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Stem-cell therapy – Wikipedia

This article is about the medical therapy. For the cell type, see Stem cell.

Stem-cell therapy is the use of stem cells to treat or prevent a disease or condition.[1]

Bone marrow transplant is the most widely used stem-cell therapy, but some therapies derived from umbilical cord blood are also in use. Research is underway to develop various sources for stem cells, as well as to apply stem-cell treatments for neurodegenerative diseases and conditions such as diabetes and heart disease, among others.

Stem-cell therapy has become controversial following developments such as the ability of scientists to isolate and culture embryonic stem cells, to create stem cells using somatic cell nuclear transfer and their use of techniques to create induced pluripotent stem cells. This controversy is often related to abortion politics and to human cloning. Additionally, efforts to market treatments based on transplant of stored umbilical cord blood have been controversial.

For over 30 years, bone marrow has been used to treat people with cancer with conditions such as leukaemia and lymphoma; this is the only form of stem-cell therapy that is widely practiced.[2][3][4] During chemotherapy, most growing cells are killed by the cytotoxic agents. These agents, however, cannot discriminate between the leukaemia or neoplastic cells, and the hematopoietic stem cells within the bone marrow. It is this side effect of conventional chemotherapy strategies that the stem-cell transplant attempts to reverse; a donor’s healthy bone marrow reintroduces functional stem cells to replace the cells lost in the host’s body during treatment. The transplanted cells also generate an immune response that helps to kill off the cancer cells; this process can go too far, however, leading to graft vs host disease, the most serious side effect of this treatment.[5]

Another stem-cell therapy called Prochymal, was conditionally approved in Canada in 2012 for the management of acute graft-vs-host disease in children who are unresponsive to steroids.[6] It is an allogenic stem therapy based on mesenchymal stem cells (MSCs) derived from the bone marrow of adult donors. MSCs are purified from the marrow, cultured and packaged, with up to 10,000 doses derived from a single donor. The doses are stored frozen until needed.[7]

The FDA has approved five hematopoietic stem-cell products derived from umbilical cord blood, for the treatment of blood and immunological diseases.[8]

In 2014, the European Medicines Agency recommended approval of limbal stem cells for people with severe limbal stem cell deficiency due to burns in the eye.[9]

Stem cells are being studied for a number of reasons. The molecules and exosomes released from stem cells are also being studied in an effort to make medications.[10] In addition to the functions of the cells themselves, paracrine soluble factors produced by stem cells, known as the stem cell secretome, has been found to be another mechanism by which stem cell-based therapies mediate their effects in degenerative, auto-immune and inflammatory diseases.[11]

Research has been conducted on the effects of stem cells on animal models of brain degeneration, such as in Parkinson’s, Amyotrophic lateral sclerosis, and Alzheimer’s disease.[12][13][14] There have been preliminary studies related to multiple sclerosis.[15][16]

Healthy adult brains contain neural stem cells which divide to maintain general stem-cell numbers, or become progenitor cells. In healthy adult laboratory animals, progenitor cells migrate within the brain and function primarily to maintain neuron populations for olfaction (the sense of smell). Pharmacological activation of endogenous neural stem cells has been reported to induce neuroprotection and behavioral recovery in adult rat models of neurological disorder.[17][18][19]

Stroke and traumatic brain injury lead to cell death, characterized by a loss of neurons and oligodendrocytes within the brain. Clinical and animal studies have been conducted into the use of stem cells in cases of spinal cord injury.[20][21][22]

Stem cells are studied in people with severe heart disease.[23] The work by Bodo-Eckehard Strauer[24] was discredited by identifying hundreds of factual contradictions.[25] Among several clinical trials reporting that adult stem cell therapy is safe and effective, actual evidence of benefit has been reported from only a few studies.[26] Some preliminary clinical trials achieved only modest improvements in heart function following use of bone marrow stem cell therapy.[27][28]

Stem-cell therapy for treatment of myocardial infarction usually makes use of autologous bone marrow stem cells, but other types of adult stem cells may be used, such as adipose-derived stem cells.[29]

Possible mechanisms of recovery include:[12]

In 2013, studies of autologous bone marrow stem cells on ventricular function were found to contain “hundreds” of discrepancies.[30] Critics report that of 48 reports there seemed to be just five underlying trials, and that in many cases whether they were randomized or merely observational accepter-versus-rejecter, was contradictory between reports of the same trial. One pair of reports of identical baseline characteristics and final results, was presented in two publications as, respectively, a 578 patient randomized trial and as a 391 subject observational study. Other reports required (impossible) negative standard deviations in subsets of people, or contained fractional subjects, negative NYHA classes. Overall there were many more people published as having receiving stem cells in trials, than the number of stem cells processed in the hospital’s laboratory during that time. A university investigation, closed in 2012 without reporting, was reopened in July 2013.[31]

In 2014, a meta-analysis on stem cell therapy using bone marrow stem cells for heart disease revealed discrepancies in published clinical trial reports, whereby studies with a higher number of discrepancies showed an increase in effect sizes.[32] Another meta-analysis based on the intra-subject data of 12 randomized trials was unable to find any significant benefits of stem cell therapy on primary endpoints, such as major adverse events or increase in heart function measures, concluding there was no benefit.[33]

The TIME trial, which used a randomized, double blind, placebo-controlled trial design, concluded that “bone marrow mononuclear cells administration did not improve recovery of LV function over 2 years” in people who had a myocardial infarction.[34] Accordingly, the BOOST-2 trial conducted in 10 medical centers in Germany and Norway reported that the trial result “does not support the use of nucleated BMCs in patients with STEMI and moderately reduced LVEF”.[35] Furthermore, the trial also did not meet any other secondary MRI endpoints,[36] leading to a conclusion that intracoronary bone marrow stem cell therapy does not offer a functional or clinical benefit.[37]

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]

Fully mature human red blood cells may be generated ex vivo by hematopoietic stem cells (HSCs), which are precursors of red blood cells. In this process, HSCs are grown together with stromal cells, creating an environment that mimics the conditions of bone marrow, the natural site of red-blood-cell growth. Erythropoietin, a growth factor, is added, coaxing the stem cells to complete terminal differentiation into red blood cells.[38] Further research into this technique should have potential benefits to gene therapy, blood transfusion, and topical medicine.

