGFBP2-AMPK signaling pathway.

Menstrual blood-derived endometrial stem cell, a unique and promising alternative in the stem cell-based therapy for chemotherapy-induced premature ovarian insufficiency

Chemotherapy can cause ovarian dysfunction and infertility since the ovary is extremely sensitive to chemotherapeutic drugs. Apart from the indispensable role of the ovary in the overall hormonal milieu, ovarian dysfunction also affects many other organ systems and functions including sexuality, bones, the cardiovascular system, and neurocognitive function. Although conventional hormone replacement therapy can partly relieve the adverse symptoms of premature ovarian insufficiency (POI), the treatment cannot fundamentally prevent deterioration of POI. Therefore, effective treatments to improve chemotherapy-induced POI are urgently needed, especially for patients desiring fertility preservation. Recently, mesenchymal stem cell (MSC)-based therapies have resulted in promising improvements in chemotherapy-induced ovary dysfunction by enhancing the anti-apoptotic capacity of ovarian cells, preventing ovarian follicular atresia, promoting angiogenesis and improving injured ovarian structure and the pregnancy rate. These improvements are mainly attributed to MSC-derived biological factors, functional RNAs, and even mitochondria, which are directly secreted or indirectly translocated with extracellular vesicles (microvesicles and exosomes) to repair ovarian dysfunction. Additionally, as a novel source of MSCs, menstrual blood-derived endometrial stem cells (MenSCs) have exhibited promising therapeutic effects in various diseases due to their comprehensive advantages, such as periodic and non-invasive sample collection, abundant sources, regular donation and autologous transplantation. Therefore, this review summarizes the efficacy of MSCs transplantation in improving chemotherapy-induced POI and analyzes the underlying mechanism, and further discusses the benefit and existing challenges in promoting the clinical application of MenSCs in chemotherapy-induced POI.

Engineered extracellular vesicles in female reproductive disorders

Biologically active and nanoscale extracellular vesicles (EVs) participate in a variety of cellular physiological and pathological processes in a cell-free manner. Unlike cells, EVs not only do not cause acute immune rejection, but are much smaller and have a low risk of tumorigenicity or embolization. Because of their unique advantages, EVs show promise in applications in the diagnosis and treatment of reproductive disorders. As research broadens, engineering strategies for EVs have been developed, and engineering strategies for EVs have substantially improved their application potential while circumventing the defects of natural EVs, driving EVs toward clinical applications. In this paper, we will review the engineering strategies of EVs, as well as their regulatory effects and mechanisms on reproductive disorders (including premature ovarian insufficiency (POI), polycystic ovarian syndrome (PCOS), recurrent spontaneous abortion (RSA), intrauterine adhesion (IUA), and endometriosis (EMS)) and their application prospects. This work provides new ideas for the treatment of female reproductive disorders by engineering EVs.

The Role of Advanced Parental Age in Reproductive Genetics

The increase of parental reproductive age is a worldwide trend in modern society in recent decades. In general, older parents have a significant impact on reproductive genetics and the health of offspring. In particular, advanced parental age contributes to the increase in the risk of adverse neurodevelopmental outcomes in offspring. However, it is currently under debate how and to what extent the health of future generations was affected by the parental age. In this review, we aimed to (i) provide an overview of the effects of age on the fertility and biology of the reproductive organs of the parents, (ii) highlight the candidate biological mechanisms underlying reproductive genetic alterations, and (iii) discuss the relevance of the effect of parental age on offspring between animal experiment and clinical observation. In addition, we think that the impact of environmental factors on cognitive and emotional development of older offspring will be an interesting direction.

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) alleviate excessive autophagy of ovarian granular cells through VEGFA/PI3K/AKT/mTOR pathway in premature ovarian failure rat model

BACKGROUND

Premature ovarian failure (POF) is one of the leading causes of female infertility and is accompanied by abnormal endocrine, seriously affecting female quality of life. Previous studies have demonstrated that mesenchymal stem cells (MSCs) transplantation is a promising therapeutic strategy for POF. However, the mechanism remains obscure. This study aims to investigate the therapeutic effect of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) on ovarian function in the POF rat model and explore the underlying mechanisms.

