The impact of topically applied preservation solutions on the respiratory epithelium of tracheal grafts submitted to cold ischemia: functional and morphological analysis

OBJECTIVE: Advances in graft reepithelialization and revascularization have renewed interest in airway transplantation. This study aims to determine whether topically applied preservation solutions can ameliorate ischemic injury to tracheal grafts. We analyzed 1) the effects of cold ischemia on the mucociliary clearance of tracheal grafts and 2) the impact of topically applied preservation solutions on the effects of cold ischemia on mucociliary clearance. METHOD: Tracheal segments (n=217) from 109 male Wistar rats were harvested, submerged in low-potassium-dextran-glucose, histidine-tryptophan-ketoglutarate, or saline solution (saline group), and stored at 4°C for 6, 10, 16, or 24 hours. A control group (not submerged) was analyzed immediately after harvesting. In situ mucociliary transport and ciliary beating frequency were measured using a stroboscope. Epithelial integrity, cellular infiltration, and mucus storage were quantified by light microscopy and image analysis software, along with transmission electron microscopy. RESULTS: 1) The effects of cold ischemia: in situ mucociliary transport and ciliary beating frequency were greater in the control group than after cold ischemia. Microscopic analysis results were similar between groups. 2) The effects of preservation solutions: there was no difference between the low-potassium-dextran-glucose, histidine-tryptophan-ketoglutarate, and saline groups in functional or light microscopy analysis. The saline group presented stronger signs of ischemic injury with transmission electron microscopy. CONCLUSIONS: Cold ischemia diminished the mucociliary clearance of the tracheal respiratory epithelium. Topically applied preservation solutions did not ameliorate the injury caused by cold ischemia to the tracheal respiratory epithelium. .

Long-Term (Postnatal Day 70) Outcome and Safety of Intratracheal Transplantation of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Neonatal Hyperoxic Lung Injury

PURPOSE: This study was performed to evaluate the long-term effects and safety of intratracheal (IT) transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in neonatal hyperoxic lung injury at postnatal day (P)70 in a rat model. MATERIALS AND METHODS: Newborn Sprague Dawley rat pups were subjected to 14 days of hyperoxia (90% oxygen) within 10 hours after birth and allowed to recover at room air until sacrificed at P70. In the transplantation groups, hUCB-MSCs (5x10(5)) were administered intratracheally at P5. At P70, various organs including the heart, lung, liver, and spleen were histologically examined, and the harvested lungs were assessed for morphometric analyses of alveolarization. ED-1, von Willebrand factor, and human-specific nuclear mitotic apparatus protein (NuMA) staining in the lungs and the hematologic profile of blood were evaluated. RESULTS: Impaired alveolar and vascular growth, which evidenced by an increased mean linear intercept and decreased amount of von Willebrand factor, respectively, and the hyperoxia-induced inflammatory responses, as evidenced by inflammatory foci and ED-1 positive alveolar macrophages, were attenuated in the P70 rat lungs by IT transplantation of hUCB-MSCs. Although rare, donor cells with human specific NuMA staining were persistently present in the P70 rat lungs. There were no gross or microscopic abnormal findings in the heart, liver, or spleen, related to the MSCs transplantation. CONCLUSION: The protective and beneficial effects of IT transplantation of hUCB-MSCs in neonatal hyperoxic lung injuries were sustained for a prolonged recovery period without any long-term adverse effects up to P70.

Evaluation of propofol as an anesthetic in swine tracheal transplant surgery / Evaluación del propofol como anestésico para cerdos sometidosa trasplante de tráquea

