Dietary Influences on the Microbiota-Gut-Brain Axis

Gut microbiota and eye diseases: A review

Recent studies reveal that alterations in gut microbiota play a significant role in the progression of various diseases, including those affecting the eyes. The association between gut microbiota and eye health is an emerging focus of research. This review seeks to summarize the connection between the gut microbiome and specific eye conditions, such as ocular surface diseases, funduscopic disorders and immune-mediated eye diseases. Gut microbiota may influence these conditions by regulating the immune system or altering metabolites, thereby contributing to disease development. Strategies like probiotics, antibiotics, dietary modifications, and fecal transplants show promise in addressing these issues. This review examines how the gut microbiome may be linked to the pathogenesis of eye diseases, providing fresh therapeutic perspectives for ophthalmology.

Serum metabolomic markers of artificially sweetened beverage consumption

BACKGROUND

The consumption of artificially sweetened beverages is on the rise. Use of artificial sweeteners has been associated with adverse health outcomes. There is a need to identify novel objective biomarkers of artificially sweetened beverages in order to improve dietary assessment and to provide insight into their metabolic impact.

OBJECTIVE

We aim to identify serum metabolites that are associated with artificially sweetened beverage consumption.

METHODS

In the Atherosclerosis Risk in Communities (ARIC) study, consumption of artificially sweetened beverages was assessed using a food frequency questionnaire and fasting serum samples were collected during the first study visit (1987-1989). Participants were categorized as "non-users" if they reported almost never consumption of artificially sweetened beverages, "moderate users" for 1 glass/month to 6 glasses/week, and "heavy users" for ≥1 glasses/day. Untargeted metabolomic profiling was conducted in two subgroups (subgroup 1: n=1,866, profiled in 2010; subgroup 2 profiled in 2014: n=2,072) and 360 metabolites were analyzed. In this secondary data analysis, multivariable linear regression models were used, adjusting for demographics, health behaviors, health status, and dietary factors. Analyses were conducted in each subgroup and results were meta-analyzed.

RESULTS

In a meta-analysis of 3,938 generally healthy participants (mean age 54 years, 60% women, 62% Black participants) from ARIC study visit 1, 11 serum metabolites were significantly associated with artificially sweetened beverage consumption. Heavier consumption of artificially sweetened beverages was associated with higher levels of 10 metabolites (saccharin, threonate, erythronate, glycerate, gluconate, mannitol, glucose, tryptophan betaine, trehalose, and N6-acetyllysine) and lower levels of glycocholenate sulfate.

CONCLUSION

We found 11 serum metabolites related to artificially sweetened beverage intake, that consisted of known sugar substitutes, processed food additives, glucose-related compounds, and gut microbiome-related metabolites. These findings enhance our knowledge of the metabolic activity of artificial sweeteners and suggests new biomarkers for monitoring intake.

Distinct functional diversity of branched oligosaccharides as chaperones and inhibitory-binding partners of amyloid beta-protein and its aggregates

Aggregation and deposition of amyloid beta-protein 1-42 (Aβ42) in the brain, primarily owing to hydrophobic interactions between Aβ42 chains, is a common pathology in all forms of Alzheimer's disease (AD). Hydrophilic oligosaccharides are widely present in the extracellular matrix and on the cytoplasmic membrane. To determine if oligosaccharides bind to Aβ42 or its aggregates and consequently affect their aggregation and cellular function, this study examined the interaction of typical functional oligosaccharides with Aβ42 or its aggregates. Isomaltooligosaccharides (IMOs), particularly isomaltotriose, panose, and isomaltotetraose, functioned as molecular chaperones for Aβ42 by binding directly to Aβ42, preserving Aβ42's active conformation and cytotrophic activity. Oral IMOs reduced total plasma Aβ level and indirectly caused a slight reduction in the load of Aβ42 spots/plaques in the brain of AD model mice (male). Another branched oligosaccharide, bianntennary core pentasaccharide (BCP), had a relatively high binding specificity for Aβ42 oligomers (Aβ42O) and acted as an antagonistic binding partner for Aβ42O. Free BCP effectively blocked/prevented further assembly of Aβ42O and their toxicity to neural and vascular endothelial cell lines. Since BCP is also a signaling component of membrane targets (glycolipids, glycoproteins or receptors), it seemed that BCP had two opposing effects on the binding of Aβ42O to target cells. This study's findings suggest that these branched oligosaccharides may be potential candidates for blocking or preventing Aβ42 aggregation and Aβ42O cytotoxicity/neurotoxicity, respectively, and that IMO-like or free BCP-like oligosaccharide deficiencies in the brain may be one of the underlying mechanisms for Aβ42 aggregation and Aβ42O cytotoxicity.

Effects of Lacticaseibacillus rhamnosus HN001 on Happiness and Mental Well-Being: Findings from a Randomized Controlled Trial

BACKGROUND/OBJECTIVES

Lacticaseibacillus rhamnosus HN001 (HN001) is a probiotic strain widely studied for its potential to improve human health. Previous studies have demonstrated promising results for HN001 in the improvement of mental well-being, particularly in terms of increased happiness and support for stress management in healthy adults.

METHODS

To further explore these findings, a double-blind, placebo-controlled trial was conducted with 120 participants aged ≥ 18 years with mild to high stress measured by the Perceived Stress Scale (PSS). The participants were randomly assigned to receive either HN001 or placebo for 28 days. Psychological assessments, including the Oxford Happiness Questionnaire (OHQ), were completed at baseline, day 14, and day 28. Secondary outcomes included changes in PSS scores, as well as depression, anxiety, stress, and total score levels measured by the DASS-21 questionnaire.

