Category Archives: Stem Cells

Stem cell facts

What are stem cells?

Stem cells are cells that have the potential to develop into many different or specialized cell types. Stem cells can be thought of as primitive, "unspecialized" cells that are able to divide and become specialized cells of the body such as liver cells, muscle cells, blood cells, and other cells with specific functions. Stem cells are referred to as "undifferentiated" cells because they have not yet committed to a developmental path that will form a specific tissue or organ. The process of changing into a specific cell type is known as differentiation. In some areas of the body, stem cells divide regularly to renew and repair the existing tissue. The bone marrow and gastrointestinal tract are examples of areas in which stem cells function to renew and repair tissue.

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.

The process by which stem cells commit to become differentiated, or specialized, cells is complex and involves the regulation of gene expression. Research is ongoing to further understand the molecular events and controls necessary for stem cells to become specialized cell types.

Stem Cells:One of the human body's master cells, with the ability to grow into any one of the body's more than 200 cell types.

All stem cells are unspecialized (undifferentiated) cells that are characteristically of the same family type (lineage). They retain the ability to divide throughout life and give rise to cells that can become highly specialized and take the place of cells that die or are lost.

Stem cells contribute to the body's ability to renew and repair its tissues. Unlike mature cells, which are permanently committed to their fate, stem cells can both renew themselves as well as create new cells of whatever tissue they belong to (and other tissues).

Why are stem cells important?

Stem cells represent an exciting area in medicine because of their potential to regenerate and repair damaged tissue. Some current therapies, such as bone marrow transplantation, already make use of stem cells and their potential for regeneration of damaged tissues. Other therapies that are under investigation involve transplanting stem cells into a damaged body part and directing them to grow and differentiate into healthy tissue.

Embryonic stem cells

During the early stages of embryonic development the cells remain relatively undifferentiated (immature) and appear to possess the ability to become, or differentiate, into almost any tissue within the body. For example, cells taken from one section of an embryo that might have become part of the eye can be transferred into another section of the embryo and could develop into blood, muscle, nerve, or liver cells.

Cells in the early embryonic stage are totipotent (see above) and can differentiate to become any type of body cell. After about seven days, the zygote forms a structure known as a blastocyst, which contains a mass of cells that eventually become the fetus, as well as trophoblastic tissue that eventually becomes the placenta. If cells are taken from the blastocyst at this stage, they are known as pluripotent, meaning that they have the capacity to become many different types of human cells. Cells at this stage are often referred to as blastocyst embryonic stem cells. When any type of embryonic stem cells is grown in culture in the laboratory, they can divide and grow indefinitely. These cells are then known as embryonic stem cell lines.

Fetal stem cells

The embryo is referred to as a fetus after the eighth week of development. The fetus contains stem cells that are pluripotent and eventually develop into the different body tissues in the fetus.

Adult stem cells

Adult stem cells are present in all humans in small numbers. The adult stem cell is one of the class of cells that we have been able to manipulate quite effectively in the bone marrow transplant arena over the past 30 years. These are stem cells that are largely tissue-specific in their location. Rather than typically giving rise to all of the cells of the body, these cells are capable of giving rise only to a few types of cells that develop into a specific tissue or organ. They are therefore known as multipotent stem cells. Adult stem cells are sometimes referred to as somatic stem cells.

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.

One of the exciting discoveries of the last years has been the overturning of a long-held scientific belief that an adult stem cell was a completely committed stem cell. It was previously believed that a hematopoietic, or blood-forming stem cell, could only create other blood cells and could never become another type of stem cell. There is now evidence that some of these apparently committed adult stem cells are able to change direction to become a stem cell in a different organ. For example, there are some models of bone marrow transplantation in rats with damaged livers in which the liver partially re-grows with cells that are derived from transplanted bone marrow. Similar studies can be done showing that many different cell types can be derived from each other. It appears that heart cells can be grown from bone marrow stem cells, that bone marrow cells can be grown from stem cells derived from muscle, and that brain stem cells can turn into many types of cells.

Peripheral blood stem cells

Most blood stem cells are present in the bone marrow, but a few are present in the bloodstream. This means that these so-called peripheral blood stem cells (PBSCs) can be isolated from a drawn blood sample. The blood stem cell is capable of giving rise to a very large number of very different cells that make up the blood and immune system, including red blood cells, platelets, granulocytes, and lymphocytes.

All of these very different cells with very different functions are derived from a common, ancestral, committed blood-forming (hematopoietic), stem cell.

Umbilical cord stem cells

Blood from the umbilical cord contains some stem cells that are genetically identical to the newborn. Like adult stem cells, these are multipotent stem cells that are able to differentiate into certain, but not all, cell types. For this reason, umbilical cord blood is often banked, or stored, for possible future use should the individual require stem cell therapy.

Induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) were first created from human cells in 2007. These are adult cells that have been genetically converted to an embryonic stem celllike state. In animal studies, iPSCs have been shown to possess characteristics of pluripotent stem cells. Human iPSCs can differentiate and become multiple different fetal cell types. iPSCs are valuable aids in the study of disease development and drug treatment, and they may have future uses in transplantation medicine. Further research is needed regarding the development and use of these cells.

Why is there controversy surrounding the use of stem cells?

Embryonic stem cells and embryonic stem cell lines have received much public attention concerning the ethics of their use or non-use. Clearly, there is hope that a large number of treatment advances could occur as a result of growing and differentiating these embryonic stem cells in the laboratory. It is equally clear that each embryonic stem cell line has been derived from a human embryo created through in-vitro fertilization (IVF) or through cloning technologies, with all the attendant ethical, religious, and philosophical problems, depending upon one's perspective.

What are some stem cell therapies that are currently available?

Routine use of stem cells in therapy has been limited to blood-forming stem cells (hematopoietic stem cells) derived from bone marrow, peripheral blood, or umbilical cord blood. Bone marrow transplantation is the most familiar form of stem cell therapy and the only instance of stem cell therapy in common use. It is used to treat cancers of the blood cells (leukemias) and other disorders of the blood and bone marrow.

In bone marrow transplantation, the patient's existing white blood cells and bone marrow are destroyed using chemotherapy and radiation therapy. Then, a sample of bone marrow (containing stem cells) from a healthy, immunologically matched donor is injected into the patient. The transplanted stem cells populate the recipient's bone marrow and begin producing new, healthy blood cells.

