Uso de la matriz extracelular como material para ingeniería de tejidos

Introducción: La evaluación de injertos vasculares de submucosa de intestino delgado para la regeneración de vasos sanguíneos ha producido una permeabilidad variable (0-100%) que ha sido concurrente con la variabilidad en las técnicas de fabricación. Metodología: Investigamos los efectos de fabricación en permeabilidad y regeneración en un diseño experimental de 22factorial que combino: 1) preservación (P) o remoción (R) de la capa estratum compactum del intestino, y 2) deshidratada (D) o hidratada (H), dentro de cuatro grupos de estudio (PD, RD, PH, RH). Los injertos fueron implantados en las Arterias Carótidas de porcinos (ID 4.5mm, N=4, 7d). Permeabilidad, trombogenicidad, reacción inflamatoria, vascularización, infiltración de fibroblastos, perfil de polarización de macrófagos y fuerza tensil biaxial fueron evaluadas. Resultados: Todos los injertos PD permanecieron permeables (4/4), pero tuvieron escasa vascularización e infiltración de fibroblastos. El grupo RD permaneció permeable (4/4), presentó una extensa vascularización e infiltración de fibroblastos, y el mayor número del fenotipo de macrófagos (M2) asociado a regeneración. El grupo RH presentó menor permeabilidad (3/4), una extensa vascularización e infiltración de fibroblastos, y un perfil dominante de M2. El grupo PH presentó el menor grado de permeabilidad, y a pesar de mayor infiltración celular que PD, exhibió un fenotipo de macrófagos dominante adverso. La elasticidad de los injertos R evolucionó de una manera similar a las Carótidas nativas (particularmente RD, mientras que los injertos P mantuvieron su rigidez inicial. Discusión: Concluimos que los parámetros de fabricación afectan drásticamente los resultados, siendo los injertos RD los que arrojaron mejores resultados.

Accesos vasculares para hemodiálisis, cuál es el más costo efectivo?

Marco conceptual: La enfermedad renal crónica es un serio problema de salud pública en nuestro país por la gran cantidad de recursos económicos que requiere su atención. La hemodiálisis es el tratamiento más usado en nuestro medio; el acceso vascular y sus complicaciones derivadas son el principal aspecto que incrementa los costos de atención en éstos pacientes. Materiales y métodos: Se realizó un estudio económico de los accesos vasculares en pacientes incidentes de hemodiálisis en el año 2012 en la agencia RTS-Fundación Cardio Infantil. Se estableció el costo de creación y mantenimiento del acceso con catéter central, fístula arteriovenosa nativa, fístula arteriovenosa con injerto; y el costo de atención de las complicaciones para cada acceso. Se determinó la probabilidad de ocurrencia de complicaciones. Mediante un árbol de decisiones se trazó el comportamiento de cada acceso en un período de 5 años. Se establecieron los años de vida ajustados por calidad (QALY) en cada acceso y el costo para cada uno de éstos QALY. Resultados: de 36 pacientes incidentes de hemodiálisis en 2012 el 100% inició con catéter central, 16 pacientes cambiaron a fístula arteriovenosa nativa, 1 a fístula arteriovenosa con injerto que posteriormente pasó a CAPD, 15 continuaron su acceso con catéter y 4 pacientes fallecieron. En 5 años se obtuvieron 2,36 QALY para los pacientes con catéter central que costarían $ 24.813.036,39/QALY y 2,535 QALY para los pacientes con fístula nativa que costarían $ 6.634.870,64/QALY. Conclusiones: el presente estudio muestra que el acceso vascular mediante fístula arteriovenosa nativa es el más costo-efectivo que mediante catéter

Pulsioximetría de pacientes en hemodiálisis, de la unidad de terapia renal – fundación cardioinfantil, análisis para establecer recomendaciones

