Maternal exposure of mice to glyphosate induces depression- and anxiety-like behavior in the offspring via alterations of the gut-brain axis

Association between glyphosate exposure and cardiovascular health using "Life's Essential 8" metrics in US adults

BACKGROUND

Glyphosate, as one of the most widely used herbicides worldwide, has been reclassified as a potential carcinogen and linked to multiple health problems. Recent data from animal experiments have proved its potential cardiovascular toxicity. However, whether glyphosate exposure influences human cardiovascular health at the population levels remains unknown. This study aims to elucidate the correlation between glyphosate exposure and Cardiovascular Health (CVH) by utilizing comprehensive Life's Essential 8 (LE8) metrics.

METHODS

Data from 2842 participants, approximating 155.24 million U.S. adults, from 2013 to 2018 in National Health and Nutrition Examination Survey were analyzed. The association between natural logarithm (ln)-transformed glyphosate exposure in urine and CVH was examined using weighted linear regression and restricted cubic spline (RCS) models. Mediation analysis was used to determine potential mediators correlated with glyphosate and CVH. Further subgroup analysis and sensitive analysis were conducted to confirm the results.

RESULTS

In fully adjusted models, the total CVH score decreased by 1.33 points for every unit increase in continuous ln-transformed glyphosate [β = -1.33, 95 % confidence interval (CI) (-2.25, -0.41)]. There was a negative correlation between the total CVH score and the lowest quantiles of ln-transformed glyphosate (Q1), Q2, Q3, and Q4 with p for trend < 0.05. A non-linear relationship between glyphosate and total CVH emerged (p for non-linear<0.001, p for overall = 0.003), and no safe threshold of glyphosate was observed. Serum insulin was an important mediator in the adverse effects of glyphosate on CVH with an 18.73 % mediation proportion. Moreover, higher serum insulin levels and higher homeostasis model assessment of insulin resistance were associated with higher glyphosate exposure but negatively correlated with total CVH score.

CONCLUSIONS

Glyphosate exposure may pose a risk to cardiovascular health at the population levels, with elevated serum insulin levels acting as a crucial mediating element. Further studies are required to investigate the safe threshold and underlying mechanism of glyphosate impairment.

Maternal exposure to glyphosate increased the risk of adverse neurodevelopmental outcomes in rodent offspring: A systematic review

The potential neurotoxicity of environmental contaminants, such as pesticides, is implicated in the etiology of neurodevelopmental disorders, particularly given the heightened vulnerability of the developing brain. Among these contaminants, glyphosate, a widely used herbicide, has been linked to alterations in neurodevelopment, though its precise neurotoxic mechanisms are not fully elucidated. In this context, our systematic review evaluates the impact of maternal exposure to glyphosate alone (GLY) or glyphosate-based-herbicide (GBH) on neurodevelopmental and behavioral outcomes in rodent offspring. This assessment encompasses a comprehensive examination of behavioral, biochemical, morphological, and genetic alterations resulting from perinatal glyphosate exposure. The Systematic review protocol was registered in the platform Open Science Framework (OSF) following the guidelines of the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE). Our analysis demonstrate that glyphosate disrupts redox signaling, metabolic pathways, and neurotransmitter systems, thereby affecting brain architecture and function across genders and developmental stages in rodents. The results of this review elucidate the extensive neurochemical and behavioral disruptions attributed to glyphosate, highlighting the critical need for advanced neurodevelopmental risk assessment methodologies. Such refined evaluations are vital to inform targeted prevention and intervention strategies in the context of environmental neurotoxicants.

Evidence from mendelian randomization identifies several causal relationships between primary membranous nephropathy and gut microbiota

BACKGROUND

Research has showcased a correlation between disruptions in gut microbiota and primary membranous nephropathy (pMN), giving rise to the concept of the 'gut-kidney axis'. However, the precise relationship between gut microbiota and pMN remains elusive. Hence, this study endeavors to investigate whether a causal relationship exists between gut microbiota and pMN utilizing Mendelian randomization (MR) analysis.

METHODS

The primary method employed for MR analysis is the inverse variance weighting method, supplemented by MR-Egger and the weighted median method, to infer causality. This approach was validated within the pMN cohort across two distinct populations.

RESULTS

At the species level, the abundance of Bifidobacterium bifidum and Alistipes indistinctus was negatively correlated with the risk of pMN. Conversely, pMN was positively associated with Bacilli abundance at the class level, Lachnospiraceae abundance at the family level, and Dialister abundance at the genus level. Specifically, at the species level, pMN was positively correlated with the abundance of Ruminococcus lactaris, Dialister invisus, and Coprococcus_sp_ART55_1.

CONCLUSION

These findings lay the groundwork for future research exploring the interplay between pMN and the gut microbiota, with substantial implications for the prevention and treatment of pMN and its associated complications.

Melatonin Ameliorates Depressive-Like Behaviors in Ovariectomized Mice by Improving Tryptophan Metabolism via Inhibition of Gut Microbe Alistipes Inops

Melatonin (N-acetyl-5-methoxytryptamine) is reported to improve mood disorders in perimenopausal women and gut microbiome composition is altered during menopausal period. The possible role of microbiome in the treatment effect of melatonin on menopausal depression remains unknown. Here, it is shown that melatonin treatment reverses the gut microbiota dysbiosis and depressive-like behaviors in ovariectomy (OVX) operated mice. This effect of melatonin is prevented by antibiotic cocktails (ABX) treatment. Transferring microbiota harvested from adolescent female mice to OVX-operated mice is sufficient to ameliorate depressive-like behaviors. Conversely, microbiota transplantation from OVX-operated mice or melatonin-treated OVX-operated mice to naïve recipient mice exhibits similar phenotypes to donors. The colonization of Alistipes Inops, which is abundant in OVX-operated mice, confers the recipient with depressive-like behaviors. Further investigation indicates that the expansion of Alistipes Inops induced by OVX leads to the degradation of intestinal tryptophan, which destroys systemic tryptophan availability. Melatonin supplementation restores systemic tryptophan metabolic disorders by suppressing the growth of Alistipes Inops, which ameliorates depressive-like behaviors. These results highlight the previously unrecognized role of Alistipes Inops in the modulation of OVX-induced behavioral disorders and suggest that the application of melatonin to inhibit Alistipes Inops may serve as a potential strategy for preventing menopausal depressive symptoms.

The Potential Impact of the Gut Microbiota on Neonatal Brain Development and Adverse Health Outcomes

Over the past decade, microbiome research has significantly expanded in both scope and volume, leading to the development of new models and treatments targeting the gut-brain axis to mitigate the effects of various disorders. Related research suggests that interventions during the critical period from birth to three years old may yield the greatest benefits. Investigating the substantial link between the gut and brain during this crucial developmental phase raises fundamental issues about the role of microorganisms in human health and brain development. This underscores the importance of focusing on the prevention rather than the treatment of neurodevelopmental and neuropsychiatric disorders. The present review examines the gut microbiota from birth to age 3, with a particular focus on its potential relationship with neurodevelopment. This review emphasizes the immunological mechanisms underlying this relationship. Additionally, the study investigates the impact of the microbiome on cognitive development and neurobehavioral issues such as anxiety and autism. Importantly, it highlights the need to integrate mechanistic studies of animal models with epidemiological research across diverse cultures to better understand the role of a healthy microbiome in early life and the implications of dysbiosis. Furthermore, this review summarizes factors contributing to the transmission of gut microbiome-targeted therapies and their effects on neurodevelopment. Recent studies on environmental toxins known to impact neurodevelopment are also reviewed, exploring whether the microbiota may mitigate or modulate these effects.

Continuous low-level dietary exposure to glyphosate elicits dose and sex-dependent synaptic and microglial adaptations in the rodent brain

Prolonged exposure to low levels of dietary contaminants is a context in modern life that could alter organ physiology gradually. Here, we aimed to investigate the impact of continuous exposure to acceptable daily intake (ADI) and non-observable adverse effect level (NOAEL) of glyphosate from gestation to adulthood using C57BL/6J mice and incorporating these levels into their food pellets. From adulthood, we analyzed neurophysiological and neuro-glia cellular adaptations in male and female animals. Using ex-vivo hippocampal slice electrophysiology, we found a reduced efficacy of Schaffer collateral-to-CA1 excitatory synapses in glyphosate-exposed dietary conditions, with ADI and NOAEL dose-dependent effects. Short-term facilitation of excitatory synaptic transmission was specifically increased in NOAEL conditions, with a predominant influence in males, suggesting a reduced probability of neurotransmitter release. Long-term synaptic potentiation (LTP) was decreased in NOAEL-exposed mice. Next, we explore whether these neurophysiological modifications are associated with neuro-glia changes in the somatosensory cortex and hippocampus. High-resolution confocal microscopy analyses unveil a dose-dependent increased density of excitatory Vglut1+ Homer1+ synapses. Microglial Iba1+ cells displayed a shortening of their ramifications, a sign of cellular reactivity that was more pronounced in males at NOAEL levels. The morphology of GFAP+ astrocytes was generally not modified. Finally, we asked whether mouse-specific cross-correlations exist among all data sets generated. This examination included the novel object recognition (NOR) test performed before ex vivo functional and immunohistochemical examinations. We report a negative linear regression between the number of synapses and NOR or LTP maintenance when plotting ADI and NOAEL datasets. These results outline synaptic and microglial cell adaptations resulting from prenatal and continuous dietary low levels of glyphosate, discernible in, but not limited to, adult males exposed to the NOAEL. We discuss the potential significance of these findings to real-world consumer situations and long-term brain resilience.

Microbiota-Induced Epigenetic Alterations in Depressive Disorders Are Targets for Nutritional and Probiotic Therapies

Major depressive disorder (MDD) is a complex disorder and a leading cause of disability in 280 million people worldwide. Many environmental factors, such as microbes, drugs, and diet, are involved in the pathogenesis of depressive disorders. However, the underlying mechanisms of depression are complex and include the interaction of genetics with epigenetics and the host immune system. Modifications of the gut microbiome and its metabolites influence stress-related responses and social behavior in patients with depressive disorders by modulating the maturation of immune cells and neurogenesis in the brain mediated by epigenetic modifications. Here, we discuss the potential roles of a leaky gut in the development of depressive disorders via changes in gut microbiota-derived metabolites with epigenetic effects. Next, we will deliberate how altering the gut microbiome composition contributes to the development of depressive disorders via epigenetic alterations. In particular, we focus on how microbiota-derived metabolites such as butyrate as an epigenetic modifier, probiotics, maternal diet, polyphenols, drugs (e.g., antipsychotics, antidepressants, and antibiotics), and fecal microbiota transplantation could positively alleviate depressive-like behaviors by modulating the epigenetic landscape. Finally, we will discuss challenges associated with recent therapeutic approaches for depressive disorders via microbiome-related epigenetic shifts, as well as opportunities to tackle such problems.