Cranberry Proanthocyanidins Improve the Gut Mucous Layer Morphology and Function in Mice Receiving Elemental Enteral Nutrition

Background: Lamina propria Th2 cytokines, interleukin (IL)‐4 and IL‐13, stimulate goblet cell (GC) proliferation and MUC2 production, which protect the intestinal mucosa. Elemental enteral nutrition (EEN) reduces tissue IL‐4 and impairs barrier function. Proanthocyanidins (PACs) stimulate oral mucin levels. We hypothesized that adding PAC to EEN would maintain Th2–without stimulating Th1–cytokines and preserve luminal MUC2 vs EEN alone. Materials and Methods: Seventy mice were randomized to 5 diet groups–standard chow, intragastric EEN, or EEN with lowPAC, midPAC (50 mg), or highPAC (100 mg PAC/kg BW)–for 5 days, starting 2 days after gastric cannulation. Ileal tissue was analyzed for histomorphology and the cytokines IL‐4, IL‐13, IL‐1β, IL‐6, and TNF‐α by enzyme‐linked immunosorbent assay. MUC2 was measured in intestinal washes. Results: EEN lowered IL‐13 (P < .05) compared with standard chow, whereas IL‐4 was not significant (P < .07). LowPAC and midPAC increased IL‐13 (P < .05), whereas highPAC increased both IL‐4 and IL‐13 (P < .05) compared with EEN. All EEN diets reduced (P < .05) crypt depth compared with the chow group. Compared with standard chow, GC numbers and luminal MUC2 were reduced with EEN (P < .05). These effects were attenuated (P < .05) with midPAC and highPAC. No changes were observed in tissue Th1 cytokines. Conclusions: Adding PACs to EEN reverses impaired intestinal barrier function following EEN by improving the gut mucous layer and function through increased GC size and number as well as levels of MUC2 and ileal IL‐4 and IL‐13.     

Route and type of nutrition and surgical stress influence secretory phospholipase A2 secretion of the murine small intestine

Background: The function of secretory phospholipase A2 (sPLA2) is site dependent. In tissue, sPLA2 regulates eicosanoid production; in circulation, sPLA2 primes neutrophils; and in the intestinal lumen, sPLA2 provides innate bactericidal immunity as a defensin‐related protein. Since parenteral nutrition (PN) primes leukocytes while suppressing intraluminal mucosal immunity, the authors hypothesized that (1) PN would diminish luminal sPLA2 activity but increase activity in intestinal tissue and serum and (2) stress would accentuate these changes. Methods: Mice received chow, a complex enteral diet (CED), intragastric PN (IG‐PN), or PN in experiment 1 and chow, chow+stress, PN, or PN+stress in experiment 2. Results: In experiment 1, luminal sPLA2 activity was greatest in chow and decreased in CED, IG‐PN, and PN, with PN lower than CED and IG‐PN. Compared to that after chow, serum sPLA2 activity dropped after CED, IG‐PN, and PN. Serum sPLA2 was higher in portal than systemic serum. In experiment 2, PN lowered luminal sPLA2 activity vs chow. Stress lowered luminal sPLA2 activity in chow, without change in PN. Following stress, luminal immunoglobulin A increased in chow but not PN. Serum sPLA2 activity increased in PN. Conclusions: PN attenuates sPLA2 activity in intestinal fluid, consistent with suppressed innate mucosal defense. Stress suppresses luminal fluid sPLA2 activity in chow but not the immunoglobulin A response; PN impairs both. Stress significantly elevates serum sPLA2 in PN‐fed mice, consistent with known increased neutrophil priming with PN. PN reduces innate bactericidal immunity of the gut but upregulates serum proinflammatory products poststress.     

