three harmony parts. a new study finds that the placenta is home to a small community of bacteria.
Illustration (animation) © Science / AAAS
The researchers found a small community of bacteria living in a most unlikely place: the placenta, the the organ that nourishes the developing fetus through the umbilical cord. The discovery overturns the conventional wisdom that the placenta is sterile. The study also suggests that these microbes can come from the mouth, saying that good oral hygiene may be important for a healthy pregnancy.
The placenta is a shaped mass of tissue crepe on the side of the uterus that provides oxygen, food, and waste removal to a fetus. Medical experts have long assumed that all bacteria in the body must have been picked up during its passage through the vagina after childbirth. But more recently, researchers have realized that the baby has a community of bacteria in his gut when he was born. And these bacteria do not match those in the vagina, which suggests another source, such as the placenta, says specialist in fetal medicine Kjersti Aagaard from Baylor College of Medicine in Houston, Texas.
Aagaard and her colleagues are employees of the US human microbiome project, which studies microbiomes-communities of bacteria, fungi and viruses that live in various places on and in our bodies. They sought placental microbiome by analyzing carefully collected placentas from 320 pregnancies. The researchers extracted DNA and sequenced to placentas extracts and whole bacterial genomes to identify and quantify microbial species and genes they wore. This analysis revealed low levels of a variety of bacteria, mostly nondisease causing strains Escherichia coli , which dominate our intestinal tract, but other five major groups, or phyla. Most were minor species known to provide services such as the metabolism of vitamins.
Surprisingly, the mixture of bacteria in the placenta more like the microbiome in the mouth of an adult human being as the vagina, skin, bowel, or other microbiomes of body, the team reports today Aagaard science Translational Medicine . Researchers think that microbes can reach the placenta from the mouth of the mother by his blood, perhaps when she brushes her teeth and dislodge in the blood. This is useful because it is a well-known correlation between gum disease and premature birth. Indeed, the picture of bacteria in the placenta differed in women who gave birth early, before 37 weeks.
"This again underlines the importance of oral health" during pregnancy, said Aagaard. In fact, women may need to pay attention to their teeth before they may become pregnant because the placenta develops early in pregnancy, she said. This can be a challenge for low-income women who can not afford dental care, Aagaard said. The team also found a correlation between the composition of the microbiome and placental infections of urinary tract, suggesting that such diseases or antibiotics taken to address could change the microbiome in unhealthy ways.
"This is the first study to suggest that all placentas contain a small amount of bacteria," says perinatal researcher Roberto Romero of the National Institute of Child Health and Human Development campus in Detroit, Michigan . "These bacteria can live and have a purpose," as seeding intestinal microbiome of the fetus or the construction of the immune system, adds the Indira Mysorekar biologist at Washington University in St. Louis, who reported the discovery of bacteria within certain placental cells.
However, Romero and others warn that it is too early to say exactly how the microbiome placental got there and what it does . the bacteria could have been in the womb before pregnancy and has evolved to resemble those of the mouth, said Mysorekar. Despite these unknowns, says microbiologist Seth Bordenstein of Vanderbilt University in Nashville, the discovery of a placental microbiome "continues to build the snowball that no tissue in the human body is sterile."
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