gh CELLULAR THERAPY of ischemic stroke – outcomes of preclinical trial

Specialists of the “Trans-Technologies” Limited Liability Company and the Scientific Research Institute of Experimental Medicine (Russian Academy of Medical Sciences, St. Petersburg) are developing the methods for ischemic stroke treatment by the cellular therapy method. The researchers have observed the changes, which take place in the rats’ brain within the first six weeks of the disease, and the impact caused by mesenchymal stem cells transplantation on these processes. Experiments have proved that cellular therapy has a positive impact on the brain tissues condition after the ischemic stroke.

Cellular therapy with utilization of the mesenchymal stem cells (MSC) is one of the contemporary promising methods for ischemic stroke treatment. Specialists have grounds to hope for success. It is already known that stem cells accelerate the inflammation process course in the affected tissues, increase cell viability in the areas boundary to the injury, stimulate new blood vessel formation. Besides, MSCs (under appropriate conditions of growing) can turn into nerve cell precursors. By now, physicians have learned to educe MSCs from the marrow stroma and to grow the necessary quantity of them on the nutrient medium. This enables to graft their own cells to patients, thus avoiding immune compatibility problems. Russian physicians are now conducting preclinical trials of a new method on rats.

Ischemic stroke in the rats’ left cerebral hemisphere was achieved by pinching their middle cerebral artery. On the same day, the MSCs obtained from thigh-bones of donor rats were introduced to the experimental group animals’ caudal vein. Prior to introduction, the researchers let the cells grow on the nutrient medium, stimulated cytodifferentiation into neurons and painted them by fluorescence dyestuff. Coloration helped to observe cell transfer in the brain, which was extracted from the rats put to sleep at different stages of the experiment.

A stroke disturbs hematoencephalic barrier permeability, therefore nothing prevented stem cells from rushing to the brain immediately after injection. However, they arrived there only on the third day and settled in large quantities along external walls of inner cerebral vessels in both hemispheres but mainly – in the affected left hemisphere. (Such disposition of stem cells did not change in the course of all six weeks of observations.) It was since the third day that the researchers observed the difference in clinical course with experimental and reference rats that had not been treated by stem cells. As for the rats, which had undergone transplantation, all the processes typical of a stroke, passed by 25-30% quicker and in a more gentle form. The inflammation finished a week later with the experimental animals, and the intact nerve tissue did not become deformed. The researchers have discovered that neurons located at the border of injury, preserved normal structure with experimental rats, while all neurons perished or were damaged with the reference animals. Besides, the MSCs injection stimulated their own brain’s stem cells division.

Introduction of mesenchymal stem cells partly protects the brain from ischemic stroke consequences. But experiments carried out by the St. Petersburg researchers do not allow to expect that cellular therapy will become a panacea in this case.

***