Growth Factors Polymerized Within Fibrin Hydrogel Promote Amylase Production in Parotid Cells

Abstract

Salivary gland cell differentiation has been a recurring challenge for researchers as primary salivary cells show a loss of phenotype in culture. Particularly, parotid cells show a marked decrease in amylase expression, the loss of tight junction organization and proper cell function. Previously, Matrigel has been used successfully as an extracellular matrix; however, it is not practical for in vivo applications as it is tumorigenic. An alternative method could rely on the use of fibrin hydrogel (FH), which has been used extensively in biomedical engineering applications ranging from cardiovascular tissue engineering to wound-healing experiments. Although several groups have examined the effects of a three-dimensional (3D) environment on salivary cell cultures, little is known about the effects of FH on salivary cell cultures. The current study developed a 3D cell culture model to support parotid gland cell differentiation using a combination of FH and growth factor-reduced Matrigel (GFR-MG). Furthermore, FH polymerized with a combination of EGF and IGF-1 induced formation of 3D spheroids capable of amylase expression and an agonist-induced increase in the intracellular Ca 2 + concentration ([Ca 2 + ] i ) in salivary cells. These studies represent an initial step toward the construction of an artificial salivary gland to restore salivary gland dysfunction. This is necessary to reduce xerostomia in patients with compromised salivary function.

Development of Poly(Ethylene Glycol) Hydrogels for Salivary Gland Tissue Engineering Applications

“…In contrast to threedimensional (3D) studies performed with fibrin 22 and hyaluronic acid, 20,23,25 PEG is a bio-inert material 26 that can be modified to provide specific biological cues in a novel ''bottom up'' approach to tissue engineering. Numerous ECM proteins that are important to salivary gland development and differentiation have been identified, 106 and some of these such as laminin-111 21 and perlecan 23 have been incorporated into biomaterials.…”

“…Numerous studies have focused on feasibility of using nanofibers or hydrogel-based scaffolds. [15][16][17][18][19][20][21][22][23][24][25] Although a few studies have translated their findings in vivo, 16,17,23 no study to date has demonstrated that the tissue developed on or within biomaterials contributes to restoration of gland function. To overcome these limitations, we propose use of poly(ethylene glycol) (PEG) hydrogels for salivary gland cell transplantation.…”

Expression of Resolvin D1 Biosynthetic Pathways in Salivary Epithelium

“…Western blot analyses were performed as described previously (McCall et al, 2013) and detailed in the Appendix Methods.…”

A systems biology approach identifies a gene regulatory network in parotid acinar cell differentiation.

“…Unfortunately, matrigel cannot be used for in vivo applications as it is derived from a mouse sarcoma cell line [66] and several studies have found it to be tumorigenic [67][68][69]. Culturing cells on fibrin hydrogels has been investigated, but it has failed to produce the same three dimensional morphology [67].…”

“…Culturing cells on fibrin hydrogels has been investigated, but it has failed to produce the same three dimensional morphology [67]. As an alternative technique, one group has developed precisely constructed craters lined with poly-lactic-co-glycolic acid (PLGA) nanofibers to mimic a basement membrane.…”