Crypt Cell Proliferation Rate Research Articles

Salmonella typhimurium and Salmonella enteritidis induce gut growth and increase the polyamine content of the rat small intestine in vivo

The effects of infection by Salmonella enteritidis and S. typhimurium on the small and large intestines, liver, spleen and mesenteric nodules of rats were studied in vivo. Both Salmonella serotypes persisted and proliferated in the gastrointestinal tract and invaded sub-epithelial tissues, mainly the ileum, leading to the systemic distribution of these pathogens. Coincidental with the infection, the rate of crypt cell proliferation increased resulting in substantial growth of the small intestine. The extent of this and the accompanying accumulation of polyamines was particularly dramatic in the ileum where there was also some disruption of the villus epithelium. It is possible that these effects of the infection on the metabolism and morphology of the small bowel, which strongly resembled the changes induced by some plant lectins, may facilitate the colonisation and invasion of the gut by Salmonellae.

Dietary ω-3 fats reduce proliferation and tumor yields at colorectal anastomosis in rats

Background & Aims: Colorectal anastomoses show increased mucosal crypt cell proliferation rates (CCPRs) and often form the site for tumor recurrence after resection of colorectal cancer. The aim of this study was to assess the effects of a 20% ω-3 fat diet on CCPRs and anastomotic tumor formation compared with an isocaloric 20% saturated fat diet in experimental colorectal cancer. Methods: One hundred sixty male Wistar rats were administered azoxymethane or saline for 6 weeks, after which a colonic anastomosis or sham operation was performed. CCPR, mucosal fatty acids, and tumor yield were analyzed at the anastomosis and proximal and distal colon sites at 15 and 23 weeks. Results: Diet, carcinogen treatment, and surgery all had significant effects on CCPR with ω-3 fats producing the lowest CCPR at all sites. There were fewer tumors ( P < 0.02), including a marked reduction of anastomotic tumors in ω-3 fat-fed animals that was associated with a significant reduction of arachidonic acid in mucosal and tumor lipids. Conclusions: Dietary ω-3 fat significantly reduced colonic CCPR and tumor yield, including at the site of anastomosis. Dietary ω-3 fats may be of value to patients after colorectal resection and anastomosis for cancer and warrant further testing.

The long-term effect of pinealectomy on the crypts of the rat gastrointestinal tract.

Previously it has been found that rat small bowel crypt cell hyperplasia occurred several weeks after pinealectomy. To determine if this effect was longer-lasting (because of the possible role of the pineal in bowel malignancy) the crypt cell proliferation rate was determined in rat small bowel and colon 6 months after pinealectomy, using a stathmokinetic technique. Although the hyperproliferative effect of pinealectomy was well maintained in the small bowel crypts after 6 months, the hyperproliferative effect in the colonic crypts was much less marked. There is no obvious explanation for these findings, although it is possible that regional differences in levels of gut neuropeptides or melatonin are involved. The mechanism of the effect of pinealectomy on the crypts remains unexplained--in particular, why the effect is so prolonged.

The role of lympho-epithelial interactions in the regulation of small intestinal epithelium proliferation.

There is evidence that immune system participates in the regulation of intestinal epithelial proliferation and differentiation. It has been proposed1 that activated T lymphocytes affect crypt cell turnover through release of soluble products, i. e., lymphokines. This point of view has more recently received additional experimental confirmation. It was shown2 that Con-A-stimulated intraepithelial lymphocytes and spleen cells suppress growth and modulate la expression by intestinal epithelial cell line. The stimulation of T lymphocytes with pokeweed mitogen or anti-CD3 monoclonal antibodies applied to intestinal organ culture enhanced the rate of crypt cell proliferation.3 Lymphocyte culture supernatants modulate [3H]-thymidine ([3H]TdR) incorporation into isolated small intestinal crypt cells.4 There are also data suggesting that lymphocytes induce formation of M cells5 and regulate Goblet cell development.6 The involvment of immune factors in regulation of intestinal epithelium functions is supported by data on Interleukin-6 receptor expression in intestinal epithelial cells.7

Polyunsaturated fatty acids of the n - 3 series influence intestinal crypt cell production in rats.

