New insights on congenital pulmonary airways malformations revealed by proteomic analyses.

BACKGROUND: Congenital Pulmonary Airway Malformation (CPAM) has an estimated prevalence between 0.87 and 1.02/10,000 live births and little is know about their pathogenesis. To improve our knowledge on these rare malformations, we analyzed the cellular origin of the two most frequent CPAM, CPAM types 1 and 2, and compared these malformations with adjacent healthy lung and human fetal lungs. METHODS: We prospectively enrolled 21 infants undergoing surgical resection for CPAM. Human fetal lung samples were collected after termination of pregnancy. Immunohistochemistry and proteomic analysis were performed on laser microdissected samples. RESULTS: CPAM 1 and 2 express mostly bronchial markers, such as cytokeratin 17 (Krt17) or α-smooth muscle actin (ACTA 2). CPAM 1 also expresses alveolar type II epithelial cell markers (SPC). Proteomic analysis on microlaser dissected epithelium confirmed these results and showed distinct protein profiles, CPAM 1 being more heterogeneous and displaying some similarities with fetal bronchi. CONCLUSION: This study provides new insights in CPAM etiology, showing clear distinction between CPAM types 1 and 2, by immunohistochemistry and proteomics. This suggests that CPAM 1 and CPAM 2 might occur at different stages of lung branching. Finally, the comparison between fetal lung structures and CPAMs shows clearly different protein profiles, thereby arguing against a developmental arrest in a localized part of the lung.

Bronchoalveolar cytology for diagnosing pulmonary GVHD after bone marrow transplant in children.

BACKGROUND: Cytological composition of bronchoalveolar lavage (BAL) fluid in pediatric bone marrow transplant (BMT) recipients with pulmonary complications has not been comprehensively described and BAL specific markers of pulmonary GVHD are lacking. The aim of this retrospective study was to assess the role of BAL in the diagnosis of pulmonary GVHD by comparing BAL cytological findings between pediatric allogenic BMT patients with pulmonary complications and oncology children receiving chemotherapy alone. METHODS: Retrospective analysis of BAL specimens for cytology, total and differential cell counts and presence of infections. RESULTS: Seventeen BMT and 13 chemotherapy BAL were analyzed. BAL total cell count was increased but similar between groups (96.9 x 10(4) vs. 98.2 x 10(4), P = NS). BAL cellular composition differed considerably between groups with a significantly higher number of lymphocytes (18% vs. 6.25%, P = 0.03) and a significantly lower number of neutrophils (25.9% vs. 58%, P = 0.02) in BMT BAL specimens. Atypical epithelial cells were significantly more frequent (75% vs. 30.8%, P = 0.027), and significantly more severe (P = 0.01) in BMT patients. The presence and severity of atypia was not associated with infection or pneumotoxic drug exposure (P = NS). CONCLUSION: BAL cytology differs significantly between BMT and chemotherapy patients. The presence BAL lymphocytosis and severe epithelial cell atypia concomitantly to respiratory symptoms and GVHD in other organs may suggest the diagnosis of pulmonary GHVD. Prospective studies assessing the reliability of this finding combined with markers such as epithelial cell apoptosis and increased cytokines are needed.

Hyperoxia increases leptin production: a mechanism mediated through endogenous elevation of corticosterone.

Leptin, a cytokine involved in the regulation of food intake, has been reported to be decreased in lung diseases such as chronic obstructive pulmonary disease and cystic fibrosis and increased in critically ill patients with sepsis. We investigated the role of leptin during hyperoxia in mice, which results in alveolar edema, severe weight loss, and death within 3-4 days. In oxygen-breathing mice, serum leptin was increased six- to sevenfold and its mRNA was upregulated in white adipose tissue. Leptin elevation could not be attributed to changes in circulating tumor necrosis factor-alpha but was completely dependent on endogenous corticosterone elevation because adrenalectomized mice did not exhibit any increase in leptin levels. Using leptin-deficient mice and wild-type mice treated with anti-leptin antibody, we demonstrate that weight loss was leptin independent. Lung damage was moderately attenuated in leptin-deficient mice but was not modified by anti-leptin antibody or leptin administration, suggesting that leptin does not play an essential role in the direct and short-term effects of oxygen-induced injury.