Studies of cell and organ culture of psoriatic and normal epidermis in vitro.

Abstract

ABSTRACTInvolved and noninvolved epidermis from 15 psoriatic patients, and epidermis from 12 normal individuals were grown under various conditions in vitro as cell and organ cultures. In the organ cultures of normal or noninvolved psoriatic skin, epidermal cells migrated around the dermis and differentiated. In psoriatic organ cultures, progressive necrotic changes were observed in the spinous cells including gradual detachment of the spinous layer from the dermis. In spite of these necrotic changes, newly‐grown basal cells which appeared on the dermal tissue in the 9 to 12‐day psoriatic explants clearly incorporated 3H‐thymidine into nuclear DNA. By electron microscopy these cells were observed to have numerous ribosomes, a few mitochondria, tonofilament‐like structures in the cytoplasm, and no hemi‐desmosomes. Dissociated epidermal cells from the involved psoriatic skin failed to grow on plastic dishes. When these cells were plated on dishes coated with increasing amounts of collagen, the rate of cellular attachment was proportional to the thickness of the collagen coating, but they were unable to grow and form epidermal monolayers. In contrast, normal and noninvolved psoriatic epidermal cells attached to the dishes regardless of the presence of collagen and formed differentiated epidermal monolayers.