Glutamine infusion during ischemia is detrimental in a murine gut ischemia/reperfusion model

BACKGROUND

Gut ischemia/reperfusion (I/R) frequently occurs in clinical settings as a result of disproportionate splanchnic hypoperfusion during shock. Glutamine (GLN) supplementation of total parenteral nutrition (TPN) before gut I/R improves survival after gut I/R compared with standard TPN. However, it is unknown whether GLN treatment after the occurrence of the insult is beneficial or not. The aims of this study were to examine effects of GLN infusion during gut ischemia on survival, myeloid cell (neutrophils + monocytes) activation, and vascular permeability in organs.

METHODS

Male Institute of Cancer Research (ICR) mice were randomized to control and GLN groups. After IV cannulation, mice underwent 90 (experiments 1 and 2) or 60 (experiment 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the GLN group was given 3% GLN solution. In experiment 1, survival rates were monitored for 72 hours (n = 25). In experiment 2, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 17). Reactive oxygen intermediate (ROI) production by myeloid cells was determined by flow cytometry using dihydrorhodamine 123 with or without phorbol myristate acetate stimulation. Expression of CD11a and CD11b on myeloid cells was also measured. Myeloperoxidase (MPO) activity in the lung was evaluated. In experiment 3, vascular permeability in organs was measured using Evans blue at 2 or 4 hours.

RESULTS

In experiment 1, survival time in the GLN group was significantly reduced compared with the control group (p = .02, log-rank test). The survival rates were 92% (12/13) and 42% (5/12) for the control and GLN groups at 12 hours (p = .01) and 38% (5/13) and 0% (0/12) at 48 hours (p = .02), respectively. In experiment 2, ROI production was significantly higher in the GLN group than in the control group after PMA stimulation both at 2 and 4 hours. CD11b expression was significantly higher in the GLN group than in the control group at 4 hours. There was no difference in pulmonary MPO activity at either time point. In experiment 3, GLN infusion significantly increased hepatic vascular permeability compared with saline infusion at 4 hours.

CONCLUSIONS

GLN infusion during ischemia is detrimental for survival after gut I/R. A possible mechanism is excessive priming of myeloid cells caused by GLN infusion. Timing of GLN administration is critical for outcome after gut ischemic insult.

Differences in ICAM-1 and TNF-alpha expression between large single fraction and fractionated irradiation in mouse brain

PURPOSE

To elucidate the brain molecular response to irradiation. The expression of the intercellular adhesion molecule (ICAM-1) and tumour necrosis factor-alpha (TNF-alpha) in the mouse brain was compared after single-dose and fractionated whole-brain irradiation.

MATERIALS AND METHODS

Mice received a single dose of 2, 10 or 20 Gy or a fractionated dose (2 Gy day(-1)) of 10, 20 or 40 Gy. ICAM-1, and TNF-alpha mRNA expression were quantified by the highly sensitive real-time polymerase chain reaction technique. Expression of ICAM-1 protein was quantified by dual-labelled monoclonal antibody assay.

RESULTS

After a 20-Gy single dose, there was an increase in ICAM-1 and TNF-alpha mRNA levels (14- and 11-fold, respectively) as well as a significant increase in the level of ICAM-1 protein (p=0.0243). The expression of ICAM-1 and TNF-alpha mRNA increased at the end of the 40-Gy fractionated regimen (3.55- and 2.30-fold, respectively).

CONCLUSIONS

The molecular response of the brain to single-dose irradiation was rapid, while its response to fractionated irradiation was slow. This finding is consistent with clinical observations and could be of use when designing strategies to mitigate radiation sequelae.

Route of nutrition influences generation of antibody-forming cells and initial defense to an active viral infection in the upper respiratory tract

OBJECTIVE

To assess whether lack of enteral feeding significantly impairs generation of specific immune responses to an acute viral infection.

SUMMARY BACKGROUND DATA

Parenteral feeding provides adequate nutrients to meet metabolic needs, but lack of enteral stimulation creates a defect in mucosal immunity characterized by loss of IgA-mediated defenses in the respiratory tract.

METHODS

The enzyme-linked Immunospot (ELISPOT) assay was used to determine accumulation of immunologic cells in the nasal passages after diet manipulation. Viral shedding and nasal IgA levels were measured in additional groups of mice.

RESULTS

After determining the time course of antibody-forming cells (AFCs) via ELISPOT to an active infection with the A/PR8 influenza virus, a significant reduction was found in total AFCs, IgA-producing AFCs, and IgG-producing AFCs over the course of a 13-day experiment with significant depression in viral-specific respiratory IgA levels. Eight days following an active infection, seven of nine total parenteral nutrition-fed animals continued to have viral shedding in the nasal passages compared to one of nine chow-fed mice and one of six animals fed a complex enteral diet.

CONCLUSIONS

Lack of enteral stimulation significantly impairs the generation of IgA-mediated mucosal immunity.

Oral administration of Bifidobacterium longum culture condensate in a diet-restricted murine peritonitis model enhances polymorphonuclear neutrophil recruitment into the local inflammatory site

Dietary restriction impairs polymorphonuclear neutrophil (PMN) recruitment into the local inflammatory site, resulting in susceptibility to infection. Probiotics enhance host immunity via conditioning host intestinal microflora. Oral administration of Bifidobacterium longum culture condensate (BCC) in a diet-restricted murine peritonitis model may enhance PMN recruitment into the inflammatory site. Male ICR mice (n = 40) were assigned in equal numbers to control or BCC groups and subjected to 75% restricted food intake for 7 d. During dietary restriction, controls received only standard mouse chow, whereas the BCC group received standard mouse chow containing 1% BCC. Mice were killed before (0 h) or after (2 or 4 h) intraperitoneal glycogen injection. Peritoneal lavage fluid and exudative cells were recovered by peritoneal lavage. Peritoneal exudative cell number was counted. Tumor necrosis factor-alpha, interleukin-6, macrophage inflammatory protein-2, and interleukin-10 concentrations in peritoneal lavage fluid were determined by enzyme-linked immunosorbent assay. CD11b, CD18, CD31, and CD62L expressions on circulating PMNs were measured by flow cytometry. Oral BCC administration upregulated PMN recruitment into the peritoneal cavity and increased peritoneal fluid cytokine concentrations as well as CD18 and CD62L expressions on circulating PMNs during glycogen-induced peritonitis. Oral BCC administration in a diet-restricted murine peritonitis model augmented PMN recruitment into the inflammatory site by upregulating cytokine concentrations in the local inflammatory site and adhesion molecule expression on circulating PMNs. Oral BCC administration may be a favorable modality for improving dietary restriction-induced host immunosuppression.

Analysis of tyrosine phosphorylation in resident peritoneal cells during diet restriction by laser scanning cytometry

Tyrosine phosphorylation plays a critical role in signal transduction pathways in immune cells. Laser scanning cytometer (LSC), a newly developed microscope-based cytofluorometer, may overcome shortcomings of Western blotting and flow cytometry in the detection of intracellular signaling transduction. The aims of this study were to visualize and quantitate intracellular phosphotyrosine in the peritoneal cells harvested from diet-restricted mice by LSC. In addition, using LSC, we identified the main cell type with activated tyrosine phosphorylation in response to an inflammatory stimulus and we investigated the intracellular distribution of tyrosine phosphorylation within the peritoneal macrophages. Mice were assigned to the ad libitum and diet-restricted, i.e., 75% restricted food intake, groups. After 7 days of pair feeding, the peritoneal cells were harvested. Tyrosine phosphorylation in the harvested cells with either N-formyl-methionyl-leucyle-phenylalanine (fMLP) or lipopolysaccharide (LPS) stimulation was examined using LSC. Tyrosine phosphorylation of peritoneal cells from the diet-restricted group was significantly higher than that from the ad libitum group, regardless of stimulation. Stimulation of peritoneal cells with either fMLP or LPS significantly increased tyrosine phosphorylation in the ad libitum group, but not in the diet-restricted group. The relocation feature of LSC revealed that the cells with distinct tyrosine phosphorylation were macrophages. Topographic analysis demonstrated that phosphotyrosine was localized mainly in the cytoplasm of these cells. In summary, LSC revealed that tyrosine phosphorylation is mainly in the cytoplasm of the peritoneal macrophages and is deranged by diet restriction. LSC is a powerful tool for the study of intracellular signaling transduction.

Diminished lung injury with vascular adhesion molecule-1 blockade in choline-deficient ethionine diet-induced pancreatitis

BACKGROUND

Lung injury in severe acute pancreatitis is mediated by infiltrating leukocytes. Our laboratory has previously demonstrated that acute lung injury in acute pancreatitis results in an up-regulation of vascular adhesion molecule-1 (VCAM-1) cell surface receptor expression on pulmonary vascular endothelium and neutrophil sequestration. The objective of this study was to determine whether blocking expression of VCAM-1 in acute pancreatitis would modify acute pulmonary injury.

METHODS

Young female mice were fed a choline-deficient ethionine (CDE) supplemented diet to induce acute pancreatitis. After initiation of the diet, one group (acute pancreatitis treated [n = 18]) was treated with blocking doses (2.35 mg/kg) of monoclonal anti-VCAM-1 receptor antibody (Ab) at 48, 96, and 120 hours. A second group (acute pancreatitis treated control [n = 5]) was treated with a similar dose of an isotypic control for VCAM-1 (nonbinding Ab) at the same time points. A third group (acute pancreatitis untreated [n = 12]) received a CDE diet, and a fourth group (control [n = 11]) received standard food with no Ab treatment. All animals were killed at 144 hours. The dual radiolabeled monoclonal Ab method was used to quantitate VCAM-1 cell surface expression in lung tissue. Lung injury was assessed histologically, and apoptosis was detected by transferase-mediated deoxyuridine triphosphate nick end labeling assay. Pulmonary leukocyte sequestration was determined by myeloperoxidase (MPO) assay and CD18 staining.

RESULTS

Pulmonary VCAM-1 cell surface expression was significantly increased in animals with acute pancreatitis when compared to controls (P <.001) and was reduced to near control levels in acute pancreatitis treated animals. On histologic examination, treated animals with acute pancreatitis exhibited significantly less lung injury and apoptosis than did untreated animals with acute pancreatitis. Leukocyte sequestration and MPO activity were significantly reduced in the treated animals with pancreatitis compared to untreated animals with pancreatitis (P <.0001) or acute pancreatitis treated controls (P <.03).

