Effects of hypoxia-preconditioned HucMSCs on neovascularization and follicle survival in frozen/thawed human ovarian cortex transplanted to immunodeficient mice

Abstract

Background The massive loss of follicles in the early stage of ovarian tissue transplantation is considered a significant restriction to the efficacy of ovarian tissue cryopreservation (OTC) and transplantation (OT). The use of mesenchymal stem cells (MSCs) before transplantation of ovarian fragments shortened the hypoxic period and boosted neovascularization. Hypoxia-preconditioned MSCs can enhance the potential of angiogenesis. Can hypoxia-preconditioned human umbilical cord mesenchymal stem cell (HucMSCs) and ovarian tissue co-xenotransplantation improve more neovascularization and subsequently more follicle survival in human ovarian tissue? Methods Frozen-thawed cortical pieces from 4 patients were transplanted into the bilateral renal capsule of immune-deficient nude mice without HucMSCs or normoxia/hypoxia-preconditioned HucMSCs. Sixty-four mice were randomly distributed into 4 groups. In each group, the mice were euthanized for blood and/or graft retrieval on post-transplantation days 3 (n = 8) and 7 (n = 8), respectively. Non-grafted frozen-thawed ovarian fragment was taken for non-grafted control. Grafts were histologically processed and analysed for follicle density and atretic follicles by HE, neovascularization by CD34 and CD31 immunohistochemical staining, primordial follicle growth by Ki67 staining, and apoptosis of stromal cell and follicles by immunofluorescence using TUNEL. The ROS and TAC levels of grafted and non-grafted tissue were assessed. We evaluated the protein expression of HIF1α, VEGFA, pAkt, Akt, and GDF9 in grafted and non-grafted ovarian tissue. E2, Prog, AMH, and FSH levels in the plasma of mice were measured after 3 and 7 days of OT. Results Hypoxia-preconditioned HucMSCs positively protect the grafted ovarian tissue by significantly decreasing the apoptosis and increasing higher expression of CD31, CD34, and VEGFA for earlier angiogenesis. They are crucial to preserving the resting primordial follicle pool by modulation of follicle death. Conclusion This is the first study to demonstrate that co-transplantation of hypoxia-preconditioned HucMSC with ovarian tissue improved earlier vascularization of ovarian grafts in the early post-grafting period, which correlates with increased follicle survival and reduced apoptosis. The HIF1α/VEGFA signal pathways may play an important role in elucidating the mechanisms of action of hypoxia-preconditioned HucMSCs with regard to OT and clinical implementation.

MSCs play a vital function in Tibial cortex transverse transport surgery

“…CD31 plays a crucial role in in ammation, immune response and angiogenesis, and is involved in endothelial cell migration, cell connection development and homeostasis, and capillary formation [27,28]. MSCs can actively protect transplanted tissues by increasing higher expression of CD31, CD34, and VEGFA for early angiogenesis [29].Our results suggest that MSCs in TTT accelerate wound healing by promoting the expression of CD31 in neovascularization and new skin.…”

Human ovarian tissue xenotransplantation in 3D-printed tissue trapper basket integrated with human umbilical cord mesenchymal stem cells

“…The hypoxic HUC-MSCs exhibited notable protection against apoptosis within the graft tissues. Additionally, they stimulated the upregulation of CD31, CD34, and VEGF genes, facilitating efficient and prompt angiogenesis (32).They also protect and preserve ovarian follicles by inducing changes in follicular death. Previous research on the effects of umbilical cord MSCs that were grafted with OT, 48 hours before grafting under hypoxic conditions showed anti-apoptotic, angiogenic, and protective effects on ovarian reserves (32) Based on the findings mentioned earlier, our research revealed that despite nonhypoxic cell culture conditions, the HUC-MSCs exhibited comparable anti-apoptotic, angiogenic, and protective effects.…”

Enhancement of Vascularization and Ovarian Follicle Survival Using Stem Cells in Cryopreserved Ovarian Tissue Transplantation—A Systematic Review

“…After being cryopreserved by a slow-freezing procedure and subsequently thawed, ovarian tissue fragments were transplanted to SCID or BALB/c mice. Grafting sites differed between studies, ranging from orthotopic intraperitoneal transplantation to heterotopic graft positioning under the renal capsule, subcutaneously, or into the back muscle region [20][21][22][23]. Two studies used commercially acquired human ASCs and performed a two-step procedure.…”

“…They preconditioned their human umbilical cord mesenchymal stem cells (hUC-MSCs), predicting that a hypoxic environment will enhance proangiogenic factor secretion. The hUC-MSCs were placed in a hypoxic incubator with only 3% O 2 for 48 h before transplantation [20].…”