The gut microbiome in subclinical atherosclerosis: a population-based multi-phenotype analysis

Molecular Mechanisms and Emerging Precision Therapeutics in the Gut Microbiota-Cardiovascular Axis

A microbiome in the gut plays a significant role in cardiovascular health and disease. Dysbiosis is an imbalance in the gut microbiome, leading to multiple cardiovascular diseases (CVD) such as atherosclerosis, hypertension, and heart failure. Gut microbe-derived metabolites such as trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFAs) are important mediators of the gut-heart axis. Evaluation of the relationship between the gut microbiome and host biomarkers with CVD requires the integration of metagenomics and metabolomics with meta-omics approaches. The literature review found that microbes and metabolic signatures are associated with the risk and progression of CVD. The development of precision therapeutic approaches for targeting gut microbiota includes preventing adverse microbial effects using probiotics, prebiotics, and the drug-as-bug approach to inhibit harmful metabolites of microbiomes, and fecal microbiota transplantation (FMT). However, the implication and practice of these findings in clinical settings face challenges due to the heterogeneity of study designs, difficulty in the determination of causality, and the impact of confounding factors such as diet, medication, and potential inter-individual gut microbiome variability. Future researchers are recommended to conduct longitudinal studies to further establish both gut microbiome associations with CVD and develop successful precision therapeutics approaches based on the microbiome for the treatment of CVD.

Targeting gut microbiota to regulate the adaptive immune response in atherosclerosis

Atherosclerosis, the leading cause of death worldwide, is a chronic inflammatory disease leading to the accumulation of lipid-rich plaques in the intima of large and medium-sized arteries. Accumulating evidence indicates the important regulatory role of the adaptive immune system in atherosclerosis during all stages of the disease. The gut microbiome has also become a key regulator of atherosclerosis and immunomodulation. Whilst existing research extensively explores the impact of the microbiome on the innate immune system, only a handful of studies have explored the regulatory capacity of the microbiome on the adaptive immune system to modulate atherogenesis. Building on these concepts and the pitfalls on the gut microbiota and adaptive immune response interaction, this review explores potential strategies to therapeutically target the microbiome, including the use of prebiotics and vaccinations, which could influence the adaptive immune response and consequently plaque composition and development.

Gut Microbiome and Carotid Artery Intima-Media Thickness: A Narrative Review of the Current Scenario

Up to the last update, the gut microbiome (GM) had been associated with a different physiologic host process, including those affecting cardiovascular health. The carotid intima-media thickness (IMT) is an indicator of atherosclerosis and cardiovascular risk. The GM influence on atherosclerosis progression has garnered growing attention in recent years but the consensus in subclinical atherosclerosis remains elusive. The aim of this narrative review is to investigate the connection between the GM and carotid IMT, encompassing mechanisms like the microbiome impact on metabolite production, and systemic inflammation, and its effects on endothelial function. The literature analysis revealed that the GM appears to exert an influence on carotid IMT development, likely through mechanisms involving metabolites' production, systemic inflammation, and endothelial function modulation. Additional research, however, is needed to finely elucidate the relationship between the GM and atherosclerosis. Specifically, more extensive studies are required to pinpoint individuals at the highest risk of developing atherosclerosis based on their GM composition. This will facilitate the enhancement and optimization of cardiovascular disease prevention strategies and enable the treatments' customization for each patient. Further investigations are required to refine patient outcomes in the context of probiotics and other interventions aimed at improving microbiome composition and function.

Mediation effect of gut microbiota on the relationship between physical activity and carotid plaque

Background

Physical activity has been shown to have an effect on Carotid plaque (CP) which is a predictor of Cardiovascular disease (CVD). Studies have shown that physical activity can alter the composition of gut microbiota, whether its influence on CP was mediated by gut microbiota has yet to be proved.

Methods

We conducted a case-control study involving 30 CP patients and 31 controls. Logistic regression was used to analyze the association between CP and physical activity. LefSe was used to explore the association between gut microbiota and physical activity as well as CP, and PhyloMed was used to examine the mediating effect of gut microbiota in the association between physical activity and CP.

