RESUMO
BACKGROUND: Since the first reported series in 1995, transplantation of lungs recovered through donation after circulatory determination of death (DCDD) has steadily increased. In some European and Australian centers, controlled DCDD accounts for 15% to 30% of all transplanted lungs. Several transplant centers have reported early and midterm outcomes similar to those associated with the use of donors after brain death. Despite these encouraging reports, less than 2% of all lung transplants in the United States are performed using donors after circulatory determination of death. METHODS: An electronic search from January 1990 to January 2014 was performed to identify series reporting lung transplant outcomes using controlled DCDD. Data from these publications were analyzed in terms of donor characteristics, donation after circulatory determination of death protocols, recipients' characteristics, and early and midterm outcomes. RESULTS: Two hundred twenty-two DCDDs were transplanted into 225 recipients. The rate of primary graft dysfunction grade 3 ranged from 3% to 36%. The need for extracorporeal membrane oxygenation support after transplantation ranged from 0% to 18%. The average intensive care unit stay ranged from 4 to 8.5 days and the average hospital stay ranged from 14 to 35 days. Thirty-day mortality ranged from 0% to 11% and 1-year survival from 88% to 100%. CONCLUSION: Under clinical protocols developed and strictly applied by several experienced lung transplant programs, lungs from controlled DCDD have produced outcomes very similar to those observed with brain death donors.
Assuntos
Morte Encefálica/diagnóstico , Transplante de Pulmão/métodos , Doadores de Tecidos/provisão & distribuição , Obtenção de Tecidos e Órgãos/organização & administração , Humanos , Disfunção Primária do Enxerto/prevenção & controleRESUMO
A 49-year-old woman underwent bilateral lung transplantation for advanced idiopathic pulmonary fibrosis. During the postoperative period she received immunosuppressive medications as well as corticosteroids. Aspergillus fumigatus grew from a sputum sample, and she was treated with nebulized amphotericin. She was discharged on tacrolimus and prednisone. After initially doing well, she required re-hospitalization for treatment of cytomegalovirus and Pseudomonas aeruginosa pneumonia. She was treated with ganciclovir and cefepime and, after a 2-week hospitalization, was discharged. Seven months after transplantation she developed progressive sinusitis, treated with antibiotics and sinus debridement surgery. Aspergillus organisms were recovered and, at the periphery of the tangled masses of Aspergillus hyphae, numerous amebic cysts were also identified, which were morphologically consistent with Acanthamoeba spp. Subsequent electron microscopy and immunofluorescent staining confirmed this impression. She was initially treated with intravenous amphotericin, later changed to voriconazole and caspofungin. Debridement of the sinuses 3 weeks later revealed fungal hyphae but no amebae. Infections with Acanthamoeba have rarely been reported in lung transplantation but have been recognized in bone-marrow and renal transplant patients, and have been lethal in many cases, particularly in patients with immunosuppression due to human immunodeficiency virus infection. More recently, aggressive antimicrobial therapy has resulted in successful outcomes, as discussed herein.
Assuntos
Acanthamoeba/isolamento & purificação , Amebíase/diagnóstico , Amebíase/parasitologia , Transplante de Pulmão/efeitos adversos , Acanthamoeba/ultraestrutura , Animais , Feminino , Humanos , Terapia de Imunossupressão , Microscopia Eletrônica de Transmissão , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: To investigate the effects of oestrogen deficiency on the microarchitecture of trabecular bone in the mandible and the tibia and to test whether they are correlated. METHODS: Twenty-four age-matched Lewis-Brown-Norway female rats underwent surgical intervention either to remove ovaries (ovariectomy, n=12) or to create a complementary control group (sham-operated, n=12). Sixteen weeks later, the animals were sacrificed and the left side of the mandibles and the tibias were scanned with high resolution micro-CT (15 micro m). Multiple morphological measures including the ratio of bone volume/tissue volume, trabecular thickness, trabecular separation and structure model index were obtained from the experimental and control groups. RESULTS: Ovariectomy significantly decreased the ratio of bone volume/soft tissue volume and trabecular thickness, whilst significantly increasing trabecular separation and structure model index in the mandible (P<0.005) and the tibia (P<0.005). There were significant positive correlations between the mandible and the tibia for trabecular separation (r=0.68, P<0.01) and structure model index (r=0.60, P<0.01). CONCLUSIONS: Oestrogen deficiency results in microarchitectural alterations of trabecular bone in both the mandible and the tibia within 16 weeks. The size of marrow spaces and the shape of trabeculae in the mandible correlate with osteoporotic changes in the long bone.
