Phagocytic NADPH oxidase-dependent superoxide production stimulates matrix metalloproteinase-9: implications for human atherosclerosis.
OBJECTIVE
Data suggest that matrix metalloproteinase-9 (MMP-9) has a role in atherosclerosis. The phagocytic NADPH oxidase has been also associated with atherosclerosis. This study aimed to investigate the association between phagocytic NADPH oxidase and MMP-9 in human atherosclerosis.


RESULTS
In vitro experiments performed in human monocytes showed that NADPH oxidase activation enhanced MMP-9 secretion and activity, determined by enzyme-linked immunosorbent assay and zymography, respectively. Immunohistochemical study showed that phagocytic NADPH oxidase localized with MMP-9 in endarterectomies from patients with carotid stenosis. In addition, a positive relationship (P<0.001) was found between phagocytic NADPH oxidase-dependent superoxide production determined with lucigenin and plasma MMP-9 levels in 188 asymptomatic subjects free of overt clinical atherosclerosis. In multivariate analysis, this association remained significant after adjustment for cardiovascular risk factors. Interestingly, subjects in the upper quartile of superoxide production exhibited the highest values of MMP-9, oxidized low-density lipoprotein, nitrotyrosine, carotid intima media thickness, and an increased presence of carotid plaques.


CONCLUSIONS
Enhanced NADPH oxidase-dependent *O2(-) production stimulates MMP-9 in monocytes and this relationship may be relevant in the atherosclerotic process. Moreover, MMP-9 emerges as an important mediator of the phagocytic NADPH oxidase-dependent oxidative stress in atherosclerosis.
Zalba
Guillermo
G
Division of Cardiovascular Sciences, Centre for Applied Medical Research, University Clinic, School of Medicine, University of Navarra, Pamplona, Spain. gzalba@unav.es
Fortuño
Ana
A
Orbe
Josune
J
San José
Gorka
G
Moreno
María U
MU
Belzunce
Miriam
M
Rodríguez
José Antonio
JA
Beloqui
Oscar
O
Páramo
José Antonio
JA
Díez
Javier
J
D000328:Adult; D000704:Analysis of Variance; D002340:Carotid Artery Diseases / Q000201:enzymology* / Q000503:physiopathology; D017536:Carotid Artery, Common / Q000201:enzymology* / Q000473:pathology; D016022:Case-Control Studies; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000201:enzymology; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D019255:NADPH Oxidases / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D010586:Phagocytes / Q000201:enzymology; D011336:Probability; D012680:Sensitivity and Specificity; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D019255:NADPH Oxidases; D020780:Matrix Metalloproteinase 9; D010100:Oxygen