RESULTS

While not statistically significant, participants who received HN001 showed an improvement in OHQ (mean change, 13.3) and PSS total scores (mean change, -8.1) over time compared with the placebo group (mean change, 10.2 and -6.6, respectively). Furthermore, 39% of the participants moved from not happy to happy, compared with only 29% in the placebo group. Post-hoc analysis showed a statistically significant interaction between intervention and study day for OHQ and PSS total scores, with p-values of 0.014 and 0.043, respectively. No adverse effects were observed.

CONCLUSIONS

HN001 showed improvements in both happiness and PSS scores. Furthermore, sex subgroup analysis revealed statistically significant differences in both outcomes, emphasizing the need for larger and longer intervention studies.

Dietary and Lifestyle Strategies for Obesity

The prevalence of obesity globally has tripled over the last half century, and currently affects around 650 million adults and 340 million children and adolescents (ages 5-19 years). Obesity contributes towards >50 co-morbidities and premature mortality. Obesity is a highly stigmatised condition that is associated with much mental and emotional distress and dysfunction. Thus, obesity is a major contributor to healthcare expenditure globally. Traditionally, the management of obesity stratifies into three major groups that include metabolic (bariatric) surgery, pharmacotherapies, and lifestyle (primarily dietary) strategies. Although listed as a separate category, dietary strategies for obesity remain a central component of any management plan, and often complement other surgical and pharmacotherapeutic options. Indeed, the effectiveness of any management approach for obesity relies upon successful behavioural changes, particularly relating to eating behaviours. In this concise review, we explore the foundational pillars of dietary strategies for obesity: sleep, listening, routine, de-stressing and optimisation of social conditions. We then discuss the importance of balancing dietary macronutrients (including dietary fibre, carbohydrates, protein and ultra-processed foods [UPFs]) as a key dietary strategy for obesity. Although we focus on general principles, we should provide bespoke dietary strategies for our patients, tailored to their individual needs. Rather than judging the utility of a diet based simply on its associated magnitude of weight loss, we should adopt a more holistic perspective in which a dietary strategy is valued for its overall health benefits, including the nurturing of our gut microbiota, to enable them to nurture and protect us.

Unlocking Dietary Strategies to Combat Neurological Disorders

The acquisition of novel insights derived from the biological and genetic profiles of patients will pave the way for tailored interventions and guidance, facilitated by pioneering methodologies and investigations in research. Such advancements will lead to shifts in dietary patterns and proactively mitigate the onset of neurological disorders.

Diet Quality and Resilience through Adulthood: A Cross-Sectional Analysis of the WELL for Life Study

Despite evidence suggesting the importance of psychological resilience for successful aging, little is known about the relationship between diet quality and resilience at different ages. Our study aims to examine the association between diet quality and resilience across the stages of adulthood. Using Stanfords' WELL for Life (WELL) survey data, we conducted a cross-sectional study of diet quality, resilience, sociodemographic, perceived stress, lifestyle, and mental health factors among 6171 Bay Area adults. Diet quality was measured by the WELL Diet Score, which ranges from 0-120. A higher score indicates a better diet quality. Linear regression analysis was used to evaluate the association between the WELL Diet Score and overall resilience and within the following age groups: early young (18-24), late young (25-34), middle (35-49), and late adulthood (≥50). To test whether these associations varied by age groups, an age group by resilience interaction term was also examined. In the fully adjusted model, the WELL Diet Score was positively and significantly associated with overall resilience (all ages (β = 1.2 ± sd: 0.2, p < 0.001)) and within each age group (early young (β = 1.1 ± sd: 0.3, p < 0.001); late young (β = 1.2 ± sd: 0.3, p < 0.001); middle (β = 0.9 ± sd: 0.3, p < 0.001); and late adulthood (β = 1.0 ± sd: 0.3, p < 0.001)). Young adults demonstrated the strongest associations between diet quality and resilience. However, there were no significant age-by-resilience interactions. Diet quality may be positively associated with resilience at all stages of adulthood. Further research is needed to determine whether assessing and addressing resilience could inform the development of more effective dietary interventions, particularly in young adults.

Effect of the consumption of brazzein and monellin, two recombinant sweet-tasting proteins, on rat gut microbiota

Sweet-tasting proteins (SPs) are proteins of plant origin initially isolated from tropical fruits. They are thousands of times sweeter than sucrose and most artificial sweeteners. SPs are a class of proteins capable of causing a sweet taste sensation in humans when interacting with the T1R2/T1R3 receptor. SP thaumatin has already been introduced in the food industry in some countries. Other SPs, such as monellin and brazzein, are promising products. An important stage in researching SPs, in addition to confirming the absence of toxicity, mutagenicity, oncogenicity, and allergenic effects, is studying their influence on gut microbiota. In this paper we describe changes in the composition of rat gut microbiota after six months of consuming one of two recombinant SPs-brazzein or monellin. A full length 16S gene sequencing method was used for DNA library barcoding. The MaAsLin2 analysis results showed noticeable fluctuations in the relative abundances of Anaerocella delicata in brazzein-fed rat microbiota, and of Anaerutruncus rubiinfantis in monellin-fed rat microbiota, which, however, did not exceed the standard deviation. The sucrose-fed group was associated with an increase in the relative abundance of Faecalibaculum rodentium, which may contribute to obesity. Overall, prolonged consumption of the sweet proteins brazzein and monellin did not significantly change rat microbiota and did not result in the appearance of opportunistic microbiota. This provides additional evidence for the safety of these potential sweeteners.

