Takeaki Matsuda

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.

Glutamine as an immunoenhancing nutrient.

New strategies for immunonutritional support include administration of special nutrients such as glutamine. Glutamine is important in several key metabolic processes of immune cells and enterocytes. Exogenous glutamine augments the functions of lymphocytes and macrophages. Neutrophils also reportedly utilize glutamine at a significant rate. Our recent studies demonstrated that glutamine enhances neutrophil function. This article focuses on the effects of glutamine on neutrophil function in surgical stress. Enteral glutamine administration enhanced peritoneal and hepatic bacterial clearance in our rat peritonitis model. Furthermore, IV glutamine supplementation improved the outcome of animals with severe surgical stress. Our in vitro study revealed that supplemental glutamine augmented the bacterial killing function of neutrophils from postoperative patients. Glutamine increased phagocytosis of the neutrophils. In addition, glutamine dose-dependently increased production of reactive oxygen intermediates (ROI) by neutrophils. Thus, our studies suggest that glutamine supplementation may improve bactericidal function of neutrophils by increasing both phagocytosis and ROI production. In conclusion, glutamine plays an important role in neutrophil function. Glutamine may be useful for the prevention, and treatment, of severe infection in critical illness and trauma.

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.

Glutamine-Enriched Enteral Diet Enhances Bacterial Clearance in Protracted 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.

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/insulin-like growth factor 1 axis alterations contribute to disturbed protein metabolism in cirrhosis patients after hepatectomy

BACKGROUND/AIM Liver cirrhosis is accompanied by a fall in whole-body protein turnover and alterations of the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis. However, the influence of liver cirrhosis on the GH/IGF-1 axis in the perioperative period, and the contribution of the GH/IGF-1 axis alteration in cirrhosis to postoperative nitrogen metabolism are not known. METHODS Plasma GH, IGF-1 and IGF binding protein 3 (IGF-BP3) levels were measured sequentially in patients undergoing hepatectomy with or without cirrhosis. Postoperative nitrogen excretion and whole-body protein turnover rate were also determined. RESULTS Preoperative plasma IGF-1 level showed a negative correlation with indocyanine green retention rate. Cirrhosis patients undergoing hepatectomy had low IGF-1 and IGF-BP3 levels, despite extremely high GH levels in the perioperative period. Perioperative IGF-1 levels were lower in patients with postoperative complications than in those without complications. Postoperative nitrogen excretion was higher and whole-body protein turnover rate was lower in patients with cirrhosis than in those without cirrhosis. The post-operative IGF-1 level showed a positive correlation with whole-body protein turnover rate. CONCLUSIONS Postoperative hepatic IGF-1 production may be severely disturbed in patients with cirrhosis, and the impaired IGF-1 production contributes to the suppressed postoperative protein metabolism in cirrhosis. It may be appropriate to increase plasma IGF-1 level in patients with cirrhosis to enhance postoperative protein metabolism and improve the postoperative outcome.

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

ABSTRACT 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-CD11 b 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.

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.

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

ABSTRACT 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 × 106/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°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°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.

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.