Nguyen Long, Dohi Teruyuki, Watanabe-Takano Haruko, Fukuhara Shigetomo, Ogawa Rei
Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan.
Department of Molecular Pathophysiology, Institute of Advanced Medical Sciences, Nippon Medical School, Tokyo, Japan.
Wound Repair Regen. 2025 Mar-Apr;33(2):e70015. doi: 10.1111/wrr.70015.
Keloids are a complex type of scar tissue formed by exaggerated wound healing, characterised by the overgrowth of thick fibrous tissue beyond the original wound boundary. While the crucial relationship between keloid formation and the vascular system has been highlighted, conflicting findings have been reported regarding the characterisation of keloid vasculature. Here, we successfully characterised the detailed three-dimensional (3D) structure of vasculature in keloid tissues using tissue clearing methods combined with 3D imaging. First, we compared two optical tissue clearing methods, the clear, unobstructed brain imaging cocktails and computational analysis and immunolabelling-enabled 3D imaging of solvent-cleared organ protocols, and found the latter to provide greater transparency of keloid scars. We then conducted a detailed 3D vascular analysis using light sheet and confocal fluorescence microscopy. In normal skin, capillary loops and the superficial vascular plexus were located in the papillary layer and at the boundary between the papillary and reticular layers, respectively. However, the density of these vessels was higher in keloid scars than in normal skin. The reticular layer of normal skin exhibited fewer blood vessels. In contrast, keloid scars exhibited significantly thickened dermal reticular layers, with the upper reticular layer showing significantly greater vascularisation. The lower reticular layer of keloid scars also exhibited vertically aligned blood vessels, although their density was lower than in the upper reticular layer. These results indicate that excessive vascularisation is predominantly induced in the papillary and upper reticular layers of keloid scars, which might contribute to keloid pathogenesis. The technique described here has the potential to serve as a crucial template for future pathological analyses of abnormal scars.
瘢痕疙瘩是一种由伤口愈合过度形成的复杂瘢痕组织类型，其特征是厚纤维组织过度生长超出原始伤口边界。虽然瘢痕疙瘩形成与血管系统之间的关键关系已得到强调，但关于瘢痕疙瘩血管系统特征的报道却相互矛盾。在此，我们使用组织透明化方法结合三维成像成功地描绘了瘢痕疙瘩组织中血管系统的详细三维结构。首先，我们比较了两种光学组织透明化方法，即透明无阻脑成像鸡尾酒法和溶剂清除器官方案的计算分析及免疫标记三维成像法，发现后者能使瘢痕疙瘩瘢痕具有更高的透明度。然后，我们使用光片和共聚焦荧光显微镜进行了详细的三维血管分析。在正常皮肤中，毛细血管袢和浅表血管丛分别位于乳头层以及乳头层和网状层之间的边界处。然而，这些血管的密度在瘢痕疙瘩瘢痕中比在正常皮肤中更高。正常皮肤的网状层血管较少。相比之下，瘢痕疙瘩瘢痕的真皮网状层明显增厚，上部网状层血管化程度明显更高。瘢痕疙瘩瘢痕的下部网状层也有垂直排列的血管，尽管其密度低于上部网状层。这些结果表明，瘢痕疙瘩瘢痕的乳头层和上部网状层主要发生了过度血管化，这可能与瘢痕疙瘩的发病机制有关。这里描述的技术有可能成为未来异常瘢痕病理分析的关键模板。
