Elimination of reperfusion-induced microcirculatory alterations in vivo by adipose-derived stem cell supernatant without adipose-derived stem cells.

Background: In the present study, the authors hypothesized that adipose-derived stem cells in cell culture may secrete multiple cytokines in the supernatant, which might have a significant impact in vivo on the reperfusion-induced microcirculatory alterations and endothelial dysfunction.

Methods: Fat tissue was surgically harvested from rat flanks and processed for adipose-derived stem cell isolation; cells (1 × 10(6)) were subcultured for 3, 6, 9, and 12 days without passage. The postcultivated medium was harvested with medium change every 3 days. After centrifugation, the supernatant was collected and stored at -20°C. Supernatant collected on day 9 was analyzed for eight oxidative stress cytokines by an enzyme-linked immunosorbent assay strip. The effect of the supernatant on the reperfusion-induced microcirculatory alterations was examined in the vascular pedicle of isolated rat cremaster muscles subjected to 4 hours of ischemia followed by 2 hours of reperfusion.

Results: Enzyme-linked immunosorbent assay results demonstrated that adipose-derived stem cells produced several highly expressed cytokines in the supernatant. The average concentration of interleukin-6, in particular, was 5-fold higher compared with control. The reperfusion-induced vasospasm, arteriole stagnation, and the capillary no-reflow that often appear in the early phase of reperfusion were eliminated by adipose-derived stem cell supernatant.

Conclusions: Adipose-derived stem cells in cell culture display cytokine secretory properties that enable the cells to act through paracrine signaling. The supernatant even without cells could be used as a paracrine agent to interfere with the reperfusion-induced microcirculatory alterations and endothelial dysfunction.