The effect of gut microbiota dysbiosis on patients with preeclampsia

Unraveling the role of the gut microbiome in pregnancy disorders: insights and implications

The gut microbiota is the collective term for the microorganisms that reside in the human gut. In recent years, advances in sequencing technology and bioinformatics gradually revealed the role of gut microbiota in human health. Dramatic changes in the gut microbiota occur during pregnancy due to hormonal and dietary changes, and these changes have been associated with certain gestational diseases such as preeclampsia (PE) and gestational diabetes mellitus (GDM). Modulation of gut microbiota has also been proposed as a potential treatment for these gestational diseases. The present article aims to review current reports on the association between gut microbiota and gestational diseases, explore possible mechanisms, and discuss the potential of probiotics in gestational diseases. Uncovering the link between gut microbiota and gestational diseases could lead to a new therapeutic approach.

Gut microbiota interacting with vitamin D but not anandamide might contribute to the pathogenesis of preeclampsia: a preliminary study

Introduction

Preeclampsia (PE) is a pregnancy-specific multisystem disorder and a leading cause of maternal and perinatal mortality globally. Despite numerous studies highlighting the potential roles of gut microbiota, anandamide (AEA), and Vitamin D (VitD) in PE, none have established them as reliable biomarkers for predicting disease onset. Moreover, their interactions in late-stage pregnancy women remain poorly understood.

Methods

Thirty-four preeclamptic patients (called PE group) and thirty-nine matched healthy late-pregnant women (called LP group) were involved in this case-control study. Fecal samples, which were used to acquire the diversity and composition of gut microbiota, were analyzed by 16S rRNA gene sequencing. Plasma AEA concentrations and serum VitD levels were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively.

Results

In this study, β diversity but not α diversity significantly differed between the LP and PE groups. Compared with the LP group, the relative abundances of Prevotella, Erysipelotrichaceae_UCG-003, and Dorea were increased dramatically in the PE group, whereas the relative abundances of Subdoligranulum, Parabacteroides, Bacteroides were significantly decreased in the PE group. Furthermore, women with PE had a substantially lower plasma level of AEA and a marked decrease in serum VitD compared to normal late-pregnant women. Lastly, although the serum level of AEA was not significantly correlated with VitD or any of the top 6 marker genera, VitD was significantly negatively correlated with the relative abundance of Dorea, a novel finding in this context.

Discussion

The gut microbiota profile of the PE group was significantly different from that of the LP group. Although no significant correlations were identified between the plasma AEA levels and serum VitD levels or any of the top 6 identified marker genera, a significant negative correlation was observed between VitD and Dorea, indicating VitD and gut microbiota have the potential to be combined targets for early diagnosis and management of PE.

Nutraceuticals as Modulators of Molecular Placental Pathways: Their Potential to Prevent and Support the Treatment of Preeclampsia

Preeclampsia (PE) is a serious condition characterized by new-onset hypertension and proteinuria or organ dysfunction after the 20th week of gestation, making it a leading cause of maternal and fetal mortality worldwide. Despite extensive research, significant gaps remain in understanding the mechanisms underlying PE, contributing to the ineffectiveness of current prevention and treatment strategies. Consequently, premature cesarean sections often become the primary intervention to safeguard maternal and fetal health. Emerging evidence indicates that placental insufficiency, driven by molecular disturbances, plays a central role in the development of PE. Additionally, the maternal microbiome may be implicated in the pathomechanism of preeclampsia by secreting metabolites that influence maternal inflammation and oxidative stress, thereby affecting placental health. Given the limitations of pharmaceuticals during pregnancy due to potential risks to fetal development and concerns about teratogenic effects, nutraceuticals may provide safer alternatives. Nutraceuticals are food products or dietary supplements that offer health benefits beyond basic nutrition, including plant extracts or probiotics. Their historical use in traditional medicine has provided valuable insights into their safety and efficacy, including for pregnant women. This review will examine how the adoption of nutraceuticals can enhance dysregulated placental pathways, potentially offering benefits in the prevention and treatment of preeclampsia.

Calorie restriction during gestation impacts maternal and offspring fecal microbiome in mice

Background

Maternal undernutrition is the most common cause of fetal growth restriction (FGR) worldwide. FGR increases morbidity and mortality during infancy, as well as contributes to adult-onset diseases including obesity and type 2 diabetes. The role of the maternal or offspring microbiome in growth outcomes following FGR is not well understood.