Assuntos
Estrogênios/deficiência , Mandíbula/diagnóstico por imagem , Tíbia/diagnóstico por imagem , Animais , Densidade Óssea , Medula Óssea/diagnóstico por imagem , Medula Óssea/ultraestrutura , Feminino , Lâmina de Crescimento/diagnóstico por imagem , Lâmina de Crescimento/ultraestrutura , Mandíbula/ultraestrutura , Osteoporose/diagnóstico por imagem , Osteoporose/patologia , Ovariectomia , Ratos , Ratos Endogâmicos BN , Ratos Endogâmicos Lew , Estatísticas não Paramétricas , Tíbia/ultraestrutura , Fatores de Tempo , Tomografia Computadorizada por Raios X/métodosRESUMO
Intrathymic (IT) or portal venous (PV) injection of donor antigens has been shown to prolong organ acceptance in low responder rat strain combinations. We determined whether a combination of these strategies would prolong cardiac allograft survival in high responder combinations. Wistar Furth rats received 1 x 10(8) ACI rat bone marrow cells (BMCs) via IT, intravenous (IV), PV, IV + PV, IT + IV or IT + PV route at the time of ACI cardiac transplantation. Without tacrolimus (FK), all grafts were acutely rejected. With FK immunosuppression (1.5 mg/kg per day, I. M., days 0-4), single BMC injection did not increase graft survival beyond 93 days, whereas 70% of grafts survived indefinitely ( > 150 days) when IT and PV BMCs were combined. Animals receiving IT and PV BMCs also had less allograft vasculopathy. Thus, IT and PV injections of donor BMCs under a brief course of FK synergistically improve cardiac allograft survival.
Assuntos
Transplante de Medula Óssea , Sobrevivência de Enxerto/imunologia , Transplante de Coração/imunologia , Imunossupressores/uso terapêutico , Tacrolimo/uso terapêutico , Animais , Terapia de Imunossupressão/métodos , Masculino , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos WF , Fatores de Tempo , Transplante HomólogoRESUMO
BACKGROUND: We determined whether a nontoxic CTLA4-Ig-based conditioning regimen effected mixed chimerism and donor-specific tolerance when heart and bone marrow were transplanted simultaneously. METHODS: Fully mismatched rat strain combinations were used. Recipients received total-body irradiation (300 centigrays), bone marrow (10(8) cells), and cardiac transplants from the donor on day 0. Subsequently, recipient animals received CTLA4-Ig (2 mg/kg, every other day, x 5 doses), tacrolimus (1 mg/kg/day; days 0 to 9), and one dose (10 mg) of antilymphocyte serum on day 10. RESULTS: All bone marrow recipients (n = 7) developed mixed chimerism (mean = 25% +/- 9% at 1 year) and accepted cardiac allografts permanently (> 375 +/- 32 days). Recipients that received conditioning regimen but no bone marrow (n = 5) rejected donor hearts within 51 +/- 13 days (p < 0.01). Recipients that accepted heart grafts also permanently accepted (> 180 days) donor-specific skin grafts, but rapidly rejected (< 10 days) third-party skin grafts. CONCLUSIONS: A nontoxic CTLA4-Ig-based conditioning regimen effects mixed chimerism and donor-specific tolerance when heart and bone marrow are transplanted simultaneously. This regimen may have clinical application.
