Ulinastatin as a neuroprotective and anti-inflammatory agent in infant piglets model undergoing surgery on hypothermic low-flow cardiopulmonary bypass

Objective Infants are potentially more susceptible to brain injury mediated via cell death attributed to cardiopulmonary bypass (CPB) especially with prolonged hypothermic low flow (HLF). We hypothesized that a human urinary protease inhibitor (ulinastatin), by its anti-inflammatory effect, would reduce central nervous system (CNS) injury during HLF. Methods Fifteen general-type infant piglets were randomized to ulinastatin group (Group U, n=5), control group (Group C, n=5), and sham operation group (Group S, n=5). Routine CPB was established after median thoracotomy in Group U and C under anesthesia. When the temperature of infant piglets dropped down to 25 degrees C, low-flow CPB (50ml center dot kg1 center dot min1) was instituted. After 120min of aortic cross-clamping and 20- to 30-min rewarming, the aortic cross-clamp was removed and finally the piglet was weaned from CPB. Five thousand units per killogram of ulinastatin and equivalently normal saline were, respectively, given at the beginning of and at aortic declamping in Group U and Group C. Group S just received sham median thoracotomy. Venous blood samples were taken immediately after anesthesia induction in all three groups, 5- and 120-min post CPB in both Group U and C, respectively; plasma markers of inflammation and CNS injury were compared. Pathology results of hippocampus were observed by light microscopy. Results Statistically significant differences between Group C and U were noted in the expression of inflammatory markers such as IL-10, TNF- and neuron-specific enolase at 120-min post CPB. Brain injuries were observed in both groups (index cases and controls) and were milder in Group U. Conclusions In our study, HLF CPB on infant piglets resulted in brain injury, and ulinastatin might reduce the extent of such injury.