Decreased MMP-9 production in primary progressive multiple sclerosis patients

An increase in MMP-9 levels has been found in relapsing-remitting (RR) multiple sclerosis (MS) showing correlation with magnetic resonance (MR) parameters mainly during relapses. However, data regarding primary progressive (PP) MS is scarce.

To determine both the pro and active forms of MMP-9 in PPMS and transitional progressive (TP) MS, RRMS and healthy controls (HC), and to assess the relationship between MMP-9 levels and clinical and radiological variables in PP/TPMS.

73 patients with PP/TPMS, 50 RRMS and 43 HC were studied. Levels of pro and active forms of MMP-9 in serum were measured with ELISA. EDSS and MSFC scores were recorded and T2- and T1-weighted MR scans were obtained at the time of blood sampling and one and two years later for PP/TP MS cases.

MMP-9 levels were 202.27 ng/ml for PP/TPMS, 242.20 ng/ml for RRMS and 274.49 ng/ml for HC. MMP-9 levels were significantly lower in PP/TPMS compared to RRMS (P= 0.026) and HC (P= 0.001). No significant correlations were found between MMP-9 levels and clinical scores or radiological parameters.

These results point to different regulatory mechanisms of MMP-9 production and/or activity between PP/TPMS and RRMS.