title: VEGF receptor mRNA expression by ACL fibroblasts is associated with functional healing of the ACL.
abstract: OBJECTIVE
  Recent advances in the treatment of ACL ruptures employ platelet-rich plasma combined with collagen to modulate growth factor release from platelets to stimulate healing. Among the most notable of these growth factors is VEGF, which is a potent mitogen and stimulator of vascular growth and healing. However, the effect of such a growth factor on healing depends on the cellular ability to bind with its receptor. The purpose of this study was to test (1) whether the strength of a tissue-engineered ACL repair is associated with VEGF receptors' mRNA expression of ACL cells and (2) whether age influences this association.
  
  
  METHODS
  Nineteen female Yucatan pigs underwent enhanced ACL repair. Biomechanical testing was performed after 15 weeks of healing. Messenger RNA of VEGF receptors 1 and 2 in ACL fibroblasts was assessed by RT-PCR. The ACL structural properties were regressed on receptor expression levels in a multivariate model including serum levels of VEGF, age, and weight as potential confounders.
  
  
  RESULTS
  While maximum load and linear stiffness were independent of VEGF receptor expression, VEGF receptor 1 was associated with displacement (positively) and yield load (negatively). In a multivariate model of VEGF receptor expression and biomechanics, age was associated with maximum load and yield load.
  
  
  CONCLUSIONS
  These findings suggest that high VEGF receptor expression, even more so at higher age, results in a more compliant scar, which in turn may lead to greater knee laxity and a compromised clinical result.
authors.affiliation: Department of Orthopedic Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA. Patrick.vavken@childrens.harvard.edu
authors.forename: Patrick
authors.initials: P
authors.lastname: Vavken
authors.forename: Fawzy A
authors.initials: FA
authors.lastname: Saad
authors.forename: Braden C
authors.initials: BC
authors.lastname: Fleming
authors.forename: Martha M
authors.initials: MM
authors.lastname: Murray
mesh_terms: D000367:Age Factors; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000378:metabolism / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation / Q000379:methods*; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D007718:Knee Injuries / Q000601:surgery*; D015999:Multivariate Analysis; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D016474:Weight-Bearing; D014945:Wound Healing / Q000502:physiology*
chemical_list: D012333:RNA, Messenger; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2