Trophic factors and cytokines, including vascular endothelial growth factor (VEGF), insulin growth factor (IGF), mitogenic cytokine, IL-8, IL-6, and TNF-α, have been implicated in the pathogenesis of diabetic retinopathy [13], diabetic nephropathy [14], and diabetic neuropathy [15]. This evidence concerns the gene IGF1 and diabetic neuropathy.