CONCLUSIONS

Blocking VCAM-1 on pulmonary vascular endothelium decreases leukocyte adherence and recruitment into the lung, hence reducing lung injury in severe acute pancreatitis. Clinically, VCAM-1 antagonism may be an important adjunct to evolving therapy for distant organ injury in severe acute pancreatitis.

Diet restriction impairs extracellular signal-regulated kinase activation of peritoneal exudative cells after N-formyl-methionyl-leucyl-phenylalanine stimulation in a murine peritonitis model

BACKGROUND

Phosphorylation of extracellular signal-regulated kinase (ERK) enhances various inflammatory responses in immune cells. It is unknown whether dysfunction of immune cells during malnutrition is attributed to derangement of ERK activation.

METHODS

Male Institute of Cancer Research (ICR) mice received chow (146 g/kg per day, ad libitum or 36.5 g/kg per day, diet-restricted) for 7 days. Mice (n = 55) were given 6.5 mg/kg of an ERK inhibitor (PD98059) or vehicle intraperitoneally (IP), at 2 hours before cecal ligation and puncture (CLP). Survival was observed up to 60 hours. Detection of phosphorylated ERK (pERK) in the peritoneal exudative cells (PECs) was done as follows. In a separate study, PECs were harvested by peritoneal lavage 2 hours after an IP injection of 1% glycogen. PECs were incubated with or without 100 nmol/L N-formyl-methionyl-leucyl-phenylalanine (fMLP) for 1 minute. PEC ERK activation was detected with Western blot analysis (n = 38), by densitometric quantification, and with a laser scanning cytometer (LSC; n = 13). Subpopulations of PECs were determined by Wright-Giemsa staining. Unstimulated pERK expression was normalized to 100% for Western blot analysis.

RESULTS

Diet restriction reduced survival after CLP compared with the ad libitum mice. ERK inhibition showed no effect on survival in diet-restricted mice but reduced survival in ad libitum mice. There were no differences in subpopulations of PECs 2 hours after glycogen injection between the groups. Western blot analysis revealed that fMLP stimulation significantly increased the phosphorylation of ERK1/2 in PECs from the ad libitum group (ERK1, 199 +/- 41%; ERK2, 211 +/- 49%; p < .03) but not in those from diet-restricted mice (ERK1, 98 +/- 10%; ERK2, 91 +/- 9%). Mean fluorescence intensity (MFI) of pERK in PECs obtained by LSC was significantly elevated after fMLP in the ad libitum group (from 19.4 +/- 1.5 MFI to 22.4 +/- 1.2 MFI; p < .05) but did not change in the diet-restricted group (from 19.4 +/- 1.8 MFI to 19.1 +/- 1.5 MFI).

CONCLUSIONS

ERK activation is essential for survival in this murine sepsis model. Impaired ERK activation of PECs may, at least in part, impair host defense during malnutrition.

Increased ICAM-1 and beta2 integrin expression in parenterally fed mice after a gut ischemic insult

Lack of enteral feeding increases P- and E-selectin and ICAM-1 expression on endothelial cells in organs, such as the small intestine and lung, and increases neutrophils in the intestine. These changes are associated with increased mortality after gut ischemia. We hypothesize that nutritional regimen affects endothelial ICAM-1 levels and leukocyte beta2 integrins after gut ischemia. Mice received chow, intravenous (IV) TPN, or intragastric (IG) TPN. In experiment 1, after 5 days of diet, 28 mice underwent 15 min of superior mesenteric artery (SMA) occlusion (I/R) for quantification of ICAM-1 expression in organs 3 h later. In experiment 2, after the same nutrient pretreatments of 38 mice, peripheral blood was obtained with or without gut I/R to measure CD11a and CD11b expression on myeloid cells. CD18 immunofluorescence staining was studied in the lung. Expression of ICAM-1 in the liver, kidney, and small intestine was significantly higher after IV-TPN than chow. IG-TPN reduced liver and kidney ICAM-1 levels midway between the chow and IV-TPN groups, but not intestinal expression. Expression of CD11b on the myeloid cell population in each group was similar before I/R, but CD11b levels increased after IV-TPN on circulating cells after I/R compared with all uninjured animals or injured chow or IG-TPN mice. Only IV-TPN mice had lung CD18-positive leukocytes after I/R. After I/R, lack of enteral feeding increases organ expression of ICAM-1, CD11b levels on myeloid cells, and lung of CD18 positive leukocytes. Through these changes, lack of enteral feeding may increase organ damage after gut ischemia.

Differences in neutrophil death among beta-lactam antibiotics after in vitro killing of bacteria

Antibiotic therapy is an essential treatment for gram-negative bacterial infections. Antibiotic-induced endotoxin release and subsequent production of inflammatory cytokines reportedly depend on the type of antibiotic action. This study examined the effects of various beta-lactam antibiotics on cell death of human polymorphonuclear neutrophils (PMNs) cocultured with Escherichia coli (E. coli) in vitro. E. coli morphology after antibiotic treatment was determined. PMNs and E. coli were cocultured with antibiotics for 0, 4, or 12 h. Levels of endotoxin and cytokines (TNF-alpha, IL-1beta, and IL-6) in the supernatants were measured. The filtrates of antibiotic-treated E. coli supernatants were cocultured with PMNs for 0, 4, or 12 h. In all experiments, ampicillin (ABPC), cefazolin sodium (CEZ), cefoperazone sodium (CPZ), latamoxef sodium (LMOX), imipenem (IPM), and polymyxin B sulfate (PLB) were used at 30 microg/mL. PMNs were isolated from healthy volunteers. PMN cell death was assessed by flow cytometry and light microscopy. ABPC, CEZ, CPZ, and LMOX, which induce bacterial filament formation with lysis, caused PMN necrosis when cocultured with E. coli. In contrast, IPM, which induces bacterial spheroplast formation with lysis, caused PMN apoptosis. Levels of endotoxin, TNF-alpha and IL-6 in the supernatants with IPM and PLB were significantly lower than in those with other beta-lactam antibiotics. The filtrates of IPM- and PLB-treated E. coli supernatants induced PMN apoptosis, whereas those treated with other beta-lactam antibiotics increased PMN necrosis. Beta-lactam antibiotics have different impacts on the types of PMN cell death after E. coli killing. Underlying mechanisms and the clinical relevance of IPM-induced PMN apoptosis in severe gram-negative infection warrant further investigation.

Total parenteral nutrition supplementation with glutamine improves survival after gut ischemia/reperfusion

BACKGROUND

Total parenteral nutrition (TPN) alters gut cytokines and mucosal immunity and increases intercellular adhesion molecule-1 (ICAM-1) expression, gut neutrophil levels, and mortality after gut ischemia. Supplementation of TPN with glutamine partially supports mucosal immunity by preserving respiratory and intestinal IgA levels, maintaining the proper IgA-stimulating cytokine milieu within the intestine, and reducing intestinal ICAM-1 expression and neutrophil accumulation. This work investigates whether glutamine supplementation of TPN affects mortality in mice after gut ischemic insult.

METHODS

Thirty-eight mice were randomized to receive chow, TPN, or 2% glutamine-supplemented TPN (GLN-TPN) for 5 days. After feeding their respective diets, gut ischemia/reperfusion (I/R) was induced with superior mesenteric artery occlusion for 30 minutes followed by resuscitation with 1 mL saline. Survival was recorded until 72 hours after reperfusion.

RESULTS

Survival time was significantly reduced in the TPN-fed mice compared with both chow-fed and GLN-TPN-fed mice (p < .05). Survival at 72 hours after reperfusion was also significantly lower in the TPN-fed mice than in the chow-fed and GLN-TPN-fed mice (p < .05)

CONCLUSIONS

Glutamine supplementation of TPN significantly improves survival after gut I/R, suggesting modulation of the inflammatory response or improved gut tolerance to low-flow states.

The neuropeptide bombesin improves IgA-mediated mucosal immunity with preservation of gut interleukin-4 in total parenteral nutrition-fed mice

BACKGROUND

The Th2 cytokines, interleukin-4 (IL-4) and interleukin-10 (IL-10), stimulate IgA production. Total parenteral nutrition (TPN) reduces IL-4 and IL-10 messenger RNA in gut lamina propria lymphocytes, total IL-4 and IL-10 in gut homogenates, and IgA-mediated mucosal immunity. Bombesin (BBS) can maintain mucosal immunity in TPN-fed mice, but the effects of BBS on gut IL-4 and IL-10 levels and their mRNA expression in the lamina propria are unknown.

METHODS

In experiment 1, mice that were fed chow, TPN, or TPN + BBS (15 microg/kg intravenously-three times a day) for 5 days were killed, and respiratory tract IgA and intestinal IgA, IL-4, and IL-10 levels were measured. In experiment 2, IL-4 and IL-10 mRNA were measured in isolated lamina propria lymphocytes from chow-, TPN-, and TPN+BBS-fed mice by reverse transcriptase-polymerase chain reaction. Intestines were harvested 1 hour after injection of 100 7 microg of lipopolysaccharide intraperitoneally. Samples were standardized to beta-actin.

RESULTS

TPN-fed mice had significantly lower respiratory tract IgA levels than chow- or TPN + BBS-fed mice. TPN+BBS did not increase intestinal IL-10 or IL-10 lamina propria mRNA levels but maintained intestinal IL-4 levels and lamina propria IL-4 mRNA expression equal to those of chow-fed mice.

CONCLUSIONS

BBS reverses the effects of TPN on intestinal and respiratory tract IgA levels and most effects on gut cytokines. Lamina propria cytokine mRNA levels reflect total gut cytokine concentration.

Effects of tyrosine kinase signaling inhibition on survival after cecal ligation and puncture in diet-restricted mice

BACKGROUND

Malnutrition impairs host immunity, resulting in high mortality and morbidity due to infections. Phosphorylation of protein tyrosine kinase (PTK) is a key step in the signaling of many cellular functions, including immune cell functions. Malnutrition may affect this signaling in response to surgical insults. The aim of this study was to examine the effects of PTK inhibition on mortality in ad libitum and in diet-restricted mice after cecal ligation and puncture (CLP). Moreover, tyrosine phosphorylation of peritoneal cells from these animals was evaluated.

