Metformin acts in the gut and induces gut-liver crosstalk.

Metformin is the most prescribed drug for DM2, but its site and mechanism of action are still not well established. Here, we investigated the effects of metformin on basolateral intestinal glucose uptake (BIGU), and its consequences on hepatic glucose production (HGP). In diabetic patients and mice, the primary site of metformin action was the gut, increasing BIGU, evaluated through PET-CT. In mice and CaCo2 cells, this increase in BIGU resulted from an increase in GLUT1 and GLUT2, secondary to ATF4 and AMPK. In hyperglycemia, metformin increased the lactate (reducing pH and bicarbonate in portal vein) and acetate production in the gut, modulating liver pyruvate carboxylase, MPC1/2, and FBP1, establishing a gut-liver crosstalk that reduces HGP. In normoglycemia, metformin-induced increases in BIGU is accompanied by hypoglycemia in the portal vein, generating a counter-regulatory mechanism that avoids reductions or even increases HGP. In summary, metformin increases BIGU and through gut-liver crosstalk influences HGP.

Proton Pump Inhibitor Pantoprazole Modulates Intestinal Microbiota and Induces TLR4 Signaling and Fibrosis in Mouse Liver.

Proton pump inhibitors (PPIs) are one of the most prescribed drugs around the world. PPIs induce microbiota modulation such as obesity both in humans and in animal models. However, since PPIs can induce microbiota modulation despite the absence of a high-fat diet or weight gain, it is an interesting model to correlate microbiota modulation with the establishment of non-alcoholic fatty liver disease (NAFLD). We investigated the effect of pantoprazole treatment on TLR4 signaling and liver histology in C57BL/6J mice for 60 days, trying to correlate microbiota modulation with some aspects of liver injury. We performed glucose (GTT) and insulin (ITT) tolerance tests, serum lipopolysaccharide (LPS) dosage, liver histology, liver and intestine extraction for Western blot and qPCR. Fecal microbiota were investigated via metagenomics. Chronic treatment with pantoprazole induced microbiota modulation and impaired ileum barrier integrity, without an association with insulin resistance. Furthermore, increased circulating LPS and increased Toll-like receptor 4 (TLR4) and TGFß downstream signaling may have an important role in the development of the observed liver microvesicular steatosis and fibrosis. Finally, this model of PPI-induced changes in microbiota might be useful to investigate liver microvesicular steatosis and fibrosis.

Carcinogenesis and Bacillus Calmette-Guérin (BCG) Intravesical Treatment of Non-Muscle-Invasive Bladder Cancer under Tryptophan and Thymine Supplementation.

PURPOSE: Evaluate tryptophan and thymine (TT) impact on carcinogenesis and intravesical BCG bladder cancer treatment. METHODS: After identification of TT in vitro inhibitory effect in multiple cancer cell cultures, bladder cancer animal model was induced by MNU intravesical instillations and randomized into four groups: Control (n = 9), BCG (n = 9), TT (n = 7), and BCG + TT (n = 8). BCG groups received intravesical 106 CFU BCG in 0.2 ml saline for 6 consecutive weeks and TT groups received 1 g/kg (1:1) of TT via daily gavage. After 15 wk of protocol, animals were euthanized and the urinary bladders submitted to histopathology, immunohistochemistry, and Western blotting. RESULTS: Urothelial cancer was identified in 100%, 85.7%, 44.5%, and 37.5% of Control, TT, BCG, and BCG + TT groups, respectively. Cell proliferation marked by nuclear Ki-67 was higher in the Control compared to animals in the other groups (P = 0.03). BCG, TT, and BCG + TT groups showed proliferative cell decline and TLR4/5 labeling increase in the urothelium. BCG decreased the urothelial VEGF labeling, even in TT association. CONCLUSION: TT inhibit urothelial carcinogenesis and potentiate the intravesical BCG in the treatment of bladder cancer by reducing cell proliferation and activating TLRs.

Boosting bladder cancer treatment by intravesical nitazoxanide and bacillus calmette-guérin association.

