J. Patel (Decature, US)
Emory University OrthopaedicsPresenter Of 1 Presentation
P043 - Cartilage-Penetrating Hydrogel Mitigates Tissue Degeneration and Chondrocyte Catabolism
Abstract
Purpose
Cartilage injuries often result in progressive tissue degeneration, characterized by mechanical and biochemical loss. The purpose of this study was to determine the protective effects of a tissue-reinforcing hydrogel in slowing this deteriorative process.
Methods and Materials
Cartilage explants (bovine trochlea) were trimmed to remove the superficial and calcified zones to simulate defected tissue. Plugs were kept in basal (control) or degenerative media (10ng/mL IL-1β), with hydrogel application at 0 and 1 weeks (Fig 1A/B). Methacrylated hyaluronic acid (MeHA; 4% w/v) with LAP photo-initiator (0.05% w/v) was applied to the explant surface, allowed 5 minutes to diffuse, and photo-crosslinked for 3 minutes. Four conditions were tested: Control, IL-1, Reinforced (MeHA at t=1w) and Pre-Reinforced (MeHA at t=0w). At two weeks, a biphasic creep test was performed to obtain biphasic mechanical properties. Samples were then subject to s-GAG quantification (DMMB), staining for proteoglycan content (Safranin-O/Fast Green) and breakdown (NITEGE - aggrecan neoepitope), and measurement of catabolic gene expression (MMP-13).
Results
Cartilage fortification provided a protection of macroscale tissue mechanics in a degenerative culture (Fig 1C). s-GAG content of entire cartilage plugs showed no significant differences (Fig 1D). However, histological staining highlighted localized s-GAG depletion at the explant surface in degenerative media, while MeHA application led to enhanced s-GAG retention (Fig 2A/B). NITEGE exhibited a greater presence in the IL-1 group and mitigation in the MeHA-treated explants (Fig 2A/C). MMP-13 expression of IL-1 treated explants exhibited a 20+ fold increase, whereas reinforcement reduced these increases by more than half (Fig 2D).
Conclusion
Our MeHA hydrogel system, in a degenerative environment, provides protection from mechanical loss, improves s-GAG retention, and reduces matrix breakdown. This strategy could provide a simple yet effective treatment to halt the cartilage degenerative process. Future studies will explore these changes at the cellular level and translate this approach to an animal model.
Presenter Of 1 Presentation
P043 - Cartilage-Penetrating Hydrogel Mitigates Tissue Degeneration and Chondrocyte Catabolism
Abstract
Purpose
Cartilage injuries often result in progressive tissue degeneration, characterized by mechanical and biochemical loss. The purpose of this study was to determine the protective effects of a tissue-reinforcing hydrogel in slowing this deteriorative process.
Methods and Materials
Cartilage explants (bovine trochlea) were trimmed to remove the superficial and calcified zones to simulate defected tissue. Plugs were kept in basal (control) or degenerative media (10ng/mL IL-1β), with hydrogel application at 0 and 1 weeks (Fig 1A/B). Methacrylated hyaluronic acid (MeHA; 4% w/v) with LAP photo-initiator (0.05% w/v) was applied to the explant surface, allowed 5 minutes to diffuse, and photo-crosslinked for 3 minutes. Four conditions were tested: Control, IL-1, Reinforced (MeHA at t=1w) and Pre-Reinforced (MeHA at t=0w). At two weeks, a biphasic creep test was performed to obtain biphasic mechanical properties. Samples were then subject to s-GAG quantification (DMMB), staining for proteoglycan content (Safranin-O/Fast Green) and breakdown (NITEGE - aggrecan neoepitope), and measurement of catabolic gene expression (MMP-13).
Results
Cartilage fortification provided a protection of macroscale tissue mechanics in a degenerative culture (Fig 1C). s-GAG content of entire cartilage plugs showed no significant differences (Fig 1D). However, histological staining highlighted localized s-GAG depletion at the explant surface in degenerative media, while MeHA application led to enhanced s-GAG retention (Fig 2A/B). NITEGE exhibited a greater presence in the IL-1 group and mitigation in the MeHA-treated explants (Fig 2A/C). MMP-13 expression of IL-1 treated explants exhibited a 20+ fold increase, whereas reinforcement reduced these increases by more than half (Fig 2D).
Conclusion
Our MeHA hydrogel system, in a degenerative environment, provides protection from mechanical loss, improves s-GAG retention, and reduces matrix breakdown. This strategy could provide a simple yet effective treatment to halt the cartilage degenerative process. Future studies will explore these changes at the cellular level and translate this approach to an animal model.