METHODS

The ovarian function was evaluated by ovarian morphology, histology, estrous cycle, hormone levels (AMH, E2, FSH, and LH), and fertility ability to investigate the effect of hUC-MSCs on the POF rats model. The cytokines levels were assayed in serum using protein array to explore the mechanisms of hUC-MSCs therapy for POF. The excessive autophagy levels were evaluated using a co-culture system of 3D MSCs spheroids with human ovarian granulosa cell line (KGN) or primary ovarian granulosa cells (GCs) to understand the paracrine effect of hUC-MSCs on GCs. The related proteins expression of autophagy and PI3K/AKT/mTOR pathway was detected using Western Blotting and/or in various inhibitors supplement to further demonstrate that vascular endothelial growth factor A (VEGFA) secreted by hUC-MSCs can alleviate excessive autophagy of ovarian GCs via PI3K/AKT/mTOR signaling pathway. The ovarian culture model in vitro was applied to confirm the mechanism.

RESULTS

The ovarian function of POF and the excessive autophagy of ovarian GCs were restored after hUC-MSCs transplantation. The protein array result demonstrated that VEGF and PI3K/AKT might improve ovarian function. in vitro experiments demonstrated that VEGFA secreted by hUC-MSCs could decrease oxidative stress and inhibit excessive autophagy of ovarian GCs via PI3K/AKT/mTOR pathway. The ovarian culture model results confirmed this mechanism in vitro.

CONCLUSION

The hUC-MSCs can alleviate excessive autophagy of ovarian GCs via paracrine VEGFA and regulate the PI3K/AKT/mTOR signaling pathway, thereby improving the ovarian function of POF.

Premature ovarian insufficiency: a review on the role of oxidative stress and the application of antioxidants

Normal levels of reactive oxygen species (ROS) play an important role in regulating follicular growth, angiogenesis and sex hormone synthesis in ovarian tissue. When the balance between ROS and antioxidants is disrupted, however, it can cause serious consequences of oxidative stress (OS), and the quantity and quality of oocytes will decline. Therefore, this review discusses the interrelationship between OS and premature ovarian insufficiency (POI), the potential mechanisms and the methods by which antioxidants can improve POI through controlling the level of OS. We found that OS can mediate changes in genetic materials, signal pathways, transcription factors and ovarian microenvironment, resulting in abnormal apoptosis of ovarian granulosa cells (GCs) and abnormal meiosis as well as decreased mitochondrial Deoxyribonucleic Acid(mtDNA) and other changes, thus accelerating the process of ovarian aging. However, antioxidants, mesenchymal stem cells (MSCs), biological enzymes and other antioxidants can delay the disease process of POI by reducing the ROS level in vivo.

G-CSF-mobilized peripheral blood mononuclear cells combined with platelet-rich plasma restored the ovarian function of aged rats

BACKGROUND

Regenerative medicine with peripheral blood mononuclear cell (PBMC) transplantation sheds light on the issue of premature ovarian insufficiency (POI). However, the efficiency of PBMC treatment in natural ovarian aging (NOA) remains unclear.

METHODS

Thirteen-month-old female Sprague-Dawley (SD) rats were used to verify the NOA model. Seventy-two NOA rats were randomly divided into three groups: the NOA control group, PBMC group, and PBMC+platelet-rich plasma (PRP) group. PBMCs and PRP were transplanted by intraovarian injection. The effects on ovarian function and fertility were measured after transplantation.

RESULTS

Transplantation of PBMCs could restore the normal estrous cycle, consistent with the recovery of serum sex hormone levels, increased follicle numbers at all stages, and restoration of fertility by facilitating pregnancy and live birth. Moreover, when combined with PRP injection, these effects were more significant. The male-specific SRY gene was detected in the ovary at all four time points, suggesting that PBMCs continuously survived and functioned in NOA rats. In addition, after PBMC treatment, the expression of angiogenesis-related and glycolysis-related markers in the ovaries was upregulated, which indicated that these effects were associated with angiogenesis and glycolysis.

CONCLUSIONS

PBMC transplantation restores the ovarian functions and fertility of NOA rats, and PRP could enhance the efficiency. Increased ovarian vascularization, follicle production, and glycolysis are likely the major mechanisms.

