Apoptogenic effect of fentanyl on freshly isolated peripheral blood lymphocytes.
BACKGROUND
Opioids may trigger the apoptotic death of widely ranging cell types, and apoptosis contributes to the immune deficiency of critically ill patients and subjects experiencing surgical trauma. There is evidence that an altered mitochondrial membrane potential constitutes an early and irreversible step in the death-signaling pathway of apoptosis. This study investigated whether fentanyl, a opioid widely used in the management of these patients, may induce apoptosis of T cells by altering their mitochondrial membrane potential.


METHODS
Peripheral blood lymphocytes were cultured in the presence of 30 ng fentanyl for 60 (time 1), 90 (time 2), and 120 (time 3) minutes, respectively. The cells then were processed for assessment of mitochondrial membrane potential by means of flow cytometry and confocal scanning microscopy. Furthermore, production of reactive oxygen species, expression of the Fas-Fas L pro-apoptotic pathway, and apoptosis frequency were measured by means of flow cytometry. Control cells were incubated for the same times in the complete culture medium without the drug.


RESULTS
Flow cytometry analysis showed a significantly increased rate (p < 0.05) of lymphocytes with disrupted mitochondrial membrane potential after incubation with fentanyl for 90 and 120 minutes, as compared with both control cells and lymphocytes cultured in the presence of fentanyl for 60 minutes. In addition, as early as 60 minutes after exposure to fentanyl, cells displayed a disrupted mitochondrial membrane potential when this was assayed by means of confocal laser scanning. These findings were associated with increased production of reactive oxygen species. The frequency of apoptotic lymphocytes was markedly increased (p < 0.05) after 120 minutes of incubation, as compared with untreated cells and cells exposed to fentanyl for only 60 and 90 minutes. Expression of Fas-FasL was not substantially affected by exposure to fentanyl.


CONCLUSIONS
Fentanyl may induce a time-dependent apoptosis of lymphocytes by altering their mitochondrial redox metabolism.
Department of Anestesia and Intensive Care, La Sapienza University, Rome, Italy. giovanna.delogu@uniroma1.it
Giovanna
G
Delogu
Sonia
S
Moretti
Adriana
A
Antonucci
Maurizio
M
Marandola
Guglielmo
G
Tellan
Patrizio
P
Sale
Roberto
R
Carnevali
Giuseppe
G
Famularo
D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D003422:Critical Care / Q000379:methods; D053222:Fas Ligand Protein; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
D000701:Analgesics, Opioid; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D005283:Fentanyl