METHODS

Survival study: Mice (n = 45) received chow, 146 g/kg per day (ad libitum) or 36.5 g/kg per day (diet-restricted), for 7 days. Two hours before CLP, one-half the mice in each group were given a tyrosine kinase inhibitor, AG 556 (3.0 mg/kg i.p.), and the others received vehicle. Survival was observed up to 7 days after CLP. Effects of AG 556 on survival with a lesser degree of malnutrition (chow 73 g/kg per day) were also examined (n = 41). Measurement of tyrosine phosphorylation: mice (n = 20) were assigned to the ad libitum and diet-restricted (chow 36.5 g/kg per day) groups. Peritoneal cells were harvested either before or 2 hours after glycogen injection. Glycogen treatment elicits polymorphonuclear neutrophil influx into the peritoneal cavity. The cells were incubated with or without N-formyl-methionyl-leucyl-phenylalanine (fMLP). Tyrosine phosphorylation in the cells was examined using flow cytometry, laser scanning cytometry, and Western blotting.

RESULTS

Diet restriction significantly reduced survival compared with the ad libitum group. AG 556 treatment decreased the survival of ad libitum, but not in diet-restricted mice in both survival experiments. Stimulation of peritoneal cells with fMLP increased tyrosine phosphorylation in the ad libitum group (23% increase before glycogen and 18% after glycogen), but not in the diet-restricted group (-9% before glycogen and 3% after glycogen).

CONCLUSIONS

Inhibition of tyrosine kinase signaling impairs the ability of a well-nourished host to survive CLP-induced sepsis, while having no effects on survival in diet-restricted mice. Peritoneal cells from diet-restricted animals are unable to increase PTK phosphorylation in response to stimulation, which may be the mechanism underlying impaired host defense during malnutrition.

Ex vivo fluorescence microscopy provides simple and accurate assessment of neutrophil-endothelial adhesion in the rat lung

Neutrophil adhesion to the pulmonary endothelium is prerequisite to neutrophil transmigration and activation, both of which may lead to lung injury. A simple method to evaluate neutrophil adherence in the lung would be useful for developing new strategies for neutrophil-mediated lung injury. The purpose was to establish a simple method to evaluate neutrophil adhesion in the lung using ex vivo fluorescence microscopy. Rats were anesthetized, and the right jugular veins were catheterized. Neutrophils were isolated from another set of rats and labeled with 5,(6)-carboxyfluorescein diacetate. Animals were killed 120 s after a 1 x 10(6) labeled neutrophil injection. The pulmonary labeled neutrophil number was counted under a fluorescence microscope. In the first experiment, rats were given 0, 20, 200, or 2000 microg/kg lipopolysaccharide (LPS) i.p. At 4 h after challenge, the pulmonary labeled neutrophil number was determined. Kinetic studies were also performed at 0, 1, 4, and 8 h after 200 microg/kg LPS. Finally, anti-ICAM-1 Ab was injected i.v. before LPS 200 microg/kg, and the labeled neutrophil number in the lung was determined at 4 h. The number of pulmonary labeled neutrophils was higher after LPS 200 or 2000 microg/kg than after the other doses. The pulmonary labeled neutrophil number was increased at 4 h compared with the other time points. ICAM-1 blocking normalized the pulmonary labeled neutrophil number in the LPS group. In conclusion, our method seems to reflect ICAM-1-mediated neutrophil adherence to the endothelium in the present setting. This simple technique may be useful for evaluating neutrophil adhesion.

Enteral nutrition prevents remote organ injury and death after a gut ischemic insult

OBJECTIVE

To determine whether parenteral feeding (IV-TPN) influences the local and systemic response to an intestinal insult.

SUMMARY BACKGROUND DATA

Parenteral feeding increases ICAM-1 expression and attracts neutrophils (PMNs) to the intestine compared with enterally fed animals. Because the gut is a priming bed for PMNs, the authors hypothesized that IV-TPN may affect organ injury after gut ischemia-reperfusion (I/R).

METHODS

Mice were randomized to chow, IV-TPN, intragastric TPN, or complex enteral diet for 5 days' feeding. In experiment 1, 162 mice underwent 15 or 30 minutes of gut I/R, and death was recorded at 72 hours. In experiment 2, 43 mice underwent 15 minutes of gut ischemia and permeability was measured by 125I-labeled albumin at 3 hours after reperfusion. Lung PMN accumulation was measured by myeloperoxidase assay. In experiment 3, albumin leak was tested in the complex enteral diet group (n = 5) and the intragastric TPN group (n = 5) after 30 minutes of gut ischemia and 1 hour of reperfusion.

RESULTS

In experiment 1, enteral feeding significantly reduced the death rate compared with IV-TPN after 15 minutes of I/R. After 30 minutes of gut ischemia, the IV-TPN and intragastric TPN groups showed a higher death rate than the chow and enteral diet groups. In experiment 2, IV-TPN significantly increased pulmonary and hepatic 125I albumin leak compared with enteral feeding without increasing pulmonary myeloperoxidase levels. In experiment 3, there were no differences in 125I albumin leak between the complex enteral diet and intragastric TPN groups.

CONCLUSION

Enteral feeding reduced the death rate and organ permeability after 15 minutes of ischemia. However, prolonged ischemia (30 minutes) eliminated any benefits of intragastric TPN on survival.

Lack of enteral feeding increases expression of E-selectin after LPS challenge

BACKGROUND

Total parenteral nutrition (IV-TPN) increases neutrophil accumulation in the small intestine, expression of intestinal ICAM-1 and P-selectin, and upregulates E-selectin expression in the lung. Endothelial activation induced by lack of enteral nutrition may change the response to injury or infection. This study investigated whether nutrition influenced the expression of the adhesion molecule, E-selectin and ICAM-1, following endotoxin challenge.

MATERIALS AND METHODS

Forty-three mice were injected with saline, 2, 20, 200, 2000, or 10000 microg/kg lipopolysaccharide (LPS) intraperitoneally. E-selectin expression in the lung, small intestine, and heart was quantified at 3 h after challenge, while ICAM-1 was measured at 5 h, using the dual-radiolabeled monoclonal antibody technique. Next, 80 mice were fed chow, intragastric (IG)-TPN, or IV-TPN for 5 days, and then received intraperitoneal 2 or 200 microg/kg LPS. E-selectin and ICAM-1 expression in organs was measured at 3 and 5 h after endotoxin, respectively.

RESULTS

E-selectin expression in organs increased LPS dose dependently. ICAM-1 levels reached early peaks in the lung and in the intestine. Also, IV-TPN significantly increased E-selectin expression in the small intestine and tended to increase pulmonary E-selectin, when compared to chow or IG-TPN animals. There were no significant differences in E-selectin expression among three diet groups after 200 microg/kg LPS challenge. No differences in ICAM-1 expression were observed in any organ among the three groups after 2 or 200 microg/kg LPS injection.

CONCLUSIONS

E-selectin rather than ICAM-1, because of the expression pattern after various dosages of LPS challenge, may be a determining factor for the degree of LPS-induced inflammation at the early phase. Lack of enteral nutrition may increase inflammatory response through enhanced gut E-selectin levels after a small dose of LPS.

TPN decreases IL-4 and IL-10 mRNA expression in lipopolysaccharide stimulated intestinal lamina propria cells but glutamine supplementation preserves the expression

Total parenteral nutrition (TPN) decreases intestinal IgA and levels of Th2 cytokines, interleukin (IL)-4, and IL-10 within the supernatants of intestinal homogenates. These cytokines are known to stimulate IgA production in vitro by cells of the gut-associated lymphoid tissue (GALT). Glutamine (GLN) supplementation of TPN normalizes GALT mass and cytokine levels. Because intestinal homogenates contain mucosa which itself is a source of cytokines, it was unclear whether cytokines change within the GALT itself. This study investigates dietary effects on IL-4 and IL-10 cytokine mRNA expression within isolated GALT lamina propria cells after lipopolysaccharide (LPS) stimulation. Prospective randomized experimental trials were used in this study. Fifty-nine mice were randomized to chow, intravenous TPN (IV-TPN), intragastric TPN (IG-TPN), complex enteral diet (CED), or 2% GLN-supplemented TPN (GLN-TPN). In experiment 1, animals were fed chow, IV-TPN, IG-TPN, or CED for 5 days and received intraperitoneal LPS (100 microg/kg BW), and then were sacrificed 1 h later. Intestine was harvested for GALT lamina propria. Total RNA was extracted from lamina propria cells and cytokine mRNA for IL-4, and IL-10 was measured by reverse transcriptase polymerase chain reaction. IgA levels of intestinal washing were also measured with ELISA. In experiment 2, mRNA for IL-4 and IL-10, and intestinal IgA levels were measured in mice fed chow, IV-TPN, or GLN-TPN as in experiment 1. Both IL-4 and IL-10 mRNA expression decreased significantly in IV-TPN mice compared to chow or CED feeding. IG-TPN resulted in IL-10 mRNA expression significantly lower than chow or CED but significantly better than IV-TPN. GLN preserved IL-4 and IL-10 mRNA levels, which correlated with intestinal IgA levels. Route and type of nutrition as well as GLN influence message for the Th2 type IgA-stimulating cytokines, IL-4 and IL-10, within the primary site of GALT IgA production, the lamina propria.

Dietary restriction impairs neutrophil exudation by reducing CD11b/CD18 expression and chemokine production

HYPOTHESIS

Patients with malnutrition are susceptible to infection. Polymorphonuclear neutrophils (PMNs) are the major effector of the nonspecific immune response in host resistance to infection. Dietary restriction may impair PMN-mediated immunity in the peritoneal cavity by reducing PMN exudation, adhesion molecule expression on PMNs, and chemokine production.

DESIGN

Randomized study of murine glycogen-induced peritonitis with dietary restriction.

SETTING

University research laboratory.

MATERIALS

Male C57BL/6J mice.

