Using an Aluminum Hydroxide-Chitosan Matrix Increased the Vaccine Potential and Immune Response of Mice against Multi-Drug-Resistant Acinetobacter baumannii.

Acinetobacter baumannii is a Gram-negative, immobile, aerobic nosocomial opportunistic coccobacillus that causes pneumonia, septicemia, and urinary tract infections in immunosuppressed patients. There are no commercially available alternative antimicrobials, and multi-drug resistance is an urgent concern that requires emergency measures and new therapeutic strategies. This study evaluated a multi-drug-resistant A. baumannii whole-cell vaccine, inactivated and adsorbed on an aluminum hydroxide-chitosan (mAhC) matrix, in an A. baumannii sepsis model in immunosuppressed mice by cyclophosphamide (CY). CY-treated mice were divided into immunized, non-immunized, and adjuvant-inoculated groups. Three vaccine doses were given at 0D, 14D, and 28D, followed by a lethal dose of 4.0 × 108 CFU/mL of A. baumannii. Immunized CY-treated mice underwent a significant humoral response, with the highest IgG levels and a higher survival rate (85%); this differed from the non-immunized CY-treated mice, none of whom survived (p < 0.001), and from the adjuvant group, with 45% survival (p < 0.05). Histological data revealed the evident expansion of white spleen pulp from immunized CY-treated mice, whereas, in non-immunized and adjuvanted CY-treated mice, there was more significant organ tissue damage. Our results confirmed the proof-of-concept of the immune response and vaccine protection in a sepsis model in CY-treated mice, contributing to the advancement of new alternatives for protection against A. baumannii infections.

Oral Angiotensin-(1-7) Peptide Modulates Intestinal Microbiota Improving Metabolic Profile in Obese Mice.

BACKGROUND: Obesity is a serious health problem that dysregulate Renin-Angiotensin System (RAS) and intestinal microbiota. OBJECTIVE: The present study aimed to evaluate the Angiotensin-(1-7) [ANG-(1-7)] oral formulation effects on obese mice intestinal microbiota. METHODS: Mice were divided into four groups: obese and non-obese treated with ANG-(1-7) and obese and non-obese without ANG-(1-7) during four weeks. RESULTS: We observed a significant decrease in the fasting plasma glucose, total cholesterol, triglycerides, and Low-density lipoprotein levels and increased High-density lipoprotein in animals treated with ANG-(1-7). The histological analysis showed intestinal villi height reduction in mice treated with ANG-(1-7). Additionally, increased Bacteroidetes and decreased Firmicutes (increased Bacteroidetes/ Firmicutes ratio) and Enterobacter cloacae populations were observed in the High-Fat Diet + ANG-(1-7) group. Receptor toll-like 4 (TLR4) intestinal mRNA expression was reduced in the HFD+ANG-(1-7) group. Finally, the intestinal expression of the neutral amino acid transporter (B0AT1) was increased in animals treated with ANG-(1-7), indicating a possible mechanism associated with tryptophan uptake. CONCLUSION: The results of the present study suggest for the first time an interaction between oral ANG-(1-7) and intestinal microbiota modulation.

Oral Probiotic Bifidobacterium Longum Supplementation Improves Metabolic Parameters and Alters the Expression of the Renin-Angiotensin System in Obese Mice Liver.

BACKGROUND: Obesity and non-alcoholic fatty liver disease (NAFLD) have been increasing at an alarming rate worldwide. Bifidobacterium longum (BL), a common member of the human gut microbiota, has important health benefits through several mechanisms. OBJECTIVES: We evaluated the BL supplementation effects on body metabolism and renin-angiotensin components hepatic expression in mice fed a high-fat diet. METHODS: Thirty-two male mice were divided into four groups: standard diet + placebo (ST), standard diet + Bifidobacterium longum (ST + BL), high-fat diet + placebo (HFD) and high-fat diet + Bifidobacterium longum (HFD + BL). Following the obesity induction period, the ST + BL and HFD + BL groups were supplemented with Bifidobacterium longum for 4 weeks. Then, body, biochemical, histological and molecular parameters were evaluated. RESULTS: HFD + BL mice had a significant decrease in adipose tissue mass and blood glucose levels, as well as a significant reduction in blood glucose during an intraperitoneal glucose tolerance test. The treatment also resulted in reduced levels of total cholesterol and hepatic fat accumulation. Moreover, we observed an increase in angiotensin converting enzyme 2 (ACE2) and Mas receptor (MASR) expression levels in BL-treated obese mice. CONCLUSIONS: These data demonstrate that BL may have the potential to prevent obesity and NAFLD by modulating the mRNA expression of renin-angiotensin system components.

Inactivated alpha toxin from Clostridium novyi type B in nano-emulsion protect partially protects Swiss mice from lethal alpha toxin challenge.

