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Artificial nutrition modifies gut associated lymphoid tissue (GALT) in rat
ESPEN Research Fellows Symposium 15th Congress of the European Society of Parenteral and Enteral Nutrition, September 1993. Artificial nutrition modifies gut associated lymphoid tissue (GALT) in rat V. Merle, V. Colomb, Y. Cbourrout, M. Leborgne, 0. Corriol, E. Lerebours, C. Ricour and N. Brousse, Hbpital Nechw. 7574.3 Puris. France.
Introduction The gut associated lymphoid tissue (GALT) is in close contact with dietary antigens, but how these dietary antigens can influence intestinal immunity is unknown. The removal of dietary antigens can be achieved by artificial nutrition (total parenteral nutrition as well as an enteral elemental diet), which provides a good model for studying the effects of intraluminal dietary antigens on GALT. Some authors (1,2) have investigated the effects of total parenteral nutrition (TPN) on intestinal immunity in rat. but their results are questionable because of methodological difficulties. especially the lack of lipids in the nutritive solution. We decided to investigate the effects of a lipid containing nutritive solution administered either parenterally or enterally on intestinal immunity in rat. Methods 4 groups of 18 male Wistar rats were studied as follows: Group 1: total parenteral nutrition (TPN) administered through a catheter placed in the vena cava: Group 2: sham-operated rats, with a catheter in the vena cava but receiving an oral diet (compared to the rats of group 1) Group 3: elemental enteral diet (EED), administered through a catheter placed in the stomach; Group 4: sham-operated rats receiving an oral diet (compared to the rats of group 3). The rats were sacrificed after 2,7 or 14 days of nutrition. The artifical nutrition began 6 + 1 days after catheterisation. Rats with a jugular catheter were randomly assigned to either group 1 or group 2. Rats in group 1 were fed the nutritive solution (300 ml/kg/day, 260 kcal/kg/day. 1.92 g of nitrogen/kg/day, 136 calorie to nitrogen ratio) and received no food orally. Rats in group 2 received NaCI 0.9% (2 ml/h) to maintain the catheter patency but were fed orally till the end of the study. Rats with gastrostomy (group 3) were fed through the gastric catheter with the same solution as those in group 1 and received no food orally. Rats with laparotomy but no gastric catheter (group 4) were allowed to continue oral nutrition until the end of the study. Energy intake (kcal/kg/day) and calorie to nitrogen ratio were nearly identical in the 4 groups of rats. The rats were sacrificed after 2.7 or 14 days of artificial nutrition. The entire small bowel was removed immediately. One segment of duodenum and one segment of jejenum were studied by immunochemistry with monoclonal antibodies (mAB) directed against CD4, CD5. CD8, CD25 antigens, against macrophages and against class II major histocompatibility complex antigen (MHC II). The villus to crypt ratio of the intestinal mucosa was measured in each segment after hematoxylin-eosin staining.
Budapest, 12-15
Numbers of stained cells at the same site were compared between the different groups of rats using the Mann-Whitney test for unpaired data. The same test was used to compare the villus to crypt ratios between the different groups. For MHC II staining. the number of rats with normal staining was compared between the different groups using a Chi-square test. Results The mean daily growth expressed as daily weight gain as a fraction of weight at the beginning of the study was not statistically different between the 4 groups at days 7 and 14. The villus to crypt ratio in the duodenum was smaller in group I than in the controls (group 2) after 7 days of artificial nutrition (2.7 k 0.29 vs 3.02 f 0.23. p < 0.05) and after 14 days (2.7 f 0.15 vs 3.5 * 0.49, p < 0.05). There was no statistical difference in the villus to crypt ratio in the jejunum. The villus to crypt ratio in both the duodenum and the jejunum was not statistically different between the rats of the group 3 and their controls (group 4) at days 2.7 and 14.
I. Enteral nutrition - The expression of MHC I1 on the epithelium of the villi disappeared in the duodenum by day 2 after the beginning of enteral nutrition. In the jejunum. the decrease in the expression of MHC II on the epithelium of the villi in the rats of group 3 did not reach significance. CD5+. CD4+ and CD8+ cells were decreased in the epitbelium of both the duodenum and the jejunum. This decrease became significant at day 2 after the onset of enteral nutrition in the duodenum for CD5+ and CD8+ cells. No change was observed in the lamina propria. No change was observed in the number of CD25 lymphocytes and in the number of macrophages during enteral nutrition. 2. Parenteral nutrition - There was no significant difference in the epithelial expression of MHC II between group I and 2. The number of CDR+ cells increased significatively (p < 0.05) after 14 days of parenteral nutrition, both in the epithelium and in the lamina propria. This increase was seen in both the duodenum and the jejunum. No change was observed in the number of CD4+, CD5+, CD25+ and macrophages, either in the iamina propria or in the epithelium. Conclusion In conclusion. our study demonstrates an effect of artificial nutrition on intestinal immunity. The effects of enteral and parenteral nutrition are different. and they occur earlier during enteral nutrition. The mechanisms through which these changes occur are still to be investigated. References Tanaka S. Miura S. Tashiro H et al. Morphologtcal alteration ofgutassociated lymphoid tissue after long-term total parenteral nutrition. Cell Tissue Res 1991: 226: 29-36. Alverdy J A, Aoys E, Weiss-Canington P. Burke D A. The effect of glutamine-enriched TPN on gut immune cellularity. J Surg Res 1992: 52: 34-38.