PURPOSE: Nitazoxanide (NTZ) has shown a promising antitumoral effect, the current study compared the anti-neoplastic effects of intravesical NTZ and BCG plus NTZ in NMIBC animal model. METHODS: 30 rats, Fisher 344 were instilled with 4 intravesical doses of 1.5 mg/kg of N-methyl-N-nitrosourea (MNU) every 15 days for BC induction. The animals were divided into 3 groups (Group BCG 106 UFC - 1 mg of BCG; Group NTZ - 300 mg/kg of NTZ; Group NTZ + BCG - simultaneous treatment of BCG and NTZ) and received weekly intravesical treatment for 6 consecutive weeks. Animals were submitted to ultrasound imaging and euthanasia, their bladders were collected and histopathological, immunohistochemical tests (ki67 e c-Myc) and Western Blotting (PI3K, mTOR, and p-4E-BP) were performed. RESULTS: Histopathological tests showed 66.67%, 62.5% and 37.5% incidence of BC in animals treated with BCG, NTZ, and NTZ + BCG, respectively. Nuclear positivity for ki-67 in BC animals were 12.4% (IC 10.1-14.6%), 13.2% (IC 10.5-15.9%) and 8.8% (IC 6.0-11.6%) in BCG, NTZ and NTZ + BCG group, respectively (p = 0.063). Between animals with carcinoma, c-Myc strong positive was 40.10% in NTZ, 32.2% in BCG and 19.90% in the NTZ + BCG group (p < 0.001). Blotting has shown mTOR (p = 0.0473) and PI3K inhibition (p = 0.0349) in the presence of BCG, added to 4-EBP inhibition in the presence of NTZ (p = 0.0004). CONCLUSIONS: Results show the possible synergy between the gold standard BC treatment BCG and NTZ, in which multiple targets inhibition such as c-Myc and downstream mTOR, p-4E-BP and PI3K might play a role.

Conjugated linoleic acid and cardiac health: oxidative stress and energetic metabolism in standard and sucrose-rich diets.

Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n=6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO(2)/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions, and triacylglycerol accumulation in S-CLA rats. Conjugated linoleic acid depressed myocardial LDH comparing C-CLA with C, and beta-hydroxyacyl-coenzyme-A dehydrogenase/CS ratio, comparing S-CLA with S. In conclusion, dietary conjugated linoleic acid supplementation for weight loss can have long-term effects on cardiac health. Conjugated linoleic acid, isomers c9, t11 and t10, c12c9,t11" and "t10,c12" were changed to "c9, t11" and "t10, c12", respectively. Please check if appropriate.--> presented undesirable pro-oxidant effect and induced metabolic changes in cardiac tissue. Nevertheless, despite its effect on abdominal adiposity in sucrose-rich diet condition, conjugated linoleic acid may be disadvantageous because it can lead to oxidative stress and dyslipidemic profile.

Insulin Resistance in HIV-Patients: Causes and Consequences.

Here we review how immune activation and insulin resistance contribute to the metabolic alterations observed in HIV-infected patients, and how these alterations increase the risk of developing CVD. The introduction and evolution of antiretroviral drugs over the past 25 years has completely changed the clinical prognosis of HIV-infected patients. The deaths of these individuals are now related to atherosclerotic CVDs, rather than from the viral infection itself. However, HIV infection, cART, and intestinal microbiota are associated with immune activation and insulin resistance, which can lead to the development of a variety of diseases and disorders, especially with regards to CVDs. The increase in LPS and proinflammatory cytokines circulating levels and intracellular mechanisms activate serine kinases, resulting in insulin receptor substrate-1 (IRS-1) serine phosphorylation and consequently a down regulation in insulin signaling. While lifestyle modifications and pharmaceutical interventions can be employed to treat these altered metabolic functions, the mechanisms involved in the development of these chronic complications remain largely unresolved. The elucidation and understanding of these mechanisms will give rise to new classes of drugs that will further improve the quality of life of HIV-infected patients, over the age of 50.

Influence of AIN-93 diet on mortality and cardiac remodeling after myocardial infarction in rats.

BACKGROUND: The AIN-93 diet was proposed by the American Institute of Nutrition with the objective of standardising studies in experimental nutrition. Our objective was to analyze the effects of AIN-93 diet after myocardial infarction in rats. METHODS: Post weaning, the animals were divided into two groups: control (C, n=62), fed the standard diet of our laboratory (Labina); AIN-93 Group (n=70), fed the AIN-93 diet. Achieving 250 g, the animals were subjected to myocardial infarction. RESULTS: Early mortality was increased in AIN-93 animals, associated with lower serum levels of calcium, magnesium, potassium, sodium, and phosphorus. On the other hand, after 90 days, AIN-93 showed smaller normalized left ventricular dimensions. The caloric and carbohydrate intake was smaller, but the fat intake was higher in AIN-93 rats. AIN-93 group also showed increased levels of ß-hydroxyacylcoenzyme A dehydrogenase and citrate synthase. In addition, serum levels of insulin and cardiac levels of malondialdehyde, metalloproteinases-2 and -9, and TNF-α and IFN-γ were decreased in the AIN-93 group. CONCLUSION: AIN-93 diet increased early mortality, while attenuated the chronic remodeling process after experimental coronary occlusion. Therefore, this diet has biological effects and should be use with attention in this model.