Scientists regenerate heart muscle in primates

In a major advance, researchers at the University of Washington have successfully restored damaged heart muscle of monkeys using heart cells created from human embryonic stem cells.

The results of the experiment appear in the April 30 advanced online edition of the journalNature in a paper titled, “Human embryonic-stem cell derived cardiomyocytes regenerate non-human primate hearts.”

See a copy of the paper.

The findings suggest that the approach should be feasible in humans, the researchers said.

“Before this study, it was not known if it is possible to produce sufficient numbers of these cells and successfully use them to remuscularize damaged hearts in a large animal whose heart size and physiology is similar to that of the human heart,” said Dr. Charles Murry, UW professor of pathology, bioengineering and medicine, Division of Cardiology, who led the research team that conducted the experiment.  A physician/scientist, Murry directs the UW Center for Cardiovascular Biology and is a UW Medicine pathologist. He holds the UW Arra and Eva Woods Endowed Professorship.

Murry said he expected the approach will be ready for clinical trials in humans within four years.

In the study, Murry, along with Dr. Michael Laflamme and other colleagues at the UW Institute for Stem Cell & Regenerative Medicine, experimentally induced controlled myocardial infarctions, a form of heart attack, in anesthetized pigtail macaques.

The infarcts were created by blocking the coronary artery of macaque for 90 minutes, an established model for the study of myocardial infarction in primates.

In humans, myocardial infarctions are typically caused by coronary artery disease. The resulting lack of adequate blood flow can damage heart muscle and other tissues by depriving them of oxygen. Because the infarcted heart muscle does not grow back, myocardial infarction leaves the heart less able to pump blood and often leads to heart failure, a leading cause of cardiovascular death.

The goal of stem cell therapy is to replace the damaged tissue with new heart cells and restore the failing heart to normal function.

Two weeks after the experimental myocardial infarctions, the Seattle researchers injected 1 billion heart muscle cells derived from human embryonic stem cells, called human embryonic stem cell-derived cardiomyocytes, into the infarcted muscle. This was ten times more of these types of cells than researchers have ever been able to generate before.

All the monkeys had been put on immunosuppressive therapy to prevent rejection of the transplanted human cells.

The researchers found that over subsequent weeks, the stem-cell derived heart muscle cells infiltrated into the damaged heart tissue, then matured, assembled into muscle fibers and began to beat in synchrony with the macaque heart cells. After three months, the cells appear to have fully integrated into the macaque heart muscle.

On average the transplanted stem cells regenerated 40 percent of the damaged heart tissue, said Laflamme, UW assistant professor of pathology, whose team was principally responsible for generating the replacement heart muscle cells.

The results show we can now produce the number of cells needed for human therapy and get formation of new heart muscle on a scale that is relevant to improving the function of the human heart,” Laflamme said.

Ultrasound studies of the macaques’ hearts showed that the ejection fraction, an indication of the hearts ability to pump blood, improved in some of the treated animals but not all. The researchers also found that arteries and veins from the macaques’ hearts grew into the new heart tissue, the first time it has been shown that blood vessels from a host animal will grow into and nurture a large stem-cell derived graft of this type.

The most concerning complications were episodes of irregular heartbeats, or arrhythmias, that occurred in the weeks after the macaques received the stem cell injections, Murry said. None of the macaques, however, appeared to have symptoms during these episodes, which disappeared after two to three weeks as the stem cells matured and became more electrically stable.

Going forward the UW researchers will work to reduce the risk of arrhythmias, perhaps by using more electrically mature stem cells. They also will try to demonstrate definitively that the stem cells are actually strengthening the heart’s pumping power.

These cells have improved the mechanical function in every other species in which they have been tested, so we are optimistic they will do so in this model as well,” Murry said.

The material in this press release comes from the originating research organization. Content may be edited for style and length. Have a question? Let us know.


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25 thoughts on “Scientists regenerate heart muscle in primates”

  1. Has it being proven to can work without any side effects and causing any harm to human beings. If it can then this shows how closely related we are to monkeys, its just that speciation was well advantageous to us. Te question i’m asking is then are we going to kill the monkeys and remove their hearts to make human with heart problems live………….isn’t that cruel to animals?

  2. I have always been fascinated by stem cell research and all it’s various implications. The ability to grow new tissue and organ will allow for a new peak in modern medical treatment. But this may also give rise to more people who go against doctors and medication, saying that they do not have the right to play god and that with this technology, will be able to create whole human bodies which will also produce the question whether they have souls or not. And could criminals produce new eyes, fingerprints, faces, IDENTITIES.
    Stem cell research has come along way and may be able to help all living organisms, not just humans but i believe much must still be considered with regards to safety management.
    I for one can not wait for they day we will be able to just print out new organs. If that will be possible???