Partial Enteral Nutrition Preserves Elements of Gut Barrier Function,Including Innate Immunity,Intestinal Alkaline Phosphatase (IAP) Level,and Intestinal Microbiota in Mice

Lack of enteral nutrition (EN) during parenteral nutrition (PN) leads to higher incidence of infection because of gut barrier dysfunction. However, the effects of partial EN on intestina linnate immunity, intestinal alkaline phosphatase (IAP) and microbiota remain unclear. The mice were randomized into six groups to receive either standard chow or isocaloric and isonitrogenous nutritional support with variable partial EN to PN ratios. Five days later, the mice were sacrificed and tissue samples were collected. Bacterial translocation, the levels of lysozyme, mucin 2 (MUC2), and IAP were analyzed. The composition of intestinal microbiota was analyzed by 16S rRNA pyrosequencing. Compared with chow, total parenteral nutrition (TPN) resulted in a dysfunctional mucosal barrier, as evidenced by increased bacterial translocation (p < 0.05), loss of lysozyme, MUC2, and IAP, and changes in the gut microbiota (p < 0.001). Administration of 20% EN supplemented with PN significantly increased the concentrations of lysozyme, MUC2, IAP, and the mRNA levels of lysozyme and MUC2 (p < 0.001). The percentages of Bacteroidetes and Tenericutes were significantly lower in the 20% EN group than in the TPN group (p < 0.001). These changes were accompanied by maintained barrier function in bacterial culture (p < 0.05). Supplementation of PN with 20% EN preserves gut barrier function, by way of maintaining innate immunity, IAP and intestinal microbiota.     

Parenteral Nutrition Decreases Paneth Cell Function and Intestinal Bactericidal Activity While Increasing Susceptibility to Bacterial Enteroinvasion

Introduction: Parenteral nutrition (PN) increases the risk of infection in patients with contraindication to enteral feeding. Paneth cells produce and secrete antimicrobial products that protect the mucosa from pathogens. Their loss is associated with increased host‐pathogen interactions, mucosal inflammation, and altered microbiome composition. Hypothesis: We hypothesized that PN reduces Paneth cell product expression, and these changes would reduce bactericidal properties of tissue secretions following cholinergic stimulation, increase mucosal enteroinvasion, and shift the intestinal microbiome. Method: Experiment 1: Male ICR mice were randomized to Chow (n = 8) or PN (n = 8). Ileum tissue was collected for Paneth cell antimicrobial expression using RT‐PCR, stimulated with a cholinergic agonist degranulate Paneth cells bactericidal activity, or used to assess bacterial enteroinvasion in EVISC. Experiment 2: Mice were randomized to Chow (n = 11) or PN (n = 8) and ileum washing was collected for 16s pyrosequencing analysis. Results: Compared to Chow, PN decreased tissue expression of REGIII‐g (p < 0.002), lysozyme (p < 0.002), and cryptdin‐4 (p < 0.03). At the phylum level, PN decreased total Firmicutes but increased total Bacteroidetes, and Proteobacteria. Functionally, secretions from PN tissue was less bactericidal (p < 0.03) and demonstrated increased susceptibility to enteroinvasion by E coli (p < 0.02). Conclusion: PN without enteral nutrition impairs innate mucosal immune function. Tissue expression of Paneth cell antimicrobial proteins decreases associated with compositional shifts to the microbiome, decreased bactericidal activity of mucosal secretions and greater susceptibility of to enteroinvasion by E coli. These changes may explain in‐part the increased risk of infection in parenterally fed patients.     

Innate Mucosal Immune System Response of BALB/c vs C57BL/6 Mice to Injury in the Setting of Enteral and Parenteral Feeding

Background: Outbred mice exhibit increased airway and intestinal immunoglobulin A (IgA) following injury when fed normal chow, consistent with humans. Parenteral nutrition (PN) eliminates IgA increases at both sites. Inbred mice are needed for detailed immunological studies; however, specific strains have not been evaluated for this purpose. BALB/c and C57BL/6 are common inbred mouse strains but demonstrate divergent immune responses to analogous stress. This study addressed which inbred mouse strain best replicates the outbred mouse and human immune response to injury. Methods: Intravenously cannulated mice received chow or PN for 5 days and then underwent sacrifice at 0 or 8 hours following controlled surgical injury (BALB/c: n = 16–21/group; C57BL/6: n = 12–15/group). Bronchoalveolar lavage (BAL) was analyzed by enzyme‐linked immunosorbent assay for IgA, tumor necrosis factor–α (TNF‐α), interleukin (IL)–1β, and IL‐6, while small intestinal wash fluid (SIWF) was analyzed for IgA. Results: No significant increase in BAL IgA occurred following injury in chow‐ or PN‐fed BALB/c mice (chow: P = .1; PN: P = .7) despite significant increases in BAL TNF‐α and SIWF IgA (chow: 264 ± 28 vs 548 ± 37, P < .0001; PN: 150 ± 12 vs 301 ± 17, P < .0001). Injury significantly increased mucosal IgA in chow‐fed C57BL/6 mice (BAL: 149 ± 33 vs 342 ± 87, P = .01; SIWF: 236 ± 28 vs 335 ± 32, P = .006) and BAL cytokines. After injury, PN‐fed C57BL/6 mice exhibited no difference in BAL IgA (P = .9), BAL cytokines, or SIWF IgA (P = .1). Conclusions: C57BL/6 mice exhibit similar airway responses to injury as outbred mice and humans, providing an appropriate model for studying mucosal responses to injury. The BALB/c mucosal immune system responds differently to injury and does not replicate the human injury response.     

