Cognitive, psychological and psychiatric effects of ionizing radiation exposure

Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, University of Pisa, Via Roma, 67, I- 56100 Pisa, Italy.
Current Medicinal Chemistry (Impact Factor: 3.85). 02/2012; 19(12):1864-9. DOI: 10.2174/092986712800099776
Source: PubMed

ABSTRACT Radiation exposure leads to an increased risk for cancer and, possibly, additional ill-defined non-cancer risk, including atherosclerotic, cardiovascular, cerebro-vascular and neurodegenerative effects. Studies of brain irradiation in animals and humans provide evidence of apoptosis, neuro-inflammation, loss of oligo-dendrocytes precursors and myelin sheaths, and irreversible damage to the neural stem compartment with long-term impairment of adult neurogenesis. With the present paper we aim to present a comprehensive review on brain effects of radiation exposure, with a special focus on its impact on cognitive processes and psychological functions, as well as on their possible role in the pathophysiology of different psychiatric disorders.

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    • "The interpretation of these findings remains difficult due to confounding factors such as environmental mental stress, other possible chemical or physical contaminants in work habitat, night shift, and socio-economic confounders. Radiation is only a potential - but unproven - source of bioeffects, but certainly more data are warranted [92]. "
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    ABSTRACT: Background According to a fundamental law of radiobiology (“Law of Bergonié and Tribondeau”, 1906), the brain is a paradigm of a highly differentiated organ with low mitotic activity, and is thus radio-resistant. This assumption has been challenged by recent evidence discussed in the present review. Results Ionizing radiation is an established environmental cause of brain cancer. Although direct evidence is lacking in contemporary fluoroscopy due to obvious sample size limitation, limited follow-up time and lack of focused research, anecdotal reports of clusters have appeared in the literature, raising the suspicion that brain cancer may be a professional disease of interventional cardiologists. In addition, although terminally differentiated neurons have reduced or mild proliferative capacity, and are therefore not regarded as critical radiation targets, adult neurogenesis occurs in the dentate gyrus of the hippocampus and the olfactory bulb, and is important for mood, learning/memory and normal olfactory function, whose impairment is a recognized early biomarker of neurodegenerative diseases. The head doses involved in radiotherapy are high, usually above 2 Sv, whereas the low-dose range of professional exposure typically involves lifetime cumulative whole-body exposure in the low-dose range of < 200 mSv, but with head exposure which may (in absence of protection) arrive at a head equivalent dose of 1 to 3 Sv after a professional lifetime (corresponding to a brain equivalent dose around 500 mSv). Conclusions At this point, a systematic assessment of brain (cancer and non-cancer) effects of chronic low-dose radiation exposure in interventional cardiologists and staff is needed.
    BMC Cancer 04/2012; 12(1):157. DOI:10.1186/1471-2407-12-157 · 3.32 Impact Factor
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    • "Thus, exposure to radiation has multiple effects on the brain, behavior and cognitive functions. These changes depend largely on the radiation dose (Wong and Van der Kogel 2004, Gourmelon et al. 2005, Loganovsky 2009, Marazziti et al. 2012, Picano et al. 2012). "
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    ABSTRACT: Objective: Cognitive impairment in the remote period of Acute Radiation Sickness (ARS) is an expected outcome. This study was performed to examine the contribution of irradiation on intelligence deterioration. Method: 14–15 years after the Chernobyl accident, a cross-sectional IQ-study on ARS-patients (n=29) and normal controls (n=24) was done. Verbal (VIQ), Performance (PIQ) and Full (FIQ) IQs were assessed by the adapted version of the Wechsler Adult Intelligence Scale (WAIS). Pre-exposure IQ was estimated by the regression equation developed by Dr. Beilin Gao (China). Results: VIQ and FIQ scores were lower in ARS-patients than in controls (M±SD: 103.2±13.5 vs 113.8±9.4, and 102.2±11.4 vs 110.2±8.6, correspondingly). Radiation dose of 1 Gy decreases FIQ of 4.1–6 scores at a dose range of 1–3.8 Gy. A reduction of 1 point of FIQ could be a result of exposure to 0.17–0.24 Gy. Discrepancy between pre-exposure and actual IQ (M±SD) in ARS-patients is dramatically severe as compared to controls: VIQ -15.8±14.4 vs 2.3±4.5, PIQ -14.2±10.8 vs 8.7±3.5, and 16.8±12.7 vs 5.9±2.6, correspondingly. Conclusions: According to pre-exposure IQ estimations, IQ deterioration in ARS-patients, especially, in verbal and full intelligence, was observed. Such cognitive impairment could be evidence of a brain organic syndrome with an important involvement of the left dominant hemisphere, in the remote period of ARS.
    Clinical Neuropsychiatry 01/2012; 9(5):187-194.
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    ABSTRACT: Radiation therapy is a part of the standard treatment for brain tumor patients, often resulting in irreversible neuropsychological deficits. These deficits may be due to permanent damage to the neural stem cell (NSC) niche, damage to local neural progenitors, or neurotoxicity. Using a computed tomography-guided localized radiation technique, we studied the effects of radiation on NSC proliferation and neuroblast migration in the mouse brain. Localized irradiation of the subventricular zone (SVZ) eliminated the proliferating neural precursor cells and migrating neuroblasts. After irradiation, type B cells in the SVZ lacked the ability to generate migrating neuroblasts. Neuroblasts from the unirradiated posterior SVZ did not follow their normal migratory path through the irradiated anterior SVZ. Our results indicate that the migrating neuroblasts were not replenished, despite the presence of type B cells in the SVZ post-irradiation. This study provides novel insights into the effects of localized SVZ radiation on neurogenesis and cell migration that may potentially lead to the development of new radiotherapy strategies to minimize damage to NSCs and neuroblast migration. STEM CELLS2012;30:2548-2560.
    Stem Cells 11/2012; 30(11):2548-60. DOI:10.1002/stem.1214 · 7.70 Impact Factor
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