Nuutila Kristo, Singh Mansher, Kruse Carla, Eriksson Elof
Boston, Mass.; and Odense, Denmark.
From the Division of Plastic Surgery, Department of Surgery, Brigham & Women's Hospital, Harvard Medical School; and the Department of Plastic and Reconstructive Surgery, Odense University Hospital.
Plast Reconstr Surg. 2017 Aug;140(2):306-314. doi: 10.1097/PRS.0000000000003516.
Epidermal stem cells present in the skin appendages of the dermis might be crucial in wound healing. In this study, the authors located these cells in the dermis and evaluated their contribution to full-thickness wound healing in a porcine model.
Four sequentially deeper 0.35-mm-thick skin grafts were harvested from the same donor site going down to 1.4 mm in depth (layers 1 through 4). The layers were minced to 0.8 × 0.8 × 0.35-mm micrografts and transplanted (1:2) onto full-thickness porcine wounds. Healing was monitored up to 28 days and biopsy specimens were collected on days 6 and 10. Multiple wound healing parameters were used to assess the quality of healing.
The authors' results showed that wounds transplanted with layer 2 (0.35 to 0.7 mm) and layer 3 (0.7 to 1.05 mm) micrografts demonstrated reepithelialization rates comparable to that of split-thickness skin graft (layer 1, 0.00 to 0.35 mm; split-thickness skin graft) at day 10. At day 28, dermal micrografts (layers 2 and 3) showed quality of healing comparable to that of split-thickness skin grafts (layer 1) in terms of wound contraction and scar elevation index. The amounts of epidermal stem cells [cluster of differentiation (CD) 34] and basal keratinocytes (KRT14) at each layer were quantified by immunohistochemistry.
The analysis showed that layers 2 and 3 contained the most CD34 cells and layer 1 was the richest in KRT14 cells. The immunohistochemistry also indicated that, by day 6, CD34 cells had differentiated into KRT14 cells, which migrated from the grafts and contributed to the reepithelialization of the wound.
真皮皮肤附属器中存在的表皮干细胞可能在伤口愈合中起关键作用。在本研究中，作者在真皮中定位了这些细胞，并在猪模型中评估了它们对全层伤口愈合的贡献。
从同一供体部位依次切取四层厚度为0.35毫米的皮肤移植物，深度达1.4毫米（第1至4层）。将这些层切成0.8×0.8×0.35毫米的微小移植物，并以1:2的比例移植到猪的全层伤口上。监测愈合情况直至28天，并在第6天和第10天收集活检标本。使用多个伤口愈合参数来评估愈合质量。
作者的结果表明，移植第2层（0.35至0.7毫米）和第3层（0.7至1.05毫米）微小移植物的伤口在第10天时的再上皮化率与断层皮片（第1层，0.00至0.35毫米；断层皮片）相当。在第28天时，真皮微小移植物（第2层和第3层）在伤口收缩和瘢痕隆起指数方面显示出与断层皮片（第1层）相当的愈合质量。通过免疫组织化学对每层的表皮干细胞[分化簇（CD）34]和基底角质形成细胞（KRT14）的数量进行了定量。
分析表明，第2层和第3层含有最多的CD34细胞，第1层富含KRT14细胞。免疫组织化学还表明，到第6天时，CD34细胞已分化为KRT14细胞，这些细胞从移植物迁移并促进了伤口的再上皮化。
