Platelet-rich plasma improves therapeutic effects of menstrual blood-derived stromal cells in rat model of intrauterine adhesion. Stem Cell Res Ther. 2019;10:61. [PMID: 30770774 PMCID: PMC6377773 DOI: 10.1186/s13287-019-1155-7]

Intrauterine infusion of platelet-rich plasma improves fibrosis by transforming growth factor beta 1/Smad pathway in a rat intrauterine adhesion model

This study aims to elucidate the effects of Platelet-rich plasma (PRP) in fibrosis development in intrauterine adhesion (IUA), and the associated underlying mechanisms are also explored, which are expected to be a potential therapeutic scheme for IUA. In this research, PRP was obtained and prepared from the peripheral venous blood of rats. A rat model was induced by mechanical injury. Further, PRP was directly injected into the uterus for treatment. The appearance and shape of the uterus were assessed based on the tissues harvested. The fibrosis biomarker levels were analyzed. The transforming growth factor beta 1 (TGF-β1) and Mothers against decapentaplegic homolog 7 (Smad7) levels, the phosphorylation of Smad2 (p-Smad2), and the phosphorylation of Smad3 (p-Smad3) were analyzed, and the molecular mechanism was investigated by rescue experiments. It was found that PRP improved the appearance and shape of the uterus in IUA and increased endometrial thickness and gland numbers. The administration of PRP resulted in a decrease in the expressions of fibrosis markers including collagen I, α-SMA, and fibronectin. Furthermore, PRP increased Smad7 levels and decreased TGF-β1 levels, p-Smad2, and p-Smad3. Meanwhile, administration of TGF-β1 activator reversed the therapeutic effects of PRP in IUA. Collectively, the intrauterine infusion of PRP can promote endometrial damage recovery and improve endometrial fibrosis via the TGF-β1/Smad pathway. Hence, PRP can be a potential therapeutic strategy for IUA.

Evolution of biotechnological advances and regenerative therapies for endometrial disorders: a systematic review

BACKGROUND

The establishment and maintenance of pregnancy depend on endometrial competence. Asherman syndrome (AS) and intrauterine adhesions (IUA), or endometrial atrophy (EA) and thin endometrium (TE), can either originate autonomously or arise as a result from conditions (i.e. endometritis or congenital hypoplasia), or medical interventions (e.g. surgeries, hormonal therapies, uterine curettage or radiotherapy). Affected patients may present an altered or inadequate endometrial lining that hinders embryo implantation and increases the risk of poor pregnancy outcomes and miscarriage. In humans, AS/IUA and EA/TE are mainly treated with surgeries or pharmacotherapy, however the reported efficacy of these therapeutic approaches remains unclear. Thus, novel regenerative techniques utilizing stem cells, growth factors, or tissue engineering have emerged to improve reproductive outcomes.

OBJECTIVE AND RATIONALE

This review comprehensively summarizes the methodologies and outcomes of emerging biotechnologies (cellular, acellular, and bioengineering approaches) to treat human endometrial pathologies. Regenerative therapies derived from human tissues or blood which were studied in preclinical models (in vitro and in vivo) and clinical trials are discussed.

SEARCH METHODS

A systematic search of full-text articles available in PubMed and Embase was conducted to identify original peer-reviewed studies published in English between January 2000 and September 2023. The search terms included: human, uterus, endometrium, Asherman syndrome, intrauterine adhesions, endometrial atrophy, thin endometrium, endometritis, congenital hypoplasia, curettage, radiotherapy, regenerative therapy, bioengineering, stem cells, vesicles, platelet-rich plasma, biomaterials, microfluidic, bioprinting, organoids, hydrogel, scaffold, sheet, miRNA, sildenafil, nitroglycerine, aspirin, growth hormone, progesterone, and estrogen. Preclinical and clinical studies on cellular, acellular, and bioengineering strategies to repair or regenerate the human endometrium were included. Additional studies were identified through manual searches.

OUTCOMES

From a total of 4366 records identified, 164 studies (3.8%) were included for systematic review. Due to heterogeneity in the study design and measured outcome parameters in both preclinical and clinical studies, the findings were evaluated qualitatively and quantitatively without meta-analysis. Groups using stem cell-based treatments for endometrial pathologies commonly employed mesenchymal stem cells (MSCs) derived from the human bone marrow or umbilical cord. Alternatively, acellular therapies based on platelet-rich plasma (PRP) or extracellular vesicles are gaining popularity. These are accompanied by the emergence of bioengineering strategies based on extracellular matrix (ECM)-derived hydrogels or synthetic biosimilars that sustain local delivery of cells and growth factors, reporting promising results. Combined therapies that target multiple aspects of tissue repair and regeneration remain in preclinical testing but have shown translational value. This review highlights the myriad of therapeutic material sources, administration methods, and carriers that have been tested.

WIDER IMPLICATIONS

Therapies that promote endometrial proliferation, vascular development, and tissue repair may help restore endometrial function and, ultimately, fertility. Based on the existing evidence, cost, accessibility, and availability of the therapies, we propose the development of triple-hit regenerative strategies, potentially combining high-yield MSCs (e.g. from bone marrow or umbilical cord) with acellular treatments (PRP), possibly integrated in ECM hydrogels. Advances in biotechnologies together with insights from preclinical models will pave the way for developing personalized treatment regimens for patients with infertility-causing endometrial disorders such as AS/IUA, EA/TE, and endometritis.

REGISTRATION NUMBER

https://osf.io/th8yf/.

Injectable "Homing-Like" Bioactive Short-Fibers for Endometrial Repair and Efficient Live Births

The prevalence of infertility caused by endometrial defects is steadily increasing, posing a significant challenge to women's reproductive health. In this study, injectable "homing-like" bioactive decellularized extracellular matrix short-fibers (DEFs) of porcine skin origin are innovatively designed for endometrial and fertility restoration. The DEFs can effectively bind to endometrial cells through noncovalent dipole interactions and release bioactive growth factors in situ. In vitro, the DEFs effectively attracted endometrial cells through the "homing-like" effect, enabling cell adhesion, spreading, and proliferation on their surface. Furthermore, the DEFs effectively facilitated the proliferation and angiogenesis of human primary endometrial stromal cells (HESCs) and human umbilical vein endothelial cells (HUVECs), and inhibited fibrosis of pretreated HESCs. In vivo, the DEFs significantly accelerated endometrial restoration, angiogenesis, and receptivity. Notably, the deposition of endometrial collagen decreased from 41.19 ± 2.16% to 14.15 ± 1.70% with DEFs treatment. Most importantly, in endometrium-injured rats, the use of DEFs increased the live birth rate from 30% to an impressive 90%, and the number and development of live births close to normal rats. The injectable "homing-like" bioactive DEFs system can achieve efficient live births and intrauterine injection of DEFs provides a new promising clinical strategy for endometrial factor infertility.

Obesity attenuates the beneficial effect of an intrauterine infusion of autologous platelet-rich plasma during in vitro fertilization

OBJECTIVE

To assess how obesity, normal weight (NW) versus overweight/obese (OW/OB), impacts platelet-rich plasma's (PRP) effectiveness during in vitro fertilization and how obesity affects platelets during the menstrual cycle.

METHODS

Endometrial mean thickness (EMT), embryo implantation, and clinical pregnancy were assessed using a self-controlled retrospective study that enrolled 59 patients with two failed cycles and treated with autologous PRP (three-dose scheme). The NHANES dataset was used to assess platelet changes during the menstrual cycle, using the mean platelet volume to platelet count ratio (MPR) index. The COSINOR packages for R were used to determine rhythmicity.

RESULTS

PRP treatments significantly improved the EMT (2.5 ± 1.4 mm, P<0.001), unaffected by obesity. After the PRP treatment, one patient spontaneously became pregnant; therefore, 58 patients underwent embryo transfer (62 cycles), of which in 39 cycles the embryos implanted (63.9%). This was a significant improvement from their previous cycle (vs. 22.6%, P<0.001). Clinical pregnancy also improved with the PRP treatment over the previous cycle (57.4% vs. 16.1%, P<0.001). When stratified by obesity, there was an appreciable decrease in embryo implantation and clinical pregnancy rates for the OW/OB group; nevertheless, the PRP treatment significantly improved embryo implantation and clinical pregnancy (P<0.05). A rhythm was observed with the MPR index (P<0.05) only for the NW group, suggesting that the platelets normally fluctuate during the menstrual cycle.

CONCLUSION

PRP improved embryo implantation and clinical pregnancy rates; however, these beneficial effects were attenuated by obesity. PRP presumptively promoted a change in the uterine environment to mimic the normal findings associated with normal-weight women.

