Autophagy, a process that helps maintain homeostatic balance between the synthesis, degradation, and recycling of organelles and proteins to meet metabolic demands, plays an important regulatory role in cellular senescence and differentiation. Here we examine the regulatory role of autophagy in idiopathic pulmonary fibrosis (IPF) pathogenesis. We test the hypothesis that epithelial cell senescence and myofibroblast differentiation are consequences of insufficient autophagy. Using biochemical evaluation of in vitro models, we find that autophagy inhibition is sufficient to induce acceleration of epithelial cell senescence and myofibroblast differentiation in lung fibroblasts. Immunohistochemical evaluation of human IPF biospecimens reveals that epithelial cells show increased cellular senescence, and both overlaying epithelial cells and fibroblasts in fibroblastic foci (FF) express both ubiquitinated proteins and p62. These findings suggest that insufficient autophagy is an underlying mechanism of both accelerated cellular senescence and myofibroblast differentiation in a celltype-specific manner and is a promising clue for understanding the pathogenesis of IPF. myofibroblast; p62; senescence
The outcome and cause of death of each lung disease directly associated with rheumatoid arthritis (RA-LD) have been poorly investigated.A retrospective study was conducted of 144 patients with RA-LD, in whom the median follow-up period after the initial visit for a respiratory examination was 4.5 yrs.A total of 57 patients were identified with usual interstitial pneumonia (UIP), 31 with bronchiectasis, 16 with nonspecific interstitial pneumonia (NSIP), 11 with bronchiolitis, five with organising pneumonia (OP), five with diffuse alveolar damage (DAD) and 19 with combined disease. The 5-yr survival rates were 36.6% in the UIP group, 87.1% in the bronchiectasis group, 93.8% in the NSIP group, 88.9% in the bronchiolitis group, 60.0% in the OP group and 20.0% in the DAD group. Survival of patients with DAD was worse than that of patients with UIP. Overall, survival of patients with UIP was worse than that of patients with bronchiectasis, NSIP or bronchiolitis. Of the 144 patients, 71 (49.3%) died, of whom 58 (81.7%) died due to respiratory lesions.Of patients with RA-LD, patients with DAD experienced the highest mortality, and the survival of patients with UIP was worse than that of patients with NSIP.
Three hundred and twenty autopsy cases of sarcoidosis during a 32 year period were collected from the Annuals of the Pathological Autopsy Cases in Japan, published yearly since 1958, and from a literature survey. A statistical analysis of these reviewed autopsy cases was carried out on the epidemiological features of the disease and on the causes of death.
The proportion of sarcoidosis autopsy cases relative to the total autopsy cases had increased during this 32 year period. The increase of sarcoidosis autopsies during this period was chiefly due to the increase in aged females; the total number of female cases was approximately two times more than that of males. As over half of the total cases had only a pathological diagnosis and not a clinical diagnosis for sarcoidosis, the actual morbidity from sarcoidosis that was estimated from the autopsy data and corrected by autopsy rate was over five times higher than that of the clinically recognized cases.
Age and sex distribution of these cases peaked in the thirties for both sexes, while another very high peak was noted in females over 50 years of age. In approximately 60% of the sarcoidosis autopsies, the cause of death related to sarcoid lesions in the heart, lung or nervous system, the majority of which involved cardiac sarcoidosis. In the remaining 40% of the cases, the cause of death was from non‐sarcoidosis diseases.
The findings suggest that the intrathoracic manifestations of IgG4-related lung disease develop through lymphatic routes of the lungs and show various clinical characteristics. Because some lymphoproliferative disorders show similar findings, the correlation of clinicoradiological and pathological characteristics is crucial for the diagnosis of IgG4-related lung disease.
AEF is an important smoking-related change in the lung that appears to correlate with the smoking history, and its distinction from UIP/P may be important.
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.
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