Key Points: Angiopoietin-like 4 (ANGPTL4) modulates tendon neovascularization. Cyclic loading stimulates the activity of transforming growth factor-β and hypoxia-inducible factor 1α and thereby increases the expression and release of ANGPTL4 from human tendon cells. Targeting ANGPTL4 and its regulatory pathways is a potential avenue for regulating tendon vascularization to improve tendon healing or adaptation.
Abstract: The mechanisms that regulate angiogenic activity in injured or mechanically loaded tendons are poorly understood. The present study examined the potential role of angiopoietin-like 4 (ANGPTL4) in the angiogenic response of tendons subjected to repetitive mechanical loading or injury. Cyclic stretching of human tendon fibroblasts stimulated the expression and release of ANGPTL4 protein via transforming growth factor-β (TGF-β) and hypoxia-inducible factor 1α (HIF-1α) signalling, and the released ANGPTL4 was pro-angiogenic. Angiogenic activity was increased following ANGPTL4 injection into mouse patellar tendons, whereas the patellar tendons of ANGPTL4 knockout mice displayed reduced angiogenesis following injury. In human rotator cuff tendons, the expression of ANGPTL4 was correlated with the density of tendon endothelial cells. To our knowledge, this is the first study characterizing a role of ANGPTL4 in the tendon. ANGPTL4 may assist in the regulation of vascularity in the injured or mechanically loaded tendon. TGF-β and HIF-1α comprise two signalling pathways that modulate the expression of ANGPTL4 by mechanically stimulated tendon fibroblasts and, in the future, these could be manipulated to influence tendon healing or adaptation.
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http://dx.doi.org/10.1113/JP271752 | DOI Listing |
Front Med (Lausanne)
December 2024
Rheumatology Unit, Department of Medicine-DIMED, University - Padova University Hospital, Padua, Italy.
Objectives: This pilot study aimed to identify early predictors of drug retention in patients with clinically active peripheral psoriatic arthritis who initiated or switched to therapy with biologic and targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs).
Methods: Clinical and ultrasound assessments were conducted at baseline (t0) and subsequently at 1 (t1), 3 (t3), and 6 (t6) months. Ultrasound evaluations targeted joints/entheses according to PsASon-Score13 and the most clinically involved joint/enthesis/tendon or the two most clinically involved joints/entheses/tendons (MIJET and 2MIJET).
Rheumatol Adv Pract
December 2024
Department of Anesthesiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
Objectives: Rotator cuff tendinitis (RCT) is a tendon inflammation often following subacromial impingement syndrome. One of the non-surgical management modalities for RCT is subacromial injection of corticosteroids. Some studies have claimed a correlation between ACTH (Adrenocorticotropic Hormone) deficiency and rotator cuff lesions; hence, intramuscular ACTH analogue injection has been recommended as an option.
View Article and Find Full Text PDFTendinopathy is an age-associated degenerative disease characterized by a loss in extracellular matrix (ECM). Since glucose and glutamine metabolism is critical to amino acid synthesis and known to be altered in aging, we sought to investigate if age-related changes in metabolism are linked to changes in ECM remodeling. We exposed young and aged tendon explants to various concentrations of glucose and glutamine to observe changes in metabolic processing (enzyme levels, gene expression, etc.
View Article and Find Full Text PDFOrthop J Sports Med
January 2025
Department of Orthopaedics & Traumatology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR.
Background: The incidence of anterior cruciate ligament reconstruction (ACLR) graft failure is inversely related to the diameter of the ACLR graft. When the diameter of a 4-stranded hamstring tendon graft with a doubled semitendinosus and doubled gracilis tendon (ST×2 + G×2) configuration is <8 mm, the gracilis tendon is often thin.
Hypothesis: (1) The diameter of the doubled semitendinosus tendon (ST×2) alone would be able to predict the probability of a 4-stranded ACLR graft having a diameter of ≥8 mm, and (2) there would be a specific cutoff value for the ST×2 diameter such that the addition of a doubled gracilis tendon (G×2) will not result in a 4-stranded graft with a ≥8-mm diameter.
Orthop J Sports Med
January 2025
Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Background: The Simple Shoulder Test (SST) is a widely used patient-reported outcome measure for shoulder function. However, there is currently no version of the SST for the Thai population.
Purpose: To cross-culturally adapt and evaluate the reliability and validity of a Thai version of the SST (Thai SST) for patients with shoulder pathologies, using the Thai version of the American Shoulder and Elbow Surgeons (ASES) score as a comparison tool.
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