Fertility and endometriosis: a research update from Inserm

©2019 Flore Avram/Inserm

Today, around 1 in 8 couples seek help because they are struggling to conceive. This is probably linked to the fact that couples are starting families later in life than before, or because they are setting aside the taboos linked to infertility and are more willing to seek help. Infertility has therefore become a public health problem, and the scientific community is rallying in response.

Where are we with research into this area, which lies at the heart of current societal problems? What are the prospects for the transfer of such research into clinical practice? Fertility research covers many different areas. The aim of this press kit is not to tackle them exhaustively, but to highlight the sectors in which research is making progress.

When research makes progress, everyone’s health benefits.

  1. Research into combating infertility

The term infertility is used when a couple are unable to conceive a child naturally after 12 months of trying. This term covers cases of total sterility, where there is no hope of natural conception, and subfertility, the majority of cases, in which couples have a reduced – but not zero – chance of achieving a pregnancy.

Cases of infertility are divided into 4 categories based on their cause:

– 30% are female-related;

– 30% are male-related. In men, azoospermia and oligospermia are the two leading causes of infertility identified to date;

– 30% are combined, meaning that they are caused by reduced fertility in both partners;

– 10% are unexplained.

In women, with the exception of mechanical causes affecting the fallopian tubes – when they are impaired or blocked (usually following an infection) – or uterus, endometriosis and abnormal ovulation are the most common causes of infertility.

Causes of abnormal ovulation include polycystic ovary syndrome (which affects around 10% of women around the world), hyperprolactinemia, and primary ovarian insufficiency (which may also be a side effect of chemotherapy).

Current research seeks to both improve understanding of the causes of infertility, and also to study new therapies or management methods that aim to increase the chances of conception.

  • Improving understanding of the causes
  • The genetic approach

Many researchers are studying the genetic causes of ovarian insufficiency. Several fertility problems are caused by certain genes not working, or not working properly. One rapidly growing area of research, due in particular to the improvement in high-throughput screening methods, is the study of genetic variants.

The Inserm laboratory led by Nadine Binart, for example, is working on primary ovarian insufficiency (POI), which is characterized by the inability of ovarian follicles to mature or by diminished ovarian reserve. Based on DNA analysis of women with POI, researchers are working to isolate the genes that are involved or altered in their genetic make-up. This approach is helping to improve understanding of the disease, but does not make it possible to provide specific treatment to these women, as sterility becomes definitive once there are no more eggs left in their ovaries. Preventive management can however be introduced if the genetic abnormality is found before the ovarian reserve is entirely depleted – for example, during family testing. This is the role of clinical research, which makes it possible to lessen the impact of these diseases when mutations are identified in affected families, to inform young patients about the risk of losing their eggs over time, and to introduce fertility preservation methods if appropriate.

  • The hormonal approach: the example of kisspeptin and prolactin

It is well-established that breastfeeding results in increased secretion of prolactin (PRL) by the pituitary gland, inhibiting a woman’s ability to ovulate. This prevents the onset of a new pregnancy. Some diseases also lead to an increase in PRL, including tumors of the pituitary gland from which this hormone is secreted. These cases of hyperprolactinemia, which result in period problems and infertility, are a leading cause of anovulation. In 2011, the Inserm team led by Jacques Young and Nadine Binart revealed the underlying mechanism that blocks ovarian function. Using a mouse model of the disease, the researchers showed that PRL inhibits secretion of a neurohormone called kisspeptin, which is the starting point for the entire hormone cascade responsible for ovarian cyclicity. In a mouse model, administration of kisspeptin made it possible to restore ovarian cyclicity despite the hyperprolactinemia.

This pathophysiological discovery explains the link between infertility and hyperprolactinemia for the first time, and points the way to developing innovative therapies. The basic concept has recently been validated in women,[1] which will make it possible to offer a therapeutic alternative for patients who do not respond to the drugs currently used.

1.2. Preserving fertility: areas of research and latest findings

Specialist “oncofertility” consultations have developed extensively in recent years and should now be an integral part of the care pathway for all young female patients with cancer. Several “fertility preservation” techniques designed to cryopreserve gametes, or preserve reproductive capacity, are now available, and others are currently in development. In France, since 1994, these methods have been included in various pieces of bioethics legislation. Article L.2141 11, modified by law 2011-814 of July 7, 2011, states that “All persons whose fertility is likely to be impaired by their medical care, or whose fertility risks being prematurely impaired, may have their gametes or reproductive tissue collected and preserved with a view to their later use of assisted reproductive technology, or with a view to preserving and restoring their fertility.” Fertility preservation methods are also included in the 2014-2019 Cancer Plan, which stipulates that “all patients must have access to cancer treatments, and innovative treatments in particular.”