In 2004, scientists at King’s College London discovered a way to cultivate a complete tooth in mice[39] and were able to grow bioengineered teeth stand-alone in the laboratory. Researchers are confident that the tooth regeneration technology can be used to grow live teeth in people.

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]

Heller has reported success in re-growing cochlea hair cells with the use of embryonic stem cells.[43]

Since 2003, researchers have successfully transplanted corneal stem cells into damaged eyes to restore vision. “Sheets of retinal cells used by the team are harvested from aborted fetuses, which some people find objectionable.” When these sheets are transplanted over the damaged cornea, the stem cells stimulate renewed repair, eventually restore vision.[44] The latest such development was in June 2005, when researchers at the Queen Victoria Hospital of Sussex, England were able to restore the sight of forty people using the same technique. The group, led by Sheraz Daya, was able to successfully use adult stem cells obtained from the patient, a relative, or even a cadaver. Further rounds of trials are ongoing.[45]

People with Type 1 diabetes lose the function of insulin-producing beta cells within the pancreas.[46] In recent experiments, scientists have been able to coax embryonic stem cell to turn into beta cells in the lab. In theory if the beta cell is transplanted successfully, they will be able to replace malfunctioning ones in a diabetic patient.[47]

Use of mesenchymal stem cells (MSCs) derived from adult stem cells is under preliminary research for potential orthopedic applications in bone and muscle trauma, cartilage repair, osteoarthritis, intervertebral disc surgery, rotator cuff surgery, and musculoskeletal disorders, among others.[48] Other areas of orthopedic research for uses of MSCs include tissue engineering and regenerative medicine.[48]

Stem cells can also be used to stimulate the growth of human tissues. In an adult, wounded tissue is most often replaced by scar tissue, which is characterized in the skin by disorganized collagen structure, loss of hair follicles and irregular vascular structure. In the case of wounded fetal tissue, however, wounded tissue is replaced with normal tissue through the activity of stem cells.[49] A possible method for tissue regeneration in adults is to place adult stem cell “seeds” inside a tissue bed “soil” in a wound bed and allow the stem cells to stimulate differentiation in the tissue bed cells. This method elicits a regenerative response more similar to fetal wound-healing than adult scar tissue formation.[49] Researchers are still investigating different aspects of the “soil” tissue that are conducive to regeneration.[49] Because of the general healing capabilities of stem cells, they have gained interest for the treatment of cutaneous wounds, such as in skin cancer.[50]

Culture of human embryonic stem cells in mitotically inactivated porcine ovarian fibroblasts (POF) causes differentiation into germ cells (precursor cells of oocytes and spermatozoa), as evidenced by gene expression analysis.[51]

Human embryonic stem cells have been stimulated to form Spermatozoon-like cells, yet still slightly damaged or malformed.[52] It could potentially treat azoospermia.

In 2012, oogonial stem cells were isolated from adult mouse and human ovaries and demonstrated to be capable of forming mature oocytes.[53] These cells have the potential to treat infertility.

Destruction of the immune system by the HIV is driven by the loss of CD4+ T cells in the peripheral blood and lymphoid tissues. Viral entry into CD4+ cells is mediated by the interaction with a cellular chemokine receptor, the most common of which are CCR5 and CXCR4. Because subsequent viral replication requires cellular gene expression processes, activated CD4+ cells are the primary targets of productive HIV infection.[54] Recently scientists have been investigating an alternative approach to treating HIV-1/AIDS, based on the creation of a disease-resistant immune system through transplantation of autologous, gene-modified (HIV-1-resistant) hematopoietic stem and progenitor cells (GM-HSPC).[55]

Stem cells are thought to mediate repair via five primary mechanisms: 1) providing an anti-inflammatory effect, 2) homing to damaged tissues and recruiting other cells, such as endothelial progenitor cells, that are necessary for tissue growth, 3) supporting tissue remodeling over scar formation, 4) inhibiting apoptosis, and 5) differentiating into bone, cartilage, tendon, and ligament tissue.[56][57]

To further enrich blood supply to the damaged areas, and consequently promote tissue regeneration, platelet-rich plasma could be used in conjunction with stem cell transplantation.[58][59] The efficacy of some stem cell populations may also be affected by the method of delivery; for instance, to regenerate bone, stem cells are often introduced in a scaffold where they produce the minerals necessary for generation of functional bone.[58][59][60][61]

Stem cells have also been shown to have a low immunogenicity due to the relatively low number of MHC molecules found on their surface. In addition, they have been found to secrete chemokines that alter the immune response and promote tolerance of the new tissue. This allows for allogeneic treatments to be performed without a high rejection risk.[62]

