Estrutura da placenta epiteliocorial em tubarões e sua interação materno-fetal

In mammals, intrauterine nutrition of embryos occurs through the placenta. However, in placental viviparous sharks of the order Carcharhiniformes (families Leptochariidae, Triakidae, Hemigaleidae and Carcharhinidae), embryo nutrition can occur in three ways: lecitotrophy (yolk); histotrophy (uterine secretions) and placentotrophy. In this review, it is discussed the anatomical, physiological, and mainly immunological similarity between the placenta of sharks and mammals, showing that maternalfetal tolerance in placental and mammalian sharks is dependent on proteins such as indoleamine 2,3-dioxygenase, interleukin- 1 and specific proteins of gestation.