Matrix metalloproteinase (MMP)-9: A realiable marker for inflammation in early human trichinellosis

Serum samples from 31 Trichinella britovi-infected individuals (20 males and 11 females), living in Tuscany, Central Italy, were analysed for MMP-9 and MMP-2 serum levels. Patients acquired infection with Trichinella after consuming raw or undercooked meat of wild boar. Their median age was 49 ± 0.33 years (range from 7 to 91). Sera was collected before starting anti-inflammatory treatment, aliquoted and stored at −20 °C until use. Sera from healthy subjects was considered as controls. The gelatinolytic activity of MMPs was analysed by gelatin zymography on 8% polyacrylamide-SDS gels containing 0.1% porcine gelatin, under non-reducing conditions. Clear bands corresponding to the digested areas were evaluated with an appropriate software. MMP-9 levels were additionally determined in 15 patients using a commercial ELISA kit for human MMP-9. The zymographic analysis of the gels showed the presence in serum samples of gelatinase bands at approximately 125-kDa, 92-kDa and 72-kDa, corresponding to the MMP-9/Neutrophil gelatinase-associated lipocalin (NGAL) complex and proenzyme forms of MMP-9 and MMP-2, respectively. A significant (p < 0.01) increase in gelatinolytic activity in patients compared to the control group was observed for pro-MMP-9 in 25 out of 31. The mean increase in activity was 39.25% ± 16.67%. No significant differences were observed for pro-MMP-2 activity. The MMP-9 levels detected by ELISA showed significant correlation with zymographic data (r2 = 0.62, p < 0.003) and were higher in more affected patients (suffering diarrhea, facial edemas and myalgia). In conclusion, MMP-9 might be considered as a marker of inflammation in T. britovi patients. On the contrary, MMP-2 did not result significantly different in patients, compared to controls.