Comparison of the therapeutic effects between stem cells and exosomes in primary ovarian insufficiency: as promising as cells but different persistency and dosage

BACKGROUND

Primary ovarian insufficiency (POI) refers to the loss of ovarian function under the age of 40 and results in amenorrhea and infertility. Our previous studies have shown that transplantation of mesenchymal stem cells (MSCs) and MSC-derived exosomes in chemotherapy-induced POI mouse ovaries can reverse the POI and eventually achieve pregnancy. Based on our recent studies, MSC-derived exosomes have almost equal therapeutic potentials as transplanted MSCs. However, it is still unclear whether exosomes can completely replace MSCs in POI treatment. For the reliable application of cell-free treatment for POI patients using exosomes, there is a need to understand whether there is any outcome and effectiveness difference between MSC and MSC-derived exosome treatment.

METHODS

Comparing the therapeutic effect of intravenous injection using MSCs and equal amounts of exosomes in a POI mouse model will reveal the difference between the two therapeutic resources. In this study, we induced POI in C57/BL6 mice by chemotherapy (CXT) using a standard protocol. We then injected four different doses of MSCs or equal amounts of commercialized MSC-derived exosomes by retro-orbital injection post-CXT.

RESULT

After MSC/exosome treatment, tissue and serum samples were harvested to analyze molecular changes after treatment, while other mice in parallel experiments underwent breeding experiments to compare the restoration of fertility. Both the MSC- and exosome-treated groups had a restored estrous cycle and serum hormone levels compared to untreated POI mice. The pregnancy rate in the MSC-treated group was 60-100% after treatment, while the pregnancy rate in the exosome-treated group was 30-50% after treatment. Interestingly, in terms of long-term effects, MSC-treated mice still showed a 60-80% pregnancy rate in the second round of breeding, while the exosome-treated group became infertile again in the second round of breeding.

CONCLUSIONS

Although there were some differences in the efficacy between MSC treatment and exosome treatment, both treatments were able to achieve pregnancy in the POI mouse model. In conclusion, we report that MSC-derived exosomes are a promising therapeutic option to restore ovarian function in POI conditions similar to treatment with MSCs.

Multipotent fetal stem cells in reproductive biology research

Due to the limited accessibility of the in vivo situation, the scarcity of the human tissue, legal constraints, and ethical considerations, the underlying molecular mechanisms of disorders, such as preeclampsia, the pathological consequences of fetomaternal microchimerism, or infertility, are still not fully understood. And although substantial progress has already been made, the therapeutic strategies for reproductive system diseases are still facing limitations. In the recent years, it became more and more evident that stem cells are powerful tools for basic research in human reproduction and stem cell-based approaches moved into the center of endeavors to establish new clinical concepts. Multipotent fetal stem cells derived from the amniotic fluid, amniotic membrane, chorion leave, Wharton´s jelly, or placenta came to the fore because they are easy to acquire, are not associated with ethical concerns or covered by strict legal restrictions, and can be banked for autologous utilization later in life. Compared to adult stem cells, they exhibit a significantly higher differentiation potential and are much easier to propagate in vitro. Compared to pluripotent stem cells, they harbor less mutations, are not tumorigenic, and exhibit low immunogenicity. Studies on multipotent fetal stem cells can be invaluable to gain knowledge on the development of dysfunctional fetal cell types, to characterize the fetal stem cells migrating into the body of a pregnant woman in the context of fetomaternal microchimerism, and to obtain a more comprehensive picture of germ cell development in the course of in vitro differentiation experiments. The in vivo transplantation of fetal stem cells or their paracrine factors can mediate therapeutic effects in preeclampsia and can restore reproductive organ functions. Together with the use of fetal stem cell-derived gametes, such strategies could once help individuals, who do not develop functional gametes, to conceive genetically related children. Although there is still a long way to go, these developments regarding the usage of multipotent fetal stem cells in the clinic should continuously be accompanied by a wide and detailed ethical discussion.

Reactive oxygen species and ovarian diseases: Antioxidant strategies

Reactive oxygen species (ROS) are mainly produced in mitochondria and are involved in various physiological activities of the ovary through signaling and are critical for regulating the ovarian cycle. Notably, the imbalance between ROS generation and the antioxidant defense system contributes to the development of ovarian diseases. These contradictory effects have critical implications for potential antioxidant strategies that aim to scavenge excessive ROS. However, much remains to be learned about how ROS causes various ovarian diseases to the application of antioxidant therapy for ovarian diseases. Here, we review the mechanisms of ROS generation and maintenance of homeostasis in the ovary and its associated physiological effects. Additionally, we have highlighted the pathological mechanisms of ROS in ovarian diseases and potential antioxidant strategies for treatment.