Assuntos
Antígenos de Diferenciação/farmacologia , Transplante de Medula Óssea/imunologia , Transplante de Coração/imunologia , Imunoconjugados , Quimeras de Transplante/imunologia , Tolerância ao Transplante/imunologia , Abatacepte , Animais , Antígenos CD , Soro Antilinfocitário/farmacologia , Antígeno CTLA-4 , Sobrevivência de Enxerto/imunologia , Humanos , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos WF , Transplante de Pele/imunologiaRESUMO
[structure: see text]. A new fluorescent chemosensor for Cu2+ ions was synthesized by modifying the tripeptide glycyl-histidyl-lysine (GHK) with 9-carbonylanthracene via the standard Fmoc solid-phase peptide synthesis method. While significant fluorescence quenching was observed from the molecule upon binding with Cu2+, addition of Fe2+, Co2+, Ni2+, and Zn2+ to the peptide solution caused a minimum fluorescence emission spectral change, indicating a high specificity of this chemosensor for Cu2+ ions. Effects of pH were also investigated.
Assuntos
Técnicas Biossensoriais , Cobre/análise , Oligopeptídeos/química , Antracenos/síntese química , Fluorescência , Concentração de Íons de Hidrogênio , Metais Pesados/análise , Sensibilidade e Especificidade , Espectrometria de FluorescênciaRESUMO
[reaction: see text] The aldol addition of a chiral ethyl ketone enolate bearing an oxygen substituent (OTBS) at the alpha-position proceeds with high internal and relative diastereoselectivities with various achiral aldehydes in good yields. The profound influence of the resident stereogenic center allows for the use of an achiral catalyst, such as HMPA, with minor attenuation in internal stereoselectivity.
Assuntos
Transplante de Coração/imunologia , Transplante de Coração/normas , Imunossupressores/administração & dosagem , Guias de Prática Clínica como Assunto , Tacrolimo/administração & dosagem , Ensaios Clínicos como Assunto , Ciclosporina/administração & dosagem , Ciclosporina/efeitos adversos , Relação Dose-Resposta a Droga , Incompatibilidade de Medicamentos , Interações Medicamentosas , Monitoramento de Medicamentos/normas , Quimioterapia Combinada , Rejeição de Enxerto/tratamento farmacológico , Humanos , Imunossupressores/efeitos adversos , Imunossupressores/sangue , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/sangue , Ácido Micofenólico/uso terapêutico , Tacrolimo/efeitos adversos , Tacrolimo/sangueRESUMO
BACKGROUND: A multicenter, randomized, controlled, open-label trial was conducted to evaluate the safety and efficacy of Celsior when used for flush and hypothermic storage of donor hearts before transplantation. METHODS: Heart transplant recipients were randomized to one of two treatment groups in which donor hearts were flushed and stored in either Celsior or conventional preservation solution(s) (control). Study subjects were followed for 30 days after transplantation. RESULTS: A total of 131 heart transplant recipients were enrolled (Celsior, n = 64; control, n = 67). The treatment groups were evenly distributed in donor and recipient base line characteristics. Graft loss rate was lower in the Celsior group on day 7 (3% versus 9%) and on day 30 (6% versus 13%), but the difference was not statistically significant based on 95% confidence interval analysis. No significant difference was measured between the Celsior and control groups in 7-day patient survival (97% versus 94%) and the proportion of patients with one or more adverse events (Celsior, 88%; control 87%) or serious adverse events (Celsior, 38%; control, 46%). Significantly fewer patients in the Celsior group developed at least one cardiac-related serious adverse event (13% versus 25%). CONCLUSIONS: Celsior was demonstrated to be as safe and effective as conventional solutions for flush and cold storage of cardiac allografts before transplantation.
