Skin distribution and differential expression of transforming growth factor beta 1 and beta 2.

Transforming growth factor beta (TGF-beta) 1 and 2 have both become increasingly important in cutaneous biology, but their expression and distribution in human skin are not entirely clear. In this report, normal forearm skin from four volunteers was investigated for TGF-beta 1 and beta 2 immunostaining with antibodies that detect preferentially either cell- or matrix-associated forms of these peptides. Marked cell-associated TGF-beta 1 was found in the dermis, particularly around blood vessels and ducts; cellular TGF-beta 2 immunostaining was less prominent, and was predominantly around blood vessels. Neither TGF-beta 1 nor -beta 2 could be detected in the epidermis or epithelial structures, and the dermal matrix contained minimally detectable amounts of the two isoforms. In all cases, dermal matrix and cells contained greater amounts of TGF-beta 1 than TGF-beta 2. Previous studies have shown that both TGF-beta 1 and -beta 2 can induce dramatic increases in extracellular matrix, and both peptides have been implicated in the pathogenesis of fibrosis. We therefore investigated TGF-beta 1 and -beta 2 immunostaining in involved forearm skin of four patients with systemic sclerosis. Compared to normal skin, fibrotic specimens showed increased amounts of matrix and epidermal TGF-beta 1, but not TGF-beta 2. We conclude that TGF-beta 1 and -beta 2 expression in human skin is differentially regulated, and that their distribution is varied and complex.