Serine Protease Imbalance in the Small Airways and Development of Centrilobular Emphysema in Chronic Obstructive Pulmonary Disease.

Epithelial dysfunction in the small airways may cause the development of emphysema in chronic obstructive pulmonary disease. C/EBPα (CCAAT/enhancer binding protein-α), a transcription factor, is required for lung maturation during development, and is also important for lung homeostasis after birth, including the maintenance of serine protease/antiprotease balance in the bronchiolar epithelium. This study aimed to show the roles of C/EBPα in the distal airway during chronic cigarette smoke exposure in mice and in the small airways in smokers. In a model of chronic smoke exposure using epithelial cell-specific C/EBPα-knockout mice, significant pathological phenotypes, such as higher protease activity, impaired ciliated cell regeneration, epithelial cell barrier dysfunction via reduced zonula occludens-1 (Zo-1), and decreased alveolar attachments, were found in C/EBPα-knockout mice compared with control mice. We found that Spink5 (serine protease inhibitor kazal-type 5) gene (encoding lymphoepithelial Kazal-type-related inhibitor [LEKTI], an anti-serine protease) expression in the small airways is a key regulator of protease activity in this model. Finally, we showed that daily antiprotease treatment counteracted the phenotypes of C/EBPα-knockout mice. In human studies, CEBPA (CCAAT/enhancer binding protein-α) gene expression in the lung was downregulated in patients with emphysema, and six smokers with centrilobular emphysema (CLE) showed a significant reduction in LEKTI in the small airways compared with 22 smokers without CLE. LEKTI downregulation in the small airways was associated with disease development during murine small airway injury and CLE in humans, suggesting that LEKTI might be a key factor linking small airway injury to the development of emphysema.

Annual decline in arterial blood oxygen predicts development of chronic respiratory failure in COPD with mild hypoxaemia: A 6-year follow-up study.

BACKGROUND AND OBJECTIVE: Chronic respiratory failure (CRF) with hypoxaemia is an important pathophysiology in patients with chronic obstructive pulmonary disease (COPD), and existing mild hypoxaemia may be a sign of future CRF development. However, little is known about the trajectory of partial arterial pressure of oxygen (PaO2 ) decline in patients with COPD. We assessed decline in PaO2 and the impact of short-term reductions in PaO2 to predict future decline in PaO2 . METHODS: A total of 172 outpatients with COPD from a prospective cohort study were enrolled. Pulmonary function tests and arterial blood gas (ABG) analyses were conducted at baseline and 1 year after enrolment and changes in PaO2 (ΔPaO2 ) and other parameters were calculated. Survival and incidence of CRF (as assessed by prescription of long-term home oxygen therapy) were monitored for 6 years. RESULTS: A total of 164 patients completed the observation period and 101 patients had mild hypoxaemia (PaO2 < 80 Torr) at baseline. No patients with normal PaO2 (≥80 Torr) developed CRF, and 10 patients with mild hypoxaemia developed CRF in 6 years. Baseline airflow limitation and diffusion capacity were significantly associated with development of CRF. Receiver-operating characteristic curve analysis showed that ΔPaO2 of -3.05 Torr/year is a useful cut-off value to predict development of CRF in 6 years (hazard ratio (HR): 12.6, 95% CI: 3.48-58.73, P < 0.0001). CONCLUSION: Patients with COPD and mild hypoxaemia may benefit from repeat ABG after 1 year. Although PaO2 trajectories widely varied, significant annual changes in PaO2 of at least -3.0 Torr/year were predictive of CRF development.

Pericardial fluid is suitable as an alternative specimen for the measurement of ß-hydroxybutyrate within 96 h after death.

We examined postmortem ß-hydroxybutyrate (BHB) levels in the body fluids obtained from 253 forensic autopsy cases whose causes of death were determined. Postmortem changes of BHB levels according to postmortem intervals (PMI) in various body fluids (plasma, urine, vitreous humor, and pericardial fluids) were investigated to determine appropriate alternative specimens as plasma samples. Our study has indicated the following points: 1) the BHB levels in plasma specimens from three sampling sites showed no significant differences, 2) postmortem changes of BHB levels in plasma and pericardial fluids could be negligible within 96 h PMI, while urine and vitreous humor BHB levels showed postmortem changes, and 3) pericardial fluid would thus be most suitable as an alternative to plasma in postmortem BHB level. We have also proposed that BHB levels could be applicable for the diagnosis of metabolic disorders in forensic autopsy.

Diagnosis of fulminant type 1 diabetes mellitus in an autopsy case with postmortem changes.

A Japanese female in her thirties was found dead in her apartment; the postmortem interval was estimated to be approximately 3 days. Several postmortem changes were evident. Acute gastroenteritis had been diagnosed 3 days earlier. On autopsy, no specific findings other than fatty liver were observed. On hematoxylin eosin staining, mild fibrosis, and invasion of neutrophils in the pancreatic parenchyma, severe fatty liver, and extensive vacuolation of renal tubular cells were observed. Biochemical analyses revealed extremely high ß-hydroxybutyrate concentrations in body fluids with moderate elevation of hemoglobin A1c. Toxicological analyses of organ and urine samples were negative. We concluded that severe ketoacidosis had occurred in the deceased. Subsequently, selective destruction of pancreatic ß-cells was demonstrated. Considered together, results indicated that the cause of death was fulminant type 1 diabetes mellitus. This report illustrates the fact that a combination of biochemical and immunohistochemical investigations can be useful for diagnosing this condition in cases with evident postmortem changes.