Therapeutic Effects of VEGF Gene-Transfected BMSCs Transplantation on Thin Endometrium in the Rat Model

The application of tissue engineering strategies for uterine regeneration

Uterine injuries, particularly damages to endometrium, are usually associated with abnormal menstruation, recurrent miscarriage, pregnancy complications, and infertility. Tissue engineering using cell-based, biomolecule-based, or biomaterial and scaffold-based strategies has emerged as a novel and promising approach for uterine regeneration. Stem cells, biomolecules, and porous scaffolds used alone or, very often, used in combination as a more effective treatment means have shown great potential in promoting uterine regeneration. The reported preclinical studies have indicated that appropriate tissue engineering strategies could safely and effectively reconstruct not only endometrium but also partial or even the whole uterine structure. However, the progress in the uterine regeneration area is slow in comparison to that of regenerating many other body tissues and hence it still remains a great challenge to apply uterine tissue engineering for clinical applications. In this review, conventional treatments for uterine-related diseases are briefly reviewed and discussed first. Subsequently, tissue engineering strategies (cell-based, biomolecule-based, biomaterial and scaffold-based, or their combinations) for uterine repair in preclinical studies and clinical trials are presented and analyzed. Finally, the challenges and perspectives in uterine regeneration are pointed and discussed. Despite various limitations and obstacles, the tissue engineering approach is viable and holds high promise for uterine regeneration.

Evaluation of the effect of an amniotic membrane derived bio-nano product (LifeCell) on human endometrial cells proliferation and gene expression: An in-vitro study

OBJECTIVE

Successful assisted reproductive technology (ART) requires a receptive endometrium with appropriate thickness and the presence of specific cytokines, chemokines, and growth factors. Despite advancements in ART, the success rates remain suboptimal, particularly in individuals with thin endometrium resistant to treatment. In this study, we evaluated the potential effects of LifeCell, a product of BioNano Technology, on the growth, development, and acceptance of endometrial cells.

STUDY DESIGN

We cultured endometrial cells in a defined medium with different concentrations of LifeCell and examined cell growth, development, and the expression of genes involved in endometrial receptivity.

RESULTS

Co-culture of primary human endometrial cells with 5 % Life cell solution significantly stimulated the endometrial cell growth, development and receptivity genes expression. The expression levels of FGF2 and CSF in the 72 h co-cultured were significantly increased compared with other groups (P < 0.01). HOXA10 and LIF significantly increased in the 72 h co-cultured compared with 24 h co-cultured and control groups but had no significant level compared with 48 h cocultured. HOXA10 significantly increased in the 48 h cocultured compared with control group. IL-6 and Hb-EGF increased in the 48 h co-cultured compared to other groups but had no significant level. VEGF increased in the treated groups compared to control but had no significant level. The expression of OPN, unlike the other genes, decreased in the treated group compared to the control, which was not significant.

CONCLUSIONS

These findings suggest that LifeCell may be a potential option for patients with treatment-resistant thin endometrium in cases of infertility.

Angiogenic lipid-based drug delivery system (PhytoSolve) for treatment of a thin endometrium in animal model

Impaired vascular growth resulting from reduced vascular endothelial growth factor (VEGF) in the epithelial tissue of the glands is a primary cause of thin endometrium. Inducing angiogenesis offers a possible therapeutic strategy for this condition. This study aimed to develop a novel drug delivery system using S75 lipoid loaded with VEGF for thin endometrium therapy. The formulation of PhytoSolve consisted of a combination of lipid S75, glycerol, and MCT oil, which was prepared utilizing a probe sonicator. Female NMRI mice (n=30) were divided into six groups: control, sham, thin endometrial model, VEGF treatment, PhytoSolve treatment, and VEGF/PhytoSolve treatment. A thin endometrial model was induced by injecting 95 % ethanol. After the treatment period, tissue samples were collected to assess the endometrial thickness-the mean particle size of the PhytoSolve formulation measured 67.57±7.07 nm. Approximately 40 % of the loaded VEGF was released within the first 24 hours, followed by a sustained release rate of 10-20 % daily. The PhytoSolve group containing VEGF exhibited significantly increased endometrial thickness compared to the VEGF group (P<0.05). S75 lipoid-based PhytoSolve loaded with VEGF effectively promoted blood vessel formation. The combination of PhytoSolve S75 and VEGF holds promise for developing a biocompatible drug delivery system with therapeutic potential for treating thin endometrium and various other biomedical applications.

