According to a Chinese longitudinal study, a higher relative abundance of L. iners bacteria in the vagina reduces the chances of human papillomavirus (HPV) being cleared spontaneously twelve months after infection. This potential therapeutic target merits further exploration as part of the fight against cervical cancer.
Sexual infection by a human papillomavirus (HPV) is common and is usually transitory, disappearing within 24 months in 80% of cases. However, for one in five women infection persists. High-risk human papillomavirus (HR-HPV) is the leading cause of cervical cancer. Sexual activity, smoking, and oral contraception are among the many factors that influence initial infection, the resolution or the onset of HR-HPV, and potential progression to cancer. In recent years, the vaginal microbiota has been added to this list. The value of this study is therefore clear, since it monitored the cervical microbiota of HR-HPV infected Chinese women presenting histologically confirmed, and mostly low-grade, cervical lesions.
More L. iners, less spontaneous clearance
A 16S rRNA analysis of the microbiota of the 73 participants in the study (aged between 24 and 68 years) showed that HPV had disappeared in 45 of the women (61.6%) by the end of the twelve-month study period. The clearance or otherwise of the virus was not due to differences in the patients’ age, the stage of the disease, the HPV subtype, the (sidenote:
Community state types
Five types of vaginal community have been identified, four dominated by lactobacilli (Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii) and a fifth characterized by a low lactobacilli content.
), or vaginal microbiota diversity. Instead, certain bacterial species seem to be involved: women depleted in enterococcus ASV_62 and enriched in Lactobacillus iners at baseline were less likely to have HPV-HR clearance at month twelve. The only exception was 22 women who underwent surgical treatment (conization) for high-grade lesions, perhaps because the immediate impact of lesion resection on HPV clearance masked the impact of the flora.
99 %
of all cervical cancer cases are linked to infection with papillomavirus, an extremely common virus transmitted through sexual contact.
4th
Cervical cancer is the fourth most common cancer in women.
570,000 women
In 2018, an estimated 570,000 women were diagnosed with cervical cancer worldwide and about 311,000 women died from the disease.
A possible link between L. iners and HR-HPV had previously been reported by a meta-analysis suggesting a two- or even three-fold higher risk of persistent HR-HPV when the vaginal microbiota is dominated by L. iners. This bacterium appears to be both flexible and adaptable, dominating the vaginal microbiota of certain women during menstruation or episodes of bacterial vaginosis. On the other hand, a vaginal microbiota dominated by L. iners (CST III) is frequently reported as one of the most common types of vaginal bacterial community among Asian child-bearing age women. Therefore, it is not yet clear from the current literature whether this particular strain of Lactobacillus should be considered beneficial, pathogenic, or both. Further work is also needed to clarify the mechanisms by which L. iners promotes persistent HPV infection or lesion progression, especially since the current study involved a small number of patients, certain confounding factors, such as smoking, were not taken into account, and it lasted only one year, whereas a 24-month follow-up is required.
Papillomavirus (HPV) is a common infection that leads to cervical cancer in some women, but not in others, for whom the virus is cleared after a few months. This resistance may be due to certain bacteria in the vaginal microbiota.
Cervical cancer is the fourth most common cancer in women. 99% of all cases follow infection with papillomavirus (HPV), an extremely common virus transmitted through sexual contact. Fortunately, in 80% of cases, HPV disappears spontaneously within two years of infection. However, for one in five women infection persists and may lead to cervical cancer. Why are some women unable to eliminate it? And why do some develop pre-cancerous lesions as a result of the virus? Chinese researchers have attempted to answer all these questions.
They believe the vaginal microbiota is involved. Previous studies had observed a vaginal dysbiosis in infected patients: high abundance of certain lactobacilli appears to reduce the risk of infection, whereas the lactobacillus L. iners is more frequent in infected patients. However, the studies’ findings are at times contradictory. As a result, researchers in Shanghai carried out this complementary study on 73 women infected by HPV and presenting first lesions of the cervix.
27%
Only 27% of women surveyed say they know that the vaginal microbiota is balanced when its bacterial diversity is low
Almost two out of three patients saw HPV clearance after one year, with the rest remaining infected. The persistence or otherwise of the virus was not due to differences in the patients’ age, the stage of the disease, the HPV subtype, the type of vaginal bacterial community (there are five main types, somewhat like blood groups), or vaginal microbiota diversity. On the other hand, the presence of two specific bacteria seemed to be involved: women with depleted levels of enterococcus ASV_62 in their cervix and enriched in L. iners were less likely to have cleared HPV after one year.
