Adlercreutzia equolifaciens Is an Anti-Inflammatory Commensal Bacterium with Decreased Abundance in Gut Microbiota of Patients with Metabolic Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) affects about 20-40% of the adult population in high-income countries and is now a leading indication for liver transplantation and can lead to hepatocellular carcinoma. The link between gut microbiota dysbiosis and NAFLD is now clearly established. Through analyses of the gut microbiota with shotgun metagenomics, we observe that compared to healthy controls, Adlercreutzia equolifaciens is depleted in patients with liver diseases such as NAFLD. Its abundance also decreases as the disease progresses and eventually disappears in the last stages indicating a strong association with disease severity. Moreover, we show that A. equolifaciens possesses anti-inflammatory properties, both in vitro and in vivo in a humanized mouse model of NAFLD. Therefore, our results demonstrate a link between NAFLD and the severity of liver disease and the presence of A. equolifaciens and its anti-inflammatory actions. Counterbalancing dysbiosis with this bacterium may be a promising live biotherapeutic strategy for liver diseases.

Design of a new lyoprotectant increasing freeze-dried Lactobacillus strain survival to long-term storage.

BACKGROUND: Stabilization of freeze-dried lactic acid bacteria during long-term storage is challenging for the food industry. Water activity of the lyophilizates is clearly related to the water availability and maintaining a low aw during storage allows to increase bacteria viability. The aim of this study was to achieve a low water activity after freeze-drying and subsequently during long-term storage through the design of a lyoprotectant. Indeed, for the same water content as sucrose (commonly used lyoprotectant), water activity is lower for some components such as whey, micellar casein or inulin. We hypothesized that the addition of these components in a lyoprotectant, with a higher bound water content than sucrose would improve lactobacilli strains survival to long-term storage. Therefore, in this study, 5% whey (w/v), 5% micellar casein (w/v) or 5% inulin (w/v) were added to a 5% sucrose solution (w/v) and compared with a lyoprotectant only composed of 5% sucrose (w/v). Protective effect of the four lyoprotectants was assessed measuring Lactiplantibacillus plantarum CNCM I-4459 survival and water activity after freeze-drying and during 9 months storage at 25 °C. RESULTS: The addition whey and inulin were not effective in increasing Lactiplantibacillus plantarum CNCM I-4459 survival to long-term-storage (4 log reduction at 9 months storage). However, the addition of micellar casein to sucrose increased drastically the protective effect of the lyoprotectant (3.6 log i.e. 0.4 log reduction at 9 months storage). Comparing to a lyoprotectant containing whey or inulin, a lyoprotectant containing micellar casein resulted in a lower water activity after freeze-drying and its maintenance during storage (0.13 ± 0.05). CONCLUSIONS: The addition of micellar casein to a sucrose solution, contrary to the addition of whey and inulin, resulted in a higher bacterial viability to long-term storage. Indeed, for the same water content as the others lyoprotectants, a significant lower water activity was obtained with micellar casein during storage. Probably due to high bound water content of micellar casein, less water could be available for chemical degradation reactions, responsible for bacterial damages during long-term storage. Therefore, the addition of this component to a sucrose solution could be an effective strategy for dried bacteria stabilization during long-term storage.

Increased Survival of Lactococcus lactis Strains Subjected to Freeze-Drying after Cultivation in an Acid Medium: Involvement of Membrane Fluidity Cultivation in Acid Medium to Improve Bacterial Survival of Freeze-Drying.

RESEARCH BACKGROUND: Freeze-drying is the most widely used dehydration process in the food industry for the stabilization of bacteria. Studies have shown the effectiveness of an acid prestress in increasing the resistance of lactic acid bacteria to freeze-drying. Adaptation of bacteria to an acid stress is based on maintaining the properties of the plasma membrane. Indeed, the fatty acid composition of the membrane of lactic acid bacteria is often changed after an acid prestress. However, few studies have measured membrane fluidity after an acid stress during lactic acid bacterial strain cultivation. EXPERIMENTAL APPROACH: In order to use two pH profiles, the strains Lactococcus lactis NCDO 712 and NZ9000 were cultivated in two media, without any pH control. The two pH profiles obtained were representative of the initial medium composition, medium buffering properties and strain metabolism. Absorbance at 600 nm and pH were measured during bacterial cultivation. Then, the two strains were freeze-dried and their survival rates determined. Membrane fluidity was evaluated by fluorescence anisotropy measurements using a spectrofluorometer. RESULTS AND CONCLUSIONS: Cultivation under more acidic conditions significantly increased the survival during freeze-drying (p<0.05, ANOVA) of both strains. Moreover, in both strains of L. lactis, a more acidic condition during cultivation significantly increased membrane fluidity (p<0.05, ANOVA). Our results revealed that cultivation under such conditions, fluidifies the membrane and allows a better survival during freeze-drying of the two L. lactis strains. A more fluid membrane can facilitate membrane deformation and lateral reorganization of membrane components, critical for the maintenance of cellular integrity during dehydration and rehydration. NOVELTY AND SCIENTIFIC CONTRIBUTION: A better understanding of the involvement of membrane properties, especially of membrane fluidity, in bacterial resistance to dehydration is provided in this study.

