Jump up ^ Wollert, Kai C; Meyer, Gerd P; Müller-Ehmsen, Jochen; Tschöpe, Carsten; Bonarjee, Vernon; Larsen, Alf Inge; May, Andreas E; Empen, Klaus; Chorianopoulos, Emmanuel; Tebbe, Ulrich; Waltenberger, Johannes; Mahrholdt, Heiko; Ritter, Benedikta; Pirr, Jens; Fischer, Dieter; Korf-Klingebiel, Mortimer; Arseniev, Lubomir; Heuft, Hans-Gert; Brinchmann, Jan E; Messinger, Diethelm; Hertenstein, Bernd; Ganser, Arnold; Katus, Hugo A; Felix, Stephan B; Gawaz, Meinrad P; Dickstein, Kenneth; Schultheiss, Heinz-Peter; Ladage, Dennis; Greulich, Simon; Bauersachs, Johann (14 October 2017). "Intracoronary autologous bone marrow cell transfer after myocardial infarction: the BOOST-2 randomised placebo-controlled clinical trial". European Heart Journal. 38 (39): 2936–2943. doi:10.1093/eurheartj/ehx188.
The ultimate goal is for the cells to take up residence in their proper places in the body, divide repeatedly and form functioning tissues—or repair diseased tissue. It’s not always clear how this happens. In some cases, the transplanted cells may become part of the tissue or organ; in others, they may secrete growth factors that stimulate cells already residing there.
How a plant functions in nature is completely unrelated to how human skin works, not to mention that these claims are without substantiation. How well a plant survives in the desert or in a miserably cold climate doesn’t apply to us because no matter how you slather such products on your skin, you still won’t survive long without specific nutrients, shade, clothing, and other skin-protective factors, which plants just don’t need to worry about.

Other types of stem cells are found at various locations in the body. In particular, we can find populations of stem cells in organs that usually repair themselves very quickly. The cell layers on the inside of the intestines are renewed every few days by stem cells that are present in the intestines. These stem cells divide and the new cells (called daughter cells) form new layers of intestinal cells. The outer layers of the skin are also continuously renewed, and skin stem cells are responsible for this process. Finally, throughout the body we can find so-called mesenchymal stem cellsCell that forms fat cells, bone cells, cartilage cells, and muscle cells.. These cells form bone, cartilage, fat, and muscle. An overview of the different stem cell types is shown in Figure 1.

androgenetic alopecia  a progressive, diffuse, symmetric loss of scalp hair, believed due to a combination of genetic predisposition and increased response of hair follicles to androgens, in men beginning around age 30 with hair loss from the vertex and frontoparietal regions (male pattern a. or male pattern baldness), and in females beginning later with less severe hair loss in the frontocentral area of the scalp.

In theory, stem cells taken from the patient could be coaxed in the lab turning into a tooth bud which, when implanted in the gums, will give rise to a new tooth, and would be expected to be grown in a time over three weeks.[40] It will fuse with the jawbone and release chemicals that encourage nerves and blood vessels to connect with it. The process is similar to what happens when humans grow their original adult teeth. Many challenges remain, however, before stem cells could be a choice for the replacement of missing teeth in the future.[41][42]
A barrier to overcome is to avoid the rejection of the implanted cells by the recipient. In fact, immunosuppressive drugs are associated with many highly unpleasant side effects, and such a treatment would not represent an optimally acceptable option. Interestingly, ES cells seem to express less immune-related cell surface proteins (e.g., class I products of the major histocompatibility complex) (51). Drukker et al. (52) addressed the graft rejection issue of cells derived from hES cells by showing that both undifferentiated or differentiated hES express no major histocompatibility complex (MHC)-II proteins or human leukocyte antigen (HLA)-G and very low levels of MHC class I (MHC-I) proteins on their surface. MHC-I molecules, however, may be dramatically and rapidly induced by treating the cells with interferons. If a similar phenomenon occurs after transplantation, allogeneic human ES cells might be rejected by cytotoxic T lymphocytes.
