Javascript is currently disabled in your web browser. For full site functionality, it is necessary to enable Javascript. In order to enable it, please see these instructions. 5 hours ago Previously, stem cells were thought to be organized in a strict hierarchy. In contrast, the new results show that the skin contains specialized stem cells holding a primary function, with the potential to change function if a need arises. This is illustrated in the figure, where the early stem cells were stained with a red protein a year before the pictures were taken. It shows that the stem cells maintain specialized functions as the skin develops and either forms the hair follicle, the fat gland or the barrier protecting us against environmental challenges. Credit: Kim Jensen, University of Copenhagen

All organs in our body rely on stem cells in order to maintain their function. The skin is our largest organ and forms a shield against the environment. New research results from BRIC, University of Copenhagen and Cambridge University, challenge current stem cell models and explains how the skin is maintained throughout life. The results have just been published in the recognized journal Cell Stem Cell.

New knowledge challenge stem cell models

The skin consists of many different cell types, including hair cells, fat- and sweat glands. It protects us against microbial and chemical attacks and forms a waterproof barrier that prevents fluid loss. Associate professor Kim Jensen' group from BRIC have through mapping of stem cell's behaviour in the skin found out that the skin uses a unique method to renew itself. Their results challenge the current perception of how our skin is renewed.

"Until now, the belief was that the skin's stem cells were organized in a strict hierarchy with a primitive stem cell type at the top of the hierarchy, and that this cell gave rise to all other cell types of the skin. However, our results show that there are differentiated levels of stem cells and that it is their close micro-environment that determines whether they make hair follicles, fat- or sweat glands, says Kim Jensen.

The new research from Kim Jensen completes the stem cell puzzle.

"Our data completes what is already known about the skin and its maintenance. Researchers have until now tried to fit their results into the old model for skin maintenance.

However, the results give much more meaning when we relate them to the new model that our research proposes, says Kim Jensen.

One such example is that it explains the current mystery of how skin cells can divide too much and initiate a skin cancer, without any traces of genetic change in the stem cells believed to maintain the outer layer of the skin. The research from the Jensen group may suggest that the reason that no changes can be found is, that these cells do not take part in the over-proliferation at all.

New knowledge of skin cancer and wound healing

Read more here:
Shining stem cells reveals how our skin is maintained

By Vignesh Ramachandran2013-08-15 20:20:34 UTC

Scientists in Pennsylvania have successfully transplanted human stem cells into a mouse's heart intentionally stripped of its own cells. The mouse heart began beating, showing the exciting potential for regenerative medicine.

The University of Pittsburgh School of Medicine said researchers first removed all the cells from the mouse's heart to prepare the heart as a "scaffold" on order to test regeneration. In technical terms, this process is called "decellularization." The researchers then repopulated the heart with human cells.

It took a few weeks for the mouse heart to rebuild, but in the end, the heart began contracting at 40 to 50 beats per minute, as explained in the video above. According to the Mayo Clinic, a normal resting heart rate for adults ranges from 60 to 100 beats per minute.

The university said it needs to do more work to make this type of regenerated heart "contract strongly enough to be able to pump blood effectively" and figure out how to make the heart correctly regulate its speed.

So, what does this mean for humans?

Heart disease is the leading cause of death in the United States and in the world. In fact, one person in the U.S. dies from heart disease every 34 seconds.

The Pittsburgh scientists say regenerative medicine could replace tissue for damage caused during a heart attack. Tissue engineering could also someday yield entire organs for patients.

One of our next goals is to see if its feasible to make a patch of human heart muscle, Lei Yang, an assistant professor of developmental biology at the Pitt School of Medicine, said in a news release. We could use patches to replace a region damaged by a heart attack. That might be easier to achieve because it wont require as many cells as a whole human-sized organ would.

The university said there is potential to take a skin biopsy from a patient in order to develop personalized, special cells that help regenerate a new organ. That replacement organ could someday be sustainable enough to transplant.

See the article here:
Human Stem Cells Revive Mouse's Cell-Stripped Heart

By Vignesh Ramachandran2013-08-15 20:20:34 UTC

Scientists in Pennsylvania have successfully transplanted human stem cells into a mouse's heart intentionally stripped of its own cells. The mouse heart began beating, showing the exciting potential for regenerative medicine.

