Kashibuchi Nobuo, Hirai Yoshikazu, O'Goshi Kenichiro, Tagami Hachiro
Pola Laboratories, Pola Chemical, Inc. 27-1, Takashimadai, Kanagawa-ku, Yokohama 221-0833, Japan.
Skin Res Technol. 2002 Nov;8(4):203-11. doi: 10.1034/j.1600-0846.2002.00348.x.
BACKGROUND/AIMS: The past morphological studies on individual corneocytes have so far mainly focused on their two-dimensional characteristics, particularly on their projected area, which have been widely employed for the estimation of the turnover rate of the stratum corneum because of the practical use. However, sometimes a poor correlation has been reported between the projected area of corneocytes and actually measured turnover time of the stratum corneum. The objective of the present study is to perform detailed three-dimensional measurements of individual corneocytes with atomic force microscope. Through analyses of the obtained data, we tried to find morphological parameters that reflect more closely the differentiation process of the corneocytes in the stratum corneum than the frequently used two-dimensional projected area.
We measured such morphological parameters as the volume, average thickness and real surface area of individual corneocytes isolated from the covered skin (the flexor surface of the upper arm) and the exposed skin (the cheek) of 12 healthy individuals belonging to different age brackets, in addition to their projected area. We further introduced a new parameter, a flatness index calculated by dividing the projected area of corneocytes by their thickness. Similarly, we measured corneocytes obtained from eight patients with atopic dermatitis (AD) and psoriatic patients.
Obtained results showed that most of these morphological parameters varied greatly depending upon the anatomical location and age of the subjects. Needless to say great differences were found between healthy skin and lesional skin of atopic dermatitis or psoriasis. However, the volume and thickness of corneocytes collected from the same location of normal skin of the covered area (upper arm) with tape-strippings were noted to decrease as they differentiated in the stratum corneum, showing an increase in their surface area and projected area with a resultant increase in the flatness index. Moreover, the corneocyte collected from the lesional skin of AD or psoriasis showed a great decrease in flatness index, reflecting their poor differentiation in the stratum corneum due to its enhanced turnover rate. Most of all, we found a poor correlation between the projected area and the various three-dimensional morphologic parameters of the corneocytes, indicating that the projected area does not reflect the volume or thickness of corneocytes that are also greatly influenced by the differentiation process of corneocytes in the stratum corneum.
To estimate the differentiation speed of the corneocytes, we suggest using their flatness index rather than the two-dimensional cell surface area, because the former is a concept that takes into account the three-dimensional characteristics of corneocytes.
背景/目的：过去对单个角质形成细胞的形态学研究主要集中在其二维特征上，尤其是其投影面积，由于其实用性，该投影面积已被广泛用于估计角质层的更新率。然而，有时据报道角质形成细胞的投影面积与实际测量的角质层更新时间之间的相关性较差。本研究的目的是使用原子力显微镜对单个角质形成细胞进行详细的三维测量。通过对所得数据的分析，我们试图找到比常用的二维投影面积更能紧密反映角质层中角质形成细胞分化过程的形态学参数。
我们测量了从12名不同年龄段健康个体的覆盖皮肤（上臂屈侧）和暴露皮肤（脸颊）中分离出的单个角质形成细胞的形态学参数，如体积、平均厚度和真实表面积，以及它们的投影面积。我们还引入了一个新参数，即通过将角质形成细胞的投影面积除以其厚度计算得出的平整度指数。同样，我们测量了从8名特应性皮炎（AD）患者和银屑病患者中获得的角质形成细胞。
所得结果表明，这些形态学参数中的大多数因受试者的解剖位置和年龄而异。不用说，特应性皮炎或银屑病的健康皮肤与病变皮肤之间存在很大差异。然而，用胶带剥离法从覆盖区域（上臂）正常皮肤的同一位置收集的角质形成细胞的体积和厚度在角质层中分化时会降低，其表面积和投影面积增加，平整度指数随之增加。此外，从AD或银屑病病变皮肤中收集的角质形成细胞的平整度指数大幅下降，这反映了由于其更新率提高，它们在角质层中的分化较差。最重要的是，我们发现角质形成细胞的投影面积与各种三维形态学参数之间的相关性较差，这表明投影面积不能反映角质形成细胞的体积或厚度，而角质形成细胞的体积或厚度也受到角质层中角质形成细胞分化过程的很大影响。
为了估计角质形成细胞的分化速度，我们建议使用其平整度指数而非二维细胞表面积，因为前者是一个考虑了角质形成细胞三维特征的概念。
