Improvement of Intestinal Immune Cell Function by Lactic Acid Bacteria for Dairy Products

Activation of Antiviral Host Responses against Avian Influenza Virus and Remodeling of Gut Microbiota by rLAB Vector Expressing rIL-17A in Chickens

Low-pathogenic avian influenza virus (LPAIV) remains the most common subtype of type-A influenza virus that causes moderate to severe infection in poultry with significant zoonotic and pandemic potential. Due to high mutability, increasing drug resistance, and limited vaccine availability, the conventional means to prevent intra- or interspecies transmission of AIV is highly challenging. As an alternative to control AIV infections, cytokine-based approaches to augment antiviral host defense have gained significant attention. However, the selective application of cytokines is critical since unregulated expression of cytokines, particularly proinflammatory ones, can cause substantial tissue damage during acute phases of immune responses. Moreover, depending on the type of cytokine and its impact on intestinal microbiota, outcomes of cytokine-gut microflora interaction can have a critical effect on overall host defense against AIV infections. Our recent study demonstrated some prominent roles of chicken IL-17A (ChIL-17A) in regulating antiviral host responses against AIV infection, however, in an in vitro model. For more detailed insights into ChIL-17A function, in the present study, we investigated whether ChIL-17A-meditated elevated antiviral host responses can translate into effective immune protection against AIV infection in an in vivo system. Moreover, considering the role of gut health in fostering innate or local host responses, we further studied the contributory relationships between gut microbiota and host immunity against AIV infection in chickens. For this, we employed a recombinant lactic acid-producing bacterial (LAB) vector, Lactococcus lactis, expressing ChIL-17A and analyzed the in vivo functionality in chickens against an LPAIV (A/H9N2) infection. Our study delineates that mucosal delivery of rL. lactis expressing ChIL-17A triggers proinflammatory signaling cascades and can drive a positive shift in phylum Firmicutes, along with a marked decline in phylum Actinobacteriota and Proteobacteria, favoring effective antiviral host responses against AIV infection in chickens. We propose that ChIL-17A-mediated selective expansion of beneficial gut microbiota might form a healthy microbial community that augments the effective immune protection against AIV infections in chickens.

Lactococcus lactis subsp. cremoris C60 Upregulates Macrophage Function by Modifying Metabolic Preference in Enhanced Anti-Tumor Immunity

Lactococcus lactis subsp. cremoris C60 is a probiotic strain of lactic acid bacteria (LAB) which induces various immune modifications in myeloid lineage cells. These modifications subsequently regulate T cell function, resulting in enhanced immunity both locally and systemically. Here, we report that C60 suppresses tumor growth by enhancing macrophage function via metabolic alterations, thereby increasing adenosine triphosphate (ATP) production in a murine melanoma model. Intragastric (i.g.) administration of C60 significantly reduced tumor volume compared to saline administration in mice. The anti-tumor function of intratumor (IT) macrophage was upregulated in mice administered with C60, as evidenced by an increased inflammatory phenotype (M1) rather than an anti-inflammatory/reparative (M2) phenotype, along with enhanced antigen-presenting ability, resulting in increased tumor antigen-specific CD8+ T cells. Through this functional modification, we identified that C60 establishes a glycolysis-dominant metabolism, rather than fatty acid oxidation (FAO), in IT macrophages, leading to increased intracellular ATP levels. To address the question of why orally supplemented C60 exhibits functions in distal places, we found a possibility that bacterial cell wall components, which could be distributed throughout the body from the gut, may induce stimulatory signals in peripheral macrophages via Toll-like receptors (TLRs) signaling activation. Thus, C60 strengthens macrophage anti-tumor immunity by promoting a predominant metabolic shift towards glycolysis upon TLR-mediated stimulation, thereby increasing substantial energy production.

