Creatine supplementation reduces oxidative stress biomarkers after acute exercise in rats

The objective of this study was to evaluate the effect of creatine supplementation on muscle and plasma markers of oxidative stress after acute aerobic exercise. A total of 64 Wistar rats were divided into two groups: control group (n = 32) and creatine-supplemented group (n = 32). Creatine supplementation consisted of the addition of 2% creatine monohydrate to the diet. After 28 days, the rats performed an acute moderate aerobic exercise bout (1-h swimming with 4% of total body weight load). The animals were killed before (pre) and at 0, 2 and 6 h (n = 8) after acute exercise. As expected, plasma and total muscle creatine concentrations were significantly higher (P < 0.05) in the creatine-supplemented group compared to control. Acute exercise increased plasma thiobarbituric acid reactive species (TBARS) and total lipid hydroperoxide. The same was observed in the soleus and gastrocnemius muscles. Creatine supplementation decreased these markers in plasma (TBARS: pre 6%, 0 h 25%, 2 h 27% and 6 h 20%; plasma total lipid hydroperoxide: pre 38%, 0 h 24%, 2 h 12% and 6 h 20%, % decrease). Also, acute exercise decreased the GSH/GSSG ratio in soleus muscle, which was prevented by creatine supplementation (soleus: pre 8%, 0 h 29%, 2 h 30% and 6 h 44%, % prevention). The results show that creatine supplementation inhibits increased oxidative stress markers in plasma and muscle induced by acute exercise.

Antioxidant defenses and biochemical changes in the neotropical fish pacu, Piaractus mesopotamicus: Responses to single and combined copper and hypercarbia exposure

This study investigated the potentially detrimental effects of copper and elevated aquatic CO2 (hypercarbia), alone or in combination, on pacu, Piaractus mesopotamicus. Fish were exposed for 48 h to control (no copper addition in normocarbia), to 400 mu g Cu2+L-1, to hypercarbic (1% CO2; PCO2=6.9 mm Hg) water and to 400 mu g Cu2+L-1+ hypercarbia. In liver the single factors caused an increase in lipid hydroperoxide concentration that was not observed when the factors were combined. Copper exposure elicited increased hepatic superoxide dismutase activity, irrespective of aquatic CO2 level. On the other hand, the effects of copper on hepatic glutathione peroxidase activity were dependent on water CO2 levels. The two stressors combined did not affect hepatic catalase activity. Hypercarbic water caused a decline in plasma glucose concentration, but this was not observed when hypercarbia was combined with copper exposure. Copper caused a decrease in branchial Na+/K+-ATPase activity that was independent of water CO2 level. Copper caused an increase in branchial metallothionein concentration that was independent of water CO2 level. Thus, branchial metallothionein and Na+/K+-ATPase were effective biomarkers of copper exposure that were not affected by water CO2 level. (C) 2012 Elsevier Inc. All rights reserved.

Lipid biomarkers in surface sediments from an unusual coastal upwelling area from the SW Atlantic Ocean

The coastal upwelling off Cabo Frio (SE Brazilian coast, SEBC) represents an exception to the world`s oceans since the majority of the upwelling areas are located in eastern boundary current systems. Cabo Frio represents an interesting area for investigation due to its tight physical-biological interaction and the importance of the region as a major fishery area in the SEBC. We analyzed a suite of lipid biomarkers to apportion the main sources of organic matter in surface sediments of the continental shelf off Cabo Frio, comparing the area to non-upwelling regions off the SEBC (shelf break off Cabo Frio and continental shelf off Ubatuba). During spring and summer (the upwelling period), diatoms are probably the major sources of polyunsaturated fatty acids (PUFAs) and C-28 sterols in surface sediments from Cabo Frio continental shelf. Sediments sampled in winter showed, in contrast, lower relative abundance of PUFAs and higher stanol/stenol ratio values. In deeper regions off Cabo Frio, elevated concentrations of alkenones, 24-methylcholest-5,22E-dien-3 beta-ol and 24-ethylcholest-5-en-3 beta-ol during the spring may be produced by prymnesiophytes or cryptophytes and cyanobacteria, respectively. In Ubatuba, the C-27 and C-28 sterols are likely derived from omnivorous salps and nanoflagellates. At non-upwelling areas, despite the increase in biomarker concentrations during spring and summer, lower concentrations of PUFAs, phytol and algal sterols than in shelf areas off Cabo Frio suggest the importance of the upwelling system to the rapid transfer of organic carbon to surface sediments. Our results suggest that spatial and temporal variability in organic matter production and deposition merits consideration for constraining the carbon budgets in the coastal region off Cabo Frio. (C) 2008 Elsevier Ltd. All rights reserved.