Cranberry Proanthocyanidins Improve Intestinal sIgA During Elemental Enteral Nutrition

Background: Elemental enteral nutrition (EEN) decreases gut‐associated lymphoid tissue (GALT) function, including fewer Peyer's patch lymphocytes and lower levels of the tissue T helper 2 (Th2) cytokines and mucosal transport protein polymeric immunoglobulin receptor (pIgR), leading to lower luminal secretory immunoglobulin A (sIgA) levels. Since we recently demonstrated that cranberry proanthocyanidins (PACs) maintain the Th2 cytokine interleukin (IL)–4 when added to EEN, we hypothesized the addition of PACs to EEN would normalize other GALT parameters and maintain luminal levels of sIgA. Methods: Institute of Cancer Research mice were randomized (12/group) to receive chow, EEN, or EEN + PACs (100 mg/kg body weight) for 5 days, starting 2 days after intragastric cannulation. Ileum tissue was collected to measure IL‐4 by enzyme‐linked immunosorbent assay, pIgR by Western blot, and phosphorylated STAT‐6 by microarray. Intestinal wash fluid was collected to measure sIgA by Western blot. Results: Compared with chow, EEN significantly decreased tissue IL‐4, phosphorylated STAT‐6, and pIgR. The addition of PACs to EEN prevented these alterations. Compared with chow, EEN resulted in significantly lower levels of luminal sIgA. The addition of PACs to EEN increased luminal sIgA levels compared with EEN alone. Conclusions: This study suggests the addition of PACs to EEN may support GALT function and maintain intestinal sIgA levels compared with EEN administration alone.     

Effects of adding butyric acid to PN on gut-associated lymphoid tissue and mucosal immunoglobulin A levels

Background: Parenteral nutrition (PN) causes intestinal mucosal atrophy, gut‐associated lymphoid tissue (GALT) atrophy and dysfunction, leading to impaired mucosal immunity and increased susceptibility to infectious complications. Therefore, new PN formulations are needed to maintain mucosal immunity. Short‐chain fatty acids have been demonstrated to exert beneficial effects on the intestinal mucosa. We examined the effects of adding butyric acid to PN on GALT lymphocyte numbers, phenotypes, mucosal immunoglobulin A (IgA) levels, and intestinal morphology in mice. Methods: Male Institute of Cancer Research mice (n = 103) were randomized to receive either standard PN (S‐PN), butyric acid–supplemented PN (Bu‐PN), or ad libitum chow (control) groups. The mice were fed these respective diets for 5 days. In experiment 1, cells were isolated from Peyer's patches (PPs) to determine lymphocyte numbers and phenotypes (αβTCR⁺, γδTCR⁺, CD4⁺, CD8⁺, B220⁺ cells). IgA levels in small intestinal washings were also measured. In experiment 2, IgA levels in respiratory tract (bronchoalveolar and nasal) washings were measured. In experiment 3, small intestinal morphology was evaluated. Results: Lymphocyte yields from PPs and small intestinal, bronchoalveolar, and nasal washing IgA levels were all significantly lower in the S‐PN group than in the control group. Bu‐PN moderately, but significantly, restored PP lymphocyte numbers, as well as intestinal and bronchoalveolar IgA levels, as compared with S‐PN. Villous height and crypt depth in the small intestine were significantly decreased in the S‐PN group vs the control group, however Bu‐PN restored intestinal morphology. Conclusions: A new PN formula containing butyric acid is feasible and would ameliorate PN‐induced impairment of mucosal immunity.     

