Title:Radiation-Induced Neuroinflammation and Radiation Somnolence Syndrome
Volume: 11
Issue: 7
Author(s): Paola Ballesteros-Zebadua, Anahi Chavarria, Miguel Angel Celis, Carlos Paz and Javier Franco-Perez
Affiliation:
Keywords:
Radiotherapy, neuroinflammation, radiation somnolence syndrome, sleep, cytokines, whole-brain irradiation, Cranial irradiation, malignant, benign, etiology
Abstract: Cranial irradiation remains a standard treatment for malignant and benign brain diseases. Although this
procedure helps to lengthen the life expectancy of the patient, the appearance of adverse effects related to radiationinduced
injury is inevitable. Radiation somnolence syndrome (RSS) has been described as a delayed effect observed
mainly after whole-brain radiotherapy in children. The RSS was first linked to demyelination, but more recently it has
been proposed that the inflammatory response plays a primary role in the aforementioned syndrome. To evaluate the
feasibility of this hypothesis, we explored previous work about RSS and reviewed published research that included
measurements of the inflammatory response in models of brain exposure to ionizing radiation. Pro-inflammatory
cytokines such as interleukin-1β, tumor necrosis factor-α, interleukin-6 and interleukin-18 as well as other inflammatory
markers such as cyclooxygenase-2, prostaglandin E2, glial fibrillary acid protein, intercellular adhesion molecule-1 and
nuclear factor-κB appear to be involved in the brain’s response to radiation. However, certain publications have described
the somnogenic effects of these cytokines and inflammatory markers. Although the radiation response is a complex
phenomenon that involves several molecular and cellular processes, we propose that inflammation may be closely related
to the adverse effects of brain irradiation and therefore to the etiology of RSS.
