Penn study finds hyperbaric oxygen treatments mobilize stem cells
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Penn study finds hyperbaric oxygen treatments mobilize stem cells
Recovery of injured and diseased tissue the ultimate goal
According to a study to be published in the American Journal of Physiology-Heart and Circulation Physiology, a typical course of hyperbaric oxygen treatments increases by eight-fold the number of stem cells circulating in a patient's body. Stem cells, also called progenitor cells are crucial to injury repair. The study currently appears on-line and is scheduled for publication in the April 2006 edition of the American Journal.
Stem cells exist in the bone marrow of human beings and animals and are capable of changing their nature to become part of many different organs and tissues. In response to injury, these cells move from the bone marrow to the injured sites, where they differentiate into cells that assist in the healing process. The movement, or mobilization, of stem cells can be triggered by a variety of stimuli – including pharmaceutical agents and hyperbaric oxygen treatments. Where as drugs are associated with a host of side effects, hyperbaric oxygen treatments carry a significantly lower risk of such effects.
"This is the safest way clinically to increase stem cell circulation, far safer than any of the pharmaceutical options," said Stephen Thom, MD, Ph.D., Professor of Emergency Medicine at the University of Pennsylvania School of Medicine and lead author of the study. "This study provides information on the fundamental mechanisms for hyperbaric oxygen and offers a new theoretical therapeutic option for mobilizing stem cells."
"We reproduced the observations from humans in animals in order to identify the mechanism for the hyperbaric oxygen effect," added Thom. "We found that hyperbaric oxygen mobilizes stem/progenitor cells because it increases synthesis of a molecule called nitric oxide in the bone marrow. This synthesis is thought to trigger enzymes that mediate stem/progenitor cell release."
Hopefully, future study of hyperbaric oxygen's role in mobilizing stem cells will provide a wide array of treatments for combating injury and disease.
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This article is available on the web at: ajpheart.physiology.org
PENN Medicine is a $2.7 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.
Penn's School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #4 in the nation in U.S. News & World Report's most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.
Penn Health System comprises: its flagship hospital, the Hospital of the University of Pennsylvania, consistently rated one of the nation's "Honor Roll" hospitals by U.S. News & World Report; Pennsylvania Hospital, the nation's first hospital; Presbyterian Medical Center; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home health care and hospice.
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ajpheart.physiology.org
Stem cell mobilization by hyperbaric oxygen
Stephen R Thom1, Veena M Bhopale2, Omaida C Velazquez3, Lee J Goldstein3, Lynne H Thom2*, and Donald G Buerk4
1 Emergency Medicine, University of Pennsylvania, Philadelphia, PA, USA; Institute for Environmental Medicine, University of Pennsylvania, Philadelphia, PA, USA
2 Emergency Medicine, University of Pennsylvania, Philadelphia, PA, USA
3 Surgery, University of Pennsylvania, Philadelphia, PA, USA
4 Physiology, University of Pennsylvania, Philadelphia, PA, USA
* To whom correspondence should be addressed. E-mail: meadowln@comcast.net.
We hypothesized that exposure to hyperbaric oxygen (HBO2) would mobilize stem/progenitor cells from the bone marrow by a nitric oxide (.NO) dependent mechanism. The population of CD34+ cells in the peripheral circulation of humans doubled in response to a single exposure to 2.0 atmospheres absolute (ATA) O2 for 2 hours. Over a course of twenty treatments, circulating CD34+ cells increased eight-fold, although the over-all circulating white cell count was not significantly increased. The number of colony-forming cells (CFCs) increased from 16 ± 2 to 26 ± 3 CFCs/100,000 monocytes plated. Elevations in CFCs were entirely due to the CD34+ sub-population, but increased cell growth only occurred in samples obtained immediately post-treatment. A high proportion of progeny cells express receptors for vascular endothelial growth factor-2 and for stromal derived growth factor. In mice, HBO2 increased circulating stem cell factor by 50%, increased the number of circulating cells expressing stem cell antigen-1 and CD34 by 3.4-fold, and doubled the number of CFCs. Bone marrow .NO concentration increased by 1008 ± 255 nM in association with HBO2. Stem cell mobilization did not occur in knock out mice lacking genes for endothelial .NO synthase. Moreover, pre-treatment of wild type mice with a nitric oxide (.NO) synthase inhibitor prevented the HBO2-induced elevation in stem cell factor and circulating stem cells. We conclude that HBO2 mobilizes stem/progenitor cells by stimulating .NO synthesis. |