Assessment of stability and bioactive compounds in yogurt containing novel natural starter cultures with the ability to promote longevity in Caenorhabditis elegans

Yogurt represent one of the oldest fermented foods containing viable lactic acid bacteria and many bioactive compounds that could exhibit beneficial effects on human health and train our immune system to better respond to invading pathogens. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus are commonly used for yogurt preparation under controlled temperature and environmental conditions. In this study, we investigated probiotic features of S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains isolated from artisanal sour milk and yogurt by using Caenorhabditis elegans as an in vivo model system. Further, we evaluated content of total fat, saturated fatty acids, proteins, and lactose, as well as vitamins and AA of yogurt prepared from above-mentioned starter cultures during 21 d of storage at 4°C to get insights of final product stability. We showed that S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains applied in combination upregulated the expression of autophagy-related genes in C. elegans. Beside autophagy, we observed activation of TIR-1-dependent transcription of lysozyme-like antimicrobial genes involved in the immune defense of C. elegans. Upregulation of these genes strongly correlates with an increase in the longevity of the worms fed with yogurt culture bacteria. Further, we showed that yogurt prepared with S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21, as a final product, is rich with vitamin B2 and dominant AA known by their prolongevity properties. Taken together, our study pointed to the beneficial features of the tested starter cultures and yogurt and highlighted their potential to be used as a fermented food with added-value properties.

The Oral Delivery System of Modified GLP-1 by Probiotics for T2DM

The glucagon-like peptide-1 (GLP-1) is a peptide with incretin activity and plays an important role in glycemic control as well as the improvement of insulin resistance in type 2 diabetes mellitus (T2DM). However, the short half-life of the native GLP-1 in circulation poses difficulties for clinical practice. To improve the proteolytic stability and delivery properties of GLP-1, a protease-resistant modified GLP-1 (mGLP-1) was constructed with added arginine to ensure the structural integrity of the released mGLP-1 in vivo. The model probiotic Lactobacillus plantarum WCFS1 was chosen as the oral delivery vehicle with controllable endogenous genetic tools driven for mGLP-1 secretory constitutive expression. The feasibility of our design was explored in db/db mice which showed an improvement in diabetic symptoms related to decreased pancreatic glucagon, elevated pancreatic β-cell proportion, and increased insulin sensitivity. In conclusion, this study provides a novel strategy for the oral delivery of mGLP-1 and further probiotic transformation.

Effects of fermented dairy products on inflammatory biomarkers: A meta-analysis

AIM

Fermented dairy products (FDPs) are made from raw milk under the action of specific microorganisms by lactic acid bacteria fermentation or co-fermentation of lactic acid bacteria, bifidobacteria, and yeast. The aim of this study was to explore the effects of FDPs on inflammatory biomarkers.

DATA SYNTHESIS

A comprehensive search was conducted on four electronic databases, including PubMed, Web of Science, Embase, and the Cochrane Library. Finally, fourteen trials (15 arms) were included in this meta-analysis: yogurt (n = 9), fermented milk (n = 4), and kefir (n = 2). Additionally, the random effects model or fixed-effects model was used to pool the study results. Firstly, the analysis indicated that FDPs' supplementation decreased the levels of C-reactive protein (CRP) (SMD = -0.21; 95% CI: -0.40, -0.02; P = 0.033) and increased interferon-gamma (IFN-γ) levels (SMD = 0.12; 95% CI: 0.01, 0.23; P = 0.033). Furthermore, we obtained some statistically significant results in the following subgroups: CRP decreased in participants with metabolic diseases. IFN-γ increased in the intervention that lasted ≥12 weeks, Asian, yogurt, and healthy population. Finally, there was no significant effect on tumor necrosis factor-alpha, interleukin (IL)-6, IL-10, and IL-2.

CONCLUSIONS

FDPs reduced CRP and increased IFN-γ, but they had no effect on other inflammatory markers. The results showed that the consumption of FDPs was slightly associated with reduced inflammation, but because of the limited literature, these results should be interpreted with caution.

