One of the basic processes happening during tissue regeneration is transformation of epithelial cells into mesenchymal and the other way around, mesenchymal cells into epithelial. The term is epithelial-mesenchymal transition. The picture above shows the difference between these two basic cell phenotypes. Note, that there are no other ones in multicellular tissues. Epithelial cells are bound tightly to each other and to extracellular matrix. The extracellular matrix is the basal lamina, which serves as a sort of bed for epithelial cells, which form a “topping”. Mesenchymal cells are located within a 3D extracelllular matrix. They are bipolar, which means they have different cytoskeleton arrangement and distinct organelle distribution inside them. For example, mesenchymal cells have lamellipodia at their leading edge. These structures help them migrate inside the tissue.
Tag Archives: regenerative medicine
Surgeon Anthony Atala of Wake Forest University Baptist Medical Center used lab-grown urethras to treat patients with damaged urinary tracts.
Five boys aged 10 to 14 were involved in the study and it took place at the Federico Gomez Children’s Hospital in Mexico City. Basically, Atala took each patient’s bladder cells and grew the cells on a scaffold. After about four to seven weeks, the cells grew into an ideal structure on the mesh-like tube and soon enough, the cells were ready for implantation.
At that point, the damaged tissue was removed and surgically replaced with the regenerative tissue custom-made for each patient. The urethra function in the male patients returned to normal and it only took three months. Even six years in, the tissue appeared to be working normally. Currently, treatment for damaged urethras involves skin grafts – but the failure rate of skin grafts is about 50 percent.
Researchers at the Cincinnati Children’s Hospital Medical Center have recently made functional human intestinal tissue from pluripotent stem cells. The researchers project that this will push the boundaries of research into how the intestines develop and work. It will also help with understanding the diseases that affect this organ and aid in producing intestinal tissues for transplant.
The study’s senior investigator, James Wells, Ph.D, stated that this was the first time cells in a petri dish were programmed to efficiently mimic the cell structures of human intestinal tissue. Regarding the future applications of this find, he said, “The hope is that our ability to turn stem cells into intestinal tissue will eventually be therapeutically beneficial for people with diseases such as necrotizing enterocolitis, inflammatory bowel disease and short bowel syndrome.”
Researchers at Cambridge and Edinburgh have discovered a way for stem cells in the brain to regenerate myelin, which is needed to protect nerve fibers. The studies, performed on rats, are exciting because they offer new hope that in the future, the damage done by multiple sclerosis could be repaired and physical function lost by patients could be restored.
The studies indicated that the patient’s own brain could be stimulated to regenerate myelin. Professor Charles ffrench-Constant, one of the lead researchers, was hopeful that the discoveries made could lead to the development of new drugs. “The discovery is very exciting as it could potentially pave the way to find drugs that could help repair damage caused to the important layers that protect nerve cells in the brain.”
Researchers at the State University of Buffalo, New York have come up with a way to grow adult stem cells continuously, offering a way to speed development of regenerative therapies. The research team, led by prof. Techung Lee, have engineered adult stem cells that scientists can grow continuously in culture.
One of the obstacles in studying adult stem cells has always been that they tend to die after only a few weeks. Techung Lee, said he and his students were growing frustrated by that, so he decided it was time to solve that problem once and for all. “We were annoyed by the inconvenience of harvesting bone marrow,” he said.
Considering the success of the moon race, why isn’t there a comparable race against aging and its terrible diseases? Why is there so much opposition to promising developments such as therapeutic cloning or stem cell research? Why is modern medicine, and society at large, investing so much in trying to extend the last years of life (often spent in a nursing home) instead of trying to extend the period of youthful vigor?
Mainstream medicine, called “Mortalist Medicine,” operates from the mortalist paradigm: it assumes that aging is “normal” and nothing can be done about it. Weight gain, hearing and vision loss, a rise in blood pressure, a decline in muscle mass—all these are regarded as normal manifestations of aging. Since aging is not regarded as a disease, much less the most important disease, it is acceptable to treat only the symptoms of this universal, underlying degenerative syndrome. It is OK to treat heart disease or Alzheimer’s, but not OK to try to slow the aging process itself, much less aim at physiological rejuvenation—even though this would be the most cost-effective solution to the catastrophic rise in medical costs as the population ages.
We think medicine badly needs a paradigm shift. Aging itself must be classified as a disease—“the master disease, the one disease that will sooner or later kill every one of us on this planet, unless we decrypt its legal code. This view of aging is already accepted by regenerative medicine, which tries to regenerate and rejuvenate the body. Physicians practicing regenerative medicine understand that the most cost-effective approach to combating various “diseases of aging” is to keep the patient physiologically young.
The time has come for man to get over his cosmic inferiority complex. To rise above his condition – and to use technology to extend himself beyond his biological limitations.
Yesterday, the New American Foundation and Arizona State University with help from the IEET’s Sean Hays and with Aubrey de Grey as a main speaker, sponsored a conference on the future of life extension and its global ramifications: economic, social, and political.
Will 250 be the new 100 in the foreseeable future? As we discuss on my blog, human life expectancy has made steady gains over the last two centuries, and anti-aging scientists are eager to trigger a radical extension in our life spans. How likely is such a spike? And how desirable is it to live to be a quarter of a millennium? These were the core questions that were addressed at the conference.
At the conference, Aubrey de Grey (IEET Fellow and Chief Scientist, SENS Foundation) said that “radical life extension is a turn-off to a lot of people, especially people on Capitol Hill, because they imagine it as people getting old and extending the frail and infirmed portion of their lives indefinitely. This is a pretty old understanding of radical life extension.” Aubrey de Grey argued that instead of maximizing the existing life expectancy with drugs and diet, using “regenerative medicine,” periodic repair of the mechanism, is the avenue to achieve real gains in life expectancy. He spoke against attitudes on the demographic consequences of life expectancy since the effects will only accumulate over the next century. According to de Grey, the policy we need to care about is making the case for more research monies for the biology and therapy of aging today, not dealing with consequences of having a society full of centenarians.
Scientists at McMaster University have discovered how to transform human skin into blood. The researchers had previously used chemicals to transform mouse skin cells into neurons, but this is the first time human cells have been altered in this manner.
The team created blood progenitor cells, the mother cells that multiply to produce other blood cells as well as mature blood cells. Both types of cells are useful in medical treatments, said study leader Mick Bhatia, a stem cell scientist at McMaster University in Hamilton, Ontario.
Bhatia’s team had been focused on generating blood cells for more than 10 years. Stem cells weren’t efficient at generating blood cells that were suitable for clinical use so for the past two years, the team has been converting skin cells directly into blood cells.