| 1. |
- Schepens, Marloes A. A., et al.
(författare)
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Supplemental calcium attenuates the colitis-related increase in diarrhea, intestinal permeability, and extracellular matrix breakdown in HLA-B27 transgenic rats
- 2009
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 139:8, s. 1525-1533
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Tidskriftsartikel (refereegranskat)abstract
- We have shown in several controlled rat and human infection studies that dietary calcium improves intestinal resistance and strengthens the mucosal barrier. Reinforcement of gut barrier function may alleviate inflammatory bowel disease (IBD). Therefore, we investigated the effect of supplemental calcium on spontaneous colitis development in an experimental rat model of IBD. HLA-B27 transgenic rats were fed a purified high-fat diet containing either a low or high calcium concentration (30 and 120 mmol CaHPO4/kg diet, respectively) for almost 7 wk. Inert chromium EDTA (CrEDTA) was added to the diets to quantify intestinal permeability by measuring urinary CrEDTA excretion. Relative fecal wet weight was determined to quantify diarrhea. Colonic inflammation was determined histologically and by measuring mucosal interleukin (IL)-1beta. In addition, colonic mucosal gene expression of individual rats was analyzed using whole-genome microarrays. The calcium diet significantly inhibited the increase in intestinal permeability and diarrhea with time in HLA-B27 rats developing colitis compared with the control transgenic rats. Mucosal IL-1beta levels were lower in calcium-fed rats and histological colitis scores tended to be lower (P = 0.08). Supplemental calcium prevented the colitis-induced increase in the expression of extracellular matrix remodeling genes (e.g. matrix metalloproteinases, procollagens, and fibronectin), which was confirmed by quantitative real-time PCR and gelatin zymography. In conclusion, dietary calcium ameliorates several important aspects of colitis severity in HLA-B27 transgenic rats. Reduction of mucosal irritation by luminal components might be part of the mechanism. These results show promise for supplemental calcium as effective adjunct therapy for IBD.
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| 2. |
- van Ampting, Marleen T. J., et al.
(författare)
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Damage to the intestinal epithelial barrier by antibiotic pretreatment of salmonella-infected rats is lessened by dietary calcium or tannic acid
- 2010
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 140:12, s. 2167-2172
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Tidskriftsartikel (refereegranskat)abstract
- Perturbation of the intestinal microbiota by antibiotics predisposes the host to food-borne pathogens like Salmonella The effects of antibiotic treatment on intestinal permeability during infection and the efficacy of dietary components to improve resistance to infection have not been studied Therefore we investigated the effect of clindamycin on intestinal barrier function in Salmonella-infected rats We also studied the ability of dietary calcium and tannic acid to protect against infection and concomitant diarrhea and we assessed intestinal barrier function Rats were fed a purified control diet including the permeability marker chromium EDTA (CrEDTA) (2 g/kg) or the same diet supplemented with calcium (4 8 g/kg) or tannic acid (3 75 g/kg) After adaptation rats were orally treated with clindamycin for 4 d followed by oral infection with Salmonella enteritidis Two additional control groups were not treated with antibiotics and received either saline-or Salmonella Urine and feces were collected to quantify intestinal permeability diarrhea cytotoxicity of fecal water and Salmonella excretion In addition Salmonella translocation was determined Diarrhea CrEDTA excretion and cytotoxicity of fecal water were higher in the clindamycin-treated infected rats than in the non-clindamycin treated infected control group Intestinal barrier function was less in the Salmonella-infected rats pretreated with antibiotics compared with the non-clindamycin treated rats Both calcium and tannic acid reduced infection-associated diarrhea and inhibited the adverse intestinal permeability changes but did not decrease Salmonella colonization and translocation Our results indicate that calcium protects against intestinal changes due to Salmonella infection by reducing luminal cytotoxicity whereas tannic acid offers protection by improving the mucosal resistance J Nutr 140 2167-2172 2010
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| 3. |
- van Ampting, Marleen T. J., et al.