Interleukin-37 contributes to endometrial regenerative cell-mediated immunotherapeutic effect on chronic allograft vasculopathy

BACKGROUND AIMS

Chronic allograft vasculopathy (CAV) remains a predominant contributor to late allograft failure after organ transplantation. Several factors have already been shown to facilitate the progression of CAV, and there is still an urgent need for effective and specific therapeutic approaches to inhibit CAV. Human mesenchymal-like endometrial regenerative cells (ERCs) are free from the deficiencies of traditional invasive acquisition methods and possess many advantages. Nevertheless, the exact immunomodulation mechanism of ERCs remains to be elucidated.

METHODS

C57BL/6 (B6) mouse recipients receiving BALB/c mouse donor abdominal aorta transplantation were treated with ERCs, negative control (NC)-ERCs and interleukin (IL)-37-/-ERCs (ERCs with IL-37 ablation), respectively. Pathologic lesions and inflammatory cell infiltration in the grafts, splenic immune cell populations, circulating donor-specific antibody levels and cytokine profiles were analyzed on postoperative day (POD) 40. The proliferative capacities of Th1, Th17 and Treg subpopulations were assessed in vitro.

RESULTS

Allografts from untreated recipients developed typical pathology features of CAV, namely endothelial thickening, on POD 40. Compared with untreated and IL-37-/-ERC-treated groups, IL-37-secreting ERCs (ERCs and NC-ERCs) significantly reduced vascular stenosis, the intimal hyperplasia and collagen deposition. IL-37-secreting ERCs significantly inhibited the proliferation of CD4+T cells, reduced the proportions of Th1 and Th17 cells, but increased the proportion of Tregs in vitro. Furthermore, in vitro results also showed that IL-37-secreting ERCs significantly inhibited Th1 and Th17 cell responses, abolished B-cell activation, diminished donor-specific antibody production and increased Treg proportions. Notably, IL-37-secreting ERCs remarkably downregulated the levels of pro-inflammatory cytokines (interferon-γ, tumor necrosis factor-α, IL-1β, IL-6 and IL-17A) and increased IL-10 levels in transplant recipients.

CONCLUSIONS

The knockdown of IL-37 dramatically abrogates the therapeutic ability of ERCs for CAV. Thus, this study highlights that IL-37 is indispensable for ERC-mediated immunomodulation for CAV and improves the long-term allograft acceptance.

Endometrium procurement and transplantation restores fertility in rats

RESEARCH QUESTION

Can rat endometrium be successfully procured and transplanted, and can a similar method be used to procure human endometrium?

DESIGN

Rat endometrium was procured using an endometrium stripping method and transplanted into female Sprague-Dawley rats. Macroscopic and histological changes, endometrial receptivity-related protein concentrations and fertility were assessed. Additionally, a preliminary experiment was conducted to procure human endometrium using a similar method.

RESULTS

Endometrium was successfully procured from both rats and humans, which contained intact endometrium and parts of the adjacent inner annulus myometrium. Endometrium auto-transplantation was conducted in rats and the procedure lasted a total of 41.3 ± 5.7 min with a mean blood loss of 0.09 ± 0.04 g. The transplanted endometrium survived well, but a fibrotic zone formed between the transplant and recipient tissue. Compared with sham rats, those with endometrium transplantation had similar endometrial thickness and endometrial gland numbers but reduced vascular density at 8 weeks after surgery. Endometrium transplantation also retained expression of the endometrial receptivity-related proteins leukaemia inhibitory factor and vascular endothelial growth factor. In contrast to non-pregnancy in the stripped horn, a mean of 5.0 ± 2.7 fetuses developed in the transplanted horn, and full-term live fetuses were conceived in the horns with transplanted endometrium.

CONCLUSIONS

Endometrium procurement by stripping method can obtain an intact and functional endometrium, and endometrium transplantation can reconstruct the uterine cavity and restore fertility in rats.

VitroGel-loaded human MenSCs promote endometrial regeneration and fertility restoration

Introduction: Intrauterine adhesions (IUA), also known as Asherman's syndrome, is caused by trauma to the pregnant or non-pregnant uterus, which leads to damaged endometrial basal lining and partial or total occlusion of the uterine chambers, resulting in abnormal menstruation, infertility, or recurrent miscarriage. The essence of this syndrome is endometrial fibrosis. And there is no effective treatment for IUA to stimulate endometrial regeneration currently. Recently, menstrual blood-derived stem cells (MenSCs) have been proved to hold therapeutic promise in various diseases, such as myocardial infarction, stroke, diabetes, and liver cirrhosis. Methods: In this study, we examined the effects of MenSCs on the repair of uterine adhesions in a rat model, and more importantly, promoted such therapeutic effects via a xeno-free VitroGel MMP carrier. Results: This combined treatment reduced the expression of inflammatory factors, increased the expression of anti-inflammatory factors, restricted the area of endometrial fibrosis, diminished uterine adhesions, and partially restored fertility, showing stronger effectiveness than each component alone and almost resembling the sham group. Discussion: Our findings suggest a highly promising strategy for IUA treatment.

MALAT1/miR-7-5p/TCF4 Axis Regulating Menstrual Blood Mesenchymal Stem Cells Improve Thin Endometrium Fertility by the Wnt Signaling Pathway

Thin endometrium (TE) is a significant factor contributing to fertility challenges, and addressing this condition remains a central challenge in reproductive medicine. Menstrual blood-derived mesenchymal stem cells (MenSCs) play a crucial role in tissue repair and regeneration, including that of TE. The Wnt signaling pathway, which is highly conserved and prevalent in eukaryotes, is essential for cell proliferation, tissue development, and reproductive functions. MALAT1 is implicated in various transcriptional and molecular functions, including cell proliferation and metastasis. However, the combined effects of the Wnt signaling pathway and the long non-coding RNA (lncRNA) MALAT1 on the regulation of MenSCs' regenerative capabilities in tissue engineering have not yet been explored. To elucidate the regulatory mechanism of MALAT1 in TE, we analyzed its expression levels in normal endometrium and TE tissues, finding that low expression of MALAT1 was associated with poor clinical prognosis. In addition, we conducted both in vitro and in vivo functional assays to examine the role of the MALAT1/miR-7-5p/TCF4 axis in cell proliferation and migration. Techniques such as dual-luciferase reporter assay, fluorescent in situ hybridization, and immunoblot experiments were utilized to clarify the molecular mechanism. To corroborate these findings, we established a TE model and conducted pregnancy experiments, demonstrating a strong association between MALAT1 expression and endometrial fertility. In conclusion, our comprehensive study provides strong evidence supporting that lncRNA MALAT1 modulates TCF4 expression in the Wnt signaling pathway through interaction with miR-7-5p, thus enhancing MenSCs-mediated improvement of TE and improving fertility.

Photobiomodulation therapy at 632 nm wavelength ameliorates intrauterine adhesion via activation of cAMP/PKA/CREB pathway

Intrauterine adhesion (IUA), a major cause of uterine infertility, is pathologically characterized by endometrial fibrosis. Current treatments for IUA have poor efficacy with high recurrence rate, and restoring uterine functions is difficult. We aimed to determine the therapeutic efficacy of photobiomodulation (PBM) therapy on IUA and elucidate its underlying mechanisms. A rat IUA model was established via mechanical injury, and PBM was applied intrauterinely. The uterine structure and function were evaluated using ultrasonography, histology, and fertility tests. PBM therapy induced a thicker, more intact, and less fibrotic endometrium. PBM also partly recovered endometrial receptivity and fertility in IUA rats. A cellular fibrosis model was then established with human endometrial stromal cells (ESCs) cultured in the presence of TGF-β1. PBM alleviated TGF-β1-induced fibrosis and triggered cAMP/PKA/CREB signaling in ESCs. Pretreatment with the inhibitors targeting this pathway weakened PBM's protective efficacy in the IUA rats and ESCs. Therefore, we conclude that PBM improved endometrial fibrosis and fertility via activating cAMP/PKA/CREB signaling in IUA uterus. This study sheds more lights on the efficacy of PBM as a potential treatment for IUA.

Value of Intrauterine Autologous Platelet-Rich Plasma Therapy on Endometrial Receptivity: A Literature Review

Endometrial receptivity is an important factor that influences embryo implantation. Thus, it is important to identify an applicable approach to improve endometrial receptivity in women undergoing assisted reproductive technology. Recently, growing evidence has indicated that intrauterine platelet-rich plasma (PRP) infusion is an effective method to obtain a satisfactory reproductive outcome by increasing endometrial thickness and improving endometrial receptivity. Therefore, the present review aims to outline the possible mechanisms of PRP on endometrial receptivity and summarize the present literature on the effects of PRP therapy in improving endometrial receptivity.

