Scaffold-based tissue engineering approaches in treating infertility

Employing novel biocompatible composite scaffolds with bioglass 58S and poly L-lactic acid for effective bone defect treatment

BACKGROUND

Bioglass materials have gained significant attention in the field of tissue engineering due to their osteoinductive and biocompatible properties that promote bone cell differentiation. In this study, a novel composite scaffold was developed using a sol-gel technique to combine bioglass (BG) 58 S with a poly L-lactic acid (PLLA).

METHODS AND RESULTS

The physiochemical properties, morphology, and osteoinductive potential of the scaffolds were investigated by X-ray diffraction analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results showed that the SiO2-CaO-P2O5 system was successfully synthesized by the sol-gel method. The PLLA scaffolds containing BG was found to be osteoinductive and promoted mineralization, as demonstrated by calcium deposition assay, upregulation of alkaline phosphatase enzyme activity, and Alizarin red staining data.

CONCLUSIONS

These in vitro studies suggest that composite scaffolds incorporating hBMSCs are a promising substitute material to be implemented in bone tissue engineering. The PLLA/BG scaffolds promote osteogenesis and support the differentiation of bone cells, such as osteoblasts, due to their osteoinductive properties.

Exploring the Role of Hyaluronic Acid in Reproductive Biology and Beyond: Applications in Assisted Reproduction and Tissue Engineering

Hyaluronic acid (HA) plays a prominent role in various aspects of reproductive biology and assisted reproductive technologies (ART). This review describes the multifaceted influence of HA, ranging from primordial germ cell migration, ovarian follicle development, and ovulation in females to sperm structure, physiology, motility, and capacitation in males. In addition, HA also plays an important role in fertilization and promotes embryo implantation by mediating cellular adhesion and communication within the uterus. Against this physiological background, the review examines the current applications of HA in the context of ART. In addition, the article addresses the emerging field of reproductive tissue engineering, where HA-based hydrogels offer promising perspectives as they can support the development of mature oocytes and spermatogenesis in vitro. Overall, this review highlights the integral role of HA in the intricate mechanisms of reproductive biology and its growing importance for improving ART outcomes and the field of tissue engineering of the reproductive system.

Janus adhesive microneedle patch loaded with exosomes for intrauterine adhesion treatment

Intrauterine adhesions (IUAs) are common sequelae of cervical mucosa damage caused by uterine curettage. Establishing an anti-adhesion barrier between the damaged endometrium with a sustained-release drug capability and hence promoting endogenous regeneration of the endometrium is an available treatment for IUA. However, current therapy lacks long-term intracavitary residence, drug-delivery permeability, and tissue anti-adhesion to the endometrium. Here, we report the design of a Janus microneedle patch consisting of two layers: an adhesive inner layer with an exosomes-loaded microneedle, which endows the patch with a tissue adhesive capability as well as transdermal drug-delivery capability; and an anti-adhesion outer layer, which prevents the intrauterine membrane from postoperative adhesion. This Janus adhesive microneedle patch firmly adhered to uterine tissue, and sustainedly released ∼80% of the total loaded exosomes in 7 days, hence promoting the expression of vascular- and endothelial-related cell signals. Furthermore, the anti-adhesive layer of the microneedle patch exhibited low cell and protein adhesion performance. In rats, the microneedle patch successfully prevented uterine adhesions, improved endometrial angiogenesis, proliferation, and hormone response levels. This study provides a stable anti-adhesion barrier as well as efficient drug-release capability treatment for intrauterine adhesion treatment.

Human umbilical cord-derived mesenchymal stem cells and auto-crosslinked hyaluronic acid gel complex for treatment of intrauterine adhesion

OBJECTIVE

The purpose of this study was to explore the therapeutic characteristics of mesenchymal stem cells generated from human umbilical cord (hUC-MSCs) when utilized in conjunction with auto-crosslinked hyaluronic acid gel (HA-gel) for the management of intrauterine adhesion (IUA). The goal was to see how this novel therapy could enhance healing and improve outcomes for IUA patients.

