Comparison of gene expression profiles in a porcine infarct model after intracoronary, transthoracic, or transendocardiac injection of heterologous bone marrow mesenchymal cells.

An in vivo porcine model of myocardial infarction was developed with the aim of comparing the effectiveness for cardiac repair of intracoronary, transthoracic, or transendocardial delivery strategies for bone marrow mesenchymal stem cells (BMMSC) using an analysis of expression levels of transcripts related to various cellular processes at 8 heart regions using quantitative reverse transcriptase polymerase chain reaction. We observed significant rises in cardiomyogenic markers Mef2C, Gata4 and Nkx2.5, and contractibility marker Serca2A at infarcted regions for cell-treated pigs. We also observed differences in Sdf1 expression related to the organ stress response between delivery strategies. Unexpectedly, increased expression of Col1A1 was detected in 2 cell-treated groups at various heart regions. Our results suggest improvements in both contractility and cardiomyogenic capability of damaged tissue after BMMSC injection, but also warned us about the relevance of the chosen delivery strategy and potential undesired effects like increasing fibrosis after treatment.

[Renal xenotransplant. Acute vascular rejection]. / Xenotrasplante renal. El rechazo vascular agudo.

INTRODUCTION AND OBJECTIVES: Organ transplant is nowadays a usual and succesful practice, although with limited application due to the lack of organs. Yearly thousands of patients get access to the waiting list and finally will death while they are waiting for an organ. In the U.S.A., 2005 waiting list for kidneys, heart, liver lung and pancreas was around 94.419. Number of transplants performed was 27.966 and died patients while waiting for an organ, 41.392 (1). Pig xenotransplant is one of the possibilities to ameliorate the lack of organs for transplant. Arrangement of pigs with different genetic modifications generated great expectatives on the use of these organs in clinics. Although preclinical experimental studies with kidneys reached prolonged survivals, these are really insufficient to go on with the clinical appliance. Hyperacute rejection produces destruction of the organ immediately. This problem could be pharmacologically precluded in xeno-transplant. However, acute rejection or vascular rejection usually produces the lost of the implant. New inmunosuppresive schedules delay significantly rejection, but not definitively. Xenotransplant as a therapeutic option introduces important scientific problems, as well as ethical and social. This paper reports a summary of our experience in renal xenotransplant and the management of acute rejection. MATERIAL AND METHODS: Twenty xenotransplants from transgenic pig (hDAF) as donor to babuine as receptor. Average weight of the animals ranged 11.4-75 kgrs and babuines 10-26 kg. Xenograft average weight ranged 39-160 grs. Implant was performed to aorta and cava. Four inmunosupressive schedules were used. RESULTS: Average survival was 7-9 days. Final Histological findings are described. Changes observed were secondary to acute tubular necrosis mixed with changes due to acute rejection. Three grafts were lost due to technical major problems. CONCLUSIONS: Although we have observed some promising results, xenotransplant is a very difficult problem to solve in the long-term. A lot of research is still needed-.

Xenotrasplante renal. El rechazo vascular agudo / Renal xenotransplant. Acute vascular rejection

Introducción y objetivos: El trasplante de órganos es hoy una práctica habitual y de éxito, pero de aplicación limitada, debido a la insuficiencia de órganos. Anualmente miles de pacientes en lista de espera fallecen, esperando un órgano. En EEUU en el 2005 la lista de espera para trasplantes de órganos, riñón, corazón, hígado, pulmón, páncreas era de 94.419. El número de trasplantes realizados fue de 27.966 y el de fallecidos esperando un órgano 41.392. (1) El xenotrasplante de órganos de cerdo es una de las esperanzas para aliviar la falta de órganos para el trasplante. La disponibilidad de cerdos con distintas modificaciones genéticas, creó grandes expectativas sobre una pronta utilización clínica de los mismos, sin embargo, aunque los estudios experimentales preclínicos con el riñón han alcanzado supervivencias prolongadas, estas son insuficientes para dar el paso a la fase clínica. El rechazo hiperagudo (RH) con destrucción del órgano de forma inmediata, habitual en el trasplante de órganos entre especies distintas filogenéticamente (trasplante discordante) puede en la actualidad ser evitado sin embargo, la aparición de un posterior rechazo humoral agudo (RHA) también llamado rechazo vascular agudo (RVA) o xenorechazo agudo retardado, da lugar al fracaso del xenotrasplante. La utilización de distintas pautas de inmunosupresión han conseguido retrasar de forma significativa este rechazo, pero no lo previenen de forma sistemática. El xenotrasplante como opción terapéutica plantea importantes problemas científicos, éticos y sociales. En este artículo exponemos un resumen de nuestra experiencia en xenotrasplante renal y comentamos los problemas del RVA. Material y método: Se han practicado 20 xenotrasplantes renales de cerdo transgénico hDAF (donante) a babuino (receptor). El peso de los cerdos osciló entre 11,400 y 75 kg. y el de los babuinos entre 10 y 26,500 kg. El peso del xenoinjerto, riñón del cerdo, osciló entre 39 y 160 g. Resultados: La supervivencia media de los animales estuvo entre 7-9 días. El estudio histológico final de los injertos mostró cambios secundarios a necrosis tubular aguda mezclados con alteraciones propias de rechazo agudo. Tres injertos se perdieron por problemas técnicos mayores. Conclusiones: Aunque hemos observado resultados prometedores, el xenotrasplante es una cuestión de gran dificultad, especialmente a largo plazo. Se precisa aún en la actualidad de mucha actividad investigadora en este campo

