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.