The effects of saturated and polyunsaturated dietary lipids on intestinal mucosal cell proliferation were investigated in rats. Animals were randomly allocated to three groups of 10, and fed fibre-free diets containing lipid in the form of lard, corn oil or fish oil at a level of 80 g/kg. Total energy intake was kept constant by pair-feeding. After 14 days the crypt cell production rates (CCPR) at two sites in the small intestine, one site in the caecum and two sites in the colon were determined by the metaphase arrest technique, together with circulating levels of enteroglucagon and gastrin and parameters of mucosal morphology. Consumption of fish oil led to lower CCPR compared to corn oil at all sampling positions except the caecum (Treatment approximately 50% of control values; P < 0.05). In animals fed lard the CCPR in the small bowel was not significantly different to that of animals fed corn oil but their rates were lower in the colon. Post-prandial enteroglucagon and gastrin levels were lower in animals fed fish oil compared to the other two groups. These results suggest that polyunsaturated fatty acids of the n - 3 series may support a relatively low rate of crypt cell proliferation in some regions of the alimentary tract and might thereby tend to suppress the progression of colorectal neoplasms.

Baked Rye Products Modify Cholesterol Metabolism and Crypt Cell Proliferation Rates in Rats

Young adult male rats were made hypercholesterolemic by feeding cholesterol (+ cholic acid). The effect of rye crispbread on hepatic and plasma cholesterol concentrations, hepatic cholesterol synthesis, small intestinal cell turnover and fecal output was investigated. Diets containing 50 and 75% rye crispbread (g dry wt) were compared with positive control diets of similar gross composition, in which the insoluble component of rye was matched with cellulose and the soluble component with guar gum. A negative control diet containing no non-starch polysaccharide was also included. Cholesterol supplementation was maintained in half the rats on each diet. Rye caused a marked increase in fecal output that was greater than that seen in the positive control groups. However, crypt cell proliferation in the small intestine was less than that seen in the high fiber control groups. Rye reduced total plasma cholesterol concentrations only in those rats that continued to receive the high cholesterol diet. However, whether or not cholesterol was fed, the presence of nonstarch polysaccharide caused a decrease in liver cholesterol concentrations. Rye caused a marked increase in hepatic cholesterol synthesis over both the positive controls and the rats fed a fiber-free diet. This implies that rye causes a loss of cholesterol from the body, probably due to malabsorption of bile acids and cholesterol.

Gastrointestinal responses to oats consumption in young adult and elderly rats: digestion, large bowel fermentation and crypt cell proliferation rates

The present experiment was designed to test the hypothesis that ageing modifies the gastrointestinal responses to a change in diet composition. Rats of the Wag/Rij strain, either young adult (4 months of age) or elderly (27 months of age), were given a basal semi-purified diet or a diet of similar major nutrient composition containing 500 g oatmeal/kg for 17-18 d. Elderly rats digested the dry matter (DM) and organic matter (OM) of both diets less well than did their young adult counterparts, with more of this digestion occurring in the distal intestine. The greater flow of OM to the caecum of oats-fed animals was accompanied by significant reductions in caecal pH and increases in caecal total short-chain fatty acids (SCFA) concentration which appeared to be independent of age. However, young adults responded to feeding on oats by showing a much larger increase in the molar proportion of butyrate (332%) than did elderly animals (79%). Elderly rats had longer duodenal villi than did young adults but effects of age or diet were not detectable at other sites. With both age-groups oats consumption was associated with significant stimulation of crypt cell proliferation rate (CCPR) in the small intestine and caecum, but for the colon there was a significant reduction in CCPR with oats feeding. A reduced ability of the aged large bowel (LB) to produce butyrate may contribute to the prevalence of LB disorders in the elderly.

The Influence of the Interaction of Sutures with the Mucosa on Tumour Formation at Colonic Anastomoses in Rats

