What is the relationship between infantile hemangiomas and the placenta?

Updated: Feb 06, 2019
  • Author: Richard J Antaya, MD; Chief Editor: William D James, MD  more...
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Answer

Neither the cause nor the cell of origin of infantile hemangiomas has been definitively elucidated. Theories abound and several lines of evidence support several divergent theories of the cell of origin, including placental tissue, endothelial progenitor cells (EPCs), and mesenchymal stem cells. [16]

A distinct group of tissue-specific markers, including Lewis Y, merosin, and FcγRII, but most notably glucose transporter 1 (GLUT-1), are uniquely coexpressed by hemangiomas and placental microvessels, suggesting a unique relationship between hemangiomas and placental microvessels. Two theories postulated to explain this observation include (1) colonization of receptive mesenchyme by potentially abnormal angioblasts switched toward a placental endothelial phenotype and (2) embolic placental endothelial cells that have reached fetal tissues from chorionic villi through right-to-left shunts.

The placenta and hemangioma share a similar life cycle of robust vascular growth. The placenta produces very high levels of the proangiogenic cytokine, vascular endothelial growth factor (VEGF). As a protective mechanism against uncontrolled angiogenesis in the fetus and mother, a soluble form of the VEGF receptor, sFlt-1, found in both amniotic fluid and maternal serum, is also produced by the placenta. sFlt-1 binds circulating VEGF, preventing excessive angiogenesis in nonplacental tissues. Postpartum, the connection to the placenta and sFlt-1 is removed, abrogating this negative feedback and allowing proliferation of cells, such as those in hemangiomas, responsive to VEGF. [17, 18]


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