Umbilical cord blood stem cells and peripheral blood stem cells can also be used instead of bone marrow samples to repopulate the bone marrow in the process of bone marrow transplantation.

In 2009, the California-based company Geron received clearance from the U. S. Food and Drug Administration (FDA) to begin the first human clinical trial of cells derived from human embryonic stem cells in the treatment of patients with acute spinal cord injury.

What are experimental treatments using stem cells and possible future directions for stem cell therapy?

Stem cell therapy is an exciting and active field of biomedical research. Scientists and physicians are investigating the use of stem cells in therapies to treat a wide variety of diseases and injuries. For a stem cell therapy to be successful, a number of factors must be considered. The appropriate type of stem cell must be chosen, and the stem cells must be matched to the recipient so that they are not destroyed by the recipient's immune system. It is also critical to develop a system for effective delivery of the stem cells to the desired location in the body. Finally, devising methods to "switch on" and control the differentiation of stem cells and ensure that they develop into the desired tissue type is critical for the success of any stem cell therapy.

Researchers are currently examining the use of stem cells to regenerate damaged or diseased tissue in many conditions, including those listed below.

References

REFERENCE:

"Stem Cell Information." National Institutes of Health.

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Stem Cells - MedicineNet

Stem cell, an undifferentiated cell that can divide to produce some offspring cells that continue as stem cells and some cells that are destined to differentiate (become specialized). Stem cells are an ongoing source of the differentiated cells that make up the tissues and organs of animals and plants. There is great interest in stem cells because they have potential in the development of therapies for replacing defective or damaged cells resulting from a variety of disorders and injuries, such as Parkinson disease, heart disease, and diabetes. There are two major types of stem cells: embryonic stem cells and adult stem cells, which are also called tissue stem cells.

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cardiovascular disease: Cardiac stem cells

Cardiac stem cells, which have the ability to differentiate (specialize) into mature heart cells and therefore could be used to repair damaged or diseased heart tissue, have garnered significant interest in the development of treatments for heart disease and cardiac defects. Cardiac stem

Embryonic stem cells (often referred to as ES cells) are stem cells that are derived from the inner cell mass of a mammalian embryo at a very early stage of development, when it is composed of a hollow sphere of dividing cells (a blastocyst). Embryonic stem cells from human embryos and from embryos of certain other mammalian species can be grown in tissue culture.

The most-studied embryonic stem cells are mouse embryonic stem cells, which were first reported in 1981. This type of stem cell can be cultured indefinitely in the presence of leukemia inhibitory factor (LIF), a glycoprotein cytokine. If cultured mouse embryonic stem cells are injected into an early mouse embryo at the blastocyst stage, they will become integrated into the embryo and produce cells that differentiate into most or all of the tissue types that subsequently develop. This ability to repopulate mouse embryos is the key defining feature of embryonic stem cells, and because of it they are considered to be pluripotentthat is, able to give rise to any cell type of the adult organism. If the embryonic stem cells are kept in culture in the absence of LIF, they will differentiate into embryoid bodies, which somewhat resemble early mouse embryos at the egg-cylinder stage, with embryonic stem cells inside an outer layer of endoderm. If embryonic stem cells are grafted into an adult mouse, they will develop into a type of tumour called a teratoma, which contains a variety of differentiated tissue types.

Mouse embryonic stem cells are widely used to create genetically modified mice. This is done by introducing new genes into embryonic stem cells in tissue culture, selecting the particular genetic variant that is desired, and then inserting the genetically modified cells into mouse embryos. The resulting chimeric mice are composed partly of host cells and partly of the donor embryonic stem cells. As long as some of the chimeric mice have germ cells (sperm or eggs) that have been derived from the embryonic stem cells, it is possible to breed a line of mice that have the same genetic constitution as the embryonic stem cells and therefore incorporate the genetic modification that was made in vitro. This method has been used to produce thousands of new genetic lines of mice. In many such genetic lines, individual genes have been ablated in order to study their biological function; in others, genes have been introduced that have the same mutations that are found in various human genetic diseases. These mouse models for human disease are used in research to investigate both the pathology of the disease and new methods for therapy.

Extensive experience with mouse embryonic stem cells made it possible for scientists to grow human embryonic stem cells from early human embryos, and the first human stem cell line was created in 1998. Human embryonic stem cells are in many respects similar to mouse embryonic stem cells, but they do not require LIF for their maintenance. The human embryonic stem cells form a wide variety of differentiated tissues in vitro, and they form teratomas when grafted into immunosuppressed mice. It is not known whether the cells can colonize all the tissues of a human embryo, but it is presumed from their other properties that they are indeed pluripotent cells, and they therefore are regarded as a possible source of differentiated cells for cell therapythe replacement of a patients defective cell type with healthy cells. Large quantities of cells, such as dopamine-secreting neurons for the treatment of Parkinson disease and insulin-secreting pancreatic beta cells for the treatment of diabetes, could be produced from embryonic stem cells for cell transplantation. Cells for this purpose have previously been obtainable only from sources in very limited supply, such as the pancreatic beta cells obtained from the cadavers of human organ donors.

The use of human embryonic stem cells evokes ethical concerns, because the blastocyst-stage embryos are destroyed in the process of obtaining the stem cells. The embryos from which stem cells have been obtained are produced through in vitro fertilization, and people who consider preimplantation human embryos to be human beings generally believe that such work is morally wrong. Others accept it because they regard the blastocysts to be simply balls of cells, and human cells used in laboratories have not previously been accorded any special moral or legal status. Moreover, it is known that none of the cells of the inner cell mass are exclusively destined to become part of the embryo itselfall of the cells contribute some or all of their cell offspring to the placenta, which also has not been accorded any special legal status. The divergence of views on this issue is illustrated by the fact that the use of human embryonic stem cells is allowed in some countries and prohibited in others.

In 2009 the U.S. Food and Drug Administration approved the first clinical trial designed to test a human embryonic stem cell-based therapy, but the trial was halted in late 2011 because of a lack of funding and a change in lead American biotech company Gerons business directives. The therapy to be tested was known as GRNOPC1, which consisted of progenitor cells (partially differentiated cells) that, once inside the body, matured into neural cells known as oligodendrocytes. The oligodendrocyte progenitors of GRNOPC1 were derived from human embryonic stem cells. The therapy was designed for the restoration of nerve function in persons suffering from acute spinal cord injury.

Embryonic germ (EG) cells, derived from primordial germ cells found in the gonadal ridge of a late embryo, have many of the properties of embryonic stem cells. The primordial germ cells in an embryo develop into stem cells that in an adult generate the reproductive gametes (sperm or eggs). In mice and humans it is possible to grow embryonic germ cells in tissue culture with the appropriate growth factorsnamely, LIF and another cytokine called fibroblast growth factor.

Some tissues in the adult body, such as the epidermis of the skin, the lining of the small intestine, and bone marrow, undergo continuous cellular turnover. They contain stem cells, which persist indefinitely, and a much larger number of transit amplifying cells, which arise from the stem cells and divide a finite number of times until they become differentiated. The stem cells exist in niches formed by other cells, which secrete substances that keep the stem cells alive and active. Some types of tissue, such as liver tissue, show minimal cell division or undergo cell division only when injured. In such tissues there is probably no special stem-cell population, and any cell can participate in tissue regeneration when required.

The epidermis of the skin contains layers of cells called keratinocytes. Only the basal layer, next to the dermis, contains cells that divide. A number of these cells are stem cells, but the majority are transit amplifying cells. The keratinocytes slowly move outward through the epidermis as they mature, and they eventually die and are sloughed off at the surface of the skin. The epithelium of the small intestine forms projections called villi, which are interspersed with small pits called crypts. The dividing cells are located in the crypts, with the stem cells lying near the base of each crypt. Cells are continuously produced in the crypts, migrate onto the villi, and are eventually shed into the lumen of the intestine. As they migrate, they differentiate into the cell types characteristic of the intestinal epithelium.

Bone marrow contains cells called hematopoietic stem cells, which generate all the cell types of the blood and the immune system. Hematopoietic stem cells are also found in small numbers in peripheral blood and in larger numbers in umbilical cord blood. In bone marrow, hematopoietic stem cells are anchored to osteoblasts of the trabecular bone and to blood vessels. They generate progeny that can become lymphocytes, granulocytes, red blood cells, and certain other cell types, depending on the balance of growth factors in their immediate environment.

Work with experimental animals has shown that transplants of hematopoietic stem cells can occasionally colonize other tissues, with the transplanted cells becoming neurons, muscle cells, or epithelia. The degree to which transplanted hematopoietic stem cells are able to colonize other tissues is exceedingly small. Despite this, the use of hematopoietic stem cell transplants is being explored for conditions such as heart disease or autoimmune disorders. It is an especially attractive option for those opposed to the use of embryonic stem cells.

Bone marrow transplants (also known as bone marrow grafts) represent a type of stem cell therapy that is in common use. They are used to allow cancer patients to survive otherwise lethal doses of radiation therapy or chemotherapy that destroy the stem cells in bone marrow. For this procedure, the patients own marrow is harvested before the cancer treatment and is then reinfused into the body after treatment. The hematopoietic stem cells of the transplant colonize the damaged marrow and eventually repopulate the blood and the immune system with functional cells. Bone marrow transplants are also often carried out between individuals (allograft). In this case the grafted marrow has some beneficial antitumour effect. Risks associated with bone marrow allografts include rejection of the graft by the patients immune system and reaction of immune cells of the graft against the patients tissues (graft-versus-host disease).

Bone marrow is a source for mesenchymal stem cells (sometimes called marrow stromal cells, or MSCs), which are precursors to non-hematopoietic stem cells that have the potential to differentiate into several different types of cells, including cells that form bone, muscle, and connective tissue. In cell cultures, bone-marrow-derived mesenchymal stem cells demonstrate pluripotency when exposed to substances that influence cell differentiation. Harnessing these pluripotent properties has become highly valuable in the generation of transplantable tissues and organs. In 2008 scientists used mesenchymal stem cells to bioengineer a section of trachea that was transplanted into a woman whose upper airway had been severely damaged by tuberculosis. The stem cells were derived from the womans bone marrow, cultured in a laboratory, and used for tissue engineering. In the engineering process, a donor trachea was stripped of its interior and exterior cell linings, leaving behind a trachea scaffold of connective tissue. The stem cells derived from the recipient were then used to recolonize the interior of the scaffold, and normal epithelial cells, also isolated from the recipient, were used to recolonize the exterior of the trachea. The use of the recipients own cells to populate the trachea scaffold prevented immune rejection and eliminated the need for immunosuppression therapy. The transplant, which was successful, was the first of its kind.

Research has shown that there are also stem cells in the brain. In mammals very few new neurons are formed after birth, but some neurons in the olfactory bulbs and in the hippocampus are continually being formed. These neurons arise from neural stem cells, which can be cultured in vitro in the form of neurospheressmall cell clusters that contain stem cells and some of their progeny. This type of stem cell is being studied for use in cell therapy to treat Parkinson disease and other forms of neurodegeneration or traumatic damage to the central nervous system.

Following experiments in animals, including those used to create Dolly the sheep, there has been much discussion about the use of somatic cell nuclear transfer (SCNT) to create pluripotent human cells. In SCNT the nucleus of a somatic cell (a fully differentiated cell, excluding germ cells), which contains the majority of the cells DNA (deoxyribonucleic acid), is removed and transferred into an unfertilized egg cell that has had its own nuclear DNA removed. The egg cell is grown in culture until it reaches the blastocyst stage. The inner cell mass is then removed from the egg, and the cells are grown in culture to form an embryonic stem cell line (generations of cells originating from the same group of parent cells). These cells can then be stimulated to differentiate into various types of cells needed for transplantation. Since these cells would be genetically identical to the original donor, they could be used to treat the donor with no problems of immune rejection. Scientists generated human embryonic stem cells successfully from SCNT human embryos for the first time in 2013.

While promising, the generation and use of SCNT-derived embryonic stem cells is controversial for several reasons. One is that SCNT can require more than a dozen eggs before one egg successfully produces embryonic stem cells. Human eggs are in short supply, and there are many legal and ethical problems associated with egg donation. There are also unknown risks involved with transplanting SCNT-derived stem cells into humans, because the mechanism by which the unfertilized egg is able to reprogram the nuclear DNA of a differentiated cell is not entirely understood. In addition, SCNT is commonly used to produce clones of animals (such as Dolly). Although the cloning of humans is currently illegal throughout the world, the egg cell that contains nuclear DNA from an adult cell could in theory be implanted into a womans uterus and come to term as an actual cloned human. Thus, there exists strong opposition among some groups to the use of SCNT to generate human embryonic stem cells.

