Mechanical forces alter extracellular matrix synthesis by human periodontal ligament fibroblasts

Abstract

Periodontal ligament fibroblasts (PDLFs) are a heterogeneous population of cells that are involved in the normal maintenance, repair and regeneration of both the ligament and adjacent hard tissues. Additionally, the ability of these cells to respond to mechanical stimulation suggests that they have a central role in mediating the osseous remodeling that underlies physiological and orthodontic tooth movement. To characterize their role further in this process, the current study evaluated the effect of tensional stress on the biosynthesis of extracellular matrix (ECM) proteins by human PDLFs. Cell strains were established from extracted human premolars and third molars. Cells exposed to 5% biaxial deformation (strain) at a frequency of 30 times/min for 24 hr exhibited statistically significant increases in type I collagen and fibronectin synthesis, and a statistically signficant decrease in tropoelastin production relative to unstretched controls. Cells exposed to 10% strain exhibited similar responses for fibronectin and tropoelastin while the amount of type I collagen synthesized by stretched cells did not differ from control levels. These results indicate that mechanical stimulation of PDLFs alters type I collagen, tropoelastin and fibronectin production and that these cells are differentially responsive to varying levels of mechanical stress. The ability of these cells to alter ECM protein synthesis in response to specific magnitudes of tensional stress may in part explain how PDLFs regulate ligament and hard tissue remodeling.

Effect of Stretching Stress on Gene Transcription Related to Early-phase Differentiation in Rat Periodontal Ligament Cells

“…This supports the studies of Howard et al and He et al and suggests that stretching stress facilitates cellular differentiation of PDL cells into osteoprogenitor cells 3,5,19) . It has been demonstrated that mechanical stretching stress may modulate the increase magnitude-dependently of Col-I synthesis in PDL cells.…”

“…genesis [3][4][5][7][8][9][12][13][14][17][18][19][21][22][23][24][25] , that HSP70 was involved in homeostasis 1,16) , and that bFGF was closely involved in both functions 11,18,20) . Although the magnitude of human bite force varies, 500-3,000 g was selected as the standard force for clinical studies 2) .…”

Pressure and Distortion Regulate Human Mesenchymal Stem Cell Gene Expression

“…8 In general, these two types of stress combine to form the total stress at a particular location. The utility of these classifications is supported by loading experiments on tissues where chondrogenic protein expression in cartilage is up-regulated in response to pressure, 15,22 while structural protein expression is enhanced in fibrous connective tissues in response to distortion. 4,22,23 While the concept that physical factors such as pressure and distortion are involved in tissue modeling and remodeling has become widely accepted, the majority of this evidence has been collected from differentiated cell types or tissue explants.…”

Tensile Stimulation of Murine Stem Cell–Collagen Sponge Constructs Increases Collagen Type I Gene Expression and Linear Stiffness

“…In fact, direct comparison of our results to those used by other investigators was difficult given the broad range of frequencies (0.0167 Hz, 50 0.25 Hz, 55 and 0.167 Hz…”