F.G.B.

Integrative ActivityStem Cells

Roy Mauricio Castillo Beltrán436

Stem CellsINTRODUCTIONStem Cells are unspecialized cells thatgive rise to one or more types of specializedcells.

What are Stem Cells?

Stem cells are a class of undifferentiated cells that are able to differentiate into specialized cell types. Commonly, stem cells come from two main sources:

•Embryos formed during the blastocyst phase of embryological development (embryonic stem cells) and•Adult tissue (adult stem cells).

Both types are generally characterized by their potency, or potential to differentiate into different cell types (such as skin, muscle, bone, etc.).

Stem Cells Timeline

Discoveries

Stem Cells TimelineDiscoveries1860 - 1920"Stem cells" inferred from analysis of embryo development and microscopy of bone marrow (Germany)

1948 - 58Stem cell mechanisms deduced for sperm development and intestinal epithelium replacement (Canada)

1956First bone marrow transplants performed in human patients (USA)

1958Nuclei from adult frog cells reprogrammed to full embryonic potential after transfer into frog eggs (UK)

1959Experiments in mice prove the existence of resident blood stem cells in marrow (England)

Stem Cells TimelineDiscoveries1961The existence and properties of transplantable stem cells in mouse bone marrow are established and the first colony methodology for counting them is introduced. This discovery set the stage for all current research on adult and embryonic stem cells (Canada)

1968First allogeneic human marrow transplants achieved avoiding lethal rejection reactions (USA)

1969First application of cell separation technology to dissect marrow stem cell hierarchy (Canada)

1961The existence and properties of transplantable stem cells in mouse bone marrow are established and the first colony methodology for counting them is introduced. This discovery set the stage for all current research on adult and embryonic stem cells (Canada)

1968First allogeneic human marrow transplants achieved avoiding lethal rejection reactions (USA)

1969First application of cell separation technology to dissect marrow stem cell hierarchy (Canada)

Stem Cells TimelineDiscoveries1974Mouse embryonic cancer cells are shown to participate in the development of normal tissues as well as teratomas (UK, USA)

1978Transplantable stem cells are discovered in human cord blood (USA)

1981Embryonic stem cells are first derived from the inner cell mass of mouse blastocysts (UK, USA)

1982Marrow stem cells measured by regenerative capacity in vivo are shown to be distinct from progenitors measured by colony methods (Australia, USA)

1984Blood stem cells measured by colony formation in vivo are first extensively purified (Holland)

1982 - 1986First methodology developed for targeted genetic modification in embryonic stem cells (UK, USA)

1990Mouse marrow regenerating stem cells are first completely separated from in vivo colony-forming cells (USA)

1992Neural stem cells identified in the adult human brain (Canada)

1993Pluripotency of embryonic stem cells is proven through the generation of entirely embryonic stem cell-derived mice (Canada)

1994First separation of cancer stem cells from the majority of cells in a cancer (Canada)Patients with damaged corneas are successfully treated with corneal stem cells (Taiwan)

1995First derivation of primate embryonic stem cell lines (USA)

1996First cloning of a mammal: Dolly the sheep is born (Scotland)

1998First human embryonic stem cell line derived (USA)

2000Retinal stem cells identified in mice (Canada)

2001First collaborative stem cell research network - the Stem Cell Network - is formed (Canada)Dermal stem cells identified in adult skin tissue (Canada)

2002First complete purification from mice of multipotent marrow stem cells capable as single injected cells of extended marrow regeneration in vivo (Canada)The International Society for Stem Cell Research is formed.Creation of the International Stem Cell Forum (ISCF) to encourage international collaboration, and with the overall aim of promoting global good practices and accelerating progress in biomedical science

2004First derivation of dopaminergic cells from human embryonic stem cells, a hope for Parkinson's disease treatment (USA)International Consortium of Stem Cell Networks (ICSCN) is initiated, which aims to unify international efforts to make stem cell therapy a reality for a broad range of debilitating diseases

2005First evidence for human bone cancer stem cells (USA)James Till and Ernest McCulloch win the Lasker Prize for experiments that first identified stem cells and set the stage for all current research on adult and embryonic stem cells

2006Normal mammary stem cells demonstrated in adult mice (Australia, Canada, US)First induced pluripotent stem cells (iPS) generated by reprogramming adult mouse skin cells. The altered iPS cells have characteristics similar to embryonic stem cells (Japan)

2007Mario Capecchi, Martin Evans and Oliver Smithies win the Nobel Prize for Physiology for Medicine for discoveries enabling germline gene modification in miceFirst physical identification and localization of mammalian intestinal stem cells (Holland)First evidence for human colon cancer stem cells (Canada)

2008Sam Weiss is awarded the Gairdner Prize for the discovery of neural stem cells

2009John Gurdon and Shinya Yamanaka win the Lasker Prize for discoveries in nuclear reprogramming. Yamanaka is also awarded the Gairdner PrizeiPS cells created with minimal residual genomic alteration (Canada)

2010Adult cells reprogrammed directly to neurons, cardiac muscle and blood cells (Canada, USA)iPS cells created by transfection of mRNA (USA)First clinical trial of human embryonic-derived stem cells for treatment of spinal cord injury (USA)

2011Isolation of multipotent human blood stem cells capable of forming all cells in the blood system (Canada)

2012John Gurdon and Shinya Yamanaka win the Nobel Prize in Physiology or Medicine for the discovery that mature cells can be reprogrammed to become pluripotent

Stem Cells ApplicationFrom Alzheimer’s to arthritis, blindness, burns, cancer, diabetes, heart disease, liver disorders, multiple sclerosis, Parkinson’s, spinal cord injury, stroke… Stem cells have been proposed as candidates to treat diseases and disorders of every organ of the human body.

