A patch for the heart
American researchers from Brown University, together with Chinese colleagues from the universities of Suzhou and Fudan, have developed a new type of adhesive patch that can be placed directly on the heart tissue to prevent overstretching of the heart muscles, which often occurs after a myocardial infarction.
According to Professor Gao Huajian (Huajian Gao) from Brown University, one of the reasons why it is very difficult for the heart to recover after a heart attack is that it continues to pump blood. The study was based on the idea that providing damaged heart tissue with mechanical support can give it a chance to recover.
Earlier studies have shown that mechanical "patches" can be effective in this situation, but none of the researchers have found out what optimal mechanical properties such a patch should have. Therefore, the thickness and density of potential patches have so far varied widely.
Hearts with a patch optimized by computer simulation (second column on the left) underwent less remodeling (shape change) than hearts without a patch (leftmost column) and hearts with patches having suboptimal properties (right columns).
According to the authors, too hard or weakly elastic material can restrict the movement of the heart so that it will not be able to increase to the desired volume. At the same time, too soft material will not provide sufficient support. To develop the principles of determining the "correctness" of the material, the authors created a computer model of a contracting heart that reproduces the mechanical dynamics of both the heart itself and the patch attached to its outer surface. In addition, the model consisted of two parts, one of which reproduced the normal function of the heart – expansion and contraction. A patch simulation was applied to it and observed how it affects the functions of the heart. The second part was a model of heart remodeling after myocardial infarction. It allowed the researchers to determine exactly what kind of mechanical support the heart needs to prevent this process.
Based on the data obtained using the model, the authors developed a hydrogel material based on food starch. The key property of the resulting hydrogel is viscoelasticity. This means that it simultaneously has the properties of a liquid and a solid material, that is, up to a certain level of load, it retains a certain level of "liquid", after which it is compacted. This makes the material ideal both for adapting to the movements of the heart and for providing sufficient support.
In addition, the material is very cheap (according to the researchers, the bookmark costs less than a penny) and easy to manufacture, and experiments have shown that it has no toxicity. And the results of studies on rats confirmed its effectiveness in reducing the severity of post-infarction injuries.
The authors explain that the patch provided the heart tissue with almost optimal mechanical support after massive cardiomyocyte death. This was manifested by better preservation of cardiac output, which reduced the load on the preserved cardiomyocytes and effectively prevented remodeling of the left ventricle, which usually occurs after a myocardial infarction, stretching of the heart muscle, which can significantly worsen the function of the main pumping department of the heart.
The analysis of biochemical markers also showed that the use of the bookmark reduced cell death, as well as suppressed the formation of scar tissue and oxidative stress in the area of damage.
In addition, the researchers demonstrated that the results provided by the patch optimized with the help of computer simulation are superior to the results of using earlier patches, the mechanical properties of which were selected at random.
The authors note that further testing of the approach is necessary, but the initial results give great hopes that sooner or later the new technology will pass the stage of clinical research and take its place in medical practice.
Article by Xiao Lin et al. A viscoelastic adhesive epicardial patch for treating myocardial infarction is published in the journal Nature Biomedical Engineering.
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru according to Brown University: Heart patch could limit muscle damage in heart attack aftermath.