INTERVENTIONS

Mice (N = 204) were assigned to ad libitum, moderate, and severe diet-restricted groups receiving mouse chow ad libitum (132 g/kg, 66 g/kg, and 33 g/kg daily for 7 days, respectively). After dietary restriction with or without 1 day of refeeding, mice were administered glycogen intraperitoneally to induce cell exudation.

MAIN OUTCOME MEASURES

CD11b, CD18, and CD62L expressions on circulating PMNs, phagocytosis, and reactive oxygen intermediate production by exudative PMNs were measured after glycogen installation. The levels of PMN-specific chemokine, macrophage inflammatory protein 2 (MIP-2), in peritoneal lavage fluid were also measured. These parameters were measured after glycogen installation in the refeeding experiment.

RESULTS

Seven days of dietary restriction decreased CD11b/CD18 expression on circulating PMNs, MIP-2 levels in peritoneal lavage fluid, and subsequent PMN exudation into the peritoneal cavity early in peritonitis. Both CD11b and CD18 expression on circulating PMNs and MIP-2 levels correlated significantly with numbers of exudative PMNs. Seven days of dietary restriction also impaired phagocytosis, while up-regulating reactive oxygen intermediate production by exudative PMNs. Only 1 day of ad libitum refeeding normalized CD11b/CD18 expression with PMN exudation into the peritoneal cavity.

CONCLUSIONS

Short-term dietary restriction impairs PMN exudation into local inflammatory sites in murine peritonitis by reducing CD11b/CD18 expression and MIP-2 production. Even brief nutritional replenishment in diet-restricted patients may improve host defense via restoring these PMN functions and chemokine production at local inflammatory sites.

Blocking pulmonary ICAM-1 expression ameliorates lung injury in established diet-induced pancreatitis

OBJECTIVE

To determine whether blocking the cell surface expression of intracellular adhesion molecules (ICAM-1) in established severe acute pancreatitis (AP) would ameliorate pulmonary injury.

SUMMARY BACKGROUND DATA

Lung injury in AP is in part mediated by infiltrating leukocytes, which are directed to lung tissue by ICAM-l. The authors' laboratory has previously demonstrated that AP results in overproduction of inflammatory cytokines, upregulation of pulmonary ICAM-1 expression, and a concomitant infiltration of neutrophils, which results in lung injury.

METHODS

Young female mice were fed a choline-deficient/ethionine-supplemented diet to induce AP and were treated with a blocking dose of monoclonal antibody specific to the ICAM-1 receptor. Antibody treatment was administered at 72, 96, and 120 hours after beginning the diet, and all animals were killed at 144 hours. The degree of pancreatitis was evaluated by serum biochemical and tumor necrosis factor alpha levels as well as histology. The dual radiolabeled monoclonal antibody method was used to quantitate ICAM-1 cell surface expression in pulmonary tissue. Lung injury was assessed histologically and by determining lung microvascular permeability by measuring accumulated 125I-radiolabeled albumin. Pulmonary neutrophil sequestration was determined by the myeloperoxidase assay.

RESULTS

All mice developed severe AP, and pancreatic injury was equally severe in both treated and untreated groups. Pulmonary ICAM-1 expression was significantly upregulated in animals with AP compared with controls. Treatment with a blocking dose of anti-ICAM-1 antibody after the induction of AP resulted in inhibited ICAM-1 cell surface expression to near control levels. Compared to untreated animals with AP, mice treated with anti-ICAM-1 mice had significantly reduced histologic lung injury and neutrophil sequestration, and a decreased microvascular permeability by more than twofold.

CONCLUSIONS

These results demonstrate for the first time that treatment targeting the cell surface expression of ICAM-1 after the induction of AP ameliorates pulmonary injury, even in the face of severe pancreatic disease.

Impairment of mucosal immunity by total parenteral nutrition: requirement for IgA in murine nasotracheal anti-influenza immunity

Secretory IgA (SIgA) is the primary mucosal Ig and has been shown to mediate nasotracheal (NT) mucosal immunity in normal immune BALB/c mice. This finding has been challenged by a report of NT immunity without IgA in knockout mice, suggesting that IgA may not be necessary for the protection of mucosal surfaces. Although other protective mechanisms may become active in the congenital absence of SIgA, these mechanisms are not the primary means of protection in normal mice. In this paper we show that feeding chemically defined total parenteral nutrition (TPN) to genetically normal, immune ICR mice by the i.v. route results in loss of nasal anti-influenza immunity and a significant drop in influenza-specific SIgA in the upper respiratory tract compared with chow-fed mice (p < 0.005), while the serum influenza-specific IgG titer is unaffected. Loss of upper respiratory tract mucosal immunity is not related to serum Ab, because 10 of 13 TPN-fed mice shed virus into their nasal secretions despite adequate serum anti-influenza IgG titers. The number of IgG Ab-secreting cells in the nasal passages and spleens of TPN-fed mice was unaffected, while both the number and the percentage of splenic IgA-secreting cells were decreased relative to those in chow-fed animals. The loss of immunity is due to the route of nutrition, not the composition of the diet, because TPN solution fed orally via gastrostomy instead of i.v. maintains NT anti-influenza mucosal immunity. We hypothesize that delivery of nutrition via the gut triggers the release of gastrointestinal neuropeptides necessary for maintenance of the mucosal immune system.

Modulation of organ ICAM-1 expression during IV-TPN with glutamine and bombesin

The gut primes neutrophils (PMNs) during injury, which can then induce distant organ damage after a second insult. ICAM-1 is an important adhesion molecule in PMN attachment to the vascular endothelium. Parenteral nutrition (TPN) decreases gut levels of interleukin (IL)-4 and IL-10, two cytokines that are normal inhibitors of ICAM-1 expression. TPN also increases gut ICAM-1 expression and PMN accumulation. Since glutamine (GLN) and bombesin (BBS) prevent TPN-associated impairment of mucosal immunity, we hypothesized that GLN and BBS would modulate organ ICAM-1 expression in association with normalization of IL-4 and IL-10 levels. Forty-four mice were fed chow, TPN, or GLN-TPN (isonitrogenous 2% GLN-enriched TPN). After 5 days of diets, ICAM-1 expression was quantified in organs using the dual radiolabeled monoclonal antibody technique. In the next experiment, 29 mice were fed chow, TPN, or BBS-TPN (BBS 15 microg/kg TID) for 5 days to measure organ ICAM-1 expression. Total IL-4 and IL-10 levels were measured with ELISA from intestinal homogenates of another set of 52 mice fed chow, TPN, GLN-TPN, or BBS-TPN. TPN significantly increased ICAM-1 expression in the lung, kidney, and intestine compared with chow mice. GLN-TPN decreased intestinal, but not lung, ICAM-1 expression, while BBS-TPN reduced pulmonary, but not gut, ICAM-1 levels. GLN- and BBS-TPN returned gut IL-4 levels to normal, but failed to increase IL-10 levels. GLN and BBS had different effects on organ ICAM-1 expression induced by lack of enteral nutrition. Mechanisms other than recovery of IL-4 alone may be responsible for gut ICAM-1 expression.

Cytokine-modulated inhibition of neutrophil apoptosis at local site augments exudative neutrophil functions and reflects inflammatory response after surgery

BACKGROUND

The fate of exudative polymorphonuclear neutrophils (PMNs) at the local site after surgery is not well understood. We evaluated the fate and functions of exudative PMNs at the local site in patients who were undergoing major surgery. We also investigated the relation between PMN apoptosis and cytokine levels at the local site during the postoperative period.

METHODS

Exudative PMNs were isolated from 11 patients during the postoperative period. Apoptosis, reactive oxygen intermediates (ROI) production, CD16, and tumor necrosis factor receptor expression of the PMNs were determined by flow cytometry. Cytokine levels in the drainage fluid were measured.

RESULTS

Exudative PMN apoptosis was markedly inhibited on postoperative day 1 and then increased in a time-dependent manner. IL-6 and granulocyte macrophage colony-stimulating factor were significant factors to inhibit exudative PMN apoptosis; tumor necrosis factor-alpha and IL-10 were the factors to increase apoptosis. ROI production and CD16 expression of exudative PMNs were augmented when PMN apoptosis was inhibited in the early postoperative period.

CONCLUSIONS

Exudative PMN apoptosis was inhibited after surgery; PMN function was augmented after surgery. Cytokines at the local site may modulate exudative PMN apoptosis. Exudative PMN apoptosis reflected the inflammatory response after surgery. Understanding the mechanisms of PMN apoptosis and its pathophysiologic significance at local inflammatory sites in vivo may help in the design of more rational treatments.

Increased expression of intestinal P-selectin and pulmonary E-selectin during intravenous total parenteral nutrition

HYPOTHESIS

Intravenous total parenteral nutrition (TPN) induces intestinal polymorphonuclear neutrophil recruitment with increased intestinal intercellular adhesion molecule-1 expression. While intercellular adhesion molecule-1 causes firm adhesion of leukocytes to the endothelial cells, P- and E-selectin mediate leukocyte recruitment via rolling. Therefore, manipulation of nutrition may also affect P- and E-selectin expression in organs.

DESIGN

Prospective randomized experimental trials.

SETTING

Laboratory.

MATERIALS

Male mice.

INTERVENTIONS

Fifty-three mice were randomized to chow, intravenous TPN, or intragastric TPN.

MAIN OUTCOME MEASURES

After 5 days of diet, mice were administered iodine 125-labeled anti-P-selectin antibody (or iodine 125-labeled anti-E-selectin antibody) and iodine 131-labeled nonbinding antibody to quantify P-selectin (or E-selectin) expression in organs (lung, liver, kidney, small intestine, colon, stomach, pancreas, mesentery, heart, and skeletal muscle).

RESULTS

P-selectin in small intestine, colon, stomach, and pancreas in the intravenous TPN group increased significantly as compared with the chow and the intragastric TPN groups. E-selectin expression was up-regulated after intravenous TPN in the lung but not in other sites.

CONCLUSIONS

In a time frame (5 days) when intercellular adhesion molecule-1 expression and neutrophil recruitment are increased, intestinal expression of P-selectin remains up-regulated. Early lung inflammatory changes are reflected by increases in E-selectin. This change may reflect early pulmonary dysfunction with intravenous TPN, but its significance requires further study.