Introducción. En Colombia, el 80% de los pacientes con enfermedad renal crónica en hemodiálisis tienen fístula arteriovenosa periférica (FAV) que asegura el flujo de sangre durante la hemodiálisis (1), la variabilidad en el flujo de sangre en el brazo de la FAV hacia la parte distal, puede afectar la lectura de la oximetría de pulso (SpO2) (2), llevando a la toma de decisiones equivocadas por el personal de salud. El objetivo de este estudio es aclarar si existe diferencia entre la SpO2 del brazo de la FAV y el brazo contralateral. Materiales y métodos. Se realizó un estudio de correlación entre los valores de SpO2 del brazo con FAV contra el brazo sin FAV, de 40 pacientes que asistieron a hemodiálisis. La recolección de los datos se llevó a cabo, con un formato que incluyó el resultado de la pulsioximetria y variables asociadas, antes, durante y después de la hemodiálisis. Se comparó la mediana de los deltas de las diferencias con pruebas estadísticas T Student – Mann Whitney, aceptando un valor significativo de p < 0,05. Resultados. No se encontraron diferencias estadísticamente significativas de la SpO2 entre el brazo con FAV y el brazo sin FAV, antes, durante y después de la diálisis, sin embargo si se apreció una correlación positiva estadísticamente significativa. Conclusiones. Se encontró correlación positiva estadísticamente significativa, donde no hubo diferencias en el resultado la pulsioximetría entre el brazo con FAV y brazo sin FAV, por lo tanto es válido tomar la pulsioximetría en cualquiera de los brazos.

Origin and Availability of Large Cavities for Barrow’s Goldeneye (Bucephala islandica), a Species at Risk Inhabiting the Eastern Canadian Boreal Forest

Large secondary-nesting birds such as ducks rely on appropriate cavities for breeding. The main objective of this study was to assess the availability of large cavities and the potential of a managed boreal coniferous landscape to provide nesting trees within the breeding area of the eastern population of Barrow’s Goldeneye (Bucephala islandica), a cavity-nesting species at risk in Canada. Woodpecker surveys were conducted in both conifer and mixed-wood landscapes, and cavities were sought in line transects distributed in unharvested and linear remnant stands of balsam fir (Abies balsamea) and black spruce (Picea mariana) as well as in cutblocks. No Pileated Woodpeckers (Dryocopus pileatus) were detected in the breeding area of Barrow’s Goldeneye, but the species was present in the nearby lowland area in which trembling aspen (Populus tremuloides) is abundant. Only 10 trees (0.2% of those sampled) supported cavities considered suitable for Barrow’s Goldeneye in terms of dimensions and canopy openness. Most of the suitable cavities found during this study were nonexcavated apical (chimney) cavities in relatively short snags that showed advanced states of decay. A diameter-at-breast-height threshold was determined for each tree species, after which the probability of cavity occurrence was enhanced in terms of potential cavity trees for Barrow’s Goldeneye. Remnant linear forest sites had lower potential tree densities than did their unharvested equivalents. Large cavities were thus a rare component in this boreal landscape, suggesting that they may be a limiting factor for this population at risk. Current even-aged forest management that mainly relies on clear-cut practices is likely to further reduce the potential of this landscape to provide trees with suitable cavities.

A system for studying epithelial-stromal interactions reveals distinct inductive abilities of stromal cells from benign prostatic hyperplasia and prostate cancer

The development of normal and abnormal glandular structures in the prostate is controlled at the endocrine and paracrine levels by reciprocal interactions between epithelium and stroma. To study these processes it is useful to have an efficient method of tissue acquisition for reproducible isolation of cells from defined histologies. Here we assessed the utility of a standardized system for acquisition and growth of prostatic cells from different regions of the prostate with different pathologies, and we compared the abilities of stromal cells from normal peripheral zone (PZ-S), benign prostatic hyperplasia (BPH-S), and cancer (CA-S) to induce the growth of a human prostatic epithelial cell line (BPH-1) in vivo. Using the tissue recombination method, we showed that grafting stromal cells (from any histology) alone, or BPH-1 epithelial cells alone produced no visible grafts. Recombining PZ-S with BPH-1 cells also produced no visible grafts (n = 15). Recombining BPH-S with BPH-1 cells generated small, well-organized and sharply demarcated grafts approximately 3-4 mm in diameter (n = 9), demonstrating a moderate inductive ability of BPH-S. Recombining CA-S with BPH-1 cells generated highly disorganized grafts that completely surrounded the host kidney and invaded into adjacent renal tissue, demonstrating induction of an aggressive phenotype. We conclude that acquisition of tissue from toluidine blue dye stained specimens is an efficient method to generate high quality epithelial and/or stromal cultures. Stromal cells derived by this method from areas of BPH and cancer induce epithelial cell growth in vivo which mimics the natural history of these diseases.

