SECNの意義

Sub-epithelial Capillary Network of the Esophageal Mucosa Observed by Magnifying Endoscopy

要旨●SECNとは食道重層扁平上皮直下に存在する細いネットワーク状の毛細血管網であり，IPCLとともに上皮を栄養している終末毛細血管である．M1，M2癌では粘膜固有層のSECNが増生し，これがbackground colorationの原因となっている．CD31などの免疫染色では粘膜固有層のmicrovessel densityは癌部で正常部分と比較し有意に増加していた．SECNの増生には粘膜固有層に浸潤した腫瘍関連マクロファージから分泌される血管新生因子が関与している．

　SECN（subepithelial capillary network）is a thin capillary network that exists just beneath the basal layer of the squamous epithelium. Both the SECN and intra-papillary capillary loop are terminal capillaries of the squamous epithelium ; they supply oxygen to the surface of the squamous epithelium. In M1 and M2 cancer, the “background coloration”, color of the background epithelium of cancerous lesions, is relatively darker compared to that of the normal squamous epithelium. The change in the background coloration is primarily attributed to an increase and thickening of the SECN beneath the cancerous epithelium because the MVD（microvessel density）of cancerous lesions is significantly higher than that of the adjacent normal squamous epithelium. The angiogenic factors released from tumor-associated macrophages that invade into the lamina propria mucosae are known to induce an increase in the SECN.