-
[show abstract]
[hide abstract]
ABSTRACT: We previously demonstrated that cultured neonatal rat myocytes have the capacity to desaturate/elongate essential fatty acids, alpha-linolenic acid conversion being higher than linoleic acid conversion. The whole process of highly unsaturated fatty acid formation from linoleic and alpha-linolenic acids slows with aging. In this study we grew heart myocytes in culture for different periods of time, and we observed a decrease in the desaturating/elongating activities for both substrates as the cells aged in culture. Alpha-linolenic acid conversion into highly unsaturated fatty acids was less impaired by aging than linoleic acid conversion. These modifications are correlated to the age-dependent alterations observed in the total lipid fatty acid composition, which caused a decrease in the unsaturation index. Changes in the lipid composition that occur in aging cultures parallel those reported for several tissues upon aging in the whole animal. The data herein reported may suggest the possibility of counteracting the effects of aging on lipid metabolism by supplementing cultures with appropriate amounts of highly unsaturated fatty acids.
Prostaglandins Leukotrienes and Essential Fatty Acids 09/1997; 57(2):143-7. · 3.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In order to evaluate the effect of one of the main oxysterols derived from cholesterol oxidation, cholesterol-5 alpha,6 alpha-epoxide (epox), on cardiac cells, we have supplemented the culture medium of neonatal rat cardiomyocytes with scalar concentrations of epox (0.1-100 microM). While 0.1 microM epox supplementation was ineffective, epox supplementation in the range 1-100 microM determined a reduction in cellular protein level, without affecting cell viability, and a dose-dependent epox incorporation into cardiomyocyte lipids. Furthermore, in the same concentration range of epox supplementation, a gas chromatographic peak unambiguously identified by gas chromatography-mass spectrometry as cholestane-3 beta,5 alpha,6 beta-triol, an hydrolytic metabolite of epox, was detected. The mechanism of cytotoxicity of epox to cardiomyocytes could be due to the insertion of epox itself into cellular lipids, and to its metabolization to the more toxic triol.
Biochemistry and molecular biology international 04/1994; 32(3):565-73.
-
[show abstract]
[hide abstract]
ABSTRACT: A correlation between dietary lipids and cellular enzyme activities is a problem that has only been partially addressed by nutritionists. Therefore, changes in the fatty acid composition and the activities of some key metabolic enzymes (ubiquinol-2-cytochrome c reductase (EC 1.10.2.2), cytochrome oxidase (EC 1.9.3.1) and ATPase (EC 3.6.1.3)) in the mitochondria of liver, heart and brain of rats fed on diets differing extensively in their polyunsaturated fatty acid compositions have been investigated. The results showed that fatty acid compositional changes brought about by the dietary differences were associated with extensive changes in the activities of these key enzymes in the mitochondria. The extent of the influence differed considerably with the period over which the diets were fed. The role of dietary lipids to effect changes through the preservation of membrane structural integrity is discussed.
British Journal Of Nutrition 03/1994; 71(2):193-202. · 3.01 Impact Factor
-
Acta Paediatrica 10/1993; 82(9):789-90. · 2.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study represents the first report indicating that rat heart microsomes contain a measurable delta-6-desaturase activity. The aging process affects delta-6-desaturase activity in the heart to a lesser extent than in the liver, supporting the hypothesis that the regulation of the individual desaturase enzymes may differ in these two tissues. Although decreased desaturase activity, considered alone, may be expected to lower polyunsaturated fatty acid levels, in old animals no modifications in heart microsome fatty acid composition were observed. Probably other metabolic changes may offset this effect, leading to the maintenance of arachidonic acid level in the heart.
Biochemical and Biophysical Research Communications 06/1993; 192(3):1037-41. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Using cultures of beating neonatal rat cardiomyocytes we have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) and we have related it to the previously reported time course of the activation of particulate protein kinase C, in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells treated with docosahexanoic acid. In the cells treated with docosahexanoic acid, the more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexanoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.
Cardioscience 01/1993; 3(4):251-5.
-
[show abstract]
[hide abstract]
ABSTRACT: We have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) in cultures of beating neonatal rat cardiomyocytes, and we have related the acidic pattern to the time course of the translocation of protein kinase C from cytosol to the membrane, both in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells grown in the docosahexaenoic acid supplemented medium. In the control cells, in the early stimulation times, the higher protein kinase C activity was due to a higher relative molar content of arachidonic acid in the diacylglycerol; in the docosahexaenoic acid treated cells the lower but more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexaenoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.
Cardiologia (Rome, Italy) 10/1992; 37(9):631-4.
