Age-related NADPH Oxidase (arNOX) Activity Correlated with Cartilage Degradation and Bony Changes in Age-related Osteoarthritis.
The purpose of this study was to investigate the age-related NADPH oxidase (arNOX) activity in patients with age-related knee osteoarthritis (OA). Serum and cartilage arNOX activities were determined using an oxidized ferricytochrome C reduction assay. Full-thickness knee joint cartilages obtained through total knee replacement surgery were graded according to the Outerbridge (OB) classification. Radiographic severity of OA was determined on Knee X-rays according to the Kellgren-Lawrence (K/L) grading system. Cartilage β-galactosidase, HIF-1α, and GLUT-1 expression levels were evaluated as markers for tissue senescence, hypoxia, and glycolysis. Higher arNOX activities occurred with higher levels of cartilage β-galactosidase, HIF-1α, and GLUT-1 (P = 0.002). arNOX activity in cartilages with surface defects (OB grade II, III) was higher than in those without the defects (OB grade 0, I) (P = 0.012). Cartilage arNOX activity showed a positive correlation with serum arNOX activity (r = -0.577, P = 0.023). Serum arNOX activity was significantly higher in the OA subgroup with bilateral ROA than in the OA with no or unilateral ROA (2.449 ± 0.81, 2.022 ± 0.251 nM/mL, respectively, P = 0.019). The results of this study demonstrate that OA itself is not a cause to increase arNOX activities, however, arNOX hyperactivity is related to a high degree of cartilage degradation, and a high grade and extent of ROA in age-related OA.
Department of Internal Medicine, College of Medicine, Yeungnam University, Daegu, Korea.
Min-Jung
MJ
Kim
Department of Internal Medicine, College of Medicine, Yeungnam University, Daegu, Korea.
Hyun-Je
HJ
Kim
Department of Internal Medicine, College of Medicine, Yeungnam University, Daegu, Korea.
Young-Hoon
YH
Hong
Department of Internal Medicine, College of Medicine, Yeungnam University, Daegu, Korea.
Choong-Ki
CK
Lee
Department of Physiology, College of Medicine, Yeungnam University, Daegu, Korea.
Yong-Woon
YW
Kim
Department of Orthopedic Surgery, College of Medicine, Yeungnam University, Daegu, Korea.
Oog-Jin
OJ
Shon
Department of Anatomy, College of Medicine, Yeungnam University, Daegu, Korea.
In-Hwan
IH
Song
D015415:Biomarkers / Q000378:metabolism; D002357:Cartilage Diseases / Q000201:enzymology*; D002358:Cartilage, Articular / Q000201:enzymology*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009247:NADH, NADPH Oxidoreductases; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000201:enzymology*; D010024:Osteoporosis / Q000175:diagnosis* / Q000201:enzymology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D015415:Biomarkers; D009247:NADH, NADPH Oxidoreductases; C431909:tumor-associated NADH oxidase
Age-related NOX; Aging; Cartilage; ENOX1 Protein, Human; Osteoarthritis