The system developed in Prof. Levenberg's laboratory stretches the tissue and relaxes it alternately, thereby effectively imitating the cycle of muscle contraction in the body. In the series of experiments conducted in the laboratory, it became clear that the tensile forces applied to the tissue do affect the direction of the blood vessels
A method developed at the Technion significantly improves the quality of artificial tissues intended for transplantation. The improved tissues are absorbed by the body faster and their blood vessels coordinate optimally with those of the host tissue. The study, which provides preclinical evidence for the method's effectiveness in transplanting tissue in the abdominal area, was recently published in the journal PNAS.
The said research is led by Prof. Shulamit Levenberg, head of the laboratory for tissue and stem cell engineering in the Faculty of Biomedical Engineering at the Technion. In the last decade, since her post-doctorate at MIT, Prof. Levenberg has been developing XNUMXD biodegradable polymer scaffolds on which she grows biological tissues intended for transplantation in the laboratory. These scaffolds, on which biological cells (fibroblasts and endothelial cells) essential for the development of blood vessels are seeded, lead to the formation of tissues that are efficiently absorbed by the body.
In order for a transplanted tissue to be well absorbed in the body, it is important that the blood vessels in it match the direction of the blood vessels in the host tissue. This is because the fusion between the blood vessels of the two tissues is critical to the success of the transplant. Methods for creating tissues that include blood vessels are an essential component of regenerative medicine, as they ensure a regular supply of oxygen and nutrients in the tissue that hosts essential resources for the absorption and survival of the graft. The aforementioned adjustment improves the absorption of the implant and the mechanical properties of the implantation site, an important component in the reconstruction of defects in the abdominal area, which was tested in the present study.
Various studies have tried to improve the properties of the blood network in the tissue intended for transplantation by means of a substrate that includes biological factors, biomaterials and geometrical constraints. It is now known that external mechanical forces such as pressing, stretching and compression affect the biological processes in the cell and even its differentiation, shape, migration and organization as well as the geometry of the tissue, its maturity and stability. However, so far the effect of these forces on blood vessel formation at the whole tissue level has not been tested.
In the current study, Prof. Levenberg examined the effect of tensile forces on the network of blood vessels formed in the tissue intended for transplantation. Static stretching, the study reveals, leads to the growth of blood vessels parallel to the direction of the stretch, while cyclic stretching leads to the growth of blood vessels in a diagonal dimension. In addition, the study examined the biological conditions necessary for the creation of improved tissues, which will be quickly and efficiently absorbed into the target tissue.
According to Prof. Levenberg, "The morphology of the vascular network varies from tissue to tissue. For example, the blood vessels in muscle tissue are arranged parallel to the muscle fibers, while in retinal tissue they are arranged in a circular fashion. Our hypothesis was that the tensile forces exerted on the tissue play a central role in determining the characteristics of the vascular network formed in it. Furthermore, we hypothesized that the transplantation of a vascular network created according to the properties of the host tissue would improve the fusion of the transplanted tissue and its function in the body over time. Here, for the first time, we tested blood vessel networks in tissue that were organized under cyclic and static tensile forces."
The system developed in Prof. Levenberg's laboratory stretches the tissue and relaxes it alternately, thereby effectively imitating the cycle of muscle contraction in the body. In the series of experiments conducted in the laboratory, it became clear that the stretching forces applied to the tissue do affect the direction of the blood vessels, and that the best result was achieved with cyclic stretching. "The cyclical stretching led to the fact that the blood vessels develop in the tissue in a good way and are organized in a defined manner according to the forces exerted on them."
Now, in order to test the suitability of the targeted engineered tissue, the researchers implanted it in the stomach of a mouse and discovered that implants created by the process of stretching do integrate quickly with the host tissue. These grafts are absorbed faster than grafts grown without stretching or grafts grown with stretching and transplanted in an orientation that does not correspond to the blood vessels in the mouse at the transplant site. "Actually, we are talking about a very short period of time - about a week of creating the tissue in the laboratory and another two weeks in the animal. At the end of this period of about three weeks, we see excellent absorption of the tissue in the body and a return of the absorbing tissue to full activity."
Prof. Levenberg, a world-renowned expert in the fields of stem cells and tissue engineering, joined the Faculty of Biomedicine at the Technion after a post-doctorate with Prof. Robert Langer at MIT. One of her most important developments is a technology for creating biodegradable polymer scaffolds, on which she grows complex biological tissues in the laboratory for transplantation. These engineered tissues lead to optimal absorption of implants and consumables in the body. Prof. Levenberg won the Krill Award from the Wolf Foundation for excellence in scientific research. Scientific American magazine included her in the list of the fifty most influential people in the world as a scientific leader in the field of tissue engineering. The main part of the research in the laboratory was done by Dr. Dekel Dado-Rosenfeld as part of her doctoral thesis under the guidance of Prof. Levenberg (Dekel is currently in a postdoctoral position at MIT, with the assistance of a joint merit scholarship for the Technion and MIT) The work was done in collaboration with Prof. Dave Mooney from Harvard with whom she was hosted Prof. Levenberg on sabbatical.
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Regarding the tissues growing on stilts, I understood that there was a breakthrough in the world and they managed to industrially develop organ growth on a XNUMXD printed polymeric organ with a hole that is eaten inside the body, so that the body will not reject the transplant because it is composed of the donor's cells (stem cells?). A good question is whether Israel can trade such knowledge, because elsewhere it has already been traded. Here we hear that the organ will also experience muscle movements - in short, if I understand, the world is going to create organs for transplantation in the laboratory. Very nice.
She is a religious professor and there are others like her, for example Professor Yunina Alder and many more. She is also in microbiology. That one of them would have the courage to say out loud that the theory of evolution is true, that the big bang seems true, and that gays have a right to exist just like normal.