Methods

FGR was induced by 30% maternal calorie restriction (CR) during the second half of gestation in C57BL/6 mice. Pup weights were obtained on day of life 0, 1, and 7 and ages 3, 4 and 16 weeks. Fecal pellets were collected from pregnant dams at gestational day 18.5 and from offspring at ages 3 and 4 weeks of age. Bacterial genomic DNA was used for amplification of the V4 variable region of the 16S rRNA gene. Multivariable associations between maternal CR and taxonomic abundance were assessed using the MaAsLin2 package. Associations between microbial taxa and offspring outcomes were performed using distance-based redundancy analysis and Pearson correlations.

Results

FGR pups weighed about 20% less than controls. Beta but not alpha diversity differed between control and CR dam microbiomes. CR dams had lower relative abundance of Turicibacter, Flexispira, and Rikenella, and increased relative abundance of Parabacteroides and Prevotella. Control and FGR offspring microbiota differed by beta diversity at ages 3 and 4 weeks. At 3 weeks, FGR offspring had decreased relative abundance of Akkermansia and Sutterella and increased relative abundance of Anaerostipes and Paraprevotella. At 4 weeks, FGR animals had decreased relative abundance of Allobaculum, Sutterella, Bifidobacterium, and Lactobacillus, among others, and increased relative abundance of Turcibacter, Dorea, and Roseburia. Maternal Helicobacter abundance was positively associated with offspring weight. Akkermansia abundance at age 3 and 4 weeks was negatively associated with adult weight.

Conclusions

We demonstrate gut microbial dysbiosis in pregnant dams and offspring at two timepoints following maternal calorie restriction. Additional research is needed to test for functional roles of the microbiome in offspring growth outcomes.

Scoping Review of Microbiota Dysbiosis and Risk of Preeclampsia

Limited studies have investigated the role of the microbiota in hypertensive disorders of pregnancy (HDP), particularly preeclampsia, which often results in preterm birth. We evaluated 23 studies that explored the relationship between gut, vaginal, oral, or placental microbiotas and HDP. Scopus, ProQuest Health Research Premium Collection, ProQuest Nursing & Allied Health Database, EBSCO, and Ovid were searched for relevant literature. Majority (18) of studies focused on the gut microbiota, and far fewer examined the oral cavity (3), vagina (3), and placenta (1). One study examined the gut, oral, and vaginal microbiotas. The consensus highlights a potential role for microbiota dysbiosis in preeclampsia and HDP. Especially in the third trimester, preeclampsia is associated with gut dysbiosis-deficient in beneficial species of Akkermansia, Bifidobacterium, and Coprococcus but enriched with pathogenic Campylobacterota and Candidatus Saccharibacteria, with low community α-diversity. Similarly, the preeclamptic vaginal and oral microbiotas are enriched with bacterial vaginosis and periodontal disease-associated species, respectively. The trend is also observed in the placenta, which is colonized by gastrointestinal, respiratory tract, and periodontitis-related pathogens. Consequently, a chronic proinflammatory state that adversely impacts placentation is implicated. These observations however require more mechanistic studies to establish the timing of the preceding immune dysfunction and any causality.

The Hidden Relationship between Intestinal Microbiota and Immunological Modifications in Preeclampsia Pathogenesis

Preeclampsia is a multifactorial gestational syndrome characterized by increased blood pressure during pregnancy associated with multiorgan involvement. The impact of this disease on maternal and neonatal health is significant, as it can lead to various fetal comorbidities and contribute to the development of maternal comorbidities later in life. Consistent evidence has shown that the microbiota acts as a regulator of the immune system, and it may, therefore, influence the development of preeclampsia by modulating immune factors. This narrative review aims to investigate the role of the immune system in the pathogenesis of preeclampsia and to summarize the most recent literature on the possible link between preeclampsia and alterations in the intestinal microbiota. To this end, we conducted a literature search, aiming to perform a narrative review, on PubMed and Embase from January 1990 to March 2024, focusing on the latest studies that highlight the main differences in microbial composition between patients with and without preeclampsia, as well as the effects of microbial metabolites on the immune system. From the review of 28 studies assessing the intestinal microbiota in preeclamptic women, preeclampsia could be associated with a state of dysbiosis. Moreover, these patients showed higher plasmatic levels of endotoxin, pro-inflammatory cytokines, and T helper 17 cells; however, the findings on specific microbes and metabolites that could cause immune imbalances in preeclampsia are still preliminary.

Disturbance of gut microbiota aggravates the inflammatory response and damages the vascular endothelial function in patients with preeclampsia

OBJECTIVE

To investigate the influence of intestinal flora imbalance on inflammatory factors in the serum and vascular endothelial functionality in individuals with preeclampsia (PE).

