Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects

Abstract Oral mucosa has been highlighted as a suitable source of epidermal cells due to its intrinsic characteristics such as its higher proliferation rate and its obtainability. Diabetic ulcers have a worldwide prevalence that is variable (1%-11%), meanwhile treatment of this has been proven ineffective. Tissue-engineered skin plays an important role in wound care focusing on strategies such autologous dermal-epidermal substitutes. Objective The aim of this study was to obtain autologous dermal-epidermal skin substitutes from oral mucosa from diabetic subjects as a first step towards a possible clinical application for cases of diabetic foot. Material and Methods Oral mucosa was obtained from diabetic and healthy subjects (n=20 per group). Epidermal cells were isolated and cultured using autologous fibrin to develop dermal-epidermal in vitro substitutes by the air-liquid technique with autologous human serum as a supplement media. Substitutes were immunocharacterized with collagen IV and cytokeratin 5-14 as specific markers. A Student´s t- test was performed to assess the differences between both groups. Results It was possible to isolate epidermal cells from the oral mucosa of diabetic and healthy subjects and develop autologous dermal-epidermal skin substitutes using autologous serum as a supplement. Differences in the expression of specific markers were observed and the cytokeratin 5-14 expression was lower in the diabetic substitutes, and the collagen IV expression was higher in the diabetic substitutes when compared with the healthy group, showing a significant difference. Conclusion Cells from oral mucosa could be an alternative and less invasive source for skin substitutes and wound healing. A difference in collagen production of diabetic cells suggests diabetic substitutes could improve diabetic wound healing. More research is needed to determine the crosstalk between components of these skin substitutes and damaged tissues.

Cytotherapy for Osteonecrosis of Hip.

Osteonecrosis of hip is a pathological condition that leads to collapse of the femoral head, & the need for total hip replacement (THR). Research has shown that at the cellular level there is decrease in osteoblastic activity & the local mesenchymal stem cells (MSC) population that leads to osteonecrosis of femoral head (ONFH). Cellular therapy could thus be used to improve the local cellular environment. Th is can be achieved by implanting bone marrow, containing osteogenic precursors into the necrotic lesion of the femoral head.

In vitro proliferation and differentiation of hepatic oval cells and their potential capacity for intrahepatic transplantation

Hepatic oval cells (HOCs) are recognized as facultative liver progenitor cells that play a role in liver regeneration after acute liver injury. Here, we investigated the in vitro proliferation and differentiation characteristics of HOCs in order to explore their potential capacity for intrahepatic transplantation. Clusters or scattered HOCs were detected in the portal area and interlobular bile duct in the liver of rats subjected to the modified 2-acetylaminofluorene and partial hepatectomy method. Isolated HOCs were positive for c-kit and CD90 staining (99.8% and 88.8%, respectively), and negative for CD34 staining (3.6%) as shown by immunostaining and flow cytometric analysis. In addition, HOCs could be differentiated into hepatocytes and bile duct epithelial cells after leukemia inhibitory factor deprivation. A two-cuff technique was used for orthotopic liver transplantation, and HOCs were subsequently transplanted into recipients. Biochemical indicators of liver function were assessed 4 weeks after transplantation. HOC transplantation significantly prolonged the median survival time and improved the liver function of rats receiving HOCs compared to controls (P=0.003, Student t-test). Administration of HOCs to rats also receiving liver transplantation significantly reduced acute allograft rejection compared to control liver transplant rats 3 weeks following transplantation (rejection activity index score: control=6.3±0.9; HOC=3.5±1.5; P=0.005). These results indicate that HOCs may be useful in therapeutic liver regeneration after orthotopic liver transplantation.

Establishment of an Allo-Transplantable Hamster Cholangiocarcinoma Cell Line and Its Application for In Vivo Screening of Anti-Cancer Drugs

Opisthorchis viverrini (O. viverrini) is a well-known causative agent of cholangiocarcinoma (CCA) in humans. CCA is very resistant to chemotherapy and is frequently fatal. To understand the pathogenesis of CCA in humans, a rodent model was developed. However, the development of CCA in rodents is time-consuming and the xenograft-transplantation model of human CCA in immunodeficient mice is costly. Therefore, the establishment of an in vivo screening model for O. viverrini-associated CCA treatment was of interest. We developed a hamster CCA cell line, Ham-1, derived from the CCA tissue of O. viverrini-infected and N-nitrosodimethylamine-treated Syrian golden hamsters. Ham-1 has been maintained in Dulbecco's Modified Essential Medium supplemented with 10% fetal bovine serum for more than 30 subcultures. These cells are mostly diploid (2n=44) with some being polyploid. Tumorigenic properties of Ham-1 were demonstrated by allograft transplantation in hamsters. The transplanted tissues were highly proliferative and exhibited a glandular-like structure retaining a bile duct marker, cytokeratin 19. The usefulness of this for in vivo model was demonstrated by berberine treatment, a traditional medicine that is active against various cancers. Growth inhibitory effects of berberine, mainly by an induction of G1 cell cycle arrest, were observed in vitro and in vivo. In summary, we developed the allo-transplantable hamster CCA cell line, which can be used for chemotherapeutic drug testing in vitro and in vivo.

Impacto de la terapia celular en el síndrome del túnel carpiano / Impact of cell therapy in carpal tunnel syndrome

Se expone una pequeña serie de pacientes con síndrome del túnel del carpo a quienes se les realizó implante de células mononucleares autólogas de sangre periférica para evaluar la factibilidad y seguridad de estas al sexto mes de realizado el proceder. Se incluyeron 6 pacientes atendidos en el Servicio de Ortopedia del Hospital General Docente Enrique Cabrera . La mejoría de los síntomas comenzó a la semana de realizado el proceder. El dolor y el calambre fueron los primeros en desaparecer; la mejoría aumentó al mes y se mantuvo hasta el sexto mes de evaluados. Las manifestaciones clínico-neurológicas mejoraron en el 80,3 por ciento de los pacientes con mejoría, además, en el estudio de conducción motora y sensitiva. No hubo reacción al implante. La mejoría de las manifestaciones clínicas y de los estudios de conducción apoyan la mediación de las células madre en la acción antiinflamatoria, la revascularización y la remielinización del nervio mediano, lo que se expresa en las respuestas favorables obtenidas

We present a small series of patients with carpal tunnel syndrome who underwent implantation of autologous mononuclear cells from peripheral blood to assess the feasibility and safety of these in the sixth month after that procedure. We included 6 patients treated at the Department of Orthopedic in The Enrique Cabrera General Teaching Hospital. The improvement in symptoms began one week after the procedure. Pain and cramping were the first to disappear, the improvement increased one month after and it was maintained until the sixth month of evaluation. The clinical-neurological manifestations improved in 80.3 percent of patients, as well as in the study of motor and sensory conduction. There was no reaction to the implant. The improvement of the clinical manifestations and conduction studies support the mediation of stem cells in inflammatory action, revascularization and remyelination of the median nerve, which is expressed in the positive responses obtained

Terapia celular en fractura del fémur / Cell therapy in femur fractures

La medicina regenerativa ha abierto una posibilidad más para la consolidación efectiva y la recuperación rápida de los pacientes con lesiones traumáticas. Se presenta un paciente masculino, blanco, de 46 años de edad con antecedentes de accidente de tránsito. Se diagnosticó fractura del tercio medio del fémur izquierdo y las radiografías simples evidenciaron conminución Grado IV. Egresó después de 20 días de internamiento con persistencia del dolor a pesar de habérsele administrado analgésicos cada 4-6 horas. Se indicó terapia celular que se realizó en régimen ambulatorio. A partir de las primeras 48 horas la mejoría se incrementó progresivamente, logró estabilidad y desapareció el dolor en el foco de fractura, síntoma que mantenía desde el accidente. A las 8 semanas después de la terapia celular se observó mejoría radiológica. En general, su evolución se consideró satisfactoria por la pronta mejoría y su incorporación a la vida social. Este es el primer paciente en la provincia de Artemisa en que se ha realizado este nuevo tipo de terapia y hasta donde conocemos en el momento de la redacción de este trabajo, también el primero informado en la literatura científica en Cuba

Regenerative medicine has opened another opportunity for effective consolidation and rapid recovery of patients with traumatic injuries. We present a 46 year- old white male patient with a history of traffic accident. A middle third left femur fracture was diagnosed and plain radiographs showed IV grade comminution. He was released after 20 days of hospitalization with persistent pain despite of pain medication every 4-6 hours. Cell therapy was prescribed and it was performed on outpatient basis. After 48 hours the improvement was increased progressively, stability was achieved and pain disappeared in the fracture site, this was a symptom present since the accident. 8 weeks after cell therapy, radiological improvement was observed. In general, his eveolution was considered satisfactory for the fast recovery and its incorporation into social life. This is the first patient in Artemisa province who underwent this new type of therapy and as far as we know at the time of this writing, it is also the first reported in the scientific literature in Cuba

Comparação entre membrana amniótica com e sem epitélio como substrato para cultura de células epiteliais do limbo ex vivo / Comparison between amniotic membrane with and without epithelium as a support for human limbal epithelial cells cultured ex vivo

OBJETIVO: Avaliar a eficácia e aspecto estrutural de células límbicas epiteliais humanas cultivadas sobre membrana amniótica (MA) com e sem epitélio. MÉTODOS: As culturas límbicas foram obtidas a partir de rima corneoescleral remanescentes de transplantes de córnea de 6 diferentes doadores. Cada explante foi cultivado em três diferentes grupos: MA desepitelizada por tripsina (Grupo 1), MA com epitélio íntegro (Grupo 2) e controle (Grupo 3). A migração epitelial foi avaliada por microscopia de contraste de fase. Após 15 dias, as células cultivadas sobre MA foram submetidas à microscopia eletrônica para avaliar migração e adesão epitelial. RESULTADOS: Todas as células do grupo controle cresceram até atingir confluência. Somente uma das culturas em membrana amniótica desepitelizada não apresentou crescimento epitelial. O crescimento de células epiteliais sobre membrana amniótica epitelizada foi observada em apenas uma cultura. CONCLUSÃO: Baseando-se nestes achados, o uso de membrana amniótica desepitelizada aparenta ser o melhor substrato para migração e adesão epitelial comparando com membrana amniótica epitelizada. Remover o epitélio da membrana amniótica demonstra ser um importante passo para estabelecer culturas de células sobre membrana amniótica.

PURPOSE: To evaluate the efficacy and ultrastructural aspects of human limbal epithelial cells cultured on amniotic membrane (AM) with and without epithelium. METHODS: Limbal epithelial cell cultures were established from cadaveric cor neo-scleral rim explants derived from 6 different donors. The explants from each donor were placed under 3 different groups: on human preserved AM with epithelium (Group 1), AM deepithelialized with trypsin (Group 2) and control (Group 3). The epithelial cell migration was evaluated under phase contrast microscopy. After 15 days, the amniotic membrane with cells cultures were removed and submitted to scanning and transmission electron microscopy to check for epithelial migration and adhesion. RESULTS: All epithelial cell cultures from the controls grew over the botton of the culture plate wells until reaching confluence. Epithelial cultures grew over all but one denuded amniotic membrane. In the group amniotic membrane with epithelium, epithelial cell growing was observed only in 1 well. CONCLUSIONS: Using this model, denuded amniotic membrane appeared to be the best substrate for epithelial cell migration and adhesion comparing to amniotic membrane with epithelium. Removal of amniotic membrane epithelial seems to be an important step for establishing limbal epithelial cell culture on amniotic membrane.

Microencapsulación de células y tejido para terapia celular / Cellular and tissue microencapsulation for cellular therapy

Microencapsulation is a technique that protects viable cells in semi-permeable membranes, which allow passage of essential molecules while stopping larger molecules, such as antibodies, involved in the death of transplanted cells. This allows the avoidance of immunosuppressive drugs. Several substances have been used for this purpose, and alginate is one of the most studied and validated. Alginate is extracted from algae present in African and Chilean coasts; different algae can be mixed in variable proportions to produce alginate with distinct characteristics. Commercial alginate evokes an inflammatory response that results in the death of transplanted cells. High purity alginate has already been developed to avoid this issue. There are several applications to this technique, as there are a large number of pathologies that result from the destruction or extraction of tissues, with the consequent loss of function (diabetes mellitus or post-surgical hypoparathyroidism, for example). Finally, there is an additional interest in alginate microencapsulation in this country, given that it can be easily obtained from national algae.

La microencapsulación es una técnica que protege células viables en membranas semi-permeables, que permite el paso de moléculas que son esenciales para la célula y a la vez impide el paso de otras, como los anticuerpos, involucradas en la destrucción celular. Esto permite evitar el uso de drogas inmunosupresoras. Variadas biomacromoléculas pueden ser utilizadas con este fin, siendo el alginato uno de los biopolímeros más validados y estudiados. El alginato es un polisacárido amónico formado por unidades acidas b-L-manurónicas y a-L-gulorónicas, extraído desde algas presentes en costas africanas y chilenas. Así, diferentes algas pueden ser mezcladas en proporciones variables para producir alginatos de distintas características. El alginato comercial produce una respuesta inflamatoria que causa la muerte de las células trasplantadas; ya se han desarrollado alginatos de alta pureza para evitar este problema. Existen varias aplicaciones para esta técnica, ya que existen diversas patologías caracterizadas por una pérdida de función por destrucción o extracción de tejido (por ejemplo, diabetes mellitus o hipoparatiroidismo post-quirúrgico). Esta técnica representa un especial interés en Chile, ya que el alginato puede ser obtenido fácilmente a partir de algas chilenas.

Técnica de separação da membrana de Descemet para transplante de células endoteliais da córnea: estudo experimental em coelhos / Technique for separating Descemet membrane for corneal endothelial cells transplantation: experimental study in rabbits

OBJETIVO: Avaliar a porcentagem de dano endotelial induzido por uma técnica cirúrgica para a separação da membrana de Descemet contendo endotélio sadio, analisar a viabilidade e eficácia desta técnica, e avaliar a porcentagem de dano endotelial causado pela inversão da córnea em câmara anterior artificial. MÉTODOS: As córneas de três grupos de 12 coelhos da linhagem Nova Zelândia foram avaliadas. O grupo 1 foi usado como controle; portanto, as córneas foram analisadas após coletadas e trepanadas. O grupo 2 foi analisado após a inversão da córnea (endotélio para cima na posição convexa), montada em câmara anterior artificial, para o cálculo da porcentagem do dano endotelial induzido por esta inversão. O grupo 3 foi avaliado após a separação entre a membrana de Descemet e o estroma com o uso de substância viscoelástica em córneas invertidas e montadas em câmara anterior artificial. O dano endotelial foi avaliado por meio de fotografias digitais tiradas no microscópio após impregnar o endotélio com vermelho de alizarina. Amostras do grupo 3 foram processadas para avaliação histopatológica. RESULTADOS: O grupo 3 (separação viscoelástica) apresentou um índice de lesão celular endotelial de 10,06 por cento, o grupo 2 apresentou um índice de 3,58 por cento e o grupo controle um índice de 0,18 por cento de lesão celular endotelial (p<0,05). A avaliação histológica das córneas do grupo 3 revelou que aproximadamente 120 µm de espessura estromal manteve-se aderido à membrana de Descemet. CONCLUSÃO: Esta técnica deve ser melhor investigada, pois é uma alternativa viável e eficaz de separação da membrana de Descemet para transplante celular endotelial, já que o porcentual de dano celular induzido é de 10,06 por cento. A porcentagem de dano celular causado pela inversão da córnea em câmara anterior artificial foi de 3,58 por cento.

PURPOSE: To evaluate the percentage of endothelial cell damage induced during a surgical technique of Descemet's membrane separation containing healthy endothelium, analyze the viability and efficacy of this technique, and evaluate the percentage of endothelial cell damage caused by inversion of the cornea on an artificial anterior chamber. METHODS: The corneas from three groups of 12 New Zealand rabbits were evaluated. The Group one was used as the control, so the corneas were analyzed after collected and trephinated. The Group two was analyzed after inversion of the cornea (endothelial side up at a convex shape) mounted on an artificial anterior chamber to calculate the percentage of endothelial cell damage caused by this inversion. The Group three was evaluated after the separation between the Descemet's membrane and the stroma using viscoelastic substance in corneas inverted and mounted on an artificial anterior chamber. The endothelial cell damage was analyzed by digital photographs taken under a microscope after staining the endothelium with alizarin red. Group three samples were processed for histologic evaluation. RESULTS: The Group three (viscoelastic separation) showed an index of endothelial cell damage of 10.06 percent, the Group two showed an index of 3.58 percent and the control group an index of 0.18 percent of endothelial cell damage (p<0.05). Histological evaluation of the Group three corneas revealed that approximately a 120 µm thickness of stroma remained attached to the Descemet's membrane. CONCLUSION: This technique should be better investigated because it is a viable and efficient alternative of Descemet's membrane separation for endothelial cells transplantation, since the percentage of induced cell damage is 10.06 percent. The percentage of endothelial cell damage caused by inversion of the cornea on an artificial anterior chamber was 3.58 percent.

Terapia celular no tratamento da insuficiência cardíaca isquêmica / Cellular therapy in the treatment of ischemic heart failure

Neste artigo, os autores discutem o estado da arte da terapia celular no tratamento da insuficiencia cardiaca isquêmica. São apresentados os principais tipos celulares e suas particularidades no tratamento dessa doença.

In this article the authors discuss the state of the art on cell therapy for ischemic heart failure. The principal cell types and their specific characteristics for the treatment of this pathology are presented.

Establecimiento de la primera línea celular de paratoroides humana / Establishment of first cell line of human parathyroid

Para el manejo de pacientes con hipoparatiroidismo postquirúrgico se ha intentado el transplante de células de paratiroides humanas. Los problemas para este eventual tratamiento han sido mantener cultivos duraderos a largo plazo y mantener cultivos con función endrocina normal. Existe un método de inmortalización celular, descrito por Caviedes y cols. que permite mantener células humanas con la capacidad de proliferar sin perder sus funciones de células diferenciadas. Con este método de inmortalización se logrará establecer una línea celular continua de paratiroides humana con función endrocina normal a largo plazo: esta última definida como la capacidad de respuesta secretoria normal de paratohormona (PTH), frente a distintas concentraciones de calcio extracelular. En este artículo se presenta el procedimiento y sus resultados in vitro.

For the handling of patients with postsurgical hypoparathyroidism, the trasplant of cells of human parathyroid has been tried. The difficulties to establish this type of cultures have been to maintain cultures lasting in the term and to maintain cultures with normal endocrin function. A method of cellular inmortalization, described by Caviedes et al. exists that allow to maintain human parathyroid cells with the capacity to proliferate without losing their differentiated functions. With this method of inmortalization it will be managed in the long term to establish a continuous parathyroid cellular line with normal endocrinal function, defined as the capacity of normal secretion of paratohormona (PTH), as opposed to different extracellular calcium concentrations. We present de procedure and its in vitro results.

Cardioimplante celular para reparar tejido cardíaco: ¿un nuevo concepto terapéutico? / Cell cardiac-implant for cardiac issue repair. A new therapeutic concept

El concepto clásico de que el corazón es un órgano no regenerativo ha cambiado en los últimos años: hoy día se considera que el corazón es un órgano en regeneración continua. Los mecanismos que posee el organismo para la renovación de los tejidos son limitados y dependen de la rapidez de instauración del daño. El cardioimplante celular consiste en injertar células diferenciadas o progenitoras en el miocardio lesionado, con el fin de inducir el crecimiento de nuevas fibras musculares y el desarrollo de angiogénesis, para mejorar y contribuir a la contracción sincrónica. Se han utilizado diferentes poblaciones celulares para tal fin, injertadas directamente en el miocardio o inyecatadas en la circulación. En experimentación animal, en modelos de infarto de miocardio el implante de células autólogas diferenciadas (cardiomiocitos embrionarios, fetales, mioblastos esqueléticos) ha mostrado un mejoramiento en la función ventricular. Por otra parte, la utilización de células madre de médula ósea o tejidos extramedulares ha producido la regeneración de cardiomiocitos y estructuras vasculares incluyendo células endoteliales y musculares lisas. El 15 de junio de 2000 se inició en Francia la fase I clínica en diez pacientes con cardiopatía isquémica necrótica , disfunción ventricular izquierda severa. Los pacientes fueron tratados con implante epicárdico de mioblastos esqueléticos en las zonas no viables y revascularización en zonas isquémicas remotas al implante. El 60 por ciento de las zonas no viables donde se transplantaron los mioblastos adquirieron un aumento del espesor sistólico y contractilidad en las zonas necróticas. En el mundo ya han sido tratados cientos de pacientes, con diferentes poblaciones celulares, la mayoría con insuficiencia cardíaca secundaria a cardiopatía isquémica-necrótica, en los cuales se han obtenido resultados alentadores. Las evidencias actuales sugieren que en un futuro cercano el cardioimplante celular podría ser una opción válida par...

Ectopic development of skeletal muscle induced by subcutaneous transplant of rat satellite cells

The present study analyzes the ectopic development of the rat skeletal muscle originated from transplanted satellite cells. Satellite cells (10(6) cells) obtained from hindlimb muscles of newborn female 2BAW Wistar rats were injected subcutaneously into the dorsal area of adult male rats. After 3, 7, and 14 days, the transplanted tissues (N = 4-5) were processed for histochemical analysis of peripheral nerves, inactive X-chromosome and acetylcholinesterase. Nicotinic acetylcholine receptors (nAChRs) were also labeled with tetramethylrhodamine-labeled alpha-bungarotoxin. The development of ectopic muscles was successful in 86 percent of the implantation sites. By day 3, the transplanted cells were organized as multinucleated fibers containing multiple clusters of nAChRs (N = 2-4), resembling those from non-innervated cultured skeletal muscle fibers. After 7 days, the transplanted cells appeared as a highly vascularized tissue formed by bundles of fibers containing peripheral nuclei. The presence of X chromatin body indicated that subcutaneously developed fibers originated from female donor satellite cells. Differently from the extensor digitorum longus muscle of adult male rat (87.9 ± 1.0 æm; N = 213), the diameter of ectopic fibers (59.1 æm; N = 213) did not obey a Gaussian distribution and had a higher coefficient of variation. After 7 and 14 days, the organization of the nAChR clusters was similar to that of clusters from adult innervated extensor digitorum longus muscle. These findings indicate the histocompatibility of rats from 2BAW colony and that satellite cells transplanted into the subcutaneous space of adult animals are able to develop and fuse to form differentiated skeletal muscle fibers.

Transplante de hepatocitos en ratas con cirrosis biliar secundaria / Transplanted hepatocites in biliary cirrhotic rats

Antecedentes: Nuevas líneas de investigación para suplir la falta de donantes hepáticos se encuentran en desarrollo. El transplante de hepatocitos se presenta como una alternativa terapéutica de futuro para el tratamiento de diversas afecciones crónicas del hígado en fase terminal. Objetivo: Evaluar viabilidad y cambios bioquímicos de hepatocitos transplantados en ratas cirróticas. Lugar de aplicación: Unidad de Medicina Experimental. Diseño: Experiemntal prospectivo controlado. Material: Ratas Wistar, sexo indistinto, 250 gramos (n=15). Hepatocitos: aislamiento con técnicas de colagenasa. Transplante: retroperitoneal. Histología: convencional, inmunohistoquímica. Método: Grupo donante (n=5), aislamiento de hepatocitos (viabilidad X = 65 por ciento, cantidad = 1x10). Grupo receptor (n=5)...

Effect of portal venous injection of donor spleen cells on skin allograft survival in rat.

BACKGROUND & OBJECTIVES: Pretransplantation injection of donor lymphohaemopoetic cells via portal venous route has been shown to improve allograft survival in mice. In the present study, the effect of perioperative portal venous administration of donor splenocytes on skin graft survival was investigated in comparison with intravenous administration of spleen cells in Swiss albino rat skin transplant model. METHODS: Using a single-donor survival study, skin allograft recipients received either no treatment, a single transfusion of donor spleen cells via portal vein or a single transfusion of donor splenocytes into vena cava. Spleen cell transfusion consisted 25x10(6) viable cells in a volume of 1ml given just before skin grafting. Skin graft survival was assessed by macroscopic appearance. Rejection was defined as the first day on which the entire surface of the graft was necrotic. Histologically necrosis, increased connective tissue, vascularity and polymorphonuclear leucocyte (PNL) infiltration were evaluated under light microscopy. RESULTS: In this survival study of skin allografts, with the injection of viable spleen cells into portal vein concomitant to skin grafting, significant prolongation of mean allograft survival was induced (20.3 days), compared with untreated recipients (6.5 days, P<0.001). In the histopathologic evaluation, less PNL infiltration, necrosis, increased vascularity and connective tissue repair were observed in vena porta group with no statistical significance. INTERPRETATION & CONCLUSION: It may be possible to develop protocols to induce transplantation tolerance based on the historical concept of donor specific antigen administration. However, it appears that donor spleen cell transfusion alone is not sufficient to prevent graft rejection. Thus, more efficient combination treatments are required to induce a state of durable tolerance.

