Fukuda Y, Ishizaki M, Kudoh S, Kitaichi M, Yamanaka N
Department of Pathology, Nippon Medical School, Tokyo, Japan.
Lab Invest. 1998 Jun;78(6):687-98.
In interstitial lung diseases, deposition of extracellular matrix (ECM) in alveoli and degradation of ECM lead to pulmonary structural remodeling. The changes in ECM and the localization of matrix metalloproteinases (MMPs) and a tissue inhibitor of metalloproteinases (TIMP) in the lung tissues of patients with bronchiolitis obliterans organizing pneumonia (BOOP) and idiopathic pulmonary fibrosis (IPF) were investigated. Immunohistochemical analysis for the detection of fibronectin, collagen-I, -III, and -IV, smooth muscle actin, MMP-1 (interstitial collagenase), -2 (gelatinase A), and -9 (gelatinase B), and TIMP-2, and in situ hybridization for the detection of MMP-9 mRNA were performed. Western blotting of lung tissue homogenates was performed for MMP-2 and MMP-9. The gelatinolytic activities of the homogenates were also determined using gelatin zymography. Fibronectin and collagen-I, -III, and -IV were detected in the intra-alveolar fibrosis in addition to the interstitium of these diseases. MMP-1, MMP-2, MMP-9, and TIMP-2 were detected in the regenerated epithelial cells covering intra-alveolar fibrosis. Myofibroblasts in intra-alveolar fibrosis in BOOP showed predominant reaction for MMPs, and they ultrastructurally appeared to be phagocytosing collagen fibrils, and those of IPF showed a predominant reaction for TIMP-2. New vascularization in intra-alveolar fibrosis was exclusively observed in cases of BOOP, and the endothelial cells were positive for MMP-2. Western blotting showed the existence of a latent form of MMP-9 and latent and active forms of MMP-2, and gelatin zymography revealed that the ratio of active/latent forms of MMP-2 in BOOP is significantly larger than that in the control lungs. Predominant MMPs in BOOP may constitute the mechanism of reversibility of fibrotic changes in this disease. TIMP-2 in myofibroblasts in IPF may contribute to the stable ECM deposition and the irreversible pulmonary structural remodeling.
在间质性肺疾病中，细胞外基质（ECM）在肺泡中的沉积以及ECM的降解会导致肺部结构重塑。研究了闭塞性细支气管炎伴机化性肺炎（BOOP）和特发性肺纤维化（IPF）患者肺组织中ECM的变化以及基质金属蛋白酶（MMPs）和金属蛋白酶组织抑制剂（TIMP）的定位。进行了免疫组织化学分析以检测纤连蛋白、I型、III型和IV型胶原、平滑肌肌动蛋白、MMP-1（间质胶原酶）、MMP-2（明胶酶A）和MMP-9（明胶酶B）以及TIMP-2，并进行了原位杂交以检测MMP-9 mRNA。对肺组织匀浆进行了MMP-2和MMP-9的蛋白质印迹分析。还使用明胶酶谱法测定了匀浆的明胶分解活性。除了这些疾病的间质外，在肺泡内纤维化中还检测到了纤连蛋白和I型、III型和IV型胶原。在覆盖肺泡内纤维化的再生上皮细胞中检测到了MMP-1、MMP-2、MMP-9和TIMP-2。BOOP中肺泡内纤维化的肌成纤维细胞对MMPs表现出主要反应，超微结构上它们似乎在吞噬胶原纤维，而IPF的肌成纤维细胞对TIMP-2表现出主要反应。仅在BOOP病例中观察到肺泡内纤维化中的新血管形成，并且内皮细胞对MMP-2呈阳性。蛋白质印迹显示存在MMP-9的潜伏形式以及MMP-2的潜伏和活性形式，明胶酶谱显示BOOP中MMP-2的活性/潜伏形式的比率明显高于对照肺。BOOP中主要的MMPs可能构成了该疾病纤维化改变可逆性的机制。IPF中肌成纤维细胞中的TIMP-2可能有助于稳定的ECM沉积和不可逆的肺部结构重塑。