The ability to grow up functional adult tissues indefinitely in culture through Directed differentiation creates new opportunities for drug research. Researchers are able to grow up differentiated cell lines and then test new drugs on each cell type to examine possible interactions in vitro before performing in vivo studies. This is critical in the development of drugs for use in veterinary research because of the possibilities of species specific interactions. The hope is that having these cell lines available for research use will reduce the need for research animals used because effects on human tissue in vitro will provide insight not normally known before the animal testing phase.[63]

Stem cells are being explored for use in conservation efforts. Spermatogonial stem cells have been harvested from a rat and placed into a mouse host and fully mature sperm were produced with the ability to produce viable offspring. Currently research is underway to find suitable hosts for the introduction of donor spermatogonial stem cells. If this becomes a viable option for conservationists, sperm can be produced from high genetic quality individuals who die before reaching sexual maturity, preserving a line that would otherwise be lost.[64]

Most stem cells intended for regenerative therapy are generally isolated either from the patient’s bone marrow or from adipose tissue.[59][61] 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.[65][66] 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.[59][61] 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.[67][68] 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.[58]

New sources of mesenchymal stem cells are being researched, including stem cells present in the skin and dermis which are of interest because of the ease at which they can be harvested with minimal risk to the animal.[69] Hematopoetic stem cells have also been discovered to be travelling in the blood stream and possess equal differentiating ability as other mesenchymal stem cells, again with a very non-invasive harvesting technique.[70]

There is widespread controversy over the use of human embryonic stem cells. This controversy primarily targets the techniques used to derive new embryonic stem cell lines, which often requires the destruction of the blastocyst. Opposition to the use of human embryonic stem cells in research is often based on philosophical, moral, or religious objections.[71] There is other stem cell research that does not involve the destruction of a human embryo, and such research involves adult stem cells, amniotic stem cells, and induced pluripotent stem cells.

On 23 January 2009, the US Food and Drug Administration gave clearance to Geron Corporation for the initiation of the first clinical trial of an embryonic stem-cell-based therapy on humans. The trial aimed evaluate the drug GRNOPC1, embryonic stem cell-derived oligodendrocyte progenitor cells, on people with acute spinal cord injury. The trial was discontinued in November 2011 so that the company could focus on therapies in the “current environment of capital scarcity and uncertain economic conditions”.[72] In 2013 biotechnology and regenerative medicine company BioTime (AMEX:BTX) acquired Geron’s stem cell assets in a stock transaction, with the aim of restarting the clinical trial.[73]

Scientists have reported that MSCs when transfused immediately within few hours post thawing may show reduced function or show decreased efficacy in treating diseases as compared to those MSCs which are in log phase of cell growth(fresh), so cryopreserved MSCs should be brought back into log phase of cell growth in invitro culture before these are administered for clinical trials or experimental therapies, re-culturing of MSCs will help in recovering from the shock the cells get during freezing and thawing. Various clinical trials on MSCs have failed which used cryopreserved product immediately post thaw as compared to those clinical trials which used fresh MSCs.[74]

Research has been conducted on horses, dogs, and cats can benefit the development of stem cell treatments in veterinary medicine and can target a wide range of injuries and diseases such as myocardial infarction, stroke, tendon and ligament damage, osteoarthritis, osteochondrosis and muscular dystrophy both in large animals, as well as humans.[75][76][77][78] While investigation of cell-based therapeutics generally reflects human medical needs, the high degree of frequency and severity of certain injuries in racehorses has put veterinary medicine at the forefront of this novel regenerative approach.[79] Companion animals can serve as clinically relevant models that closely mimic human disease.[80][81]

Veterinary applications of stem cell therapy as a means of tissue regeneration have been largely shaped by research that began with the use of adult-derived mesenchymal stem cells to treat animals with injuries or defects affecting bone, cartilage, ligaments and/or tendons.[82][65][83] There are two main categories of stem cells used for treatments: allogeneic stem cells derived from a genetically different donor within the same species[61][84] and autologous mesenchymal stem cells, derived from the patient prior to use in various treatments.[58] A third category, xenogenic stem cells, or stem cells derived from different species, are used primarily for research purposes, especially for human treatments.[63]

Bone has a unique and well documented natural healing process that normally is sufficient to repair fractures and other common injuries. Misaligned breaks due to severe trauma, as well as treatments like tumor resections of bone cancer, are prone to improper healing if left to the natural process alone. Scaffolds composed of natural and artificial components are seeded with mesenchymal stem cells and placed in the defect. Within four weeks of placing the scaffold, newly formed bone begins to integrate with the old bone and within 32 weeks, full union is achieved.[85] Further studies are necessary to fully characterize the use of cell-based therapeutics for treatment of bone fractures.

Stem cells have been used to treat degenerative bone diseases. The normally recommended treatment for dogs that have LeggCalvePerthes 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.[85]

Autologous stem cell-based treatments for ligament injury, tendon injury, osteoarthritis, osteochondrosis, and sub-chondral bone cysts have been commercially available to practicing veterinarians to treat horses since 2003 in the United States and since 2006 in the United Kingdom. Autologous stem cell based treatments for tendon injury, ligament injury, and osteoarthritis in dogs have been available to veterinarians in the United States since 2005. Over 3000 privately owned horses and dogs have been treated with autologous adipose-derived stem cells. The efficacy of these treatments has been shown in double-blind clinical trials for dogs with osteoarthritis of the hip and elbow and horses with tendon damage.[86][87]

Race horses are especially prone to injuries of the tendon and ligaments. Conventional therapies are very unsuccessful in returning the horse to full functioning potential. Natural healing, guided by the conventional treatments, leads to the formation of fibrous scar tissue that reduces flexibility and full joint movement. Traditional treatments prevented a large number of horses from returning to full activity and also have a high incidence of re-injury due to the stiff nature of the scarred tendon. Introduction of both bone marrow and adipose derived stem cells, along with natural mechanical stimulus promoted the regeneration of tendon tissue. The natural movement promoted the alignment of the new fibers and tendocytes with the natural alignment found in uninjured tendons. Stem cell treatment not only allowed more horses to return to full duty and also greatly reduced the re-injury rate over a three-year period.[62]

The use of embryonic stem cells has also been applied to tendon repair. The embryonic stem cells were shown to have a better survival rate in the tendon as well as better migrating capabilities to reach all areas of damaged tendon. The overall repair quality was also higher, with better tendon architecture and collagen formed. There was also no tumor formation seen during the three-month experimental period. Long-term studies need to be carried out to examine the long-term efficacy and risks associated with the use of embryonic stem cells.[62] Similar results have been found in small animals.[62]

Osteoarthritis is the main cause of joint pain both in animals and humans. Horses and dogs are most frequently affected by arthritis. Natural cartilage regeneration is very limited. Different types of mesenchymal stem cells and other additives are still being researched to find the best type of cell and method for long-term treatment.[62]

Adipose-derived mesenchymal cells are currently the most often used for stem cell treatment of osteoarthritis because of the non-invasive harvesting. 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.[88]

Stem cells have successfully been used to ameliorate healing in the heart after myocardial infarction in dogs. Adipose and bone marrow derived stem cells were removed and induced to a cardiac cell fate before being injected into the heart. The heart was found to have improved contractility and a reduction in the damaged area four weeks after the stem cells were applied.[89]

A different trial is underway for a patch made of a porous substance onto which the stem cells are “seeded” in order to induce tissue regeneration in heart defects. Tissue was regenerated and the patch was well incorporated into the heart tissue. This is thought to be due, in part, to improved angiogenesis and reduction of inflammation. Although cardiomyocytes were produced from the mesenchymal stem cells, they did not appear to be contractile. Other treatments that induced a cardiac fate in the cells before transplanting had greater success at creating contractile heart tissue.[90]

Spinal cord injuries are one of the most common traumas brought into veterinary hospitals.[85] Spinal injuries occur in two ways after the trauma: the primary mechanical damage, and in secondary processes, like inflammation and scar formation, in the days following the trauma. These cells involved in the secondary damage response secrete factors that promote scar formation and inhibit cellular regeneration. Mesenchymal stem cells that are induced to a neural cell fate are loaded onto a porous scaffold and are then implanted at the site of injury. The cells and scaffold secrete factors that counteract those secreted by scar forming cells and promote neural regeneration. Eight weeks later, dogs treated with stem cells showed immense improvement over those treated with conventional therapies. Dogs treated with stem cells were able to occasionally support their own weight, which has not been seen in dogs undergoing conventional therapies.[91][92][93]

Treatments are also in clinical trials to repair and regenerate peripheral nerves. Peripheral nerves are more likely to be damaged, but the effects of the damage are not as widespread as seen in injuries to the spinal cord. Treatments are currently in clinical trials to repair severed nerves, with early success. Stem cells induced to a neural fate injected in to a severed nerve. Within four weeks, regeneration of previously damaged stem cells and completely formed nerve bundles were observed.[69]

Stem cells are also in clinical phases for treatment in ophthalmology. Hematopoietic stem cells have been used to treat corneal ulcers of different origin of several horses. These ulcers were resistant to conventional treatments available, but quickly responded positively to the stem cell treatment. Stem cells were also able to restore sight in one eye of a horse with retinal detachment, allowing the horse to return to daily activities.[70]

In the late 1990s and early 2000s, there was an initial wave of companies and clinics offering stem cell therapy, while not substantiating health claims or having regulatory approval.[94] By 2012, a second wave of companies and clinics had emerged, usually located in developing countries where medicine is less regulated and offering stem cell therapies on a medical tourism model.[95][96] Like the first wave companies and clinics, they made similar strong, but unsubstantiated, claims, mainly by clinics in the United States, Mexico, Thailand, India, and South Africa.[95][96] In 2018, the FDA sent a warning letter to StemGenex Biologic Laboratories in San Diego, which marketed a service in which it took body fat from people, processed it into mixtures it said contained various forms of stem cells, and administered it back to the person by inhalation, intravenously, or infusion into their spinal cords; the company said the treatment was useful for many chronic and life-threatening conditions.[97] In 2018, the US Federal Trade Commission found health centers and an individual physician making unsubstantiated claims for stem cell therapies, and forced refunds of some $500,000.[98]

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Stem-cell therapy – Wikipedia

Stem cells: What they are and what they do – Mayo Clinic

Stem cells: What they are and what they do

Stem cells and derived products offer great promise for new medical treatments. Learn about stem cell types, current and possible uses, ethical issues, and the state of research and practice.

You’ve heard about stem cells in the news, and perhaps you’ve wondered if they might help you or a loved one with a serious disease. You may wonder what stem cells are, how they’re being used to treat disease and injury, and why they’re the subject of such vigorous debate.

Here are some answers to frequently asked questions about stem cells.

Stem cells are the body’s raw materials cells from which all other cells with specialized functions are generated. Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells.

These daughter cells either become new stem cells (self-renewal) or become specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells. No other cell in the body has the natural ability to generate new cell types.

