Germ cell differentiation of bone marrow mesenchymal stem cells

Enhancing Spermatogenesis in Non-obstructive Azoospermia Through Mesenchymal Stem Cell Therapy22

Stem cells hold great promise as novel and encouraging therapeutic tools in the treatment of degenerative disorders due to their differentiation potential while maintaining the capability to self-renewal and their unlimited ability to divide and regenerate tissue. A variety of different types of stem cells can be used in cell therapy. Among these, mesenchymal stem cell (MSC) therapy has gradually established itself as a novel method for treating damaged tissues that need restoration and renewal. Male infertility is an important health challenge affecting approximately 8-12% of people around the world. This abnormality can be caused by primary, congenital, acquired, or idiopathic reasons. Men with no sperm in their semen have a condition called azoospermia, caused by non-obstructive (NOA) causes and post-testicular obstructive causes. Accumulating evidence has shown that various types of MSCs can differentiate into germ cells and improve spermatogenesis in the seminiferous tubules of animal models. In addition, recent studies in animal models have exhibited that extracellular vesicles derived from MSCs can stimulate the progression of spermatogenesis and germ cell regeneration in the recipient testes. In spite of the fact that various improvements have been made in the treatment of azoospermia disorder in animal models by MSC or their extracellular vesicles, no clinical trials have been carried out to test their therapeutic effect on the NOA. In this review, we summarize the potential of MSC transplantation for treating infertility caused by NOA.

Advances of three-dimensional (3D) culture systems for in vitro spermatogenesis

The loss of germ cells and spermatogenic failure in non-obstructive azoospermia are believed to be the main causes of male infertility. Laboratory studies have used in vitro testicular models and different 3-dimensional (3D) culture systems for preservation, proliferation and differentiation of spermatogonial stem cells (SSCs) in recent decades. The establishment of testis-like structures would facilitate the study of drug and toxicity screening, pathological mechanisms and in vitro differentiation of SSCs which resulted in possible treatment of male infertility. The different culture systems using cellular aggregation with self-assembling capability, the use of different natural and synthetic biomaterials and various methods for scaffold fabrication provided a suitable 3D niche for testicular cells development. Recently, 3D culture models have noticeably used in research for their architectural and functional similarities to native microenvironment. In this review article, we briefly investigated the recent 3D culture systems that provided a suitable platform for male fertility preservation through organ culture of testis fragments, proliferation and differentiation of SSCs.

Therapeutic potential of bone marrow mesenchymal stem cells in cyclophosphamide-induced infertility

Cancer is a deadly disease characterized by abnormal cell proliferation. Chemotherapy is one technique of cancer treatment. Cyclophosphamide (CYP) is the most powerful chemotherapy medication, yet it has serious adverse effects. It is an antimitotic medicine that regulates cell proliferation and primarily targets quickly dividing cells, and it has been related to varying levels of infertility in humans. In the current study, we assessed the biochemical, histological, and microscopic evaluations of testicular damage following cyclophosphamide administration. Further, we have explored the potential protective impact of mesenchymal stem cell (MSCs) transplantation. The biochemical results revealed that administration of cyclophosphamide increased serum concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), while it decreased serum concentrations of free testosterone hormone (TH), testicular follicle-stimulating hormone, luteinizing hormone, and free testosterone hormone concentrations, testicular total antioxidant capacity (TAC), and testicular activity of superoxide dismutase (SOD) enzyme. The histology and sperm examinations revealed that cyclophosphamide induced destruction to the architectures of several tissues in the testes, which drastically reduced the Johnsen score as well as the spermatogenesis process. Surprisingly, transplantation of mesenchymal stem cell after cyclophosphamide administration altered the deterioration effect of cyclophosphamide injury on the testicular tissues, as demonstrated by biochemical and histological analysis. Our results indicated alleviation of serum and testicular sex hormones, as well as testicular oxidative stress markers (total antioxidant capacity and superoxide dismutase activity), and nearly restored the normal appearance of the testicular tissues, Johnsen score, and spermatogenesis process. In conclusion, our work emphasizes the protective pharmacological use of mesenchymal stem cell to mitigate the effects of cyclophosphamide on testicular tissues that impair the spermatogenesis process following chemotherapy. These findings indicate that transferring mesenchymal stem cell to chemotherapy patients could significantly improve spermatogenesis.

Generation of male germ cells in vitro from the stem cells

Infertility has become a serious disease since it affects 10%-15% of couples worldwide, and male infertility contributes to about 50% of the cases. Notably, a significant decrease occurs in the newborn population by 7.82 million in 2020 compared to 2016 in China. As such, it is essential to explore the effective methods of obtaining functional male gametes for restoring male fertility. Stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), spermatogonial stem cells (SSCs), and mesenchymal stem cells (MSCs), possess the abilities of both self-renewal and differentiation into germ cells. Significantly, much progress has recently been achieved in the generation of male germ cells in vitro from various kinds of stem cells under the specified conditions, e.g., the coculturing with Sertoli cells, three-dimensional culture system, the addition of growth factors and cytokines, and/or the overexpression of germ cell-related genes. In this review, we address the current advance in the derivation of male germ cells in vitro from stem cells based on the studies of the peers and us, and we highlight the perspectives and potential application of stem cell-derived male gametes in reproductive medicine.