  • Improving gamete preservation

Several techniques for cryopreserving female gametes are currently available. The standard method involves freezing mature eggs or embryos obtained from these eggs. It is not however suitable for prepubescent girls, who need to begin treatment urgently, and can also present problems in patients with hormone-sensitive cancers. Therefore, other techniques, although still considered experimental, may be offered in these situations.

Improving the available methods and developing new strategies is currently a major focus for oncofertility. This is one of the areas of research on which the Inserm team led by Nadine Binard and Charlotte Sonigo is working, in collaboration with Prof. Michael Grynberg.

  • Using anti-Müllerian hormone

Chemotherapy reduces fertility through a direct toxic effect on the ovaries. Cyclophosphamide, which is commonly used in cancer treatment, causes massive destruction of the germ cells contained in the ovarian follicles. In a mouse model, researchers have recently shown that treatment with anti-Müllerian hormone, which is normally secreted by the ovaries, can limit reduction of follicular reserve during chemotherapy. Use of anti-Müllerian hormone is therefore a promising approach to fertility preservation.

1.3. The role of new technologies: Using artificial intelligence in reproductive research

The store of germ cells contained in the follicles constitutes the ovarian reserve. Assessing the quantity of these germ cells is a common way of providing information on ovarian physiology and of measuring the impact of the environment on the ovaries. The standard method used in mice is time-consuming and tedious. In conjunction with a company specializing in artificial intelligence, Inserm researchers have recently developed an automated artificial intelligence method for follicle counting that uses a deep learning approach.[2] This new tool will be made available to the fertility research scientific community, saving a great deal of time and enabling better reproducibility of data.

  1. Research into combating endometriosis

Endometriosis is a complex disorder characterized by chronic inflammation due to the presence of tissue resembling the uterine lining outside the uterus. This “ectopic uterus” continues to respond to ovarian hormones, which in some women can cause severe pain and sometimes infertility. In response to increased visibility of the disease in the media, notably due to the work of patient organizations, the French health minister has announced an action plan to improve management of endometriosis. In terms of research, there has been a surge in studies of endometriosis over the last 5 years. Around 1,200 articles per year are being produced by researchers around the world, helping to advance understanding of this disorder.


©2019 Flore Avram/Inserm

  • An estimated 1 in 10 women have some form of endometriosis.
  • The locations of endometriosis lesions vary.
  • Endometrial cell reflux during periods occurs in 90% of women, but only 10% of them develop disease.
  • The disease is typically described as having 4 stages, based on the extent and depth of lesions; however, there is no correlation between disease symptoms and severity.
  • There are 3 forms of endometriosis: superficial peritoneal endometriosis, ovarian endometriosis (or endometrial cyst, or endometrioma), and deep endometriosis.

2.1. Improving understanding of the causes

 The epidemiological approach

At present, little is known about the causes of endometriosis, its natural history, and the factors affecting its progression. Epidemiological research plays a crucial role in advancing knowledge in this area. There are only a few large epidemiological cohorts around the world in which these aspects can be explored. The largest cohort for exploring endometriosis risk factors is currently a cohort of 116,430 American female nurses who were between 25 and 42 years old in 1989. The risk factors identified in the literature and confirmed in this cohort include: low birth weight, early menstruation, low body mass index, and short menstrual cycles (under 24 days).[3] However, beyond these factors, little information is available on the causes of the disease, and its natural history is largely unknown. The following table is based on a review of the literature published in August 2018:


*The positive association between smoking and reduced risk of endometriosis may be explained by the antiestrogenic effect of tobacco. This would confirm the therapeutic interest of estrogen blockers, which are available in drug form: far more suitable than cigarettes, whose harmful effects have been widely documented.

In a bid to improve understanding of this disease, several epidemiological studies are being launched in France by the team led by Marina Kvaskoff, Inserm epidemiologist and researcher. These include a recently formed patient cohort dedicated to the study of endometriosis: the ComPaRe-Endometriosis cohort. The study team’s objective is to have enough women in the cohort to obtain robust findings in relation to the many questions that are still unanswered about this disease. In less than 6 months, over 8,000 women have already taken part in the study. The team aims to recruit 15,000 to 20,000 participants, and a broad call for participation has gone out to women with endometriosis or adenomyosis (a form of endometriosis limited to the muscle wall of the uterus) to help speed up research into these disorders simply by completing online questionnaires about their experience of the disease ( The study initially looks to explore the natural history of the disease (change in the symptoms and characteristics of the disease over time), and to identify the factors that determine its progression and result in better response to treatment. This research will also make it possible to describe the circumstances of diagnosis and the patient care pathway, and to assess the impact of the disease on patients’ daily lives.

Endometriosis is also being studied within large French cohorts, such as the CONSTANCES cohort, a prospective study of 200,000 men and women (105,000 women) representative of the French population. Marina Kvaskoff’s team has developed an epidemiological research study to determine the prevalence and incidence of the disease in France, and to explore its risk factors within this cohort. Other studies are currently in development and will be conducted in other cohorts in due course.

