Increased amyloid beta protein in the skin of patients with amyotrophic lateral sclerosis.

Distinct vascular and periadnexal immunoreactivity have been observed for amyloid b protein (Abeta) in skin from patients with amyotrophic lateral sclerosis (ALS). We used an enzyme-linked immunosorbent assay to make a more quantitative comparison of Abeta concentrations between ALS patients and controls. The insoluble fractions of skin samples from ALS patients contained significantly higher Abeta concentrations per milligram protein than those from controls. Various alterations in extracellular matrix components have been reported to occur in the skin of patients with ALS, and several matrix constituents have been shown to affect processing and aggregation of Abeta in human brain. Taking these previous findings together with those of the present study, our observations suggest that changes in extracellular matrix in skin of ALS patients may facilitate aggregation and deposition of Abeta.