María Jesús Rodríguez-Yoldi

Intestinal d -Galactose Transport in an Endotoxemia Model in the Rabbit

Lipopolysaccharide (LPS) is an endotoxin causing sepsis. Studies from our laboratory revealed impaired intestinal absorption of l-leucine and d-fructose in LPS-treated rabbits. The aim of this study was to examine intestinal d-galactose transport following intravenous administration of LPS in the rabbit and to identify the cellular mechanisms driving this process. Endotoxin treatment diminished the buildup of d-galactose in intestinal tissue, the mucosal to serosal transepithelial flux of the sugar and its uptake by brush border membrane vesicles (BBMVs). Intracellular signaling pathways associated with protein kinase C (PKC), protein kinase A (PKA), p38 mitogen-activated protein kinase (p38MAPK), Jun N-terminal kinase (JNK), MAPK/extracellular signal-regulated kinases 1 and 2 (MEK1/2) and proteasome were found to be involved in this reduction in sugar uptake. Na+/glucose cotransporter 1 (SGLT1) protein levels in BBMVs were lower for LPS-treated animals than control animals. These findings indicate that LPS inhibits the intestinal absorption of d-galactose via a complex cellular mechanism that could involve posttranscriptional regulation of the SGLT1 transporter.

Inhibitory effect of TNF-α on the intestinal absorption of galactose

Sepsis is a systemic response to infection in which toxins, such as bacterial lipopolysaccharide (LPS), stimulate the production of inflammatory mediators like the cytokine tumor necrosis factor alpha (TNF‐α). Previous studies from our laboratory have revealed that LPS inhibits the intestinal absorption of L‐leucine and D‐fructose in rabbit when it was intravenously administered, and that TNF‐α seems to mediate this effect on amino acid absorption. To extend this work, the present study was designed to evaluate the possible effect of TNF‐α on D‐galactose intestinal absorption, identify the intracellular mechanisms involved and establish whether this cytokine mediates possible LPS effects. Our findings indicate that TNF‐α decreases D‐galactose absorption both in rabbit intestinal tissue preparations and brush‐border membrane vesicles. Western blot analysis revealed reduced amounts of the Na+/glucose cotransporter (SGLT1) protein in the plasma membrane attributable to the cytokine. On the contrary, TNF‐α increased SGLT1 mRNA levels. Specific inhibitors of the secondary messengers PKC, PKA, the MAP kinases p38 MAP, JNK, MEK1/2 as well as the proteasome, diminished the TNF‐α‐evoked inhibitory effect. LPS inhibition of the uptake of the sugar was blocked by a TNF‐α antagonist. In conclusion, TNF‐α inhibits D‐galactose intestinal absorption by decreasing the number of SGLT1 molecules at the enterocyte plasma membrane through a mechanism in which several protein‐like kinases are involved. J. Cell. Biochem. 101: 99–111, 2007.

Rosa canina extracts have antiproliferative and antioxidant effects on caco-2 human colon cancer

The in vitro antiproliferative and antioxidant effects of different fractions of Rosa canina hips on human colon cancer cell lines (Caco-2) was studied. The compounds tested were total extract (fraction 1), vitamin C (fraction 2), neutral polyphenols (fraction 3) and acidic polyphenols (fraction 4). All the extracts showed high cytotoxicity after 72 h, both low and high concentrations. The flow cytometric analysis revealed that all the fractions produce disturbances in the cell cycle resulting in a concomitant cell death by an apoptotic pathway. Changes in the redox status of Caco-2 cells in response to Rosa canina hips were determined. Cells were exposed to hydrogen peroxide in presence of plant fractions and the production of Reactive Oxygen Species (ROS) was significantly decreased. Therefore, our data demonstrate that rosehip extracts are a powerful antioxidant that produces an antiproliferative effect in Caco-2 cells. Therefore, these results predict a promising future for Rosa canina as a therapeutic agent. Thus, this natural plant could be an effective component of functional foods addressed towards colorectal carcinoma.