99%
of all cervical cancer cases are linked to infection with human papillomavirus (HPV), an extremely common virus transmitted through sexual contact.
4th
Cervical cancer is the fourth most common cancer in women.
604,000
In 2020, an estimated 604,000 women were diagnosed with cervical cancer worldwide and about 342,000 women died from the disease.
Will future treatments target these two bacteria (promoting one and reducing the other) to drive out HPV and prevent cervical cancer? Perhaps...if further studies support these findings. In the meantime, HPV vaccination for teenagers and regular cervical cancer screening (vaginal smears to detect precancerous lesions) for all women aged 25 to 65 is enough to prevent most cases of cervical cancer.
A study published in Molecular Psychiatry reveals that a diet emphasizing foods with an effect on brain processes via gut microbiota may reduce perceived stress in just 4 weeks. Based on their results, the authors believe that nutritional approaches aimed at modulating gut microbiota may improve mental health.
Numerous scientific studies have highlighted the involvement of gut microbiota in brain processes, mental health, behavior and cognitive function. They have opened a door for psychobiotics, i.e. interventions that impact the brain by modulating gut microbiota. Prebiotics and probiotics have already shown promising results in animal and human studies. Moreover, it is known that diet plays a major role in the composition of gut microbiota and is thought be involved in certain mental disorders.
A menu rich in prebiotics is beneficial to gut microbiota
Most studies of gut microbiota-host interactions focus on the effect of supplementation with certain foods. An Irish team decided to measure the effect of a psychobiotic diet through a single-blind, randomized, controlled clinical study. Over 4 weeks, the impact of this diet on gut microbiota, mood and perceived stress was evaluated. The researchers enrolled 24 participants and 21 healthy adult controls (18-59 years of age). The first group was offered a diet that included whole grains (5 to 8 servings), fruits and vegetables high in prebiotics (6 to 8 servings of onions, lettuce, cabbage, apple, etc.), other vegetables (3 to 4 servings) and fermented foods (2 to 3 servings of sauerkraut, kefir or kombucha) each day. They were asked to reduce sweets, sodas and fast food. Participants also received general dietary advice: food pyramid, daily calorie recommendations according to sex, etc. The control subjects received only this dietary advice. Stress experienced by all subjects was self-assessed using Cohen’s Perceived Stress Scale (PSS) at inclusion and at the end of the study.
A decrease in stress and changes in bacterial metabolic activity
At the end of the 4 weeks, both groups had benefited from the change in eating habits, with a decrease in perceived stress levels. However, this reduction was significant only in the psychobiotic diet group. In addition, the reduction in PSS score was correlated with the degree of adherence to the psychobiotic diet. Slight differences in the composition of the gut microbiota of the psychobiotic group compared to inclusion were observed (increase in Blautia wexlerae and B. obeum, decrease in Coprococcus comes, Dorea longicatena, Eubacterium rectale, Gemmiger formicilis and Bifidobacterium longum). However, metabolomic analysis revealed a significant change in 40 lipid metabolites in the psychobiotic diet group and not in the control group. This change could result from the reduced dietary fat intake associated with the psychobiotic diet, but may also suggest that gut microbiota influences mood by regulating lipid metabolism.
Results that will feed future nutritional recommendations?
According to the authors, the development of psychobiotic approaches that modulate the gut-brain axis offers possibilities for reducing stress and associated disorders. Larger studies must not only confirm the effect of such a diet on stress, but also clarify the underlying mechanisms and the role of gut microbiota in these benefits. Their results could give dietary interventions a bigger role in future nutritional recommendations for the prevention or treatment of mental disorders.
Ways of reducing anxiety and managing stress on a daily basis would be embraced by a large part of the population left exhausted by the daily grind! A study has revealed that opting for a diet rich in compounds beneficial to gut microbiota, or “psychobiotics,” may be one way to achieve this.