  3. “Wow!”-The first word that comes to mind as read this article.Sounds like something out op a sci-fi film.Whats next? A cure for aging? Even with all this progress concerning stemcell research long term side-effects and consequences are still very uncertain.More research sould definitly be done.Let us also not forget about the few of us against stemcell research for moral reasons.None the less this is revolutionary work which all of us will hopefully benefit from in the future.

  4. i like the fact that technology and science meet. but i agree with most of my fellow bloggers this is truly scary, that one can create new organs and so on from stem cells. only problem i see is that this will only be for the extremely wealthy people and those less fortunate or in dire need for organs will not be able to get them…..

  5. This is very exciting news as this could change the face of cardiology dramatically in the near future if we can only improve it to such a point as to implement it in the treatment of patients with minimal side effects. What would be interesting is to know how long this intervention lasts and how effective it really is in improving a patients situation as well as to how far it can reach in regards to which conditions can be treated with this new procedure.

  6. With the same purpose of producing new organs to replace damaged/diseased/non-functional organs , this process could also take place outside of the body of a living organism . In biomedical labs , stem cells which is taken from a healthy organism’s organ of the same sort as the one which has to be produced , is treated with a substance which stimulates cell devision . After the cell treatment process , the treated cells is placed on a silicone shape of the organ , manufactured by machines to act as a basic structure on which the new cells can divide and grow to , under the right conditions ( temperature etcetera) to form an organ as the one needed . The newly formed organ could then be planted into a living organism . An example of this process is an ear , produced with stem cells and a silicone structure of an ear in a lab , which is then placed in the location where the missing / lost ear is supposed to be . The silicone structure could also be replaced with an actual organ , similar to the one needed ( when human organs is to be produced, the organ acting as structure for the new cells is often taken from a pig) from which the organism from which the organ originates’s cells have been removed and only the organ structure (skeleton) remains . An example of this is a heart valve taken from a pig , used as structure for new human cells to grow on , which is then placed in the organism which needs the organs ( whose stem cells have been placed on the organ structure to divide ) .
    Thank you
    David van der Merwe

  7. This kind of research can revolutionize the world of medicine and medical studies.This research found that human embryonic stem cells could not only repair damaged heart tissue but it could possibly strengthen the heart’s pumping power. The medical applications that this could lead to are endless. For example, as mentioned by other comments, these findings could aid in the research of repairing other damaged organs or the repair of cells damaged by chemotherapy.
    Although, research of this nature always poses the question of whether or not it is ethical to perform these kinds of tests on animals. In my opinion, as long as the tests are done in a humane way and the animals are not intentionally harmed, then the research is ethical.
    I am excited to see what future research of this nature could yield. The possibilities are endless and who knows perhaps this kind of research could even lead to the complete repair of organs or even growing new, functioning organs from scratch.

  8. I think this is a huge step forward for modern medicine. Although the use of stem cells have brought on some controversy in recent years, it is undeniable that the use thereof has opened up a wide range of possibilities in regards to the treatment of various conditions that was previously incurable. As mentioned in the article, there are still some complications, such as arrhythmia, but it is understandable since it is still in the early stages of research. The myocardial infarction (necrosis of the heart muscle) prevents the heart muscle from regenerating, but this procedure can provide is with a cure, should it be proven successful in humans.

  9. This is an interesting article, what happens next? in future will every person be able to “cultivate” his/her own organs? will dis new discovery enable us humans to have a longer lifespan ?

    What happened to the primates after this experiment was deemed successful?

  10. It is fascinating how stem cell research is making such astronomical breakthroughs in medicine. I understand that it is necessary to use animals in these experiments in the name of science and medical advancement, but it is an incredible shame that such cruelty is necessary. That aside, would it be possible to develop similar procedures for central nervous system injuries or for other damaged major organs?

  11. It is amazing to see how far science has come. Imagine all the possibilities! This research could be the start of something enormous.

    In the old days people lived much longer than in the new era we live in. With this we could also live longer. It would be even better if these cells could work for all organs in the body, like replacing the cells that was damaged during the treatment of cancer with chemotherapy.

    One thing that seems inhumane though is the thought of hurting animals to test a theory. Although no animals were hurt during these trials, what proof did they have to rectify these tests? If these animals were in any danger, would they still be doing trials on them?

    Looking at the bright side, the negative effects such as arrhythmia did not do any harm and the trials is going fluently so far. If this could help people in the future without harming animals, it cannot be too bad to do tests on them. This research could be the answer to a lot of medical problems.

  12. We have a time where science and technology has progressed to such a great extent that there is no problem to which we cannot find a solution.

