胃・十二指腸潰瘍の病態生理―主として術後の胃内外分泌細胞の消長について

Physiological and Light-electron Microscopical Studies of Parietal Cells or G Cells before and after Antrectomy and Selective Vagotomy with Pyloroplasty or Antrectomy

　従来，わが国では胃潰瘍も十二指腸潰瘍も同一の術式，すなわち広範囲胃切除術が行われてきた．この術式は1919年Finstererによって発表されたが，それまでの再発の多い小範囲胃切除術や胃空腸吻合術に代って広く世界に普及した．わが国でも宮城（1921），青山（1923）によって紹介され，大井¹⁾によって理論的に裏付けられ，潰瘍再発の少ない術式として高く評価された．しかし術後の長期追跡例が多くなるにつれて，消化吸収障害，胃切除貧血，骨軟化症などの代謝異常例や小胃症状，ダンピング症候群などの術後愁訴が問題となってきた．このため充分な減酸効果が得られ，しかも胃が大きく残る小範囲胃切除術に対する関心が高まってきた．

　Edkins（1905）²⁾，Ivy ＆ Grossman（1950）³⁾，Dragstedt（1951～4）^4)～6)，Gregory（1961）⁷⁾，Mc Guigan（1968）⁸⁾らの努力により胃液分泌の生理機構が解明されるにつれて，手術術式は大きな影響をうけた．すなわち胃液分泌は頭相，胃相，腸相によってコントロールされており³⁾，頭相の除去がDragstedt⁹⁾によって広められた迷切術であり，冑相の除去ないし減弱が各々幽門洞切除術（以下幽切術），幽門成形術（以下幽成術）である．このような頭相あるいは胃相を除去する術式は，その組み合わせにより胃が大きく残りかつ減酸効果も大きく，壁細胞領域も一部切除する広範囲胃切除術に代る術式として普及しつつある．しかし幽切術のみや迷切兼幽成術のように壁細胞領域やガストリン産生の場である幽門腺領域が完全に残った場合，術後十分な減酸が得られるだろうかという疑問が残る．

　In order to examine the relation between preserved parietal cells and gastric acid secretion, we studied the numbers of parietal cells and ultrastructural changes using materials obtained by gastroendoscopic biopsy. Gastric acid secretion were measured before and after selective operations for duodenal ulcer. As operative procedures, antrectomy, vagotomy with pyloroplasty or antrectomy were selected by acid secretory responses to medical vagotomy of Gillespie ＆ Kay (1961). After the operation, the decrease in number of parietal cells was not so great as compared with the reduction of acid secretion. However, the ultrastructural changes of parietal cells suggesting the hypofunction of the cells were observed. In addition, the response of parietal cells to histalog stimulation decreased postoperatively, according to morphological observations under electron microscope. These data suggest that the decrease in postoperative gastric acid secretion be due to the decreased sensitivity of parietal cells. On the other hand, in order to assess the function of the retained antrum following the SV＋P for duodenal ulcer patients, we measured the plasma gastrin and observed the G cells under electron microscope.

　Basal plasma gastrin increased significantly one month postoperatively (p＜0.01). Integrated gastrin response (IGR) to meat extract stimulation increased significantly six months postperatively (p＜0.01). Despite gastric vagotomy, IGR after insulin hypoglycemia stimulation increased three months postoperatively (p＜0.01). The G cells after SV＋P did not show any fine-structural features suggesting hypofunction and degeneration. On the contrary, they showed hyperfunctional and presecretory state. The G cells were increasing in number six months after operation, and then G cell hyperplasia became more remarkable one year postoperatively. Emiocytotic figures were observed in denervated G cells after SV＋P which were stimulated by meat extract or insulin hypoglycemia. In Parallel with the electron microscopic observations of G cells, the plasma gastrin levels began to be elevated.

　From these findings, G cells could release gastrin in response to stimulation by meat extract and insulin hypoglycemia of ter the SV -~ P when the antrum is conserved. Then hypergastrinemia occurred due to G cells hyperplasia. So, it is necessary to do complete vagotomy on the parietal cell region in case of SV＋P.