Dietary oleanolic acid mediates circadian clock gene expression in liver independently of diet and animal model but requires apolipoprotein A1

Oleanolic acid is a triterpene widely distributed throughout the plant kingdom and present in virgin olive oil at a concentration of 57 mg/kg. To test the hypotheses that its long-term administration could modify hepatic gene expression in several animal models and that this could be influenced by the presence of APOA1-containing high-density lipoproteins (HDLs), diets including 0.01% oleanolic acid were provided to Apoe- and Apoa1-deficient mice and F344 rats. Hepatic transcriptome was analyzed in Apoe-deficient mice fed long-term semipurified Western diets differing in the oleanolic acid content. Gene expression changes, confirmed by reverse transcriptase quantitative polymerase chain reaction, were sought for their implication in hepatic steatosis. To establish the effect of oleanolic acid independently of diet and animal model, male rats were fed chow diet with or without oleanolic acid, and to test the influence of HDL, Apoa1-deficient mice consuming the latter diet were used. In Apoe-deficient mice, oleanolic acid intake increased hepatic area occupied by lipid droplets with no change in oxidative stress. Bmal1 and the other core component of the circadian clock, Clock, together with Elovl3, Tubb2a and Cldn1 expressions, were significantly increased, while Amy2a5, Usp2, Per3 and Thrsp were significantly decreased in mice receiving the compound. Bmal1 and Cldn1 expressions were positively associated with lipid droplets. Increased Clock and Bmal1 expressions were also observed in rats, but not in Apoa1-deficient mice. The core liver clock components Clock-Bmal1 are a target of oleanolic acid in two animal models independently of the diets provided, and this compound requires APOA1-HDL for its hepatic action.

Therapeutic applications of rose hips from different rosa species

Rosa species, rose hips, are widespread wild plants that have been traditionally used as medicinal compounds for the treatment of a wide variety of diseases. The therapeutic potential of these plants is based on its antioxidant effects caused by or associated with its phytochemical composition, which includes ascorbic acid, phenolic compounds and healthy fatty acids among others. Over the last few years, medicinal interest in rose hips has increased as a consequence of recent research that has studied its potential application as a treatment for several diseases including skin disorders, hepatotoxicity, renal disturbances, diarrhoea, inflammatory disorders, arthritis, diabetes, hyperlipidaemia, obesity and cancer. In this review, the role of different species of Rosa in the prevention of treatment of various disorders related to oxidative stress, is examined, focusing on new therapeutic approaches from a molecular point of view.

Inhibitory effect of IL-1β on galactose intestinal absorption in rabbits.

Background/Aims: Recent studies from our laboratory have shown that nitric oxide is involved in the IL-1β-induced inhibition of D-fructose intestinal transport in rabbits. The aim of this work was to further the studies of IL-1β effect on D-galactose absorption in a septic state induced by intravenous administration of this cytokine. Methods: Galactose intestinal absorption was assessed employing three techniques: sugar uptake in jejunum everted rings, transepithelial flux in Ussing-type chambers and uptake assays in brush border membrane vesicles. The level of the Na+/D-glucose cotransporter (SGLT1) expression was analyzed by Western blot. Results: In sepsis condition the body temperature was increased and studies on cellular intestinal integrity have not shown modifications in the brush border membrane. However, D-galactose absorption across mucosa of jejunum was diminished in IL-1β treated rabbits. The levels of SGLT-1 were no significantly different in both animal groups (control and IL-1β treated), indicating that the cytokine could induce a reduction in the SGLT-1 functionality. The inhibition was significantly reversed by the activation of several PKC, PKA, MAPKs and nuclear factor (NF)-ĸB inhibitors administered 15 min before the IL-1β. Conclusion: The inhibitory effect of IL-1β on D-galactose absorption across mucosal side of enterocyte could be mediated by the activation of several kinases and nuclear factor (NF)-ĸB.

Chemical composition of rosehips from different Rosa species: an alternative source of antioxidants for the food industry

ABSTRACT It is important to explore new sources of natural additives because the demand for these compounds by consumers is increasing. These products also provide health benefits and help in food preservation. An unexplored source of nutrients and antioxidant compounds is rosehip, the fleshy fruit of roses. This work compares the antioxidant compound (vitamin C, neutral phenols and acidic phenols) content of four Rosa species rosehips: R. pouzinii, R. corymbifera, R. glauca and R. canina from different geographical zones. Results show quantitative variability in ascorbic acids and neutral phenols content, and quantitative and qualitative differences in acidic phenol content, depending on species. Vitamin C concentration was highly variable depending on species, R. canina being the one with the highest concentration and R. pouzinii the one with the lowest content. Variability was found in total neutral polyphenols concentration and a correlation between freshness of the rosehips and concentration of neutral polyphenols was also found. Significant differences were found in the acidic phenols content among the studied species. Generally antioxidant activity was higher in the vitamin C fraction.