Research progress on the association between mastitis and gastrointestinal microbes in dairy cows and the effect of probiotics

Mastitis in dairy cows affects milk quality and thereby constrains the development of the dairy industry. A clear understanding of the pathogenesis of mastitis can help its treatment. Mastitis is caused by the invasion of pathogenic bacteria into the mammary gland through the mammary ducts. However, recent studies suggested that an endogenous entero-mammary pathway in dairy cattle might also be playing an important role in regulating mastitis. Also, probiotic intervention regulating host gut microbes has become an interesting tool to control mastitis. This review discusses the association of gastrointestinal microbes with mastitis and the mechanism of action of probiotics in dairy cows to provide new ideas for the management of mastitis in large-scale dairy farms.

Interleukin-17 Family Cytokines in Metabolic Disorders and Cancer

Interleukin-17 (IL-17) family cytokines are potent drivers of inflammatory responses. Although IL-17 was originally identified as a cytokine that induces protective effects against bacterial and fungal infections, IL-17 can also promote chronic inflammation in a number of autoimmune diseases. Research in the last decade has also elucidated critical roles of IL-17 during cancer development and treatment. Intriguingly, IL-17 seems to play a role in the risk of cancers that are associated with metabolic disorders. In this review, we summarize our current knowledge on the biochemical basis of IL-17 signaling, IL-17′s involvement in cancers and metabolic disorders, and postulate how IL-17 family cytokines may serve as a bridge between these two types of diseases.

Lactococcus lactis subsp. Cremoris C60 restores T Cell Population in Small Intestinal Lamina Propria in Aged Interleukin-18 Deficient Mice

Lactic acid bacteria (LAB), a major commensal bacterium in the small intestine, are well known beneficial bacteria which promote establishment of gut-centric immunity, such as anti-inflammation and anti-infection. In this report, we show that a LAB strain Lactococcus lactis subsp. Cremoris C60 possess an ability to activate antigen presenting cells, such as dendritic cells (DCs), and intestinal T cells which possibly support to maintain healthy intestinal immunological environment in aging process. We found that CD4+ T cells in the small intestine are dramatically decreased in aged Interleukin-18 knock out (IL-18KO) mice, associated with the impairment of IFN-γ production in the CD4+ T cells, especially in small intestinal lamina propria (LP). Surprisingly, heat killed-C60 (HK-C60) diet completely recovered the CD4+ T cells population and activity in SI-LP and over activated the population in Peyer's patches (PPs) of IL-18KO mice. The HK-C60 diet was effective approach not only to restore the number of cells, but also to recover IFN-γ production in the CD4+ T cell population in the small intestine of IL-18-deficient mice. As a possible cause in the age-associated impairment of CD4+ T cells activity in IL-18KO mice, we found that the immunological activity was downregulated in the IL-18-deficient DCs. The cytokines production and cellular activation markers expression were downregulated in the IL-18-deficient bone marrow derived dendritic cells (BMDCs) at the basal level, however, both activities were highly upregulated in HK-C60 stimulation as compared to those of WT cells. Antigen uptake was also attenuated in the IL-18-deficient BMDCs, and it was significantly enhanced in the cells as compared to WT cells in HK-60 stimulation. An in vitro antigen presentation assay showed that IFN-γ production in the CD4+ T cells was significantly enhanced in the culture of IL-18-deficient BMDCs compared with WT cells in the presence of HK-C60. Thus, we conclude that HK-C60 diet possesses an ability to restore T cells impairment in the small intestine of IL-18-deficient environment. In addition, the positive effect is based on the immunological modification of DCs function which directory influences into the promotion of effector CD4+ T cells generation in the small intestine.

Distinct Effects of Milk-Derived and Fermented Dairy Protein on Gut Microbiota and Cardiometabolic Markers in Diet-Induced Obese Mice

BACKGROUND

Recent meta-analyses suggest that the consumption of fermented dairy products reduces type 2 diabetes and cardiovascular disease (CVD) risk, although the underlying mechanisms remain unclear.