From having a knot or butterflies in our stomach to not being able to digest bad news... we all know how emotions can have a “visceral” effect on the constant discussion between our gut and our brain. This “gut-brain axis,” which passes through our digestive microbiota, has opened up huge avenues in terms of new knowledge... and solutions to improve our physical and mental well-being. Many scientific studies are thus revealing the role of gut microbiota in our brain mechanisms, and therefore our (sidenote:
Cognition
All the mental processes related to knowledge that involve attention, learning, intelligence, language, memory, perception, decision-making, problem-solving, reasoning, etc.
Cognition_National Cancer Institute) and mental health.
Anxiety, depression and certain mood disorders are thereby thought to be associated with intestinal dysbiosis. Given that diet plays an important role in our gut microbiota balance, it may therefore be used as a way to lift our morale, especially if it contains psychobiotic compounds (which act on the brain via gut microbiota), for example fermented foods or foods naturally rich in prebiotics.
What is a psychobiotic diet?
Particularly beneficial for gut microbiota, a psychobiotic diet emphasizes consumption of prebiotic foods (onions, lettuce, cabbage, apples, bananas, whole grains, etc.) and fermented foods (sauerkraut, kefir, kombucha, etc.).
The effect of psychobiotics through diet
Consequently, a team of researchers explored the impact of a 4-week psychobiotic diet on gut microbiota as well as on the mood and stress levels of 24 healthy adults, compared with 21 control subjects. The diet of the “psychobiotic” group was rich in foods beneficial to gut microbiota, with whole grains, fruits and vegetables high in prebiotics (onions, lettuce, cabbage, apples, bananas, etc.) and fermented foods (sauerkraut, kefir, kombucha), while sweets, sodas and fast food were reduced to a minimum. The control group was guided simply by classic nutritional advice, encouraging a balanced diet.
Image
Less stress in less than a month
At the end of the 4 weeks, both groups had benefited from the change in eating habits, with a decrease in the participants’ perceived stress levels compared to the beginning of the study. However, this reduction was significant (32%) only in the “psychobiotic” group, and the more diligently they followed their diet, the greater the reduction. Analysis of participants’ stool samples revealed only slight differences in the composition of their gut microbiota. However, a significant change in certain compounds, called lipid (sidenote:
Metabolites
Small molecules produced during cellular or bacterial metabolism. For example, short-chain fatty acids are metabolites produced by intestinal microbiota during fermentation of non-digestible complex carbohydrates (fibers, etc.).
Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25.Lamichhane S, Sen P, Dickens AM, et al An overview of metabolomics data analysis: current tools and future perspectives. Comprehensive analytical chemistry. 2018 ; 82: 387-413), was observed in the psychobiotic group (but not in the control group). According to the researchers, this may be explained by the reduced dietary fat intake associated with the psychobiotic diet, but may also suggest that gut microbiota influences mood by regulating fat metabolism.
Feeding our gut microbiota properly could therefore help us reduce our stress. Longer studies involving a larger number of individuals are now needed to confirm the effect of a psychobiotic diet on stress, and to clarify the underlying mechanisms and the role of gut microbiota in these benefits.
In schizophrenic adults, a pro-inflammatory phenotype, oxidative stress, dysbiosis and intestinal permeability are associated with aggressive behavior. This could lead to future microbial or anti-inflammatory therapies.
Schizophrenia affects 1% of the adult population, especially young adults. This psychiatric disease is thought to increase the propensity for aggressiveness, although we do not really know why. Nevertheless, some leads are emerging, involving the intestinal microbiota and a possible bacterial translocation in case of loss of watertightness of the intestinal mucosa. Following this hypothesis, a recent study profiled the diversity and composition of the intestinal microbiota, certain fecal (sidenote:
Short chain fatty acids (SCFA)
Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain.
Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25.) (short chain fatty acids) and neurotransmitters of 50 schizophrenic patients, 25 of whom had aggressive behaviors. Objective: to understand the link between inflammation, oxidation, intestinal permeability and microbiota in schizophrenic patients with aggressive behavior.
An inflammatory phenotype...
The results show that schizophrenic patients with aggressive tendencies had significantly increased levels of serum biomarkers of nucleic acid and lipid oxidation compared to non-aggressive schizophrenic patients. These pro-oxidative and pro-inflammatory responses were related to the severity of aggression, suggesting a co-implication of systemic inflammation and oxidation in the development of aggression in schizophrenia.
1%
of the global populations are affected by schizophrenia.
4 to 7
Schizophrenia may augment the propensity for aggression incidence about fourfold to sevenfold.