Malnutrition impairs CD11b/CD18 expression on circulating polymorphonuclear neutrophils and subsequent exudation into inflammatory sites in the early phase of glycogen-induced murine peritonitis

BACKGROUND

The effects of malnutrition on polymorphonuclear neutrophil (PMN) exudation are not well understood. The purpose of this study was to examine the effects of short-term dietary restriction on adhesion molecule expression on circulating PMNs and PMN exudation into the inflamed site in a glycogen-induced peritonitis model.

METHODS

Twelve mice were randomly assigned to one of two groups. The ad libitum and diet-restricted groups received mouse chow ad libitum (estimated consumption: 132 g/kg per day) and 33 g/kg per day, respectively, for 7 days. Then, 2 mL of a 1% glycogen solution was intraperitoneally administered to all mice. After 4 hours, the animals were killed. Whole blood was drawn by cardiac puncture. Peritoneal exudative cells were harvested by lavaging the peritoneal cavity. Expressions of CD11b, CD18, and CD62L were measured by flow cytometry.

RESULTS

Dietary restriction did not affect the numbers of circulating leukocytes, PMNs, or monocytes. However, CD11b and CD18 expressions on circulating PMNs were significantly lower in the diet-restricted than in the ad libitum group. In contrast, CD62L expression on circulating PMNs was not affected by dietary restriction. The number of exudative PMNs was significantly lower in the diet-restricted group than in the ad libitum group. The expressions of CD11b, CD18 and CD62L on exudative PMNs were unaffected by dietary restriction. There was a significant positive correlation between exudative PMN numbers and CD18 expression on circulating PMNs.

CONCLUSIONS

Severe dietary restriction in our murine model decreased beta2 integrin expression on circulating PMNs and inhibited PMN exudation into inflamed sites in the early phase of inflammation. These events may increase susceptibility to bacterial infection. Nutritional replenishment may improve host defense in part by enhancing PMN adhesion molecule expression.

Individual neuropeptides regulate gut-associated lymphoid tissue integrity, intestinal immunoglobulin A levels, and respiratory antibacterial immunity

BACKGROUND

Total parenteral nutrition (TPN) leads to atrophy of the gut-associated lymphoid tissue (GALT) and a significant decrease in intestinal immunoglobulin A (IgA) levels, a major constituent of mucosal immunity. Bombesin (BBS) prevents TPN-induced GALT atrophy and maintains intestinal IgA levels. BBS, a neuropeptide analogous to gastrin-releasing peptide in humans, stimulates the release of other gut neuropeptides including cholecystokinin (CCK), gastrin, and neurotensin (NT). This study investigates the ability of CCK, gastrin, or NT to individually prevent TPN-induced GALT atrophy and preserve respiratory immunity.

METHODS

Experiment 1: Male mice were randomly assigned to receive chow, TPN, TPN plus CCK, TPN plus gastrin, or TPN plus NT. After 5 days of feeding, Peyer's patches (PP) from the proximal and distal small bowel were harvested and analyzed for cell yields. PP cells were also analyzed for GALT cell type. Small bowel IgA levels were measured by enzyme-linked immunosorbent assay (ELISA). Experiment 2: Mice were randomly assigned to receive either liposomes containing Pseudomonas antigen or liposomes without antigen. After 10 days, mice were randomly assigned to the same five treatment groups, fed for 5 days, and then given intratracheal Pseudomonas. Mortality was assessed after 48 hours.

RESULTS

Experiment 1: GALT cell reductions due to IV-TPN were greater in the distal than proximal small bowel. All three neuropeptides prevented most TPN-induced GALT atrophy due mainly to the maintenance of the B-cell and T-cell populations in the PP of the distal bowel. Intestinal IgA levels were significantly higher in the animals treated with neuropeptides than animals treated with TPN only; however, these IgA levels were not maintained at levels observed in chow-fed animals. Experiment 2: Immunization resulted in significantly lower mortality in animals fed chow, TPN plus CCK, and TPN plus gastrin. TPN alone and TPN plus NT resulted in loss of immunity and mortality rate at comparable levels to unimmunized animals.

CONCLUSIONS

Supplementation of IV-TPN with CCK, gastrin, and NT prevents GALT atrophy, primarily in the distal bowel. Intestinal IgA levels improve but not to normal levels. CCK and gastrin reversed IV-TPN-induced effects on antibacterial pneumonia in immunized animals while NT did not.

Glutamine-enriched total parenteral nutrition maintains intestinal interleukin-4 and mucosal immunoglobulin A levels

BACKGROUND

Total parenteral nutrition (TPN) prevents progressive malnutrition but fails to maintain intestinal gut-associated lymphoid tissue (GALT) or established respiratory antiviral or antibacterial mucosal immunity. Our previous work demonstrated that decreases in intestinal immunoglobulin A (IgA) were associated with decreases in Th2-type IgA-stimulating cytokines, interleukin (IL)-4 and IL-10. Because glutamine supplementation of TPN partially preserves respiratory defenses and normalizes GALT, we investigated the ability of parenteral glutamine to normalize respiratory and intestinal IgA levels and measured Th2 cytokines in intestinal homogenates.

METHODS

Animals were cannulated and randomly assigned to receive chow (n = 17), TPN (n = 18), or an isonitrogenous, isocaloric TPN solution formulated by removing the appropriate amount of amino acids and replacing them with 2% glutamine (n = 18) for 5 days. Respiratory tract and intestinal washings were obtained for IgA and the intestine homogenized and analyzed for IL-4 and IL-10.

RESULTS

TPN decreased intestinal and respiratory IgA in association with decreases in intestinal IL-4 and IL-10 compared with chow-fed animals. Glutamine significantly improved respiratory and intestinal IgA levels, significantly improved IL-4 compared with TPN animals, and maintained IL-10 levels midway between chow-fed and TPN animals.

CONCLUSIONS

Glutamine-enriched TPN preserved both extraintestinal and intestinal IgA levels and had a normalizing effect on Th2-type IgA-stimulating cytokines.

Relative effects of glucose and glutamine on reactive oxygen intermediate production by neutrophils

The energy source for neutrophils (PMNs) has long been believed to be glucose. However, it has been shown recently that PMNs use glutamine as well as glucose. Nevertheless, the comparative effects of glucose and glutamine on PMN function remain to be clarified. This study investigated the relative effects of glucose and glutamine on reactive oxygen intermediate (ROI) production by PMNs. In experiment 1, PMNs (1 x 10(6)/mL) isolated from healthy volunteers were incubated in RPMI 1640 medium containing neither glucose nor glutamine for 4, 12, 18, and 24 h at 37 degrees C. The medium was supplemented with 0 or 200 mg/dL (0 or 11 mM, respectively) glucose and glutamine (0, 0.5, 1, or 2 mM). PMN cell death was assessed on the basis of hypodiploid DNA by flow cytometry using propidium iodide DNA staining. ROI production by PMNs was determined by flow cytometry using dihydrorhodamine 123. In experiment 2, isolated PMNs were cultured in RPMI 1640 medium containing neither glucose nor glutamine. The medium was supplemented with glucose (0 or 11 mM) and a competitive inhibitor of glycolysis, 2-deoxy-D-glucose (2-DG; 0 or 20 mM). Each medium was supplemented with glutamine (0, 0.5, 1, or 2 mM) and incubated for 12 h at 37 degrees C. Then, ROI production by PMNs was measured. PMN cell death was not affected by glucose or glutamine in this experiment. In contrast, ROI production by PMNs was greater at 11 mM glucose than at 0 mM glucose at all incubation times studied. At 11 mM glucose, supplemental glutamine enhanced PMN ROI production after 18 and 24 h culture. In contrast, at 0 mM glucose, glutamine augmented ROI production by PMNs after 12 h as well as with 18 and 24 h incubations. PMN ROI production after 12 h culture was significantly greater at 11 mM glucose without 2-DG than at both 11 and 0 mM glucose with addition of 2-DG. In addition, supplemental glutamine enhanced ROI production by PMNs when 2-DG was added at 11 and 0 mM glucose. Glucose is essential for PMN ROI production. Under conditions of glucose depletion in vitro, glutamine is of importance in ROI production by PMNs, whereas the enhancing effect of glutamine on PMN ROI production is minor compared to that of glucose.

ESR study on the antioxidant activity of TAK-218 in biological model membranes

TAK-218 has a 2,3-dihydrobenzofuran-5-amine (coumaran) structure which resembles alpha-tocopherol, and is a promising candidate as an agent for central nervous system (CNS) trauma and ischemia. The radical scavenging activity of TAK-218 was studied using electron spin resonance (ESR) spectroscopy. TAK-218 exhibited a more potent scavenging activity towards the hydroxyl radical than did the well-known hydroxyl radical scavengers, mannitol and dimethylsulfoxide. Towards the superoxide radical, TAK-218 showed equal potency to glutathione. TAK-218 reacted rapidly with stable radicals, such as galvinoxyl and 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), and gave the quinone as a two-electron oxidized product in analogy with alpha-tocopherol. To exhibit an excellent antioxidative activity in living systems, the compounds should not only have the intrinsic radical scavenging activity but also good distribution in the biological lipid-bilayer membrane. To examine the antioxidant activity of TAK-218, the inhibition of lipid peroxidation by alpha-tocopherol and TAK-218 in liposomal membranes was studied using an ESR spin-label technique. Both alpha-tocopherol and TAK-218 completely inhibited lipid peroxidation by radicals generated in an aqueous layer using a water-soluble radical initiator, 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH). At a high incubation temperature (45 degrees C), alpha-tocopherol scavenged radicals more effectively than TAK-218 on the surface of the membrane, while TAK-218 scavenged radicals more effectively in the interior of the membrane. The difference between TAK-218 and alpha-tocopherol for radical scavenging in the membrane system derives from the different distribution pattern of these compounds. TAK-218 can penetrate the membrane freely and can scavenge the radical in the membrane interior. Furthermore, TAK-218 was shown to inhibit lipid peroxidation initiated by a lipid soluble radical initiator, 2,2'-azobis-(2,4-dimethylvaleronitrile) (AMVN), in a membrane more effectively than alpha-tocopherol.