Parenteral Feeding Depletes Pulmonary Lymphocyte Populations

Background: The effect of parenteral nutrition (PN) on lymphocyte mass in the lung is unknown, but reduced mucosal lymphocytes are hypothesized to play a role in the reduced immunoglobulin A–mediated immunity in both gut and lung. The ability to transfer and track cells between mice may allow study of diet‐induced mucosal immune function. The objectives of this study are to characterize lung T‐cell populations following parenteral feeding and to study distribution patterns of transferred donor lung T cells in recipient mice. Methods: In experiment 1, cannulated male Balb/c mice are randomized to receive chow or PN for 5 days. Lung lymphocytes are obtained via collagenase digestion, and flow cytometric analysis is used to identify total T (CD3+) and B (CD45/B220+) cells. In experiment 2, isolated lung T cells from chow‐fed male Balb/c mice are pooled and labeled in vitro with a fluorescent dye (carboxyfluorescein diacetate succinimidyl ester [CFSE]), and 1.1 × 10⁸ CFSE+ cells (3.1 × 10⁶ T cells) are transferred to chow‐fed Balb/c recipients. Cells recovered from recipient lungs and intestinal lamina propria (LP) are analyzed by flow cytometry to determine CFSE/CD3+ T cells at 1, 2, and 7 days. In experiment 3, cells are transferred to PN‐fed recipients. Results: In experiment 1, PN significantly decreases lung T‐ and B‐cell populations compared with chow feeding. In experiment 2, CFSE+ T‐cell retention is highest on day 1 in lung and LP, and decreases on day 2. Cells are gone by day 7; 98.1% of retained donor lung T cells migrate to recipient lungs and 1.9% to the intestine on day 1. Similar results are seen in experiment 3 after transfer of cells to PN‐fed recipients. Conclusions: PN reduces pulmonary lymphocyte populations consistent with impaired respiratory immunity. Transferred lung T cells preferentially localize to recipient lungs rather than intestine with maximal accumulation at 24 hours. Limited cross‐talk of transferred lung T cells to the intestine indicates that mucosal lymphocyte traffic might be programmed to localize to specific effector sites.     

Lack of enteral nutrition delays nuclear factor kappa B activation in peritoneal exudative cells in a murine glycogen-induced peritonitis model

Background: Early enteral nutrition is associated with a lower incidence of intraabdominal abscess in severely injured patients than parenteral nutrition (PN). We explored the underlying mechanisms by examining the influence of nutrition route on nuclear factor κB (NFκB) activation in peritoneal exudative cells (PECs) and peritoneal cytokine levels. Methods: Thirty male Institute Cancer Research mice were randomized to chow (n = 10), IV PN (n = 10), or intragastric (IG) PN (n = 10) and fed for 5 days. PECs were harvested at 2 or 4 hours after intraperitoneal injection of 2 mL of 1% glycogen. Intranuclear NFκB activity in PECs was examined by laser scanning cytometry. Cytokine (tumor necrosis factor‐α [TNF‐α], macrophage inflammatory protein‐2 [MIP‐2], interleukin‐10 [IL‐10]) levels in peritoneal lavaged fluid were determined by enzyme‐linked immunosorbent assay. Results: Intranuclear NFκB at 2 hours was significantly higher in the chow and IG‐PN groups than in the IV‐PN group. TNF‐α and IL‐10 levels of the chow group were significantly higher than those of IV‐PN mice at 2 hours, whereas those of IG‐PN mice were midway between those of the chow and IV‐PN groups. MIP‐2 was significantly higher in the chow group than in the IG‐PN and IV‐PN mice at 2 hours. TNF‐α levels correlated positively with intranuclear NFκB activity in PECs. Conclusions: Enteral nutrition may improve peritoneal defense by preserving early NFκB activation in PECs and cytokine responses.     

