Jeroen Degroot

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Our aim was to correlate the activity of matrix metalloproteinases (MMPs) with denaturation and the turnover of collagen in normal and pathological human tendons. MMPs were extracted from ruptured supraspinatus tendons (n=10), macroscopically normal ("control") supraspinatus tendons (n=29) and normal short head of biceps brachii tendons (n=24). Enzyme(More)
Advanced glycation end products (AGEs) accumulate with age and at an accelerated rate in diabetes. AGEs bind cell-surface receptors including the receptor for advanced glycation end products (RAGE). The dependence of RAGE binding on specific biochemical characteristics of AGEs is currently unknown. Using standardized procedures and a variety of AGE(More)
Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation(More)
We investigated whether plasma and synovial fluid (SF) samples from patients with rheumatoid arthritis (RA) contained extracellular mitochondrial DNA (mtDNA) or the oxidatively damaged DNA adduct 8-hydroxy-2'-deoxyguanosine (8-oxodG). Moreover, we correlated the laboratory findings of the patients with RA with their levels of mtDNA and 8-oxodG. SF and(More)
Synovial fluid potentially contains markers for early diagnosis and disease progression in degenerative joint diseases such as osteoarthritis. Here, a method is described for profiling endogenous peptides in human synovial fluid, using ultrafiltration, solid-phase extraction, nanoscale liquid chromatography, and high-resolution mass spectrometry. Synovial(More)
The hallmark of fibrotic processes is an excessive accumulation of collagen. The deposited collagen shows an increase in pyridinoline cross-links, which are derived from hydroxylated lysine residues within the telopeptides. This change in cross-linking is related to irreversible accumulation of collagen in fibrotic tissues. The increase in pyridinoline(More)
Fibrosis is characterized by an excessive accumulation of collagen which contains increased levels of pyridinoline cross-links. The occurrence of pyridinolines in the matrix is an important criterion in assessing the irreversibility of fibrosis, which suggests that collagen containing pyridinoline cross-links significantly contributes to the unwanted(More)
OBJECTIVE To examine the effect of nonenzymatic glycation of cartilage extracellular matrix on the synthetic activity of chondrocytes. METHODS The proteoglycan-synthesis rate (35SO4(2-) incorporation) and levels of advanced nonenzymatic glycation (determined by high-performance liquid chromatography measurement of pentosidine) were evaluated in human(More)
BACKGROUND Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. HYPOTHESIS In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. STUDY DESIGN Descriptive laboratory study. METHODS From 10 patients(More)
OBJECTIVE To analyse matrix metalloproteinases (MMPs) and tissue inhibitor-1 of MMPs (TIMP-1) levels in the systemic circulation and synovial fluid (SF) of patients with RA and to compare these levels with inflammatory and collagen degradation markers. METHODS ProMMP-1, -2, -3, -8, -9, TIMP-1, levels of MMP/alpha(2)-macroglobulin complexes, and collagen(More)