Mesenchymal stromal/stem cells and their exosomes for restoration of spermatogenesis in non-obstructive azoospermia: a systemic review

Stem cells have been introduced as new promising therapeutic agents in treatment of degenerative diseases because of having high differentiation potential while maintaining the ability to self-replicate and retaining features of their source cells. Among different type of cell therapies, mesenchymal stromal/stem cell (MSC) therapy is being increasingly developed as a new way to treat structural defects that need to be repaired and regenerated. Non-obstructive azoospermia (NOA) is a reproductive disease in men that causes infertility in 10% of infertile men. Based on in vitro studies, MSCs from different tissue sources have been differentiated into germ cells or gamete progenitor cells by simple methods in both male and female. On the other hand, the therapeutic effects of MSCs have been evaluated for the treatment of NOA animal models created by chemical or surgical compounds. The results of these studies confirmed successful allotransplantation or xenotransplantation of MSCs in the seminiferous tubules. As well, it has been reported that exosomes secreted by MSCs are able to induce the process of spermatogenesis in the testes of infertile animal models. Despite numerous advances in the treatment of reproductive diseases in men and women with the help of MSCs or their exosomes, no clinical trial has been terminated on the treatment of NOA. This systematic review attempts to investigate the possibility of MSC therapy for NOA in men.

Characterization and cytocompatibility of 3D porous biomimetic scaffold derived from rabbit nucleus pulposus tissue in vitro

Intervertebral disc (IVD) degeneration is one of the most important causes of lower back pain. Tissue engineering provides a new method for the experimental treatment of degenerative disc diseases. This study aims to develop a natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus. The nucleus pulposus (NP) was decellularized by sequential detergent-nuclease methods, including physical crushing, freeze-drying and cross-linking. These 3D porous scaffolds were fabricated with a high porosity of (81.28 ± 4.10)%, an ideal pore size with appropriate mechanical properties. Rabbit bone marrow mesenchymal stem cells (rBMSCs) were seeded and cultured on the scaffolds. And the mechanical tests showed the compressive elastic modulus of the scaffolds cultured for 4 weeks reached 0.12 MPa, which was better than that of the scaffolds cultured for 2 weeks (0.07 MPa) and that of the control group (0.04 MPa). Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration and secretion of seeded cells in vitro. As assays like histology, immunohistochemistry and the real-time qRT-PCR showed, NP-like tissues were preliminarily formed. In conclusion, the 3D porous scaffold derived from NP ECM is a potential biomaterial for the regeneration of NP tissues. A natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus was developed by sequential detergent-nuclease and freeze-drying method, which can reduce the damage of protein activity to the minimum. It is very similar to the composition and internal environment of the natural nucleus pulposus, because it derived from the natural nucleus pulposus. Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration, and secretion of seeded cells in vitro.

Evaluating differentiation potential of the human menstrual blood-derived stem cells from infertile women into oocyte-like cells

One of the most intricate infertility problems among women is the number and quality of the oocytes. Menstrual blood-derived stem cells (MenSCs) are a recently discovered source of mesenchymal stem cells which is known as a suitable source of cells for regenerative medicine. We aimed to investigate whether MenSCs as autologous cell source from endometriosis, PCOS, and healthy women have different characteristics regarding their morphology, CD marker expression pattern, differentiation potential into oocyte-like cells, and oocyte-related genes expression. Menstrual blood samples (1-2 ml) from healthy and infertile women (PCOS and endometriosis) in the age range of 22-35 years were collected. Isolated MenSCs by the Ficoll-Paque density-gradient centrifugation method was characterized by flow cytometry. MenSCs were induced under 20 % follicular fluid (FF), and then they were evaluated for differentiation by Real time-PCR and immunocytochemistry assay. MenSCs derived from endometriosis women had different morphology from PCOS and healthy women, but similar regarding their CD marker pattern. All induced MenSCs showed morphological changes and expressed oocyte related genes (STELLA, GDF9, STRA8, PRDM, LHR, FSHR, SCP3, DDX4, and ZP2) in the 2nd week of culture, but there was a significant difference between the groups. Endometriosis-derived MenSCs showed higher levels of both gene and protein expressions. These findings propose that MenSCs derived from endometriosis and PCOS patients under 20 % FF, not only could differentiate into oocyte-like cells, but also showed more differential potential in comparison with healthy women. This indicates the possibility of using the patients' own MenSCs to differentiate into the oocyte-like cells.