OBJECTIVE

We evaluated whether dairy protein products modulated gut microbiota and cardiometabolic features in mouse models of diet-induced obesity and CVD.

METHODS

Eight-week-old C57BL/6J wild-type (WT) and LDLr-/-ApoB100/100 (LRKO) male mice were fed for 12 and 24 wk, respectively, with a high-fat/high-sucrose diet [66% kcal lipids, 22% kcal carbohydrates (100% sucrose), 12% kcal proteins]. The protein sources of the 4 diets were 100% nondairy protein (NDP), or 50% of the NDP energy replaced by milk (MP), milk fermented by Lactobacillus helveticus (FMP), or Greek-style yogurt (YP) protein. Fecal 16S rRNA gene-based amplicon sequencing, intestinal gene expression, and glucose tolerance test were conducted. Hepatic inflammation and circulating adhesion molecules were measured by multiplex assays.

RESULTS

Feeding WT mice for 12 wk led to a 74% increase in body weight, whereas after 24 wk the LRKO mice had a 101.5% increase compared with initial body weight. Compared with NDP and MP, the consumption of FMP and YP modulated the gut microbiota composition in a similar clustering pattern, upregulating the Streptococcus genus in both genotypes. In WT mice, feeding YP compared with NDP increased the expression of genes involved in jejunal (Reg3b, 7.3-fold, P = 0.049) and ileal (Ocln, 1.7-fold, P = 0.047; Il1-β,1.7-fold, P = 0.038; Nos2, 3.8-fold, P = 0.018) immunity and integrity. In LRKO mice, feeding YP compared with MP improved insulin sensitivity by 65% (P = 0.039). In LRKO mice, feeding with FMP versus NDP attenuated hepatic inflammation (monocyte chemoattractant protein 1, 2.1-fold, P ˂ 0.0001; IL1-β, 5.7-fold, P = 0.0003; INF-γ, 1.7-fold, P = 0.002) whereas both FMP [vascular adhesion molecule 1 (VCAM1), 1.3-fold, P = 0.0003] and YP (VCAM1, 1.04-fold, P = 0.013; intracellular adhesion molecule 1, 1.4-fold, P = 0.028) decreased circulating adhesion molecules.

CONCLUSION

Both fermented dairy protein products reduce cardiometabolic risk factors in diet-induced obese mice, possibly by modulating the gut microbiota.

Prebiotic Driven Increases in IL-17A Do Not Prevent Campylobacter jejuni Colonization of Chickens

Worldwide Campylobacter jejuni is a leading cause of foodborne disease. Contamination of chicken meat with digesta from C. jejuni-positive birds during slaughter and processing is a key route of transmission to humans through the food chain. Colonization of chickens with C. jejuni elicits host innate immune responses that may be modulated by dietary additives to provide a reduction in the number of campylobacters colonizing the gastrointestinal tract and thereby reduce the likelihood of human exposure to an infectious dose. Here we report the effects of prebiotic galacto-oligosaccharide (GOS) on broiler chickens colonized with C. jejuni when challenged at either an early stage in development at 6 days of age or 20 days old when campylobacters are frequently detected in commercial flocks. GOS-fed birds had increased growth performance, but the levels of C. jejuni colonizing the cecal pouches were unchanged irrespective of the age of challenge. Dietary GOS modulated the immune response to C. jejuni by increasing cytokine IL-17A expression at colonization. Correspondingly, reduced diversity of the cecal microbiota was associated with Campylobacter colonization in GOS-fed birds. In birds challenged at 6 days-old the reduction in microbial diversity was accompanied by an increase in the relative abundance of Escherichia spp. Whilst immuno-modulation of the Th17 pro-inflammatory response did not prevent C. jejuni colonization of the intestinal tract of broiler chickens, the study highlights the potential for combinations of prebiotics, and specific competitors (synbiotics) to engage with the host innate immunity to reduce pathogen burdens.