-
[show abstract]
[hide abstract]
ABSTRACT: In vitro studies have indicated that the 1-stearoyl, 2-arachidonyl diacylglycerol (DAG) is the most effective one for the activation of protein kinase C, although many other DAGs having a different fatty acid composition are active, but to a different extent. Using cultures of neonatal rat ventricular cells, grown in a medium enriched in docosahexaenoic acid (DHA), we previously obtained a cell population that, after alpha 1-adrenoceptor stimulation, produced a DHA enriched DAG. In this study, we have tested the "in vivo" ability of this modified DAG as protein kinase C activator, demonstrating a lower but more persistent translocation of the enzyme from cytosol to particulate fraction in the DHA treated cells. The differences in the PKC activation pattern could be explained by a different metabolism of the DHA enriched DAG by DAG kinase.
Biochemical and Biophysical Research Communications 04/1992; 183(2):893-8. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The influence of three different dietary fats (8%) and of endogenous lipid peroxidation with regard to cholesterol concentrations in liver mitochondria and microsomes and in serum has been investigated in the rat. Although the different diet fat used did not produce any effect on serum cholesterol, it was possible to show that each experimental diet differently influenced the microsomal and mitochondrial levels of cholesterol. The highest mitochondrial and microsomal cholesterol content was found in case of diet supplemented with virgin olive oil and the lowest with rectified olive oil. An endogenous oxidative stress induced by adriamycin was able to produce a clear decrease in microsomal and mitochondrial cholesterol level and a sharp increase in serum concentration in all three groups. However, dietary fats and adriamycin had no effect on the microsomal and mitochondrial membrane viscosity as detected by fluorescence polarization. These results are consistent with the hypothesis that mitochondrial and microsomal cholesterol can exchange with exogenous pools when phospholipid peroxidation occurs.
Life Sciences 02/1992; 50(26):2111-8. · 2.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The effects of oils with different amounts of n6 and n3 fatty acid precursors and derivatives were evaluated on phospholipid composition and PGE2 synthesis of rat kidneys. Dietary lipids were: olive oil, an olive-blackcurrant-fish oil mixture and a blackcurrant-fish oil mixture. We observed in the kidneys of rats fed the blackcurrant-fish oil mixture a significant decrease in PGE2 synthesis, while arachidonate values did not show significant variations. A decrease of PGE2 synthesis could be due to competitive and inhibitory effects of fatty acids other than arachidonate, observed in the kidney phospholipid composition in our dietary conditions.
Prostaglandins Leukotrienes and Essential Fatty Acids 11/1991; 44(2):93-6. · 3.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The possible basal differences in lipid class and fatty acid composition between a cranial nerve (the trigeminal nerve) and two spinal nerves (the ulnar and sciatic nerves) as well as the effects of dietary lipids on the same nerves were studied. A basal (BD) and four experimental diets containing respectively hydrogenated coconut oil (HCO), grapestone oil (GSO), olive oil (OO) and linseed oil (LSO) were used. Trigeminal lipids fatty acid composition differs significantly from sciatic and ulnar ones in the percentages of 16:0, 16:1, 18:0, 18:2 n-6, 20:0, 20:1, 20:4 n-6, 24:0, 24:1 and 22:6 n-3. Also the proportions of triacylglycerols and free cholesterol strongly differ in trigeminal and spinal nerves whereas no significant difference was detected between ulnar and sciatic nerve lipids. Following the administration of the four experimental diets for 60 days, no significant change was observed in the fatty acid pattern of trigeminal lipids while the spinal ones showed a significant increase in the proportions of the fatty acids present in large quantities in the dietary oils used (i.e.: oleic acid in the OO samples). These changes are probably linked with the rapid metabolic turnover of triacylglycerols, present in larger amounts in spinal nerve lipids.
Biochemistry international 02/1991; 23(1):25-34.
-
[show abstract]
[hide abstract]
ABSTRACT: Polyunsaturated fatty acids are involved at several steps in the turnover of phosphatidylinositol mediated by alpha 1-adrenoceptors. We have cultured neonatal rat cardiomyocytes in a medium containing docosahexaenoic acid (C22:6n3) and have investigated the effects produced by the change in the fatty acid composition of phosphatidylinositol on alpha 1-adrenoceptor-mediated phosphatidylinositol metabolism. The experimental cells, in which phosphatidylinositol was significantly enriched in docosahexaenoic acid and depleted in arachidonic acid, showed a reduced ability to incorporate labeled inositol into phospholipids in comparison with control cells, both in basal conditions and after stimulation by phenylephrine. This decreased incorporation led to a reduced availability of inositol phospholipids, substrates of phospholipase C, and to a reduced production of inositol phosphates under basal conditions.
Cardioscience 01/1991; 1(4):235-9.
