Expression of cell adhesion molecule L1 in the long head of biceps tendon

K. Alpantaki, M. Savvaki, D. Karagogeos


Several studies have proposed that the nervous system participates in nociception and tendon healing process. The neural cell adhesion molecule L1 (L1-CAM), which has an important role in neural development and nociceptive pathways, has been described in the past in the skeletal muscles and tendino-muscular junction. The role of this protein in tendon pathology is unknown. Here, we show that L1-CAM is expressed in human tendons. Samples of the long head of the biceps tendon (LHB) from six patients undergoing shoulder surgery were studied. Both Western blot and immunofluorescence revealed a strong expression pattern of L1-CAM. These L1-CAM positive cells were also Tuj1 positive, suggesting a neuronal origin. To our knowledge this is the first unequivocal evidence of the presence of L1 CAM in human tendons suggesting that it may play a role in organization of extracellular matrix and tendon pain.


Tendon of long head of biceps, L1-CAM, shoulder pain, tendinosis.

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