title: Is resection of the tendon edge necessary to enhance the healing process? An evaluation of the expression of collagen type I, IL-1β, IFN-γ, IL-4, and IL-13 in the distal 1 cm of a torn supraspinatus tendon: part II.
abstract: BACKGROUND
  Type I collagen proin pro-in expression in a damaged supraspinatus tendon is thought to be dependent on the distance from the edge of the tear and the local expression of pro-inflammatory, anti-proliferative, and pro-proliferative cytokines. The study evaluates the expression of type I collagen, pro-inflammatory interleukin (IL) 1β, anti-proliferative interferon-γ (IFN-γ), and pro-proliferative IL-4 and IL-13 cytokines along a 1-cm section taken from the edge of a torn supraspinatus tendon. Three sections were taken: 3 mm distal to the tear, 3 mm proximal to the tear, and the 4-mm middle section between them.
  
  
  METHODS
  Nine patients (average age, 58 years) were included in the study. All fulfilled strict inclusion criteria regarding tear morphology and reconstruction technique. Samples were taken from the ruptured supraspinatus tendon at the time of arthroscopic repair. Quantitative real-time polymerase chain reaction assay was used for analysis.
  
  
  RESULTS
  The expression of type I collagen, IL-4, and IL-13 significantly increased and that of IL-1β and IFN-γ decreased from the distal to the proximal parts of the tendon edge (P < .05).
  
  
  CONCLUSIONS
  The expression of type I collagen is dependent on the distance from the edge of the torn supraspinatus tendon, the balance between anti-proliferative IFN-γ and pro-proliferative IL-4 and IL-13, and the expression of pro-inflammatory IL-1β. Hence, whereas resection of the distal 3 mm of the torn supraspinatus tendon edge eliminates its least valuable part, resection between 4 and 7 mm may enhance the healing process by reaching a reasonable compromise between the mechanical features of the tendon characterized by collagen type I expression and the technical abilities of reconstruction.
authors.affiliation: Department of Arthroscopy, Minimally Invasive Surgery and Sports Traumatology, Medical University of Łódź, Poland; FMC Private Medical Centre Łódź, Poland. Electronic address: fabis@onet.eu.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Fabiś
authors.affiliation: Department of Medical Biochemistry, Medical University of Łódź, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Szemraj
authors.affiliation: Department of Nucleic Acids Biochemistry, Medical University of Łódź, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Strek
authors.affiliation: Polish Mother's Memorial Research Institute, Łódź, Poland; FMC Private Medical Centre Łódź, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Fabiś
authors.affiliation: Department of Hand Surgery, Medical University of Łódź, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Dutkiewicz
authors.affiliation: Department of Arthroscopy, Minimally Invasive Surgery and Sports Traumatology, Medical University of Łódź, Poland.
authors.forename: Tomasz Jacek
authors.initials: TJ
authors.lastname: Zwierzchowski
mesh_terms: D000368:Aged; D001182:Arthroscopy; D024042:Collagen Type I / Q000096:biosynthesis; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D018793:Interleukin-13 / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D017006:Rotator Cuff / Q000378:metabolism* / Q000601:surgery; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000378:metabolism* / Q000503:physiopathology; D013710:Tendons / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D024042:Collagen Type I; D016207:Cytokines; D018793:Interleukin-13; D053583:Interleukin-1beta; D015847:Interleukin-4; D007371:Interferon-gamma
keywords: Collagen type I; cytokines; supraspinatus tendon resection