Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

'Seeing' stem cells helps in fight against peripheral arterial disease

11.03.2009
Unique interventional radiology research puts puzzle pieces together in regenerating blood vessels to open clogged arteries, uses firefly-like bioluminescence imaging agent

Interventional radiologists are fitting together the puzzle pieces of how to use stem cells to create new or more blood vessels to treat peripheral arterial disease (PAD) in those individuals with extensively narrowed or clogged arteries.

That puzzle may be closer to being solved in light of recent successful techniques that use simple imaging to view and locate transplanted stem cells and to confirm that they remain alive in the body once injected, notes a study presented at the Society of Interventional Radiology's 34th Annual Scientific Meeting.

PAD, which affects about 10 million Americans, is a chronic disease that progressively restricts blood flow causing poor blood circulation (generally in the legs) and if left untreated can lead to serious medical complications, including heart attack, stroke, amputation and death. Many people can manage the symptoms of PAD and stop its progression through lifestyle changes. If lifestyle changes are not enough, additional medical treatment may be needed, including prescribed medicine to prevent blood clots, lower blood pressure and cholesterol and control pain.

Interventional radiologists treat severe cases of PAD with minimally invasive treatments, including angioplasty and insertion of stents. "However, some patients have extensive disease—with so many blood vessels affected—that they're difficult to treat," said Frank Wacker, M.D., interventional radiologist at Johns Hopkins School of Medicine in Baltimore, Md. That's where stem cells—and image-guided stem cell therapy—come in. "One day, stem cells may enable the targeted delivery of cellular treatments to PAD patients who may be facing amputation and death.

It will be important to deliver the right amount of drug treatment to the right place, thus allowing tailored treatment for individual patients," said Wacker. "The use of C-arm CT for image-guided delivery in the angio lab enabled us to precisely target cell delivery in relationship to blood vessels without transferring to a separate CT scanner to obtain the similar information," he added. Stem cell therapy may provide interventional radiologists with a new weapon to fight PAD, a disease that affects 12 to 20 percent of Americans age 65 and older.

"To develop new stem cell treatments for PAD, we need suitable noninvasive methods to track the fate of stem cells clearly inside the body," said veterinary radiologist Dara L. Kraitchman, V.M.D., Ph.D., an associate professor at Johns Hopkins School of Medicine. Transplanting stem cells derived from bone marrow (not embryonic stem cells), accompanied by necessary immune-suppressing drugs, has had mixed results. Rejection by the body's immune system is a likely reason for transplant failure. Because X-ray agents are toxic to stem cells, tracking of stem cell therapy cannot be done by directly labeling the stem cells themselves.

Hopkins researchers used a new technique that encloses stem cells in an alginate capsule or "bubble" made from seaweed that contains stem cells to create factors to recruit the building of new vessels along with an X-ray–visible contrast agent. Tested in a rabbit model for the first time, the bubble prevents the body's immune system from reaching and attacking the transplanted cells. "We needed to figure out how to protect transplanted stem cells that are vulnerable to attack by a recipient's immune system and 'see' the cells to determine if they remained alive or not," said Kraitchman. "By making sure our protective covering for stem cells stayed intact, we were able to track where we put the stem cells and confirm whether they could survive," explained Kraitchman.

"These bubbles, which can be transplanted into a leg, can then be placed accurately at blocked blood vessels that need intervention," said Kraitchman. However, even visible with X-ray imaging, researchers could not determine if the stem cells within the bubble remained alive. Researchers then induced the stem cells within the bubble to produce luciferase, a bioluminescence imaging agent produced by fireflies—to "see" living stem cells. "We could 'see' the bubble via X-ray and tell if the stem cells remained alive as they lit up much like a firefly at night," said Kraitchman, who added that all agents used to form the bubble are approved by the Food and Drug Administration.

The future hope is to use adult stem cells extracted from a healthy donor's bone marrow and inject the cells into the patients' legs where circulation problems exist, stimulating the growth of new or more blood vessels in the leg, thus improving circulation, said Wacker. Previous studies in animals and other laboratory tests show that the injections of stem cells have such an effect and have prompted human trials, she added. Hopkins researchers took rabbit stem cells—separated from bone marrow in the lab—and injected them into the animal's hind quarter to track them. "Our research could eventually help PAD patients by providing a process for stem cells to thrive in the body and make more blood vessels or new blood vessels," he noted. "Using an animal model, we found that our research opens the door to delivering stems cells exactly where they are needed, allowing them to 'recruit' new blood vessels," added Wacker.

Bone marrow stem cells, which have the ability to renew themselves, could unlock the door to treat PAD with cell-based treatments. Stem cells are master or undifferentiated cells that have the ability to continuously divide and develop into other specialized types of cells. When conditions are just right, stem cells can begin to develop into specialized tissues and organs or turn into more specialized cells that are self-sustaining by replicating through cell division. Once healthy stem cells are harvested like blood for blood tranfusions, they could be injected into a diseased part of the body for growing healthier new blood vessels. Because of their uniqueness, researchers are exploring the use of stem cells for the treatment of life-threatening diseases.

Maryann Verrillo | EurekAlert!
Further information:
http://www.SIRweb.org

More articles from Health and Medicine:

nachricht New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University

nachricht Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>