Cultivo primario e inmortalización de células de paratiroides para trasplante celular, en hipoparatiroidismo quirúrgico / Primary culture and immortalization of parathyroid cells for cell transplantation, in surgical hypoparathyroidism

El hipoparatiroidismo permanente ocurre después de tireidectomía (0,2-4 por ciento) o de cirugía paratiroidea. Lamentablemente el autotransplante no es 100 por ciento efectivo para prevención, y los pacientes deben recibir suplementación de vitamina D y calcio de por vida, con un costoso y a veces difícil manejo médico. Poca experiencia hay a nivel mundial de alotrasplantes paratiroideos en humanos. Un grupo de investigadores logró un período de sobrevida del injerto de 1 año en 8 pacientes, pero sin consignar los requerimientos de calcio y vitamina D. La dificultad de esta terapia es el rechazo por aloinmunización, y el establecimiento de cultivos primarios duraderos que permita conseguir una masa de células suficiente para el trasplante. Se ha logrado mantener cultivos, y función endocrina de ellos, por 60 días máximo. Nuestro objetivo es modificar y optimizar los cultivos primarios de paratiroides humana para: a)Obtener una línea continua de células paratiroideas, b)caracterizar la línea en cuanto a función endocrina, y c)disminuir la antigenicidad, como fuente futura de trasplante celular. La serie presentada incluye 5 pacientes intervenidas quirúrgicamente por hiperparatiroidismo primario, con diagnóstico definitivo de adenoma paratiroideo. Las muestras fueron sometidas a digestión enzimática y disgregación mecánica, cultivándose finalmente en placas de Petri a 37 °C. Resultados: Todos los cultivos primario fueron efectivos, con morfología típica a la microscopia. El primer cultivo creció y produjo PTH, pero no sobrevivió a contaminación del medio de cultivo. Los otros 4 están aún en período de expansión (crecimiento y multiplicación) con 150,60,40 y 35 días de cultivo. La función endocrina de las células en cultivo fue estudiada midiendo PTH en el medio de cultivo. Se obtuvo una producción promedio de 521,6 pg/ml en 24 horas (224-730 pg/ml). Todos los cultivos fueron positivos para esta medición.

Tissue engineering: prospect for regenerating periodontal tissues.

New advancements in technological fields, continually has had a major impact on dental practice. The emergence of tissue engineering and biomimetic concepts has enhanced the predictability of existing therapy and also has radically recast approaches towards the dentoalveolar reconstruction. Tissue engineering in the simplest sense is a combination of material sciences and biology to repair tissues and organs which will unquestionably offer an exciting therapeutic alternative that have never been available before. This article is a brief introduction to the ever expanding field of tissue engineering and its possible implication in periodontal regeneration.

Biology and clinical utilization of mesenchymal progenitor cells

Within the complex cellular arrangement found in the bone marrow stroma there exists a subset of nonhematopoietic cells referred to as mesenchymal progenitor cells (MPC). These cells can be expanded ex vivo and induced, either in vitro or in vivo, to terminally differentiate into at least seven types of cells: osteocytes, chondrocytes, adipocytes, tenocytes, myotubes, astrocytes and hematopoietic-supporting stroma. This broad multipotentiality, the feasibility to obtain MPC from bone marrow, cord and peripheral blood and their transplantability support the impact that the use of MPC will have in clinical settings. However, a number of fundamental questions about the cellular and molecular biology of MPC still need to be resolved before these cells can be used for safe and effective cell and gene therapies intended to replace, repair or enhance the physiological function of the mesenchymal and/or hematopoietic systems

Tissue restoration, tissue engineering and regenerative medicine

Recently, thanks to the rapid progress of new technologies in cell modulation, extracellular matrix fabrication and synthetic polymers mimicking bodily structures, the self-regeneration of bodily defects by host tissue has been considered by many researchers. The conventional science of art in biomaterials has been concerned with restoring damaged tissue using non-biological materials such as metals, ceramics and synthetic polymers. To overcome the limitations of using such non-viable materials, several attempts to construct artificial organs mimicking natural tissue by combining modulated cells with extracellular matrix-hybridized synthetic polymers have produced many worthy results with biologically functioning artificial tissues. The process involved in manufacturing biomaterials mimicking living tissue is generally called tissue engineering. However recently, the extension of knowledge about cell biology and embryology has naturally moved the focus from tissue restoration to tissue regeneration. Especially, embryonic and mesenchymal stem cells are attractive resources due to their potential for the differentiation of various tissue cells in response to signal transduction mediated by cytokines. Although no one knows yet what is the exact factor responsible for a stem cell's ability to differentiate between specific cells to generate specific tissue, what has been agreed is that delivering stem cells into the body provides a strong potential for the regeneration of tissue. In this review, the historical issues and future possibilities involved in medical tissue restoration and tissue regeneration are discussed.