Meniscal material properties are minimally affected by matrix stabilization using glutaraldehyde and glycation with ribose

Abstract

Knee meniscus replacement holds promise, but current allografts are susceptible to biodegradation. Matrix stabilization with glutaraldehyde, a crosslinking agent used clinically to fabricate cardiovascular bioprostheses, or with glycation, a process of crosslinking collagen with sugars such as ribose, is a potential means of rendering tissue resistant to such degradation. However, stabilization should not significantly alter meniscal material properties, which could disturb normal function in the knee. Our objective was to evaluate the effects of glutaraldehyde-and glycation-induced matrix stabilization on the material properties of porcine meniscus.Normal untreated meniscus specimens were tested in confined compression at one of three applied stresses (0.069, 0.208, 0.347 MPa), subjected to either a glutaraldehyde or glycation stabilization treatment, and then re-tested to measure changes in tissue aggregate modulus, permeability, and compressive strain at equilibrium. Changes in these properties significantly increased with glutaraldehyde concentration and exposure time to ribose. One glutaraldehyde and three glycation treatments did not alter aggregate modulus or compressive strain at equilibrium compared to controls (p > 0.10). However, all treatments increased permeability by at least 108% compared to controls (p < 0.001). This study reveals a dose-dependent relationship between meniscal material properties and certain stabilization conditions and identifies treatments that minimally affect these properties. Further research is necessary to determine whether these treatments prevent enzymatic degradation before and after surgical implantation in the knee.

The influence of exogenous cross-linking and compressive creep loading on intradiscal pressure

“…It was concluded that differences in intradiscal pressure were not the result of differences in tissue hydration resulting from the minimal differences in bath osmolarity (less than 5%). The lack of excessive or non-uniform swelling was attributed to the integrity of the disc, presence of disc attachments to bone and endplate, and the increased hydraulic permeability generally associated with collagen cross-linking (Hunter et al 2005). It is also possible, though not measured in this study, that higher proteoglycan content in the treated tissue resulted in a relatively higher swelling pressure in the treated discs.…”

“…However a separate study documented a greater amount of fluid loss (>2×) from the nucleus of genipin cross-linked discs compared to PBSsoaked discs during 1 h of creep loading (Chuang et al 2009), and, as noted previously, the control discs did not have a significantly greater initial nucleus hydration than genipinsoaked discs. This greater amount of nuclear fluid loss in genipin cross-linked discs under sustained compressive loading suggests that the increase in hydraulic permeability due to cross-linking (Boyd-White and Williams 1996; Cochrane and Robinson 1995;Hunter et al 2005) dominated over a higher swelling pressure from cross-linking induced retention of proteoglycans. However it was unexpected that the increased outflow of fluid from the nucleus of cross-linked discs under compressive loading did not translate into greater depressurization, normalized for starting pressure, and a heightened divergence from control discs with regard to postcreep IDP response to load.…”

Beneficial Effects of Exogenous Crosslinking Agents on Self-Assembled Tissue Engineered Cartilage Construct Biomechanical Properties

“…For instance, Hunter et al 8 demonstrated up to a 2.8-fold higher aggregate modulus with 0.02% glutaraldehyde application to meniscal explants. Additionally, Chuang et al 13 found up to a 151% increase in “low compressive stiffness modulus” and a 78% increase in Young's modulus when applying 0.33% genipin to annulus fibrosus explants; however, it must be noted that genipin was applied for 48 h in this study, as opposed to the 3.5 h in our study.…”

“…For instance, glutaraldehyde has been widely used as a protein crosslinking agent for tissue fixation as well as stabilization, and has been successfully used to enhance the biomechanical properties of knee meniscus explants at low concentrations. 8 …”

“…9 Although the presence of AGEs is generally a sign of aging that is detrimental to diabetics, 10,11 glycation has been shown to be an interesting approach for enhancing tissue functional properties with minimal toxicity. 12 Based on a review of the literature, 8,12–16 ribose, genipin, and methylglyoxal were selected as glycation crosslinkers, and were compared to glutaraldehyde. Each of the four crosslinking agents was applied at a single concentration selected from the literature.…”