Researcher(s)
- Benjamin Abraham, Biomedical Engineering, University of Delaware
Faculty Mentor(s)
- Xinqiao Jia, Material Science and Engineering, University of Delaware
- Liyun Wang, Mechanical Engineering, University of Delaware
Abstract
Radiation therapy for head and neck cancers irreversibly damages the saliva-producing acinar cells in the salivary glands, causing dry mouth disease, or xerostomia. Patients with radiation-induced xerostomia face oral complications and reduced quality of life. Currently, clinicians treat xerostomia using stimulants that promote secretion from existing, damaged salivary gland tissue, yet no long-term solution exists for tissue regeneration that would allow patients to return to prior baseline function. Therefore, an implantable and biocompatible synthetic matrix can provide a platform for tissue regeneration. Previously, it was established that proper vascular development is vital for proper salivary gland regeneration, so our implanted Hyaluronic acid-based (HA) hydrogels should allow for angiogenesis. Here, we conducted an in vivo study investigating implanted thiolated HA hydrogel performance following partial resection of rat parotid salivary gland, observing the gel’s impact 7, 28, and 56 days post-implantation. We also compared bulk versus freeze-dried (cryogels) hydrogels and investigated the effect of angiogenic growth factors. The excised gland and implant tissue underwent histological analysis via Hematoxylin & Eosin and Gomori’s Trichrome staining to visualize how the rat salivary gland responds, recovers, and grows from the implanted hydrogel. Immunohistological staining was also performed using three antibodies analyzing distinct aspects of the tissue response: CD31, an endothelial cell marker; α-SMA, a myoepithelial marker; and CD206/F4/80, an M2 macrophage marker. Together, these markers allow us to assess whether the implanted gels are tolerated by the host and support vascular ingrowth and tissue recovery. We hypothesize that growth-factor soaked cryogels will best support vascularization and tissue integration compared to bulk hydrogels. Overall, these findings will help establish design criteria for HA-based hydrogels as a long-term implantable treatment for radiation-induced xerostomia.