Microbiological analysis of cryopreserved human heart valves after storage: a survey of 3 banks in Spain.

Several reports have shown liquid nitrogen containers as not being sterile. Microorganism transmission has been observed in different cells and tissues stored under this condition, but there is no data on contamination of stored human valves. We performed a survey on heart valve banking in Spain. Regarding the questionnaire, we have a complete microbiological analysis of 304 thawed tissues prior to implant. In six cases positive culture results were observed. Patient follow-up did not reveal any adverse effects. Although some other possibilities should be stated, contamination of heart valves during storage in liquid nitrogen should be considered as a risk element in tissue banking. Strategies to asses and prevent microbial transmission from liquid nitrogen to heart valve banking ought to be further developed.

Técnica de cultivo de mioblastos autólogos humanos para transplante clínico / Technique of culture of human autologous mioblasts for clinic transplant

Introducción: El trasplante celular para reparar o regenerar el miocardio dañado es un nuevo objetivo en la enfermedad cardiovascular. Los mioblastos esqueléticos autólogos son las células más estudiadas y constituyen la primera elección para la reparación cardíaca. Objetivos: Puesta a punto de la técnica de cardiomioplastia celular en muestras obtenidas de donantes multiorgánicos y llevar a cabo esta técnica junto con la revascularización en dos pacientes. Material y métodos: Se han obtenido 15 biopsias de músculo vasto lateral de donantes multiorgánicos y de dos pacientes con infarto de miocardio no reciente. Después de tres semanas de cultivo, se evaluó en todas las muestras el porcentaje de mioblastos con los anticuerpos CD56, desmin y miogenin. Los dos pacientes fueron sometidos a cirugía de revascularización e inyección intramiocárdica de mioblastos esqueléticos autólogos obtenidos tras cultivo con suero autólogo. Resultados: Se demostró la presencia de un gran número de células positivas con los marcadores desmina y miogenin. El implante de mioblastos esqueléticos autólogos no se asoció con el desarrollo de efectos adversos. Conclusiones: En pacientes con un infarto de miocardio no reciente, el tratamiento con mioblastos en conjunción con bypass arteria coronaria es seguro y fácil y es relativamente fácil obtener mioblastos de tejido muscular para trasplantar (AU)

Introduction: Cellular transplant to repair or regenerate damaged myocardium is a new objective in cardiovascular disease. The autologous skeletal myoblasts are the most studied cells and constitute the first election for cardiac repair. Objectives: fine adjustment of the cellular cardiomyoplasty technique with revascularization in two patients. Material and methods: 15 biopsies were obtained from multiorganic donors and from two patients with no recent infarct. After three weeks of culture, the percentage of myoblasts were evaluated using monoclonal antibodies CD56, desmin and myogenin. The two patients were subjected to revascularization surgery and intramyocardic injection of autologous skeletic myoblasts obtained after culture with autologous serum. Results: The presence of a great number of positive cells with desmin and myogenin markers was shown. The implantation of autologous skeletal myoblasts was not associated with the development of adverse effects. Conclusions: In patients without a recent myocardium infarct, the treatment with myoblasts together with coronary artery bypass is sure and easy and it is straightforward to obtain myoblasts from muscle tissue for transplant (AU)

Function of cryopreserved pig aortas.

OBJECTIVES: This paper analyzes the influence of storage in the gas phase or liquid phase on grafts, together with the thawing method (15 degrees C/min or 100 degrees C/min) on the postthawing activity of pig cryopreserved arterial grafts (aortas). MATERIALS AND METHODS: Obtainment of arterial grafts (aortas) was from pigs with an ischemic time not greater than 2 h. Each aorta was divided into five fragments and assigned randomly to one control group of fresh aorta and four groups of cryopreserved aortas: group 1: gas phase/slow thawing; group 2: gas phase/rapid thawing; group 3: liquid phase/slow thawing; and group 4: liquid phase/rapid thawing. After the incubation in antibiotic solution, the cryopreservation in RPMI medium +10% DMSO was carried out and the level of cooling used was a reduction of 1 degrees C/min. The contraction and relaxation responses of the fresh and frozen/thawed arteries were carried out in organ baths. RESULTS: After thawing, the sensitivity to various agonists and maximal responses to the endothelium-dependent and independent relaxant agents were decreased. The maximal responses to the tested vasoconstrictors (KCl and noradrenaline) were, respectively, 13% and 24% of the responses obtained in unfrozen aortas. The endothelium-independent relaxant responses to sodium nitroprusside (SNP) were reduced and important reductions of the endothelium-dependent relaxant responses to acetylcholine were produced. CONCLUSIONS: The cryopreservation of pig aortas under the conditions used in this study led to a decrease in the contractility of the pig aortas, as well as a decrease in the endothelium-independent relaxant responses. On the other hand, no apparent preservation of the endothelium-dependent relaxant responses was observed.

Effects of cryopreservation and thawing on the structure of vascular segment.

The objective of this study was to analyze the importance of the quality of the vascular segment to be cryopreserved and the influence of storage in a gas phase, a liquid phase, or after accidental immersion in liquid nitrogen. In addition, we investigated the effects of rapid versus slow thawing on the occurrence of fractures and changes in the structure of the vessel wall. The tissue sources were whole thoracic and abdominal aortas from 15 pigs. Each aorta was cut into equal segments and randomly assigned to each study group. One segment of fresh unfrozen aorta of the same size was used as a control. The samples were cryopreserved using a programmed apparatus. After 2 weeks the arterial segments were thawed rapidly or slowly. A great variation in the results was obtained depending on the quality of the control. Although endothelial cells were better preserved in the liquid phase, the internal elastic lamina and elastic lamelli showed better preservation and fewer microfractures in the gas phase. The internal elastic lamina showed a greater number of microfractures when an accidental immersion in liquid nitrogen had taken place. Furthermore, better preservation of the structure of the vascular segment was observed with a slow thawing method. In general, the conditions of storage and the method of thawing seem to damage the structure of vascular segments. It is necessary to use a severe protocol of donor and vascular segment selection to optimize the post-thaw quality of the cryopreserved samples.