Immunohistochemical studies of vascular endothelial growth factor in skin of patients with amyotrophic lateral sclerosis

Vascular endothelial growth factor (VEGF) is a disulfide-linked dimeric glycoprotein that enhances vascular permeability, induces chemotaxis and activation of monocytes/macrophages, and promotes growth of vascular endothelial cells. Furthermore, VEGF is a multifunctional cytokine, which influences neural cells directly, enhancing neuronal survival, axonal outgrowth, and Schwann cell proliferation. So far studies of the skin of amyotrophic lateral sclerosis (ALS) have shown unique pathological and biochemical abnormalities in collagen, elastic fibers, and the ground substance. However, the expression of VEGF in ALS skin has not previously been studied. We made a quantitative immunohistochemical study of the expression of VEGF in the skin from 15 patients with ALS and 15 control subjects. VEGF immunoreactivity was markedly positive in the epidermis and moderately positive in some dermal blood vessels and glands in ALS patients. These findings became more conspicuous as ALS progressed. The optical densities for VEGF immunoreactivity of the epidermis in ALS patients were significantly higher (p < 0.001) than in control subjects. In addition, there was an appreciable positive correlation (r = 0.85, p < 0.001) in ALS patients between the densities for VEGF immunoreactivity and duration of illness, but there was no such correlation in control subjects. These data suggest that changes of VEGF in ALS skin are likely to be related to the disease process and that metabolic alterations of VEGF may take place in the skin of patients with ALS.