Surfactant subtypes. In vitro conversion, in vivo function, and effects of serum proteins.
Surfactant subtypes. In vitro conversion, in vivo function, and effects of serum proteins.
复制标题
表面活性剂亚型。
DOI：
10.1164/ajrccm.149.5.8173767
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发表时间：
1994
影响因子：
24.7
通讯作者：
Jobe,A
中科院分区：
文献类型：
--
作者：
Ueda,T;Ikegami,M;Jobe,A
肺泡腔中的表面活性剂可通过差速离心或等体积蔗糖密度梯度分为重亚型和轻亚型。从重亚型到轻亚型的转化通过表面积循环在体外发生。然而，循环产生的光亚型的功能和可能影响体外转化的物质尚未得到评估。因此，我们比较了从兔表面活性剂中分离的重亚型和轻亚型以及通过表面积循环体外制备的类似密度级分的体内功能。然后我们询问血清、球蛋白或白蛋白是否会改变体外转化。通过用 50 mg/kg 重亚型或轻亚型表面活性剂处理缺乏表面活性剂的 27 天胎龄早产兔，研究了表面活性剂组分的体内功能。 PV 曲线测量的动态顺应性值和肺容量表明，与轻亚型相比，重亚型具有优越的体内功能，与体内或体外来源无关（p < 0.01）。体外制备的轻亚型失去了表面活性剂功能并且与体内轻亚型相似。当血清蛋白添加到重亚型表面活性剂中时，重亚型向轻亚型的转化速度加快。血清比球蛋白加速转化，丝氨酸蛋白酶抑制剂二异丙基氟磷酸酯阻断该转化。白蛋白没有显着影响。血清引起的转化率增加确定了表面活性剂失活的新机制，这种失活可能发生在与肺泡蛋白增加相关的肺损伤中。
Surfactant in the alveolar space can be separated into heavy and light subtypes by differential centrifugation or on isopyknic sucrose density gradients. The conversion from heavy subtypes to light subtypes occurs in vitro by surface-area cycling. However, the function of light subtypes made by cycling and substances that might influence in vitro conversion have not been evaluated. Therefore, we compared the in vivo function of the heavy and light subtypes isolated from rabbit surfactant and similar density fractions prepared in vitro by surface-area cycling. We then asked if serum, globulin, or albumin would alter the in vitro conversion. The function of surfactant fractions was studied in vivo by treating surfactant-deficient 27 d gestational age preterm rabbits with 50 mg/kg of heavy or light subtype surfactant. Dynamic compliance values and lung volumes from PV curve measurements showed that heavy subtypes had superior in vivo function compared with light subtypes independent of in vivo or in vitro sources (p < 0.01). Light subtypes prepared in vitro lost surfactant function and were similar to in vivo light forms. When serum proteins were added to the heavy subtype surfactant, the conversion rate from heavy to light subtypes was accelerated. Serum accelerated conversion more than globulin, and the serine proteinase inhibitor diisopropylfluorophosphate blocked the conversion. Albumin had no significant effect. The increased rate of conversion caused by serum identifies a new mechanism for surfactant inactivation that could occur with lung injuries associated with increased alveolar protein.