Scientists from Melbourne University have engineered a fast and scalable approach to making blood vessels using natural tissues.
The research team applied a novel approach to tissue engineering of blood vessels led by Redmond Barry Distinguished Professor Andrea O’Connor and Associate Professor Daniel Heath, both of whom are from the Department of Biomedical Engineering at Melbourne University, Australia.
The new method for creating blood vessels uses complex geometries, which resemble the native blood vessels, using a combination of fabrication technologies and numerous materials.
Mr. Heath explained that for many years now, scientists around the globe have tried to master blood vessel tissue engineering.
“
Current methods are slow, require specialised and expensive equipment like bioreactors, and are low throughput—meaning it’s difficult to provide the needed supply of engineered vessels,” said Mr. Heath
“By combining multiple materials and fabrication technologies, our method brings us closer to a future where engineered blood vessels will become a transformative solution for cardiovascular disease, especially for those patients who lack suitable donor vessels.”
Blood vessels fulfil a crucial role in the human body as they are the carriers of rich oxygenated blood and key nutrients throughout the body, as well as transporting out toxic waste.
Dysfunctions and illnesses associated with blood vessels are considered as serious and life-threatening, often resulting in strokes, heart attacks, etc., which according to the
World Health Organisation, are the leading cause of death globally, resulting in 17.9 million deaths globally each year.
“The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use and harmful use of alcohol. The effects of behavioural risk factors may show up in individuals as raised blood pressure, raised blood glucose, raised blood lipids, and overweight and obesity,” the WHO says.
What Was Researched
When blood vessels are severely damaged, usually, bypass surgery is used to replace them. However, this has its limitations, especially when it comes to blood channels like the coronary artery, which has a very small diameter. The alternative, in this case, then is to use a graft that is made of synthetic, non-living materials, but they can lead to blood clotting and blockages, thus they are not regarded as always safe to use.This makes the situation difficult for patients, leaving them with limited options after such surgeries or when they suffer from diabetes, for example.
Considering these limitations, scientists explored the option of introducing ‘tissue-engineered’ blood vessels, which are made of human tissues and cells, called ‘tissue-engineered vascular grafts’ or TEVGs.
As they specify in their
paper, the TEVGs showed mechanical properties that are similar to the native blood cells, thus, this new approach represents a significant step forward in the tissue engineering field.
This new approach is not only more natural, but it allows for the reproduction of key native blood cell structures within hours, which makes this method both accessible and scalable.
Thus Ms. O’Conner thinks that this research is a step in the right direction in the field of human blood cell engineering.
“We are now able to rapidly and cheaply manufacture blood vessels using living tissue that has appropriate mechanical properties and mimics the cellular orientation of the inner-most layer of blood vessels,”
said Ms. O’Connor.
“While the engineered blood vessels are not yet ready for bypass surgery, the findings mark a significant advancement in the field of tissue engineering.”
What Are Engineered Blood Vessels
Engineered blood vessels, also known as artificial blood vessels, tissue-engineered blood vessels, or tissue-engineered vascular grafts (TEVGs), are designed and created in a laboratory setting to serve as replacements for damaged or diseased natural blood vessels in the human body.
These engineered blood vessels have the potential to address a variety of medical issues, including vascular diseases, vascular grafts, and bypass surgeries.
The process of creating engineered blood vessels typically involves several steps.
Cell Isolation: Cells, often smooth muscle cells and endothelial cells, are isolated from the patient’s own tissues or from donor tissues. These cells play crucial roles in the structure and function of blood vessels.
Scaffold Fabrication: A scaffold is a three-dimensional structure that provides a framework for the cells to grow and organize. Various materials can be used for scaffolds, such as biodegradable polymers or natural materials like collagen.
Cell Seeding and Culturing: The isolated cells are seeded onto the scaffold and cultured under controlled conditions to promote cell growth, proliferation, and tissue formation. This step aims to mimic the natural environment of blood vessels as closely as possible.
Maturation: As the cells grow and multiply on the scaffold, they form layers that resemble the different layers found in natural blood vessels, such as the endothelial layer and the smooth muscle layer. This maturation process enhances the mechanical strength and functional characteristics of the engineered blood vessel.
Bioreactor Stimulation: Bioreactors are specialized devices used to apply mechanical forces like pulsatile flow and pressure to the developing tissue. This helps to further enhance the tissue’s mechanical properties and physiological functionality.
Transplantation: Once the engineered blood vessel has matured and demonstrated suitable characteristics, it can be transplanted into the patient’s body to replace or repair damaged blood vessels. The advantage of using the patient’s own cells is to reduce the risk of immune rejection.
Tissue-engineered blood vessels are a promising new technology due to several reasons.
- Reduced Rejection: Using the patient’s own cells for construction reduces the risk of immune rejection, a common issue with traditional organ or tissue transplantation.
- Customization: Engineered blood vessels can be tailored to the patient’s specific needs, potentially leading to better outcomes.
- Availability: The shortage of donor blood vessels can be addressed by creating blood vessels on demand in the laboratory.
- Tissue Regeneration: These vessels can also support the regeneration of damaged tissue, promoting healing and recovery.
Despite those advantages, it is important to keep in mind that while research in this field is promising, there are still challenges to overcome, such as achieving long-term durability, preventing clotting, and ensuring proper integration with the patient’s circulatory system, all of which are in the process of research and development stage yet.
