Extracellular phospholipase A2 expression in sarcoidosis.
This study was conducted in order to focus upon the Ca2- dependent secretory non-pancreatic phospholipase A2 (npPLA2) enzyme and its possible role in the pathophysiology of sarcoidosis. Serum samples were taken from 24 patients with sarcoidosis to determine the levels of npPLA2. Moreover, in another group of patients with active chest x-ray stage II and III sarcoidosis, bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial lung biopsies (TBL) were taken. Highly significant increase of npPLA2 in serum was found in patients compared to controls (p < 0.001). Furthermore, those patients with stable and inactive disease and those who were under treatment with corticosteroids, tended to have lower values than those with active disease and those who were untreated. An intense accumulation of npPLA2 was found in smooth muscle tissue in lung biopsy specimens, in close connection with fibroblast accumulation and deposition of collagen. These cells also stained positive for alpha-smooth muscle actin (alpha-SMA). In addition, when using the technique of in situ hybridization, expression of npPLA2-mRNA was found in the fibroblast layer surrounding the epitheloid cell granulomas. These fibroblasts did not stain positive for alpha-SMA. Our data suggest that npPLA2 is actively involved, and has an important role, in the pathophysiology of sarcoidosis.
Andersen
S
S
UNIGEN Centre for Molecular Biology, University of Trondheim, Norway.
Bjermer
L
L
Selbo
P K
PK
Dalaker
M
M
Johansen
B
B
D000199:Actins / Q000378:metabolism; D000328:Adult; D000368:Aged; D001706:Biopsy; D001992:Bronchoalveolar Lavage Fluid; D001999:Bronchoscopy; D004797:Enzyme-Linked Immunosorbent Assay; D005110:Extracellular Space / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism; D010741:Phospholipases A / Q000235:genetics / Q000378:metabolism*; D054467:Phospholipases A2; D012333:RNA, Messenger / Q000032:analysis; D017565:Sarcoidosis, Pulmonary / Q000201:enzymology* / Q000473:pathology
D000199:Actins; D012333:RNA, Messenger; D010741:Phospholipases A; D054467:Phospholipases A2