July 2006, Issue 6

The Center for Integrated Tissue Engineering (CITE)

The CITE is a core facility that uses powerful new research tools to create three-dimensional (3D) tissue culture systems that mimic the body’s tissue architecture. Tissue systems can be engineered to simulate biological processes more closely than has been possible with traditional two-dimensional (2D) monolayer cultures in petri dishes. 3D tissue cultures allow investigators to trace the complex interplay between multiple cell and tissue types in normal and diseased tissue. 

3D tissues, as opposed to 2D cell culture, provide a basis for more reliable correlations between in vitro studies and in vivo outcomes during human clinical trials. The CITE can generate normal human tissues as well as tissues that mimic cancerous states in order to provide a “pre-clinical,” experimental setting that can in turn accelerate development in a cost-effective manner of procedures or products for clinical application.  These tissues

• Enable evaluation and development of candidate drugs and compounds in surrogate normal and cancerous human tissue
• Accelerate translational research by validating, in 3D human tissues, disease targets discovered in conventional 2D culture systems
• Provide validated normal human tissue models for product screening that can predict product safety and efficacy in human tissues as alternatives to animal testing.  Assays include tissue penetration, tissue metabolism, phototoxicity, genotoxicity, and irritation

The CITE currently provides the following core services:

Fabrication of human 3D tissues.  This core constructs normal and cancer-like human 3D tissues on various stromal (connective tissue) supports. Cell types that have been incorporated into 3D tissues include mast cells, melanocytes, and bone marrow-derived mesenchymal cells. Currently available tissue types include [1] skin, oral mucosa and "stromal equivalents" that simulate the behavior of adult mesenchymal cells in vivo; [2] human tissue models for wound repair and sun-induced damage; and [3] tissues that mimic various stages of squamous cell carcinoma and breast carcinoma. Tissues incorporating esophageal cells and human embryonic stem cells are being developed and tested. The CITE staff also works with investigators to develop new tissue models that incorporate other cell types as platforms in discovery science.  

Chemical and genetic modification of 3D tissues to identify or validate cellular targets.  3D tissues are amenable to modification either by direct pharmacological manipulation (bioactive compounds in the tissue culture medium) or by genetic manipulation (viral vectors or siRNA).  Modulating the expression or function of specific gene targets in 3D tissues permits investigation of specific pathways in target cells in both normal and cancerous tissue.

Imaging and gene expression analysis of 3D tissues. 3D tissue fabrication provides unique opportunities to analyze readouts that reflect the importance of tissue context in studies of disease-associated pathways. Routine analyses performed in this core include 3D tissue processing, sectioning of frozen or paraffin-embedded tissues, immunohistochemical staining, and hematoxylin and eosin staining. Phenotypic analyses include [1] cell proliferation (BrdU incorporation), [2] differentiation markers by immunohistochemical staining, [3] cell death (TUNEL assay), and [4] immunohistochemical localization of cell adhesion (cell-cell and cell-matrix proteins) for analyzing alterations in tissue structure. Genomic and proteomic analyses can also be integrated into this repertoire through links with other core facilities.

The CITE is housed in the laboratory of Jonathan Garlick, DDS, PhD, director of the Division of Cancer Biology and Tissue Engineering, Tufts University School of Dental Medicine. It is located on the Boston Health Sciences Campus in the South Cove Building at 55 Kneeland Street (Room 116). The associate director of the CITE is Christophe Egles, PhD. Yulia Shamis, MSc, oversees all tissue processing and analysis within the Histology Unit at the CITE. 

For more information, please go to http://www.tufts.edu/central/research/CITE.htm