Insulin-like Growth Factors may be Markers of both Traumatic Brain Injury and Fear-Related Stress

Insulin-like growth factors (IGF) are potent neurotrophic and neurorepair that were recently proposed as biomarkers of traumatic brain injury (TBI) associated psychiatric comorbidities, in particular post-traumatic stress disorder (PSTD). We tested the hypothesis IGF system is differentially deregulated acute early chronic stages TBI, under stress. Plasma IGF1 IGF2 levels evaluated mice 3 weeks days after a controlled cortical impact (CCI)-induced mild-to-moderate TBI. The effects conditioned fear on its interaction with TBI (TBI followed, later, by fear-inducing procedures) also evaluated. In plasma, decreased post-TBI only (−9%), whereas remained unaffected. brain, increased cortex hippocampus at (up to +650%). At days, surpringly, this increase was more diffuse important sham (craniotomized) animals. Additionally, immunostaining ventricles reorganized animals both stages. Conditioned exposure did not influence plasma levels, but reduced (−6%) levels. It dampened systems, level tissue distribution statistically different from controls these conditions. co-exposed animals, DNA methylation hippocampal Igf1 gene promoter. These results show blood most phase stressful event, up-regulated so phase.