In vitro glycation of articular cartilage alters the biomechanical response of chondrocytes in a depth-dependent manner

Abstract

In vitro glycation alters the biomechanical response of chondrocytes in cartilage differently in upper and deeper zones, offering possible insights into how aging could alter cell deformation behavior in cartilage.

Effect of collagen cross-linking on quantitative MRI parameters of articular cartilage

“…However, only 1% of the lysine modifications could be explained by CML and pentosidine in previous study 7 . The increase in FCD has also been previously reported with ribose treated bovine cartilage 11 , suggesting that these carbohydrates clearly have an effect on the charges in cartilage. However, to fully understand the process, further biochemical investigations with comprehensive amino acid analysis are required.…”

“…In mature tissue these are later replaced with more stable hydroxypyridinium cross-link species 8 such as hydroxylysyl pyridinoline (HP) and lysyl pyridinoline (LP) cross-links 9 . Previously, these characteristic age-related changes in cartilage have been investigated by artificial induction of cross-linking for example using ribose 10,11 or threose 12,13 . Threose is a highly reactive sugar, which has been shown to also form characteristic AGEs, such as pentosidine cross-links 7 .…”

Infrared microspectroscopic determination of collagen cross-links in articular cartilage

“…10 In a recent study, the ratio of the integrated absorbance of the carbohydrate region to the amide I absorbance was used to study the differences in AGEs between control and ribosetreated articular cartilage samples. 13 In the present study, the maximum correlation coefficient between the Pent concentration and the variables in the carbohydrate region was r ¼ 0.50. The samples in both groups of this study were similar in terms of the collagen and the proteoglycan contents, as the increased cross-linking was achieved by a threose treatment.…”

“…12 Recently, the same approach was used to study AGE components in articular cartilage. 13 However, the same parameter has also been used to assess the ratio of proteoglycan content to collagen content in articular cartilage.…”

Consequences of metabolic and oxidative modifications of cartilage tissue

“…85 However, the AGEs are likely to act over a very short period of time in vitro to mainly cross-link proteins, whereas the broader effects observed in vivo are probably mediated through a wider range of matrix protein modifications as well as altered to mechanosignals. 86 Indeed, prolonged oxidative stress reduces the synthesis of proteoglycan and collagen through effects that involve modulation of phosphatase and tensin homologue deleted on chromosome 10 (PTEN). PTEN functions as a negative regulator of phosphoinositol-3-kinase (PI3K)–AKT and ERK/MAPK signalling pathways, which instruct chondrocytes to upregulate matrix protein synthesis.…”