Because the swine have been used as an ideal animal model for different medical investigations, it has been useful to the advance in vital organs transplant field. The trachea transplant is a surgical procedure which requires special conditions in anesthetic depth and muscular relax, for a long period, and in addition, an excellent intra and post-operatory analgesic. The aim of this study was to use a combination of xylacine and ketamine, as premedication and evaluate propofol as a general anesthetic in trachea transplant donor or recipient pigs. All the methodology was under the approval of the Committee of Ethics for the Experimentation with Animals of the University of Antioquia. Ten donors and 10 recipients female Yorkshire pigs having a body weight of about 30 kg were used. Trachea extraction from a donor and its transplantation to a recipient in the same surgical procedure was performed. The average body weight (PP) was 30 ± 2.92 kg for both the groups, the average value were as follows: time of recumbency (TR) 8.25 ± 2:85 min; latency period (PL) 6.05 ± 1.73 min, (for both groups); surgical time (TQ) for donors and recipients was 80 ± 0.02, and 247 ± 0.02 min, respectively; heartbeat rate (FC) 90.34 ± 8.14 bpm, O2 saturation (SO2) 95.47 ± 1.79 %; exhaled PCO2 31.13 ± 1.89 mmHg; temperature (T) for both groups was 37.51 ± 0.74oC. The mean arterial pressure average (PAM) for both group was 65.47 ± 5.94 mmHg; the average time of esternal recumbecency (TRE) for donor female pigs was 16.50 ± 4.09 min, and the average time to stand up (TP) for swine recipients was 30.70 + 3.27 min. These results indicate that Propofol can be considered as a safe anesthetic for use in continuous perfusion. Since it has not an analgesic effect it is strongly recommended to combine it with opioids during anesthetic-surgical procedures; it can be also used with neuromuscular preanesthetics or inhaled anesthetics.

Los cerdos se han utilizado como modelo animal ideal para diversas investigaciones médicas; han sido útiles para el avance en el trasplante de órganos. El trasplante de tráquea es un procedimiento quirúrgico que requiere condiciones especiales en profundidad anestésica y relajación muscular por un período largo, y además, una analgesia intra y del postoperatoria excelente. Nuestra investigación utiliza una combinación de xylacine y ketamina, como premedicación y evaluar el propofol como anestésico general en cerdos donantes y receptores en quienes el trasplante de la tráquea sería hecho. Toda la metodología contó con la aprobación del Comité de Ética para la Experimentación con los Animales de la Universidad de Antioquia. Utilizamos 10 donantes y 10 cerdos raza Yorkshire hembras con un peso corporal de cerca de 30 kilogramos. Se realizó la extracción de la tráquea de un donante y el trasplante a un receptor en el mismo procedimiento quirúrgico. El peso corporal (PP) fue de 30 ± 2.92 kg para todo el grupo, el tiempo de recumbencia (TR) para ambos grupos fue de 8.25 ± 2.85 min, el período de latencia (PL) para ambos grupos fue de 6.05 ± 1.73 min, el promedio de tiempo quirúrgico (TQ) para los donantes fue de 80 min ± 0.02, el TQ de los receptores fue de  247m ± 0.02. La presión arterial media (PAM) para todo el grupo fue de 65.47 ± 5.94 mmHg, el promedio de frecuencia cardiaca (FC) para ambos grupos fue de 90.34 ± 8.14 ppm, el promedio de saturación de oxigeno (SO2) fue de 95.47 ± el 1.79% y el CO2 espirado fue de 31.13 ± 1.89 mmHg y el promedio de la temperatura (t) para ambos grupos fue de  37.51 ± 0.74oC. La tiempo de recumbencia esternal (TRE) para las cerdas donantes fue de 16.50 ± 4.09 min y el tiempo para pararse (TP) para los receptores fue de 30.70 ± 3.27 min. El propofol se puede considerar como anestésico seguro para el uso en la perfusión continua durante la anestesia. Puesto que no tiene un efecto analgésico se recomienda combinarlo con opioides.

