Changes in Weight Status and the Intestinal Microbiota Among College Freshman, Aged 18 Years

Gut Microbiota: Potential Therapeutic Target for Sickle Cell Disease Pain and Complications

Aim

Sickle cell disease has witnessed a 41.4% surge from 2000 to 2021, significantly affecting morbidity and mortality rates, particularly in children from regions with elevated under-5 mortality rates. Gut microbiota dysbiosis is increasingly recognised in SCD, exacerbating complications, particularly chronic pain, marked by significant alterations of proinflammatory bacteria abundance. This review explores the therapeutic potential of Akkermansia muciniphila and Roseburia spp. in alleviating SCD-related complications, emphasising their roles in maintaining gut barrier integrity, reducing inflammation, and modulating immune responses.

Method

A literature search up to November 2023 using PubMed, MEDLINE, and Google Scholar databases explored SCD pathophysiology, gut microbiota composition, Akkermansia muciniphila and Roseburia spp. abundance, pain and gut dysbiosis in SCD, and butyrate therapy.

Result

A. muciniphila and Roseburia spp. supplementation shows promise in alleviating chronic pain by addressing gut dysbiosis, offering new avenues for sustainable SCD management. This approach holds the potential for reducing reliance on reactive treatments and improving overall quality of life. This research underscores the pivotal role of the gut microbiome in SCD, advocating for personalised treatment approaches.

Conclusion

Further exploration and clinical trials are needed to harness the full potential of these gut bacteria for individuals affected by this challenging condition.

The Human Gut Microbiota: A Dynamic Biologic Factory

The human body constitutes a living environment for trillions of microorganisms, which establish the microbiome and, the largest population among them, reside within the gastrointestinal tract, establishing the gut microbiota. The term "gut microbiota" refers to a set of many microorganisms [mainly bacteria], which live symbiotically within the human host. The term "microbiome" means the collective genomic content of these microorganisms. The number of bacterial cells within the gut microbiota exceeds the host's cells; collectively and their genes quantitatively surpass the host's genes. Immense scientific research into the nature and function of the gut microbiota is unraveling its roles in certain human health activities such as metabolic, physiology, and immune activities and also in pathologic states and diseases. Interestingly, the microbiota, a dynamic ecosystem, inhabits a particular environment such as the human mouth or gut. Human microbiota can evolve and even adapt to the host's unique features such as eating habits, genetic makeup, underlying diseases, and even personalized habits. In the past decade, biologists and bioinformaticians have concentrated their research effort on the potential roles of the gut microbiome in the development of human diseases, particularly immune-mediated diseases and colorectal cancer, and have initiated the assessment of the impact of the gut microbiome on the host genome. In the present chapter, we focus on the biological features of gut microbiota, its physiology as a biological factory, and its impacts on the host's health and disease status.

Metabolomic and Transcriptomic Analysis of Effects of Three MUFA-Rich Oils on Hepatic Glucose and Lipid Metabolism in Mice

SCOPE

Olive oil, rapeseed oil, and lard are dietary fats rich in monounsaturated fatty acids, but the effects of dietary oils enriched in monounsaturated fatty acids on hepatic lipid deposition have seldom been compared.

METHODS AND RESULTS

Ninety 8-week-old C57BL/6J male mice are randomly divided into six groups and fed diets containing lard, rapeseed oil, or olive oil with a 10% or 45% fat energy supply for 16 weeks. Under high-fat conditions, serum total cholesterol levels in the lard and olive oil groups are significantly higher than those in the rapeseed oil group. Hepatic lipid content in the olive oil group is higher than that in the other two groups. Compared with rapeseed oil, lard increases the liver levels of arachidonic, palmitic, and myristic acids and decreases the levels of eicosapentaenoic linolenic acid and linoleic acid. Olive oil increases the liver levels of docosatrienoic, arachidonic, oleic, and myristic acids; maltose; and fructose and decreases the levels of eicosapentaenoic, linolenic, and linoleic acids.

CONCLUSION

Olive oil probably causes hepatic lipid deposition in mice, which may enhance hepatic lipid synthesis by activating the starch and sucrose metabolic pathways. By contrast, rapeseed oil shows a significant anti-lipid deposition effect on the liver.

A microbial causal mediation analytic tool for health disparity and applications in body mass index

BACKGROUND

Emerging evidence suggests the potential mediating role of microbiome in health disparities. However, no analytic framework can be directly used to analyze microbiome as a mediator between health disparity and clinical outcome, due to the non-manipulable nature of the exposure and the unique structure of microbiome data, including high dimensionality, sparsity, and compositionality.

METHODS

Considering the modifiable and quantitative features of the microbiome, we propose a microbial causal mediation model framework, SparseMCMM_HD, to uncover the mediating role of microbiome in health disparities, by depicting a plausible path from a non-manipulable exposure (e.g., ethnicity or region) to the outcome through the microbiome. The proposed SparseMCMM_HD rigorously defines and quantifies the manipulable disparity measure that would be eliminated by equalizing microbiome profiles between comparison and reference groups and innovatively and successfully extends the existing microbial mediation methods, which are originally proposed under potential outcome or counterfactual outcome study design, to address health disparities.

RESULTS

Through three body mass index (BMI) studies selected from the curatedMetagenomicData 3.4.2 package and the American gut project: China vs. USA, China vs. UK, and Asian or Pacific Islander (API) vs. Caucasian, we exhibit the utility of the proposed SparseMCMM_HD framework for investigating the microbiome's contributions in health disparities. Specifically, BMI exhibits disparities and microbial community diversities are significantly distinctive between reference and comparison groups in all three applications. By employing SparseMCMM_HD, we illustrate that microbiome plays a crucial role in explaining the disparities in BMI between ethnicities or regions. 20.63%, 33.09%, and 25.71% of the overall disparity in BMI in China-USA, China-UK, and API-Caucasian comparisons, respectively, would be eliminated if the between-group microbiome profiles were equalized; and 15, 18, and 16 species are identified to play the mediating role respectively.