  • The environmental approach

Several epidemiological studies have explored the associations between organochlorine chemicals (solvents, pesticides, insecticides, fungicides, etc.) and endometriosis, but their results have been inconsistent. A French meta-analysis of 17 studies[4] published in February 2019 attempted to draw more robust findings. The risk of developing endometriosis was 1.65 times higher in women exposed to dioxins, 1.70 times higher for those exposed to polychlorinated biphenyls (PCB), and 1.23 times higher for organochlorine pesticides. Although statistically significant, these estimates should be considered with caution due to the significant heterogeneity of the studies and the small estimated effect size. The level of evidence was judged to be “moderate” with a serious risk of bias, supporting the need to conduct further well-designed epidemiological research in order to fill the persistent data gaps.

  • Using the genetic and epigenetic approach for early detection

Detecting endometriosis in the early stages, before patients experience symptoms, would make it possible to improve patient care. Although the heritability of endometriosis has been estimated at 50%, it is highly complex and clearly highly polygenic. Numerous candidate genes have been studied from this perspective in analyses of disease predisposition. Initial results have shown that there is no gene for endometriosis, but that the existence of genetic variants characteristic of the disease could enable it to be diagnosed and to improve patient care. In 2017, efforts by the international community made it possible to identify a total of 14 variants (located on the genes WNT4, GREB1, ETAA1, IL1A, KDR, ID4, CDKN2B-AS1, VEZT, FN1, CCDC170, SYNE1, FSHB, and in the chromosomal regions 7p15.2 and 7p12.3). These 14 genes are involved in proliferation and the cell cycle, adhesion and the extracellular matrix, andinflammation, which makes sense in relation to endometriosis. However, each of the variants identified explain only a small part of the genetic variation in endometriosis. In future, the combination of high-risk alleles in a patient might provide a probability of being affected that could be used to diagnose patients and categorize them based on endometriosis type and severity.

The existence of specific epigenetic markers for endometriosis could also theoretically be used for early detection, with endometrial cells presenting specific epigenetic abnormalities that modify expression of the main transcription factors. However, it is not known how the interactions between the defective epigenomic cells and mutated epithelial cell genes contribute to the pathogenesis of endometriosis.

  • The microRNA approach

The full complexity of endometriosis cannot however be understood through genetics alone. Genes only influence phenotype through their expression. This expression is regulated by epigenetic molecular mechanisms. As such, most research focuses on studying the microRNA that could be “markers” for the disease. Several have been identified in patients’ plasma thus far, but with very poor reproducibility from one research team to the next. For example, a study published in 2013[5] identified just four miRNA (miR-199a, miR122, miR145*, and miR-542-3p) as enough to categorize patients, with very few errors. Confirmation of this article’s findings in independent cohorts has however been slow. One possible explanation for this is the fact that extraction of circulating RNA remains very heterogeneous from one study to the next, perhaps due to the technical tools used in extraction. In future, new, more comprehensive approaches could provide more consistent results.

  • The cellular approach: oxidative stress

Several studies have shown increased oxidative stress in the serum of women with endometriosis. Oxidative stress is a highly general mechanism that induces and is caused by inflammation. It would seem logical to find changes linked to oxidative stress in the context of a painful disease like endometriosis. In mouse models, treatment with antioxidants (N-acetylcysteine) has been seen to reduce endometrial lesions.

Research led by a team from the Institut Cochin has also identified several genes linked to glutathione metabolism within the gene cascades that are deregulated in endometriosis lesions. Glutathione is a peptide that plays a key role in detoxification of hydrogen peroxide, a central molecule in oxidative stress. Down-regulation, particularly of the GCLM and GCLC genes crucial to glutathione synthesis, could explain increased oxidative stress in endometriosis lesions.

  • The dysfunctional immune system: a possible approach?

The survival of endometrial cells outside the uterus could be linked to poor function of the immune system causing chronic local inflammation. Studies have shown an increase in some immune cells around endometriosis lesions.

2.2. Treatment: areas of research and latest findings

Changing diagnostic methods: phasing out surgery

Before considering treatment, the first stage is to reduce the diagnosis time for endometriosis, which is currently around 7 to 10 years after onset of the initial symptoms. With this in mind, doctors and researchers are working to develop a diagnostic score, based on a dozen questions, from which doctors will be able to provide a diagnosis with 85-90% reliability. This score may be accompanied if necessary by imaging, which can inform endometriosis diagnosis if carried out and interpreted by trained medical personnel.

Doctors and researchers agree that diagnostic surgery is contraindicated for endometriosis.

The 3 pillars of treatment

Drug therapy, surgery, and assisted reproductive technology (ART) are currently the only 3 methods for treating the symptoms of endometriosis and its potential impact on fertility. In the absence of new treatments, the key is to understand the role played by each component in this therapeutic arsenal, so that they can be used effectively.