METHODS

In this study, models of intrauterine adhesion (IUA) were established in Sprague-Dawley (SD) rats, which were then organized and divided into hUC-MSCs groups. The groups involved: hUC-MSCs/HA-gel group, control group, and HA-gel group. Following treatment, the researchers examined the uterine cavities and performed detailed analyses of the endometrial tissues to determine the effectiveness of the interventions.

RESULTS

The results indicated that in comparison with to the control group, both HA-gel, hUC-MSCs, and hUC-MSCs/HA-gel groups showed partial repair of IUA. However, in a more notable fashion transplantation of hUC-MSCs/HA-gel complex demonstrated significant dual repair effects. Significant outcomes were observed in the group treated with hUC-MSCs and HA-gel, they showed thicker endometrial layers, less fibrotic tissue, and a higher number of endometrial glands. This treatment strategy also resulted in a significant improvement in fertility restoration, indicating a profound therapeutic effect.

CONCLUSIONS

The findings of this study suggest that both HA-gel, hUC-MSCs, and hUC-MSCs/HA-gel complexes have the potential for partial repair of IUA and fertility restoration caused by endometrium mechanical injury. Nonetheless, the transplantation of the hUC-MSCs/HA-gel complex displayed exceptional dual healing effects, combining effective anti-adhesive properties with endometrial regeneration stimuli.

Establishment and comparison of different procedures for modeling intrauterine adhesion in rats: A preliminary study

The establishment of a stable animal model for intrauterine adhesion (IUA) can significantly enhance research on the pathogenesis and pathological changes of this disease, as well as on the development of innovative therapeutic approaches. In this study, three different modeling methods, including phenol mucilage combined mechanical scraping, ethanol combined mechanical scraping and ethanol modeling alone were designed. The morphological characteristics of the models were evaluated. The underlying mechanisms and fertility capacity of the ethanol modeling group were analyzed and compared to those of the sham surgery group. All three methods resulted in severe intrauterine adhesions, with ethanol being identified as a reliable modeling agent and was subsequently subjected to further evaluation. Immunohistochemistry and RT-PCR results indicated that the ethanol modeling group exhibited an increase in the degree of fibrosis and inflammation, as well as a significant reduction in endometrial thickness, gland number, vascularization, and endometrial receptivity, ultimately resulting in the loss of fertility capacity. The aforementioned findings indicate that the intrauterine perfusion of 95 % ethanol is efficacious in inducing the development of intrauterine adhesions in rats. Given its cost-effectiveness, efficacy, and stability in IUA formation, the use of 95 % ethanol intrauterine perfusion may serve as a novel platform for evaluating innovative anti-adhesion materials and bioengineered therapies.

Current Status of Tissue Regenerative Engineering for the Treatment of Uterine Infertility

With the recent developments in tissue engineering, scientists have attempted to establish seed cells from different sources, create cell sheets through various technologies, implant them on scaffolds with various spatial structures, or load scaffolds with cytokines. These research results are very optimistic, bringing hope to the treatment of patients with uterine infertility. In this article, we reviewed articles related to the treatment of uterine infertility from the aspects of experimental treatment strategy, seed cells, scaffold application, and repair criteria so as to provide a basis for future research.

Biomaterials for Testicular Bioengineering: How far have we come and where do we have to go?

Traditional therapeutic interventions aim to restore male fertile potential or preserve sperm viability in severe cases, such as semen cryopreservation, testicular tissue, germ cell transplantation and testicular graft. However, these techniques demonstrate several methodological, clinical, and biological limitations, that impact in their results. In this scenario, reproductive medicine has sought biotechnological alternatives applied for infertility treatment, or to improve gamete preservation and thus increase reproductive rates in vitro and in vivo. One of the main approaches employed is the biomimetic testicular tissue reconstruction, which uses tissue-engineering principles and methodologies. This strategy pursues to mimic the testicular microenvironment, simulating physiological conditions. Such approach allows male gametes maintenance in culture or produce viable grafts that can be transplanted and restore reproductive functions. In this context, the application of several biomaterials have been proposed to be used in artificial biological systems. From synthetic polymers to decellularized matrixes, each biomaterial has advantages and disadvantages regarding its application in cell culture and tissue reconstruction. Therefore, the present review aims to list the progress that has been made and the continued challenges facing testicular regenerative medicine and the preservation of male reproductive capacity, based on the development of tissue bioengineering approaches for testicular tissue microenvironment reconstruction.