Manejo de la vía aérea en trasplante de tráquea / Managing of the airway in transplant of trachea

A pesar de los grandes avances en cirugía de resección traqueal y en dispositivos como las endoprótesis, existen pacientes en quienes dichas técnicas no son viables debido al compromiso tan extenso de su estenosis; por lo tanto, su problema no se ha podido resolver alterando la calidad de vida y muchas veces poniendo en riesgo la vida de los pacientes, secundario a una obstrucción de la vía aérea. A continuación, se describe la experiencia del grupo de la Universidad de Antioquia y el Hospital Universitario San Vicente de Paúl, en el manejo de la vía aérea durante el transplante de tráquea realizado a 5 pacientes en la institución, ya que dicho procedimiento se convierte en un reto para el anestesiólogo por compartir el campo quirúrgico con el cirujano. Gracias al entrenamiento previo en cadáveres y en modelos experimentales animales y al trabajo multidisciplinario llevado a cabo, es que se llega a mostrar buenos resultados.

Heterotopic transplantation of glycerin-preserved trachea: effect of respiratory epithelium desquamation on acute rejection

An effective preservation method and decreased rejection are essential for tracheal transplantation in the reconstruction of large airway defects. Our objective in the present study was to evaluate the antigenic properties of glycerin-preserved tracheal segments. Sixty-one tracheal segments (2.4 to 3.1 cm) were divided into three groups: autograft (N = 21), fresh allograft (N = 18) and glycerin-preserved allograft (N = 22). Two segments from different groups were implanted into the greater omentum of dogs (N = 31). After 28 days, the segments were harvested and analyzed for mononuclear infiltration score and for the presence of respiratory epithelium. The fresh allograft group presented the highest score for mononuclear infiltration (1.78 ± 0.43, P <= 0.001) when compared to the autograft and glycerin-preserved allograft groups. In contrast to the regenerated epithelium observed in autograft segments, all fresh allografts and glycerin-preserved allografts had desquamation of the respiratory mucosa. The low antigenicity observed in glycerin segments was probably the result of denudation of the respiratory epithelium and perhaps due to the decrease of major histocompatibility complex class II antigens.

Trasplante de laringe y traquea superior como opción terapeutica en trauma laringotraqueal irreparable / Larinx and tracheal trasplantation for laringeal trauma

El trasplante de órganos no vitales se está abriendo espacio como una opción terapéutica con el propósito de mejorar la calidad de vida del ser humano. Cada vez aumenta más el interés en la comunidad científica debido a los avances en las técnicas microquirúrgicas y en las terapias inmunosuporesoras. En el caso de la laringe, el trasplante de ella se vislumbra como una opción real en aquellos casos en que, por traumas severos, quemaduras o tumores benignos gigantes, se han perdido todas sus funciones sin otra posibilidad de reconstrucción. Las técnicas actuales de revascularización y los avances en la inmunosupresión, permiten realizar esta cirugía dentro de un marco razonable de seguridad para el paciente. El aspecto menos favorable hasta ahora tiene que ver con la reinervación, pero el mejor entendimiento de ella se logrará en la medida que se realicen más trasplantes. No es utópico entonces pensar en la posibilidad de trasplantar en un futuro no lejano pacientes sometidos a laringectomía por ciertos subgrupos de tumores T3 de laringe

Viability of cells in cryopreserved canine cardiovascular organs for transplantation

To determine applicability of the cryopreservation procedure for vessel grafts, the viability of endothelial cells (ECs) among the whole cells in three kinds of organs artery, vein, trachea in mongrel dogs was evaluated on the basis of histological analysis. The Griffonia simplicifolia agglutins-fluorescein isothiocyanate (GSA-FITC) and propidium iodide (PI) double staining methods were combined with flow cytometry (FCM), which was able to simultaneously determine the viability of whole cells and ECs from the same tissue, were performed after harvesting, after antibiotic solution treatment, and after cryopreservation and thawing. In most cases, the viability of ECs is lower than that of whole cells from veins and arteries. The viability of whole cells in veins was maintained until the antibiotic solution treatment and then decreased significantly after cryopreservation and thawing, while the ECs began to decrease significantly after the antibiotic solution treatment and more markedly decreased after thawing. The viability of ECs and whole cells from arteries was similar to that of the veins' conditions. The viability of whole cells from the trachea decreased with a similar pattern to that of the ECs from vessels. In consideration of maintaining cell viability among the three kinds of organs, the viability of arteries was better than that of the others. The cells in the trachea demonstrated a lower viability than the vessels. The effect of antibiotic solution treatment on the reduction of cell viability depends on the treatment time and temperature.

