Metabolic surgery can promote comprehensive physiological improvements to alleviate metabolic disorders, particularly for patients with type 2 diabetes. Nevertheless, the therapeutic scope has been limited owing to unexpectedly inconsistent surgical outcomes. Therefore, this study to overcome these obstacles by determining the fundamental mechanism underlying the conflicting outcomes. The surgical anatomy, clinical course, and outcomes of various metabolic surgeries, including modified duodenal-jejunal bypass (DJB) procedures, were compared to understand the specific surgical patterns from different perspectives comprehensively. Patients in the nonobese group were exclusively included to prevent confounding effects from overweight patients with type 2 diabetes. Following intestinal anastomosis, the epithelial identity of the succeeding intestine was replaced by that of the proximal epithelium owing to altered crosstalk between the epithelium and opposing mesenchymal cells. Subsequent intestinal compensatory proliferation and rapid turnover rate accelerate the spread of the replaced epithelium. The main factors contributing to inconsistent outcomes of metabolic surgery are inadequate duodenal exclusion and inappropriate biliopancreatic limb length. Replacement of enteroendocrine cells during regeneration can lead to inconsistent outcomes in metabolic surgery. The type and density of enteroendocrine cells distributed at the terminal end of the proximal intestine play a significant role in diverse outcomes of metabolic surgery.

Metabolic surgery can promote integrated physiologic improvement to ameliorate metabolic illness, particularly type 2 diabetes. Nevertheless, the therapeutic scope has been limited by unexpectedly inconsistent surgical outcomes. Therefore, the purpose of this study is to overcome the obstacles by determining the core mechanism of conflicting results. The surgical anatomy, clinical course, and outcomes of various metabolic surgeries, including modified types of duodenal-jejunal bypass procedures, were compared to comprehend specific surgical patterns from distinctive perspectives. Patients in exclusively nonobese groups are subjected to avoid compounding by weight fluctuations. During intestinal anastomosis, the epithelial identity of the succeeding intestine is replaced by that of the proximal epithelium through altered crosstalk between the epithelium and opposing mesenchymal cells. The rapid turnover rate and compensatory proliferation of the succeeding intestine accelerate the propagation of the replaced epithelium. Propagation of replaced epithelium could provoke inconsistent outcomes of metabolic surgery. The major determinants of the conflicting results of metabolic surgery are inadequate duodenal exclusion and inappropriate length of the biliopancreatic limbs. The replaced enteroendocrine cells during regeneration provoke inconsistent outcomes of metabolic surgery. The critical factors are the type and density of enteroendocrine cells distributed at the terminal end of the preceding proximal intestine.