Introduction The gut associated lymphoid tissue (GALT) is in close contact with dietary antigens, but how these dietary antigens can influence intestinal immunity is unknown. The removal of dietary antigens can be achieved by artificial nutrition (total parenteral nutrition as well as an enteral elemental diet), which provides a good model for studying the effects of intraluminal dietary antigens on GALT. Some authors (1,2) have investigated the effects of total parenteral nutrition (TPN) on intestinal immunity in rat. but their results are questionable because of methodological difficulties. especially the lack of lipids in the nutritive solution. We decided to investigate the effects of a lipid containing nutritive solution administered either parenterally or enterally on intestinal immunity in rat. Methods 4 groups of 18 male Wistar rats were studied as follows: Group 1: total parenteral nutrition (TPN) administered through a catheter placed in the vena cava: Group 2: sham-operated rats, with a catheter in the vena cava but receiving an oral diet (compared to the rats of group 1) Group 3: elemental enteral diet (EED), administered through a catheter placed in the stomach; Group 4: sham-operated rats receiving an oral diet (compared to the rats of group 3). The rats were sacrificed after 2,7 or 14 days of nutrition. The artifical nutrition began 6 + 1 days after catheterisation. Rats with a jugular catheter were randomly assigned to either group 1 or group 2. Rats in group 1 were fed the nutritive solution (300 ml/kg/day, 260 kcal/kg/day. 1.92 g of nitrogen/kg/day, 136 calorie to nitrogen ratio) and received no food orally. Rats in group 2 received NaCI 0.9% (2 ml/h) to maintain the catheter patency but were fed orally till the end of the study. Rats with gastrostomy (group 3) were fed through the gastric catheter with the same solution as those in group 1 and received no food orally. Rats with laparotomy but no gastric catheter (group 4) were allowed to continue oral nutrition until the end of the study. Energy intake (kcal/kg/day) and calorie to nitrogen ratio were nearly identical in the 4 groups of rats. The rats were sacrificed after 2.7 or 14 days of artificial nutrition. The entire small bowel was removed immediately. One segment of duodenum and one segment of jejenum were studied by immunochemistry with monoclonal antibodies (mAB) directed against CD4, CD5. CD8, CD25 antigens, against macrophages and against class II major histocompatibility complex antigen (MHC II). The villus to crypt ratio of the intestinal mucosa was measured in each segment after hematoxylin-eosin staining.
Budapest, 12-15
Numbers of stained cells at the same site were compared between the different groups of rats using the Mann-Whitney test for unpaired data. The same test was used to compare the villus to crypt ratios between the different groups. For MHC II staining. the number of rats with normal staining was compared between the different groups using a Chi-square test. Results The mean daily growth expressed as daily weight gain as a fraction of weight at the beginning of the study was not statistically different between the 4 groups at days 7 and 14. The villus to crypt ratio in the duodenum was smaller in group I than in the controls (group 2) after 7 days of artificial nutrition (2.7 k 0.29 vs 3.02 f 0.23. p < 0.05) and after 14 days (2.7 f 0.15 vs 3.5 * 0.49, p < 0.05). There was no statistical difference in the villus to crypt ratio in the jejunum. The villus to crypt ratio in both the duodenum and the jejunum was not statistically different between the rats of the group 3 and their controls (group 4) at days 2.7 and 14.
I. Enteral nutrition - The expression of MHC I1 on the epithelium of the villi disappeared in the duodenum by day 2 after the beginning of enteral nutrition. In the jejunum. the decrease in the expression of MHC II on the epithelium of the villi in the rats of group 3 did not reach significance. CD5+. CD4+ and CD8+ cells were decreased in the epitbelium of both the duodenum and the jejunum. This decrease became significant at day 2 after the onset of enteral nutrition in the duodenum for CD5+ and CD8+ cells. No change was observed in the lamina propria. No change was observed in the number of CD25 lymphocytes and in the number of macrophages during enteral nutrition. 2. Parenteral nutrition - There was no significant difference in the epithelial expression of MHC II between group I and 2. The number of CDR+ cells increased significatively (p < 0.05) after 14 days of parenteral nutrition, both in the epithelium and in the lamina propria. This increase was seen in both the duodenum and the jejunum. No change was observed in the number of CD4+, CD5+, CD25+ and macrophages, either in the iamina propria or in the epithelium. Conclusion In conclusion. our study demonstrates an effect of artificial nutrition on intestinal immunity. The effects of enteral and parenteral nutrition are different. and they occur earlier during enteral nutrition. The mechanisms through which these changes occur are still to be investigated. References Tanaka S. Miura S. Tashiro H et al. Morphologtcal alteration ofgutassociated lymphoid tissue after long-term total parenteral nutrition. Cell Tissue Res 1991: 226: 29-36. Alverdy J A, Aoys E, Weiss-Canington P. Burke D A. The effect of glutamine-enriched TPN on gut immune cellularity. J Surg Res 1992: 52: 34-38.