As mentioned in the section on Stem Cells in depth:
By figuring out what makes a stem cell pluripotent (able to form any type of cell), biologists are now able to create stem cells from adult cells simply by turning on certain genes -- these cells are named â€œinduced pluripotent stem cellsâ€� or IPS.
This is possible because every cell has a complete set of genes. Some of the genes in nature get switched on to make that cell into a particular type of cell. Biologists are now able to control that process in many areas.
.....the identity of a cell can be re-engineeredâ€”that an adult cell can be [directly] reverted to its embryonic state. This paradigm-shifting concept has opened up whole new avenues of research.â€�â€¦..â€œInduced pluripotent stem cells have already begun to revolutionize medicine. They provide much-needed models of rare and complex disease states while providing sources of cells that may one day be used to replace those that are either worn out or compromised by degenerative diseases.â€�
Using these techniques, scientists aim to someday be able to take a patient's own cells, say skin cells, change them into heart or brain cells, and then insert them back into the patient to fix damaged tissues.
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 diseaseâ€¦â€¦.
In people who suffer from type 1 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.
In a testament to the revolutionary potential of the field of regenerative medicine, in which scientists are able to create and replace any cells that are at fault in disease, the Nobel Prize committee on Monday awarded the 2012 Nobel in Physiology or Medicine to two researchers whose discoveries have made such cellular alchemy possibleâ€¦â€¦..
In 2006, while at Kyoto University, Yamanaka stunned scientists by announcing he had successfully achieved what Gurdon had with the frog cells, but without using eggs at all. Yamanaka mixed four genes in with skin cells from adult mice and turned those cells back to an embryo-like state, essentially erasing their development and turning back their clock.
The four genes reactivated other genes that are prolific in the early embryo, and turned off those that directed the cells to behave like skin.
By that time, researchers had already shown that cells taken from embryos at their earliest stages could also yield such embryonic stem cells, but Yamanaka rewrote biology by demonstrating that it was possible to turn adult cells into stem cells â€” cells that are now known as induced pluripotent stem cells, or iPS cells â€” without the help of either an egg (and whatever factors within eggs that influence early development) or an embryonic cell.
Taken together, Gordonâ€™s and Yamanakaâ€™s discoveries have turned fundamental biological concepts on their head. Their experiments prove that every cell, whether young or old, in embryos or in adults, has a similar ability to reprogram itself to become â€œyoungâ€� again, and thus capable of becoming any cell in the body.
Whatâ€™s more, Yamanakaâ€™s advance provided a practical solution to a thorny issue plaguing researchers interested in pursuing stem cell biology: that the only source of human embryonic stem cells are embryos, which must be destroyed in the process â€” a problem that was morally sticky enough to compel President George W. Bush to issue in 2001 a ban on the creation of new stem cell lines from excess embryos discarded during fertility treatments (the ban was removed by President Barack Obama in 2009).
Yamanakaâ€™s method further creates the possibility for each patient to become his own resource for replacement cells â€” thus treating disease. Within weeks of Yamanakaâ€™s published report on his discovery in 2006, laboratories around the world had adopted the â€œYamanaka factors,â€� as they are called, to generate abundant lines of stem cells from skin and other mature cells. Within a year, Yamanaka had taken the next important step in his research â€” applying his achievements with mouse cells to human skin cells and turning them back to an embryo-like state.
â€œWhat we have is the discovery of a game-changer in terms of how we approach human disease in the coming years,â€� Dr. Deepak Srivastava, director of the Roddenberry Center for Stem Cell Biology and Medicine at the Gladstone Institutes, where Yamanaka completed a postdoctoral fellowship and remains a faculty member, said during a press conference celebrating the Nobel announcement on Monday. â€œIn the next five to 10 years we are likely to see the same technology regenerate organs and create new treatments in regenerative medicine for many different human diseases.â€�â€¦..
Using Yamanakaâ€™s method, labs around the world have generated lines of heart, brain, nerve and muscle cells made from iPS cells from patients with diseases ranging from Alzheimerâ€™s to spinal cord injury and diabetes, all in the hope of understanding where in development these cells go awry and how to develop new treatments that address these aberrations.
Already, Yamanaka says that researchers at the Center for iPS Cell Research at Kyoto University, which he heads, are preparing to transplant retinal cells made from iPS cells into patients with macular degeneration next year. â€œThe biggest hurdle is safety,â€� he told reporters during a teleconference about moving iPS cells into the clinic. â€œEspecially in regenerative medicine, you have to double check that you wonâ€™t see any severe side effects in patients. We need to confirm the technology is safe.â€�
(This link was within the previous article under â€œMore.â€� Another link there is about restoring fertility in male mice.)
Are women born with all the eggs they'll ever have? Harvard scientists say possibly not. Their discovery of stem cells in human ovaries could someday help infertile women produce new eggsâ€¦..
If women are constantly producing new eggs, says Tilly [Jonathan Tilly, director of the Vincent Center for Reproductive Biology at Massachusetts General Hospital], that means it may be possible to intervene with the appropriate hormones or growth factors to help ovaries produce more eggs or to improve egg quality in order to reverse infertility.
It may also mean that current ideas about aging and waning fertility may be overturned as well. Recent mouse studies showed that when oocyte [egg] stem cells were removed from menopausal female mice and transferred into younger mice, the stem cells were able to make viable eggs. â€œWhen they transferred the tissue into a young ovarian environment, the stem cells woke back up and, lo and behold, a new population of oocytes formed,â€� says Tilly.
â€œThat tells us that perhaps ovarian failure at menopause isnâ€™t incompatible with the idea of these cells existing. Maybe we need to rethink how menopause is happening and if these cells are still there, but itâ€™s the organs that are failing with age, what does that mean down the road in terms of clinical interventions?â€�
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