Anti-Glycation Properties of Zinc-Enriched Arthrospira platensis (Spirulina) Contribute to Prevention of Metaflammation in a Diet-Induced Obese Mouse Model.

Advanced glycation end products (AGEs) exert a key pathogenic role in the development of obesity and insulin resistance. Thanks to its abundance in bioactive compounds, the microalga Arthrospira platensis (spirulina, SP) is proposed as a nutritional supplement. Here, we investigated the potential anti-glycating properties of SP enriched with zinc (Zn-SP) and the following impact on diet-induced metabolic derangements. Thirty male C57Bl6 mice were fed a standard diet (SD) or a high-fat high-sugar diet (HFHS) for 12 weeks, and a subgroup of HFHS mice received 350 mg/kg Zn-SP three times a week. A HFHS diet induced obesity and glucose intolerance and increased plasma levels of pro-inflammatory cytokines and transaminases. Zn-SP administration restored glucose homeostasis and reduced hepatic dysfunction and systemic inflammation. In the liver of HFHS mice, a robust accumulation of AGEs was detected, paralleled by increased expression of the main AGE receptor (RAGE) and depletion of glyoxalase-1, whereas Zn-SP administration efficiently prevented these alterations reducing local pro-inflammatory responses. 16S rRNA gene profiling of feces and ileum content revealed altered bacterial community structure in HFHS mice compared to both SD and HFHS + Zn-SP groups. Overall, our study demonstrates relevant anti-glycation properties of Zn-SP which contribute to preventing AGE production and/or stimulate AGE detoxification, leading to the improvement of diet-related dysbiosis and metabolic derangements.

Collinsella aerofaciens as a predictive marker of response to probiotic treatment in non-constipated irritable bowel syndrome.

Probiotics are exploited for adjuvant treatment in IBS, but reliable guidance for selecting the appropriate probiotic to adopt for different forms of IBS is lacking. We aimed to identify markers for recognizing non-constipated (NC) IBS patients that may show significant clinical improvements upon treatment with the probiotic strain Lacticaseibacillus paracasei DG (LDG). To this purpose, we performed a post-hoc analysis of samples collected during a multicenter, double-blind, parallel-group, placebo-controlled trial in which NC-IBS patients were randomized to receive at least 24 billion CFU LDG or placebo capsules b.i.d. for 12 weeks. The primary clinical endpoint was the composite response based on improved abdominal pain and fecal type. The fecal microbiome and serum markers of intestinal (PV1 and zonulin), liver, and kidney functions were investigated. We found that responders (R) in the probiotic arm (25%) differed from non-responders (NR) based on the abundance of 18 bacterial taxa, including the families Coriobacteriaceae, Dorea spp. and Collinsella aerofaciens, which were overrepresented in R patients. These taxa also distinguished R (but not NR) patients from healthy controls. Probiotic intervention significantly reduced the abundance of these bacteria in R, but not in NR. Analogous results emerged for C. aerofaciens from the analysis of data from a previous trial on IBS with the same probiotic. Finally, C. aerofaciens was positively correlated with the plasmalemmal vesicle associated protein-1 (PV-1) and the markers of liver function. In conclusion, LDG is effective on NC-IBS patients with NC-IBS with a greater abundance of potential pathobionts. Among these, C. aerofaciens has emerged as a potential predictor of probiotic efficacy.

Fecal short-chain fatty acids in non-constipated irritable bowel syndrome: a potential clinically relevant stratification factor based on catabotyping analysis.

The gut microbiota is believed to be a critical factor in the pathogenesis of IBS, and its metabolic byproducts, such as short-chain fatty acids (SCFAs), are known to influence gut function and host health. Despite this, the precise role of SCFAs in IBS remains a topic of debate. In this study, we examined the bacterial community structure by 16S rRNA gene profiling and SCFA levels by UPLC-MS/MS in fecal samples from healthy controls (HC; n = 100) and non-constipated patients (IBS-D and IBS-M; NC-IBS; n = 240) enrolled in 19 hospitals in Italy. Our findings suggest a significant difference between the fecal microbiomes of NC-IBS patients and HC subjects, with HC exhibiting higher intra-sample biodiversity. Furthermore, we were able to classify non-constipated patients into two distinct subgroups based on their fecal SCFA levels (fecal catabotype "high" and "low"), each characterized by unique taxonomic bacterial signatures. Our results suggest that the fecal catabotype with higher SCFA levels may represent a distinct clinical phenotype of IBS that could have implications for its diagnosis and treatment. This study provides a new perspective on the intricate relationship between the gut microbiome and bowel symptoms in IBS, underscoring the importance of personalized strategies for its management.

Use of kefir-derived lactic acid bacteria for the preparation of a fermented soy drink with increased estrogenic activity.

