Lipids of the Green Alga BotryococcusCultured in a Batch Mode

The lipid fraction of the green alga Botryococcuscultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerols, sterols and their esters, free fatty acids, and hydrocarbons. In aging culture, the content of polar lipids somewhat decreased and that of triacylglycerols increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C_{16 : 3}and -C_{18 : 3}fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.     

Influence of nitrogen deficiency on biochemical composition of the green alga <Emphasis Type="Italic">Botryococcus</Emphasis>

A study has been carried out to investigate the influence of nitrogen deficiency on intracellular lipid composition, including total fatty acid composition of lipids, polar lipids, and triacylglycerols, of the alga Botryococcus braunii Kütz IPPAS H-252 in batch culture. Under nitrogen limitation, the alga accumulates lipids as triacylglycerols and the total fatty acid (FA) composition changes: trienoic acids decrease (from 52.8–57.2 to 19.5–24.7% of the total FAs) and the oleic acid increases (from 1.1–1.2 to 17.1–24.4%) as does the saturated acids (from 23.7–26 to 32.9–46.1%). A similar rearrangement in the FA spectrum occurs at later times in the control culture, but it is less pronounced. Under nitrogen limitation, considerable changes in the polar lipid FAs are registered at day 13: saturated acids increase (from 28.6–35.5 to 76.8%) and all polyenoic acids markedly decrease (from 56.9–64.1 to 6.8%). Changes in the triacylglycerol fatty acid spectrum are seen on day 7: the oleic acid increases (from 14.7 to 34.2%) and remains at a high level till the end of the culture. In the control, triacylglycerols with large contents of oleic acid are detected at day 13, the total lipids and triacylglycerols still remaining unchanged.     

The effect of phosphate starvation on the lipid and fatty acid composition of the fresh water eustigmatophyte Monodus subterraneus

Phosphate limitation caused significant changes in the fatty acid and lipid composition of Monodus subterraneus. With decreasing phosphate availability from 175 to 52.5, 17.5 and 0 microM (K2HPO4), the proportion of the major VLC-PUFA, eicosapentaenoic acid (EPA), gradually decreased from 28.2 to 20.8, 19.4 and 15.5 mol% (of total fatty acids), respectively. The cellular total lipid content of starved cells increased, mainly due to the dramatic increase in triacylglycerols (TAG) levels. Among polar lipids, cellular contents of digalactosyldiacylglycerol (DGDG) and diacylglyceroltrimethylhomoserine (DGTS) increased sharply from 0.29 and 0.19 to 0.60 and 0.38 fg cell(-1), respectively, while that of monogalactosyldiacylglycerol (MGDG) was not significantly changed. In the absence of phosphate, the proportion of phospholipids was significantly reduced from 8.3% to 1.4% of total lipids, and the proportion of triacylglycerols (TAG) increased from 6.5% up to 39.3% of total lipids. The share of MGDG was substantially reduced, from 35.7% to 13.3%, while that of DGDG and DGTS reduced less from 18.3% to 15.1%, and 12.2% to 8.6%, respectively. The most distinctive change in the fatty acid composition was noted in that of DGDG, where the proportion of EPA, located exclusively at the sn-1 position, increased from 11.3% to 21.5% at the expense of 16:0, 16:1 and 18:1. In MGDG, however, the proportion of EPA did not change appreciably. In contrast to higher plants, DGDG accumulated under P-deprivation in M. subterraneus, did not resemble PC and the positional distribution of its fatty acids was not altered, preserving the C20/C16 structure of its molecular species. We suggest that under phosphate starvation DGTS is a likely source of C20 acyl groups that can be exported to the sn-1 position of DGDG and can partially compensate for the decrease in PE, the apparent source of C20 acyl-containing diacylglycerols in this alga. Moreover, accumulation of non-esterified 18:0 indicates that no polar lipid can replace PC, which appears to be the only lipid capable of C18 desaturation in this alga.     