    Tissue culture and stem cell research were aspects of science which we were taught at school. I found these sciences very interesting, because we can use our own body cells to regenerate the body cells which were damaged. Reading this article made me think about what science cannot do today.

    It is amazing how scientists can use human stem cells to regenerate heart muscle in other primates. Yes, this surely is a time in our lives where scientists have come a little close to replicating the doings of God Almighty. However, we should always heed the fact that scientists are also humans, so they also err, but God is God, so can never err. Life and death comes from God.

  13. One word, revolutionary. That is all that came to mind when I read this article. To be honest I didn’t know how advanced stem cells had become. I still remember the days when stem cell research was simply a hypothesis, an idea that was researched and talked about in the science community. Now, it is no longer just research, instead it is a possible solution to many of the world’s heart problems. The fact that human embryonic stem cells were used in the primates does not surprise me, due to the fact humans and primates are so closely related to each other.

    I appreciate the fact that the primates were treated in some what of a humane way, that they were anesthetized during their induced heart attack. (I am very much against animal cruelty). They have made a great contribution to understanding and advancement to the use of stem cells.

    But, why should it just be the heart that gets fixed, as most of us know stem cells differentiate into useful cells, so why can’t a study be done on some of the other organs to see if they can be repaired in a similar fashion to the heart? As someone stated before, cancer patients would need new cells to replace those that were killed during chemotherapy, can stem cells be a viable solution?

    One thing that I would like to suggest is that there be some statistics in the article. Statistics like, what was the survival rate? Depending on the amount of damage, what was the chance of survival after the use of stem cells, is it high or low?

    Then one last thing, I know it will take about four years until the human trials begin, but, will anyone be able to go through the procedure or will there be factors that can prevent a person from being able to do it?

  14. What fascinates me most about this article is that the human embryonic stem cells were able to differentiate into cells that the macaques could make use of. I do understand that there were drugs given to reduce the risks of rejection, however, the mere thought that this was a success is quite amazing. The possibilities of being able to repair organs from stem cells are becoming a far greater reality. It also raises the questions as to whether human embryonic stem cells need to be made use of.
    Currently there are many successful trials of inducing pluripotency in stem cells, which in theory should provide an alternative option to using embryonic stem cells. This may be something worth investigating further in terms of this study considering the ethical arguments surrounding the use of human embryonic stem cells. These arguments may even be made greater as the cells are being used for macaques and not humans.
    I believe that as long as these ethical issues are addressed, as well as adequate protection of the animal testing is done, this study will prove a great success for future heart and organ repairs.

  15. This article proves the extent to which some experiments are carried out just to find ways to improve the human race’s life expectancy. The importance of the macaques heart muscles accepting the heart stem cells just proves how far we have come in terms of biotechnology and just how far we still can go. This research could be used to regenerate almost any organ and hopefully it won’t be limited to only benefiting humans. The regeneration of cells might even be incorporated into the treatment of cancer patience, especially for the recovery after chemotherapy.

  16. I have to admit, I am in total awe of how far our race has come. I mean to think we were once “dumbfounded’ by the idea of fire…wow
    As much as I am amazed by the possibilities provided by this research, I am also fearful of what comes with those possibilities. Don’t get me wrong, the idea of not having to wait for another person’s demise to get a chance in life yourself is fantastic but the possibility of us ,mere mortals, playing ‘god’ is quite a frightening thought{“_}

  17. The science behind the article is indeed interesting and facinating,1 would never think muscles can be repaired,but it looks like the science and technology is going beyond God’s creativity and can lead to people being cloned.

  18. When reading this article, it is truly incredible to see that stem cell research has come this far. It is startling at first when you realize that animals have to suffer for the benefit of mankind, but seeing that it is the only way to tell if the cells are capable of performing their function in an organism, there is no other choice. The infarctions are the only way to test the outcome! Stem cell research may be questioned by the non-scientific community, but the use of embryonic stem cells does not pose any danger to the embryo, due to the replacement of the cell by cell division. Therefore I am not against using them in medical research.

    The growth of the amount of stem cell-derived cardiomyocytes is an achievement on its own. Considering that the heart of the macaque was able to grow arteries and veins to sustain the new heart muscle tissue and the successful integration of these cells was extraordinary. Even when considering the complications during the maturation period of the cells in the heart, the future possibilities cannot be overlooked. This is just one step forward in being able to regrow a human heart from stem cells, without the hassle to get a suitable organ donor. In contrast, this same research may be possible in the regrowth of skeletal muscles in humans who have suffered injury, or even for the study in muscle dystrophy. Although, seeing that some specimens did not show improvement, further studies will need to be performed before considering it for human trials.

  19. This discovery can lead to a great amount of new advances. If the procedure is ready for human testing within 4 years we might have an even better understanding of the heart and diseases related to the heart. This might also lead to other studies of cell regeneration and could possibly lead to people regenerating lost limbs in the future. I know there is a lot of potential in this research field.

  20. This is absolutely remarkable! The sheer thought that scientists are now able to generate heart cells from healthy embryonic stem cells in order to restore those cells that have been damaged due to lack of oxygen caused by coronary artery disease. This has really intrigued me to finding out more on how these newly generated cells are created and the process it under goes in order to infiltrate the damaged area, thus maturing and becoming apart of the organ. This truly opens your eyes and shows you just how amazing our body is.

    Although I am not entirely for the testing of animals and purposefully causing damage to the tissue in order to test whether or not these healthy human stem cells would be beneficial in restructuring the injured tissue, it has given us a greater insight into the possibilities of fixing the damaged tissue to prevent heart failure and possible cardiovascular death. Even though further testing needs to be done to limit certain side affects it is still with out a doubt a truly remarkable discovery and will be crucial in decreasing mortality rates caused by heart failure.

  21. The current breakthroughs in cardiac disease research are really mind boggling .The mere fact that Human embryonic cells could regenerate a primate heart is an achievement.

    This study could hold the key to allowing people with cardiac damage a better life. The Human will to survive has fuelled our existence for years.Yes some might say we have reached a new level of playing God, however the will to survive is the major factor.This cardiac research finding will reignite the flame of hope for people with damaged hearts.

  22. This is a truly immaculate field of study as stem cells has the significant possibility to evolve into several divergent cell types within the human body amid early life and growth. In extension, in several tissues they serve as a subjective repair scheme, dividing substantially without restraining to restore other cells as long as the organism is alive. Therefore, when a stem cells segregates, each new cell has the possibility either to continue being a stem cell or become another type of cell with a more functional duty.

    Regarding this field of study there would generally be a contrasting point of view. Firstly, there would be a view that supports the study of stem cell research when viewing it from a science point of view. As a result of looking at the research from a science point of view, it is regard as an advance in the science field and towards perfecting what “needs” to be perfected.

    Secondly, an opinion of scientists being regarded as playing “God” also comes to light, as non scientists would regard this as trying to change what God has already created in a perfect sense.

    Although, as a science student myself i regard this as something remarkable, as i personally feel that God gave us the knowledge to be able to discover, create and perfect what can be perfected, created or discovered.

    I look forward to observing the research and results of these experiments, and observing how we change and improve lives by the new stem cells research.

  23. The study conducted shows promising evidence that there is a possibility to remuscularize damaged heart muscles. This presents the opportunity to correct any damage already done and prevent any further damage to one of the, if not the most important organs in the human body. If the damage can be prevented in the early stages and corrected effectively the risk of heart failure can be minimized if not eliminated completely.

    Use of stem cells also presents opportunities in personalizing medicine. Harvesting stem cells from a patient, specializing them in a perti dish to a specific task or organ and then re-injecting them into the same patient minimizes the risk of rejection and any other complications that may arise from the treatment.

    This discovery however poses another question. Is it ethical ? Are scientists using ethical possesses and procedures to test their theories ? Is it ethical of us to take stem cells and specialize them to the task we want them fulfill to instead of the body using them as is needed naturally ?

  24. I find this simply amazing! It is absolutely fascinating what science is capable of doing, even if it is a little bit scary. If we are able to repair heart tissue, who knows what else science is capable of doing?
    However, I don’t think inducing infarctions on helpless animals is humane, even if it was for the greater good of science. It was a good thing the macaques’ survived.
    It would be great to know how the macaques are doing now, after the two to three weeks as stated in the article. Are there any more irregular heartbeat episodes? Are they healthy?
    All-in-all, this was an interesting article.

  25. Wow it is quite interesting to here that the time is almost upon us where we can start to replace organs in our body with out the need to find a suitable organ donor.

    What has surprised me, is the fact that they have used human embryonic stem cells to help repair a macaque’s damaged heart. No wonder there were a few irregular heart beats in the first few weeks. I have heard that they are using stem cells in laboratories all over to reproduce organs of different kinds of animals, the one story is, they claim to have been able to grow a pig’s heart through what they call cell culture. Using this technique could they use human embryonic stem cells to not only repair major organs, as well as regrow them in laboratories but also use the stem cells to help grow limbs for people because so far all the stem cells have been able tor repair is heart tissue, which is just muscle and blood vessels, but would they be able to grow or repair an arm or a leg?

    The thing that i disagree on is the tests that they have had to do on the macaques, they literally gave the monkeys heart attacks just to see if our stem cell can be used to repair damaged muscle.

    Good article a very interesting read, it a little scary that we are almost beginning to play god when it comes to being able to repair ourselves.


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