High fructose diet-induced obesity worsens post-ischemic brain injury in the hippocampus of female rats.

Objectives: Cerebral ischemia is caused by a reduction of the blood flow in a specific area in the brain, triggering cellular cascades in the tissue that result in neuronal death. This phenomenon leads to neurological decline in patients with stroke. The extent of the injury after stroke could be related to the condition of obesity. Thus, we aim to analyze the effect of obesity induced by a high fructose diet (HFD) on the brain after cerebral ischemia in rats.Methods: We induced the obesity model in female Wistar rats with 20% fructose in water for 11 weeks. We then performed cerebral ischemia surgery (2-vessel occlusion), carried out the neurological test 6, 24 and 48 h post-ischemia and analyzed the histological markers.Results: The HFD induced an obese phenotype without insulin resistance. The obese rats exhibited worse neurological performance at 6 h post-ischemia and showed neuronal loss and astroglial and microglial immunoreactivity changes in the caudate putamen, motor cortex, amygdala and hippocampus at 48 h post-ischemia. However, the most commonly affected area was the hippocampus, where we found an increase in interleukin 1ß in the blood vessels of the dentate gyrus, a remarkable disruption of MAP-2+ dendrites, a loss of brain-derived neurotrophic factor and the presence of PHF-tau. In conclusion, a HFD induces an obese phenotype and worsens the neuronal loss, inflammation and plasticity impairment in the hippocampus after cerebral ischemia.

Ursolic Acid Lactone Obtained from Eucalyptus tereticornis Increases Glucose Uptake and Reduces Inflammatory Activity and Intracellular Neutral Fat: An In Vitro Study.

Obesity has a strong relationship to insulin resistance and diabetes mellitus, a chronic metabolic disease that alters many physiological functions. Naturally derived drugs have aroused great interest in treating obesity, and triterpenoids are natural compounds with multiple biological activities and antidiabetic mechanisms. Here, we evaluated the bioactivity of ursolic acid lactone (UAL), a lesser-known triterpenoid, obtained from Eucalyptus tereticornis. We used different cell lines to show for the first time that this molecule exhibits anti-inflammatory properties in a macrophage model, increases glucose uptake in insulin-resistant muscle cells, and reduces triglyceride content in hepatocytes and adipocytes. In 3T3-L1 adipocytes, UAL inhibited the expression of genes involved in adipogenesis and lipogenesis, enhanced the expression of genes involved in fat oxidation, and increased AMP-activated protein kinase phosphorylation. The range of biological activities demonstrated in vitro indicates that UAL is a promising molecule for fighting diabetes.

Metabolic Activity of Anthocyanin Extracts Loaded into Non-ionic Niosomes in Diet-Induced Obese Mice.

PURPOSE: Anthocyanins (ACNs) are polyphenols that might reduce pathological processes associated with type 2 diabetes mellitus and other chronic diseases, but their bioavailability is still controversial. In this study, the metabolic activity of oral delivery of ACN-loaded niosomes was investigated and evaluated in a diet-induced obesity (DIO) mice model. METHODS: ACNs extracted from Vaccinium Meridionale by the supercritical fluid extraction method were loaded in niosomes. The niosomal formulation was physically characterized and further administrated in drinking water to obese, insulin resistant mouse. We evaluated the effect of ACN loaded niosomes on hyperglycemia, glucose and insulin intolerance and insulin blood levels in C57BL/6 J mice fed with a high-fat diet. RESULTS: The ACN-loaded particles were moderately monodisperse, showed a negative surface charge and 57% encapsulation efficiency. The ACN-loaded niosomes ameliorated the insulin resistance and glucose intolerance in the DIO mice model. Additionally, they reduced animal weight and plasma insulin, glucose, leptin and total cholesterol levels in obese mice. CONCLUSION: ACN-loaded niosomes administration, as a functional drink, had a beneficial effect on the reversal of metabolic abnormalities associated with obesity.

Biguanide-transition metals complexes as potential drug for hyperglycemia treatment.