Assuntos
Soluções Cardioplégicas , Criopreservação , Dissacarídeos , Eletrólitos , Glutamatos , Glutationa , Transplante de Coração , Histidina , Manitol , Preservação de Órgãos , Adulto , Idoso , Feminino , Seguimentos , Rejeição de Enxerto/mortalidade , Sobrevivência de Enxerto , Humanos , Masculino , Complicações Pós-Operatórias/mortalidade , Transplante HomólogoRESUMO
The toxic dose of irradiation required to achieve stable mixed hematopoietic chimerism is the major limitation to its clinical application in transplantation and other nonmalignant conditions such as hemoglobinopathies. This study examines the additive effect of costimulatory blockage, to our previously described tacrolimus-based conditioning regimen, in further reducing the dose of total-body irradiation to achieve stable mixed chimerism in rats. Fully mismatched, 4- to 6-week-old ACI and Wistar Furth rats were used as donors and recipients, respectively. Recipients were administered CTLA4-Ig 2mg/kg/day (alternate days) in combination with tacrolimus 1 mg/kg/day (daily) from day 0 through day +10, anti-lymphocyte serum 10 mg at day +10 (single dose), and total-body irradiation ranging from 100-600 cGy, prior to bone marrow transplantation (day 0) with 100 x 10(6) of T-cell-depleted bone marrow cells. Levels of donor chimerism were determined over a period of 12 months. The short course of CTLA4-Ig, tacrolimus, and ALS led to dramatic engraftments at reduced doses of irradiation: 100% (5/5) and 93% (13/14) of the animals developed mixed chimerism at 400 cGy and 300 cGy, respectively. At 300 cGy, recipients exhibited durable, multilineage mixed chimerism at 365 days with donor cells ranging from 19-42% (mean 23.4%) with no evidence of graft-vs-host disease. These mixed chimeras exhibited in vitro (mixed lymphocyte reaction) and in vivo (skin grafts) donor-specific tolerance. This study suggests that addition of costimulatory blockade to a tacrolimus-based conditioning regimen reduces the dose of irradiation required to achieve stable multilineage chimerism in rats.
Assuntos
Antígenos de Diferenciação/administração & dosagem , Soro Antilinfocitário/administração & dosagem , Imunoconjugados , Tacrolimo/administração & dosagem , Quimeras de Transplante , Condicionamento Pré-Transplante , Irradiação Corporal Total , Abatacepte , Animais , Antígenos CD , Transplante de Medula Óssea , Antígeno CTLA-4 , Doença Enxerto-Hospedeiro , Células-Tronco Hematopoéticas/imunologia , Tolerância Imunológica , Separação Imunomagnética , Imunossupressores/administração & dosagem , Teste de Cultura Mista de Linfócitos , Doses de Radiação , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos WF , Transplante de Pele/imunologia , Linfócitos TAssuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Cateterismo/instrumentação , Coração Auxiliar/efeitos adversos , Valva Tricúspide/cirurgia , Obstrução do Fluxo Ventricular Externo/cirurgia , Cateterismo/efeitos adversos , Falha de Equipamento , Evolução Fatal , Feminino , Insuficiência Cardíaca/terapia , Humanos , Pessoa de Meia-Idade , Função Ventricular , Obstrução do Fluxo Ventricular Externo/etiologia , Obstrução do Fluxo Ventricular Externo/fisiopatologiaRESUMO
Although systemic administration of NO donors has been shown to attenuate the development of neointimal hyperplasia in the balloon injury model, this strategy has not been tested in a model of allograft vasculopathy. In this study, we investigated the effect of FK409, a spontaneous NO releaser, on the development of allograft vasculopathy, using a rat aortic transplant model. Thoracic aortas from ACI rats were transplanted heterotopically into the abdominal aorta of Wistar-Furth rats. Postoperatively, recipients received FK409 orally every 8 hours from the day of transplantation to the time of euthanization. Morphometric and immunohistochemical analyses were performed on the aortic grafts 8 weeks after transplantation. Control allografts showed severe neointimal hyperplasia, which consists mainly of alpha-actin-containing vascular smooth muscle cells. The FK409-treated allografts showed a dose-dependent reduction (statistically significant compared with the control) in the neointimal thickness as the dose increased from 1 to 10 mg/kg (thrice per day). However, there was no significant difference in the neointimal thickness between groups treated with 10 and with 20 mg/kg. FK409 treatment (10 mg/kg) caused a significant decrease in DNA synthesis (5-bromo-2-deoxyuridine [BrdU] uptake), an increase in DNA fragmentation (terminal deoxynucleotidyltransferase-mediated uridine nick-end labeling [TUNEL]), and upregulation of Fas expression, in the neointimal vascular smooth muscle cells. These data suggest that FK409 attenuates the allograft vasculopathy in a rat aortic transplant model.
