Characterization of and host response to tyramine substituted-hyaluronan enriched fascia extracellular matrix

Abstract

Naturally-occurring biomaterial scaffolds derived from extracellular matrix (ECM) have been previously investigated for soft tissue repair. We propose to enrich fascia ECM with high molecular weight tyramine substituted-hyaluronan (TS-HA) to modulate inflammation associated with implantation and enhance fibroblast infiltration. As critical determinants of constructive remodeling, the host inflammatory response and macrophage polarization to TS-HA enriched fascia were characterized in a rat abdominal wall model. TS-HA treated fascia with cross-linking had a similar lymphocyte (P = 0.11) and plasma cell (P = 0.13) densities, greater macrophage (P = 0.001) and giant cell (P < 0.0001) densities, and a lower density of fibroblast-like cells (P < 0.0001) than water treated controls. Treated fascia, with or without cross-linking, exhibited a predominantly M2 pro-remodeling macrophage profile similar to water controls (P = 0.82), which is suggestive of constructive tissue remodeling. Our findings demonstrated that HA augmentation can alter the host response to an ECM, but the appropriate concentration and molecular weight needed to minimize chronic inflammation within the scaffold remains to be determined.

Human fascia lata ECM scaffold augmented with immobilized hyaluronan: inflammatory response and remodeling in the canine body wall and shoulder implantation sites

“…[14] Specifically, fascia patches were rehydrated in ~2 ml of 0.19% low MW THA (57 kDa, Lifecore Biomedical, Chaska, MN)in ultrapure water containing 10 U/ml of horseradish peroxidase (Sigma, St. Louis, MO)for 24 h at 37 °C on a shaker. For each sample, all treatment steps were performed in the minimum volume necessary to fully rehydrate the sample.…”

“…Eighteen water- and THA-treated samples were reserved for implantation, and the remaining 12 samples in each group were used to verify with fluorophore-assisted carbohydrate electrophoresis [20] that HA content in the fascia reached our intended level of ~7.5 μg/mg. [14] Indeed, the HA content in THA-treated fascia averaged 7.3 ±1.7 μg/mg tissue weight and in water-treated control implants averaged 1.7 ±0.6 μg/ mg tissue weight. To facilitate surgical fixation of the implants, a non-resorbable 2–0 polypropylene fiber (Proxy Biomedical Ltd, Galway, Ireland) was stitched into each sample in a U-shaped pattern, leaving 8 cm free lengths of fiber extending from one end for fixation (Figure 1(A)).…”

“…Hence, we initially immobilized high molecular weight (MW) THA (0.9–1 MDa) into fascia lata ECM at an average concentration of 7.6 μg/mg tissue and investigated inflammatory response in a rat body wall model. [14] In this case, HA augmentation resulted an undesirable increase in macrophage and giant cell densities, and a lower density of fibroblast-like cells than in water-treated controls,[14] and was characterized by persistent and prominent localizations of THA hydrogel within the fascia ECM matrix. [14] As such, the motivation for the current study was to incorporate low MW THA into fascia ECM to facilitate more uniform diffusion throughout the dense matrix prior to crosslinking, potentially eliminating the prominent localizations of THA and facilitating an anti-inflammatory role for it.…”

“…[14] Fascia grafts will be implanted at both body wall and shoulder injury sites in the canine model, and the inflammatory response and graft remodeling will be evaluated at 12 weeks. We hypothesize that the immobilization of low MW THA in fascia ECM will reduce the inflammatory cell infiltrate and decrease graft remodeling as compared to water-treated fascia.…”

Chondrocyte Cultivation in Hyaluronan-Tyramine Cross-Linked Hydrogel

“…The cross-linking reaction is triggered by horseradish peroxidase and hydrogen peroxide and may proceed under mild conditions that are not harmful for many types of cells and enable their long-term survival. Moreover, results suggest that this hydrogel is not toxic and does not provoke an immune reaction when injected subcutaneously [9][10][11].…”