Browsing by Subject "Tenocytes"

Now showing 1 - 4 of 4
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    Immunohistochemical and in situ hybridization observations favor a local catecholamine production in the human Achilles tendon
    (Murcia : F. Hernández, 2008) Bjur, Dennis; Danielson, Patrik; Alfredson, Hàkan; Forsgren, Sture
    Results of recent studies using immunohistochemistry show evidence of an occurrence of catecholamine production in the cells (tenocytes) of patellar tendons exhibiting tendinopathy (tendinosis). In the present study, antibodies against the catecholaminesynthesizing enzyme tyrosine hydroxylase (TH) and a1- adrenoreceptors were applied to sections of specimens of normal and tendinosis Achilles tendons. In situ hybridization using a probe detecting human TH mRNA was also utilized. It was found that sympathetic innervation was very scarce. On the other hand, there were distinct a1-adrenoreceptor immunoreactions in blood vessel walls. Interestingly, tenocytes, particularly from tendinosis samples in which the tenocytes showed an abnormal shape (not the typical slender appearance), displayed TH immunoreactions and reactions for TH mRNA. Of further interest was the finding of a1- adrenoreceptor immunoreactions in tenocytes. The observations show not only evidence of local catecholamine production at the protein level, which was the case in recent studies for the patellar tendon, but also at the mRNA level. The observations suggest that the tenocytes, especially those with disfigured appearances in tendinosis, can produce catecholamines and also that they can respond to sympathetic transmitters. This is of interest as adrenergic stimulation in other parts of the body is known to induce degenerative/apoptotic and proliferative events, features which are seen in Achilles tendinosis. These observations are completely new findings concerning the human Achilles tendon. It is likely that locally produced catecholamines and the occurrence of autocrine/paracrine effects of these substances are of great relevance during the process of tendinosis.
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    PRP and MSCs on tenocytes artificial wound healing: an in vitro study comparing fresh and frozen PRP
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Veronesi, Francesca; Pagani, Stefania; Torricelli, Paola; Filardo, Giuseppe; Cavallo, Carola; Grigolo, Brunella; Fini, Milena
    Tendon tissue has poor regenerative capacity due to its low vascularization, cell density and extracellular matrix (ECM) production. Therefore, tendon injuries are an increasing clinical problem because of the formation of scar tissue with traditional therapies. Regenerative medicine aims at triggering a healing response through the use of biological treatments such as mesenchymal stromal cells (MSCs) and growth factors (GFs). MSCs show several advantages in tendon clinical setting, while platelet rich plasma (PRP) has gained popularity because of its high GF concentration, although its applications in the tendon clinical setting are still controversial. The aim of the present study was to evaluate a combined treatment of MSCs and PRP in an in vitro microwound model of tendon injuries. In addition, fresh and frozen PRP were compared. Single human tenocytes cultures or co-cultures with bone marrow derived MSCs (BMSCs) were set up with or without human PRP, fresh or frozen. After 24 hours of culture, it was observed that MSCs alone significantly increased tenocyte migration speed, microwound healing rate, fibronectin, collagen I and aggrecan production. These effects were enhanced by the combination with PRP, fresh being more effective than frozen PRP. In addition, the number of MSCs and tenocytes inside the microwound was significantly increased, especially with fresh PRP. In conclusion, the combination of MSCs and PRP, especially the fresh one, increases tenocytes and MSC migration speed, as well as ECM protein production compared to the use of MSCs alone
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    Tendinopathy and its treatment with platelet-rich plasma (PRP)
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Jiang, Dapeng; Wang, James H-C.
    This article has two goals. First, it reviews studies on tendinopathy in the literature while highlighting the following points: a) tendinopathy refers to a spectrum of tendon disorders with multiple facets of "tissue phenotypes," and b) mechanical loading is a major factor that contributes to the development of tendinopathy by inducing the aberrant differentiation of tendon stem/progenitor cells into non-tenocyte cell lineages. Second, the current treatments of tendinopathy with platelet-rich plasma (PRP) are briefly described, issues related to PRP treatment in clinics are highlighted, and the needs for basic science research on clinical usage of PRP for tendinopathy treatment are discussed.
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    What understanding tendon cell differentiation can teach us about pathological tendon ossification
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Magne, D.; Bougault, C.
    Tendons are the structures that attach muscles to bones and transmit mechanical forces. Tendon cells are composed of mature tenocytes and a rare population of tendon stem cells. Both cell types ensure homeostasis and repair of tendon extracellular matrix to guarantee its specific mechanical properties. Moreover, tendon cells seem to present a marked potential for trans-differentiation, predominantly into the chondrocyte and osteoblast lineages. In this review article, we first present chronic tendon pathologies associated with abnormal ossification, such as spondyloarthritis and calcifying tendinopathy, and discuss how tendon cell differentiation and transdifferentiation may participate in these diseases. We moreover present the factors known to influence tendon cell differentiation and trans-differentiation, with a particular emphasis on extracellular environment, mechanical stimulation and several soluble factors that can tip the balance toward one or another lineage. A better understanding of the neglected tendon cell biology may be extremely useful to understand the pathological mechanisms of spondyloarthritis and calcifying tendinopathy.