T lymphocyte numbers in human gut associated lymphoid tissue are reduced without enteral nutrition

Meeting Calorie and Protein Needs in the Critical Care Unit: A Prospective Observational Pilot Study

Background:

Inadequate calorie and protein intake during critical illness is associated with poor clinical outcomes. Unfortunately, most critically ill patients do not consume adequate levels of these nutrients. An enteral formula with appropriate macronutrient composition may assist patients in meeting nutritional goals.

Design:

This study was a single center, prospective, observational study of 29 adults in the medical intensive care unit who required enteral nutrition for at least 3 days. Subjects received a calorically dense, enzymatically hydrolyzed 100% whey peptide-based enteral formula for up to 5 days to assess the ability to achieve 50% of caloric goals within the first 3 days (primary outcome), the daily percentage of protein goals attained and gastrointestinal tolerance (secondary outcomes).

Result:

A total of 29 subjects consented and began the study. Four subjects dropped out before first day and 25 subjects were included in analyses. Subjects were aged 55.5 ± 16.9 years with mean body mass index (BMI) of 27.9 ± 7.5 kg/m². Most (92%) subjects were on a mechanical ventilator and experienced organ failure. At least 50% of caloric and protein goals were achieved in 78.9% and 73.7% of the subjects, respectively, during the first 3 days. Overall, 75.0 ± 26.3% and 69.3 ± 26.7% of calorie and protein goals were achieved using the study formula.

Conclusions:

Subjects fed enterally with a calorically dense, enzymatically hydrolyzed 100% whey peptide-based enteral formula exceeded 50% of caloric and protein goals in most critically ill subjects included in this study. Use of study formula did not lead to severe gastrointestinal intolerance.

Interleukin-7 Dose-Dependently Restores Parenteral Nutrition–Induced Gut-Associated Lymphoid Tissue Cell Loss but Does Not Improve Intestinal Immunoglobulin A Levels

BACKGROUND

Without enteral nutrition, the mass and function of gut-associated lymphoid tissue (GALT), a center of systemic mucosal immunity, are reduced. Therefore, new therapeutic methods, designed to preserve mucosal immunity during parenteral nutrition (PN), are needed. Our recent study revealed that exogenous interleukin-7 (IL-7; 1 microg/kg twice a day) restores the GALT cell mass lost during intravenous (IV) PN but does not improve secretory immunoglobulin A (IgA) levels. Herein, we studied the IL-7 dose response to determine the optimal IL-7 dose for recovery of GALT mass and function during IV PN. We hypothesized that a high dose of IL-7 would increase intestinal IgA levels, as well as GALT cell numbers.

METHODS

Male mice (n = 42) were randomized to chow, IL-7-0, IL-7-0.1, IL-7-0.33, IL-7-1 and IL-7-3.3 groups and underwent jugular vein catheter insertion. The IL-7 groups were fed a standard PN solution and received IV injections of normal saline (IL-7-0), 0.1, 0.33, 1, or 3.3 microg/kg of IL-7 twice a day. The chow group was fed chow ad libitum. After 5 days of treatment, the entire small intestine was harvested and lymphocytes were isolated from Peyer's patches (PPs), intraepithelial (IE) spaces, and the lamina propria (LP). The lymphocytes were counted and phenotypes determined by flow cytometry (alphabetaTCR, gammadeltaTCR, CD4, CD8, B cell). IgA levels of small intestinal washings were also examined using ELISA (enzyme-linked immunoabsorbent assay).

RESULTS

IL-7 dose-dependently increased total lymphocyte numbers in PPs and the LP. The number of lymphocytes harvested from IE spaces reached a plateau at 1 microg/kg of IL-7. There were no significant differences in any phenotype percentages at any GALT sites among the groups. IgA levels of intestinal washings were significantly higher in the chow group than in any of the IL-7 groups, with similar levels in all IL-7 groups.

CONCLUSIONS

Exogenous IL-7 dose-dependently reverses PN-induced GALT cell loss, with no major changes in small intestinal IgA levels. IL-7 treatment during PN appears to have beneficial effects on gut immunity, but other therapeutic methods are needed to restore secretory IgA levels.

