The rtPA increases MMP-9 activity in serum during ischaemic stroke

To find the relationship between rtPA treatment vs. MMP-9 activity, MMP-3, and TIMP-1 serum levels related to patients' neurological status during acute ischaemic stroke (IS).

35 IS patients were enrolled. 14 of them underwent thrombolytic therapy with Actylise (rtPA group). The serum samples were obtained at 3 time-points for rtPA group (time-point 0: 1st-4th hour of stroke; time-point 1 - immediately after rtPA administration; time-point 2 - on day 5-7 from stroke onset). Remaining patients had venous blood collection at two time-points: time-point 1 - 5th-10th hour of stroke and time-point 2 - on day 5-7 of stroke. MMP-9 was analyzed with gelatin zymography, MMP-3 and TIMP-1 serum levels were analyzed with ELISA method. NIHSS improvement ratio (IR) was calculated as a difference between NIHSS score at the admission and discharge of patient.

The active form of MMP-9 (86kDa) was not observed in any analyzed samples. Total MMP-9 activity was significantly elevated at time-point 1 in rtPA group in comparison with non-rtPA group. MMP-3 serum level significantly decreased during rtPA administration in comparison with non-rtPA group and it was restored at time-point 2. MMP-3 negatively correlated with IR values (p=0.06).

Thrombolysis applied for IS treatment increases MMP-9 activity in serum, however, rtPA does not facilitate the conversion of pro-MMP-9 into the active form. Our results also suggest the involvement of MMP-3 to the biochemical processes occurring during acute phase of IS.