Due to the ethical and moral issues surrounding the use of embryonic stem cells, scientists have searched for ways to reprogram adult somatic cells. Studies of cell fusion, in which differentiated adult somatic cells grown in culture with embryonic stem cells fuse with the stem cells and acquire embryonic stem-cell-like properties, led to the idea that specific genes could reprogram differentiated adult cells. An advantage of cell fusion is that it relies on existing embryonic stem cells instead of eggs. However, fused cells stimulate an immune response when transplanted into humans, which leads to transplant rejection. As a result, research has become increasingly focused on the genes and proteins capable of reprogramming adult cells to a pluripotent state. In order to make adult cells pluripotent without fusing them to embryonic stem cells, regulatory genes that induce pluripotency must be introduced into the nuclei of adult cells. To do this, adult cells are grown in cell culture, and specific combinations of regulatory genes are inserted into retroviruses (viruses that convert RNA [ribonucleic acid] into DNA), which are then introduced to the culture medium. The retroviruses transport the RNA of the regulatory genes into the nuclei of the adult cells, where the genes are then incorporated into the DNA of the cells. About 1 out of every 10,000 cells acquires embryonic stem cell properties. Although the mechanism is still uncertain, it is clear that some of the genes confer embryonic stem cell properties by means of the regulation of numerous other genes. Adult cells that become reprogrammed in this way are known as induced pluripotent stem cells (iPS).

Similar to embryonic stem cells, induced pluripotent stem cells can be stimulated to differentiate into select types of cells that could in principle be used for disease-specific treatments. In addition, the generation of induced pluripotent stem cells from the adult cells of patients affected by genetic diseases can be used to model the diseases in the laboratory. For example, in 2008 researchers isolated skin cells from a child with an inherited neurological disease called spinal muscular atrophy and then reprogrammed these cells into induced pluripotent stem cells. The reprogrammed cells retained the disease genotype of the adult cells and were stimulated to differentiate into motor neurons that displayed functional insufficiencies associated with spinal muscular atrophy. By recapitulating the disease in the laboratory, scientists were able to study closely the cellular changes that occurred as the disease progressed. Such models promise not only to improve scientists understanding of genetic diseases but also to facilitate the development of new therapeutic strategies tailored to each type of genetic disease.

In 2009 scientists successfully generated retinal cells of the human eye by reprogramming adult skin cells. This advance enabled detailed investigation of the embryonic development of retinal cells and opened avenues for the generation of novel therapies for eye diseases. The production of retinal cells from reprogrammed skin cells may be particularly useful in the treatment of retinitis pigmentosa, which is characterized by the progressive degeneration of the retina, eventually leading to night blindness and other complications of vision. Although retinal cells also have been produced from human embryonic stem cells, induced pluripotency represents a less controversial approach. Scientists have also explored the possibility of combining induced pluripotent stem cell technology with gene therapy, which would be of value particularly for patients with genetic disease who would benefit from autologous transplantation.

Researchers have also been able to generate cardiac stem cells for the treatment of certain forms of heart disease through the process of dedifferentiation, in which mature heart cells are stimulated to revert to stem cells. The first attempt at the transplantation of autologous cardiac stem cells was performed in 2009, when doctors isolated heart tissue from a patient, cultured the tissue in a laboratory, stimulated cell dedifferentiation, and then reinfused the cardiac stem cells directly into the patients heart. A similar study involving 14 patients who underwent cardiac bypass surgery followed by cardiac stem cell transplantation was reported in 2011. More than three months after stem cell transplantation, the patients experienced a slight but detectable improvement in heart function.

Patient-specific induced pluripotent stem cells and dedifferentiated cells are highly valuable in terms of their therapeutic applications because they are unlikely to be rejected by the immune system. However, before induced pluripotent stem cells can be used to treat human diseases, researchers must find a way to introduce the active reprogramming genes without using retroviruses, which can cause diseases such as leukemia in humans. A possible alternative to the use of retroviruses to transport regulatory genes into the nuclei of adult cells is the use of plasmids, which are less tumourigenic than viruses.

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stem cell | Definition, Types, Uses, Research, & Facts ...

Stem cell transplantation, sometimes referred to as bone marrow transplant, is a procedure that replaces unhealthy blood-forming cells with healthy cells. Stem cell transplantation allows doctors to give large doses of chemotherapy or radiation therapy to increase the chance of eliminating blood cancer in the marrow and then restoring normal blood cell production. Researchers continue to improve stem cell transplantation procedures, making them an option for more patients.

The basis for stem cell transplantation is that blood cells (red cells, white cells and platelets) and immune cells (lymphocytes) arise from the stem cells, which are present in marrow, peripheral blood and cord blood. Intense chemotherapy or radiation therapy kills the patient's stem cells. This stops the stem cells from making enough blood and immune cells.

The patient receives high-dose chemotherapy and/or radiation therapy, followed by the stem cell transplant. A donor's stem cells are then transfused into the patient's blood. The transplanted stem cells go from the patient's blood to his or her marrow.

The donor is usually a brother or a sister if one is available and if he or she is a match for the patient. Otherwise, an unrelated person with stem cells that match the patient's tissue type can be used. These matched unrelated donors (MUDs) can be found through stem cell donor banks or registries.

The new cells grow and provide a supply of red cells, white cells (including immune cells) and platelets. The donated stem cells make immune cells that are not totally matched with the patient's cells. (Patients and donors are matched to major tissue types but not minor tissue types.) For this reason, the donor immune cells may recognize the patient's cancer cells' minor tissue types as foreign and kill the cancer cells. This is called "graft versus cancer effect."

If you're a candidate for a stem cell transplant, your doctor will usually recommend one of three types:

A fourth type of stem cell transplantation, syngeneic transplantation, is much less common than the other three. Syngeneic transplantation is rare for the simple reason that it's only used on identical twins. In addition, the donor twin and the recipient twin must have identical genetic makeup and tissue type.