Bombesin Improves Adaptive Immunity of the Salivary Gland During Parenteral Nutrition

Background: The parotid and submandibular salivary glands are gut‐associated lymphoid tissues (GALTs) that secrete immune compounds into the oral cavity. Parenteral nutrition (PN) without enteral stimulation decreases GALT function, including intestinal lymphocyte counts and secretory immunoglobulin A (sIgA) levels. Since the neuropeptide bombesin (BBS), a gastrin‐releasing peptide analogue, stimulates intestinal function and restores GALT parameters, we hypothesized that PN + BBS would stimulate parotid and salivary gland IgA levels, T lymphocytes, and IgA plasma cell counts compared with PN alone. Methods: Male (Institute of Cancer Research) ICR mice received intravenous catheters and were randomized to chow with saline, PN, or PN + BBS (15 µg/tid/mouse) for 5 days (8/group), 2 days after cannulation. Salivary glands were weighed and either frozen for IgA and amylase analysis or fixed for histological analysis of acinar cells, IgA+ plasma cells, and T lymphocytes. Small intestinal wash fluid was collected for IgA regression analysis with salivary glands. Results: PN reduced organ weight, acinar cell size, and amylase activity compared with chow; BBS had no significant effects on these parameters. Compared with chow, PN significantly reduced salivary gland IgA levels, IgA+ plasma cells, and T lymphocytes. PN + BBS significantly elevated IgA and restored cellularity compared with PN. Salivary gland tissue homogenate IgA levels significantly correlated with intestinal fluid IgA levels. Conclusions: Compared with chow, PN results in atrophy of the salivary glands characterized by reduced amylase, IgA, and immune cellularity. BBS has no effect on acinar cells or amylase activity compared with PN but maintains tissue IgA and plasma cells and T‐lymphocyte numbers compared with chow.     

The Impact of Glutamine Dipeptide–Supplemented Parenteral Nutrition on Outcomes of Surgical Patients

Objective: To evaluate the impact of glutamine dipeptide–supplemented parenteral nutrition (GLN‐PN) on clinical outcomes in surgical patients. Methods: MEDLINE, EMBASE, Web of Science, and the Cochrane Controlled Clinical Trials Register were searched to retrieve the eligible studies. The studies were included if they were randomized controlled trials that evaluated the effect of GLN‐PN and standard PN on clinical outcomes of surgical patients. Clinical outcomes of interest were postoperative morbidity of infectious complication, mortality, length of hospital stay, and cost. Statistical analysis was conducted by RevMan 4.2 software from the Cochrane Collaboration. Results: Fourteen randomized controlled trials (RCTs) (N = 587) were included in this meta‐analysis. The results showed that glutamine dipeptide significantly reduced the length of hospital stay by around 4 days in the form of alanyl‐glutamine (weighted mean difference [WMD] = ?3.84; 95% confidence interval [CI] ?5.40, ?2.28; z = 4.82; P < .001) and about 5 days in the form of glycyl‐glutamine (WMD = ?5.40; 95% CI ?8.46, ?2.33; z = 3.45; P < .001). The overall effect indicated a significant decrease in the infectious complication rates of surgical patients receiving GLN‐PN (risk ratio = 0.69; 95% CI 0.50, 0.95; z = 2.26; P = .02). Conclusion: GLN‐PN was beneficial to postoperative patients by shortening the length of hospital stay and reducing the morbidity of postoperative infectious complications.     

Efficacy of Early Enteral Immunonutrition on Immune Function and Clinical Outcome for Postoperative Patients With Gastrointestinal Cancer

Background: Nutrition support is crucial for patients with gastrointestinal (GI) cancer after the operation. However, the controversy over the application of parenteral nutrition (PN) and early enteral immunonutrition (EEIN) has no determinate conclusion. Materials and Methods: We compared the effects of PN and EEIN on the postoperative nutrition condition, immune status, inflammation level, long‐term survival, and quality of life of the patients with GI cancer. Seventy‐eight patients were randomly divided into the PN group (n = 44) or EEIN group (n = 34). After an 8‐day nutrition treatment, clinical and immunological parameters were evaluated. Results: The EEIN group had a significantly shorter hospital stay and higher body mass index level on postoperative day 30 than those in the PN group (P < .05). However, total hospital cost and incidences of short‐term postoperative complications had no significant difference (P > .05). The percentages of CD4⁺, natural killer, and natural killer T lymphocyte cells and the ratio of CD4⁺/CD8⁺ in peripheral blood were significantly increased. Compared with the PN group, the EEIN group had a higher expression of activated cell surface markers such as CD27 and CD28. In addition, the secretion of interleukin (IL)–2 and interferon‐γ was significantly higher, and the secretion of tumor necrosis factor–α and IL‐10 was lower. Complication‐free survival in the EEIN group were longer than those in the PN group (P = .04). Conclusion: EEIN is superior to PN in improving nutrition status, enhancing immune function, and elevating quality of life.     