In late 2007, scientists identified conditions that would allow some specialized adult human cells to be reprogrammed genetically to assume a stem cell-like state. These stem cells are called induced pluripotent stem cells (iPSCs). IPSCs are adult cells that have been genetically reprogrammed to an embryonic stem cell–like state by being forced to express genes and factors important for maintaining the defining properties of embryonic stem cells. Although these cells meet the defining criteria for pluripotent stem cells, it is not known if iPSCs and embryonic stem cells differ in clinically significant ways. Mouse iPSCs were first reported in 2006, and human iPSCs were first reported in late 2007. Mouse iPSCs demonstrate important characteristics of pluripotent stem cells, including expressing stem cell markers, forming tumors containing cells from all three germ layers, and being able to contribute to many different tissues when injected into mouse embryos at a very early stage in development. Human iPSCs also express stem cell markers and are capable of generating cells characteristic of all three germ layers.

When healthy hair is pulled out, at most a few should come out, and ripped hair should not be distributed evenly across the tugged portion of the scalp. In cases of alopecia areata, hair will tend to pull out more easily along the edge of the patch where the follicles are already being attacked by the body's immune system than away from the patch where they are still healthy.[11]
Stem cells have been used to treat degenerative bone diseases. The normally recommended treatment for dogs that have Legg–Calve–Perthes disease is to remove the head of the femur after the degeneration has progressed. Recently, mesenchymal stem cells have been injected directly in to the head of the femur, with success not only in bone regeneration, but also in pain reduction.[87]
A plethora of research shows plant stem cells contain different phytochemicals with anti-aging, anti-oxidant and healing potential. Current trends in dermatology research and development along with consumer interest in beauty suggest that the trend in plant stem cell-based cosmetics is here to stay, and will likely include human stem cells in the near future. As the cosmetics industry is rapidly evolving, try researching the ingredients in the stem cell-based cosmetics before you commit to the product.
The Institute for Biotechnological Research (IRB) has released an anti-aging ingredient based on edelweiss stem cells.  "As edelweiss grows in harsh climates it is obliged to produce a number of active substances that help protect against the elements such as UV rays," IRB's Francesca Melandri says.  The edelweiss active harnesses the protective substances the plant uses to defend itself against harsh climatic and environmental conditions and uses them to protect the skin,. According to the Italian company. the ingredient, Leontopodium alpinum stems, has high concentrations of leontopodic acids A and B which have strong antioxidant properties. IRB also claims the product has strong anti-collagenase and hyaluronidase actvity, therefore helping to limit the degradation of collagen and hyaluronic acid in the skin.
There is no cure for the condition.[2] Efforts may be used to try to speed hair regrowth such as cortisone injections.[1][2] Sunscreen, head coverings to protect from cold and sun, and glasses if the eyelashes are missing is recommended.[2] In some cases the hair regrows and the condition does not reoccur.[2] In others hair loss and regrowth occurs over years.[2] Among those in whom all body hair is lost less than 10% recover.[5]
A plethora of research shows plant stem cells contain different phytochemicals with anti-aging, anti-oxidant and healing potential. Current trends in dermatology research and development along with consumer interest in beauty suggest that the trend in plant stem cell-based cosmetics is here to stay, and will likely include human stem cells in the near future. As the cosmetics industry is rapidly evolving, try researching the ingredients in the stem cell-based cosmetics before you commit to the product.
The primary side effect of topical minoxidil therapy is hypertrichosis (excessive hair growth). The hair growth is most often noted above the eyebrows, in the malar region, and on the lateral cheeks. It occasionally occurs above the upper lip and on the chin. Facial hypertrichosis has been reported to affect 3 to 5 percent of women treated with the 2 percent solution and more than 5 percent of women treated with the 5 percent solution.8
The best characterized example of an adult stem cell is the blood stem cell (the hematopoietic stem cell). When we refer to a bone marrow transplant, a stem cell transplant, or a blood transplant, the cell being transplanted is the hematopoietic stem cell, or blood stem cell. This cell is a very rare cell that is found primarily within the bone marrow of the adult.
