New Discovery to Repair Scar Tissue
Meghan Hegarty (12:00 Micro) found an article in Science Daily, which describes research examining how differentiated cells might be reprogrammed to better help with the healing process. For the curious among us, the compounds described by Meghan down below which promote this reprogramming are molecules that mimic viral RNA genomes, and as a result can stimulate certain host cell signalling pathways that we will learn about in the next chapter in Bauman. Here is Meghan’s summary:
Recent discoveries have shown that by transforming human scar cells into blood vessel cells, the repair of damaged tissue can be completed. Cardiovascular scientists of Houston Methodist and several others from Stanford University and Cincinnati Children’s Hospital learned new information that can remove scars. By coaxing fibroblasts into becoming endothelium, a different type of adult cell forms, creating the lining for blood vessels.
According to John Cooke of the Houston Methodist Research Institute Department of Cardiovascular Sciences, this is the first time a transformation of cell type has been completed along with the use of molecules and proteins. By turning fibroblasts into new cells, the possibility of molecule therapy to improve the healing process of cardiovascular damage or other scars may now be an option. Another way to generate endothelial cells is to use infectious virus particles to manipulate genes in DNA. To do this, DNA must encode proteins to alter gene patterns in a way that behave like endothelial cells. However, John Cooke states the using viruses to transfer genes into cells can cause multiple problems. This approach is more complicated and the possibility of damage to the patient’s chromosomes is higher. Manipulating fibroblasts is easier to complete and overall safer for clinical therapies.
To complete the method that Cooke suggests, fibroblasts have to be exposed to polyinosinic: polycytidylic acid that binds to toll-like receptor 3 which tricks the cells into reacting, like they are being attacked by a virus. This can be described as fibroblasts responding to a fake viral attack, which is an important step in the transformation of fibroblasts to new cells. After treating fibroblasts with polyinosinic: polycytidylic acid, other factors come in to play to compel less differentiated cells into becoming endothelial cells.
Rates of fibroblast transformation are somewhat low now, at only two percent of the fibroblasts transforming into endothelial cells, but the transformation rates are expected to get as high as fifteen percent. Cooke explains that this rate will provide the perfect amount of transformed cells, as not all fibroblasts need to be transformed. Fibroblasts perform important functions such as making proteins that hold tissue together. The approach to transforming fibroblasts will transform some of the scar cells into blood vessel cells that will allow blood flow to heal an injury.
In another part of the study completed, scientists introduced transformed human cells into immune-deficient mice that had a poor blood flow to their back legs. By incorporating human blood vessel cells into the mice, there was an increase in the number of vessels in the mouse limb which overall improved their circulation. The cells self assemble to form new blood vessels by joining with existing vessels in the mice. By figuring out how to manipulate adult cells of one type into a different type of cell, further development of regenerative medicine can be completed. Considering humans are usually unable to regenerate heavily damaged tissue, this process can become very important.
If the scientists can understand the underlying pathways and how to manipulate them to benefit people, new information to reawaken important mechanisms for regeneration can be discovered. More animal studies are needed before the scientists can begin clinical trials, such as seeing if they can heal an animal from an injury by this new method. Before testing this on humans, the scientists want to know if the therapy enhances the healing process by increasing blood flow to tissues that may have been damaged by a loss of blood.