Oleanolic Acid Improves Gut Atrophy Induced by Parenteral Nutrition

Background: Nutrition support with parenteral nutrition (PN) is associated with gut atrophy. Prior studies have shown improvement with enteral chenodeoxycholic acid, a dual agonist for the farnesoid X receptor (FXR) and bile acid receptor TGR5. We hypothesized that gut growth is induced by TGR5 activation, and gut atrophy during PN administration could be prevented with the TGR5‐specific agonist oleanolic acid (OA). Methods: Neonatal pigs were implanted with duodenal and jugular vein catheters. Animals were provided equi‐nutritious PN or enteral swine milk. A PN subgroup received enteral OA at 50 mg/kg/d. Results: PN caused marked gut atrophy compared with enterally fed (EN) control animals. OA treatment led to preservation of gut mass demonstrated grossly and histologically. The mean ± SD gut weight as a percentage of body weight was 4.30 ± 0.26 for EN, 1.92 ± 0.06 for PN (P < .05, EN vs PN), and 3.39 ± 0.79 for PN+OA (P < .05, PN+OA vs PN). Mean ± SD gut density (g/cm) was 0.31 ± 0.03 for EN, 0.18 ± 0.03 for PN (P < .05 EN vs PN), and 0.27 ± 0.01 for PN+OA (P < .05 PN+OA vs PN). Histologically, a markedly decreased villous to crypt ratio was noted with PN, and OA significantly prevented this decrease. The mean ± SD v/c ratio was 3.51 ± 0.59 for EN, 1.69 ± 0.10 for PN (P < .05, EN vs PN), and 2.90 ± 0.23 for PN+OA (P < .05, PN+OA vs PN). Gut TGR5 messenger RNA expression was significantly elevated with OA treatment compared with both PN and EN. Conclusion: The bile acid–activated G protein–coupled receptor TGR5 agonist OA prevented gut atrophy associated with PN.     

Vitamin E in New‐Generation Lipid Emulsions Protects Against Parenteral Nutrition–Associated Liver Disease in Parenteral Nutrition–Fed Preterm Pigs

Introduction: Parenteral nutrition (PN) in preterm infants leads to PN‐associated liver disease (PNALD). PNALD has been linked to serum accumulation of phytosterols that are abundant in plant oil but absent in fish oil emulsions. Hypothesis: Whether modifying the phytosterol and vitamin E composition of soy and fish oil lipid emulsions affects development of PNALD in preterm pigs. Methods: We measured markers of PNALD in preterm pigs that received 14 days of PN that included 1 of the following: (1) Intralipid (IL, 100% soybean oil), (2) Intralipid + vitamin E (ILE, d‐α‐tocopherol), (3) Omegaven (OV, 100% fish oil), or (4) Omegaven + phytosterols (PS, β‐sitosterol, campesterol, and stigmasterol). Results: Serum levels of direct bilirubin, gamma glutamyl transferase, serum triglyceride, low‐density lipoprotein, and hepatic triglyceride content were significantly lower (P < .05) in the ILE, OV, and PS compared to IL. Hepatic cholesterol 7‐hydroxylase and organic solute transporter–α expression was lower (P < .05) and portal plasma FGF19 higher in the ILE, OV, and PS vs IL. Hepatic expression of mitochondrial carnitine palmitoyltransferase 1A and microsomal cytochrome P450 2E1 fatty acid oxidation genes was higher in ILE, OV, and PS vs IL. In vivo ¹³C‐CDCA clearance and expression of pregnane X receptor target genes, cytochrome P450 3A29 and multidrug resistance‐associated protein 2, were higher in ILE, OV, and PS vs IL. Conclusions: α‐tocopherol in Omegaven and added to Intralipid prevented serum and liver increases in biliary and lipidemic markers of PNALD in preterm piglets. The addition of phytosterols to Omegaven did not produce evidence of PNALD.     