Gut microbiota, nutrition, and mental health

The human brain remains one of the greatest challenges for modern medicine, yet it is one of the most integral and sometimes overlooked aspects of medicine. The human brain consists of roughly 100 billion neurons, 100 trillion neuronal connections and consumes about 20-25% of the body's energy. Emerging evidence highlights that insufficient or inadequate nutrition is linked to an increased risk of brain health, mental health, and psychological functioning compromise. A core component of this relationship includes the intricate dynamics of the brain-gut-microbiota (BGM) system, which is a progressively recognized factor in the sphere of mental/brain health. The bidirectional relationship between the brain, gut, and gut microbiota along the BGM system not only affects nutrient absorption and utilization, but also it exerts substantial influence on cognitive processes, mood regulation, neuroplasticity, and other indices of mental/brain health. Neuroplasticity is the brain's capacity for adaptation and neural regeneration in response to stimuli. Understanding neuroplasticity and considering interventions that enhance the remarkable ability of the brain to change through experience constitutes a burgeoning area of research that has substantial potential for improving well-being, resilience, and overall brain health through optimal nutrition and lifestyle interventions. The nexus of lifestyle interventions and both academic and clinical perspectives of nutritional neuroscience emerges as a potent tool to enhance patient outcomes, proactively mitigate mental/brain health challenges, and improve the management and treatment of existing mental/brain health conditions by championing health-promoting dietary patterns, rectifying nutritional deficiencies, and seamlessly integrating nutrition-centered strategies into clinical care.

Dietary Fibre for the Prevention of Post-Pancreatitis Diabetes Mellitus: A Review of the Literature and Future Research Directions

Post-pancreatitis diabetes mellitus-the most common sequela of pancreatitis-leads to poorer glycaemic control compared with type 2 diabetes. Because post-pancreatitis diabetes mellitus is an exemplar of secondary diabetes (with a clear underlying cause), much post-pancreatitis diabetes mellitus is preventable or treatable early. Earlier literature established the important role of dietary fibre in reducing plasma glucose in individuals with type 2 diabetes. The present review benchmarks available evidence on the role of habitual dietary fibre intake in pancreatitis and post-pancreatitis diabetes mellitus. It also paves the way for future research on the use of dietary fibre in the post-pancreatitis setting.

Effect of Fiber-Rich Diet and Rope Skipping on Memory, Executive Function, and Gut Microbiota in Young Adults: A Randomized Controlled Trial

SCOPE

To investigate the effects of fiber-rich diets (FDs), rope skipping (RS), and the combination of these two interventions (fiber-rich diet with rope skipping [FD-RS]) on memory, executive function in young adults, and to explore their relationship with gut microbiota.

MATERIALS AND RESULTS

The study is a 12-week parallel-design randomized controlled trial in which 120 undergraduates (19 ± 1 years) are randomized to FD (fiber ≥ 20 g day-1 ), RS (3 × 2000 times per week), FD-RS or control group (n = 30 per group). Memory and executive function are assessed by scales, and stool samples are collected at baseline and after the intervention. FD group and FD-RS group show fewer prospective and retrospective subjective memory impairments than the control group, but there is no significant difference between FD-RS and the intervention alone (FD or RS). No obvious change in executive function is observed throughout the trial. In terms of the gut microbiota, the α-diversity does not increase, but the microbial community evenness improves after the RS and FD intervention. Additionally, the relative abundance of phylum Firmicutes and genera Faecalibacterium, Eubacterium_coprostanoligenes_group in the RS group and NK4A214_group in the FD group significantly increase. In the RS group, a correlation is found between the increase in microbial evenness and the improvement in retrospective memory.

CONCLUSION

The FD and FD-RS have beneficial effects on memory in young adults. Meanwhile, FD and RS can improve the microbial evenness and increase several beneficial genera of phylum Firmicutes.

Interactions between mitochondrial dysfunction and other hallmarks of aging: Paving a path toward interventions that promote healthy old age

Current research on human aging has largely been guided by the milestone paper "hallmarks of aging," which were first proposed in the seminal 2013 paper by Lopez-Otin et al. Most studies have focused on one aging hallmark at a time, asking whether the underlying molecular perturbations are sufficient to drive the aging process and its associated phenotypes. More recently, researchers have begun to investigate whether aging phenotypes are driven by concurrent perturbations in molecular pathways linked to not one but to multiple hallmarks of aging and whether they present different patterns in organs and systems over time. Indeed, preliminary results suggest that more complex interactions between aging hallmarks must be considered and addressed, if we are to develop interventions that successfully promote healthy aging and/or delay aging-associated dysfunction and diseases. Here, we summarize some of the latest work and views on the interplay between hallmarks of aging, with a specific focus on mitochondrial dysfunction. Indeed, this represents a significant example of the complex crosstalk between hallmarks of aging and of the effects that an intervention targeted to a specific hallmark may have on the others. A better knowledge of these interconnections, of their cause-effect relationships, of their spatial and temporal sequence, will be very beneficial for the whole aging research field and for the identification of effective interventions in promoting healthy old age.

Targeting microbiota in dietary obesity management: a systematic review on randomized control trials in adults

Obesity is an alarming public health problem. Tailored nutritional therapy is advisable since emerging evidence on complex cross-talks among multifactorial agents. In this picture, the gut microbiota is highly individualized and intricately dependent on dietary patterns, with implications for obesity management. Most of the papers on the topic are observational and often conflicting. This review aimed to systematically organize the body of evidence on microbiota deriving from dietary trials in adult obesity giving the most certain phylogenetic, and metabolomic signatures in relation to both the host metabolism and phenotype changes published until now. We retrieved 18 randomized control trials on 1385 subjects with obesity who underwent several dietary interventions, including standard diet and healthy dietary regimens. Some phyla and species were more related to diets rich in fibers and others to healthy diets. Weight loss, metabolism improvements, inflammatory markers decrease were specifically related to different microorganisms or functions. The Prevotella/Bacteroides ratio was one of the most reported predictors. People with the burden of obesity comorbidities had the most significant taxonomic changes in parallel with a general improvement. These data emphasize the possibility of using symbiotic approaches involving tailored diets, microbiota characteristics, and maybe drugs to treat obesity and metabolic disorders. We encourage Authors to search for specific phylogenetic associations beyond a too generally reported Firmicutes/Bacteroides ratio.