Combination Therapy of Bone Marrow Mesenchymal Stem Cell Transplantation and Electroacupuncture for the Repair of Intrauterine Adhesions in Rats: Mechanisms and Functional Recovery

Transplantation of bone marrow mesenchymal stem cells (BMSCs) has demonstrated promising clinical utility in the treatment of endometrial injury and the restoration of fertility. However, since the efficacy of BMSCs after transplantation is not stable, it is very important to find effective ways to enhance the utilisation of BMSCs. Electroacupuncture (EA) has some positive effects on the chemotaxis of stem cells and diseases related to uterine injury. In this study, we established the intrauterine adhesion (IUA) model of the Sprague-Dawley rat using lipopolysaccharide infection and mechanical scratching. Phosphate-buffered saline, BMSCs alone, and BMSCs combined with EA were randomly administered to the rats. Fluorescent cell labelling showed the migration of transplanted BMSCs. H&E staining, Masson staining, Western blot, immunohistochemistry, ELISA, and qRT-PCR were utilised to detect changes in endometrial morphology and expressions of endometrial receptivity-related factors, endometrial pro-inflammatory factors, and fibrosis factors. Finally, we conducted a fertility test to measure the recovery of uterine function. The results showed that EA promoted transplanted BMSCs to migrate into the injured uterus by activating the SDF-1/CXCR4 axis. Endometrial morphology showed the most significant improvement in the BMSC + EA group. The expressions of endometrial pro-inflammatory factors and fibrosis indexes in the BMSC + EA group were lower than those in the model and BMSC groups. Further studies revealed that the expression of endometrial receptivity-related factors and the number of embryos implanted on day 8 of gestation increased in the BMSC + EA group compared with the model group and the BMSC group.

Transplantation of bFGF-transfected bone mesenchymal stem cells on collagen scaffolds promotes the regeneration of injured rat endometrium

OBJECTIVE

This study aimed to verify the role of basic fibroblast growth factor (bFGF)-bone mesenchymal stem cells (BMSCs) loaded on collagen scaffolds for the repair of injured endometrium.

METHODS

We established an intrauterine adhesion (IUA) model in rats by endometrial resection and implanted BMSCs and bFGF-BMSCs loaded on collagen scaffolds into uteri. A total of 100 IUA model rats were divided into five groups: the control group, scaffold group, BMSC+scaffold group, vector-BMSC group, and bFGF-BMSC+scaffold group. The rats were sacrificed on the 3^rd, 7^th, 15^th, and 45^th days. The endometrium thickness, number of glands, and microvascular density were measured by hematoxylin and eosin staining, Masson staining, and immunohistochemistry staining of CD31. The expression of bFGF, vascular endothelial growth factor (VEGF), vimentin, and Ki67 was assayed by immunohistochemistry staining.

RESULTS

The bFGF-BMSCs loaded on the collagen scaffold significantly increased the endometrial thickness, gland number, and microvascular density, which greatly promoted the regeneration of the injured endometrium (P<0.0001). In addition, the expression levels of bFGF, VEGF, vimentin, and Ki67 were significantly higher in the bFGF-BMSC+scaffold group than in the BMSC+scaffold group (P<0.05).

CONCLUSIONS

Our findings indicated that bFGF-BMSCs loaded on collagen scaffolds have the ability to prompt the regeneration of the endometrium after injury, contributing to a better understanding of stem cell treatment for intrauterine adhesion.