5-Fluorouracil Infusion Reduces Gut-Associated Lymphoid Tissue Cell Number and Mucosal Immunoglobulin A Levels

BACKGROUND

Anticancer drugs have been demonstrated to affect gut mucosal morphology and cause gastrointestinal symptoms. We hypothesized that even small doses of 5-fluorouracil (5-FU) would reduce gut-associated lymphoid tissue (GALT) mass and function.

METHODS

Mice underwent IV cannulation and received continuous infusion of normal saline or 10 mg/kg of 5-FU for 5 days. GALT cell numbers, phenotypes, and mucosal immunoglobulin A (IgA) levels were measured.

RESULTS

During the infusion, there were no significant differences in food intake or body weight change between the 2 groups. Cell yields from the intraepithelial space and lamina propria of the small intestine were lower in the 5-FU than the control group. The lamina propria CD4/CD8 ratio was reduced in the 5-FU compared with the control group. Intestinal and respiratory tract IgA levels were lower in the 5-FU than in the control group.

CONCLUSIONS

A small dose of 5-FU reduces GALT cell number and mucosal IgA levels, regardless of food intake.

Comparison of Two Different Enteral Nutrition Protocol in Critically Ill Patients

OBJECTIVE

In this study, two enteral nutrition protocols with different gastric residual volumes (GRVs) and different monitoring intervals were compared with respect to gastrointestinal intolerance findings in intensive care unit (ICU) patients.

METHODS

The study was carried out prospectively in 60 patients in the anaesthesiology and reanimation ICU under mechanical ventilation support, who were scheduled to take enteral feeding. Patients were sequentially divided into two groups: Group 1, GRV threshold of 100 mL, and monitoring interval of 4 hours, and Group 2, GRV threshold of 200 mL, monitoring interval of 8 hours. To test the significant difference between the groups, Student's t test, chi-square text and Fisher exact test were used.

RESULTS

In Group 1, 3.3% vomiting, 6.6% diarrhoea was observed; in Group 2, 16.6% vomiting, 10% diarrhoea. In terms of total intolerance (vomiting and/or diarrhoea) of the two groups, the incidence was significantly higher in Group 2 (33.3%) than in Group 1 (10%) (p=0.02).

CONCLUSION

According to the results of the study, a lower gastrointestinal intolerance rate was detected in the GRV threshold 100 mL, monitoring interval for 4 hours protocol (Group 1) than in GRV threshold 200 mL, monitoring interval for 8 hours protocol (Group 2); Group 1 may be preferred renovation.

Computed Tomography (CT) Scanning Facilitates Early Identification of Neonatal Cystic Fibrosis Piglets

Background

Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. A cystic fibrosis transmembrane conductance regulator knockout (CFTR-/-) pig that displays most of the features of the human CF disease has been recently developed. However, CFTR^-/- pigs presents a 100% prevalence of meconium ileus that leads to death in the first hours after birth, requiring a rapid diagnosis and surgical intervention to relieve intestinal obstruction. Identification of CFTR^-/- piglets is usually performed by PCR genotyping, a procedure that lasts between 4 to 6 h. Here, we aimed to develop a procedure for rapid identification of CFTR^-/- piglets that will allow placing them under intensive care soon after birth and immediately proceeding with the surgical correction.

Methods and Principal Findings

Male and female CFTR^+/- pigs were crossed and the progeny was examined by computed tomography (CT) scan to detect the presence of meconium ileus and facilitate a rapid post-natal surgical intervention. Genotype was confirmed by PCR. CT scan presented a 94.4% sensitivity to diagnose CFTR^-/- piglets. Diagnosis by CT scan reduced the birth-to-surgery time from a minimum of 10 h down to a minimum of 2.5 h and increased the survival of CFTR^-/- piglets to a maximum of 13 days post-surgery as opposed to just 66 h after later surgery.

Conclusion

CT scan imaging of meconium ileus is an accurate method for rapid identification of CFTR^-/- piglets. Early CT detection of meconium ileus may help to extend the lifespan of CFTR^-/- piglets and, thus, improve experimental research on CF, still an incurable disease.