The long-term safety and efficacy of bilateral transplantation of human fetal striatal tissue in patients with mild to moderate Huntington's disease.

Huntington's disease (HD) is a fatal autosomal dominant neurodegenerative disease involving progressive motor, cognitive and behavioural decline, leading to death approximately 20 years after motor onset. The disease is characterised pathologically by an early and progressive striatal neuronal cell loss and atrophy, which has provided the rationale for first clinical trials of neural repair using fetal striatal cell transplantation. Between 2000 and 2003, the 'NEST-UK' consortium carried out bilateral striatal transplants of human fetal striatal tissue in five HD patients. This paper describes the long-term follow up over a 3-10-year postoperative period of the patients, grafted and non-grafted, recruited to this cohort using the 'Core assessment program for intracerebral transplantations-HD' assessment protocol. No significant differences were found over time between the patients, grafted and non-grafted, on any subscore of the Unified Huntington's Disease Rating Scale, nor on the Mini Mental State Examination. There was a trend towards a slowing of progression on some timed motor tasks in four of the five patients with transplants, but overall, the trial showed no significant benefit of striatal allografts in comparison with a reference cohort of patients without grafts. Importantly, no significant adverse or placebo effects were seen. Notably, the raclopride positron emission tomography (PET) signal in individuals with transplants, indicated that there was no obvious surviving striatal graft tissue. This study concludes that fetal striatal allografting in HD is safe. While no sustained functional benefit was seen, we conclude that this may relate to the small amount of tissue that was grafted in this safety study compared with other reports of more successful transplants in patients with HD.

In Vivo Comparison of Hard Tissue Regeneration with Human Mesenchymal Stem Cells Processed with Either the FICOLL Method or the BMAC Method

Objective: To compare new bone formation in maxillary sinus augmentation procedures using biomaterial associated with mesenchymal stem cells (MSCs) separated by two different isolation methods. Background: In regenerative medicine open cell concentration systems are only allowed for clinical application under good manufacturing practice conditions. Methods: Mononuclear cells, including MSCs, were concentrated with either the synthetic poylsaccharid (FICOLL) method (classic open system-control group, n = 6 sinus) or the bone marrow aspirate concentrate (BMAC) method (closed system-test group, n = 12 sinus) and transplanted in combination with biomaterial. A sample of the cells was characterized by their ability to differentiate. After 4.1 months (SD +/- 1.0) bone biopsies were obtained and analyzed. Results: The new bone formation in the BMAC group was 19.9% (90% confidence interval [CI], 10.9-29), and in the FICOLL group was 15.5% (90% CI, 8.6-22.4). The 4.4% difference was not significant (90% CI, -4.6-13.5; p = 0.39). MSCs could be differentiated into osteogenic, chondrogenic, and adipogenic lineages. Conclusion: MSCs harvested from bone marrow aspirate in combination with bovine bone matrix particles can form lamellar bone and provide a reliable base for dental implants. The closed BMAC system is suited to substitute the open FICOLL system in bone regeneration procedures.