Intraovarian Administration of Autologous Menstrual Blood Derived-Mesenchymal Stromal Cells in Women with Premature Ovarian Failure

BACKGROUND

Premature ovarian failure (POF) is a well-known cause of infertility, particularly in women under the age of 40. POF is also associated with elevated gonadotropin levels, amenorrhea and sex-hormone deficiency.

AIM OF THE STUDY

In this study, the therapeutic potential of autologous mesenchymal stromal cells obtained from menstrual blood (Men-MSCs) for patients with POF was evaluated.

METHODS

15 POF patients were included in the study. The cultured Men-MSCs were confirmed by flow cytometry, karyotype, endotoxin and mycoplasma and were then injected into the patients' right ovary by vaginal ultrasound guidance and under general anesthesia and aseptic conditions. Changes in patients' anti-Müllerian hormone (AMH), antral follicle count (AFC), follicle-stimulating hormone (FSH), luteal hormone (LH), and estradiol (E2) levels, as well as general flushing and vaginal dryness were followed up to one year after treatment.

RESULTS

All patients were satisfied with a decrease in general flushing and vaginal dryness. 4 patients (2.9%) showed a spontaneous return of menstruation without additional pharmacological treatment. There was a significant difference in AFC (0 vs. 1 ± 0.92 count, p value ≤0.001%), FSH (74 ± 22.9 vs. 54.8 ± 17.5 mIU/mL, p-value ≤0.05%), E2 (10.2 ± 6 vs. 21.8 ± 11.5 pg/mL p-value ≤0.01%), LH (74 ± 22.9 vs. 54.8 ± 17.5 IU/L,p-value ≤0.01%) during 3 months post-injection. However, there were no significant changes in AMH (p-value ≥0.05%). There were also no significant differences in assessed parameters between 3 and 6 months after cell injection.

CONCLUSION

According to the findings of this study, administration of Men-MSCs improved ovarian function and menstrual restoration in some POF patients.

Understanding main pregnancy complications through animal models

Since human pregnancy is an inefficient process, achieving desired and pleasant outcome of pregnancy - the birth of a healthy and fit baby - is the main goal in any pregnancy. Spontaneous pregnancy failure is actually the most common complication of pregnancy and Most of these pregnancy losses are not known. Animal models have been utilized widely to investigate the system of natural biological adaptation to pregnancy along with increasing our comprehension of the most important hereditary and non-hereditary factors that contribute to pregnancy disorders. We use model organisms because their complexity better reproduces the human condition. A useful animal model for the disease should be pathologically similar to the disease conditions in humans. Animal models deserve a place in research because of the ethical limitations that apply to pregnant women's experiments. The present review provides insights into the overall risk factors involved in recurrent miscarriage, recurrent implant failure and preeclampsia and animal models developed to help researchers identify the source of miscarriage and the best research and treatment strategy for women with Repeated miscarriage and implant failure.

Recent scaffold-based tissue engineering approaches in premature ovarian failure treatment

Recently, tissue engineering and regenerative medicine have received significant attention with outstanding advances. The main scope of this technology is to recover the damaged tissues and organs or to maintain and improve their function. One of the essential fields in tissue engineering is scaffold designing and construction, playing an integral role in damaged tissues reconstruction and repair. However, premature ovarian failure (POF) is a disorder causing many medical and psychological problems in women. POF treatment using tissue engineering and various scaffold has recently made tremendous and promising progress. Due to the importance of the subject, we have summarized the recently examined scaffolds in the treatment of POF in this review.

Whole-organ decellularization of the human uterus and in vivo application of the bio-scaffolds in animal models

PURPOSE

The aim of this investigation was to design a perfusion-based decellularization protocol to provide whole human uterine bio-scaffolds with preserved structural and componential characteristics and to investigate the in vivo properties of the decellularized tissues.

