Microvesicles against the effects of brain irradiation
Radiation damage to the brain was cured with fragments of stem cells
Oleg Lischuk, N+1
American researchers have found that transplanting microvesicles of human stem cells into the hippocampus of rats effectively protects their brains from the effects of radiation exposure. The results of the work are published in the Proceedings of the National Academy of Sciences (Baulch et al., Cranial grafting of stem cell-derived microvesicles improves cognition and reduces neuropathology in the irradiated brain).
The effect of radiation on the brain, in particular, during radiation therapy, causes inflammation, structural changes in neurons and, as a result, impairs thinking abilities. Experiments by the staff of the University of California at Irvine have shown that implantation of human neural stem cells reduces inflammation, improves metabolism in the brain, increases neuronal plasticity and restores behavioral responses in rats exposed to ionizing radiation. However, stem cell transplantation is associated with the risk of developing tumors (teratomas) and rejection of the transplant requiring immunosuppression.
Because of this, the researchers decided to implant not whole cells, but microvesicles (ectosomes) produced by them. They are spherical fragments of cell membranes with a diameter of 100 to 1000 nanometers. Microvesicles circulating in the blood contain matrix RNA, microRNA, proteins and lipids, due to which they play an important role in intercellular communications.
Scientists exposed laboratory rats to radiation of the head at a dose of 10 Gray, after which half of them were transplanted into the brain microvesicles produced by human nerve stem cells. Animals from the control group were not exposed to radiation.
A month later, the brain functions of the animals were tested in a number of tests, such as the study of new places, new and displaced objects, as well as contextual conditioned reflex fading (checking the formation of a sense of fear). In all these tests, the results of the microvesicle recipient rats did not differ from the control group, while the irradiated animals performed significantly worse.
The immunofluorescence study showed that microvesicles were absorbed by both mature neurons and supporting astroglia cells. In addition, transplantation reduced the number of activated microglial cells (ED-1+) in the hippocampus, which indicates a decrease in inflammation of the nervous tissue. Microscopy of sections of nervous tissue impregnated with silver by Golgi-Cox showed the restoration of neurons damaged by radiation under the action of microvesicles.
Thus, ectosome transplantation of human neural stem cells proved to be an effective means of restoring the structure and functions of the brain disrupted by radiation. At the same time, the technique, unlike whole cell transplantation, does not involve the risk of developing teratomas and practically does not cause immune reactions.
Portal "Eternal youth" http://vechnayamolodost.ru
06.04.2016