Variants within the COMP and THBS2 genes are not associated with Achilles tendinopathy in a case-control study of South African and Australian populations

Cartilage oligomeric matrix protein is a structural protein of the extracellular matrix, while thrombospondin-2 is a matricellular protein involved in cell–matrix interactions. Recent studies have shown that genetic variation is a significant risk factor for Achilles tendinopathy, and the genes encoding cartilage oligomeric matrix protein (COMP) and thrombospondin-2 (THBS2) were identified as good candidate genes for association with Achilles tendinopathy. This study aimed to test the association of sequence variants within these candidate genes with the risk of Achilles tendinopathy in participants from South Africa (SA) and Australia (AUS). Three-hundred and forty (133 SA; 207 AUS) control participants with no history of Achilles tendinopathy and 178 (94 SA; 84 AUS) participants clinically diagnosed with Achilles tendinopathy were genotyped for five single nucleotide polymorphisms within the COMP and THBS2 genes in this case-control study. There was no difference in genotype distributions between control and tendinopathy groups for either the THBS2 variants rs9505888, rs6422747 and rs9283850, or the COMP variants rs730079 and rs28494505 in the SA and AUS populations. As the selection of COMP and THBS2 as candidate genes was hypothesis driven, based on biological function, the possibility that other variants within these genes are associated with Achilles tendinopathy cannot be excluded.Web of Scienc

Recognition of Complete Muscle or Tendon Ruptures

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Ligament-Derived Matrix Stimulates a Ligamentous Phenotype in Human Adipose-Derived Stem Cells

Human adipose stem cells (hASCs) can differentiate into a variety of phenotypes. Native extracellular matrix (e.g., demineralized bone matrix or small intestinal submucosa) can influence the growth and differentiation of stem cells. The hypothesis of this study was that a novel ligament-derived matrix (LDM) would enhance expression of a ligamentous phenotype in hASCs compared to collagen gel alone. LDM prepared using phosphate-buffered saline or 0.1% peracetic acid was mixed with collagen gel (COL) and was evaluated for its ability to induce proliferation, differentiation, and extracellular matrix synthesis in hASCs over 28 days in culture at different seeding densities (0, 0.25 × 106, 1 × 106, or 2 × 106 hASC/mL). Biochemical and gene expression data were analyzed using analysis of variance. Fisher's least significant difference test was used to determine differences between treatments following analysis of variance. hASCs in either LDM or COL demonstrated changes in gene expression consistent with ligament development. hASCs cultured with LDM demonstrated more dsDNA content, sulfated-glycosaminoglycan accumulation, and type I and III collagen synthesis, and released more sulfated-glycosaminoglycan and collagen into the medium compared to hASCs in COL (p ≤ 0.05). Increased seeding density increased DNA content incrementally over 28 days in culture for LDM but not COL constructs (p ≤ 0.05). These findings suggest that LDM can stimulate a ligament phenotype by hASCs, and may provide a novel scaffold material for ligament engineering applications