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Determination of Interleukin-6 in Lung Transplantation: Association With Primary Graft Dysfunction
Determination of Interleukin-6 in Lung Transplantation: Association With Primary Graft Dysfunction I. Moreno, R. Vicente, F. Ramos, J.L. Vicente, and M. Barberá ABSTRACT Introduction and Objective. Primary graft dysfunction (PGD) secondary to damage caused by ischemia/reperfusion is responsible for significant morbidity. It constitutes the main cause of early death following implantation. Our objective was to verify the association between PGD and activation of the inflammatory cascade by measuring interleukin-6 (IL-6) in the blood and the bronchoalveolar lavage (BAL) of the recipient. Materials and Methods. The 31 patients, including 22 bipulmonary and 9 unipulmonary cases, had severe PGD (ISHLT grade II) defined by: (1) radiographic infiltrates during the first 72 hours after transplantation, (2) PO2/FiO2 ratio ⬍200 in the first 72 hours after the operation, and (3) no other cause of dysfunction. BAL and peripheral arterial blood samples were extracted prior to implantation (baseline level) and at 12, 24, and 48 hours after reperfusion. Samples were frozen to ⫺80°C until determination of IL-6 using an immunoassay technique (ELISA). Results. In the 31 transplants (100%), there were elevated IL-6 contents in the BAL and blood compared with the baseline level (P ⬍ .0001). Among 11 patients with severe PGD (38.70%) In the BAL samples the concentration of IL-6 was significantly elevated (P ⬍ .05) compared with patients without PGD (P ⬍ .031). These finding were also observed in blood (P ⬍ .016) obtained at 12 hours. The analyses at 24 and 48 hours showed higher levels of IL-6 in the PGD group, although they were not significant. Conclusions. There was a significant elevation of IL-6 in blood and BAL during the first few hours after reperfusion of the graft, which was directly related to the development of PGD.
L
UNG transplantation is accepted as a therapeutic option in a select number of patients with terminal lung disease refractory to other forms of clinical treatment.1 In view of the large variety of synonyms used to refer to the same syndrome, the International Society for Heart and Lung Transplantation (ISHLT) Working Group2 reviewed the literature to precisely define primary graft dysfunction (PGD). PGD secondary to damage caused by ischemia/ reperfusion is responsible for significant morbidity, constituting the main cause of early death following implantation. Its incidence varyies between 11% and 57% depending on the study.3 After reperfusion of the graft, activation of inflammation factors takes place with infiltration by neutrophils and the release of cytokines that may contribute to PGD development. An attempt has been made to reduce this reaction by the administration of inhaled nitric oxide (iNO) because of its immunomodulatory effects.4
Our objective was to verify the association between PGD and activation of the inflammatory cascade by measuring interleukin-6 (IL-6) in the blood and the bronchoalveolar lavage (BAL) of the recipient. MATERIALS AND METHODS After approval of the study by the Ethical Committee of our hospital and obtaining informed consent, a prospective study was made of all lung transplantations performed from June 2005 to December 2006. Severe PGD (ISHLT grade II) was defined as follows: (1) radiographic infiltrates during the first 72 hours after From the Departament of Anesthesiology and Critical Care, “La Fe” University Hospital, Valencia, Spain. Address reprint requests to Ignacio Moreno Puigdollers, Calle Matias Perelló 27, pta 6. 46005 Valencia, Spain. E-mail: [email protected]
© 2007 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/07/$–see front matter doi:10.1016/j.transproceed.2007.07.056
Transplantation Proceedings, 39, 2425–2426 (2007)
2425
2426
MORENO, VICENTE, RAMOS ET AL
transplantation, (2) PO2/FiO2 ratio ⬍200 in the first 72 hours after the operation, and (3) no other cause of dysfunction-acute rejection, venous anastomosis obstruction, cardiogenic pulmonary edema, or pneumonia. For anesthetic induction, all recipients were administered iNO (INOmax from INO Therapeutic, Clinton, NJ) at a concentration of 10 ppm during the first 48 hours, or previous to withdrawal of mechanical ventilation, if this was instigated prior to the second day of the postoperative period. BAL and peripheral arterial blood Samples were obtained prior to implantation (baseline level) as well as at 12, 24, and 48 hours after reperfusion. After filtration, centrifugation, and collection of the supernate, samples were frozen to ⫺80°C until determination of IL-6 using an immunoassay technique (ELISA). The statistical analysis of the BAL and blood samples used the Wilcoxon nonparametric test for paired samples and the computer program SPSS version 12.0S for Windows (SPSS Inc., Chicago, Ill).