Coordination compounds of Cu(ii), Ni(ii), Co(ii), and Zn(ii) with a type of biguanide (known commercially as metformin) have been synthesized and characterized using spectroscopic techniques (FT-IR, UV/VIS), X-ray diffraction techniques and thermal analysis. For all compounds, single crystals were obtained for single-crystal X-ray diffraction. For the first time, an octahedral cobalt compound with the formula [Co(C4H11N5)3]Cl2·2H2O that crystallizes in the monoclinic space group C2/c with one molecule in the asymmetric unit has been obtained. Also, a novel nickel compound with the formula [Ni(C4H11N5) (C4H10N5)]Cl·H2O that crystallizes in the monoclinic space group P21/c with two molecules in the asymmetric unit was obtained. Finally, we obtained copper and zinc compounds that crystallize in the monoclinic space groups P21/n and P21/c with the general formula [Cu(C4H11N5)2]Cl2·H2O and [Zn(C4H12N5)Cl3], respectively. A structural and supramolecular analysis was developed for all compounds using Hirshfeld surface analysis and electrostatic potential maps. The cell viability of the obtained compounds was evaluated in C2C12 (ATCCCRL-1772™) mouse muscle cells and HepG2 (ATCC HB-8065™) human liver carcinoma cells by the MTT assay to determine the potential of the compounds as new safe drugs. The results demonstrate that the compounds exhibit low cytotoxicity at doses less than 250 µg mL-1 with a cell viability greater than 80%.

Immunometabolic regulation by triterpenes of Eucalyptus tereticornis in adipose tissue cell line models.

BACKGROUND: Eucalyptus tereticornis Sm (Myrtaceae) is a plant used in traditional medicine to control obesity, insulin resistance and diabetes. Chronic adipose tissue inflammation is involved in generating insulin resistance, the greatest risk factor in developing type 2 diabetes mellitus and cardiovascular disease. In the present study, a mixture of triterpenes, as obtained from the starting plant material, was evaluated in inflamed adipose tissue cells models. AIM: Our goal is to advance into the understanding, at the cellular level, of the immunometabolic effects of the triterpene mixes from Eucalyptus tereticornis in in vitro models of mouse and human adipose tissues. METHODS: Triterpene mixes were obtained from Eucalyptus tereticornis leaves by organic extraction. The major compounds of these mixes were identified by 1H NMR and 13C NMR in addition to HPLC using primary and secondary standards of ursolic acid, oleanolic acid and ursolic acid lactone. To provide an approach for evaluating the cellular and molecular mechanisms through which triterpene mixes act to modify the metabolic processes associated with obesity, mouse macrophage and adipocyte cell lines, human macrophage cell line and primary culture of human adipocytes were used as models. RESULTS: Adipocytes treated with the two natural chemically characterized triterpene mixes partially reduce lipogenesis and leptin expression. Additionally, an increase in the transcriptional expression of PPARγ, and C/EBPα is observed. In macrophages, these triterpene mixes, decrease the transcriptional and translational expression of pro-inflammatory cytokines, such as interleukin-6 (IL-6), interleukin 1ß (IL-1ß) and tumoral necrosis factor α (TNFα). Conditioned medium of 3T3-L1 adipocytes treated with the triterpene mix shows a stronger anti-inflammatory response on activated J774A.1 macrophages. CONCLUSION: The mixtures of the three triterpenes in the proportions obtained from the plant material may act on different components of the cell, generating a different response, which, in some cases, is more powerful than that seen when exposure to only two triterpenes. It makes this three triterpenes mix a good phytotherapeutic prototype for pathologies as complex as those associated with obesity.

Decreased IRS signaling impairs beta-cell cycle progression and survival in transgenic mice overexpressing S6K in beta-cells.

OBJECTIVE: The purpose of this study was to evaluate the role of the S6K arm of mammalian target of rapamycin complex 1 (mTORC1) signaling in regulation of ß-cell mass and function. Additionally, we aimed to delineate the importance of in vivo S6K activation in the regulation of insulin signaling and the extent to which alteration of insulin receptor substrate (IRS) signaling modulates ß-cell mass and function. RESEARCH DESIGN AND METHODS: The current experiments describe the phenotype of transgenic mice overexpressing a constitutively active form of S6K under the control of the rat insulin promoter. RESULTS: Activation of S6K signaling in these mice improved insulin secretion in the absence of changes in ß-cell mass. The lack of ß-cell mass expansion resulted from decreased G(1)-S progression and increased apoptosis. This phenotype was associated with increased p16 and p27 and decreased Cdk2 levels. The changes in cell cycle were accompanied by diminished survival signals because of impaired IRS/Akt signaling. CONCLUSIONS: This work defines the importance of S6K in regulation of ß-cell cycle, cell size, function, and survival. These experiments also demonstrate that in vivo downregulation of IRS signaling by TORC1/S6K induces ß-cell insulin resistance, and that this mechanism could explain some of the abnormalities that ultimately result in ß-cell failure and diabetes in conditions of nutrient overload.

Disruption of Tsc2 in pancreatic beta cells induces beta cell mass expansion and improved glucose tolerance in a TORC1-dependent manner.