Results

After adjusting for potential confounders, adequate physical activity showed a significant association with a decreased risk of CP (ORadj: 0.25, 95%CI: 0.06, 0.97). CP was associated with enrichment in the order Bacteroidales within the phylum Bacteroidetes and the predominant microbiota in individuals without plaque was the order Clostridiales (LDA scores >3). Individuals with adequate physical activity had a higher abundance of the order Clostridiales, while the order Bacteroidetes was enriched in individuals with inadequate physical activity (LDA scores >3). The PhyloMed revealed a significant mediation effect of gut microbiota in the association between physical activity and CP (p = 0.03).

Conclusion

Adequate physical activity was significantly associated with a decreased risk of CP, and this association was mediated by an increase in the abundance of gut microbiota in the order Clostridiales.

Two cosmoses, one universe: a narrative review exploring the gut microbiome's role in the effect of urban risk factors on vascular ageing

In the face of rising global urbanisation, understanding how the associated environment and lifestyle impact public health is a cornerstone for prevention, research, and clinical practice. Cardiovascular disease is the leading cause of morbidity and mortality worldwide, with urban risk factors contributing greatly to its burden. The current narrative review adopts an exposome approach to explore the effect of urban-associated physical-chemical factors (such as air pollution) and lifestyle on cardiovascular health and ageing. In addition, we provide new insights into how these urban-related factors alter the gut microbiome, which has been associated with an increased risk of cardiovascular disease. We focus on vascular ageing, before disease onset, to promote preventative research and practice. We also discuss how urban ecosystems and social factors may interact with these pathways and provide suggestions for future research, precision prevention and management of vascular ageing. Most importantly, future research and decision-making would benefit from adopting an exposome approach and acknowledging the diverse and boundless universe of the microbiome.

Oligella spp.: A systematic review on an uncommon urinary pathogen

BACKGROUND

Oligella is an uncommon Gram-negative coccobacillus that was first thought to belong to the urogenital tract. The genus Oligella comprises two species that were recovered from various samples worldwide.

METHODS

We perform a systematic review focusing on Oligella microbiological characteristics, habitat, role in Human microbiome and infection, and antimicrobial susceptibility.

RESULTS

In humans, Oligella is mainly found as part of the microbiome of individuals with predisposing conditions. Oligella were also associated with invasive infections in patients with underlying diseases. Nevertheless, their prevalence remains to determine. Oligella culture requires up to 48 h on agar media in vitro, while urinary samples are usually incubated for 24 h. Consequently, microbiologists should be prompt to prolong the incubation of agar media when the direct examination showed Gram-negative coccobacilli. Oligella is accurately identified using MALDI-TOF mass spectrometry, but biochemical methods often provided inconsistent results. Specific guidelines for antimicrobial susceptibility testing of Oligella lack but the incubation could require up to 48 h of incubation. In contrast to O. urethralis, which is susceptible to third-generation cephalosporin, O. ureolytica is likely resistant to numerous antimicrobials. Genectic determinants of resistance were identified for beta-lactams and aminoglycosides.

CONCLUSION

Oligella is an uncommon pathogen that can be underrecognized. Microbiologists should be prompt to prolong the incubation of agar media plated with urines when the direct examination showed Gram-negative coccobacilli. Carbapenems should probably be given for the empirical treatment.

Maternal Exposure to Endocrine-Disrupting Chemicals: Analysis of Their Impact on Infant Gut Microbiota Composition

Endocrine disruptors (EDCs) are chemicals that interfere with the endocrine system. EDC exposure may contribute to the development of obesity, type 2 diabetes, and cardiovascular diseases by impacting the composition of an infant's gut microbiota during the first 1000 days of life. To explore the relationship between maternal urinary levels of Bisphenol-A and phthalates (UHPLC-MS/MS), and the composition of the infant gut microbiota (16S rDNA) at age 12 months (T3) and, retrospectively, at birth (T0), 1 month (T1), and 6 months (T2), stool samples from 20 infants breastfed at least once a day were analyzed. Metataxonomic bacteria relative abundances were correlated with EDC values. Based on median Bisphenol-A levels, infants were assigned to the over-exposed group (O, n = 8) and the low-exposed group (B, n = 12). The B-group exhibited higher gut colonization of the Ruminococcus torques group genus and the O-group showed higher abundances of Erysipelatoclostridium and Bifidobacterium breve. Additionally, infants were stratified as high-risk (HR, n = 12) or low-risk (LR, n = 8) exposure to phthalates, based on the presence of at least three phthalates with concentrations exceeding the cohort median values; no differences were observed in gut microbiota composition. A retrospective analysis of gut microbiota (T0-T2) revealed a disparity in β-diversity between the O-group and the B-group. Considering T0-T3, the Linear Discriminant Effect Size indicated differences in certain microbes between the O-group vs. the B-group and the HR-group vs. the LR-group. Our findings support the potential role of microbial communities as biomarkers for high EDC exposure levels. Nevertheless, further investigations are required to deeply investigate this issue.