Roles of Gut Microbiota in Alcoholic Liver Disease

Alcoholic liver disease (ALD)-one of the most common liver diseases - involves a wide range of disorders, including asymptomatic hepatic steatosis, alcoholic hepatitis (AH), liver fibrosis, and cirrhosis. Alcohol consumption induces a weakened gut barrier and changes in the composition of the gut microbiota. The presence of CYP2E1 and its elevated levels in the gastrointestinal tract after alcohol exposure lead to elevated levels of ROS and acetaldehyde, inducing inflammation and oxidative damage in the gut. At the same time, the influx of harmful molecules such as the bacterial endotoxin LPS and peptidogly from gut dysbiosis can induce intestinal inflammation and oxidative damage, further compromising the intestinal mucosal barrier. In this process, various oxidative stress-mediated post-translational modifications (PTMs) play an important role in the integrity of the barrier, eg, the presence of acetaldehyde will result in the sustained phosphorylation of several paracellular proteins (occludin and zona occludens-1), which can lead to intestinal leakage. Eventually, persistent oxidative stress, LPS infiltration and hepatocyte damage through the enterohepatic circulation will lead to hepatic stellate cell activation and hepatic fibrosis. In addition, probiotics, prebiotics, synbiotics, fecal microbial transplantation (FMT), bioengineered bacteria, gut-restricted FXR agonists and others are promising therapeutic approaches that can alter gut microbiota composition to improve ALD. In the future, there will be new challenges to study the interactions between the genetics of individuals with ALD and their gut microbiome, to provide personalized interventions targeting the gut-liver axis, and to develop better techniques to measure microbial communities and metabolites in the body.

Dietary Fat Modulation of Gut Microbiota and Impact on Regulatory Pathways Controlling Food Intake

Obesity is a multifactorial disease that continues to increase in prevalence worldwide. Emerging evidence has shown that the development of obesity may be influenced by taxonomic shifts in gut microbiota in response to the consumption of dietary fats. Further, these alterations in gut microbiota have been shown to promote important changes in satiation signals including gut hormones (leptin, ghrelin, GLP-1, peptide YY and CCK) and orexigenic and anorexigenic neuropeptides (AgRP, NPY, POMC, CART) that influence hyperphagia and therefore obesity. In this review, we highlight mechanisms by which gut microbiota can influence these satiation signals both locally in the gastrointestinal tract and via microbiota-gut-brain communication. Then, we describe the effects of dietary interventions and associated changes in gut microbiota on satiety signals through microbiota-dependent mechanisms. Lastly, we present microbiota optimizing therapies including prebiotics, probiotics, synbiotics and weight loss surgery that can help restore beneficial gut microbiota by enhancing satiety signals to reduce hyperphagia and subsequent obesity. Overall, a better understanding of the mechanisms by which dietary fats induce taxonomical shifts in gut microbiota and their impact on satiation signaling pathways will help develop more targeted therapeutic interventions in delaying the onset of obesity and in furthering its treatment.

Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review

The Western diet is a modern dietary pattern characterized by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy, sweets, fried foods, conventionally raised animal products, high-fat dairy products, and high-fructose products. The present review aims to describe the effect of the Western pattern diet on the metabolism, inflammation, and antioxidant status; the impact on gut microbiota and mitochondrial fitness; the effect of on cardiovascular health, mental health, and cancer; and the sanitary cost of the Western diet. To achieve this goal, a consensus critical review was conducted using primary sources, such as scientific articles, and secondary sources, including bibliographic indexes, databases, and web pages. Scopus, Embase, Science Direct, Sports Discuss, ResearchGate, and the Web of Science were used to complete the assignment. MeSH-compliant keywords such "Western diet", "inflammation", "metabolic health", "metabolic fitness", "heart disease", "cancer", "oxidative stress", "mental health", and "metabolism" were used. The following exclusion criteria were applied: (i) studies with inappropriate or irrelevant topics, not germane to the review's primary focus; (ii) Ph.D. dissertations, proceedings of conferences, and unpublished studies. This information will allow for a better comprehension of this nutritional behavior and its effect on an individual's metabolism and health, as well as the impact on national sanitary systems. Finally, practical applications derived from this information are made.

Longitudinal trajectories of dietary quality and cognitive performance in older adults: Results from a 6-year cohort study

BACKGROUND

Diet affects cognitive performance, but most previous studies only assessed diet once. Trajectory analysis of diet measured at multiple timepoints can identify subpopulations requiring more interventional efforts. We thus assessed associations between dietary trajectories and cognitive performance in older adults.

METHODS

This was a 6-year prospective cohort study involving 356 ethnically Chinese, non-demented, community-dwelling older adults recruited between 2011 and 2013. At baseline and at 4th- and 6th-year follow-ups, dietary intakes of the participants were assessed using food frequency questionnaires. Dietary quality was graded using the modified Alternative Healthy Eating Index (mAHEI) with seven components; longitudinal trajectories of dietary quality were derived using latent growth mixture modelling. Outcomes were global- and domain-specific cognitive performance (attention, memory, executive functions, and verbal fluency). Multivariable regressions adjusting for important covariates (sex, age, energy intake, APOE risk alleles, depressive symptoms, and body mass index (BMI)) assessed associations between the dietary trajectories and cognitive outcomes.

