Intermediate risk factors in ionising radiation cataractogenesis

Area of Science:

• Ophthalmology
• Radiation Biology
• Biochemistry

Background:

• Recent reports propose a two-stage etiology (initiation and maturation) for radiation-induced cataracts, specifically posterior subcapsular cataract (PSC) and cortical cataracts.
• Mechanisms involve oxidative stress, ocular ion imbalance, inflammation, and altered oxygen levels, relevant to atomic bomb survivors.
• Calcium metabolism dysregulation, including overload, is implicated as a cataractogenic factor.

Purpose of the Study:

• To explore the link between low-dose ionizing radiation and cataractogenesis, considering recent etiological concepts.
• To evaluate preliminary findings in atomic bomb survivors regarding inflammation and calcium levels in relation to cataract development.
• To investigate the relevance of these findings to cataracts observed in US astronauts.

Main Methods:

• Review of recent reports on cataractogenesis and ionizing radiation.
• Analysis of preliminary serum data from atomic bomb survivors (Neriishi et al., 2003).
• Comparison of findings with cataract prevalence and biomarkers in US astronauts.

Main Results:

• Preliminary analysis of atomic bomb survivors showed statistically significant associations between persistent inflammation, calcium levels, and the dose response of PSC and cortical cataracts.
• These findings support the hypothesis linking cataractogenesis to intermediate variables like inflammation and calcium imbalance.
• Similarities in excess cataracts and serum biomarkers between atomic bomb survivors and astronauts suggest shared underlying mechanisms.

Conclusions:

• The proposed two-stage etiology of cataractogenesis is supported by preliminary data from atomic bomb survivors and astronauts.
• Intermediate risk factors, including inflammation and calcium dysregulation, are crucial for understanding ionizing radiation's cataractogenic effects.
• Further analysis of updated datasets, incorporating these intermediate factors and retinal/uveal pathologies, is necessary to validate these concepts.