We studied the mechanisms of diabetic macular edema, focusing on results of our recent studies. Diabetic macular edema is one form of tissue edema, which can occur systemically. The cause of tissue edema can be an increase in vascular permeability, an increase in intravascular pressure, a decrease in intravascular osmotic pressure, or disturbance of extracellular fluid outflow. Because the retina has less extracellular matrix, which can be a buffer against edema, than other tissues, retinal function is impaired by minimal degrees of tissue edema. The retina has a strong barrier to vascular permeability, the blood-retinal barrier, and impairment of this barrier is the most important cause of retinal edema. Accumulating evidence indicates that vascular endothelial growth factor (VEGF) is the cytokine that is most important in increasing retinal vascular permeability in those with diabetes, and we have found that tissue factor (TF) also seems to have an important role in diabetic retinopathy. One of our studies showed that TF is up-regulated by VEGF in cultured retinal vascular endothelial cells. In another study, the amount of TF in the aqueous humor of patients with diabetic retinopathy was higher in those with more severe diabetic retinopathy. An immunohistochemical study of diabetic eyes found that TF was mostly located in the retinal vascular wall. These results indicate that TF can play a role in the progression of diabetic retinopathy. Furthermore, surgical specimens of cortical vitreous obtained at vitrectomy have been found to contain a variety of cells, including hyalocytes. The findings that hyalocytes are present in the vicinity of the neural retina and can produce pro-inflammatory cytokines in vitro suggest that hyalocytes can play a causal role in the progression of diabetic macular edema. Better understanding of these processes would lead to the development of better treatment for diabetic macular edema.
|Number of pages||5|
|Journal||Folia Ophthalmologica Japonica|
|Publication status||Published - 2004|
All Science Journal Classification (ASJC) codes