Your doctor considers several factors when deciding whether you're a candidate for stem cell transplantation. For allogeneic stem cell transplantation, your doctor takes into account:

When considering whether you're a candidate for an autologous stem cell transplantation, your doctor takes into account:

Allogeneic stem cell transplant is more successful in younger patients than older patients. About three-quarters of the people who develop a blood cancer are older than 50. In general, older individuals are more likely to:

However, the above factors are generalizations, and there's no specific age cutoff for stem cell transplantation.

Other factors and the response of the underlying disease to initial cancer therapy determine when your doctor considers transplant options. Some patients undergo stem cell transplantation in first remission. For other patients, it's recommended later in the course of treatment for relapsed or refractory disease.

Before you undergo stem cell transplantation, you'll need pretreatment, also called conditioning treatment. You'll be given high-dose chemotherapy or radiation therapy to:

Pretreatment for a reduced-intensity allogeneic stem cell transplant involves lower dosages of chemotherapy drugs or radiation than for a standard allogeneic stem cell transplant.

Donor stem cells are transferred to patients by infusion, a procedure similar to a blood transfusion. Blood is delivered through a catheter a thin flexible tube into a large blood vessel, usually in your chest.

Infusing the stem cells usually takes several hours. You'll be checked frequently for signs of fever, chills, hives, a drop in blood pressure or shortness of breath. You may experience side effects such as headache, nausea, flushing and shortness of breath from the cryopreservative used to freeze the stem cells. If so, you'll be treated and then continue infusion.

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Stem Cell Treatment | Arizona | Stem Cell Rejuvenation Center

An adult stem cell is thought to be an undifferentiated cell, found among differentiated cells in a tissue or organ. The adult stem cell can renew itself and can differentiate to yield some or all of the major specialized cell types of the tissue or organ. The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. Scientists also use the term somatic stem cell instead of adult stem cell, where somatic refers to cells of the body (not the germ cells, sperm or eggs). Unlike embryonic stem cells, which are defined by their origin (cells from the preimplantation-stage embryo), the origin of adult stem cells in some mature tissues is still under investigation.

Research on adult stem cells has generated a great deal of excitement. Scientists have found adult stem cells in many more tissues than they once thought possible. This finding has led researchers and clinicians to ask whether adult stem cells could be used for transplants. In fact, adult hematopoietic, or blood-forming, stem cells from bone marrow have been used in transplants for more than 40 years. Scientists now have evidence that stem cells exist in the brain and the heart, two locations where adult stem cells were not at firstexpected to reside. If the differentiation of adult stem cells can be controlled in the laboratory, these cells may become the basis of transplantation-based therapies.

The history of research on adult stem cells began more than 60 years ago. In the 1950s, researchers discovered that the bone marrow contains at least two kinds of stem cells. One population, called hematopoietic stem cells, forms all the types of blood cells in the body. A second population, called bone marrow stromal stem cells (also called mesenchymal stem cells, or skeletal stem cells by some), were discovered a few years later. These non-hematopoietic stem cells make up a small proportion of the stromal cell population in the bone marrow and can generate bone, cartilage, and fat cells that support the formation of blood and fibrous connective tissue.

In the 1960s, scientists who were studying rats discovered two regions of the brain that contained dividing cells that ultimately become nerve cells. Despite these reports, most scientists believed that the adult brain could not generate new nerve cells. It was not until the 1990s that scientists agreed that the adult brain does contain stem cells that are able to generate the brain's three major cell typesastrocytes and oligodendrocytes, which are non-neuronal cells, and neurons, or nerve cells.

Adult stem cells have been identified in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and testis. They are thought to reside in a specific area of each tissue (called a "stem cell niche"). In many tissues, current evidence suggests that some types of stem cells are pericytes, cells that compose the outermost layer of small blood vessels. Stem cells may remain quiescent (non-dividing) for long periods of time until they are activated by a normal need for more cells to maintain tissues, or by disease or tissue injury.

Typically, there is a very small number of stem cells in each tissue and, once removed from the body, their capacity to divide is limited, making generation of large quantities of stem cells difficult. Scientists in many laboratories are trying to find better ways to grow large quantities of adult stem cells in cell culture and to manipulate them to generate specific cell types so they can be used to treat injury or disease. Some examples of potential treatments include regenerating bone using cells derived from bone marrow stroma, developing insulin-producing cells for type1 diabetes, and repairing damaged heart muscle following a heart attack with cardiac muscle cells.

Scientists often use one or more of the following methods to identify adult stem cells: (1) label the cells in a living tissue with molecular markers and then determine the specialized cell types they generate; (2) remove the cells from a living animal, label them in cell culture, and transplant them back into another animal to determine whether the cells replace (or "repopulate") their tissue of origin.

Importantly, scientists must demonstrate that a single adult stem cell can generate a line of genetically identical cells that then gives rise to all the appropriate differentiated cell types of the tissue. To confirm experimentally that a putative adult stem cell is indeed a stem cell, scientists tend to show either that the cell can give rise to these genetically identical cells in culture, and/or that a purified population of these candidate stem cells can repopulate or reform the tissue after transplant into an animal.

As indicated above, scientists have reported that adult stem cells occur in many tissues and that they enter normal differentiation pathways to form the specialized cell types of the tissue in which they reside.

Normal differentiation pathways of adult stem cells. In a living animal, adult stem cells are available to divide for a long period, when needed, and can give rise to mature cell types that have characteristic shapes and specialized structures and functions of a particular tissue. The following are examples of differentiation pathways of adult stem cells (Figure 2) that have been demonstrated in vitro or in vivo.

Figure 2. Hematopoietic and stromal stem cell differentiation. Click here for larger image. ( 2008 Terese Winslow)

Transdifferentiation. A number of experiments have reported that certain adult stem cell types can differentiate into cell types seen in organs or tissues other than those expected from the cells' predicted lineage (i.e., brain stem cells that differentiate into blood cells or blood-forming cells that differentiate into cardiac muscle cells, and so forth). This reported phenomenon is called transdifferentiation.

Although isolated instances of transdifferentiation have been observed in some vertebrate species, whether this phenomenon actually occurs in humans is under debate by the scientific community. Instead of transdifferentiation, the observed instances may involve fusion of a donor cell with a recipient cell. Another possibility is that transplanted stem cells are secreting factors that encourage the recipient's own stem cells to begin the repair process. Even when transdifferentiation has been detected, only a very small percentage of cells undergo the process.

In a variation of transdifferentiation experiments, scientists have recently demonstrated that certain adult cell types can be "reprogrammed" into other cell types in vivo using a well-controlled process of genetic modification (see Section VI for a discussion of the principles of reprogramming). This strategy may offer a way to reprogram available cells into other cell types that have been lost or damaged due to disease. For example, one recent experiment shows how pancreatic beta cells, the insulin-producing cells that are lost or damaged in diabetes, could possibly be created by reprogramming other pancreatic cells. By "re-starting" expression of three critical beta cell genes in differentiated adult pancreatic exocrine cells, researchers were able to create beta cell-like cells that can secrete insulin. The reprogrammed cells were similar to beta cells in appearance, size, and shape; expressed genes characteristic of beta cells; and were able to partially restore blood sugar regulation in mice whose own beta cells had been chemically destroyed. While not transdifferentiation by definition, this method for reprogramming adult cells may be used as a model for directly reprogramming other adult cell types.

In addition to reprogramming cells to become a specific cell type, it is now possible to reprogram adult somatic cells to become like embryonic stem cells (induced pluripotent stem cells, iPSCs) through the introduction of embryonic genes. Thus, a source of cells can be generated that are specific to the donor, thereby increasing the chance of compatibility if such cells were to be used for tissue regeneration. However, like embryonic stem cells, determination of the methods by which iPSCs can be completely and reproducibly committed to appropriate cell lineages is still under investigation.

Many important questions about adult stem cells remain to be answered. They include:

Previous|IV. What are adult stem cells?|Next

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Stem Cell Basics IV. | stemcells.nih.gov

Pluripotent stem cells are master cells. Theyre able to make cells from all three basic body layers, so they can potentially produce any cell or tissue the body needs to repair itself. This master property is called pluripotency. Like all stem cells, pluripotent stem cells are also able to self-renew, meaning they can perpetually create more copies of themselves.

There are several types of pluripotent stem cells, including embryonic stem cells. At Childrens Hospital Boston, we use the broader term because pluripotent stem cells can come from different sources, and each method creates a cell with slightly different properties.

But all of them are able to differentiate, or mature, into the three primary groups of cells that form a human being:

Right now, its not clear which type or types of pluripotent stem cells will ultimately be used to create cells for treatment, but all of them are valuable for research purposes, and each type has unique lessons to teach scientists. Scientists are just beginning to understand the subtle differences between the different kinds of pluripotent stem cells, and studying all of them offers the greatest chance of success in using them to help patients.

Types of pluripotent stem cells:

All four types of pluripotent stem cells are being actively studied at Childrens.

Induced pluripotent cells (iPS cells):Scientists have discovered ways to take an ordinary cell, such as a skin cell, and reprogram it by introducing several genes that convert it into a pluripotent cell. These genetically reprogrammed cells are known as induced pluripotent cells, or iPS cells. The Stem Cell Program at Childrens Hospital Boston was one of the first three labs to do this in human cells, an accomplishment cited as the Breakthrough of the Year in 2008 by the journal Science.

iPS cells offer great therapeutic potential. Because they come from a patients own cells, they are genetically matched to that patient, so they can eliminate tissue matching and tissue rejection problems that currently hinder successful cell and tissue transplantation. iPS cells are also a valuable research tool for understanding how different diseases develop.

Because iPS cells are derived from skin or other body cells, some people feel that genetic reprogramming is more ethical than deriving embryonic stem cells from embryos or eggs. However, this process must be carefully controlled and tested for safety before its used to create treatments. In animal studies, some of the genes and the viruses used to introduce them have been observed to cause cancer. More research is also needed to make the process of creating iPS cells more efficient.

iPS cells are of great interest at Childrens, and the lab of George Q. Daley, MD, PhD, Director of Stem Cell Transplantation Program, reported creating 10 disease-specific iPS lines, the start of a growing repository of iPS cell lines.

Embryonic stem cells:Scientists use embryonic stem cell as a general term for pluripotent stem cells that are made using embryos or eggs, rather than for cells genetically reprogrammed from the body. There are several types of embryonic stem cells:

1. True embryonic stem cell (ES cells)These are perhaps the best-known type of pluripotent stem cell, made from unused embryos that are donated by couples who have undergone in vitro fertilization (IVF). The IVF process, in which the egg and sperm are brought together in a lab dish, frequently generates more embryos than a couple needs to achieve a pregnancy.

These unused embryos are sometimes frozen for future use, sometimes made available to other couples undergoing fertility treatment, and sometimes simply discarded, but some couples choose to donate them to science. For details on how theyre turned into stem cells, visit our page How do we get pluripotent stem cells?

Pluripotent stem cells made from embryos are generic and arent genetically matched to a particular patient, so are unlikely to be used to create cells for treatment. Instead, they are used to advance our knowledge of how stem cells behave and differentiate.

2. Stem cells made by somatic cell nuclear transfer (ntES cells)The term somatic cell nuclear transfer (SCNT) means, literally, transferring the nucleus (which contains all of a cells genetic instructions) from a somatic cellany cell of the bodyto another cell, in this case an egg cell. This type of pluripotent stem cell, sometimes called an ntES cell, has only been made successfully in lower animals. To make ntES cells in human patients, an egg donor would be needed, as well as a cell from the patient (typically a skin cell).

The process of transferring a different nucleus into the egg reprograms it to a pluripotent state, reactivating the full set of genes for making all the tissues of the body. The egg is then allowed to develop in the lab for several days, and pluripotent stem cells are derived from it. (Read more in How do we get pluripotent stem cells?)

Like iPS cells, ntES cells match the patient genetically. If created successfully in humans, and if proven safe, ntES cells could completely eliminate tissue matching and tissue rejection problems. For this reason, they are actively being researched at Childrens.

3. Stem cells from unfertilized eggs (parthenogenetic embryonic stem cells)Through chemical treatments, unfertilized eggs can be tricked into developing into embryos without being fertilized by sperm, a process called parthenogenesis. The embryos are allowed to develop in the lab for several days, and then pluripotent stem cells can be derived from them (for more, see How do we get pluripotent stem cells?)

If this technique is proven safe, a woman might be able to donate her own eggs to create pluripotent stem cells matching her genetically that in turn could be used to make cells that wouldnt be rejected by her immune system.

Through careful genetic typing, it might also be possible to use pES cells to create treatments for patients beyond the egg donor herself, by creating master banks of cells matched to different tissue types. In 2006, working with mice, Childrens researchers were the first to demonstrate the potential feasibility of this approach. (For details, see Turning pluripotent stem cells into treatment).

Because pES cells can be made more easily and more efficiently than ntES cells, they could potentially be ready for clinical use sooner. However, more needs to be known about their safety. Concerns have been raised that tissues derived from them might not function normally.

Read more about pluripotent stem cells by following these links:

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Pluripotent Stem Cells 101 | Boston Children's Hospital

There are several ways adult stem cells can be isolated, most of which are being actively explored by our researchers.

1) From the body itself:Scientists are discovering that many tissues and organs contain a small number of adult stem cells that help maintain them. Adult stem cells have been found in the brain, bone marrow, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, and other (although not all) organs and tissues. They are thought to live in a specific area of each tissue, where they may remain dormant for years, dividing and creating new cells only when they are activated by tissue injury, disease or anything else that makes the body need more cells.

Adult stem cells can be isolated from the body in different ways, depending on the tissue. Blood stem cells, for example, can be taken from a donors bone marrow, from blood in the umbilical cord when a baby is born, or from a persons circulating blood. Mesenchymal stem cells, which can make bone, cartilage, fat, fibrous connective tissue, and cells that support the formation of blood can also be isolated from bone marrow. Neural stem cells (which form the brains three major cell types) have been isolated from the brain and spinal cord. Research teams at Childrens, headed by leading scientists Stuart Orkin, MD and William Pu, MD, both affiliate members of the Stem Cell Program, recently isolated cardiac stem cells from the heart.

Isolating adult stem cells, however, is just the first step. The cells then need to be grown to large enough numbers to be useful for treatment purposes. The laboratory of Leonard Zon, MD, director of the Stem Cell Program, has developed a technique for boosting numbers of blood stem cells thats now in Phase I clinical testing.

2) From amniotic fluid:Amniotic fluid, which bathes the fetus in the womb, contains fetal cells including mesenchymal stem cells, which are able to make a variety of tissues. Many pregnant women elect to have amniotic fluid drawn to test for chromosome defects, the procedure known as amniocentesis. This fluid is normally discarded after testing, but Childrens Hospital Boston surgeon Dario Fauza, MD, a Principal Investigator at Childrens and an affiliate member of the Stem Cell Program, has been investigating the idea of isolating mesenchymal stem cells and using them to grow new tissues for babies who have birth defects detected while they are still in the womb, such as congenital diaphragmatic hernia. These tissues would match the baby genetically, so would not be rejected by the immune system, and could be implanted either in utero or after the baby is born.

3) From pluripotent stem cells:Because embryonic stem cells and induced pluripotent cells (iPS cells), which are functionally similar, are able to create all types of cells and tissues, scientists at Childrens and elsewhere hope to use them to produce many different kinds of adult stem cells. Laboratories around the world are testing different chemical and mechanical factors that might prod embryonic stem cells or iPS cells into forming a particular kind of adult stem cell. Adult stem cells made in this fashion would potentially match the patient genetically, eliminating both the problem of tissue rejection and the need for toxic therapies to suppress the immune system.

4) From other adult stem cells:A number of research groups have reported that certain kinds of adult stem cells can transform, or differentiate, into apparently unrelated cell types (such as brain stem cells that differentiate into blood cells or blood-forming cells that differentiate into cardiac muscle cells). This phenomenon, called transdifferentiation, has been reported in some animals. However, its still far from clear how versatile adult stem cells really are, whether transdifferentiation can occur in human cells, or whether it could be made to happen reliably in the lab.

More here:
Where Do We Get Adult Stem Cells? | Boston Children's Hospital

Michael Joyce is a multimedia producer at HealthNewsReview.org and tweets as @mlmjoyce

Stem cell clinics are booming. And hurting people.

How can patients protect themselves in a marketplace where the Food & Drug Administration (FDA), Federal Trade Commission (FTC), and state medical boards have been ineffectual?

In this podcast youll hear from George Gibson (a patient left blind after a dubious stem cell intervention), Leigh Turner PhD (a bioethicist whos been following the stem cell marketplace closely), and Drs. Jeanne Loring and Paul Knoepfler two PhD stem cell researchers from California.

There are two websites that most of the people I interviewed for this story recommended as reliable and user-friendly places to go for further information on stem cells:

Although its directed at journalists, our 9 Writing Tips to Combat Stem Cell Hype in Your News Storiesalso will be of interest to most readers of health care news.Weve closely followedcoverage of stem cells for the past several years. Heres just a sampling:

Bioethicist Leigh Turner, who was interviewed for this podcast, has published two papers in the past year that may be of interest. The first was published in the summer of 2016 and was co-authored by Paul Knoepfler. It offers a compelling look into the number and locations of stem cell clinics marketing directly to US consumers.

This summer Turner published a study documenting the use of clinicaltrials.gov by clinics offering unregulated interventions. In this Q&A with Turner, he discusses much of the background leading up to the publication. Its a very interesting read.

Also quite provocative is this very concise call to action penned by Tim Caulfield, Douglass Sipp, and others published just last month. It offers an important perspective on whats needed to keep people from being harmed by unregulated stem cell therapies.

Finally wed like to continue the conversation and would love to hear from you during our upcoming Twitter chat!

You can listen to all our podcasts HERE.

A new study made global headlines last week with the claim that researchers can now

Paul Knoepfler PhD is "disturbed and concerned." Here's why. Knoepfler is a stem cell researcher

If you had been in Salt Lake City last month, savoringyour morningcoffee, and watching this

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PODCAST #33: The Wild West of stem cells - HealthNewsReview.org

By adding theright concoction of ingredients, scientists can reprogram youreverydaysomatic cell intoan inducedpluripotentstemcell(IPSC) that is,aculturedcellthat has the ability todifferentiate into almost any othercelltypein response to specificenvironmentalfactors, similar to an embryonic stem cell. Thisinnovativetechnology allows the study of the molecularmechanismsofearlydevelopmentanddisease,withouttheethical restrictionsassociated withembryonic stem cells.

