title: Apoptosis occurs throughout the diseased rotator cuff.
abstract: BACKGROUND
  Even though apoptosis is known to be closely associated with rotator cuff tears, the differences in apoptosis according to the location within the torn supraspinatus tendon are still unknown.
  
  
  OBJECTIVE
  To elucidate where apoptosis begins within the supraspinatus tendon.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Tendon tissues were collected from 14 patients undergoing arthroscopic rotator cuff repair surgery and 7 patients undergoing surgery for proximal humeral fracture who served as controls. In the patients with rotator cuff tears, the samples were harvested at 3 sites: the most lateral torn margin, 1 cm medial from the torn margin, and at the posterior torn corner. Caspase 3/7, 8, and 9 and cytochrome c activities were measured to determine the intracellular apoptosis pathway. Apoptotic cells were determined by in situ TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining, and immunohistochemistry was performed.
  
  
  RESULTS
  The apoptotic activities of tendons from the experimental subjects were significantly higher than those of the controls. There were, however, no significant differences between the 3 sample sites. Immunohistochemistry also revealed strong expression of increased caspase 3/7, 8, and 9 and cytochrome c but no significant difference between them.
  
  
  CONCLUSIONS
  This study shows that the intracellular apoptotic pathway is not only through the cell membrane receptor but also via intracellular mitochondria cascade.
  
  
  CONCLUSIONS
  Because apoptosis occurs regardless of the location within the rotator cuff, debridement of the torn margin to obtain a healthy tendon may not be needed. Further study should focus on not only the technique of tying the torn tendon back to the bone but also biological augmentation to reverse or prevent further apoptosis within rotator cuff tendon.
authors.affiliation: Yang-Soo Kim, Department of Orthopedic Surgery, Seoul St Mary's Hospital, the Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul, Korea, 137-701. kysoos@catholic.ac.kr.
authors.forename: Hyo-Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Yang-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Ok
authors.forename: Ha-Jung
authors.initials: HJ
authors.lastname: Song
mesh_terms: D000368:Aged; D017209:Apoptosis; D016022:Case-Control Studies; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008875:Middle Aged; D017006:Rotator Cuff / Q000201:enzymology / Q000473:pathology; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000201:enzymology / Q000209:etiology / Q000473:pathology*
chemical_list: D045304:Cytochromes c; D020169:Caspases
keywords: apoptosis; caspase; cytochrome c; rotator cuff disease; spatial distribution