Understanding adaption to load is essential for prevention and treatment of tendinopathy/tendinosis. Cytokine release in response to load is one mechanism involved in mechanotransduction. The cytokine tumor necrosis factor alpha (TNF-α) is implicated in tendinosis and can induce apoptotic effects via tumor necrosis factor receptor 1 (TNFR1). The complete absence of information concerning the TNF-α system in Achilles tendon is a limitation as mid-portion Achilles tendinosis is very frequent. Purpose: To examine expression patterns of TNF-α and its two receptors (TNFR1 and TNFR2) in human Achilles tendinosis and control tissue and to biochemically confirm the presence of TNF-α in tendinosis tissue. Methods: TNF-α and TNFR1 mRNA were detected via in situ hybridization. TNF-α, TNFR1, and TNFR2 were demonstrated immunohistochemically. Apoptosis markers were utilized. ELISA was used to detect TNF-α. Results: TNF-α and TNFR1 mRNA was detected in tenocytes of both tendinosis and control tendons. Tenocytes from both groups displayed specific immunoreactions for TNF-α, TNFR1, and TNFR2. The widened/rounded tenocytes of tendinosis samples exhibited the most intense immunoreactions. Apoptosis was detected in only a subpopulation of the tenocytes in tendinosis tissue. TNF-α was measurable in tendinosis tissue. Inflammatory cells were not seen. Conclusion: This is the first evidence of the existence of the TNF-α system in the human Achilles tendon. Findings are confirmed at mRNA and protein levels as well as biochemically. The TNF-α system was in principle confined to the tenocytes. The connection between tenocyte morphology and the expression pattern of TNF-α, TNFR1, and TNFR2 suggests that the TNF-α system may be involved in tenocyte activation in Achilles tendinosis.

Abraham, T., G. Fong, A. Scott (2011) Second harmonic generation analysis of early Achilles tendinosis in response to in vivo mechanical loading. BMC Musculoskelet Disord 12: 26.
Alfredson, H. (2005) The chronic painful Achilles and patellar tendon: research on basic biology and treatment. Scand J Med Sci Sports 15: 252–259.
Alfredson, H., D. Bjur, K. Thorsen, R. Lorentzon, P. Sandström (2002) High intratendinous lactate levels in painful chronic Achilles tendinosis: an investigation using microdialysis technique. J Orthop Res 20: 934–938.
Amini-Shirazi, N., A. Hoseini, A. Ranjbar, A. Mohammadirad, P. Khoshakhlagh, N. Yasa, M. Abdollahi (2009) Inhibition of tumor necrosis factor and nitrosative/oxidative stresses by Ziziphora clinopoides (Kahlioti); a molecular mechanism of protection against dextran sodium sulfate-induced colitis in mice. Toxicol Mech Methods 19: 183–189.
Åström, M., A. Rausing (1995) Chronic Achilles tendinopathy: a survey of surgical and histopathologic findings. Clin Orthop Relat Res 316: 151–164.
Bjur, D., P. Danielson, H. Alfredson, S. Forsgren (2008) Immunohistochemical and in situ hybridization observations favor a local catecholamine production in the human Achilles tendon. Histol Histopathol 23: 197–208.
Chiquet, M., L. Gelman, R. Lutz, S. Maier (2009) From mechanotransduction to extracellular matrix gene expression in fibroblasts. Biochim Biophys Acta 1793: 911–920.
Clancy, W.G. (1990) Tendon trauma and overuse injuries; in Leadbetter, W.B., J.A. Buckwalter, S.L. Gordon (eds): Sports-Induced Inflammation: Clinical and Basic Science Concepts. Park Ridge, American Academy of Orthopaedic Surgeons, pp 609–618.
Cook, J.L., J.A. Feller, S.F. Bonar, K.M. Khan (2004) Abnormal tenocyte morphology is more prevalent than collagen disruption in asymptomatic athletes’ patellar tendons. J Orthop Res 22: 334–338.
Danielson, P., H. Alfredson, S. Forsgren (2007) In situ hybridization studies confirming recent findings of the existence of a local nonneuronal catecholamine production in human patellar tendinosis. Microsc Res Tech 70: 908–911.
de Mos, M., L.A. Joosten, B. Oppers-Walgreen, J.T. van Schie, H. Jahr, G.J. van Osch, J.A. Verhaar (2009) Tendon degeneration is not mediated by regulation of Toll-like receptors 2 and 4 in human tenocytes. J Orthop Res 27: 1043–1047.
Fedorczyk, J.M., A.E. Barr, S. Rani, H.G. Gao, M. Amin, S. Amin, J. Litvin, M.F. Barbe (2010) Exposure-dependent increases in IL-1beta, substance P, CTGF, and tendinosis in flexor digitorum tendons with upper extremity repetitive strain injury. J Orthop Res 28: 298–307.
Fischer, R., O. Maier, M. Naumer, A. Krippner-Heidenreich, P. Scheurich, K. Pfizenmaier (2011) Ligand-induced internalization of TNF receptor 2 mediated by a di-leucin motif is dispensable for activation of the NFkappaB pathway. Cell Signal 23: 161–170.