-
[show abstract]
[hide abstract]
ABSTRACT: The effects of incorporation of dietary oils with different n6/n3 ratio and polyunsaturated fatty acids content into rat liver and brain microsomes has been studied. The investigation of membrane fatty acid composition of liver microsomes and that of brain microsomes gave different results. In particular, liver microsomes of rats fed fish oil showed a relatively higher content of 20:5n3 and 22:6n3, and a lower content of 20:4n6. Under these conditions, a reduced glucose-6-phosphatase activity was measured. Brain microsomal fatty acid composition was only slightly affected by dietary lipid intake. The 5'-nucleotidase activity of those particles was similar, although statistically different values were found in fish-oil-fed rats and in olive-oil-fed rats. The effects of membrane fatty acid composition on membrane-bound enzyme activity are discussed.
The Journal of Nutritional Biochemistry 06/1990; 1(6):305-9. · 3.89 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study is to assess "in vitro" the influence of polyunsaturated phosphatidylcholine on the erythrocyte membrane fluidity in alcoholics (greater than 180 g/die) and control subjects (less than 50 g/die), investigated by the evaluation of fluorescent polarization of DPH. In both groups a significant increase of membrane microviscosity was observed after incubation with 0.04 microM and 0.08 microM of PC compared to baseline values.
La Clinica terapeutica 12/1989; 131(4):233-6. · 0.27 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The first and rate limiting step in the conversion of linoleic and alpha-linolenic acid is catalyzed by the delta - 6 - desaturase (D6D) enzyme. Rat liver microsomal D6D activity decreases on linolenic acid at a rate proportional to the animal age; on alpha-linolenic acid the decrease in D6D activity begins only later than on linoleic acid. The fatty acid composition of liver microsomes determined by gas chromatographic analysis confirms the impairment of the enzymatic activity directly measured. Our data indicate a correlation between aging and D6D activity impairment. The loss of D6D activity may be a key factor in aging through altering the eicosanoid balance.
Biochemical and Biophysical Research Communications 09/1989; 163(1):348-55. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present investigation aimed at clarifying the possible correlations among dietary lipids, peripheral fatty acid composition of nerve lipids and an index of the nervous tissue excitability, the chronaxie. The experiments were performed on female albino rats fed diets containing olive oil (OO) and fish oil (FO) along two generations. Total lipids fatty acid composition of the sciatic nerves from the two groups differed in the proportions of 18:1(n-9), 20:1(n-9), 22-1, 20:5(n-3) and 22:6(n-3). Also the lipid class composition showed significant differences among FO and OO specimens (free cholesterol more concentrated in the OO lipids; triacylglycerols more concentrated in the FO ones). The sciatic nerve isolated from FO rats showed a significant decrease in the chronaxie values if compared to the OO specimens. These results could follow from dietary-induced changes in the perineural permeability and/or possible modifications in the cable properties of the peripheral nerve fibers related to the myelin sheath composition.
Annals of Nutrition and Metabolism 02/1989; 33(2):108-13. · 2.26 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The activity of delta-6-desaturase (D6D) in liver microsomes and fatty acid composition of microsomal lipids of rats of different ages were studied. The D6D activity was similar in suckling rats and in weaning rats. However, the enzyme showed a significantly decreased activity in oldest animals, and a linear correlation was found between the D6D activity and the animal age. The fatty acid composition data on total lipids of liver microsomes were consistent with the age-dependent changes in fatty acid desaturase activity. The major changes occurred in the linoleate and arachidonate fractions; the 20:4/18:2 ratio in liver microsomes decreased together with D6D activity during aging. The loss of D6D activity may be a key factor in aging through altering lipid membrane composition.
Biochemistry international 01/1989; 17(6):1001-9.
-
[show abstract]
[hide abstract]
ABSTRACT: The first and rate limiting step in the conversion of linoleic and α-linolenic acid is catalyzed by the delta - 6 - desaturase (D6D) enzyme. Rat liver microsomal D6D activity decreases on linoleic acid at a rate proportional to the animal age; on α-linolenic acid the decrease in D6D activity begins only later than on linoleic acid. The fatty acid composition of liver microsomes determined by gas chromatographic analysis confirms the impairment of the enzymatic activity directly measured. Our data indicate a correlation between aging and D6D activity impairment. The loss of D6D activity may be a key factor in aging through altering the eicosanoid balance.
Biochemical and Biophysical Research Communications 01/1989; 163:348-355. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Female Wistar rats were fed with diets containing as dietary lipids 10% of hydrogenated coconut oil, grape-seed oil, olive oil, linseed oil and fish oil, respectively, for a period of 60 days. At the end of dietary treatment plasma, platelets and aorta phospholipids were extracted and fatty acid spectra determined. Plasma and platelet phospholipids showed the largest diet dependent changes. Anyway in aorta samples too, phospholipids showed marked increase in oleic (olive oil group) linoleic (grape-seed oil group) and alpha linoleic (linseed oil group) acids percentage. Conversely decreased amounts of arachidonic acid were detected in rats fed with diets containing linseed and fish oils. In these samples eicosapentenoic acid partly replaced arachidonic one.
Biochemistry international 03/1988; 16(2):349-57.
-
Giornale di clinica medica 02/1987; 68(1):23-8.