Human Umbilical Cord Mesenchymal Stem Cells Encapsulated with Pluronic F-127 Enhance the Regeneration and Angiogenesis of Thin Endometrium in Rat via Local IL-1β Stimulation

Thin endometrium (< 7 mm) could cause low clinical pregnancy, reduced live birth, increased spontaneous abortion, and decreased birth weight. However, the treatments for thin endometrium have not been well developed. In this study, we aim to determine the role of Pluronic F-127 (PF-127) encapsulation of human umbilical cord mesenchymal stem cells (hUC-MSCs) in the regeneration of thin endometrium and its underlying mechanism. Thin endometrium rat model was created by infusion of 95% ethanol. Thin endometrium modeled rat uterus were treated with saline, hUC-MSCs, PF-127, or hUC-MSCs plus PF-127 separately. Regenerated rat uterus was measured for gene expression levels of angiogenesis factors and histological morphology. Angiogenesis capacity of interleukin-1 beta (IL-1β)-primed hUC-MSCs was monitored via quantitative polymerase chain reaction (q-PCR), Luminex assay, and tube formation assay. Decreased endometrium thickness and gland number and increased inflammatory factor IL-1β were achieved in the thin endometrium rat model. Embedding of hUC-MSCs with PF-127 could prolong the hUC-MSCs retaining, which could further enhance endometrium thickness and gland number in the thin endometrium rat model via increasing angiogenesis capacity. Conditional medium derived from IL-1β-primed hUC-MSCs increased the concentration of angiogenesis factors (basic fibroblast growth factor (bFGF), vascular endothelial growth factors (VEGF), and hepatocyte growth factor (HGF)). Improvement in the thickness, number of glands, and newly generated blood vessels could be achieved by uterus endometrium treatment with PF-127 and hUC-MSCs transplantation. Local IL-1β stimulation-primed hUC-MSCs promoted the release of angiogenesis factors and may play a vital role on thin endometrium regeneration.

Intrauterine Injection of Umbilical Cord Mesenchymal Stem Cell Exosome Gel Significantly Improves the Pregnancy Rate in Thin Endometrium Rats

Human umbilical cord mesenchymal stem cell (HUMSC)-exosome gel played a significant role in promoting thin endometrial receptivity and improving the pregnancy rate by inhibiting endometrial fibrosis and accelerating subendometrial microangiogenesis. High-quality HUMSC-exosome were obtained by pretreating HUMSC with transforming growth factor-β₁ (TGF-β₁). Exosome gel mixture has good biocompatibility and physical rheological properties, stabilizing the structure of exosomes and prolonging the action of exosomes in the uterine cavity. HUMSC or HUMSC-derived exosomes were used to treat rat model of thin endometrium. In animal experiments, four groups, including the HUMSC, HUMSC-exosome, model (negative control), and sham operation groups, were designed. The therapeutic effects were evaluated by the thickness of the endometrium, the number of glands, the subendometrial vessel density, the markers of endometrial receptivity, and the pregnancy rate. In an in vivo study, three groups, involving HUMSC-coculture, HUMSC-exosome, and the control, were explored. The proliferation and migration of the human endometrial stromal cells (HESCs) were further determined by cell scratch and 5-ethynyl-2'-deoxyuridine (EdU) assays. The protein expression of the TGF-β₁/smad2/3 signaling pathway was determined by Western blot. After treatment, the thickness of the endometrium, the number of glands, and the subendometrial microangiogenesis were obviously increased, and the level of inhibition of endometrial fibrosis, molecular markers of endometrial receptivity, and the pregnancy rate were also significantly improved. HUMSC-exosome and HUMSC significantly promoted the migration and proliferation of HESCs. And it was confirmed that HUMSC-exosome were superior to HUMSC in inhibiting HESCs fibrosis through TGF-β₁/smad2/3 signaling pathway at the protein expression level.

The potential of Zishen Yutai pills to facilitate endometrial recovery and restore fertility after induced abortion in rats

CONTEXT

Abortions damage the endometrium in women. Currently, therapeutic options for endometrial recovery are limited. Zishen Yutai Pill (ZYP) was found to promote endometrial blood supply as a traditional Chinese medicine. However, whether ZYP promotes endometrial recovery post-abortion has not yet been explored.

OBJECTIVE

This study evaluated the role of ZYP in rat endometrial recovery after induced abortion and explored its mechanism of action.

