Source: Auris Nasus Larynx  |  Posted 9 years ago

Patients with proliferative diabetic retinopathy show reduced intraocular production of insulin-like growth factor 1 (IGF-1), which seems to play a role in retinal homoeostasis.

Researchers from the Hospital General Vall d'Hebron, Barcelona, Spain, enrolled 36 patients with diabetes and proliferative diabetic retinopathy, and 28 patients without diabetes, who all underwent vitrectomy. The subjects were matched for age, sex and serum levels of free IGF-1.

The patients with diabetes and proliferative diabetic retinopathy showed raised levels of free IGF-1 in the vitreous fluid compared to those patients without diabetes. However, free IGF-1 levels were lower in the proliferative diabetic retinopathy group after adjusting for levels of proteins in the vitreous. Differences in the distribution of IGF binding proteins 1 and 3 in the vitreous did not explain the relatively lower levels of free IGF-1.

The contribution of free to total IGF-1 in vitreous fluid was 10% in those with proliferative diabetic retinopathy. This compared to 42% in those without diabetes. In comparison, the contribution in the serum as less than 1%.

The authors concluded that the increased intravitreous levels of free IGF-1 in patients with proliferative diabetic retinopathy reflect diffusion from serum. They suggested that patients with proliferative diabetic retinopathy show a deficit in intraocular production of free IGF-1. Finally, they argued that the findings suggest that IGF-1 produced by the eye plays a role in retinal homoeostasis.