Collagen Scaffold Laden Mesenchymal Stem Cell Or Its Derivatives For Endometrial Regeneration

Human endometrium is a highly dynamic renewable tissue that undergoes 400 menstrual cycles and receives embryos by implantation throughout a woman's reproductive period.Endometrial traumas caused by recurrent curettage,caesarean section,myomectomy,or infection always result in intrauterine adhesions(IUAs)and infertility.Endometrial synechiotomy,hormone-therapy and intrauterine device placement are partly effective for the treatment of IUAs.However,the pregnancy outcome depends on the extent of the IUAs.Therefore,new approaches to reconstruct the endometrium to its normal morphology and function are crucial for severe casesUmbilical cord-derived mesenchymal stem cells(UC-MSCs),which have low immunogenicity,high proliferation rate,and are easy to collect,were reported to be effective for tissue regeneration.The main obstacle to treatment with MSCs is their low local persistence and utilization rate in the endometrium.A collagen scaffold(CS)can provide a suitable physical support and microenvironment for transplanted stem cells Collagen,a natural biomaterial and the main component of the extracellular matrix,has been widely utilized for tissue engineering scaffolds.In this thesis,the efficacies of the CS/UC-MSCs in restoring the structure,function and fertility restoration of the endometrium were assessed in a rat model of endometrial damage.However,the potential tumorigenicity,low infusion and low retention of MSCs are still controversial In contrast,MSC-derived exosomes exhibit a similar function to their source cells and have the advantages of higher biological stability,easier storage,immune-privileged status,and easier perfusion into tissues.Studies showed that MSC-derived exosomes can promote tissue regeneration.Therefore,a novel and viable cell-free therapeutic strategy by MSC-derived exosomes was proposed in the second research.We evaluated the effects of the association of nano-sized exosomes with a collagen scaffold(CS/Exos)on the regeneration of damaged endometrium and the restoration of fertility,as well as exploring the healing mechanism from the aspect of macrophage immunomodulation However,there are some problems restricting the wide application of exosomes,including complex extraction process,low production efficiency,short half-time,instability of biological effects because of different types and vitality of source stem cells.The dose-effect relationship of exosome-based therapy or stem-cell-based therapy is difficult to be standardized.In the process of tissue repair,a sufficient number of endogenous stem cells are recruited by many cytokins and chemokines and differentiate to repair injured tissue.These MSCs exhibits the advantages of immune-privileged status and high survival rate to overcome the shortages of stem-cell-based therapy Therefore,by emulating the process following tissue damage,we adopted a new stragety of promoting the recruitment and capture of sufficient numbers of mesenchymal stem cells.In the third research,we designed a combination CS with E7 peptide and stromal cell derived factor 1?(CS-E7/SDF-1?)to promote the recruitment and capture of endogenous mesenchymal stem cells.The effect of CS-E7/SDF-1? on endometrial repair and fertility restoration was evaluated in rat endometrium-damage model and intrauterine adhesion modelIn the first research,a CS loaded with human umbilical cord-derived mesenchymal stem cells(UC-MSCs)was fabricated and applied for endometrial regeneration.The CS/UC-MSCs promoted human endometrial stromal cell proliferation and inhibited apoptosis in vitro through paracrine effects.In a model of endometrial damage,transplantation with the CS/UC-MSCs maintained normal luminal structure,promoted endometrial regeneration and collagen remodeling,induced intrinsic endometrial cell proliferation and epithelium recovery,and enhanced the expression of estrogen receptor? and progesterone receptor.An improved ability of the regenerated endometrium to receive embryos was confirmed.Together,our results indicate that the CS/UC-MSCs promoted endometrial structural reconstruction and functional recoveryIn the second research,we designed MSC-derived exosomes laden scaffold(CS/Exos)for endometrium regeneration.The CS/Exos transplantation potently induced(?)endometrium regeneration,(?)collagen remodeling,(?)increased the expression of the estrogen receptor ?/progesterone receptor,and(?)restored fertility.Mechanistically,CS/Exos facilitated CD163+M2 macrophage polarization,reduced inflammation,and increased anti-inflammatory responsesin vivo and in vitro.By RNA-seq,miRNAs enriched in exosomes were the main mediator for exosomes-induced macrophage polarization.Overall,we demonstrated that CS/Exos treatment facilitated endometrium regeneration and fertility restoration by immunomodulatory functions of miRNAsIn the third research,the CS-E7/SDF-1? transplantation induced endometrium regeneration,collagen remodeling,increased the expression of the estrogen receptor?/progesterone receptor,and restored fertility in a rat endometrium-damaged model.In addition,The CS-E7/SDF-1? transplantation induced a similar effect in a rat intrauterine adhesion model.Mechanistically,CS-E7/SDF-1? induced the recruitment of bone marrow derived stem cells and increased anti-inflammatory responses in vivoOur research highlights the therapeutic prospects of CS/UC-MSCs,CS/Exos and CS-E7/SDF-1? for the management of IUAs and thin endometria,and these deserve further pharmaceutical development towards clinical use.