There are many ways in which human stem cells can be used in research and the clinic. Studies of human embryonic stem cells will yield information about the complex events that occur during human development. A primary goal of this work is to identify how undifferentiated stem cells become the differentiated cells that form the tissues and organs. Scientists know that turning genes on and off is central to this process. Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell division and differentiation. A more complete understanding of the genetic and molecular controls of these processes may yield information about how such diseases arise and suggest new strategies for therapy. Predictably controlling cell proliferation and differentiation requires additional basic research on the molecular and genetic signals that regulate cell division and specialization. While recent developments with iPS cells suggest some of the specific factors that may be involved, techniques must be devised to introduce these factors safely into the cells and control the processes that are induced by these factors.
Human stem cells are currently being used to test new drugs. New medications are tested for safety on differentiated cells generated from human pluripotent cell lines. Other kinds of cell lines have a long history of being used in this way. Cancer cell lines, for example, are used to screen potential anti-tumor drugs. The availability of pluripotent stem cells would allow drug testing in a wider range of cell types. However, to screen drugs effectively, the conditions must be identical when comparing different drugs. Therefore, scientists must be able to precisely control the differentiation of stem cells into the specific cell type on which drugs will be tested. For some cell types and tissues, current knowledge of the signals controlling differentiation falls short of being able to mimic these conditions precisely to generate pure populations of differentiated cells for each drug being tested.
Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies. Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply. Stem cells, directed to differentiate into specific cell types, offer the possibility of a renewable source of replacement cells and tissues to treat diseases including maculardegeneration, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
Figure 3. Strategies to repair heart muscle with adult stem cells. Click here for larger image.
2008 Terese Winslow
For example, it may become possible to generate healthy heart muscle cells in the laboratory and then transplant those cells into patients with chronic heart disease. Preliminary research in mice and other animals indicates that bone marrow stromal cells, transplanted into a damaged heart, can have beneficial effects. Whether these cells can generate heart muscle cells or stimulate the growth of new blood vessels that repopulate the heart tissue, or help via some other mechanism is actively under investigation. For example, injected cells may accomplish repair by secreting growth factors, rather than actually incorporating into the heart. Promising results from animal studies have served as the basis for a small number of exploratory studies in humans (for discussion, see call-out box, "Can Stem Cells Mend a Broken Heart?"). Other recent studies in cell culture systems indicate that it may be possible to direct the differentiation of embryonic stem cells or adult bone marrow cells into heart muscle cells (Figure 3).
Cardiovascular disease (CVD), which includes hypertension, coronary heart disease, stroke, and congestive heart failure, has ranked as the number one cause of death in the United States every year since 1900 except 1918, when the nation struggled with an influenza epidemic. Nearly 2,600 Americans die of CVD each day, roughly one person every 34 seconds. Given the aging of the population and the relatively dramatic recent increases in the prevalence of cardiovascular risk factors such as obesity and type 2 diabetes, CVD will be a significant health concern well into the 21st century.
Cardiovascular disease can deprive heart tissue of oxygen, thereby killing cardiac muscle cells (cardiomyocytes). This loss triggers a cascade of detrimental events, including formation of scar tissue, an overload of blood flow and pressure capacity, the overstretching of viable cardiac cells attempting to sustain cardiac output, leading to heart failure, and eventual death. Restoring damaged heart muscle tissue, through repair or regeneration, is therefore a potentially new strategy to treat heart failure.
The use of embryonic and adult-derived stem cells for cardiac repair is an active area of research. A number of stem cell types, including embryonic stem (ES) cells, cardiac stem cells that naturally reside within the heart, myoblasts (muscle stem cells), adult bone marrow-derived cells including mesenchymal cells (bone marrow-derived cells that give rise to tissues such as muscle, bone, tendons, ligaments, and adipose tissue), endothelial progenitor cells (cells that give rise to the endothelium, the interior lining of blood vessels), and umbilical cord blood cells, have been investigated as possible sources for regenerating damaged heart tissue. All have been explored in mouse or rat models, and some have been tested in larger animal models, such as pigs.
A few small studies have also been carried out in humans, usually in patients who are undergoing open-heart surgery. Several of these have demonstrated that stem cells that are injected into the circulation or directly into the injured heart tissue appear to improve cardiac function and/or induce the formation of new capillaries. The mechanism for this repair remains controversial, and the stem cells likely regenerate heart tissue through several pathways. However, the stem cell populations that have been tested in these experiments vary widely, as do the conditions of their purification and application. Although much more research is needed to assess the safety and improve the efficacy of this approach, these preliminary clinical experiments show how stem cells may one day be used to repair damaged heart tissue, thereby reducing the burden of cardiovascular disease.
In people who suffer from type1 diabetes, the cells of the pancreas that normally produce insulin are destroyed by the patient's own immune system. New studies indicate that it may be possible to direct the differentiation of human embryonic stem cells in cell culture to form insulin-producing cells that eventually could be used in transplantation therapy for persons with diabetes.