Subepithelial connective tissue graft for root coverage in smokers and non-smokers: A clinical and histologic controlled study in humans

Background: The aim of this study was to evaluate root coverage of gingival recessions and to compare graft vascularization in smokers and non-smokers. Methods: Thirty subjects, 15 smokers and 15 non-smokers, were selected. Each subject had one Miller Class I or II recession in a non-molar tooth. Clinical measurements of probing depth (PD), relative clinical attachment level (CAL), gingival recession (GR), and width of keratinized tissue (KT) were determined at baseline and 3 and 6 months after surgery. The recessions were treated surgically with a coronally positioned flap associated with a subepithelial connective tissue graft. A small portion of this graft was prepared for immunohistochemistry. Blood vessels were identified and counted by expression of factor VIII-related antigen-stained endothelial cells. Results: Intragroup analysis showed that after 6 months there a was gain in CAL, a decrease in GR, and an increase in KT for both groups (P<0.05), whereas changes in PD were not statistically significant. Smokers had less root coverage than non-smokers (58.02% +/- 19.75% versus 83.35% +/- 18.53%; P<0.05). Furthermore, the smokers had more GR (1.48 +/- 0.79 mm versus 0.52 +/- 0.60 mm) than the nonsmokers (P<0.05). Histomorphometry of the donor tissue revealed a blood vessel density of 49.01 +/- 11.91 vessels/200x field for non-smokers and 36.53 +/- 10.23 vessels/200x field for smokers (P<0.05). Conclusion: Root coverage with subepithelial connective tissue graft was negatively affected by smoking, which limited and jeopardized treatment results.

Comparison between two surgical techniques for root coverage with an acellular dermal matrix graft

Aim: The aim of this randomized, controlled, clinical study was to compare two surgical techniques with the acellular dermal matrix graft (ADMG) to evaluate which technique could provide better root coverage. Material and Methods: Fifteen patients with bilateral Miller Class I gingival recession areas were selected. In each patient, one recession area was randomly assigned to the control group, while the contra-lateral recession area was assigned to the test group. The ADMG was used in both groups. The control group was treated with a broader flap and vertical-releasing incisions, and the test group was treated with the proposed surgical technique, without releasing incisions. The clinical parameters evaluated before the surgeries and after 12 months were: gingival recession height, probing depth, relative clinical attachment level and the width and thickness of keratinized tissue. Results: There were no statistically significant differences between the groups for all parameters at baseline. After 12 months, there was a statistically significant reduction in recession height in both groups, and there was no statistically significant difference between the techniques with regard to root coverage. Conclusions: Both surgical techniques provided significant reduction in gingival recession height after 12 months, and similar results in relation to root coverage.

Effects of Early Functional Loading on Maintenance of Free Autogenous Bone Graft and Implant Osseointegration: An Experimental Study in Dogs

Purpose: The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. Materials and Methods: A total of 5 male clogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm x 13.0 mm, Osseospeed; Astra Tech AB, Molndal, Sweden). Two implants at the extremities of the graft were loaded 2 clays after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws inserted in the extremities of the graft. Four weeks later, the fixation screws were replaced with 3 dental implants. The loading procedure (delayed implant placement group) was performed 2 clays later, as described for the simultaneous implant placement sites. The animals were sacrificed 12 weeks after the grafting procedure. Implant stability was measured through resonance frequency analysis. The bone volume and density were assessed on computed tomography. The bone to implant contact and bone area in a region of interest were evaluated on histologic slides. Results: The implant stability quotient showed statistical significance in favor of the delayed loaded grafts (P=.001). The bone-to-implant contact (P=.008) and bone area in a region of interest (P=0.005) were significantly greater in the delayed group. Nevertheless, no difference was found in terms of graft volume and density between the early loaded and delayed-loaded approaches. Conclusions: The protocol in which the implant and bone graft were given delayed loading allows for effective quality of implant osseointegration and stabilization, with healing and remodeling occurring in areas near the implant resulting in denser bone architecture. (C) 2010 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Sing 68:825-832, 2010

Immunohistochemical, tomographic and histological study on onlay bone graft remodeling. Part II: calvarial bone

Objectives Little information is available on the molecular events that occur during graft incorporation over time. The calvarial bone (Cb) grafts have been reported to produce greater responses compared with other donor regions in maxillofacial reconstructions, but the scientific evidences for this are still lacking. The objectives of this study are (1) to study the morphological pattern of Cb onlay bone grafts and compare them with the biological events through immunohistochemical responses and (2) to establish the effects of perforations in maintaining the volume and bone density of the receptor bed. Material and methods Sixty New Zealand White rabbits were submitted to Cb onlay bone grafts on the mandible. In 30 rabbits, the receptor bed was perforated (perforated group), while for the remaining animals the bed was kept intact (non-perforated group). Six animals from each group were sacrificed at 5, 7, 10, 20 and 60 days after surgery. Histological sections from the grafted area were prepared for immunohistochemical and histological analyses. Immuno-labeling was found for proteins Osteoprotegerin (OPG), receptor activator of nuclear factor-kappa beta ligand (RANKL), alkaline phosphatase (ALP), osteopontin (OPN), vascular endothelial growth factor (VEGF), tartrate-resistant acid phosphatase (TRAP), Type I collagen (COL I) and osteocalcin (OC). The tomography examination [computerized tomography (CT) scan] was conducted just after surgery and at the sacrifice. Results The histological findings revealed that the perforations contributed to higher bone deposition during the initial stages at the graft-receptor bed interface, accelerating the graft incorporation process. The results of the CT scan showed lower resorption for the perforated group (P < 0.05), and both groups showed high bone density rates at 60 days. This set of evidences is corroborated by the immunohistochemical outcomes indicating that proteins associated with revascularization and osteogenesis (VEGF, OPN, TRAP and ALP) were found in higher levels in the perforated group. Conclusions These findings indicate that the bone volume of calvarial grafts is better maintained when the receptor bed is perforated, probably resulting from more effective graft revascularization and greater bone deposition. The process of bone resorption peaked between 20 and 60 days post-operatively in both groups although significantly less in the perforated group. To cite this article:Pedrosa Jr WF, Okamoto R, Faria PEP, Arnez MFM, Xavier SP, Salata LA. Immunohistochemical, tomographic and histological study on onlay bone grafts remodeling. Part II: calvarial bone.Clin. Oral Impl. Res. 20, 2009; 1254-1264.doi: 10.1111/j.1600-0501.2009.01747.x.

A Clinical Study of 406 Sinus Augmentations With 100% Anorganic Bovine Bone

Background: The aim of the present study is to evaluate the use of anorganic bovine bone (ABB) associated with a collagen membrane (CM) for a sinus graft by means of clinical, histologic, and radiographic parameters in cases with bone availability <= 7 mm. A preliminary evaluation consisted of a clinical examination, computed tomography (CT), and a panoramic x-ray. Methods: Ninety-two patients requiring bilateral sinus grafts and 222 requiring unilateral procedures (total: 406 sinuses) participated in this study. A total of 1,025 implants were placed in the grafted sinuses. A total of 118 implants were placed simultaneously with the sinus graft (one stage), and 907 implants were placed in a subsequent surgery (two stages), 6 to 12 months after the graft was performed. In seven cases, a biopsy was harvested for histomorphometric analysis. Recall appointments were scheduled every 6 months, and panoramic and periapical x-rays were required every year for 3 years. Results: Among 1,025 implants, 19 were lost (survival rate: 98.1%). The difference in survival rates for implants placed in native bone: <= 3 mm (98.1%), >3 to <= 5 mm (98.6%), and >5 to <= 7 mm (97.0%) was not statistically significant (P = 0.3408). The survival rates for implants with rough and machined surfaces (98.6% and 97.0%, respectively) were not statistically significant (P = 0.0840). The histomorphometric analysis showed new bone formation (39.0% +/- 12%), marrow space (52.9% +/- 9.3%), and residual ABB (8% +/- 2.7%). Conclusion: Our results indicated that 1,025 implants placed in sinuses grafted exclusively with ABB combined with CM led to an excellent and predictable survival rate of 98.1%. J Periodontol 2009;80:1920-1927.

An artificial nanoemulsion carrying paclitaxel decreases the transplant heart vascular disease: A study in a rabbit graft model

Objective: In previous studies cholesterol-rich nanoemulsions (LDE) resembling low-density lipoprotein were shown to concentrate in atherosclerotic lesions of rabbits. Lesions were pronouncedly reduced by treatment with paclitaxel associated with LDE. This study aimed to test the hypothesis of whether LDE-paclitaxel is able to concentrate in grafted hearts of rabbits and to ameliorate coronary allograft vasculopathy after the transplantation procedure. Methods: Twenty-one New Zealand rabbits fed 0.5% cholesterol were submitted to heterotopic heart transplantation at the cervical position. All rabbits undergoing transplantation were treated with cyclosporin A (10 mg . kg(-1) . d(-1) by mouth). Eleven rabbits were treated with LDE-paclitaxel (4 mg/kg body weight paclitaxel per week administered intravenously for 6 weeks), and 10 control rabbits were treated with 3 mL/wk intravenous saline. Four control animals were injected with LDE labeled with [(14)C]-cholesteryl oleate ether to determine tissue uptake. Results: Radioactive LDE uptake by grafts was 4-fold that of native hearts. In both groups the coronary arteries of native hearts showed no stenosis, but treatment with LDE-paclitaxel reduced the degree of stenosis in grafted hearts by 50%. The arterial luminal area in grafts of the treated group was 3-fold larger than in control animals. LDE-paclitaxel treatment resulted in a 7-fold reduction of macrophage infiltration. In grafted hearts LDE-paclitaxel treatment reduced the width of the intimal layer and inhibited the destruction of the medial layer. No toxicity was observed in rabbits receiving LDE-paclitaxel treatment. Conclusions: LDE-paclitaxel improved posttransplantation injury to the grafted heart. The novel therapeutic approach for heart transplantation management validated here is thus a promising strategy to be explored in future clinical studies. (J Thorac Cardiovasc Surg 2011;141:1522-8)

Maximal inflammatory response benefits syngeneic skin graft acceptance

Objective: We investigated the influence of acute inflammation in skin isograft acceptance. Methods: Two mouse lines selected for maximal (AIR(MAX)) or minimal inflammatory response (AIR(MIN)) were transplanted with syngeneic skin. Cellular infiltrates and cytokine production were measured 1, 3, 7 or 14 days post-transplantation. The percentage of CD4(+) CD25(+) Foxp3(+) cells in the lymph nodes was also evaluated. Results: Grafts were totally accepted in 100% of AIR(MAX) and in 26% of AIR(MIN) mice. In the latter, partial acceptance was observed in 74% of the animals. Emigrated cells were basically PMN and were enhanced in AIR(MAX) transplants. IL-10 production by graft infiltrating cells showed no interline differences. IFN-gamma was increased in AIR(MIN) grafts at day 14 and lower percentages of CD4(+)CD25(+)Foxp3(+) cells in the lymph nodes were observed in these mice. Conclusions: Our data suggest that differences in graft acceptance might be due to a lack of appropriate regulation of the inflammatory response in AIR(MIN) mice compromising the self/non-self recognition.

Assessment the Health Hazard from (222)Rn in Old Metalliferous Mines in San Luis, Argentina

Radon levels in two old mines in San Luis, Argentina, are reported and analyzed. The radiation dose and environmental health risk of (222)Rn concentrations to both guides and visitors were estimated. CR-39 nuclear track detectors were used for this purpose. The values for the (222)Rn concentration at each monitoring site ranged from 0.43 +/- 0.04 to 1.48 +/- 0.12 kBq m(-3) in the Los Cndores wolfram mine and from 1.8 +/- 0.1 to 6.0 +/- 0.5 kBq center dot m(-3) in the La Carolina gold mine, indicating that, in this mine, the radon levels exceed up to four times the action level of 1.5 kBq m(-3) recommended by the International Commission on Radiological Protection. The patterns of the radon transport process revealed that the La Carolina gold mine can be interpreted as a gas confined into a single tube with constant cross-section and air velocity. Patterns of radon activity, taking into account the chimney-effect winds, were used to detect tributary currents of air from shafts or larger fissures along the main adit of the Los Cndores mine, showing that radon can be used as an important tracer of tributary air currents stream out from fissures and smaller voids in the rock of the mine.