(författare)
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Intestinal barrier function in response to abundant or depleted mucosal glutathione in Salmonella-infected rats
- 2009
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Ingår i: BMC Physiology. - London : BioMed Central. - 1472-6793. ; 9, s. 6-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Glutathione, the main antioxidant of intestinal epithelial cells, is suggested to play an important role in gut barrier function and prevention of inflammation-related oxidative damage as induced by acute bacterial infection. Most studies on intestinal glutathione focus on oxidative stress reduction without considering functional disease outcome. Our aim was to determine whether depletion or maintenance of intestinal glutathione changes susceptibility of rats to Salmonella infection and associated inflammation.Rats were fed a control diet or the same diet supplemented with buthionine sulfoximine (BSO; glutathione depletion) or cystine (glutathione maintenance). Inert chromium ethylenediamine-tetraacetic acid (CrEDTA) was added to the diets to quantify intestinal permeability. At day 4 after oral gavage with Salmonella enteritidis (or saline for non-infected controls), Salmonella translocation was determined by culturing extra-intestinal organs. Liver and ileal mucosa were collected for analyses of glutathione, inflammation markers and oxidative damage. Faeces was collected to quantify diarrhoea. RESULTS: Glutathione depletion aggravated ileal inflammation after infection as indicated by increased levels of mucosal myeloperoxidase and interleukin-1beta. Remarkably, intestinal permeability and Salmonella translocation were not increased. Cystine supplementation maintained glutathione in the intestinal mucosa but inflammation and oxidative damage were not diminished. Nevertheless, cystine reduced intestinal permeability and Salmonella translocation. CONCLUSION: Despite increased infection-induced mucosal inflammation upon glutathione depletion, this tripeptide does not play a role in intestinal permeability, bacterial translocation and diarrhoea. On the other hand, cystine enhances gut barrier function by a mechanism unlikely to be related to glutathione.
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| 4. |
- Logue, Jürg Brendan, et al.
(författare)
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Relationship between sediment organic matter, bacteria composition, and the ecosystem metabolism of alpine streams
- 2004
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Ingår i: Limnology and Oceanography. - 0024-3590 .- 1939-5590. ; 49:6, s. 2001-2010
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Tidskriftsartikel (refereegranskat)abstract
- We tested whether sediment bacteria abundance (4´,6-diamidino-2-phenylindole–stained cell counts) were related to sediment organic content (ash-free dry mass [AFDM]) in 11 nonforested streams of three different Alpine catchments during summer 2003. We used terminal restriction fragment–length polymorphism (T-RLFP, a moleculargenetic technique) to test for seasonal and spatial differences in bacterial composition in these same streams. We then related the above parameters, in conjunction with periphyton biomass and hyporheic respiration, to whole stream estimates of gross primary production (GPP) and ecosystem respiration (ER) in a glacial and nonglacial stream, representing environmental extremes, in one of the catchments. The percentage of organic matter of sediments was 4–14% (0.01–0.04 g AFDM ml sediment-1), and counts of bacteria cells per millimeter of sediment averaged 2x10^6–4x10^6. Bacteria counts correlated with sediment AFDM only for streams in the catchment with highest sediment AFDM levels. Bacteria composition (based on the presence and absence of terminal restriction fragments from T-RFLP analysis) changed seasonally in the different streams and differed between glacial- and groundwater-fed streams. In the one catchment, hyporheic respiration averaged 0.0004 and 0.0003 g O2 h-1 kg sediment-1 and was positively correlated with AFDM (r2=0.23). Ecosystem metabolism displayed a strong seasonality, with GPP averaging 4.5 and 8.4 and ER averaging 5.4 and 9.9 g O2 m-2 d-1 for the two sites, respectively, thus indicating a predominance of heterotrophy (P:R<1) in these high-elevation, open-canopied systems. Bacteria play a strong role in the trophic dynamics of alpine streams.
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| 5. |
- Schepens, Marloes A. A., et al.
(författare)
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Dietary calcium decreases but short-chain fructo-oligosaccharides increase colonic permeability in rats
- 2010
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Ingår i: British Journal of Nutrition. - Cambridge, United Kingdom : Cambridge University Press. - 0007-1145 .- 1475-2662. ; 104:12, s. 1780-1786
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Tidskriftsartikel (refereegranskat)abstract
- An increased intestinal permeability is associated with several diseases. Nutrition can influence gut permeability. Previously, we showed that dietary Ca decreases whereas dietary short-chain fructo-oligosaccharides (scFOS) increase intestinal permeability in rats. However, it is unknown how and where in the gastrointestinal tract Ca and scFOS exert their effects. Rats were fed a Western low-Ca control diet, or a similar diet supplemented with either Ca or scFOS. Lactulose plus mannitol and Cr-EDTA were added to the diets to quantify small and total gastrointestinal permeability, respectively. Additionally, colonic tissue was mounted in Ussing chambers and exposed to faecal water of these rats. Dietary Ca immediately decreased urinary Cr-EDTA excretion by 24 % in Ca-fed rats compared with control rats. Dietary scFOS increased total Cr-EDTA permeability gradually with time, likely reflecting relatively slow gut microbiota adaptations, which finally resulted in a 30 % increase. The lactulose: mannitol ratio was 15 % higher for Ca-fed rats and 16 % lower for scFOS-fed rats compared with control rats. However, no dietary effect was present on individual urinary lactulose and mannitol excretion. The faecal waters did not influence colonic permeability in Ussing chambers. In conclusion, despite effects on the lactulose: mannitol ratio, individual lactulose values did not alter, indicating that diet did not influence small-intestinal permeability. Therefore, both nutrients affect permeability only in the colon: Ca decreases, while scFOS increase colonic permeability. As faecal water did not influence permeability in Ussing chambers, probably modulation of mucins and/or microbiota is important for the in vivo effects of dietary Ca and scFOS.
