Intestinal selenoprotein P in epithelial cells and in plasma cells.

The micronutrient selenium and selenium-containing selenoproteins are involved in prevention of inflammation and carcinogenesis in the gut. Selenoprotein P (Sepp1), the plasma selenium transport protein, is secreted primarily from hepatocytes, but Sepp1 mRNA is also abundant in the intestine. By immunofluorescence analysis, we show that Sepp1 levels in epithelial cells of the rat jejunum increase along the crypt-to-villus axis. A different Sepp1 distribution pattern was observed in the rat colon, where the epithelial cells located at the base and at the top of the crypts were similarly positive for Sepp1. In addition, we found pronounced Sepp1 immunoreactivity in CD138-positive plasma cells scattered within the lamina propria of the colon. This hitherto unrecognized presence in terminally differentiated B-cells was corroborated by detection of Sepp1 in plasma cells residing in the rat spleen. Following supplementation with dietary selenium compounds, polarized intestinal epithelial Caco-2 cells secreted Sepp1 into the culture medium across the basolateral membrane. Our data suggest that Sepp1 secreted from epithelial cells may support the intestinal immune system by providing immune cells (including plasma cells) with selenium for the biosynthesis of endogenous selenoproteins.

Dose-dependent reduction of dietary protein-induced colonocyte DNA damage by resistant starch in rats correlates more highly with caecal butyrate than with other short chain fatty acids.

Previous studies have shown increased levels of colonocyte DNA damage (as measured by the comet assay) and thinning of the colonic mucus layer in rats fed higher dietary protein as casein or red meat with highly digestible starch. Feeding resistant starch (RS) as high amylose maize starch (HAMS) opposed these changes. However, the dietary level of HAMS was relatively high (48% by weight) so this study was conducted to establish whether HAMS had the same effects at lower dietary levels. Adult male rats were fed a diet containing 25% casein with 0%, 10%, 20%, 30% or 40% HAMS for 4 wk. DNA single strand breaks and 8-hydroxyguanosine levels were measured in isolated colonocytes by the comet assay. As expected, comet tail moment was greatest and the mucus barrier thinnest in rats fed 0% HAMS. DNA damage was reduced and the mucus barrier thickened in a logarithmic dose-dependent manner by HAMS. There was no significant difference in 8-hydroxyguanosine between dietary groups. Caecal and fecal short chain fatty acid (SCFA) pools rose with the increased level of dietary HAMS. DNA damage of colonocytes correlated negatively with caecal SCFA but the strongest correlation was with caecal butyrate, which is consistent with the proposed role of this SCFA in promoting a normal cell phenotype. These data show that HAMS prevents protein-induced colonic DNA damage in a dose-dependent manner. Inclusion of 10% HAMS was found to be sufficient to oppose colonocyte DNA damage, and to increase caecal and fecal SCFA pools.

Suppression of Th2-type immune response-mediated allergic diarrhea following oral administration of traditional Korean medicine: Atractylodes macrocephala Koidz.

Atractylodes macrocephala Koidz (AMK) is well-known as a digestive and tonic material and is widely used in traditional Korean herbal medicines. Previously, we found that protein samples obtained from the medicines could induce a preferential stimulation of type 1, rather than type 2, helper T lymphocytes (Th) immune responses in vitro. Since immune response induction is controlled by the balanced activation between Th1- and Th2-type immune responses, we tested to see whether or not the AMK protein sample could inhibit the ovalbumin (OVA)-mediated allergic diarrhea, whose induction has been known to be mediated by the Th2-type immune responses. The sample treatment markedly stimulated lymphocyte proliferation, antibody production, and cytokine secretion in vitro, showing a preferential stimulation of Th1-type immune responses. In particular, oral administration of the AMK sample suppressed the OVA-mediated allergic diarrhea in mice. The sample treatment also suppressed the OVA-mediated enhanced levels of total immunoglobulin (Ig) E, as well as OVA-specific IgE, which are closely associated with Th2 cell stimulation in mice. Furthermore, the oral treatment of the sample significantly increased gamma interferon (IFN-gamma) production by lymphocytes, isolated from spleen and large intestine of the mice, that had been systematically challenged with OVA. Consequently, the oral administration of AMK protein sample suppressed the OVA-mediated allergic diarrhea by preferential stimulation of the Th1-type immune responses.

Prebiotic carbohydrates modify the mucosa associated microflora of the human large bowel.

BACKGROUND AND AIMS: The mucosa associated flora of the large intestine is important in determining mucosal function although what controls its composition is unknown. This study has determined the effect of the prebiotic carbohydrates oligofructose and inulin on the mucosal flora. METHODS: An in vitro chemostat model of both planktonic and surface associated bacteria was used followed by an intervention study in 29 subjects undergoing colonoscopy. SUBJECTS: Fourteen subjects, recruited from colonoscopy waiting lists, supplemented their diet for two weeks with a mix of 7.5 g of oligofructose and 7.5 g inulin. Fifteen subjects were recruited at the time of colonoscopy and given no supplement. Multiple endoscopic biopsies were taken from the caecum, transverse and descending colon, and rectum. The mucosal flora was characterised by culture and to species level by cellular fatty acid profiles. Cell proliferation was assessed by immunohistochemical staining for minichromosome maintenance protein 2, Ki67, and proliferating cell nuclear antigen. RESULTS: In vitro prebiotics increased surface counts of bifidobacteria from 6.6 to 7.3 log(10) colony forming units (CFU) per slide (p<0.0006) with no significant changes in planktonic bacteria. In the feeding study, prebiotics increased mucosal bifidobacteria (log CFU/g mucosa (SEM)) in both the proximal (control 5.3 (0.4) v prebiotic 6.3 (0.3)) (p = 0.059) and distal (control 5.2 (0.3) v prebiotic 6.4 (0.3)) colon (p = 0.01). Lactobacilli were also increased (3.0 (0.1) v 3.7 (0.2) (p = 0.02) in the proximal and 3.1 (0.1) v 3.6 (0.2) (p = 0.04) in the distal colon, respectively). There were significantly more eubacteria in fed subjects but no changes in total anaerobes clostridia, bacteroides, or coliforms, nor in proliferation indices. CONCLUSION: Prebiotic carbohydrates can change the composition of the mucosa associated flora significantly.

