Effect of Parenteral Supplementation of Minerals and Vitamins on Oxidative Stress Biomarkers and Hepatic Fatty Acid Metabolism in Dairy Cows During the Transition Period.

In the present work we aimed to study the effects of parenteral vitamin and mineral supplementation on hepatic fatty acid metabolism as well as on the oxidative stress biomarkers in biological samples of transition cows. The supplemented group (SG, n = 11) received a subcutaneous injection of 5 mL of vitamin A palmitate 35 mg/mL, vitamin E acetate 50 mg/mL plus other injection of 5 mL of copper edetate 10 mg/mL, zinc edetate 40 mg/mL, manganese edetate 10 mg/mL, and sodium selenite 5 mg/mL on days - 60, - 30, and 7 (± 3) relative to calving. The control group (CG, n = 11) received two subcutaneous injections of 5 mL of 9 mg/mL sodium chloride at the same times of the SG. Blood, urine, and liver biopsies were sampled 21 (± 3) days before the expected calving date and 7 and 21 (± 3) days after calving. Results revealed that supplemented animals had higher glutation peroxidase (GSH-Px) activity, lower and higher concentration of 3-nitrotyrosine (3-NT) in the liver and plasma, respectively, higher expression of the mitochondrial beta-oxidation enzyme carnitine palmitoyltransferase 1 in the liver, and lower content of hepatic triacylglycerol, mirroring plasma liver function parameters. No differences between groups were found in the superoxide dismutase activity, MDA concentrations, the protein abundance of peroxisomal acyl-CoA oxidase 1, diacylglycerol O-acyltransferase 1, and peroxisome proliferator-activated receptor alpha. These results suggest that the vitamin and mineral supplementation provided to dairy cows had a beneficial effect on GSH-Px activity, hepatic 3-NT concentration, and on the metabolic adaptation during the peripartum period.

Cytotoxic, antioxidant, and cytoprotective properties of polyphenol-enriched extracts from pecan nutshells in MDA-MB-231 breast cancer cells.

Phenolic compounds present in plants have demonstrated several biological properties such as antioxidant, antitumor, cardioprotective, and antiproliferative. On the other hand, doxorubicin, a chemotherapeutic widely used to treat breast cancer, usually exhibits chronic cardiotoxicity associated with oxidative stress. Therefore, we aimed to study the effects of phenolic compound-enriched extract (PCEE) with doxorubicin in breast cancer. To achieve this, after an SPE-C18 -column purification process of crude extracts obtained from pecan nutshells (Carya illinoinensis), the resulting PCEE was used to evaluate the cytotoxicity and antioxidant properties against the human breast cancer cell line MDA-MB-231 and the normal-hamster ovary cell line CHO-K1. PCEE was selectively cytotoxic against both cell lines, with an IC50 value (≈26.34 mg/L) for MDA-MB-231 lower than that obtained for CHO-K1 (≈55.63 mg/L). As a cytotoxic mechanism, PCEE inhibited cell growth by G2/M cell cycle arrest in MDA-MB-231 cells. Simultaneously, the study of the antioxidant activity showed that PCEE had a cytoprotective effect, evidenced by reduced ROS production in cells with oxidative stress caused by doxorubicin. The results highlight PCEE as a potential antitumor agent, thus revaluing it as an agro-industrial residue.

GLP-1 and GLP-2 as yin and yang of intestinal lipoprotein production: evidence for predominance of GLP-2-stimulated postprandial lipemia in normal and insulin-resistant states.

The glucagon-like peptides (GLP-1 and GLP-2) are processed from the proglucagon polypeptide and secreted in equimolar amounts but have opposite effects on chylomicron (CM) production, with GLP-1 significantly reducing and GLP-2 increasing postprandial chylomicronemia. In the current study, we evaluated the apparent paradoxical roles of GLP-1 and GLP-2 under physiological conditions in the Syrian golden hamster, a model with close similarity to humans in terms of lipoprotein metabolism. A short (30-min) intravenous infusion of GLP-2 resulted in a marked increase in postprandial apolipoprotein B48 (apoB48) and triglyceride (TG) levels in the TG-rich lipoprotein (TRL) fraction, whereas GLP-1 infusion decreased lipid absorption and levels of TRL-TG and apoB48. GLP-1 and GLP-2 coinfusion resulted in net increased lipid absorption and an increase in TRL-TG and apoB48. However, prolonged (120-min) coinfusion of GLP-1 and GLP-2 decreased postprandial lipemia. Blocking dipeptidyl peptidase-4 activity resulted in decreased postprandial lipemia. Interestingly, fructose-fed, insulin-resistant hamsters showed a more pronounced response, including possible hypersensitivity to GLP-2 or reduced sensitivity to GLP-1. In conclusion, under normal physiological conditions, the actions of GLP-2 predominate; however, when GLP-1 activity is sustained, the hypolipidemic action of GLP-1 predominates. Pharmacological inhibition of GLP-1 degradation tips the balance toward an inhibitory effect on intestinal production of atherogenic CM particles.

Nuclear receptors and hepatic lipidogenic enzyme response to a dyslipidemic sucrose-rich diet and its reversal by fish oil n-3 polyunsaturated fatty acids.

A sucrose-rich diet (SRD), compared with a starch diet, induces time-dependent metabolic disorders and insulin resistance with hypertriglyceridemia, similar to type 2 diabetes. In this study, we examined the effect of SRD, after 8 mo, on nuclear receptors peroxisome proliferator-activated receptor-alpha (PPARalpha), and liver X receptor-alpha (LXRalpha), stearoyl-CoA desaturase-1 (SCD-1), and Delta6 and Delta5 desaturases mRNA and activity, hepatic enzymes involved in lipid metabolism, and fatty acid (FA) composition as well as the reversal produced by cod liver oil. SRD induced triglyceride increase in plasma and liver, increasing the anabolic FA synthase, malic enzyme, and glucose-6-phosphate dehydrogenase, but not the prooxidative enzymes FA oxidase and carnitine palmitoyltransferase I, and correspondingly decreased PPARalpha and increased LXRalpha expressions. Results suggest a contribution of both nuclear receptors' interaction on these enzymatic activities. SRD depressed SCD-1 without altering oleic acid proportion and increased Delta6 and Delta5 desaturases and the proportion of n-6 arachidonic acid. Therefore, the data do not support that SRD hypertriglyceridemia is produced by increased SCD-1-dependent oleic acid biosynthesis. The administration of 7% cod liver oil for 2 mo depressed LXRalpha, enhancing PPARalpha in control and SRD-fed rats, reversing the activity of the hepatic enzymes involved in lipid metabolism and therefore the hyperlipidemia produced by the SRD. Fish oil increased n-3 PUFA and depressed n-6 PUFA of liver lipids without altering the 18:1/18:0 ratio, suggesting that its effects were produced mainly by competition of dietary n-6 and n-3 FA and not through desaturase activity modification.