Arginine Supplementation Induces Arginase Activity and Inhibits TNF‐α Synthesis in Mice Spleen Macrophages After Intestinal Obstruction

Background: The purpose of this study was to assess the effect of arginine supplementation on arginase activity, tumor necrosis factor–α (TNF‐α) and interleukin‐10 (IL‐10) synthesis in cultured splenic macrophages from a murine model of intestinal obstruction (IO). The effects of nitric oxide synthase (iNOS) inhibition were also studied using iNOS knockout animals. Material and Methods: Male C57BL6/J wild‐type (WT) and iNOS knockout (iNOS–/–) mice were randomized into 6 groups: Sham and Sham–/– (standard chow), IO and IO–/– (standard chow + IO), and Arg and Arg–/– (standard chow supplemented with arginine + IO). After 7 days of treatment with standard or supplemented chow, IO was induced. Arginase activity as well as TNF‐α and IL‐10 levels were analyzed in splenic macrophage cultures. Results: Arginine supplementation and the absence of iNOS increased arginase activity in splenic macrophages (Arg, IO–/–, and Arg–/– groups vs the Sham group; P < .05). Arginine was also related to a decrease in TNF‐α levels (Arg vs IO group, P < .05) and maintenance of IL‐10 levels (Arg vs other groups, P > .05). The inhibition of iNOS did not result in effects on the concentration of cytokines (Sham–/–, IO–/–, and Arg–/– vs other, P < .05). Conclusions: Arginine supplementation and iNOS inhibition led to increased arginase activity. Arginine availability decreased plasma TNF‐α levels, which may be directly related to nitric oxide derived from arginine.     

α-Linolenic Fatty Acid Supplementation Decreases Tumor Growth and Cachexia Parameters in Walker 256 Tumor-Bearing Rats

Fish oil (FO) has been shown to affect cancer cachexia, tumor mass, and immunity cell. n-3 PUFA, specifically α-linolenic fatty acid (ALA), has controversial effects. We investigated this in nontumor-bearing Wistar rats fed regular chow (C), fed regular chow and supplemented with FO or Oro Inca oil (OI), and Walker 256 tumor-bearing rats fed regular chow (W), fed regular chow and supplemented with FO (WFO) or OI (WOI). Rats were supplemented (1g/kg body weight/day) during 4 wk and then the groups tumor-bearing were inoculated with Walker 256 tumor cells suspension and 14 days later the animals were killed. WFO increased EPA fivefold and DHA 1.5-fold in the tumor tissue compared to W (P < 0.05). OI supplementation increased of threefold of ALA when compared to W (P < 0.05). Tumor mass in WFO and OI was of 2.3-fold lower, as well as tumor cell proliferation of 3.0-fold tumor tissue lipoperoxidation increased of 76.6% and cox-2 expression was 20% lower. Cachexia parameters were attenuate, blood glucose (25% higher), Triacylglycerolemia (50% lower), and plasma TNF-α (65% lower; P < 0.05) and IL-6 (62.5% lower). OI, rich in ALA, caused the same effect on cancer as those seen in FO.     

Cisplatin Upregulates Glutamine Transport in Human Intestinal Epithelial Cells

Background: Glutamine (GLN) prevents the intestinal mucosal injury induced by chemotherapy, although the mechanism of this protective action has not yet been elucidated. Amino acid transport across the plasma membrane is essential for supplying enterocytes with amino acids for cellular metabolism. It was hypothesized that chemotherapy stimulates GLN transport, which enables GLN to be used more efficiently as a metabolic fuel. Methods: A rat model was used to examine the effect of enteral GLN on intestinal mucosal injury induced by intraperitoneal injection of cisplatin (7.0 mg/kg of body weight). The effects of cisplatin on amino acid transport and the expression of messenger RNA and protein were evaluated by real‐time polymerase chain reaction and Western blot analysis, respectively, in the human intestinal epithelial cell line Caco‐2. The effects of cisplatin on glutaminase activity and intracellular glutathione were also studied. Results: GLN prevented mucosal atrophy induced by cisplatin in rats. In Caco‐2 cells, cisplatin significantly increased GLN transport and the expression of GLN transporter ASCT2 messenger RNA and protein. Leucine, but not glutamate, transport significantly increased in the cisplatin‐treated group due to the increase in LAT1 (leucine transporter) protein expression. Glutaminase activity and intracellular glutathione increased significantly in the cisplatin‐treated group. Conclusions: Bolus enteral GLN prevents intestinal mucosal injury induced by cisplatin in rats, as demonstrated by increased GLN transport and increased GLN transporter expression after cisplatin administration.     