Fung, D.T., J.B. Sereysky, J. Basta-Pljakic, D.M. Laudier, R. Huq, K.J. Jepsen, M.B. Schaffler, E.L. Flatow (2010) Second harmonic generation imaging and Fourier transform spectral analysis reveal damage in fatigue-loaded tendons. Ann Biomed Eng 38: 1741–1751.
Grasl-Kraupp, B., B. Ruttkay-Nedecky, H. Koudelka, K. Bukowska, W. Bursch, R. Schulte-Hermann (1995) In situ detection of fragmented DNA (TUNEL assay) fails to discriminate among apoptosis, necrosis, and autolytic cell death: a cautionary note. Hepatology 21: 1465–1468.
Grell, M., E. Douni, H. Wajant, M. Lohden, M. Clauss, B. Maxeiner, S. Georgopoulos, W. Lesslauer, G. Kollias, K. Pfizenmaier, P. Scheurich (1995) The transmembrane form of tumor necrosis factor is the prime activating ligand of the 80 kDa tumor necrosis factor receptor. Cell 83: 793–802.
Hansson, M., S. Forsgren (1995) Immunoreactive atrial and brain natriuretic peptides are co-localized in Purkinje fibres but not in the innervation of the bovine heart conduction system. Histochem J 27: 222–230.
Hosaka, Y., R. Kirisawa, H. Ueda, M. Yamaguchi, K. Takehana (2005) Differences in tumor necrosis factor (TNF)alpha and TNF receptor-1-mediated intracellular signaling factors in normal, inflamed and scar-formed horse tendons. J Vet Med Sci 67: 985–991.
Hosaka, Y., S. Ozoe, R. Kirisawa, H. Ueda, K. Takehana, M. Yamaguchi (2006) Effect of heat on synthesis of gelatinases and pro-inflammatory cytokines in equine tendinocytes. Biomed Res 27: 233–241.
Hosaka, Y., Y. Sakamoto, R. Kirisawa, T. Watanabe, H. Ueda, K. Takehana, M. Yamaguchi (2004) Distribution of TNF receptors and TNF receptor-associated intracellular signaling factors on equine tendinocytes in vitro. Jpn J Vet Res 52: 135–144.
Ihnatko, R., M. Kubes (2007) TNF signaling: early events and phosphorylation. Gen Physiol Biophys 26: 159–167.
Inoue, J., T. Ishida, N. Tsukamoto, N. Kobayashi, A. Naito, S. Azuma, T. Yamamoto (2000) Tumor necrosis factor receptor-associated factor (TRAF) family: adapter proteins that mediate cytokine signaling. Exp Cell Res 254: 14–24.
John, T., D. Lodka, B. Kohl, W. Ertel, J. Jammrath, C. Conrad, C. Stoll, C. Busch, G. Schulze-Tanzil (2010) Effect of pro-inflammatory and immunoregulatory cytokines on human tenocytes. J Orthop Res 28: 1071–1077.
Khan, K.M., J.L. Cook, F. Bonar, P. Harcourt, M. Astrom (1999) Histopathology of common tendinopathies: update and implications for clinical management. Sports Med 27: 393–408.
Kujala, U.M., S. Sarna, J. Kaprio (2005) Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes. Clin J Sport Med 15: 133–135.
Landis, J.R., G.G. Koch (1977) The measurement of observer agreement for categorical data. Biometrics 33: 159–174.
Lian, Ø., A. Scott, L. Engebretsen, R. Bahr, V. Duronio, K. Khan (2007) Excessive apoptosis in patellar tendinopathy in athletes. Am J Sports Med 35: 605–611.
Lin, T.W., L. Cardenas, D.L. Glaser, L.J. Soslowsky (2006) Tendon healing in interleukin-4 and interleukin-6 knockout mice. J Biomech 39: 61–69.
Luo, D., Y. Luo, Y. He, H. Zhang, R. Zhang, X. Li, W.L. Dobrucki, A.J. Sinusas, W.C. Sessa, W. Min (2006) Differential functions of tumor necrosis factor receptor 1 and 2 signaling in ischemia-mediated arteriogenesis and angiogenesis. Am J Pathol 169: 1886–1898.
Machner, A., A. Baier, A. Wille, S. Drynda, G. Pap, A. Drynda, C. Mawrin, F. Buhling, S. Gay, W. Neumann, T. Pap (2003) Higher susceptibility to Fas ligand induced apoptosis and altered modulation of cell death by tumor necrosis factor-alpha in periarticular tenocytes from patients with knee joint osteoarthritis. Arthritis Res Ther 5: R253–R261.
Maddahi, A., L.S. Kruse, Q.W. Chen, L. Edvinsson (2011) The role of tumor necrosis factor-alpha and TNF-alpha receptors in cerebral arteries following cerebral ischemia in rat. J Neuroinflammation 8: 107.
Maffulli, N., V. Testa, G. Capasso, S.W. Ewen, A. Sullo, F. Benazzo, J.B. King (2004) Similar histopathological picture in males with Achilles and patellar tendinopathy. Med Sci Sports Exerc 36: 1470–1475.
