Aging-associated barrier dysfunction.

<p>Upon gross observation, obvious signs of dermatitis were evident in aging Inv-Cldn6-CΔ196 transgenic mice, especially in areas subjected to repetitive mechanical stress such as the neck and behind the ears (<b>A</b>). Histological evaluation revealed a significantly thickened epidermis with an increased number of spinous/suprabasal cell layers and cellular disorganization; the upper differentiation layers were also abnormal, with parakeratosis, the prevalent appearance of nuclei, an improperly packed granular layer and a thicker stratum corneum (<b>B</b>). TEWL measurements across the dermatitis-affected transgenic skin confirmed an approximately 8-fold increase in water loss and a barrier deficient phenotype (<b>C</b>).