Drug therapy is based on blocking ovarian function to bring about artificial menopause via continuous administration of contraceptives. These therapies (the combined pill, estrogen pill, or GnRH agonists) must be personalized and adapted to the needs of the patient. These therapies should be prescribed as the first-line treatment for women who are not seeking to become pregnant, in order to reduce the pain caused by the disease.

For patients who want to conceive, ART and surgery may be considered. ART should be used routinely before all surgical procedures in order to maximize the chance of conceiving a child for couples who want to do so. Surgery must not be used in women who do not want to conceive in whom drug therapy is effective. Endometriosis surgery can be highly invasive and debilitating (removing some parts of the colon, with a high risk of ovarian reserve depletion if ovarian cysts are removed, etc.), and does not prevent the disease from recurring, as it does not treat the cause. Doctors and researchers also agree that women who undergo surgery at a young age have a high risk of their endometriosis lesions recurring, and encounter further difficulties if they decide they want to become pregnant.

All efforts must therefore be made to move away from using surgery as the standard treatment for endometriosis, as has too often been the case in the past.

Some forms of endometriosis – particularly those affecting the ovaries – are now an indication for providing women with access to various fertility preservation techniques.

The role of new technologies: the example of high-intensity focused ultrasound

In Lyon, teams of research clinicians led by Prof. Gil Dubernard (Hospices Civils de Lyon and Inserm unit 1032 LabTAU) have developed an ultrasound-based treatment for bowel endometriosis. When endometriosis infiltrates the rectal wall, it causes debilitating rectal pain that may affect quality of life. After failure of medical treatment, a surgical procedure is often proposed that consists of removing all or part of the rectum and sometimes requires a temporary colostomy (artificial anus).

A phase I clinical trial carried out in 11 patients in 2017 demonstrated that high-intensity focused ultrasound may be a useful alternative to surgery. An ultrasound probe inserted into the rectal passage is able to “desensitize” the lesions within a few minutes. A follow-up trial of 12 patients seeking to confirm these initial results was completed on April 1, 2019. Data analysis is ongoing and will be available shortly.

Meanwhile, in collaboration with the company EDAP TMS (the clinical trial sponsor), the therapeutic ultrasound Inserm laboratory led by Cyril Lafon, LabTAU (Université Claude Bernard Lyon 1/Inserm), is working on optimizing the conditions of ultrasound delivery (insonification) and improving the ergonomics of the probe in order to increase the number of patients eligible for this new treatment.

It is highly likely that this innovative therapy will replace many of the rectal surgeries carried out in this functional disorder that resolves upon menopause.


[1]     Hypothalamic-Pituitary-Ovarian Axis Reactivation by Kisspeptin-10 in Hyperprolactinemic Women With Chronic Amenorrhea.

Millar RP, Sonigo C, Anderson RA, George J, Maione L, Brailly-Tabard S, Chanson P, Binart N, Young J.

[2] Sonigo C, Jankowski S, Yoo O, Trassard O, Bousquet N, Grynberg M, Beau I, Binart N. High-throughput ovarian follicle counting by an innovative deep learning approach. Sci Rep. 2018 Sep 10;8(1):13499. doi: 10.1038/s41598-018-31883-8.



[5] (Wang et al., JCEM, 2013)

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Fertility preservation techniques

Inserm magazine number 36: Fertility: Are our future generations in danger?

Artificial Intelligence Facilitates Chemical Toxicity Evaluation: the Case of Bisphenol S

©Photo by Philipp Katzenberger on Unsplash

A novel IT tool based on artificial intelligence methods has made it possible to identify the toxic effects of bisphenol S – a frequent substitute for bisphenol A in food containers – using existing published data. In more general terms, this tool developed by Inserm researchers led by Karine Audouze at Unit 1124 “Environmental Toxicity, Therapeutic Targets, Cellular Signaling and Biomarkers” (Inserm/Université de Paris), will make it possible to reveal the toxic effects of any chemical substance (or physical agent) provided that it is already present in databases or published studies. The stages of the development and use of this tool are described in Environmental Health Perspectives.

Artificial intelligence can now be used to simultaneously analyze databases and scientific literature in order to evaluate the toxicity of substances for humans. Such “in silico meta-analysis” has been made possible thanks to an IT program designed by Karine Audouze and her colleagues at Inserm JRU-S1124 (Environmental Toxicology, Therapeutic Targets, Cell Signaling and Biomarkers). It was validated by researching the toxicity of bisphenol S, a frequent substitute for bisphenol A – an endocrine disruptor that has already been banned from use in food containers.

