title: Comparative Analysis of the Extracellular Matrix Composition in Proliferating and Involuted Infantile Hemangiomas.
abstract: BACKGROUND
  Changes in the composition of the extracellular matrix (ECM) occur between the proliferating and involuted phases of infantile hemangiomas (IH), and are associated with angiogenic growth. We examined the composition of the ECM in proliferating and involuted IHs and assessed correlations between the composition of the ECM and whether the IH was in the proliferating or the involuted phase.
  
  
  METHODS
  We evaluated IH samples from a cohort of patients who had five proliferating IHs and five involuted IHs. The following ECM molecules were analyzed using enzyme-linked immunosorbent assays and immunohistochemistry: laminin, fibronectin, collagen type I, collagen type II, and collagen type III.
  
  
  RESULTS
  The involuted IHs had higher levels of deposition of collagen type III than the proliferating IHs. The median values (interquartile ranges) were 1.135 (0.946-1.486) and 1.008 (0.780-1.166) (P=0.019), respectively. The level of laminin was higher in involuted IHs than in proliferating IHs, with median values (interquartile ranges) of 3.191 (2.945-3.191) and 2.479 (1.699-3.284) (P=0.047), respectively. Abundant collagen type III staining was found in involuted IHs. Laminin α4 chain staining was clearly present within the basement membrane adjacent to the blood vessels, and was significantly more intense in involuted IHs than in proliferative IHs.
  
  
  CONCLUSIONS
  Involuted hemangiomas showed extensive deposition of collagen III and laminin, suggesting that differences in the composition of the ECM reflect stages of the development of IHs. This pattern may be due to the rapid senescence of IHs.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Daegu Fatima Hospital, Daegu, Korea.
authors.forename: Hyochun
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Plastic and Reconstructive Surgery, Daegu Fatima Hospital, Daegu, Korea.
authors.forename: Hannara
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Ho Yun
authors.initials: HY
authors.lastname: Chung
authors.affiliation: Vascular Birthmark Institute of New York, Lenox Hill and Manhattan Eye, Ear, and Throat Hospitals, New York, NY, USA.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: O
authors.affiliation: Vascular Birthmark Institute of New York, Lenox Hill and Manhattan Eye, Ear, and Throat Hospitals, New York, NY, USA.
authors.forename: Milton
authors.initials: M
authors.lastname: Waner
keywords: Aging; Collagen; Extracellular matrix; Hemangioma; Laminin