Researchers and doctors hope stem cell studies can help to:

Generate healthy cells to replace diseased cells (regenerative medicine). Stem cells can be guided into becoming specific cells that can be used to regenerate and repair diseased or damaged tissues in people.

People who might benefit from stem cell therapies include those with spinal cord injuries, type 1 diabetes, Parkinson’s disease, amyotrophic lateral sclerosis, Alzheimer’s disease, heart disease, stroke, burns, cancer and osteoarthritis.

Stem cells may have the potential to be grown to become new tissue for use in transplant and regenerative medicine. Researchers continue to advance the knowledge on stem cells and their applications in transplant and regenerative medicine.

Test new drugs for safety and effectiveness. Before using investigational drugs in people, researchers can use some types of stem cells to test the drugs for safety and quality. This type of testing will most likely first have a direct impact on drug development first for cardiac toxicity testing.

New areas of study include the effectiveness of using human stem cells that have been programmed into tissue-specific cells to test new drugs. For the testing of new drugs to be accurate, the cells must be programmed to acquire properties of the type of cells targeted by the drug. Techniques to program cells into specific cells continue to be studied.

For instance, nerve cells could be generated to test a new drug for a nerve disease. Tests could show whether the new drug had any effect on the cells and whether the cells were harmed.

Researchers have discovered several sources of stem cells:

Embryonic stem cells. These stem cells come from embryos that are three to five days old. At this stage, an embryo is called a blastocyst and has about 150 cells.

These are pluripotent (ploo-RIP-uh-tunt) stem cells, meaning they can divide into more stem cells or can become any type of cell in the body. This versatility allows embryonic stem cells to be used to regenerate or repair diseased tissue and organs.

Adult stem cells. These stem cells are found in small numbers in most adult tissues, such as bone marrow or fat. Compared with embryonic stem cells, adult stem cells have a more limited ability to give rise to various cells of the body.

Until recently, researchers thought adult stem cells could create only similar types of cells. For instance, researchers thought that stem cells residing in the bone marrow could give rise only to blood cells.

However, emerging evidence suggests that adult stem cells may be able to create various types of cells. For instance, bone marrow stem cells may be able to create bone or heart muscle cells.

This research has led to early-stage clinical trials to test usefulness and safety in people. For example, adult stem cells are currently being tested in people with neurological or heart disease.

Adult cells altered to have properties of embryonic stem cells (induced pluripotent stem cells). Scientists have successfully transformed regular adult cells into stem cells using genetic reprogramming. By altering the genes in the adult cells, researchers can reprogram the cells to act similarly to embryonic stem cells.

This new technique may allow researchers to use reprogrammed cells instead of embryonic stem cells and prevent immune system rejection of the new stem cells. However, scientists don’t yet know whether using altered adult cells will cause adverse effects in humans.

Researchers have been able to take regular connective tissue cells and reprogram them to become functional heart cells. In studies, animals with heart failure that were injected with new heart cells experienced improved heart function and survival time.

Perinatal stem cells. Researchers have discovered stem cells in amniotic fluid as well as umbilical cord blood. These stem cells also have the ability to change into specialized cells.

Amniotic fluid fills the sac that surrounds and protects a developing fetus in the uterus. Researchers have identified stem cells in samples of amniotic fluid drawn from pregnant women to test for abnormalities a procedure called amniocentesis.

More study of amniotic fluid stem cells is needed to understand their potential.

Embryonic stem cells are obtained from early-stage embryos a group of cells that forms when a woman’s egg is fertilized with a man’s sperm in an in vitro fertilization clinic. Because human embryonic stem cells are extracted from human embryos, several questions and issues have been raised about the ethics of embryonic stem cell research.

The National Institutes of Health created guidelines for human stem cell research in 2009. The guidelines define embryonic stem cells and how they may be used in research, and include recommendations for the donation of embryonic stem cells. Also, the guidelines state embryonic stem cells from embryos created by in vitro fertilization can be used only when the embryo is no longer needed.

The embryos being used in embryonic stem cell research come from eggs that were fertilized at in vitro fertilization clinics but never implanted in a woman’s uterus. The stem cells are donated with informed consent from donors. The stem cells can live and grow in special solutions in test tubes or petri dishes in laboratories.

Although research into adult stem cells is promising, adult stem cells may not be as versatile and durable as are embryonic stem cells. Adult stem cells may not be able to be manipulated to produce all cell types, which limits how adult stem cells can be used to treat diseases.

Adult stem cells also are more likely to contain abnormalities due to environmental hazards, such as toxins, or from errors acquired by the cells during replication. However, researchers have found that adult stem cells are more adaptable than was first thought.

A stem cell line is a group of cells that all descend from a single original stem cell and are grown in a lab. Cells in a stem cell line keep growing but don’t differentiate into specialized cells. Ideally, they remain free of genetic defects and continue to create more stem cells. Clusters of cells can be taken from a stem cell line and frozen for storage or shared with other researchers.

Stem cell therapy, also known as regenerative medicine, promotes the repair response of diseased, dysfunctional or injured tissue using stem cells or their derivatives. It is the next chapter in organ transplantation and uses cells instead of donor organs, which are limited in supply.

Researchers grow stem cells in a lab. These stem cells are manipulated to specialize into specific types of cells, such as heart muscle cells, blood cells or nerve cells.

The specialized cells can then be implanted into a person. For example, if the person has heart disease, the cells could be injected into the heart muscle. The healthy transplanted heart muscle cells could then contribute to repairing defective heart muscle.