Embryonic stem cells of the inner cell mass are pluripotent, meaning they are able to differentiate to generate primitive ectoderm, which ultimately differentiates during gastrulation into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. These include each of the more than 220 cell types in the adult human body. Pluripotency distinguishes embryonic stem cells from adult stem cells, which are multipotent and can only produce a limited number of cell types.
Immunomodulating agents used in the treatment of alopecia areata include corticosteroids, 5 percent minoxidil, and anthralin cream (Psoriatec). Topical immunotherapeutic agents (e.g., dinitrochlorobenzene, squaric acid dibutyl ester, and diphenylcyclopropenone) are also used, although management regimens for these potent agents are challenging. Dermatology consultation or referral may be necessary. All of these agents stimulate hair growth but do not prevent hair loss. Moreover, they probably do not influence the course of the disease.
XtemCell's patented stem cell technology uses active plant cells from rare, 100% organic, nutrient-rich plants to create new cells high in purity and nutrients rather than using the traditional technique utilizing harsh chemicals for extraction. This patented technology ensures high concentrations of lipids, proteins, amino acids and phytoalexins [18]. According to the company, clinical testing has proven that the active cells used in XtemCell's products are easily absorbed into the outermost cells of the epidermis, allowing almost instantaneous skin cell renewal, nutrient absorption and an increase in the skin's level of filaggrin proteins to protect the skin from further sun and aging damage when applied [19,20].
Although the name might sound off-putting, there’s nothing taboo about plant stem cells. This nature-derived ingredient is a beneficial part of skin care and something you want to start paying attention to when it comes to your anti-aging routine. Using products that contain plant stem cells can help keep your skin looking young by fighting off wrinkles, protecting against sun damage and reducing inflammation. 
Mouse ES cells can be put back into a mouse blastocyst and this blastocyst can then be returned to the uterus of a female mouse to develop into a foetus. The injected ES cells take part in the development of the foetus and the resulting pup is born with a mixture of cells, (a) from the host blastocyst and (b) cells that came from the injected ES cells. This new mouse with cells from two different origins is known as a chimera. 
A key aspect of hair loss with age is the aging of the hair follicle.[43] Ordinarily, hair follicle renewal is maintained by the stem cells associated with each follicle. Aging of the hair follicle appears to be primed by a sustained cellular response to the DNA damage that accumulates in renewing stem cells during aging.[44] This damage response involves the proteolysis of type XVII collagen by neutrophil elastase in response to the DNA damage in the hair follicle stem cells. Proteolysis of collagen leads to elimination of the damaged cells and then to terminal hair follicle miniaturization.
The way in which hES cells could be used to treat heart disease has already been tested in mice and rats. Mouse ES cells, when cultivated as embryoid bodies, are able to differentiate in vitro into cardiomyocytes of ventricle-, atrium-, and pacemaker-like cell types characterized by developmentally controlled expression of cardiac-specific genes, structural proteins, sarcomeric proteins (74,75), and ion channels (8,76,77). Since only approximately 5% of the cell population within embryoid bodies are cardiomyocytes, the selection of an enriched culture of cardiomyocytes has required genetic manipulation (47,49,50). Clearly, the purity of differentiated ES-derived cardiomyocyte culture is a key issue to avoid the potential formation of teratomas, which would disrupting heart contractility.
Embryonic stem cells are derived from the inner cell mass of the early embryo, which are harvested from the donor mother animal. Martin Evans and Matthew Kaufman reported a technique that delays embryo implantation, allowing the inner cell mass to increase. This process includes removing the donor mother's ovaries and dosing her with progesterone, changing the hormone environment, which causes the embryos to remain free in the uterus. After 4–6 days of this intrauterine culture, the embryos are harvested and grown in in vitro culture until the inner cell mass forms “egg cylinder-like structures,” which are dissociated into single cells, and plated on fibroblasts treated with mitomycin-c (to prevent fibroblast mitosis). Clonal cell lines are created by growing up a single cell. Evans and Kaufman showed that the cells grown out from these cultures could form teratomas and embryoid bodies, and differentiate in vitro, all of which indicating that the cells are pluripotent.[41]
A few small studies have also been carried out in humans, usually in patients who are undergoing open-heart surgery. Several of these have demonstrated that stem cells that are injected into the circulation or directly into the injured heart tissue appear to improve cardiac function and/or induce the formation of new capillaries. The mechanism for this repair remains controversial, and the stem cells likely regenerate heart tissue through several pathways. However, the stem cell populations that have been tested in these experiments vary widely, as do the conditions of their purification and application. Although much more research is needed to assess the safety and improve the efficacy of this approach, these preliminary clinical experiments show how stem cells may one day be used to repair damaged heart tissue, thereby reducing the burden of cardiovascular disease.
