Showing posts with label stem cells-pluripotent. Show all posts
Showing posts with label stem cells-pluripotent. Show all posts

Monday, January 30, 2012

Stem cells may shed light on hepatitis C, MIT researchers find

Stem cells may shed light on hepatitis, MIT researchers find
By Lori Valigra

Researchers at MIT and their colleagues said they have devised a way to produce liver-like cells from stem cells, a key step in studying why people respond differently to Hepatitis C.      
An infectious disease that can cause inflammation and organ failure, Hepatitis C has different effects on different people, but no one is sure why, the researchers said in a press release from MIT. Some people are very susceptible to the infection, while others are resistant.

The researchers said that by studying liver cells from different people in the lab, they may determine how genetic differences produce these varying responses. However, liver cells are hard to get and very difficult to grow in a lab dish because they tend to lose their normal structure and function when removed from the body.

The researchers, from MIT, Rockefeller University and the Medical College of Wisconsin, have come up with a way to produce liver-like cells from induced pluripotent stem cells (iPSCs), which are made from body tissues rather than embryos. Those liver-like cells can then be infected with Hepatitis C and help scientists study the varying responses to the infection.

The scientists claim this is the first time an infection has been made in cells derived from iPSCs. Their new technique is described in the Jan. 30 issue of the Proceedings of the National Academy of Sciences. The development, they said, may also eventually enable personalized medicine, in which doctors could test the effect of different drugs on tissues derived from the patient being treated and then customize therapy for that patient.

The new study is a collaboration between Sangeeta Bhatia, professor of health sciences and technology and electrical engineering and computer science at MIT; Charles Rice, professor of virology at Rockefeller; and Stephen Duncan, professor of human and molecular genetics at the Medical College of Wisconsin.

The iPSCs are derived from normal body cells, often skin cells. By turning on certain genes in those cells, the scientists can revert them to an immature state that is identical to embryonic stem cells, which can turn into any cell type. Once the cells become pluripotent, they can be directed to become liver-like cells by turning on genes that control liver development.

The researchers’ goal is to take cells from patients who have unusual reactions to hepatitis C infection, transform them into liver cells and study their genetics to see why people respond as they do. “Hepatitis C virus causes an unusually robust infection in some people, while others are very good at clearing it. It’s not yet known why those differences exist,” Bhatia said in a statement.

Monday, January 16, 2012

Behind the Headlines - Blood vessels 'grown in lab'

Behind the Headlines provides an unbiased and evidence-based analysis of health stories that make the news.

How our system works
  • Each day the NHS Choices team selects health stories that are making headlines.
  • These, along with the scientific articles behind the stories, are sent to Bazian, a leading provider of evidence-based healthcare information.
  • Bazian's clinicians and scientists analyse the research and produce impartial evidence-based assessments, which are edited and published by NHS Choices.

Blood vessels 'grown in lab' 

Monday January 16 2012

British scientists may have found a way to grow “off the shelf” veins and arteries, The Daily Telegraph today reported. The newspaper said the discovery could potentially revolutionise treatment for 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 soon.

Where did the story come from?
The study was carried out by researchers from the University of Cambridge and was 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 journal, Nature Biotechnology.

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 conclude 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, which they say is “vital for accurate assessment and therapeutic [drug] discovery”.

The researchers say that developing vascular smooth muscle cells from a patient’s own cells could also be used to construct bio-engineered blood vessels, with potential 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 functional, and could participate in blood vessel formation 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 of great use in studying a range of diseases and their potential treatments.