Pleuroparenchymal fibroelastosis (PPFE) is a rare pulmonary fibrosis that is clinically characterized by upper-lobe predominant fibrosis. PPFE is a slowly progressive disorder and its first symptom is dyspnea or dry cough. Chest pain because of pneumothorax may be the first symptom in some patients. Patients with PPFE are slender with a flat rib cage or abnormally narrowed anterior–posterior thoracic dimension. Decreases in forced vital capacity, total lung capacity, and diffusing capacity are respiratory-function characteristics of PPFE, similar to those seen in idiopathic pulmonary fibrosis (IPF). The most remarkable difference in clinical features between PPFE and IPF is imaging findings, with upper-lobe-predominant lesions in PPFE and lower-lobe-predominant lesions in IPF.

Although previous authors have reported single data point, yearly changes in respiratory function have not been examined in combined pulmonary fibrosis and emphysema (CPFE). To quantify the annual changes in respiratory function of patients with CPFE and to examine the difference in survival between CPFE patients and patients with idiopathic pulmonary fibrosis without emphysema (IPF alone), 26 patients with CPFE and 33 IPF alone patients, whose respiratory function had been monitored for at least a year, were selected. The baseline of vital capacity percent predicted (VC% pred) in CPFE patients was greater than that in IPF-alone patients (86.6+/-24.0% vs. 72.8+/-19.4%, p=0.018). The annual decrease in VC% pred was significantly less in CPFE patients than in IPF-alone patients (-1.2+/-4.8% vs. -8.0+/-7.4%, p<0.001). Baseline ratio of forced expiratory volume in one second to forced vital capacity (FEV(1)/FVC%) in CPFE patients was lower than that in IPF-alone patients (76.6+/-8.5% vs. 85.2+/-6.7%, p<0.001). In the CPFE group, FEV(1)/FVC% tended to decrease with time (-0.5+/-2.2% per year), but, in contrast, it increased in IPF-alone patients (+1.1+/-3.4% per year) (p=0.036). Baseline of diffusing capacity percent predicted (DLco% pred) was significantly lower in CPFE patients than in IPF-alone patients (45.3+/-15.0% vs. 60.7+/-19.8%, p=0.003). The annual decrease in DLco% pred was lower in CPFE patients than in IPF-alone patients (-3.7+/-7.9% vs. -10.7+/-8.8%, p=0.042). There was no significant difference in the survival duration between 26 CPFE and 33 IPF-alone patients according to Kaplan-Meier analysis. Ventilatory and gas-exchange deterioration during the course of IPF became mild when emphysema was coexistent.

Three major MAP kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38 kinase (p38 MAPK), are involved in the regulation of lung inflammation and injury. This study investigated whether MAPKs are activated and associated with lung injury in lung tissues from patients with idiopathic pulmonary fibrosis (IPF). The expression of the active ERK, JNK, and p38 MAPK was examined using western blot analysis and immunohistochemistry and apoptosis was also examined by the TUNEL method, in lung tissues from ten patients with IPF obtained by thoracoscopic biopsy and in eight normal lung parenchyma specimens obtained by lobectomy for lung cancer. Activated MAPKs are significantly increased in lung homogenates from patients with IPF compared with controls. Activated ERK in epithelial and endothelial cells, but not in fibroblasts or smooth muscle cells, was decreased, accompanied by the progression of fibrosis. Activated JNK in epithelial and endothelial cells, but not in fibroblasts, was increased, accompanied by the progression of fibrosis. Activated p38 MAPK in epithelial, endothelial, smooth muscle cells, and fibroblasts was increased at the intermediate stage of fibrosis, in which the TUNEL-positive cells were predominantly detected. This is the first study to suggest that MAPKs may be associated with the regulation of inflammation and lung injury in IPF.

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Low BMI, decreased FVC and increased RV/TLC in PPFE may be related to the progression of flattened chest cage which impairs distension of chest cage at inspiration. Elevated serum levels of KL-6 suggest a poor prognosis of PPFE.