... coupled with bacterial dysbiosis
Schizophrenic patients with aggressive tendencies also showed a much lower bacterial diversity. This intestinal dysbiosis thus seems to be correlated with the etiology or the severity of aggressiveness in schizophrenic individuals, although it cannot be concluded that there is a causal relationship.
Furthermore, the abundance of the genus Prevotella was significantly increased, while Bacteroides, Faecalibacterium, Blautia, Bifidobacterium, Collinsella and Eubacterium coprostanoligenes were greatly depleted in the group of patients with aggressive tendencies. This change was accompanied by significant reductions in some metabolites, although the authors could not establish a causal relationship: 6 fecal SCFAs (acetic, propanoic, butyric, isobutyric, isovaleric, and isohexanoic acids) and 6 neurotransmitters (5-hydroxytryptophan, levodopa, norepinephrine hydrochloride, adrenaline hydrochloride, kynurenic acid, and histidine) were found to be significantly less present in patients with aggressive behavior.
A hypothesis to be confirmed
Considering these results as a whole, the authors hypothesize that the systemic pro-inflammatory phenotype previously observed in schizophrenics with aggressive tendencies would involve alterations of the intestinal microbiota and its metabolites, hyper-permeability of the intestinal wall allowing intestinal bacteria to reach the general circulation by causing oxidative stress, linked to the severity of the aggressive character. Thus, hyper-inflammation would have led, via the intestinal microbiota, to hyper-oxidation and ultimately to aggressiveness. This hypothesis has yet to be validated in larger-scale studies.
What do sauerkraut, kombucha, sourdough bread and kefir all have in common1? They are fermented foods, and scientists are taking increasing interest in their health benefits. An American study2 has revealed that eating a portion of fermented vegetables daily is beneficial for gut microbiota after just 6 weeks.
According to the official scientific definition, fermented foods are “foods made through desired microbial growth and enzymatic conversions of food components”3. More simply, they are processed using microorganisms such as lactobacilli (“lacto-fermented” foods) and other species of bacteria, filamentous fungi or yeast3. These foods provide beneficial microorganisms, vitamins, prebiotics and bioactive compounds of plant origin that balance gut microbiota. According to various studies3,4, they are also thought to have digestive and metabolic benefits.
5,000 fermented foods
Over 5,000 fermented foods and beverages are listed worldwide, representing between 5 and 40% of the human diet.
So why not include fermented foods in our daily diet to improve our health? A team of researchers decided to evaluate the feasibility and effects of consuming fermented vegetables (cabbage and pickles) for 6 weeks on the composition of the gut microbiota of 31 women. The participants were divided into three groups: the first consumed 100 g of fermented vegetables per day, the second 100 g of the same vegetables in brine (not fermented but preserved by acidification3) per day, and the third group, a control group, were asked to continue eating as usual. Stool samples were collected at the beginning and end of the study to analyze the gut microbiota.
Results: The gut microbiota of the women who consumed fermented vegetables was richer in Faecalibacterium prausnitzii, which according to studies are abundant in healthy people and protect against inflammation, oxidative stress and pathogenic germs. There were also fewer Ruminococcustorques bacteria, thought to promote inflammation and metabolic problems. Overall, their microbiota had more diverse microbial communities, beneficial for its balance.
In terms of digestion, the women consuming fermented vegetables experienced more bloating than those not consuming vegetables, which was expected because of the cabbage, a well-known source of natural gas! However, they also experienced less diarrhea than those consuming brined vegetables, suggesting that fermenting vegetables improves stool consistency, and less stomach upset than the other two groups. Finally, in terms of regularity, while 70 to 90% of the women in the “cabbage-pickles” groups stuck to their diet, some found it tough on reaching the end of the 6 weeks...
This pilot study suggests that consuming 100 g of fermented vegetables daily for 6 weeks is feasible and beneficial for gut microbiota: more work is now necessary to determine whether fermented vegetables could effectively fight dysbiosis. Its authors suggest offering participants a wider variety of vegetables to reduce the side effects and boredom.
March is Endometriosis Awareness Month. Painful, complex and often undiagnosed, endometriosis is a chronic gynecological disease affecting one in every 10 women of reproductive age1.
Actively supporting this worldwide campaign since 2021, Biocodex Microbiota Institute keeps on exploring the link between the microbiota and endometriosis. Can the vaginal microbiota be used as a tool for predicting the severity of the disease? What about the gut microbiota? Is the vaginal microbiota to blame for painful periods? All your questions answered here.