In practice, the researchers incorporated various types of biological and chemical data in their IT program, including the 2,000 terms referenced in the AOP-wiki database (AOP: Adverse Outcome Pathways). “This database comprises precise descriptions of the various biological steps (molecules, signaling pathways) leading from molecular disruption to pathological effects, such as obesity, steatosis, cancer, etc. New toxicity processes are added regularly”, states Audouze. In parallel, with bisphenol S having been used to test the program, the authors incorporated the various designations and synonyms of this component that are found in the scientific literature. Thus equipped, the program scanned the abstracts of scientific articles submitted by the authors, searching for those pre-saved terms. “The aim was to establish links between those terms representing the chemical substance and those corresponding to the pathological processes”, clarifies Audouze. To achieve that, the researchers taught their system to read intelligently. This means that the program gives more weight to terms found side by side rather than far apart from each other, to those found in the results and conclusions sections at the end of the abstract rather than in the hypothesis section at beginning and, finally, by quantifying the words spotted. “The system goes beyond a rapid scan to offer genuine automated text analysis”.

In the end, the analysis revealed a correlation between bisphenol S and the risk of obesity, which was then manually verified by the authors. Then, to further increase the performance of their tool, the authors also incorporated the biological data from ToxCast, a US database that references the effects of many chemical and physical agents on various cell types thanks to robotic analysis. “As such, this strategy makes it possible to suggest mechanisms associated with the toxicity discovered by the program”, explains Audouze. This is how the researchers observed that bisphenol S promotes the formation of adipocytes.

“This IT tool can be used to establish a quick overview of the effects of a chemical agent, which is desirable when the latter is suggested as a substitute for an existing substance. It does not provide proof of toxicity as such but serves to rapidly incorporate a large quantity of data and rank the most likely harmful effects, thereby making it possible to design the most pertinent biological and epidemiological studies”, illustrates Audouze.

This tool can now be freely accessed on the GitHub platform. Any researcher wishing to test the toxicity of an agent can use it by developing a dictionary specific to that agent.

This project was funded by the European Human Biomonitoring Initiative, HBM4EU (

The overall annual cost of infections due to bacterial resistance in French hospitals now estimated up to 290 million Euros

Pour la première fois, une équipe de chercheurs de l’université de Versailles Saint-Quentin-en-Yvelines, de l’Inserm et de l’Institut Pasteur (Unité Mixte de Recherche 1181 Biostatistique, biomathématique, pharmacoépidémiologie et maladies infectieuses – B2PHI) est parvenue à estimer le plus précisément possible le nombre de nouveaux cas et le coût économique direct que représentent les infections à bactéries résistantes aux antibiotiques chez les malades hospitalisés, pendant les années 2015 et 2016.

Les résultats de ces travaux menés par Mehdi Touat et Marion Opatowski sous la direction de Laurence Watier en collaboration avec le professeur Christian Brun-Buisson au sein du groupe de recherche dirigé par Didier Guillemot ont été publiés le 3/12/2018 dans la revue Applied Health Economics and Health Policy et le 12/3/2019 dans la revue Epidemiology & Infection.

En 2016, près de 140 000 nouveaux cas d’infection à bactérie résistante ont été identifiés, ce qui représente 12% de toutes les infections bactériennes ayant nécessité une hospitalisation. Les infections urinaires, respiratoires et intra-abdominales en constituent les 2/3. Elles sont dominées par les bactéries E.coli résistantes aux céphalosporines, les staphylocoques dorés résistants à la méthicilline (SARM) et les bactéries pyocyaniques.

Comparativement aux infections à bactéries sensibles aux antibiotiques, les infections à bactéries résistantes entraînent 20% de décès supplémentaires à l’hôpital.

Il a été calculé que le surcoût lié aux infections à bactérie résistante s’élève à 1100 € en moyenne par séjour hospitalier, ce qui conduit à estimer pour l’ensemble de la population un surcout annuel de près de 290 millions d’euros.

Cette étude s’appuie sur le Système National des Données de Santé (SNDS), données d’une rare exhaustivité puisqu’il inclut des informations de diagnostic systématiquement collectées lorsqu’un malade séjourne dans un hôpital français. Les informations auxquelles l’équipe de recherche a eu accès portent sur plus de 10 millions de patients hospitalisés annuellement. Débuté il y a 3 ans, ce travail a été initié grâce au soutien du Ministère de la Santé et en collaboration avec l’Assurance Maladie.

Les algorithmes créés pour ce travail de recherche seront rendus publiques. Ce qui dorénavant permettra de rapidement réaliser les analyses pour les années suivantes et les années à venir.

Hypertension: A New Drug Coming Soon?

Prise de la tension artérielle chez un patient ©Inserm/Depardieu, Michel

Firibastat is the first in a new class of antihypertensive drugs targeting the renin-angiotensin system in the brain. A phase IIa placebo-controlled clinical trial provided initial data on its efficacy in hypertensive patients and was coordinated by Michel Azizi from Inserm/Hôpital Européen Georges-Pompidou AP-HP Clinical Investigation Center 1418 and the Hypertension Department of the same hospital and by Catherine Llorens-Cortes, Inserm Research Director at Unit 1050 “Center for Interdisciplinary Research in Biology” at Collège de France. On the basis of these results, published in The Journal of Hypertension, the phase IIb trial was launched in the USA.

