Comparison of Tenocyte Populations from the Core and Periphery of Equine Tendons

Abstract

Tendon is a highly organized, dense connective tissue that has been demonstrated to have very little turnover. In spite of the low turnover, tendon can grow in response to loading, which may take place primarily at the periphery. Tendon injuries and recurrence of injuries are common in both humans and animals in sports. It is unclear why some areas of the tendon are more susceptible to such injuries and whether this is due to intrinsic regional differences in extracellular matrix (ECM) production or tissue turnover. This study aimed to compare populations of tenocytes derived from the tendon core and periphery. Tenocytes were isolated from equine superficial digital flexor tendons (SDFTs), and the proliferation capacity was determined. ECM production was characterized by immuno-and histological staining and by liquid chromatography-mass spectrometry-based proteomics. Core and periphery SDFT cultures exhibited comparable proliferation rates and had very similar proteome profiles, but showed biological variation in collagen type I deposition. In conclusion, the intrinsic properties of tenocytes from different regions of the tendon are very similar, and other factors in the tissue may contribute to how specific areas respond to loading or injury.

Macromolecular crowding in human tenocyte and skin fibroblast cultures: A comparative analysis

“…Among the few matrisomal proteins enriched in hTCs, tendon related proteins (e.g. collagen types II and collagen type XIV [ 183 , 184 ], procollagen lysyl hydroxylase PLOD2 [ 185 , 186 ], growth factor TGFB2 [ 187 , 188 ]) and proteins with diverse functions (e.g. procoagulant protein FGL2 [ 189 ], protease CTSL [ 190 ], integrin-interacting protein EDIL3 [ 191 ]) were found.…”

“…procoagulant protein FGL2 [ 189 ], protease CTSL [ 190 ], integrin-interacting protein EDIL3 [ 191 ]) were found. Apart from the cell dissociation and repulsion receptors Plexin-C1 and -D1 [ 192 ] and the inhibitor of fibrinolysis SERPINB2 [ 193 ], the vast majority of the matrisome proteins enriched in hDFs have been previously identified in healthy tendons [ 137 , 138 , 183 , 186 , [194] , [195] , [196] ]. This provides an excellent explanation for the reported preclinical and clinical success of hDFs in tendon regeneration [ 19 , 20 , 70 , 197 , 198 ] and highlights the potential of hDFs in tendon engineering.…”

Achilles Tendons Display Region-Specific Transcriptomic Signatures Associated With Distinct Mechanical Properties

“…9 While the transcriptional profiles of whole tendons have been studied, less is known about the regional gene expression within a single tendon. Some studies have examined the region-specific expression of a small number of genes within tendons, 17,25,47 but a comprehensive atlas of spatial transcriptional differences has yet to be developed. Furthermore, mechanical properties of tendons are well characterized across the entire tendon, 6,31 but less is understood about the regional mechanical characteristics of Achilles tendons.…”

Tendon and multiomics: advantages, advances, and opportunities

“…Conversely, markers for peritenon were extended to include markers more typical of a vascularized tissue, collagen 15 alpha 1 ( Col15a1 ), integrin subunit alpha-4 ( Itga4 ), a disintegrin and metalloproteinase with thrombospondin motifs ( Adamts16 ), and a marker of endothelial and white blood cell lineages, fibrinogen like 2 ( Fgl2 ) 13 . In addition, an analysis of the core and periphery of equine tendons showed substantial overlap, but also nuances in ECM protein expression between different load-bearing regions of the same tendon 14 , although the peripheral tendon evaluated in this study also included some peritenon. Type IV collagen (COL4A2) was more abundant in cultures of the core tendon, whereas lysyl oxidase-like 2 (LOXL2), fibulin 5 (FBLN5), and a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) were more abundant in the periphery compared to the core.…”