title: Role of hypertonic saline and pentoxifylline on neutrophil activation and tumor necrosis factor-alpha synthesis: a novel resuscitation strategy.
abstract: BACKGROUND
  Hypertonic saline (HS) and pentoxifylline (PTX) have been shown to modulate polymorphonuclear neutrophil (PMN) functions after shock and sepsis. We hypothesized that a combination of HS and PTX (HSPTX) would down-regulate PMN functions and inflammatory mediator synthesis more effectively than each alone, possibly by acting at different steps of the signaling pathways, ultimately leading to an enhanced effect.
  
  
  METHODS
  Whole blood from healthy volunteers was stimulated with lipopolysaccharide (LPS) (100 microg/mL), f-methionyl-leucyl-phenylalanine (1 micromol/L), and phorbol 12-myristate 13-acetate (1 microg/mL). Baseline oxidative burst was measured by flow cytometry. Two different concentrations of NaCl to achieve increases of 10 mmol/L (HS10) and 40 mmol/L (HS40) above isotonicity, simulating increases in sodium levels seen after infusion of 3% HS and 7.5% HS, were used. PTX (2 mmol/L), HS10, HS40, HSPTX10, and HSPTX40 were added to whole blood concomitantly to the activators. PMN CD14 and CD11b expression were measured by flow cytometry and tumor necrosis factor-alpha levels by enzyme-linked immunosorbent assay in LPS-stimulated whole blood.
  
  
  RESULTS
  The combination of PTX with HS10 and with HS40 markedly decreased LPS- (27 +/- 7 and 23 +/- 6 vs. 100; p < 0.01), f-methionyl-leucyl-phenylalanine- (54 +/- 11 and 55 +/- 8 vs. 100; p < 0.05), and phorbol 12-myristate 13-acetate- (30 +/- 4 and 54 +/- 9 vs. 100; p < 0.01 and p < 0.05, respectively) induced PMN oxidative burst. Furthermore, a significant decrease in LPS-induced neutrophil CD11b expression after PTX treatment (79 +/- 5 vs. 100; p < 0.05) and HSPTX40 (68 +/- 7 vs. 100; p < 0.05) was observed. HSPTX10 (7 +/- 0.6; p < 0.001) or HSPTX40 (6 +/- 1.4; p < 0.001) markedly decreased tumor necrosis factor-alpha production to levels similar to those observed with PTX alone (6.5 +/- 0.5; p < 0.001) and significantly lower than HS10 (110 +/- 4.9; p < 0.001) and HS40 alone (83 +/- 1.5; p < 0.001)
  
  
  CONCLUSIONS
  HSPTX down-regulates neutrophil activation and proinflammatory mediator synthesis more effectively that HS alone. HSPTX may have significant applications as a novel fluid resuscitation strategy in hemorrhagic shock.
authors.affiliation: Division of Trauma, Department of Surgery, University of California San Diego School of Medicine, CA 92103-8896, USA. rcoimbra@ucsd.edu
authors.forename: Raul
authors.initials: R
authors.lastname: Coimbra
authors.forename: William
authors.initials: W
authors.lastname: Loomis
authors.forename: Heidi
authors.initials: H
authors.lastname: Melbostad
authors.forename: Maria
authors.initials: M
authors.lastname: Tobar
authors.forename: Rafael D
authors.initials: RD
authors.lastname: Porcides
authors.forename: Rohan
authors.initials: R
authors.lastname: Lall
authors.forename: Troy
authors.initials: T
authors.lastname: Holbrook
authors.forename: David B
authors.initials: DB
authors.lastname: Hoyt
mesh_terms: D039481:CD11b Antigen / Q000378:metabolism; D004359:Drug Therapy, Combination; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects*; D010431:Pentoxifylline / Q000494:pharmacology*; D016897:Respiratory Burst; D012151:Resuscitation / Q000379:methods*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012771:Shock, Hemorrhagic / Q000097:blood / Q000517:prevention & control; D015398:Signal Transduction / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D039481:CD11b Antigen; D018950:Lipopolysaccharide Receptors; D012462:Saline Solution, Hypertonic; D014409:Tumor Necrosis Factor-alpha; D010431:Pentoxifylline