Due to their plasticity and potentially unlimited capacity for self-renewal, embryonic stem cell therapies have been proposed for regenerative medicine and tissue replacement after injury or disease. Pluripotent stem cells have shown potential in treating a number of varying conditions, including but not limited to: spinal cord injuries, age related macular degeneration, diabetes, neurodegenerative disorders (such as Parkinson's disease), AIDS, etc.[7] In addition to their potential in regenerative medicine, embryonic stem cells provide an alternative source of tissue/organs which serves as a possible solution to the donor shortage dilemma. Not only that, but tissue/organs derived from ESCs can be made immunocompatible with the recipient. Aside from these uses, embryonic stem cells can also serve as tools for the investigation of early human development, study of genetic disease and as in vitro systems for toxicology testing.[5]

The stem cells in beauty products are obtained primarily from plants and fruits that can stay fresh for a long time, like Swiss apples, edelweiss, roses, date palms, and gotu kola (a swamp plant). Extracts of these stem cells—not the live cells themselves—are added to skin-care products. “It’s not possible to maintain live stem cells in cosmetic emulsions,” says Zoe Diana Draelos, a consulting professor of dermatology at the Duke University School of Medicine, in Durham, North Carolina. If a product is labeled as a stem-cell cream or serum, you may see some of the stem cell’s key substances, such as ferulic acid, ellagic acid, and quercetin, listed on the ingredient panel. “To yield the most potent, stable extract, the fruits and the plants that are the source of the stem cells must be cultivated in a controlled environment, without any contaminants,” says Draelos. This unique and precise extraction technology can drive the cost of these products to $100 and upward.
Diphencyprone (DPCP): This medicine is applied to the bald skin. It causes a small allergic reaction. When the reaction occurs, a patient has redness, swelling, and itching. Dermatologists believe this allergic reaction tricks the immune system, causing it to send white blood cells to the surface of the scalp. This fights the inflammation. It also prevents the hair follicles from going to sleep, and causing the hair loss.
Because embryonic stem cells are immature cells that multiply very rapidly, they often form tumors - a significant hurdle at present for human therapeutic use. Embryonic cells are most often used in research to model “diseases in a dish” to test or identify new drugs for the treatment of disease. The 2006 discovery that adult skin cells could be reprogrammed to behave like pluripotent stem cells largely leapfrogged the use of embryonic cells for clinical development.
Annually, many thousands of infertile couples create embryos for in-vitro fertilization (IVF), by having their eggs and sperm mixed and fertilized in a petri dish. Usually the potential mother is stimulated with hormones and provides a number of eggs. Similarly, the potential father has millions of sperm in his ejaculated semen. Normally all the eggs are exposed to sperm and a number of become fertilized and become embryos. The best looking embryos are incubated long enough to become blastocysts. Usually three are implanted into the potential mother's uterus. The remaining embryos are stored in liquid nitrogen in case of pregnancy failure or for later use if the family wants another child. These embryos are stored in cryobanks. Many of them eventually become available for research. With informed donor consent from both parents, these frozen embryos have the potential for providing most of the necessary raw material for stem cell research.
