Hyaluronan concentration within a 3D collagen matrix modulates matrix viscoelasticity, but not fibroblast response

Abstract

The use of 3D extracellular matrix (ECM) microenvironments to deliver growth-inductive signals for tissue repair and regeneration requires an understanding of the mechanisms of cell-ECM signaling. Recently, hyaluronic acid (HA) has been incorporated in collagen matrices in an attempt to recreate tissue specific microenvironments. However, it is not clear how HA alters biophysical properties (e.g. fibril microstructure and mechanical behavior) of collagen matrices or what impact these properties have on cell behavior. The present study determined the effects of varying high molecular weight HA concentration on 1) the assembly kinetics, fibril microstructure, and viscoelastic properties of 3D type I collagen matrices and 2) the response of human dermal fibroblasts, in terms of morphology, F-actin organization, contraction, and proliferation within the matrices. Results showed increasing HA concentration up to 1 mg/ml (HA:collagen ratio of 1:2) did not significantly alter fibril microstructure, but did significantly alter viscoelastic properties, specifically decreasing shear storage modulus and increasing compressive resistance. Interestingly, varied HA concentration did not significantly affect any of the measured fibroblast behaviors. These results show that HA-induced effects on collagen matrix viscoelastic properties result primarily from modulation of the interstitial fluid with no significant change to the fibril microstructure. Furthermore, the resulting biophysical changes to the matrix are not sufficient to modulate the cell-ECM mechanical force balance or proliferation of resident fibroblasts. These results provide new insight into the mechanisms by which cells sense and respond to microenvironmental cues and the use of HA in collagen-based biomaterials for tissue engineering.

The effect of hyaluronan on the motility of skin dermal fibroblasts in nanofibrous scaffolds

“…Cells grew well on nanofibers, however, there were no significant differences in cell number or viability on the PCL, PCL/HA 5:1, and PCL/HA 5:2 scaffolds. It has been previously proposed that when HA has a low molecular weight (LMWHA), there is a positive effect on its mitogenic properties, while HA with a high molecular weight (HMWHA), as used in this study, inhibits cell growth [25,26]. However, HMWHA has an increased ability to bind fibrinogen, which is a critical glycoprotein in early wound healing.…”

Hydrogel scaffolds asin vitromodels to study fibroblast activation in wound healing and disease

“…53,54 The addition of HA alters the viscoelastic properties of collagen gels, but does not appear to affect the microstructure. 53 Reports on the effect of HA addition on fibroblast activation, proliferation, or cytoskeletal organization are somewhat varied, from reports of HA having no effect on fibroblast behavior to reports of HA increasing myofibroblast activity. 32,53,55 While it is generally accepted that HA contributes to wound healing via cell surface interactions and related signaling, it remains unclear whether or not HA affects wound healing or fibrosis via physical interactions.…”

The effects of hyaluronic acid hydrogels with tunable mechanical properties on neural progenitor cell differentiation

“…High molecular weight hyaluronic acid (HA) is an essential organizational and structural component in the ECM of native tissues [12][13][14]. HA is a linear-chain polysaccharide that has been shown to significantly influence wound healing [15], nerve regeneration [16,17], cell migration [18][19][20] and neuronal [12,20], as well as glial [21,22], development.…”