Peroxidation products of polyunsaturated fatty acids may cause growth inhibition of cells in culture. This study was carried out to elucidate to what extent peroxidation products may be found in growth media, with and without cells and albumin, using thiobarbituric acid-reactive substances (TBARS) and protein carbonyl groups as measures of peroxidation. The growth of human microvascular endothelial cells was studied as influenced by docosahexaenoic (C22∶6, n−3), arachidonic acid (C20∶4, n−6), and serum albumin. Cell growth was strongly inhibited by the fatty acids, and the inhibition was related to the concentration of TBARS in the medium. Defatted albumin (0.5 g/100 ml) nullified the increase of TBARS in the medium and released the growth inhibition by the fatty acids. With polyunsaturated fatty acids (PUFA) there was a time-and concentration-dependent increase in media TBARS, observed both with and without cells, but the TBARS increase was somewhat greater in the presence of cells. Surprisingly, TBARS in cell-free media also increased somewhat upon increasing the albumin concentration from 0.5 to 5 g/100 ml, and the TBARS increase differed among various preparations of albumin. Unexpectedly, the albumin that had not been defatted gave the lowest TBARS values. The amount of protein carbonyl groups did not differ among various albumin preparations. It is concluded that PUFA may autooxidize in media used for cell cultures, and thereby cause an unspecific growth inhibition, which can be prevented by a low albumin concentration. However, even defatted albumin preparations may contain lipid peroxidation products, the causes and implications of which remain to be elucidated.

Chlorinated fatty acids represent the major fraction of extractable organically bound chlorine in fish. After dietary intake such fatty acids may accumulate in adipose tissue, and even be transferred from mother to child via breast milk. We have previously reported that 9,10-dichloro stearic acid and 5,6-dichloro myristic acid inhibited cell growth. The aim of the present work was to investigate whether the growth inhibitory effect of these modified fatty acids might involve apoptosis. Human hepatoma cells (HepG2) were cultured for 4 days before addition of chlorinated fatty acids, and then cultured for another day before harvested. Morphological analysis was mainly done by light microscopy. In addition, fluorescence microscopy and electrophoretic analysis of DNA were carried out. The effect of 0.3 and 0.6 mmol/l was studied. Both chlorinated fatty acids seemed to cause a concentration-dependent increase in the relative abundance of pycnotic and broken nuclei, as well as nuclear fragments, with the strongest effect of dichloro stearic acid. Apoptosis by the chlorinated fatty acids was however less than that of docosahexaenoic acid, a known apoptosis effector. In conclusion, chlorinated fatty acids seem to possess the ability to cause apoptosis.

Chloro-containing fatty acids are a major fraction of extractable, organically bound chlorine in fish. It has been suggested that dichloro stearic acid (9,10-dichlorooctadecanoic acid) (C18) is metabolized to dichloro myristic acid (5,6-dichlorotetradecanoic acid) (C14) which accumulates in tissues. Hence, the biological effects of the C18 dichloro fatty acid could be due to formation of the C14 dichloro fatty acid. In this study we have compared the effects of dichloro stearic and dichloro myristic acid on growth of three widely differing cell lines. Both fatty acids inhibited cell growth; however, dichloro myristic acid had a weaker growth inhibitory effect than dichloro stearic acid. Dichloro myristic acid had a biphasic effect (i.e. growth was stimulated at low concentrations, followed by inhibition at higher concentrations) on the growth of human hepatoma cells and immortalized human kidney epithelial cells, but no such effect on human microvascular endothelial cells. The order of potency for growth inhibition by dichloro myristic acid was consistently human hepatoma cells>immortalized human kidney epithelial cells >human microvascular endothelial cells, whereas the relative potency of dichloro stearic acid was variable. Albumin alone stimulated cell growth and had a stronger protective effect against growth inhibition by dichloro myristic acid than against that of dichloro stearic acid. It seems unlikely that a major part of the effect of dichloro stearic acid on cell growth is caused by conversion to dichloro myristic acid.

