A novel system supporting acini-like assembly in a 3D culture system was established. Presence of biomarkers and secretion of salivary enzymes confirms functionality in vitro. Future experiments will test the 3D system in an animal model.

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Tissue engineering is a rapidly evolving interdisciplinary field that aims to regenerate new tissue to replace damaged tissues or organs. The extracellular matrix (ECM) of animal tissues is a complex mixture of macromolecules that play an essential instructional role in the development of tissues and organs. Therefore, tissue engineering approaches rely on the need to present the correct cues to cells, to guide them to maintain tissue-specific functions. Recent research efforts have allowed us to mine various sequences and motifs, which play key roles in these guidance functions, from the ECM. Small conserved peptide sequences mined from ECM molecules can mimic some of the biological functions of their large parent molecules. In addition, these peptide sequences can be linked to various biomaterial scaffolds that can provide the cells with mechanical support to ensure appropriate cell growth and aid the formation of the correct tissue structure. The tissue engineering field will continue to benefit from the advent of these mined ECM sequences which have two major advantages over recombinant ECM molecules: material consistency and scalability.

Development of an artificial salivary gland will benefit patients with xerostomia post radiation therapy for upper respiratory cancer. The goal is to devise a 3D culture system in which salivary cells differentiate into polarized acini that express essential biomarkers and directionally secrete ␣-amylase. Differentiated acini-like structures in a 3D biomaterial-based scaffold will mimic salivary gland functions. METHODS: Salivary gland tissue was obtained from patients undergoing surgery. Marker expression established the phenotype of salivary gland cells. Perlecan/HSPG2, an important component of the basement membrane, was largely expressed in the salivary gland tissue. A culture system consisting of hyaluronic acid (HA) hydrogel and a coupled bioactive peptide derived from domain IV of perlecan (PlnDIV) was used. Prior studies demonstrated differentiation of acinar cells into lobular structures that mimicked intact glands when cultured on Pln-DIV peptide coated surfaces. Cells were seeded and allowed to differentiate into acini-like structures. Several strategies are compared: 1) seeding onto hydrogels; 2) encapsulating in sandwich hydrogel; and 3) direct encapsulation. Cell viability and phenotype are compared. RESULTS: Acini-like structures with lumen were stained for the presence of tight junction components such as ZO-1 and E-cadherin, aquaporin-5 water channels and ␣-amylase. Ongoing studies involve studying lumen formation by apoptosis and demonstrating vectorial ␣-amylase secretion into the lumen of the structures. CONCLUSIONS: A novel system supporting acini-like assembly in a 3D culture system was established. Presence of biomarkers and secretion of salivary enzymes confirms functionality in vitro. Future experiments will test the 3D system in an animal model. Esophageal perforation in head and neck cancer patients Nsangou Ghogomu (presenter)