The University of Pittsburgh School of Medicine said researchers first removed all the cells from the mouse's heart to prepare the heart as a "scaffold" on order to test regeneration. In technical terms, this process is called "decellularization." The researchers then repopulated the heart with human cells.

It took a few weeks for the mouse heart to rebuild, but in the end, the heart began contracting at 40 to 50 beats per minute, as explained in the video above. According to the Mayo Clinic, a normal resting heart rate for adults ranges from 60 to 100 beats per minute.

The university said it needs to do more work to make this type of regenerated heart "contract strongly enough to be able to pump blood effectively" and figure out how to make the heart correctly regulate its speed.

So, what does this mean for humans?

Heart disease is the leading cause of death in the United States and in the world. In fact, one person in the U.S. dies from heart disease every 34 seconds.

The Pittsburgh scientists say regenerative medicine could replace tissue for damage caused during a heart attack. Tissue engineering could also someday yield entire organs for patients.

One of our next goals is to see if its feasible to make a patch of human heart muscle, Lei Yang, an assistant professor of developmental biology at the Pitt School of Medicine, said in a news release. We could use patches to replace a region damaged by a heart attack. That might be easier to achieve because it wont require as many cells as a whole human-sized organ would.

The university said there is potential to take a skin biopsy from a patient in order to develop personalized, special cells that help regenerate a new organ. That replacement organ could someday be sustainable enough to transplant.

See the article here:
Human Stem Cells Revive Mouse's Cell-Stripped Heart

Scientists said Tuesday they had used stem cells to grow human heart tissue that contracted spontaneously in a petri dish -- marking progress in the quest to manufacture transplant organs.

A team from the University of Pittsburgh, Pennsylvania, used induced pluripotent stem (iPS) cells generated from human skin cells to create precursor heart cells called MCPs.

iPS cells are mature human cells "reprogrammed" into a versatile, primitive state from which they can be prompted to develop into any kind of cell of the body.

The primitive heart cells created in this way were attached to a mouse heart "scaffold" from which the researchers had removed all mouse heart cells, they wrote in the journal Nature Communications.

The scaffold is a network of non-living tissue composed of proteins and carbohydrates to which cells adhere and grow on.

Placed on the 3D scaffold, the precursor cells grew and developed into heart muscle, and after 20 days of blood supply the reconstructed mouse organ "began contracting again at the rate of 40 to 50 beats per minute," said a University of Pittsburgh statement.

"It is still far from making a whole human heart," added senior researcher Lei Yang.

Ways have to be found to make the heart contract strongly enough to pump blood effectively and to rebuild the heart's electrical conduction system.

"However, we provide a novel resource of cells -- iPS cell-derived MCPs -- for future heart tissue engineering," Yang told AFP by email.

"We hope our study would be used in the future to replace a piece of tissue damaged by a heart attack, or perhaps an entire organ, in patients with heart disease."

Read more:
Scientists use stem cells to grow human heart tissue

Public release date: 15-Aug-2013 [ | E-mail | Share ]

Contact: Katya Nasim katya.nasim@kcl.ac.uk 44-207-848-3840 King's College London

Researchers at King's College London have for the first time highlighted the natural regenerative capacity of a group of stem cells that reside in the heart. This new study shows that these cells are responsible for repairing and regenerating muscle tissue damaged by a heart attack which leads to heart failure.

The study, published today in the journal Cell, shows that if the stem cells are eliminated, the heart is unable to repair after damage. If the cardiac stem cells are replaced the heart repairs itself, leading to complete cellular, anatomical and functional heart recovery, with the heart returning to normal and pumping at a regular rate.

Also, if the cardiac stem cells are removed and re-injected, they naturally 'home' to and repair the damaged heart, a discovery that could lead to less-invasive treatments and even early prevention of heart failure in the future.

The study, funded by the European Commission Seventh Framework Programme (FP7), set out to establish the role of cardiac stem cells (eCSCs) by first removing the cells from the hearts of rodents with heart failure. This stopped regeneration and recovery of the heart, demonstrating the intrinsic regenerative capacity of these cells for repairing the heart in response to heart failure.