Female Reproductive Aging and Oxidative Stress: Mesenchymal Stem Cell Conditioned Medium as a Promising Antioxidant

The recent tendency to delay pregnancy has increased the incidence of age-related infertility, as female reproductive competence decreases with aging. Along with aging, a lowered capacity of antioxidant defense causes a loss of normal function in the ovaries and uterus due to oxidative damage. Therefore, advancements have been made in assisted reproduction to resolve infertility caused by reproductive aging and oxidative stress, following an emphasis on their use. The application of mesenchymal stem cells (MSCs) with intensive antioxidative properties has been extensively validated as a regenerative therapy, and proceeding from original cell therapy, the therapeutic effects of stem cell conditioned medium (CM) containing paracrine factors secreted during cell culture have been reported to be as effective as that of direct treatment of source cells. In this review, we summarized the current understanding of female reproductive aging and oxidative stress and present MSC-CM, which could be developed as a promising antioxidant intervention for assisted reproductive technology.

Can a Large Number of Transplanted Mesenchymal Stem Cells Have an Optimal Therapeutic Effect on Improving Ovarian Function?

Mesenchymal stem cells (MSCs) are next-generation treatment in degenerative diseases. For the application of mesenchymal stem cell therapy to degenerative disease, transplantation conditions (e.g., optimized dose, delivery route and regenerating efficacy) should be considered. Recently, researchers have studied the mode of action of MSC in the treatment of ovarian degenerative disease. However, the evidence for the optimal number of cells for the developing stem cell therapeutics is insufficient. The objective of this study was to evaluate the efficacy in ovarian dysfunction, depends on cell dose. By intraovarian transplantation of low (1 × 105) and high (5 × 105) doses of placenta-derived mesenchymal stem cells (PD-MSCs) into thioacetamide (TAA)-injured rats, we compared the levels of apoptosis and oxidative stress that depend on different cell doses. Apoptosis and oxidative stress were significantly decreased in the transplanted (Tx) group compared to the non-transplanted (NTx) group in ovarian tissues from TAA-injured rats (* p < 0.05). In addition, we confirmed that follicular development was significantly increased in the Tx groups compared to the NTx group (* p < 0.05). However, there were no significant differences in the apoptosis, antioxidant or follicular development of injured ovarian tissues between the low and high doses PD-MSCs group. These findings provide new insights into the understanding and evidence obtained from clinical trials for stem cell therapy in reproductive systems.

Cell-Based Therapy Approaches in Treatment of Non-obstructive Azoospermia

The rate of infertility has globally increased in recent years for a variety of reasons. One of the main causes of infertility in men is azoospermia that is defined by the absence of sperm in the ejaculate and classified into two categories: obstructive azoospermia and non-obstructive azoospermia. In non-obstructive azoospermia, genital ducts are not obstructed, but the testicles do not produce sperm at all, due to various reasons. Non-obstructive azoospermia in most cases has no therapeutic options other than assisted reproductive techniques, which in most cases require sperm donors. Here we discuss cell-based therapy approaches to restore fertility in men with non-obstructive azoospermia including cell-based therapies of non-obstructive azoospermia using regenerative medicine and cell-based therapies of non-obstructive azoospermia by paracrine and anti-inflammatory pathway, technical and ethical challenges for using different cell sources and alternative options will be described, and then the more effectual approaches will be mentioned as future trends.

Bone marrow mesenchymal stem cells in premature ovarian failure: Mechanisms and prospects

Premature ovarian failure (POF) is a common female reproductive disorder and characterized by menopause, increased gonadotropin levels and estrogen deficiency before the age of 40 years old. The etiologies and pathogenesis of POF are not fully clear. At present, hormone replacement therapy (HRT) is the main treatment options for POF. It helps to ameliorate perimenopausal symptoms and related health risks, but can't restore ovarian function and fertility fundamentally. With the development of regenerative medicine, bone marrow mesenchymal stem cells (BMSCs) have shown great potential for the recovery of ovarian function and fertility based on the advantages of abundant sources, high capacity for self-renewal and differentiation, low immunogenicity and less ethical considerations. This systematic review aims to summarize the possible therapeutic mechanisms of BMSCs for POF. A detailed search strategy of preclinical studies and clinical trials on BMSCs and POF was performed on PubMed, MEDLINE, Web of Science and Embase database. A total of 21 studies were included in this review. Although the standardization of BMSCs need more explorations, there is no doubt that BMSCs transplantation may represent a prospective therapy for POF. It is hope to provide a theoretical basis for further research and treatment for POF.