Lack of preoperative enteral nutrition reduces gut-associated lymphoid cell numbers in colon cancer patients: a possible mechanism underlying increased postoperative infectious complications during parenteral nutrition

OBJECTIVE

To examine preoperative dietary influences on gut-associated lymphoid tissue (GALT) cell number in the context of postoperative infectious complications.

BACKGROUND

There is little clinical evidence regarding whether nutritional routes affect GALT size and/or phenotype. The influence of GALT atrophy on clinical outcomes is also unclear.

METHOD

Patients with complete obstruction of the colon due to a tumor were excluded from this study. Study 1. Resected terminal ileum specimens, from 62 patients [preoperative parenteral nutrition (PN): n = 15, preoperative oral feeding (OF): n = 47] who underwent right colectomy during the period from 1997 to 2004 at our department, were immunohistochemically stained for counting numbers of T, IgA-producing, and mature and immature dendritic cells (DCs) in the lamina propria (LP) and intraepithelial space.Study 2. We reviewed 341 patients (PN: n = 99, OF: n = 242) with colon cancer who underwent colectomy during this period for postoperative complications.

RESULTS

Study 1. T cell numbers in the LP and intraepithelial space and IgA-producing cell number in the LP were significantly lower in the PN than in the OF group. Mature DC number in the LP was significantly lower in the PN than in the OF group, whereas total DC numbers (both mature and immature DC) were similar in the 2 groups.Study 2. The PN group had significantly higher rates of total infectious complications, surgical site infection, pneumonia, infectious colitis, and central venous catheter infection.

CONCLUSIONS

Lack of enteral delivery of nutrients reduces numbers of T and IgA-producing cells, as well as mature DCs, in GALT of colon cancer patients, as it does in animal models. A close association between GALT changes and infectious complication morbidity was confirmed.

The new prophylactic strategy for colon cancer in inflammatory bowel disease by modulating microbiota

It is well understood that intestinal microbiota play an important role in the pathogenesis of inflammatory bowel disease (IBD). In addition, IBD patients are well known to have a higher risk of developing colon cancer due to chronic inflammation. Recent evidence suggests that manipulation of microbiota improves the clinical outcome of patients with IBD and may reduce onset of colon cancer without obvious toxicity. This review summarizes the current experimental and clinical knowledge about the role of intestinal microbiota in IBD and colon cancer, and the nutraceutical therapy for colon cancer.

Neutrophil elastase inhibitor restores gut ischemia reperfusion-induced impairment of gut immunity with reduced plasma interleukin-6 concentrations in mice

BACKGROUND AND PURPOSE

Gut-associated lymphoid tissue (GALT) is regarded as central mucosa-associated lymphoid tissue that influences systemic mucosal immunity. Our previous study revealed that gut ischemia and reperfusion (I/R) reduces GALT lymphocyte numbers. Because gut hypoperfusion frequently occurs in trauma, shock, and surgery patients, establishment of a therapeutic method to preserve GALT mass after gut I/R may be important for the prevention of infections. We examined the effects of sivelestat sodium hydrate, a selective inhibitor of neutrophil elastase, on GALT mass and plasma cytokine concentrations in a murine gut I/R model.

METHODS

Seventy male ICR mice were randomized to the control (n = 34) or the sivelestat (n = 36) group. After intravenous cannulation of the animals, the superior mesenteric artery was occluded for 60 min. After reperfusion, physiologic saline or sivelestat 5 mg/kg hourly was infused for 24 h. Sixteen mice in the control and 22 in the sivelestat group were alive at 24 h. Twenty-six mice (n = 13 in each group) were chosen randomly for harvest of the small intestine. Lymphocytes from Peyer patches (PP), the intraepithelial space (IE), and the lamina propria (LP) were counted; and their phenotypes (αβT-cell receptor (TCR), γδTCR, CD4, CD8, B cell) were determined by flow cytometry. Cytokine concentrations (interleukin [IL]-6, IL-1β, IL-10) in the plasma and bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay.

