The Use of Probiotic Therapy in Metabolic and Neurological Diseases

An integrative exploration of environmental stressors on the microbiome-gut-brain axis and immune mechanisms promoting neurological disorders

The microbiome-gut-brain axis is altered by environmental stressors such as heat, diet, and pollutants as well as microbes in the air, water, and soil. These stressors might alter the host's microbiome and symbiotic relationship by modifying the microbial composition or location. Compartmentalized mutualistic microbes promote the beneficial interactions in the host leading to circulating metabolites and hormones such as insulin and leptin that affect inter-organ functions. Inflammation and oxidative stress induced by environmental stressors may alter the composition, distribution, and activities of the microbes in the microbiomes such that the resultant metabolite and hormone changes are no longer beneficial. The microbiome-gut-brain axis and immune adverse changes that may accompany environmental stressors are reviewed for effects on innate and adaptive immune cells, which may make host immunity less responsive to pathogens and more reactive to self-antigens. Cardiovascular and fluid exchanges to organs might adversely alter organ functionality. Organs, especially the brain, need a consistent supply of nutrients and clearance of debris; disruption of these exchanges by stressors, and involvement of gut microbiome are discussed regarding neural dysfunctions with Alzheimer's disease, autistic spectrum disorders, viral infections, and autoimmune diseases. The focus of this review includes the manner in which environmental stressors may disrupt gut microbiota leading to adverse immune and hormonal influences on development of neuropathology related to hyperhomocysteinemia, inflammation, and oxidative stress, and how certain therapeutics may be beneficial. Strategies are explored to lessen detrimental effects of environmental stressors on central and peripheral health navigated toward (1) understanding neurological disorders and (2) promoting environmental and public health and well-being.

Engineered probiotic cocktail with two cascade metabolic Escherichia coli for the treatment of hyperlysinemia

Engineering probiotics have emerged as a potential strategy for the treatment of metabolic diseases. However, due to the exceptional complexity of these metabolic disorders and the intricate relationship between gut microbes, it is difficult to achieve an ideal therapeutic effect in a specific metabolic disorder using only a single engineered strain. In this work, we proposed a probiotic cocktail strategy by engineering two cascade metabolic bacteria to treat hyperlysinemia, an inherited lysine metabolic disorder with loss of α-aminoadipate semialdehyde synthase (AASS) activity. A probiotic E. coli Nissle 1917 strain EcNT (pTLS) with a heterologous enzyme pathway in Saccharomyces cerevisiae was engineered to metabolize the excess lysine. Another one EcNT (pK25) was engineered to consume the products of lysine metabolism. The bacterial cocktail enables the maintenance of a metabolic cascade with AASS-like functional activity to maintain the blood lysine concentrations and downstream metabolites. In vitro experimental results showed that the cocktail bacteria had a better metabolic capacity and metabolites balance at a ratio of EcNT (pTLS) and EcNT (pK25) of 1:2. Feeding of the cocktail bacteria to the mouse model effectively reduced the concentration of lysine and balanced saccharopine in the plasma of hyperlysinemia-like mice. These findings not only provide a promising strategy of probiotic stains for the treatment of hyperlysinemia but also highlight the potential of engineered cascade cocktails to intervene and even cure other inherited metabolic diseases.

Microbiome-modulating nutraceuticals ameliorate dyslipidemia in type 2 diabetes: A systematic review, meta-analysis, and meta-regression of clinical trials

AIMS

Type 2 Diabetes is intrinsically linked to cardiovascular disease (CVD) via diabetic dyslipidemia, both of which remain global health concerns with annually increasing prevalence. Given the established links between gut microbiome dysbiosis and metabolic diseases, its modulation is an attractive target to ameliorate metabolic imbalances in such patients. There is a need to quantitively summarise, analyse, and describe future directions in this field.

METHODS

We conducted a systematic review, meta-analysis, and meta-regression following searches in major scientific databases for clinical trials investigating the effect of pro/pre/synbiotics on lipid profile published until April 2022. Data were pooled using random-effects meta-analysis and reported as mean differences with 95% confidence intervals (CIs). PROSPERO No. CRD42022348525.

RESULTS

Data from 47 trial comparisons across 42 studies (n = 2692) revealed that, compared to placebo/control groups, the administration of pro/pre/synbiotics was associated with statistically significant changes in total cholesterol (-9.97 mg/dL [95% CI: -15.08; -4.87], p < 0.0001), low-density lipoprotein (-6.29 mg/dL [95% CI: -9.25; -3.33], p < 0.0001), high-density lipoprotein (+3.21 mg/dL [95% CI: 2.20; 4.22], p < 0.0001), very-low-density lipoprotein (-4.52 mg/dL [95% CI: -6.36; -2.67], p < 0.0001) and triglyceride (-22.93 mg/dL [95% CI: -33.99; -11.87], p < 0.001). These results are influenced by patient characteristics such as age or baseline BMI, and intervention characteristics such as dosage and duration.

CONCLUSIONS

Our study shows that adjunct supplementation with a subset of pro/pre/synbiotics ameliorates dyslipidemia in diabetic individuals and has the potential to reduce CVD risk. However, widespread inter-study heterogeneity and the presence of several unknown confounders limit their adoption in clinical practice; future trials should be designed with these in mind.

