Nanomagnets against infarction
Is it possible to replace the myocytes that died as a result of myocardial infarction with healthy cells? A group of researchers from the University of Bonn (Germany) tested an innovative method on mouse models: embryonic cardiomyocytes, which should restore the function of the damaged heart muscle, were loaded with magnetized nanoparticles before transplantation. The models created in this way showed a significant improvement in heart function.
In myocardial infarction, there is a violation of the nutrition of the heart muscle, which leads to the death of muscle cells and a decrease in the contractility of the heart. Work on restoring heart function by transplanting muscle cells has been going on for a long time. The problem was to detain them in the heart tissue – the pressure created by the contraction of the heart pushed them through the injection channel immediately after administration, so the reparative effect was limited.
Mice that had suffered a myocardial infarction were injected into the damaged areas of the heart with embryonic cardiomyocytes, both already differentiated and obtained in the laboratory from the ESC culture, having previously placed magnetized nanoparticles on them. To track the location of the transplanted cells, the researchers tagged them with a green fluorescent protein.
Immediately after cell management, a magnet was placed 5 millimeters from the heart, and then the degree of cell engraftment was assessed 2 and 8 weeks after treatment. A magnet located near the injection site held about 60% of the stem cells in place. For comparison, the average number of cells remaining at the injection site without a magnetic field was 25%.
In the mouse heart, muscle stem cells with magnetized nanoparticles are injected into the infarction zone through a cannula. Source: Annika Ottersbach/Uni Bonn.
10 minutes of exposure to the magnet was enough to hold the transplanted cells, and they remained in place even a few weeks after administration, gradually penetrating into the surrounding tissue.
Surprisingly, after a myocardial infarction, when cells experience oxygen starvation, stem cells with magnetized nanoparticles survived and began to divide more intensively than transplanted cells without nanoparticles. As the authors suggest, under the influence of a magnetic field, the cells were located denser, which ensured more active growth than when transplanting stem cells without nanoparticles. Moreover, the activity of genes responsible for cell survival, for example, cellular respiration, was higher than in cells without nanoparticles.
In comparison with the group of mice that received stem cells without exposure to a magnet, the number of engrafted cells transplanted with nanoparticles exceeded seven times in two weeks, and four times in two months. Given the short lifespan of mice, such results are really impressive.
The functions of the cardiac muscle of mice after transplantation of cells with magnetic nanoparticles improved significantly.
Scientists have no doubt that this method can be used to treat people in the future, although they recognize that there is still a very long way to go before it is introduced into clinical practice and more than one study needs to be conducted.
Article by Annika Ottersbach et al. Improved heart repair upon myocardial infarction: Combination of magnetic nanoparticles and tailored magnets strongly increases the engraftment of myocytes is published in the journal Biomaterials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Bonn: Fighting myocardial infarction with nanoparticle tandems.