title: Overexpression of matrix metalloproteinases in lung tissue of patients with primary spontaneous pneumothorax.
abstract: BACKGROUND
  Although blebs and bullae are frequently found in the apexes of lungs of patients with primary spontaneous pneumothorax (PSP), its pathogens remain unclear.
  
  
  OBJECTIVE
  To examine the role of proteases [matrix metalloproteinase (MMP)-2, MMP-7 and MMP-9] and antiproteases [tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2, TIMP-3 and TIMP-4] in the pathogenesis of PSP.
  
  
  METHODS
  Fifty consecutive PSP patients who received standard surgical care were enrolled in the study. Lung tissues from 20 patients with stage I non-small cell lung cancer were used as a control. Immunohistochemistry (IHC), reverse transcription-polymerase chain reaction (RT-PCR) and gelatin zymography were used to evaluate the expression of MMP and TIMP in the lung tissue of patients with PSP.
  
  
  RESULTS
  Overexpression of MMP-2, MMP-7 and MMP-9 was found in the afflicted lung by IHC, zymography and RT-PCR. By IHC, higher expression of MMP-2 and MMP-9 in PSP patients was identified in alveolar macrophages and type II pneumocytes (88 and 92% of patients in macrophages, and 72 and 70% of patients in type II pneumocytes, respectively). MMP-2, MMP-7 and MMP-9 expression in patients was higher in mesothelial cells (66, 76 and 76%). Overexpression of TIMP-2 was detected in the extracellular matrix around bullae and blebs. Expression levels of TIMP-1, TIMP-3 and TIMP-4 were negligible (<10% of cells) in both PSP patients and controls.
  
  
  CONCLUSIONS
  MMP-2, MMP-9, MMP-7 and TIMP-2 were upregulated in PSP lesions. These results suggest that an imbalance between the expression of proteases and antiproteases may be involved in the pathogeneses of PSP.
authors.affiliation: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Chien-Kuang
authors.initials: CK
authors.lastname: Chen
authors.forename: Pin-Ru
authors.initials: PR
authors.lastname: Chen
authors.forename: Hsu-Chih
authors.initials: HC
authors.lastname: Huang
authors.forename: Yu-Sen
authors.initials: YS
authors.lastname: Lin
authors.forename: Hsin-Yuan
authors.initials: HY
authors.lastname: Fang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics* / Q000378:metabolism*; D011030:Pneumothorax / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D020782:Matrix Metalloproteinases