FROM HEAD TO TOE: THE CELLULAR RESPONSE TO HEAVY ION EXPOSURE

INTRODUCTION As a prerequisite for developing appropriate countermeasures to mitigate acute effects and late radiation risks for the astronaut and thereby enabling long-term human space flight, the cellular radiation response to densely ionizing radiation needs to be better understood. The biological effectiveness of accelerated heavy ions with high linear energy transfer (LET) for effecting DNA damage response pathways as a gateway to cell death or survival is of major concern for space missions. As body tissues differ in their radiation sensitivity, the radiation response of different cell types such as kidney cells, osteoblasts, fibroblasts, lens epithelial cells and of eyes lenses in culture was analyzed. One Sentence Summary: The strong activation of pro-inflammatory signaling in human cells after heavy ion exposure might be a suitable target for countermeasure development

Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection

Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year)(1). Minor cervical traumas, infection, migraine and hypertension are putative risk factors(1-3), and inverse associations with obesity and hypercholesterolemia are described(3,4). No confirmed genetic susceptibility factors have been identified using candidate gene approaches(5). We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR(1)) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 x 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 x 10(-3); combined P = 1.00 x 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction(6-9). Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions

Genetic Risk Score for Intracranial Aneurysms: Prediction of Subarachnoid Hemorrhage and Role in Clinical Heterogeneity

Background: Recently, common genetic risk factors for intracranial aneurysm (IA) and aneurysmal subarachnoid hemorrhage (ASAH) were found to explain a large amount of disease heritability and therefore have potential to be used for genetic risk prediction. We constructed a genetic risk score to (1) predict ASAH incidence and IA presence (combined set of unruptured IA and ASAH) and (2) assess its association with patient characteristics. Methods: A genetic risk score incorporating genetic association data for IA and 17 traits related to IA (so-called metaGRS) was created using 1161 IA cases and 407 392 controls from the UK Biobank population study. The metaGRS was validated in combination with risk factors blood pressure, sex, and smoking in 828 IA cases and 68 568 controls from the Nordic HUNT population study. Furthermore, we assessed association between the metaGRS and patient characteristics in a cohort of 5560 IA patients. Results: Per SD increase of metaGRS, the hazard ratio for ASAH incidence was 1.34 (95% CI, 1.20-1.51) and the odds ratio for IA presence 1.09 (95% CI, 1.01-1.18). Upon including the metaGRS on top of clinical risk factors, the concordance index to predict ASAH hazard increased from 0.63 (95% CI, 0.59-0.67) to 0.65 (95% CI, 0.62-0.69), while prediction of IA presence did not improve. The metaGRS was statistically significantly associated with age at ASAH (β=-4.82×10-3per year [95% CI, -6.49×10-3to -3.14×10-3]; P=1.82×10-8), and location of IA at the internal carotid artery (odds ratio=0.92 [95% CI, 0.86-0.98]; P=0.0041). Conclusions: The metaGRS was predictive of ASAH incidence, although with limited added value over clinical risk factors. The metaGRS was not predictive of IA presence. Therefore, we do not recommend using this metaGRS in daily clinical care. Genetic risk does partly explain the clinical heterogeneity of IA warranting prioritization of clinical heterogeneity in future genetic prediction studies of IA and ASAH