A recently published paper in Current Genomics details the drawbacks and benefits of using saliva for epigenetic studies specifically to assess adverse childhood experiences. According to the authors from the University of New Mexico, saliva, which is the most accessible biospecimen in children, can be used to identify changes correlated with experience and behavior.
The team investigated the impact of adverse childhood experiences (ACEs) on children aged four to eight over the course of six to eight months by collecting saliva at two time-points from children who had experienced traumatic events and from those who had not. Similarly saliva was collected at a single time point from children diagnosed with autism spectrum disorder (ASD) and normal children.
Using a bead-chip array technology, over 425,000 methylation sites were assayed for each child, providing insight into the methylation pattern for each child. Initial analysis showed that the children's methylation patterns did not cluster by diagnosis, experience, age, sex, or ethnicity.
The team reported that the children grouped most closely by the cellular composition of their saliva, whether it contained primarily cheek cells or white blood cells. By correcting for cell type composition using methylation data from purified cheek and blood cells, sites were found that differed significantly according to experience. These sites are involved in brain development, rather than the differences between cheek and blood cell differentiation. The scientists are now exploring markers within corrected datasets for both cohorts of children.