title: In vivo monitoring of angiogenesis during tendon repair: a novel MRI-based technique in a rat patellar tendon model.
abstract: OBJECTIVE
  Recent in vivo studies were able to show the impairing effect of neoangiogenesis in degenerative tendon diseases. Clinical in vivo monitoring of angiogenesis in injured tendons therefore seems to be crucial for an accurate therapeutic approach. The aim of this study was to develop a novel magnetic resonance imaging (MRI)-based technique for observing angiogenesis during tendon healing in vivo.
  
  
  METHODS
  Tendinopathy was induced by an in situ freezing model of rat patellar tendon and monitored after 7, 14, and 28 days. Animals were randomly divided into an imaging and immunohistochemical group. MRI with a 'blood pool' contrast agent was used to determine neoangiogenesis during tendon healing. MRI was compared to histochemical staining and quantification of blood vessels in injured and native tendons.
  
  
  RESULTS
  MRI data revealed a peak in changes in the transverse relaxation rate (ΔR 2*), which is proportional to relative blood volume, 7 days after surgery and decrease until day 28. Histological microvessel density and vascular endothelial growth factor synthesis were also most evident at day 7 and decreased over time.
  
  
  CONCLUSIONS
  The current results are demonstrating a time-dependent correlation between microvessel density and ΔR 2*. Thus, MRI-based evaluation of angiogenesis in the tendon might be a new promising technique for in vivo monitoring of angiogenesis and therapy response in the future.
authors: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany. richard.stange@ukmuenster.de.|Department of Trauma, Hand and Reconstructive Surgery, Institute of Experimental Musculoskeletal Medicine (IEMM), University Hospital Münster, Waldeyerstr. 1, 48161, Münster, Germany. richard.stange@ukmuenster.de.
authors: Richard
authors: R
authors: Stange
authors: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.|Medical Department III, University Hospital Aachen, RWTH Aachen, Aachen, Germany.
authors: Hacer
authors: H
authors: Sahin
authors: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.
authors: Britta
authors: B
authors: Wieskötter
authors: Department of Clinical Radiology, University Hospital Münster, Münster, Germany.|Department of Radiology, University Hospital Cologne, Cologne, Germany.
authors: Thorsten
authors: T
authors: Persigehl
authors: Department of Clinical Radiology, University Hospital Münster, Münster, Germany.
authors: Janine
authors: J
authors: Ring
authors: Department of Clinical Radiology, University Hospital Münster, Münster, Germany.|Department of Radiology, St. Franziskus Hospital Münster, Münster, Germany.
authors: Christoph
authors: C
authors: Bremer
authors: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.
authors: Michael J
authors: MJ
authors: Raschke
authors: Department of Clinical Radiology, University Hospital Münster, Münster, Germany.
authors: Volker
authors: V
authors: Vieth
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001810:Blood Volume; D003287:Contrast Media; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D018919:Neovascularization, Physiologic; D017847:Patellar Ligament / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D017208:Rats, Wistar; D052256:Tendinopathy / Q000601:surgery; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014945:Wound Healing
chemical_list: D000199:Actins; D003287:Contrast Media; D042461:Vascular Endothelial Growth Factor A; C498862:Acta2 protein, rat