Immunohistochemical evalution of the expression of MMP9, MMP2 and TIMP2 in venous leg ulcers before and after biomodulation with fluorescent light energy

Background and aim: The aim of the study was to evaluate immunohistochemically the expression of matrix metalloproteinases 2 and 9 (MMP-2, MMP-9) and MMP-inhibitor (TIMP-2) before and after fluorescence biomodulation treatment* in patients with venous leg ulcers.

Methods: We enrolled 24 patients (15 females, 9 males), divided in three groups: 5 patients were treated with standard of care, 10 patients with fluorescence biomodulation twice weekly and 9 patients with two consecutive biomodulation treatments once a week. We performed two punch biopsies from wound edge and wound bed at week 0, 8, 16 and 24 immunostained for MMP-9, MMP-2 and TIMP-2. The intensity and the percentage of positive cells were evaluated.

Results: MMP-2 mean level expression did not show any significant differences among all groups. MMP-9 mean level expression in the biopsies from the wound bed increased from baseline to V8 and V24 in the third group (33%, 35%, 45%). TIMP-2 expression was higher in the groups treated with fluorescence biomodulation treatment*: baseline mean value was 26% in the first group, 26% and 33% in the second and third respectively; at V8 the values were 33%, 40% and 35% respectively; at V24 mean values were 27% in the first group, 37 and 54% in the second and third respectively.

Conclusions: Our results suggest a role of the fluorescence biomodulation treatment* in the increase of tissue inhibitor and of MMP-9 that could lead to a matrix remodelling with a positive effect on healing processes.