Lipid (energy) reserves of european hake (Merluccius Merluccius) in the North-Western Mediterranean

This study analyses for the first time the lipid (energy) reserves of European hake (Merluccius merluccius) in the north-western Mediterranean from an ecophysiological perspective. Results show that there is a progressive accumulation of lipids in the liver of maturing hake -where the bulk of the fat is stored- as individuals grow. Results also indicate that female pre-spawners expend much energy on reproductive activities since they present lower liver lipid reserves than juveniles and maturing individuals. Furthermore, results show that female pre-spawners with higher lipid reserves in their livers had a higher amount of lipids in their ovaries, suggesting that maternal condition (spawner quality) may affect the reproductive potential of hake. Overall, the results of this study suggest that the analysis of liver lipid reserves during pre-spawning, along with the evaluation of the gonadosomatic index and the consideration of the reproductive stage, can contribute to improve the estimation of the reproductive potential of gadoid species such as hake

Experimental exposure of the blue mussel (Mytilus edulis, L.) to the toxic dinoflagellate Alexandrium fundyense: Histopathology, immune responses, and recovery

Mussels (Mytilus edulis) were exposed to cultures of the toxic dinoflagellate Alexandrium fundyense or the non-toxic alga Rhodomonas sp. to evaluate the effects of the harmful alga on the mussels and to study recovery after discontinuation of the A. fundyense exposure. Mussels were exposed for 9 days to the different algae and then all were fed Rhodomonas sp. for 6 more days. Samples of hemolymph for hemocyte analyses and tissues for histology were collected before the exposure and periodically during exposure and recovery periods. Mussels filtered and ingested both microalgal cultures, producing fecal pellets containing degraded, partially degraded, and intact cells of both algae. Mussels exposed to A. fundyense had an inflammatory response consisting of degranulation and diapedesis of hemocytes into the alimentary canal and, as the exposure continued, hemocyte migration into the connective tissue between the gonadal follicles. Evidence of lipid peroxidation, similar to the detoxification pathway described for various xenobiotics, was found; insoluble lipofuchsin granules formed (ceroidosis), and hemocytes carried the granules to the alimentary canal, thus eliminating putative dinoflagellate toxins in feces. As the number of circulating hemocytes in A. fundyense-exposed mussels became depleted, mussels were immunocompromised, and pathological changes followed, i.e., increased prevalences of ceroidosis and trematodes after 9 days of exposure. Moreover, the total number of pathological changes increased from the beginning of the exposure until the last day (day 9). After 6 days of the exposure, mussels in one of the three tanks exposed to A. fundyense mass spawned; these mussels showed more severe effects of the toxic algae than non-spawning mussels exposed to A. fundyense. No significant differences were found between the two treatments during the recovery period, indicating rapid homeostatic processes in tissues and circulating hemocytes.

The curcumin analog DM-1 induces apoptotic cell death in melanoma

The main difficulty in the successful treatment of metastatic melanoma is that this type of cancer is known to be resistant to chemotherapy. Chemotherapy remains the treatment of choice, and dacarbazine (DTIC) is the best standard treatment. The DM-1 compound is a curcumin analog that possesses several curcumin characteristics, such as antiproliferative, antitumor, and antimetastatic properties. The objective of this study was to evaluate the signaling pathways involved in melanoma cell death after treatment with DM-1 compared to the standard agent for melanoma treatment, DTIC. Cell death was evaluated by flow cytometry for annexin V and iodide propide, cleaved caspase 8, and TNF-R1 expression. Hoechst 33342 staining was evaluated by fluorescent microscopy; lipid peroxidation and cell viability (MTT) were evaluated by colorimetric assays. The antiproliferative effects of the drugs were evaluated by flow cytometry for cyclin D1 and Ki67 expression. Mice bearing B16F10 melanoma were treated with DTIC, DM-1, or both therapies. DM-1 induced significant apoptosis as indicated by the presence of cleaved caspase 8 and an increase in TNF-R1 expression in melanoma cells. Furthermore, DM-1 had antiproliferative effects in this the same cell line. DTIC caused cell death primarily by necrosis, and a smaller melanoma cell population underwent apoptosis. DTIC induced oxidative stress and several physiological changes in normal melanocytes, whereas DM-1 did not significantly affect the normal cells. DM-1 antitumor therapy in vivo showed tumor burden decrease with DM-1 monotherapy or in combination with DTIC, besides survival rate increase. Altogether, these data confirm DM-1 as a chemotherapeutic agent with effective tumor control properties and a lower incidence of side effects in normal cells compared to DTIC.

Reduced antioxidant defense in early onset first-episode psychosis: a case-control study

Background:Our objective is to determine the activity of the antioxidant defense system at admission in patients with early onset first psychotic episodes compared with a control group. Methods: Total antioxidant status (TAS) and lipid peroxidation (LOOH) were determined in plasma. Enzyme activities and total glutathione levels were determined in erythrocytes in 102 children and adolescents with a first psychotic episode and 98 healthy controls. Results: A decrease in antioxidant defense was found in patients, measured as decreased TAS and glutathione levels. Lipid damage (LOOH) and glutathione peroxidase activity was higher in patients than controls. Our study shows a decrease in the antioxidant defense system in early onset first episode psychotic patients. Conclusions: Glutathione deficit seems to be implicated in psychosis, and may be an important indirect biomarker of oxidative stress in early-onset schizophrenia. Oxidative damage is present in these patients, and may contribute to its pathophysiology.

Dynamic and Regulated Association of Caveolin with Lipid Bodies: Modulation of Lipid Body Motility and Function by a Dominant Negative Mutant

Caveolins are a crucial component of caveolae but have also been localized to the Golgi complex, and, under some experimental conditions, to lipid bodies (LBs). The physiological relevance and dynamics of LB association remain unclear. We now show that endogenous caveolin-1 and caveolin-2 redistribute to LBs in lipid loaded A431 and FRT cells. Association with LBs is regulated and reversible; removal of fatty acids causes caveolin to rapidly leave the lipid body. We also show by subcellular fractionation, light and electron microscopy that during the first hours of liver regeneration, caveolins show a dramatic redistribution from the cell surface to the newly formed LBs. At later stages of the regeneration process (when LBs are still abundant), the levels of caveolins in LBs decrease dramatically. As a model system to study association of caveolins with LBs we have used brefeldin A (BFA). BFA causes rapid redistribution of endogenous caveolins to LBs and this association was reversed upon BFA washout. Finally, we have used a dominant negative LB-associated caveolin mutant (cavDGV) to study LB formation and to examine its effect on LB function. We now show that the cavDGV mutant inhibits microtubule-dependent LB motility and blocks the reversal of lipid accumulation in LBs.

Fsp27/CIDEC is a CREB target gene induced during early fasting in liver and regulated by FA oxidation rate

FSP27 (CIDEC in humans) is a protein associated with lipid droplets that downregulates the fatty acid oxidation (FAO) rate when it is overexpressed. However, little is known about its physiological role in liver. Here, we show that fasting regulates liver expression of Fsp27 in a time-dependent manner. Thus, during the initial stages of fasting a maximal induction of 800-fold was achieved, while during the later phase of fasting, Fsp27 expression decreased. The early response to fasting can be explained by a canonical PKA-CREB-CRTC2 signaling pathway since: i) CIDEC expression was induced by forskolin, ii) Fsp27 promoter activity was increased by CREB, and iii) Fsp27 expression was upregulated in the liver of Sirt1 knockout animals. Interestingly, pharmacological (etomoxir) or genetic (Hmgcs2 interference) inhibition of the FAO rate increases the in vivo expression of Fsp27 during fasting. Similarly, CIDEC expression was upregulated in HepG2 cells by either etomoxir or HMGCS2 interference. Our data indicate that there is a kinetic mechanism of auto-regulation between short- and long-term fasting, by which free fatty acids delivered to the liver during early fasting are accumulated/exported by FSP27/CIDEC, while over longer periods of fasting they are degraded in the mitochondria through the carnitine palmitoyl transferase (CPT) system.

Dietary n-6- or n-3-rich vegetable fats and antioxidants: effects on fatty acid composition and stability of rabbit plasma, liver and meat