Researchers have already shown that adult bone marrow cells guided to become heart-like cells can repair heart tissue in people, and more research is ongoing.

Yes. Doctors have performed stem cell transplants, also known as bone marrow transplants. In stem cell transplants, stem cells replace cells damaged by chemotherapy or disease or serve as a way for the donor’s immune system to fight some types of cancer and blood-related diseases, such as leukemia, lymphoma, neuroblastoma and multiple myeloma. These transplants use adult stem cells or umbilical cord blood.

Researchers are testing adult stem cells to treat other conditions, including a number of degenerative diseases such as heart failure.

For embryonic stem cells to be useful in people, researchers must be certain that the stem cells will differentiate into the specific cell types desired.

Researchers have discovered ways to direct stem cells to become specific types of cells, such as directing embryonic stem cells to become heart cells. Research is ongoing in this area.

Embryonic stem cells can also grow irregularly or specialize in different cell types spontaneously. Researchers are studying how to control the growth and differentiation of embryonic stem cells.

Embryonic stem cells might also trigger an immune response in which the recipient’s body attacks the stem cells as foreign invaders, or the stem cells might simply fail to function normally, with unknown consequences. Researchers continue to study how to avoid these possible complications.

Therapeutic cloning, also called somatic cell nuclear transfer, is a technique to create versatile stem cells independent of fertilized eggs. In this technique, the nucleus, which contains the genetic material, is removed from an unfertilized egg. The nucleus is also removed from the cell of a donor.

This donor nucleus is then injected into the egg, replacing the nucleus that was removed, in a process called nuclear transfer. The egg is allowed to divide and soon forms a blastocyst. This process creates a line of stem cells that is genetically identical to the donor’s cells in essence, a clone.

Some researchers believe that stem cells derived from therapeutic cloning may offer benefits over those from fertilized eggs because cloned cells are less likely to be rejected once transplanted back into the donor and may allow researchers to see exactly how a disease develops.

No. Researchers haven’t been able to successfully perform therapeutic cloning with humans despite success in a number of other species.

However, in recent studies, researchers have created human pluripotent stem cells by modifying the therapeutic cloning process. Researchers continue to study the potential of therapeutic cloning in people.

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Stem cells: What they are and what they do – Mayo Clinic

Is Stem Cell Therapy for Arthritis Safe and Effective?

People considering stem cell treatment for arthritis want to know Is it safe? and Is it effective?

Most stem cell therapy using adult stem cells is considered safe because the stem cells are collected from the patient, minimizing the risk of an unwanted reaction. The most common side effects are temporary swelling and pain.3

While most stem cell therapy for arthritis is considered safe, it does carry the same risks as any other medical procedure, such as a small risk of infection. Risk may be increased if:

See What Are Stem Cells?

Some research suggests stem cell therapy engaging in these kinds of practices may elevate the risk of tumors.4

As with most regenerative medicine treatments, research is ongoing, and FDA regulations are relatively new and subject to change.

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Whether or not stem cells therapy is effective in treating osteoarthritis is a controversial subject among medical professionals, and research in the area is ongoing.

See Osteoarthritis Treatment

How researchers think stem cell therapy worksResearchers theorize5 that when applied to an arthritic joint, stem cells might:

See Osteoarthritis Symptoms and Signs

It may be none, one, two, or all three processes at are work.

Proponents vs criticsLike many relatively new treatments, stem cell therapy has proponents and critics.

Critics emphasize that there have been no large-scale, prospective, double-blind research studiesthe kind of clinical studies that medical professionals consider the gold standardto support stem cell therapy for arthritis.

Factors that affect stem cell therapy researchAnother challenge associated with current stem cell research is that there is no standard stem cell therapy for arthritis treatment. So the stem cell therapy in one study is not necessarily the same as the stem cell therapy in another study.

Differences can include:

These differences are further complicated by more unknowns. For example, how many stem cells are needed for a particular treatment? And how do we determine if a patients own stem cells are competent enough to aid in healing?

Many physicians combine the use of stem cells with platelet rich plasma, or PRP.

See Platelet-Rich Plasma (PRP) Therapy for Arthritis

PRP is derived from a sample of the patients blood. In the body, platelets secrete substances called growth factors and other proteins that regulate cell division, stimulate tissue regeneration, and promote healing. Like stem cell therapy, PRP therapy is sometimes used alone with the hopes of healing an arthritic joint.

See PRP Injection Preparation and Composition

Physicians who use PRP and stem cells together think that the PRP can help maximize the healing effects of stem cells.7,8 Research in this area is ongoing.

See Platelet-Rich Plasma Injection Procedure

Stem cell therapy can vary depending on the doctor performing it. People considering stem cell therapy for an arthritic knee or other joint are advised to ask their doctors questions, including:

Both doctors and patients can benefit from having a frank conversation and setting reasonable expectations.

See Arthritis Treatment Specialists

Complete Listing of References

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Is Stem Cell Therapy for Arthritis Safe and Effective?

Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More

Ripple vs SWIFT: The War Begins
While most criticisms of XRP do nothing to curb my bullish Ripple price forecast, there is one obstacle that nags at my conscience. Its name is SWIFT.

The Society for Worldwide Interbank Financial Telecommunication (SWIFT) is the king of international payments.

It coordinates wire transfers across 11,000 banks in more than 200 countries and territories, meaning that in order for XRP prices to ascend to $10.00, Ripple needs to launch a successful coup. That is, and always has been, an unwritten part of Ripple’s story.