RESULTS

Sivelestat treatment did not improve survival but increased PP and IE lymphocyte numbers significantly and reduced the LP CD8(+) cell percentage and plasma IL-6 concentration compared with controls. There were no significant differences between the two groups in other cell phenotypes or cytokine concentrations.

CONCLUSION

Sivelestat treatment after gut I/R may be useful for maintaining gut immunity and preventing systemic inflammatory responses.

Oral administration of Alequel, a mixture of autologous colon-extracted proteins for the treatment of Crohn's disease

The pathogenesis of Crohn's disease involves an immune-mediated damage to the gut mucosa. Current developed therapies are based on the use of immunosuppressive drugs that can lead to significant drug-related adverse responses. There is a need for a therapeutic strategy that is more specific and less global in its effect on the immune system. Oral tolerance is an active process wherein oral administration of antigens is associated with the induction of regulatory cells and the suppression of effector cells directed toward specific and nonspecific antigens. Studies in animal models of experimental colitis suggest that oral administration of proteins extracted from the gut can induce tolerance and alleviate the disease symptoms. Recent clinical trials showed that oral administration of Alequel, an autologous protein-containing colon extract, to patients with Crohn's disease is safe and may be effective as a therapeutic modality for treating the disease. This treatment was associated with disease-associated antigen alterations of the immune response in the patients. Oral administration of Alequel could provide a patient-tailored approach that is side-effect-free for the treatment of patients with Crohn's disease.

Dietary modulation of inflammation-induced colorectal cancer through PPARγ

Mounting evidence suggests that the risk of developing colorectal cancer (CRC) is dramatically increased for patients with chronic inflammatory diseases. For instance, patients with Crohn's Disease (CD) or Ulcerative Colitis (UC) have a 12-20% increased risk for developing CRC. Preventive strategies utilizing nontoxic natural compounds that modulate immune responses could be successful in the suppression of inflammation-driven colorectal cancer in high-risk groups. The increase of peroxisome proliferator-activated receptor-γ (PPAR-γ) expression and its transcriptional activity has been identified as a target for anti-inflammatory efforts, and the suppression of inflammation-driven colon cancer. PPARγ down-modulates inflammation and elicits antiproliferative and proapoptotic actions in epithelial cells. All of which may decrease the risk for inflammation-induced CRC. This review will focus on the use of orally active, naturally occurring chemopreventive approaches against inflammation-induced CRC that target PPARγ and therefore down-modulate inflammation.

Food fight! Parenteral nutrition, enteral stimulation and gut-derived mucosal immunity

INTRODUCTION

Nutrition support is an integral component of modern patient care. Type and route of nutritional support impacts clinical infectious outcomes in critically injured patients.

DISCUSSION

This article reviews the relationships between type and route of nutrition and gut-derived mucosal immunity in both the clinical and laboratory settings.

Reversal of parenteral nutrition-induced gut mucosal immunity impairment with small amounts of a complex enteral diet

BACKGROUND

Although parenteral nutrition (PN) prevents progressive malnutrition, lack of enteral nutrition (EN) during PN leads to gut associated lymphoid tissue (GALT) atrophy and dysfunction. Administering a small amount of EN with PN reportedly prevents increases in intestinal permeability. However, its effects on GALT remain unclear. We analyzed the minimum amount of EN required to preserve gut immunity during PN.

METHODS

Male Institute of Cancer Research mice underwent jugular vein catheter insertion and tube gastrostomy. They were randomized into four groups to receive isocaloric and isonitrogenous nutritional support with variable EN to PN ratios (EN 0, EN 33, EN 66, and EN 100). EN was provided with a complex enteral diet. After 5 days of feeding, the mice were killed and whole small intestines were harvested. GALT lymphocytes were isolated and counted. Their phenotypes were analyzed by flow cytometry. IgA levels of small intestinal washings were analyzed with enzyme-linked immunosorbent assay.