Regulation of pancreatic beta cell mass and function is a major determinant for the development of diabetes. Growth factors and nutrients are important regulators of beta cell mass and function. The signaling pathways by which these growth signals modulate these processes have not been completely elucidated. Tsc2 is an attractive candidate to modulate these processes, because it is a converging point for growth factor and nutrient signals. In these experiments, we generated mice with conditional deletion of Tsc2 in beta cells (betaTsc2(-/-)). These mice exhibited decreased glucose levels and hyperinsulinemia in the fasting and fed state. Improved glucose tolerance in these mice was observed as early as 4 weeks of age and was still present in 52-week-old mice. Deletion of Tsc2 in beta cells induced expansion of beta cell mass by increased proliferation and cell size. Rapamycin treatment reversed the metabolic changes in betaTsc2(-/-) mice by induction of insulin resistance and reduction of beta cell mass. The reduction of beta cell mass in betaTsc2(-/-) mice by inhibition of the mTOR/Raptor (TORC1) complex with rapamycin treatment suggests that TORC1 mediates proliferative and growth signals induced by deletion of Tsc2 in beta cells. These studies uncover a critical role for the Tsc2/mTOR pathway in regulation of beta cell mass and carbohydrate metabolism in vivo.

[Differential display of messenger RNA and identification of selenocysteine lyase gene in hepatocellular carcinoma cells transiently expressing hepatitis C virus core protein]. / Presentación diferencial de ARN mensajeros e identificación del gen selenocisteína liasa en células de carcinoma hepatocelular con expresión transitoria de la proteína core del virus de la hepatitis C.

INTRODUCTION: Hepatitis C virus is associated with diverse liver diseases including acute and chronic hepatitis, steatosis, cirrhosis and hepatocellular carcinoma. Several studies have explored viral mechanisms involved in the establishment of persistent infection and oncogenic Hepatitis C virus. Expression assays of Hepatitis C virus core protein suggest that this protein has transforming and carcinogenic properties with multifunctional activities in host cells. Characterization of expressed genes in cells expressing Core protein is important in order to identify candidate genes responsible for these pathogenic alterations. OBJECTIVE: To compare and identify gene expression profiles in the human hepatocarcinoma derived cell line, HepG2, with transient expression of Hepatitis C virus Core protein. MATERIALS AND METHODS: We have used comparative PCR-mediated differential display of mRNA from HepG2 hepatocarcinoma with and without transient expression of HCV Core protein or green fluorescent protein, previously obtained using the Semliki Forest Virus-based expression, through transduction of recombinant particles, rSFV-Core and rSFV-GFP, respectively. RESULTS: We observed differences in band intensities of mRNA in HepG2 cells transduced with rSFV-Core compared with those detected in cells without transduction, and transduced with rSFV-GFP. Cloning and sequencing of a gene fragment (258 bp) that was expressed differentially in HepG2 cells transduced with rSFV-Core, was identified as selenocystein lyase. CONCLUSION: The results confirm that HCV Core protein expressed in HepG2 is associated with specific changes in mRNA expression, including the gene for selenocystein lyase. This gene may be involved in the pathophysiology of hepatocellular carcinoma.

Presentación diferencial de ARN mensajeros e identificación del gen selenocisteína liasa en células de carcinoma hepatocelular con expresión transitoria de la proteína core del virus de la hepatitis C / Differential display of messenger RNA and identification of selenocysteine luase gene in hepatocellular carcinoma cells transiently expressing hepatitis C virus Core protein

Introducción. El virus de la hepatitis C se asocia a diversas hepatopatías como hepatitis aguda, hepatitis crónica, esteatosis, cirrosis y carcinoma hepatocelular. Numerosos estudios han explorado mecanismos virales implicados en el establecimiento de la infección persistente y en las propiedades oncogénicas e inmunomoduladoras de la proteína core del virus de la hepatitis C. Las investigaciones orientadas a evaluar los cambios en la expresión de genes celulares endógenos inducidos por la proteína core son importantes para identificar genes candidatos responsables de los mecanismos de patogenicidad del virus de la hepatitis C. Objetivos. Comparar perfiles de expresión e identificar genes celulares endógenos en la línea celular derivada de carcinoma hepatocelular humano, HepG2, con expresión transitoria de la proteína core del virus de la hepatitis C. Materiales y métodos. Se utilizó la técnica de presentación diferencial de ARN mensajero por RT-PCR en células HepG2 con y sin expresión transitoria de la proteína core del virus de la hepatitis C o de la proteína verde fluorescente, obtenidas previamente con el sistema de expresión del Semliki Forest Virus, mediante transducción de partículas recombinantes rSFV-Core o rSFV-GFP. Resultados. Se observaron diferencias en las intensidades de las bandas de ARNm expresadas en células HepG2 transducidas con rSFV-Core comparadas con células sin transducir y trasducidas con rSFV-GFP. Un ARNm de 258 pb expresado diferencialmente en células HepG2 transducidas con rSFV-Core fue clonado e identificado como selenocisteína liasa. Conclusión. Los resultados confirman que la expresión de la proteína core del virus de la hepatitis C se asocia con cambios en la expresión de ARN mensajeros específicos, incluido al gen selenocisteina liasa, el cual puede estar involucrado en la fisiopatología del carcinoma hepatocelular

Akt induces beta-cell proliferation by regulating cyclin D1, cyclin D2, and p21 levels and cyclin-dependent kinase-4 activity.