To realize the promise of novel cell-based therapies for such pervasive and debilitating diseases, scientists must be able to manipulate stem cells so that they possess the necessary characteristics for successful differentiation, transplantation, and engraftment. The following is a list of steps in successful cell-based treatments that scientists will have to learn to control to bring such treatments to the clinic. To be useful for transplant purposes, stem cells must be reproducibly made to:
Also, to avoid the problem of immune rejection, scientists are experimenting with different research strategies to generate tissues that will not be rejected.
To summarize, stem cells offer exciting promise for future therapies, but significant technical hurdles remain that will only be overcome through years of intensive research.
Previous|VII. What are the potential uses of human stem cells and the obstacles that must be overcome before these potential uses will be realized?|Next
Read the rest here:
What are the potential uses of human stem cells and the ...
- Vet-Stem Medistem Cellmedicine Rheumatoid Arthritis Stem Cell Video.mp4 - March 23rd, 2011 [March 23rd, 2011]
- Holly Huber on Recovery: Stem Cell Therapy for Multiple Sclerosis Community Outreach Dallas, TX 2011 - March 26th, 2011 [March 26th, 2011]
- Macular Degeneration Improved With Stem Cells - March 31st, 2011 [March 31st, 2011]
- The Stem Cell Institute - April 2nd, 2011 [April 2nd, 2011]
- Cells That Heal Us From Cradle To Grave: A Quantum Leap in Medical Science - April 7th, 2011 [April 7th, 2011]
- Stem Cell Treatment Doing Wonders For Autistic Boy - April 9th, 2011 [April 9th, 2011]
- Explore Health Don Margolis part1 - April 15th, 2011 [April 15th, 2011]
- Explore Health Carlos Lima - One Step at a Time - May 19th, 2011 [May 19th, 2011]
- Stem Cell Patient Richard H. MS Treatment - May 20th, 2011 [May 20th, 2011]
- Visions Episode 92: Stem Cells Discovery - May 20th, 2011 [May 20th, 2011]
- Chemistry Tutorial 12.2c: Voltaic Cells - Practice - May 20th, 2011 [May 20th, 2011]
- Gene Doping: Super Athletes in 2008 Beijing Olympics - May 22nd, 2011 [May 22nd, 2011]
- Bacteria Cell - May 22nd, 2011 [May 22nd, 2011]
- Stem Cell Game 1 - Stem Cell Wrangler - May 24th, 2011 [May 24th, 2011]
- RSCI Don Margolis on Repair Stem Cells - May 30th, 2011 [May 30th, 2011]
- Mitosis - cell reproduction - June 1st, 2011 [June 1st, 2011]
- PROSTATE CANCER and stem cells.wmv - June 3rd, 2011 [June 3rd, 2011]
- Ah! So you can raise your power after all! - June 3rd, 2011 [June 3rd, 2011]
- BioEDEN European Stem Cell Bank - June 12th, 2011 [June 12th, 2011]
- Stem Cells Used to Grow Windpipes - June 15th, 2011 [June 15th, 2011]
- Stem Cell Game 3- Grow with the Flow - June 17th, 2011 [June 17th, 2011]
- Genetically modified kiwi - June 20th, 2011 [June 20th, 2011]
- Nurse Jackie Title Sequence - June 21st, 2011 [June 21st, 2011]
- Wrapsol Installation Video - Apple iPad - Original Front + Back - July 4th, 2011 [July 4th, 2011]
- Explore Health Don Margolis part2 - July 4th, 2011 [July 4th, 2011]
- Explore Health Carlos Lima and Christopher Reeve - July 10th, 2011 [July 10th, 2011]
- Oxidative stress: redox imbalance - July 14th, 2011 [July 14th, 2011]
- PROSTATE CANCER and stem cells - July 25th, 2011 [July 25th, 2011]
- Buy Priligy - July 28th, 2011 [July 28th, 2011]
- Stem Cell Therapy for Cerebral Palsy - Holly Catalano - August 2nd, 2011 [August 2nd, 2011]
- [Industry professional news channel itsTV] Weekly News Brief_0812 - August 20th, 2011 [August 20th, 2011]
- Sims 2 Mafia Story Part 7 - Farewell, Godfather/Stem Cell Medicine - August 30th, 2011 [August 30th, 2011]
- Doctors Use Stem Cells to Grow New Windpipes - August 31st, 2011 [August 31st, 2011]
- A New Way to Make Induced Pluripotent Stem Cells - September 5th, 2011 [September 5th, 2011]
- Stem Cell Research: Huntington's Disease - September 8th, 2011 [September 8th, 2011]
- Stem Cell Research: Huntington's Disease - September 8th, 2011 [September 8th, 2011]
- Regenerative Medicine and Applications of Stem Cell Research - September 9th, 2011 [September 9th, 2011]
