STEM CELLS 

   Stem cells are clonal cells that have the potential for self-renewal, can be directed to different cell types, and can be patched. Many cells of the body (heart cell, skin cell, etc.) are conditioned for a special function. The stem cell, on the other hand, is unconditioned and remains unconditioned until it receives a stimulus to transform into a special cell. Their ability to reproduce and customize makes stem cells very special.

   There are many different types of stem cells available. Among these are embryonic stem cells, which exist only in the early stages of development, and 'tissue-specific' stem cells (sometimes referred to as 'adult' or 'somatic' stem cells) found in different tissues in our body. Recently, cells with similar characteristics to embryonic stem cells have been developed from specialized cells such as skin cells. At the same time, fetal stem cells are taken from fetuses that have had abortion or were taken as a result of some disabilities.

WHERE ARE STEM CELL OBTAINED FROM?

Embryonic Stem Cells

   

Embryonic stem cells are usually obtained from the inner cell mass consisting of approximately 30 cells of embryos that have differentiated into trophoblast and inner cell mass at the blastocyst stage. Embryonic stem cells, which show unlimited division and differentiation ability, promise a wide range of use in biomedical research and regenerative medicine. Constructing these cells to adapt to the recipient can eliminate implant rejection and constraints on donor tissue provisioning. Twenty years ago, two different research groups were able to separate embryonic stem cells from mouse blastocysts and keep them in culture. Since this date, studies on the use of stem cells for therapeutic purposes continue with the improvement of culture conditions, embryo manipulation techniques and developments in developmental biology. Currently, studies in human embryos are carried out in embryos donated in in-vitro fertilization clinics. The first embryonic stem cells derived from human blastocysts were found in 1994 by Bongso et al. reported by Thomson et al. obtained the first human stem cell line and embryonic stem cell lines were produced by various researchers. In the following period, studies were carried out to direct differentiation and to create various embryonic stem cell lines. Apart from cell therapy, these cells can also be used as an in vitro system for investigating the effects of new drugs and identifying genes that are potential therapeutic targets.

Characteristics of Embryonic Stem Cells

Embryonic stem cells are pluripotent cells. That is, they show the ability to differentiate into three main tissues such as endoderm, ectoderm and mesoderm. Embryonic stem cell lines can be obtained from adult cells by somatic cell nuclear transfer. The embryonic stem cells thus obtained can differentiate into many cell types in vitro, including neurons, and into germ cells in vivo.

Fetus Stem Cell

    Stem cells can also be obtained from cells taken from women who had a miscarriage. These stem cells have the ability to divide and renew themselves an unlimited number of times. These cells, which reproduce by division, have the same genetic structure. In other words, they reproduce and form cells just like themselves. These cells obtained from embryos are pluripotent, that is, they can turn into any cell type such as muscle, nerve, liver when necessary conditions are met. These cells can differentiate again and reduce their chromosome number to half and turn into egg or sperm cells. However, some of them are not able to create a new organism, that is, they are not "totipotent". In the organism that has grown a little more in the uterus, reproductive cells that will become sperm or eggs in the future can also be used as stem cells. These cells can also transform into all cell types in culture medium. In other words, they show similar behavior to embryonic stem cells. For this reason, they are used as an alternative to embryonic stem cells in scientific studies. However, since these stem cells obtained from the fetus are at a later stage of development, their potential for proliferation is somewhat lower. Fetuses obtained from women who had miscarriage or fetuses that were terminated due to various disabilities are sources for such stem cells.

Adult Stem Cells

Adult stem cells are cells that have the capacity to renew themselves for a long time and differentiate into progenitor cells in adult tissues. Progenitor cells are partially differentiated cells and can differentiate into certain cell lines, they do not have the ability to renew themselves. There is no definite judgment about the origins of adult stem cells yet. Some researchers suggest that there are cells that retain their properties during fetal development. When examining adult stem cells, it is very difficult to distinguish tissue-specific stem cells from progenitor cells. Hemapoietic stem cells, bone marrow stromal stem cells, cord blood stem cells, endothelial progenitor cells, skeletal muscle stem cells, epithelial precursor cells in the skin and digestive system, stem cells in the pancreas, liver, cornea, retina, tooth root, spinal cord and brain. Various studies are carried out in different tissues, including Bone marrow stem cells have been used for transplantation for about 30 years.

Characteristics of Adult Stem Cells

By definition, adult stem cells are cells that maintain the ability to renew themselves throughout the life of the organism. The number of adult stem cells is limited, they take part in maintaining the balance in the tissue by directing the cells that will replace the cells damaged as a result of injury or disease. However, it cannot be produced under culture conditions by preserving its properties for as long as embryonic stem cells. They are spread throughout the body and are oriented differently according to the microenvironmental conditions they are in. For example, hematopoietic stem cells are responsible for the formation of blood cells in the bone marrow. Because adult stem cells do not have a specific location, they are not easy to obtain.

Factors Limiting the Use of Therapy in Stem Cells

o Trials on humans are still insufficient, and some treatments have never been tested on humans,

o The risk of transplanted stem cells to form cancer in the tissue,

o The fact that stem cells are not accepted by the tissue is among the factors limiting stem cell therapy.

Usage Areas of Stem Cell

o Cardiovascular and Lung Diseases

o Musculoskeletal Diseases

o Endocrine System Diseases

o Nervous System Diseases

o Parkinson's Disease

o Cancer treatment

o Graft Versus Host disease (organ dysfunction as a result of severe immunological reaction mediated by T-lymphocytes)

o Orthopedic defects

o Aesthetic surgery

o Blood diseases

How to donate stem cells?

   Any healthy person between the ages of 18 and 50 can become a stem cell donor. Root collected from peripheral blood, that is, the passenger, is the most commonly used method. In this method of donating blood, rooting can be carried out to be grown twice a day for the donor during the day. While eating in the arm, the catheter travels through the vein, taking the blood into a special machine. It stays connected to the machine for about 2 to 4 hours. There is no risk for the donor for these procedures. The taken student is informed in detail in pre-school education or by freezing. One method is bone marrow. The donation money will be spent from the donor to the donor. The donor is anesthetized with general anesthesia. Root-oriented pelvis by automatically entering the area with a small needle through the pelvic origin. The donor is discharged on the same day.

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