Abigail Koh

Use of autogenous soft tissue grafts in mucogingival surgery is restricted by increased surgical morbidity and limited availability. Existing cell-free soft tissue substitutes are less effective clinically, highlighting the need for novel alternatives. This study presents fabrication of a tissue-engineered full-thickness vascularized gingival constructs (GC) and evaluation of its engraftment in a mice skin wound model. Vascularized-GCs were fabricated by air-liquid interface (ALI) culture of oral keratinocytes seeded onto a collagen-fibrin scaffold, pre-loaded with gingival fibroblasts and microvascular endothelial cells (ECs). Non-vascularized-GCs were similarly fabricated, excluding the ECs. Both constructs were characterized histologically using a variety of epithelial, basement membrane, and vascular markers. Subsequently, the GCs and cell-free controls were implanted into surgically created, full-thickness skin defects (Ø8mm) on the dorsum of immunodeficient mice. Mice were sacrificed at 1-3 weeks post-implantation for histological evaluation. After 2-weeks ALI culture, the keratinocytes formed a multi-layered, ortho-keratinized epithelium expressing CK5, CK10, CK14, filaggrin and loricrin. While the ECs self-assembled into CD31 and vWF-expressing microvascular networks. Compared to non-vascularized-GCs, the vascularized-GCs should improved epithelial maturation. In vivo, the healing of both vascularized and non-vascularized-GCs resembled surrounding tissues, with minimal wound contraction. In contrast, cell-free controls healed with greater wound contraction. Vascularized-GCs showed rapid revascularization and anastomosis between human and mice microvasculature within 1-week post-implantation. While non-vascularized-GCs and controls showed invasion of murine blood vessels from the graft periphery after 2-week post-implantation. Both types of GCs exhibited rapid epithelial confluence (1-week) as compared to a thin discontinuous epithelial layer in the controls. The in vitro biofabrication platform offers the potential to generate multi-cellular GCs with perfusable microvasculature and rapid engraftment in vivo. Ultimately, this could translate into new treatment alternatives for mucogingival defects and also as an in vitro platform to investigate mucosal biology.

Dr. Abigail Koh is a Registrar at the Department of Restorative Dentistry, National Dental Centre Singapore (NDCS). She obtained her Bachelor of Dental Surgery from the National University of Singapore (NUS) in 2018. During her undergraduate days, she was awarded the NUS Merit Scholarship. Her Undergraduate Research Opportunities Programme (UROP) team was also awarded 2nd Place in the 2018 Dentsply Sirona Student Competition for Advancing Dental Research and its Application (SCADA). Dr. Abigail subsequently pursued advanced studies in Periodontology and completed her Master of Dental Surgery in Periodontology at the National University of Singapore (NUS) in 2023. During her residency, she presented at the 2022 IADR/APR General Session and Exhibition. Her research interests encompass soft tissue augmentation within the realm of implant dentistry and Periodontology, as well as the utilization of tissue-engineered constructs in the regeneration of hard and soft tissue defects.