Increases in the concentrations of available iron in response to dietary iron supplementation are associated with changes in crypt cell proliferation in rat large intestine.

High concentrations of iron in the diet have been shown to increase chemically induced colorectal tumors in rats. It is therefore important to understand the influence of dietary iron on the concentration of unabsorbed iron in the large intestine and its distribution between soluble and insoluble pools in the luminal compartment. We sought to investigate this issue and to establish whether iron modifies mucosal cell proliferation, which is thought to influence initiation and progression through the adenoma carcinoma sequence. In the first experiment, four groups of seven rats were fed diets at two concentrations of iron, 29 and 102 mg/kg, with or without the addition of 2.5 g phytic acid/kg. The concentrations of iron in the contents of the large bowel extractable with water ("free iron") or a buffered EDTA solution ("exchangeable iron") were determined. The concentration of freely soluble iron increased approximately 100% with iron supplementation in both the cecum and the colon, and there was an approximately five- to sixfold increase in exchangeable iron at both sites (P < 0. 05). In a second experiment with identical feeding conditions, there was a significantly greater number of cell divisions per crypt in the colon of the high iron group and a significantly greater number of cell divisions in the upper part of the crypt in the cecum. The concentrations of free and exchangeable iron observed in colonic contents in this study are consistent with those reported by others to increase free radical production in fecal material. Further studies are required to determine whether the small changes in crypt cytokinetics are a consequence of oxidative mucosal damage.

[Protective effects of glutamine and elemental diet in acute actinic enterocolitis: histological evaluation]. / Efeitos protetores da glutamina e dieta elementar na enterocolite actínica aguda: avaliação histológica.

Radiotherapy plays nowadays an important role in malignancies treatment. However, collateral effects and severe complications owing to cellular damage of peritumoral tissues may occur. Different nutritional resources have been recently indicated to achieve intestinal protection during cancer irradiation. PURPOSE--The aim of this study was to set the role of glutamine and elemental diets in acute actinic enteritis prevention. METHOD--Sixty-five adult male Wistar rats with average weight of 200g were maintained in individual metabolic cages; daily body weight and food ingestion were carefully monitored. The animals were randomized into three groups and fed isocaloric and isonitrogenous diets: 1) CRt-polymeric-casein diet; 2) GRt-polymeric-casein diet supplemented with 2% glutamine and 3) ERt-elemental diet supplemented with 2% glutamine. After an adaptation period (seven days), all rats received abdominal radiation in five daily doses of 300cGy. Four days after the rats were operated on to resect the small intestine and colon for histological evaluation. RESULTS--Small intestine histological data in ERt and GRt rats were better than CRt rats, by preserving mucosal cellularity and increasing mitosis number and villi length. Simultaneously, ERt group had greater number of rats with normal villus-crypt relation than CRt or GRt groups. Large intestine histological data showed that the average crypts length in ERt and GRt rats were greater than in CRt ones. CONCLUSION--Glutamine-supplemented polymeric or elemental diets given to rats before, during and after abdominal radiotherapy showed protective effects against radiation injury, by supporting mucosal structure and recovery.

Reduction of tetrachloro(dl-trans)1,2-diaminocyclohexaneplatinum(IV) (tetraplatin) toxicity by the administration of diethyldithiocarbamate (DDTC), S-2(3-aminopropylamino)ethylphosphorothioic acid (WR-2721), or sodium selenite in the Fischer 344 rat.

Diethyldithiocarbamate (DDTC), S-2(3-aminopropylamino)ethylphosphorothioic acid (WR-2721), and sodium selenite have all been shown to effectively reduce cisplatin toxicity. As a result, we have investigated the efficacy of these compounds to reduce the toxicity associated with tetrachloro(dl-trans)1,2-diaminocyclohexaneplatinum(IV) (tetraplatin), a second-generation platinum compound recently approved for phase I/II clinical trials. The dose-limiting toxicities associated with tetraplatin (16.5 mg/kg) in the Fischer 344 male rat were nephrotoxicity, myelosuppression, and gastrointestinal toxicity. The nephrotoxicity in Fischer 344 rats was effectively reduced by treatment with either DDTC (750 mg/kg ip) 0.5 hr after tetraplatin or WR-2721 (200 mg/kg ip) 0.5 hr before tetraplatin as determined by blood urea nitrogen and creatinine values. Diarrhea was evident in 95% of the rats treated with tetraplatin alone while it was not evident in any of the DDTC- or WR-2721-protected rats. Only DDTC was moderately effective in preventing tetraplatin-induced decreases in platelet and lymphocyte counts. Histopathology confirmed DDTC protection of renal, intestinal, and lymphoid tissues and WR-2721 protection of renal and intestinal tissues. Sodium selenite was ineffective in reducing tetraplatin-induced damage when administered 4 hr before tetraplatin at doses of 0.5, 1.0, or 2.0 mg/kg. The results suggest that DDTC may allow for increased dosages of tetraplatin by ameliorating the toxic side effects of the drug. WR-2721 may also have some usefulness in tetraplatin therapy, but it does not reduce as wide a variety of toxic side effects as DDTC.