Adipose-derived mesenchymal cells are currently the most often used because of the non-invasive harvesting. There has been a lot of success recently injecting mesenchymal stem cells directly into the joint. This is a recently developed, non-invasive technique developed for easier clinical use. Dogs receiving this treatment showed greater flexibility in their joints and less pain.[92]
Umbilical cord blood stem cell transplants are less prone to rejection than either bone marrow or peripheral blood stem cells. This is probably because the cells have not yet developed the features that can be recognized and attacked by the recipient's immune system. Also, because umbilical cord blood lacks well-developed immune cells, there is less chance that the transplanted cells will attack the recipient's body, a problem called graft versus host disease.
Additionally, replacement cells and tissues may be used to treat brain disease such as Parkinson's and Alzheimer's by replenishing damaged tissue, bringing back the specialized brain cells that keep unneeded muscles from moving. Embryonic stem cells have recently been directed to differentiate into these types of cells, and so treatments are promising.
Embryonic stem cells are pluripotent stem cells derived from the inner cell mass of blastocysts. Under specific culture conditions, embryonic stem cells can differentiate into cell types from all three germ layers, and they generate, for example, endothelial cells, vascular smooth muscle cells, and cardiomyocytes; this makes them an attractive source for cardiac cell therapy and tissue engineering. Human embryonic stem cell–derived cardiomyocytes display structural and functional properties of early-stage cardiomyocytes that couple with host cardiomyocytes when transplanted into normal or infarcted myocardium. The first reports demonstrated their potential to function as biological pacemakers. More recent data have shown that transplantation of sufficient numbers of cardiac-committed murine embryonic stem cells into infarcted sheep myocardium can promote improvements in systolic function. In theory, infinite numbers of cardiomyocytes could be obtained from human embryonic stem cell clones. However, unresolved ethical and legal issues, concerns about the tumorigenicity of residual embryonic stem cells in embryonic stem cell–derived cardiomyocyte preparations, and the need to use allogeneic cells for transplantation currently hamper their use in clinical studies. It is important to refine cell differentiation and isolation protocols that yield highly purified cell populations for transplantation. This could best be achieved by cell sorting by means of cell type–specific membrane markers; alternative approaches might include genetic methods involving cell type–specific promoter constructs that drive the expression of marker proteins or selected survival by antibiotic resistance.
The specificity of the human immune-cell repertoire is what allows the human body to defend itself from rapidly adapting antigens. However, the immune system is vulnerable to degradation upon the pathogenesis of disease, and because of the critical role that it plays in overall defense, its degradation is often fatal to the organism as a whole. Diseases of hematopoietic cells are diagnosed and classified via a subspecialty of pathology known as hematopathology. The specificity of the immune cells is what allows recognition of foreign antigens, causing further challenges in the treatment of immune disease. Identical matches between donor and recipient must be made for successful transplantation treatments, but matches are uncommon, even between first-degree relatives. Research using both hematopoietic adult stem cells and embryonic stem cells has provided insight into the possible mechanisms and methods of treatment for many of these ailments.[citation needed]
Bone marrow and peripheral blood stem cell transplants have been utilized for over 40 years as therapy for blood disorders such as leukemia and lymphoma, amongst many others.  Scientists have also shown that stem cells reside in most tissues of the body and research continues to learn how to identify, extract, and proliferate these cells for further use in therapy.  Scientists hope to yield therapies for diseases such as type I diabetes and repair of heart muscle following heart attack.
Treatment with anthralin, a nonspecific immunomodulator, is safe and effective, particularly in patients with widespread alopecia areata. Anthralin is available in 0.1, 0.25, 0.5, and 1.0 percent creams, which can be applied once daily at home for progressively longer periods, starting with five minutes at a time and working up to as long as one hour. After each application period, the scalp is rinsed thoroughly with cool to lukewarm water and then cleaned with soap. New hair growth becomes apparent in two to three months. Approximately 25 percent of patients have cosmetically acceptable results within six months.18
It has been shown that adult human fibroblasts can be reprogrammed to a pluripotent state by retroviral transduction of four transcription factors (a combination of OCT4, SOX2, KLF4, and Myc, or a combination of OCT4, SOX2, NANOG, and LIN28). By genetic and developmental criteria, these induced pluripotent stem (iPS) cells are very similar to embryonic stem cells: They can be maintained in culture for several months and can be induced to differentiate into derivatives of all three germ layers. It has been shown that iPS cells have the potential to differentiate into functional cardiomyocytes, with a gene expression profile and electrophysiological properties that are similar to those of embryonic stem cell–derived cardiomyocytes. In the future, iPS cells may allow derivation of autologous cardiomyocytes and vascular cells for myocardial cell therapy and tissue engineering (Figure 51-1). Safety issues such as the risks of teratoma formation or insertional activation of proto-oncogenes after retroviral transduction must be addressed, and strategies to create “virus-free” iPS are currently being developed in several laboratories.