RESULTS

Included participants had a mean age of 71.6 years and a mean BMI of 23.8 kg/m2. Three mutually exclusive dietary quality trajectories, namely "deteriorating", "improving", and "stable-high", were derived. Compared with the stable-high trajectory, the improving trajectory was associated with a lower z-score for the memory domain (β: -0.403; 95% CI: -0.656, -0.151; P = 0.002), which was consistently observed for the four individual tests of the domain (β range: -0.324 to -0.448; all P < 0.05). In unadjusted analysis, the deteriorating trajectory was associated with a 0.369 lower z-score for the verbal fluency domain (95% CI: -0.700, -0.039 P = 0.028), though attenuated to borderline significance with adjustment for covariates. Sex and BMI modified some of these associations. No other associations were observed for global cognition or other cognitive domains.

CONCLUSIONS

In Taiwanese older adults, consistently high dietary quality is associated with better cognitive performance. Interventions to promote and sustain better dietary quality over time can have substantial impacts on cognitive function.

Diarrhea accompanies intestinal inflammation and intestinal mucosal microbiota dysbiosis during fatigue combined with a high-fat diet

OBJECTIVE

It was reported fatigue or a high-fat diet triggers diarrhea, and intestinal microbiota may play central roles in diarrhea. Therefore, we investigated the association between the intestinal mucosal microbiota and the intestinal mucosal barrier from fatigue combined with a high-fat diet.

METHOD

This study divided the Specific pathogen-free (SPF) male mice into the normal group (MCN) and the standing united lard group (MSLD). The MSLD group stood on water environment platform box for 4 h/day for 14 days, and 0.4 mL lard was gavaged from day 8, twice daily for 7 days.

RESULT

After 14 days, Mice in the MSLD group showed diarrhea symptoms. The pathological analysis showed structural damage to the small intestine in the MSLD group, with an increasing trend of interleukin-6 (IL-6) and IL-17, and inflammation accompanied by structural damage to the intestine. Fatigue combined with a high-fat diet considerably decreased Limosilactobacillus vaginalis and Limosilactobacillus reuteri, and among them, Limosilactobacillus reuteri positively associated with Muc2 and negatively with IL-6.

CONCLUSION

The interactions between Limosilactobacillus reuteri and intestinal inflammation might be involved in the process of intestinal mucosal barrier impairment in fatigue combined with high-fat diet-induced diarrhea.

Designer GLP1 poly-agonist peptides in the management of diabesity

INTRODUCTION

To date, the 21^st Century has witnessed key developments in the management of diabesity (a conflation of obesity and Type 2 Diabetes Mellitus [T2D]), including Glucagon Like Peptide 1 (GLP1) receptor agonist therapies, and recently the 'designer' GLP1 Poly-agonist Peptides (GLP1PPs).

AREAS COVERED

A PubMed search of published data on the GLP1PP class of therapies was conducted. The gut-brain axis forms complex multi-directional interlinks that include autonomic nervous signaling, components of the gut microbiota (including metabolic by-products and gram-negative cell wall components [e.g. endotoxinaemia]), and incretin hormones that are secreted from the gut in response to the ingestion of nutrients. The development of dual-incretin agonist therapies includes combinations of the GLP1 peptide with Glucose-dependent Insulinotropic Polypeptide (GIP), Glucagon (Gcg), Cholecystokinin (CCK), Peptide YY (PYY), and Glucagon-Like Peptide 2 (GLP2). Triple incretin agonist therapies are also under development.

EXPERT OPINION

At the dawn of a new era in the therapeutic management of diabesity, the designer GLP1PP class holds great promise, with each novel combination building on a preexisting palimpsest of clinical data and insights. Future innovations of the GLP1PP class will likely enable medically induced weight loss and glycemic control in diabesity to rival or even out-perform those resulting from bariatric surgery.

The Effects of the Mediterranean Diet on Health and Gut Microbiota

The Mediterranean Diet (MD) is plant-based and consists of multiple daily portions of vegetables, fruit, cereals, and olive oil. Although there are challenges with isolating the MD from the typical Mediterranean lifestyle and culture (including prolonged 'social' meals and siestas), much evidence supports the health benefits of the MD that include improved longevity, reduced metabolic risk of Diabetes Mellitus, obesity, and Metabolic Syndrome, reduced risk of malignancy and cardiovascular disease, and improved cognitive function. The MD is also associated with characteristic modifications to gut microbiota, mediated through its constituent parts (primarily dietary fibres, extra virgin olive oil, and polyunsaturated fatty acids [including ω-3]). These include enhanced growth of species that produce short-chain fatty acids (butyrate), such as Clostridium leptum and Eubacterium rectale, enhanced growth of Bifidobacteria, Bacteroides, and Faecalibacterium prausnitzii species, and reduced growth of Firmicutes and Blautia species. Such changes in gut microbiota are known to be associated favourably with inflammatory and oxidative status, propensity for malignancy and overall metabolic health. A key challenge for the future is to explore the extent to which the health benefits of the MD are mediated by such changes to gut microbiota. The MD confers both health and environmental benefits. Adoption of the MD should perhaps be encouraged and facilitated more generally and not just restricted to populations from Mediterranean regions. However, there are key challenges to this approach that include limited perennial availability of the constituent parts of the MD in some non-Mediterranean regions, intolerability of a high-fibre diet for some people, and potential cultural disconnects that juxtapose some traditional (including Western) diets with the MD.