Introduction and objectives: Organ transplant is nowadays a usual and succesful practice, although with limited application due to the lack of organs. Yearly thousands of patients get access to the waiting list and finally will death while they are waiting for an organ. In USA, 2005 waiting list for kidneys, heart, liver lung and pancreas was around 94.419. Number of transplants performed was 27.966 and died patients while waiting for an organ, 41.392 (1). Pig xenotransplant is one of the possibilities to ameliorate the lack of organs for transplant. Arrangement of pigs with different genetic modifications generated great expectatives on the use of these organs in clinics. Although preclinical experimental studies with kidneys reached prolonged survivals, these are really insufficient to go on with the clinical appliance. Hyperacute rejection produces destruction of the organ immediately. This problem could be pharmacologically precluded in xenotransplant. However, acute rejection or vascular rejection usually produces the lost of the implant. New inmunosuppresive schedules delay significantly rejection, but not definitively. Xenotransplant as a therapeutic option introduces important scientific problems, as well as ethical and social. This paper reports a summary of our experience in renal xenotransplant and the management of acute rejection. Material and methods: Twenty xenotransplants from transgenic pig (hDAF) as donor to babuine as receptor. Average weight of the animals ranged 11.4-75 kgrs and babuines 10-26 kg. Xenograft average weight ranged 39-160 grs. Implant was performed to aorta and cava. Four inmunosupressive schedules were used. Results: Average survival was 7-9 days. Final Histological findings are described. Changes observed were secondary to acute tubular necrosis mixed with changes due to acute rejection. Three grafts were lost due to technical major problems. Conclusions: Although we have observed some promising results, xenotransplant is a very difficult problem to solve in the long-term. A lot of research is still needed

Flow cytometry complement-mediated cytotoxicity assay detects baboon xenoantibodies directed to porcine epitopes undetected by hemolytic assay.

The pig-to-primate model is increasingly being utilized as the final preclinical means of assessing therapeutic strategies aimed at allowing discordant xenotransplantation. To obtain information about the nature of cytotoxic response in pig-to-baboon xenotransplants, we sought to determine if serum cytotoxicity in this model was assay dependent. Sera from nine kidney or heart xenotransplanted baboons were obtained before transplantation and at the time of acute humoral xenograft rejection (AHXR). Cytotoxicity was measured by an anti-pig haemolytic assay (APHA) and by a flow cytometry complement-dependent assay (FCCA), using pig blood lymphocytes (PBLs). Serum samples showing inter-assay differences were absorbed with pig erythrocytes and assayed by APHA and FCCA, as well as by measuring anti-alphaGal and total anti-pig xenoantibodies. The results showed that in four AHXR samples, FCCA cytotoxicity was higher than APHA cytotoxicity. Absorption with pig erythrocytes diminished FCCA and removed APHA cytotoxicity. Residual FCCA activity was due to total anti-pig and IgM anti-alphaGal and non-Gal antibodies. Our results indicate that some cytotoxic antibodies present in the sera of xenotransplanted baboons at time of AHXR are IgM antibodies directed against pig PBL antigens not detected by APHA.

[Renal xenotransplantation from hDAF pig to baboon. Experience and review]. / Xenotrasplante renal cerdo hDAF-babuino. Experiencia y revisión.