We supplemented diets with a-tocopheryl acetate (100 mg/kg) and replaced beef tallow (BT) in feeds with increasing doses of n-6- or n-3-rich vegetable fat sources (linseed and sunflower oil), and studied the effects on the fatty acid (FA) composition, the a-tocopherol (aT) content and the oxidative stability of rabbit plasma and liver. These effects were compared with those observed in a previous study in rabbit meat. As in meat, the content of saturated, monounsaturated and trans FA in plasma and liver mainly reflected feed FA profile, except stearic acid in liver, which increased as feeds contained higher doses of vegetable fat, which could be related to an inhibition of the activity of the stearoyl-CoA-desaturase. As linseed oil increased in feeds, the n-6/n-3 FA ratio was decreased in plasma and liver as a result of the incorporation of FA from diets and also, due to the different performance and selectivity of desaturase enzymes. However, an increase in the dose of vegetable fat in feeds led to a significant reduction in the aT content of plasma and liver, which was greater when the fat source was linseed oil. Increasing the dose of vegetable fat in feeds also led to an increase in the susceptibility to oxidation (lipid hydroperoxide (LHP) value) of rabbit plasma, liver and meat and on the thiobarbituric acid (TBA) values of meat. Although the dietary supplementation with a-tocopheryl acetate increased the aT content in plasma and liver, it did not modify significantly their TBA or LHP values. In meat however, both TBA and LHP values were reduced by the dietary supplementation with a-tocopheryl acetate. The plasma aT content reflected the aT content in tissues, and correlated negatively with tissue oxidability. From the studied diets, those containing 1.5% linseed oil plus 1.5% BT and 100 mg of a-tocopheryl acetate/kg most improved the FA composition and the oxidative stability of rabbit tissues.

Treatment of rats with a self-selected hyperlipidic diet, increases the lipid content of the main adipose tissue sites in a proportion similar to that of the lipids in the rest of organs and tissues

Adipose tissue (AT) is distributed as large differentiated masses, and smaller depots covering vessels, and organs, as well as interspersed within them. The differences between types and size of cells makes AT one of the most disperse and complex organs. Lipid storage is partly shared by other tissues such as muscle and liver. We intended to obtain an approximate estimation of the size of lipid reserves stored outside the main fat depots. Both male and female rats were made overweight by 4-weeks feeding of a cafeteria diet. Total lipid content was analyzed in brain, liver, gastrocnemius muscle, four white AT sites: subcutaneous, perigonadal, retroperitoneal and mesenteric, two brown AT sites (interscapular and perirenal) and in a pool of the rest of organs and tissues (after discarding gut contents). Organ lipid content was estimated and tabulated for each individual rat. Food intake was measured daily. There was a surprisingly high proportion of lipid not accounted for by the main macroscopic AT sites, even when brain, liver and BAT main sites were discounted. Muscle contained about 8% of body lipids, liver 1-1.4%, four white AT sites lipid 28-63% of body lipid, and the rest of the body (including muscle) 38-44%. There was a good correlation between AT lipid and body lipid, but lipid in"other organs" was highly correlated too with body lipid. Brain lipid was not. Irrespective of dietary intake, accumulation of body fat was uniform both for the main lipid storage and handling organs: large masses of AT (but also liver, muscle), as well as in the"rest" of tissues. These storage sites, in specialized (adipose) or not-specialized (liver, muscle) tissues reacted in parallel against a hyperlipidic diet challenge. We postulate that body lipid stores are handled and regulated coordinately, with a more centralized and overall mechanisms than usually assumed.

Liver Glucokinase A456V induces potent hypoglycemia without dyslipidemia through a paradoxical induction of the catalytic subunit of glucose-6-phosphatase

Recent reports point out the importance of the complex GK-GKRP in controlling glucose and lipid homeostasis. Several GK mutations affect GKRP binding, resulting in permanent activation of the enzyme. We hypothesize that hepatic overexpression of a mutated form of GK, GKA456V, described in a patient with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) and could provide a model to study the consequences of GK-GKRP deregulation in vivo. GKA456V was overexpressed in the liver of streptozotocin diabetic mice. Metabolite profiling in serum and liver extracts, together with changes in key components of glucose and lipid homeostasis, were analyzed and compared to GK wild-type transfected livers. Cell compartmentalization of the mutant but not the wild-type GK was clearly affected in vivo, demonstrating impaired GKRP regulation. GKA456V overexpression markedly reduced blood glucose in the absence of dyslipidemia, in contrast to wild-type GK-overexpressing mice. Evidence in glucose utilization did not correlate with increased glycogen nor lactate levels in the liver. PEPCK mRNA was not affected, whereas the mRNA for the catalytic subunit of glucose-6-phosphatase was upregulated ~4 folds in the liver of GKA456V-treated animals, suggesting that glucose cycling was stimulated. Our results provide new insights into the complex GK regulatory network and validate liver-specific GK activation as a strategy for diabetes therapy.