Influence of adding pyrroloquinoline quinone to parenteral nutrition on gut-associated lymphoid tissue

Background: Experimental intravenous (IV) parenteral nutrition (PN) diminishes gut‐associated lymphoid tissue (GALT) cell number and function. PN solution cannot maintain GALT at the same level as a normal diet, even when delivered intragastrically (IG). Previous studies demonstrated pyrroloquinoline quinone (PQQ)–deficient mice to be less immunologically responsive. Because standard (STD) PN solution lacks PQQ, PQQ supplementation may prevent PN‐induced GALT changes. This study was designed to determine the influence of adding PQQ to PN on GALT. Methods: In experiment 1, mice (n = 32) were randomized to chow, IV‐STD‐PN, and IV‐PQQ‐PN groups. The chow group was fed chow with the same caloric content as PN. The IV‐STD‐PN group received STD‐PN solution, whereas the IV‐PQQ‐PN group was given PQQ (3 mcg/d)–enriched PN by the IV route. After 5 days of feeding, lymphocytes were isolated from the Peyer's patch (PPs), intraepithelial space (IE), and lamina propria (LP) of the small intestine. GALT lymphocyte number and phenotype (αβTCR+, γδTCR+, CD4+, CD8+, B220+ cells) and intestinal immunoglobulin A (IgA) level were determined. In experiment 2, mice (n = 28) were randomized to IG‐STD‐PN or IG‐PQQ‐PN group. After IG nutrition supports, GALT mass and function were determined as in experiment 1. Results: The IV‐PQQ‐PN group showed increased PP lymphocyte number and PP CD8+ cell number compared with the IV‐STD PN group. The IG‐PQQ‐PN group had significantly greater PP lymphocyte number and PP CD4+ cell numbers than the IG‐STD‐PN group. Neither IV nor IG PQQ treatment raised IgA level. Conclusions: PQQ added to PN partly restores GALT mass, although its effects on GALT function remain unclear.     

Enteral feeding of a chemically defined diet preserves pulmonary immunity but not intestinal immunity: the role of lymphotoxin beta receptor

BACKGROUND: Compared with chow or a complex enteral diet (CED), IV administration of a parenteral nutrition solution (IV-PN) impairs intestinal and respiratory mucosal immunity, resulting in cellular and immunoglobulin A (IgA) defects in the intestine and impaired respiratory antiviral and antibacterial defenses. PN given intragastrically (IG-PN) impairs intestinal immunity similar to IV-PN but preserves antiviral defences and partially preserves antibacterial defenses. Lymphotoxin beta receptor (LTbetaR) is a molecule essential for development and organization of lymphoid tissue. It controls many molecules important in mucosal immune integrity. This study examines effects of route (IV or enteral) and type (PN, CED, or chow) on murine intestine and lung LTbetaR expression. METHODS: Forty-three mice randomly received IV-PN (n = 12), IG-PN (n = 11), IV saline + chow (chow; n = 11), or a CED (n = 9). After 5 days of feeding, intestinal and lung samples were obtained and processed for levels of LTbetaR by Western blot. RESULTS: IV-PN significantly reduced intestinal and lung LTbetaR compared with CED and chow. IG-PN reduced LTbetaR levels only in the intestine but preserved lung levels. CONCLUSIONS: Route and type of nutrition differentially influence molecular events in the intestinal and respiratory mucosal immune systems. Enteral feeding with any diet (complex or chemically defined) maintains lung LTbetaR expression, whereas intestinal LTbetaR levels are maintained only with CEDs (chow and CED). We hypothesize that LTbetaR is responsible for the observed preservation of respiratory tract immunity with administration of a noncomplex, chemically defined enteral diet, whereas intestinal immunity is compromised with this diet.