Ketamine inhibits tumor necrosis factor secretion by RAW264.7 murine macrophages stimulated with antibiotic-exposed strains of community-associated, methicillin-resistant Staphylococcus aureus.
BACKGROUND
Infections caused by community-associated strains of methicillin-resistant Staphylococcus aureus (CA-MRSA) are associated with a marked and prolonged host inflammatory response. In a sepsis simulation model, we tested whether the anesthetic ketamine inhibits the macrophage TNF response to antibiotic-exposed CA-MRSA bacteria via its antagonism of N-methyl-D-aspartate (NMDA) receptors. RAW264.7 cells were stimulated for 18 hrs with 105 to 107 CFU/mL inocula of either of two prototypical CA-MRSA isolates, USA300 strain LAC and USA400 strain MW2, in the presence of either vancomycin or daptomycin. One hour before bacterial stimulation, ketamine was added with or without MK-801 (dizocilpine, a chemically unrelated non-competitive NMDA receptor antagonist), APV (D-2-amino-5-phosphono-valerate, a competitive NMDA receptor antagonist), NMDA, or combinations of these agents. Supernatants were collected and assayed for TNF concentration by ELISA.


RESULTS
RAW264.7 cells exposed to either LAC or MW2 in the presence of daptomycin secreted less TNF than in the presence of vancomycin. The addition of ketamine inhibited macrophage TNF secretion after stimulation with either of the CA-MRSA isolates (LAC, MW2) in the presence of either antibiotic. The NMDA inhibitors, MK-801 and APV, also suppressed macrophage TNF secretion after stimulation with either of the antibiotic-exposed CA-MRSA isolates, and the effect was not additive or synergistic with ketamine. The addition of NMDA substrate augmented TNF secretion in response to the CA-MRSA bacteria, and the addition of APV suppressed the effect of NMDA in a dose-dependent fashion.


CONCLUSIONS
Ketamine inhibits TNF secretion by MRSA-stimulated RAW264.7 macrophages and the mechanism likely involves NMDA receptor antagonism. These findings may have therapeutic significance in MRSA sepsis.
Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA. tom.spentzas@gmail.com
Thomas
T
Spentzas
Rebekah K H
RK
Shapley
Carlos Acuna
CA
Aguirre
Elizabeth
E
Meals
Lauren
L
Lazar
Mark S
MS
Rayburn
Brett S
BS
Walker
B Keith
BK
English
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002460:Cell Line; D017576:Daptomycin / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004357:Drug Synergism; D007649:Ketamine / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification / Q000502:physiology*; D051379:Mice; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D014640:Vancomycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D016194:Receptors, N-Methyl-D-Aspartate; D014409:Tumor Necrosis Factor-alpha; D016202:N-Methylaspartate; D007649:Ketamine; D016291:Dizocilpine Maleate; D014640:Vancomycin; D015763:2-Amino-5-phosphonovalerate; D017576:Daptomycin
Pediatr Crit Care Med. 2005 May;6(3 Suppl):S3-5
15857554
J Infect Dis. 2008 Oct 15;198(8):1166-70
18729780
N Engl J Med. 2006 Aug 17;355(7):666-74
16914702
MMWR Morb Mortal Wkly Rep. 1999 Aug 20;48(32):707-10
21033181
Curr Med Chem. 2009;16(24):3152-67
19689289
Biochem Biophys Res Commun. 2004 May 28;318(2):496-502
15120628
JAMA. 1991 Sep 4;266(9):1242-5
1870250
J Infect Dis. 2010 Jan 15;201(2):241-54
20001858
JAMA. 2007 Oct 17;298(15):1763-71
17940231
Infect Immun. 2007 Feb;75(2):830-7
17118979
Annu Rev Biochem. 1988;57:505-18
3052281
J Infect Dis. 1999 Jul;180(1):116-21
10353869
Proc Natl Acad Sci U S A. 1975 Sep;72(9):3666-70
1103152
Clin Microbiol Rev. 2009 Apr;22(2):240-73, Table of Contents
19366914
Crit Care Med. 2002 Jun;30(6):1365-78
12072696
Crit Care Clin. 1997 Jul;13(3):553-74
9246530
Toxicol Appl Pharmacol. 2005 Apr 1;204(1):27-35
15781291
J Neurosci. 1989 Sep;9(9):3040-57
2552039
J Neurosci. 1987 Oct;7(10):3343-9
3312511
Circ Shock. 1994 Nov;44(3):160-8
7600640
Adv Exp Med Biol. 2009;647:1-7
19760063
J Biol Chem. 1999 Nov 19;274(47):33419-25
10559223
Pediatr Infect Dis J. 2004 Jul;23(7):619-24
15247599
Curr Opin Infect Dis. 2008 Apr;21(2):147-52
18317037
Anaesthesist. 1975 Jun;24(6):260-3
1155748
Ther Drug Monit. 1995 Feb;17(1):95-100
7725385
J Chromatogr B Analyt Technol Biomed Life Sci. 2008 Dec 1;876(1):137-42
18976970
Pediatr Infect Dis J. 2009 Jul;28(7):572-6
19478685
Blood. 1999 May 1;93(9):2876-83
10216082
Clin Infect Dis. 2009 Mar 1;48(5):612-4
19191649
Crit Care Med. 2005 Dec;33(12 Suppl):S506-9
16340435
Br J Anaesth. 1979 Dec;51(12):1167-73
526385
J Neurophysiol. 2002 Dec;88(6):3167-74
12466438
J Neurotrauma. 1997 Sep;14(9):651-63
9337127
Antimicrob Agents Chemother. 2007 Dec;51(12):4255-60
17923487
Chem Biol. 2004 Jul;11(7):887-8
15271343
Clin Microbiol Rev. 2002 Jan;15(1):95-110
11781269
Science. 1989 Jun 16;244(4910):1360-2
2660263
Lancet. 1998 Mar 28;351(9107):950-3
9734942
Lancet. 2002 Mar 2;359(9308):753-9
11888586
Infect Immun. 1989 Jan;57(1):291-4
2642470
Lancet Infect Dis. 2009 Jun;9(6):384-92
19467478
Can J Anaesth. 2001 Sep;48(8):819-23
11546726
Neurochem Int. 2006 May-Jun;48(6-7):541-6
16517016
J Infect Dis. 2006 Dec 15;194(12):1761-70
17109350
Antimicrob Agents Chemother. 2006 Jun;50(6):2225-7
16723590
FEBS Lett. 1987 Oct 19;223(1):143-7
2889618
Pediatr Crit Care Med. 2009 May;10(3):323-7
19307811
Anesth Analg. 1999 Sep;89(3):665-9
10475301