Mariassy A T, Glassberg M K, Salathé M, Maguire F, Wanner A
Department of Medicine, University of Miami School of Medicine, Florida 33140, USA.
Am J Physiol. 1996 Jan;270(1 Pt 1):L54-61. doi: 10.1152/ajplung.1996.270.1.L54.
Airway smooth muscle tone and growth is regulated by endothelin-1 (ET-1), but the sources of ET-1 in the airway wall have not been clearly defined. We therefore wished to estimate the relative contributions of the epithelium and endothelium to ET-1 production in the bronchi (mean ID 1.7-4.9 mm) of mature normal sheep. Morphometric assessment of bronchial cross-sections revealed a number of epithelial cells three times greater than endothelial cells by direct cell count. In contrast, the overall cell surface density was five to six times greater, and the airway smooth muscle-centered cell surface density was three to four times greater for endothelial cells than for epithelial cells. The expression of preproendothelin-1 mRNA was detected in cultured aortic endothelial cells (as a substitute for bronchial endothelial cells) but not in cultured bronchial epithelial cells, and the former secreted seven times more immunoreactive ET-1 than the latter. These findings show that topographically the endothelium is better positioned for the regulation of ovine bronchial smooth muscle than the epithelium. Furthermore, the findings suggest greater constitutive ET-1 secretion by cultured endothelium than by epithelium.
气道平滑肌张力和生长受内皮素 -1（ET -1）调节，但气道壁中ET -1的来源尚未明确界定。因此，我们希望评估成熟正常绵羊支气管（平均内径1.7 - 4.9毫米）中上皮细胞和内皮细胞对ET -1产生的相对贡献。支气管横截面的形态计量学评估显示，通过直接细胞计数，上皮细胞数量比内皮细胞多两倍。相反，内皮细胞的总体细胞表面密度大五到六倍，以气道平滑肌为中心的细胞表面密度比上皮细胞大三到四倍。在培养的主动脉内皮细胞（作为支气管内皮细胞的替代物）中检测到前内皮素 -1 mRNA的表达，但在培养的支气管上皮细胞中未检测到，并且前者分泌的免疫反应性ET -1比后者多六倍。这些发现表明，从拓扑结构上看，内皮细胞比上皮细胞更适合调节绵羊支气管平滑肌。此外，这些发现表明培养的内皮细胞比上皮细胞具有更高的组成性ET -1分泌。