Tracking of Intentionally Inoculated Lactic Acid Bacteria Strains in Yogurt and Probiotic Powder

The present work aimed at tracking intentionally inoculated lactic acid bacteria (LAB) strains in yogurt and probiotic powder. Leuconostoc (Leu.) mesenteroides (11251), Lactobacillus (L.) brevis (B151), and Lactobacillus plantarum (LB41^K) strains were tracked in yogurt, and L. plantarum (LB41^P) was tracked in a commercial probiotic powder. The yogurt was intentionally inoculated with the selected bacterial strains. Two types of yogurt with known and unknown bacterial pools were utilized. The standard 16S rRNA gene sequencing was used to evaluate the initial screening. The molecular typing tools, random amplified polymorphic DNA (RAPD), repetitive element palindromic PCR (rep-PCR), and comparative gene sequence analysis of selected housekeeping loci were used to track the inoculated dubious strains. Out of 30 random selections for each inoculation, the developed method identified seven (11251), nine (B151), and five (LB41^K) colonies in the yogurt. The validation was performed by identifying 7 colonies (LB41^P) out of 30 in the probiotic powder. The DNA banding profiles and the gene sequence alignments led to the identification of the correct inoculated strains. Overall, the study summarizes the use of molecular tools to identify the deliberately inoculated LAB strains. In conclusion, the proposed polyphasic approach effectively tracked the intentionally inoculated strains: Leu. mesenteroides, L. brevis, and L. plantarum (LB41^K) in yogurt and L. plantarum (LB41^P) in probiotic powder. The study demonstrates how to track industrially relevant misused LAB strains in marketable food products.

Gut Microbiota and IL-17A: Physiological and Pathological Responses

IL-17A is a cytokine which is produced by several immune and non-immune cells. The cytokine plays dual roles from protection from microbes and protection from pro-inflammatory based diseases to induction of the pro-inflammatory based diseases. The main mechanisms which lead to the controversial roles of IL-17A are yet to be clarified. Gut microbiota (GM) are the resident probiotic bacteria in the gastrointestinal tracts which have been introduced as a plausible regulator of IL-17A production and functions. This review article describes the recent information regarding the roles played by GM in determination of IL-17A functions outcome.

An introduction of the role of probiotics in human infections and autoimmune diseases

During the last decades, studies exploring the role of microorganisms inhabiting human body in different scenarios have demonstrated the great potential of modulating them to treat and prevent diseases. Among the most outstanding applications, probiotics have been used for over a century to treat infections and inflammation. Despite the beneficial role of other probiotics, Lactobacillus and Bifidobacterium species are the most frequently used, and have been effective as a therapeutic option in the treatment/prevention of dental caries, periodontal diseases, urogenital infections, and gastrointestinal infections. Additionally, as gastrointestinal tract harbors a great diversity of microbial species that directly or indirectly modulate host metabolism and immune response, the influence of intestinal microbiota, one of the targets of therapies using probiotics, on the biology of immune cells can be explored to treat inflammatory disorders or immune-mediated diseases. Thus, it is not surprising that probiotics have presented promising results in modulating human inflammatory diseases such as type 1 diabetes, multiple sclerosis, rheumatoid arthritis and inflammatory bowel disease, among others. Hence, the purpose of this review is to discuss the potential of therapeutic approaches using probiotics to constrain infection and development of inflammation on human subjects.

Impacts of Duck-Origin Parvovirus Infection on Cherry Valley Ducklings From the Perspective of Gut Microbiota