CONCLUSIONS

The proposed SparseMCMM_HD is an effective and validated tool to elucidate the mediating role of microbiome in health disparity. Three BMI applications shed light on the utility of microbiome in reducing BMI disparity by manipulating microbial profiles. Video Abstract.

Health and Disease: Akkermansia muciniphila, the Shining Star of the Gut Flora

Akkermansia muciniphila (A. muciniphila) has drawn much attention as an important gut microbe strain in recent years. A. muciniphila can influence the occurrence and development of diseases of the endocrine, nervous, digestive, musculoskeletal, and respiratory systems and other diseases. It can also improve immunotherapy for some cancers. A. muciniphila is expected to become a new probiotic in addition to Lactobacillus and Bifidobacterium. An increase in A. muciniphila abundance through direct or indirect A. muciniphila supplementation may inhibit or even reverse disease progression. However, some contrary findings are found in type 2 diabetes mellitus and neurodegenerative diseases, where increased A. muciniphila abundance may aggravate the diseases. To enable a more comprehensive understanding of the role of A. muciniphila in diseases, we summarize the relevant information on A. muciniphila in different systemic diseases and introduce regulators of A. muciniphila abundance to promote the clinical transformation of A. muciniphila research.

A microbial causal mediation analytic tool for health disparity and applications in body mass index

Background: Emerging evidence suggests the potential mediating role of microbiome in health disparities. However, no analytic framework is available to analyze microbiome as a mediator between health disparity and clinical outcome, due to the unique structure of microbiome data, including high dimensionality, sparsity, and compositionality. Methods: Considering the modifiable and quantitative features of microbiome, we propose a microbial causal mediation model framework, SparseMCMM_HD, to uncover the mediating role of microbiome in health disparities, by depicting a plausible path from a non-manipulable exposure (e.g. race or region) to a continuous outcome through microbiome. The proposed SparseMCMM_HD rigorously defines and quantifies the manipulable disparity measure that would be eliminated by equalizing microbiome profiles between comparison and reference groups. Moreover, two tests checking the impact of microbiome on health disparity are proposed. Results: Through three body mass index (BMI) studies selected from the curatedMetagenomicData 3.4.2 package and the American gut project: China vs. USA, China vs. UK, and Asian or Pacific Islander (API) vs. Caucasian, we exhibit the utility of the proposed SparseMCMM_HD framework for investigating microbiome’s contributions in health disparities. Specifically, BMI exhibits disparities and microbial community diversities are significantly distinctive between the reference and comparison groups in all three applications. By employing SparseMCMM_HD, we illustrate that microbiome plays a crucial role in explaining the disparities in BMI between races or regions. 11.99%, 12.90%, and 7.4% of the overall disparity in BMI in China-USA, China-UK, and API-Caucasian comparisons, respectively, would be eliminated if the between-group microbiome profiles were equalized; and 15, 21, and 12 species are identified to play the mediating role respectively. Conclusions: The proposed SparseMCMM_HD is an effective and validated tool to elucidate the mediating role of microbiome in health disparity. Three BMI applications shed light on the utility of microbiome in reducing BMI disparity by manipulating microbial profiles.

Association of food insecurity on gut microbiome and metabolome profiles in a diverse college-based sample

Voluntary caloric restriction (e.g., eating disorders) often results in alterations in the gut microbiota composition and function. However, these findings may not translate to food insecurity, where an individual experiences inconsistent access to healthy food options. In this study we compared the fecal microbiome and metabolome of racially and ethnically diverse first year college students (n = 60) experiencing different levels of food access. Students were dichotomized into food secure (FS) and food insecure (FI) groups using a validated, 2-question screener assessing food security status over the previous 30 days. Fecal samples were collected up to 5 days post survey-completion. Gut microbiome and metabolome were established using 16S rRNA amplicon sequencing, targeted liquid chromatography-tandem mass spectrometry, and gas chromatography-mass spectrometry. FI students experienced significantly greater microbial diversity with increased abundance of Enterobacteriaceae and Eisenbergiella, while FS students had greater abundance of Megasphaera and Holdemanella. Metabolites related to energy transfer and gut–brain-axis communication (picolinic acid, phosphocreatine, 2-pyrrolidinone) were elevated in FI students (q < 0.05). These findings suggest that food insecurity is associated with differential gut microbial and metabolite composition for which the future implications are unknown. Further work is needed to elucidate the longitudinal metabolic effects of food insecurity and how gut microbes influence metabolic outcomes.

Akkermansia muciniphila: is it the Holy Grail for ameliorating metabolic diseases?

The increasing prevalence of metabolic diseases has become a severe public health problem. Gut microbiota play important roles in maintaining human health by modulating the host's metabolism. Recent evidences demonstrate that Akkermansia muciniphila is effective in improving metabolic disorders and is thus considered as a promising "next-generation beneficial microbe". In addition to the live A. muciniphila, similar or even stronger beneficial effects have been observed in pasteurized A. muciniphila and its components, including the outer membrane protein Amuc_1100, A. muciniphila-derived extracellular vesicles (AmEVs), and secreted protein P9. Hence, this paper presents a systemic review of recent progress in the effects and mechanisms of A. muciniphila and its components in the treatment of metabolic diseases, including obesity, type 2 diabetes mellitus, cardiovascular disease, and nonalcoholic fatty liver disease, as well as perspectives on its future study.