Release of superoxide dismutase activity from human umbilical veins by heparin

OBJECTIVE: This study evaluated Superoxide dismutase activity released from human umbilical veins incubated with different doses of heparin and examined at different time points. STUDY DESIGN: Umbilical veins of fresh cords from full term babies were incubated with 175 or 1 U/ml of heparin at one end while the other end was incubated without heparin as control. Specimens were obtained at 10 minutes and 24 hours (high-dose) or at 10 minutes and 60 minutes (low-dose). Superoxide dismutase activity was measured by the cytochrome c method. Results were analyzed using Student's paired/test. RESULTS: A time-dependent release of superoxide dismutase activity into the buffer was observed in both heparin specimens as well as in control specimens. The difference in release in the presence of heparin was of statistical significance, compared with the controls. CONCLUSION: Because heparin is routinely used as an anticoagulant to maintain the patency of umbilical catheters, we conclude that this usage may alter a newborn's response to oxygen free radical damage by changes in superoxide dismutase activity.