METHODS

Eight human uteri, donated by brain-dead patients, were decellularized by perfusion of sodium dodecyl sulfate (SDS) through the uterine arteries using a peristaltic pump. The bio-scaffolds were evaluated and compared with native human uterus regarding histological, immunohistochemical, structural, and bio-mechanical properties, in addition to CT angiographies to examine the preservation of the vascular networks. Subsequently, we obtained acellular patches and implanted them on uterine defects of female Wistar rats to investigate the bio-compatibility and regenerative potential of the bio-scaffolds. Finally, we performed immunostaining to investigate the potential role of circulating stem cells in recellularization of the implanted bio-scaffolds.

RESULTS

The outcomes of this investigation confirmed the efficacy of the proposed protocol to provide whole human uterine scaffolds with characteristics and extra-cellular matrix components similar to the native human uterus. Subsequent in vivo studies demonstrated the bio-compatibility and the regenerative potential of the scaffolds and suggested a signaling pathway as an underlying mechanism for the regenerative process.

CONCLUSIONS

To the best of our knowledge, this investigation provides the first efficient perfusion-based decellularization protocol for the human uterus to obtain whole-organ scaffolds. The outcomes of this investigation could be employed in future human uterus tissue engineering studies which could ultimately result in the development of novel treatments for female infertile patients.

Medical Applications of Porous Biomaterials: Features of Porosity and Tissue-Specific Implications for Biocompatibility

Porosity is an important material feature commonly employed in implants and tissue scaffolds. The presence of material voids permits the infiltration of cells, mechanical compliance, and outward diffusion of pharmaceutical agents. Various studies have confirmed that porosity indeed promotes favorable tissue responses, including minimal fibrous encapsulation during the foreign body reaction (FBR). However, increased biofilm formation and calcification is also described to arise due to biomaterial porosity. Additionally, the relevance of host responses like the FBR, infection, calcification, and thrombosis are dependent on tissue location and specific tissue microenvironment. In this review, the features of porous materials and the implications of porosity in the context of medical devices is discussed. Common methods to create porous materials are also discussed, as well as the parameters that are used to tune pore features. Responses toward porous biomaterials are also reviewed, including the various stages of the FBR, hemocompatibility, biofilm formation, and calcification. Finally, these host responses are considered in tissue specific locations including the subcutis, bone, cardiovascular system, brain, eye, and female reproductive tract. The effects of porosity across the various tissues of the body is highlighted and the need to consider the tissue context when engineering biomaterials is emphasized.

Stem cells technology as a platform for generating reproductive system organoids and treatment of infertility-related diseases

In recent years, stem cells have known as a helpful biological tool for the accurate diagnosis, treatment and recognition of diseases. Using stem cells as biomarkers have presented high potential in the early detection of many diseases. Another advancement in stem cell technology includes stem cell derived organoids model that could be a promising platform for diagnosis and modeling different diseases. Furthermore, therapeutic capabilities of stem cell therapy have increased hope in the face of different disability managements. All of these technologies are also widely used in reproductive related diseases especially in today's world that many couples encounter infertility problems. However, with the aid of numerous improvements in the treatment of infertility, over 80% of couples who dreamed of having children could now have children. Due to the fact that infertility has many negative effects on personal and social lives of young couples, many researchers have focused on the treatment of male and female reproductive system abnormalities with different types of stem cells, including embryonic stem cells, bone marrow mesenchymal stem cells (MSCs), and umbilical cord-derived MSCs. Also, design and formation of reproductive system organoids provide a fascinating window into disease modeling, drug screening, personalized therapy, and regeneration medicine. Utilizing these techniques to study, model and treat the infertility-related diseases has drawn attention of many scientists. This review explains different applications of stem cells in generating reproductive system organoids and stem cell-based therapies for male and female infertility related diseases treatment.

