![Una il·lustració de la macrobiota intestinal](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 9"%3E%3C/svg%3E)
The Isala project started in Belgium in 2020 and within days had already recruited over 5,000 female participants. This success has inspired other research teams in Europe and other countries to join the initiative. They have created an international network – a sisterhood, as the researchers like to call it – pursuing the same goal: to advance knowledge of women's health. In each country, the project adopts a different name, in honor of a pioneering female scientist. In Belgium, for Isala, it was the country's first female doctor. In Spain, the project is called Manuela, in honor of Manuela Solís i Claras from Valencia, the first woman to graduate in medicine from the University of Valencia, who dedicated her life to improving the health of mothers and children.
From infertility to endometriosis, why the vaginal microbiome is key to female health
The bacteria that inhabit the vagina could help understand aspects such as infertility or endometriosis
For years, research on the human microbiome has focused almost exclusively on the gut. But there are also millions of microorganisms – especially bacteria, but also fungi and viruses, and yeasts – lining the vagina. Although they have not been studied until recently and, therefore, little is known about them, recent studies are beginning to shed light on how this ecosystem is key to women's health and can affect conditions such as endometriosis.
"For a long time, the vaginal microbiome was an understudied field, it was considered a taboo subject or it was thought to be much less diverse and complex than the gut microbiome," explains to ARA Caroline Dricot, a researcher at the University of Antwerp.
However, "we now know that it is much more diverse than we imagined and that it plays a fundamental role in women's health," emphasizes this scientist, one of the main speakers at the 12th edition of the international congress Barcelona Debates on Human Microbiome, held this week at Cosmocaixa, and organized by IrsiCaixa coinciding with World Microbiome Day.
Dricot has presented the results of the Isala project, a citizen science initiative driven by microbiologist Sarah Leeber, from the Belgian University of Antwerp, which was launched in 2020 and has produced one of the most comprehensive maps of the vaginal microbiome. The study analyzed samples from 3,345 healthy Belgian women aged 18 to 98 years to answer a seemingly simple, but until now unanswered, question: what does a healthy vaginal microbiome look like?
The results show that 78% of participants have microbiomes dominated by bacteria of the genus Lactobacillus, considered the great guardians of vaginal health. These microorganisms hinder the growth of pathogens and help prevent infections, pregnancy complications, and fertility problems. "We knew that lactobacilli protected the vagina because they produce lactic acid, but now we want to understand many other functions they might have," points out Dricot.
This study also confirms that the vaginal microbiome, like the intestinal one, changes throughout life and is strongly influenced by estrogens. Menopause, having had children, breastfeeding, or certain contraceptives modify its composition. Thus, researchers have observed, for example, that species such as Lactobacillus crispatus and Lactobacillus jensenii are more frequent in women with high estrogen levels, while more diverse microbiomes are associated with menopause or postpartum.
The research has also brought surprises, such as some vaginal lactobacilli being capable of producing riboflavin or vitamin B2, an essential nutrient during menstruation, pregnancy, and breastfeeding. Scientists suspect that these microorganisms could contribute to meeting part of women's nutritional needs.
The link with fertility and endometriosis
Another of the emerging lines is the relationship between the microbiome and endometriosis, a disease that affects one in ten women of reproductive age. The researcher from Pompeu Fabra University Mireia Vallès Colomer leads the MiENDO project, which will study whether certain intestinal and reproductive tract microorganisms, capable of modulating sex hormones, are related to this disease and to the infertility problems suffered by between 30% and 50% of those affected. The objective is to identify new leads that help to better understand a pathology still surrounded by unknowns.
