Human Advanced Microbiome Project-HMAP, Giuliani SpA, 20129 Milan, Italy.
Division of Anatomy and Physiopathology, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy.
Int J Mol Sci. 2022 Oct 8;23(19):11956. doi: 10.3390/ijms231911956.
The role of the microbiome in hair follicle (HF) growth represents a growing field of research. Here, we studied the bacterial population in the scalp hair follicles of subjects with alopecia areata (AA). Two Healthy and two AA subjects, respectively (20−60 years old), were enrolled and studied regarding the microbial community in the subepidermal scalp compartments by means of a 4-mm biopsy punch. Samples were examined by 16S sequencing, histochemical staining (Gram’s method), and transmission electron microscopy (TEM). Bacterial foci were observed in the AA subjects’ follicles with both the two adopted complementary approaches (electron microscopy and Gram staining). Significant (p < 0.05) differences were also found in the three-layer biopsy samples (p < 0.05) regarding the bacterial population. In particular, in the deep epidermis and dermis levels, a significant (p < 0.05) lower abundance of Firmicutes and a higher abundance of Proteobacteria were found in AA samples compared to the healthy control. Firmicutes also showed a significant (p < 0.05) lower abundance in hypodermis in AA subjects. In addition, Enterobacteriaceae and the genera Streptococcus, Gemella, Porphyromonas, and Granulicatella were relatively more abundant in AA groups at the deep epidermis level. The Staphylococcus and Flavobacterium genera were significantly less abundant in AA samples than in controls in all three-layer biopsy samples (p < 0.05). In contrast, Veillonella and Neisseriaceae were relatively more abundant in the healthy control group compared to the AA sample. Therefore, higher alpha diversity was observed in all three-layer biopsy samples of AA patients compared to the control. In conclusion, our data suggest that tAA could be defined as a “hair disease associated with dysregulated microbiome-immunity axis of hair follicles”.
微生物组在毛囊（HF）生长中的作用是一个不断发展的研究领域。在这里，我们研究了斑秃（AA）患者头皮毛囊中的细菌种群。分别招募了两名健康人和两名 AA 受试者（20-60 岁），通过 4mm 活检冲孔研究了表皮下头皮隔室中的微生物群落。通过 16S 测序、组织化学染色（革兰氏染色法）和透射电子显微镜（TEM）检查样本。两种方法（电子显微镜和革兰氏染色）均观察到 AA 受试者的毛囊中有细菌病灶。在三层活检样本中也发现了显著的（p < 0.05）细菌种群差异。特别是在真皮和真皮深层，与健康对照组相比，AA 样本中厚皮和浅皮的 Firmicutes 丰度显著降低（p < 0.05），而 Proteobacteria 的丰度显著升高（p < 0.05）。厚皮中 Firmicutes 的丰度也显著降低（p < 0.05）。此外，与健康对照组相比，AA 组的肠杆菌科和链球菌属、Gemella 属、卟啉单胞菌属和 Granulicatella 属在真皮深层水平上相对更丰富。葡萄球菌属和黄杆菌属在所有三层活检样本中的丰度在 AA 样本中均显著低于对照组（p < 0.05）。相反，与 AA 样本相比，韦荣球菌属和奈瑟菌科在健康对照组中相对更丰富。因此，与对照组相比，所有三层活检样本中的 AA 患者的 alpha 多样性更高。总之，我们的数据表明，tAA 可以被定义为“与毛囊微生物组-免疫轴失调相关的毛发疾病”。
