title: Evidence of sympathetic innervation and α1-adrenergic receptors of the long head of the biceps brachii tendon.
abstract: BACKGROUND
  The primary purpose of this study was to investigate the sympathetic innervation of the long head of the biceps brachii tendon LHB via immunohistochemical staining for protein S-100 and neuropeptide Y (NPY) in patients with complex proximal humerus fractures, in individuals with chronic biceps tendinosis in the setting of large rotator cuff tears (RC), and in cadaveric samples with no previously reported shoulder pathology.
  
  
  METHODS
  We investigated the presence of sympathetic innervation and α1-adrenergic receptors of the long head of the biceps brachii tendon (LHB) in patients with complex proximal humerus fractures and individuals with chronic biceps tendinosis in the setting of large rotator cuff tears (RC). The correlation of morphological features with immunohistochemical evidence of neural element presence was also investigated. Forty-one LHB tendon specimens were examined. Seventeen were harvested from patients who underwent hemiarthroplasty for proximal humerus fractures, 14 were from individuals with biceps tendinosis in the context of a large RC tear, and ten were from cadaveric controls with no previous shoulder pathology. Histologic examination was performed using hematoxylin and eosin. Immunohistochemistry was used to detect the expression of the protein S-100, neuropeptide Y, and α1-adrenergic receptors, as well as to characterize the potential neural differentiation of tendon cells.
  
  
  RESULTS
  A strong correlation between the expression of NPY/S-100, α1-adrenergic/S-100, and α1-adrenergic/NPY was found. The LHB tendon has sympathetic innervation and α1-adrenergic receptors in acute and chronic pathological conditions.
  
  
  CONCLUSIONS
  Our results provide useful guidance on the management of tendinosis and the handling of the LHB in hemiarthroplasties for fractures.
authors.affiliation: University Hospital of Heraklion, 1 Pindarou Str, 71305 Heraklion, Crete, Greece. ttosounidis@yahoo.com
authors.forename: Theodoros
authors.initials: T
authors.lastname: Tosounidis
authors.forename: Constantine
authors.initials: C
authors.lastname: Hadjileontis
authors.forename: Christos
authors.initials: C
authors.lastname: Triantafyllou
authors.forename: Varvara
authors.initials: V
authors.lastname: Sidiropoulou
authors.forename: Antonios
authors.initials: A
authors.lastname: Kafanas
authors.forename: George
authors.initials: G
authors.lastname: Kontakis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001178:Arthroplasty / Q000379:methods; D001706:Biopsy; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006810:Humeral Fractures / Q000601:surgery; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000378:metabolism; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D012044:Regression Analysis; D009418:S100 Proteins / Q000378:metabolism; D052256:Tendinopathy / Q000378:metabolism*; D013710:Tendons / Q000294:innervation*
chemical_list: D009478:Neuropeptide Y; D018340:Receptors, Adrenergic, alpha-1; D009418:S100 Proteins