Hypertension is the most common chronic disease in France. Linked to an abnormally high pressure of the blood on the vessel walls, its general lack of symptoms can make it appear harmless. Yet if not brought under control, it constitutes one of the main causes of cardiovascular, cerebrovascular and neurodegenerative complications (myocardial infarction, stroke, Alzheimer’s disease…). Hypertension can be normalized by means of lifestyle measures, either alone or more often than not in combination with medication. However, up to 30% of patients either do not respond – or respond poorly – to the treatments currently available. To remedy this, interventional approaches and new therapeutic targets linked to the pathophysiology of the disease are being studied.

The development of the drug firibastat[1] in the treatment of hypertension continues. It is the first in a new therapeutic class targeting the brain renin-angiotensin system controlled by angiotensin III, a peptide that in various hypertension models exerts a stimulating effect on blood pressure via three mechanisms. It increases the activity of the neurons that favor vasoconstriction, it inhibits the reflex that adjusts the intensity of heart contractions to the blood pressure level and, finally, it contributes to the increased secretion of the anti-diuretic hormone vasopressin in the blood, reducing the volume of urine produced by the kidneys.

Firibastat counters these various mechanisms by specifically inhibiting aminopeptidase A, an enzyme in the brain that produces angiotensin III. This drug, taken orally, becomes active in the brain after crossing the blood-brain barrier. Its safety was already tested in healthy subjects in two phase I clinical trials. The recently-published results of the phase IIa trial confirm the safety data and provide the initial efficacy elements. Enrolled in this trial were 34 patients (73% of whom male) with a daytime ambulatory blood pressure of between 135/85 and 170/105 mmHg. They had an average age of 57 and were not obese (average BMI 26.8 kg/m2). One half of the patients received firibastat for four weeks followed by placebo for another four weeks and the other half received the same treatment but in the reverse order: placebo followed by firibastat.

The results demonstrate better control of systolic blood pressure (SBP) with firibastat after four weeks with an average -4.7 mmHg reduction in SBP versus +0.1 mmHg with placebo. A difference which, however, is not statistically significant. “This can be explained not just by the small number of subjects but also by the fact that they had moderate hypertension, explains Inserm Research Director Catherine Llorens-Cortes. Firibastat is an antihypertensive agent and not a hypotensive agent, meaning that it can act on hypertension but will have no effect on normal blood pressure. “Its efficacy should therefore increase with the severity of the hypertension”, clarifies the researcher. A phenomenon which appeared to be confirmed in this trial because the decrease in ambulatory SBP reached -9.4 mmHg in the event of strong baseline hypertension whereas the benefit was less marked for lower baseline SBPs. The authors also verified the safety of firibastat and observed that it did not interfere with the systemic renin-angiotensin system, controlled by angiotensin II.

“These encouraging findings gave the green light to the phase IIb study which has recently been completed in the USA. It has confirmed the efficacy of firibastat in 254 hypertensive overweight high-cardiovascular-risk patients after two months of treatment, including in African-American patients whose hypertension is most often resistant to the treatments currently available.” clarifies Llorens Cortes.

[1] In partnership with the company Quantum Genomics, and with the support of the French National Research Agency (ANR): ANR RPIB CLINAPAI and LabCom CARDIOBAPAI

ChroMS – the brain as never seen before

©3D brainbow astrocytes

Developed by researchers from École Polytechnique, Sorbonne Université, Inserm and the CNRS, ChroMS is a new microscopy technique bringing together color, 3D and high-resolution imaging, and is nothing short of a revolution in vertebrate brain imaging. The ChroMS technique is described in detail in a recently published article in Nature Communications.

Until now, researchers have had to choose between resolution and volume when performing vertebrate brain imaging. They could either obtain very high resolution over small volumes using three-dimensional electron microscopy or an image of the whole brain at resolutions that are far too low to understand the details.

The main advantage of the ChroMS (Chromatic Multiphoton Serial imaging) technique is that it provides a truly high-resolution virtual view (at the cellular level) of certain parts of the brain that are essential for understanding the development of neuronal circuits. Although the visit is virtual, the data are real. They are obtained from the brains of transgenic mice whose neurons produce fluorescent markers originating from jellyfish or coral. When stimulated by an infrared laser, these markers show up as colors.

This instrument is ideal for making extremely precise, 3D reconstructions of regions of the brain with a volume of a few cubic millimeters, which is a breakthrough with this image quality, and this is the appropriate scale for what we want to observe”, explains Emmanuel Beaurepaire, researcher from the Laboratory for Optics and Biosciences (LOB – a joint research lab between École Polytechnique, the CNRS and Inserm). “Using the current version of our instrument, we can also reconstitute a complete mouse brain, albeit at a lower level of precision”.

