Salvesen Bodil, Fung Michael, Saugstad Ola D, Mollnes Tom E
Institute of Immunology and Department of Pediatric Research, University of Oslo and Rikshospitalet University Hospital, Oslo, Norway.
Pediatrics. 2008 Mar;121(3):e496-505. doi: 10.1542/peds.2007-0878. Epub 2008 Feb 25.
Meconium aspiration syndrome has a complex, poorly defined pathophysiology. Meconium is a potent activator of complement in vitro and in vivo; the latter is associated with a systemic inflammatory response. The complement system and Toll-like receptors are 2 important upstream components of the innate immune system that act partly independently in the inflammatory network. The aim of this study was to investigate the relative role of complement and CD14 in meconium-induced cytokine production.
Human adult (n = 6) and cord whole blood (n = 6) anticoagulated with lepirudin was collected and distributed into tubes that contained inhibitory antibodies (anti-CD14, anti-C2, anti-factor D, or combinations thereof). The tubes were preincubated for 5 minutes before addition of meconium or buffer and then incubated for 4 hours at 37 degrees C. Complement activation was measured by quantification of the terminal sC5b-9 complement complex by enzyme-linked immunosorbent assay. A panel of 27 inflammatory mediators (cytokines, chemokines, and growth factors) was measured by using multiplex technology.
Fourteen of the 27 mediators measured were induced by meconium both in cord and adult blood. In cord blood, 2 additional chemokines were induced and the inflammatory response was, in general, more potent. Blocking of complement or CD14 differentially reduced the formation of most mediators, anti-CD14 being more effective. Notably, the combined inhibition of complement and CD14 almost completely abolished meconium-induced formation of the cytokines and the chemokines and markedly reduced the formation of growth factors. The endogenous lipopolysaccharide content of meconium could not explain the CD14-mediated response.
Meconium-induced triggering of the cytokine network is differentially mediated by complement and CD14. A combined inhibition of these effector mechanisms may be an alternative approach to reduce the inflammatory reaction in meconium aspiration syndrome.
胎粪吸入综合征具有复杂且定义不清的病理生理学机制。胎粪在体外和体内均是补体的强效激活剂；后者与全身炎症反应相关。补体系统和Toll样受体是天然免疫系统的两个重要上游成分，它们在炎症网络中部分独立发挥作用。本研究的目的是探讨补体和CD14在胎粪诱导的细胞因子产生中的相对作用。
收集用比伐卢定抗凝的成人全血（n = 6）和脐血（n = 6），并分装到含有抑制性抗体（抗CD14、抗C2、抗因子D或其组合）的试管中。在加入胎粪或缓冲液之前，将试管预孵育5分钟，然后在37℃孵育4小时。通过酶联免疫吸附测定法定量末端sC5b-9补体复合物来测量补体激活。使用多重技术测量一组27种炎症介质（细胞因子、趋化因子和生长因子）。
所测量的27种介质中有14种在脐血和成人血液中均由胎粪诱导产生。在脐血中，另外诱导产生了2种趋化因子，并且炎症反应总体上更强。补体或CD14的阻断不同程度地减少了大多数介质的形成，但抗CD14更有效。值得注意的是，补体和CD14的联合抑制几乎完全消除了胎粪诱导的细胞因子和趋化因子的形成，并显著减少了生长因子的形成。胎粪中的内源性脂多糖含量无法解释CD-介导的反应
胎粪诱导的细胞因子网络触发由补体和CD14不同程度地介导。联合抑制这些效应机制可能是减少胎粪吸入综合征炎症反应的一种替代方法。