Millar, N.L., A.Q. Wei, T.J. Molloy, F. Bonar, G.A. Murrell (2009) Cytokines and apoptosis in supraspinatus tendinopathy. J Bone Joint Surg Br 91: 417–424.
Movin, T., A. Gad, F.P. Reinholt, C. Rolf (1997) Tendon pathology in long-standing achillodynia: biopsy findings in 40 patients. Acta Orthop Scand 68: 170–175.
Pan, H., J. Halper (2003) Regulation of heat shock protein 47 and type I procollagen expression in avian tendon cells. Cell Tissue Res 311: 373–382.
Panoskaltsis-Mortari, A., R.P. Bucy (1995) In situ hybridization with digoxigenin-labeled RNA probes: facts and artifacts. Biotechniques 18: 300–307.
Posthumus, M., M. Collins, J. Cook, C.J. Handley, W.J. Ribbans, R.K. Smith, M.P. Schwellnus, S.M. Raleigh (2010) Components of the transforming growth factor-beta family and the pathogenesis of human Achilles tendon pathology – a genetic association study. Rheumatology 49: 2090–2097.
Roux, C.H., F. Guillemin, S. Boini, F. Longuetaud, N. Arnault, S. Hercberg, S. Briancon (2005) Impact of musculoskeletal disorders on quality of life: an inception cohort study. Ann Rheum Dis 64: 606–611.
Schulze-Tanzil, G., O. Al-Sadi, E. Wiegand, W. Ertel, C. Busch, B. Kohl, T. Pufe (2011) The role of pro-inflammatory and immunoregulatory cytokines in tendon healing and rupture: new insights. Scand J Med Sci Sports 21: 337–351.
Scott, A., J.L. Cook, D.A. Hart, D.C. Walker, V. Duronio, K.M. Khan (2007) Tenocyte responses to mechanical loading in vivo: a role for local insulin-like growth factor 1 signaling in early tendinosis in rats. Arthritis Rheum 56: 871–881.
Siripin, D., S. Fucharoen, D.I. Tanyong (2011) Nitric oxide and caspase 3 mediated cytokine induced apoptosis in acute leukemia. Asian Pac J Allergy Immunol 29: 102–111.
Skutek, M., M. van Griensven, J. Zeichen, N. Brauer, U. Bosch (2001) Cyclic mechanical stretching enhances secretion of interleukin 6 in human tendon fibroblasts. Knee Surg Sports Traumatol Arthrosc 9: 322–326.
Sun, H.B., Y. Li, D.T. Fung, R.J. Majeska, M.B. Schaffler, E.L. Flatow (2008) Coordinate regulation of IL-1beta and MMP-13 in rat tendons following subrupture fatigue damage. Clin Orthop Relat Res 466: 1555–1561.
Uchida, H., H. Tohyama, K. Nagashima, Y. Ohba, H. Matsumoto, Y. Toyama, K. Yasuda (2005) Stress deprivation simultaneously induces over-expression of interleukin-1beta, tumor necrosis factor-alpha, and transforming growth factor-beta in fibroblasts and mechanical deterioration of the tissue in the patellar tendon. J Biomech 38: 791–798.
Unglaub, F., M.B. Wolf, A. Dragu, R.E. Horch (2010) Molecular events of cellular apoptosis and proliferation in the early tendon healing period. J Hand Surg Am 35: 691–692, author reply 692–693.
Vanden Berghe, T., G. Denecker, G. Brouckaert, D. Vadimovisch Krysko, K. D’Herde, P. Vandenabeele (2004) More than one way to die: methods to determine TNF-induced apoptosis and necrosis. Methods Mol Med 98: 101–126.
Waggett, A.D., M. Benjamin, J.R. Ralphs (2006) Connexin 32 and 43 gap junctions differentially modulate tenocyte response to cyclic mechanical load. Eur J Cell Biol 85: 1145–1154.
Wang, B.W., H. Chang, S. Lin, P. Kuan, K.G. Shyu (2003) Induction of matrix metalloproteinases-14 and -2 by cyclical mechanical stretch is mediated by tumor necrosis factor-alpha in cultured human umbilical vein endothelial cells. Cardiovasc Res 59: 460–469.
Webster, D.F., H.C. Burry (1982) The effects of hypoxia on human skin, lung and tendon cells in vitro. Br J Exp Pathol 63: 50–55.
Yang, J.H., W.H. Briggs, P. Libby, R.T. Lee (1998) Small mechanical strains selectively suppress matrix metalloproteinase-1 expression by human vascular smooth muscle cells. J Biol Chem 273: 6550–6555.
Yokoyama, T., K. Sekiguchi, T. Tanaka, K. Tomaru, M. Arai, T. Suzuki, R. Nagai (1999) Angiotensin II and mechanical stretch induce production of tumor necrosis factor in cardiac fibroblasts. Am J Physiol 276: H1968–H1976.
Zhan, M., B. Jin, S.E. Chen, J.M. Reecy, Y.P. Li (2007) TACE release of TNF-alpha mediates mechanotransduction-induced activation of p38 MAPK and myogenesis. J Cell Sci 120: 692–701.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.