MATERIALS AND METHODS

Sprague-Dawley rats were divided into three groups: no-operation group, control group, and ZYP group. The rats in the control and ZYP group were induced abortion, and then treated with normal saline or ZYPs, respectively, for 1-3 oestrous cycles. Morphological changes in the endometrium were examined. Expression levels of the factors related to endometrial recovery were analyzed. The duration of this study was almost seven months.

RESULTS

The endometrial thickness (7.3 ± 0.17 mm) and number of glands (5.5 ± 0.20) increased significantly in the ZYP group compared with those in the control group (5.5 ± 0.15 mm and 3.5 ± 0.18; p < 0.05). Fibrosis of the endometrium was ameliorated by ZYP administration (45 ± 6% vs. 58 ± 7%; p < 0.05). ZYPs treatment increased the expression of VEGF, ER, MMP-9, LIF, and HB-EGF, but decreased TGF-β expression. Moreover, the average number of pups in the ZYP group (9.0 ± 1.5) was greater than that in the control (4 ± 1.3).

DISCUSSION AND CONCLUSION

ZYPs accelerate endometrial recovery and restored fertility in rats, suggesting its potential to promote human endometrial repair.

Angiogenic Microspheres for the Treatment of a Thin Endometrium

The poor vascular development of an endometrium is the key cause of a thin endometrium due to the vascular endothelial growth factor (VEGF) decreasing in the glandular epithelium. Hence, inducing angiogenesis is an effective strategy for thin endometrium treatment in clinic. Herein, we developed a novel angiogenic hydrogel microsphere based on methacrylated hyaluronic acid (HAMA) loaded with VEGF for the treatment of a thin endometrium by a microfluidic electrospray technique. The generated HAMA microspheres with uniform size, porous structure, and satisfactory biocompatibility increased the drug-loading ability and controlled the drug-release rate by adjusting the hydrogel concentration. Besides, the HAMA microspheres loaded with VEGF showed satisfactory biocompatibility and promoted blood vessel formation in vitro. More importantly, the combination of HA and VEGF promoted new blood vessels and endometrial regeneration of a thin endometrium in vivo. Therefore, the combination of HA and VEGF would be conducive to the development of a drug-delivery microsphere with excellent biocompatibility and therapeutic effect for thin endometrium treatment and other biomedical applications.

Strategies for managing asherman's syndrome and endometrial atrophy: Since the classical experimental models to the new bioengineering approach

Endometrial function is essential for embryo implantation and pregnancy, but managing endometrial thickness that is too thin to support pregnancy or an endometrium of compromised functionality due to intrauterine adhesions is an ongoing challenge in reproductive medicine. Here, we review current and emerging therapeutic and experimental options for endometrial regeneration with a focus on animal models used to study solutions for Asherman's syndrome and endometrial atrophy, which both involve a damaged endometrium. A review of existing literature was performed that confirmed the lack of consensus on endometrial therapeutic options, though promising new alternatives have emerged in recent years (platelet-rich plasma, exosomes derived from stem cells, bioengineering-based techniques, endometrial organoids, among others). In the future, basic research using established experimental models of endometrial pathologies (combined with new high-tech solutions) and human clinical trials with large population sizes are needed to evaluate these emerging and new endometrial therapies.

Encapsulated VEGF121-PLA microparticles promote angiogenesis in human endometrium stromal cells

Background

In this study, Vascular Endothelial Growth Factor 121 expressed abundantly in endometrial stromal cells is encapsulated with poly-l-lactide and characterized the properties for endometrial angiogenesis. We studied the migration, proliferation and the protein levels of human immortalized endometrium stromal cells after treating the cells with recombinant Vascular Endothelial Growth Factor (200 and 500 nanogram), and poly-l-lactide loaded Vascular Endothelial Growth Factor 121 (day 1, 20 and 30). The present study explains endometrium angiogenesis because endometrium plays an important role in pregnancy.

