Department of Dermatology, Venerology and Allergology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
Dermatology. 2023;239(3):478-493. doi: 10.1159/000529577. Epub 2023 Feb 14.
The knowledge about the location and kinetics of tattoo pigments in human skin after application and during the recovery is restricted due to the limitation of in vivo methods for visualizing pigments. Here, the localization and distribution of tattoo ink pigments in freshly and old tattooed human skin during the regeneration of the epidermis and dermis were investigated in vivo.
Two-photon excited fluorescence lifetime imaging (TPE-FLIM) was used to identify tattoo ink pigments in human skin in vivo down to the reticular dermis. One subject with a freshly applied tattoo and 10 subjects with tattoos applied over 3 years ago were investigated in the epidermal and dermal layers in vivo. One histological slide of tattooed skin was used to localize skin-resident tattoo pigment using light microscopy.
The carbon black particles deposited around the incision have still been visible 84 days after tattoo application, showing delayed recovery of the epidermis. The TPE-FLIM parameters of carbon black tattoo ink pigments were found to be different to all skin components except for melanin. Distinction from melanin in the skin was based on higher fluorescence intensity and agglomerate size. Using TPE-FLIM in vivo tattoo pigment was found in 75% of tattoos applied up to 9 years ago in the epidermis within keratinocytes, dendritic cells, and basal cells and in the dermis within the macrophages, mast cells, and fibroblasts. Loading of highly fluorescent carbon black particles enables in vivo imaging of dendritic cells in the epidermis and fibroblasts in the dermis, which cannot be visualized in native conditions. The collagen I structures showed a higher directionality similar to scar tissue resulting in a greater firmness and decreased elasticity of the tattooed skin.
Here, we show the kinetics and location of carbon black tattoo ink pigment immediately after application for the first time in vivo in human skin. Carbon black particles are located exclusively intracellularly in the skin of fresh and old tattoos. They are found within macrophages, mast cells, and fibroblasts in the dermis and within keratinocytes, dendritic cells, and basal cells in the continuously renewed epidermis even in 9-year-old tattoos in skin showing no inflammation.
由于体内方法在可视化颜料方面的局限性，人们对纹身颜料在人体皮肤中的位置和动力学的了解受到限制。本研究旨在体内研究表皮和真皮再生过程中，新鲜和陈旧纹身皮肤中纹身墨颜料的定位和分布。
双光子激发荧光寿命成像（TPE-FLIM）用于识别人体皮肤中的纹身墨颜料，可深入至网状真皮层。对一名新纹身的受试者和 10 名纹身 3 年以上的受试者进行了体内表皮和真皮层的研究。使用一张纹身皮肤的组织学切片，通过明场显微镜定位皮肤内的纹身颜料。
纹身 84 天后，切口周围的碳黑颗粒仍可见，表明表皮恢复缓慢。碳黑纹身墨颜料的 TPE-FLIM 参数与除黑色素以外的所有皮肤成分均不同。与皮肤中的黑色素区分开来的依据是更高的荧光强度和团聚体大小。在体内使用 TPE-FLIM，可在 9 年前应用的纹身中，于表皮的角质形成细胞、树突状细胞和基底细胞，以及真皮的巨噬细胞、肥大细胞和成纤维细胞中发现纹身颜料。高荧光碳黑颗粒的加载可实现体内对表皮树突状细胞和真皮成纤维细胞的成像，而在自然条件下这些细胞无法成像。I 型胶原蛋白结构显示出更高的方向性，类似于瘢痕组织，导致纹身皮肤的硬度增加和弹性降低。
本研究首次在体内观察到纹身墨颜料在人体皮肤中的动力学和位置。碳黑颗粒仅位于新鲜和陈旧纹身皮肤的细胞内。它们存在于真皮中的巨噬细胞、肥大细胞和成纤维细胞中，以及不断更新的表皮中的角质形成细胞、树突状细胞和基底细胞中，即使在没有炎症的 9 年陈旧纹身中也能发现。
