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Abstract Tendons are collagen‐rich tissues that are necessary for movement and, as such, are exposed to mechanical forces. Mechanical loading impacts tendon formation, homeostasis and injury. Frequent injury and poor healing of tendon is a major clinical issue. An improved understanding of how tendon cells respond to mechanical forces is needed to advance new therapies to treat tendon injuries and limit degeneration caused by aberrant mechanical loading. In this review, we highlight recent discoveries in how mechanical stimulation impacts tendon and enthesis formation during development, as well as tendon maintenance and degradation during adulthood. We focus on understanding the cell‐level mechanotransduction mechanisms, which include calcium signalling, activation of specific cell receptors and ion channels, and the effect on primary cilia and other downstream cell signalling pathways. These recently identified mechanotransducers in tendon cells show promise as future therapeutic targets, which can be leveraged for tendon healing.image
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This content will become publicly available on April 8, 2026
Adipose stromal cells in the human rotator cuff are resistant to fibrotic microenvironmental cues
AbstractRotator cuff tears are the most common upper extremity orthopaedic injury, causing degenerative changes within the bone, tendon, joint capsule, bursa and muscle. These degenerative changes are linked to poor rehabilitative and surgical outcomes, which has launched investigations into co‐therapeutic biologics. Specifically, mesenchymal stem cells (MSCs) have shown promise in mitigating degenerative changes in animal models of rotator cuff tears, but reports of their impact on clinical outcomes remain mixed. Here we describe an alternative source of MSCs in the human shoulder, adipose stromal cells (ASCs) from the subacromial fat (SAF) pad. Compared to the gold‐standard subcutaneous (SQ) fat, we show that SAF ASCs are less sensitive to chemical and mechanical fibrotic cues, (1) retaining smaller cell area with reduced actin stress fibre alignment across a range of physiological and pathological stiffnesses, (2) having reduced traction forces and extracellular matrix production, and (3) having reduced myofibroblastic conversion in response to cytokine challenge. Furthermore, we show that SAF ASCs enhance fusion of primary human myoblasts via paracrine signalling. Despite a fibrotic signature in SAF from rotator cuffs with tendon tears, SAF ASCs sourced from torn rotator cuffs were equally effective at resisting fibroblastic conversion and promoting myogenesis as those from intact rotator cuffs, further supporting autologous clinical use of these cells. In conclusion, this study describes human SAF ASCs as an alternative, and potentially superior, cell source for rotator cuff therapies.image Key pointsAdipose tissue within the rotator cuff is a novel and understudied source of therapeutic adipose stromal cells.Here, we detail the impact rotator cuff tears have on adipose tissue within the shoulder, its resident adipose stromal cells, and make a comparison of shoulder adipose stromal cells to subcutaneous adipose stromal cells.Rotator cuff tears cause fibrosis of rotator cuff adipose tissue; this fibrosis does not impact downstream adipose stromal cell morphology or pro‐myogenic signaling.Rotator cuff adipose stromal cells resist fibrotic microenvironmental cues and have enhanced pro‐myogenic paracrine signaling compared with traditional subcutaneous adipose stromal cells.Rotator cuff adipose stromal cells represent a new cell type that can be impactful in advancing rotator cuff therapies.
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- Award ID(s):
- 2209684
- PAR ID:
- 10636842
- Publisher / Repository:
- THE JOURNAL OF PHYSIOLOGY
- Date Published:
- Journal Name:
- The Journal of Physiology
- ISSN:
- 0022-3751
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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