Since stem cells are “primitive cells” that are not fully differentiated in the human body, they can differentiate and “regenerate” various tissues and organs. If stem cells can be used to differentiate into specific types of cells, they can replace diseased cells that have lost their functions, or generate human organs such as heart, liver and kidney in the laboratory, which can solve the shortage of transplanted organs and bring hope for curing cancer, diabetes, Parkinson’s syndrome, cardiovascular diseases, ischemic diseases of the lower limbs and other intractable diseases.
In early 2008, scientists in the United States injected stem cells from rat embryos into the stromal scaffold of a dead rat’s heart, causing the dead heart to start contracting after four days and resume beating after eight days, successfully producing the world’s first living heart that could grow on its own in vitro. The world-renowned British medical journal The Lancet reported that in June 2008, scientists from three European countries teamed up to perform the world’s first custom organ transplant, transplanting a 30-year-old Spanish woman with a damaged trachea with a trachea grown from autologous stem cells.
The scientists first removed part of the trachea from a 51-year-old donor who died of a cerebral hemorrhage, decellularized it, leaving only the basic scaffold of extracellular matrix, then extracted bone marrow stem cells from the patient, cultured them as cartilage cells for the tracheal wall, and let them grow into a trachea on the collagen scaffold. Five months after the surgery, the 30-year-old patient has fully recovered. With this decellularization process, scientists hope to open the door to artificially tailored organs to grow any organ such as kidney, liver, lung, heart and pancreas. Medical experts predict that it will only take about 20 years for the stem cell-grown organ transplant technique to develop into a routine procedure. At that time, human beings will no longer have to wait for the absence of transplant organs.
Stem cell transplants could also benefit patients with damaged corneas, and in 2010, the New England Journal of Medicine, the world’s top clinical journal, reported that Italian scientists had removed a small number of healthy stem cells from a patient’s eye and cultured them, then reimplanted the cultured stem cells into the patient’s eye. These transplanted stem cells will repair the original damaged corneal tissue.
Because these stem cells come from the patient’s own body, they do not cause rejection. Dozens of patients whose eyes were severely damaged in chemical accidents have successfully regained their vision through autologous stem cell transplants. French researchers placed human embryonic stem cells on an artificial net that helps the cells form skin layers and then implanted them into rats, where the stem cells grew into structurally developed human skin after 12 weeks. This method of growing new skin would greatly benefit severe burns that rely on skin implants to heal. Recently, it was reported in the media that there are plans to try to use the advanced technology of stem cell artificial skin reengineering to recreate “skin” for severe burn victims of the Ichun air disaster in the coming period.
Our scientists have also conducted research on clinical treatment with adult stem cells. The types of stem cell clinical applications include lower limb ischemic diseases, cardiac system diseases such as myocardial infarction, neurological system diseases such as Parkinson’s disease and stroke sequelae, and bone diseases such as femoral head necrosis.
Among them, the Hematology Hospital of the Institute of Hematology, Peking Union Medical College, Chinese Academy of Medical Sciences has been the first to carry out peripheral blood stem cell transplantation for arterial ischemic diseases in China, and has treated nearly 100 cases with an efficiency rate of over 90%, reaching the international leading level. Although the prospect of stem cell transplantation is attractive, at present, except for hematopoietic stem cell transplantation for hematological diseases, it is mostly in experimental research stage in many fields.