In vitro analysis of verapamil-induced immunosuppression: potent inhibition of T cell motility and lymphocytic transmigration through allogeneic endothelial cells.
BACKGROUND
Cyclosporine A (CsA) and tacrolimus prevent proliferation but not transendothelial migration of alloreactive lymphocytes into donor organs. As a result, serious adverse effects, such as nephrotoxicity and neurotoxicity, have been observed under CsA/tacrolimus therapy. The incorporation of new drugs with infiltration blocking properties might enhance the efficacy of the current immunosuppressive protocol, allowing lower CsA/tacrolimus dosage. Because Ca2+ plays a critical role in cell-cell interaction, the Ca2+-channel blocker verapamil might be a good cany. didate for supporting CsA/tacrolimus-based therapy.


METHODS
A T-cell endothelial cell coculture model or immobilized immunoglobulin G globulin chimeras were employed to investigate how S- and R- verapamil interfere with the lymphocytic infiltration process. The expression and arrangement of membranous adhesion receptors and cytoskeletal F-actin filaments were analyzed by fluorometric method in the presence of. verapamil.


RESULTS
Both verapamil enantiomers strongly inhibited lymphocyte infiltration. CD4+ and CD8+ T-cells were influenced to a similar extent with regard to horizontal locomotion (CD4+=CD8+), but to a different extent with regard to adhesion and penetration (CD4+ > CD8+). Moreover, penetration was blocked to a higher extent than was adhesion. ID50-values were 31 microM (CD4+-adhesion) and 11 microM (CD4+-penetration). Verapamil reduced P-selectin expression on endothelial cells and effectively down-regulated binding of T-cells to immobilized P-selectin immunoglobulin G globulins (ID50=4.4 microM; CD4+). A verapamil-induced reduction of intracellular F-actin in T-lymphocytes was proven to be mainly responsible for diminished cell locomotion.


CONCLUSIONS
The prevention of CD4+ T-cell penetration by verapamil might argue for its use as an adjunct to CsA/tacrolimus-based immunosuppressive therapy.
Blaheta
R A
RA
Department of General Surgery, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. Blaheta@em.uni-frankfurt.de
Hailer
N P
NP
Brude
N
N
Wittig
B
B
Leckel
K
K
Oppermann
E
E
Bachmann
M
M
Harder
S
S
Cinatl
J
J
Scholz
M
M
Bereiter-Hahn
J
J
Weber
S
S
Encke
A
A
Markus
B H
BH
D002465:Cell Movement / Q000187:drug effects; D015232:Dinoprostone / Q000494:pharmacology; D019040:E-Selectin / Q000096:biosynthesis / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects*; D018799:Intercellular Adhesion Molecule-1 / Q000187:drug effects; D016256:Lewis X Antigen / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D019007:P-Selectin / Q000096:biosynthesis / Q000187:drug effects; D011485:Protein Binding; D013601:T-Lymphocytes / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1 / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology* / Q000633:toxicity
D019040:E-Selectin; D016256:Lewis X Antigen; D016169:Lymphocyte Function-Associated Antigen-1; D019007:P-Selectin; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D014700:Verapamil; D015232:Dinoprostone