A new perspective in intestinal microecology: lifting the veil of exercise regulation of cardiometabolic diseases

Cardiometabolic diseases (CMDs), encompassing cardiovascular and metabolic dysfunctions, characterized by insulin resistance, dyslipidemia, hepatic steatosis, and inflammation, have been identified with boosting morbidity and mortality due to the dearth of efficacious therapeutic interventions. In recent years, studies have shown that variations in gut microbiota and its own metabolites can influence the occurrence of CMDs. Intriguingly, the composition and function of the gut microbiota are susceptible to exercise patterns, thus affecting inflammatory, immune, and metabolic responses within the host. In this review, we introduce the key mechanisms of intestinal microecology involved in the onset and development of CMDs, discuss the relationship between exercise and intestinal microecology, and then analyze the role of intestinal microecology in the beneficial effects of exercise on CMDs, aiming at elucidating the gut-heart axis mechanisms of exercise mediated protective effect on CMDs, building avenues for the application of exercise in the management of CMDs.

Wastewater-based epidemiology for tracking bacterial diversity and antibiotic resistance in COVID-19 isolation hospitals in Qatar

BACKGROUND

Hospitals are hotspots for antimicrobial resistance genes (ARGs), and play a significant role in their emergence and spread. Large numbers of ARGs will be ejected from hospitals via wastewater systems. Wastewater-based epidemiology has been consolidated as a tool to provide real-time information, and represents a promising approach to understanding the prevalence of bacteria and ARGs at community level.

AIMS

To determine bacterial diversity and identify ARG profiles in hospital wastewater pathogens obtained from coronavirus disease 2019 (COVID-19) isolation hospitals compared with non-COVID-19 facilities during the pandemic.

METHODS

Wastewater samples were obtained from four hospitals: three assigned to patients with COVID-19 patients and one assigned to non-COVID-19 patients. A microbial DNA quantitative polymerase chain reaction was used to determine bacterial diversity and ARGs.

FINDINGS

The assay recorded 27 different bacterial species in the samples, belonging to the following phyla: Firmicutes (44.4%), Proteobacteria (33.3%), Actinobacteria (11%), Bacteroidetes (7.4%) and Verrucomicrobiota (3.7%). In addition, 61 ARGs were detected in total. The highest number of ARGs was observed for the Hazem Mebaireek General Hospital (HMGH) COVID-19 patient site (88.5%), and the lowest number of ARGs was found for the HMGH non-patient site (24.1%).

CONCLUSION

The emergence of contaminants in sewage water, such as ARGs and high pathogen levels, poses a potential risk to public health and the aquatic ecosystem.

Gut microbiota, circulating inflammatory markers and metabolites, and carotid artery atherosclerosis in HIV infection

BACKGROUND

Alterations in gut microbiota have been implicated in HIV infection and cardiovascular disease. However, how gut microbial alterations relate to host inflammation and metabolite profiles, and their relationships with atherosclerosis, have not been well-studied, especially in the context of HIV infection. Here, we examined associations of gut microbial species and functional components measured by shotgun metagenomics with carotid artery plaque assessed by B-mode carotid artery ultrasound in 320 women with or at high risk of HIV (65% HIV +) from the Women's Interagency HIV Study. We further integrated plaque-associated microbial features with serum proteomics (74 inflammatory markers measured by the proximity extension assay) and plasma metabolomics (378 metabolites measured by liquid chromatography tandem mass spectrometry) in relation to carotid artery plaque in up to 433 women.

