[science popularization] a perfect summary of “the development of stem cell therapy”

Clinical research in the field of stem cells is steadily advancing at a rapid pace, which is the general trend. A series of national policies also provide strong support and guarantee for the development of stem cell technology. Tonight, let’s talk about the development of stem cell therapy. In brief, stem cells are a kind of primitive undifferentiated cells with multi-directional differentiation potential and self replication ability, and are the primitive cells forming various tissues and organs in the body. For example, mesenchymal stem cells, tissue stem cells, umbilical cord blood stem cells and pluripotent stem cells, which have different therapeutic potential, are the favorite in the field of regenerative medicine. Stem cell therapy refers to the use of stem cells or stem cell derived cells, transplanted into the body with special technology to replace or repair the damaged cells, tissues or organs of patients. Here, the first generation of stem cell therapy refers to: natural stem cells isolated from human body have been used in clinical treatment for decades, mainly involving the transplantation of hematopoietic stem cells and various tissue-derived mesenchymal stem cells. The second generation of stem cells refers to the application of differentiation products of pluripotent stem cells for cell therapy. There is also the next generation of stem cell therapy: genetically engineered stem cell therapy, which we will not introduce for the time being. The first generation of stem cells used in clinic are mainly adult stem cells, such as hematopoietic stem cells, mesenchymal stem cells from various sources, tissue stem cells, fetal stem cells, etc. < p > < p > bone marrow transplantation has been used in the treatment of malignant blood diseases as early as more than 60 years ago. Hematopoietic stem cells are adult stem cells that we know most about. They are also real stem cells, which can replicate and differentiate. It is mainly used to replenish hematopoietic stem cells after radiotherapy / chemotherapy, and then remodel the whole hematopoietic system and immune system. < p > < p > hematopoietic stem cells are the most commonly used stem cell types in clinical application. Around the world, about 50000 bone marrow transplant patients receive hematopoietic stem cell transplantation every year. In addition to bone marrow, cord blood is also an important source of hematopoietic stem cells. In addition to hematopoietic stem cells, mesenchymal stem cells have gone the furthest in clinical transformation. Mesenchymal stem cell therapy also belongs to the first generation of stem cell therapy. MSCs usually come from bone marrow, adipose tissue, umbilical cord, placenta and dental pulp. MSCs are easy to isolate and amplify, and have many biological functions, such as immune regulation, anti apoptosis, angiogenesis, anti scar and nutritional support. < p > < p > in 1995, the first case of MSCs therapy was put into clinical application [2], and it has been more than 20 years. At present, in the ClinicalTrials.gov There are nearly 1000 clinical studies on MSCs, involving hundreds of diseases, including nervous system, cardiovascular system and orthopedic diseases. < / P > < p > it should be noted that clinical research does not mean that the technology is mature. Only when the stem cell products are approved for marketing and become stem cell drugs, can stem cells be regarded as “real” stem cell drugs that patients can rest assured to use. < / P > < p > in 2012, Canada approved Prochymal developed by Osiris for the treatment of graft-versus-host disease [3]; < / P > < p > up to now, the US FDA has not approved any MSCs based therapies for marketing. The ryoncil product of mesoblast is expected to become the stem cell therapy approved by 2020 and the first MSCs product approved by FDA in the United States. The first clinical application report of fetal stem cells in the world was reported in 1988 when the substantia nigra and adrenal medulla of fetus were transplanted into the brain of patients with Parkinson’s disease for treatment [5]. Fetal tissue-derived stem cells have strong regeneration ability. Transplantation of fetal brain cells can replace degenerative neurons. < / P > < p > although this therapy has a certain effect, it is very difficult to obtain the cells and there are serious ethical problems. The number of stem cells isolated from each donor fetus is limited, and it is easy to lose the stem cells in vitro. < p > < p > it was first reported that human embryonic stem cells were successfully cultured in 1998 [6], and human induced pluripotent stem cells were successfully reported in 2007 [7]. In theory, pluripotent stem cells can form any kind of cells in vivo. Pluripotent stem cells have been in clinical trials for less than 10 years, and various treatments have been tried. In 2009, FDA approved the clinical trial of embryonic stem cells to treat spinal cord injury. In 2010, FDA approved the clinical trial of embryonic stem cells to treat macular degeneration. In 2014, FDA approved the clinical trial of embryonic stem cells to treat type I diabetes. < / P > < p > many clinical trials based on embryonic stem cells have been launched in China, such as Parkinson’s disease, macular degeneration, meniscus injury, and reproductive system diseases. Many clinical trials based on IPSC have been carried out in Japan, such as retinal macular degeneration, Parkinson’s disease, heart failure, spinal cord injury and other diseases. I will not repeat them here. In addition to repairing tissue function, immunotherapy based on pluripotent stem cells is becoming a hot topic.. FDA has approved the first ind application for IPSC derived car-t cell therapy for recurrent / refractory B-cell malignancies. < / P > < p > numerous clinical evidences show that the treatment based on pluripotent stem cells is safe and well tolerated by patients. Despite many advances, pluripotent stem cell therapy also faces a series of challenges. < p > < p > the pluripotent stem cell products may form tumors or ectopic tissues in vivo, especially when residual pluripotent stem cells or highly proliferating progenitor cells exist in the final product transplanted into patients, the risk is even higher. There is potential genetic instability in the pluripotent stem cells themselves, and chromosome abnormalities or gene mutations may occur during long-term in vitro culture or differentiation. < p > < p > stem cell therapy is one of the most advanced and popular directions in medical research, and has achieved exciting results. From the first case of stem cell transplantation to the present, the field of stem cells has changed dramatically. Important discoveries and milestones of the first generation stem cell therapy: in 1959, the bone marrow transplantation of the first identical twins marked the beginning of the era of stem cell transplantation; in 1988, the first fetal tissue cell transplantation was used to treat Parkinson’s disease; in 1995, mesenchymal stem cells were used for the first time in human clinical practice. Important discovery and milestone of the second generation stem cell therapy: in 1998, human embryonic stem cells were cultured for the first time; in 2007, human induced pluripotent stem cells were reported for the first time. In 2012, we first reported the safety and biological function of pluripotent stem cell therapy in the treatment of macular degeneration. < / P > < p > whether it is the first generation of adult stem cell based therapy or the second generation of pluripotent stem cell therapy, each kind of stem cell therapy has its own challenges: for example, hematopoietic stem cell therapy must be HLA matched; fetal stem cell involves ethical issues; tissue-derived stem cell and mesenchymal stem cell clinical trial cases are unstable; and based on pluripotent stem cell Cell therapy also has a lot of risks < / P > < p > therefore, the next generation of stem cell therapy came into being, which is based on the first and second generation stem cells through cell engineering technology transformation. Continue ReadingDeveloped a “plug and play” solar power generation scheme, and “5B” won a $12 million round a financing

Author: zmhuaxia