“We have, for the first time, successfully been able to illustrate a relationship between the clinical response to serotonergic medication in patients with depression and the serotonin transporters in the brainstem and other regions of the brain,” says Kasper. PET allows the density of the serotonin transporters, the target binding site for SSRIs, to be quantified in certain core areas of the brainstem known as raphe nuclei.
Patients with depression who were enrolled in the study were examined before and after treatment with SSRIs. It was possible to demonstrate that the effectiveness of therapy correlated just a few weeks after the start of treatment with quantitative serotonin transporter values determined before treatment. Key to these new research findings were the development of new evaluation strategies for the PET data in the team led by Rupert Lanzenberger, and the synthesis of a highly specific and selective radioligand in the team led by Wolfgang Wadsak and Markus Mitterhauser.
The PET method, says Kasper, means that the occupation of the serotonin transporter by SSRIs in various regions of the patients’ brains can be quantified: “This represents a crucial step towards personalised therapy that goes way beyond the measurement of plasma concentrations”.
“Prediction of SSRI treatment response in major depression based on serotonin transporter interplay between median raphe nucleus and projection areas.” R. Lanzenberger, G.S. Kranz, D. Haeusler, E. Akimova, M. Savli, A. Hahn, M. Mitterhauser, C. Spindelegger, C. Philippe, M. Fink, W. Wadsak, G. Karanikas, S. Kasper. Neuroimage. 2012 Nov 1;63(2):874-81. doi: 10.1016/j.neuroimage.2012.07.023.