Differentiation potential of adipose tissue-derived mesenchymal stem cells into germ cells with and without growth factors

This study aimed to culture the adipose tissue-derived mesenchymal stem cells (AT-MSCs) with and without leukaemia inhibitory factor (LIF), glial cell line-derived neurotrophic factor (GDNF), epidermal growth factor (EGF) and retinoic acid (RA), and investigate their impact on the differentiation of these cells into germ cells. MSCs were separated from adipose tissue of mice, and the nature of these cells is confirmed by flow cytometry. The cells were cultured in different conditions, including MSCs grown in the presence of the growth factors, MSCs without the growth factors, MSCs cultured with combined growth factors and RA, and MSCs cultured with RA. After 2 weeks, the gene expression of c-Kit, Gcnf, Mvh and Scp3 and the protein expression of c-Kit and Gcnf were assessed by real-time PCR and Western blot, respectively. Scp3 was overexpressed in the groups supplemented with RA (p < .01). The expression of c-Kit and Mvh in the growth factor-supplemented groups was increased (p < .01). Western blot analysis confirmed the real-time PCR results. The use of the growth factors for the long-term culture of stem cells can be beneficial. However, to promote germ cell differentiation, the growth factors might be used by other meiosis inducer factors, such as RA.

Preventive Effects of Intrauterine Injection of Bone Marrow-Derived Mesenchymal Stromal Cell-Conditioned Media on Uterine Fibrosis Immediately after Endometrial Curettage in Rabbit

Uterine fibrosis is an acquired disorder leading to menstrual irregularities, implantation impairment, and abortion. Mesenchymal stromal cells (MSCs) have antifibrotic properties through chemokine secretion. MSC-conditioned media (MSC-CM) contain paracrine components—exosomes—with a great potential for repairing damaged tissue or preventing fibrosis. The main goal of this study was to evaluate the preventive effects of bone marrow-derived MSC-CM (BM-MSC-CM) on uterine fibrosis after uterine curettage in rabbits. This study included 12 female rabbits (24 uterine horns in total). Excised uteri of each of the 12 female rabbits were randomly divided into four groups of intact negative control, curettage positive control, BM-MSC injection, and BM-MSC-CM injection in the way that two corresponding uteri from a rabbit were allocated to different groups. The MSC-CM were collected from cultivated BM-MSCs 48 hours after having been washed three times and replaced in serum-free media. Through a surgical approach, the caudal parts of the uteri were submitted to traumatic endometrial curettage, except for the intact negative uteri. After suturing the uterine walls, BM-MSCs or BM-MSC-CM were injected in the curettage site. Endometrial regeneration was histologically evaluated 30 days after treatment. Based on the evaluation of histomorphometric indices, curettage with or without preventive injections increased the growth of endometrial layers. However, the amount of fibrotic tissue in the CM and the BM-MSC injection groups was the same as the normal control groups, and all were less than the curettage group. A single injection of CM of MSCs after 30 days prevented the fibrotic tissue formation induced by curettage in endometrial layers of rabbits. Injecting BM-MSC-CM immediately after curettage prevented and reduced the uterine fibrosis similar to BM-MSCs in a rabbit model.

Potential use of stem cells for fertility preservation

BACKGROUND

Infertility and gonadal dysfunction can result from gonadotoxic therapies, environmental exposures, aging, or genetic conditions. In men, non-obstructive azoospermia (NOA) results from defects in the spermatogenic process that can be attributed to spermatogonial stem cells (SSC) or their niche, or both. While assisted reproductive technologies and sperm banking can enable fertility preservation (FP) in men of reproductive age who are at risk for infertility, FP for pre-pubertal patients remains experimental. Therapeutic options for NOA are limited. The rapid advance of stem cell research and of gene editing technologies could enable new FP options for these patients. Induced pluripotent stem cells (iPSC), SSC, and testicular niche cells, as well as mesenchymal stromal cells (aka medicinal signaling cells, MSCs), have been investigated for their potential use in male FP strategies.

OBJECTIVE

Here, we review the benefits and challenges for three types of stem cell-based approaches under investigation for male FP, focusing on the role that promising sources of MSC derived from human umbilical cord, specifically human umbilical cord perivascular cells (HUCPVC), could fulfill. These approaches are as follows: 1. isolation and ex vivo expansion of autologous SSC for in vivo transplantation or in vitro spermatogenesis; 2. in vitro differentiation toward germ cell and testicular somatic cell lineages using autologous SSC, or stem cells such iPSC or MSC; and 3. protection or regeneration of the spermatogenic niche after gonadotoxic insults in vivo.

CONCLUSION

Our studies suggest that HUCPVC are promising sources of cells that could be utilized in multiple aspects of male FP strategies.