Today, Bystander effect (radiobiology) is a highly relevant topic that has captured the attention of people of all ages and interests. With a significant impact on different aspects of daily life, Bystander effect (radiobiology) has generated debates, controversy and great interest at a global level. From its origins to its influence today, Bystander effect (radiobiology) has left an imposing mark on society, culture and history. In this article, we will explore different facets of Bystander effect (radiobiology), from its origins to its impact today, analyzing its importance and relevance in different contexts.
The radiation-induced bystander effect (bystander effect) is the phenomenon in which unirradiated cells exhibit irradiated effects as a result of signals received from nearby irradiated cells. In November 1992, Hatsumi Nagasawa and John B. Little first reported this radiobiological phenomenon.
Effect
There is evidence that targeted cytoplasmic irradiation results in mutation in the nucleus of the hit cells. Cells that are not directly hit by an alpha particle, but are in the vicinity of one that is hit, also contribute to the genotoxic response of the cell population. Similarly, when cells are irradiated, and the medium is transferred to unirradiated cells, these unirradiated cells show bystander responses when assayed for clonogenic survival and oncogenic transformation. This is also attributed to the bystander effect.
Demonstration
The demonstration of a bystander effect in 3D human tissues and, more recently, in whole organisms have clear implication of the potential relevance of the non-targeted response to human health.
Consequences
This effect may also contribute to the final biological consequences of exposure to low doses of radiation. However, there is currently insufficient evidence to suggest that the bystander effect promotes carcinogenesis in humans at low doses.
Notes
Note that the bystander effect is not the same as the abscopal effect. The abscopal effect is a phenomenon where the response to radiation is seen in an organ/site distant to the irradiated organ/area, that is, the responding cells are not juxtaposed with the irradiated cells. T-cells and dendritic cells have been implicated to be part of the mechanism.
In suicide gene therapy, the "bystander effect" is the ability of the transfected cells to transfer death signals to neighboring tumor cells.
References
^Nagasawa, H; Little, J. B. (1992). "Induction of sister chromatid exchanges by extremely low doses of alpha-particles". Cancer Research. 52 (22): 6394–6. PMID1423287.
^Prise KM, Belyakov OV, Folkard M, Michael BD (December 1998). "Studies of bystander effects in human fibroblasts using a charged particle microbeam". International Journal of Radiation Biology. 74 (6): 793–8. doi:10.1080/095530098141087. PMID9881726.