| Hematopoietic stem cell therapy,which has been proven to be able to cure many blood disease such as Leukemia,hemophilia or blood cancer,is the maturest stem cell transplantation medical technology.The stem cells used in clinic mainly come from the Peripheral blood,marrow of adults and the umbilical cord of the burned infants,however,there are many reasons that limit the clinical use of hematopoietic stem cells from these sources.Therefore,searching for more sources of hematopoietic stem cells has become an urgent problem in the clinical use of those stem cells.Recently,the research shows there are abundant stem cells in the placenta,of which the character is the same as the stem cells within umbilical cord blood,can be the new source of stem cells in clinical application.This research is going to separate karyote and CD34~+stem cells from placenta by applying enzymatic treatment and perfusion.The cells will be frozen and stored as a placenta hematopoietic stem cell bank,or be used immediately after isolation.The outcomes are as follows:1.The average number of karyote is(16.82±6.08)×10~8 collected by perfusion.By using enzymatic treatment additionally,the average number of karyote is up to(7.79±3.13)×10~8,which is 32%of the average total of karyote isolated by this trial.The result means that karyotes can not be isolated by perfusion effectively.Thus it is necessary for combining with enzyme treatment in order to isolate the remaining karyote within placenta.2.The article published by Shan dong umbilical cord bank in 2001 shows that the average of karyotes and CD34~+hematopoietic stem cells collected from placenta is(24.65±6.50)×10~8 and(22.60±7.29)×10~6,respectively,which was at least 2 times the average number of karyotes and CD34~+hematopoietic stem cells collected in cord blood.When hematopoietic stem cells isolated from the placenta are cultured in vitro,the placenta-derived hematopoietic stem cells have good colony forming ability in vitro culture,that is,they have good hematopoietic differentiation and proliferation ability.The results showed that placental hematopoietic stem cells and umbilical cord blood hematopoietic stem cells are in line with the requirements of clinical use,and fully meet the requirements of building a hematopoietic stem cell bank,providing experimental basis for the establishment of placental hematopoietic stem cell bank.3.When cell viability assays and cell proliferation assays are performed on 18 placental nucleated cells recovered from placental hematopoietic stem cell pools to be constructed after long-term cryopreservation,we find that the activity of cryopreserved placental nucleated cells after resuscitation was maintained at more than 80%,which is in line with the current requirements of the cord blood bank for cell viability after cryopreservation.The resuscitated placental karyotes can proliferate in a culture system conducive to the growth of nucleated cells,indicating that the resuscitated nucleated cells did not undergo changes in biological characteristics.Therefore,the protocol,whose purpose is to construct a placental hematopoietic stem cell bank for long-term preservation of placental nucleated cells,is planned to establish in this study proves to be feasible and reliable.In summary,this experiment shows that the placenta is rich in hematopoietic stem cells.The hematopoietic stem cells isolated from the placenta can be used as a reliable new source of umbilical cord blood hematopoietic stem cells,and can better solve the clinical application of hematopoietic stem cells in cord blood Insufficient problem.Establishing a placental hematopoietic stem cell bank similar to cord blood bank is of great importance.Finally,this study looks forward to the requirements for the establishment of the placental hematopoietic stem cell bank and its operation. |
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