The Effects of Prebiotics, Synbiotics, and Short-Chain Fatty Acids on Respiratory Tract Infections and Immune Function: A Systematic Review and Meta-Analysis

Revolutionizing lung health: Exploring the latest breakthroughs and future prospects of synbiotic nanostructures in lung diseases

The escalating prevalence of lung diseases underscores the need for innovative therapies. Dysbiosis in human body microbiome has emerged as a significant factor in these diseases, indicating a potential role for synbiotics in restoring microbial equilibrium. However, effective delivery of synbiotics to the target site remains challenging. Here, we aim to explore suitable nanoparticles for encapsulating synbiotics tailored for applications in lung diseases. Nanoencapsulation has emerged as a prominent strategy to address the delivery challenges of synbiotics in this context. Through a comprehensive review, we assess the potential of nanoparticles in facilitating synbiotic delivery and their structural adaptability for this purpose. Our review reveals that nanoparticles such as nanocellulose, starch, and chitosan exhibit high potential for synbiotic encapsulation. These offer flexibility in structure design and synthesis, making them promising candidates for addressing delivery challenges in lung diseases. Furthermore, our analysis highlights that synbiotics, when compared to probiotics alone, demonstrate superior anti-inflammatory, antioxidant, antibacterial and anticancer activities. This review underscores the promising role of nanoparticle-encapsulated synbiotics as a targeted and effective therapeutic approach for lung diseases, contributing valuable insights into the potential of nanomedicine in revolutionizing treatment strategies for respiratory conditions, ultimately paving the way for future advancements in this field.

Managing children with frequent respiratory infections and associated wheezing: a preliminary randomized study with a new multicomponent nasal spray

BACKGROUND

Preschoolers frequently have respiratory infections (RIs), which may cause wheezing in some subjects. Type 2 polarization may favor increased susceptibility to RIs and associated wheezing. Non-pharmacological remedies are garnering increasing interest as possible add-on therapies. The present preliminary study investigated the efficacy and safety of a new multi-component nasal spray in preschoolers with frequent RIs and associated wheezing.

METHODS

Some preschoolers with these characteristics randomly took this product, containing lactoferrin, dipotassium glycyrrhizinate, carboxymethyl-beta-glucan, and vitamins C and D3 (Saflovir), two sprays per nostril twice daily for 3 months. Other children were randomly treated only with standard therapy. Outcomes included the number of RIs and wheezing episodes, use of medications, and severity of clinical manifestations.

RESULTS

Preschoolers treated add-on with this multicomponent product experienced fewer RIs and used fewer beta-2 agonists than untreated children (P = 0.01 and 0.029, respectively).

CONCLUSIONS

This preliminary study demonstrated that a multicomponent product, administered add-on as a nasal spray, could reduce the incidence of RIs and use of symptomatic drugs for relieving wheezing in children.

Probiotics, prebiotics, and postbiotics in health and disease

The gut microbiota and its homeostasis play a crucial role in human health. However, for some diseases related to the gut microbiota, current traditional medicines can only relieve symptoms, and it is difficult to solve the root causes or even cause side effects like disturbances in the gut microbiota. Increasing clinical studies and evidences have demonstrated that probiotics, prebiotics, and postbiotics can prevent and treat various diseases, but currently they can only be used as dietary supplements rather than medicines, which restricts the application of probiotics in the field of medicine. Here, this review analyzes the importance of gut microbiota in human health and the current problems of traditional medicines, and systematically summarizes the effectiveness and mechanisms of probiotics, prebiotics, and postbiotics in maintaining health and treating diseases based on animal models and clinical trials. And based on current research outcomes and development trends in this field, the challenges and prospects of their clinical application in maintaining health, alleviating and treating diseases are analyzed. It is hoped to promote the application of probiotics, prebiotics, and postbiotics in disease treatment and open up new frontiers in probiotic research.

Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota

Short-chain fatty acids (SCFAs) play a key role in health and disease, as they regulate gut homeostasis and their deficiency is involved in the pathogenesis of several disorders, including inflammatory bowel diseases, colorectal cancer, and cardiometabolic disorders. SCFAs are metabolites of specific bacterial taxa of the human gut microbiota, and their production is influenced by specific foods or food supplements, mainly prebiotics, by the direct fostering of these taxa. This Review provides an overview of SCFAs' roles and functions, and of SCFA-producing bacteria, from their microbiological characteristics and taxonomy to the biochemical process that lead to the release of SCFAs. Moreover, we will describe the potential therapeutic approaches to boost the levels of SCFAs in the human gut and treat different related diseases.

The Link between Different Types of Prebiotics in Infant Formula and Infection Rates: A Review

Breastfeeding plays a protective role against infections, partially through the prebiotic effect of human milk oligosaccharides (HMOs). Aiming to mimic these beneficial capacities, there is an ongoing search to make infant formula closer to human milk, including by adding oligosaccharides. Over the past two decades, multiple studies have been published on different types of prebiotics and their role in reducing infection rates in infants. This review aims to answer the question of whether there is evidence that the addition of oligosaccharides to infant formula decreases the prevalence of infection, and whether the effect is influenced by the kind of oligosaccharide added. The review of the literature reveals an important heterogeneity, including different types and dosages of prebiotics, different intervention periods and inclusion criteria, etc., making it impossible to formulate a consensus about the efficacy of adding prebiotics to infant formula. We would cautiously suggest that supplementation with galactooligosaccharides (GOSs)/fructooligosaccharides (FOSs) seems to have a beneficial effect on infection rates. For HMOs, more studies about the different types of HMOs are necessary to make any deductions. GOSs alone, inulin, and MOSs (bovine-milk-derived oligosaccharides) do not reduce the incidence of infections. The combination of GOSs and PDX (polydextrose) was found to play a protective role in one study. The evidence of the effect of prebiotics in reducing the use of antibiotics is low. The many lacunas in the direction of study uniformity offer many opportunities for further research.

Orally Ingested Probiotics, Prebiotics, and Synbiotics as Countermeasures for Respiratory Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis

The impact of gut microbiota-targeted interventions on the incidence, duration, and severity of respiratory tract infections (RTIs) in nonelderly adults, and factors moderating any such effects, are unclear. This systematic review and meta-analysis aimed to determine the effects of orally ingested probiotics, prebiotics, and synbiotics compared with placebo on RTI incidence, duration, and severity in nonelderly adults, and to identify potential sources of heterogeneity. Studies were identified by searching CENTRAL, PubMed, Scopus, and Web of Science up to December 2021. English-language, peer-reviewed publications of randomized, placebo-controlled studies that tested an orally ingested probiotic, prebiotic, or synbiotic intervention of any dose for ≥1 wk in adults aged 18-65 y were included. Results were synthesized using intention-to-treat and per-protocol random-effects meta-analysis. Heterogeneity was explored by subgroup meta-analysis and meta-regression. Risk of bias was assessed using the Cochrane risk-of-bias assessment tool for randomized trials version 2 (RoB2). Forty-two manuscripts reporting effects of probiotics (n = 38), prebiotics (n = 2), synbiotics (n = 1) or multiple -biotic types (n = 1) were identified (n = 9179 subjects). Probiotics reduced the risk of experiencing ≥1 RTI (relative risk = 0.91; 95% CI: 0.84, 0.98; P = 0.01), and total days (rate ratio = 0.77; 95% CI: 0.71, 0.83; P < 0.001), duration (Hedges' g = -0.23; 95% CI: -0.39, -0.08; P = 0.004), and severity (Hedges' g = -0.16; 95% CI: -0.29, -0.03; P = 0.02) of RTIs. Effects were relatively consistent across different strain combinations, doses, and durations, although reductions in RTI duration were larger with fermented dairy as the delivery matrix, and beneficial effects of probiotics were not observed in physically active populations. Overall risk of bias was rated as "some  concerns" for most studies. In conclusion, orally ingested probiotics, relative to placebo, modestly reduce the incidence, duration, and severity of RTIs in nonelderly adults. Physical activity and delivery matrix may moderate some of these effects. Whether prebiotic and synbiotic interventions confer similar protection remains unclear due to few relevant studies. This trial was registered at https://www.crd.york.ac.uk/prospero/ as CRD42020220213.