UNLABELLED: The renal xenotransplant could be the solution on the demand of organs for transplantation. We present here our experience and review the actual status of the xenotransplant. METHODS: We have done 20 xenotransplants from transgenic pig h DAF to baboons, with four protocols of immunosuppression. All the hosts were treated with GAS 914. Group A: Cyclophosphamide, Cyclosporine, Mycophenolate, and Steroids (n = 10). Group B: Cyclophosphamide, Cyclosporine, FTY 720, and Steroids (n = 3). Group C: Basiliximab, Cyclosporine, Mycophenolate, and Steroids (n = 3). Group D: Basiliximab, FTY 720, Everolymus, and Steroids (n = 4). RESULTS: The duration of the xenografts ranged between 1 and 31 days. The function of the xenografts in relation to the type of immunosuppression were not significantly different: A) 7 days, B) 8 days, C) 8 days, and D) 9 days. CONCLUSIONS: 1. The cold ischemic time of the graft, has influence in the initial function of the kidneys but not in the evolution and duration of the graft. 2. The hyperacute rejection has been overcome with the utilization of transgenic pigs. The graft failure was due to acute humoral rejection that was not aborted by the actual inmunosupressors. 3. It is necessary to develop new immunosuppression protocols, through new knowledge of their pharmacology and the physiology of the xenografts, and at the same time it is important to avoid the potential risk of transmission of animal infections.

Xenotrasplante renal cerdo hDAF-babuino. Experiencia y revisión / Renal xenotrasplantation of HDAF pig to baboons. Experience and review

INTRODUCCIÓN: El xenotrasplante renal puede representar la solución a la creciente demanda de órganos. Presentamos nuestra experiencia y revisamos el estado actual del xenotrasplante. MATERIAL Y MÉTODO: Hemos realizado 20 xenotrasplantes de riñón de cerdo transgénico hDAF a babuino con cuatro protocolos de inmunosupresión. Todos los receptores recibieron GAS 914.Grupo A: Ciclofosfamida, Ciclosporina, Micofenolato y Corticosteroides (n=10).Grupo B: Ciclofosfamida, Ciclosporina, FTY 720 y Corticosteroides (n=3).Grupo C: Basiliximab, Ciclosporina, FTY 720 y Corticosteroides (n=3).Grupo D: Basiliximab, FTY 720, Everolimus y Corticosteroides (n=4). RESULTADOS: La supervivencia de los xenoinjertos osciló entre 1 y 31 días. La supervivencia en relación con los protocolos de inmunosupresión no fue significativamente diferente: A) 7 días, B) 8días, C) 8 días, D) 9 días. CONCLUSIONES: 1. Los tiempos de isquemia fría influyen en la función inicial de los riñones, no en su evolución final. 2. El rechazo hiperagudo ha sido superado con la utilización de cerdos transgénicos, produciéndose el fracaso por rechazo humoral agudo, no controlado con los protocolos de inmunosupresión actuales. 3. Es preciso investigar y desarrollar otros protocolos de inmunosupresión que nos permitan un mejor conocimiento de la fisiología del xenoinjerto y de su potencial riesgo de transmisión de enfermedades (AU)

SUMMARY: The renal xenotrasplant could be the solution on the demand of organs for transplantation. We present here our experience and review the actual status of the xenotransplant. METHODS: We have done 20 xenotransplants from transgenic pig h DAF to baboons, with four protocols of inmunosupression. All the hosts were treated with GAS 914.Group A: Cyclophosphamide, Cyclosporine, Mycophenolate, and Steroids (n=10).Group B: Cyclophosphamide, Cyclosporine, FTY 720, and Steroids (n=3). Group C: Basiliximab, Cyclosporine, Mycophenolate, and Steroids (n=3). Group D: Basiliximab, FTY 720, Everolymus, and Steroids (n=4). RESULTS: The duration of the xenografts ranged between 1 and 31 days. The function of the xenografts in relation to the type of inmunosupression were not significantly different: A) 7 days, B) 8 days, C) 8 days, and D) 9 days. CONCLUSIONS: 1. The cold ischemic time of the graft, has influence in the initial function of the kidneys but not in the evolution and duration of the graft. 2. The hyperacute rejection has been overcome with the utilization of transgenic pigs. The graft failure was due to acute humoral rejection that was not aborted by the actual inmunosupressors. 3. It is necessary to develop new inmunosupression protocols, through new knowledge of their pharmacology and the physiology of the xenografts, and at the same time it is important to avoid the potential risk of transmission of animal infections (AU)

Porcine endothelial cell activation in hDAF pig hearts transplanted in baboons with prolonged survival and lack of rejection.