Beneficial Effects of Lactobacilli Species on Intestinal Homeostasis in Low-Grade Inflammation and Stress Rodent Models and Their Implication in the Modulation of the Adhesive Junctional Complex.

Intestinal barrier integrity is essential in order to maintain the homeostasis of mucosal functions and efficient defensive reactions against chemical and microbial challenges. An impairment of the intestinal barrier has been observed in several chronic diseases. The gut microbiota and its impact on intestinal homeostasis is well described and numerous studies suggest the ability of some probiotic strains to protect the intestinal epithelial integrity and host homeostasis. In this work, we aimed to assess the beneficial effects of three Lactobacillus strains (Lacticaseibacillus rhamnosus LR04, Lacticaseibacillus casei LC03, and Lactiplantibacillus plantarum CNCM I-4459) and their mechanism of action in low-grade inflammation or neonatal maternal separation models in mice. We compared the impact of these strains to that of the well-known probiotic Lacticaseibacillus rhamnosus GG. Our results demonstrated that the three strains have the potential to restore the barrier functions by (i) increasing mucus production, (ii) restoring normal permeability, and (iii) modulating colonic hypersensitivity. Moreover, gene expression analysis of junctional proteins revealed the implication of Claudin 2 and Cingulin in the mechanisms that underlie the interactions between the strains and the host. Taken together, our data suggest that LR04, CNCM I-4459, and LC03 restore the functions of an impaired intestinal barrier.

Evaluation of the Probiotic Properties and the Capacity to Form Biofilms of Various Lactobacillus Strains.

Over the last 20 years, Lactobacillus species inhabiting the gastrointestinal tract (GIT) have received much attention, and their health-promoting properties are now well-described. Probiotic effects cannot be generalized, and their uses cover a wide range of applications. It is thus important to proceed to an accurate selection and evaluation of probiotic candidates. We evaluate the probiotic potential of six strains of Lactobacillus in different in vitro models representing critical factors of either survival, efficacy, or both. We characterized the strains for their ability to (i) modulate intestinal permeability using transepithelial electrical resistance (TEER), (ii) form biofilms and resist stressful conditions, and (iii) produce beneficial host and/or bacteria metabolites. Our data reveal the specificity of Lactobacillus strains to modulate intestinal permeability depending on the cell type. The six isolates were able to form spatially organized biofilms, and we provide evidence that the biofilm form is beneficial in a strongly acidic environment. Finally, we demonstrated the ability of the strains to produce γ-aminobutyric acid (GABA) that is involved in the gut-brain axis and beneficial enzymes that promote the bacterial tolerance to bile salts. Overall, our study highlights the specific properties of Lactobacillus strains and their possible applications as biofilms.

How Safe Is Ginger Rhizome for Decreasing Nausea and Vomiting in Women during Early Pregnancy?

Ginger, Zingiber officinale Roscoe, is increasingly consumed as a food or in food supplements. It is also recognized as a popular nonpharmacological treatment for nausea and vomiting of pregnancy (NVP). However, its consumption is not recommended by all countries for pregnant women. Study results are heterogeneous and conclusions are not persuasive enough to permit heath care professionals to recommend ginger safely. Some drugs are also contraindicated, leaving pregnant women with NVP with few solutions. We conducted a review to assess effectiveness and safety of ginger consumption during early pregnancy. Systematic literature searches were conducted on Medline (via Pubmed) until the end of December 2017. For the evaluation of efficacy, only double-blind, randomized, controlled trials were included. For the evaluation of the safety, controlled, uncontrolled, and pre-clinical studies were included in the review. Concerning toxicity, none can be extrapolated to humans from in vitro results. In vivo studies do not identify any major toxicities. Concerning efficacy and safety, a total of 15 studies and 3 prospective clinical studies have been studied. For 1 g of fresh ginger root per day for four days, results show a significant decrease in nausea and vomiting and no risk for the mother or her future baby. The available evidence suggests that ginger is a safe and effective treatment for NVP. However, beyond the ginger quantity needed to be effective, ginger quality is important from the perspective of safety.