Supplemental glutamine augments phagocytosis and reactive oxygen intermediate production by neutrophils and monocytes from postoperative patients in vitro

The energy substrate for neutrophils has been believed to be glucose. However, a recent investigation has demonstrated that neutrophils use glutamine (Gln) as well as glucose. Nevertheless, little is known about the effects of Gln on neutrophil function. Thus, this study was designed to investigate the effects of Gln on phagocytosis and reactive oxygen intermediate (ROI) production by neutrophils from postoperative patients in vitro. Eleven patients who had undergone major gastrointestinal surgery were randomly selected. Peripheral blood was drawn before surgery and on postoperative days (PODs) 1, 3, and 7. The blood was washed with medium to remove plasma. Washed whole blood was incubated in RPMI 1640 medium containing neither Gln nor glucose for 24 h at 37 degrees C. The medium was supplemented with Gln at a concentration of 0, 500, 1000, or 2000 microM. Whole blood was then assessed for phagocytosis by flow cytometry using fluorescent beads. ROI production by phagocytes was measured by flow cytometry using dihydrorhodamine 123. In each assay, the neutrophil population was gated and analyzed. Serum amino acids were also measured. Postoperative serum Gln level decreased significantly until POD 7. Phagocytosis by neutrophils on PODs 3 and 7 was significantly greater at 2000 microM Gln than at other Gln concentrations. Neutrophil ROI production was significantly greater at 2000 microM Gln than at 0 microM Gln at each time point. In conclusion, supplemental Gln enhances both phagocytosis and ROI production by neutrophils from postoperative patients in vitro.

Ratio of bacteria to polymorphonuclear neutrophils (PMNs) determines PMN fate

This study was designed to investigate how live Escherichia coli influence the fate of polymorphonuclear neutrophils (PMNs) in vitro. PMNs from 10 healthy volunteers were cocultured with or without live E. coli at different ratios. Heat-killed E. coli (Hk) were also added to PMNs at a ratio of 1:10. The PMNs were then analyzed by flow cytometry for cell death, reactive oxygen intermediates (ROI) production, and CD16 expression. Morphologic features were also assessed. PMN apoptosis was confirmed by DNA gel electrophoresis. Low doses of E. coli (PMN:E. coli ratios of 1:0.01 and 1:0.1) inhibited PMN apoptosis. In contrast, a high dose of E. coli (PMN:E. coli ratio of 1:10) increased PMN necrosis. ROI production was significantly greater at PMN:E. coli ratios of 1:10 and 1:10 (Hk) than at ratios of 1:0.01 and 1:0.1, or in PMNs cultured alone after a 15 or 30 minute coculture. CD16 expressions were significantly lower in PMNs cocultured with E. coli than in those cultured alone after a 4 or 12-h coculture. Tumor necrosis factor-alpha, interleukin (IL)-1beta and IL-6 levels in cell-free supernatants were also measured. The mean percentages of apoptosis at PMN:E. coli ratios of 1:0.01 and 1:10 (Hk), and in PMNs cultured alone after a 12-h coculture showed significant inverse correlations with these cytokine levels in cell-free supernatants at 12 h. Our results demonstrate that low doses of live E. coli inhibits predominantly PMN apoptosis, whereas a high dose of E. coli increases necrosis. Augmented PMN bactericidal function, via inhibition of PMN cell death, may be beneficial for host defense against bacterial infection and/or sepsis.

Route of nutrition influences intercellular adhesion molecule-1 expression and neutrophil accumulation in intestine

HYPOTHESIS

The levels of intestinal interleukin 10 and interleukin 4, inhibitors of intercellular adhesion molecule-1 (ICAM-1) expression, decline with total parenteral nutrition (TPN). These cytokine changes induced by lack of enteral nutrition may increase ICAM-1 expression, resulting in polymorphonuclear neutrophil accumulation in intestine.

DESIGN

Prospective randomized experimental trials.

SETTING

Laboratory.

MATERIALS

Male mice.

INTERVENTIONS

Sixty-three mice were randomized to chow, intravenous TPN, or intragastric TPN.

MAIN OUTCOME MEASURES

Experiment 1: After diet manipulation, iodine 125-labeled anti-ICAM-1 antibody and iodine 131-labeled nonbinding antibody were injected to quantify ICAM-1 expression on endothelial cells in the lung, liver, kidney, and small intestine. Measurement of myeloperoxidase was used to quantify polymorphonuclear neutrophil accumulation in the organs. Experiment 2: Intestine was harvested for both ICAM-1 and myeloperoxidase levels after chow refeeding of mice in the intravenous TPN group.

RESULTS

In experiment 1, uninjured mice fed intravenous TPN showed significantly increased intestinal ICAM-1 expression and polymorphonuclear neutrophil accumulation with no significant changes in the lung, liver, or kidney. No changes occurred in mice fed chow or intragastric TPN. In experiment 2, reinstitution of enteral feeding returned intestinal ICAM-1 and myeloperoxidase levels to normal.

CONCLUSION

Gut changes associated with lack of enteral feeding induce endothelial changes and an immunologic response, which may influence subsequent responses to injury.

Prophylactic treatment with growth hormone and insulin-like growth factor I improve systemic bacterial clearance and survival in a murine model of burn-induced gut-derived sepsis

The purpose of this investigation was to evaluate the effects of GH and IGF-I administration in a murine model of burn-induced gut-derived sepsis. BALB/C mice were treated with 4.8 mg/kg/day of GH, 24 mg/kg/day of IGF-I or saline for 4 days. They were then administered 10(10) E. coli by gavage and subjected to 20% full thickness flame burn. All mice received allogeneic blood transfusion 5 days before burn injury to induce mild immunosuppression. Seventy-three mice were observed for survival and 51 mice were sacrificed at 4 and 20 h postburn. Blood, mesenteric lymph nodes (MLN), spleen and liver were harvested aseptically, and viable bacterial counts in the organs were determined. The small intestine was harvested for the evaluation of villus height and mitoses in the crypts. GH and IGF-I groups showed a significantly better survival than the control group. GH and IGF-I groups had significantly greater villus height and mitoses/crypt than the control group. Translocation of bacteria was not significantly different among groups, however, the relation between the numbers of viable bacteria in MLN and blood suggests that both GH and IGF-I reduced systemic spread of translocated bacteria. It is concluded that GH and IGF-I had positive effects on outcome in this model of burn-induced gut-derived sepsis. It appears that GH and IGF-I may have immune-enhancing effects and that administration of these agents may be useful for burn injury.

Concomitant increase in neutrophil adhesion to inflammatory peritoneum and remote organs during peritonitis

BACKGROUND

Neutrophils contribute to the host defense mechanism, but they can cause remote organ injury in peritonitis. The purpose of this study was to examine neutrophil adhesion to the peritoneum and remote organs simultaneously in peritonitis using a fluorescence microscopic method.

STUDY DESIGN

Experiment 1: Sprague-Dawley rats (n = 16) were injected intraperitoneally (ip) with saline solution or 10(5), 10(7), or 10(9) Escherichia coli. Five hours after challenge, 1 x 10(6) fluorescein-labeled neutrophils were infused. Two minutes after neutrophil injection, five peritoneal samples (the greater omentum, mesentery, parietal peritoneum, colon, and ileum), both lungs, the liver, and the right kidney were harvested for counting of labeled neutrophils under epifluorescent microscopy. Lung myeloperoxidase (MPO) activity was also determined. Experiment 2: Rats (n = 23) were given 10(9) E. coli ip. Before challenge (0 h) or at 1, 5, or 10 h after challenge, labeled neutrophils were infused. Then, the labeled neutrophil numbers in organs and lung MPO activities were assessed as described for Experiment 1. Hemodynamic and arterial blood gas data were also obtained in another set of rats before and at 1, 5, 8 and 10 h after 10(9) E. coli ip challenge.

RESULTS

Experiment 1: The labeled neutrophil numbers in the peritoneum, lungs, and kidney showed significant positive correlations with the injected bacterial numbers. Lung MPO also positively correlated with E. coli number and labeled neutrophil number in the lungs. Experiment 2: Labeled neutrophil numbers in the peritoneum and kidney peaked at 5 h. The pulmonary labeled neutrophil number rose, reaching a plateau at 5 h. No remarkable change was observed in the hepatic labeled neutrophil number. There was a positive correlation between lung MPO activity and pulmonary labeled neutrophil number. Hemodynamic and blood gas data reflected a hyperdynamic state.

CONCLUSIONS

Concomitant dose-dependent increases in neutrophil adhesion in the peritoneum, lungs, and kidney were observed in this peritonitis model. Increased neutrophil adhesion was transient in the peritoneum and kidney but persistent in the lungs. Strategies modulating neutrophil adhesion in organs are anticipated to be useful for the treatment of peritonitis.

Growth hormone inhibits apoptosis and up-regulates reactive oxygen intermediates production by human polymorphonuclear neutrophils

BACKGROUND

Growth hormone (GH) regulates the immune and metabolic systems; however, the effects of GH on the functions and cell death of polymorphonuclear neutrophils (PMNs) are not well understood. Therefore, this study was designed to investigate the effects of GH on PMN apoptosis, reactive oxygen intermediates (ROI) production, CD16, and Fas expression. We also investigated the effects of GH on the functions of other circulating leukocytes (ie, monocytes and lymphocytes).

METHODS

Venous blood was collected from healthy volunteers. Whole blood was washed and pretreated with GH (0 or 100 ng/mL) for 3 hours and then cultured for 0, 4, or 12 hours. PMNs in washed whole blood were analyzed by flow cytometry for cell death, phorbol myristate acetate-stimulated ROI production, CD16, and Fas expression at each time point. Morphologic features also were assessed. PMN apoptosis was confirmed by chromatin staining and DNA gel electrophoresis.

RESULTS

GH inhibited PMN apoptosis at 12 hours of culture. GH enhanced ROI production by PMNs and monocytes throughout the 12-hour culture but had no effects on CD16 expression on PMNs. Furthermore, GH decreased Fas expression on PMNs at 4 hours of culture. However, there were no effects of GH on apoptosis of monocytes or lymphocytes for the duration of this experiment.