In order to explore the respective role of wound healing and suture material on metachronous carcinogenesis at colonic lines in rats, tumour yield was studied after the administration of a chemical carcinogen (azoxymethane) at the moment that in one group of rats most of the suture material was still present and crypt cell proliferation elevated, while in another group, no more suture material was present and crypt cell proliferation rate (CCPR) normalized at the anastomotic site. Azoxymethane (15 mg/kg/week, s.c., during 6 weeks) was administered in male Sprague-Dawley rats (n = 105) 8 weeks after the creation of an anastomosis in the ascending and descending colon with either stainless steel sutures (group A, n = 30) or fast-absorption Vicryl (Vicryl Rapide, group B, n = 30). A control group (group C, n = 30) underwent a sham laparotomy before the administration of azoxymethane, while the animals of a fourth group (group D, n = 15) were not operated upon and received no azoxymethane. Twenty-six weeks after the first injection of azoxymethane there was no significant difference in the total colorectal tumour yield in the three operated groups (A, B, C), but a significantly greater proportion of anastomotic tumours (28/68 vs. 13/88, p < 0.01) and more anastomotic tumours per rat (28/23 vs. 13/28, p = 0.01) as well as more rats with anastomotic tumours (16/23 vs. 11/28, p = 0.04) were found in the steel-sutured group (A), compared with the control group (C).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of pinealectomy and autonomic denervation on crypt cell proliferation in the rat small intestine

Previously it has been found that pinealectomy in rats was associated with increased small bowel crypt cell proliferation. The hypothalamus is thought to play a role in the neural control of crypt cell proliferation and the pineal gland is known to be functionally connected with this component of the autonomic nervous system. Consequently, the effect on crypt cell mitotic rate of pinealectomy with autonomic denervation of the rat small bowel (local sympathectomy and truncal vagotomy) was observed to determine the possible importance of the autonomic nervous system in the mediation of the effects of pinealectomy on the crypts. It was found that interruption of either the vagal or sympathetic nerve supply to the small intestine both significantly decreased the usual hyperproliferative effect on the crypt cells observed after pinealectomy. It is suggested that the overall effect of the pineal gland is to suppress the crypt cell proliferation rate and that this effect is mediated, at least to some extent, by (1) the direct connections between the pineal gland and the hypothalamus, (2) the connections between the hypothalamus and the vagal and sympathetic innervation of the gut, and (3) the influence of the autonomic innervation on the activity of the enteric plexuses in relationship to the crypts. The pineal may have a role in modulating the local control mechanism of crypt cell proliferation. Its exact role in the control of crypt cell proliferation has not yet been defined.

The effects of the Bowman-Birk protease inhibitor on c-myc expression and cell proliferation in the unirradiated and irradiated mouse colon

The levels of c-myc RNA and crypt cell proliferation were monitored in the mouse colonic mucosa following X-irradiation with and without oral administration of the Bowman-Birk protease inhibitor (BBI). Mice were divided into 4 groups and treated as follows: (A) daily gavage with water; (B) daily gavage with BBI; (C) daily gavage with water and 12 Gy of abdominal irradiation 1 day after the first gavage; (D) daily gavage with BBI and 12 Gy of abdominal irradiation 1 day after the first gavage. Samples were collected at various times after X-irradiation and ascending colon samples were taken for crypt cell proliferation analysis. The mucosa was removed from the remaining sample and total cellular RNA was isolated. The levels of c-myc mRNA underwent a time-dependent change following X-irradiation. Expression of the c-myc gene was unchanged at 1 day and 3 weeks after irradiation, but was markedly elevated at 1 week after X-irradiation. BBI was found to suppress the radiation induced elevation of c-myc mRNA, while having no effect on the rate of crypt cell proliferation or body weight of the mice.

The effect of pinealectomy and jejunal loop diversion on rat small bowel crypt cell kinetics

Previously, it was found that diversion of an isolated loop of jejunum into the colon was associated with a significantly diminished crypt cell proliferation rate in the isolated loop, probably principally because of the diminished amount of nutrient available to the diverted mucosa. It has also been shown previously that removal of the pineal gland is associated with a considerable increase in the jejunal crypt cell mitotic rate. In the present investigation it was found that following pinealectomy, whilst the rise in crypt cell proliferation elsewhere in the rat small intestine was maintained at the expected level, the mitotic rate in the crypts of an isolated jejunal loop attached to the colon was also increased to a similar level, despite the fact that this isolated loop was in contact with a considerably diminished level of luminal nutrients. Thus, the expected hypoproliferative effects of jejunal isolation were overridden by the hyperproliferative effects of pinealectomy and the effects of pinealectomy appeared to be independent of the particular changes in luminal environment produced in this experiment. The significance of these findings is discussed in the light of the available literature.

Small intestinal crypt cell proliferation rates are increased in senescent rats.

