Posted on 08/07/2010 12:53:27 AM PDT by neverdem
Cell biologists often seem like modern-day alchemists. Instead of turning lead or straw into gold, they're looking for ways to turn one kind of cell into another, potentially more useful, cell. Now, one research team has found a way to turn a very common heart cell into a cell missing in injured hearts.
A healthy heart is a mix of several kinds of cells, including cardiomyocytes, the muscle cells that beat, and cardiac fibroblasts, which provide structural support and help keep all the heart cells working together. When a mammalian heart is injured, for example by a heart attack, it forms scar tissue dominated by fibroblasts instead of cardiomyocytes. As a result, the heart doesn't fully recover its pumping capacity. Developmental biologist Deepak Srivastava and cardiovascular researcher Masaki Ieda of the Gladstone Institute of Cardiovascular Disease in San Francisco, California, and their colleagues wondered whether some cellular alchemy could prompt the fibroblasts to turn into cardiomyocytes.
The researchers used a technique called cellular reprogramming, which others had shown can turn one cell type into another. They inserted into mouse cardiac fibroblasts extra copies of more than a dozen genes known to play a role in heart development and watched to see whether any of the cells took on characteristics of cardiomyocytes. After several rounds of tests, the scientists identified a trio of genes that together did the trick. The team inserted extra copies of the three genes into cardiac fibroblasts growing in the lab, and after 2 weeks about 20% of them took on characteristics of cardiomyocytes, expressing typical genes for the muscle cells. After growing for a month, the reprogrammed cells began to contract, like beating heart cells, the researchers report in the 6 August issue of Cell. The reprogrammed cells look and act convincingly like bona fide cardiomyocytes, says Christine Mummery, a developmental biologist not involved with the research who studies cardiac stem cells at Leiden University Medical Center in the Netherlands.
Whether these cells could actually help repair a damaged heart remains an open question, however. Transplants of heart muscle cells created from embryonic stem cells haven't worked as hoped so far—the new cells don't seem to fully integrate into the heart tissue. Ideally, Srivastava says, researchers will find small molecules that can replace the three-gene cocktail. Such molecules could be applied directly to an injured heart and turn fibroblasts into cardiomyocytes. That might lead to more effective repair, he suggests. Mummery agrees. Reprogramming cells directly in the heart "would be potentially much more interesting" than transplantation, she says. The most important question now, she says, is whether the same alchemy will work on human heart cells.
The drugs could be loaded into a stent, a small tube used in coronary bypass operations.
IMHO, ignore that sentence in the next to last paragraph. Last I checked, stents are various tube-like devices used in revascularization procedures when coronary artery disease was limited to one or two coronary arteries to maintain their patency, i.e. unobstructed as in a tube. They are delivered by sophisticated catheters which already administered a dose of contrast agent into the coronary sinus which feeds the usually four main coronary arteries in order to see any significant narrowing of coronary arteries.
In the event of seeing three or four obstructed coronary arteries while obtaining what is called an angiogram, i.e. imaging of an artery, the cardiologist usually will decide that the patient needs bypasses around all of those arteries, typically with grafts from the patient's saphenous vein and/or mammary artery. That's why it's called a coronary artery bypass graft, CABG,(pronounced cabbage).
N.B. Coronary angiograms are rarely performed without good reasons. The catheter used in the procedure initially uses a femoral artery access before it's threaded back up into and through the aorta under flouroscopic guidance.
Any correctons are always appreciated.
regenerative medicine/stem cell ping
Emerging medical procedures and technology hav me in awe.
We have the most sophisticated medicine, impeded by the most primitive politicians.
To be really fair, it prolly should say sumfin like Trying To Turn Scar Tissue Into A Beating Heart. A solution may be readily located, or it may get no further than it has with the mice and petri dish cells.
Amazing stuff going on now. I met a guy a few years back who was fixing defective genes, then reinserting them into heart muscle cells. His work involved a specific kind of heart failure. Pretty wild.