The role of oxidative stress in ovarian aging: a review

Ovarian aging refers to the process by which ovarian function declines until eventual failure. The pathogenesis of ovarian aging is complex and diverse; oxidative stress (OS) is considered to be a key factor. This review focuses on the fact that OS status accelerates the ovarian aging process by promoting apoptosis, inflammation, mitochondrial damage, telomere shortening and biomacromolecular damage. Current evidence suggests that aging, smoking, high-sugar diets, pressure, superovulation, chemotherapeutic agents and industrial pollutants can be factors that accelerate ovarian aging by exacerbating OS status. In addition, we review the role of nuclear factor E2-related factor 2 (Nrf2), Sirtuin (Sirt), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), Forkhead box O (FoxO) and Klotho signaling pathways during the process of ovarian aging. We also explore the role of antioxidant therapies such as melatonin, vitamins, stem cell therapies, antioxidant monomers and Traditional Chinese Medicine (TCM), and investigate the roles of these supplements with respect to the reduction of OS and the improvement of ovarian function. This review provides a rationale for antioxidant therapy to improve ovarian aging.

microRNA-130b-3p delivery by mesenchymal stem cells-derived exosomes confers protection on acute lung injury

OBJECTIVE

Researchers have investigated miR-130b-3p in lung disease pathology, such as lung fibrosis. The present study was performed to elucidate the miR-130b-3p-involved mechanism in acute lung injury (ALI) through delivery by mesenchymal stem cells-derived exosomes (MSCs-Exo).

METHODS

ALI mouse models were induced via intratracheal administration of lipopolysaccharide (LPS) and treated with MSCs-Exo. Lung dry-wet (W/D) ratio, inflammatory factors in the bronchoalveolar lavage fluid, pathological damage and apoptosis in the lung tissues were analyzed. Expression levels of miR-130b-3p and TGFBR1 were measured in the mouse lung tissues, and the interaction between miR-130b-3p and TGFBR1 was studied.

RESULTS

MSCs-Exo relieved LPS-induced ALI in mice by reducing lung W/D ratio and inflammatory response, and attenuating lung tissue pathological damage and reducing the alveolar cell apoptosis. miR-130b-3p delivery by MSCs-Exo reduced LPS-induced ALI in mice. TGFBR1 was determined to be a downstream target gene of miR-130b-3p. Inhibition of TGFBR1 could remit LPS-induced ALI in mice. The protection mediated by MSCs-Exo carrying miR-130b-3p could be rescued by elevating TGFBR1 expression.

CONCLUSION

miR-130b-3p delivery by MSCs-Exo confers protection on ALI in mice via the downregulation of TGFBR1.

Biological mechanisms and applied prospects of mesenchymal stem cells in premature ovarian failure

Premature ovarian failure (POF), also known as primary ovarian insufficiency (POI), refers to the loss of ovarian function in women after puberty and before the age of 40 characterized by high serum gonadotropins and low estrogen, irregular menstruation, amenorrhea, and decreased fertility. However, the specific pathogenesis of POF is unexplained, and there is no effective therapy for its damaged ovarian tissue structure and reduced reserve function. Mesenchymal stem cells (MSCs), with multidirectional differentiation potential and self-renewal ability, as well as the cytokines and exosomes they secrete, have been studied and tested to play an active therapeutic role in a variety of degenerative pathologies, and MSCs are the most widely used stem cells in regenerative medicine. MSCs can reverse POI and enhance ovarian reserve function through differentiation into granulosa cells (GCs), immune regulation, secretion of cytokines and other nutritional factors, reduction of GCs apoptosis, and promotion of GCs regeneration. Many studies have proved that MSCs may have a restorative effect on the structure and fertility of injured ovarian tissues and turn to be a useful clinical approach to the treatment of patients with POF in recent years. We intend to use MSCs-based therapy to completely reverse POI in the future.