The role of omentopexy in tracheal transplantation in dogs

The major step toward successful tracheal transplantation is revascularization of the grafted trachea. There are many reports that although omentopexy is an effective method to facilitate neo-vascularization in tracheal transplantations, the procedure has not been accepted universally in the transplantation field. It remains unclear whether an omentopexy can successfully revascularize tracheal graft regardless of the length of graft. This study was undertaken to assess the usefulness of omentopexy for long-segment(more than 4 cm) tracheal allotransplantation. We have performed six tracheal transplantations with omentopexy (group A) and four tracheal transplantations without omentopexy (group B) in mongrel dogs from July 1993 to February 1995. Five mid-portion tracheal rings were removed from ten donor dogs and ten corresponding tracheal rings were removed from the ten recipient dogs. The excised tracheal rings from the donors were transplanted to the recipient tracheal-excised sites. All the recipients were given cyclosporine, azathioprine, and prednisolone for immunosuppression in the post-operative period. The histologic results of all the surviving members of group B were better than those of the group A. These findings indicate that omentopexy has a limitation, it is not a major method for graft revascularization. Therefore the length of the tracheal graft was greater than 4.0 cm, for its viability, a longer tracheal graft requires some other blood supply aside from the omentopexy.

Criopreservación de traquea: estudio experimental / Cryopreservation of trachea: experimental study

El propósito de este estudio fue de evaluar la viabilidad de segmentos de tráquea implantados en el omento mayor después de haber sido sometidos o no a criopreservación. Se utilizaron dos grupos de cinco perros adultos mestizos. En el grupo I los segmentos traqueales fueron sometidos a criopreservación en nitrógeno líquido a -90oC por 15 días, tras los cuales se implantó en el omento mayor de los perros receptores. En el grupo II, los segmentos fueron implantados en el omento inmediatamente después de haber sido obtenidos de los perros donadores. Todos los segmentos fueron estudiados 15 días después de su implantación. Los cambios histológicos fueron evaluados al azar en microscopía de luz, recibiendo una gradación numérica para cada uno de los cambios observados. Macroscópicamente todos los segmentos recuperados presentaron aspecto normal. Histológicamente al evaluar el cartílago, se encontró que el grupo II hubo gradación significativamente mayor; mientras que los cartílagos tratados con criopreservación no mostraron alteración alguna (p=0.018)fuera de esto no se encontró ninguna otra diferencia. Al perfundirlos con solución de tinta china a través de la arteria gastroepiploica derecha, se observó marcro y microscópicamente que todos los segmentos traqueales lograron ser revascularizados adecuadamente. Concluimos que la criopreservación de un segmento traqueal por 15 días en nitrógeno líquido, no altera la integridad histológica del mismo. Además el implante de un segmento traqueal en el omento mayor permite mantener su viabilidad gracias a la revascularización que se produce a partir del mismo omento

Transplante de traquéia: estudo experimental em cobaias / Trachea transplantation: experimental study in guinea-pigs

Objetivou-se obter um modelo experimental de reconstruçäo traqueal na cobaia. A técnica empregada foi a de transplante homógeno e autógeno de traquéia e os animais foram divididos em dois grupos, denominados aloenxerto (46 animais) e auto-enxerto (13 animais). Os animais de ambos os grupos foram sacrificados com 3, 7, 14, 30, 60, e 120 dias e estudada a histopatologia das traquéias transplantadas e dos receptores. As principais observaçöes foram de que a permeabilidade das vias aéreas era normal, apesar da ocorrência de estenose traqueal nos animais do grupo aloenxerto. Ocorreu reepitelizaçäo do aloenxerto e após um mês este foi recoberto por epitélio respiratório típico. Em relaçäo ao grupo aloenxerto, pode-se dizer que näo houve "rejeiçäo" ao tecido transplantado, que era fixado em soluçäo de formalina a 0,5% em pH-5,6, comportando-se como material imunologicamente inativo