Tendon cells receive mechanical signals from the load bearing matrices. The response to mechanical stimulation is crucial for tendon function. However, overloading tendon cells may deteriorate extracellular matrix integrity by activating intrinsic factors such as matrix metalloproteinases (MMPs) that trigger matrix destruction. We hypothesized that mechanical loading might induce interleukin-1beta (IL-1beta) in tendon cells, which can induce MMPs, and that extracellular ATP might inhibit the load-inducible gene expression. Human tendon cells isolated from flexor digitorum profundus tendons (FDPs) of four patients were made quiescent and treated with ATP (10 or 100 microM) for 5 min, then stretched equibiaxially (1 Hz, 3.5% elongation) for 2 h followed by an 18-h-rest period. Stretching induced IL-1beta, cyclooxygenase 2 (COX 2), and MMP-3 genes but not MMP-1. ATP reduced the load-inducible gene expression but had no effect alone. A medium change caused tendon cells to secrete ATP into the medium, as did exogenous UTP. The data demonstrate that mechanical loading induces ATP release in tendon cells and stimulates expression of IL-1beta, COX 2, and MMP-3. Load-induced endogenous IL-1beta may trigger matrix remodeling or a more destructive pathway(s) involving IL-1beta, COX 2, and MMP-3. Concomitant autocrine and paracrine release of ATP may serve as a negative feedback mechanism to limit activation of such an injurious pathway. Attenuation or failure of this negative feedback mechanism may result in the progression to tendinosis.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/jcb.10534 | DOI Listing |
Cureus
December 2024
Department of Anatomical Sciences, William Carey University College of Osteopathic Medicine, Hattiesburg, USA.
The digastric muscle is a suprahyoid muscle that is composed of an anterior belly and a posterior belly, which originate from the first and second pharyngeal arches, respectively, and they are innervated by the nerves of these arches. The digastric muscles are involved in the elevation of the hyoid bone and depression of the mandible during mastication, speech, and swallowing. In this report, we present the rare case of bilateral accessory anterior belly of the digastric muscles (ABDMs) that originated from the digastric fossa, medial to the anterior bellies.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangdong, PR China.
Inadequate tendon healing and heterotopic bone formation result in substantial pain and disability, yet the specific cells responsible for tendon healing remain uncertain. Here we identify a CD26 tendon stem/progenitor cells residing in peritendon, which constitutes a primitive stem cell population with self-renewal and multipotent differentiation potentials. CD26 tendon stem/progenitor cells migrate into the tendon midsubstance and differentiation into tenocytes during tendon healing, while ablation of these cells led to insufficient tendon healing.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Orthopedics, Beijing LongFu Hospital, Beijing, China.
Objective: We aimed to investigate the effects of Tongluo Zhitong formula on synovial fibroblast proliferation in human knee osteoarthritis (KOA).
Methods: Discarded synovial tissue collected from patients undergoing total knee arthroplasty at our hospital was digested with type I collagenase. Primary culture was performed on three to four generations of fibroblasts, which were treated with high, medium, and low concentrations of Tongluo Zhitong formula.
BMC Musculoskelet Disord
January 2025
Department of Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA.
Background: Rotator cuff repairs may fail because of compromised blood supply, suture anchor pullout, or poor fixation to bone. To augment the repairs and promote healing of the tears, orthobiologics, such a platelet-rich plasma (PRP), and biologic scaffolds have been applied with mixed results. Adipose allograft matrix (AAM), which recruits native cells to damaged tissues, may also be a potential treatment for rotator cuff tears.
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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!