By using ultramorphological and biochemical methods, we analyzed the regional differences between the three parts of the equine superficial digital flexor tendon (SDFT), namely, the myotendinous junction (MTJ), middle metacarpal (mM), and osteotendinous junction (OTJ). Cross-sectional images showed unique distributions of collagen fibrils of varying diameters in each region. Small collagen fibrils (diameter <100 nm) were distributed predominantly in the MTJ region, and the OTJ region was relatively rich in large collagen fibrils (diameter >200 nm). In the mM region, the collagen fibrils were intermediately distributed between the MTJ and OTJ. The results indicate a graded arrangement of collagen fibrils in the tendon. Type V collagen was detected preferentially in the MTJ region. Since type V collagen is believed to be one of the collagens regulating collagen fibril formation, its possible functionality in the MTJ region in terms of fibril formation and fibril arrangement in the tendon has been discussed here.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1080/03008200701692800 | DOI Listing |
iScience
January 2025
Abteilung Paläontologie, Bonner Institut für Organismische Biologie, Universität Bonn, 53115 Bonn, Germany.
Bone is formed by specialized cells whose activity allows bone to grow, change shape, and repair itself. Its composite structure of collagen fibrils and bioapatite nanocrystals gives bone exceptional mechanical strength. Using scanning electron microscopy, we show in fossil ichthyosaurs, 150 to 200 million years old, from the Jurassic of France and the UK, abundant and direct evidence of cellular activity on the fossilized forming, resting, and resorbing surfaces of bone trabeculae, as well as bone fibrils, Sharpey fibers, and cartilage fibers.
View Article and Find Full Text PDFElife
January 2025
Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
Collagen-I fibrillogenesis is crucial to health and development, where dysregulation is a hallmark of fibroproliferative diseases. Here, we show that collagen-I fibril assembly required a functional endocytic system that recycles collagen-I to assemble new fibrils. Endogenous collagen production was not required for fibrillogenesis if exogenous collagen was available, but the circadian-regulated vacuolar protein sorting (VPS) 33b and collagen-binding integrin α11 subunit were crucial to fibrillogenesis.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Organoid Research Center, Institute of Translational Medicine, Shanghai University, Shanghai 200444, People's Republic of China.
Osteoporosis (OP) is a systemic skeletal disorder characterized by decreased bone mineral density and a heightened risk of fractures. Therapies for OP have primarily focused on balancing bone formation and bone resorption, but enhancing the remineralization of osteoporotic bone is also a key strategy for effective repair. Recent insights into biomineralization mechanisms have highlighted the essential role of mineral-containing extracellular vesicles (EVs) secreted by osteoblasts in promoting bone marrow mesenchymal stromal/stem cell (BMSC) differentiation and initiating matrix mineralization.
View Article and Find Full Text PDFPeerJ
January 2025
University of Amsterdam, Amsterdam, Netherlands.
Background: Achilles tendinopathy (AT) management can be difficult, given the paucity of effective treatment options and the degenerative nature of the condition. Innovative therapies for Achilles tendinopathy are therefore direly needed. New therapeutic developments predominantly begin with preclinical animal and in vitro studies to understand the effects at the molecular level and to evaluate toxicity.
View Article and Find Full Text PDFMatrix Biol
February 2025
Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada. Electronic address:
Advanced Glycation End Products (AGEs) are the end result of the irreversible, non-enzymatic glycation of proteins by reducing sugars. These chemical modifications accumulate with age and have been associated with various age-related and diabetic complications. AGEs predominantly accumulate on proteins with slow turnover rates, of which collagen is a prime example.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!