Biomarkers of exposure to metal contamination and lipid peroxidation in the benthic fish Cathorops spixii from two estuaries in South America, Brazil

Biomarkers as lipid peroxidation, metallothionein and delta-aminolevulinic acid dehydratase were determined in Cathorops spixii to compare the biological responses of this fish from estuaries with distinct anthropogenic influence. Three areas were selected in two estuaries in accordance with the levels of contamination for the polluted (Santos/So Vicente) and with the hydrodynamic characteristics for the non-polluted (Canan,ia) estuary. Water characteristics and mercury levels in C. spixii confirmed a high human influence in the polluted system. In general, the biomarkers showed differences between the estuaries, suggesting disturbances in the specific cell mechanisms due to the presence of multiple xenobiotics in the contaminated system. Therefore, these biomarkers are recommended to promote more accurate information about the exposure to pollutants. Additionally, the study of the effect of the multiple xenobiotics on resident species such as the benthic fish C. spixii can favor a better assessment of the environmental quality of these systems.

Hemocompatibility of poly(epsilon-caprolactone) lipid-core nanocapsules stabilized with polysorbate 80-lecithin and uncoated or coated with chitosan

The hemocompatibility of nanoparticles is of critical importance for their systemic administration as drug delivery systems. Formulations of lipid-core nanocapsules, stabilized with polysorbate 80-lecithin and uncoated or coated with chitosan (LNC and LNC-CS), were prepared and characterized by laser diffraction (D[4,3]: 129 and 134 nm), dynamic light scattering (119 nm and 133 nm), nanoparticle tracking (D50: 124 and 139 nm) and particle mobility (zeta potential: -15.1 mV and + 9.3 mV) analysis. In vitro hemocompatibility studies were carried out with mixtures of nanocapsule suspensions in human blood at 2% and 10% (v/v). The prothrombin time showed no significant change independently of the nanocapsule surface potential or its concentration in plasma. Regarding the activated partial thromboplastin time, both suspensions at 2% (v/v) in plasma did not influence the clotting time. Even though suspensions at 10% (v/v) in plasma decreased the clotting times (p < 0.05), the values were within the normal range. The ability of plasma to activate the coagulation system was maintained after the addition of the formulations. Suspensions at 2% (v/v) in blood showed no significant hemolysis or platelet aggregation. In conclusion, the lipid-core nanocapsules uncoated or coated with chitosan are hemocompatible representing a potential innovative nanotechnological formulation for intravenous administration. (C) 2012 Elsevier B. V. All rights reserved.

Temperature-Dependence of Cationic Lipid Bilayer Intermixing: Possible Role of Interdigitation

In this work, we investigated the properties of a fusogenic cationic lipid, diC14-amidine, and show that this lipid possesses per se the capacity to adopt either an interdigitated structure (below and around its transition temperature) or a lamellar structure (above the transition temperature). To provide experimental evidence of this lipid bilayer organization, phospholipids spin-labeled at different positions of the hydrocarbon chain were incorporated into the membrane and their electron spin resonance (ESR) spectra were recorded at different temperatures. For comparison, similar experiments were performed with dimyristoyl phosphatidylcholine, a zwitterionic lipid (DMPC) which adopts a bilayer organization over a broad temperature range. Lipid mixing between diC14-amidine and asolectin liposomes was more efficient below (10-15 degrees C) than above the transition temperature (above 25 degrees C). This temperature-dependent "fusogenic" activity of diC14-amidine liposomes is opposite to what has been observed so far for peptides or virus-induced fusion. Altogether, our data suggest that interdigitatiori is a highly fusogenic state and that interdigitation-mediated fusion occurs via an unusual temperature-dependent mechanism that remains to be deciphered.

