Blood vessels 'grown in lab'
British scientists may have found a way to grow “off the shelf” veins and arteries, The Daily Telegraph has reported.
The newspaper said the discovery could potentially revolutionise treatment for a range of conditions.
In the study behind the story, researchers looked at “pluripotent” stem cells, which are early biological cells that can change into other cell types and renew themselves to produce more stem cells. The researchers then developed methods for turning the stem cells into various types of vascular smooth muscle cells, which form the walls of blood vessels. They did this by first turning them into different “intermediary” cell types. The vascular smooth muscle cells produced were in working order and could help to form blood vessels when injected into mice.
These findings mean that the researchers can now create models of different blood vessels. These models could be used to test new drugs and to investigate why some cell types/blood vessel types are more susceptible to disease than others. In future, it may also be possible to grow the right type of blood vessel cells from a patient’s own cells for use in surgery.
This is an exciting advance, with many potential uses for the findings. However, growing “off the shelf” veins and arteries will require much more research, so these are unlikely to be available for the public soon.
Where did the story come from?
The study was carried out by researchers from the University of Cambridge and funded by the Wellcome Trust and the Cambridge National Institute for Health Research Comprehensive Biomedical Research Centre. The study was published in the peer-reviewed Nature Biotechnology journal.
The research was covered by The Daily Telegraph and the Daily Mail. Although the coverage was mainly accurate, there was a lot of emphasis on how the findings could be used, with no mention that these would require much more research and testing before they can be applied.
What kind of research was this?
It’s well known that a range of different vascular smooth muscle cell types are found in the walls of different blood vessels in the body. The walls of different vessels are made up from different cell types, which in turn have been formed from different “precursor cells” during their development. Scientists have speculated that the different origins of vascular smooth muscle cells might be why certain blood vessels are more susceptible to disease.
This study aimed to develop methods for deriving different vascular smooth muscle cells from human “pluripotent” stem cells, which have the potential to mature into a range of different cells types. The researchers did this with a view to investigating how susceptible to disease different blood vessels are, and so that cells for particular blood vessels could be grown in the laboratory, which could have therapeutic applications.
To carry out this research, the researchers performed a laboratory-based study, which was the only feasible way to develop these methods.
What did the research involve?
The researchers developed different processes to cause human pluripotent stem cells to develop into different intermediary stages and then into vascular smooth muscle cells. This was achieved by exposing the cells to different amounts of certain chemicals, such as inflammatory mediators and growth factors known to regulate cell division.
The researchers checked that the developed vascular smooth muscle cells functioned normally by seeing if they responded correctly to specific signals and if they formed blood vessels when injected into mice.
The researchers then investigated whether the cells they developed in the laboratory were similar to cells in the body.
What were the basic results?
The researchers were able to develop methods for generating vascular smooth muscle cells through three different intermediary stages. The blood vessel cells produced were in working order and could help to form blood vessels when injected into mice. They also responded to different chemicals differently, depending on how they were generated, and their responses were consistent with those of natural vascular smooth muscle cells in the body.
How did the researchers interpret the results?
The researchers concluded that the ability to produce large amounts of vascular smooth muscle cell subtypes from human pluripotent stem cells could have “far-reaching applications”. The ability to derive different types of vascular smooth muscle cells could allow the modelling of diseases in the lab: “vital for accurate assessment and therapeutic [drug] discovery”.
The researchers also concluded that developing vascular smooth muscle cells from a patient’s own cells could also be used to construct bio-engineered blood vessels, with applications including heart and artery bypasses or grafts at the site of haemodialysis.
In this study, researchers developed methods for generating vascular smooth muscle cells, which form the walls of blood vessels, from pluripotent stem cells via three different intermediate stages. The cells they produced were in functional, working order and could help to form blood vessels when injected into mice.
It’s already well known that the body uses different types of vascular smooth muscle cell to make up the walls of different blood vessels, and that these cells are themselves formed from different precursor cells during development. This latest advance in knowledge will allow different blood vessels to be modelled for research purposes, particularly to see why some of them are more susceptible to disease than others and to test new drugs.
In future, it may also be possible to grow the right type of vascular smooth muscle cell from a patient’s own cells for use in surgery. However, these applications will require much more research, and are unlikely to be available soon due to the lengthy testing required to establish their safety and reliability.
In short, although much news coverage has focused on being able to replace patients’ blood vessels with those grown in a lab, the principal application for this technology is furthering our ability to research blood vessels and related diseases. While this may not seem as exciting as directly treating patients, the research will still be very useful in studying a range of diseases and their potential treatments.
- Cheung C, Bernardo AS, Trotter MWB et al. Generation of human vascular smooth muscle subtypes provides insight into embryological origin–dependent disease susceptibility. Nature Biothechnology, published online January 15 2012