Stem cells taken from mothers’ placentas could cure the damage caused by a heart attack, according to new research.
In experiments they boosted the failing organ when injected into mice, and scientists believe the same will happen in humans.
And the pioneering therapy may hold the key to regenerating other parts of the body – such as the kidneys or lungs.
Stem cells from women’s placentas could potentially treat more than than 23 million people living with heart failure worldwide
During a heart attack parts of the organ are killed off and not replaced so reversing this process is seen as the ‘Holy Grail’ of heart medicine.
Currently, people who have heart attacks are left with patches of scarring which last forever and can lead to heart failure and ultimately death.
Regenerative techniques using stem cells may provide a radical new approach – growing live, beating ‘heart patches.’
The placenta – a complex membrane found between a mother and her unborn child – is a rich source of stem cells.
They are also known as ‘master cells’ as they are capable of turning into any type of tissue – with the potential to treat a wide range of diseases in later life.
Now a study in lab rodents shows injections of certain placenta-derived cells – known as Cdx2 cells – repaired their hearts.
What’s more the cells have all the proteins of embryonic stem cells, which are known to generate all organs of the body, but also additional ones.
This gives them the ability to travel directly to the injury site, which is something embryonic stem cells cannot do.
They also seem to avoid the host immune response as the mice did not reject them when administered from the placenta to another animal.
This means stem cells from women’s placentas could potentially treat more than than 23 million people living with heart failure worldwide.
Dr Hina Chaudhry, director of cardiovascular regenerative medicine at Mount Sinai in New York, said: ‘These properties are critical to the development of a human stem cell treatment strategy, which we have embarked on, as this could be a promising therapy in humans.
‘We have been able to isolate Cdx2 cells from term human placentas also; therefore, we are now hopeful that we can design a better human stem cell treatment for the heart than we have seen in the past.
‘Past strategies tested in humans were not based on stem cell types that were actually shown to form heart cells, and use of embryonic stem cells for this goal is associated with ethics and feasibility concerns.
‘Placentas are routinely discarded around the world and thus almost a limitless source.’
At the moment, the only medical option for patients is a heart transplant but a lack of donor organs means most stay waiting for years.
Evidence is growing that stem cell therapy could provide the alternative.
Dr Chaudhry said: ‘Cdx2 cells have historically been thought to only generate the placenta in early embryonic development.
‘But never before were they shown to have the ability to regenerate other organs – which is why this is so exciting.’
Principal investigator Dr Chaudhry added: ‘These findings may also pave the way to regenerative therapy of other organs besides the heart.
‘They almost seem like a super-charged population of stem cells, in that they can target the site of an injury and travel directly to the injury through the circulatory system and are able to avoid rejection by the host immune system.’
Previous research by the same team found mouse stem cells went naturally from the placenta to the mother’s heart when it was damaged.
These turned into beating muscle cells called cardiomyocytes – beginning the repair process.
The latest study published in Proceedings of the National Academy of Sciences takes this a step further by identifying the specific Cdx2 cells that fueled it.
Dr Chaudhry said they comprised 40 percent of the placenta cells that travelled to the heart – by far the most.
To test their regenerative properties her team induced heart attacks in three groups of male mice.
One received Cdx2 stem cell treatments derived from mouse placentas after birth, another placenta cells that did not express Cdx2 and the third a saline solution that acted as a control.
The researchers devised a method to label and track the Cdx2 cells.
This showed they differentiated into beating cardiomyocytes, endothelial cells in the heart’s lining or smooth muscle cells.
Using MRI (magnetic resonance imaging) scans immediately after the heart attacks – and three months following therapy – all the animals given the cells improved significantly.
This included the regeneration of healthy tissue in the heart.
The stem cells had migrated directly to the heart injury and formed new blood vessels and beating heart muscle cells.
The mice injected with saline and the non-Cdx2 placenta cells went into heart failure and their hearts had no evidence of regeneration.
What’s more the Cdx2 cells have all the proteins of embryonic stem cells – which are known to generate all organs of the body – but also additional ones.
This gives them the ability to travel directly to the injury site – which is something embryonic stem cells cannot do.
They also seem to avoid the host immune response – meaning did not reject these cells when administered from the placenta to another animal.
First author Dr Sangeetha Vadakke-Madathil, a cardiologist at the Icahn School of Medicine, said: ‘These results were very surprising to us.
‘No other cell type tested in clinical trials of human heart disease were ever shown to become beating heart cells in petri dishes.
‘But these did and they knew exactly where to go when we injected them into the circulation.’
Within five years following an attack, half of patients will no longer be alive as eventually the organ becomes too weak to sustain sufficient blood flow.
Unlike some of our other organs the heart has a very limited ability to self-heal.
Heart muscle cells replicate at a rate of just 0.5 per cent a year – not sufficient to repair any significant damage.
Instead, the dead cells are replaced by thick layers of tough, rigid scar tissue, meaning that sections of the heart simply cease to function.
The most versatile stem cells come from embryos but, because harvesting these results in the destruction of the embryo, many scientists are investigating other sources.
Placentas provide a potential fresh source – and can be collected without any risk to babies.