RESULTS
The 31 patients (16 men and 15 women) included 22 bipulmonary and 9 unipulmonary transplantations with an age range of 14 to 65 years. The samples were extracted according to the planned schedule except in 19 cases where the BAL at 48 hours was not available because the patient had already been extubated. In the 31 transplants studied (100%), there was elevation of IL-6 in the BAL and blood compared with the baseline level (P ⬍ .0001). A total of 11 patients presented criteria of severe PGD (38.70%). As shown in Table 1, the elevated concentration of IL-6 was significant (P ⬍ .05) compared with patients without PGD in the samples of BAL (P ⬍ .031) and blood (P ⬍ .016) Table 1. IL-6 Concentration: a Comparison at 12, 24, and 48 Hours
BAL 12 h No PGD BAL 12 h PGD Blood 12 h No PGD Blood 12 h PGD BAL 24 h No PGD BAL 24 h PGD Blood 24 h No PGD Blood 24 h PGD BAL 48 h No PGD BAL 48 h PGD Blood 48 h No PGD Blood 48 h PGD
Mean (pg/mL)
⫹/⫺ SD
P⬍
406.13 482.07 177.13 310.50 393.50 494.27 109.50 153.50 415.40 462.27 35.00 50.67
89.35 59.64 111.86 140.36 74.36 55.84 71.70 114.90 159.01 75.53 18.65 51.35
.031* .016* .116 .424 .721 .814
Abbreviations: BAL, bronchoalveolar lavage; PGD, primary graft dysfunction. *P ⬍ .05.
obtained at 12 hours. The analyses at 24 and 48 hours showed higher levels of IL-6 in the PGD group, although they were not significant. DISCUSSION
PGD has always been a motive for study and analysis because of its clinical and economic repercussions. King et al5 concluded that patients who presented with this lesion spent twice as much time in the Critical Care Unit and in hospital, considerably increasing the economic cost as well as the postoperative mortality. Apart from the possible factors related to the donor, recipient, and procedure,6 Mal et al7 analyzed the development of an inflammatory process where the activation of leukocytes and release of interleukins plays an important role. Studies by Pham et al8 reported elevated levels of IL-6 in relation to graft dysfunction. More specifically, Mathur et al9 noted elevated IL-6, IL-8, and IL-10 concentrations in the blood of patients with PGD just a few hours after reperfusion of the graft. Our analysis introduced the determination of IL-6 in BAL to quantify local inflammatory activation in addition to the systemic activation that is reflected in the blood samples. In summary, this study concludes that there is a significant elevation of IL-6 in blood and BAL during the first few hours after reperfusion of the graft and that it is directly related to the development of PGD. REFERENCES 1. Thabut, et al: Primary graft failure following lung transplantation. Predictive factors of mortality. Chest 121:1876, 2002 2. Christie JD, et al: Report of the ISHLT working group on primary lung graft dysfunction. J Heart Lung Transplant 24:1451, 2005 3. Arcasoy SM, et al: Lung transplantation. N Engl J Med 340:1081, 1999 4. Barbra M, et al: Attenuation of lung graft reperfusion injury by a nitric oxide donor. J Thorac Cardiovasc Surg 113:327, 1997 5. King R, et al: Reperfusion injury significantly impacts clinical outcome after pulmonary transplantation Ann Thorac Surg 69: 1681, 2000 6. Christie JD, et al: Clinical risk factors for primary graft failure following lung transplantation. Chest 124:1232, 2003 7. Mal H, et al: Early release of proinflamatory cytokines after lung transplantation. Chest 113:645, 1998 8. Pham, et al: Interleukin-6 release during early reperfusion predicts graft function in human lung transplantation. J Heart Lung Transplant11:1017, 1992 9. Mathur A, et al: Cytokine profile after lung transplantation: correlation with allograft injury. Ann Thorac Surg 81:1844, 2006
L
UNG transplantation is accepted as a therapeutic option in a select number of patients with terminal lung disease refractory to other forms of clinical treatment.1 In view of the large variety of synonyms used to refer to the same syndrome, the International Society for Heart and Lung Transplantation (ISHLT) Working Group2 reviewed the literature to precisely define primary graft dysfunction (PGD). PGD secondary to damage caused by ischemia/ reperfusion is responsible for significant morbidity, constituting the main cause of early death following implantation. Its incidence varyies between 11% and 57% depending on the study.3 After reperfusion of the graft, activation of inflammation factors takes place with infiltration by neutrophils and the release of cytokines that may contribute to PGD development. An attempt has been made to reduce this reaction by the administration of inhaled nitric oxide (iNO) because of its immunomodulatory effects.4
Our objective was to verify the association between PGD and activation of the inflammatory cascade by measuring interleukin-6 (IL-6) in the blood and the bronchoalveolar lavage (BAL) of the recipient. MATERIALS AND METHODS After approval of the study by the Ethical Committee of our hospital and obtaining informed consent, a prospective study was made of all lung transplantations performed from June 2005 to December 2006. Severe PGD (ISHLT grade II) was defined as follows: (1) radiographic infiltrates during the first 72 hours after From the Departament of Anesthesiology and Critical Care, “La Fe” University Hospital, Valencia, Spain. Address reprint requests to Ignacio Moreno Puigdollers, Calle Matias Perelló 27, pta 6. 46005 Valencia, Spain. E-mail: [email protected]
© 2007 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/07/$–see front matter doi:10.1016/j.transproceed.2007.07.056
Transplantation Proceedings, 39, 2425–2426 (2007)
2425
2426
MORENO, VICENTE, RAMOS ET AL
transplantation, (2) PO2/FiO2 ratio ⬍200 in the first 72 hours after the operation, and (3) no other cause of dysfunction-acute rejection, venous anastomosis obstruction, cardiogenic pulmonary edema, or pneumonia. For anesthetic induction, all recipients were administered iNO (INOmax from INO Therapeutic, Clinton, NJ) at a concentration of 10 ppm during the first 48 hours, or previous to withdrawal of mechanical ventilation, if this was instigated prior to the second day of the postoperative period. BAL and peripheral arterial blood Samples were obtained prior to implantation (baseline level) as well as at 12, 24, and 48 hours after reperfusion. After filtration, centrifugation, and collection of the supernate, samples were frozen to ⫺80°C until determination of IL-6 using an immunoassay technique (ELISA). The statistical analysis of the BAL and blood samples used the Wilcoxon nonparametric test for paired samples and the computer program SPSS version 12.0S for Windows (SPSS Inc., Chicago, Ill).