The company says that the products escape the health risk warning flags out because they do not affect the growth of stem cells. However, the products formulated by Decouverte Cosmetique may be particularly controversial from an ethical or moral point of view because the active ingredient is sourced from human embryonic stem cells. However, National Stem Cell says that all the stem cells used were harvested before 2001 and none were destroyed or created in the development of the products. The company is also in the final stages of discovering how to source the key material from non-embryonic stem cells thereby weakening the ethical barrier to commercialization. 8
Stem cells from plants are one of the newest anti-aging ingredients. Plant stem cells have garnered attention because they are immortal, and who wouldn’t want some of that? As a cosmetic ingredient, plant stem cell technology is still new, lacks ample independent research to back it up and is dominated by the so-called “rare Swiss apple” stem cell. But there is a sense that we are at the cutting edge with new plant stem cells from lilac to edelweiss, all of which are backed by some clinical trials and a host of new anti-aging products that feature them. Here is a guide to how they work, the different types that are becoming available and which products you can find them in.
And new sources of ES cells have presented other research tools for genetic disease. In 2004, for example, fertility doctors in Chicago started making ES-cell lines from embryos created through in vitro fertilization that had been found to have a genetic defect, and thus were rejected for fertility treatments. This allowed the team to create cellular models of thalassaemia, Huntington’s disease, Marfan’s syndrome, muscular dystrophy and other genetic conditions13. In 2007, researchers used ES cells to pin down the molecular changes that lead to cognitive impairments seen in a heritable condition known as Fragile X syndrome14.

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The best and most readily understood example of a stem cell in humans is that of the fertilized egg, or zygote. A zygote is a single cell that is formed by the union of a sperm and ovum. The sperm and the ovum each carry half of the genetic material required to form a new individual. Once that single cell or zygote starts dividing, it is known as an embryo. One cell becomes two, two become four, four become eight, eight become sixteen, and so on, doubling rapidly until it ultimately grows into an entire sophisticated organism composed of many different kinds of specialized cells. That organism, a person, is an immensely complicated structure consisting of many, many, billions of cells with functions as diverse as those of your eyes, your heart, your immune system, the color of your skin, your brain, etc. All of the specialized cells that make up these body systems are descendants of the original zygote, a stem cell with the potential to ultimately develop into all kinds of body cells. The cells of a zygote are totipotent, meaning that they have the capacity to develop into any type of cell in the body.
Scientists have also found stem cells in the placenta and in the umbilical cord of newborn infants, and they can isolate stem cells from different fetal tissues. Although these cells come from an umbilical cord or a fetus, they more closely resemble adult stem cells than embryonic stem cells because they are tissue-specific. The cord blood cells that some people bank after the birth of a child are a form of adult blood-forming stem cells.
Research is looking into connections between hair loss and other health issues. While there has been speculation about a connection between early-onset male pattern hair loss and heart disease, a review of articles from 1954 to 1999 found no conclusive connection between baldness and coronary artery disease. The dermatologists who conducted the review suggested further study was needed.[41]

Traumatic alopecia can be caused by cosmetic practices that damage hair follicles over time.7 Cosmetic alopecia has been linked to the use of brush rollers, curling irons, hair brushes with square or angular tips, and tight braiding of the hair (Figure 6). Chemicals used repetitively on the hair also can damage follicles. Examination of the scalp shows short broken hairs, folliculitis and, frequently, scarring.
