Synergistic inhibitory effect of cyclosporin A and vitamin D derivatives on T-lymphocyte proliferation in active ulcerative colitis.
OBJECTIVE
1,25-Dihydroxyvitamin D3 [1,25(OH)2D3], the hormonal active form of vitamin D3, could represent a potentially therapeutic agent in autoimmune diseases. Cyclosporin A (CsA) shows immunoregulatory properties, which, in many respects, seem to be similar to those of 1,25(OH)2D3. Our aim was to investigate the possible synergistic effect exerted by CsA in combination with 1,25(OH)2D3 or its nonhypercalcemic analogues, EB 1089 and KH 1060, on the proliferative response of T lymphocytes obtained from active ulcerative colitis patients.


METHODS
The T lymphocyte-enriched population was treated with phytohemagglutinin and CsA (doses from 1 ng to 1000 ng/ml) alone or in association with 1,25(OH)2D3 or EB 1089 or KH 1060 (0.1, 1, 10 nM final concentration). Cell proliferation was determined by [3H]thymidine incorporation and analyzed on day 5 of culture.


RESULTS
After incubation with CsA, T lymphocyte proliferation was significantly inhibited in comparison with the vehicle-treated cultures. However, T lymphocytes from ulcerative colitis patients were significantly more sensitive to CsA than those from healthy controls. The inhibition in T lymphocyte proliferation, after treatment of the cultures with CsA associated with either 1,25(OH)2D3 or EB 1089 or KH 1060, was synergistic at well-defined concentrations.


CONCLUSIONS
Taking into account the lowest CsA dose (1 ng/ml), the highest synergistic inhibition in the proliferation of T lymphocytes prepared from ulcerative colitis patients was found combining CsA and 10 nM of 1,25(OH)2D3 or 10 nM of EB 1089 or KH 1060 at the three concentrations. The results obtained, associating the lowest CsA dose and the lowest KH 1060 concentration, may suggest an alternative therapeutic approach in these patients, reducing the dose, and consequently the toxicity, of CsA.
Stio
Maria
M
Department of Biochemical Sciences, University of Florence, Italy.
Treves
Cristina
C
Celli
Alessandra
A
Tarantino
Ottaviano
O
d'Albasio
Giuseppe
G
Bonanomi
Andrea Giovanni
AG
D000328:Adult; D002117:Calcitriol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use; D002468:Cell Physiological Phenomena / Q000187:drug effects*; D003093:Colitis, Ulcerative / Q000188:drug therapy / Q000503:physiopathology*; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000187:drug effects*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use
D007166:Immunosuppressive Agents; C074279:KH 1060; D014807:Vitamin D; D016572:Cyclosporine; D002117:Calcitriol; C078903:seocalcitol