MODERN DISEASE PREVENTION
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Cell Therapy has the potential to completely reinvent the way that medicine is conducted.

 

CLINICAL TRIALS SEEK TO IMPROVE WARRIORS' BURN CARE
by Donna Miles, American Forces Press Service
FORT DETRICK, Md., March 18, 2011 -- New hope is on the horizon for wounded warriors suffering debilitating burns as the Armed Forces Institute of Regenerative Medicine (AFIRM) and its partners at leading medical research centers launch three promising clinical trials.
     Burns are among the most painful and debilitating battlefield wounds and often turn deadly if infection sets in. In an effort to speed up the development of revolutionary new treatments for burns and other common battlefield injuries, the Defense Department launched AFIRM in 2008.
     Just three years into the program, AFIRM is seeing big signs of success as it helps advance technologies that use laboratory-grown tissues and biosynthetically developed compounds to treat injuries and illnesses. The ultimate aim of regenerative medicine is to enable patients' bodies to re-grow bones, skin and tissues -- even whole organs and limbs.
     Ten clinical trials already are under way or about to start in five areas specific to wounded warrior care. Three focus on burn repair. The idea, explained AFIRM Director Terry Irgens, is to push the envelope in exploring technologies that, while promising, are simply too expensive for the private sector to pursue alone. With funding from the Army Medical Research and Material Command, as well as the Navy, Air Force, National Institutes of Health, Department of Veterans Affairs and other public and private entities, AFIRM is helping advance technologies over the gap referred to as the valley of death. "It's where the existing technology ends, and there is a gap and nobody has the funding to get it to the next step," Irgens said.
     Two research consortia, made up of some of the best and brightest minds from 31 universities, are partnering with the U.S. Army Institute for Surgical Research at Fort Sam Houston, Texas, to help bridge that gap. The goal is to get an industry partner to step in and pick up where they leave off, Irgens said. "Once you get some good, promising data, that's when the commercial companies will come forward," he said.
     One of the new clinical trials, now entering its second phase, involves spraying a patient's own healthy cells onto the burned area. Seven patients already are enrolled in the trial, with a quota of 106 to participate based on the Federal Drug Administration protocol, Irgens said. As many as a dozen hospitals will be involved in the trial, with the Army Institute for Surgical Research expected to join it this summer.
     Dr. Smita Bhonsale, AFIRM's deputy director for science and technology, explained how the spray treatment works. The patient is rolled into the operating room, where doctors harvest a postage-stamp-size piece of skin from an unburned part of the body. The biopsy is broken apart into single cells, which are then suspended in a gel-like solution so they can multiply and create new skin tissue. Within a matter of hours, the cells are sprayed onto the patient's burns, covering an area up to 80 times the size of the original biopsy. The procedure requires no skin grafts and, because the cells are grown from the patients' own tissue, there's no risk of rejection.
     Another clinical trial, also entering its second phase, will use the patient's own healthy skin cells and multiply them in a flask under laboratory conditions. But rather than spraying the new cells onto the patient, doctors will apply the new cells as sheets of skin. Up to 14 patients are expected to participate in that clinical trial, to be conducted at the Army Institute for Surgical Research.
     Unlike the spray technology that's effective only on more superficial burns, this process can be used to treat patients with more severe, third-degree burns, Bhonsale explained. It eliminates the need for extensive and repeated skin grafting, and because it uses the patient's own skin cells, the body won't reject the new cells. While promising, the technology isn't without its drawbacks. The new skin takes up to six weeks to grow, requiring other temporary dressing to prevent infection and protein loss.
     A third clinical trial, now entering its second phase, will use a biosynthetic skin substitute to treat deep, third-degree burns. Thirty patients are expected to participate at four proposed sites, including the Army Institute for Surgical Research. The advantage of biosynthetic skin is that it can be developed in a laboratory setting and put into storage in a refrigerator until it's needed, explained Army Lt. Col. Brian Moore, AFIRM's deputy director.
     "This is something we are very interested in because we can grow a lot of it and then put it on the shelf," he said. "Then when someone gets burned, we can take that off the shelf and apply it." Because burn patients could receive this treatment immediately, they have less risk of infection and protein loss. And, unlike skin from cadavers, which typically is used as a temporary wound covering for burn patients, the biosynthetic skin contains substances that help the body better accept future skin grafts, Moore explained.