Proliferation is the major component for maintenance of beta-cell mass in adult animals. Activation of phosphoinositide 3-kinase/Akt-kinase pathway is a critical regulator of beta-cell mass. Pancreatic beta-cell overexpression of constitutively active Akt in mice (caAkt(Tg)) resulted in marked expansion of beta-cell mass by increase in beta-cell proliferation and size. The current studies provide new insights into the molecular mechanisms involved in beta-cell proliferation by Akt. Proliferation of beta-cells in caAkt(Tg) was associated with increased cyclin D1, cyclin D2, and p21 levels and cyclin-dependent kinase-4 (cdk4) activity. To determine the role of cdk4 in beta-cell proliferation induced by Akt, we generated caAkt(Tg) mice that were homozygous, heterozygous, or nullizygous for cdk4. The results of these studies showed that deletion of one cdk4 allele significantly reduced beta-cell expansion in caAkt(Tg) mice by decreased proliferation. CaAkt(Tg) mice deficient in cdk4 developed beta-cell failure and diabetes. These experiments suggest that Akt induces beta-cell proliferation in a cdk4-dependent manner by regulation of cyclin D1, cyclin D2, and p21 levels. These data also indicate that alteration in levels of these cell cycle components could affect the maintenance of beta-cell mass in basal states and the adaptation of beta-cells to pathological states resulting in diabetes.

Emerging role of protein kinase B/Akt signaling in pancreatic beta-cell mass and function.

The serine-threonine kinase Akt also known as protein kinase B is one of the most studied molecules. In addition to the important role in carcinogenesis, Akt is a major regulator of carbohydrate metabolism. Akt mediates insulin-dependent glucose uptake in insulin-sensitive tissues. Recent evidence underscores the importance of Akt for regulation of beta-cell mass and function. This review summarizes current findings concerning the molecular mechanisms, downstream signaling pathways, and critical components involved in regulation of beta-cell mass and function by Akt. The results of these observations suggest that elucidation of critical downstream effectors of this signaling pathway could generate promising molecules as a potential target to induce proliferation and survival of beta-cells.

Sequence and phylogenetic analysis of human T cell lymphotropic virus type 1 from Tumaco, Colombia.

Human T cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes leukemia and the neurological disorder HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP). Infection with this virus - although it is distributed worldwide - is limited to certain endemic areas of the world. Despite its specific distribution and slow mutation rate, molecular epidemiology on this virus has been useful to follow the movements of human populations and routes of virus spread to different continents. In the present study, we analyzed the genetic variability of a region of the env gene of isolates obtained from individuals of African origin that live on the Pacific coast of Colombia. Sequencing and comparison of the fragment with the same fragment from different HTLV-1 isolates showed a variability ranging from 0.8% to 1.2%. Phylogenetic studies permit us to include these isolates in the transcontinental subgroup A in which samples isolated from Brazil and Chile are also found. Further analyses will be necessary to determine if these isolates were recently introduced into the American continent or if they rather correspond to isolates introduced during the Paleolithic period.

Sequence and phylogenetic analysis of human T cell lymphotropic virus type 1 from Tumaco, Colombia

Human T cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes leukemia and the neurological disorder HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP). Infection with this virus - although it is distributed worldwide - is limited to certain endemic areas of the world. Despite its specific distribution and slow mutation rate, molecular epidemiology on this virus has been useful to follow the movements of human populations and routes of virus spread to different continents. In the present study, we analyzed the genetic variability of a region of the env gene of isolates obtained from individuals of African origin that live on the Pacific coast of Colombia. Sequencing and comparison of the fragment with the same fragment from different HTLV-1 isolates showed a variability ranging from 0.8 percent to 1.2 percent. Phylogenetic studies permit us to include these isolates in the transcontinental subgroup A in which samples isolated from Brazil and Chile are also found. Further analyses will be necessary to determine if these isolates were recently introduced into the American continent or if they rather correspond to isolates introduced during the Paleolithic period