MenSCs Transplantation Improve the Viability of Injured Endometrial Cells Through Activating PI3K/Akt Pathway

Endometrial injury is one of the leading causes of female infertility and is caused by intrauterine surgery, endometrial infection, repeated abortion, or genital tuberculosis. Currently, there is little effective treatment to restore the fertility of patients with severe intrauterine adhesions and thin endometrium. Recent studies have confirmed the promising therapeutic effects of mesenchymal stem cell transplantation on various diseases with definite tissue injury. The aim of this study is to investigate the improvements of menstrual blood-derived endometrial stem cells (MenSCs) transplantation on functional restoration in the endometrium of mouse model. Therefore, ethanol-induced endometrial injury mouse models were randomly divided into two groups: the PBS-treated group, and the MenSCs-treated group. As expected, the endometrial thickness and gland number in the endometrium of MenSCs-treated mice were significantly improved compared to those of PBS-treated mice (P < 0.05), and fibrosis levels were significantly reduced (P < 0.05). Subsequent results revealed that MenSCs treatment significantly promoted angiogenesis in the injured endometrium. Simultaneously, MenSCs enhance the proliferation and antiapoptotic capacity of endometrial cells, which is likely contributed by activating the PI3K/Akt signaling pathway. Further tests also confirmed the chemotaxis of GFP-labeled MenSCs towards the injured uterus. Consequently, MenSCs treatment significantly improved the pregnant mice and the number of embryos in pregnant mice. This study confirmed the superior improvements of MenSCs transplantation on the injured endometrium and uncovered the potential therapeutic mechanism, which provides a promising alternative for patients with serious endometrial injury.

Exosomes derived from menstrual blood stromal cells ameliorated premature ovarian insufficiency and granulosa cell apoptosis by regulating SMAD3/AKT/MDM2/P53 pathway via delivery of thrombospondin-1

Premature ovarian insufficiency (POI) is clinically irreversible and seriously damages female fertility. We previously demonstrated that menstrual blood stromal cells (MenSCs)-derived exosomes (EXOs) effectively improved ovarian functions in the POI rat model. In this study, we investigated whether TSP1 is the key component in EXOs to ameliorate ovarian functions and further explored the molecular mechanism of EXOs in improving granulosa cell (GCs) activities. Our results demonstrated that knockdown TSP1 significantly debilitated the therapeutic effect of EXOs on estrous cyclicity, ovarian morphology, follicle numbers and pregnancy outcomes in 4-vinylcyclohexene diepoxide (VCD) induced POI rat model. In addition, EXOs treatment significantly promoted the activities and inhibited the apoptosis of VCD induced granulosa cells in vitro. Moreover, EXOs stimulation markedly activated the phosphorylation of SMAD3(Ser425) and AKT(Ser473), up-regulated the expressions of BCL2 and MDM2 as well as down-regulated the expressions of CASPASE3, CASPASE8, P53 and BAX. All these effects were supressed by SIS3, a inhibitor of TGF1/SMAD3. Our study revealed the key role of TSP1 in EXOs in improving POI pathology, restoring ovarian functions and GCs activities, andprovided a promising basis for EXOs in the treatment of ovarian dysfunction.

Treatment strategies for intrauterine adhesion: focus on the exosomes and hydrogels

Intrauterine adhesion (IUA), also referred to as Asherman Syndrome (AS), results from uterine trauma in both pregnant and nonpregnant women. The IUA damages the endometrial bottom layer, causing partial or complete occlusion of the uterine cavity. This leads to irregular menstruation, infertility, or repeated abortions. Transcervical adhesion electroreception (TCRA) is frequently used to treat IUA, which greatly lowers the prevalence of adhesions and increases pregnancy rates. Although surgery aims to disentangle the adhesive tissue, it can exacerbate the development of IUA when the degree of adhesion is severer. Therefore, it is critical to develop innovative therapeutic approaches for the prevention of IUA. Endometrial fibrosis is the essence of IUA, and studies have found that the use of different types of mesenchymal stem cells (MSCs) can reduce the risk of endometrial fibrosis and increase the possibility of pregnancy. Recent research has suggested that exosomes derived from MSCs can overcome the limitations of MSCs, such as immunogenicity and tumorigenicity risks, thereby providing new directions for IUA treatment. Moreover, the hydrogel drug delivery system can significantly ameliorate the recurrence rate of adhesions and the intrauterine pregnancy rate of patients, and its potential mechanism in the treatment of IUA has also been studied. It has been shown that the combination of two or more therapeutic schemes has broader application prospects; therefore, this article reviews the pathophysiology of IUA and current treatment strategies, focusing on exosomes combined with hydrogels in the treatment of IUA. Although the use of exosomes and hydrogels has certain challenges in treating IUA, they still provide new promising directions in this field.

P65 mediated UBR4 in exosomes derived from menstrual blood stromal cells to reduce endometrial fibrosis by regulating YAP Ubiquitination

BACKGROUND

Intrauterine adhesion (IUA) is a recurrent and refractory reproductive dysfunction disorder for which menstrual blood-derived stromal cells (MenSCs) might be a promising intervention. We reported that administration of MenSCs-derived exosomes (MenSCs-EXO) could achieve similar therapeutic effects to MenSCs transplantation, including alleviating endometrial fibrosis and improving fertility in IUA rats. The mass spectrometry sequencing result suggested that UBR4, a member of the proteasome family, was abundantly enriched in MenSCs-EXO. This study aimed to investigate the key role of UBR4 in MenSCs-EXO for the treatment of IUA and the specific molecular mechanism.

RESULTS

UBR4 was lowly expressed in the endometrial stromal cells (EndoSCs) of IUA patients. MenSCs-EXO treatment could restore the morphology of IUA endometrium, reduce the extent of fibrosis, and promote endometrial and vascular proliferation. Knockdown of UBR4 in MenSCs did not affect the characteristics of exosomes but attenuated the therapeutic effect of exosomes. UBR4 in MenSCs-EXO could alleviate endometrial fibrosis by boosting YAP ubiquitination degradation and promoting YAP nuclear-cytoplasmic translocation. Moreover, P65 could bind to the UBR4 promoter region to transcriptionally promote the expression level of UBR4 in MenSCs.

CONCLUSION

Our study clarified that MenSCs-EXO ameliorated endometrial fibrosis in IUA primarily by affecting YAP activity mediated through UBR4, while inflammatory signaling P65 may affect UBR4 expression in MenSCs to enhance MenSCs-EXO therapeutic effects. This revealed a novel mechanism for the treatment of IUA with MenSCs-EXO, proposing a potential option for the clinical treatment of endometrial injury.

Platelet-rich fibrin improves repair and regeneration of damaged endometrium in rats

Purpose

Intrauterine adhesion (IUA) is the most common cause of uterine infertility. This study aims to evaluate whether platelet-rich fibrin (PRF) treatment can stimulate damaged endometrium regeneration in rats.

Methods

First, hematoxylin and eosin (HE) staining, scanning and transmission electron microscopy, and ELISAs were used to evaluate the microstructure of PRF. Then, mechanical damage was used to establish an IUA rat model. A total of 40 SD female rats were randomized to three groups: PRF transplantation group, IUA group, and sham group. Rats were sacrificed at 3, 7, and 14 days and uteruses were obtained for further analysis. Finally, functional and histological recovery of the damaged endometrium was analyzed by pregnancy test, HE staining, Masson's staining, and immunohistochemistry.

Results

PRF has two distinct zones, platelets and fibrin zone. Long and narrow fibrin fibers interconnected with each other and formed a three-dimensional, flexible, and elastic structure; platelet aggregates were trapped in fibrin fibers, and each platelet is associated with several fibrin fibers. PRF exudates promoted endometrial stromal cell proliferation and migration in vitro. PRF transplantation was beneficial for maintaining uterine structure, promoting endometrial luminal epithelium and endometrial gland regeneration, and decreasing fibrotic areas in vivo.

Conclusion

Intrauterine administration of PRF was demonstrated to be effective in preventing IUA and stimulating damaged endometrium regeneration in rats. This study not only provided a promising method for its potential in endometrial regeneration in women who suffer from uterine infertility but also may prevent IUA after intrauterine surgery in clinical cases.

Research trends on platelet-rich plasma in the treatment of wounds during 2002-2021: A 20-year bibliometric analysis

Platelet-rich plasma (PRP) has attracted attention because of its potential to accelerate the wound healing process. However, resources for evaluating research trends in the treatment of wounds with PRP were limited. In this study, we aimed to make a bibliometric analysis of the literature related to PRP in the treatment of wounds and explore the research status, hotspots and frontiers in this field in recent 20 years. Studies about PRP treatment for wounds from 2002 to 2021 were retrieved from the Science Citation Index Expanded (SCI-E) of Web of Science (WOS) database. Visualisation softwares such as VOSviewer and SCImago Graphica, and CiteSpace were used to analyse the research trends and features. A total of 1748 studies were identified in the SCI-Expanded from 2002 to 2021. The number of publications on PRP in the treatment of wounds has shown an increasing trend, from 6 (in 2002) to 228 (in 2021). The papers published in the United States have led in times cited (14637) and H-index (63). Though Italy was slightly lower than China in the number of publications, the H-index and average cited (47, 28.45) were higher than that of China (38, 27.01). The strongest keyword was "fibrin" (strength = 13.07), and the longest burst duration keyword was "thrombin" (began in 2002 and ended in 2014). The largest 10 co-citation clusters are as follows: endothelial cell proliferation (#0), regenerative medicine-associated treatment (#1), diabetic wound healing (#2), autologous derived (#3), platelet-rich fibrin (#4), tissue engineering (#5), regenerative potential (#6), clinical randomised trial (#7), histologic observation (#8), and wound bacteria (#9). The United States has made the most outstanding contribution in this field. Chinese researchers need to enhance the quality of publications further. Wound Repair Regen. is the most noteworthy journal. The mechanism of growth factors of PRP, combination therapy, preparation of PRP, and related clinical trials may be topics that need attention.