Which is the reason we need to pay attention to the lack of funds now, for medical research..Great research is going on in big and small medical schools..You never know where answers will come from. I know, for a fact, that the politicians put earmarks and such ahead of this kind of funding. They totally ignore that medical scientists are to be lauded and supported, for all our sakes and many are dependent upon state funding.The University of South Florida, for example, has some very important research going on in the area of neurology which could be life saving for those suffering from neurological disease. I am sure these schools are surviving on what wealthy donors are able to give them. Didn't the federal government provide a grant for a "turtle crossing" down there somewhere? How much better it would have been to have given that money to medical research!
SAVE
Nature already does this. Not often, I’m told by my cardiologist, but occasionally.
I had a heart attack in 1989. It left me with a circular section of scar tissue on my heart that was not quite 2 inches in diameter. They monitored it via PET scans, angiograms and something called MUGAs for several years and by 1995 the scar tissue had been completely replaced by new viable beating muscle. After watching it for an another 2 years, the cardiologists declared my heart to be in pre-heart-attacked condition. My heart has repaired itself, new blood vessels feed the new tissue and the old clotted and damaged coronary blood vessels have atrophied back to virtual non-existence.
Has this been found to be a normal response or do you exercise regularly to build up your heart muscle (as opposed to sitting in front of the computer all day checking on new articles at Free Republic?). :)
30 minute walk each lunch hour, lots of red meat, and high cholesterol foods.
But I don’t think exercise or diet had anything to do with it. I think it’s just genes.
Exercise has been found to grow new collaterals that supply blood to the heart. I have had two CABG operations 10 yrs apart. Both times was told by the surgeons that my collaterals most likely saved my life since the regular arteries were so clogged. So as someone who basically was a couch potato (and computer addict) I now set aside time for a good walk everyday....and I do believe this is what saved me 3 yrs ago when having a heart attack (yes my body is a mess). My genes are bad so gotta find something to override that somewhat..for me it’s exercise............
I think it’s just genes.
From the viewpoint of genetics and possibly epigenetics your medical history makes you a person of great interest to researchers in regenerative medicine. A cardiac biopsy would be ideal, IMHO, but a blood sample or cotton swab from the inside of your cheek might do for now. I'm pretty sure folks at the Broad Institute and Howard Hughes Medical Institute, among others, would love to hear from you. They may make it worth your time.
If yor're interested in regenerative medicine, then check the NY Times article linked in comment# 1.
> A cardiac biopsy would be ideal, IMHO, but a blood sample or cotton swab from the inside of your cheek might do for now.
The cardiologist already did a biopsy telling me they needed to check on something.
Do you have any idea how much a biopsy hurts? It’s like someone ripping tissue from you with needle nose pliers.
I switched doctors after I finally figured out that I was just his lab rat.
For pain like you describe, I'd be damned if I didn't know the purpose of the biopsy and the results of the testing. I regret that you felt like "his lab rat." Would you consider seeing that doc again to find out what was learned? I'd be fascinated if you would do so and shared the results.
I would hope that the maximum amount of knowledge was gleaned from your pain. Those institutions that I mentioned, among others, might still be interested in other samples of your genes.
You could agree to a prompt autopsy for another cardiac specimen as part of your will, although I would stipulate that it would have to be for free at least. If some clown wants to charge your estate for it, I'd tell him to get lost. I only recall one autopsy during all of my training. Autopsies have become very rare.
Should I add you to my regenerative medicine/stem cell list?
Yes, please. I have been fascinated since learning that there was new blood vessel development in what was thought to be scar tissue 10 years after a relative had a major coronary. Often, if we can just give our bodies long enough and the strength to fight, they generally will heal on their own, but in some cases, that is not the case. I recall reading somewhere where the introduction of WBCs (?—iirc) into the spinal fluid led to the removal of scar tissue and at least a partial recovery.
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