Efectos de vecindad de la radiación ionizante y sus implicaciones en radioterapia y radioprotección
According to the classical paradigm, biological effects of ionizing radiation are attributed to DNA damage induced in each irradiated cell. Demonstration of ionizing radiation-induced bystander effects (RIBE) has generated a deep change in current understanding of radiobiology. RIBE are radiation...
Guardado en:
| Publicado en: | Revista Médica Universitaria |
|---|---|
| Autor principal: | |
| Materias: | |
| Acceso en línea: | https://bdigital.uncu.edu.ar/fichas.php?idobjeto=3402 |
| Sumario: | According to the classical paradigm, biological effects of ionizing radiation are
attributed to DNA damage induced in each irradiated cell. Demonstration of ionizing
radiation-induced bystander effects (RIBE) has generated a deep change in current
understanding of radiobiology. RIBE are radiation-induced effects produced in cells
that have not been actually irradiated. Several technical advances, particularly the use
of microbeams, allowed in vitro study of RIBE. There are two known ways by which
irradiated cells can communícate with non-irradiated cells, namely: through gap
junctions connecting the cytoplasms of adjacent cells, and through the secretion of
soluble factors to the extracellular medium. These factors include several cytokines
and reactive species of oxygen and nitrogen. In the affected cells, signalling pathways
mostly involve activation of mitogen-activated protein kinases (MAPK), NFtranscription
factor and of the enzymes cyclooxygenase 2, nitric oxide synthase 2 and
NAD(P)H oxidase. RIBE induce point mutations and epigenetic changes. Effects on
cellular signalling pathways can persist indefinitely and even be transmitted to the
progeny of affected cells. Paradoxically, under certain conditions RIBE may be
adaptive, which means that they turn affected cells more resistant to ionizing radiation.
Adaptation demands protein synthesis. It enhances DNA repair mechanisms and
resistance to oxidative stress. RIBE have also been demonstrated in vivo. Thus, they
may have important implications for radiotherapy, both to improve therapeutic efficacy
and to reduce the incidente of adverse effects. Furthermore, a better understanding of
RIBE may have an influence on international radioprotection standards.
|
|---|