PDGFBB improved the biological function of menstrual blood-derived stromal cells and the anti-fibrotic properties of exosomes

BACKGROUND

Intrauterine adhesion (IUA) is a reproductive dysfunction disease characterized by endometrial fibrosis, with limited therapeutic options and poor prognosis. Our previous studies confirmed that menstrual blood-derived stromal cells (MenSCs) effectively attenuated endometrial fibrosis in an animal model of IUA mainly through exosomes. This therapeutic effect can be enhanced by platelet-rich plasma (PRP), in which PDGFBB is an abundant growth factor. Therefore, we aimed to compare the effects of PRP and PDGFBB on the biological activities of MenSCs in vitro, and to further investigate the molecular mechanism of MenSCs-derived exosomes in alleviating endometrial fibrosis.

METHODS

MenSCs were isolated for in vitro functional assays to examine the viability, migration, and stemness of MenSCs. Endometrial stromal cells (EndoSCs) were treated with 50 ug/ml of MenSCs-derived exosomes, obtained by differential ultracentrifugation extraction. The molecular mechanisms by which PDGFBB improves MenSCs and exosomes alleviate EndoSCs fibrosis were then explored using immunofluorescence, western blot, and co-immunoprecipitation.

RESULTS

Both 100 ng/ml PDGFBB and 10% activated PRP promoted the proliferation, increased the S phase of cell cycle, and inhibited apoptosis of MenSCs in vitro. Compared with PRP, PDGFBB significantly promoted MenSCs migration. All of these effects were inhibited by sorafenib, a PDGFR-β inhibitor. PRP and PDGFBB activated AKT/NF-κB signaling pathway in MenSCs and increased the expression of P65 and OCT4. Moreover, pretreatment of PDGFBB did not increase the secretion of MenSCs but significantly increased the anti-fibrosis effects of MenSCs-derived exosomes on IUA-EndoSCs. MenSCs-derived exosomes attenuated SMAD3 phosphorylation and increased YAP ubiquitination, which reduced the binding of YAP/SMAD3. Pretreatment with PDGFBB amplified this effect.

CONCLUSIONS

In summary, PDGFBB could improve the biological functions of MenSCs via AKT/NF-κB signaling pathway, including viability, migration, and stemness. Our results indicated that PDGFBB amplified MenSCs-derived exosomes to attenuate endometrial fibrosis by inhibiting YAP activity, revealing a novel mechanism by which PRP enhanced the ability of MenSCs to repair tissue injury and providing a potential option for improving stem cell efficacy in IUA.

MALAT1 participates in the role of platelet-rich plasma exosomes in promoting wound healing of diabetic foot ulcer

Exosomes isolated from platelet-rich plasma (PRP-exos) have been recently deemed as an optimized therapeutic strategy in Diabetic foot ulcer (DFU) treatment. Herein, we aimed to explore whether MALAT1 participates in DFU wound healing by PRP-exos treatment and the related preliminary mechanism. Fibroblasts were isolated from healthy donors and DFU patients, and the expression of MALAT1, miR-374a-3p and DNMT3A were detected by RT-PCR. The effect of MALAT1 and miR-374a-3p on DFU fibroblast function was verified by gain/loss of function experiment. The targeted binding of MALAT and miRNA was verified by double luciferase reporter gene assay. PRP-exos were isolated from normal human blood and characterized, and then co-cultured with DFU fibroblasts. The MALAT1 expression was donwregulated while the miR-374a-5p expression was upregulated in DFU fibroblasts. Double luciferase reporter gene assay demonstrated the targeted binding of MALAT and miR-374a-5p. Overexpression of MALAT1 or knockdown of miR-374a-5p could increase viability and inhibit apoptosis and pyroptosis of DFU fibroblast. And overexpression of miR-374a-5p reversed the effect of PRR-exos or MALAT1 overexpression on cell viability, apoptosis and pyroptosis. Collectively, MALAT1 mediated signal axis participates in the role of PRP-exos in promoting DFU wound healing, which may help identify optimal targets and effective therapies for DFU treatment.

How platelet-rich plasma (PRP) intra-uterine injection improve endometrial receptivity of intrauterine adhesions in women: A time-series-based self-controlled study

Platelet-rich plasma (PRP) treatment proven to improve fertility outcomes in patients with a poor endometrial environment. However, the mechanism is not yet clear. In this study, we recruited 6 patients with infertility due to IUA and 6 normal control women. The subjects in the IUA group collected samples before and after PRP treatment. Endometrial receptivity was improved after PRP treatment. After PRP treatment, the endometrial NK cells, CD8 T cells and Th1 cells were significantly lower than those before treatment. Functional enrichment analysis suggested that the effects of changes in microbial composition played an important role in changes in the endometrial immune environment. Among them, the most significant difference was Bacillus. Our self-controlled cohort in this study can fully describe the detailed mechanism by which PRP treatment improves the endometrial environment.

Human Menstrual Blood-Derived Endometrial Stem Cells Promote Functional Recovery by Improving the Inflammatory Microenvironment in a Mouse Spinal Cord Injury Model

Spinal cord injury (SCI) is a traumatic injury of the central nervous system. Because neurons are damaged and difficult to regenerate after SCI, its repair remains challenging. However, recent research on stem cell therapy have favored its use after SCI. In this study, based on the establishment of a mouse SCI model, human menstrual blood-derived endometrial stem cells (MenSCs) were intrathecally injected to explore the role and molecular mechanism of MenSCs in SCI. MenSCs were transplanted following SCI in the animal model, and behavioral evaluations showed that MenSC transplantation improved functional recovery. Therefore, samples were collected after 7 days, and transcriptome sequencing was performed. Gene Ontology (GO) enrichment analysis revealed that SCI is closely related to immune system processes. After transplantation of MenSCs, the immune response was significantly activated. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, MenSC transplantation was found to be closely related to Th1, Th2, and Th17 cell differentiation pathways. Neuronal damage and glial cell proliferation and activation in the different groups were detected by fluorescence immunohistochemistry and Western blotting 7 days after SCI. Simultaneously, the activation of different types of microglia was detected and the expression of pro-inflammatory and anti-inflammatory factors was quantitatively analyzed. The results showed that MenSC transplantation and sonic hedgehog (Shh)-induced MenSCs accelerated neuronal recovery at the injured site, inhibited the formation of glial cells and microglial activation at the injured site, inhibited the expression of inflammatory factors, and improved the inflammatory microenvironment to achieve functional recovery of SCI. This study provides an experimental basis for the study of the role and molecular mechanism of MenSCs in SCI repair, and a reference for the role of Shh-induced MenSCs in SCI repair.

Platelet-Rich Plasma Improves Pregnancy Outcomes in Moderate to Severe Intrauterine Adhesion: A Retrospective Cohort Study

The purpose of the present study was to investigate the therapeutic effects of platelet-rich plasma (PRP) in women with moderate to severe intrauterine adhesion (IUA). A retrospective cohort study was conducted at a reproductive medical center between July 2020 and June 2021 to compare the clinical pregnancy rate of two groups (PRP and non-PRP groups) after hysteroscopic adhesiolysis. A multivariate logistic regression analysis and propensity score matching (PSM) were performed to minimize potential bias. According to our inclusion and exclusion criteria, 133 patients were finally enrolled and divided into the PRP group (n = 48) and non-PRP group (n = 85). In the primary comparison, the clinical pregnancy rate in the PRP group was higher than that in the non-PRP group (41.7% vs. 28.2%, p = 0.114), albeit without statistical significance. Multivariate logistic regression analysis was performed, and the results of the adjusted model showed that PRP treatment significantly improved the clinical pregnancy rate (adjusted OR = 3.00, 95% CI = 1.22-7.38, p = 0.017). After PSM, the clinical pregnancy rate was higher in the PRP group than that in the non-PRP group (46.2% vs. 20.5%, p = 0.031). Based on the present study, we concluded that intrauterine perfusion of PRP had great potential in improving the clinical pregnancy rate in patients with moderate to severe IUA. Therefore, we recommend the application of PRP in the treatment of IUA.