We are particularly interested in cell lineage,” states Jean Livet, researcher from the Institut de la Vision (Sorbonne Université, Inserm, CNRS). “In other words, the manner in which the brain develops from neural stem cells: what are the daughter cells from a given stem cell, how can a stem cell mutation influence their development, and how are groups of cells generated by different stem cells organized in relation to one another? The high-volume, color-coded images produced by ChroMS reveal the developmental history of an individual region of the brain”.

ChroMS should enable us to answer questions that neuroscientists have been asking for a long time, such as whether neurons arising from the same stem cell connect to each other preferentially to fulfil a given function, and whether pathologies such as epilepsy could be linked to localized problems affecting certain neural stem cells.

Although the ChroMS technique is ideally suited to the study of highly complex organs such as the brain, it can be used on all organs and should also prove a very effective tool for embryogenesis studies.

(A) Principle of ChroMS microscopy, combining color two-photon excitation by frequency mixing and automated serial slicing of brain tissue. (B) Image acquired with the “whole brain tomography” mode showing the cortex and hippocampus of a Brainbow mouse. (C) 3D reconstruction and view at different scales of a 4.8 mm3 volume of mouse cortex in which astrocytes are marked with fluorescent proteins of different colors. (D) 3D view of color-marked neurons in the mouse cortex. Adapted from: Abdeladim et al, Nat Commun 2019.

Flu Shot: Cutaneous Administration Improves Efficacy

©Photo by Kelly Sikkema on Unsplash

Are there ways to improve the efficacy of flu vaccines? Are there markers that could, at the time of vaccination, predict the quality of the immune response several weeks down the line? Thanks to the work of Inserm Research Director Béhazine Combadière’s team at Unit 1135 “Center for Immunology and Infectious Diseases”, the answer to these two major questions is “yes”.

Their findings were published on April 8, 2019 in JCI.

While flu continues to claim lives every year[1], a vaccine exists to protect the populations. And while this vaccine is the best means of preventing the disease and reducing the risk of severe complications and death, it is not 100 % effective. This is due to the fact that its formulation is determined each year by the WHO several months before the epidemic peak and that it is based only on the probability that such and such a flu strain will be in circulation during the coming winter. Flu viruses are highly unpredictable, and the vaccine formulation must change from one year to the next. However, given that 5 to 6 months are needed to develop it, the vaccine does not always target all of the circulating strains.

The team of Béhazine Combadière, Inserm Research Director at Unit 1135 “Center for Immunology and Infectious Diseases”, has been working for years on the impact of vaccine administration routes on the quality of immune responses. The vaccines are usually administered by the muscular route and are effective in inducing humoral responses (production of antibodies), whereas the other immune response component, the cytotoxic response (production of T cells that directly destroy the infected cells) is poorly-induced by this route of administration.

The team studied the utility of administration via the skin – either by intradermal injection or transcutaneous application (via the hair follicles) – in inducing cytotoxic responses during flu vaccination. This involved conducting a phase I/II clinical trial on 60 people between 18 and 45 years of age in collaboration with the Vaccinology CIC led by Dr. Odile Launay. The study, published in JCI, demonstrates that in some subjects the cutaneous routes induce a cytotoxic response following flu vaccination. “This finding argues in favor of considering this vaccine injection route given that it triggers an immune reaction additional to that obtained with a standard vaccination. These cytotoxic responses would be particularly protective in elderly people following flu vaccination. ” explains Combadière.

In addition to these findings, the team brings new elements to the table concerning the specific imprints left by these injection routes in the body. For this, the researchers studied the gene signature of innate immunity, i.e. the expression of the messenger RNA of the genes in the blood the day after vaccination for each administration route. “Since previous findings showed that each administration route had its own innate response, we expected to have three signatures of innate immunity corresponding to the three administration routes, yet our findings only show two. These two signatures are correlated with the immune response of the individual: those that respond to the vaccine by increasing their humoral response and those that respond by inducing a cytotoxic response. “

Among these signatures, a certain number of biomarkers expressed the day after vaccination are thought to be predictive of the quality of immune response three weeks later. “However, these latest findings require other studies to validate the utility of these biomarkers and their future use”, conclude the researchers.

[1] For the winter of 2018-2019, over 2,000 deaths were attributed to the flu according to French Public Health Agency data.

Cesarean Delivery Linked to Increased Risk of Severe Maternal Complications

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Cesarean delivery is thought to be linked to a greater risk of severe maternal complications – primarily hemorrhagic – than vaginal delivery, especially in women aged 35 and over. This is what a team of researchers from Inserm, Université Paris Descartes, Université Paris Diderot and Université Paris 13 have observed. These new findings, published in Canadian Medical Association Journal (CMAJ), clearly distinguish the risks linked to this procedure from those related to the pathology or clinical context having required it.