RESULTS

Body weight changes did not differ between any two of the groups. Peyer's patch lymphocyte numbers increased in proportion to EN amount, whereas lamina propria lymphocyte numbers were significantly higher in the EN 100 than in the EN 0 group, with no marked increases in the EN 33 and EN 66 groups. Small intestinal IgA levels increased EN amount-dependently and reached a plateau at EN 66.

CONCLUSIONS

A small amount of EN partially reverses PN-induced GALT changes, suggesting beneficial but limited effects on gut mucosal immunity.

Influence of adding fish oil to parenteral nutrition on gut-associated lymphoid tissue

BACKGROUND

Lack of enteral nutrition reduces gut-associated lymphoid tissue (GALT) mass and function, a mechanism underlying the increased morbidity of infectious complications in severely injured or critically ill patients. Strategies to restore parenteral nutrition (PN)-induced changes of GALT mass and function have been pursued. However, the influences of adding fish oil to PN on gut immunity remain to be clarified.

METHODS

Male Institute of Cancer Research (ICR) mice (n = 50) were randomized to 4 groups: ad libitum chow (chow), fat free PN (fat (-)-PN), PN + fish oil (FO-PN), and PN + safflower oil (SO-PN). The PN groups were given isocaloric and isonitrogenous PN solutions. The FO- and SO-PN groups received 20% of total calories from fat emulsions. After 5 days of feeding, lymphocytes from Peyer's patches (PPs), the intraepithelial space (IE), and the lamina propria (LP) of the entire small intestine were isolated. GALT lymphocyte numbers and phenotypes (CD4+, CD8+, alphabetaTCR+, gammadeltaTCR+, B220+ cells) were determined. Immunoglobulin A (IgA) levels of small intestinal washings were also measured by enzyme-linked immunosorbent assay. Another set of mice (n = 24) was used to determine plasma fatty acid compositions after feeding.

RESULTS

Lymphocyte numbers from PPs and the LP and intestinal IgA levels were significantly lower in the PN groups than in the chow group, with no significant differences between any 2 PN groups. The FO- and SO-PN groups showed moderate recovery of IE cell numbers compared with the fat (-)-PN group. Omega-3 and omega-6 fatty acid levels were increased with fish and safflower oil additions, respectively, compared with the fat (-)-PN group.

CONCLUSIONS

Adding fish oil to PN does not exacerbate PN-induced GALT changes but rather partially reverses these changes, with increased plasma omega-3 fatty acid levels.

Is there evidence that the gut contributes to mucosal immunity in humans?

BACKGROUND

Our understanding of the common mucosal immune system derives from animal studies. Antigen-sensitized lymphocytes in the gut-associated lymphoid tissue (GALT) migrate via the blood to mucosal tissues to generate the mucosal-associated lymphoid tissue (MALT). In these sites, B cells differentiate into plasma cells and produce antigen-specific secretory IgA, the principal specific immune antiviral and antibacterial defense of moist mucosal surfaces. Responses to oral intake seem necessary to actively maintain this system in health. Experimentally, lack of enteral stimulation with parenteral feeding alters GALT and MALT size and function. These alterations disturb intestinal and extraintestinal mucosal immunity.

METHODS

This review is an overview of current and classical studies demonstrating the human mucosal immune system and interactions with nutrition.

RESULTS

Human evidence of the mucosal immune system exists, although most data are indirect. Gut stimulation after oral intake induces a generalized immune response in the human MALT through a mucosal-immune network. Examples include neonatal development of GALT influenced by enteral feeding, the presence of antigen-specific IgA and antigen-specific IgA-secreting plasma cells in distant mucosal effector sites such as the breast after gut luminal antigen exposure, and isolation of IgA-producing cells from circulating blood.

CONCLUSIONS

It is unlikely that clinical studies will ever completely define the effect of route of feeding in all patient populations. This may be possible, however, if investigators understand, define and characterize nutrition-dependent immunologic mechanisms, allowing clinicians to examine clinical responses to nutrition in specific patient populations. This might allow generation of new approaches to protect mucosal immunity.

