A protein found at high levels in the blood of young mice has been shown to reverse the effects of heart failure in older mice, according to a paper published by researchers from the Harvard Stem Cell Institute in Cell this week.
The team of researchers, led by Richard Lee and Amy Wagers, hope that the protein responsible for the effect, Growth Development Factor 11 (GDF11), may also be the key to reversing heart failure in humans.
The condition occurs when the heart is unable to pump sufficient blood to meet the demands of the body. It is most often seen in the elderly, affecting 1% of those aged over 50, and 5% of those aged 75 and above.
It is broadly divided into two types – systolic and diastolic heart failure. In systolic heart failure, the heart loses its ability to squeeze blood out of the heart as effectively as it should. In diastolic heart failure, the heart becomes stiffer as it ages, losing its ability to relax and fill up with enough blood needed to be pumped to the rest of the body.
Driven by the idea that a component in young blood could reverse this stiffening effect, the researchers circulated blood from young mice in old mice with diastolic heart failure. Given this treatment, they found that the hearts of their older mice became less stiff, resembling the more normal, healthy hearts found in younger mice.
Analisying the different components present in the blood of young and old mice revealed that the GDF 11 protein levels were much higher in the young blood. To confirm that this protein was responsible for the therapeutic effect, the researchers administered older mice with laboratory-made GDF11, which showed similar results.
"GDF 11 is a protein known to be useful in developing foetuses as it gives tissues instructions on how to grow. (However) There wasn’t much known about what it did in the adult organism before these studies," says Dr Lee. "We believe that GDF11 is a protein hormone that circulates in the blood of young mice and maintains the heart at a healthy state. When GDF 11 falls down (as) the mouse ages, the hearts appear to age."
The team in Boston have created quite a stir with their research as this could be the key to not just curbing the development of diastolic heart failure in the elderly but also in reversing the effects of those already with the disease.
"We do know the protein can be found in human blood but we don’t know its relationship to human ageing, or to the diseases of human ageing,” explains Lee. "The next step will be developing the blood tests for humans, and then we will be able to measure the levels of this hormone in human samples. That will tell us whether the levels of this hormone will be causing or at least correlating with human diseases of ageing."
And because GDF 11 has also been found to have effects on other organs in the body too, Lee and colleagues now need to look at what other organs it might be able to rejuvenate...
Listen here to the Interview with Dr. Richard Lee