CONCLUSIONS

GH pretreatment down-regulates Fas expression on PMNs, inhibits apoptosis, and up-regulates ROI production. GH pretreatment also increases monocyte ROI production. Although activated PMNs have potentially harmful aspects, our results suggest that GH may improve host defense, mainly through enhancement of the PMN functional life span.

Growth hormone and insulin-like growth factor I augment bactericidal capacity of human polymorphonuclear neutrophils

Effects of growth hormone (GH) and insulin-like growth factor (IGF)-I on bactericidal capacity of human polymorphonuclear neutrophils (PMNs) were investigated. Venous blood was collected from healthy volunteers. In Experiment 1, PMNs were isolated, incubated with GH or IGF-I, and cocultured with Escherichia coli. E. coli-killing capacity, viability, and CD11b and CD16 expressions of PMNs were then assessed. Both GH and IGF-I enhanced E. coli killing by PMNs. GH preserved PMN viability during E. coli killing, whereas IGF-I enhanced PMN CD11b expression before coculture with E. coli. In Experiment 2, whole blood was washed and incubated with GH or IGF-I. PMNs in washed whole blood were then analyzed for phorbol myristate acetate (PMA)-stimulated CD11b, CD35, and CD16 expressions and production of reactive oxygen intermediates (ROI), as well as phagocytosis with/without anti-CD11b antibody. IGF-I enhanced PMN expressions of CD11b and CD35, but not CD16, stimulated with PMA. Both hormones enhanced phagocytosis, which was abrogated by anti-CD11b antibody, and intracellular ROI production by PMNs. These results indicate that both GH and IGF-I augment human PMN bactericidal capacity, via increased phagocytosis and intracellular ROI production. Preservation of PMN viability by GH and enhanced complement receptor expression by IGF-I may also be associated with augmented PMN bactericidal capacity. Although PMN activation has potentially harmful aspects, these results encourage additional studies to confirm the clinical relevance of exogenous GH or IGF-I for the prevention or management of septic complications in perioperative or critically ill patients especially with low circulating GH and/or IGF-I levels.

Nitric oxide donor decreases neutrophil adhesion in both lung and peritoneum during peritonitis

BACKGROUND

As nitric oxide (NO) is an antiadhesive molecule, exogenous NO may modulate neutrophil adhesion in organs. This study was designed to examine the effects of the NO donor SNAP (S-nitroso-acetyl penicillamine) on neutrophil adhesion at the inflammatory site and in remote organs, in peritonitis using a fluorescent microscopic method.

MATERIALS AND METHODS

In experiment 1, rats (n = 12) were given saline or 10 micrograms/kg of SNAP intravenously followed by continuous infusion of saline, or of 2, 20, or 200 micrograms/kg/h SNAP until sacrifice. Ten minutes after injection of saline or SNAP, 10(7) Escherichia coli were injected into the peritoneal cavity. Five hours after challenge, 10(6) fluorescein-labeled neutrophils were infused. Peritoneal samples, lungs, liver, and kidney were harvested for counting of labeled neutrophils under epifluorescent microscopy. In experiment 2, rats (n = 25) were treated with saline or 10 micrograms/kg of SNAP intravenously and infused with saline or 20 micrograms/kg/h SNAP; E. coli was injected as in experiment 1. Before or 5 h after challenge, hemodynamic data were obtained. Then, labeled neutrophils were infused for counting of neutrophil numbers in organs. Arterial blood gas data and the circulating neutrophil number were also determined.

RESULTS

Experiment 1. Twenty and 200 micrograms/kg/h SNAP infusions tended to reduce labeled neutrophil numbers in lungs, while all three SNAP doses decreased the peritoneal labeled neutrophil numbers.

RESULTS

Experiment 2. Five hours after bacterial injection, SNAP infusion simultaneously decreased both pulmonary and peritoneal labeled neutrophil numbers. SNAP had no effect on hemodynamic and blood gas data, or on circulating neutrophil numbers.

CONCLUSION

NO donors may be useful for preventing neutrophil-associated lung injury, but should be used with caution in light of the possible adverse effects on host defense in the peritoneal cavity.

Effects of growth hormone and insulin-like growth factor I on opsonin receptor expression on local and systemic phagocytes in a lethal peritonitis model

OBJECTIVE

To investigate the effects of pretreatment with growth hormone (GH) and insulin-like growth factor I (IGF-I) on phagocyte exudation and bacterial clearance, focusing on CD11b and CD32/CD16 expression on local and systemic phagocytes, in a lethal peritonitis model.

DESIGN

Prospective randomized experimental study.

SETTING

Research laboratory in a university hospital.

SUBJECTS

Balb/c mice (n = 21).

INTERVENTIONS

Mice were challenged intraperitoneally with 1 x 10(8) Escherichia coli, after 6 days of pretreatment with saline (control), GH (4.8 mg/kg/day), or IGF-I (24 mg/kg/day). Samples were harvested at 4 hrs after the challenge.

MEASUREMENTS AND MAIN RESULTS

Viable bacterial counts in peritoneal lavage fluid (PLF) and blood were determined. Peritoneal exudative cells and peripheral blood leukocytes were counted and analyzed for receptor expressions by flow cytometry. GH reduced viable bacterial counts in PLF, as compared with the saline control. GH (three-fold) and IGF-I (two-fold) increased the number of peritoneal exudative neutrophils (PENs), as compared with the saline control. The number of PENs showed an inverse correlation with PLF viable bacterial counts. By contrast, there were no differences in peripheral blood neutrophil (PN) counts among the three groups, nor was there a correlation between PN and PEN counts. CD11b expression was greater on PENs than on PNs in all three groups. CD11b expression on PNs did not differ among the three groups. However, GH increased CD11b expression on PENs, as compared with saline and IGF-I, and this expression showed a positive correlation with PEN numbers and an inverse correlation with PLF viable bacterial counts. CD11b expression on peritoneal macrophages and peripheral blood monocytes did not differ among the three groups. There were no differences in phagocyte CD32/CD16 expression among the three groups.

CONCLUSIONS

GH pretreatment enhanced CD11b expression on PENs, but not PNs, possibly in association with enhanced neutrophil recruitment, phagocytosis, and bacterial elimination by PENs, without activation of PNs. GH prophylaxis may be useful for reducing the frequency rate and severity of septic complications, via modulation of CD11b expression on local and systemic neutrophils.

Influences of type and duration of antimicrobial prophylaxis on an outbreak of methicillin-resistant Staphylococcus aureus and on the incidence of wound infection

OBJECTIVE

To clarify how antibiotic prophylaxis influenced an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) and postoperative infection.

DESIGN

Retrospective review.

SETTING

University-affiliated teaching hospital.

PATIENTS

All patients (n=1824) undergoing subtotal esophagectomy, gastrectomy, or colorectal surgery during the period 1982 through 1995.

MAIN OUTCOME MEASURES

Type, timing, and duration of prophylactic antibiotics. Postoperative infection by the Centers for Disease Control and Prevention definition and the organisms isolated.

RESULTS

Third-generation cephalosporins were frequently administered for prophylaxis during the period 1982 through 1990. The rate of isolates of MRSA from the infected site increased, peaking in 1988 to 1990. Since 1991 to 1992, along with a marked decrease in third-generation cephalosporin use, the rates of MRSA isolated have declined dramatically. The timing of administration changed from postoperative to intraoperative. Although the duration was gradually decreased, coverage was still provided until about the fifth postoperative day, even during 1993 to 1995. Prolonged coverage did not reduce the rate of superficial incisional or organ/space surgical site infection or that of pneumonia.

CONCLUSIONS

Overuse of third-generation cephalosporins for long periods caused an MRSA outbreak. Long-term prophylaxis did not lower infection rates. The briefest possible prophylaxis with first- or second-generation cephalosporins should be used in general surgery.

Glutamine-enhanced bacterial killing by neutrophils from postoperative patients

Neutrophils play an important role in host defense by phagocytosing and destroying invading bacteria. A recent investigation revealed that glutamine (Gln) augmented the in vitro bactericidal activity of neutrophils from burn patients. However, it is unclear whether Gln enhances the function of neutrophils in postoperative patients. This study was designed to investigate the effect of Gln on the in vitro Escherichia coli-killing activity of neutrophils from postoperative patients. Nine randomly selected patients were included in this study. On the morning of the first postoperative day, blood was drawn and neutrophils were isolated. Eight healthy volunteers served as controls. E. coli was opsonized with pooled normal serum. Neutrophils (5 x 10(6)), together with opsonized E. coli (5 x 10(5)), were incubated for 2 h at 37 degrees C in Hanks' balanced salt solution supplemented with 0, 100, 500, or 1000 nmol/mL of Gln. The bactericidal function of neutrophils was determined by counting the number of viable bacteria. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-8, and granulocyte elastase levels in the cell culture supernatant were measured. Plasma C-reactive protein (CRP), cortisol, and amino acids were also analyzed. The plasma concentration of Gln was significantly lower in the postoperative patients than in the controls. Following culture with patient neutrophils, the number of viable E. coli decreased by 26% as the in vitro Gln concentration was increased from 500 to 1000 nmol/mL (P < 0.01). We defined the Gln 1000/Gln 500 ratio of the number of viable bacteria as the number of viable E. coli at an in vitro Gln concentration of 1000 nmol/mL divided by the number of viable E. coli at an in vitro Gln concentration of 500 nmol/mL. A positive correlation was thus demonstrated between the plasma Gln level and the Gln 1000/Gln 500 ratio of the number of viable bacteria in the patients (r = 0.69, P = 0.04). This finding indicated that as plasma Gln fell, there was an enhancement of neutrophil E. coli-killing activity by neutrophils in in vitro tests when the Gln concentration was increased from 500 to 1000 nmol/mL. Gln supplementation caused no appreciable changes in TNF-alpha, IL-1 beta, IL-8, or granulocyte elastase levels in cell culture supernatants. A negative correlation was recognized between the patient plasma Gln level and the Gln 1000/Gln 500 ratio of the cell culture supernatant IL-8 level (r = -0.73, P = 0.025). In conclusion, Gln supplementation enhanced the in vitro bactericidal function of neutrophils from postoperative patients.

