Desquamation enzymes involved

Lundstrom and Egelrud10 found a unipolar spontaneous cell dissociation in pieces of hypertrophic human plantar stratum corneum incubated in a simple buffer. The cell dissociation occurred only at the surface that had faced outward in vivo. The rate of cell dissociation was increased in the presence of EDTA. It was inhibited by inhibitors of serine proteases, but not by inhibitors of other groups of proteases. Since the tissue had not been heated with exogenous proteases before the experiments, it was concluded that the observed cell dissociation was mediated by an endogenous serine protease. This experimental system has been used as an in vitro model of desquamation. In addition to information about the enzyme(s) involved in the cell dissociation, it has provided information about the nature of the cohesive structures in the stratum corneum. 

The composition of the stratum corneum intercellular lipids may have profound effects on desquamation. In addition to modifying effects on, for example, proteolytic enzymes and their substrates,34 lipids may also be directly involved in corneocyte cohesion. The effects of cholesterol sulfate have already been mentioned. In addition to RXI, there are a number of other hereditary diseases with disorders of desquamation associated with disturbances in lipid metabolism. Furthermore, scaling as a result of treatment with lipid-lowering drugs has been observed (for review, see References 1 and 2). 

Lundstrom, A. and Egelrud, T., Stratum corneum chymotryptic enzyme a proteinase which may be generally present in the stratum corneum and with a possible involvement in desquamation, Acta Derm. Venereol. (Stockh.), 71, 471, 1991. 

Egelrud, T., Purification and preliminary characterization of stratum corneum chymotryptic enzyme a proteinase that may be involved in desquamation, J. Invest. Dermatol., 101,200, 1993. 

Ekholm, E. and Egelrud, T., The expression of stratum corneum chymotryptic enzyme in human anagen hair follicles further evidence for its involvement in desquamation-like processes, Br. J. Dermatol., 139, 585, 1998. 

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