Assuntos
Aorta/transplante , Músculo Liso Vascular/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Nitrocompostos/farmacologia , Animais , Aorta/patologia , Apoptose/efeitos dos fármacos , Bromodesoxiuridina/metabolismo , Ciclosporina/farmacologia , Imuno-Histoquímica , Masculino , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos WF , Transplante HomólogoRESUMO
BACKGROUND: Cardiac transplantation has been successfully performed in patients with a history of presumably cured Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). Though the risk of recurrence is a major concern, the long-term influence of prior cancer and cancer therapy on posttransplant outcome has not been previously investigated. METHODS: Questionnaires were sent to 130 cardiac transplant centers in the United States registered with the United Network for Organ Sharing. Data collected included patient demographics; type, stage, and timing of HD/NHL; treatment for HD/NHL; posttransplant immunosuppressive regimen, rejection history, and outcomes; and Epstein-Barr virus status. RESULTS: Thirty-four cardiac transplant recipients with a previous history of HD (n=16) or NHL (n=18) were identified. HD patients averaged 41+/-15 years of age, with a mean disease-free interval of 15+/-9 years at the time of transplantation. NHL patients averaged 42+/-17 years of age with a mean disease-free interval of 10+/-9 years at the time of transplantation. The mean follow-up for the entire group was 50 months (range, 2 days to 136 months), and mean follow-up for the survivors was 67 months (range, 23-136 months). The 1-, 3-, 5-, 7-, and 10-year actuarial survival estimates for the entire group are 77%, 64%, 64%, 64%, and 50%, respectively. Actuarial survival was lower in HD patients (P=0.04) and in patients who had previously undergone splenectomy (P=0.008). Cox regression analysis identified only prior splenectomy (P=0.02) as an independent risk factor for mortality after cardiac transplantation with an adjusted relative risk of 6.2 (1.7-21.9, 95% confidence intervals). CONCLUSIONS: Although the numbers are small, these data strongly suggest that there is an increased mortality risk for cardiac transplant recipients with prior HD who have undergone splenectomy.
Assuntos
Transplante de Coração , Doença de Hodgkin , Linfoma não Hodgkin , Análise Atuarial , Intervalo Livre de Doença , Feminino , Transplante de Coração/mortalidade , Transplante de Coração/fisiologia , Doença de Hodgkin/mortalidade , Doença de Hodgkin/terapia , Humanos , Linfoma não Hodgkin/mortalidade , Linfoma não Hodgkin/terapia , Masculino , Esplenectomia , Inquéritos e Questionários , Análise de Sobrevida , Sobreviventes , Fatores de Tempo , Estados UnidosRESUMO
BACKGROUND: Donor chimerism (the presence of donor cells of bone marrow origin) is present for years after transplantation in recipients of solid organs. In lung recipients, chimerism is associated with a lower incidence of chronic rejection. To augment donor chimerism with the aim to enhance graft acceptance and to reduce immunosuppression, we initiated a trial combining infusion of donor bone marrow with heart transplantation. Reported herein are the intermediate-term results of this ongoing trial. METHODS: Between September 1993 and August 1998, 28 patients received concurrent heart transplantation and infusion of donor bone marrow at 3.0 x 10(8) cells/kg (study group). Twenty-four contemporaneous heart recipients who did not receive bone marrow served as controls. All patients received an immunosuppressive regimen consisting of tacrolimus and steroids. RESULTS: Patient survival was similar between the study and control groups (86% and 87% at 3 years, respectively). However, the proportion of patients free from grade 3A rejection was higher in the study group (64% at 6 months) than in the control group (40%; P =.03). The prevalence of coronary artery disease was similar between the two groups (freedom from disease at 3 years was 78% in study patients and 69% in controls). Similar proportions of study (18%) and control (15%) patients exhibited in vitro evidence of donor-specific hyporesponsiveness. CONCLUSIONS: The infusion of donor bone marrow reduces the rate of acute rejection in heart recipients. Donor bone marrow may play an important role in strategies aiming to enhance the graft acceptance.