Studies have shown effects of dietary lipids on carcinogenesis and tumour progression. Different mechanisms for the inhibitory effect of n-3 fatty acids (FA) have been: proposed. The inhibition of the growth of subcutaneously transplanted A427 lung adenocarcinoma cells in athymic nude mice may occur due to an increased level of lipid peroxidation products and is the object of this study. The nude mice were fed diets supplemented with corn oil (CO) olive oil (OO) or K85, a: mixture of ethyl esters of n-3 FAs, mainly eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). Tumours of the n-3 FA group showed reduced growth. Peroxidation products measured by the thiobarbituric acid reactive substances (TBARS) test showed higher levels in tumours from n-3 FA fed mice than in the other diet groups. The growth inhibitory effects and the elevated level of TBARS in the n-3 FA diet group were counteracted by vitamin E supplement in the diet. Cu/Zn-superoxide dismutase (SOD) activity in liver did not differ greatly among the diet groups. The Ki-67 labelling index (LI), indicating cell proliferation rate was significantly lower in the K85 diet group compared to the other diet groups.

Chlorinated fatty acids represent a major fraction of extractable, organically bound chlorine in fish. After dietary intake such fatty acids may be transferred from the mother to the foetus through the placenta, and via breast milk to the child. In the present work we have studied the effect of chlorinated oleic acid on the growth of three widely differing types of cells in culture. Chlorinated oleic acid inhibited growth of Human Microvascular Endothelial Cells (HMVEC), Immortilized Human Kidney Epithelial (IHKE) cells, and human Hepatoma cells (HepG2). The order of potency was: HMVEC > IHKE > HepG2. Vitamin E counteracted the inhibitory effect of chlorinated oleic acid on HepG2 cells, but did not significantly affect the fatty acid effect on HMVEC or IHKE. Defatted serum albumin stimulated the growth of HMVEC and IHKE. With HMVEC there was no major interaction between the effect of albumin and chlorinated oleic acid on cell growth. In contrast, with IHKE albumin at low concentration abolished the growth inhibiting effect of chlorinated oleic acid and appreciably counteracted growth inhibition by the fatty acid of HepG2 . We conclude that the growth modulation by chlorinated oleic acid and its interaction with vitamin E and albumin are cell specific.

The objective of this study was to investigate the in vivo relationship between plasma free fatty acid (FFA)/albumin molar ratio and indicators of cellular damage. A case series study was carried out in 20 geriatric patients in a stable clinical condition. Their plasma albumin concentration was in the range 26-42 g l-1. There was a significant positive correlation between the FFA/albumin ratio and (a) reticulocyte count (r = 0.61, p = 0.006), (b) lactate dehydrogenase activity (r = 0.69, p = 0.002), and (c) haptoglobin concentration (r = 0.46, p = 0.05). The haemoglobin concentration was inversely related to relative reticulocyte count (r = -0.55, p = 0.01). Absolute and relative reticulocyte counts were positively associated (r = 0.92, p < 0.0001). The results are in accordance with the contention that a high FFA/albumin ratio in vivo may elicit cellular damage. Further studies are required to elucidate to what extent a high FFA/albumin ratio might be causally related to diseases.

The protective influence of bovine serum albumin against growth inhibition caused by fatty acids was studied in human hepatoma (HepG2) and immortalized human kidney epithelial (IHKE) cells. In general, growth inhibition by unsaturated fatty acids (0.15 mmol/liter) increased with increasing number of double bonds. For HepG2 cells crude albumin (1 g/100 ml) did not greatly modify growth inhibition by arachidonic, eicosapentaenoic, and docosahexaenoic acid. With oleic, linoleic, and linolenic acids, crude and defatted albumin stimulated cell growth. In contrast, for IHKE cells both albumins counteracted growth inhibition by unsaturated fatty acids to approximately the same extent. When HepG2 cells were cultured in the presence of saturated fatty acids (0.3 mmol/liter), C2, C6, and C8 had no or little inhibitory effect. C10 and C12 inhibited cell growth appreciably, whereas C14, and especially C16, had poor inhibitory effects. Crude albumin counteracted growth inhibition by all these fatty acids. In contrast, defatted albumin had little or no effect (except against C10 and C12), and even increased the growth inhibition by C14 and C16. With unsaturated fatty acids there seemed to be an inverse relationship between cell growth and the concentration of thiobarbituric acid reactive substances (TBARS) in media. Vitamin E abolished growth inhibition (and the increase in TBARS concentration) by unsaturated fatty acids. The complex interaction between fatty acids and albumins calls for great caution when interpreting data on growth effects.