Metabolic-Associated Fatty Liver Disease and the Gut Microbiota

As an important sequela of the burgeoning global obesity problem, metabolic-associated fatty liver disease (MAFLD) has gained increasing prominence recently. The gut-liver axis (GLA) provides a direct conduit to the liver for the gut microbiota and their metabolic by-products (including secondary bile acids, ethanol, and trimethylamine). These GLA-related factors, including the host inflammatory response and integrity of the gut mucosal wall, likely contribute to the pathogenesis of MAFLD. Accordingly, these GLA-related factors are targets for possible preventive and treatment strategies for MAFLD, and include probiotics, prebiotics, bile acids, short-chain fatty acids, fecal microbiota transplantation, carbon nanoparticles, and bacteriophages.

Mechanisms of Prostate Cancer Cells Survival and Their Therapeutic Targeting

Prostate cancer (PCa) is today the second most common cancer in the world, with almost 400,000 deaths annually. Multiple factors are involved in the etiology of PCa, such as older age, genetic mutations, ethnicity, diet, or inflammation. Modern treatment of PCa involves radical surgical treatment or radiation therapy in the stages when the tumor is limited to the prostate. When metastases develop, the standard procedure is androgen deprivation therapy, which aims to reduce the level of circulating testosterone, which is achieved by surgical or medical castration. However, when the level of testosterone decreases to the castration level, the tumor cells adapt to the new conditions through different mechanisms, which enable their unhindered growth and survival, despite the therapy. New knowledge about the biology of the so-called of castration-resistant PCa and the way it adapts to therapy will enable the development of new drugs, whose goal is to prolong the survival of patients with this stage of the disease, which will be discussed in this review.

The increasing prevalence of autoimmunity and autoimmune diseases: an urgent call to action for improved understanding, diagnosis, treatment, and prevention

Autoimmunity is characterized by self-reactive immune components and autoimmune disease by autoimmunity plus pathology. Both autoimmunity and autoimmune diseases are dramatically increasing in many parts of the world, likely as a result of changes in our exposures to environmental factors. Current evidence implicates the momentous alterations in our foods, xenobiotics, air pollution, infections, personal lifestyles, stress, and climate change as causes for these increases. Autoimmune diseases have a major impact on the individuals and families they affect, as well as on our society and healthcare costs, and current projections suggest they may soon take their place among the predominant medical disorders. This necessitates that we increase the scope and scale of our efforts, and coordinate our resources and studies, to understand autoimmune disease risk factors and pathogeneses and improve our diagnostic, therapeutic, and preventive approaches, as the costs of inaction will be profound and far greater without such investments.

René Dubos, the Autochthonous Flora, and the Discovery of the Microbiome

Now characterised by high-throughput sequencing methods that enable the study of microbes without lab culture, the human "microbiome" (the microbial flora of the body) is said to have revolutionary implications for biology and medicine. According to many experts, we must now understand ourselves as "holobionts" like lichen or coral, multispecies superorganisms that consist of animal and symbiotic microbes in combination, because normal physiological function depends on them. Here I explore the 1960s research of biologist René Dubos, a forerunner figure mentioned in some historical accounts of the microbiome, and argue that he arrived at the superorganism concept 40 years before the Human Microbiome Project. This raises the question of why his contribution was not hailed as revolutionary at the time and why Dubos is not remembered for it.

Implications of Resveratrol in Obesity and Insulin Resistance: A State-of-the-Art Review

Background: Resveratrol is a polyphenol chemical that naturally occurs in many plant-based dietary products, most notably, red wine. Discovered in 1939, widespread interest in the potential health benefits of resveratrol emerged in the 1970s in response to epidemiological data on the cardioprotective effects of wine. Objective: To explore the background of resveratrol (including its origins, stability, and metabolism), the metabolic effects of resveratrol and its mechanisms of action, and a potential future role of dietary resveratrol in the lifestyle management of obesity. Data sources: We performed a narrative review, based on relevant articles written in English from a Pubmed search, using the following search terms: “resveratrol”, “obesity”, “Diabetes Mellitus”, and “insulin sensitivity”. Results: Following its ingestion, resveratrol undergoes extensive metabolism. This includes conjugation (with sulfate and glucuronate) within enterocytes, hydrolyzation and reduction within the gut through the action of the microbiota (with the formation of metabolites such as dihydroresveratrol), and enterohepatic circulation via the bile. Ex vivo studies on adipose tissue reveal that resveratrol inhibits adipogenesis and prevents the accumulation of triglycerides through effects on the expression of Peroxisome Proliferator-activated Receptor γ (PPARγ) and sirtuin 1, respectively. Furthermore, resveratrol induces anti-inflammatory effects, supported by data from animal-based studies. Limited data from human-based studies reveal that resveratrol improves insulin sensitivity and fasting glucose levels in patients with Type 2 Diabetes Mellitus and may improve inflammatory status in human obesity. Although numerous mechanisms may underlie the metabolic benefits of resveratrol, evidence supports a role in its interaction with the gut microbiota and modulation of protein targets, including sirtuins and proteins related to nitric oxide, insulin, and nuclear hormone receptors (such as PPARγ). Conclusions: Despite much interest, there remain important unanswered questions regarding its optimal dosage (and how this may differ between and within individuals), and possible benefits within the general population, including the potential for weight-loss and improved metabolic function. Future studies should properly address these important questions before we can advocate the widespread adoption of dietary resveratrol supplementation.

