title: Expression Patterns of HIF-1α Under Hypoxia in Vascular Smooth Muscle Cells of Venous Malformations.
abstract: OBJECTIVE
  The molecular pathophysiology of venous malformations (VMs), which are a type of vascular malformation, is poorly understood. Until now, it is known that VM lesions are related to the process of angiogenesis. Because angiogenesis is induced under hypoxic conditions, hypoxia is thought to be important in VM lesion formation. Therefore, we examined the implications of hypoxia on the biological behavior of VM vascular smooth muscle cells (VSMCs). In doing so, we investigated the expression patterns of hypoxia-inducible factor-1α (HIF-1α), which plays a key role in hypoxia-induced angiogenesis, to provide a further understanding of the molecular mechanisms involved in VM.
  
  
  METHODS
  Vascular smooth muscle cells from 5 normal veins and 5 VM lesions were cultured under moderate hypoxic conditions (3% O2, 5% CO2). The effects of hypoxia on HIF-1α expression were measured by immunocytochemical staining, reverse transcription-polymerase chain reaction, and real-time reverse transcription-polymerase chain reaction.
  
  
  RESULTS
  Overall, the expression of HIF-1α in cells was high after exposure to hypoxia for 6 or 12 hours, but decreased after 24 hours of hypoxia. HIF-1α expression in VM VSMCs was 2 times higher than that in normal VSMCs. Immunocytochemically, HIF-1α was mainly located in the nucleus and the intensity in VM VSMCs was stronger after 6 and 12 hours of hypoxia when compared to the expression pattern of HIF-1α in VSMCs from normal tissue. This suggested that VM tissue is more susceptible to the effects of hypoxia than normal tissue.
  
  
  CONCLUSIONS
  These results indicate that the high expression of HIF-1α in VM VSMCs under hypoxic conditions could be an important factor for stimulating downstream angiogenesis in VM. Furthermore, the results of this investigation could provide the basis for future studies of VM pathophysiology, and ultimately lead to the development of new therapeutic approaches.
authors.affiliation: From the *Department of Plastic and Reconstructive Surgery, Kyungpook National University, School of Medicine, and †Vascular Anomalies Center, Kyungpook National University Hospital, Daegu, Korea; ‡Vascular Birthmark Institute of New York, Lenox Hill Hospitals, New York, NY; §Department of Dermatology, ∥Department of Radiology, and ¶Department of Vascular Surgery, Kyungpook National University, School of Medicine, Daegu, Korea; and #Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, NC.
authors.forename: Ho Yun
authors.initials: HY
authors.lastname: Chung
authors.forename: Seok Jong
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Seung
authors.initials: S
authors.lastname: Huh
authors.forename: Hyung Kee
authors.initials: HK
authors.lastname: Kim
authors.forename: O Hyun
authors.initials: OH
authors.lastname: Kwon
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Lim
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Oh
authors.forename: Tae Jung
authors.initials: TJ
authors.lastname: Kim
authors.forename: Teresa M
authors.initials: TM
authors.lastname: O
authors.forename: Milton
authors.initials: M
authors.lastname: Waner
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D002478:Cells, Cultured; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007150:Immunohistochemistry; D009131:Muscle, Smooth, Vascular / Q000098:blood supply / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054079:Vascular Malformations / Q000378:metabolism* / Q000503:physiopathology; D014680:Veins / Q000002:abnormalities* / Q000378:metabolism
chemical_list: D015415:Biomarkers; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit