Extracellular matrix and fibroblast injection produces pterygium-like lesion in rabbits

BACKGROUND: Translational research to develop pharmaceutical and surgical treatments for pterygium requires a reliable and easy to produce animal model. Extracellular matrix and fibroblast are important components of pterygium. The aim of this study was to analyze the effect of the subconjunctival injection of fibroblast cells (NIH3T3 cell line) and exogenous extracellular matrix in rabbits in producing a pterygium-like lesion. METHODS: Six 3-month-old white New Zealand rabbits were injected with 20,000 NIH3T3 cells and 5 µL of Matrigel in the right conjunctiva, and with only 5 µL of Matrigel in the left conjunctiva. The eyes were photographed under a magnification of 16× using a 12-megapixel digital camera attached to the microscope on day 1,3 and 7. Conjunctival vascularization was measured by analyzing images to measure red pixel saturation. Area of corneal and conjunctival fibrovascular tissue formation on the site of injection was assessed by analyzing the images on day 3 and 7 using area measurement software. Histopathologic characteristics were determined in the rabbit tissues and compared with a human primary pterygium. RESULTS: The two treatments promoted growth of conjunctival fibrovascular tissue at day 7. The red pixel saturation and area of fibrovascular tissue developed was significantly higher in right eyes (p < 0.05). Tissues from both treatments showed neovascularization in lesser extent to that observed in human pterygium. Acanthosis, stromal inflammation, and edema were found in tissues of both treatments. No elastosis was found in either treatment. CONCLUSIONS: Matrigel alone or in combination with NIH3T3 cells injected into the rabbits' conjunctiva can promote tissue growth with characteristics of human pterygium, including neovascularization, acanthosis, stromal inflammation, and edema. The combination of Matrigel with NIH3T3 cells seems to have an additive effect on the size and redness of the pterygium-like tissue developed.

Aplicación de biomateriales de base biológica, moléculas bioactivas e ingeniería de tejidos en cirugía plástica periodontal: una revisión / Application of biological based biomaterials, bioactive molecules and tissue engineering in periodontal plastic surgery. A review

Objetivo: Describir, clasificar y discutir las indicaciones de los biomateriales de base biológica, moléculas bioactivas e ingeniería de tejidos que se están usando para el manejo de recesiones y aumento de encía en cirugía plástica periodontal. En esta revisión de la literatura, se utilizó una combinación de los términos de búsqueda específicos que consideraran los materiales en revisión, para el aumento de encía adherida, y el recubrimiento radicular. Materiales y Métodos: Se usaron las siguientes fuentes: Medline, Biblioteca Cochrane, y búsqueda manual de revistas específicas como el Journal of Periodontology, International Journal of Periodontics and Restorative Dentistry y Journal of Clinical Periodontology entre años 1985 y 2011. Se revisaron un total de 117 artículos y se seleccionaron 74 entre estudios clínicos controlados, estudios clínicos randomizados, reportes de casos y estudios en animales. Los artículos fueron revisados por los autores y aceptados por consenso para su discusión. Conclusiones: 1) Existe una serie de materiales que presentan gran potencial y podrían ser una alternativa viable a los injertos autógenos, pero se requiere más estudios a largo plazo. 2) Existe necesidad de estudios con la investigación de estos procedimientos en relación a resultados orientados a la estabilidad, seguridad y efectividad de los diferentes materiales existentes.

Objective: To describe, classify and discuss the clinical applications of biologically based biomaterials, bioactive molecules and tissue engineering being utilized in gingival recession therapy and gingival augmentation procedures in plastic periodontal surgery. In this literature review, a combination of specific search key words were used, including materials being reviewed, indicated for gingival augmentation and root coverage procedures. Materials and Methods: The following sources were consulted: Medline, Cochrane Library and manual search of specific scientific journals such as Journal of Periodontology, International Journal of Periodontics and Restorative Dentistry and Journal of Clinical Periodontology between the years 1985 and 2011. A total of 117 articles were reviewed with 74 being selected unanimously by the authors for discussion in the manuscript. These articles included controlled clinical studies, randomized clinical studies, case reports and animal studies. The selected articles were reviewed by the authors and accepted by consensus. Conclusions: 1) There is a cohort of materials that exhibit great potential which could be a viable alternative to autografts but are in need of further long term studies. 2) There is a need of research of these materials in relation to stability, safety and efficacy.

Use of a latex biomembrane for bladder augmentation in a rabbit model: biocompatibility, clinical and histological outcomes

PURPOSE: To investigate histological features and biocompatibility of a latex biomembrane for bladder augmentation using a rabbit model. MATERIAL AND METHODS: After a partial cystectomy, a patch of a non-vulcanized latex biomembrane (2x4 cm) was sewn to the bladder with 5/0 monofilament polydioxanone sulfate in a watertight manner. Groups of 5 animals were sacrificed at 15, 45 and 90 days after surgery and the bladder was removed. The 5-µm preparations obtained from grafted area and normal bladder were stained with hematoxylin-eosin. Immunohistochemical staining was performed with a primary antibody against alpha-actin to assess muscle regeneration. RESULTS: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. Macroscopically, after 90 days, the latex biomembrane was not identifiable and the patch was indistinguishable from normal bladder. A bladder stone was found in one animal (6.6 percent). On the 90th day, histology revealed continuity of transitional epithelium of host bladder tissue on the patch area. At this time, the muscle layers were well organized in a similar fashion to native bladder muscle layers. The inflammatory process was higher on grafted areas when compared to controls: 15 days - p < 0.0001, 45 days - p < 0.001, and 90 days - p < 0.01. The anti alpha-actin immunoexpression peaked at 45 days, when the graft was observed covered by muscle cells. CONCLUSION: The latex biomembrane is biocompatible and can be used in models for bladder augmentation in rabbits. It promotes epithelium and muscle regeneration without urinary leakage.

Resorbable extracellular matrix grafts in urologic reconstruction

PURPOSE: There is an increasingly large body of literature concerning tissue-engineering products that may be used in urology. Some of these are quite complex (such as multilayer patient-specific cell-seeded implants) yet the most simple and successful products to date are also the most uncomplicated: resorbable acellular extra-cellular matrices (ECMs) harvested from animals. ECMs have been used in a variety of difficult urologic reconstruction problems, and this review is intended to summarize this complex literature for the practicing urologist. METHODS: Medline search of related terms such as "SIS, small intestinal submucosa, ECM, extracellular matrix, acellular matrix and urologic reconstruction". Manuscripts missed in the initial search were taken from the bibliographies of the primary references. RESULTS: Full review of potential clinical uses of resorbable extra-cellular matrices in urologic reconstruction. CONCLUSIONS: Currently, the "state of the art" in tissue engineering solutions for urologic reconstruction means resorbable acellular xenograft matrices. They show promise when used as a pubovaginal sling or extra bolstering layers in ureteral or urethral repairs, although recent problems with inflammation following 8-ply pubovaginal sling use and failures after 1- and 4-ply SIS repair of Peyronie's disease underscore the need for research before wide adoption. Preliminary data is mixed concerning the potential for ECM urethral patch graft, and more data is needed before extended uses such as bladder augmentation and ureteral replacement are contemplated. The distant future of ECMs in urology likely will include cell-seeded grafts with the eventual hope of producing "off the shelf" replacement materials. Until that day arrives, ECMs only fulfill some of the requirements for the reconstructive urologist.