Cultured nail keratinocytes express hard keratins characteristic of nail and hair in vivo

In the 1992 study by Kitahara and Ogawa, researchers cultured cells from the human ventral nail matrix and confirmed the expression of hard keratins, which are found in both nail and hair but not in the epidermis, using indirect immunofluorescence. The presence of hard keratins in these cells suggested that they could serve as a marker for cultured nail cells and that these cells express differentiation-related keratins at a calcium concentration of 0.15 mM, which may indicate they are in the differentiation stage. This research provided a model for studying the differentiation of nail and potentially hair cells in vitro, although the study did not specify the number of participants as it used cells from a single healthy adult man.