Our previous studies implied that intestinal epithelial cell replication might be increased in senescent rats. Duodenal, jejunal, and ileal crypt cell production rates (CCPR) were measured in 3-4-mo and 26-28-mo female fed control, 3-day starved and 1-day refed, and in 4-5-mo and 26-28-mo male fed Fischer rats, using the vincristine-induced metaphase arrest technique. Fed aging rats had greater proximal intestinal crypt cell numbers which fell less during starvation than those of young controls. Metaphase accumulation also was higher in aging rat duodenum and jejunum, and CCPR were 30-100% more than in young rats. Starvation reduced CCPR by more than 40% in the duodenum of young, but only by 10% in older animals. Crypt proliferative patterns demonstrated a broadened proliferative zone in aging rats. These combined results directly demonstrate that small intestinal cell production is enhanced in senescent rats and that the nutritional controls of proliferation are blunted.

Colonic Proliferation Is Increased in Senescent Rats

Our previous studies suggested that crypt size enlarged and that proliferation rate might be greater in the small intestine of rats during senescence. Crypt cell numbers and crypt cell proliferation rates, using the vincristine-induced metaphase arrest technique, now have been measured in the colon of aging and young Fischer 344 rats. The proximal colon of 26-28-mo-old unfasted rats had 10% more crypt cells and a higher proliferative rate than 3-4-mo-old young controls. In the distal colon, the crypt cell proliferation rate in aging rats was 56% greater than in the young. A 3-day fast reduced crypt cell proliferation about fourfold in young rats but only by 20% in aging rats. One-day refeeding abruptly increased the crypt cell population and proliferation rate in rats of both age groups. The crypt zone of proliferating cells from aging rats was broader than that seen in young rats. In addition, starvation lowered colonic crypt cell cycling rate much less in aging than in young animals. We conclude that the colons of aging rats demonstrate a hyperproliferative state and a failure to adapt appropriately to changes in food intake. These observations may be relevant to states of altered proliferation that occur in the premalignant colon.

Altered controls of proliferation in proximal small intestine of the senescent rat.

The proximal small intestine responds to starvation by rapidly reducing crypt cell proliferation rate and villus cellularity and to resumption of food intake (refeeding) by abruptly increasing proliferation and the number of villus epithelial cells. We show that villus cellularity responds to starvation and refeeding similarly in young and aging animals. However, as compared to young animals, senescent rats showed increased basal DNA synthetic activity, starvation resulted in a smaller decrease in DNA labeling of crypt cells, and refeeding produced an abrupt broadening of the proliferative zone in older animals without concomitant increased numbers of villus cells. Such altered crypt proliferative responses resemble precancerous changes seen in the colon and the aberrant proliferation found in both small and large intestine after administration of the carcinogen dimethylhydrazine.

Effect of a long-acting analogue of somatostatin, SMS 201-995, on the development of intestinal tumours in azoxymethane-treated rats.

The effect of daily parenteral administration of a long-acting analogue of somatostatin (SMS 201-995) on the development of intestinal tumours and the rate of crypt cell proliferation in azoxymethane-treated rats has been studied. SMS 201-995 had no significant effect on the number of colonic tumours induced. In the duodenum, SMS 201-995 administration was associated with a change in the number of tumours from 1.4/rat in saline-treated animals to 2.4/rat in animals treated for the last third of the study and 2.8/rat in animals treated with SMS for the entire duration of the study (P less than 0.02). SMS had no significant effect on the rate of cell proliferation in the duodenum, ileum or colon. The inhibition of release of gastrointestinal trophic hormones by this analogue of somatostatin thus does not appear to reduce the number of tumours in the intestine of azoxymethane-treated rats.

The effects of serotonin on crypt cell proliferation in the human duodenal mucosa in vitro

Cell kinetic studies on the small bowel mucosa in coeliac disease have shown an increased number of proliferating cells per crypt due to a reduction in the crypt cell cycle time. Similar findings occur in rats after the intraperitoneal injection of serotonin. In vitro studies have therefore been performed to determine whether serotonin influenced cell proliferation in the human duodenal mucosa. Normal mucosal biopsies from 18 patients were cultured for 22 hours, using an organ culture technique. Specimens from 9 patients were cultured in a basic medium and from 9 patients in the basic medium with added serotonin (2mg/ml). After 18 hours a stathmokinetic technique was used to determine the crypt cell proliferation rate (CCPR) by adding vincristine sulphate (1μ/ml) to the culture medium. Tissue samples were removed at hourly intervals for A hours and the mean number of metaphase arrests in 10 whole crypts was determined. The CCPR was derived by drawing a regression line between the mean values obtained on each patient. The results indicate that serotonin significantly increases the CCPR in cultured tissues (p 0.001). Described abnormalities of serotonin synthesis jn coeliac disease may be involved in the pathogenesis of this disorder.