Endometrial cell-derived conditioned medium in combination with platelet-rich plasma promotes the development of mouse ovarian follicles

Fertility preservation is one of the most important issues in assisted reproductive technology. Previous studies have shown that cytokines and growth factors can improve follicle growth. The endometrial stromal cells secrete various factors that are involved in maintaining the integrity of uterine and epithelial secretory function. The platelet-rich plasma contains a large assembly of platelets suspended in plasma that successfully improves the viability and growth of various cell lines. This work aimed to investigate the influences of conditioned medium (CM) and platelet-rich plasma (PRP) on the development of ovarian follicles in infertile mice due to cyclophosphamide (CYC) exposure. In this study, 65 healthy BALB/c female mice (∼28-30 g and 6-8 weeks old) in five groups were studied. Immunohistochemistry (IHC) was used to detect growth differentiation factor 9 (GDF9)-positive cells. The mRNA expression levels of SMAD1, SMAD2, and BMP15 was assessed using reverse transcription-polymerase chain reaction (RT-PCR) method. The expression levels of SMAD1, GDF9, BMP15, and SMAD2 in the CM+PRP group was significantly more than in the CM and PRP groups. In addition, live birth occurred in the CM+PRP group. Treatment with CM+PRP in infertile mice due to Cy exposure increased fertility and live-birth rate. In general, our study suggested that the CM and PRP combination could improve the growth of mice ovarian follicles in vivo.

Intraovarian condensed platelet cytokines for infertility and menopause-Mirage or miracle?

On a therapeutic landscape unchanged since the 1980's, oocyte donation with IVF still stands as the solitary medical answer to diminished reserve and premature ovarian insufficiency. In 2016, intraovarian platelet-rich plasma (PRP) crossed the horizon as a hopeful reply to these intertwined problems. The once remote mirage of platelet cytokine effects on gene regulation or telomere stabilization has been brought into sharper focus, with current work clarifying how PRP corrects oxidative stress, rectifies tissue hypoxia, downregulates apoptosis, and enhances cellular metabolism. Not yet ready for routine use, this innovative treatment has already offered at least one point of early consensus: How intraovarian PRP results should be classified-Patients are either responders or non-responders. From this it is intriguing that no published PRP protocol has ever reported a supranormal ovarian rebound or hyperstimulation effect. This might be explained by baseline age-related ovarian conditions prevalent among poor responders, but since dysregulated or malignant transformations are also missing in other tissue contexts following autologous PRP treatment, the contribution of some platelet product which intrinsically delimits regenerative action cannot be discounted. Here we summarize results with recent experimental and clinical platelet research, framing those most likely to help advance reproductive endocrinology practice.

Endometrial Stem Cells and Their Applications in Intrauterine Adhesion

Intrauterine adhesion (IUA), resulting from pregnancy or nonpregnant uterine trauma, is one of the major causes of abnormal menstruation, infertility, or repeated pregnancy loss. Although a few methods, including hysteroscopy and hormone therapy, are routinely used for its diagnosis and treatment, they cannot restore tissue regeneration. Stem cells, which have self-renewal and tissue regeneration abilities, have been proposed as a promising therapy for patients with severe IUAs. In this review, we summarize the origin and features of endometrium-associated stem cells and their applications in the treatment of IUAs based on animal models and human clinical trials. We expect that this information will help to elucidate the underlying mechanism for tissue regeneration and to improve the design of stem cell-based therapies for IUAs.

Strategies for modelling endometrial diseases

Each month during a woman's reproductive years, the endometrium undergoes vast changes to prepare for a potential pregnancy. Diseases of the endometrium arise for numerous reasons, many of which remain unknown. These endometrial diseases, including endometriosis, adenomyosis, endometrial cancer and Asherman syndrome, affect many women, with an overall lack of efficient or permanent treatment solutions. The challenge lies in understanding the complexity of the endometrium and the extensive changes, orchestrated by ovarian hormones, that occur in multiple cell types over the period of the menstrual cycle. Appropriate model systems that closely mimic the architecture and function of the endometrium and its diseases are needed. The emergence of organoid technology using human cells is enabling a revolution in modelling the endometrium in vitro. The goal of this Review is to provide a focused reference for new models to study the diseases of the endometrium. We provide perspectives on the power of new and emerging models, from organoids to microfluidics, which have opened up a new frontier for studying endometrial diseases.

Cell therapy for the treatment of reproductive diseases and infertility: an overview from the mechanism to the clinic alongside diagnostic methods

Infertility is experienced by 8%-12% of adults in their reproductive period globally and has become a prevalent concern. Besides routine therapeutic methods, stem cells are rapidly being examined as viable alternative therapies in regenerative medicine and translational investigation. Remarkable progress has been made in understanding the biology and purpose of stem cells. The affected pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) are further studied for their possible use in reproductive medicine, particularly for infertility induced by premature ovarian insufficiency and azoospermia. Accordingly, this study discusses current developments in the use of some kinds of MSCs such as adipose-derived stem cells, bone marrow stromal cells, umbilical cord MSCs, and menstrual blood MSCs. These methods have been used to manage ovarian and uterine disorders, and each technique presents a novel method for the therapy of infertility.

Efficacy of Autologous Intrauterine Infusion of Platelet-Rich Plasma in Patients with Unexplained Repeated Implantation Failures in Embryo Transfer: A Systematic Review and Meta-Analysis

(1) Background: Controversial conclusions have been made in previous studies regarding the influence of autologous platelet-rich plasma (PRP) in the reproductive outcomes of women with repeated implantation failures (RIF) who are undergoing embryo transfer (ET). (2) Methods: This study aimed to evaluate the effect of PRP intrauterine infusion in patients with unexplained RIF, who are undergoing in vitro fertilization (IVF) or intracytoplasmic injection (ICSI), by a systematic review and meta-analysis. (3) Results: A fixed-effects model was used, and 795 cases and 834 controls were included in these studies. The pooling of the results showed the beneficial effect of PRP which were compared with those of the control in terms of the clinical pregnancy rates (n = 10, risk ratio (RR) = 1.79, 95% confidence intervals (CI): 1.55, 2.06; p < 0.01, I2 = 40%), live birth rates (n = 4, RR = 2.92, 95% CI: 2.22, 3.85; p < 0.01, I2 = 83%), implantation rates (n = 3, RR = 1.74, 95% CI: 1.34, 2.26; p < 0.01, I2 = 0%), and positive serum β-HCG 14 days after the ET (n = 8, RR = 1.77, 95% CI: 1.54, 2.03; p < 0.01, I2 = 36%). However, we did not find that the miscarriage rates indicated a significant difference between the two groups (n = 6, RR = 1.04, 95% CI: 0.72, 1.51; p = 0.83, I2 = 0%). (4) Conclusions: The findings of this systemic review and meta-analysis suggest that PRP appears to improve the results of IVF/ICSI treatments in the cases of unexplained RIF.

Amniotic membrane extract-enriched hydrogel augments the therapeutic effect of menstrual blood-derived stromal cells in a rat model of intrauterine adhesion

We previously demonstrated that transplantation of menstrual blood-derived stromal cells (MenSCs) is a safe and effective therapy for treating intrauterine adhesions (IUA). However, improving the colonization and therapeutic efficiency of MenSCs is still needed before full clinical application. Here, we established an amniotic membrane extract (AME)-enriched RGD hydrogel, and evaluated the therapeutic effect of this adjuvant combined with MenSCs transplantation in an IUA rat model. Our results indicated that AME promoted the proliferation and secretion of MenSCs in vitro, up-regulated the expression of apoptosis-suppressing gene BCL2 and down-regulated the expression of apoptosis-related genes Caspase-3 and Caspase-8. The AME-enriched hydrogel was biocompatible, and improved the survival of MenSCs in vitro and in vivo. It also promoted the retention of MenSCs in IUA uterus and augmented the effects of MenSCs on improving uterus morphology, endometrial proliferation, endometrial receptivity and fibrosis suppression. In addition, co-transplantation of MenSCs with AME-enriched hydrogel markedly down-regulated the expressions of inflammation-related genes IL10 and TGFβ while up-regulated the IL4/IFN-γ ratio in the IUA endometrium, and improved the expressions of cell proliferation-related antigen, gland-regeneration-related marker leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5), angiogenesis-related marker platelet and endothelial cell adhesion molecule 1 (PECAM1), endometrial receptivity related genes ITGα5 and ITGβ3. Our study suggested that AME and MenSCs had a synergistic effect. Co-transplantation of MenSCs with AME-enriched hydrogel provided a promising approach for stem cell-based IUA treatment.