Helpful or harmful? The impact of the ketogenic diet on eating disorder outcomes in type 1 diabetes mellitus

INTRODUCTION

Eating disorders (EDs) are common complications in people with type 1 diabetes (PwT1D), given the rigid focus on food and insulin dose adjustment. Dietary recommendations for T1D match those for the general population, yet many fail to achieve target HbA1c. Evidence suggests that lower carbohydrate meals and thus reduced insulin requirements may decrease inconsistencies in insulin absorption, maintain euglycemia and weight. Dietary restriction is a recognized risk factor for ED development, and Ketogenic Diets (KD) involve restriction of common family-based foods, thus impacting social normality and microbiome diversity. We reviewed the current literature on PwT1D following a KD to understand effects on ED risks.

AREAS COVERED

Published data from MEDLINE, Embase, and PsycINFO were used. Search terms included: type 1 diabetes mellitus; or insulin dependent diabetes or T1D AND EDs or anorexia or bulimia or disordered eating AND low-carbohydrate diet or carbohydrate restricted diet or low carb diet or ketogenic diet.

EXPERT OPINION

Research into the effects of KDs on ED outcomes in PwT1D are limited, given the concerns over risks of diabetic ketoacidosis, hypoglycemia, and dyslipidemia. Longer term studies on the participants' experience and motivations of adhering or admonishing the diet are needed.

Drugs, Guts, Brains, but Not Rock and Roll: The Need to Consider the Role of Gut Microbiota in Contemporary Mental Health and Wellness of Emerging Adults

Emerging adulthood (ages 18-25) is a critical period for neurobiological development and the maturation of the hypothalamic-pituitary-adrenal axis. Recent findings also suggest that a natural perturbation of the gut microbiota (GM), combined with other factors, may create a unique vulnerability during this period of life. The GM of emerging adults is thought to be simpler, less diverse, and more unstable than either younger or older people. We postulate that this plasticity in the GM suggests a role in the rising mental health issues seen in westernized societies today via the gut-brain-microbiota axis. Studies have paid particular attention to the diversity of the microbiota, the specific function and abundance of bacteria, and the production of metabolites. In this narrative review, we focus specifically on diet, physical activity/exercise, substance use, and sleep in the context of the emerging adult. We propose that this is a crucial period for establishing a stable and more resilient microbiome for optimal health into adulthood. Recommendations will be made about future research into possible behavioral adjustments that may be beneficial to endorse during this critical period to reduce the probability of a "dysbiotic" GM and the emergence and severity of mental health concerns.

Potential Effects of Sucralose and Saccharin on Gut Microbiota: A Review

Artificial sweeteners are additives widely used in our diet. Although there is no consensus, current evidence indicates that sucralose and saccharin could influence the gut microbiota. The aim of this study was to analyze the existing scientific evidence on the effects of saccharin and sucralose consumption on gut microbiota in humans. Different databases were used with the following search terms: sweeteners, non-caloric-sweeteners, sucralose, splenda, saccharin, sugartwin, sweet’n low, microbiota, gut microbiota, humans, animal model, mice, rats, and/or in vitro studies. In vitro and animal model studies indicate a dose-dependent relationship between the intake of both sweeteners and gut microbiota affecting both diversity and composition. In humans, long-term study suggests the existence of a positive correlation between sweetener consumption and some bacterial groups; however, most short-term interventions with saccharin and sucralose, in amounts below the ADI, found no significant effect on those groups, but there seems to be a different basal microbiota-dependent response of metabolic markers. Although studies in vitro and in animal models seem to relate saccharin and sucralose consumption to changes in the gut microbiota, more long-term studies are needed in humans considering the basal microbiota of participants and their dietary and lifestyle habits in all population groups. Toxicological and basal gut microbiota effects must be included as relevant factors to evaluate food safety and nutritional consequences of non-calorie sweeteners. In humans, doses, duration of interventions, and number of subjects included in the studies are key factors to interpret the results.

Gut microbiome and prostate cancer

The gut microbiome is linked to several diseases such as Alzheimer's disease, rheumatoid arthritis, and colon cancer. The gut microbiome is also associated with the modulation of immune function, resulting in a different response to immune checkpoint therapy. The gut microbiome differs according to lifestyle, diet, sex, race, genetic background, and country. Lifestyle, especially diet, plays an important role in the development and progression of prostate cancer. Recent studies have revealed a connection between the gut microbiome and prostate cancer. A high-fat diet causes gut dysbiosis and gut bacterial metabolites, such as short-chain fatty acids and phospholipids that enter systemic circulation result in promoting prostate cancer growth. Additionally, the gut microbiota can serve as a source of testosterone, which affects prostate cancer progression. Men with castration-resistant prostate cancer have an increased abundance of gut bacteria with androgenic functions. Men with high-risk prostate cancer share a specific gut microbial profile and profiling gut microbiota could be a potentially effective tool to screen men with high-risk prostate cancer. Lifestyle modifications can improve the gut microbiome. Furthermore, altering the gut microbiome using prebiotic or probiotic interventions may prevent or delay prostate cancer development. Further study into the "Gut-Prostate Axis" would help in the discovery of new strategies for the prevention, screening, and treatment of prostate cancer.

The gut microbiota in retinal diseases

The gut microbiota is a complex ecosystem that inhabits the gastrointestinal tract and consists of archaea, fungi, viruses, and bacteria, with bacteria being dominant. From birth onwards, it coevolves dynamically together with the host. The composition of the gut microbiota is under the influence of a complex interplay between both host and environmental factors. Scientific advances in the past few decades have shown that it is essential in maintaining homeostasis and tipping the balance between health and disease. In addition to its role in food digestion, the gut microbiota is implicated in regulating multiple physiological processes in the host gut mucosa and in distant organs such as the brain. Persistent imbalance between gut microbial communities, termed "dysbiosis," has been associated with several inflammatory and metabolic diseases as well as with central nervous system disorders. In this review, we present the state of the art of current knowledge on an emerging concept, the microbiota-retina axis, and the potential role of its disturbance in the development of retinopathies. We also describe several microbiota-targeting strategies that could constitute preventive and therapeutic tools for retinopathies.