RESULTS

Fusobacterium nucleatum, a potentially pathogenic bacteria, was positively associated with carotid artery plaque, while five microbial species (Roseburia hominis, Roseburia inulinivorans, Johnsonella ignava, Odoribacter splanchnicus, Clostridium saccharolyticum) were inversely associated with plaque. Results were consistent between women with and without HIV. Fusobacterium nucleatum was positively associated with several serum proteomic inflammatory markers (e.g., CXCL9), and the other plaque-related species were inversely associated with proteomic inflammatory markers (e.g., CX3CL1). These microbial-associated proteomic inflammatory markers were also positively associated with plaque. Associations between bacterial species (especially Fusobacterium nucleatum) and plaque were attenuated after further adjustment for proteomic inflammatory markers. Plaque-associated species were correlated with several plasma metabolites, including the microbial metabolite imidazole-propionate (ImP), which was positively associated with plaque and several pro-inflammatory markers. Further analysis identified additional bacterial species and bacterial hutH gene (encoding enzyme histidine ammonia-lyase in ImP production) associated with plasma ImP levels. A gut microbiota score based on these ImP-associated species was positively associated with plaque and several pro-inflammatory markers.

CONCLUSION

Among women living with or at risk of HIV, we identified several gut bacterial species and a microbial metabolite ImP associated with carotid artery atherosclerosis, which might be related to host immune activation and inflammation. Video Abstract.

Metagenomic association analysis of cognitive impairment in community-dwelling older adults

The gut microbiota is reportedly involved in neurodegenerative disorders, and exploration of differences in the gut microbiota in different cognitive status could provide clues for early detection and intervention in cognitive impairment. Here, we used data from the Taizhou Imaging Study (N = 516), a community-based cohort, to compare the overall structure of the gut microbiota at the species level through metagenomic sequencing, and to explore associations with cognition. Interestingly, bacteria capable of producing short-chain fatty acids (SCFAs), such as Bacteroides massiliensis, Bifidobacterium pseudocatenulatum, Fusicatenibacter saccharivorans and Eggerthella lenta, that can biotransform polyphenols, were positively associated with better cognitive performance (p < 0.05). Although Diallister invisus and Streptococcus gordonii were not obviously related to cognition, the former was dominant in individuals with mild cognitive impairment (MCI), while the later was more abundant in cognitively normal (CN) than MCI groups, and positively associated with cognitive performance (p < 0.05). Functional analysis further supported a potential role of SCFAs and lactic acid in the association between the gut microbiota and cognition. The significant associations persisted after accounting for dietary patterns. Collectively, our results demonstrate an association between the gut microbiota and cognition in the general population, indicating a potential role in cognitive impairment. The findings provide clues for microbiome biomarkers of dementia, and insight for the prevention and treatment of dementia.

Cordyceps militaris polysaccharides modulate gut microbiota and improve metabolic disorders in mice with diet-induced obesity

BACKGROUND

Cordyceps militaris is an edible and medicinal fungus, and its polysaccharides are among its main pharmacological components. They can display immunomodulation, anti-oxidation, anti-inflammation, anti-hypolipidemic, and other functions. The anti-obesity effect of C. militaris polysaccharides (CMP) is not yet fully understood, however.

RESULTS

In this study, a CMP diet intervention was applied over a 4 week period to mice with obesity induced by a high-fat diet (HFD), followed by profiling of obesity-induced dyslipidemia, low-grade inflammation, and gut dysbiosis. The results suggested that CMP could significantly reduce HFD-induced obesity, alleviate obesity-induced hyperlipidemia and insulin resistance, and ameliorate systemic inflammation, showing a promising ability to protect mice from obesity. Further analyses revealed that CMP could regulate obesity-induced gut dysbiosis by restoring the phylogenetic diversity of gut microbiota. It could also increase the relative abundance of short-chain fatty acid (SCFA)-producing bacteria, while down-regulating the level of bacteria that were positively related to the development of obesity. A correlation analysis showed that Helicobacter, Allobaculum, Clostridium XVIII, Parabacteroides, Ligilactobacillus, Faecalibaculum, Adlercreutzia, and Mediterraneibacter were positively related to obese phenotypes.

