Tissue factor increases in the aqueous humor of proliferative diabetic retinopathy.
BACKGROUND
Tissue factor (TF) is a cellular initiator of the coagulation cascade and is upregulated by the major factors of diabetic angiopathy, TF might thus be one of the key molecules in diabetic retinopathy (DR).


OBJECTIVE
To measure TF in diabetic eyes and evaluate its possible role in DR.


METHODS
TF concentration in the aqueous humor of the eyes in 44 patients with diabetes and 35 age-matched control patients was evaluated by ELISA. The concentration of TF in aqueous humor (AH) was compared with the grade of DR. The concentration of TF in AH was also compared with duration of diabetes, renal function, and blood glucose control. The serum TF concentration in each group was also compared. The correlation between the serum TF and aqueous TF in each patient was analyzed. The effect of vascular endothelial growth factor (VEGF) on the TF activity of cultured bovine retinal endothelial cells was evaluated.


RESULTS
The mean TF concentration in AH was higher in patients with active proliferative DR (244.5 pg/ml) than in either those with non-proliferative DR (132.4 pg/ml, P<0.05) or the control patients (114.9 pg/ml, P<0.01). The serum TF concentration in active proliferative DR patients (348.3 pg/ml) was significantly higher than in either non-proliferative DR patients, (235.9 pg/ml, P<0.01) or in the controls (223.5 pg/ml, P<0.01). However, the TF concentration of AH was not significantly correlated to that of the serum in each patient. The TF concentration in AH closely correlated with the grade of DR and protein concentration. VEGF increased the biological activity of TF in vitro.


CONCLUSIONS
The origin of TF in AH, however, is still not clearly understood. Nonetheless, TF in AH directly reflects the severity of ocular diabetic change, and the present results indicate that TF indeed plays some role in the progression of DR.
Sakamoto
T
T
Department of Ophthalmology and Pathology, Faculty of Medicine, Kyushu Graduate School of Medicine, Fukuoka, Japan. tsakamot@med.kyushu-u.ac.jp
Ito
S
S
Yoshikawa
H
H
Hata
Y
Y
Ishibashi
T
T
Sueishi
K
K
Inomata
H
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000378:metabolism*; D002478:Cells, Cultured; D003930:Diabetic Retinopathy / Q000145:classification / Q000378:metabolism* / Q000503:physiopathology; D018450:Disease Progression; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000187:drug effects / Q000378:metabolism; D013925:Thromboplastin / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D013925:Thromboplastin