Lipid levels in the second year of life among HIV-infected and HIV-exposed uninfected Latin American children

Background: Dyslipidemia is observed among older children and adults with HIV. We examined nonfasting cholesterol and triglycerides in two groups of 12-23-month-old Latin American children - HIV-infected vs. HIV-exposed but uninfected (HEU). Methods: HIV-infected and HEU children in Latin America and Jamaica were enrolled in an observational cohort. Eligibility for this analysis required having cholesterol and triglyceride results available during the second year of life. Results: HIV-infected (n = 83) children were slightly older at the time of lipid testing than the HEU (n 681). Forty percent of the HIV-infected children were on protease inhibitor-based antiretroviral therapy (ART); 41% were not on ART. There was no statistically significant difference in mean cholesterol concentrations (mg/dl) by HIV status; however, the HIV-infected children had higher mean triglyceride concentrations. The prevalence of high cholesterol (>200 mg/dl) and high triglycerides (>110 mg/dl) was higher among the HIV-infected vs. HEU. Among the HIV-infected children, mean cholesterol and triglyceride concentrations varied by ART. Children receiving no ART had a significantly lower mean cholesterol concentration. Those receiving protease inhibitor-containing ART had a significantly higher mean triglyceride concentration compared to the other two antiretroviral regimen groups. Conclusion: A greater proportion of HIV-infected children at 12-23 months have hyperlipidemia when compared to HEU children, with the highest triglyceride concentrations observed among those receiving protease inhibitor-containing ART, and the lowest cholesterol levels among those not receiving ART. Implications of these findings will require continued follow-up of HIV-infected children who initiate therapy early in life. (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

Linker for Activation of T-cell Family Member2 (LAT2) a Lipid Raft Adaptor Protein for AKT Signaling, Is an Early Mediator of Alkylphospholipid Anti-leukemic Activity

Lipid rafts are highly ordered membrane domains rich in cholesterol and sphingolipids that provide a scaffold for signal transduction proteins; altered raft structure has also been implicated in cancer progression. We have shown that 25 mu M 10-(octyloxy) decyl-2-(trimethylammonium) ethyl phosphate (ODPC), an alkylphospholipid, targets high cholesterol domains in model membranes and induces apoptosis in leukemia cells but spares normal hematopoietic and epithelial cells under the same conditions. We performed a quantitative (SILAC) proteomic screening of ODPC targets in a lipid-raft-enriched fraction of leukemic cells to identify early events prior to the initiation of apoptosis. Six proteins, three with demonstrated palmitoylation sites, were reduced in abundance. One, the linker for activation of T-cell family member 2 (LAT2), is an adaptor protein associated with lipid rafts in its palmitoylated form and is specifically expressed in B lymphocytes and myeloid cells. Interestingly, LAT2 is not expressed in K562, a cell line more resistant to ODPC-induced apoptosis. There was an early loss of LAT2 in the lipid-raft-enriched fraction of NB4 cells within 3 h following treatment with 25 mu M ODPC. Subsequent degradation of LAT2 by proteasomes was observed. Twenty-five mu M ODPC inhibited AKT activation via myeloid growth factors, and LAT2 knockdown in NB4 cells by shRNA reproduced this effect. LAT2 knockdown in NB4 cells also decreased cell proliferation and increased cell sensitivity to ODPC (7.5X), perifosine (3X), and arsenic trioxide (8.5X). Taken together, these data indicate that LAT2 is an early mediator of the anti-leukemic activity of alkylphospholipids and arsenic trioxide. Thus, LAT2 may be used as a target for the design of drugs for cancer therapy. Molecular & Cellular Proteomics 11: 10.1074/mcp.M112.019661, 1898-1912, 2012.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Lipid and selenium sources on fatty acid composition of intramuscular fat and muscle selenium concentration of Nellore steers