We’ve seen a lot of progress on that score. In the last three years, Ripple wooed more than 100 financial firms onto its.

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Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More

Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More

Cryptocurrency News
On the whole, cryptocurrency prices are down from our previous report on cryptos, with the market slipping on news of an exchange being hacked and a report about Bitcoin manipulation.

However, there have been two bright spots: 1) an official from the U.S. Securities and Exchange Commission (SEC) said that Ethereum is not a security, and 2) Coinbase is expanding its selection of tokens.

Let’s start with the good news.
SEC Says ETH Is Not a Security
Investors have some reason to cheer this week. A high-ranking SEC official told attendees of the Yahoo! All Markets Summit: Crypto that Ethereum and Bitcoin are not.

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Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More

Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto

Cryptocurrency News
This was a bloody week for cryptocurrencies. Everything was covered in red, from Ethereum (ETH) on down to the Basic Attention Token (BAT).

Some investors claim it was inevitable. Others say that price manipulation is to blame.

We think the answers are more complicated than either side has to offer, because our research reveals deep contradictions between the price of cryptos and the underlying development of blockchain projects.

For instance, a leading venture capital (VC) firm launched a $300.0-million crypto investment fund, yet liquidity continues to dry up in crypto markets.

Another example is the U.S. Securities and Exchange Commission’s.

The post Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto appeared first on Profit Confidential.

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Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto

Cryptocurrency News: Looking Past the Bithumb Crypto Hack

Another Crypto Hack Derails Recovery
Since our last report, hackers broke into yet another cryptocurrency exchange. This time the target was Bithumb, a Korean exchange known for high-flying prices and ultra-active traders.

While the hackers made off with approximately $31.5 million in funds, the exchange is working with relevant authorities to return the stolen tokens to their respective owners. In the event that some is still missing, the exchange will cover the losses. (Source: “Bithumb Working With Other Crypto Exchanges to Recover Hacked Funds,”.

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Cryptocurrency News: Looking Past the Bithumb Crypto Hack

Cryptocurrency News: What You Need to Know This Week

Cryptocurrency News
Cryptocurrencies traded sideways since our last report on cryptos. However, I noticed something interesting when playing around with Yahoo! Finance’s cryptocurrency screener: There are profitable pockets in this market.

Incidentally, Yahoo’s screener is far superior to the one on CoinMarketCap, so if you’re looking to compare digital assets, I highly recommend it.

But let’s get back to my epiphany.

In the last month, at one point or another, most crypto assets on our favorites list saw double-digit increases. It’s true that each upswing was followed by a hard crash, but investors who rode the trend would have made a.

The post Cryptocurrency News: What You Need to Know This Week appeared first on Profit Confidential.

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Cryptocurrency News: What You Need to Know This Week

Cryptocurrency News: XRP Validators, Malta, and Practical Tokens

Cryptocurrency News & Market Summary
Investors finally saw some light at the end of the tunnel last week, with cryptos soaring across the board. No one quite knows what kicked off the rally—as it could have been any of the stories we discuss below—but the net result was positive.

Of course, prices won’t stay on this rocket ride forever. I expect to see a resurgence of volatility in short order, because the market is moving as a single unit. Everything is rising in tandem.

This tells me that investors are simply “buying the dip” rather than identifying which cryptos have enough real-world value to outlive the crash.

So if you want to know when.

The post Cryptocurrency News: XRP Validators, Malta, and Practical Tokens appeared first on Profit Confidential.

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Cryptocurrency News: XRP Validators, Malta, and Practical Tokens

Cryptocurrency News: New Exchanges Could Boost Crypto Liquidity

Cryptocurrency News
Even though the cryptocurrency news was upbeat in recent days, the market tumbled after the U.S. Securities and Exchange Commission (SEC) rejected calls for a Bitcoin (BTC) exchange-traded fund (ETF).

That news came as a blow to investors, many of whom believe the ETF would open the cryptocurrency industry up to pension funds and other institutional investors. This would create a massive tailwind for cryptos, they say.

So it only follows that a rejection of the Bitcoin ETF should send cryptos tumbling, correct? Well, maybe you can follow that logic. To me, it seems like a dramatic overreaction.

I understand that legitimizing cryptos is important. But.

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Cryptocurrency News: New Exchanges Could Boost Crypto Liquidity

Cryptocurrency News: Bitcoin ETF Rejection, AMD Microchip Sales, and Hedge Funds

Cryptocurrency News
Although cryptocurrency prices were heating up last week (Bitcoin, especially), regulators poured cold water on the rally by rejecting calls for a Bitcoin exchange-traded fund (ETF). This is the second time that the proposal fell on deaf ears. (More on that below.)

Crypto mining ran into similar trouble, as you can see from Advanced Micro Devices, Inc.‘s (NASDAQ:AMD) most recent quarterly earnings. However, it wasn’t all bad news. Investors should, for instance, be cheering the fact that hedge funds are ramping up their involvement in cryptocurrency markets.

Without further ado, here are those stories in greater detail.
ETF Rejection.

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Cryptocurrency News: Bitcoin ETF Rejection, AMD Microchip Sales, and Hedge Funds

Bitcoin Rise: Is the Recent Bitcoin Price Surge a Sign of Things to Come or Another Misdirection?

What You Need to Know About the Bitcoin Price Rise
It wasn’t that long ago that Bitcoin (BTC) dominated headlines for its massive growth, with many cryptocurrency millionaires being made. The Bitcoin price surged ever upward and many people thought the gravy train would never stop running—until it did.

Prices crashed, investors abandoned the space, and lots of people lost money. Cut to today and we’re seeing another big Bitcoin price surge; is this time any different?

I’m of a mind that investors ought to think twice before jumping back in on Bitcoin.

Bitcoin made waves when it once again crested above $5,000. Considering that it started 2019 around $3,700,.

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Bitcoin Rise: Is the Recent Bitcoin Price Surge a Sign of Things to Come or Another Misdirection?

Cryptocurrency News: Vitalik Buterin Doesn’t Care About Bitcoin ETFs

Cryptocurrency News
While headline numbers look devastating this week, investors might take some solace in knowing that cryptocurrencies found their bottom at roughly $189.8 billion in market cap—that was the low point. Since then, investors put more than $20.0 billion back into the market.

During the rout, Ethereum broke below $300.00 and XRP fell below $0.30, marking yearly lows for both tokens. The same was true down the list of the top 100 biggest cryptos.

Altcoins took the brunt of the hit. BTC Dominance, which reveals how tightly investment is concentrated in Bitcoin, rose from 42.62% to 53.27% in just one month, showing that investors either fled altcoins at higher.

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Cryptocurrency News: Vitalik Buterin Doesn’t Care About Bitcoin ETFs

Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More

Ripple vs SWIFT: The War Begins
While most criticisms of XRP do nothing to curb my bullish Ripple price forecast, there is one obstacle that nags at my conscience. Its name is SWIFT.

The Society for Worldwide Interbank Financial Telecommunication (SWIFT) is the king of international payments.

It coordinates wire transfers across 11,000 banks in more than 200 countries and territories, meaning that in order for XRP prices to ascend to $10.00, Ripple needs to launch a successful coup. That is, and always has been, an unwritten part of Ripple’s story.

We’ve seen a lot of progress on that score. In the last three years, Ripple wooed more than 100 financial firms onto its.

The post Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More appeared first on Profit Confidential.

See the rest here:

Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More

Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More

Cryptocurrency News
On the whole, cryptocurrency prices are down from our previous report on cryptos, with the market slipping on news of an exchange being hacked and a report about Bitcoin manipulation.

However, there have been two bright spots: 1) an official from the U.S. Securities and Exchange Commission (SEC) said that Ethereum is not a security, and 2) Coinbase is expanding its selection of tokens.

Let’s start with the good news.
SEC Says ETH Is Not a Security
Investors have some reason to cheer this week. A high-ranking SEC official told attendees of the Yahoo! All Markets Summit: Crypto that Ethereum and Bitcoin are not.

The post Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More appeared first on Profit Confidential.

Go here to see the original:

Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More

Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto

Cryptocurrency News
This was a bloody week for cryptocurrencies. Everything was covered in red, from Ethereum (ETH) on down to the Basic Attention Token (BAT).

Some investors claim it was inevitable. Others say that price manipulation is to blame.

We think the answers are more complicated than either side has to offer, because our research reveals deep contradictions between the price of cryptos and the underlying development of blockchain projects.

For instance, a leading venture capital (VC) firm launched a $300.0-million crypto investment fund, yet liquidity continues to dry up in crypto markets.

Another example is the U.S. Securities and Exchange Commission’s.

The post Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto appeared first on Profit Confidential.

Continue reading here:

Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto

Cryptocurrency News: Looking Past the Bithumb Crypto Hack

Another Crypto Hack Derails Recovery
Since our last report, hackers broke into yet another cryptocurrency exchange. This time the target was Bithumb, a Korean exchange known for high-flying prices and ultra-active traders.

While the hackers made off with approximately $31.5 million in funds, the exchange is working with relevant authorities to return the stolen tokens to their respective owners. In the event that some is still missing, the exchange will cover the losses. (Source: “Bithumb Working With Other Crypto Exchanges to Recover Hacked Funds,”.

The post Cryptocurrency News: Looking Past the Bithumb Crypto Hack appeared first on Profit Confidential.

Continued here:

Cryptocurrency News: Looking Past the Bithumb Crypto Hack

Cryptocurrency News: What You Need to Know This Week

Cryptocurrency News
Cryptocurrencies traded sideways since our last report on cryptos. However, I noticed something interesting when playing around with Yahoo! Finance’s cryptocurrency screener: There are profitable pockets in this market.

Incidentally, Yahoo’s screener is far superior to the one on CoinMarketCap, so if you’re looking to compare digital assets, I highly recommend it.

But let’s get back to my epiphany.

In the last month, at one point or another, most crypto assets on our favorites list saw double-digit increases. It’s true that each upswing was followed by a hard crash, but investors who rode the trend would have made a.

The post Cryptocurrency News: What You Need to Know This Week appeared first on Profit Confidential.

Read the original:

Cryptocurrency News: What You Need to Know This Week

Cryptocurrency News: XRP Validators, Malta, and Practical Tokens

Cryptocurrency News & Market Summary
Investors finally saw some light at the end of the tunnel last week, with cryptos soaring across the board. No one quite knows what kicked off the rally—as it could have been any of the stories we discuss below—but the net result was positive.

Of course, prices won’t stay on this rocket ride forever. I expect to see a resurgence of volatility in short order, because the market is moving as a single unit. Everything is rising in tandem.

This tells me that investors are simply “buying the dip” rather than identifying which cryptos have enough real-world value to outlive the crash.

So if you want to know when.

The post Cryptocurrency News: XRP Validators, Malta, and Practical Tokens appeared first on Profit Confidential.

Go here to read the rest:

Cryptocurrency News: XRP Validators, Malta, and Practical Tokens


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