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Friday, April 27, 2012
Nanotech used to reduce amputation risk in diseased mice
OSAKA — A Japanese team has developed a method to more effectively treat people at risk of lower limb amputation because their blood supply is being restricted by arterial sclerosis.
The breakthrough is expected to be good news for those with peripheral arterial diseases that can increase amputation risks.
The team of researchers from Osaka City University and Kinki University improved treatments used to spur new blood vessel growth in the hind legs of mice by using a newly developed particle dubbed a nanoscaffold, the group reported in the U.S. Web journal PLoS One on April 19.
"We would like to give patients hope by making this new method ready for use in human treatment," said Dr. Shinya Fukumoto, an Osaka City University lecturer whose expertise covers endocrine and metabolic disorders.
In Japan, 100,000 to 150,000 people are believed to be at risk of lower limb amputation because of necrosis, or tissue death resulting from the narrowing of blood vessels caused by serious scleroses in their peripheral arteries.
Clinical trials for the new method are expected to start around 2015.
The nanoscaffold consists of biodegradable particles 50-100 micrometers in diameter to which cells can be attached. A micrometer is one-millionth of a meter.
The particles were used to spur growth of new blood vessels in the back legs of mice with arterial sclerosis.
In human angiogenesis treatment, bone marrow stem cells taken from patients are injected into other areas of their bodies affected by disease.
The injected cells release cytokines, a group of proteins that play a key role in blood vessel formation.
But about 70 to 80 percent of the injected cells disappear from the areas within 48 hours, limiting the effects of the treatment.
The effectiveness of the treatment is particularly low for diabetics and dialysis patients suffering from peripheral arterial diseases.
In the experiments on the mice, the team injected the nanoscaffold together with stem cells into their leg muscles and confirmed that the cells remained in the areas longer.
The use of the nanoscaffold boosted the limb survival rate fourfold, compared with treatment without the nanoscaffold, and the volume of newly formed vessels grew sevenfold, the team said.
The nanoscaffold can also be used with many other cells, including induced pluripotent stem (iPS) cells, which can develop into tissues of any kind, according to the team.
The particles can be used to treat strokes and heart attacks brought on by arterial sclerosis, the team added.