Arias-Diaz J, Garcia-Verdugo I, Casals C, Sanchez-Rico N, Vara E, Balibrea J L
Department of Surgery, Hospital San Carlos, Madrid, Spain.
Shock. 2000 Sep;14(3):300-6. doi: 10.1097/00024382-200014030-00010.
Surfactant protein A (SP-A) is thought to play a role in the modulation of lung inflammation during acute respiratory distress syndrome (ARDS). However, SP-A has been reported both to stimulate and to inhibit the proinflammatory activity of pulmonary macrophages (Mphi). Because of the interspecies differences and heterogeneity of Mphi subpopulations used may have influenced previous controversial results, in this study, we investigated the effect of human SP-A on the production of cytokines and other inflammatory mediators by two well-defined subpopulations of human pulmonary Mphi. Surfactant and both alveolar (aMphi) and interstitial (iMphi) macrophages were obtained from multiple organ donor lungs by bronchoalveolar lavage and enzymatic digestion. Donors with either recent history of tobacco smoking, more than 72 h on mechanical ventilation, or any radiological pulmonary infiltrate were discarded. SP-A was purified from isolated surfactant using sequential butanol and octyl glucoside extractions. After 24-h preculture, purified Mphi were cultured for 24 h in the presence or absence of LPS (10 microg/mL), SP-A (50 microg/mL), and combinations. Nitric oxide and carbon monoxide (CO) generation (pmol/microg protein), cell cGMP content (pmol/microg protein), and tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1, and IL-6 release to the medium (pg/microg protein) were determined. SP-A inhibited the lipopolysaccharide (LPS)-induced TNFalpha response of both interstitial and alveolar human Mphi, as well as the IL-1 response in iMphi. The SP-A effect on TNFalpha production could be mediated by a suppression in the LPS-induced increase in intracellular cGMP. In iMphi but not in aMphi, SP-A also inhibited the LPS-induced IL-1 secretion and CO generation. These data lend further credit to a physiological function of SP-A in regulating alveolar host defense and inflammation by suggesting a fundamental role of this apoprotein in limiting excessive proinflammatory cytokine release in pulmonary Mphi during ARDS.
表面活性蛋白A（SP-A）被认为在急性呼吸窘迫综合征（ARDS）期间肺部炎症的调节中发挥作用。然而，有报道称SP-A既能刺激也能抑制肺巨噬细胞（Mphi）的促炎活性。由于所用Mphi亚群的种间差异和异质性可能影响了先前有争议的结果，在本研究中，我们研究了人SP-A对两种明确的人肺Mphi亚群细胞因子和其他炎症介质产生的影响。通过支气管肺泡灌洗和酶消化从多个器官供体肺中获取表面活性剂以及肺泡（aMphi）和间质（iMphi）巨噬细胞。有近期吸烟史、机械通气超过72小时或任何肺部放射学浸润的供体被排除。使用丁醇和辛基葡糖苷顺序提取从分离的表面活性剂中纯化SP-A。经过24小时预培养后，纯化的Mphi在有或无脂多糖（LPS，10微克/毫升）、SP-A（50微克/毫升）及其组合的情况下培养24小时。测定一氧化氮和一氧化碳（CO）的生成量（皮摩尔/微克蛋白）、细胞cGMP含量（皮摩尔/微克蛋白）以及肿瘤坏死因子α（TNFα）、白细胞介素（IL）-1和IL-6释放到培养基中的量（皮克/微克蛋白）。SP-A抑制了脂多糖（LPS）诱导的间质和肺泡人Mphi的TNFα反应，以及iMphi中的IL-1反应。SP-A对TNFα产生的影响可能是通过抑制LPS诱导的细胞内cGMP增加来介导的。在iMphi而非aMphi中，SP-A还抑制了LPS诱导的IL-1分泌和CO生成。这些数据进一步证明了SP-A在调节肺泡宿主防御和炎症中的生理功能，表明这种载脂蛋白在ARDS期间限制肺Mphi中过度促炎细胞因子释放方面具有重要作用。