     But there's a down side to this treatment, too. Biosynthetic skin is a temporary fix, and must be removed later and replaced with living cells. Also, the new cells have no pigmentation or sweat glands, but Bhonsale said scientists already are at work on the next-generation technology to address the shortcoming.
     Although all of the clinical trials are being conducted independently, Irgens said the synthetic skin, if it achieves FDA approval, could someday allow burn patients to begin healing until their own harvested cells are able to take over.
     As the clinical trials go on, AFIRM is exploring a broad range of other products and technologies to better treat burn patients. One is a specially designed "skin gun" that sprays a solution of cells and water onto burn areas without injuring the cells.
     Another new device, called the BioPrinter, looks like a typical ink-jet computer printer. But instead of different-colored inks, its cartridges are filled with skin cells grown from the patient's own healthy cells. The printer sprays them onto the wound to promote a healthy recovery.
     AFIRM also is working to develop better bandages to promote burn healing and burn treatments using molecular iodine, the spice curcumin found in Indian curries, and stem cells from amniotic fluid, placenta, bone marrow and fat. Irgens emphasized that technologies being advanced by AFIRM all have to go through a FDA approval process and won't be delivered to the marketplace for at least three to five years. "FDA is very particular, and we want to make sure everything is safe," he said. "That's the first concern we all have. We do not want to harm any patients. We want to make them better."
     But once the approvals come and the technologies advance to the mainstream, Irgens said he believes the work started under the AFIRM program will have a far-reaching impact. "We feel this is very critical therapy. This is going to change the landscape, once this gets approved," he said. "It undoubtedly is going to move the level of care up a notch." That will have a huge impact on wounded warriors suffering from burns, Moore said.
     "The big thrust behind this is trying to restore people back to normalcy," he said. "You will never completely restore that functionality they had prior to the injury. But at least you will allow them to have some kind of normalcy and functioning in their day-to-day activities." The benefit will extend far beyond the military, Irgens said. "We are not developing anything military-unique," he said. "We are developing technology that could support mankind, both civilian and military." 
REGERNERATIVE MEDICINE
Study finds induced pluripotent stem cells match embryonic stem cells in modeling human disease
     Stanford University School of Medicine investigators have shown that induced pluripotent stem (iPS) cells, viewed as a possible alternative to human embryonic stem cells, can mirror the defining defects of a genetic condition — in this instance, Marfan syndrome — as well as embryonic stem cells can. An immediate implication is that iPS cells could be used to examine the molecular aspects of Marfan on a personalized basis. Embryonic stem cells, on the other hand, can’t do this because their genetic contents are those of the donated embryo, not the patient’s.
     This proof-of-principle regarding the utility of induced pluripotent stem cells also has more universal significance, as it advances the credibility of an exciting approach that’s been wildly acclaimed by some and viewed through gimlet eyes by others: the prospect of using iPS cells in modeling a broad range of human diseases. These cells, unlike embryonic stem cells (ESCs), are easily obtained from virtually anyone and harbor a genetic background identical to the patient from which they were derived. Moreover, they carry none of the ethical controversy associated with the necessity of destroying embryos.
     “Our in vitro findings strongly point to the underlying mechanisms that may explain the clinical manifestations of Marfan syndrome,” said Michael Longaker, MD, professor of surgery and senior author of the study, which was published online Dec. 12 in Proceedings of the National Academy of Sciences. Longaker is the Dean P. and Louise Mitchell Professor in the School of Medicine and co-director of the school’s Institute for Stem Cell Biology and Regenerative Medicine. The study’s first author is Natalina Quarto, PhD, a senior research scientist in Dr. Longaker’s laboratory.
     ...
     In this study, both iPS cells and embryonic stem cells carrying a mutation that causes Marfan syndrome showed impaired ability to form bone, and all too readily formed cartilage. These aberrations mirror the most prominent clinical manifestation of the disease.
     Discovered in 2006, induced pluripotent stem cells, or iPS cells, are derived from fully differentiated tissues such as the skin. Yet they harbor the same capacity of embryonic stem cells to differentiate into all the tissues of the body as well as to replicate for indefinite periods in a dish. Because they offer an ethically uncomplicated alternative to embryonic stem cells, iPS cells have fueled the hope that they can replace ESCs in scientists’ efforts to analyze, in a dish, the cellular defects ultimately responsible for diseases ranging from diabetes to Parkinson’s and even such complex conditions as cardiovascular disease and autism.