Cell-based therapy in thin endometrium and Asherman syndrome

Numerous treatment strategies have so far been proposed for treating refractory thin endometrium either without or with the Asherman syndrome. Inconsistency in the improvement of endometrial thickness is a common limitation of such therapies including tamoxifen citrate as an ovulation induction agent, acupuncture, long-term pentoxifylline and tocopherol or tocopherol only, low-dose human chorionic gonadotropin during endometrial preparation, aspirin, luteal gonadotropin-releasing hormone agonist supplementation, and extended estrogen therapy. Recently, cell therapy has been proposed as an ideal alternative for endometrium regeneration, including the employment of stem cells, platelet-rich plasma, and growth factors as therapeutic agents. The mechanisms of action of cell therapy include the cytokine induction, growth factor production, natural killer cell activity reduction, Th17 and Th1 decrease, and Treg cell and Th2 increase. Since cell therapy is personalized, dynamic, interactive, and specific and could be an effective strategy. Despite its promising nature, further research is required for improving the procedure and the safety of this strategy. These methods and their results are discussed in this article.

Uterine Tissue Engineering: Where We Stand and the Challenges Ahead

Tissue engineering is an innovative approach to develop allogeneic tissues and organs. The uterus is a very sensitive and complex organ, which requires refined techniques to properly regenerate and even, to rebuild itself. Many therapies were developed in 20th century to solve reproductive issues related to uterus failure and, more recently, tissue engineering techniques provided a significant evolution in this issue. Herein we aim to provide a broad overview and highlights of the general concepts involved in bioengineering to reconstruct the uterus and its tissues, focusing on strategies for tissue repair, production of uterine scaffolds, biomaterials and reproductive animal models, highlighting the most recent and effective tissue engineering protocols in literature and their application in regenerative medicine. In addition, we provide a discussion about what was achieved in uterine tissue engineering, the main limitations, the challenges to overcome and future perspectives in this research field.

Matrigel/Umbilical Cord-Derived Mesenchymal Stem Cells Promote Granulosa Cell Proliferation and Ovarian Vascularization in a Mouse Model of Premature Ovarian Failure

In women of reproductive age, severe injuries to the ovary are often accompanied by premature ovarian failure (POF), which can result in amenorrhea or infertility. Hormone replacement therapy has been used to treat POF; however, it has limited therapeutic efficiency and may cause several side effects. In this study, we aimed to fabricate a Matrigel scaffold loaded with human umbilical cord-derived mesenchymal stem cells (MSCs) and explore its potential to restore ovarian function and repair ovarian structures in vitro and in vivo. POF mouse models were established by injecting mice with cyclophosphamide for 15 consecutive days. Then, MSC/Matrigel was transplanted into the ovaries of the mice. Five weeks later, the morphology of the ovaries and follicles was observed by hematoxylin/eosin staining, and the tissue fibrosis ratio was measured using Masson's trichrome staining. The number of blood vessels was evaluated by α-smooth muscle actin and CD31 immunofluorescence, and Ki67 expression was used to determine the proliferation of granulosa cells. The expression of vascular endothelial growth factor (VEGF)-A was assessed by western blotting. The Matrigel scaffold regulated the expression of VEGF-A in vitro. Moreover, it promoted MSC survival and proliferation and prevented MSC apoptosis in vivo. After the transplantation of the MSC/Matrigel, the number of follicles was significantly increased in the mice with POF, and the tissue fibrosis ratio was reduced. Furthermore, the MSC/Matrigel significantly improved the proliferation rate of granulosa cells, increased the number of blood vessels, and upregulated the expression of VEGF-A. These findings demonstrate that MSC/Matrigel may support follicular development and help restore ovarian structures in vivo.

The promising biological role of postbiotics derived from probiotic Lactobacillus species in reproductive health

Recent investigations have meaningfully developed our knowledge of the features of the reproductive microbiome/metabolome profile and their relations with host responses to offer an optimal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy. In this context, the establishment of homeostatic circumstances in the Female Reproductive Tract (FRT), in various physiological periods, is a significant challenge, which appears the application of postbiotics can facilitate the achievement of this goal. So, currently, scientific literature confirms that postbiotics due to their antimicrobial, antiviral, and immunomodulatory properties can be considered as a novel biotherapeutic approach. Future investigation in this field will shed more translational mechanistic understanding of the interaction of the postbiotics derived from vaginal Lactobacilli with females' health and reproduction.