Effects of probiotics and enteral and parenteral nutrition on intestinal mucosal addressin cell adhesion molecule-1 and immune barrier of rats with severe acute pancreatitis

AIM: To investigate the effects of probiotics and enteral and parenteral nutrition (EN and PN) on peyer's patch, intestinal mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and immune barrier of rats with severe acute pancreatitis (SAP).

METHODS: SAP model was established in 30 Sprague Dawley (SD) rats via biliary and pancreatic duct using sodium taurocholate and then were averagely divided into 3 groups: PN group, PN + EN group, and PN + EN + probiotics group. Twenty-four hours after modeling, the rats in each group were treated with the corresponding methods for 6 days. The nutrition support in the 3 groups was isonitrogenic and isocaloric. At the 7th day, all the rats were sacrificed. The expression of CD4, CD8, MadCAM-1 and IgA in the terminal ileum mucosa and peyer's patch were measured by immunohistochemistry. Vena cava blood and homogenated tissues of liver, lung and mesenteric lymph nodes were cultured to determine bacterial translocations.

RESULTS: The levels of CD4 and CD8 T cells, and the expression of MadCAM-1 and IgA in the terminal ileum mucosa and peyer's node were significantly higher in PN + EN and PN + EN + probiotics group than those in PN group (P < 0.05). The level of CD8 T cells and the expression of MadCAM-1 were markedly higher in PN + EN + probiotics group than those in PN + EN group (P < 0.05). Bacterial translocations and mortality appeared in PN group with higher rates (70.2%, 75.6%) in comparison with those in PN + EN + probiotics (27.5%, 50.0%) and PN + EN group (30.5%, 52.4%)(P < 0.01 or P < 0.05). But there were no significant differences between PN + EN and PN + EN + probiotics group.

CONCLUSION: EN can increase the expression of CD4, CD8, MadCAM-1 and IgA in the terminal ileum mucosa and peyer's patch, reduce bacterial translocations, and improve the survival rate in SAP. This effect becomes more obvious when EN is combined with probiotics. Probiotics seem to have litter effect in the protection of intestinal immune barrier.

EXOGENOUS INTERLEUKIN 7 AFFECTS GUT-ASSOCIATED LYMPHOID TISSUE IN MICE RECEIVING TOTAL PARENTERAL NUTRITION

In the absence of enteral nutrient delivery, gut-associated lymphoid tissue (GALT) mass and function are reduced. The purpose of this study was to examine whether exogenous interleukin (IL)-7 treatment reverses intravenous (IV)-total parenteral nutrition (TPN)-induced changes in GALT, immunoglobulin (Ig) A levels, and gut barrier function. Eighty-nine mice were randomized to chow, TPN, or TPN + IL-7 (1 microg/kg, administered IV twice a day) and treated for 5 days. The entire small intestine was harvested and lymphocytes were isolated from Peyer's patches (PPs), intraepithelial (IE) spaces, and the lamina propria (LP). Small intestinal and bronchoalveolar IgA levels were measured. Proximal and distal small intestinal levels of IgA-stimulating (IL-10) and IgA-inhibiting (IFNgamma) cytokines were determined with enzyme-linked immunoabsorbant assay. Moreover, 1 x 10 live Pseudomonas aeruginosa were delivered by gavage and survival was observed. TPN decreased total cell yields from PPs, IE spaces, and the LP compared with the chow group. IL-7 treatment restored cell numbers. PP CD4+, PP CD8+, IE gammadeltaTCR+, and LP CD4+ cell numbers were higher in the TPN + IL-7 group than in the TPN group. Secretory IgA levels were lower in the TPN and TPN + IL-7 than in the chow group. In the distal small intestine, IFNgamma levels were similar in the three groups, whereas IL-10 levels were reduced in the TPN and TPN + IL-7 groups relative to the chow group. Survival times were reduced in the TPN compared with the chow group, but IL-7 treatment significantly improved survival. Thus, exogenous IL-7 does not improve secretory IgA levels, nor are there any remarkable effects on levels of gut IgA-mediating cytokines. However, IL-7 treatment during TPN reverses TPN-induced GALT atrophy and improves survival in a gut-derived sepsis model.