Fermented foods are receiving growing attention for their health promoting properties. In particular, there is a growing demand for plant-based fermented foods as dairy alternatives. Considering that soy is a vegetal food rich in nutrients and a source of the phytoestrogen isoflavones, the aim of this study was to select safe food microorganisms with the ability to ferment a soy drink resulting in a final product with an increased estrogenic activity and improved functional properties. We used milk kefir grains, a dairy source of microorganisms with proven health-promoting properties, as a starting inoculum for a soymilk. After 14 passages of daily inoculum in fresh soy drink, we isolated four lactic acid bacterial strains: Lactotoccus lactis subsp. lactis K03, Leuconostc pseudomesenteroides K05, Leuconostc mesenteroides K09 and Lentilactobacillus kefiri K10. Isolated strains were proven to be safe for human consumption according to the assessment of their antibiotic resistance profile and comparative genomics. Furthermore, functional characterization of the bacterial strains demonstrated their ability to ferment sugars naturally present in soybeans and produce a creamy texture. In addition, we demonstrated, by means of a yeast-based bioluminescence reporter system, that the two strains belonging to the genus Leuconostoc increased the estrogenic activity of the soybean drink. In conclusion, the proposed application of the bacterial strains characterized in this study meets the growing demand of consumers for health-promoting vegetal food alternatives to dairy products.

Ready-To-Eat Rocket Salads as Potential Reservoir of Bacteria for the Human Microbiome.

Reportedly, Western-type diets may induce the loss of key microbial taxa within the gastrointestinal microbiota, promoting the onset of noncommunicable diseases. It was hypothesized that the consumption of raw vegetables could contribute to the maintenance of the intestinal microbial community structure. In this context, we explored bacteria associated with commercial rocket salads produced through different farming practices: traditional (conventional, organic, and integrated) and vertical farming. Viable counts of mesophilic bacteria and lactic acid bacteria (LAB) were performed on plate count agar (PCA) and de Man-Rogosa-Sharpe (MRS) agar at pH 5.7, whereas metataxonomics through 16S rRNA gene sequencing was used to profile total bacteria associated with rocket salads. We found that rocket salads from vertical farming had much fewer viable bacteria and had a bacterial community structure markedly different from that of rocket salads from traditional farming. Furthermore, although α- and ß-diversity analyses did not differentiate rocket samples according to farming techniques, several bacterial taxa distinguished organic and integrated from conventional farming salads, suggesting that farming practices could affect the taxonomic composition of rocket bacterial communities. LAB were isolated from only traditional farming samples and belonged to different species, which were variably distributed among samples and could be partly associated with farming practices. Finally, the INFOGEST protocol for in vitro simulation of gastrointestinal digestion revealed that several taxonomically different rocket-associated bacteria (particularly LAB) could survive gastrointestinal transit. This study suggests that commercial ready-to-eat rocket salads harbor live bacteria that possess the ability to survive gastrointestinal transit, potentially contributing to the taxonomic structure of the human gut microbiota. IMPORTANCE Western-type diets are composed of foods with a reduced amount of naturally occurring microorganisms. It was hypothesized that a microbe-depleted diet can favor the alteration of the human intestinal microbial ecosystem, therefore contributing to the onset of chronic metabolic and immune diseases currently recognized as the most significant causes of death in the developed world. Here, we studied the microorganisms that are associated with commercial ready-to-eat rocket salads produced through different farming practices. We showed that rocket salad (a widely consumed vegetal food frequently eaten raw) may be a source of lactic acid bacteria and other microbes that can survive gastrointestinal transit, potentially increasing the biodiversity of the intestinal microbiota. This deduction may be valid for virtually all vegetal foods that are consumed raw.

A mix of chlorogenic and caffeic acid reduces C/EBPß and PPAR-γ1 levels and counteracts lipid accumulation in macrophages.

PURPOSE: Chlorogenic acid (CGA) and caffeic acid (CA) are bioactive compounds in whole grains, berries, apples, some citrus fruits and coffee, which are hypothesized to promote health-beneficial effects on the cardiovascular system. This study aimed to evaluate the capacity of CGA and CA to reduce lipid accumulation in macrophages, recognized as a critical stage in the progression of atherosclerosis. Furtherly, the modulation of CCAAT/enhancer-binding protein ß (C/EBPß) and peroxisome proliferator-activated receptor- γ1 (PPAR-γ1), as transcription factors involved in lipid metabolism, was evaluated. METHODS: THP-1-derived macrophages were treated for 24 h with 0.03, 0.3, 3 and 30 µM of CGA and CA, tested alone or in combination, and a solution of oleic/palmitic acid (500 µM, 2:1 ratio). Lipid storage was assessed spectrophotometrically through fluorescent staining of cells with Nile red. C/EBPß and PPAR-γ1 mRNA and protein levels were evaluated by RT-PCR and enzyme-linked immunosorbent assay, respectively. RESULTS: The mix of CGA + CA (1:1 ratio) reduced lipid accumulation at all concentrations tested, except for the highest one. The greatest effect ( - 65%; p < 0.01) was observed at the concentration of 0.3 µM for each compound. The same concentration significantly (p < 0.01) downregulated C/EBPß and PPAR-γ1 gene expression and reduced their protein levels at 2 h and 24 h, respectively. CONCLUSION: The results indicate that the capacity of CGA + CA mix to reduce lipid storage in macrophages is mediated by a reduction in the expression of transcription factors C/EBPß and PPAR-γ1.

