Stiffening of human skin fibroblasts with age.
Changes in mechanical properties are an essential characteristic of the aging process of human skin. Previous studies attribute these changes predominantly to the altered collagen and elastin organization and density of the extracellular matrix. Here, we show that individual dermal fibroblasts also exhibit a significant increase in stiffness during aging in vivo. With the laser-based optical cell stretcher we examined the viscoelastic biomechanics of dermal fibroblasts isolated from 14 human donors aged 27 to 80. Increasing age was clearly accompanied by a stiffening of the investigated cells. We found that fibroblasts from old donors exhibited an increase in rigidity of ∼60% with respect to cells of the youngest donors. A FACS analysis of the content of the cytoskeletal polymers shows a shift from monomeric G-actin to polymerized, filamentous F-actin, but no significant changes in the vimentin and microtubule content. The rheological analysis of fibroblast-populated collagen gels demonstrates that cell stiffening directly results in altered viscoelastic properties of the collagen matrix. These results identify a new mechanism that may contribute to the age-related impairment of elastic properties in human skin. The altered mechanical behavior might influence cell functions involving the cytoskeleton, such as contractility, motility, and proliferation, which are essential for reorganization of the extracellular matrix.
Schulze
Christian
C
Department of Physics, University of Leipzig, Germany. chr-s@gmx.de
Wetzel
Franziska
F
Kueper
Thomas
T
Malsen
Anke
A
Muhr
Gesa
G
Jaspers
Soeren
S
Blatt
Thomas
T
Wittern
Klaus-Peter
KP
Wenck
Horst
H
Käs
Josef A
JA
D000199:Actins / Q000737:chemistry; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena; D003599:Cytoskeleton / Q000378:metabolism; D004548:Elasticity; D005260:Female; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D055595:Mechanical Phenomena; D046210:Microfluidic Analytical Techniques; D008875:Middle Aged; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012212:Rheology; D012867:Skin / Q000166:cytology*; D013997:Time Factors; D055815:Young Adult
D000199:Actins