Assuntos
Transplante de Medula Óssea , Facilitação Imunológica de Enxerto , Transplante de Coração , Doença Aguda , Transplante de Células , Feminino , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/prevenção & controle , Transplante de Coração/efeitos adversos , Transplante de Coração/imunologia , Transplante de Coração/mortalidade , Antígenos de Histocompatibilidade Classe I/análise , Humanos , Imunossupressores/uso terapêutico , Teste de Cultura Mista de Linfócitos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Quimeras de TransplanteRESUMO
BACKGROUND: We have demonstrated that donor cell chimerism is associated with a lower incidence of obliterative bronchiolitis (OB) in lung recipients, and that donor chimerism is augmented by the infusion of donor bone marrow (BM). We herein report the intermediate results of a trial combining the infusion of donor BM and lung transplantation. METHODS: Clinical and in vitro data of 26 lung recipients receiving concurrent infusion of donor bone marrow (3.0 to 6.0 x 10(8) cells/kg) were compared with those of 13 patients receiving lung transplant alone. RESULTS: Patient survival and freedom from acute rejection were similar between groups. Of the patients whose graft survived greater than 4 months, 5% (1 of 22) of BM and 33% (4 of 12) of control patients, developed histologic evidence of OB (p = 0.04). A higher proportion (but not statistically significant) of BM recipients (7 of 10, 70%) exhibited donor-specific hyporeactivity by mixed lymphocyte reaction assays as compared with the controls (2 of 7, 28%). CONCLUSIONS: Infusion of donor BM at the time of lung transplantation is safe, and is associated with recipients' immune modulation and a lower rate of obliterative bronchiolitis.
Assuntos
Transplante de Medula Óssea/imunologia , Transplante de Pulmão/imunologia , Quimeras de Transplante , Adulto , Bronquiolite Obliterante/etiologia , Feminino , Rejeição de Enxerto , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Análise de SobrevidaRESUMO
BACKGROUND: In heterotopic heart transplantation, the donor heart is connected parallel to the recipient's diseased heart. Recipients continue to have risks, such as arrhythmia, thromboembolism, valvular heart disease, and ischemic heart disease which can develop in the native heart. It may serve as a clinical model to study long-term pathophysiologic processes in the native heart of patients with a left ventricular assist device. METHOD: We analyzed the prevalence of long-term complications related to the native heart in the heterotopic heart transplant and attempted to gain insight into the potential risk to a native heart after receiving a left ventricular assist device. RESULTS: Between December 1984 and December 1994, 16 patients (13 men, 3 women, ranging in age from 37 to 60 years) underwent heterotopic heart transplant at the University of Pittsburgh. The 1- and 5-year survival rate after the transplant was 81% and 44%, respectively. Actuarial freedom from complications related to the native heart after 1 year and 4 years was ventricular arrhythmia: 85%, 75%; ischemic disease: 85%, 64%; valvular disease: 100%, 88%; and thromboembolism: 85%, 58%. Of these complications, thromboembolism was not considered in determining actuarial freedom from complications because thromboembolism should be regarded as a device-related complication rather than as a native-heart-related complication for left ventricular assist device recipients. Consequently, actuarial freedom from all complications excluding thromboembolism was 70% after 1 year and 50% after 4 years. In addition, the hazard function curve remains constant up to 80 months after the operation without significant differences among the yearly ratios. CONCLUSIONS: This analysis suggests that cautious observation of the native heart's long-term performance is necessary for the left ventricular assist device recipient.
