Menstrual blood proteome
August 1, 2012 § Leave a comment
It’s hard to believe, but, according to Donald Siegel at the New York City Office of Chief Medical Examiner, not much is known about the molecular composition of menstrual blood. To remedy that, he and his colleagues at NYC OCME, which is part of the New York City Department of Health and Mental Hygiene and does forensic testing for NYC, recently did a mass spectrometric analysis of menstrual blood to find out what proteins it contained.
Menstrual blood is the product of a monthly cycle in women when the uterus prepares for pregnancy (interesting fact: Besides humans and closely related primates, only some bats and elephant shrews menstruate). Near the beginning of the cycle, just after menstruation has ended, cells lining the uterine wall multiply. About 14 days after the start of menstruation, the female ovulates and produces an egg. The uterine wall gets ready for a fertilized egg to implant. If a fertilized egg fails to show up or implant, the uterine lining sloughs off and leaves the body through the vagina. Once the lining is expelled, the cycle starts all over again.
Problems with the uterine lining may contribute to infertility. Researchers have looked into the molecular composition of uterine lining during the menstrual cycle. “However, this research typically uses uterine wall biopsies, and the information obtained from them may be specific to the site of biopsy,” notes Siegel.
Siegel, along with Heyi Yang, Bo Zhou and Mechthild Prinz, decided to take a more global view of menstrual blood. By using mass spectrometry on the menstrual blood collected from two women, they identified 1,061 proteins. They reported in their Molecular & Cellular Proteomics paper that, out of these proteins, 385 were unique to menstrual blood.
“We believe our identification of many of the same proteins found by biopsy may make menstrual blood a convenient, noninvasive source of material for research and possible diagnosis of infertility and uterine disease,” says Siegel. He also points out that, from a forensic standpoint, it’s very important to be able to tell apart menstrual blood from circulating blood spilled from veins and arteries.
Siegel says his team has a lot of work ahead. The blood from the two women was taken when the women were in the middle of their periods. It’s possible that the proteome of menstrual blood changes over the duration of menstruation; those differences need to be established. Also, the proteome of menstrual blood may change with age and ethnicity. “We have collected menstrual blood from 50 women of different ages and ethnicities during each day of their periods and have begun a proteomic analysis of these samples,” says Siegel.
He says the investigators hope to find menstrual blood marker proteins that are consistently found throughout menstruation. They also will make the data freely available to the biomedical community.