Possible Association between Serum Matrix Metalloproteinase-9 (MMP-9) Levels and Relapse in Depressed Patients following Electroconvulsive Therapy (ECT)

Background Matrix metalloproteinases are involved in neuroinflammatory processes, which could underlie depression. Serum levels of MMP-9 and MMP-2 in depressed patients are significantly altered following electroconvulsive therapy, but an association between altered matrix metalloproteinases after successful ECT and possible relapse has yet to be investigated. Methods Serum was obtained twice, before and immediately after a course of electroconvulsive therapy, from 38 depressed patients. Serum was also collected, once, from two groups of age- and gender-matched healthy controls, 40 volunteers in each group. Possible associations between levels of matrix metalloproteinases and relapse during a 1-year follow-up period were analyzed. Results Excluding patients who did not respond to electroconvulsive therapy and patients lost to follow-up, data from 28 patients were evaluated. Eighteen of the patients (64.3%) relapsed within 1 year. In the group that did not relapse, serum levels of MMP-9 were significantly decreased after a course of electroconvulsive therapy, but not in the group that relapsed. No association between MMP-2 and relapse was observed. Conclusion The degree of change in serum MMP-9 change could be associated with relapse following electroconvulsive therapy in depressed patients.