Gel against limb ischemia
Researchers at the University of California at San Diego, working under the guidance of Professor Karen Christman, have proposed a promising new method for the treatment of critical limb ischemia, a condition that leads to very severe blood circulation disorders in the limbs and requires amputation of the affected areas to prevent the spread of infection and the death of healthy tissues.
Critical limb ischemia is the last stage of peripheral arterial atherosclerosis or peripheral arterial disease. This disease, affecting both women and men with the same frequency, is associated with atherosclerosis in old age, diabetes mellitus and smoking. It usually manifests itself with severe pain in the extremities. At the same time, some patients develop tissue necrosis, while others develop non–healing ulcers that become infected due to insufficient blood supply.
In many cases, traditional or endovascular surgical interventions can restore normal blood circulation in the extremities of such patients. However, in case of failure or impossibility of such interventions, amputation remains the only option for such patients.
The authors propose an alternative solution to this problem, which consists in the introduction of a gel isolated from the extracellular matrix of skeletal muscle tissue into the affected area.
Previously, they demonstrated that the introduction of a gel isolated from the cardiac muscle tissue of pigs contributes to the restoration of heart damage after myocardial infarction. To obtain a therapeutic gel, the heart muscle is cleaned of cells, leaving only the extracellular matrix acting as a microenvironment that stimulates the growth and development of new cells.
Taking this concept as a basis, the researchers created a material isolated from the skeletal muscles of pigs and designed to repair damaged muscle tissue. They injected it into the affected areas of a rat model of critical limb ischemia 7 days after the traditional surgical intervention and monitored blood flow in the limbs of animals for 35 days.
Video: fragments of skeletal muscle of pigs are mixed in detergent until the cells are completely removed, as a result of which only the fibrous extracellular matrix remains.
In the figures from top to bottom: to turn into a gel, the extracellular matrix is freeze-dried, after which it is ground into a powder, which is treated with an enzyme that provides a liquid that turns into a gel after being injected into the body.
The results showed that the introduction of the gel increased the diameter of the arterioles, which are the largest vessels of the extremities, which significantly improved blood flow. On the 35th day after the introduction of the gel, the size and structure of the muscle fibers of rats were comparable with the corresponding indicators for healthy animals.
The gel, which formed a fibrous framework after administration, also attracted muscle stem cells to the affected area. The analysis of gene expression showed that the introduction of the gel suppressed inflammatory reactions and cell death, while stimulating the mechanisms of formation of new blood vessels and muscle tissue.
At the next stages of the work, the authors plan to conduct experiments on animal models of other diseases and improve preclinical safety protocols and quality control mechanisms for industrial gel production.
Article by Jean W. Wassenaar et al. Evidence for Mechanisms Underlining the Functional Benefits of a Myocardial Matrix Hydrogel for Post-MI Treatment is published in the Journal of the American College of Cardiology: Basic to Translational Science.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of California, San Diego: New therapy could treat poor blood circulation caused by peripheral artery disease.
10.03.2016