Duck-origin goose parvovirus (D-GPV) is the causative agent of beak atrophy and dwarfism syndrome (BADS), characterized by growth retardation, skeletal dysplasia, and persistent diarrhea. However, the pathogenic mechanism of D-GPV remains undefined. Here, we first reported the gut microbiome diversity of D-GPV infected Cherry Valley ducks. In the investigation for the influence of D-GPV infection on gut microbiota through a period of infection, we found that D-GPV infection caused gut microbiota dysbiosis by reducing the prevalence of the dominant genera and decreasing microbial diversity. Furthermore, exfoliation of the intestinal epithelium, proliferation of lymphocytes, up-regulated mRNA expression of pro-inflammatory TNF-α, IL-1β, IL-6, IL-17A, and IL-22 and down-regulated mRNA expression of anti-inflammatory IL-10 and IL-4 occurred when D-GPV targeted in cecal epithelium. In addition, the content of short chain fatty acids (SCFAs) in cecal contents was significantly reduced after D-GPV infection. Importantly, the disorder of pro-inflammatory and anti-inflammatory cytokines was associated with the decrease of SCFAs-producing bacteria and the enrichment of opportunistic pathogens. Collectively, the decrease of SCFAs and the enrichment of pathogen-containing gut communities promoted intestinal inflammatory injury. These results may provide a new insight that target the gut microbiota to understand the progression of BADS disease and to research the pathogenic mechanism of D-GPV.

Study of bacterial and fungal community structures in traditional koumiss from Inner Mongolia

Koumiss is notable for its nutritional functions, and microorganisms in koumiss determine its versatility. In this study, the bacterial and fungal community structures in traditional koumiss from Inner Mongolia, China, were investigated. Our results demonstrated that 6 bacterial phyla represented by 126 genera and 49 species and 3 fungal phyla represented by 59 genera and 57 species were detected in 11 samples of artisanal koumiss. Among them, Lactobacillus was the predominant genus of bacterium, and Kluyveromyces and Saccharomyces dominated at the fungal genus level. In addition, there were no differences in the bacterial and fungal richness and diversity of koumiss from 3 neighboring administrative divisions in Inner Mongolia, and the bacterial and fungal community structures (the varieties and relative abundance of bacterial and fungal genera and species) were clearly distinct in individual samples. This study provides a comprehensive understanding of the bacterial and fungal population profiles and the predominant genus and species, which would be beneficial for screening, isolation, and culture of potential probiotics to simulate traditional fermentation of koumiss for industrial and standardized production in the future.

Origination, change, and modulation of geriatric disease-related gut microbiota during life

The age-related changes in the diversity and composition of the gut microbiota are well described in recent studies. These changes have been suggested to be influenced by age-associated weakening of the immune system and low-grade chronic inflammation, resulting in numerous age-associated pathological conditions. Gut microbiota homeostasis is important throughout the life of the host by providing vital functions to regulate various immunological functions and homeostasis. Based on published results, we summarize the relationship between the gut microbiota and aging-related diseases, especially Parkinson's disease, immunosenescence, rheumatoid arthritis, bone loss, and metabolic syndrome. The change in composition of the gut microbiota and gut ecosystem during life and its influence on the host immunologic and metabolic phenotype are also analyzed to determine factors that affect aging-related diseases. Approaches to maintain host health and prevent or cure geriatric diseases are also discussed.

Pharmaceutical significance of Leuconostoc mesenteroides KS-TN11 isolated from Nile Tilapia, Oreochromis niloticus

Aquatic animals are known for their myriad of beneficial bacteria with diverse biologically active compounds. The current study was aimed to isolate and characterize potentially beneficial lactic acid bacteria from Nile Tilapia and evaluate their pharmaceutical applications. The fish samples were dissected and stomach, intestine, and gills were collected and serially diluted for the isolation of lactic acid bacteria (LAB) on BCP agar media. Identification of isolate was carried by biochemical and molecular characterization using API kit and 16S rRNA gene sequencing analysis, respectively. Further, KS-TN11 was assessed for α-glucosidase inhibitory potential using the chromogenic method. A lactic acid bacterium KS-TN11 was isolated from the stomach of Nile Tilapia and identified as Leuconostoc mesenteroides. Effect of KS-TN11 on lipid accumulation in adipocytes was done by using Oil Red O staining. The isolate showed strong antibacterial activity against a number of pathogenic bacteria in vitro. In addition, L. mesenteroides KS-TN11 KS-TN11 (50 mg/ml and 100 mg/ml) tends to inhibit adipogenesis in 3T3-L1 adipocytes and thus may have possible anti-obesity effects. Moreover, L. mesenteroides KS-TN11 exhibited substantial α–glucosidase inhibitory activities by 41.33% at 50 mg/ml and 64% at 100 mg/ml, respectively. The bacterium showed potent antibacterial activity against a number of pathogenic bacteria; in addition to alpha-glucosidase activity, and inhibition of lipid accumulation in 3T3-L1 cell line. These results reinforce KS-TN11 as a novel bacterium with an impending pharmaceutical application.