Cell-based TherapiesHistorically, donated organs have been transplanted and medical devices implanted to replace failing systems. In the case of the former, the need far outweighs the available supply and, in both cases, the risks and costs are high. Side effects may limit the effectiveness or feasibility of drug, radiation or surgical interventions. Advances in biotechnology have led to the identification and replication of specific substances — such as sugars, amino acids, neurotransmitters and hormones — that are deficient in some degenerative diseases. While administering these substances as medication can overcome some of the limitations of more traditional pharmaceutical products, such as lack of specificity, there is no synthetic technology that can deliver them to the precise sites of action under the appropriate physiological regulation and dosage, or for the duration required to cure the condition. Cells, however, do this naturally.

Tools for ResearchOur understanding of human biology — the mechanisms and processes that allow humans to live, breathe, think and create — is still quite limited. It took nearly 200 years after discovery the of the cell in the mid 1600s, before it was proposed that all living things are made up of cells. And it wasn't until the late 1990s that science — in fact our own Scientific Advisory Board member Dr. Fred Gage — overturned the popular notion that the brain neurons with which we are born must last us a lifetime, by showing that adult brains can indeed generate new neurons — from stem cells. The identification and isolation of stem cells is a relatively recent scientific development. But, according to the UK Stem Cell Foundation, over 2,000 research papers on stem cells are now being published in reputable scientific journals every year. The fact is, we have much to learn from stem cells.

Drug Discovery and DevelopmentFor every drug used clinically to treat a disease, more than 6,000 chemical compounds are synthesized and screened to uncover lead candidates; over 90 percent of the drugs that make it to clinical trials are not approved for use. On average, the process takes approximately 12 years from lead identification to market approval and costs nearly US$1 billion. One reason for this high rate of failure may be inaccurate disease models. Stem cells can be induced to differentiate into cell types that retain more similarity to specific tissues than current models. They can even be genetically reprogrammed to produce cells emulating targeted genetic disorders, offering a more accurate and efficient platform for the drug discovery and development process.

StemCells scientists have already developed stem-cell based disease models for use in screening and toxicity assays in vitro, as well as the corresponding in vivo models required for preclinical evaluation.

Importance on Medicine Field

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STEM CELLS VIDEO

Stem cells are unique in their ability to divide and regenerate themselves and in their ability to remain specialized or unspecialized in the tasks of the human body. Because of these unique traits, these cells hold a great deal of promise in helping us learn about disease and develop treatments.

Many diseases, such as cancer, are the result of uncontrolled cell division, so learning how and why stem cells divide so many times may unlock the mystery of those conditions. The stem cells' regenerative properties may prove useful in developing treatments for conditions including diabetes, heart disease, Parkinson's disease, spinal cord injuries and strokes. To date, though, the ability to research medical treatments using stem cells has been limited because the use of embryonic stem cells is very controversial.

Bioethics is an activity; it is a shared, reflective examination of ethical issues in health care, health science, and health policy. These fields have always had ethical standards, of course, handed down within each profession, and often without question. About forty years ago, however, it became obvious that we needed a more public, and more critical, discussion of these standards.

Bioethics is that discussion. It takes place in the media, in the academy, in classrooms, and in labs, offices, and hospital wards. It involves not just doctors, but patients, not just scientists and politicians but the general public. Traditional ethical standards have been articulated, reflected on, challenged, and sometimes revised; standards for new issues have been created – and then challenged and revised. The conversation is often sparked by new developments, like the possibility of cloning. But bioethics also raises new questions about old issues, like the use of placebos and the treatment of pain.

What is Bioethics?

Bibliography

http://www.medicalnewstoday.com/info/stem_cell/

http://www.stemcellnetwork.ca/index.php?page=stem-cell-timeline

http://www.stemcellsinc.com/science/stem-cell-applications.htm

http://curiosity.discovery.com/question/why-stem-cells-important

http://www.bioethics.msu.edu/about/whatisbioethics

ConclusionWith the Stem Cells we can learn more about the D.N.A. applications and its functions to improve the human knowledge about it. Stem Cells help us to develop new living organisms, and the study of them, help us to advance forward into the field of biotechnology and genetics, to know more about the cells and how they grow and develop, improve our medicine skills by the study of stem cells, find disease treatments, and much more.

Stem Cells are the base of all the cells that live in an organism, and if we study them, we will improve new technologies and new organisms as clones, technologies that involves humans and machines movement & more.