Glutamine-enriched enteral diet enhances bacterial clearance in protected bacterial peritonitis, regardless of glutamine form

BACKGROUND

The effects of glutamine (Gln)-enriched enteral diets on bacterial clearance were investigated in a rat protracted peritonitis model. The effects of the Gln form, peptide-based vs free amino acid-based, were also compared.

METHODS

Twenty-three rats underwent gastrostomy. An osmotic pump was implanted in the peritoneal cavity. The rats received a continuous intragastric infusion of one of three diets: Gln-depleted (Gln 0), Gln-enriched with the Gln in free amino acid form (Gln F), or Gln-enriched with the Gln in oligopeptide form (Gln P). The three formulas were isocaloric and isonitrogenous. The pumps delivered a continuous infusion of Escherichia coli, starting at 48 hours after implantation, for 24 hours. Then, the animals were killed.

RESULTS

Bacterial numbers in peritoneal lavaged fluid (PLF) and the liver were significantly lower in the Gln P and Gln F groups than in the Gln 0 group. The bacterial number in PLF correlated with that in the liver. Neither the number nor the population of peritoneal exudative cells differed among groups. Plasma levels of proline, alanine and citrulline were significantly higher in the Gln P and Gln F groups than in the Gln 0 group. Both Gln supplemented groups showed significantly greater villous height, crypt depth, and numbers of mitoses per crypt in the small intestine than the Gln 0 group.

CONCLUSIONS

Supplemental Gln enhances peritoneal and hepatic bacterial clearance, regardless of Gln form. Gln-enriched may be more beneficial than Gln-depleted enteral diets in peritonitis.

Insulin-like growth factor 1 has beneficial effects, whereas growth hormone has limited effects on postoperative protein metabolism, gut integrity, and splenic weight in rats with chronic mild liver injury

BACKGROUND

Both growth hormone (GH) and insulin-like growth factor 1 (IGF-1) improve protein metabolism after surgical insult in subjects without liver disease. However, these effects in chronic liver injury, in which the GH-IGF-1 axis is impaired, have not been investigated. We examined the anabolic effects of GH and IGF-1 after gastrectomy in rats with chronic mild liver injury.

METHODS

Rats with chronic mild liver injury induced by thioacetamide were used. After gastrectomy, the rats were randomized into vehicle control, GH, and IGF-1 groups. In the latter two groups, 0.8 IU/kg/d of GH or 4 mg/kg/d of IGF-1 was infused for 72 hours. Anabolic effects were assessed by body weight change, 3-methylhistidine (3-MH) excretion, nitrogen excretion, and whole-body protein turnover. Organ weights, plasma levels of glucose, insulin, and IGF-1, tissue IGF-1 levels, hepatic messenger RNA (mRNA) content, and intestinal structure were also determined.

RESULTS

Both GH and IGF-1 decreased nitrogen excretion. IGF-1, but not GH, increased postoperative body weight, whole-body protein turnover, and splenic weight. IGF-1 reduced atrophy of the intestinal mucosa. GH treatment increased hepatic IGF-1-mRNA and the plasma IGF-1 level, whereas IGF-1 treatment increased the plasma IGF-1 level with no change in the hepatic IGF-1-mRNA content. There were no significant differences in plasma glucose or insulin levels among the three groups. Neither GH nor IGF-1 affected the gastrocnemius muscle IGF-1 level.

CONCLUSIONS

IGF-1 has beneficial effects, whereas GH has only limited effects on post-operative protein metabolism, gut integrity, and splenic weight in chronic mild liver injury.

Nitric oxide inhibition decreases neutrophil adhesion at the inflammatory site, while increasing adhesion in remote organs in peritonitis

Nitric oxide (NO) is a regulator of leukocyte adhesion in the microcirculation. This study was designed to examine the effects of a NO synthase inhibitor on neutrophil adhesion in the peritoneum, lung, liver, and kidney in a rat peritonitis model using a fluorescence microscopic method. Sprague-Dawley rats were given normal saline (control) or N omega-nitro-L-arginine methyl ester (L-NAME) at dosages of 10 mg/kg (N10) or 100 mg/kg (N100) (n = 66) intraperitoneally. One hour after pretreatment fluorescein-labeled neutrophils were infused without bacterial challenge (0 hr). Other rats received an injection of 10(7) Escherichia coli into the peritoneal cavity 1 hr after pretreatment. Labeled neutrophils were infused 1 and 5 hr after bacterial challenge. Just 2 min after neutrophil injection, blood samples were obtained and the animals were killed. Five peritoneal samples (omentum, mesentery, parietal peritoneum, colon, and ileum), both lungs, the liver, and the right kidney were harvested for counting of labeled neutrophils under epifluorescent microscopy. Combined plasma nitrite/nitrate levels were determined. In another set of rats (n = 36), an arterial catheter was inserted after L-NAME treatment and bacterial challenge. At 0, 1, 5, and 12 hr after challenge, blood pressure, heart rate, and arterial blood gas data were measured. One hour after E. coli challenge, the number of neutrophils in the peritoneum was significantly lower in both L-NAME-treated groups than in the control group. In contrast, the number of labeled neutrophils in the lungs was significantly higher in the N100 group than in the control group. Neutrophil accumulation in the lungs and peritoneum at 0 and 5 hr and in the liver and kidney at 0, 1, and 5 hr did not differ among groups, nor did combined plasma nitrite/nitrate levels. L-NAME treatment had no influence on either hemodynamic or blood gas data. In conclusion, administration of L-NAME increases neutrophil adhesion in the lung, while decreasing that in the peritoneum. NO plays an important role in neutrophil adhesion at the inflammatory site, as well as in remote organs, during peritonitis. NO inhibition may be detrimental, due to neutrophil sequestration, in this peritonitis model.

5-aminocoumarans: dual inhibitors of lipid peroxidation and dopamine release with protective effects against central nervous system trauma and ischemia

A series of 2,3-dihydro-5-benzofuranamines (5-aminocoumarans) were developed for the treatment of traumatic and ischemic central nervous system (CNS) injury. Compounds within this class were extremely effective inhibitors of lipid peroxidation in vitro and antagonized excitatory behavior coupled with peroxidative injury induced by spinal intrathecal injection of FeCl2 (mouse-FeCl2-it assay) in vivo. Selected compounds were tested for antagonistic activity on methamphetamine (MAP)-induced hypermotility resulting from dopamine release in the mouse brain. Among the compounds synthesized, compound 26n (2,3-dihydro-2,4,6,7-tetramethyl-2-[(4-phenyl-1-piperidinyl) methyl]-5-benzofuranamine) exhibited potent effects in these assays (inhibition of lipid peroxidation, IC50 = 0.07 microM; mouse-FeCl2-it assay, ID50 = 10.4 mg/ kg, po; MAP-induced hypermotility, 98% inhibition, 10 mg/kg, ip). The S-(+)-form of compound 26n dihydrochloride (TAK-218), which has 30 times more potent antagonistic activity on MAP-induced hypermotility than the R-(-)-form, improved more significantly the survival rate in the cerebral ischemia model (rat, 1-3 mg/kg, ip) during the period of 1-14 days after ischemia and decreased functional disorders in the traumatic brain injury model (rat, 0.1-1 mg/kg, ip) 3-14 days after injury. These results imply a role for dopamine in deterioration of CNS function after ischemic and traumatic injury. TAK-218 is a promising compound for the treatment of stroke and CNS trauma and is now under clinical investigation.

Preoperative total parenteral nutrition influences postoperative systemic cytokine responses after colorectal surgery

Previous human studies have investigated the influences of nutritional routes on the serum kinetics of cytokines following intravenous administration of lipopolysaccharide. However, it is unclear whether preoperative nutritional routes influence responses of systemic cytokines in patients after surgery. This study was designed to investigate whether preoperative total parental nutrition (TPN) influences systemic interleukin-6 (IL-6) and interleukin-8 (IL-8) responses in patients following surgery for colorectal cancer. Patients with colorectal cancer received TPN (TPN group, n = 6) or an oral diet (oral group n = 6) for more than 7 d before the operation. Patients in the TPN group received standard TPN. Patients in the oral group received an ordinary hospital diet. Blood samples were collected before the operation, on postoperative day 1 (POD1), POD3, and POD7. Levels of IL-6, IL-8, and C-reactive protein (CRP) in plasma were determined. The characteristics of patients in the TPN and oral groups were comparable. Mean carbohydrate intake was greater (28 versus 19 kCal/kg), and lipid intake was smaller (0 versus 7 kCal/kg) in the TPN group than in the oral group. Plasma CRP levels did not differ between the two groups. Plasma IL-6 and IL-8 levels were marginally higher before the operation and were significantly higher on POD1 in the TPN group than in the oral group. The IL-6 levels showed a positive regression relation with the amounts of blood loss only in the TPN group (P < 0.05, r = 0.881). The slope of the regression line was steeper in the TPN group than in the total enteral nutrition (TEN) group (P < 0.01). In conclusion, routes of nutritional supply have an impact on the production of systemic cytokines after insult. The postoperative systemic IL-6 and IL-8 responses in patients who received standard TPN preoperatively were greater than in patients who received an oral diet. Preoperative nutrition via the enteral route may provide better regulation of cytokine responses after surgery than parenteral nutrition.

Effects of growth hormone and insulin-like growth factor 1 (IGF-1 ) on hepatic IGF-1-mRNA, plasma IGF-1 and nitrogen excretion in gastrectomized rats with liver cirrhosis

The growth hormone (GH)-insulin-like growth factor 1 (IGF-1) axis is impaired in liver cirrhosis. We determined the effects of GH and IGF-1 treatments in gastrectomized rats with thioacetamide-induced cirrhosis. GH did not increase hepatic IGF-1-mRNA, plasma IGF-1 or the tissue, i.e. gastrocnemius muscle IGF-1 level. IGF-1 administration increased plasma IGF-1 without increasing hepatic IGF-1-mRNA. GH and IGF-1 independently decreased postoperative urinary nitrogen excretion. We conclude that both GH and IGF-1 improve postoperative nitrogen metabolism. Furthermore, GH may exert its anabolic effects directly and/or via actions mediated by IGF-1 production, other than in the liver and in the skeletal muscle, in the setting of cirrhosis.