Not surprisingly, the possibility of utilizing induced pluripotent stem cells in the field of regenerative medicine is of important focus to many scientists. In a recent post, we touched on the potential ability of vitamins A and C to enhance the erasure of epigenetic memory required for cell reprogramming. Because these special types of cells can propagate indefinitely and form any other cell type in the body such as neurons, liver, and heart cells we may be able to replace lost organs, repair tissue, and even generate type O red blood cells, which can be used in transfusions for people with any blood type.

Greatso whats the problem?

Unfortunately, thereare drawbacksto this technology, namely the efficiency of reprogramming.Many IPSCsdo not actually gain completepluripotency. Epigenetic modifications are heavily implicated during the reprogramming process whereby the epigenetic makeup of the cell is completely overhauledto first encourage the expression of pluripotent genes and thenremodelled to encourage the expression of genes associated withthefinalcell typethattheIPSCwillbecome. As the epigenome plays a crucial role inreprogramming,inconsistenciesof pluripotencyacrossIPSClinesmaybedue toepigenetic barriers.

TRIM28: a novel epigenetic barrier

A team of scientists headed by Dr. Miles from The Netherlands Cancer institute recently uncovered a novel epigenetic barrier to the efficient induction of pluripotent stem cell reprogramming. Published in a recent issue of STEM CELLS, the paper highlights the use of a shRNA screen targeting over 670 epigenetic modifiers, revealing the involvement of TRIM28 in the resistance of cells transitioning from somatic to pluripotent state.

TRIM28, or Tripartite motif-containing 28, is involved in mediating transcriptional control by interacting with a certain domain in numerous transcription factors. Previous research shows that it plays a role in cellular differentiation and proliferation, DNA damage repair response, transcriptional regulation, and apoptosis.

By blocking the expression TRIM28 during reprogramming, the group demonstrated increases in the number of cells reaching pluripotency, as well as increased expression of a selection of 143 genes.

Analysis of the list of genes revealed the most statistically significant gene ontology term was unclassified. This result indicates TRIM28 does not regulate a specific pathway during reprogramming, states the authors.

It is known that TRIM28 gene encodes for a protein known to be involved in transcriptional regulation via the recruitment and formation of protein complexes that maintain repressive chromatin. Given this, researchers proposed the gene expression alterations, hence reprogramming differences, were likely to be associated with chromatin modification.

Subsequent tests supported this notion by establishing a proportion of the 143 genes to be located near H3K9me3 a repressive histone H3 modification which has shown to influence the transcription of genes that impedes the IPSC reprogramming process. When TRIM28 expression was blocked, the closer genes are to the H3K9me3 the greater the increase in expression. This suggests the role of TRIM28 in repressing the expression of genes involved in reprogramming via the maintenance of H3K9me3 heterochromatin site.

Whyis this important?

Due to the potential to produce almost anyothertype of cell, thetechnology ofIPSChas sparked excitement in the clinical sciences. The implementation ofIPSCto repair damaged or diseased tissue or to test/develop personalised medicines ison the horizon.By establishing barriers preventing the efficient transition of differentiated cells to pluripotent cells scientist canrefineIPSC generationto make the future clinical use ofIPSCsboth safe and efficient.

Source: Miles, D. C., de Vries, N. A., Gisler, S., Lieftink, C., Akhtar, W., Gogola, E., & Beijersbergen, R. L. (2017). TRIM28 is an Epigenetic Barrier to Induced Pluripotent Stem Cell Reprogramming.STEM CELLS,35(1), 147-157.

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A New Epigenetic Barrier to Induced Pluripotent Stem Cells - WhatIsEpigenetics.com

Hypothalamic Stem Cells

The hypothalamus is the region of the brain that helps to regulate internal conditions like body temperature and blood concentration, but new research shows that it may fail us as we age. The research indicates that as the hypothalamuss stem cells die off, the region actually starts to promote aging, causing mental and physical faculties to decline at a more rapid pace.

In the past, researchers have observed that the hypothalamus becomes inflamed over time. This lead them to posit that the area is connected to aging. Recent research on mice proved that reversing the inflammation in the hypothalamus increases the animals life span and slows physical deterioration. In this latest study, scientists focusedon the stem cells of the hypothalamus. In younger animals, these stem cells divide and replace damaged and dead cells. However, as this research shows, over time the number of stem cells present in the hypothalamus drops. Inold age, they are essentially gone.

The team believed they were on to something, but undertook some practical experiments to see if their ideas were borne out by the evidence. First, they altered mice genetically to ensure theyd be out of stem cells(at a point earlier than would occur naturally). Reducing the stem cells in the mice by around 70 percent meant a life span that was about 8 percent shorter. This accelerated loss of stem cells also caused a loss of coordination, endurance, and memory, as well as behavior that was less youthful, curious, and social. When the team injected stem cells into the hypothalami of middle-aged mice, those mice gained about about 10 percent more mental and physical capabilities compared to mice injected with regular brain cells.

Originally, scientists believed that the stem cell loss could besignificant because it meant the host was unable to repair and replace damaged and dead cells. However, when the hypothalami of middle-aged mice were injected with stem cells, they improved too rapidly for this to be thecorrect mechanism. Instead, the team suspected microRNAs might be at work.

The RNA molecules, called microRNAs, are manufactured and released by stem cells to carry messages to other cells. Practically, based on the messages they carry, microRNAs mayalter the proteins cells produce. The researchers discovered that the stem cells in the hypothalamus produce massive amounts of microRNAs contained in tiny exosomes. In fact, when they injected mice with exosomes packed with microRNA from young hypothalamus stem cells, the effects were almost as effective in slowing signs of mental and physical aging as injections of stem cells were.

Recent research has focused on the role of mitochondria in aging and on the use of induced pluripotent stem (iPS) cells in combatting aging in hematopoietic stem cells. Research from this year has also shown that cannabis-based treatment appears to reverse aging in the brains of mice. Concerning thisresearch, protecting or replacing the stem cells of the hypothalamus or somehow reinforcing or replacing the microRNA effects could slow aging in humans. This could mean testing current drugs such as acarbose (presently used to treat diabetes) to see if they can suppress the hypothalamic inflammation that causes the stem cells to die.

Continue reading here:
Hypothalamic Stem Cells Could Provide New Insights Into Aging - Futurism