Therapeutic options for premature ovarian insufficiency: an updated review

Primary ovarian insufficiency (POI) is a rare gynecological condition. This disease causes menstrual disturbances, infertility, and various health problems. Historically, hormone replacement therapy is the first-line treatment for this disorder. Women diagnosed with POI are left with limited therapeutic options. In order to remedy this situation, a new generation of therapeutic approaches, such as in vitro activation, mitochondrial activation technique, stem cell and exosomes therapy, biomaterials strategies, and platelet-rich plasma intra-ovarian infusion, is being developed. However, these emerging therapies are yet in the experimental stage and require precise design components to accelerate their conversion into clinical treatments. Thus, each medical practitioner bears responsibility for selecting suitable therapies for individual patients. In this article, we provide a timely analysis of the therapeutic strategies that are available for POI patients and discuss the prospects of POI therapy.

Application of Perinatal Derivatives in Ovarian Diseases

Reproductive diseases could lead to infertility and have implications for overall health, most importantly due to psychological, medical and socio-economic consequences for individuals and society. Furthermore, economical losses also occur in animal husbandry. In both human and veterinary medicine, hormonal and surgical treatments, as well as assisted reproductive technologies are used to cure reproductive disorders, however they do not improve fertility. With ovarian disorders being the main reproductive pathology in human and bovine, over the past 2 decades research has approached regenerative medicine in animal model to restore normal function. Ovarian pathologies are characterized by granulosa cell and oocyte apoptosis, follicular atresia, decrease in oocyte quality and embryonic development potential, oxidative stress and mitochondrial abnormalities, ultimately leading to a decrease in fertility. At current, application of mesenchymal stromal cells or derivatives thereof represents a valid strategy for regenerative purposes. Considering their paracrine/autocrine mode of actions that are able to regenerate injured tissues, trophic support, preventing apoptosis and fibrosis, promoting angiogenesis, stimulating the function and differentiation of endogenous stem cells and even reducing the immune response, are all important players in their future therapeutic success. Nevertheless, obtaining mesenchymal stromal cells (MSC) from adult tissues requires invasive procedures and implicates decreased cell proliferation and a reduced differentiation capacity with age. Alternatively, the use of embryonic stem cells as source of cellular therapeutic encountered several ethical concerns, as well as the risk of teratoma formation. Therefore, several studies have recently focussed on perinatal derivatives (PnD) that can be collected non-invasively and, most importantly, display similar characteristics in terms of regenerating-inducing properties, immune-modulating properties and hypo-immunogenicity. This review will provide an overview of the current knowledge and future perspectives of PnD application in the treatment of ovarian hypofunction.

Metabolic Rewiring by Human Placenta-Derived Mesenchymal Stem Cell Therapy Promotes Rejuvenation in Aged Female Rats

Aging is a degenerative process involving cell function deterioration, leading to altered metabolic pathways, increased metabolite diversity, and dysregulated metabolism. Previously, we reported that human placenta-derived mesenchymal stem cells (hPD-MSCs) have therapeutic effects on ovarian aging. This study aimed to identify hPD-MSC therapy-induced responses at the metabolite and protein levels and serum biomarker(s) of aging and/or rejuvenation. We observed weight loss after hPD-MSC therapy. Importantly, insulin-like growth factor-I (IGF-I), known prolongs healthy life spans, were markedly elevated in serum. Capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF/MS) analysis identified 176 metabolites, among which the levels of 3-hydroxybutyric acid, glycocholic acid, and taurine, which are associated with health and longevity, were enhanced after hPD-MSC stimulation. Furthermore, after hPD-MSC therapy, the levels of vitamin B6 and its metabolite pyridoxal 5′-phosphate were markedly increased in the serum and liver, respectively. Interestingly, hPD-MSC therapy promoted serotonin production due to increased vitamin B6 metabolism rates. Increased liver serotonin levels after multiple-injection therapy altered the expression of mRNAs and proteins associated with hepatocyte proliferation and mitochondrial biogenesis. Changes in metabolites in circulation after hPD-MSC therapy can be used to identify biomarker(s) of aging and/or rejuvenation. In addition, serotonin is a valuable therapeutic target for reversing aging-associated liver degeneration.