The objective of this study was to evaluate the effect of lipid and selenium sources in diets for finishing Nellore steers on the fatty acid composition and selenium concentration of the longissimus muscle. Fifty Nellore steers (body weight = 458 +/- 39 kg) were assigned to one of six dietary treatments: 1) diet containing sunflower seed and inorganic selenium; 2) sunflower seed and organic selenium; 3) whole cottonseed and inorganic selenium; 4) whole cottonseed and organic selenium; 5) soybeans and inorganic selenium; and 6) soybeans and organic selenium. Diets were formulated with the same amount of nitrogen and calories and supplied once daily to steers in collective pens, with three animals per pen, for 120 d. At the end of the trial, steers were slaughtered and samples of the longissimus muscle were collected for fatty acid and selenium analysis. Effect of selenium sources was detected for selenium concentration in the longissimus muscle. Organic selenium had higher concentrations in the meat compared with inorganic selenium. The total saturated, monounsaturated and polyunsaturated fatty acids did not differ between the sources of lipids and selenium. For selenium sources, no differences were observed between the concentrations of polyunsaturated fat. Also, no differences in C18:2 cis-9 trans-11 concentrations were noted; however, steers fed sunflower seed presented greater proportions of this fatty acid in the meat. The results indicated that the use of sunflower seed, cottonseed or soybeans and organic or inorganic selenium in feedlot diets to Nellore cattle does not alter the great part of the fatty acid profile of the longissimus muscle. However, the inclusion of sunflower seed in the diet increases the meat CLA cis-9, trans-11, which is desirable and beneficial for the health of consumers.

Carbohydrate supplementation increases intramyocellular lipid stores in elite runners

The objective was to determine the effects of carbohydrate (CHO) supplementation on exercise-induced hormone responses and post-training intramyocellular lipid stores (IMCL). Twenty-four elite male athletes (28.0 +/- 1.2 years) were randomized to receive CHO (maltodextrin solution) or zero energy placebo solution (control group). The high-intensity running protocol consisted of 10 x 800 m at 100% of the best 3000-m speed (Vm3 km) and 2 x 1000 m maximal bouts in the morning and a submaximal 10-km continuous easy running in the afternoon of day 9. IMCL concentrations were assessed by H-1-MRS before (-day 9) and after training (day 9) in soleus (SO) and tibialis anterior (TA) muscles. Blood hormones were also measured before, during, and post-exercise. The percent change (Delta%) in TA-IMCL was higher in the CHO group (47.9 +/- 24.5 IMCL/Cr) than in the control group (-1.7 +/- 13.1, respectively) (P=.04). Insulin concentrations were higher in the CHO group post-intermittent running compared to control (P=.02). Circulating levels of free fatty acids and GH were lower in the CHO group (P>.01). The decline in performance in the 2nd 1000-m bout was also attenuated in this group compared to control (P<.001 and P=.0035, respectively). The hormonal milieu (higher insulin and lower GH levels) in the CHO group, together with unchanged free fatty acid levels, probably contributed to the increased IMCL stores. This greater energy storage capacity may have improved post-exercise recovery and thus prevented performance deterioration. (C) 2012 Elsevier Inc. All rights reserved.

Carbohydrate- and lipid-enriched meals acutely disrupt glycemic homeostasis by inducing transient insulin resistance in rats

Chronic intake of high-carbohydrate or high-lipid diets is a well-known insulin resistance inducer. This study investigates the immediate effect (1-6 h) of a carbohydrate-or lipid-enriched meal on insulin sensitivity. Fasted rats were refed with standard, carbohydrate-enriched (C), or lipid-enriched (L) meal. Plasma insulin, glucose, and non-esterified fatty acids (NEFA) were measured at 1, 2, 4, and 6 h of refeeding. The glucose-insulin index showed that either carbohydrates or lipids decreased insulin sensitivity at 2 h of refeeding. At this time point, insulin tolerance tests (ITTs) and glucose tolerance tests (GTTs) detected insulin resistance in C rats, while GTT confirmed it in L rats. Reduced glycogen and phosphorylated AKT and GSK3 content revealed hepatic insulin resistance in C rats. Reduced glucose uptake in skeletal muscle subjected to the fatty acid concentration that mimics the high NEFA level of L rats suggests insulin resistance in these animals is mainly in muscle. In conclusion, carbohydrate-or lipid-enriched meals acutely disrupt glycemic homeostasis, inducing a transient insulin resistance, which seems to involve liver and skeletal muscle, respectively. Thus, the insulin resistance observed when those types of diets are chronically consumed may be an evolution of repeated episodes of this transient insulin resistance.

