Age-Related Changes in the Mechanical Properties of Human Fibroblasts and Its Prospective Reversal After Anti-Wrinkle Tripeptide Treatment

Abstract

One of an essential characteristic of human skin are time dependent mechanical properties. Here, we demonstrate that stiffness of human dermal fibroblast correlates with age and it can be restored after anti-wrinkle tripeptide treatment. The stiffness of human fibroblasts isolated from donors of 30-, 40- and 60 years old were examined. Additionally the effect of anti- wrinkle tripeptide of latter cells was investigated. The atomic force microscopy measurements were performed on untreated fibroblast as well as on treated with the peptide. The Young’s modulus for two indentation depths 200 and 600 nm of each cell type was determined. The Young’s modulus increases with age of the cells. The highest values of Young’s modulus were obtained for fibroblasts collected from 60 years old donors, for indentation depth of ~200 nm. For larger indentation depth of 600 nm there are no significant differences in stiffness between cells. Fibroblasts treated with the anti-wrinkle tripeptide exhibit lower Young’s modulus. The cells derived from 40- and 60-years old donors restored stiffness characteristic to the level of 30 years old subjects. The results show correlation between stiffness and age of the human fibroblast as well as impact of anti-wrinkle tripeptide on the mechanical properties of skin cells.

The Mechanobiology of Aging

“…Indeed, numerous studies have demonstrated that there is a strong correlation between age and cytoplasmic stiffness (i.e., cytoplasmic compliance or deformability is reduced with age) ( Figure 2 ). Studies that have applied AFM to adherent human cells [epithelial cells (37, 42, 73), fibroblasts (38), and cardiac myocytes (40)] seeded on flat substrates have shown that cells consistently respond to mechanical activation with a stiffening response as a function of increasing age. This suggests that age-dependent cytoplasmic stiffening is not cell-type specific.…”

“…In efforts to better understand how to potentially reduce these age-dependent mechanical dysfunctions in cells and tissues, studies have been geared toward assessing the possibility of reversing the mechanical phenotypes of cells derived from elderly individuals (38, 42). Due to the dominating effects of the actin cytoskeleton and the increased F-actin content (38, 39) observed in cells from older donors (i.e., fibroblasts, cardiac myocytes, and red blood cells), a widely studied target for possible phenotypic reversal is the use of pharmacological agents that affect F-actin.…”

“…In efforts to better understand how to potentially reduce these age-dependent mechanical dysfunctions in cells and tissues, studies have been geared toward assessing the possibility of reversing the mechanical phenotypes of cells derived from elderly individuals (38, 42). Due to the dominating effects of the actin cytoskeleton and the increased F-actin content (38, 39) observed in cells from older donors (i.e., fibroblasts, cardiac myocytes, and red blood cells), a widely studied target for possible phenotypic reversal is the use of pharmacological agents that affect F-actin. Studies conducted using the F-actin-depolymerizing drug cytochalasin B and the F-actin-stabilizing drug jasplakinolide indicate that fibroblasts treated with cytochalasin B that were aged in vitro on a dish ( > 50 doublings) regressed to levels of cytoplasmic stiffness comparable to those of earlier passage cells ( < 25 doublings) (42, 73).…”

“…Similarly, human fibroblasts exposed to an antiwrinkle tripeptide demonstrated decreased cytoplasmic stiffness, with larger effects seen in samples from older donors (aged 60 years) relative to samples from younger donors (aged 40 and 30 years). This reversal was partly due to direct effects on the cytoskeleton, primarily F-actin, as seen from changes in the content, structure, and contractility after treatment (38). However, although these studies show evidence of mechanical reversal in vitro by manipulating actin directly, additional studies should be performed to further elucidate and identify reversal in vivo and to evaluate the role of cytoskeletal control on cellular aging.…”

An Overview of Factors Affecting the Skins Youngs Modulus

“…Hara [25] suggested that the Young's Modulus of the epidermis layer of the skin increases with age, while that of the dermis layer remains constant with age. Molak [26] performed experiments using indentation technique and found out that the Young's Modulus increased with age and remained unaltered for the indenter depths of 200 and 600 nm respectively.…”