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| 6. |
- Schepens, Marloes A. A., et al.
(författare)
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Supplemental antioxidants do not ameliorate colitis development in HLA-B27 transgenic rats despite extremely low glutathione levels in colonic mucosa
- 2011
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Ingår i: Inflammatory Bowel Diseases. - : Oxford University Press (OUP). - 1078-0998 .- 1536-4844. ; 17:10, s. 2065-2075
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Tidskriftsartikel (refereegranskat)abstract
- Background: Oxidative stress is presumed to play an important role in inflammatory bowel disease (IBD). Accordingly, antioxidant supplementation might be protective. Dietary calcium inhibited colitis development in HLA-B27 transgenic rats, an animal model mimicking IBD. As antioxidants might act at mucosa level and calcium predominantly in the gut lumen, we hypothesize that the combination has additive protective effects on colitis development. Methods: HLA-B27 rats were fed a control diet or the same diet supplemented with the antioxidants glutathione, vitamin C, and vitamin E, or supplemented with both antioxidants and calcium. Oxidative stress in colonic mucosa, colonic inflammation, intestinal permeability, and diarrhea were quantified. Results: Intestinal permeability, diarrhea, myeloperoxidase, and interleukin-1 beta levels were significantly lower in rats fed both antioxidants and calcium compared to rats supplemented with antioxidants only. No beneficial effects were observed in rats fed the diet supplemented with antioxidants only. Strikingly, despite extremely low colonic mucosal glutathione levels in HLA-B27 rats, there was no oxidative stress-related damage. Subsequent analyses showed no defect in expression of glutathione synthesis genes. Additional experiments, comparing young and older HLA-B27 rats, showed that glutathione levels and also reactive oxygen species production decreased with progression of intestinal inflammation. Conclusions: Antioxidant supplementation was ineffective in HLA-B27 rats despite low mucosal glutathione levels, because colitis development did not coincide with oxidative stress in this model. This indicates that the neutrophilic respiratory burst, and thus innate immune defense, is compromised in HLA-B27 rats. As supplementation with both calcium and antioxidants attenuated colitis development, we speculate that this protective effect is attributed to calcium only.
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| 7. |
- Schepens, Marloes A. A., et al.
(författare)
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The protective effect of supplemental calcium on colonic permeability depends on a calcium phosphate-induced increase in luminal buffering capacity
- 2012
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Ingår i: British Journal of Nutrition. - Cambridge, United Kingdom : Cambridge University Press. - 0007-1145 .- 1475-2662. ; 107:7, s. 950-956
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Tidskriftsartikel (refereegranskat)abstract
- An increased intestinal permeability is associated with several diseases. Previously, we have shown that dietary Ca decreases colonic permeability in rats. This might be explained by a calcium-phosphate-induced increase in luminal buffering capacity, which protects against an acidic pH due to microbial fermentation. Therefore, we investigated whether dietary phosphate is a co-player in the effect of Ca on permeability. Rats were fed a humanised low-Ca diet, or a similar diet supplemented with Ca and containing either high, medium or low phosphate concentrations. Chromium-EDTA was added as an inert dietary intestinal permeability marker. After dietary adaptation, short-chain fructo-oligosaccharides (scFOS) were added to all diets to stimulate fermentation, acidify the colonic contents and induce an increase in permeability. Dietary Ca prevented the scFOS-induced increase in intestinal permeability in rats fed medium- and high-phosphate diets but not in those fed the low-phosphate diet. This was associated with higher faecal water cytotoxicity and higher caecal lactate levels in the latter group. Moreover, food intake and body weight during scFOS supplementation were adversely affected by the low-phosphate diet. Importantly, luminal buffering capacity was higher in rats fed the medium- and high-phosphate diets compared with those fed the low-phosphate diet. The protective effect of dietary Ca on intestinal permeability is impaired if dietary phosphate is low. This is associated with a calcium phosphate-induced increase in luminal buffering capacity. Dragging phosphate into the colon and thereby increasing the colonic phosphate concentration is at least part of the mechanism behind the protective effect of Ca on intestinal permeability.
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| 8. |
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