     One hope for iPS cells is to be able to differentiate them in a dish into tissues of interest — say, nerve cells of a patient with Parkinson’s or autism — and study these resulting cells’ characteristics with an eye to understanding the disease in a patient-specific way. This would be impossible to do with embryonic stem cells, unless ESCs from donated human eggs could be modified through the so-far insurmountable feat of substituting a patient’s own genetic material into these eggs to reflect the patient’s own genetic background.
     While scientists have set the goal of using these cells for more than research purposes — developing therapeutic applications in regenerative medicine — that prospect is more distant. Scientists will have to develop the capacity first to repair within such cells, whether iPS or ESC, the genetic defects determined to be responsible for a patient’s condition, and then differentiate the cells in bulk into the affected tissue, which could be used for regenerative medicine. Again, iPS cells in theory might be a better bet because, being initially derived from a particular patient, they could differentiate into tissues that are less likely to provoke graft rejection than similar tissues produced using a donor embryo’s ESCs.
     However, a number of studies have reported subtle differences between iPS cells and ESCs, implying that the two may not be equivalent. Experts have wondered whether these differences may render iPS cells inadequate substitutes for ESCs in modeling disease states. Dr. Longaker said this study suggests otherwise.
     The opportunity for a head-to-head comparison of ESCs and iPS cells arose serendipitously when Barry Behr, PhD, professor of obstetrics and gynecology and director of the Stanford Fertility & Reproductive Medicine Center, performed pre-implantation genetic diagnosis to select embryos for in vitro fertilization. Professor Barry Behr and Renee Reijo Pera, PhD, professor of obstetrics and gynecology and director of the Stanford Center for Reproductive and Stem Cell Biology, discovered that one candidate embryo carried a genetic mutation that causes Marfan syndrome. This embryo was thus not deemed fit for implantation. But it was a potential source of embryonic stem cells, each of which would carry the Marfan-causing mutation. So, rather than discarding or storing it, the researchers received permission to derive the embryonic stem cells Dr. Longaker’s team studied. (Both Behr and Reijo-Pera are co-authors of the study.)
     What followed was a collaboration featuring an all-star cast that included senior faculty members from several departments in the medical school as well as researchers at the University of Naples Federico II in Italy. The researchers generated ESCs from the Marfan-carrying embryo. They also obtained skin biopsies from Marfan patients from another Stanford co-author, Uta Francke, MD, professor of genetics and of pediatrics, and used cells called fibroblasts from these samples to derive iPS cells by means of what have now become routine procedures.
     “Here we had both iPS cells and embryonic stem cells side by side in culture dishes, both containing the defective gene responsible for Marfan. This was a perfect opportunity to compare them head to head,” Longaker said. When they did that, Longaker, Quarto and their associates found that both the iPS cells derived from the skin of Marfan patients and the ESCs from the embryonic Marfan carrier exhibited aberrations identical to those that characterize the disorder’s observed skeletal symptoms — a diminished capacity to form bone and a heightened propensity for forming cartilage instead.
     The scientists began the study with the knowledge that mutations causing Marfan syndrome are found in a gene that codes for a protein called FIBRILLIN-1. Importantly, FIBRILLIN-1 is known, in turn, to inhibit the activity of an intercellular signaling molecule named TGF-beta. Mouse studies have indicated that the absence or mutation of FIBRILLIN-1 results in a failure of this inhibition. This study showed for the first time in humans that the reason for stem cells’ failure to form bone and overzealous conversion to cartilage directly resulted from their consequent exposure to more, and more-activated, TGF-beta than normal people’s cells are.
     The success of iPS cells in faithfully reproducing Marfan’s cellular and molecular defects every bit as well as ESCs do may allow the disease to be studied (and, in the long run, even treated) in a case-by-case manner. While Marfan is a single-gene disorder, it can and does result from any of a large number of mutations to that one gene — upward of 600 have been identified so far —which manifest as a spectrum of subtle differences in symptoms from one patient to the next.
     The study was funded largely by a grant from the California Institute for Regenerative Medicine, with additional funding from the National Institutes of Health.
BRUCE GOLDMAN. Study finds iPS cells match embryonic stem cells in modeling human disease. Inside Stanford Medicine, Stanford University School of Medicine. 12 DEC 2011. Accessed 14 December 2011
http://med.stanford.edu/ism/2011/december/marfan.html
 
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