Award Date

May 2024

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Dental Medicine

First Committee Member

John Colombo

Second Committee Member

Jeffrey Ebersole

Third Committee Member

Jessica Immonen

Fourth Committee Member

Courtney Coughenour

Number of Pages

52

Abstract

Background: The gaining popularity of electronic nicotine delivery systems (ENDS) and inhaling aerosols (“vaping”) among young people have exposed them to unprecedented amounts of nicotine. Fourth generation ENDS manufacturers attract the adolescent demographic with a smooth vaping experience with enticing flavors such as “Piña Colada” or “Peppermint Blast.” Components of e-liquids in cartridges of ENDS combine protonated nicotine, also referred as nicotine salts, with flavors in a propylene glycol or vegetable glycerin solvent. Unregulated, high amounts of nicotine in ENDS products have been associated with increased levels of nicotine in the circulating blood of users with an average concentration of about 30ng/mL. Little is known on the effects of protonated nicotine on oral health, specifically on stem cells from human exfoliated deciduous teeth (SHED) and dental pulp stem cells (DPSC), and its implications on the repair and regeneration processes for the soft and hard tissues.Objectives: The aim of this study is to evaluate the effects of nicotine on SHED and DPSC cell growth, surface marker expression, and osteogenic differentiation capacity. Methods: Isolated SHED cells and DPSC cells were seeded in separate T-75 flasks with culture medium treated with 0ng/mL, 30ng/mL, and 300ng/mL of concentrated protonated nicotine. Population doublings were recorded over several passages once confluency was reached. The antigen surface marker expressions of SHED and DPSC sample populations were analyzed using flow cytometry. SHED and DPSC cell populations were cultured in osteogenic induction media, then after 7 days, collected for RNA Isolation and RT-qPCR gene expression of runt-related transcription factor 2 (RUNX2), secreted phosphoprotein 1 (SPP1), and bone gammacarboxyglutamate protein (BGLAP). Results: Population doublings showed significant decrease in growth rate of both 30ng/mL and 300ng/mL nicotine treated SHED and DPSC cell populations compared to the untreated controls. Cell surface marker expression of nicotine treated SHEDs and DPSCs were consistent with the typical presentation of human mesenchymal stem cells (MSC). Analysis of cell populations from 0ng/mL, 30ng/mL and 300ng/mL nicotinic concentrations cultured in osteoblast inducing media using qPCR revealed no changes in RUNX2, SPP1 and BGLAP gene expression compared to undifferentiated controls. Conclusion: Nicotine exhibits an adverse effect on the proliferation rate of SHEDs and DPSCs but shows no effect on their stem cell marker expression and osteogenic differentiation capacity.

Keywords

dental stem cells; differentiation; electronic cigarrettes; nicotine; osteoblast; osteogenic

Disciplines

Dentistry

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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