Bifidobacteria in Fermented Dairy Foods: A Health Beneficial Outlook

Bifidobacteria, frequently present in the human gastrointestinal tract, play a crucial role in preserving gut health and are mostly recognized as beneficial probiotic microorganisms. They are associated with fermenting complex carbohydrates, resulting in the production of short-chain fatty acids, bioactive peptides, exopolysaccharides, and vitamins, which provide energy and contribute to gut homeostasis. In light of these findings, research in food processing technologies has harnessed probiotic bacteria such as lactobacilli and bifidobacteria for the formulation of a wide range of fermented dairy products, ensuring their maximum survival and contributing to the development of distinctive quality characteristics and therapeutic benefits. Despite the increased interest in probiotic dairy products, introducing bifidobacteria into the dairy food chain has proved to be complicated. However, survival of Bifidobacterium species is conditioned by strain of bacteria used, metabolic interactions with lactic acid bacteria (LAB), fermentation parameters, and the temperature of storage and preservation of the dairy products. Furthermore, fortification of dairy foods and whey beverages with bifidobacteria have ability to change physicochemical and rheological properties beyond economic value of dairy products. In summary, this review underscores the significance of bifidobacteria as probiotics in diverse fermented dairy foods and accentuates their positive impact on human health. By enhancing our comprehension of the beneficial repercussions associated with the consumption of bifidobacteria-rich products, we aim to encourage individuals to embrace these probiotics as a means of promoting holistic health.

The Gut-Organ Axis within the Human Body: Gut Dysbiosis and the Role of Prebiotics

The human gut microbiota (GM) is a complex microbial ecosystem that colonises the gastrointestinal tract (GIT) and is comprised of bacteria, viruses, fungi, and protozoa. The GM has a symbiotic relationship with its host that is fundamental for body homeostasis. The GM is not limited to the scope of the GIT, but there are bidirectional interactions between the GM and other organs, highlighting the concept of the "gut-organ axis". Any deviation from the normal composition of the GM, termed "microbial dysbiosis", is implicated in the pathogenesis of various diseases. Only a few studies have demonstrated a relationship between GM modifications and disease phenotypes, and it is still unknown whether an altered GM contributes to a disease or simply reflects its status. Restoration of the GM with probiotics and prebiotics has been postulated, but evidence for the effects of prebiotics is limited. Prebiotics are substrates that are "selectively utilized by host microorganisms, conferring a health benefit". This study highlights the bidirectional relationship between the gut and vital human organs and demonstrates the relationship between GM dysbiosis and the emergence of certain representative diseases. Finally, this article focuses on the potential of prebiotics as a target therapy to manipulate the GM and presents the gaps in the literature and research.

Probiotics: Protecting Our Health from the Gut

The gut microbiota (GM) comprises billions of microorganisms in the human gastrointestinal tract. This microbial community exerts numerous physiological functions. Prominent among these functions is the effect on host immunity through the uptake of nutrients that strengthen intestinal cells and cells involved in the immune response. The physiological functions of the GM are not limited to the gut, but bidirectional interactions between the gut microbiota and various extraintestinal organs have been identified. These interactions have been termed interorganic axes by several authors, among which the gut–brain, gut–skin, gut–lung, gut–heart, and gut–metabolism axes stand out. It has been shown that an organism is healthy or in homeostasis when the GM is in balance. However, altered GM or dysbiosis represents a critical factor in the pathogenesis of many local and systemic diseases. Therefore, probiotics intervene in this context, which, according to various published studies, allows balance to be maintained in the GM, leading to an individual’s good health.

Emerging Role and Place of Probiotics in the Management of Pediatric Neurodevelopmental Disorders

The current decade has witnessed significant developments with the latest therapeutic agents for managing various infectious diseases to complex hemato-oncological conditions, leading to a decrease in morbidity and mortality, while improving the quality of life (QoL), and increasing the life span. Non-communicable diseases (NCDs), which are on the rise across all age-groups, are being driven by unhealthy lifestyles and improved mental health issues. The current therapeutic agents were found to offer only symptomatic relief of varying efficacy and significant adverse effects, leading clinicians to evaluate other options for the management of both neurodevelopmental and neurodegenerative disorders. The role of gut microbiota has emerged as a potential target for the treatment of both neurodegenerative diseases and neurodevelopmental disorders like attention-deficit hyperactivity disorder (ADHD)/autism spectrum disorders (ASD) as a result of the decoding of the human genome and advances in our understanding of the human gut microbiome, including its interactions with the human brain. This review has been undertaken to understand on date level of understanding of human microbiota and towards identifying probiotic strains with proven efficacy and safety. According to recent investigations, several lactobacillus strains, including L. Paracasei 37, L. Planetarium 128, L. reuteri DSM 17938, and Bifidobacterium longum, have been effective in treating children's neurodevelopmental disorders such as ASD and ADHD. Future clinical studies are nonetheless required to confirm the long-term safety and effectiveness of probiotic strains in managing the primary and comorbid symptoms, hence improving patient and family quality of life.

How to cite this article

Khanna HN, Roy S, Shaikh A, et al. Emerging Role and Place of Probiotics in the Management of Pediatric Neurodevelopmental Disorders. Euroasian J Hepato-Gastroenterol 2022;12(2):102-108.