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Arthritis is a common and painful disease caused by damage to the joints. Normally, cartilage pads cushion these points. But the injury or age can wear them down. As the cartilage deteriorates, the bone begins to hit the bone and everyday activities, such as walking, become excruciatingly painful.
Currently the best available treatments attempt to replace the damaged cartilage with a healthy piece taken from another part of the body or from a donor. But the amount of healthy cartilage it is limited. If it is your own, transplanting it could damage the place from which it was obtained; if it’s from someone else, your immune system will likely reject it.
Therefore, the best possible treatment would be regenerate healthy cartilage in the damaged joint itself.
Some researchers have tried to amplify chemical growth factors to induce the body to develop cartilage on its own; other attempts rely on a bioengineered scaffold to give the body a template for fresh tissue. But none of these approaches work, not even in combination.
«The regenerated cartilage does not behave like the native cartilage. It breaks, under normal joint stresses, “says UConn bioengineer Thanh Nguyen, author of the study published today.
«Science Translational Medicine»
Nguyen’s lab has been working on cartilage regeneration and they have found that electrical signals are key for normal growth.
They first designed a tissue scaffold made from acid nanofibers poly-L lactic (PLLA), a biodegradable polymer that is often used to stitch surgical wounds.
Said nanomaterial has a property called piezoelectricity. Thus, when pressed, it produces a small burst of electrical current.
In this way, they explain, the regular movement of a joint, such as that of a person walking, can cause the PLLA scaffold to generate a weak but constant electric field that encourages cells to colonize it and turn into cartilage.
With this alternative, no external growth factors or stem cells (which are potentially toxic or have a risk of unwanted adverse events) are needed and, more importantly, the cartilage that grows is mechanically robust.
The team tested their system on the knee of an injured rabbit. The rabbit was allowed to get on a treadmill for exercise after the scaffold was implanted and, as predicted, the cartilage grew back normally.
“The piezoelectricidad it is a phenomenon that also exists in the human body. Bones, cartilage, collagen, DNA, and various proteins have a piezoelectric response.
Our approach to cartilage healing has great clinical translation and we will study the related healing mechanism, ”said Yang Liu, lead author of the published work.
The results are exciting, but Nguyen prefers to be cautious.
“This is a fascinating result, but we need to test it on a larger animal, one that is closer in size and weight to a human,” says Nguyen.
Your lab would like to observe the treated animals for at least a year, probably two, to make sure the cartilage is durable. And it would be ideal to test PLLA scaffolds on larger animals as well.
Arthritis is a disease typical of old age in humans. The animals young are more easily cured than old: If piezoelectric scaffolding also helps older animals heal, it could be a breakthrough in the field of bioengineering.
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