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By John Schieszer
Medical Minutes 

Innovations in heart stents, cancer research

 


New dissolving electronic heart stents

Researchers have now come up with an electronic stent that can provide innovative therapy and then dissolve. It is now estimated that every year a half-million Americans undergo surgery to have a stent prop open a coronary artery narrowed by plaque. However, a major drawback with stents has been that sometimes the mesh tubes get clogged. Scientists are now reporting in the journal Nano that they have come with a new kind of multi-tasking stent that could minimize the risks associated with the procedure. It can sense blood flow and temperature. It can also store and transmit the information for analysis.

Doctors have been implanting stents to unblock coronary arteries for more than 30 years. The devices have been evolving. They have gone from bare metal, mesh tubes to coated stents that can release drugs to prevent reclogging. However, even the latest versions of stents are associated with some health risks. In recent years, there have been significant efforts to come up with stents that the body can absorb to minimize the risk that a blood clot will form.

Investigators are now reporting that they have developed and tested in animals a drug-releasing electronic stent that can provide diagnostic feedback by measuring blood flow. That is very important because it can tell when an artery starts narrowing. The device can also heat up on command to speed up drug delivery and it can dissolve once it’s no longer needed.

Men at high risk for prostate cancer may benefit from drinking green tea

If a man has been diagnosed for being at high risk for prostate cancer, he may want to start drinking green tea. New research suggests it may be helpful in the prevention of prostate cancer. A team of researchers at Moffitt Cancer Center in Tampa, Florida, has published results of a randomized trial that assessed the safety and effectiveness of the active components in green tea to prevent prostate cancer development in men who have premalignant lesions.

The researchers report that 20 percent of green tea is consumed in Asian countries where prostate cancer death rates are among the lowest in the world. Studies have shown that the risk of prostate cancer appears to be increased among Asian men who abandon their original dietary habits upon migrating to the U.S.

Substances in green tea called catechins inhibit cancer cell growth, motility and invasion. In addition, catechins stimulate cancer cell death and green tea catechins have been shown to prevent and reduce tumor growth in animal models. Epigallocatechin-3-gallate (EGCG) is the most abundant and potent catechin found in green tea responsible for these cancer prevention effects.

The Florida researchers conducted a 1 year trial in which they gave green tea catechins to men who had high-grade intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP). The researchers used decaffeinated green tea capsules called Polyphenon E that contained a mixture of catechins that predominantly contained EGCG.

The researchers compared Polyphenon E in 49 men to 48 men who did not receive the pills and found that the men who only had HGPIN at the beginning of the trial had a lower combined rate of ASAP and prostate cancer development with Polyphenon E. ASAP is an entity that reflects a broad group of lesions in the prostate with insufficient changes in the cells to be definitively diagnosed as prostate cancer.

Additionally, men on Polyphenon E had a significant decrease in prostate-specific antigen (PSA) levels. PSA is a biomarker that in combination with other risk factors is used to screen men for prostate cancer. High PSA levels signify a higher risk of prostate cancer.

3D printers for combating cancer

An international scientific team has successfully created a three-dimensional model of a cancerous tumor using a 3D printer. The model could ultimately help discover new drugs and cast new light on how tumors develop, grow and spread.

The 3D model consists of a scaffold of fibrous proteins coated in cervical cancer cells. A 10mm by 10mm grid structure, which is made from gelatin, alginate and fibrin, recreates the fibrous proteins that make up the extracellular matrix of a tumor. The grid structure is coated in Hela cells (a unique, “immortal” cell line that was originally derived from a cervical cancer patient in 1951).

The most effective way of studying tumors is in a clinical trial. However, ethical and safety limitations make it difficult for such studies to be carried out on a wide scale. To overcome this, two-dimensional models (consisting of a single layer of cells) have been created to mimic the physiological environment of tumors and test anti-cancer drugs in a realistic way. However, with the advent of 3D printing it may be possible to provide a more realistic representation of the environment surrounding a tumor. The researchers demonstrated this by comparing results from their 3D model with results from a 2D model.

After testing if the cells remained viable, or alive, after printing, the researchers examined how the cells proliferated. They also looked at how the cells expressed a specific set of proteins that help tumors spread. They found that 90 percent of the cancer cells remained viable after the printing process. In addition, the 3D model shared more similarities with a tumor than 2D models including a higher proliferation rate, higher protein expression and higher resistance to anti-cancer drugs.

“We have provided a scalable and versatile 3D cancer model that shows a greater resemblance to natural cancer than 2D cultured cancer cells,” said study investigator professor Wei Sun who is with Drexel University. “We can also use these models to test the efficacy and safety of new cancer treatment therapies and cancer drugs.”

John Schieszer is an award-winning national journalist and radio broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.

 
 

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