Non-Alcoholic Fatty Liver Disease (NAFLD) and Potential Links to Depression, Anxiety, and Chronic Stress

Non-alcoholic fatty liver disease (NAFLD) constitutes the most common liver disease worldwide, and is frequently linked to the metabolic syndrome. The latter represents a clustering of related cardio-metabolic components, which are often observed in patients with NAFLD and increase the risk of cardiovascular disease. Furthermore, growing evidence suggests a positive association between metabolic syndrome and certain mental health problems (e.g., depression, anxiety, and chronic stress). Given the strong overlap between metabolic syndrome and NAFLD, and the common underlying mechanisms that link the two conditions, it is probable that potentially bidirectional associations are also present between NAFLD and mental health comorbidity. The identification of such links is worthy of further investigation, as this can inform more targeted interventions for patients with NAFLD. Therefore, the present review discusses published evidence in relation to associations of depression, anxiety, stress, and impaired health-related quality of life with NAFLD and metabolic syndrome. Attention is also drawn to the complex nature of affective disorders and potential overlapping symptoms between such conditions and NAFLD, while a focus is also placed on the postulated mechanisms mediating associations between mental health and both NAFLD and metabolic syndrome. Relevant gaps/weaknesses of the available literature are also highlighted, together with future research directions that need to be further explored.

Enhancing Human Superorganism Ecosystem Resilience by Holistically ‘Managing Our Microbes’

Microbes in the 21st century are understood as symbionts ‘completing’ the human ‘superorganism’ (Homo sapiens plus microbial partners-in-health). This paper addresses a significant paradox: despite the vast majority of our genes being microbial, the lack of routine safety testing for the microbiome has led to unintended collateral side effects from pharmaceuticals that can damage the microbiome and inhibit innate ‘colonization resistance’ against pathobionts. Examples are discussed in which a Microbiome First Medicine approach provides opportunities to ‘manage our microbes’ holistically, repair dysbiotic superorganisms, and restore health and resilience in the gut and throughout the body: namely, managing nosocomial infections for Clostridioides difficile and Staphylococcus aureus and managing the gut and neural systems (gut–brain axis) in autism spectrum disorder. We then introduce a risk analysis tool: the evidence map. This ‘mapping’ tool was recently applied by us to evaluate evidence for benefits, risks, and uncertainties pertaining to the breastmilk ecosystem. Here, we discuss the potential role of the evidence map as a risk analysis methodology to guide scientific and societal efforts to: (1) enhance ecosystem resilience, (2) ‘manage our microbes’, and (3) minimize the adverse effects of both acute and chronic diseases.

Microbiota-gut-brain axis: A novel potential target of ketogenic diet for epilepsy

Ketogenic diet (KD) has been used to the control of seizure for 100 years because it was developed for the treatment of epilepsy in 1921. Based on current research on the microbiota-gut-brain axis to explore the new communication tool between gut bacteria and the brain and the progress of microbiota-gut-brain axis and KD for the treatment of epilepsy, the role of neurotransmitters adenosine and γ-aminobutyric acid in the epileptic brain, we propose that the balance between beneficial and harmful bacteria in the gut microbiota would be a promising target in the future to underlying the working mechanism of KD for epilepsy.

Does chronic inflammation cause acute inflammation to spiral into hyper-inflammation in a manner modulated by diet and the gut microbiome, in severe Covid-19?

We propose that hyper-inflammation (HYPi) is a ''runaway'' consequence of acute inflammation (ACUi) that arises more easily (and also abates less easily) in those who host a pre-existing chronic inflammation (CHRi), because (i) most factors involved in generating an ACUi to limit viral proliferation are already present when there is an underlying CHRi, and also because (ii) anti-inflammatory (AI) mechanisms for the abatement of ACUi (following containment of viral proliferation) are suppressed and desensitized where there is an underlying CHRi, with this causing the ACUi to spiral into a HYPi. Stress, pollution, diet, and gut microbiomes (alterable in weeks through dietary changes) have an intimate and bidirectional cause-effect relationship with CHRi. We propose that avoidance of CHRi-promoting foods and adoption of CHRi-suppressing foods could reduce susceptibility to HYPi, in Covid-19 and in other viral diseases, such as influenza, which are characterized by episodic and unpredictable HYPi.

Water-soluble palm fruit extract: composition, biological properties, and molecular mechanisms for health and non-health applications

The oil palm (Elaeis guineensis) fruit is a source of vegetable oil and various phytonutrients. Phytochemical compounds present in palm oil include tocotrienols, carotenoids, phytosterols, squalene, coenzyme Q₁₀, and phospholipids. Being a fruit, the oil palm is also a rich source of water-soluble phytonutrients, including phenolic compounds. Extraction of phytonutrients from the oil palm vegetation liquor of palm oil milling results in a phenolic acid-rich fraction termed Water-Soluble Palm Fruit Extract (WSPFE). Pre-clinical in vitro, ex vivo, and in vivo studies carried out using various biological models have shown that WSPFE has beneficial bioactive properties, while clinical studies in healthy volunteers showed that it is safe for human consumption and confers antioxidant and anti-inflammatory effects. The composition, biological properties, and relevant molecular mechanisms of WSPFE discovered thus far are discussed in the present review, with a view to offer future research perspectives on WSPFE for health and non-health applications.