Assuntos
Transplante de Coração , Coração Auxiliar/efeitos adversos , Taquicardia Ventricular/etiologia , Tromboembolia/etiologia , Transplante Heterotópico , Adulto , Cateterismo Cardíaco , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Taquicardia Ventricular/epidemiologia , Taquicardia Ventricular/fisiopatologia , Tromboembolia/epidemiologia , Tromboembolia/fisiopatologia , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Mixed allogeneic bone marrow chimerism induces tolerance to solid organ grafts. Although we previously reported that partially ablative conditioning with 700 cGy of total body irradiation (TBI) is sufficient to allow for bone marrow engraftment in mice, we determined that a minimum of 1000 cGy was required in the rat. Because T cells and NK cells are critical in bone marrow graft rejection, our purpose was to examine whether targeting of radioresistant NK cells and/or T cells in the recipient hematopoietic microenvironment would reduce the TBI dose required for engraftment of allogeneic rat bone marrow. METHODS: Wistar Furth rats received either anti-NK3.2.3 monoclonal antibodies on days -3 and -2, anti-lymphocyte serum on day -5, a combination of both or no pretreatment. TBI was performed on day 0 and rats were reconstituted with 100x10(6) T cell-depleted bone marrow cells from ACI donors. RESULTS: Engraftment of T cell-depleted rat bone marrow was readily achieved in animals conditioned with 1000 cGy TBI alone (12/12) and the level of donor chimerism averaged 89%. At 900 cGy TBI alone only one of eight recipients engrafted. In striking contrast, 11 of 12 animals pretreated with anti-NK monoclonal antibodies and irradiated with 900 cGy showed donor chimerism at a mean level of 41%. No further enhancement of bone marrow engraftment could be achieved when recipients were pretreated with antilymphocyte serum alone or antilymphocyte serum plus anti-NK monoclonal antibodies. Mixed allogeneic chimeras exhibited stable multilineage chimerism and donor-specific tolerance to subsequent cardiac allografts. CONCLUSION: Specific targeting of radioresistant host NK cells allows for a significant reduction of the TBI dose required for allogeneic bone marrow engraftment.
Assuntos
Quimeras de Transplante/imunologia , Condicionamento Pré-Transplante/métodos , Animais , Anticorpos Monoclonais/farmacologia , Soro Antilinfocitário/farmacologia , Transplante de Medula Óssea/imunologia , Transplante de Medula Óssea/fisiologia , Rejeição de Enxerto/patologia , Doença Enxerto-Hospedeiro/prevenção & controle , Transplante de Coração/imunologia , Tolerância Imunológica , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/fisiologia , Células Matadoras Naturais/efeitos da radiação , Cinética , Depleção Linfocítica , Masculino , Camundongos , Ratos , Ratos Endogâmicos ACI , Ratos Endogâmicos WF , Irradiação Corporal TotalRESUMO
BACKGROUND: Mixed hematopoietic chimerism has been shown to induce long-term acceptance of transplant organs. We determined whether mixed chimerism prevented allograft vasculopathy, using the rat aortic allograft model. METHODS: Mixed chimeras were prepared by reconstituting lethally irradiated (1100 cGy) WF rats with a mixture of T-cell depleted (TCD) syngeneic (WF) plus TCD allogeneic (ACI) bone marrow. Donor-specific (ACI) or third-party (F344) aortic grafts were transplanted into mixed chimeric animals 1 to 2 months after bone marrow reconstitution. No immunosuppressive drugs were administered. At 30 days postoperatively, aortic allografts were harvested for histology and measurement of cytokine mRNA by semiquantitative RT-PCR. Some aortic grafts were harvested at 90 and 180 days after transplantation for histological analysis. The degree of intimal hyperplasia and cytokine gene expression were compared among 4 groups: I (syngeneic; ACI donors to ACI recipients), II (allografts; ACI to WF), III (donor specific; ACI donor to chimeras) and IV (third-party; F344 to chimeras). RESULTS: There was no difference in the degree of intimal hyperplasia (IH) between groups I and III. Groups II and IV had significantly more IH than group I. Compared to group I, levels of mRNA for IFN-y, IL-2, IL-10 and iNOS in groups II and IV were higher, while there was no difference in mRNA levels between group I and III. CONCLUSIONS: These data suggest that mixed chimerism prevents allograft vasculopathy. Mixed chimerism holds great promise in clinical transplantation as a means to prevent allograft vasculopathy.