Remodeling of the pulmonary artery in idiopathic pleuroparenchymal fibroelastosis

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare subtype of idiopathic interstitial pneumonia that consists of alveolar septal elastosis and intra-alveolar collagenosis, which is predominantly located in the upper lobes. The aim of this study was to examine the remodeling of the pulmonary arteries in patients with IPPFE. This study included 18 patients with IPPFE, 24 patients with idiopathic pulmonary fibrosis (IPF), and 5 patients without pulmonary disease as controls. We selected muscular pulmonary arteries and calculated the percentage of the thickness of each layer of the wall (intima, media, and adventitia) in relation to the external diameter. We also quantified the percentage of areas of elastic fiber in the media divided by the whole area of the media (medial elastic fiber score). The percentage of adventitial thickness in IPPFE was significantly higher than that in IPF and in control lungs. The percentage of medial thickness did not differ statistically between IPPFE and IPF. However, the medial elastic fiber score in IPPFE was also significantly larger than that in IPF and control lungs. These results suggest that collagenous thickening of the adventitia and medial elastosis are distinct histological features in the muscular pulmonary arteries of patients with IPPFE.

特发性胸膜肺实质弹力纤维增生症（IPPFE）是特发性间质性肺炎的一种罕见亚型，由肺泡间隔弹力纤维增生和肺泡内胶原沉积组成，主要位于上叶。本研究的目的是检查IPPFE患者的肺动脉重塑情况。本研究纳入了18例IPPFE患者、24例特发性肺纤维化（IPF）患者以及5例无肺部疾病的患者作为对照。我们选取了肌性肺动脉，并计算了血管壁各层（内膜、中膜和外膜）厚度相对于外径的百分比。我们还量化了中膜内弹性纤维面积占中膜总面积的百分比（中膜弹性纤维评分）。IPPFE中外膜厚度百分比显著高于IPF和对照肺。IPPFE和IPF之间中膜厚度百分比无统计学差异。然而，IPPFE的中膜弹性纤维评分也显著高于IPF和对照肺。这些结果表明，外膜的胶原增厚和中膜的弹力纤维增生是IPPFE患者肌性肺动脉中独特的组织学特征。