Results

Migration and proliferation studies in endometrium cells proved the efficiency of Vascular Endothelial Growth Factor and poly-l-lactide loaded Vascular Endothelial Growth Factor 121. This proliferated and increased the migration of the cells in vitro and also activated the Protein kinase B, Phosphatidylinositol-4, 5-Bisphosphate 3-Kinase Catalytic Subunit Beta, α-Smooth muscle actin and vascular endothelial growth factor receptor 2 pathways. Western blot analysis showed the increased expression levels of kinases, smooth muscle actin and vascular endothelial growth factor receptor 2 after the treatment with Vascular Endothelial Growth Factor and poly-l-lactide loaded Vascular Endothelial Growth Factor 121 particles in comparison to the control group. The elevated levels of α-Smooth muscle actin in endometrium cells with Vascular Endothelial Growth Factor prove the regulation of angiogenesis in vitro.

Conclusion

Endometrium thickness is one of the important factors during implantation of embryo and pregnancy. Slow release of VEGF from PLA encapsulated microparticle further controls the endothelial cell proliferation and migration and helps in the promotion of angiogenesis. The combined effect studied in vitro could be used as a pro-angiogenic drug on further in vivo confirmation.

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.

Local SDF-1α application enhances the therapeutic efficacy of BMSCs transplantation in osteoporotic bone healing

Bone defect healing is markedly impaired in osteoporotic patient due to poor bone regeneration ability. Stromal cell derived factor-1α (SDF-1α) plays a pivotal role in the repair of various injured tissues including bone. Here, we definite that SDF-1α hydrogels potentiates in vivo osteogenesis of bone marrow-derived stromal stem cells (BMSCs) in osteoporosis. The characteristics of rat primary BMSCs including superficial markers by flow cytometry and multi-lineage differentiation by induction were determined. At different time intervals, the release media from the SDF-1α-releasing hydrogels were collected to identificate SDF-1α exhibited a sustained release profile and maintained its bioactivity after release from the hydrogels to stimulate chemotaxis of BMSCs in a time dependent manner. Bilateral alveolar defects were operated in ovariectomized (OVX) rats and repaired with systemic BMSCs transplantation with or without the hydrogels. Local administration of SDF-1α significantly enhanced BMSCs recruitment and promoted more bone regeneration as well as the expression of OCN and Runx2 compared with the effect of BMSCs transplantation alone. Moreover, after BMSCs transplantation with SDF-1α delivery, macrophage polarization was promoted toward the M2 phenotype, that is identified as an important symbol in tissue regeneration process. Taken together, local SDF-1α application enhances the efficacy of BMSCs transplantation therapy in osteoporotic bone healing, suggesting clinical potential of SDF-1α to serve as a therapeutic drug target for osteoporosis treatment.

The synergistic effect of electroacupuncture and bone mesenchymal stem cell transplantation on repairing thin endometrial injury in rats

BACKGROUND

Tissue regeneration disorder after endometrial injury is an important cause of intrauterine adhesions, amenorrhea, and infertility in women. Both bone marrow mesenchymal stem cell (BMSC) transplantation and electroacupuncture (EA) are promising therapeutic applications for endometrial injury. This study examined their combined effects on thin endometrium in rats and the possible mechanisms underlying these effects.

METHODS

A thin endometrial model was established in Sprague-Dawley (SD) rats by perfusing 95% ethanol into the right side of the uterus. The wounds were randomly treated with PBS (model group), BMSCs only (BMSC group), EA only (EA group), and BMSCs combined with EA (BMSC + EA group). Endometrial morphological alterations were observed by hematoxylin and eosin (H&E) staining. Changes in markers of epithelial and stromal endometrium cells, endometrial receptivity-related chemokines, and paracrine factors were detected using immunohistochemistry, western blotting, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Finally, the functional recovery of the uterus was evaluated by determining the rate of embryo implantation.

RESULTS

As shown by endometrial morphology, the damaged uteri in all the treatment groups recovered to some extent, with the best effects observed in the BMSC + EA group. Further studies showed that EA promoted the migration of transplanted BMSCs to damaged uteri by activating the stromal cell-derived factor-1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4) axis. As compared with the other groups, upregulated expression of endometrial cytokeratin and vimentin, increased secretion of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in endometrial lesions, and improved embryo implantation rates on the 8th day of pregnancy were found in the BMSC + EA group.

CONCLUSIONS

EA plays an important role in supporting BMSCs in the repair of thin endometrium, most likely by promoting the migration of BMSCs and enhancing the paracrine effect of BMSCs.