Immune cells called Natural Killer (NK) may be crucial for the development of the fetus, informs the journal Immunity.
NK cells are primarily concerned with destroying neoplastic cells and pathogens.
By analyzing the behavior of murine NK cells, Zhigang Tian of China’s Hefei University of Science and Technology and colleagues found a type that is found exclusively in the uterus and only during pregnancy. Scientists called these cells “uterine NK” cells and showed that they produce significant amounts of two proteins that are essential to the developing fetus and prevent low birth weight.
The first protein – pleiotrophin – stimulates the development of blood vessels, bones, cartilage and the brain. The second – osteoglycin (osteoglycin) influences the development of the heart, skin and eyes.
Examination of tissue samples from the uterines of 54 women found that those who recently had a miscarriage had fewer uterine NK than women who had a successful pregnancy.
Genetically modified mice incapable of producing these cells produced offspring that were twice smaller than normal. In contrast, artificial administration of NK cells during pregnancy caused the offspring to grow larger.
Tian’s scientists hope that uterine NK cells could help women who have repeated miscarriages or whose babies are born too young. Cells could be administered intravenously or vaginally.