The Role of Stem Cells and Their Derived Extracellular Vesicles in Restoring Female and Male Fertility

Infertility is a globally recognized issue caused by different reproductive disorders. To date, various therapeutic approaches to restore fertility have been attempted including etiology-specific medication, hormonal therapies, surgical excisions, and assisted reproductive technologies. Although these approaches produce results, however, fertility restoration is not achieved in all cases. Advances in using stem cell (SC) therapy hold a great promise for treating infertile patients due to their abilities to self-renew, differentiate, and produce different paracrine factors to regenerate the damaged or injured cells and replenish the affected germ cells. Furthermore, SCs secrete extracellular vesicles (EVs) containing biologically active molecules including nucleic acids, lipids, and proteins. EVs are involved in various physiological and pathological processes and show promising non-cellular therapeutic uses to combat infertility. Several studies have indicated that SCs and/or their derived EVs transplantation plays a crucial role in the regeneration of different segments of the reproductive system, oocyte production, and initiation of sperm production. However, available evidence triggers the need to testify the efficacy of SC transplantation or EVs injection in resolving the infertility issues of the human population. In this review, we highlight the recent literature covering the issues of infertility in females and males, with a special focus on the possible treatments by stem cells or their derived EVs.

Rejuvenation of Helicobacter pylori-Associated Atrophic Gastritis Through Concerted Actions of Placenta-Derived Mesenchymal Stem Cells Prevented Gastric Cancer

Chronic Helicobacter pylori infection causes gastric cancer via the progression of precancerous chronic atrophic gastritis (CAG). Therefore, repairing gastric atrophy could be a useful strategy in preventing H. pylori-associated gastric carcinogenesis. Although eradication of the bacterial pathogen offers one solution to this association, this study was designed to evaluate an alternative approach using mesenchymal stem cells to treat CAG and prevent carcinogenesis. Here, we used human placenta-derived mesenchymal stem cells (PD-MSCs) and their conditioned medium (CM) to treat H. pylori-associated CAG in a mice/cell model to explore their therapeutic effects and elucidate their molecular mechanisms. We compared the changes in the fecal microbiomes in response to PD-MSC treatments, and chronic H. pylori-infected mice were given ten treatments with PD-MSCs before being sacrificed for end point assays at around 36 weeks of age. These animals presented with significant reductions in the mean body weights of the control group, which were eradicated following PD-MSC treatment (p < 0.01). Significant changes in various pathological parameters including inflammation, gastric atrophy, erosions/ulcers, and dysplastic changes were noted in the control group (p < 0.01), but these were all significantly reduced in the PD-MSC/CM-treated groups. Lgr5+, Ki-67, H⁺/K⁺-ATPase, and Musashi-1 expressions were all significantly increased in the treated animals, while inflammatory mediators, MMP, and apoptotic executors were significantly decreased in the PD-MSC group compared to the control group (p < 0.001). Our model showed that H. pylori-initiated, high-salt diet-promoted gastric atrophic gastritis resulted in significant changes in the fecal microbiome at the phylum/genus level and that PD-MSC/CM interventions facilitated a return to more normal microbial communities. In conclusion, administration of PD-MSCs or their conditioned medium may present a novel rejuvenating agent in preventing the progression of H. pylori-associated premalignant lesions.

Mesenchymal Stem Cells in Premature Ovarian Insufficiency: Mechanisms and Prospects

Premature ovarian insufficiency (POI) is a complex endocrine disease that severely affects the physiological and reproductive functions of females. The current conventional clinical treatment methods for POI are characterized by several side effects, and most do not effectively restore the physiological functions of the ovaries. Transplantation of mesenchymal stem cells (MSCs) is a promising regenerative medicine approach, which has received significant attention in the management of POI with high efficacy. Associated pre-clinical and clinical trials are also proceeding orderly. However, the therapeutic mechanisms underlying the MSCs-based treatment are complex and have not been fully elucidated. In brief, proliferation, apoptosis, immunization, autophagy, oxidative stress, and fibrosis of ovarian cells are modulated through paracrine effects after migration of MSCs to the injured ovary. This review summarizes therapeutic mechanisms of MSCs-based treatments in POI and explores their therapeutic potential in clinical practice. Therefore, this review will provide a theoretical basis for further research and clinical application of MSCs in POI.

Placenta: A gold mine for translational research and regenerative medicine

Stem cell therapy has gained much impetus in regenerative medicine due to some of the encouraging results obtained in the laboratory as well as in translational/clinical studies. Although stem cells are of various types and their therapeutic potential has been documented in several studies, mesenchymal stromal/stem cells (MSCs) have an edge, as in addition to being multipotent, these cells are easy to obtain and expand, pose fewer ethical issues, and possess immense regenerative potential when used in a scientifically correct manner. Currently, MSCs are being sourced from various tissues such as bone marrow, cord, cord blood, adipose tissue, dental tissue, etc., and, quite often, the choice depends on the availability of the source. One such rich source of tissue suitable for obtaining good quality MSCs in large numbers is the placenta obtained in a full-term delivery leading to a healthy child's birth. Several studies have demonstrated the regenerative potential of human placenta-derived MSCs (hPMSC), and most show that these MSCs possess comparable, in some instances, even better, therapeutic potential as that shown by human bone marrow-derived (hBMSC) or human umbilical cord-derived (hUC-MSC) MSCs. The placenta can be easily sourced from the OB/GYN department of any hospital, and if its derivatives such as hPMSC or their EVs are produced under GMP conditions, it could serve as a gold mine for translational/clinical research. Here, we have reviewed recent studies revealing the therapeutic potential of hPMSC and their extracellular vesicles (EVs) published over the past three years.

Is It Possible to Treat Infertility with Stem Cells?

Infertility is a major health problem, and despite improved treatments over the years, there are still some conditions that cannot be treated successfully using a conventional approach. Therefore, new options are being considered and one of them is cell therapy using stem cells. Stem cell treatments for infertility can be divided into two major groups, the first one being direct transplantation of stem cells or their paracrine factors into reproductive organs and the second one being in vitro differentiation into germ cells or gametes. In animal models, all of these approaches were able to improve the reproductive potential of tested animals, although in humans there is still too little evidence to suggest successful use. The reasons for lack of evidence are unavailability of proper material, the complexity of explored biological processes, and ethical considerations. Despite all of the above-mentioned hurdles, researchers were able to show that in women, it seems to be possible to improve some conditions, but in men, no similar clinically important improvement was achieved. To conclude, the data presented in this review suggest that the treatment of infertility with stem cells seems plausible, because some types of treatments have already been tested in humans, achieving live births, while others show great potential only in animal studies, for now.

Exosomes as Biomarkers for Female Reproductive Diseases Diagnosis and Therapy

Cell-cell communication is an essential mechanism for the maintenance and development of various organs, including the female reproductive system. Today, it is well-known that the function of the female reproductive system and successful pregnancy are related to appropriate follicular growth, oogenesis, implantation, embryo development, and proper fertilization, dependent on the main regulators of cellular crosstalk, exosomes. During exosome synthesis, selective packaging of different factors into these vesicles happens within the originating cells. Therefore, exosomes contain both genetic and proteomic data that could be applied as biomarkers or therapeutic targets in pregnancy-associated disorders or placental functions. In this context, the present review aims to compile information about the potential exosomes with key molecular cargos that are dysregulated in female reproductive diseases which lead to infertility, including polycystic ovary syndrome (PCOS), premature ovarian failure (POF), Asherman syndrome, endometriosis, endometrial cancer, cervical cancer, ovarian cancer, and preeclampsia, as well as signaling pathways related to the regulation of the reproductive system and pregnancy outcome during these pathological conditions. This review might help us realize the etiology of reproductive dysfunction and improve the early diagnosis and treatment of the related complications.

Stem Cell Paracrine Signaling for Treatment of Premature Ovarian Insufficiency

Premature ovarian insufficiency is a common disorder affecting young women and represents the worst-case ovarian scenario due to the substantial impact on the reproductive lifespan of these patients. Due to the complexity of this condition, which is not fully understood, non-effective treatments have yet been established for these patients. Different experimental approaches are being explored and strategies based on stem cells deserve special attention. The regenerative and immunomodulatory properties of stem cells have been successfully tested in different tissues, including ovary. Numerous works point out to the efficacy of stem cells in POI treatment, and a wide range of clinical trials have been developed in order to prove safety and effectiveness of stem cells therapy-in diminished ovarian reserve and POI women. The main purpose of this review is to describe the state of the art of the treatment of POI involving stem cells, especially those that use mobilization of stem cells or paracrine signaling.