難治性胃潰瘍の病理形態学的特徴―新しい視点からみた胃潰瘍の治癒過程と難治化

Morphopathologic Features of Refractory Gastric Ulcer: New Concepts of the Healing Process and Intractability of Gastric Ulcer

要旨　胃潰瘍の治癒に働く組織因子は再生上皮と間葉組織である．この治癒には，間葉組織による潰瘍の収縮，潰瘍底の挙上・浅化，再生上皮による潰瘍表面の被覆，および間葉組織と再生上皮の順調な経時的変化が重要である．今日まで，再生上皮の研究に比べ，間葉組織のそれは極めて貧弱であった．筆者らは，初めて，間葉組織の経時的変化を明らかにした．そして，内側線維症と外側線維症が存在し，それらが潰瘍収縮，潰瘍底の挙上・浅化に重要であることを明確にした．内側線維症は筋線維芽細胞や線維芽細胞から形成され，膠原・筋線維症となり，最終的に平滑筋束のみとなり，筋層融合像や厚い粘膜筋板の形態をとって，永続して残存することも明らかにした．一方，外側線維症は膠原線維症となり，後に消失することも明らかにした．これら新知見を基にして，難治性胃潰瘍の形態学的特徴を述べた．

　Histological factors that affect the healing of gastric ulcers are regenerative epithelium and mesenchymal tissue. This healing process consists of the following important factors: reduction in ulcer size, and elevation and shallowing of an ulcer base by mesenchymal tissue, as well as covering of the ulcer by regenerative epithelium, and favorable histologic change in mesenchymal tissue and regenerative epithelium with time. Research on mesenchymal tissue is not as advanced as that on regenerative epithelium. We were the first researchers to demonstrate sequential changes in mesenchymal tissue in ulcer healing. There are inner and outer fibrosis which have an important role in reduction of ulcer size, and elevation and shallowing of the ulcer base. An inner fibrosis consisting of myofibroblasts and fibroblasts develops into collagenomusculosis and at last into musculosis, forms a muscle layer fusion and thick muscularis mucosa, and stay in the tissue chronically. On the other hand, outer fibrosis tends to be collagen bands (collagenosis) which disappear later. We discuss the morphological characteristics of refractory gastric ulcers based on our new findings.