Mesenchymal stem cells to treat female infertility; future perspective and challenges: A review

Infertility negatively impacts the overall health and social life of affected individuals and couples. Female infertility is their inability to perceive pregnancy. To date, polycystic ovary syndrome, primary ovarian insufficiency, fallopian tube obstruction, endometriosis, and intrauterine synechiae have been identified as the primary causes of infertility in women. However, despite the mutual efforts of clinicians and research scientists, the development of an effective treatment modality has met little success in combating female infertility. Intriguingly, significant research has demonstrated mesenchymal stem cells as an optimal source for treating infertility disorders. Therefore, here we attempted to capsulize to date available studies to summarize the therapeutic potential of mesenchymal stem cells in combating infertility in women by focusing on the underlying mechanism through which stem cells can reduce the effects of ovarian disorders. Furthermore, we also discussed the preclinical and clinical application of stem cell therapy, their limitation, and the future perspective to minimize these limitations.

Stem Cells and Organs-on-chips: New Promising Technologies for Human Infertility Treatment

Having biological children remains an unattainable dream for most couples with reproductive failure or gonadal dysgenesis. The combination of stem cells with gene editing technology and organ-on-a-chip models provides a unique opportunity for infertile patients with impaired gametogenesis caused by congenital disorders in sex development or cancer survivors. But how will these technologies overcome human infertility? This review discusses the regenerative mechanisms, applications, and advantages of different types of stem cells for restoring gametogenesis in infertile patients, as well as major challenges that must be overcome before clinical application. The importance and limitations of in vitro generation of gametes from patient-specific human-induced pluripotent stem cells (hiPSCs) will be discussed in the context of human reproduction. The potential role of organ-on-a-chip models that can direct differentiation of hiPSC-derived primordial germ cell-like cells to gametes and other reproductive organoids is also explored. These rapidly evolving technologies provide prospects for improving fertility to individuals and couples who experience reproductive failure.

Recent Developments in Biomaterial-Based Hydrogel as the Delivery System for Repairing Endometrial Injury

Endometrial injury caused by intrauterine surgery often leads to pathophysiological changes in the intrauterine environment, resulting in infertility in women of childbearing age. However, clinical treatment strategies, especially for moderate to severe injuries, often fail to provide satisfactory therapeutic effects and pregnancy outcomes. With the development of reproductive medicine and materials engineering, researchers have developed bioactive hydrogel materials, which can be used as a physical anti-adhesion barrier alone or as functional delivery systems for intrauterine injury treatment by loading stem cells or various active substances. Studies have demonstrated that the biomaterial-based hydrogel delivery system can provide sufficient mechanical support and improve the intrauterine microenvironment, enhance the delivery efficiency of therapeutic agents, prolong intrauterine retention time, and perform efficiently targeted repair compared with ordinary drug therapy or stem cell therapy. It shows the promising application prospects of the hydrogel delivery system in reproductive medicine. Herein, we review the recent advances in endometrial repair methods, focusing on the current application status of biomaterial-based hydrogel delivery systems in intrauterine injury repair, including preparation principles, therapeutic efficacy, repair mechanisms, and current limitations and development perspectives.

Human Platelet-Rich Plasma Facilitates Angiogenesis to Restore Impaired Uterine Environments with Asherman’s Syndrome for Embryo Implantation and Following Pregnancy in Mice

Asherman’s syndrome (AS) is caused by intrauterine adhesions and inactive endometrium from repeated curettage of the uterine endometrium. AS is a major cause of recurrent implantation failure and miscarriage and is very difficult to treat because of the poor recovery of endometrial basal cells. Platelet-rich plasma (PRP) has abundant growth factors that may induce angiogenesis and cell proliferation. Here, we demonstrate that human PRP (hPRP) significantly enhances angiogenesis to restore embryo implantation, leading to successful pregnancy in mice with AS. In mice with AS, hPRP treatment considerably reduced the expression of fibrosis markers and alleviated oligo/amenorrhea phenotypes. Mice with AS did not produce any pups, but the hPRP therapy restored their infertility. AS-induced abnormalities, such as aberrantly delayed embryo implantation and intrauterine growth retardation, were considerably eliminated by hPRP. Furthermore, hPRP significantly promoted not only the elevation of various angiogenic factors, but also the migration of endometrial stromal cells. It also increased the phosphorylation of STAT3, a critical mediator of wound healing, and the expression of tissue remodeling genes in a fibrotic uterus. PRP could be a promising therapeutic strategy to promote angiogenesis and reduce fibrosis in impaired uterine environments, leading to successful embryo implantation for better clinical outcomes in patients with AS.

Therapeutic Potential of Menstrual Blood-Derived Stem Cell Transplantation for Intrauterine Adhesions

An increasing number of women experience intrauterine adhesion as a result of intrauterine operations, such as induced abortion, which can cause infertility, recurrent abortion and amenorrhea. Although some strategies have been applied clinically, such as hysteroscopy adhesiolysis of intrauterine adhesions, the results have not been promising. As regenerative medicine develops, research on menstrual blood-derived stem cell transplantation is increasing due to the properties of these cells, including self-renewal, differentiation, angiogenesis, anti-inflammation and immunomodulation. As a result, menstrual blood-derived stem cells may be an ideal cell source for the treatment of intrauterine adhesion. Excitingly, it has been reported that autologous menstrual blood stem cells could recovery injured endometrium and improve infertility in patients with refractory intrauterine adhesion. In this review, we discuss the possible potential of menstrual blood-derived stem cell transplantation for intrauterine adhesion, including the antifibrosis, angiogenesis, anti-inflammation and immunoregulation properties of the cells, which brings hopes for clinical therapy.

Extracorporeal Shock Wave Therapy Combined with Platelet-Rich Plasma during Preventive and Therapeutic Stages of Intrauterine Adhesion in a Rat Model

Intrauterine adhesion (IUA) is caused by artificial endometrial damage during intrauterine cavity surgery. The typical phenotype involves loss of spontaneous endometrium recovery and angiogenesis. Undesirable symptoms include abnormal menstruation and infertility; therefore, prevention and early treatment of IUA remain crucial issues. Extracorporeal shockwave therapy (ESWT) major proposed therapeutic mechanisms include neovascularization, tissue regeneration, and fibrosis. We examined the effects of ESWT and/or platelet-rich plasma (PRP) during preventive and therapeutic stages of IUA by inducing intrauterine mechanical injury in rats. PRP alone, or combined with ESWT, were detected an increased number of endometrial glands, elevated vascular endothelial growth factor protein expression (hematoxylin-eosin staining and immunohistochemistry), and reduced fibrosis rate (Masson trichrome staining). mRNA expression levels of nuclear factor-kappa B, tumor necrosis factor-α, transforming growth factor-β, interleukin (IL)-6, collagen type I alpha 1, and fibronectin were reduced during two stages. However, PRP alone, or ESWT combined with PRP transplantation, not only increased the mRNA levels of vascular endothelial growth factor (VEGF) and progesterone receptor (PR) during the preventive stage but also increased PR, insulin-like growth factor 1 (IGF-1), and IL-4 during the therapeutic stage. These findings revealed that these two treatments inhibited endometrial fibrosis and inflammatory markers, thereby inhibiting the occurrence and development of intrauterine adhesions.

EndMT: New findings on the origin of myofibroblasts in endometrial fibrosis of intrauterine adhesions

BACKGROUND

Intrauterine adhesion (IUA) is one of the leading causes of infertility and the main clinical challenge is the high recurrence rate. The key to solving this dilemma lies in elucidating the mechanisms of endometrial fibrosis. The aim of our team is to study the mechanism underlying intrauterine adhesion fibrosis and the origin of fibroblasts in the repair of endometrial fibrosis.

METHODS

Our experimental study involving an animal model of intrauterine adhesion and detection of fibrosis-related molecules. The levels of molecular factors related to the endothelial-to-mesenchymal transition (EndMT) were examined in a rat model of intrauterine adhesion using immunofluorescence, immunohistochemistry, qPCR and Western blot analyses. Main outcome measures are levels of the endothelial marker CD31 and the mesenchymal markers alpha-smooth muscle actin (α-SMA) and vimentin.

RESULTS

Immunofluorescence co-localization of CD31 and a-SMA showed that 14 days after moulding, double positive cells for CD31 and a-SMA could be clearly observed in the endometrium. Decreased CD31 levels and increased α-SMA and vimentin levels indicate that EndMT is involved in intrauterine adhesion fibrosis.

CONCLUSIONS

Endothelial cells promote the emergence of fibroblasts via the EndMT during the endometrial fibrosis of intrauterine adhesions.

Estimates of global research productivity in primary ovarian insufficiency from 2000 to 2021: Bibliometric analysis

BACKGROUND

Primary ovarian insufficiency (POI) is a heterogeneous disease with diverse clinical phenotypes and etiologies, which is defined as ovarian dysfunction under the age of 40 years. The global prevalence of POI is approximately about 1.1%, and it severely affects female fertility. Nevertheless, bibliometric analysis in this field is extremely limited. We aimed to visualize the research hotspots and trends of POI using bibliometric analysis and tried to predict the future development of this field.

METHODS

The original articles regarding POI were culled from the Web of Science Core Collection. Countries, institutions, journals, authors, and keywords in this field were visually analyzed by employing CiteSpace software and Microsoft Excel 2021 software.