On this occasion, the Institute sheds the lights on a little-known topic: periods and endometriosis. Do gut and vaginal microbiota play a role in it?
They explore, they search, and they raise awareness about the importance of microbiota on health. To celebrate International Day of Women and Girls in Science (11 February), the Biocodex Microbiota Institute is handing the floor to women scientists particularly active in microbiota research.
Launched by the United Nations in 2015, International Women and Girls in Science Day (February 11) intents to recognize the critical role women and girls play in science, technology, engineering, and mathematics (STEM) and to promote efforts to achieve gender equality in science.
They are women. They came from Finland, France, USA, Canada…They are making great achievement in microbiota research. To celebrate International Day of Women and Girls in Science (11 February), the Biocodex Microbiota Institute is handing the floor to women researchers and physicians particularly active in microbiota research.
Launched by the United Nations in 2015, International Women and Girls in Science Day (February 11) intends to recognize the critical role women and girls play in science, technology, engineering, and mathematics (STEM) and to promote efforts to achieve gender equality in science.
"What a lovely dedication to women and girls in science. Thank you for the kind mention and well done to all for your achievements." - Vanessa Carter (From Biocodex Microbiota Institute on LinkedIn)
"Thank you for this acknowledgment that reinforces my commitment to promoting microbiota science to the widest audience for health prevention. Well done to everyone for their achievements." - Anne-Sophie ALVAREZ (From Biocodex Microbiota Institute on LinkedIn)
Male idiopathic urethritis is treated largely using probabilistic antibiotic therapy. Researchers1 seeking a more targeted approach to these common infections have analyzed the urinary and urethral microbiota of symptomatic subjects, giving consideration also to their sexual orientation. They have identified “new” bacteria potentially involved in such infections, including Haemophilus influenzae.
Urethritis is a sexually transmitted infection (STI) caused mainly by Neisseria gonorrhoeae, but also by Chlamydia trachomatis or Mycoplasma genitalium, and less commonly by a virus, such as herpes simplex. But up to 50% of non-gonococcal urethritis is considered to be idiopathic. In rare cases it is non-infectious and of undetermined etiology, which poses a diagnostic and therapeutic challenge for clinicians. Probabilistic antibiotic therapy is used widely in such cases, but can result in inadequate or excessive treatment with a risk of antibiotic resistance. Recent studies also suggest that the infectious agents responsible for non-gonococcal urethritis in men who have sex with women (MSW) are not the same as in those who have sex with men (MSM).
Exploration of urinary and urethral microbiota in relation to sexual orientation
Some Australian researchers sought to determine which infectious agents, apart from those already known, might contribute to non-gonococcal urethritis in men, taking into account their sexual practices and the biological sex of their partner. For this, they conducted a case study including 199 men, 96 of whom had symptoms of idiopathic urethritis and 103 of whom did not, who served as controls. The median age of participants was 31 years, 73 had had a sexual relationship with a man in the month prior to inclusion (classified as MSM), and the remainder were classified as MSW. For all of them, the researchers had samples of urinary and urethral microbiota available for sequencing analysis.
Urethritis not always “idiopathic”: hope for more targeted treatments
Their results revealed that Haemophilus influenzae, which naturally colonizes nasopharyngeal microbiota, was more abundant in MSM participants with idiopathic urethritis. In addition, H. influenzae was clearly associated with clinical features such as urethral burning, dysuria and purulent discharge. The researchers believe having oral sex without a condom could be the main mode of contamination by this bacterium. They observed more of the genus Corynebacterium in affected MSW, which they found surprising since it is considered commensal in male genital microbiota. The scientists conclude that some specific species of Corynebacterium may become pathogenic when present in abundance. There were also more Ureaplasma, Staphylococcus haemolyticus, Streptococcuspyogenes, Escherichia and Streptococcuspneumoniae in the urinary and urethral microbiota of symptomatic subjects, so they may all promote urethritis.
Possible infectious causes of non-gonococcal urethritis, previously described as idiopathic, have thus been discovered. If these results are confirmed by other studies, doctors may eventually be able to offer their patients more targeted treatments.
Vaginal microbiota # 14
Cervicovaginal microbiota: a marker for persistent papillomavirus infection?