- Genetically Modified T Cells Obliterate Chronic Lymphocytic Leukemia Tumors - September 9th, 2011 [September 9th, 2011]
- Stem Cell Treatment for Autism: Community Outreach Miami, Florida - May 2011 - September 10th, 2011 [September 10th, 2011]
- Susan Lim: Transplant cells, not organs - September 11th, 2011 [September 11th, 2011]
- Chiropractic Sports Medicine - September 11th, 2011 [September 11th, 2011]
- Living With and Managing Sickle Cell Disease - September 14th, 2011 [September 14th, 2011]
- WHO Finding Adds to Debate Over Mobile Phones, Brain Cancer - September 14th, 2011 [September 14th, 2011]
- Tionne "T-Boz" Watkins of TLC on Celebrity Medical Nightmares - September 16th, 2011 [September 16th, 2011]
- Tionne "T-Boz" Watkins of TLC on Celebrity Medical Nightmares - September 16th, 2011 [September 16th, 2011]
- Jello Biafra @ Rebellion 2011 - The Cell and Holiday in Cambodia - September 16th, 2011 [September 16th, 2011]
- CIRM Bridges: Training the Next Generation of Stem Cell Scientists - September 17th, 2011 [September 17th, 2011]
- David Kekich - Regenerative Medicine (Part 1/6) - September 17th, 2011 [September 17th, 2011]
- Coast To Coast AM - 9.6.2011 - 1/4 - US Collapse - September 18th, 2011 [September 18th, 2011]
- What Is Personalized Medicine? - September 21st, 2011 [September 21st, 2011]
- Stem Cells and a Brief Mention of Bacon - September 21st, 2011 [September 21st, 2011]
- Adult Stem Cell Sucess Stories - Laura Dominguez - September 23rd, 2011 [September 23rd, 2011]
- Is Regenerative Medicine Hype or Hope? - September 24th, 2011 [September 24th, 2011]
- How to Buy Bitcoin - by 'The Bitcoin Show' on OnlyOneTV.com - September 25th, 2011 [September 25th, 2011]
- How to Buy Bitcoin - by 'The Bitcoin Show' on OnlyOneTV.com - September 25th, 2011 [September 25th, 2011]
- Samsung Galaxy S2 Unboxing - September 25th, 2011 [September 25th, 2011]
- Finding Forest Planets (Brainstorm Ep8) - September 26th, 2011 [September 26th, 2011]
- iPhone 3GS mobile signal problem - The Computer Room Nottingham - September 30th, 2011 [September 30th, 2011]
- Mobile Devices' Location Tracking Raises Privacy Concerns - October 2nd, 2011 [October 2nd, 2011]
- Mobile Devices' Location Tracking Raises Privacy Concerns - October 2nd, 2011 [October 2nd, 2011]
- 21st Century Stem Cell Scientists: The CIRM Creativity Awards - October 4th, 2011 [October 4th, 2011]
- Towing An Iceberg to Africa, wait what? (Brainstorm Ep18) - October 4th, 2011 [October 4th, 2011]
- Need a New Liver? Then Just Print Yourself One - October 4th, 2011 [October 4th, 2011]
- The potential of amniotic fluid stem cells - October 4th, 2011 [October 4th, 2011]
- INCREDIBLE Nucleus Medical Media 2011 Demo - October 4th, 2011 [October 4th, 2011]
- Stem Cell Treatments for Autism: Community Outreach Miami, Florida - Juliana Ubinas - October 4th, 2011 [October 4th, 2011]
- Bruce Lipton: being a cell of Humanity - October 4th, 2011 [October 4th, 2011]
- Sensitiv Imago medical device - October 4th, 2011 [October 4th, 2011]
- New Lymphoma Drug SGN-35 - The Nebraska Medical Center - October 4th, 2011 [October 4th, 2011]
- Rockefeller University Press Conference 2011 Nobel Prize in Physiology or Medicine to Ralph Steinman - October 5th, 2011 [October 5th, 2011]
- Cerebral Palsy and Stem Cell Treatments - Tim's Testimonial - October 5th, 2011 [October 5th, 2011]
- Cerebral Palsy and Stem Cell Treatments - Tim's Testimonial - October 5th, 2011 [October 5th, 2011]
- Cerebral Palsy - October 5th, 2011 [October 5th, 2011]
- Stem Cells-Iran-08-28-2011 - October 5th, 2011 [October 5th, 2011]
- After Brain Study, New Questions About Mobile Phones - October 5th, 2011 [October 5th, 2011]
- Judy Roberson: Patient advocates drive stem cell scientists - October 5th, 2011 [October 5th, 2011]
- Geron's Embryonic Stem Cell Clinical Trial for Spinal Cord Injury - October 5th, 2011 [October 5th, 2011]
- Geron's Embryonic Stem Cell Clinical Trial for Spinal Cord Injury - October 5th, 2011 [October 5th, 2011]
- Dangers of Continued Use of Cell Phones-Pulse Sep 03, Part 2 - October 5th, 2011 [October 5th, 2011]
- 2011 Nobel Prize in Medicine - October 5th, 2011 [October 5th, 2011]