Increased osteopontin levels in the vitreous of patients with diabetic retinopathy.
OBJECTIVE
Osteopontin (OPN) has diverse functions such as cell adhesion, chemoattraction, immunomodulation, and angiogenesis. The aim of this study is to analyze the OPN levels in vitreous fluid obtained from diabetic retinopathy (DR) and non-DR patients.


METHODS
Nineteen patients out of 11 with DR and 8 without DR underwent pars plana vitrectomy and vitreous fluid was obtained simultaneously. Two distinct sandwich enzyme-linked immunosorbent assay systems (systems 1 and 2) were applied, which have been developed in our laboratories to quantify the OPN concentrations in vitreous fluid.


RESULTS
The non-thrombin-cleaved full-length OPN levels in the vitreous fluid were 921.63 +/- 45.38 ng/ml in DR and 632.80 +/- 83.43 ng/ml in non-DR using system 1. Also, vitreous thrombin-cleaved and noncleaved OPN levels were increased to 2,109.22 +/- 151.651 and 1,651.13 +/- 229.82 ng/ml in patients with DR and non-DR using system 2. The vitreous OPN levels were significantly higher in DR than those in non-DR (p < 0.01 by system 1 and p < 0.05 by system 2).


CONCLUSIONS
Thrombin-cleaved and noncleaved vitreous OPN levels in patients with DR were increased compared with control subjects, suggesting that OPN plays a potential role in the pathogenesis of diabetic retinal ischemia.
Kase
Satoru
S
Department of Ophthalmology and Visual Sciences, Hokkaido University Graduate School of Medicine, Sapporo, Japan. kaseron@med.hokudai.ac.jp
Yokoi
Masahiko
M
Saito
Wataru
W
Furudate
Naoki
N
Ohgami
Kazuhiro
K
Kitamura
Mizuki
M
Kitaichi
Nobuyoshi
N
Yoshida
Kazuhiko
K
Kase
Manabu
M
Ohno
Shigeaki
S
Uede
Toshimitsu
T
D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000601:surgery; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053495:Osteopontin / Q000378:metabolism*; D012720:Severity of Illness Index; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
D015415:Biomarkers; D053495:Osteopontin