Fibroblast Growth Factor-2: A Promising Biomarker for Anxiety and Trauma Disorders.

Anxiety and trauma disorders are a significant source of global burden. Although it is clear that there is great heterogeneity in humans' response to trauma and stress, most research on fear and anxiety has focused on the "average" animal. Increased understanding of the sources of individual differences in fear reactions may lead to more refined means of predicting who is at risk for the development of anxiety disorders so that early preventative interventions can be implemented. This commentary highlights recent cross-species work (in rats and humans) indicating that the neurotrophin fibroblast growth factor-2 (FGF2) holds promise as a potential biomarker for anxiety disorder vulnerability. Both central (hippocampal) and peripheral (serum and saliva) markers of FGF2 correlate negatively with fear expression after an aversive conditioning experience. Here, 2 broad accounts of the potential mechanism of vulnerability captured by measures of FGF2 are outlined. In particular, it is suggested that basal differences in FGF2 (across different tissue types) may provide a general index of one's regenerative capacity; alternatively, differences in FGF2 reactivity (in specific tissue types) may be indicative of one's coping capacity in response to stress.