DAVID GRANOVSKY

Archive for April 30th, 2012|Daily archive page

microRNA – New Kid On The Block Has Journalistic Baggage

In STEM CELLS IN THE NEWS on April 30, 2012 at 3:58 am

“Duke University researchers used molecules called microRNAs to convert scar tissue (called fibroblasts) into heart muscle cells in a living mouse”

That’s great! Unfortunately, the author of the article foolishly decided to pit “microRNA – The New Kid On The Block” against the decade long reigning champ, Adult Stem Cells…and he needs to get his story straight.

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New Kids On The Block

From the start, the author presents almost no accurate information about adult stem cells, their decade of history, successes, studies, trials, patients treated, safety, efficacy and potency.  He is incredibly dated on the understanding of adult stem cells and straight up wrong/ignorant on many of his points.  His original 3 point comparison is to Embryonic stem cells, already shown to be far inferior to Adult Stem Cells in every way including their potency.  He then states Adult Stem Cells have: “…a limited capacity to form other types of cells” which is completely wrong. 

He then quotes the Duke University doctor, ‘The results of using these adult stem cells for tissue regeneration are “not as satisfying as one would like.” 

  • A. “not as satisfying as one would like.” is perhaps the most unscientific assessment I’ve ever heard 
  • B.  I’m surprised to hear this from the doctor as Duke University has had tremendous success utilizing stem cells in treating pediatric Cerebral Palsy/Ataxia 
  • C.  Would he be satisfied if there was a decade long history of cardiac tissue regeneration studies?  There is: http://repairstemcell.wordpress.com/heart-disease-treatment/
  • D.  Would he be satisfied if you could grow an entire heart from scratch, from a patients’ own stem cells?  You can.

 

I suppose the author is not entirely to blame as the assertion within the peer reviewed article is completely erroneous as well: “this is the first report of direct cardiac reprogramming in vivo.”  Wrong!

I would further question whether microRNA cells are “smart” like adult stem cells are.  Gene therapy to turn heart muscle scar tissue into heart muscle is great but then you have a scar shaped piece of heart muscle.  Does it beat in perfect time with the rest of the heart muscle or is it asynchronous?  Can it grow an entirely new heart from scratch as adult stem cells can? (No, it can not)

An adult stem cell grows a cardiac cell from it’s proverbial birth and the cardiac cells conform from ‘birth’ and as they develop to the surrounding tissue and work in unison with the adjacent cells.  It would appear the microRNA transforms the scar tissue at a later stage of the cells growth.  This is then perhaps an “older cell” with it’s own inherent programming and limitations. Prone to it’s own agenda, these doppelganger heart cells may cause conflicts with the existing cells and the rest of the heart muscle.

Just changing scar to muscle is only a fraction of what stem cells can do.  “Smart” adult stem cells will build the cells needed, put them in the places they are needed, create valves where valves are needed, capillaries if those are needed, bring dead heart tissue back to life and then some will migrate down to the pancreas and heal that as well.

microRNA gene therapy may have a long future of success and I am sure there are some applications which they will be great.  To compare them to adult stem cells in the context of regenerative medicine as the author has done, especially without a proper understanding of the safety and efficacy record of adult stem cells, especially in the field of cardiac regenerative medicine which has a decade long history (the longest of all practical and clinical research), is like bringing a rubber knife to a gun fight.

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Repairing the heart without using stem cells

By Alex Crees Published April 27, 2012 FoxNews.com

  • stem cell

When a person suffers a heart attack, scar tissue forms over the damaged areas of the heart, reducing the organ’s function.  However, in a recent study, scientists successfully turned this scar tissue into working heart muscle without the use of stem cells.

Duke University researchers used molecules called microRNAs to convert scar tissue (called fibroblasts) into heart muscle cells in a living mouse, improving the heart’s ability to pump blood.

According to the scientists, this process is much simpler than stem cell transplants and has none of the ethical concerns, making it a potential turning point in the science of tissue regeneration.

“Right now, there’s no good evidence stem cells can do the job,” senior author Dr. Victor Dzau, a James B. Duke professor of medicine and chancellor of health affairs at Duke University, told FoxNews.com.

Scientists believe embryonic stem cells are the best to use for tissue regeneration because they are pluripotent—meaning they can become any type of cell in the body.  However, Dzau said there have not been enough experiments done to prove how functional the stem cells are in regenerating tissues and whether or not they may form deadly tumors.

Additionally, there are ethical concerns about using cells derived from a human embryo, he said.

Meanwhile, adult stem cells avoid the controversy surrounding embryonic stem cells but have a limited capacity to form other types of cells.  The results of using these adult stem cells for tissue regeneration are “not as satisfying as one would like,” Dzau said.

Rather than stem cells, the new method developed by Dzau’s team uses microRNA molecules—which typically control gene activity—and delivers them into the scar tissue that develops after a heart attack.  The microRNAs are able to reprogram, or trick, the scar tissue into becoming heart muscle again instead.

Testing is still in its early stages, but so far, the method appears to be relatively easy, and the data looks very promising, according to the researchers.

“It’s a much simplified, feasible way of causing regeneration; very easy to use as therapy,” Dzau said.  “With stem cells, you have to take them from the embryo or tissue in the body, grow them in culture, and re-inject them—and then there can be technical and biological problems.

“With microRNA, after a heart attack you can simply convert some of the fibroblasts and tell them to become the right cell type and regenerate,” he said.

The method also has the potential to treat stroke, spinal cord injuries, chronic conditions such as heart disease—and even the normal damage that can come with aging.  It can feasibly be used for any type of organ in the body, though the process of converting the cells may be different for each organ.

“Right now, our work is proof of concept,” Dzau said, adding that the method must still be tested in then larger animals, and if successful there, it can move onto human clinical trials.  “But one could think about all these things of possibilities.  Could you use it to treat the disease of aging and losing brain cells?  Can you convert other cells in the brain to working brain cells?

“It’s a significant finding because it changes the way we think about regenerating tissues,” Dzau said.  “It breaks open a whole new area.”

The study was funded in part by the National Heart, Lung and Blood Institute and published Thursday in the journal Circulation Research.

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