Transplants without tears
Transplants without tears
Science Magazine (subscription) - USA
... multiple sclerosis, and lupus, in which traditional conditioning was considered too drastic. "it's an intriguing new approach," says stem cell biologist ...
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Transplants Without Tears
By Mitch Leslie
ScienceNOW Daily News
26 November 2007
A new treatment might allow patients to avoid some of the grueling side effects of bone marrow transplants. Researchers reported in the 23 November issue of Science that they can use a specific type of antibody to clear away old marrow stem cells in mice, allowing fresh ones to take their place. The discovery could allow patients to receive bone marrow without undergoing chemotherapy and other toxic procedures. Bone marrow transplants can ameliorate diseases such as sickle cell anemia by replenishing hematopoietic stem cells (HSCs) that spawn white and red blood cells. But before they receive this marrow, patients must typically undergo conditioning, a course of chemotherapy (and sometimes radiation) that wipes out immune cells that might attack the transplants and eliminates the existing, faulty HSCs. However, conditioning also devastates stem cells throughout the body, triggering hair loss, diarrhea, mental decline, and other side effects.
Searching for a gentler approach, postdoc Deepta Bhattacharya and immunologist Irving Weissman of the Stanford University School of Medicine in Palo Alto, California, and colleagues dosed mice with an antibody that ties up c-kit, a receptor on the surface of HSCs that promotes their division and survival. The antibody sent the number of HSCs in the animals' bone marrow plunging by more than 98% after 8 days, the researchers report. That seemed to clear space for new cells to rebuild the animals' immune systems. Six months after a bone marrow transplant, 90% of one type of immune cell were derived from transferred HSCs, the team found.
Weissman envisions that an HSC-removing antibody will be part of a two-pronged attack on illnesses such as sickle cell anemia, severe combined immunodeficiency, aplastic anemia, and thalassemia. First, patients would receive antibodies to suppress immune cells that might reject a bone marrow transplant; such antibodies are already in use, although they can cause flulike symptoms and other side effects. Then, an HSC-deleting antibody would make room for new stem cells. Weissman cautions, however, that researchers need to find a human antibody that performs as well as the mouse version. But if successful, the strategy could eliminate the need for chemotherapy and radiation and allow transplants for diseases, such as type 1 diabetes, multiple sclerosis, and lupus, in which traditional conditioning was considered too drastic.
"It's an intriguing new approach," says stem cell biologist and clinician David Scadden of Harvard Medical School in Boston, Massachusetts. But stem cell biologist Kateri Moore of Mount Sinai School of Medicine in New York City questions whether the antibody removes all HSCs. She notes that even without a transplant, HSC numbers rebound in mice within about 3 weeks of an antibody dose. Any HSCs spared by the antibody, she warns, could compete with newcomers for space or even produce T cells that attack the transplants.
Related site
More information on bone marrow transplants
http://sciencenow.sciencemag.org/cgi/content/full/2007/1126/2
Heading home.
A glowing stem cell transplant searches out a place to settle down.
Credit: Deepta Bhattacharya, Agnieszka Czechowicz, and Irving Weissman
__________________________________
Science 23 November 2007:
Vol. 318. no. 5854, pp. 1296 - 1299
DOI: 10.1126/science.1149726
Reports
http://www.sciencemag.org/cgi/content/abstract/318/5854/1296Efficient Transplantation via Antibody-Based Clearance of Hematopoietic Stem Cell Niches -- Czechowicz et al. 318 (5854): 1296 -- Science
Upon intravenous transplantation, hematopoietic stem cells (HSCs) can home to specialized niches, yet most HSCs fail to engraft unless recipients are subjected to toxic preconditioning. We provide evidence that, aside from immune barriers, donor HSC engraftment is restricted by occupancy of appropriate niches by host HSCs. Administration of ACK2, an antibody that blocks c-kit function, led to the transient removal of >98% of endogenous HSCs in immunodeficient mice. Subsequent transplantation of these mice with donor HSCs led to chimerism levels of up to 90%. Extrapolation of these methods to humans may enable mild but effective conditioning regimens for transplantation.
Institute of Stem Cell Biology and Regenerative Medicine, Departments of Pathology and Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
These authors contributed equally to this work.
* To whom correspondence should be addressed. E-mail: irv@stanford.edu
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a new hope for 'silent disease'
Waikato Times - Waikato,New Zealand
... breakthrough ms drug called tysabri. the drug is aimed at reducing relapses and slowing the progression of disability in relapsing ms. while mrs hebberd ...
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Hello Bill,
Thank you so much for your email. The enrollment criteria for the Phase I/II trial for Chondrogen allowed patients 18-60 years of age.
If you require any additional information or have any other questions, please don't hesitate to contact me.
Sincerely,
Erica
Erica Elchin
Phone: 443.545.1824
Fax: 443.545.1701
www.osiris.com
________
Ahead of the Bell: Lazard's Health Picks
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Analyst Joel Sendek said there is a substantial market for biotechnology company Acora Therapeutics Inc'sa Fampridine-SR beyond its use for walking ...
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Its lead drug, ATL1102, is in the advanced stages of a Phase 2a trial as a potential treatment for multiple sclerosis. Contact Information: Website: ...
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Medical News Today Tue, 27 Nov 2007 11:03 AM PST
The Bournemouth branch of the MS Society is urging people to pick up the phone and show their support for a project that could receive almost £100,000 and benefit people with multiple sclerosis (MS) across the region. [click link for full article]
Cast Your Vote Today To Help Day Centre, UK
The Bournemouth branch of the MS Society is urging people to pick up the phone and show their support for a project that could receive almost £100,000 and benefit people with multiple sclerosis (MS) across the region.
Remoulding Attitudes Toward Disability, UK
The MS Society has given its full support to a unique campaign launched by Leonard Cheshire Disability, which aims to challenge and change people's attitudes toward disability.The disability charity has teamed up with Aardman Animations to create Creature Discomforts, based on the much-loved Creature Comforts series but featuring the hallmark Plasticine characters voiced by people with disabilities including multiple sclerosis (MS).
Research Breakthrough Changes Ethics of Stem Cell Debate
CU Columbia Spectator - New York,NY,USA
Piggybacking on the work of two researchers from Kyoto University who this summer turned mice's skin cells into stem cells, two groups from Japan and the ...
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Osiris Therapeutics Announces Positive One Year Data from ...
Business Wire (press release) - San Francisco,CA,USA
Chondrogen is a preparation of mesenchymal stem cells specifically formulated for direct injection into the knee. The stem cells are obtained from the bone ...
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"Promoting stem cell research can contribute to solutions for this disease and others such as multiple sclerosis (MS) and amyotropic lateral sclerosis (ALS) ...
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Pedophiles have less brain white matter: Toronto study
http://www.cbc.ca/health/story/2007/11/28/pedophiles-study.html
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