Human adult mesenchymal stem cells improve rat spatial cognitive function after systemic hemorrhagic shock

The aim of the present study was to examine whether a single infusion of human adult mesenchymal stem cells (hMSC) has protective effects on rat cognitive functions after systemic hemorrhagic shock. Systemic hemorrhagic rat shock model of pronounced (30 min) systemic hypotension [30-40 mmHg mean arterial blood pressure (MABP) reduction] was used to induce cerebral oligemia. Immediately after the experimental transient hypotension period ended, human processed lipoaspirate-derived mesenchymal stem cells (hMSC, 1 x 10(6)) were administered via the femoral vein. Rats were tested in relation to their cognitive spatial abilities using the Morris water maze before and 3 days after transient oligemia and with/without hMSC transplantation. Immunohistological investigations were performed with respect to apoptosis and BrdU staining. A clear functional improvement was observed in the rats' spatial cognitive abilities after hypotension and subsequent hMSC transplantation. In the hypotension group, hMSC infusion reduced the mortality from 50% to 25%. Six days after hMSC administration and hypotension, we did not detect any BrdU-labeled cells in rat brain, lung, and liver; however, BrdU-positive cells were found in spleen. No signs of cerebral apoptosis were observed. We conclude from this study that hMSCs derived from peripheral blood could be an important cell source to improve functional outcome after transient cerebral oligemia. Identifying the underlying mechanism for this, however, should be the subject of further investigations.