Tapping The Potential Of Adult Stem Cells: Peripheral Vascular Disease
Thursday, January 19, 2006 - Stem Cell Guru
It's encouraging to see a clinical trial on treating periperal vascular disease with adult stem cells commencing in America. We expect to start a similar trial in Thailand very soon. However, it's unfortunate that American patients will have to endure a half-liter bone marrow extraction when, in fact, a routine blood draw is all that is actually required.
Heartbeat
Tapping The Potential Of Adult Stem Cells
Can adult stem cells help regenerate the damaged blood vessels in patients with peripheral vascular disease?
Published: November/December 2005
A multidisciplinary team of researchers at the Indiana Center for Vascular Biology and Medicine is experimenting with a novel adult stem cell therapy, using patients' bone marrow cells that are involved in arterial formation and repair. The Stem Cell Mediated Angiogenesis Study is an FDA-approved Phase I clinical trial to examine how safe and effective adult stem cells are for stimulating the development of new blood vessels in the legs of patients with severe peripheral vascular disease--a painful condition that, according to the American Heart Association, affects approximately 12 million people. When blocked or destroyed, arteries in the leg are unable to transport essential nutrients and oxygen, resulting in tissue death and gangrene. Many patients suffering from advanced peripheral vascular disease often exhaust all conventional means of therapy and face amputation.
Researchers hope that the specialized adult stem cells--known as endothelial progenitor cells (EPCs), involved in the repair of the inner lining of blood vessels--will help restore enough blood flow to lower limbs to help regenerate blood vessels and avoid amputation.
One day, the innovative therapy might benefit other areas of the body, such as the heart muscle.
To learn more about the trial, the Post spoke with Michael Murphy, M.D., at the Indiana Center for Vascular Biology and Medicine at Indiana University School of Medicine.
Post: Could you outline your research utilizing adult stem cell-based therapy to treat cardiovascular disease?
Murphy: Basically in the last five years, researchers have isolated a cell in the bloodstream of humans called an endothelial progenitor cell--a special type of stem cell. Subsequent studies have demonstrated that the endothelial progenitor cell, or EPC, comes from the bone marrow. Clinical evidence from an NIH study showed that patients who have a greater number of cardiovascular risk factors--high blood pressure, diabetes or cigarette smoking--have fewer endothelial progenitor cells. The conclusion was that these cells are involved with arterial repair and may help prevent the development of atherosclerosis. The cells also participate in the development of new blood vessels. Animal studies have demonstrated that when EPCs from bone marrow are injected into lab animals, they develop new blood vessels in response.
Post: How do you retrieve and administer the adult stem cells in your study?
Murphy: Under anesthesia, we remove about 500 cc, or one-half a liter, of bone marrow from the patient--about 2 to 2 1/2 cups of bone marrow. We process the bone marrow in our stem cell laboratory at University Hospital. We separate out what we call the buffy coat--the mononuclear cell layer--by spinning the cell preparation at very high speeds.
To administer, we basically inject the cells, or the mononuclear cell fraction containing a subpopulation of progenitor stem cells, right into the calf muscle of the affected leg that has insufficient blood flow. In the future, we plan to grow the cells in culture and increase the number of endothelial progenitor cells before injecting. Right now, we have strict limitations on what we can do from the FDA, because this is the first such study in the United States.
There is evidence the injected progenitor ceils directly incorporate into new capillary beds and produce the necessary protein messengers--so-called cytokines--that induce existing blood vessels to grow.
By using the cells from the patient's own bone marrow, we avoid the problem of rejection and so avoid the ethical issue of using embryological cells.
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4 Comments:
Dr Murphy is far ahead of all American scientists. His studies have demonstrated the bone marrow stem cells are greater in number and more functional in developing new arteries that stem cells collected from peripheral blood.
There are significantly more stem cells in the bone marrow than in peripheral blood. That is why most researchers are using bone marrow and that is also why TheraVitae's technology is special.
Our technology allows us expand a very small number of stem cells found in the peripheral blood into a therapeutic number. There is no need to extract bone marrow from the patient. The process requires a blood donation; no anesthesia or other drugs.
As far as bone marrow stem cells being more "funtional" than peripheral blood stem cells - that's certainly not true in the case of cardiac stem cell therapy. Dr. Amit N. Patel from UPMC, who uses bone marrow in his US stem cell trials for heart failure has publicly stated that our cells are as effective as those collected from bone marrow. (He has accompanied many patients to Bangkok for treatment using VesCell.)
We feel that this will prove to be the case with PAD as well.
Time will tell.
Vescell indeed is ahead of all in the world currently in blood derived heart stem cell therapy, but not the only one doing it. Scripps Clinic in San Diego has already treated approximately 24 patients since 04' using a blood derived heart stem cell angioplasty therapy, very similar to the procedure of Vescell/Theravitae. They claim a 90% (varying degree of) success with all treated patients. The blood is processed into stem cells by Baxter International. In spring 06' St. Elizabeth Hospital in Boston and the Minn. Heart Institute, will also begin their blood derived heart stem cell therapy, using Baxter's proprietary technology for transfer of blood to adult stem cells. One of the Baxter patients was on the NBC Today show last week looking great. However, Theravitae has more experience, having treated over 80 patients; I would currently choose Theravitae. And who knows when the Baxter treatment will be available as a non-study actual paid treatment somewhere in the world. My guess is it will take 2 to 3 years. And, my understanding is it takes Baxter 2 to 3 weeks to process the blood, which speed may improve. Vescell's technology I am sure is better, and more proven. But it is important for Theravitae/Vescell to get more established in the West. Or else competiton from Baxter with their 50,000 employees and representatives at labs mostly in the americas and europe, with a 70 year history of blood processing, will present market problems down the road for Vescell/Theravitae. Does Vescell/Theravitae have any thoughts on the above?
Just to clarify:
Scripps, Minnesota and St. Elisabeth did the same study on 18 patients treated + 6 controls. The procedure is similar, but they treat the patients first with a drug to bring stem cells out of the marrow into the blood. This may be risky and could have severe side effects.
Points to note:
1. The Baxter process (spinning cells in a blender with magnets) is not new and has been around for years for cancer. In the last 10 years none of the cancer patients improved their heart function. As a matter of fact, it is not even proprietary (Multenny also does this).
2. It will not be on the market in 2 years. They have found that using bone marrow (they cannot use blood stem cells, falsity) causes calcification which does not matter when it is used for bone marrow transplants but does for the heart. In our opinion, even the best hope would be 10 years for anyone. After Vioxx and gene therapy scandals the FDA is extremely conservative.
3. Scripps initial trials were bone marrow based (yes 24). They or anyone else would have to restart from Phase I if they were to switch platform. As we know the doctor running the trial, this is not expected.
4. Not everyone is using the same type of stem cells. Virtually all labs that are using blood borne stem cells are using EPCs which are the basic building block of the cells which we use, i.e. APCs. They do not have the same characteristics. Both are 'fruit' but one is an apple and the other is a watermelon.
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