METHODS

From January 2022 to December 2023, a total of 58 individuals with PE (PE group) and 60 healthy controls (CON group) were included in this study; they were matched for age and pre-pregnancy Body Mass Index (BMI). A comparison was made between the two groups in terms of the general data and the number of unique intestinal flora. Additionally, clinical blood measures, serum inflammatory factors, and vascular endothelial function were also assessed and compared between the groups.

RESULTS

Age, gestational age, and pre-pregnancy BMI were similar between the PE and control group. However, diastolic and systolic blood pressure were significantly higher in the PE group. The abundance of Lactobacillus, Bifidobacterium, Enterobacter, and Enterococcus. Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were considerably higher in the PE group compared to the CON group, but Interleukin-4 (IL-4) was noticeably lower, and the amount of White blood cells (WBC), neutrophil count (N) and lymphocyte count (L) in the PE group were significantly higher than those in the CON group. In the PE group, serum vascular endothelin (ET) and soluble endoglin (sEng) were higher than in the CON group, vascular endothelial growth factor (VEGF) and nitric oxide (NO) levels were considerably lower than in the CON group, and the levels of TC, TG, LDL-C and HDL-C were significantly higher in the PE group than in the CON group. The presence of Lactobacillus and Bifidobacterium was inversely associated with levels of TNF-α, IL-6, Interleukin-10 (IL-10), ET, and sEng, and positively associated with levels of IL-4, VEGF, and NO. Nevertheless, there was a positive correlation between the abundance of Enterobacterium and Enterococcus with the levels of TNF-α, IL-6, IL-10, ET, and sEng. Conversely, there was a negative correlation between the abundance of Enterobacterium and Enterococcus and the levels of IL-4, VEGF, and NO.

CONCLUSION

Patients with PE exhibited dysbiosis of intestinal flora, characterized by altered gut microbiota diversity, increased serum pro-inflammatory factors, and impaired vascular endothelial function.

Preeclampsia: A comprehensive review

Preeclampsia (PE) is a life-threatening disease of pregnancy and a prominent cause of neonatal and maternal mortality and morbidity. PE affects approximately 5-10% of pregnancies worldwide, posing significant risks to perinatal and maternal health. It is characterized by a variety of interconnected pathological cascades contributing to the stimulation of intravascular inflammation, oxidative stress (OS), endothelial cell activation, and syncytiotrophoblast stress that converge on a common pathway, ultimately resulting in disease progression. The present study was designed and executed to review the existing scientific literature, specifically focusing on the etiology (gestational diabetes mellitus and maternal obesity, insulin resistance, metabolic syndrome, maternal infection, periodontal disease, altered microbiome, and genetics), clinical presentations (hypertension, blood disorders, proteinuria, hepatic dysfunction, renal dysfunction, pulmonary edema, cardiac dysfunction, fetal growth restrictions, and eclampsia), therapeutic clinical biomarkers (creatinine, albuminuria, and cystatin C) along with their associations and mechanisms in PE. In addition, this study provides insights into the potential of nanomedicines for targeting these mechanisms for PE management and treatment. Inflammation, OS, proteinuria, and an altered microbiome are prominent biomarkers associated with progression and PE-related pathogenesis. Understanding the molecular mechanisms, exploring suitable markers, targeted interventions, comprehensive screening, and holistic strategies are critical to decreasing the incidence of PE and promoting maternal-fetal well-being. The present study comprehensively reviewed the etiology, clinical presentations, therapeutic biomarkers, and preventive potential of nanomedicines in the treatment and management of PE.

Maternal gut microbiota in the health of mothers and offspring: from the perspective of immunology

Due to the physiological alteration during pregnancy, maternal gut microbiota changes following the metabolic processes. Recent studies have revealed that maternal gut microbiota is closely associated with the immune microenvironment in utero during pregnancy and plays a vital role in specific pregnancy complications, including preeclampsia, gestational diabetes, preterm birth and recurrent miscarriages. Some other evidence has also shown that aberrant maternal gut microbiota increases the risk of various diseases in the offspring, such as allergic and neurodevelopmental disorders, through the immune alignment between mother and fetus and the possible intrauterine microbiota. Probiotics and the high-fiber diet are effective inventions to prevent mothers and fetuses from diseases. In this review, we summarize the role of maternal gut microbiota in the development of pregnancy complications and the health condition of future generations from the perspective of immunology, which may provide new therapeutic strategies for the health management of mothers and offspring.

