Header

UZH-Logo

Maintenance Infos

Effect of Sustained Joint Loading on TMJ Disc Nutrient Environment


Wu, Y; Cisewski, S E; Coombs, M C; Brown, M H; Wei, F; She, X; Kern, M J; Gonzalez, Y M; Gallo, L M; Colombo, V; Iwasaki, L R; Nickel, J C; Yao, H (2019). Effect of Sustained Joint Loading on TMJ Disc Nutrient Environment. Journal of Dental Research, 98(8):888-895.

Abstract

The temporomandibular joint (TMJ) disc nutrient environment profoundly affects cell energy metabolism, proliferation, and biosynthesis. Due to technical challenges of in vivo measurements, the human TMJ disc extracellular nutrient environment under load, which depends on metabolic rates, solute diffusion, and disc morphometry, remains unknown. Therefore, the study objective was to predict the TMJ disc nutrient environment under loading conditions using combined experimental and computational modeling approaches. Specifically, glucose consumption and lactate production rates of porcine TMJ discs were measured under varying tissue culture conditions ( n = 40 discs), and mechanical strain-dependent glucose and lactate diffusivities were measured using a custom diffusion chamber ( n = 6 discs). TMJ anatomy and loading area were obtained from magnetic resonance imaging of healthy human volunteers ( n = 11, male, 30 ± 9 y). Using experimentally determined nutrient metabolic rates, solute diffusivities, TMJ anatomy, and loading areas, subject-specific finite element (FE) models were developed to predict the 3-dimensional nutrient profiles in unloaded and loaded TMJ discs (unloaded, 0% strain, 20% strain). From the FE models, glucose, lactate, and oxygen concentration ranges for unloaded healthy human TMJ discs were 0.6 to 4.0 mM, 0.9 to 5.0 mM, and 0% to 6%, respectively, with steep gradients in the anterior and posterior bands. Sustained mechanical loading significantly reduced nutrient levels ( P < 0.001), with a critical zone in which cells may die representing approximately 13.5% of the total disc volume. In conclusion, this study experimentally determined TMJ disc metabolic rates, solute diffusivities, and disc morphometry, and through subject-specific FE modeling, revealed critical interactions between mechanical loading and nutrient supply and metabolism for the in vivo human TMJ disc. The results suggest that TMJ disc homeostasis may be vulnerable to pathological loading (e.g., clenching, bruxism), which impedes nutrient supply. Given difficulties associated with direct in vivo measurements, this study provides a new approach to systematically investigate homeostatic and degenerative mechanisms associated with the TMJ disc.

Abstract

The temporomandibular joint (TMJ) disc nutrient environment profoundly affects cell energy metabolism, proliferation, and biosynthesis. Due to technical challenges of in vivo measurements, the human TMJ disc extracellular nutrient environment under load, which depends on metabolic rates, solute diffusion, and disc morphometry, remains unknown. Therefore, the study objective was to predict the TMJ disc nutrient environment under loading conditions using combined experimental and computational modeling approaches. Specifically, glucose consumption and lactate production rates of porcine TMJ discs were measured under varying tissue culture conditions ( n = 40 discs), and mechanical strain-dependent glucose and lactate diffusivities were measured using a custom diffusion chamber ( n = 6 discs). TMJ anatomy and loading area were obtained from magnetic resonance imaging of healthy human volunteers ( n = 11, male, 30 ± 9 y). Using experimentally determined nutrient metabolic rates, solute diffusivities, TMJ anatomy, and loading areas, subject-specific finite element (FE) models were developed to predict the 3-dimensional nutrient profiles in unloaded and loaded TMJ discs (unloaded, 0% strain, 20% strain). From the FE models, glucose, lactate, and oxygen concentration ranges for unloaded healthy human TMJ discs were 0.6 to 4.0 mM, 0.9 to 5.0 mM, and 0% to 6%, respectively, with steep gradients in the anterior and posterior bands. Sustained mechanical loading significantly reduced nutrient levels ( P < 0.001), with a critical zone in which cells may die representing approximately 13.5% of the total disc volume. In conclusion, this study experimentally determined TMJ disc metabolic rates, solute diffusivities, and disc morphometry, and through subject-specific FE modeling, revealed critical interactions between mechanical loading and nutrient supply and metabolism for the in vivo human TMJ disc. The results suggest that TMJ disc homeostasis may be vulnerable to pathological loading (e.g., clenching, bruxism), which impedes nutrient supply. Given difficulties associated with direct in vivo measurements, this study provides a new approach to systematically investigate homeostatic and degenerative mechanisms associated with the TMJ disc.

Statistics

Citations

Dimensions.ai Metrics
1 citation in Web of Science®
1 citation in Scopus®
Google Scholar™

Altmetrics

Downloads

3 downloads since deposited on 30 Jan 2020
3 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Center for Dental Medicine > Clinic for Masticatory Disorders
Dewey Decimal Classification:610 Medicine & health
Scopus Subject Areas:Health Sciences > General Dentistry
Language:English
Date:1 July 2019
Deposited On:30 Jan 2020 14:07
Last Modified:29 Jul 2020 13:36
Publisher:Sage Publications
ISSN:0022-0345
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1177/0022034519851044

Download

Closed Access: Download allowed only for UZH members

Content: Published Version
Language: English
Filetype: PDF - Registered users only
Size: 680kB
View at publisher