Heart failure when the heart is unable to pump blood around the body adequately affects more than 750,000 people in the UK, causing breathlessness and impeding daily activities. Current treatments are aimed at treating the underlying causes, such as coronary heart disease, heart attack and blood pressure through lifestyle changes, medicines and in severe cases, surgery. These treatments are sometimes successful in preventing or delaying heart failure. However, once heart failure develops the only curative treatment is heart transplantation.

By revealing this robust homing mechanism, which causes cardiac stem cells to home to and repair the heart's damaged muscle, the findings could lead to less invasive treatments or even preventative measures aimed at maintaining or increasing the activity of the heart's own cardiac stem cells.

Dr Georgina Ellison, the first author of the paper and Professor Bernardo Nadal-Ginard, the study's corresponding author, both from the Centre of Human & Aerospace Physiological Sciences and the Centre for Stem Cells and Regenerative Medicine at King's, said: 'In a healthy heart the quantity of cardiac stem cells is sufficient to repair muscle tissue in the heart. However, in damaged hearts many of these cells cannot multiply or produce new muscle tissue. In these cases it could be possible to replace the damaged cardiac stem cells or add new ones by growing them in the laboratory and administering them intravenously.'

Dr Ellison added: 'Understanding the role and potential of cardiac stems cells could pave the way for a variety of new ways to prevent and treat heart failure. These new approaches involve maintaining or increasing the activity of cardiac stem cells so that muscle tissue in the heart can be renewed with new heart cells, replacing old cells or those damaged by wear and tear.

Link:
Heart's own stem cells offer hope for new treatment of heart failure

Public release date: 15-Aug-2013 [ | E-mail | Share ]

Contact: Katya Nasim katya.nasim@kcl.ac.uk 44-207-848-3840 King's College London

Researchers at King's College London have for the first time highlighted the natural regenerative capacity of a group of stem cells that reside in the heart. This new study shows that these cells are responsible for repairing and regenerating muscle tissue damaged by a heart attack which leads to heart failure.

The study, published today in the journal Cell, shows that if the stem cells are eliminated, the heart is unable to repair after damage. If the cardiac stem cells are replaced the heart repairs itself, leading to complete cellular, anatomical and functional heart recovery, with the heart returning to normal and pumping at a regular rate.

Also, if the cardiac stem cells are removed and re-injected, they naturally 'home' to and repair the damaged heart, a discovery that could lead to less-invasive treatments and even early prevention of heart failure in the future.

The study, funded by the European Commission Seventh Framework Programme (FP7), set out to establish the role of cardiac stem cells (eCSCs) by first removing the cells from the hearts of rodents with heart failure. This stopped regeneration and recovery of the heart, demonstrating the intrinsic regenerative capacity of these cells for repairing the heart in response to heart failure.

Heart failure when the heart is unable to pump blood around the body adequately affects more than 750,000 people in the UK, causing breathlessness and impeding daily activities. Current treatments are aimed at treating the underlying causes, such as coronary heart disease, heart attack and blood pressure through lifestyle changes, medicines and in severe cases, surgery. These treatments are sometimes successful in preventing or delaying heart failure. However, once heart failure develops the only curative treatment is heart transplantation.

By revealing this robust homing mechanism, which causes cardiac stem cells to home to and repair the heart's damaged muscle, the findings could lead to less invasive treatments or even preventative measures aimed at maintaining or increasing the activity of the heart's own cardiac stem cells.

Dr Georgina Ellison, the first author of the paper and Professor Bernardo Nadal-Ginard, the study's corresponding author, both from the Centre of Human & Aerospace Physiological Sciences and the Centre for Stem Cells and Regenerative Medicine at King's, said: 'In a healthy heart the quantity of cardiac stem cells is sufficient to repair muscle tissue in the heart. However, in damaged hearts many of these cells cannot multiply or produce new muscle tissue. In these cases it could be possible to replace the damaged cardiac stem cells or add new ones by growing them in the laboratory and administering them intravenously.'

Dr Ellison added: 'Understanding the role and potential of cardiac stems cells could pave the way for a variety of new ways to prevent and treat heart failure. These new approaches involve maintaining or increasing the activity of cardiac stem cells so that muscle tissue in the heart can be renewed with new heart cells, replacing old cells or those damaged by wear and tear.

Link:
Heart's own stem cells offer hope for new treatment of heart failure