Perioperative Changes Of Human β-defensin 2 In Infants With Cardiopulmonary Bypass

Background Correcting heart defects with cardiopulmonary bypass (CPB) is the most effective treatment for congenital heart disease. Cardiac surgery with CPB provokes a systemic inflammatory response by activation of inflammatory cells and body fluid components. This inflammatory reaction may contribute to the development of postoperative complications, including acute pulmonary injury, myocardial dysfunction and postoperative infection. Therefore, it is of crucial importance to prevent and treat the inflammatory reaction for reducing postoperative complications, improving surgical outcome, and decreasing medical cost. Defensins are cationic antimicrobial peptides with six cysteine and three pairs of disulfide bonds, including a-defensin andβ-defensin. They are expressed mainly in a variety of epithelial tissues and myeloid cells. In addition to their antimicrobial activity in the initial defense against invading microorganisms, defensins show chemotactic activity for monocytes, immature dendritic cells, and memory T cells, thereby linking innate immunity and adaptive immunity.β-defensin (hBD-2) is epithelium-derived and an inducible antimicrobial peptide in pulmonary epithelium, the expression of with can be induced by infection and proinflammatory factors. Studies have shown that there is closely relationship between the expression level of hBD-2 after operative and the incidence of infection. Our study had shown that hBD-2 could regulate the inflammatory response in critical patients, and that the plasma level of hBD-2 is related to the outcome of such patients. However, we still do not know whether the CPB could influence the expression level of hBD-2.Objective This study was designed to investigate the effects of cardiopulmonary bypass on the expression of hBD-2 in infant children.Methods We continuously selected 110 infants with congenital heart disease aged< 1 year and weighing< 10 kg, who underwent open heart surgery requiring hypothermia CPB, and postoperatively used synchronized intermittent mandatory ventilation plus pressure assist-control ventilation. Plasma and bronchoalveolar lavage fluid level of hBD-2 were measured at pre-CPB, termination of CPB, and at 0,12 and 24 hours after operation. Correlation analysis was performed to define the relationship between the hBD-2 and the inflammatory response.Results (1) There were no significant change of plasmaβ-defensin 2 levels during cardiopulmonary bypass in infants. (2)β-defensin 2 levels in bronchoalveolar lavage fluid after the CPB and even after the operative were significantly higher than that before the CPB.Conclusionβ-defensin 2 increases in bronchoalveolar lavage fluid during and after caediopulmonary bypass, however, it is not effected significantly change in the plasma in infants.