Evaluation of contractile phenotype in airway smooth muscle cells isolated from endobronchial biopsy and tissue specimens from horses.

OBJECTIVE To develop a method to maintain the initial phenotype of airway smooth muscle (ASM) cells isolated from equine endobronchial biopsy specimens in long-term cell culture. SAMPLE Endobronchial tissue specimens (8 to 10/horse) collected from the lungs of previously healthy horses at necropsy (n = 12) and endobronchial biopsy specimens collected from standing, sedated, heaves-affected horses in clinical remission of the disease (5) and control horses (4). PROCEDURES A sampling protocol was developed to recover and maintain a contractile phenotype in ASM cells from endobronchial specimens from freshly harvested equine lungs and from healthy and heaves-affected horses. Immunologic techniques were used to evaluate the contractile phenotype of ASM cells in culture. RESULTS Characteristic ASM cells were successfully cultured from endobronchial tissue or biopsy specimens from both healthy and heaves-affected horses, and their contractile phenotype was maintained for up to 7 passages. Moreover, the capacity of cells at the seventh passage to contract in a collagen gel in response to methacholine was maintained. CONCLUSIONS AND CLINICAL RELEVANCE ASM cells isolated from equine endobronchial tissue and biopsy specimens were able to maintain a contractile phenotype in long-term cell cultures, suggesting they could be used for tissue engineering and in vitro studies of equine ASM cells.

Potential of skin fibroblasts for application to anterior cruciate ligament tissue engineering.

Fibroblasts isolated from skin and from anterior cruciate ligament (ACL) secrete type I and type III collagens in vivo and in vitro. However, it is much easier and practical to obtain a small skin biopsy than an ACL sample to isolate fibroblasts for tissue engineering applications. Various tissue engineering strategies have been proposed for torn ACL replacement. We report here the results of the implantation of bioengineered ACLs (bACLs), reconstructed in vitro using a type I collagen scaffold, anchored with two porous bone plugs to allow bone-ligament-bone surgical engraftment. The bACLs were seeded with autologous living dermal fibroblasts, and grafted for 6 months in goat knee joints. Histological and ultrastructural observations ex vivo demonstrated a highly organized ligamentous structure, rich in type I collagen fibers and cells. Grafts' vascularization and innervation were observed in all bACLs that were entirely reconstructed in vitro. Organized Sharpey's fibers and fibrocartilage, including chondrocytes, were present at the osseous insertion sites of the grafts. They showed remodeling and matrix synthesis postimplantation. Our tissue engineering approach may eventually provide a new solution to replace torn ACL in humans.

Modulated expression of a nuclear-associated glycoprotein during normal rat liver development and in various hepatoma cells.

Liver plays a major role in systemic detoxification and drug metabolism. NF-164, a protein of 164 kDa predominantly localized in hepatocyte nuclei, was found to be present in increasing amounts during liver maturation. In addition, fetal rat hepatocytes had ten times, and neonatal five times less of this protein than adult hepatocytes. It was also detected in an albumin producing hepatoma cell line, but not in three other lines that have lost several differentiated functions. These data suggest that NF-164 expression is development-dependent and that it may be a marker for both normal and malignant hepatocyte differentiation. NF-164 seems to be liver-specific, since it was not detected in rat brain, spleen, kidney, lung and bovine thymus. It was purified from adult rat hepatocyte nuclei. Its estimated pI is 6.8. Its total amino acid composition and partial amino acid sequence is also being reported. Despite major differences between their respective contents in amino acids, partial sequences showed homologies with carbamyl phosphate synthetase I (CPSI). These observations may suggest that NF-164 also shares some functional features with this enzyme.

Tissue-engineered human asthmatic bronchial equivalents.

The isolation of human bronchial epithelial (HBEC) and fibroblastic cells (HBFC) from biopsies of asthmatic and non-asthmatic volunteers provided unique cellular materials to be used for the production of bioengineered bronchial equivalents (BE) in vitro. The HBEC are grown on a mesenchymal layer seeded with HBFC and the BE can be maintained for at least 15 days in culture. Under the BE culture conditions established previously, HBEC undergo differentiation into ciliated and goblet cells, within a pseudostratified organization comparable to human bronchi. We published previously the results from histologic and functional analyses of such BE produced exclusively using non-asthmatic HBEC and HBFC. We report here the comparative analyses of BE produced with non-asthmatic and asthmatic living HBEC and HBFC (naBE and aBE, respectively). Our data indicated that all asthmatic HBEC populations grown on a mesenchymal layer, containing non-asthmatic HBFC, slowly reached a confluent state but then detached from the matrix upon culture time. These BE appear to be very good models to study the mechanisms involved in asthma in vitro.

[Tissue engineering: a tool to understand the physiological mechanisms]. / Le génie tissulaire au service de la compréhension du vivant.

Tissue engineering is a new domain, which allows some very unique studies of many human physiological mechanisms. This technology, based on cell capacity to reproduce a three-dimensional tissue with or without the help of biomaterials, is an interesting approach to study cells in an environment quite similar to the in vivo context. This article summarizes the LOEX's (laboratory of experimental organogenesis) scientific endeavor in tissue engineering in order to better understand some physiological or pathological mechanisms. Thus wound healing, stem cells, graft vascularization and cell interactions are domains where tissue engineering has already made a significant impact.