RESULTS

A total of 2,999 publications were included for further bibliometric analysis after screening the titles and abstracts stringently. The number of literature regarding POI significantly increased yearly. These publications come from 78 countries. The USA was dominant in the field of POI in terms of the number of publications (865), average citations per item (57.36), and h-index (112). The Institut National De La Sante Et De La Recherche Medicale Inserm is the most high-yield institution in this field with 351 publications. Fertility and Sterility ranked first with the highest number of publications (152), followed by Human Reproduction (138). According to the keyword cluster analysis from 2000 to 2021, the eight keyword clusters encountered frequently were apoptosis, osteoporosis, fertility preservation, mutation, fragile x syndrome, adrenal insufficiency, DNA repair, ovarian reserve. Keyword citation burst analysis revealed that whole-exome sequencing, ovarian tissue cryopreservation, and DNA repair had a citation burst until 2021.

CONCLUSIONS

Great progress has been made in POI research over the past 20 years, which is widely researched but unevenly developed in the world. In terms of influence, the United States may be in the lead. The research hotspots in POI are mainly pathogenesis and treatment, including genetic mutation, hormone therapy, fertility preservation, and stem cell transplantation.

Understanding menstrual blood-derived stromal/stem cells: Definition and properties. Are we rushing into their therapeutic applications?

Cells with mesenchymal stem cell properties have been identified in menstrual blood and termed menstrual blood-derived stem/stromal cells (MenSCs). MenSCs have been proposed as ideal candidates for cell-based therapy in regenerative medicine and immune-related diseases. However, MenSCs identity has been loosely defined so far and there is controversy regarding their cell markers and differentiation potential. In this review, we outline the origin of MenSCs in the context of regenerating human endometrium, with attention to endometrial eMSCs as reference cells to understand MenSCs. We summarize the cell identity markers analyzed and the immunomodulatory and reparative properties reported. We also address the recent use of MenSCs in cell reprogramming. The main goal of this review is to contribute to the understanding of the identity and properties of MenSCs as well as to identify potential caveats and new venues that deserve to be explored to strengthen their potential applications.

Tropoelastin improves adhesion and migration of intra-articular injected infrapatellar fat pad MSCs and reduces osteoarthritis progression

Intra-articular injection of mesenchymal stem cells (MSCs) is a promising strategy for osteoarthritis (OA) treatment. However, more and more studies reveal that the injected MSCs have poor adhesion, migration, and survival in the joint cavity. A recent study shows that tropoelastin (TE) regulates adhesion, proliferation and phenotypic maintenance of MSCs as a soluble additive, indicating that TE could promote MSCs-homing in regenerative medicine. In this study, we used TE as injection medium, and compared it with classic media in MSCs intra-articular injection such as normal saline (NS), hyaluronic acid (HA), and platelet-rich plasma (PRP). We found that TE could effectively improve adhesion, migration, chondrogenic differentiation of infrapatellar fat pad MSCs (IPFP-MSCs) and enhance matrix synthesis of osteoarthritic chondrocytes (OACs) in indirect-coculture system. Moreover, TE could significantly enhance IPFP-MSCs adhesion via activation of integrin β1, ERK1/2 and vinculin (VCL) in vitro. In addition, intra-articular injection of TE-IPFP MSCs suspension resulted in a short-term increase in survival rate of IPFP-MSCs and better histology scores of rat joint tissues. Inhibition of integrin β1 or ERK1/2 attenuated the protective effect of TE-IPFP MSCs suspension in vivo. In conclusion, TE promotes performance of IPFP-MSCs and protects knee cartilage from damage in OA through enhancement of cell adhesion and activation of integrin β1/ERK/VCL pathway. Our findings may provide new insights in MSCs intra-articular injection for OA treatment.

Making More Womb: Clinical Perspectives Supporting the Development and Utilization of Mesenchymal Stem Cell Therapy for Endometrial Regeneration and Infertility

The uterus is a homeostatic organ, unwavering in the setting of monthly endometrial turnover, placental invasion, and parturition. In response to ovarian steroid hormones, the endometrium autologously prepares for embryo implantation and in its absence will shed and regenerate. Dysfunctional endometrial repair and regeneration may present clinically with infertility and abnormal menses. Asherman's syndrome is characterized by intrauterine adhesions and atrophic endometrium, which often impacts fertility. Clinical management of infertility associated with abnormal endometrium represents a significant challenge. Endometrial mesenchymal stem cells (MSC) occupy a perivascular niche and contain regenerative and immunomodulatory properties. Given these characteristics, mesenchymal stem cells of endometrial and non-endometrial origin (bone marrow, adipose, placental) have been investigated for therapeutic purposes. Local administration of human MSC in animal models of endometrial injury reduces collagen deposition, improves angiogenesis, decreases inflammation, and improves fertility. Small clinical studies of autologous MSC administration in infertile women with Asherman's Syndrome suggested their potential to restore endometrial function as evidenced by increased endometrial thickness, decreased adhesions, and fertility. The objective of this review is to highlight translational and clinical studies investigating the use of MSC for endometrial dysfunction and infertility and to summarize the current state of the art in this promising area.

Mesenchymal stem cells therapy: A promising method for the treatment of uterine scars and premature ovarian failure

Both intrauterine adhesions (IUA) and premature ovarian failure (POF) have plagued women all over the world for a long time. It is well known that all invasive operations involving the uterus can disrupt its structural and functional integrity to a varying degree, which inevitably lead to abnormal scar formation, such as IUA, also known as Asherman's syndrome with symptoms like hypomenorrhea or infertility. Another reproductive disorder that causes infertility is primary ovarian insufficiency (POI) or POF, which is a degenerative phenomenon in the ovary among women under the age of 40. In recent years, various types of stem cells, especially mesenchymal stem cells (MSCs) have been widely used in reproductive medicine due to their properties, such as immunoregulation, anti-inflammation, angiogenesis, anti-apoptosis, and trophicity. However, the extensive clinical application of cell therapy is impeded by their safety, cost, and manufacturing. In this review, we sought to summarize the recent advances in using different types of MSCs in treating uterine scars and POF. We also describe several biological pathways and molecules involved in animal studies and clinical application; extracellular vesicles secreted by MSCs may be a promising attractive tool to ensure the treatment of infertility by restoring normal reproductive function.

Stem cell-based therapy for ameliorating intrauterine adhesion and endometrium injury

Intrauterine adhesion refers to endometrial repair disorders which are usually caused by uterine injury and may lead to a series of complications such as abnormal menstrual bleeding, recurrent abortion and secondary infertility. At present, therapeutic approaches to intrauterine adhesion are limited due to the lack of effective methods to promote regeneration following severe endometrial injury. Therefore, to develop new methods to prevent endometrial injury and intrauterine adhesion has become an urgent need. For severely damaged endometrium, the loss of stem cells in the endometrium may affect its regeneration. This article aimed to discuss the characteristics of various stem cells and their applications for uterine tissue regeneration.

Endometrial stem/progenitor cells and their roles in immunity, clinical application, and endometriosis

Endometrial stem/progenitor cells have been proved to exist in periodically regenerated female endometrium and can be divided into three categories: endometrial epithelial stem/progenitor cells, CD140b+CD146+ or SUSD2+ endometrial mesenchymal stem cells (eMSCs), and side population cells (SPs). Endometrial stem/progenitor cells in the menstruation blood are defined as menstrual stem cells (MenSCs). Due to their abundant sources, excellent proliferation, and autotransplantation capabilities, MenSCs are ideal candidates for cell-based therapy in regenerative medicine, inflammation, and immune-related diseases. Endometrial stem/progenitor cells also participate in the occurrence and development of endometriosis by entering the pelvic cavity from retrograde menstruation and becoming overreactive under certain conditions to form new glands and stroma through clonal expansion. Additionally, the limited bone marrow mesenchymal stem cells (BMDSCs) in blood circulation can be recruited and infiltrated into the lesion sites, leading to the establishment of deep invasive endometriosis. On the other hand, cell derived from endometriosis may also enter the blood circulation to form circulating endometrial cells (CECs) with stem cell-like properties, and to migrate and implant into distant tissues. In this manuscript, by reviewing the available literature, we outlined the characteristics of endometrial stem/progenitor cells and summarized their roles in immunoregulation, regenerative medicine, and endometriosis, through which to provide some novel therapeutic strategies for reproductive and cancerous diseases.

