Background: Therapies for better donor maintenance should be studied to improve transplant outcome. In addition to inflammatory response, brain death (BD) induces microcirculatory alterations which result in organs hypoperfusion There is evidence that BD triggers platelet aggregation and thrombus formation. In this context, this study investigated the effect of thrombolytic alteplase (rTPA) and methylprednisolone therapy after BD in male rats.
Methods: Wistar rats were submitted to BD by the rapid inflation of an intracranial catheter, and maintained for 6 h. After 3 h of BD confirmation, rats were treated with rTPA and methylprednisolone (rTPA+P - 3 mg/kg; 20 mg/kg respectively, i.v for 30 minutes). Sham-operated (Sham) rats were used as controls. After 6h of BD, the animals were submitted to intravital microscopy of[Y1]  the mesentery. At the end of the experiment, blood samples were collected for platelet aggregation analysis, and thromboelastometry. Serum concentration of inflammatory mediators were measured by ELISA.
Results: The data on corticosterone serum concentrations [Y2] showed reduction on BD animals and increased values in the treated group (P = 0.002). There was a reduction of circulating platelet numbers after BD (P=0.007) which was also in the treated group (P = 0.044). [MV3] In parallel, we identified an increase of platelet aggregation after BD (P=0.005) and a reduction of rTPA+P (P = 0.09). Additionally, BD group presented a decrease in small vessels perfusion in comparison to Sham (P = 0.044). Treatment with rTPA+P restored perfusion and increased vessel density (P = 0.018). Despite the vascular effects observed, no differences were found in von Willebrand factor (vWF) [Y4] serum concentrations and nitrites and nitrates (NOx-)[Y5] . In relation to serum inflammatory mediators TNF-α and IL-6, there was an increase after 6 h of BD (TNF-α: P = 0.026; IL-6: P = 0.063), and the treated group presented lower mediators concentrations (TNF-α: P = 0.048; IL-6: P = 0.0009).
Conclusion: This study presents the effectiveness of alteplase associated with methylprednisolone administration in decreasing platelet aggregation, and improving microcirculatory perfusion and vessel density. It could be considered for further clinical analysis with the goal of improving donor maintenance and organ quality.