Ketamine affects in vitro differentiation of monocyte into immature dendritic cells
Krzysztof Laudanski1, Meng Qing, Hanna Oszkiel
1From the Department of Anesthesiology, University of Pennsylvania, Philadelphia, Pennsylvania (K.L., M.Q.); Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland (H.O.); Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland (M.Z.); Faculty of Medicine, Ivano-Frankivsk Medical Institute, Ivano-Frankivsk, Ukraine (N.L.); Department of Nephrology with Dialysis Unit, Central Military Hospital, Warsaw, Poland (Z.N.); and Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania (G.S.W.).
Background:
Monocytes (MOs) have the unique ability to differentiate into immature dendritic cells (iDCs) (MO→iDC) under the influence of interleukin-4 and granulocyte-monocyte colony-stimulating factor (IL-4&GM-CSF). In this study, the authors investigated the influence of ketamine on the process of MO→iDC.
Methods:
iDCs were cultured from MO obtained from 36 subjects in the presence of IL-4 and GM-CSF and ketamine at 100, 10, and 1 μg/ml for 5 days. In some of the experiments, the authors used nonspecific N-methyl-D-aspartate (NMDA) receptor antagonist MK-801, NMDA, or a neutralizing antibody for transforming growth factor β (TGFβ). The expression of surface markers and functional assays were used to assess the effect of ketamine on IL-4&GM-CSF-stimulated MO. IL-4&GM-CSF-stimulated MO's supernatants were assessed for cytokine levels.
Results:
Ketamine at 10 μg/ml, and higher concentrations, diminished the expression of CD1a on IL-4&GM-CSF-stimulated MO and retarded both their ability to process DQ ovalbumin and mixed lymphocyte reaction stimulation. The addition of ketamine to IL-4&GM-CSF-differentiated MO resulted in the persistent expression of CD14 and unchanged expression of CD86 and CD206. The phagocytic abilities of IL-4&GM-CSF-differentiated MO were not changed by ketamine. MK-801, a nonselective NMDA agonist, mimicked ketamine's effect on MO→iDC differentiation. Adding exogenous NMDA to IL-4&GM-CSF-stimulated MO in the presence of ketamine partially restored the level of CD1a. TGFβ was elevated in supernatants of IL-4&GM-CSF-stimulated MO in the presence of ketamine. Adding neutralizing TGFβ antibody or TGFβR1 blocker (SB431542) resulted in the full recovery of MO→iDC, despite the presence of ketamine.
Conclusions:
Ketamine diminishes the process of MO→iDC in vitro. This is mediated via NMDA-dependent mechanisms and TGFβ.
