15 May 2017

Bioengineered tissue will facilitate bone marrow transplantation

Daria Zagorskaya, Vesti

Photo by Varghese lab, UC San Diego.

Our bones are not just scaffolding that supports organs and tissues in a certain position. Inside they are filled with bone marrow, which is the most important organ of the circulatory system and produces about 500 billion red and white blood cells (erythrocytes and lymphocytes) every day. It contains a large number of stem cells that are closest in structure to embryonic ones.

Severe forms of bone marrow diseases often lead to the need for its transplantation. Such patients are first exposed to radiation so that a dose of radiation destroys their own stem cells. Sometimes the treatment is accompanied by potent medications. Donor cells are populated in the vacant place. Such drastic measures are necessary in order to completely eliminate competition between the hosts and the universes and ensure the most comfortable conditions for the survival of the latter.

It is obvious that the described method of treatment is inevitably accompanied by side effects, in particular, nausea, fatigue, sometimes infertility and some others.

A promising solution to the problem was proposed by a team of bioengineers from the University of California at San Diego under the leadership of Shyni Varghese. Scientists have developed bone tissue inside which donor cells have their own space and can live and develop without being distracted by competition. The invention potentially removes the need for preliminary destruction of host cells.

A new approach described in the article by Shih et al. In vivo engineering of bone tissues with hematopoietic functions and mixed chimerism, which was published in the journal PNAS, consists in implanting bionic bone, but not inside long tubular bones, but in some other place. The implant itself is a disk of porous hydrogel, which resembles a section of the same tubular bones in structure. The outer ring of the material, like its natural counterpart – bone tissue, contains calcium phosphate.

As a result, stem cells that grow in the outer part of the implant develop into bone tissue cells, and their neighbors from the non–mineralized matrix - into hematopoietic cells.

The first tests were conducted on laboratory mice with normally functioning bone marrow and affected by radiation. The animals were implanted with implants right under the skin. After a while, they formed a structure similar to a real bone with a network of blood vessels and bone marrow, which successfully produced red blood cells. And four weeks later, both donor and their own cells were observed on the implants and in the blood of rodents. The picture was preserved after six months of the experiment.

The new method has a number of significant limitations. It is suitable only for patients whose disease does not have a malignant nature.

In a press release, Engineered Bone Marrow Could Make Transplants Safer, the authors of the study note that their results are of great importance because they demonstrate that donor cells can survive and function in the presence of their own host cells, which was previously simply impossible.

Now the main task for scientists is to obtain a sufficient number of stem cells from the bone marrow, which can be populated with implants. The researchers are confident that their invention will significantly simplify bone marrow transplantation in the future and save patients from many side effects.

Portal "Eternal youth" http://vechnayamolodost.ru  15.05.2017

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