There has been a marked increase in cesarean section rates over the last 20 years worldwide. According to the recent results of the 2015 Euro-Peristat report on perinatal health in France and Europe, France is one of the European countries with the lowest cesarean rate, albeit with one in five deliveries concerned.

Various studies have already examined the risks related to this mode of delivery. However, while many of them came to the conclusion of an apparent link between cesarean sections and severe maternal complications (massive hemorrhage, infection, pulmonary embolism, etc.), they did not clearly distinguish between the complications resulting from the condition or clinical context requiring the cesarean from those resulting from surgery itself.

To understand whether cesareans themselves are linked to severe maternal complications, French researchers from the EPOPE team at the Research Center for Epidemiology and Biostatistics Sorbonne Paris Cité – CRESS (Inserm/INRA/Université Paris Descartes/Université Paris Diderot/Université Paris 13), examined a subpopulation of a larger study (EPIMOMS).

In six regions of France, they compared 1444 women who had experienced severe post-birth complications – major hemorrhages for the most part – with 3464 control women who had not experienced such events. The tools used for the analysis took into account the women’s risk level and health condition prior to delivery, in order to best isolate the risks related solely to the cesarean section.

The research team observed an increased risk of severe post-birth complications in women having undergone cesarean section, irrespective of whether it was performed before or during labor. These findings are particularly significant in women aged 35 and over.

Indeed, while severe maternal complications are rare overall (1.5 % of deliveries), the study revealed an almost two-fold (x1.8) probability of occurrence in women with cesarean as opposed to vaginal delivery, rising to three-fold for women aged 35 and over. The researchers hypothesized that this age-related potentiation of the hemorrhagic excess risk is linked to the age-related reduction of the ability of the uterus to contract after birth to halt the physiological bleeding.

According to Inserm research director and study leader Catherine Deneux-Tharaux: “These findings have implications for clinical practice and will be useful when deciding on the mode of delivery; both women and physicians must be informed of this increased risk in order to determine the best mode of delivery, especially in the case of older mothers.”

Narcolepsy: A New Drug to Fight Sleepiness

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How can the quality of life of patients with narcolepsy, the severest sleep disorder in humans, be improved? An international scientific team led by Yves Dauvilliers, a researcher at Inserm and Université de Montpellier, is working on Solriamfetol – a promising new drug that stimulates alertness and improves resistance to sleepiness. The results of the Phase 3 clinical trial published in Annals of Neurology show that when compared with existing treatments, Solriamfetol is not just more effective and long-lasting, but also has fewer side effects.

Narcolepsy is a chronic rare neurological disorder caused by a loss of neurons that synthesize the protein hypocretin. It is characterized by excessive daytime sleepiness and difficulty staying awake. Being the severest sleep disorder in humans, it is an excellent model for studying other pathologies of the same type.

Existing treatments to improve the symptoms of narcolepsy are thin on the ground, inconsistent in their efficacy and sometimes linked to side effects. And they only treat the symptoms, not the root cause. Since research is as yet unable to produce synthetic hypocretin, these treatments make do with compensating the lack of hypocretin: they stimulate alertness by acting primarily on dopamine transporters.

It is on the development of a more effective drug in improving narcolepsy symptoms that is working Yves Dauvilliers, researcher at Inserm and Université de Montpellier in the “Neuropsychiatry: Epidemiological and Clinical Research” laboratory (Inserm/Université de Montpellier), in collaboration with international teams. The research he is leading is centered around Solriamfetol[1], a drug that not only inhibits the transporters of dopamine but also those of norepinephrine – another neurotransmitter involved in the regulation of waking.

In this Phase 3 clinical trial, 240 narcoleptic patients were followed for 12 weeks in order to evaluate the efficacy and safety of Solriamfetol in humans. The tests were performed under double-blind conditions on groups of 60 patients receiving different doses of Solriamfetol or placebo. In addition to patient feedback on the day-to-day changes in their sleepiness, the trial also involved tests in which the patients were required to try to stay awake in an atmosphere conducive to sleep.

The research team observed that those patients receiving a daily dose of 150 mg or 300 mg Solriamfetol managed to fight sleepiness for around 20 minutes versus 10 without treatment, i.e. for twice as long. The currently-prescribed treatments extend this alertness by only 2 to 3 minutes. This efficacy was maintained throughout the 12 weeks of treatment, with few side effects and no need to increase dosage.

“By enabling them to better resist sleepiness, Solriamfetol therefore proves to be highly promising when it comes to improving the quality of life of people with narcolepsy and also in the other disorders linked to sleepiness, such as sleep apnea syndrome – in which it offers the same efficacy”, states Dauvilliers. In order to evaluate its efficacy and safety over time, the researchers have launched a new clinical trial lasting one year.

[1]The study protocol was developed, in collaboration with the authors, by Jazz Pharmaceuticals, which is funding the trial and holds a license to develop and commercialize Solriamfetol