New biomaterial transplants bone-forming stem cells into severe bone fractures
It could reduce complications and infections from serious open fracture injuries
After creating new bone to fix a fracture the biomaterial is absorbed by the body
UK experts tested the material on mice and want to do clinical trials on humans
A new type of bandage has been developed that can rebuild broken bones by transplanting bone-forming proteins and stem cells directly onto fractures.
The biomaterial, which can be stuck to a fracture ‘like a plaster’ to accelerate healing, has been tested successfully on mice’s skulls.
After rebuilding bits of broken bone, the biodegradable bandage – which is two to three times the thickness of human hair – is absorbed by the body without any adverse side effects.
It is hoped that, following clinical trials, the ‘bone bandage’ could change how broken bones are treated in hospitals and reduce infections from serious open fracture injuries.
‘Our technology is the first to engineer a bone-like tissue from human bone stem cells in the lab within one week, and successfully transplant it in the bone defect to initiate and accelerate bone repair,’ said Dr Shukry Habib, from King’s College London.
‘The bandages are thin, and flexible, so they can be positioned and attached in a very minimally invasive way.’
Clinical trials are planned for the bone bandages and scientists plan to develop the concept further to improve healing in other organs and tissues.
‘The concept of the 3D-engineered tissue and the bandage has the potential to be developed to different injured tissues and organs,’ said Dr Habib.
The bandage itself is made from a polymer called polycaprolactone, which is already approved by the US Food and Drug Administration for use in medicine and dentistry.
The team have developed two types of bandage that both improve bone repair – both with and without stem cells.
The biomaterial is coated in a protein called ‘Wnt3a’ that is used throughout the body for growth and repair
‘Wnt3a is part of a family of similar proteins that are found all over the body, and are involved in the growth and repair of many organs and tissues,’ Dr Habib told MailOnline.
‘In the biomaterial bandage alone, new bone is grown directly underneath when the bandage is attached over the top.’
In the second version, which is even more effective, human stem cells from bone marrow are grown in a 3D gel before transplantation, which form layers of cells similar to the cells found in bone.
‘The Wnt-bandage alone doubles bone repair, and the addition of extra human stem and bone cells on the Wnt-bandage triples bone repair compared to without treatment over the same healing time,’ Dr Habib said.
Stem cells have the unique ability to develop into specialised cell types in the body, including bone-like tissue.
The Wnt proteins pass signals into the stem cells through cell surface receptors to promote long-term self-renewal.
This bandage can be stuck to a bone fracture like a plaster and enhance the bone’s natural ability to heal.
Experiments proved that the newly formed bone-like tissue – consisting of human and mice cells and created in one week – is structurally comparable to mature bone.
After eight weeks of being attached to the lab mice, X-ray micro-computed tomography images showed reconstructed bone in the calvaria, the top part of the skull.
Biomaterial bandages could make a difference in recovery times for patients with serious bone fractures, the team say.
Healing a serious fracture can be slow or can even fail in vulnerable patients such as the elderly or those with underlying health conditions.
Current methods to repair bone include using synthetic implants or donor tissue, where bone is taken from elsewhere in the body.
But these methods rely on the body’s own capability to heal, which can be weakened after serious injury.
‘Bone defects often require substantial donor bone tissue and represent a burden for patients and healthcare systems,’ the experts say.
‘Understanding the mechanisms that regulate human skeletal stem cell function is crucial for overcoming this issue.’
Some current cell-based therapies grow additional cells and introduce them to the fracture.
However, the implanted cells in existing technologies often die and lack long-term support of the healing bone.
As an alternative, this ‘bone-like bandage’ supports the survival and bone-forming ability of these extra stem and bone cells throughout the healing process.
It also specifically targets the fracture and does not leak to the healthy tissue.
The study has been published in Nature Materials.
WHAT ARE STEM CELLS?
Stem cells are special human cells that have the ability to develop into many different cell types, from muscle cells to brain cells.
In some cases, they also have the ability to repair damaged tissues.
Stem cells are divided into two main forms – embryonic stem cells and adult stem cells.
Embryonic stem cells can become all cell types of the body because they are pluripotent – they can give rise to many different cell types.
Adult stem cells are found in most adult tissues, such as bone marrow or fat but have a more limited ability to give rise to various cells of the body.
Meanwhile, induced pluripotent stem cells (iPSCs) are adult cells that have been genetically reprogrammed to be more like embryonic stem cells.
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