LAUSR

BACKGROUND Exposure to traumatic events is a risk factor for negative physical and mental health outcomes. However, the underlying biological mechanisms that perpetuate these lasting effects are not known. METHODS We investigated the impact and timing of sexual trauma, a specific type of interpersonal violence, experienced during key developmental windows of childhood, adolescence, or adulthood on adult health outcomes and associated biomarkers, including circulating cell-free mitochondrial DNA levels and extracellular vesicles (EVs), in a predominantly Black cohort of women (N = 101). RESULTS Significant changes in both biomarkers examined, circulating cell-free mitochondrial DNA levels and EV proteome, were specific to developmental timing of sexual trauma. Specifically, we identified a large number of keratin-related proteins from EVs unique to the adolescent sexual trauma group. Remarkably, the majority of these keratin proteins belong to a 17q21 gene cluster, which suggests a potential local epigenetic regulatory mechanism altered by adolescent trauma to impact keratinocyte EV secretion or its protein cargo. These results, along with changes in fear-potentiated startle and skin conductance detected in these women, suggest that sexual violence experienced during the specific developmental window of adolescence may involve unique programming of the skin, the body's largest stress organ. CONCLUSIONS Together, these descriptive studies provide novel insight into distinct biological processes altered by trauma experienced during specific developmental windows. Future studies will be required to mechanistically link these biological processes to health outcomes.