Prenatal x-ray exposure may increase risk of schizophrenia: Results from the Jerusalem perinatal cohort schizophrenia study

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT: PART II - RADIATION CEREBRO/OPHTALMIC EFFECTS IN CHILDREN, PERSONS EXPOSED IN UTERO, ASTRONAUTS AND INTERVENTIONAL RADIOLOGISTS

BACKGROUND

Ionizing radiation (IR) can affect the brain and the visual organ even at low doses, while provoking cognitive, emotional, behavioral, and visual disorders. We proposed to consider the brain and the visual organ as potential targets for the influence of IR with the definition of cerebro-ophthalmic relationships as the «eye-brain axis».

OBJECTIVE

The present work is a narrative review of current experimental, epidemiological and clinical data on radiation cerebro-ophthalmic effects in children, individuals exposed in utero, astronauts and interventional radiologists.

MATERIALS AND METHODS

The review was performed according to PRISMA guidelines by searching the abstract and scientometric databases PubMed/MEDLINE, Scopus, Web of Science, Embase, PsycINFO, Google Scholar, published from 1998 to 2021, as well as the results of manual search of peer-reviewed publications.

RESULTS

Epidemiological data on the effects of low doses of IR on neurodevelopment are quite contradictory, while data on clinical, neuropsychological and neurophysiological on cognitive and cerebral disorders, especially in the left, dominant hemisphere of the brain, are nore consistent. Cataracts (congenital - after in utero irradiation) and retinal angiopathy are more common in prenatally-exposed people and children. Astronauts, who carry out longterm space missions outside the protection of the Earth's magnetosphere, will be exposed to galactic cosmic radiation (heavy ions, protons), which leads to cerebro-ophthalmic disorders, primarily cognitive and behavioral disorders and cataracts. Interventional radiologists are a special risk group for cerebro-ophthalmic pathology - cognitivedeficits, mainly due to dysfunction of the dominant and more radiosensitive left hemisphere of the brain, andcataracts, as well as early atherosclerosis and accelerated aging.

CONCLUSIONS

Results of current studies indicate the high radiosensitivity of the brain and eye in different contingents of irradiated persons. Further research is needed to clarify the nature of cerebro-ophthalmic disorders in different exposure scenarios, to determine the molecular biological mechanisms of these disorders, reliable dosimetric support and taking into account the influence of non-radiation risk factors.

NEUROENDOCRINE EFFECTS OF PRENATAL IRRADIATION FROM RADIOACTIVE IODINE (review)

BACKGROUND

Neuroendocrine effects of the prenatal radiation exposure from radioactive iodine in an event of nuclear power reactor accidents are a key issue in the field of radiation medicine and radiation safety because of a dramatic radiosensitivity of the developing organism.

OBJECTIVE

Review of contemporary epidemiological, clinical and experimental data on neuroendocrine effects of prenatal exposure to 131I.

OBJECT AND METHODS

Search in the PubMed/MEDLINE and Google Scholar abstract databases, along with a manual search for the relevant data sources.

RESULTS

Estimated absorbed doses of intrauterine thyroid irradiation from radioactive iodine were obtained based on ICRP Publication 88, both with estimates of effective radiation doses on embryo and fetus, and estimates of the brain equivalent doses upon exposure in utero. The latter ones are subject to updating. The evidence-based data has been presented regarding a radiation-associated reduction of head and chest circumference at birth, as well as a radiation-associated excess of goiter with large thyroid nodules, and possibly of thyroid cancer after a prenatal exposure to 131I radionuclides. Data on intrauterine brain damage are controversial, but most researchers share the view that there are cognitive and emotional-behavioral disorders due to prenatal and postnatal irradiation and psy- chosocial impacts. Incidence increase of non-cancerous endocrine disorders and degenerative vascular disease of retina was noted. An experimental model of intrauterine irradiation from 131I on Wistar rats was for the first time ever created, extrapolating the radioneuroembryological effects in rats to individuals prenatally exposed after the Chornobyl disaster. Late neuropsychiatric and endocrine effects may be resulted from the relatively short-term impact of ionizing radiation at a level previously been considered safe. The necessity of neuropsychiatric and endocrinological monitoring of individuals exposed prenatally to ionizing radiation after the Chornobyl catastrophe throughout their life is substantiated. Experimental animal studies are a key direction in the further research of radiation effects, especially associated with low radiation doses. Further experimental and clinical neuroradiobio- logical studies aimed at exploration of the effect of ionizing radiation on hippocampal neurogenesis are most rele- vant nowadays.