Browsing by Subject "Achilles tendon"

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    In situ hybridization studies favouring the occurrence of a local production of BDNF in the human Achilles tendon
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2012) Bagge, Johan; Danielson, Patrik; Forsgren, Sture
    Brain derived neurotrophic factor (BDNF) is a multipotent neurotrophin known for its growth-influencing and apoptosis-modulating functions, as well as for its function to interact with neurotransmitters/neuromodulators. BDNF is reported to be mainly produced in the brain. BDNF can be absorbed into peripheral tissue from the blood stream. Expression of this neurotrophin at the protein level, as well as of the neurotrophin receptor p75, has been previously shown for the principal cells (tenocytes) of the Achilles tendon. However, there is no proof at the mRNA level that BDNF is produced by the tenocytes. As the Achilles tendon tenocytes show “neuronal-like” characteristics, in the form of expressions favouring synthesis of several neuromodulators/neurotransmitters, and as BDNF especially is produced in neurons, it is of interest to confirm this. In the present study, therefore, in situ hybridization for demonstration of BDNF mRNA was performed on biopsies from Achilles tendons of patients with tendinosis and pain-free non-tendinosis individuals. The results showed that the tenocytes of both groups exhibited BDNF mRNA reactions. These observations indeed favour the idea that BDNF is produced by tenocytes in the human Achilles tendon, why Achilles tendon tissue is a tissue in which BDNF can be locally produced. BDNF can have modulatory functions for the tenocytes, including apoptosis-modifying effects via actions on the p75 receptor and interactive effects with neurotransmitters/neuromodulators produced in these cells. This possibility should be further studied for Achilles tendon tissue
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    TenascinC and type I and III collagen expression in total Achilles tendon rupture. An immunohistochemical study
    (Murcia : F. Hernández, 2009) Pajala, Ari; Melkko, Jukka; Leppilahti, Juhana; Ohtonen, Pasi; Soini, Ylermi; Risteli, Juha
    Tendon tissue degeneration and changes in collagen composition play a role in spontaneous rupture of the human Achilles tendon. Tenascin-C has been shown to be present in the tissue pathology and changes in tissue loading. We made an immunohistological study of the expression of tenascin-C and type I and III collagens in ruptured human Achilles tendons. METHODS: Three tissue samples in ten individuals, one from the Achilles tendon rupture and two control samples from four and sixteen centimeters proximal in same tendon were collected at surgery. The specimen were fixed and labelled with specific antibodies to type I and III procollagens (PICP, PINP and PIIINP), mature type III collagen (IIINTP) and tenascin-C. The amount of reacting tissue was evaluated visually and graded on a semiquantitative scale. RESULTS: No difference in the expression of tenascin-C was found between the sites. Instead, mature type III collagen content (p=0.008) and type III collagen synthesis (p=0.016) were significantly increased at the rupture site relative to the control site 2. The amount of newly synthesized type I collagen (PINP, PICP) was relatively high at all sites, as expected. CONCLUSION: The expression of type III collagen is increased at the rupture site in the human Achilles tendon, but that of tenascin-C remains unchanged. This finding supports a tissue composition alteration background for Achilles tendon rupture, while the role of mechanical loading at the rupture site remains controversial.
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    The plantaris tendon in association with mid-portion Achilles tendinosis – Tendinosis-like morphological features and presence of a non-neuronal cholinergic system
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Spang, Christoph; Alfredson, Hàkan; Ferguson, Mark; Roos, Beverley; Bagge, Johan
    The plantaris tendon is often neglected in morphological/clinical studies on the lower extremity. There is, however, clinical evidence that the plantaris tendon is involved in cases with Achilles midportion tendinopathy/tendinosis. It is nevertheless unclear if the plantaris tendon exhibits tendinosis-like features in this situation. We therefore investigated the plantaris tendon of patients with midportion Achilles tendinosis when the plantaris tendon was found to be located very close to or invaginated into the Achilles tendon, a situation which very often has been found to be the case. There was a very large number of tenocytes in the tendon tissue and the tenocytes showed abnormal and irregular appearances, exhibiting widened/rounded and wavy appearances, and were frequently lined up in rows. These features are characteristic features in Achilles tendinosis tendons. The tendon cells showed a distinct immunoreaction for the acetylcholine (ACh) -producing enzyme choline acetyltransferase (ChAT). Frequent fibroblasts were found in the loose connective tissue and these cells also showed a marked ChAT immunoreaction. The study shows that the plantaris tendon is morphologically affected in a similar way to the Achilles tendon in cases with midportion Achilles tendinosis and medial pain. The plantaris tendon may accordingly be a co-factor in these cases. The results also favour that there is a local ACh production both within the tendon tissue of the plantaris tendon and in the loose connective tissue. In conclusion, it is evident that plantaris tendons lying invaginated into or very close to the Achilles tendon in cases with midportion Achilles tendinosis show similar tendinosis features as previously shown for the Achilles tendon itself in these cases.
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    Unexpected presence of the neurotrophins NGF and BDNF and the neurotrophin receptor p75 in the tendon cells of the human Achilles tendon
    (Murcia : F. Hernández, 2009) Bagge, Johan; Lorentzon, Ronny; Alfredson, Hàkan; Forsgren, Sture
    Neurotrophins are substances that have been shown to be important in growth and remodelling phases in different types of tissue. There is no information concerning the possible occurrences of neurotrophins and their receptors in tendons. In this study, sections of both chronic painful (tendinosis) and pain-free (nontendinosis) human Achilles tendons were immunohistochemically stained with antibodies against the neurotrophins NGF and BDNF, and their receptors TrkA, TrkB and p75. There were marked immunoreactions for NGF and BDNF in the tendon cells (tenocytes) of both tendinosis and non-tendinosis specimens. The tenocytes were also reactive for the receptor p75, but not for the receptors TrkA and TrkB. In addition, p75 immunoreactions were seen in nerve fascicles and in the walls of arterioles. This is the first study to identify neurotrophins in the tenocytes of human tendon. It is clear from this study that the local cells of tendons are sources of neurotrophins. The neurotrophins may play an important role in the tendon through their interaction with the receptor p75 in the tenocytes. These interactions may regulate tropic modulatory, and apoptotic effects. In conclusion, the observations show a new concept concerning production and function of neurotrophins, namely in the tenocytes of tendons.