Every year thousands of patients die while waiting for an organ transplant. Whilst the number of organ donors continues to rise as more is done to bring awareness of the situation to the public conscious, there still aren’t enough organs to go around. People with diseased organs and those with spinal cord injuries face a life of inactivity and pain.
But what if we didn’t need to wait for someone to donate an organ? What if we could build new tissues and new organs, meaning a constant supply of spare body parts to replace those that are injured or damaged?
Well that is exactly what tissue engineering and regenerative medicine aims to do. Dr. Jay Vacanti is widely credited for pioneering this breakthrough technology after watching too many children die of liver failure, whilst waiting for a transplant.
He wanted to find a way to regenerate liver tissue and so he teamed up with a lab at MIT and set about implanting a polymer scaffold filled with liver cells into rats with liver diseases – the rats were able to grow new (functioning) liver tissue within weeks.
What is tissue engineering?
Tissue engineering (as a concept) was officially brought into fruition in 1988 at a National Science Foundation workshop as a way to represent a new field in science that was focusing on regenerating human tissues, both portions of tissue and whole tissues.
Tissues are engineered via a combination of cells, scaffolding, various biomaterials and growth factors.
The term tissue engineering is used interchangeably with the term regenerative medicine, as both produce tissues (albeit regenerative medicine does it through the use of stem cells).
Why is tissue engineering important?
Tissue engineering is fast becoming a market with huge potential, addressing specific medical needs such as organ failure or major tissue damage.
The goal of tissue engineering is to create functioning tissues that enable the restoration, maintenance or improvement of damaged organs or tissues. Tissue engineering allows for the treatment of diseases and illnesses that would otherwise incapacitate or claim the life of the patient. It enables tissue regeneration where evolution prohibits natural regeneration. In short, tissue engineering allows the body to heal itself.
Whilst it sounds relatively straight forward in theory, tissue engineering research, despite significant investment in recent years resulting in huge leaps forward, has achieved very little commercial success. But that’s not to say that we should give up on it, not at all.
The potential for its application are too vast and the prospect that we could address medical conditions for which there currently stands no existing (successful) therapy is huge.
How do tissue engineering and regenerative medicine work?
Tissue engineering and regenerative medicine are similar in theory, but different in practice. Both result in the creation of new tissues, however tissue engineering involves building new tissues, whereas regenerative medicine relies on harnessing the body’s natural ability to self heal in order to restore function to damaged tissue and organs through the use of stem cells.
Whilst scientists have long grown cell cultures in petri dishes, these lumps of cells have proven useless at serving any functional purpose when implanted into the human body.
What is required is a scaffold that can support and help form new tissue growth. Scaffolds for tissue engineering are made from biodegradable (and biocompatible) polymers that can accommodate and assist the cells used in engineering new tissues.
Seeded onto these scaffolds are cells that have been grown in a lab. These cells are stem cells, the building blocks of all tissues. The cell-seeded scaffold is then coated in a material that encourages the stem cells to grow and multiple, and as they do so, they no longer require the scaffolding, which in time breaks down and is absorbed into the new tissue.
Current applications of tissue engineering in biomedicine
Currently tissue engineering only plays a small role in biomedicine, providing supplemental bladders, or small arteries or skin grafts when required. A full trachea has even been grown and implanted. But the use of tissue engineering remains in its infancy and is extremely costly.
Whilst livers, lungs and hearts have been grown (successfully) in labs, scientists are still a long way from being ready to implant lab grown organs into patients. But that doesn’t mean they’re a waste of time. Far from it.
The lab grown tissues have proven to be incredibly beneficial to developing and trialling new drugs, as actual human tissue enables scientists to see how the drug might react without endangering anyone’s life and reducing the number of animals that are tested on and used in research.
Future of tissue engineering
The future of tissue engineering is filled with promise and potential. This constantly evolving market is estimated to grow to $17 billion by 2023, a huge increase from $7 billion in 2016.
So just what does the future of tissue engineering hold?
- The ability to deliver outcomes more successfully than conventional therapies
- The removal of organ rejection as new organs are grown with the patient’s own cells
- The elimination of organ donation all together
- A reduction in the number of medicines a patient needs to take after organ transplants
- A reduction in the risk of complication following transplant surgery
- The lowering of the number of follow up appointments needed and thereby easing the burden on the health care service
Dr. Rob Buckle, UKRMP Director and MRC Chief Science Officer, called regenerative medicine a ‘cure for tomorrow’ and we couldn’t agree more.