Differentiation and proliferation of spermatogonial stem cells using a three-dimensional decellularized testicular scaffold: a new method to study the testicular microenvironment in vitro

PURPOSE

Successful in vitro transplantation of spermatogonial stem cells (SSCs) demands effective culture systems for SSCs proliferation and differentiation. Natural extracellular matrix (ECM) creates a microenvironment suitable for culture of stem cells. In the present study, we intended to assess the capability of the porous scaffold consisting of hyaluronic acid (HA), chitosan, and decellularized testicular matrix (DTM) as a proper niche for SSCs seeding.

METHODS

The testes of four NMRI mice were extracted for further detergent-based decellularization process. We isolated, cultured, and clarified neonate mouse SSC, and a three-dimensional scaffold was prepared for SSCs culture. The loaded SSCs and hydrogel-based scaffold were investigated by several studies including scanning electron microscopy (SEM), 4',6-diamidino-2-phenylindole (DAPI), 3-[4, 5-dimethyl (thiazol-2yl)-3,5diphenyl] tetrazolium bromide (MTT), Acridine orange, and Immunohistochemistry (IHC) staining.

RESULTS

The efficiency of decellularization process was confirmed by DAPI, hematoxylin and eosin (H&E), and Masson's Trichrome staining. Acridine orange also depicted SSCs proliferation and viability. SEM approved the preservation of ECM components and also showed complex, coiled, and tubular seminiferous tubules, with intact and condensed collagenous form of the tunica albuginea. MTT test also revealed the scaffold's non-toxicity. Expression of PLZF, TP1, and TEKT1 markers also verified the capacity of SSCs proliferation on a cogel scaffold.

CONCLUSION

In conclusion, cogel scaffold consisting of DTM, HA, and chitosan may provide the supporting layer for in vitro SSC differentiation and proliferation.

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.

Recent developments in bio-scaffold materials as delivery strategies for therapeutics for endometrium regeneration

Intrauterine adhesions (IUAs) refer to the repair disorder after endometrial injury and may lead to uterine infertility, recurrent miscarriage, abnormal menstrual bleeding, and other obstetric complications. It is a pressing public health issue among women of childbearing age. Presently, there are limited clinical treatments for IUA, and there is no sufficient evidence that these treatment modalities can effectively promote regeneration after severe endometrial injury or improve pregnancy outcome. The inhibitory pathological micro-environment is the main factor hindering the repair of endometrial damaged tissues. To address this, tissue engineering and regenerative medicine have been achieving promising developments. Particularly, biomaterials have been used to load stem cells or therapeutic factors or construct an in situ delivery system as a treatment strategy for endometrial injury repair. This article comprehensively discusses the characteristics of various bio-scaffold materials and their application as stem cell or therapeutic factor delivery systems constructed for uterine tissue regeneration.

Current progress, challenges, and future prospects of testis organoids†

Spermatogenic failure is believed to be a major cause of male infertility. The establishment of a testis organoid model would facilitate the study of such pathological mechanisms and open the possibility of male fertility preservation. Because of the complex structures and cellular events occurring within the testis, the establishment of a compartmentalized testis organoid with a complete spermatogenic cycle remains a challenge in all species. Since the late 20th century, a great variety of scaffold-based and scaffold-free testis cell culture systems have been established to recapitulate de novo testis organogenesis and in vitro spermatogenesis. The utilization of the hydrogel scaffolds provides a 3D microenvironment for testis cell growth and development, facilitating the reconstruction of de novo testis tissue-like structures and spermatogenic differentiation. Using a combination of different strategies, including the use of various scaffolding biomaterials, the incorporation of the living cells with high self-assembling capacity, and the integration of the advanced fabrication techniques, a scaffold-based testis organoid with a compartmentalized structure that supports in vitro spermatogenesis may be achieved. This article briefly reviews the current progress in the development of scaffold-based testis organoids while focusing on the scaffolding biomaterials (hydrogels), cell sources, and scaffolding approaches. Key challenges in current organoid studies are also discussed along with recommendations for future research.