The influence of a 3-week vegetarian diet and fasting on serum concentration of peroxides, lipids, apolipoproteins, and plasma fibrinogen was studied in ten middle-aged fibromyalgia/fibrositis patients (eight women, two men). Mean serum peroxide concentration (estimated as thiobarbituric acid reacting substances) was reduced from 3.60 +/- 0.14 to 2.82 +/- 0.15 umol/l (p = 0.01) and plasma fibrinogen from 3.33 +/- 0.25 to 2.74 +/- 0.15 g/l (p = 0.02). Serum total cholesterol fell from 6.61 +/- 0.50 to 4.83 +/- 0.35 mmol/l (p < 0.0001), apolipoprotein B from 1.77 +/- 0.14 to 1.31 +/- 0.11 g/l (p < 0.0001), and apolipoprotein A from 1.41 +/- 0.09 to 1.23 +/- 0.05 g/l (p = 0.03). High density lipoprotein cholesterol concentration also decreased somewhat (from 1.26 +/- 0.09 to 1.07 +/- 0.04 mmol/l, p = 0.03) An atherogenic index, reflecting the balance between low and high density lipoproteins, was reduced by 31% (from 5.74 +/- 0.79 to 3.97 +/- 0.60, p = 0.02). The results suggest that vegetarian diet/fasting may have a beneficial influence on the concentration of serum peroxides and plasma fibrinogen concentration, and on the serum level of several lipoprotein-related coronary risk factors.

Albumin carries fatty acids and has also been suggested to act as an antioxidant. In the present work, polyunsaturated fatty acids (linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids)--but not palmitic and oleic acid--inhibited growth of human hepatoma cells in low albumin concentration (0.5%). Growth inhibition by polyunsaturated fatty acids was prevented by albumin in a dose-related manner in the range 0.7-5.0%. Albumin also protected against growth inhibition following catabolism (by lipoprotein lipase) of very low density lipoproteins. Vitamin E strongly counteracted the inhibitory effect of polyunsaturated fatty acids. Vitamin E and albumin appeared to have additive effects in protecting against growth inhibition by polyunsaturated fatty acids. Indomethacin did not greatly modify the polyunsaturated fatty acids effect. Growth inhibition by polyunsaturated fatty acids, as well as the level of thiobarbituric acid reacting substances (a measure of lipid peroxidation) in growth media, increased with increasing number of fatty acids double bonds. Vitamin E and albumin prevented both thiobarbituric acid reacting substances formation and growth inhibition by polyunsaturated fatty acids. The results suggest that the concentrations of albumin and vitamin E in the incubation medium are essential when studying polyunsaturated fatty acids effects on cell growth.

Sixty-four male, healthy volunteers aged 35-45 y were randomly assigned to receive (as 1-g capsules) either 14 g fish-oil concentrate/d (55% n-3 fatty acids) or 14 g olive oil/d for 6 wk. Plasma fibrinogen was reduced by 13% and serum triglycerides by 22% after fish-oil supplementation ended. Three weeks after supplementation ended both variables were back to baseline values. An appreciable increase in the ratio of eicosapentaenoic acid to arachidonic acid (EPA:AA) in plasma eicosapentaenoic acid to arachidonic acid (EPA:AA) in plasma and red blood cell phospholipids occurred during the fish-oil intake. High-density-lipoprotein (HDL) cholesterol and HDL2 activity tended to be lowered by fish-oil supplementation. Systolic and diastolic blood pressures, serum cholesterol, γ-glutamyltransferase, blood glucose, and monocyte low-density-lipoprotein receptor activity did not differ significantly between the two groups. The reduction in plasma fibrinogen concentration seems of special interest because this variable in several recent studies emerges as a separate cardiovascular risk factor with a high predictive value.