RESULTS
The 31 patients (16 men and 15 women) included 22 bipulmonary and 9 unipulmonary transplantations with an age range of 14 to 65 years. The samples were extracted according to the planned schedule except in 19 cases where the BAL at 48 hours was not available because the patient had already been extubated. In the 31 transplants studied (100%), there was elevation of IL-6 in the BAL and blood compared with the baseline level (P ⬍ .0001). A total of 11 patients presented criteria of severe PGD (38.70%). As shown in Table 1, the elevated concentration of IL-6 was significant (P ⬍ .05) compared with patients without PGD in the samples of BAL (P ⬍ .031) and blood (P ⬍ .016) Table 1. IL-6 Concentration: a Comparison at 12, 24, and 48 Hours
BAL 12 h No PGD BAL 12 h PGD Blood 12 h No PGD Blood 12 h PGD BAL 24 h No PGD BAL 24 h PGD Blood 24 h No PGD Blood 24 h PGD BAL 48 h No PGD BAL 48 h PGD Blood 48 h No PGD Blood 48 h PGD
Mean (pg/mL)
⫹/⫺ SD
P⬍
406.13 482.07 177.13 310.50 393.50 494.27 109.50 153.50 415.40 462.27 35.00 50.67
89.35 59.64 111.86 140.36 74.36 55.84 71.70 114.90 159.01 75.53 18.65 51.35
.031* .016* .116 .424 .721 .814
Abbreviations: BAL, bronchoalveolar lavage; PGD, primary graft dysfunction. *P ⬍ .05.
obtained at 12 hours. The analyses at 24 and 48 hours showed higher levels of IL-6 in the PGD group, although they were not significant. DISCUSSION
PGD has always been a motive for study and analysis because of its clinical and economic repercussions. King et al5 concluded that patients who presented with this lesion spent twice as much time in the Critical Care Unit and in hospital, considerably increasing the economic cost as well as the postoperative mortality. Apart from the possible factors related to the donor, recipient, and procedure,6 Mal et al7 analyzed the development of an inflammatory process where the activation of leukocytes and release of interleukins plays an important role. Studies by Pham et al8 reported elevated levels of IL-6 in relation to graft dysfunction. More specifically, Mathur et al9 noted elevated IL-6, IL-8, and IL-10 concentrations in the blood of patients with PGD just a few hours after reperfusion of the graft. Our analysis introduced the determination of IL-6 in BAL to quantify local inflammatory activation in addition to the systemic activation that is reflected in the blood samples. In summary, this study concludes that there is a significant elevation of IL-6 in blood and BAL during the first few hours after reperfusion of the graft and that it is directly related to the development of PGD. REFERENCES 1. Thabut, et al: Primary graft failure following lung transplantation. Predictive factors of mortality. Chest 121:1876, 2002 2. Christie JD, et al: Report of the ISHLT working group on primary lung graft dysfunction. J Heart Lung Transplant 24:1451, 2005 3. Arcasoy SM, et al: Lung transplantation. N Engl J Med 340:1081, 1999 4. Barbra M, et al: Attenuation of lung graft reperfusion injury by a nitric oxide donor. J Thorac Cardiovasc Surg 113:327, 1997 5. King R, et al: Reperfusion injury significantly impacts clinical outcome after pulmonary transplantation Ann Thorac Surg 69: 1681, 2000 6. Christie JD, et al: Clinical risk factors for primary graft failure following lung transplantation. Chest 124:1232, 2003 7. Mal H, et al: Early release of proinflamatory cytokines after lung transplantation. Chest 113:645, 1998 8. Pham, et al: Interleukin-6 release during early reperfusion predicts graft function in human lung transplantation. J Heart Lung Transplant11:1017, 1992 9. Mathur A, et al: Cytokine profile after lung transplantation: correlation with allograft injury. Ann Thorac Surg 81:1844, 2006