Inflammatory response during cardiopulmonary bypass: neutrophil apoptosis

Cardiopulmonary bypass (CPB) is essential to open heart surgery. However, CPB induces many types of inflammatory response, and may contribute to the tissue injury and the development of postoperative complications. On the other hand, the neutrophil responses to injury and infection immediately and secretes elastases and cytokines followed by prolongation of inflammatory changes, and programmed cell death (apoptosis) of neutrophils is delayed by inflammatory response. In this study, we evaluated the alternation of the neutrophil life span during CPB. Peripheral blood was obtained from eight adult patients before CPB, 1 hr and 2 hr after CPB start. After separation of neutrophils, and incuvation in the presence of TNF-alpha for 3 hr, we measured fluorescence-microscopically apoptosis rate (%A). %A significantly decreased with time (before 9.7 +/- 2.3%, 1 hr 3.0 +/- 1.0%, 2 hr 1.5 +/- 0.6%, p < 0.05). We conclude that neutrophil apoptosis was suppressed significantly during CPB. Systemic inflammatory change induced by CPB may be prolonged with extended life span of neutrophil.