The Effect of Transposition to Jejunum on Epithelial Cell Kinetics in an Ileal Segment

Abstract

Epithelial cell kinetics were studied in an ileal segment after transposition to proximal jejunum. The number of cells per villus column in the transposed ileum increased after 4‐7 days to reach values normal for jejunum after 14‐30 days. This increase was accompanied by a simultaneous increase in the number of cells per crypt column up to 130% of values in jejunum and ileum in situ. The percentage of labelled crypt cells, after labelling with 3H‐thymidine, and the relative size of the proliferative cell compartment in the crypt in the transposed ileum did not differ from values in the ileum in situ at any time interval after surgery. The total proliferative activity per crypt, which was determined by scintillation counting of isolated crypts after 3H‐thymidine labelling, increased two‐fold from 7 days after surgery. Cell migration studies showed that the increase in the number of villus cells was probably not caused by a change in the life span of the epithelial cells. It seems that the increase in the number of villus cells in ileal epithelium after transposition to proximal jejunum is brought about by an enlargement of the crypt, while the relative size of the proliferative cell compartment in the crypt remains unchanged.

Development of Jejunoileal Differences of Activity of Lactase, Sucrase and Acid β-Galactosidase in Isografts of Fetal Rat Intestine

“…This is the so-called topographic specialization of the small intestine (4,20). The factors responsible for the expres sion of the jejunoileal gradient have been the subject of numerous studies, in which direct or indirect approaches have been employed (1, 9 -1 1 , 13, 15,29,[31][32][33]. One or both of the following mechanisms are here suggested as pos sible factors:…”

Comparison of Ileal and Jejunal Transplantation after 50% Proximal Intestinal Resection

“…These parameters were greater in the proximal transplanted segment of both groups compared with the proximal jejunum of transection controls. Similarly, in transposition models, the ileum achieves a villus height similar to that of jejunum when interposed proximally, whereas the jejunum loses villus height when moved distally in the gastrointestinal tract [3][4][5][6]. Unlike previous transposition studies, however, the transplanted ileum in the present study was in continuity with an intact ileal remnant.…”

“…Crypt depth was greater, however, in the transplanted groups. Rijke et al [3] found that total proliferative activity was greater in transposed ileum up to 30 days after operation, although the relative size of the proliferative cell compartment was similar. Thus, they found that increased villus height was secondary to an actual increase in the number of proliferating crypt cells rather than any change in migration rate which remained normal.…”

“…Transposition studies suggest that this is, in part, related to an increased exposure of the ileum to nutrients and pancreaticobiliary secretions after proximal resection [3][4][5][6]. However, there may be certain features intrinsic to the ileum, e.g., hormonal content of enterocytes, that contribute to this response as well [4].…”

Intestinal Iron Transfer after Ileojejunal Transposition

“…Related to the segments' length, iron transfer was significantly increased in ileoje-junal transponates as compared to ileal con trols (table 4) 23], i.e. the number of enterocytes on each villus has increased.…”