Host-gut microbiota interactions during pregnancy

Mammalian pregnancy is characterized by a well-known suite of physiological changes that support fetal growth and development, thereby positively affecting both maternal and offspring fitness. However, mothers also experience trade-offs between current and future maternal reproductive success, and maternal responses to these trade-offs can result in mother-offspring fitness conflicts. Knowledge of the mechanisms through which these trade-offs operate, as well as the contexts in which they operate, is critical for understanding the evolution of reproduction. Historically, hormonal changes during pregnancy have been thought to play a pivotal role in these conflicts since they directly and indirectly influence maternal metabolism, immunity, fetal growth and other aspects of offspring development. However, recent research suggests that gut microbiota may also play an important role. Here, we create a foundation for exploring this role by constructing a mechanistic model linking changes in maternal hormones, immunity and metabolism during pregnancy to changes in the gut microbiota. We posit that marked changes in hormones alter maternal gut microbiome composition and function both directly and indirectly via impacts on the immune system. The gut microbiota then feeds back to influence maternal immunity and metabolism. We posit that these dynamics are likely to be involved in mediating maternal and offspring fitness as well as trade-offs in different aspects of maternal and offspring health and fitness during pregnancy. We also predict that the interactions we describe are likely to vary across populations in response to maternal environments. Moving forward, empirical studies that combine microbial functional data and maternal physiological data with health and fitness outcomes for both mothers and infants will allow us to test the evolutionary and fitness implications of the gestational microbiota, enriching our understanding of the ecology and evolution of reproductive physiology.

Research progress on the correlation between gut microbiota and preeclampsia: microbiome changes, mechanisms and treatments

Preeclampsia is a specific disease during pregnancy and is a significant factor in the increased mortality in perinatal women. Gut microbiota, an intricate and abundant microbial community in the digestive tract, is crucial for host metabolism, immunity, and nutrient absorption. The onset and progression of preeclampsia are closely correlated with the changes in maternal gut microbiota. Research purpose was to compile the existing bits of present scientific data and to close the gap in the knowledge of changes in gut microbiota in preeclampsia and their association with preeclampsia. We searched studies from two electronic databases (PubMed and Web of Science) included from 2014 to 2023. This review is divided into three parts. In the first part, the author elaborates longitudinal differences of maternal gut microbiota during different gestation periods. In the second part, we discuss that gut microbiota can lead to the occurrence of preeclampsia by systemic immune response, influencing the release of active peptides, short-chain fatty acids, trimethylamine-N-oxide (TMAO) and other metabolites, vascular factors and Microorganism-immune axis. In the third part, we proposed that a high-fiber diet combined with drugs and microecological regulators may be therapeutic in enhancing or preventing the emergence and evolution of preeclampsia, which needs further exploration. Although the pathogenesis of preeclampsia is still nebulous and there is no clear and valid clinical treatment, our study provides new ideas for the pathogenesis, prevention and treatment of preeclampsia.

The role of short-chain fatty acids produced by gut microbiota in the regulation of pre-eclampsia onset

Background

Preeclampsia (PE) is a common pregnancy-related disorder characterized by disrupted maternal-fetal immune tolerance, involving diffuse inflammatory responses and vascular endothelial damage. Alterations in the gut microbiota (GM) during pregnancy can affect intestinal barrier function and immune balance.

Aims and purpose

This comprehensive review aims to investigate the potential role of short-chain fatty acids (SCFAs), essential metabolites produced by the GM, in the development of PE. The purpose is to examine their impact on colonic peripheral regulatory T (Treg) cells, the pathogenic potential of antigen-specific helper T (Th) cells, and the inflammatory pathways associated with immune homeostasis.

Key insights

An increasing body of evidence suggests that dysbiosis in the GM can lead to alterations in SCFA levels, which may significantly contribute to the development of PE. SCFAs enhance the number and function of colonic Treg cells, mitigate the pathogenic potential of GM-specific Th cells, and inhibit inflammatory progression, thereby maintaining immune homeostasis. These insights highlight the potential significance of GM dysregulation and SCFAs produced by GM in the pathogenesis of PE. While the exact causes of PE remain elusive, and definitive clinical treatments are lacking, the GM and SCFAs present promising avenues for future clinical applications related to PE, offering a novel approach for prophylaxis and therapy.

Microbiota-associated mechanisms underlying sexual dimorphism in hypertension

Consistent research over the last 20 years has shown that there are clear sex differences in the pathogenesis of hypertension, the leading risk factor for the development of cardiovascular diseases. More recently, there is evidence in both humans and experimental animal models that causally implicates the gut microbiota in hypertension. It therefore follows that sex differences in the gut microbiota may mediate the extent of disease between sexes. This new field is rapidly changing and advancing, and the purpose of this review is to cover the most up-to-date evidence regarding the sexual dimorphism of the gut microbiota and its potential influence on the differential manifestation of hypertension in males versus females. Emphasis will be placed on the mechanisms thought to contribute to these sex differences in both the gut microbiota and hypertension, including sex steroid hormones, gut-derived metabolites, the immune system, and pregnancy.