Bacterial DNAemia is associated with serum zonulin levels in older subjects.

The increased presence of bacteria in blood is a plausible contributing factor in the development and progression of aging-associated diseases. In this context, we performed the quantification and the taxonomic profiling of the bacterial DNA in blood samples collected from forty-three older subjects enrolled in a nursing home. Quantitative PCR targeting the 16S rRNA gene revealed that all samples contained detectable amounts of bacterial DNA with a concentration that varied considerably between subjects. Correlation analyses revealed that the bacterial DNAemia (expressed as concentration of 16S rRNA gene copies in blood) significantly associated with the serum levels of zonulin, a marker of intestinal permeability. This result was confirmed by the analysis of a second set of blood samples collected from the same subjects. 16S rRNA gene profiling revealed that most of the bacterial DNA detected in blood was ascribable to the phylum Proteobacteria with a predominance of the genus Pseudomonas. Several control samples were also analyzed to assess the influence of contaminant bacterial DNA potentially originating from reagents and materials. The data reported here suggest that para-cellular permeability of epithelial (and, potentially, endothelial) cell layers may play an important role in bacterial migration into the bloodstream. Bacterial DNAemia is likely to impact on several aspects of host physiology and could underpin the development and prognosis of various diseases in older subjects.

Surface Layer of Lactobacillus helveticus MIMLh5 Promotes Endocytosis by Dendritic Cells.

Surface layers (S-layers) are proteinaceous arrays covering the cell walls of numerous bacteria. Their suggested properties, such as interactions with the host immune system, have been only poorly described. Here, we aimed to elucidate the role of the S-layer from the probiotic bacterial strain Lactobacillus helveticus MIMLh5 in the stimulation of murine bone-marrow-derived dendritic cells (DCs). MIMLh5 induced greater production of interferon beta (IFN-ß), interleukin 10 (IL-10), and IL-12p70, compared to S-layer-depleted MIMLh5 (naked MIMLh5 [n-MIMLh5]), whereas the isolated S-layer was a poor immunostimulator. No differences in the production of tumor necrosis factor alpha (TNF-α) or IL-1ß were found. Inhibition of the mitogen-activated protein kinases JNK1/2, p38, and ERK1/2 modified IL-12p70 production similarly in MIMLh5 and n-MIMLh5, suggesting the induction of the same signaling pathways by the two bacterial preparations. Treatment of DCs with cytochalasin D to inhibit endocytosis before the addition of fluorescently labeled MIMLh5 cells led to a dramatic reduction in the proportion of fluorescence-positive DCs and decreased IL-12 production. Endocytosis and IL-12 production were only marginally affected by cytochalasin D pretreatment when fluorescently labeled n-MIMLh5 was used. Treatment of DCs with fluorescently labeled S-layer-coated polystyrene beads (Sl-beads) resulted in much greater uptake of beads, compared to noncoated beads. Prestimulation of DCs with cytochalasin D reduced the uptake of Sl-beads more than plain beads. These findings indicate that the S-layer plays a role in the endocytosis of MIMLh5 by DCs. In conclusion, this study provides evidence that the S-layer of L. helveticus MIMLh5 is involved in endocytosis of the bacterium, which is important for strong Th1-inducing cytokine production.IMPORTANCE Beneficial microbes may positively affect host physiology at various levels, e.g., by participating in immune system maturation and modulation, boosting defenses and dampening reactions, thus affecting the whole homeostasis. As a consequence, the use of probiotics is increasingly regarded as suitable for more extended applications for health maintenance, not only microbiota balancing. This implies a deep knowledge of the mechanisms and molecules involved in host-microbe interactions, for the final purpose of fine tuning the choice of a probiotic strain for a specific outcome. With this aim, studies targeted to the description of strain-related immunomodulatory effects and the identification of bacterial molecules responsible for specific responses are indispensable. This study provides new insights in the characterization of the food-origin probiotic bacterium L. helveticus MIMLh5 and its S-layer protein as a driver for the cross-talk with DCs.