The effect of feeding various diets on plasma lipids and lipoproteins and on fecal excretion of neutral sterols and bile acids was studied in rats fed for 7 wk diets containing 42% of energy as either coconut oil (CO), sunflower seed oil (SO), fish body oil (FBO), cod liver oil (CLO), or a low fat/high sucrose diet (SU). Triacylglycerols (TG) in whole plasma and VLDL + LDL were lower in rats fed high amounts of polyunsaturated fatty acids (PUFA) than in those fed the CO diet. Plasma HDL2 components in FBO and CLO groups were generally lower than in the other groups. Percentages of liver and heart linoleic and arachidonic acid were higher in the SO group, but lower in groups fed marine oils, than in the CO group. There was a high relative amount of eicosapentaenoic and docosahexaenoic acid in liver and heart of rats fed marine oils. Fecal excretion of bile acids was lower in the PUFA groups than in the CO group, whereas the sum of neutral sterols was similar in all groups. Plasma HDL2 (and VLDL + LDL) correlated positively, but HDL3 negatively, with fecal bile acid excretion. Accordingly, increased bile acid excretion does not seem to account for hypolipemia following intake of PUFA diets.

Three groups of 16 male rats were fed for 7 weeks restricted amounts of the same purified diet, but were given either a glucose solution (group A), ethanol/glucose (group B) or beer (group C), so that energy supply was the same in all groups. Ethanol provided 9% of energy in group B and C. Whole plasma triacylglycerol (TG) concentration rose during the initial 2 weeks in group B (to 140%) and C (to 120%); during the rest of the 7 week observation period there was in all groups about the same fall in plasma TG concentration. Values for cholesterol and phospholipids were alike in all groups. Plasma VLDL components were not significantly different in group A and B; group C had lower amount VLDL unesterified (UC) and esterified (CE) cholesterol, as well as phospholipids and TG than group B. LDL-UC and UC/CE ratio was lower in group C than in group A. HDL3-UC and UC/CE was higher in group B than in group A, whereas HDL3-TG was higher in group C than in group A. HDL2 components were similar in all groups. Fecal excretion of cholesterol was reduced in both groups given alcohol. — The results suggest that various alcoholic beverages might influence plasma lipoproteins differently.

When sarcolemma membranes isolated from rat skeletal muscle were incubated with [gamma-32P]ATP, a membrane protein of apparent Mr 95,000 was rapidly phosphorylated, with the 32P content reaching a maximum within 2 s. On the basis of immunoprecipitation with anti-insulin-receptor antiserum, phosphoamino acid analysis and Mr, this protein probably represents the beta-subunit of the insulin receptor. Similarly, on incubation of the membrane with adenosine 5'-[gamma-[35S]thio] triphosphate the 95 kDa protein was thiophosphorylated, indicating thiophosphorylation of the beta-subunit of the insulin receptor on the basis of immunoprecipitation studies. The effect of insulin on the phosphorylation of this protein in the membrane was studied. Insulin induced a 20% decrease in the 32P labelling of the protein when the membranes were phosphorylated for 10 s. This insulin effect was dose-dependent, with half-maximal effect obtained at 2-3 nM-insulin. Addition of GTP, but not GDP or guanosine 5'-[beta, gamma-imido]triphosphate, enhanced the effect to 35% inhibition, with half-maximal effect of GTP obtained at 0.5 microM. GTP had no effect on the phosphorylation of the protein in the absence of insulin. Analysis of this insulin effect showed that insulin increased the rate of dephosphorylation of the 95 kDa protein in the membrane. In contrast, insulin had no effect on thiophosphorylation of the 95 kDa membrane protein after incubation with adenosine 5'-[gamma-[35S]thio]triphosphate. Since thiophosphorylated proteins are less sensitive to phosphatase action, these investigations suggest that insulin stimulated a protein phosphatase activity in a GTP-dependent manner. The possibility that GTP-regulatory proteins are involved in the action of insulin on the phosphorylation of the insulin receptor and other membrane proteins is discussed.

Comparaison de l'excretion de sterols de rats recevant de l'eau, du cafe instantane ou du cafe decafeine instantane. On observe une correlation negative entre l'ingestion de cafe (avec cafeine) et l'excretion de sterols. Le mecanisme d'action de la cafeine au niveau hepatique n'est pas connu