Caloric restriction promotes rapid expansion and long-lasting increase of Lactobacillus in the rat fecal microbiota

Previous studies indicated that caloric restricted diet enables to lower significantly the risk of cardiovascular and metabolic diseases. In experimental animal models, life-long lasting caloric restriction (CR) was demonstrated to induce changes of the intestinal microbiota composition, regardless of fat content and/or exercise. To explore the potential impact of short and long-term CR treatment on the gut microbiota, we conducted an analysis of fecal microbiota composition in young and adult Fisher 344 rats treated with a low fat feed under ad libitum (AL) or CR conditions (70%). We report here significant changes of the rat fecal microbiota that arise rapidly in young growing animals after short-term administration of a CR diet. In particular, Lactobacillus increased significantly after 8 weeks of CR treatment and its relative abundance was significantly higher in CR vs AL fed animals after 36 weeks of dietary intervention. Taken together, our data suggest that Lactobacillus intestinal colonization is hampered in AL fed young rats compared to CR fed ones, while health-promoting CR diet intervention enables the expansion of this genus rapidly and persistently up to adulthood.

Efficacy and Safety of a Multistrain Probiotic Formulation Depends from Manufacturing

Background

Variability in probiotics manufacturing may affect their properties, with potential implications for their efficacy and safety. This is of particular concern with probiotic products destined for use in patients with serious medical conditions, including human immunodeficiency virus (HIV) infection. The purpose of the study was to carry out a series of experiments comparing the properties of the US-made probiotic formulation originally commercialized under the brand name VSL#3^®, with those of the Italian-made formulation now commercialized under the same name. The US-made formulation has previously shown beneficial effects at the intestinal and neurological levels in HIV-infected subjects as well as in patients with inflammatory bowel diseases and hepatic encephalopathy.

Methods

Eleven subjects receiving combined antiretroviral therapy for HIV-1 were treated for 6 months with the US-made VSL#3 formulation. At baseline and 6 months, T-cells were analyzed for phenotype and activation markers, and fecal samples were analyzed for bifidobacteria, lactobacilli, and their metabolites. The fecal metabolome was assessed using ¹H-NMR spectroscopy. Production of metabolites of interest by bacteria obtained from sachets of the two formulations was compared in vitro and their effects on a rat intestinal epithelial cell line (IEC-6) were assessed. Particular attention was paid to the metabolite 1,3-dihydroxyacetone (DHA).

Results

At 6 months, fecal samples showed a significant increase in the specific bacterial genera contained in the probiotic supplement. Immune activation was reduced as shown by a significant reduction in the percentage of CD4⁺CD38⁺HLA-DR⁺ T-cells at 6 months. Fecal concentrations of DHA decreased significantly. In vitro, significant differences in the production and metabolism of DHA were found between bacteria from the US-made and Italian-made formulations: the US-made formulation was able to metabolize DHA whereas the bacteria in the Italian-made formulation were producing DHA. DHA reduced the viability of Streptococcus thermophilus, reduced IEC-6 cell viability in a dose-dependent manner, and also led to a lower rate of repair to scratched IEC-6 cell monolayer.

Conclusion

Our data, in conjunction with previously published findings, confirm that the new Italian-made formulation of VSL#3^® is different from the previous US-made VSL#3 and therefore its efficacy and safety in HIV-infected subjects is still unproven.