Transient increase in circulating myeloid-derived suppressor cells after partial bladder outlet obstruction.

PURPOSE: Partial bladder outlet obstruction causes a significant increase in tissue and systemic oxidative stress markers and tissue inflammatory cytokine levels. Myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone are believed to be associated with oxidative stress and inflammation. We investigated alterations in plasma myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone levels in partial bladder outlet obstruction and after its reversal. MATERIALS AND METHODS: Rats with surgically induced partial bladder outlet obstruction were divided into 4 groups of 3 each, including sham treated, 4-week obstruction, and 4 and 8-week obstruction with relief. Plasma levels of circulating myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone were assessed by flow cytometry or enzyme-linked immunosorbent assay. RESULTS: The circulating myeloid-derived suppressor cell level was markedly increased in the obstruction group compared to the sham treated group and it returned to normal in the 4 and 8-week obstruction with relief groups. Plasma IFN-γ, IL-10 and aldosterone were similarly increased in the obstruction group and returned to normal in the 4 and 8-week obstruction with relief groups. CONCLUSIONS: Levels of circulating myeloid-derived suppressor cells, IFN-γ, IL-10 and aldosterone were increased in rats with partial bladder outlet obstruction but returned to normal after reversal. This suggests that an increase in these parameters may be a good predictive indicator of patients at increased risk for urinary symptoms.