Application of Stem Cell Therapy for Infertility

Infertility creates an immense impact on the psychosocial wellbeing of affected couples, leading to poor quality of life. Infertility is now considered to be a global health issue affecting approximately 15% of couples worldwide. It may arise from factors related to the male (30%), including varicocele, undescended testes, testicular cancer, and azoospermia; the female (30%), including premature ovarian failure and uterine disorders; or both partners (30%). With the recent advancement in assisted reproduction technology (ART), many affected couples (80%) could find a solution. However, a substantial number of couples cannot conceive even after ART. Stem cells are now increasingly being investigated as promising alternative therapeutics in translational research of regenerative medicine. Tremendous headway has been made to understand the biology and function of stem cells. Considering the minimum ethical concern and easily available abundant resources, extensive research is being conducted on induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSC) for their potential application in reproductive medicine, especially in cases of infertility resulting from azoospermia and premature ovarian insufficiency. However, most of these investigations have been carried out in animal models. Evolutionary divergence observed in pluripotency among animals and humans requires caution when extrapolating the data obtained from murine models to safely apply them to clinical applications in humans. Hence, more clinical trials based on larger populations need to be carried out to investigate the relevance of stem cell therapy, including its safety and efficacy, in translational infertility medicine.

Stem Cell-Based Therapy for Asherman Syndrome: Promises and Challenges

Asherman syndrome (AS) has an adverse effect on reproductive health and fertility by affecting endometrial regeneration. Stem cell-based therapies hold promise for future use in activating non-functional endometrium and reconstructing the endometrium in vivo. It has been postulated that various endometrial stem cells (EnSCs) are responsible for endometrial regeneration. Numerous studies have focused on bone marrow-derived stem cells (BMDSCs), which may provide new ideas for repairing endometrial lesions and reconstructing the endometrium. Other sources of stem cells, such as menstrual blood, umbilical cord, and amniotic membrane, have also attracted much attention as candidates for transplantation in AS. This review discusses the features and specific biomarkers among four types of resident endometrial stem cells, applications of four different sources of exogenous stem cells in AS, and development of stem cell therapy using biomaterials and exosomes.

Use of Intra-uterine Injection of Platelet-rich Plasma (PRP) for Endometrial Receptivity and Thickness: a Literature Review of the Mechanisms of Action

Endometrial receptivity and thickness play an important role in achieving a pregnancy. Intrauterine autologous platelet-rich plasma (PRP) infusion has been used in infertile women with recurrent implantation failure (RIF) and thin endometrial lining thickness (EMT). Literature search was performed in PubMed for studies including in vitro, animal, and human studies as well as in abstracts presented at national conferences. Animal studies demonstrated a decrease in the expression of inflammatory markers and fibrosis, and increased endometrial proliferation rate, increased expression of proliferative genes, and increased pregnancy rates. The in vitro studies showed that PRP was associated with increased stromal and mesenchymal cell proliferation, increased expression of regenerative enzymes, and enhancement in cell migration. In infertile women undergoing assisted reproductive technology, one randomized clinical trial showed that PRP intrauterine infusion improved EMT, implantation rate, and clinical pregnancy rate (CPR) in patients with thin EMT, while 3 other trials involving subjects with RIF showed conflicting results related to CPR. Case series and cohort studies showed conflicting results pertaining to CPR. Data to date suggest that PRP may be beneficial in improving endometrial thickness and endometrial receptivity. However, further large prospective and high-quality trials are needed to assert its effect and to identify the population of patients that would benefit the most.

Concentrated small extracellular vesicles from menstrual blood-derived stromal cells improve intrauterine adhesion, a pre-clinical study in a rat model

We previously reported that transplantation of menstrual blood-derived stromal cells (MenSCs) significantly improved fertility restoration in intrauterine adhesion (IUA). However, it is difficult to obtain menstrual blood samples in some severe IUA patients who have amenorrhea or oligomenorrhea. Thus, a safe and effective stem cell replacement therapy is necessary to promote endometrial regeneration. Recent studies demonstrated that the effects of MenSCs are partly mediated in a paracrine manner via small extracellular vesicles (sEVs). To explore this possibility, we performed a pre-clinical study to investigate whether concentrated MenSC-derived sEVs (MenSCs-sEVs) are sufficient to repair IUA and the mechanisms underlying their action. Rat IUA models were established by mechanical injury, followed by the administration of MenSCs or MenSCs-sEVs through intrauterine transplantation. Consistent with the efficacy of MenSCs, MenSCs-sEVs effectively recovered the morphology, promoted regeneration of the glands and angiogenesis, and reversed endometrial fibrosis in the IUA uterus. The endometrial receptivity and pregnancy outcome significantly improved after repeated MenSCs-sEVs transplantations. In addition, all rats in the MenSCs-sEVs group had no hematological or biochemical abnormalities. Three-dimensional fluorescence imaging suggested that MenSCs tended to migrate through the bloodstream, whereas MenSCs-sEVs had a better localized therapeutic effect. Moreover, MenSCs and MenSCs-sEVs inhibited the TGFβ1/SMAD3 pathway in the IUA endometrium, while promoting the phosphorylation of SMAD1/5/8 and ERK 1/2 and upregulating the expression of BMP7. Thus, MenSCs-sEVs safely and effectively enhanced endometrial restoration, suggesting a promising non-cellular therapy for endometrial regeneration and a key role in MenSC-mediated IUA treatment.

Repair abilities of mouse autologous adipose-derived stem cells and ShakeGel™3D complex local injection with intrauterine adhesion by BMP7-Smad5 signaling pathway activation

BACKGROUND

The objective was to explore the therapeutic effect of autologous adipose-derived stem cells (ADSCs) combined with ShakeGel™3D transplantation to activate the BMP7-Smad5 signaling pathway to treat intrauterine adhesions (IUA).

METHODS

Autologous ADSCs were isolated and then merged with ShakeGel™3D. The IUA model was established by mechanical injury. The third generation of autologous ADSCs was injected directly into the uterus in combination with ShakeGel™3D. After 7 days of treatment, endometrial morphology, number of endometrial glands, endometrial fibrosis area, and fibrosis biomarker analysis by RT-PCR and IHC were examined. BMP7 and phosphorylation of Smad5 were also detected, and the recovery of infertility function in treated mice was evaluated.

RESULTS

Fluorescence-activated cell sorting (FACS) showed that autologous ADSCs expressed CD105 (99.1%), CD29 (99.6%), and CD73 (98.9%). Autologous ADSCs could still maintain a good growth state in ShakeGel™3D. Histological examination revealed that the number of endometrial glands increased significantly, and the area of fibrosis decreased. At the same time, the expression of BMP7 and Smad5 in the ADSCs + Gel group was significantly upregulated, and the final reproductive function of this group was partly recovered.

CONCLUSIONS

Autologous ADSCs can be used in combination with ShakeGel™3D to maintain functionality and create a viable three-dimensional growth environment. The combined transplantation of autologous ADSCs and ShakeGel™3D promotes the recovery of damaged endometrial tissue by increasing BMP7-Smad5 signal transduction, resulting in endometrium thickening, increased number of glands, and decreased fibrosis, leading to restoration of partial fertility.

Concentrated exosomes from menstrual blood-derived stromal cells improves ovarian activity in a rat model of premature ovarian insufficiency

Background

Premature ovarian insufficiency (POI) is one of the major causes of infertility. We previously demonstrated that transplantation of menstrual blood-derived stromal cells (MenSCs) effectively improved ovarian function in a murine model of POI. Recent studies indicated that mesenchymal stem cell-derived exosomes were important components in tissue repair. In this study, we investigated the therapeutic effects of MenSCs-derived exosomes (MenSCs-Exos) in a rat model of POI and its mechanism in restoring ovulation.

Methods

Ovaries of 4.5-day-old Sprague Dawley rats (SD rats) were cultured in vitro to evaluate the effects of MenSCs-Exos exposure on early follicle development. Furthermore, POI in rats was induced by intraperitoneal administration of 4-vinylcyclohexene diepoxide (VCD). Forty-eight POI rats were randomly assigned to four groups, each receiving a different treatment: PBS, MenSCs, MenSCs-Exos, and Exo-free culture supernatant of MenSCs. Estrous cyclicity, ovarian morphology, follicle dynamics, serum hormones, pregnancy outcomes, and molecular changes were investigated.

Results

Exposure to MenSCs-Exos promoted the proliferation of granulosa cells in primordial and primary follicles in vitro and increased the expression of early follicle markers Deleted In Azoospermia Like (DAZL) and Forkhead Box L2 (FOXL2) while inhibiting follicle apoptosis. In vivo, MenSCs-Exos transplantation effectively promoted follicle development in the rat model of POI and restored the estrous cyclicity and serum sex hormone levels, followed by improving the live birth outcome. In addition, transplantation of MenSCs-Exos regulated the composition of the ovarian extracellular matrix and accelerated the recruitment of dormant follicles in the ovarian cortex and increased proliferation of granulosa cells in these follicles.

Conclusion

MenSCs-Exos markedly promoted follicle development in vitro and in vivo and restored fertility in POI rats, suggesting a restorative effect on ovarian functions. The therapeutic effect of MenSCs-Exos transplantation was sustainable, consistent with that of MenSCs transplantation. Our results suggested that MenSCs-Exos transplantation may be a promising cell-free bioresource in the treatment of POI.