TY - JOUR
T1 - Inducible nitric oxide synthase promotes cytokine expression in cardiac allografts but is not required for efficient rejection
AU - Mannon, Roslyn B.
AU - Roberts, Karen
AU - Ruiz, Philip
AU - Laubach, Victor
AU - Coffman, Thomas M.
N1 - Funding Information:
These studies were supported by NIH grant PO1-DK38103 and by grants from the Research Service of the Veterans Administration. Roslyn B. Mannon is supported by a NIH Mentored Clinical Scientist Development Award (1 K08 AI01389-01). The authors wish to thank Ms. Norma Turner for secretarial assistance and Mr. Robert Griffiths for expert technical assistance.
PY - 1999/9
Y1 - 1999/9
N2 - Background: Inducible nitric oxide synthase (iNOS) is enhanced during acute rejection. Pharmacologic inhibition of nitric oxide synthase (NOS) activity has had variable effects on graft survival in a number of animal models. To further characterize the requirement and effects of iNOS during acute allograft rejection, we examined rejection responses of mice completely deficient of iNOS. MethodsHeterotopic cardiac allografts were performed using wild-type and iNOS deficient mice (iNOS[-/-]) as recipients. Graft survival was determined by abdominal palpation. At days 3 and 7 following transplantation, grafts were harvested and analyzed histologically. Cytokine messenger RNA (mRNA) expression was measured by ribonuclease protection assay. ResultsMean survival time of cardiac allografts did not differ between wild-type (18 ± 3 days) and iNOS(-/-) recipients (16 ± 2 days). At 3 days, findings of moderate acute rejection were seen in both recipients groups, although modestly reduced in iNOS(-/-) mice. By 7 days, allografts in both groups demonstrated severe rejection. Within grafts at day 3, there was a 3-fold reduction in IL-1β expression and a 4-fold reduction in IL-1RA in iNOS(-/-) recipients (p = 0.03 and p = 0.04, respectively) compared to wild-type recipients. Expression of other proinflammatory cytokines was detected in the grafts from both recipients, but was not significantly different. Finally, rejection responses to iNOS(-/-) cardiac allografts were nearly identical to wild-type allografts.ConclusionsRejection of cardiac allografts by iNOS(-/-) mice occurs in a similar fashion to wild-type recipients, with extensive inflammation and proinflammatory cytokine production. While iNOS may play a role in cytokine induction by macrophages, these studies suggest that iNOS is not required for efficient cardiac graft rejection. Copyright (C) 1999 International Society for Heart and Lung Transplantation.
AB - Background: Inducible nitric oxide synthase (iNOS) is enhanced during acute rejection. Pharmacologic inhibition of nitric oxide synthase (NOS) activity has had variable effects on graft survival in a number of animal models. To further characterize the requirement and effects of iNOS during acute allograft rejection, we examined rejection responses of mice completely deficient of iNOS. MethodsHeterotopic cardiac allografts were performed using wild-type and iNOS deficient mice (iNOS[-/-]) as recipients. Graft survival was determined by abdominal palpation. At days 3 and 7 following transplantation, grafts were harvested and analyzed histologically. Cytokine messenger RNA (mRNA) expression was measured by ribonuclease protection assay. ResultsMean survival time of cardiac allografts did not differ between wild-type (18 ± 3 days) and iNOS(-/-) recipients (16 ± 2 days). At 3 days, findings of moderate acute rejection were seen in both recipients groups, although modestly reduced in iNOS(-/-) mice. By 7 days, allografts in both groups demonstrated severe rejection. Within grafts at day 3, there was a 3-fold reduction in IL-1β expression and a 4-fold reduction in IL-1RA in iNOS(-/-) recipients (p = 0.03 and p = 0.04, respectively) compared to wild-type recipients. Expression of other proinflammatory cytokines was detected in the grafts from both recipients, but was not significantly different. Finally, rejection responses to iNOS(-/-) cardiac allografts were nearly identical to wild-type allografts.ConclusionsRejection of cardiac allografts by iNOS(-/-) mice occurs in a similar fashion to wild-type recipients, with extensive inflammation and proinflammatory cytokine production. While iNOS may play a role in cytokine induction by macrophages, these studies suggest that iNOS is not required for efficient cardiac graft rejection. Copyright (C) 1999 International Society for Heart and Lung Transplantation.
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U2 - 10.1016/S1053-2498(99)00052-2
DO - 10.1016/S1053-2498(99)00052-2
M3 - Article
C2 - 10528743
AN - SCOPUS:0032862615
SN - 1053-2498
VL - 18
SP - 819
EP - 827
JO - Journal of Heart and Lung Transplantation
JF - Journal of Heart and Lung Transplantation
IS - 9
ER -