Different expression pattern of serum soluble intercellular adhesion molecules-1 and neutrophilic expression of CD18 in patients with diabetic retinopathy

AIM

To investigate the levels of serum soluble intercellular adhesion molecules-1(sICAM-1) and neutrophilic expression of CD18 in patients with various stages of diabetic retinopathy and to determine their different expression pattern in the development of diabetic retinopathy(DR).

METHODS

Levels of serum sICAM-1 and CD18 on the surface of neutrophile were measured in 41 DR patients, they were classified in three subgroups according to the stage of retinopathy as determined by fund''s ophthalmoscopy; 10 control subjects were also studied. sICAM-1 were measured by enzyme-linked immunosorbent assay and CD18 by flow cytometry.

RESULTS

The neutrophilic CD18 expression and serum sICAM-1 level were all significantly elevated in all diabetic subgroups compared to control subjects (P<0.01). The differences of CD18 and sICAM-1 among the diabetic subgroups were significant in CD18 but not in sICAM-1. The progression of retinopathy was associated with an increase both in CD18 and in sICAM-1 levels by simple correlation analysis (β=0.74, P<0.001; β=0.38, P<0.01, respectively). But stepwise multiple regression analysis revealed that only CD18 was independent determinant of retinopathy (β=1.04, P<0.01).

CONCLUSION

Our results confirm the contribution of endothelial and neutrophilic activation in the development of DR as indicated by increased levels of CD18 and sICAM-1. However, a direct implication of CD18 and ICAM-1 in the progression of DR can be supported only in the CD18 but not ICAM-1. CD18 and ICAM-1 may play different role in the development of diabetic retinopathy.