Effect of Sargassum polycystum (Phaeophyceae)-sulphated polysaccharide extract against acetaminophen-induced hyperlipidemia during toxic hepatitis in experimental rats

The effect of Sargassum polycystum crude extract on lipid metabolism was examined against acetaminophen-induced (800 mg/kg body wt., intraperitoneally) hyperlipidemia during toxic hepatitis in experimental rats. The animals intoxicated with acetaminophen showed significant elevation in the levels of cholesterol, triglycerides and free fatty acid in both serum and liver tissue. The levels of tissue total lipids and serum LDL-cholesterol were also elevated with depleted levels of serum HDL-cholesterol and tissue phospholipid. The acetaminophen-induced animals showed significant alterations in the activities of lipid metabolizing enzymes serum lecithin cholesterol acyl transferase (LCAT) and hepatic triglyceride lipase (HTGL). The levels of liver tissue fatty acids (saturated, mono and polyunsaturated) such as palmitic acid, stearic acid, oleic acid, linoleic acid, arachidonic acid and linolenic acid monitored by gas chromatography were considerably altered in acetaminophen intoxicated animals when compared with control animals. The prior oral administration of Sargassum polycystum (200 mg/kg body wt./day for a period of 15 days) crude extract showed considerable prevention in the severe disturbances of lipid profile and metabolizing enzymes triggered by acetaminophen during hepatic injury. Liver histology also showed convincing supportive evidence regarding their protective nature against fatty changes induced during acetaminophen intoxication. Thus the present study indicates that the protective nature of Sargassum polycystum extract may be due to the presence of active compounds possessing antilipemic property against acetaminophen challenge. (Mol Cell Biochem 276: 89–96, 2005)     

Identification of unusual fatty acids of four alpine plant species from the Pamirs

Fatty acid composition and structure in total lipids from the green above-ground parts of four alpine plants, Oxygraphis glacialis, Primula macrophylla, Rhodiola pamiroalaica, and Swertia marginata, were established by GC and GC-MS. A total of 55 fatty acids was detected, and 48 of them were identified. Ubiquitous palmitate, linoleate, and linolenate predominated in the lipids accounting for about 72-90% of the total fatty acids. At the same time, the latter contained numerous species, which were unusual for higher plants and included saturated odd-numbered n-acids (six C15-C25 species, 0.26-1.40%), saturated even-numbered very-long-chain n-acids (six C20-C30 species, 1.00-2.49%), iso-acids (nine C15-C26 species, 0.64-1.53%), anteiso-acids (four C15-C20 species, 0.08-1.57%), certain uncommon mono- and dienoic acids, as well as 16:3omega3, 18:3omega6, and 18:4omega3 acids that are absent from the most higher plants. Nine fatty acids were found here for the first time in higher plants and two may be new to science. The evidence on the unusual fatty acids is discussed with respect to their distribution in living organisms, pathways of biosynthesis, and chemotaxonomic role.     

Bile acids override steatosis in farnesoid X receptor deficient mice in a model of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and the pathogenesis is still not well known. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily and plays an essential role in maintaining bile acid and lipid homeostasis. In this study, we study the role of FXR in the pathogenesis of NFALD. We found that FXR deficient (FXR^−/−) mice fed methionine- and choline-deficient (MCD) diet had higher serum ALT and AST activities and lower hepatic triglyceride levels than wild-type (WT) mice fed MCD diet. Expression of genes involved in inflammation (VCAM-1) and fibrosis (α-SMA) was increased in FXR^−/− mice fed MCD diet (FXR^−/−/MCD) compared to WT mice fed MCD diet (WT/MCD). Although MCD diet significantly induced hepatic fibrosis in terms of liver histology, FXR^−/−/MCD mice showed less degree of hepatic steatosis than WT/MCD mice. Moreover, FXR deficiency synergistically potentiated the elevation effects of MCD diet on serum and hepatic bile acids levels. The super-physiological concentrations of hepatic bile acids in FXR^−/−/MCD mice inhibited the expression of genes involved in fatty acid uptake and triglyceride accumulation, which may be an explanation for less steatosis in FXR^−/−/MCD mice in contrast to WT/MCD mice. These results suggest that hepatic bile acids accumulation could override simple steatosis in hepatic injury during the progression of NAFLD and further emphasize the role of FXR in maintaining hepatic bile acid homeostasis in liver disorders and in hepatic protection.     

Effect of microalgal diets and commercial wheatgerm flours on the lipid profile of Ruditapes decussatus spat

The influence of both the lipid composition of microalgal diets and commercial flours on the lipid classes and fatty acids of Ruditapes decussatus spat was studied. These aspects of the nutritional value of the diets were discussed in relation to the growth of the spat. Four diets were tested; Diet A, composed of 100% of the daily food ration of microalgae; Diet B, composed of 100% of wheatgerm; Diet C, composed of 50% of microalgae and 50% of wheatgerm; and Diet D, composed of 25% of microalgae and 75% of wheatgerm. The microalgal cells present a higher lipid content than that for wheatgerm. Tahitian Isochrysis cells have phospholipids and triacylglycerols as majority lipids, whereas in the wheatgerm particles, the lipids more abundant are triacylglycerols. Fatty acid content was higher in the microalgal cells than in the wheatgerm particles. The n-3 fatty acids were the most abundant acids in the microalgae, whereas the n-6 fatty acids were in the wheatgerm. The n-3 PUFA were not detected in wheatgerm. Phospholipids were the main lipids present in the clam spat, followed by triacylglycerols. Other lipid classes, detected in significantly lower amounts, included free fatty acids, sterols, and sterol ester + waxes. The composition of fatty acids in the spat was influenced by the fatty acid composition of the diet. Highest spat growth rates were observed with those diets that present a higher phospholipid/triacylglycerol relation. A negative correlation in the relation n-6/n-3 vs. growth has also been observed, with better growth rates in diets with a lower ratio. If the fatty acid 20:5n-3 and 22:6n-3 considered "essential" for marine animals were not present in the diet, they were not present in the spat either. Desaturation and elongation capabilities of R. decussatus spat were also discussed.     

Effects of fish oil on hypertension, plasma lipids, and tumor necrosis factor-alpha in rats with sucrose-induced metabolic syndrome

Dietary fish oil rich in (n-3) fatty acids plays an important role in reducing abnormalities associated with the metabolic syndrome and mortality from coronary heart disease. We investigated the effects of dietary fish oil on the metabolic syndrome in a high-sucrose-fed rat model. The model was achieved by the administration of 30% sucrose in drinking water in male Wistar rats during 21 weeks. After the metabolic syndrome rat model was established, fish oil was administered during 6 weeks. The metabolic syndrome rats showed significant increases in body weight, systolic blood pressure, serum insulin, total lipids, triacylglycerols, cholesterol, free fatty acids, LDL, total proteins, albumin, and serum tumor necrosis factor-alpha (TNF-alpha). They also presented abdominal and epididymal fat accumulation and fatty liver. After fish oil diet administration, metabolic syndrome rats had a significant reduction in blood pressure, serum insulin, triacylglycerols, cholesterol, free fatty acids, and total lipids, but no change was observed in TNF-alpha concentration or fat accumulation. In conclusion, fish oil reversed the alterations on metabolic parameters and blood pressure exerted by sucrose administration, although it had no effect on TNF-alpha production and adiposity. This confirms the theory that the molecular etiology of the metabolic syndrome is multifactorial, as is the effect of n-3 polyunsaturated fatty acids (PUFAs) upon it, having complex and multifaceted actions.     

Effect of increasing amounts of dietary fish oil on brain and liver fatty composition

Increasing dietary fish oil in rat had the following effect on brain lipids: Arachidonic acid regularly decreased; eicosapentanenoic acid, normally nearly undetectable, was present; 22:5(n - 3), dramatically increased but remained below 1% of total fatty acids; cervonic acid was increased by 30% at high fish oil concentration. Saturated and monounsaturated fatty acids were not affected regardless of chain-length. In contrast, in the liver, nearly all fatty acids (saturated, monounsaturated and polyunsaturated) were affected by high dietary content of fish oil, but liver function was normal: serum vitamin A and E, glutathione peroxidase, alkaline phosphatase, transaminases were not affected. Serum total cholesterol, unesterified cholesterol and phosphatidylcholine were slightly affected. In contrast, triacylglycerols were dramatically reduced in proportion to the fish oil content of the diet.     

Effect of methotrexate on long-chain fatty acid metabolism in liver of rats fed a standard or a defined, choline-deficient diet

The effect of methotrexate on lipids in serum and liver and key enzymes involved in esterification and oxidation of long-chain fatty acids were investigated in rats fed a standard diet and a defined choline-deficient diet. Hepatic metabolism of long-chain fatty acids were also studied in rats fed the defined diet with or without choline. When methotrexate was administered to the rats fed the standard diet there was a slight increase in hepatic lipids and a moderate reduction in the serum level. The palmitoyl-CoA synthetase activity and the microsomal glycerophosphate acyltransferase activity in the liver of rats were increased by methotrexate. The data are consistent with those where the liver may fail to transfer the newly formed triacylglycerols into the plasma with a resultant increase in liver triacylglycerol content and a decrease in serum lipid levels. Fatty liver of methotrexate-exposed rats can not be attributed simply to a reduction of fatty acid oxidation as the carnitine palmitoyltransferase activity was increased. The methotrexate response in the rats fed the defined choline-deficient diet was different. There was a reduction in both serum and hepatic triacylglycerol and the glycerophosphate acyltransferase and palmitoyl-CoA synthetase activities. The carnitine palmitoyltransferase activity was unchanged. Hepatomegaly and increased hepatic fat content, but decreased serum triacylglycerol, total cholesterol and HDL cholesterol were found to be related to the development of choline deficiency as the pleiotropic responses were almost fully prevented by addition of choline to the choline-deficient diet. Addition of choline to the choline-deficient diet normalized the total palmitoyl-CoA synthetase and carnitine palmitoyltransferase activities. In contrast to methotrexate exposure, choline deficiency increased the mitochondrial glycerophosphate acyltransferase activity. The data are consistent with those of where fatty liver induction of choline deficiency may be related to an enhanced esterification of long-chain fatty acids concomitant with a reduction of their oxidation.     

Identification of lipids in the cuticle of the parasitic nematode Anisakis simplex and the somatic tissues of the Atlantic cod Gadus morhua

The main aim of this work was to assign the cuticular lipids identified in a parasitic nematode and to distinguish those originating from its host. The hypothesis that long-chained fatty acids and sterols are imported by the parasite in the absence of certain enzymes was also tested. The organisms (Anisakis simplex and Gadus morhua) were extracted in petroleum ether and dichloromethane. Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF) was used to identify unknown components, and electrospray ionization mass spectrometry (ESI/MS) to verify recognized groups of lipids. The lipid classes identified in the surface layer were free saturated and unsaturated fatty acids, triacylglycerols, sterols and non-polar sphingolipids (ceramides, sphingoid bases). The most abundant fraction consisted of fatty acids. The predominant saturated acids were tetradecanoic acid in the petroleum ether extract of A. simplex, hexadecanoic acid in the dichloromethane extract of A. simplex, and also the polyunsaturated octadecahexaenoic and octadecatrienoic acids in both extracts of the parasitic nematode. The mass spectrum revealed the presence of fatty acids with different numbers of carbons, and with odd and even numbers of unsaturated bonds. The MALDI-TOF mass spectrum also identified triacylglycerols (TAGs). The dominant short-chain TAGs were CoCoCy:₁, CoCoPg and Bu0:0B:₆. The majority of TAGs were found in the ether and dichloromethane extracts of A. simplex. Sterols were the least common class of lipids found in the nematode extracts; most likely, this is the fraction that is entirely incorporated from the host organism because of the parasite’s inability to synthesize them. MALDI-TOF also identified non-polar sphingolipids - ceramides and sphingoid bases. The signals due to N-octanoyl-d-erythro-octasphinganine (m/z 288.3) and N-tetranoyl-d-erythro-tetradecasphinganine (m/z 316.4) were dominant on the mass spectra; quite a large number of short-chain non-polar sphingolipids were also identified.     

Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria Glabrata (Gastropoda) infected with larval Echinostoma Caproni (Trematoda)

This study examined the effects of a larval Echinostoma caproni infection on the neutral lipid composition of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails fed hen's egg yolk supplemented with lettuce (Y-L) or lettuce supplemented with Tetramin (L-T). Snails were experimentally infected with the miracidial stage of this echinostome, and their DGGs containing daughter rediae were analyzed for neutral lipids five weeks post-infection by qualitative and quantitative thin-layer chromatography. Light microscopy using Oil Red O (ORO) staining and transmission electron microscopy (TEM) were used to localize neutral lipids in the rediae. The DGGs of infected snails maintained on the Y-L diet showed a significant increase in free sterols and a significant decrease in triacylglycerols compared to uninfected snails maintained on the Y-L diet. The DGGs of infected snails maintained on the L-T diet showed no significant difference in free sterols or triacylglycerols compared to uninfected snails maintained on the L-T diet. ORO staining and TEM showed the presence of lipid droplets in rediae from snails on the Y-L diet. The significant decrease in triacylglycerols in the DGGs of infected snails maintained on the Y-L diet suggests that triacylglycerols were utilized by the rediae.     

Composition of fatty acids triacylglycerols and unsaponifiable matter in Calophyllum calaba L. oil from Guadeloupe

The composition of the kernel oils of two Calophyllum species (Calophyllum calaba L. and Calophyllum inophyllum L.) was investigated. The physico-chemical properties and fatty acid composition of the kernel oils were examined. In two species, oleic acid C18:1 (39.1-50%) is the dominating fatty acid followed by linoleic acid C18:2 (21.7-31.1%) as the second major fatty acid. Stearic C18:0 (13.4-14.3%) and palmitic C16:0 (11-13.7%) acids are the major saturates. The oils contains an appreciable amount of unsaturated fatty acids (70.8-73.10%). Most of the fatty acids are present as triacylglycerol (76.7-84%), twenty one triacylglycerols are detected with predominantly unsaturated triacylglycerols. The total unsaponifiable content, its general composition and the identity of the components of the sterol and tocopherol fractions are presented. In both species, analysis of the unsaponifiable fractions revealed the preponderance of phytosterols, mainly stigmasterol (35.8-45.1%) and beta-sitosterol (41.1-43.1%). Among the eight tocopherols and tocotrienols present in two species, variations exist; alpha-tocopherol (183 mg/kg) is the main tocopherol in Calophyllum calaba L. and Delta-tocotrienol (236 mg/kg) is the dominant tocotrienol in Calophyllum inophyllum L.     

Effect of cholestanol feeding on sterol concentrations in the serum, liver, and cerebellum of mice

In order to elucidate the mechanism of xanthoma formation in cerebrotendinous xanthomatosis, mice were fed for 32 weeks with a diet rich in 5 alpha-cholestan-3 beta-ol (cholestanol) (1%, w/w). The concentrations of sterols in the serum, liver, and cerebellum were determined using high performance liquid chromatography. In the cholestanol-fed mice, the cholestanol concentrations in the serum and liver reached maxima in the first 2 to 4 weeks; the levels were about 30- to 100-fold higher than in the control diet mice. The cholestanol concentrations declined thereafter, finally to 50-60% of the maxima. Cholesterol concentrations were slightly lower in the cholestanol-fed mice throughout the experiments than in the control diet mice. On the other hand, the levels of cholestanol in the cerebellum increased almost linearly in parallel to the feeding time, and no decline was observed. These results suggest that the capacity of the liver to remove or degrade cholestanol was increased by long-term intake of this compound, whereas the cerebellum had no such feed-back regulation. Histological examinations using an electron microscope revealed the enlargement of lysosomal granules in the liver of the cholestanol-fed mice.     

Influence of jute (Corchorus olitorius) seed protein enriched diet on some enzymes and liver lipids of albino rats (Rattus norvegicus)

The effect of protein, isolated from Jute (Corchorus olitorius) seed was studied upon albino rats with respect to some of their serum, liver and intestinal enzymes and liver lipids. An increase in the body weight (including the weight of the liver) was noted in test animals after feeding with a Jute seed protein enriched diet. It was also observed that AST, ALT and total lipid of liver increased significantly whereas AST and ALT of serum were decreased. An increase in the concentration of lipids in the liver was found and this may be due to excess of the seed protein in the diet. An overall observation reveals that there is slight fatty infiltration in the liver of test animals.     

Impact of feeding and starvation on the lipid metabolism of the Arctic pteropod Clione limacina

Feeding and starvation experiments were carried out with Clione limacina sampled in Kongsfjorden (Svalbard, Arctic) during summer 2002. Dry mass and lipid mass, lipid class and fatty acid compositions were analysed. Specimens of C. limacina used for the feeding study had a mean length of 25 mm, a dry mass (DM) of 13.7 mg, and a moderate lipid content of 12.1%DM. Animals were allowed to ingest only one individual of its exclusive prey, Limacina helicina which had 8.0 mm in diameter, 21.4 mg DM and 8.7% lipid of ash-free DM. Five days after feeding, the dry mass of C. limacina had increased from 13.7 to 25.3 mg which corresponds to an uptake of about 80% of the ash-free DM (14.3 mg) of L. helicina. Lipid mass increased from 1.5 to 3.9 mg which is almost two times more the ingested lipid from L. helicina (1.2 mg lipid). Thus, the major portion of lipids was synthesised de novo by C. limacina from non-lipid compounds. These lipids were triacylglycerols (TAG) and 1-O-alkyldiacylglycerol ethers (DAGE), increasing from low proportions of 6.1% and 5.7% to 42.3% and 25.8%, respectively. Considerable de novo synthesis was observed for the monounsaturated fatty acids 16:1(n − 7), 17:1(n − 8), 18:1(n − 9), and 18:1(n − 7) and the alkyl moiety 16:0. The increase in the polyunsaturated fatty acids 22:6(n − 3), 20:5(n − 3), and 18:4(n − 3) corresponded with the amount available by ingestion of L. helicina, supporting that C. limacina is not able to synthesise polyunsaturates. After 15 days of digestion, dry mass and lipids dropped almost back to the initial values.During the 100-day starvation experiment, two groups of animals were separately considered as storage lipid-rich and lipid-poor animals because of their large differences in the amount and proportion of TAG and DAGE. Storage lipid-rich C. limacina were only found until day 50, whereas lipid-poor animals were present throughout the experiment. In the lipid-rich specimens, the levels of TAG were about twice that of DAGE. The proportions of TAG decreased considerably during the 50 days of starvation (from 48.3% to 25.1% of total lipid). DAGE, varying between 16.5% and 20.5%, showed only a small decrease. The lipid-poor animals survived 100 days of starvation, exhibiting low initial amounts and proportions of storage lipids which were nearly exhausted at the end. In all C. limacina specimens, the total lipid content remained almost constant showing that lipid and non-lipid components were simultaneously utilised. This implies that body shrinkage may be an important adaptation to long-term starvation. Based on these results, it is possible to estimate the potential survival period of lipid-rich C. limacina under food limitation. A model, which considers maturity and reproduction (egg production), reveals that lipid-rich specimens might be able to survive up to 260 days without food.     

Improving glycogenesis in Streptozocin (STZ) diabetic mice after administration of green algae Chlorella

Chlorella, a type of unicellular fresh water algae, has been a popular foodstuff in Japan and Taiwan. Studies have shown the hypoglycemic effects of Chlorella in alloxan-induced and Streptozocin (STZ)-induced diabetic animals. However, the mechanisms by which Chlorella treatment affects blood glucose homeostasis have not been studied. Diabetes in ICR mice was induced by injection of STZ. Lipogenesis in vivo was measured by incorporating 3H-H2O into lipids in brown and white adipose tissues. Glucose uptake in the liver and soleus muscles was measured by assaying 2-deoxy-D-[1,2-3H] glucose levels. The effects of Chlorella on serum non-esterified fatty acids (NEFA) were measured with commercial assay kits. Insulin-stimulated lipogenic rates in brown and white adipose tissues were unaffected by Chlorella. However, Chlorella increased 2-deoxyglucose uptake in the livers and soleus muscles in normal and STZ mice compared to that in their respective controls (p < 0.01). In addition, fasting NEFA levels were lower in Chlorella-treated STZ mice compared to H2O-treated STZ mice (p < 0.005). The current results suggest that the hypoglycemic effects of Chlorella are due to an enhancement of glucose uptake in the liver and in soleus muscles. The improved insulin sensitivity after Chlorella treatment could be also due to lower NEFA levels, since insulin sensitivity is usually blunted by elevated NEFA in diabetes.     

Dietary α-tocopherol and atorvastatin reduce high-fat-induced lipid accumulation and down-regulate CD36 protein in the liver of guinea pigs

The increased uptake and storage of lipids in the liver are important features of steatotic liver diseases. The fatty acid translocase/scavenger receptor cluster of differentiation (CD)36 facilitates the hepatic uptake of lipids. We investigated if RRR-α-tocopherol (αT) alone or in combination with atorvastatin (ATV) is capable of preventing hepatic lipid accumulation via down-regulation of CD36. To this end, Dunkin Hartley guinea pigs were fed a control diet (5% fat); or a high-fat control diet (21% fat, 0.15% cholesterol); or a high-fat control diet fortified with αT (250 mg/kg diet), ATV (300 mg/kg diet) or both ATV+αT for 6 weeks. Hepatic triacylglycerols, hepatic protein and mRNA expression of CD36 as well as the mRNA expression of the controlling nuclear receptors LXRα, PXR and PPARγ were determined. Animals fed the high-fat control diet accumulated significantly more triacylglycerols in the liver than control animals. This was significantly reduced by ATV and numerically by αT and ATV+αT. Hepatic CD36 protein concentrations were significantly higher in the high-fat than in the control group, and both αT and ATV reduced CD36 expression to the level observed in the control group. However, no synergistic effect of the combined treatment was observed. Neither CD36 mRNA nor that of the nuclear receptors (LXRα, PXR and PPARγ) differed between groups, suggesting a posttranslational regulatory mechanism. Our results indicate that orally administered ATV and αT individually, but not synergistically, prevent diet-induced lipid accumulation in the liver of guinea pigs by down-regulation of hepatic CD36 protein.     

Effect of the Supplementation of Sulfur Amino Acids to a Diet Containing Soy Protein Isolate on Lipid Metabolism in Rats

The effect of the supplementation of sulfur amino acids to a low casein or soy protein isolate diet on tissue lipid metabolism was investigated. Supplementation of methionine to a 8% casein diet produced a fatty liver in rats, however, supplementation of methionine to a 8.8% soy protein diet (corresponding to a 8% casein diet as to sulfur amino acids content) did not produce a fatty liver. At the level of 8% or less of soy protein in the diet, the accumulation of liver lipids and serum triglyceride was observed. An amino acid mixture simulating the composition of soy protein isolate caused significant accumulation of liver lipids, but serum triglyceride was not changed. Serum cholesterol in rats fed the soy protein diet was lower than that in rats fed the casein diet, but on feeding the amino acid mixtures simulating these protein diets, there was no difference between the two groups. The small differences between soy protein isolate and casein as to lipid metabolism might be due to the small differences in the contents of sulfur amino acids or the specific nature of the soy protein or casein. The supplemental effect of methionine and cystine was also studied. About 60% of total sulfur amino acids could be substituted by cystine for maximum growth.     

Age-related changes of lipid fractions and total fatty acids in the serum of female and male rats aged from 37 to 1200 days

1. Total lipids and the lipid fractions cholesterol ester, triacylglycerols, free cholesterol, free fatty acids and phospholipids as well as the fatty acid patterns of total lipids were measured in the serum of female and male rats (Wistar SPF, strain Hannover) aged 37-1213 days. 2. All parameters were monitored every 49th day. Five female and five male animals were used in each experiment. 3. All lipid fractions showed a significant positive linear regression vs age in both sexes. There were multiple significant differences in lipid fractions between the sexes. 4. Among the fatty acids only docosahexaenoic acid shows a significant correlation with age in both sexes.