To realize the full potential of human pluripotent stem cells, challenging research lies ahead and several practical issues must be resolved. The conditions necessary to derive human ES cells efficiently and reliably must be defined. How did the Thomson group succeed when, on the surface, their protocol is so similar to that of other investigators? Their previous experience with nonhuman primate ES cell derivation was certainly critical for this success. Thomson et al. (11) report that of 14 inner cell masses placed in culture, five ES cell lines were established. This result is excellent, but could it be better? Are there ways of assaying blastocysts for their potential of yielding ES cells? As in the mouse, are there predisposing genes for this property? Are there other extrinsic or intrinsic factors that may lead to a greater success rate?
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
These possess the capacity to divide for long periods and retain their ability to make all cell types within the organism. The best known type of pluripotent stem cell is the one present in embryos that helps babies grow within the womb. These are termed embryonic stem cells. These cells form at the blastocyst stage of development. A blastocyst is a hollow ball of cells that is smaller than a pinhead. The embryonic stem cells lie within this ball of cells. Recent research has enabled scientists to derive pluripotent cells from adult human skin cells. These are termed induced pluripotent stem cells or iPS cells.
Nearly all research to date has made use of mouse embryonic stem cells (mES) or human embryonic stem cells (hES) derived from the early inner cell mass. Both have the essential stem cell characteristics, yet they require very different environments in order to maintain an undifferentiated state. Mouse ES cells are grown on a layer of gelatin as an extracellular matrix (for support) and require the presence of leukemia inhibitory factor (LIF) in serum media. A drug cocktail containing inhibitors to GSK3B and the MAPK/ERK pathway, called 2i, has also been shown to maintain pluripotency in stem cell culture.[14] Human ESCs are grown on a feeder layer of mouse embryonic fibroblasts and require the presence of basic fibroblast growth factor (bFGF or FGF-2).[15] Without optimal culture conditions or genetic manipulation,[16] embryonic stem cells will rapidly differentiate.
Most stem cells intended for regenerative therapy are generally isolated either from the patient's bone marrow or from adipose tissue.[61][63] Mesenchymal stem cells can differentiate into the cells that make up bone, cartilage, tendons, and ligaments, as well as muscle, neural and other progenitor tissues, they have been the main type of stem cells studied in the treatment of diseases affecting these tissues.[67][68] The number of stem cells transplanted into damaged tissue may alter efficacy of treatment. Accordingly, stem cells derived from bone marrow aspirates, for instance, are cultured in specialized laboratories for expansion to millions of cells.[61][63] Although adipose-derived tissue also requires processing prior to use, the culturing methodology for adipose-derived stem cells is not as extensive as that for bone marrow-derived cells.[69][70] While it is thought that bone-marrow derived stem cells are preferred for bone, cartilage, ligament, and tendon repair, others believe that the less challenging collection techniques and the multi-cellular microenvironment already present in adipose-derived stem cell fractions make the latter the preferred source for autologous transplantation.[60]
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Stem cells from bone marrow have been used since the 1950s to treat patients with certain types of blood cancer like leukemia or lymphoma. Donating stem cells can now be as easy as donating blood. Umbilical cord blood collected at birth also provides an abundant source of bone marrow stem cells and is often used to treat cancer and rare inherited disorders in children.

Growing cells in the laboratory is known as cell culture. Human embryonic stem cells (hESCs) are generated by transferring cells from a preimplantation-stage embryo into a plastic laboratory culture dish that contains a nutrient broth known as culture medium. The cells divide and spread over the surface of the dish. In the original protocol, the inner surface of the culture dish was coated with mouse embryonic skin cells specially treated so they will not divide. This coating layer of cells is called a feeder layer. The mouse cells in the bottom of the culture dish provide the cells a sticky surface to which they can attach. Also, the feeder cells release nutrients into the culture medium. Researchers have now devised ways to grow embryonic stem cells without mouse feeder cells. This is a significant scientific advance because of the risk that viruses or other macromolecules in the mouse cells may be transmitted to the human cells.