The angiogenic peptide vascular endothelial growth factor is expressed in foetal and ruptured tendons.
The Achilles tendon is one of the most common sites of injury and rupture. Evidence suggests that local vascularisation is involved in this aetiology. We investigated the expression of one important angiogenic factor, the vascular endothelial growth factor (VEGF), in normal and pathologic human Achilles tendons using immunohistochemical, biochemical, molecular and cell biology methods. VEGF could be immunostained in tenocytes of ruptured and foetal Achilles tendons, but not in normal adult ones. In microvessels, the VEGF receptor VEGFR-1 (flt-1) could be visualised as well. High VEGF levels were measured in homogenates from ruptured adult, lower ones in foetal and negligible concentrations in normal adult Achilles tendons using enzyme-linked immunoassay (ELISA) and Western blot experiments. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed that the splice variants VEGF121 and VEGF165 are exclusively expressed. In tenocytes cultivated from newborn rat Achilles tendons, hypoxia or epidermal growth factor (EGF) raised VEGF production moderately whereas their combination resulted in a strong, synergistic induction. These results prove the presence of an angiogenic peptide and vascularisation in ruptured and foetal tendons and support the view that microtrauma or degeneration in the Achilles tendon precedes its rupture.
Pufe
T
T
University of Kiel, Department of Anatomy, Germany.
Petersen
W
W
Tillmann
B
B
Mentlein
R
R
D000125:Achilles Tendon / Q000187:drug effects / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D000328:Adult; D017398:Alternative Splicing; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007124:Immunoenzyme Techniques; D008222:Lymphokines / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013708:Tendon Injuries / Q000378:metabolism* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D004815:Epidermal Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1