Effects of extrusion, lipid concentration and purity on physico-chemical and biological properties of cationic liposomes for gene vaccine applications

We developed cationic liposomes containing DNA through a conventional process involving steps of (i) preformation of liposomes, (ii) extrusion, (iii) drying and rehydration and (iv) DNA complexation. Owing to its high prophylactic potentiality against tuberculosis, which had already been demonstrated in preclinical assays, we introduced modifications into the conventional process towards getting a simpler and more economical process for further scale-up. Elimination of the extrusion step, increasing the lipid concentration (from 16 to 64 mM) of the preformed liposomes and using good manufacturing practice bulk lipids (96-98% purity) instead of analytical grade purity lipids (99.9-100%) were the modifications studied. The differences in the physico-chemical properties, such as average diameter, zeta potential, melting point and morphology of the liposomes prepared through the modified process, were not as significant for the biological properties, such as DNA loading on the cationic liposomes, and effective immune response in mice after immunisation as the control liposomes prepared through the conventional process. Beneficially, the modified process increased productivity by 22% and reduced the cost of raw material by 75%.

Hydroxychloroquine reduces low-density lipoprotein cholesterol levels in systemic lupus erythematosus: a longitudinal evaluation of the lipid-lowering effect

The influence of antimalarials on lipids in systemic lupus erythematosus (SLE) has been identified in several studies but not in many prospective cohorts. The aim of this study was to longitudinally determine the effect of antimalarials on the lipoprotein profile in SLE. Patients and methods: Fasting total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL) and low-density lipoprotein cholesterol (LDL) plasma levels were determined at entry and after 3 months of hydroxychloroquine (HCQ) treatment in a longitudinal evaluation of 24 patients with SLE. Results: a significant decrease in TC (198 +/- 33.7 vs. 183 +/- 30.3 mg/dl, p = 0.023) and LDL levels (117 +/- 31.3 vs. 101 +/- 26.2 mg/dl, p = 0.023) were detected after the 3 months of HCQ therapy. The reduction of 7.6% in TC (p = 0.055) and 13.7% in LDL levels (p = 0.036) determined a significant decrease in the frequency of dyslipidemia (26% vs. 12.5%, p = 0.013) after HCQ therapy. Conclusion: This longitudinal study demonstrated the beneficial effect of antimalarials on lipids in SLE since this therapy induced a reduction of atherogenic lipoproteins. Lupus (2012) 21, 1178-1182.

Cytochrome c-promoted cardiolipin oxidation generates singlet molecular oxygen

The interaction of cytochrome c (cyt c) with cardiolipin (CL) induces protein conformational changes that favor peroxidase activity. This process has been correlated with CL oxidation and the induction of cell death. Here we report evidence demonstrating the generation of singlet molecular oxygen [O-2((1)Delta(g))] by a cyt c-CL complex in a model membrane containing CL. The formation of singlet oxygen was directly evidenced by luminescence measurements at 1270 nm and by chemical trapping experiments. Singlet oxygen generation required cyt c-CL binding and occurred at pH values higher than 6, consistent with lipid-protein interactions involving fully deprotonated CL species and positively charged residues in the protein. Moreover, singlet oxygen formation was specifically observed for tetralinoleoyl CL species and was not observed with monounsaturated and saturated CL species. Our results show that there are at least two mechanisms leading to singlet oxygen formation: one with fast kinetics involving the generation of singlet oxygen directly from CL hydroperoxide decomposition and the other involving CL oxidation. The contribution of the first mechanism was clearly evidenced by the detection of labeled singlet oxygen [O-18(2)((1)Delta(g))] from liposomes supplemented with 18-oxygen-labeled CL hydroperoxides. However quantitative analysis showed that singlet oxygen yield from CL hydroperoxides was minor (<5%) and that most of the singlet oxygen is formed from the second mechanism. Based on these data and previous findings we propose a mechanism of singlet oxygen generation through reactions involving peroxyl radicals (Russell mechanism) and excited triplet carbonyl intermediates (energy transfer mechanism).