Differential antioxidative and hypocholesterolemic responses to two fish protein hydrolysates (Sardina pilchardus and Boops boops) in cholesterol-fed rats

Purpose – The purpose of this study was to evaluate the antioxidant and hypocholesterolemic activities of sardine and bogue protein hydrolysates in cholesterol-fed rats. Design/methodology/approach – In total, 18 male Wistar rats (220 ± 10 g) fed 20 per cent casein, 1 per cent cholesterol and 0.5 per cent cholic acid were divided into three groups and received a daily gavage of 250 mg of sardine (SPH) or bogue (BPH) protein hydrolysates for 30 days. The third group, named control group (CG), received in the same conditions water. Lipoproteins were fractionated by size-exclusion fast protein liquid chromatography, and serum lipids, apolipoproteins and lipoproteins were assayed. Findings – In SPH and BPH groups, serum total cholesterol concentrations were −66 per cent lower than in CG. This corresponded to the decreased very low-density lipoprotein-C in the former groups. Moreover, BPH treatment reduced low-density lipoprotein-C compared with CG and SPH groups. Compared with CG, serum phospholipids were red...

Involvement of Intracellular Signaling in the IL‐1β Inhibitory Effect on Fructose Intestinal Absorption

A variety of bacteria and their excreted/secreted products having direct effects on epithelial ion transport and permeability and the release of cytokines during bacterial infection may impact directly on epithelial function. Interleukin‐1β (IL‐1β) is a pleiotropic cytokine that affects the intestinal absorption of nutrients. The aim of this work was to study the intracellular signaling pathways involved in the inhibitory effect of IL‐1β on D‐fructose intestinal transport in rabbit jejunum and Caco‐2 cells. The results show that the cytokine inhibitory effect was completely reversed in presence of proteasome or PKC selective inhibitors in IL‐1β treated rabbits. In addition, the activation of PI3K abolished the IL‐1β effect. Likewise, these results were confirmed in Caco‐2 cells. In addition, p‐PI3K expression was increased by IL‐1β‐treatment whereas the expression of p‐PKCα was not significantly affected. In summary, the results suggest that IL‐1β could regulate the activation of pPKCα 73, pPI3K 55, and NF‐kB proteins. These events could exert an inhibitory effect on fructose intestinal absorption by a modification of GLUT5 insertion to brush‐border membrane and/or the functional transporter activity. This effect is independent of hormonal milieu and nervous stimuli. J. Cell. Physiol. 230: 896–902, 2015.

Hypocholesterolaemic and antioxidant efficiency of chickpea (Cicer arietinum) protein hydrolysates depend on its degree of hydrolysis in cholesterol-fed rat

Purpose The purpose of this study was to determine the effects of chickpea (Cicer arietinum) protein hydrolysates prepared at two degrees of hydrolysis (DH) on lipoprotein profile and on oxidant status in cholesterol-fed rats. Design/methodology/approach Eighteen male Wistar rats (220 ± 10 g) were divided into three groups and fed for 30 days a diet containing 20 per cent casein supplemented with 1 per cent cholesterol and 0.5 per cent cholic acid. During the experimentation, the first and the second groups received daily by gavage 250 mg of chickpea protein hydrolysates/rat at DH = 8 per cent (CPH8) and DH = 17 per cent (CPH17), respectively. The third group, named control group (CG), received water under the same conditions. Findings Serum total cholesterol concentrations were reduced in CPH8 (p < 0.0073) and CPH17 (p < 0.0004) groups versus CG. This reduction corresponded to a lower very-low-density lipoprotein (VLDL)-cholesterol (p < 0,0019). CPH17 reduced low-density lipoprotein- and high-density lipoprotein (HDL)-cholesterol (p < 0.0001) but increased apolipoprotein A4 (p < 0.002) concentrations and lecithin-cholesterol acyltransferase activity (p < 0.0001). APOA1 remained unchanged in the treated groups. Liver total and esterified cholesterol contents were twofold lower in both treated groups versus CG. CPH8 increased triacylglycerols and phospholipids (p < 0.0001) contents, while CPH17 decreased those of unesterified cholesterol (p < 0.0016). Compared with CG, CPH8 and CPH17 reduced serum (p < 0.0001) and lipoprotein hydroperoxides by stimulating paraoxonase activity (p < 0.0001). However, only CPH17 treatment reduced serum, VLDL- and HDL-malondialdehyde contents and improved glutathione peroxidase activity (p < 0.061). Originality/value Thus, chickpea protein hydrolysates and especially hydrolysed at DH = 17 per cent may have a great potential for use as a nutraceutical to reduce hypercholesterolaemia and, by consequence, oxidative stress. Therefore, the degree of enzymatic hydrolysis has a significant influence on the production of potent bioactive peptides.