Depletion of anti-alphaGal antibodies before and after transplantation with GAS 914, a polylysine containing alphaGal epitopes, together with immunosuppression, has been shown to prevent acute humoral xenograft rejection (AHXR) in hDAF pig-to-baboon xenotransplantation. This therapy was associated with low levels of serum anti-alphaGal antibodies and lack of antipig hemolytic antibodies (APA) during the entire transplant course. In the present study we investigated the condition of xenograft endothelial cells and the presence of other antipig antibodies. No xenograft failed because of AHXR. However, endothelial cell markers of activation, such as CD62, CD106, ET-1, and particularly 5A6/8, were detected at necropsy, along with a lack or scarce deposits of IgM and total absence of complement and fibrin. The endothelial cell markers were negative or slightly positive at biopsy obtained 30 minutes after transplantation. At the time of animal death serum xenoantibodies against pig aortic cells were also detected by immunochemistry whereas anti-alphaGal and APHA were almost absent, suggesting that the presence of non-anti-alphaGal and noncytotoxic xenoantibodies may cause endothelial activation.

Elicited non-anti-alphaGAL antibodies may cause acute humoral rejection of hDAF pig organs transplanted in baboons.

The combination of immunosuppression and GAS 914, a polylysine containing alphaGal trisaccharide type 2 (TRI 2), has been associated with the prevention of acute humoral xenograft rejection (AHXR) in human decay accelerating factor (hDAF) pig-to-baboon xenotransplants. The aim of this study was to investigate the role of immunosuppression and GAS 914 to neutralize xenoantibodies before and after xenotransplantation. Eight baboons underwent heteropic heart xenotransplantation with hDAF transgenic pig organs, receiving GAS 914 before and after transplantation. Six baboons (Group A) were treated with an immunosuppression protocol that included cyclophosphamide (CyP), Neoral, ERL, and steroids. The other 2 baboons (Group B) were treated with the same immunosuppression but with a 50% reduction in the doses of CyP. No xenograft from Group A underwent acute humoral xenograft (median survival, 27 days), whereas the 2 in Group B experienced rejection (median survival, 6 days). GAS 914 depleted both immunoglobulin (Ig)M and IgG anti-alphaGAL disaccharide (DI), trisaccharide type 2 (TRI 2), and trisaccharide type 6 (TRI 6), before and after transplantation in Groups A and B. However, cytotoxic antibodies with other anti-pig specificities were elicited by the xenografts in Group B leading to AHXR.

Removal of bowel aerobic gram-negative bacteria is more effective than immunosuppression with cyclophosphamide and steroids to decrease natural alpha-galactosyl IgG antibodies.

Natural alpha-Galactosyl (Gal) antibodies play an important role in the rejection of pig xenografts by humans and Old World monkeys. In this study we investigate the efficacy of two different strategies to reduce the serum level of natural anti-Gal antibodies. On the one hand, removal of aerobic gram-negative bacteria from the intestinal flora, because anti-Gal antibodies appear to be produced as a result of the continuous sensitization by these microorganisms. On the other hand, we studied the effect on these antibodies of an immunosuppressive regimen of cyclophosphamide and steroids. Ten baboons were treated for three months with norfloxacin (Nor Group; n=6) or cyclophosphamide and steroids (CyP Group; n=4). A further four baboons did not receive any treatment (Control Group). Aerobic gram-negative bacteria became negative in stools of the Nor Group after two weeks of treatment, and remained undetectable until week 7. Thereafter, a gradual increase on the fecal concentration of aerobic gram-negative bacteria was observed despite the norfloxacin treatment. The mean anti-Gal IgG in the Nor Group gradually declined from week 4 to 9 to a mean of 62.7 +/- 18% of the baseline level, and during this period were significantly lower than in the CyP (P<0.02) and the Control (P<0.05) groups. No differences were observed between the three groups during the 16 weeks of follow-up in serum levels of anti-Gal IgM, hemolytic anti-pig antibodies, total IgG, IgM and IgA. In conclusion, removal of normal aerobic gram-negative bacteria from the intestinal flora is more effective than immunosuppression with CyP and steroids in reducing the level of natural anti-Gal antibodies, although there is no discernible effect on IgM antibodies.