Volatile anesthetics induce caspase-dependent, mitochondria-mediated apoptosis in human T lymphocytes in vitro.
BACKGROUND
Volatile anesthetics modulate lymphocyte function during surgery, and this compromises postoperative immune competence. The current work was undertaken to examine whether volatile anesthetics induce apoptosis in human T lymphocytes and what apoptotic signaling pathway might be used.


METHODS
Effects of sevoflurane, isoflurane, and desflurane were studied in primary human CD3 T lymphocytes and Jurkat T cells in vitro. Apoptosis and mitochondrial membrane potential were assessed using flow cytometry after green fluorescent protein-annexin V and DiOC6-fluorochrome staining. Activity and proteolytic processing of caspase 3 was measured by cleaving of the fluorogenic effector caspase substrate Ac-DEVD-AMC and by anti-caspase-3 Western blotting. Release of mitochondrial cytochrome c was studied after cell fractionation using anti-cytochrome c Western blotting and enzyme-linked immunosorbent assays.


RESULTS
Sevoflurane and isoflurane induced apoptosis in human T lymphocytes in a dose-dependent manner. By contrast, desflurane did not exert any proapoptotic effects. The apoptotic signaling pathway used by sevoflurane involved disruption of the mitochondrial membrane potential and release of cytochrome c from mitochondria to the cytosol. In addition, the authors observed a proteolytic cleavage of the inactive p32 procaspase 3 to the active p17 fragment, increased caspase-3-like activity, and cleavage of the caspase-3 substrate poly-ADP-ribose-polymerase. Sevoflurane-induced apoptosis was blocked by the general caspase inhibitor Z-VAD.fmk. Death signaling was not mediated via the Fas/CD95 receptor pathway because neither anti-Fas/CD95 receptor antagonism nor FADD deficiency or caspase-8 deficiency were able to attenuate sevoflurane-mediated apoptosis.


CONCLUSIONS
Sevoflurane and isoflurane induce apoptosis in T lymphocytes via increased mitochondrial membrane permeability and caspase-3 activation, but independently of death receptor signaling.
Loop
Torsten
T
Division of Experimental Anesthesiology, Institute of Molecular Medicine, University Hospital, Hugstetterstrasse 55, D-79106 Freiburg, Germany. torsten@ana1.ukl.uni-freiburg.de
Dovi-Akue
David
D
Frick
Michael
M
Roesslein
Martin
M
Egger
Lotti
L
Humar
Matjaz
M
Hoetzel
Alexander
A
Schmidt
Rene
R
Borner
Christoph
C
Pahl
Heike L
HL
Geiger
Klaus K
KK
Pannen
Benedikt H J
BH
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D019169:Jurkat Cells; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000201:enzymology; D014835:Volatilization
D018685:Anesthetics, Inhalation; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases