Bax is required for resection-induced changes in apoptosis, proliferation, and members of the extrinsic cell death pathways

Influence of the site of small bowel resection on intestinal epithelial cell apoptosis

“…Analysis of gene and protein expression of selected members of intrinsic and extrinsic apoptotic pathways revealed that their expression profiles vary greatly along the proximal-distal axis of the gut. We found that after P-SBR both bax and Fas gene expression were up-regulated; and that these findings are supported by previous studies (11,13). However, tumor necrosis factor alpha (TNF-α) was the only factor found to be up-regulated at 7 days after D-SBR.…”

“…In our study, mice lost significantly less weight after P-SBR compared to D-SBR, which also suggests a greater adaptive capacity of ileum compared to jejunum. Morphologic adaptation after SBR has been shown to be driven by changes in crypt cell proliferation and enterocyte apoptosis rates (11,13,21). In the rapidly proliferating intestinal epithelium the ratio between enterocyte proliferation and apoptosis is responsible for maintenance, enhancement or loss of intestinal absorptive function (22).…”

“…Several studies have recently shown that EC apoptosis is increased in the frame of intestinal adaptation after P-SBR, and emphasized that bax is the major protein that drives increased EC apoptosis after SBR (11,24,25). On the other hand, others have also reported an increased expression of Fas, another potent inducer of apoptosis over the death receptor pathway after P-SBR (13). This suggests that not only the bcl-2 family but also the members of the extrinsic apoptotic pathway are involved in regulation of post-resectional EC apoptosis.…”

“…Recently, increased rates of enterocyte apoptosis have been reported after massive SBR, indicating that not only crypt cell proliferation, but also enterocyte apoptosis may play the crucial role during the process of post-resectional intestinal adaptation (11)(12)(13). The importance of crypt cell apoptosis is elucidated by the fact that the death of one crypt cell may be responsible for the loss of more than 100 descendent crypt enterocytes (14).…”

Increased apoptosis and accelerated epithelial migration following inhibition of hedgehog signaling in adaptive small bowel postresection

“…in villus hyperplasia, increased enterocyte migration from crypt to villus tip, and enhanced nutrient absorption (12,20,37). We and others have shown that crypt cell apoptosis is also modified during the adaptive response (13,37).…”