The expression of cyclooxygenase-1, cyclooxygenase-2 and 5-lipoxygenase in inflammatory muscle tissue of patients with polymyositis and dermatomyositis.
OBJECTIVE
To describe cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) expression in muscle tissue in patients with idiopathic inflammatory myopathies (IIM) - dermatomyositis (DM) and polymyositis (PM) and to find out if any differences between affected and non-affected muscles detected by MRI exist.


METHODS
Samples of muscle tissue from 7 patients with dermatomyositis (DM) and from 4 with polymyositis (PM) were obtained by needle biopsy from affected and non-affected sites distinguished by magnetic resonance imaging. In situ hybridization with antisense mRNA probes was employed to detect COX-1, COX-2 and 5-LOX mRNA.


RESULTS
Expression of COX-1, COX-2, and 5-LOX mRNA was found in all samples - in the muscle cells, inflammatory cells and in vessels. COX-1 mRNA expression predominated in the inflammatory cells and vessels and was higher in affected than in non-affected sites detected by MRI (mean intensity 3.22+/-0.67 vs. 2.0+/-0.87; p = 0.0006). The expression of COX-2 mRNA was high mainly in inflammatory cells and/or vessels and was increased in MRI-detected affected tissues (3.5+/-0.88; 1.9+/-1.1; p = 0.003), as was the expression of COX-2 mRNA in muscle cells (2.1+/-1.0 vs. 1.3+/-1.0; p = 0.021). 5-LOX mRNA was largely expressed in muscle cells from MRI-detected affected sites and the signal intensity was higher in comparison with samples taken from non-affected tissues detected by MRI (3.22+/-0.7 vs. 1.67+/-0.7; p = 0.0007).


CONCLUSIONS
Expression of COX-1, COX-2 and 5-LOX mRNA was observed for the first time in muscle tissues from IIM patients. This expression was increased in affected tissues detected by MRI, which may suggest a role of COX-1, COX-2, and 5-LOX in the pathogenesis of IIM.
Institute of Rheumatology, Prague, Czech Republic.
J T
JT
Studýnková
S
S
Kuchen
E
E
Jeisy
J
J
Schedel
F
F
Charvát
K
K
Jarosová
H
H
Sprott
M
M
Matucci-Cerinic
R E
RE
Gay
B A
BA
Michel
K
K
Pavelka
J
J
Vencovský
S
S
Gay
D000328:Adult; D001094:Arachidonate 5-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D003882:Dermatomyositis / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology; D017285:Polymyositis / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D001094:Arachidonate 5-Lipoxygenase; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases