Cell reprogramming taken one step further.National Institutes of HealthPosted on 12/03/2007 10:37:07 PM PST by neverdem
Adult skin cells turned to pluripotent stem cells without a cancer-causing agent.
Cell reprogramming taken one step further.National Institutes of HealthShinya Yamanaka of Kyoto University in Japan has followed the announcement last week of his startling success in turning human skin cells to embryo-like stem cells, by reporting that he has done the same without the cancer-causing agent used in his original recipe.
The work brings scientists perhaps one step closer to the goal of being to use patient-matched stem cells for therapy.
Yamanaka first demonstrated his method for 'reprogramming' cells in mice. Last year he showed that he could produce pluripotent cells - cells that can turn into any of the roughly 220 cell types in the body - by using retroviruses to carry four genes into mouse skin cells1. The four genes reprogrammed the mouse cells to a state similar to those in the early embryo. He named the cells induced pluripotent stem (iPS) cells. But one of those genes, c-myc, is known as an oncogene, which can cause cancer. When Yamanaka produced live mice from embryos injected with these pluripotent cells, 20% of them developed tumours.
When last week Yamanaka reported similar success using human cells2, the announcement was tempered by the fact that such cells, made using c-myc, would pose a danger to transplant recipients.
In the further work published by Nature Biotechnology today3, Yamanaka shows that he can make both human and mouse iPS cells with just three factors, without using c-myc.
Last week James Thomson of the University of Wisconsin in Madison and his colleagues also reported a success with four factors that did not include c-myc4. But Thomson's result needs further work. He created his pluripotent cells using fetal not adult cells, whereas medical applications will require that adult cells be used. And Thomson's method has not tested in mice, he says. "We've tested these cells in mice and we know they are safe," says Yamanaka.
Before any pluripotent cells will be ready for use in human transplant therapies, however, much more work needs to be done. To reduce risks to recipients, the introduced genes may have to be eliminated altogether, perhaps by simulating their function with a small molecule, or the genes will have to be introduced in a way that does not require viral vectors.
iPSc ping
Bump
I wish medical science could do something right now about the lack of cartilege in my knee so I could avoid a knee replacement.
Nice!!
I’m so glad they’re working this angle seriously. Now that they know it can be done, they’ll be looking for ways to do it safely and in a large scale way. This is such a wonderful breakthrough!
The next step is to reverse the process -- given a stem cell, "freeze it" to the specific type required. That would get rid of the most difficult "wild growth" aspects of the fetal stem cells.
Interestingly, I think the theraputic possibilities are vast -- grow and replace damaged heart tissue. Grow and replace nerve tissues?
Reading your predicament makes me sad. Reprogramming and tissue regeneration still has a long way to go, IMHO, especially with connective tissue like tendons, ligaments and cartilage. Their blood supply is minimal. I hope I'm wrong.
Be that as it may, avoid a knee replacement until it can't wait, e.g. medical complications make it mandatory. That happened to my mom. She had both knees replaced just over seven years ago. She is ninety years old. She is still living independently.
Dr. Anthony Atala has built bladders so far. IIRC, they were working in seven patients. You can find two stories about him on FR using atala as a keyword. Enter atala a into PubMed's query box. You'll get a chronological list of his papers.
PubMed is huge. It may not be updated as soon as specific journals. Specific journals may be case sensitive and require a comma in order to do an author search, e.g. Atala, A
P.S. A terminal period was deliberately eliminated in the last example.
I really am avoiding a knee replacement, in spite of two surgeons recommending it. The problem is that I used to walk a couple of miles everyday, and I can’t do that anymore. Plus, I live in a 2 story house, and that’s an issue too. I wear an elastic knee brace, and that helps.
I talked to a woman yesterday who had a knee replacement, and she developed an infection afterward. On Sunday my brother went to a birthday party, and the woman hosting it said her knee pain is worse after her replacement because of scar tissue. Then again, there’s your mother who seems to be an amazing woman!
Gene Silencing Directs Muscle-Derived Stem Cells To Become Bone-Forming Cells
Human Fat Stem Cells Yield Bone Cells
Periosteal Cells Grow Cartilage, Bone, And Skeletal Muscle
Stem Cells Used To Repair Broken Bones
Genetically Engineered (Adult) Stem Cells Repair Rat Tendon
Findings Advance Use Of Adult Stem Cells For Replacement Bone
Doctors Test Ways To Grow Knee Cartilage (Adult Stem Cells)
Stem Cells Used To Help Those With Knee Pain
Study: Can Stem Cells Restore Meniscus?
Stem Cells Help Broken Bones Heal
What Is A Bone Marrow Transplant? (The Ethical/Effective Use Of Adult Stem Cells) Donors Needed
ADULT Stem Cells May Mend Arthritis Damage
ADULT Stem cells injected in horses for Joint Problems
Phillips Plastics to help develop orthopedics with stem cells
Healing Bone with Stem CellsSurgeons Hail Bone Stem Cell Breakthrough
Thank you
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.