Graduation Date

Spring 5-2-2024

Document Type


Degree Name

Master of Science (MS)


Medical Sciences Interdepartmental Area

First Advisor

Amy Killeen, DDS, MS

Second Advisor

Richard Reinhardt, DDS, PhD


Wound healing is slower in aged patients. Immediately after tooth extraction, fibroblasts are activated to rebuild the ECM, which is later remodeled through the expression of MMPs. Gene expression may be altered in fibroblasts of aged patients leading to deficiencies in ECM deposition and the recruitment and proliferation of immune cells, resulting in a slow-healing fibrotic wound.

Using scRNA-seq, soft tissue was profiled from two healthy patients: one young and one aged at the time of tooth extraction. Two weeks post-extraction, a second soft tissue sample was harvested. Differentially expressed genes were used to identify enriched pathways for each patient. Six cell clusters were identified and assigned based on the gene profiles of each cluster. Three subclusters of fibroblasts were identified: pro-inflammatory fibroblasts (PIFs), anti-inflammatory fibroblasts (AIFs), and gingival mesenchymal stem cells (GMSC).

In the young patient, AIFs were enriched for pathways involved in maintaining the ECM. The expression profile in young PIFs exhibited pro-inflammatory pathways, while the aged PIFs were enriched for ECM pathways like AIFs. The GMSCs of both patients had a significant overlap in differentially expressed genes for cellular homeostasis. This may mean that GMSCs resist age-related changes and could be a source of therapy. At two weeks, the aged patient still expressed genes for ECM production and fibrosis, while the young patient expressed genes associated with proliferation. This indicates that the aged patient was in a prolonged state of inflammation and fibrosis. Differences in fibroblast gene expression suggest that fibroblasts in aged patients may contribute towards a slow-healing fibrotic wound.


2024 Copyright, the authors

Available for download on Thursday, April 10, 2025