Nano-emulsions are promising carriers for antigen delivery. Here, we evaluated the efficacy of a water-oil nano-emulsion containing concentrated, inactivated Clostridium novyi (C. novyi) type B supernatant culture (nano-iCnB) in protecting Swiss mice against a lethal dose of alpha toxin concentrated extract. Proteins were confirmed in the nano-iCnB and their stabilities were determined according physical parameters such as Zeta Potential (ZP). Biochemical, hematological parameters and morphological appearance of liver, spleen and thigh muscle alterations were examined to determine the safety of the compound. Partial protection against lethal doses was achieved in immunized mice despite low IgG titers. These data suggest that our nano-emulsion is a simple and efficient method of promoting antigen delivery for toxin-related diseases.

The role of the angiotensin II type I receptor blocker telmisartan in the treatment of non-alcoholic fatty liver disease: a brief review.

Non-alcoholic fatty liver disease (NAFLD) is currently considered an important component of metabolic syndrome (MetS). The spectrum of NAFLD includes conditions that range from simple hepatic steatosis to non-alcoholic steatohepatitis. NAFLD is correlated with liver-related death and is predicted to be the most frequent indication for liver transplantation by 2030. Insulin resistance is directly correlated to the central mechanisms of hepatic steatosis in NAFLD patients, which is strongly correlated to the imbalance of the renin-angiotensin system, that is involved in lipid and glucose metabolism. Among the emerging treatment approaches for NAFLD is the anti-hypertensive agent telmisartan, which has positive effects on liver, lipid, and glucose metabolism, especially through its action on the renin-angiotensin system, by blocking the ACE/AngII/AT1 axis and increasing ACE2/Ang(1-7)/Mas axis activation. However, treatment with this drug is only recommended for patients with an established indication for anti-hypertensive therapy. Thus, there is an increased need for large randomized controlled trials with the aim of elucidating the effects of telmisartan on liver disease, especially NAFLD. From this perspective, the present review aims to provide a brief examination of the pathogenesis of NAFLD/NASH and the role of telmisartan on preventing liver disorders and thus to improve the discussion on potential therapies.

Effects of Dietary Macronutrient Composition on FNDC5 and Irisin in Mice Skeletal Muscle.

BACKGROUND: Fibronectin type III domain containing 5 (FNDC5) and its protein product Irisin are therapeutic targets for obesity-associated disorders. Irisin plays an important role in energy regulation, inducing browning of white adipocytes, and improving obesity. We aimed to investigate the association between muscle Irisin expression and dietary quality. METHODS: Twenty-eight female mice were divided into four groups and fed the following experimental diets for 60 days: standard diet (SD), high-carbohydrate diet (HCD), high-fat diet (HFD), and high-protein diet (HPD). We evaluated body weight, food intake, serum total cholesterol, triacylglycerol, and glucose. We also performed glucose tolerance and insulin sensitivity tests. Expression of FNDC5 was evaluated by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) of soleus muscle. Western blot was used to assess Irisin protein expression. RESULTS: The major finding of the present study was that HFD and HCD were associated with a downregulation of FNDC5. In addition to these results, we noted a significant reduction in skeletal muscle Irisin level. HPD prevented reductions of both FNDC5 and Irisin levels, as well as increased brown adipose tissue, compared to the control group. CONCLUSIONS: In conclusion, we observed that the HPD type of diet can change both FNDC5 expression and Irisin levels. Thus, the HPD might be the most appropriate diet to achieve high amounts of Irisin, a target molecule for the treatment of obesity and its co-morbidities.

Modified toxin-binding inhibition (ToBI) test for epsilon antitoxin determination in serum of immunized rabbits.

The aim of the present study was to evaluate and standardize the ToBI test in vitro as a substitute for the serum neutralization test in mice for quality control of clostridial vaccines. The ToBI test in vitro was used to evaluate 40 serum samples of known antibody content, obtained from rabbits immunized against clostridiosis with experimental vaccine. The correlation between epsilon antitoxin titers in rabbit sera, determined by the ToBI test and serum neutralization in mice, ranged from 0.222% to 0.452% in polyvalent vaccines and from 0.154% to 0.387% in monovalent vaccines. Interplate coefficients of variation were not significant, reaching 0.350% in polyvalent vaccines and 0.400% in monovalent vaccines, indicating high homogeneity. In conclusion, the ToBI test in vitro is suitable for assessing the potency of clostridial vaccines and may be used as an alternative method able to replace current in vivo tests.

Modified toxin-binding inhibition (ToBI) test for epsilon antitoxin determination in serum of immunized rabbits

The aim of the present study was to evaluate and standardize the ToBI test in vitro as a substitute for the serum neutralization test in mice for quality control of clostridial vaccines. The ToBI test in vitro was used to evaluate 40 serum samples of known antibody content, obtained from rabbits immunized against clostridiosis with experimental vaccine. The correlation between epsilon antitoxin titers in rabbit sera, determined by the ToBI test and serum neutralization in mice, ranged from 0.222% to 0.452% in polyvalent vaccines and from 0.154% to 0.387% in monovalent vaccines. Interplate coefficients of variation were not significant, reaching 0.350% in polyvalent vaccines and 0.400% in monovalent vaccines, indicating high homogeneity. In conclusion, the ToBI test in vitro is suitable for assessing the potency of clostridial vaccines and may be used as an alternative method able to replace current in vivo tests.