Posts tagged tissue
Articles and news from the latest research reports.
With his knack for knowing what stem cells want, Yoshiki Sasai has grown an eye and parts of a brain in a dish.
All it took to grow a retina, it turned out, were a few tweaks, such as a reduction in the concentration of growth factors and the addition of a standard cell-culture ingredient called Matrigel. The result closely mimics eye development in the embryo. By the sixth day in culture, the brain balls start sprouting balloon-like growths of retinal cells, which then collapse in on themselves to make the double-walled optic cups. Sasai’s team snip them off — “like taking an apple from a tree”, says Sasai — transfer them to a different culture and let them be. Two weeks later, the cups have formed all six layers of the retina, an architecture that resembles the eye of an 8-day-old mouse (which, at that age, is still blind). That the cells could drive themselves through this dramatic biomechanical process without surrounding tissues to support them stunned Sasai as much as anyone else. “When I saw it, I thought, ‘Oh my god.’ Shape, topology and size are all recapitulated,” he says. Carefully explaining the pun to come, he adds: “In English, when you are surprised, you say ‘eye-popping’ — so we really thought this was eye-popping.”
(Source: nature.com)
The rat brain has served as an excellent model for elucidating the complex anatomy and physiological mechanisms of the human brain. As a result, a significant amount of information on brain diseases, such as dementia and Parkinson’s disease, has been determined from investigations using rat brains.
Protein-Based Coating Could Help Rehabilitate Long-Term Brain Function
Tuesday, July 31, 2012
TAU researchers develop bioactive coating to “camouflage” neutral electrodes
Brain-computer interfaces are at the cutting edge for treatment of neurological and psychological disorder, including Parkinson’s, epilepsy, and depression. Among the most promising advance is deep brain stimulation (DBS) — a method in which a silicon chip implanted under the skin ejects high frequency currents that are transferred to the brain through implanted electrodes that transmit and receive the signals. These technologies require a seamless interaction between the brain and the hardware.
But there’s a catch. Identified as foreign bodies by the immune system, the brain attacks the electrodes and forms a barrier to the brain tissue, making it impossible for the electrodes to communicate with brain activity. So while the initial implantation can diminish symptoms, after a few short years or even months, the efficacy of this therapy begins to wane.
Now Aryeh Taub of Tel Aviv University's School of Psychological Sciences, along with Prof. Matti Mintz, Roni Hogri and Ari Magal of TAU’s School of Psychological Sciences and Prof. Yosi Shacham-Diamand of TAU’s School of Electrical Engineering, has developed a bioactive coating which not only “camouflages” the electrodes in the brain tissue, but actively suppresses the brain’s immune response. By using a protein called an “interleukin (IL)-1 receptor antagonist” to coat the electrodes, the multi-disciplinary team of researchers has found a potential resolution to turn a method for short-term relief into a long-term solution. This development was reported in the Journal of Biomedical Materials Research.
Limiting the immune response
To overcome the creation of the barrier between the tissue and the electrode, the researchers sought to develop a method for placing the electrode in the brain tissue while hiding the electrode from the brain’s immune defenses. Previous research groups have coated the electrodes with various proteins, says Taub, but the TAU team decided to take a different approach by using a protein that is active within the brain itself, thereby suppressing the immune reaction against the electrodes.
In the brain, the IL-1 receptor antagonist is crucial for maintaining physical stability by localizing brain damage, Taub explains. For example, if a person is hit on the head, this protein works to create scarring in specific areas instead of allowing global brain scarring. In other words, it stops the immune system from overreacting. The team’s coating, the first to be developed from this particular protein, not only integrates the electrodes into the brain tissue, but allows them to contribute to normal brain functioning.
In pre-clinical studies with animal models, the researchers found that their coated electrodes perform better than both non-coated and “naïve protein”-coated electrodes that had previously been examined. Measuring the number of damaged cells at the site of implantation, researchers found no apparent difference between the site of electrode implantation and healthy brain tissue elsewhere, Taub says. In addition, evidence suggests that the coated electrodes will be able to function for long periods of time, providing a more stable and long-term treatment option.
Restoring brain function
Approximately 30,000 people worldwide are currently using deep brain stimulation (DBS) to treat neurological or psychological conditions. And DBS is only the beginning. Taub believes that, in the future, an interface with the ability to restore behavioral or motor function lost due to tissue damage is achievable — especially with the help of their new electrode coating.
"We duplicate the function of brain tissue onto a silicon chip and transfer it back to the brain," Taub says, explaining that the electrodes will pick up brain waves and transfer these directly to the chip. "The chip then does the computation that would have been done in the damaged tissue, and feeds the information back into the brain — prompting functions that would have otherwise gotten lost."
Source: Tel Aviv University
Stem cell therapy could offer new hope for defects and injuries to head, mouth
July 30, 2012
In the first human study of its kind, researchers found that using stem cells to re-grow craniofacial tissues—mainly bone—proved quicker, more effective and less invasive than traditional bone regeneration treatments.
Researchers from the University of Michigan School of Dentistry and the Michigan Center for Oral Health Research partnered with Ann Arbor-based Aastrom Biosciences Inc. in the clinical trial, which involved 24 patients who required jawbone reconstruction after tooth removal.
Patients either received experimental tissue repair cells or traditional guided bone regeneration therapy. The tissue repair cells, called ixmyelocel-T, are under development at Aastrom, which is a U-M spinout company.
"In patients with jawbone deficiencies who also have missing teeth, it is very difficult to replace the missing teeth so that they look and function naturally," said Darnell Kaigler, principal investigator and assistant professor at the U-M School of Dentistry. "This technology and approach could potentially be used to restore areas of bone loss so that missing teeth can be replaced with dental implants."
William Giannobile, director of the Michigan Center for Oral Health Research and chair of the U-M Department of Periodontics and Oral Medicine, is co-principal investigator on the project.
The treatment is best suited for large defects such as those resulting from trauma, diseases or birth defects, Kaigler said. These defects are very complex because they involve several different tissue types—bone, skin, gum tissue—and are very challenging to treat.
The main advantage to the stem cell therapy is that it uses the patient’s own cells to regenerate tissues, rather than introducing man-made, foreign materials, Kaigler said.
The results were promising. At six and 12 weeks following the experimental cell therapy treatment, patients in the study received dental implants. Patients who received tissue repair cells had greater bone density and quicker bone repair than those who received traditional guided bone regeneration therapy.
In addition, the experimental group needed less secondary bone grafting when getting their implants.
The cells used for the therapy were originally extracted from bone marrow taken from the patient’s hip. The bone marrow was processed using Aastrom’s proprietary system, which allows many different cells to grow, including stem cells. These stem cells were then placed in different areas of the mouth and jaw.
Stem cell therapies are still probably 5-10 years away from being used regularly to treat oral and facial injuries and defects, Kaigler said. The next step is to perform more clinical trials that involve larger craniofacial defects in a larger number of patients.
The study, “Stem cell therapy for craniofacial bone repair: A randomized, controlled clinical trial,” appears this month in the journal Cell Transplantation.
See the video here
Source: University of Michigan