Leptin enhances peroxide production in human umbilical cord leucocytes

Abstract

We have used flow cytometry to assess the effect of human recombinant leptin on peroxide production by human umbilical leucocytes in cord blood from 12 normal newborns (seven females and five males). Peroxide production was determined by the oxidation of 2´. 7´ dichlorofluorescein diacetate (DCFH-DA) in the three cell populations studied. The cells were stimulated with an optimal and physiological concentration of leptin (10 ng/ml), which induced a constant and significant production of peroxide as compared to non-stimulated cells. There was a significant two-fold increase (P < 0.005) in peroxide formation at time points 10, 20 and 30 min for polymorphonuclear cells and lymphocytes. Monocytes, in very low number as compared to the other cell populations, were also activated by leptin. However, the effect on peroxide production was far below the amount observed when PMA was used as a stimulus (P < 0.00001). There was no significant correlation between the weight or sex of the newborn and the effect of leptin. Future studies should ascertain the role of this cytokine in cord blood cells.