Hypertrophy of the small intestine after its partial resection in the rat

Skála, I; Konrádová, V

doi:10.1007/bf02235879

Cited by 17 publications

(9 citation statements)

References 14 publications

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“…An observation that resection was followed by marked increases in the thickness of lateral cell membranes and microvillus tubules (48) has not been substantiated from two other laboratories (49,50). While this merits further examination, the data in the present study, showing the relative constancy of the percentage of total activity associated with the particulate fraction, are in keeping with the conclusion that microvillus membranes are morphologically unchanged in the hyperplastic tissues.…”

Section: Discussionmentioning

confidence: 98%

Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

McCarthy¹,

Kim²

1973

J. Clin. Invest.

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A B S T R A C T In a study of changes in digestive enzymes after massive intestinal resection and the mechanisms by which such changes occur, rats were sacrificed 4 wk after removal of the proximal two-thirds of the small intestine. Alterations in the mucosal levels of sucrase, enterokinase, and dipeptide hydrolase (Lleucyl-L-alanine substrate) were examined in the light of associated changes in protein, DNA and wet mucosal weight, measured in standardized gut segments from various regions of intestine.Metabolic studies showed that normal growth patterns were reestablished after the operation but significant elevations in stool weight and fecal nitrogen occurred in the second postoperative week, falling towards normal by the 4th wk. In standard gut segments wet weight of mucosa, protein, and DNA rose, especially in distal segments, DNA increasing disproportionately. Mucosal levels of the proximally distributed and membranebound enzymes, sucrase and enterokinase, showed similar patterns of change: when enzyme activity was expressed in terms of the total per segment, proximally there were considerable increases in both enzymes, but, expressed in terms of specific activity, that of sucrase fell and that of enterokinase was unaltered. By contrast, the largely soluble and more distally distributed dipeptide hydrolase increased more in distal segments and the increases in total activity were accompanied by lesser increases in specific activity. However, in spite A preliminary report of this work was presented to The

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Section: Discussionmentioning

confidence: 98%

Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

McCarthy¹,

Kim²

1973

J. Clin. Invest.

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“…Morphometric data on the other subcellular organelles of the absorptive cells are completely lacking. However, a number of qualitative observations are available [7,9,23,24,32], but again with conflicting results.…”

Section: Introductionmentioning

confidence: 93%

Early ultrastructural adaptive changes of ileal enterocytes after proximal small bowel resection as determined morphometrically

1985

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The aim of the present study was to evaluate in terms of quantitative measurements whether the well-known histomorphological and functional adaptive changes in the intestinal mucosa after small bowel resection are accompanied by alterations on the ultrastructural level. Therefore, samples of the ileal remnants after a 60% proximal resection were processed for ultrastructural evaluation and analyzed employing point counting planimetry and direct measurements. Microvillus surface area increased from the bottom of the crypts to the villus tips in both resected and sham-operated animals. This increase in microvillus surface area from the crypt to the villus was significantly less pronounced after proximal resection, while there were no changes in the crypt compartment. No significant differences of the relative areas of the nuclei, mitochondria, and the rough endoplasmic reticulum were observed when comparing the different positions along the villus crypt axis in normal and hyperplastic mucosa. In agreement with functional and enzyme histochemical results, these ultrastructural findings provide further evidence for an altered pattern of enterocyte maturation after proximal resection, which is most probably due to an increase in the migration rate of the enterocytes.

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“…Hyperplasia has also been noted in residual rat intestine 2 months after 70% midsmall bowel resection [25], Electron microscopic studies of the epithelial cells in the residual small bowel after resection have provided conflicting results. Two studies suggested that the ultrastructure of rat ileum following a 50-cm jejunal resection [49] and of the residual beagle small intestine 1 year after a 90-percent enterectomy [61] was normal. Similarly, Dowling [14] found noconsistent changes in the ultrastructure of epithelial cells in jejunal biopsies from patients with extensive distal small bowel resection.…”

Section: Hyperplasia or Hypertrophymentioning

confidence: 99%

Cell Turnover Following Small Bowel Resection and By-Pass

Dowling¹,

Gleeson²

1973

Digestion

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Changes in epithelial cell turnover play a central role in the regenerative response of the residual small intestine after partial small bowel resection. This article reviews these changes both in experimental animals and in man and discusses how alterations in cell turnover may influence villous morphology, the enzyme content of the cells and the absorptive and digestive function of the small bowel mucosa. Increased absorption per unit length of intestine has now been well documented after small bowel resection, and current evidence suggests that this is largely mediated by an increased absorptive surface produced by villus enlargement. In turn, the elongation of the villi seems to be due to hyperplasia with an increased number of cells rather than to hypertrophy of the individual cells. The villus hyperplasia is associated with an increased rate of cell migration although the cell turnover time may not be shorter than normal because the more rapidly migrating cells must traverse a greater distance before reaching the villus tips. Although absorption, per unit length of bowel, is increased after resection, the function of the individual cells appears normal or may actually diminish, presumably as a result of functional immaturity produced by more rapid cell migration from the nursery of the crypt to the adult world of the villus. Thus, when mucosal transport or cell enzyme content is expressed per mg of mucosal homogenate, per mg protein or per mg of DNA, there is either no change after resection, or the levels may even be reduced. The changes in cell turnover with the attendant effects on villous morphology, cell enzymes and absorptive function are all much greater in ileum than in jejunum. The mechanisms for the altered rate of cell turnover after resection are discussed. Intraluminal or topical nutrition, hormonal factors, the secretion of trophic substances in bile and pancreatic juice and changes in intestinal blood flow have all been proposed as factors responsible for the compensatory hyperplasia. It is suggested that studies of cell turnover after resection are of fundamental importance in understanding the controlling mechanisms of normal growth in the small intestine.

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Hypertrophy of the small intestine after its partial resection in the rat

Cited by 17 publications

References 14 publications

Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

Changes in Sucrase, Enterokinase, and Peptide Hydrolase after Intestinal Resection THE ASSOCIATION OF CELLULAR HYPERPLASIA AND ADAPTATION

Early ultrastructural adaptive changes of ileal enterocytes after proximal small bowel resection as determined morphometrically

Cell Turnover Following Small Bowel Resection and By-Pass

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