Increased expression of gelatinases A and B by skin explants from patients with anetoderma.

The extent of alterations to the elastic fibre network in lesional skin areas of three patients with anetoderma was assessed by quantitative image analysis of tissue sections and compared with morphometric parameters from unaffected sites of the same individuals. In the anetodermic skins pre-elastic fibres were undetectable or extremely rare: the volume fraction (Vv%) occupied by these pre-elastic fibres was 0-0.3%, while in unaffected skins the Vv% occupied by pre-elastic fibres was 0.5-0.8%. A nearly complete absence of dermal elastic fibres in lesional skins from the three patients was evidenced (Vv% = 0.2-0.3%). Organ cultures were performed using explants from skin with or without anetodermic lesions to quantify the expressions of elastase-type proteinases. All tissues from anetodermic lesions expressed proforms of gelatinases A and B and the activated form of gelatinase A; their levels increased with the culture time. In comparison, enzymatic activities on oligopeptide substrates specific for leucocyte elastase and fibroblast plasma membrane-associated metalloelastase were not detected in the conditioned media of any explants at any time of culture from 1 to 5 days. Increased production of progelatinases A and B and activation of progelatinase A could be mainly responsible for the degradation of skin elastic fibres demonstrated in anetodermic skins.