CONCLUSION

This study highlights the potential of CMP as a prebiotic agent to protect obese individuals from metabolic disorders and gut dysbiosis. © 2022 Society of Chemical Industry.

Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases

Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.

Unique Pakistani gut microbiota highlights population-specific microbiota signatures of type 2 diabetes mellitus

Biogeographic variations in the gut microbiota are pivotal to understanding the global pattern of host-microbiota interactions in prevalent lifestyle-related diseases. Pakistani adults, having an exceptionally high prevalence of type 2 diabetes mellitus (T2D), are one of the most understudied populations in microbiota research to date. The aim of the present study is to examine the gut microbiota across individuals from Pakistan and other populations of non-industrialized and industrialized lifestyles with a focus on T2D. The fecal samples from 94 urban-dwelling Pakistani adults with and without T2D were profiled by bacterial 16S ribosomal RNA gene and fungal internal transcribed spacer (ITS) region amplicon sequencing and eubacterial qPCR, and plasma samples quantified for circulating levels of lipopolysaccharide-binding protein (LBP) and the activation ability of Toll-like receptor (TLR)-signaling. Publicly available datasets generated with comparable molecular methods were retrieved for comparative analysis of the bacterial microbiota. Overall, urbanized Pakistanis' gut microbiota was similar to that of transitional or non-industrialized populations, depleted in Akkermansiaceae and enriched in Prevotellaceae (dominated by the non-Westernized clades of Prevotella copri). The relatively high proportion of Atopobiaceae appeared to be a unique characteristic of the Pakistani gut microbiota. The Pakistanis with T2D had elevated levels of LBP and TLR-signaling in circulation as well as gut microbial signatures atypical of other populations, e.g., increased relative abundance of Libanicoccus/Parolsenella, limiting the inter-population extrapolation of gut microbiota-based classifiers for T2D. Taken together, our findings call for a more global representation of understudied populations to extend the applicability of microbiota-based diagnostics and therapeutics.

Association of gut microbiota composition and their metabolites with subclinical atheromatosis: A systematic review

Study objective

The present systematic review investigates the hypothesis that specific components of the intestinal microbiome and/or their metabolites are associated with early stages of subclinical arterial damage (SAD).

Design

Based on the MOOSE criteria, we conducted a systematic review of the literature (Scopus, Medline) investigating the potential association between gut microbiota and the most widely applied arterial biomarkers of SAD.

Participants

All studies included individuals without established cardiovascular disease, either with or without SAD.

Intervention

No interventions were made.

Main outcome measures

Association between exposure (components/metabolites of microbiota) and outcome (presence of SAD).

Results

Fourteen articles met the predefined criteria. Due to the large heterogeneity, their meta-analysis was not possible. Our review revealed (a) two studies on endothelial dysfunction, out of which one found an inverse relation between plasma trimethylamine N-oxide levels and FMD and the other did not substantiate a statistically significant correlation with RHI. (b) Twelve studies on atheromatosis, assessed as intimal-medial thickness (IMT), coronary artery calcium (CAC) and arterial plaque, of which, seven studies showed statistically significant associations (negative or positive depending on the microorganism or microbiota metabolite) with IMT, one study revealed significant associations with coronary artery calcium, while one showed absence of correlation and four studies reported statistically significant correlations with arterial plaque. (c) Three studies on arterial stiffness (pulse wave velocity - PWV) with two of them concluding in statistically significant association while the third study did not. Some articles investigated multiple of the correlations described and therefore, belonged to more than one section.

Conclusion

Evidence of both positive and inverse associations of gut microbiota composition and their metabolites with different types of SVD has been found. However the small number and heterogeneity of available studies cannot allow to confirm or disprove the hypothesis.

The Correlation of Short-Chain Fatty Acids with Peripheral Arterial Disease in Diabetes Mellitus Patients

Diabetes mellitus (DM) is a significant risk factor for peripheral arterial disease (PAD). PAD affects 20% of DM patients over 40 and has increased by 29% in the last 50 years. The gut microbiota produces short-chain fatty acids (SCFAs) that affect atherosclerosis. SCFA inhibits inflammation, which contributes to atherosclerosis. This study tried to link feces SCFA levels to atherosclerosis in people with diabetes with peripheral arterial disease (PAD). The study included 53 people with diabetes and PAD: gas chromatography-mass spectrometry measured acetate, butyrate, and propionate levels in feces samples (GC-MS). There was a positive correlation between random blood glucose (RBG) levels, peak systolic velocity (PSV), volume flow (VF), plaque, relative and absolute acetate, relative valerate, butyrate, and propionate. This supports the idea that elevated SCFA levels in type 2 diabetic (T2D) patients reduce adipose tissue inflammation and cholesterol metabolism, contributing to atherosclerosis pathogenesis. We conclude that increased fecal SCFA excretion is linked to cardiovascular disease. To determine the causal effect correlation of the SCFA with clinical and laboratory parameters for PAD in DM patients, compare the SCFA in plasma and feces, and account for confounding variables, a specific method with larger sample sizes and more extended follow-up periods is required.

Gut Microbiota, Plasma Metabolomic Profiles, and Carotid Artery Atherosclerosis in HIV Infection

BACKGROUND

Alterations in gut microbiota and blood metabolomic profiles have been implicated in HIV infection and cardiovascular disease. However, it remains unclear whether alterations in gut microbiota may contribute to disrupted host blood metabolomic profiles in relation to atherosclerosis, especially in the context of HIV infection.

METHODS

We analyzed cross-sectional associations between gut microbiota features and carotid artery plaque in 361 women with or at high risk of HIV (67% HIV+), and further integrated plaque-associated microbial features with plasma lipidomic/metabolomic profiles. Furthermore, in 737 women and men, we examined prospective associations of baseline gut bacteria-associated lipidomic and metabolomic profiles with incident carotid artery plaque over 7-year follow-up.

RESULTS

We found 2 potentially pathogenic bacteria, Fusobacterium and Proteus, were associated with carotid artery plaque; while the beneficial butyrate producer Odoribacter was inversely associated with plaque. Fusobacterium and Proteus were associated with multiple lipids/metabolites which were clustered into 8 modules in network. A module comprised of 9 lysophosphatidylcholines and lysophosphatidylethanolamines and a module comprised of 9 diglycerides were associated with increased risk of carotid artery plaque (risk ratio [95% CI], 1.34 [1.09-1.64] and 1.24 [1.02-1.51] per SD increment, respectively). Functional analyses identified bacterial enzymes in lipid metabolism associated with these plasma lipids. In particular, phospholipase A1 and A2 are the key enzymes in the reactions producing lysophosphatidylcholines and lysophosphatidylethanolamines.

CONCLUSIONS

Among individuals with or at high risk of HIV infection, we identified altered gut microbiota and related functional capacities in the lipid metabolism associated with disrupted plasma lipidomic profiles and carotid artery atherosclerosis.

Regulation of neurotoxicity in the striatum and colon of MPTP-induced Parkinson's disease mice by gut microbiome

Increasing evidence suggests the role of gut-microbiota-brain axis in the pathogenesis of Parkinson's disease (PD). The objective of this study was to examine whether repeated administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) can influence the neurotoxicity in the striatum and colon, and the composition of gut microbiota and short-chain fatty acids (SCFAs) in feces of adult mice. MPTP caused the reduction of dopamine transporter (DAT) and tyrosine hydroxylase (TH) in the striatum, and increases in phosphorylated α-synuclein (p-α-Syn) in the striatum and colon. There was a negative correlation between the expression of TH in the striatum and the expression of p-α-Syn in the colon, suggesting a role of gut-brain communication. MPTP caused abnormalities in the α- and β-diversity of gut microbiota in the mice. Furthermore, the relative abundance of the genus Faecalicatena in the MPTP-treated group was significantly lower than that of control group. Interestingly, there was a positive correlation between the genus Faecalicatena and the expression of TH in the striatum. Moreover, MPTP did not alter the levels of SCFAs in feces samples. However, there was a positive correlation between the relative abundance of the genus Faecalicatena and propionic acid. The data suggest that MPTP-induced increases in colonic p-α-Syn expression might be associated with dopaminergic neurotoxicity in the striatum via gut-microbiota-brain axis.