Adrenergic factors involved in the control of crypt cell proliferation in jejunum and descending colon of mouse.

The mitotic rates in the crypts of Lieberkühn of the proximal jejunum and descending colon of mouse, following different treatments, were measured using a stathmokinetic technique. Regression coefficients, representing mitotic rates, were then calculated by the method of least squares. Treatment with adrenaline, isoprenaline, phenylephrine, phentolamine, and yohimbine all resulted in decreased mitotic rate of jejunal and colonic crypt cells. Chemical sympathectomy and cryosympathectomy had a similar effect, and chemical sympathectomy was followed by a supersensitivity to clonidine. Intraperitoneal injection of metaraminol, clonidine, propranolol, prazosin, labetolol and simultaneous injection of propranolol and adrenaline all resulted in an increased rate of crypt cell proliferation in both jejunum and colon. A significant increase in mitotic rate was observed in both tissues at night. The amplitude of this diurnal variation was decreased in both jejunum and colon following chemical sympathectomy. In addition, the amplitude of this variation in jejunum was decreased after treatment with yohimbine or phentolamine. The results of the study suggest that the sympathetic nervous system stimulates epithelial cell proliferation in both the small and large intestine and that this effect is mediated by an alpha 2-adrenoceptor. By contrast, stimulation of alpha 1- and beta-adrenoceptors is inhibitory to cell proliferation in these tissues.

Pattern of crypt cell proliferation in the pre- and post-closure ileum of the neonatal rat: effects of sympathectomy.

The present experiments were designed to investigate ileal crypt cell division before and after neonatal closure to macromolecular absorption by measurements of mitotic index, labelling index, colchicine-induced estimation of mitotic rate (mitoses/cell/hour) and crypt depth and villus height on postnatal days 15--23. In addition, the effects of the sympathetic nervous system on crypt cell proliferation were analyzed by guanethidine-induced sympathectomy. Guanethidine treatment resulted in at least a 70% reduction in superior cervical and coeliac perikarya at 15 days after birth. All cell proliferative indices demonstrated a rather constant rate of cell division in the ileal epithelium between 15 and 17 days after birth with a sudden burst of mitotic activity on day 18. The mitotic rate of control rats increased from day 18 to 23 with 3-week-old rat demonstrating a faster rate of ileal crypt cell proliferation than adult rats. The ileal crypt depth more than doubled between 15 and 23 days while the height of the villus column increased slowly but steadily (36%) during the period of this study. Cell division is inhibited by guanethidine-induced sympathectomy although there is still an acceleration of mitosis in the post-closure period. The relationship of sympathectomy and ileal crypt cell proliferation is discussed and compared to hormonal effects on closure and related developmental events.

Increased mucosal damage during parasite infection in mice fed an elemental diet.

We have examined the effects of parasite infection on the mucosal architecture of mice maintained on an elemental diet (Vivonex). Techniques used were conventional histology, micro-dissection and measurement of individual villi and crypts, and measurement of crypt cell proliferation rate by a metaphase accumulation technique. In normal, non-parasitised mice the elemental diet caused no change in villus height, crypt depth, or crypt cell proliferation. Likewise, the only effects of chronic protozoal infection or Nippostrongylus brasiliensis infection on the intestine of mice fed a normal diet have been a slight crypt hypertrophy and an increase in crypt cell proliferation rate without villous atrophy. However, the combination of elemental diet and parasite infection resulted in increased mucosal damage when compared with infected mice on a normal diet. Elemental diet mice infected with the nematode Nippostrongylus brasiliensis had significantly reduced villus height and correspondingly raised crypt length and metaphase accumulation rate. Elemental diet mice infected with the protozoan Giardia muris did not have villous atrophy but there was a significant increase in crypt length and metaphase accumulation when compared with infected normal diet mice. These experiments show that in two animal models of enteric infection, elemental diet has altered the host parasite relationship to the detriment of the host.